Collections of Abstracts of Annual Meeting of the Institute of Electrostatics Japan


Location: Toyohashi University of Technology

Date:   August 29 and 30, 2002/07/27


1s@term@First number is date, and followings are paper number

2rd      English title

3rd      Affiliation

4th      Authors

5th      Abstract




Induction Charging of Droplets by Vibrating Orifice Aerosol Generator     

Hokkaido Inst. Techonol.*, Hokkaido Univ.**             

Takashi SATO* and Yoji NAKAJIMA**      

A small cylindrical electrode is installed at the position of the outlet hole of the head cover of a vibrating orifice aerosol generator. A DC voltage is applied to it so as to induce electric charge on the tip of liquid jet ejected from the earthed micro orifice. Then the liquid jet breaks up to yield charged droplets. In the present experiment, the relation between the droplet charge and the applied voltage to the cylindrical electrode, the effect of streaming electrification on the average and the dispersion of the droplet charge, and the effect of the gap between the orifice and the edge of the cylindrical electrode have

been examined. The results show that

1) The amount of charge due to streaming electrification is simply superimposed on the induced charge, and therefore, a linear relationship between the droplet charge and the applied voltage holds.

2) The charge of the doublet droplets is exactly twice the charge of the singlet.

3) The induced charge seems to take a simple relationship with the location of the cylindrical electrode, but is very sensitive to the state of jet.



Nonlenear ionic-conductivity of polyethylene oxide modified with a mesogenic group and salt

Dept. of Polymer sci. & Eng., Fac. Of Eng., Yamagata Univ.


The purpose of our investigation is to analyze the mechanism of ion conduction in polymer film using the results of nonlinear conductivity measurements.  In this paper, we report on the fabrication of a novel polymer complex film using a salt and present the measurements of the frequency spectra of linear and nonlinear complex conductivities.  The temperature range is from -80C to 80C and the frequency range is from 10 mHz to 10 MHz.  Finally, we describe the results of our analysis of the ion conduction mechanism in the new polymer complex film.  The outlines follows.  On the basis of the existence of the large dielectric relaxation and conductivity relaxation, we conclude that there exists a microscopically inhomogeneous structure that affects ion transport processes in in the new polymer complex film.



Sulfuric Acid Treatment Effect on Surface Charge Decay and Surface Resistivity of Ethylene/Styrene Copolymer Film

Department of Electrical and Computer Engineering, Nagoya Institute of Technology

Yasuro HORI and Mikiya FUKUOKA

A surface of ethylene(65 mol%)/styrene(35 mol%) copolymer film was modified with sulfuric acid. For this film, the increase of surface charge decay has been studied by measuring a series of two-dimensional distributions with time. The decay of charge density on the treated film was faster than that on untreated one, and the surface charges have decayed faster at higher humidity than at lower humidity. The spreading of charges along the surface was clearly observed, and this spreading is the cause of the observed decay of charges. It was proved that the surface charges did not migrate into the bulk of polymer nor evaporate into the air. When the sample film was more strongly modified with sulfuric acid, the surface resistivity could be measured, while the surface charges could not be observed.  The resistivity was also dependent on the humidity and lower at higher humidity. As an example of surface resistivity, a value of 20000 ƒΆ was observed at 40 % relative humidity.



Visualization of Carrier Behavior by Transient Space Charge Measurement             

Toyohashi Univ. of Technology*, Communication Research Laboratory**, Canon***          

Naohiro HOZUMI*, Yuji MURAMOTO*, Masayuki NAGAO*, Kaori FUKUNAGA** and Yuichi HASHIMOTO***             

Carrier species and their mobility are the most important parameters among the electric properties of dielectric and semiconducting materials.   The Hall effect has widely been utilized in order to measure the mobility of semiconducting materials, but it is usually not available for dielectric materials, because their mobility is generally too low to be measured by the Hall effect.   The authors has therefore proposed a new simple method for estimating carrier mobility using a space charge measurement technique.   In this method, the change in time of the space charge profile under a bias voltage is observed after applying a disturbance such as a superposed pulse voltage.    In this paper, we report the result of this measurement on several organic materials.



Phase Diagrams and Displacement Currents of Monolayers on the Water Surface

Faculty of Textile Science and Technology, Shinshu University     

Koki AMANO and Keiji OHARA

Phase diagrams (surface pressure-temperature relationship) were constructed by detecting peculiar points in two-dimensional elasticity-area per molecule curves for many monolayers which consist of molecules with different polar groups bonded to -(CH2)16CH3 linear hydrocarbon chains. Displacement currents generated during compression were compared with the phase diagrams. As results, it seems that the variation in displacement currents corresponds to structural transitions in monolayers.



Charge Generation Mwchanism Based on a Charge Transfer Reaction of Mechano-anions to Mechano-radicals =Effect of a yield of mechano-anion on the substituents-

Ichimura Gakuen College, Nagoya Keizai Univ.

Masato SAKAGUCHI       "Mechanical fracture of polymers in the dark in vacuum at 77 K made them homogeneous and heterogeneous scission of carbon-carbon bond of polymer main chain, and produced macro-neutral free radicals (called mechano-radicals)(1) and macro-anionic species (called mechano-anions).(2-5) The mechano-anions were detected by an electron spin resonance spectroscopy (ESR) using an electron trapping method with tetracyanoethylene (TCNE). Here we show that a yield of the mechano-anion was increased with the degree of ionic character of the carbon-carbon bond in the polymer main chain, in which the ionic character is due to a substituent atom or group attached to the carbon atom. Assuming that a charge separation on the friction surface is induced by the electron transfer reaction from the mechano-anions as an electron donor to the mechano radicals as an electron accepter, the amount of electric charges due to the mechanical fracture of poly tetrafluoroethylene) (PTFE) in the dark in vacuum at 77 K was speculated as to be 1.1‚˜10E-3 C/m2. The estimated value is identical with the speculated maximum values on frictional electricity of polymers, 1.3‚˜10E-3  (6) and 1.7‚˜10E-3  (7) C/m2. The phenomenon that the amount of electric charges of poly (vinylidene fluoride) (PVDF) due to the friction is larger than that of PTFE can be explained by based on their ionic yields.



An Active Oxygen Generation from 12CaO7Al2O3 Surface

The Univ. of Tokyo


Strong, high purity and sustainable atomic oxygen radical anion (O-) emission has been observed from a synthesized microporous crystal 12CaOE 7Al2O3 (named C12A7) surface. In the bulk of the C12A7, numerous of the oxide networks (cages) are made up, where the anion O- and O2- can be stored with a high capacity. O- emission of order of microampere per square centimeter from the C12A7 surface has been obtained at extraction field over 1000 V/cm and surface temperature of 800 ‹C. The O- emission observed is very sensitive both to the surface temperature and applied extraction field. The amount of O- emission is limited by the amount of O-and O2- in cageC12A7. However, by using modified C12A7, which has oxygen electrode, the successive O- emission was demonstrated.



Potential Distribution Around a Rectangular-Prism Electrode by Using GA-Aided Charge Simulation Method Electrical and Electronic Engineering

Tottori Univ.


We have used genetic algorithm (GA) to decide an appropriate arrangement of both fictitious charges and contour points in charge simulation method (CSM).  When polygonal-prism electrode is assumed, an electric field diverges at each corner of the electrode.  Because of this, a contour point cannot be placed nor an electrical potential cannot be determined at a corner of the electrode.   In this paper, we calculated a potential distribution around a rectangular-prism electrode above a grounded plate electrode.  In order to remove above inconvenient, each corner of the rectangle is curved by using a sector with small radii.  We describe the positions of the fictitious charges in Cartesian coordinate system.  The x- and y-components of a charge position are described as genes.  We describe contour point position as a distances along with the outer edge of the electrode cross section from a reference point, which is placed on a side of the rectangle, and the distance is described as a gene. We assigned 30 charges to an electrode with the size of 5 cm x 10cm.  The electrode potential error was about 1% and relatibely accurate solution was obtained.



Improvement of Charge of Powder Particles by Plasma Treatment in Atmospheric Pressure

Tokyo Univ. of Science

Takahiko WATARIC Toshiyuki NAGASAWA and Yuji MURATA

For the purpose of improving the charging characteristics lf polymer powder, we carried out experiment of plasma treatment using two types of discharge, corona and streamer corona discharge, in fluidezed bed. Polyethylene powder of 150 ƒΚm in size was used for the sample. It was found that polyethylene powder tends to charge more negatively by contact and friction with glass beads after the treatments by both plasma and the streamer corona has stronger effect on the charging characteristics of polyethylene powder than the corona discharge. From the results obtained from the measurement of the specific of each particle, it was clarified that almost all the particles were uniformly treated in the present treatment.



Uniformity of plasma treatment of polymer powder particles

Tokyo Univ. of Science

Junichi Okubo and Yuji Murata

Plasma treatment is very effective to improve the characteristics of contact and frictional charging of polymeric materials. In order to apply the plasma treatment to polymer powder, it is most important to use the method for treating all the particles uniformly. The purpose of the present study is to investigate the uniformity of the plasma effect. In order to carry out the experiment, polyethylene powder particles are put into a small glass bottle which has a central bar electrode and a metal net electrode on the outside of it. Powder particles are plasma treated in the bottle by ac plasma generated between the two electrodes.

Using this system, the uniformity of plasma effect is measured for the three cases; (1)

the glass bottle does not rotate, (2)the glass bottle rotates 10 revolutions per second, (3) the particles are mixed with larger glass beads and the bottle rotates. By measuring the specific charge of each particle, it was evident that in the last case almost the all particles are uniformly treated by the plasma.



Charge Storage in a Corona-charged Polypropylene Film Observed by LIPP and TSDC Method

Department of Electronic Engineering, School of Engineering, the University of Tokyo

Ryo ONO and Tetsuji ODA

The charge storage phenomena in a corona-charged polypropylene (PP) film is studied. After a 50 um thick PP film is negatively charged, that charge is measured by the laser induced pressure pulse (LIPP) and the thermally stimulated discharge current (TSDC). The LIPP shows a large negative homocharge at the charged surface. Almost of the homocharge can be removed by dipping the PP film in ethanol, while some amount of the homocharge still remain in 5-8 um depth from the surface after the ethanol treatment. The irrupted depth of the remaining homocharge increases with charging temperature. When the PP film is charged at higher than 80 C, a bulk charge is present inside the PP film. The TSDC spectrum shows not only homocharge but also heterocharge, which is not observed by LIPP. The heterocharge is formed on the charged surface when charged at room temperature. However, the heterocharge is formed also inside the sample when charged at higher than 80 C.



Change in Charging Characteristics of Polyethylene Surface by Streamer Corona Treatment

Tokyo Univ. of Science


The charging characteristics of polyethylene surface are highly changed negative by streamer corona-treatment. The streamer corona has more expensive effect on charging the charge generation by contact and friction in a shorter processing time than the case of ordinary corona treatment because of the high concentration electric power on the sample surface



Charging Characteristics of Polyethylene by N2 Plasma Treatment and Effect of Residual Ga

Tokyo Univ. of Science       ›Hiroteru YANO, Changrag CHOI and Yuji MURATA

The characteristics of polymer surface can be changed by plasma treatment. Low-density polyethylene (LDPE) film treated by N2 plasma showed positive or negative charging tendencies depending on the experimental condition. From the results obtained by N2 plasma treatment using ultra-high vacuum system, it was found that charging characteristics is affected by the residual gas, especially O2 concentration.



Streaming Electrification between various Solid Materials and Insulating oil

Mitsubishi Elebtiric Corporation

Hiroyoshi KITABAYASHI, Kosei TSUJI and Keiichi ITOH

It is a known fact that streaming electrification takes place between solid insulators andinsulating oil flowing in a transformer. In large capacity HV transformers, the streaming electrification can cause high magnitude electrostatic discharges. In order to achieve highly reliable transformers, it is important to understand the streaming electrification phenomenon in transformers. We therefore measured the electrostatic charging tendency of one type of insulating oil flowing on the surface of plates made of several kinds of metals and insulating materials. From these experiments, we obtained the following results. The streaming lectrification of the insulating oil depended on work functions of the solid materials. When the difference in the work function between the each material and the insulating oil was large, the charge density in the insulating oil was large. The equivalent work function of the insulating oil was about 4.0 - 4.5 eV.



Influence of Partial Discharge Pattern on Internal Surface of  an Artificial Cavity on Tree Initiation Properties

*Department of Radiological Technology, Nagoya Univ., **Nagoya Kogakuin College of Technology

*Kuniharu IMAI and **Yukihiro KINOSHITA

In this paper, we discussed relationship between partial discharge on inner surface of an artificial void and tree initiation from its tip. The tree initiation occurs in area where negative charges are accumulated. Voltage dependence of time to tree initiation from an artificial void (V-t characteristic) was obtained. This ependence is realized as linear characteristics which bend at some applied voltages. Each linear characteristic is expressed as logt=-nlogV+logA (A:constant number), which is called a life power low. As an interesting point, the V-t characteristics become discontinuous at 12kV. This is because partial discharge patterns on inner surface of the void change from Polbuschel type to Gleitbuschel type according to the increase in applied voltage. Shape parameters deduced from Weibull probability distribution of the time to the tree initiation were obtained. When the partial discharge pattern was Polbuschel type, the shape parameters were divided into three different values; m<1(early/random failure type) in low voltages, m>1(fatigue failure type) in high voltage. Also the transition voltages of the shape parameters correspond to those of exponents n in V-t characteristics. On the other hand, when the partial discharge pattern is Gleitbuschel type, the shape parameters are divided into two different values; in m>1 low voltage, m<1 in high voltage. Therefore it is apparent that the mechanism of the tree initiation from an artificial void is governed by amplitudes of applied voltages and the partial discharge pattern.



Restriction of Tree Degradation by Additive of Aromatic Compound

Faculty of Education, Chiba Univ.

Megumi ISHIGAKI and Yoshiaki YAMANO

The aromatic compound was added to LDPE with the concentration of 0.5wt% to restrict the tree propagation in LDPE.  The compound used were anthracene and 9,10 Bromo-anthracene.  AC(50Hz) high voltage was applied to a needle electrode inserted to LDPE block with the additive.  The experimental results show that the tree inception voltage for the specimen with anthrasene is 2.5 or 3.5 times higher than that for the specimen without additive.  The propagation of tree in LDPE at the tree inception voltage is restricted by the addition of the compound.  The number of pulse in the PD current due to the tree generation is also decreased by the addition of the compound.  The number of the pulse in the LDPE with anthracene is 0.2-0.3 times less than that in the LDPE without the additive.



Aging on inner surface of an artificial void exposed to partial discharge

Nagoya Kougakuin College of Technology*, Nagoya Univ.

Yukihiro KINOSHITA*, Kuniharu IMAI** and Yoshihiro HIRAISHI*

In this paper, we discussed degradation process of polymer caused by partial discharge in an artificial void which improved on Whitehead abc model. Size of aging area on inner surface of the artificial void increases with time and becomes constant. After that, the size of the aging area increases steadily. A residual charge distribution (Dust Figure) on the inner surface of the artificial void was obtained using copy-toner which attaches to negative charges. The size of the residual charge distribution increases dramatically and then levels out Tree initiates when the size of the aging area corresponds to that of the residual charge distribution. In order to these results, time variation in charges of maximum discharges and the number of partial discharge pulses in the artificial void were measured. The charges of maximum discharges are almost constant regardless of time under application of constant voltages. On the other hand, time variation in the number of partial discharge pulses in the artificial void is similar to the change of the aging area size. This result confirmed the number of the partial discharge pulses concerns deeply with formation of the aging area on the inner surface of the artificial void.



Benzen Decomposition using Ozone and MnO2

Central Research Institute of Electric Power Industry

Naohiko GOTO and Satoshi KUDO

MnO2 decomposes O3 and produces O atom. O atom decomposes C6H6. In this study, C6H6 decomposition has been investigated using O3 and MnO2.  The C6H6 in the N2 is mixed with O3 produced by the ozonizer.  When the mixed gas passes through MnO2, the C6H6 is decomposed.  The amount of C6H6 decomposition increases with increasing amounts of O3.  From the check of mass balances of C, H, and O, we found that O3 effectively decomposes C6H6 into CO, CO2, and H2O.



Removal of Formaldehyde by DC Streamer Corona Discharge

Toyohashi Univ. of Technology 

Karol Hensel, Kazunori Takashima and Akira Mizuno

Formaldehyde (HCHO) is an air pollutant, which contributes to the formation of photochemical pollution. In addition, chronic or acute exposure to formaldehyde (an anticipated carcinogen) constitutes an important health hazard. Decomposition of formaldehyde by non-thermal plasma of DC streamer corona discharge was studied experimentally. A combination of plasma and catalyst for improvement of the decomposition was partially investigated too.



Removal of Fluorocarbons by Surface Discharge Plasma Reactor with Catalyst and Various Additives

*National Institute of Advanced Industrial Science and Technology ** Industrial Technology Center of Nagasaki

Atsushi OGATA*, Hyun-Ha KIM*, Hajime KINOSHITA*, Shigeru FUTAMURA*, Satoshi KUSHIYAMA* and Koichi MIZUNO**

The decomposition of 1% fluorocarbons in Ar was investigated using a surface-discharge type plasma reactor. In particular, in order to enhance the effectiveness of plasma chemical processing, we investigated the effects of catalyst packed in the reactor and second gases added in the reactant. Removal efficiency increased in the plasma reactor packed with TiO2 pellets, whereas no positive effect was observed with Al2O3 or S-Al2O3 pellets. Furthermore, removal efficiency was also enhanced when the additive gases such as water, oxygen, and hydrogen introduced to the carrier gas (Ar). The presence of TiO2 and/or a second gas depressed the formation of byproducts. From product distributions, it was suggested that those enhancement effects were caused by preventing the recombination of decomposed fragments.



Destruction of Perfluoro Compounds by Atmospheric Pressure Plasma

Advenced Technology R&D Center*, Communication Systems Center**, Mitsubishi Electric Corporation

Yasutaka INANAGA*, Koji OHOTA*, Noboru WADA*, Masashi DOI*, Kiyohiko YOSHIDA** and Masaki KUZUMOTO*

We estimated the abatement of perfluoro compound (CF4) by a microwave induced thermal plasma and a narrow gap silent discharge under an atmospheric pressure experimentally.  The destruction efficiency by thermal plasma (2.8X10(2)eV/molecule)@was over ten times higher than that by silent discharge in the case of the nitrogen@dilution.  Near 100% abatement was proved by microwave induced plasma under the wide flow rate range.



Effective Combination of Nonthermal Plasma and Catalyst

*National Institute of Advanced Industrial Science and Technology

Atsushi OGATA, Hajime KABASHIMA, Hisahiro EINAGA, Shigeru FUTAMURA, Satoshi KUSHIYAMA and Hyun-Ha KIM

The effective combination of plasma energy and solid surface properties was investigated using packed-bed type catalyst-hybrid and adsorbent-hybrid reactors that were packed with the mixture of BaTiO3 pellets and other ceramic pellets (catalyst or adsorbent). The plasma reactor using catalysts indicated the improvement of CO2 selectivity and the suppression of N2O formation compared with the reactor packed with BaTiO3 alone. Furthermore, the catalyst and adsorbent positions in plasma reactor were very important for the induction of surface reaction on the packed materials. It was found that the catalysts and adsorbent in the plasma reactor were useful in changing product selectivity and enhancing energy efficiency.



Flue Gas Treatment og Semiconductor Process using Inductively Coupled Plasma

Dept.Energy Systems Eng., Osaka Pref. Univ.*, Pearl Kogyo Co.,Ltd.** 

Tomoyuki KUROKI*, Junko MINE*,  Noboru SAEKI**,  Masaaki OKUBO* and Toshiaki YAMAMOTO*

CF4 decomposition was investigated at low pressure (~53 Pa) using the inductive coupled plasma (ICP) reactor, which can be used to generate remote plasma in wafer etching process and to clean the chamber. When the total flow rate was below 0.26 SL/min, more than 90% of CF4 decomposition efficiency was achieved with O2/CF4=1.1, p=40 Pa and Power=1.2 kW. However, when the total flow rate exceeded 0.26 SL/min, the CF4 decomposition efficiencies decreased. More than 1.25 kW was required in order to achieve the complete CF4 removal when the total flow rate was 0.24 SL/min, O2/CF4=1.1 and p= 40 Pa. The optimum amount of O2 additive was about the same stoichiometric or somewhat more amount of CF4. The Ar additive enhanced the CF4 decomposition, but He additive was insignificant. The N2 additive caused to decrease the CF4 decomposition efficiency.



Generation@of Hydrogen from Methane and Water in a Dielectric-Barrier Discharge-Plasma System

Daido Steel Co.,Ltd.

Kanji IRIE and Takayoshi SHIMIZU

The decomposition of CH4 was investigated in a dielectric-barrier discharge-plasma system. To generate much quantitative hydrogen, there arose the necessity of big flow rate and high concentration of source gas, but It loses hydrogen yield according to increasing of flow rate and concentration.  At first it is considered due to the shortage of reaction volume. But volume dependency can not be improved for 10, 14.5 , 50 diameter reactor. In addition, to expand to long size and volume, double layered plasma developed failed to increase hydrogen yield. Only corona adopted and arc adopted reactor showed preferable yield. Focus ring attached arc system named micro arc jet (MAJ) in which gas flow along electrode methane molecule move at speed of 100 cm/sec when flow rate is 1L/min. And, reaction time can be estimated to be shorter than 3msec. it saved expense of electric power from 200 W to 20 W. It is notable 3 W generates 16.5 W for fuel cell.. it is observed that the curve of flow rate dependency is obviously refined by using Cascade.



Steam Reforming of Hydrocarbons with Nonthermal Plasma

National Institute of Advanced Industrial Science and Technology

Shigeru FUTAMURA, Hajime KABASHIMA and Hisahiro EINAGA

Steam reforming of methane, ethane, propane, and neopentane was investigated withtwo types of nonthermal plasma reactors.  With a ferroelectricpacked-bed reactor (FPR) in N2, almost the same conversions were obtained for ethane, propane, and neopentane, but methane wasless reactive than these hydrocarbons.  Hydrogen gas yield decreased in the order: methane ƒi ethane > propane > neopentane.  The molar ratio of H2 to CO {[H2]/[CO]} exceeded 3.5 for allthe hydrocarbons.  [H2]/[CO] did not change in the range of H2O content from 0.5 % to 2.5 %.  At the volumetric ratio of H2Oto Hydrocarbon = 2.0, carbon balances were poor for ethane, propane, and neo|‚‚…‚Ž‚”‚‚Ž‚…, but almost all of the carbon atoms in the reactedmethane were recovered as CO and CO2.  The selectivities of COand CO2 depended on the chemical structures of the substrate hydrocarbons.  It is considered that the water-gas-shift reaction proceeds backward for the reaction systems of hydrogen-rich hydrocarbons.  FPR maintained the same performance for 10 h in the steam reforming of methane.  The efficiency of a silent discharge plasma reactor was much lower than that of FPR.



The Role of Gas-phase Reaction in TiO2 Photo Catalyst

Toyohashi University of Tech. Ecological Engineering Teaching Associates Wataru Minami"    Wataru MINAMI and Hee-Hoon KIM

The photocatalytic degradation of Ethylene and Trichloroethylene(TCE) were studied. The ultraviolet and titanium dioxide (TiO2) was simultaneously utilized to promote their decompositions. As the results, the main reaction of TCE decomposition is the gas-phase reaction by ultraviolet and Ethylene decomposition is surface reaction on photocatalyst. Trichloroethylene promote Ethylene decomposition by surface reaction on photocatalyst. When the ultraviolet irradiated on surface of TiO2 particles, components of decomposed Trichloroethylene promote Ethylene decomposition. The decomposition reaction of Trichloroethylene was not a chain reaction in gas-phase.



Odor Removal and Regeneration of Filter using Nonthermal Plasma

Dept.Energy Systems Eng., Osaka Pref. Univ.*, Pearl Kogyo Co.,Ltd.** 

Shinsuke UMEI*, Yoshihumi MORITA*, Noboru SAEKI**, Tomoyuki KUROKI*, Masaaki OKUBO* and Toshiaki YAMAMOTO*

Hydrophilic monomers are graft-polymerized to the surface of the cloth after the plasma application. The characteristics of the cloth changes to breathe moisture and to increase the adsorption of offensive odor simultaneouslyDIn the present studyCan improved method for preparing this functional cloth and experimental results of moisture and odor control properties are studied using a typical odor component NH3DMoreover, the regeneration characteristics of the cloth used for bag filter was investigatedDAs a resultCthe adsorption efficiency was significantly improved with plasma application and regeneration of odor removed characteristics of the cloth was confirmedD



NOxOxidation/Reduction by Magnetized Trench Type Dielectric Barrier Discharges

Dept. of Engineering Physics, Mcmaster Univ.* Research Lab., Ford Motor Company**

Kuniko URASHIMA*, John W. HOARD** and Jen-Shih CHANG*

An experimental investigation has been conducted to enhance plasma catalytic NO oxidation and reduction by trench type electrode dielectric barrier discharge (DBD) reactors with and without external magnetic fields. In a trench type DBD reactor, the discharge occurs at sharp edges near barrier electrode and major chemical reactions take place at ditch space between each triangle. Therefore, electrons only contributed radical generations but not destruct radicals in afterglow regions, hence, effectively used in ozonizer applications. On the other hand, an electron motion also can be controlled by a magnetic field (>0.01T) in atmospheric gas pressure and many attempts have been applied to control corona and barrier discharges. Experiments were conducted for applied voltage from 0 to 17kV, operating frequency 60 and 7kHz and gas flow rate from 1 to 10 LPM with and without 0.1T permanent magnets under simulated exhaust gases. The results show that the effective input energy to non-thermal plasma increases with applied voltage, operating frequency and magnetic field intensity and hence the energy efficiency of NO oxidation/reduction increases with these parameters.



Wide Range Measurement of NO Molecules in Atmospheric Pressure DC Streamer Coronas by Laser-Induced Fluorescence

Department of Electrical and Electronic Engineering, Oita Univ.*, Institute of Fluid Flow Machinery, Polish Academy of Sciences**, Department of Engineering Physics, McMaster Univ.***       

Narukaki SATO*, Tomoyoshi SUMI*, Seiji KANAZAWA*, Toshikazu OHKUBO*, Yukiharu NOMOTO*, Jerzy Mizeraczyk** and Jen-Shih Chang***

NO density profiles in DC streamer coronas have been investigated by laser induced fluorescence method. It was found that NO moleculeconcentration decreased not only in the plasma region created by the@streamers but also in the upstream region of the discharge. In this study,@in order to further investigate the upstream region of the reactor, wider@LIF images were acquired that had a LIF observation area corresponding to@the 34cm-long by 5cm-height. As a result, it was found that NO depletion@region spread over an upstream region with a distance that is a few times of@the gap distance. This was due to the higher velocity of the secondary flow, which squeezed the main gas flow with low velocity.



Simultaneous Treatment of Soot and NOx by SPCP Reactor

Faculty of Engineering, Soka Univ.


We developed an efficient apparatus for gas treatment in which a ceramic filter and SPCP (Surface corona discharge induced Plasma Chemical Process) were combined.  SPCP is a method to activate a gas-phase chemical reactions with surface discharge plasma.  This method has some advantages such as stability even under atmospheric pressure and at room temperature, and simplicity of the reactor structure, and the apparatus constructions.  In this study, the applicability and possibility of this method to treatment of soot and NOx simultaneously were examined.  It was confirmed that soot and NOx could be removed effectively, simultaneously, and complementary.  This measns that NO2 works as the oxidizer of soot in this simultaneous treatment of soot and NO2, and therefore soot was oxidized to the CO2 and CO.



Characteristics of NOx Concentration by Zeolite and NOx Decomposition by Microwave Thermal Plasma

Mitsubishi Electric Corp. Advanced Technology R&D Center


Breakthrough characteristics of NO2 adsorption by H-Y high-silica zeolite@have been studied. H-Y zeolite is reactivated by heating and decreasing@pressure. Desorption gases are concentrated 14,000 times. Then@characteristics of NOx decomposition by microwave thermal plasma have been@studied. NO2 with a concentration of 20% is decomposed into nitrogen and@oxygen and decreases to 4%. The energy consumption is approximately@15eV/molecule.



Oxidation of SO2 by Using the Hybrid Reactor of Plasa and Catalyst for New Dry Desulfurization Process

Ecological Engineering, Toyohashi Univ. of Tech.*, Shinko Pantec Co.,Ltd.**

HeeJoon KIM*, Yuhei SAKAGUCHI** and Wataru MINAMI*

To find out a new dry-type desulfurization process with high efficiency and cost performance, a hybrid type reaction process combining pulsed streamer corona plasma and TiO2 catalyst was developed in order to oxidize SO2 to SO3. Experiments of V2O5EK2OETiO2 surface-reaction with/without plasma was performed to increase oxidation rate. Experimental results show that the oxidation fraction of SO2 to SO3 in the catalytic surface reaction is increased significantly, when plasma was applied to the reaction zone. The oxidation fraction is decreased by adding H2O of above 0.2% by volume. Hydrogen peroxide was not promoting oxidation fraction in comparison to the addition of H2O.



Numerical Simulation of NO Decomposition by Streamer Discharge in N2 at Atmospheric Pressure

Department of Electrical Engineering, School of Engineering, The University of Tokyo

Go YAMADA, Kazuo SHIMIZU ad Tetsuji ODA

Non-thermal plasmas are effective in decomposing toxic gaseous contaminants in air or combustion gas. However the physical properties of non-thermal plasmas are not yet sufficiently understood. The streamer propagation in $N_2$ and $NO$ decomposition phenomena were investigated by using the one-dimensional numerical simulation technique. Light emission of second positive band (SPB) and first negative band (FNB) were displayed. Generation of a large amount of N@radicals was simulated in the streamer head, while low energy level excited species such as N2(A‚R\ƒ°u+ are made on the surface of each electrode. Decomposition of NO by N radicals were well demonstrated.



Reduction of NO3 on Wet Type Plasma Discharge Using Fe Electrode

Toyohashi Univ. of Technology


NO3- is reduced by electrolysis using Fe electrode in acid condition, and NH4+ is roduced. In this paper, NO3- reduction was carried out by discharge plasma using Fe plate. The underwater discharge reduced NO3- more than the discharge over liquid surface. Concentration of NH4+ in solution changed with size of the Fe plate. NH4+ was reduced from NO3- by the discharge plasma more effectively than electrolysis. Using Al plate and Cu plate on the contrary, NO3- was not reduced to NH4+.



Regeneration of Ciesel Particulate Filter using Nonthermal Plasma without Catalyst

Dept. Energy Systems Eng., Osaka Pref. Univ., Automotive and Industrial Ceramics Division, NGK Insulators, Ltd.*

Masaaki OKUBO, Takayuki MIYASHITA, Tomoyuki KUROKI, Shinichi MIWA* and Toshiaki YAMAMOTO

The regulation for the automotive diesel engine emission becomes severe every year, and it is difficult to meet the requirement only by the combustion improvement techniques in the near future. More effective post-processing technology is desired especially on particulate matter (PM), such as carbon soots. Although the use of ceramic diesel particulate filter (DPF) is now a leading technology for PM removal, the problem exists on the soot removal or regeneration at low temperature, especially at the cold start. In the present study, a regeneration of DPF with collected PM was investigated using the low temperature atmospheric pressure nonthermal plasma. The method is to use the NO2 and radicals induced by the plasma reactor to burn carbon soots deposited on DPF. First, three types of DPF plasma reactors were made and the performances on the conversion of NO to NO2 were evaluated on various conditions. Next, a regeneration experiment was carried out using a barrier type pulse corona plasma reactor. As a result, it was confirmed that the pressure difference decreased only when the plasma was turned on and the regeneration of DPF was realized less than 250‹C



Nox Removal Using Discharge Plasma and Electric Conduction

Toyohashi Univ. of Technology

Zhenzhou SU, Jun SAWADA, Kazunori TAKASHIMA, Shinji KATSURA and Akira MIZUNO

A novel reduction process for deNOx was investigated in this study. The reactor was consisted by two part; the discharge plasma reactor and the adsorption cell. The NO was oxidized to NOx using the pulsed discharge plasma. Then, the removal of NOx was realized by the adsorption to the ganma alumina and the alkali metal. To keep the activity of the adsorbents, a method using the electric conduction was tested in this work. In the NOx oxidation process, about 70% to 90% of NO (initial concentration of 400ppm) was oxidized to NO2 by the pulsed discharge plasma with the specific input energy of 45J/L, and about 95% of NO2 was adsorbed on the adsorbents. When the DC voltage was applied to the wet adsorbents, the nitrate ion was moved to the anode side of the absorption cell by the electric conduction, and the sodium ion was moved to the cathode side.



A Capacitive Type of Electrostatic Induction Spraying Nozzle

School of Electronic & Electrical Engineering, Kyungpook National Univ., * National Agricultural Mechanization Research Institute, ** Dept. of Agricultural Machinery Engineering, Chungbuk National Univ.,

 Jong-Hoon Lee, Jae-Duk Moon, *Tae-Gyoung Kang, *Dong-Hyeon Lee, and **Kwang-Seok Yon 

Many toxic pesticides are dispensed for the protection of food crops from pests in farm fields. Greater than 90% of pesticides are commonly applied as aqueous-based sprays. When dispensed with conventional nozzles, a large portion of the spray is often lost as airborne drifts of droplets. In addition, there is a lack of deposition onto the plants due to the rapid gravitational settling of droplets beneath the soil surface. Thus, target deposition efficiencies poorer than 25% are often encountered in agricultural pesticides. An electrostatic spraying technology offers a very favorable means of increasing pesticide droplet deposition onto biological surfaces of living crops

In this paper, a new capacitive type of electrostatic spraying nozzle, which utilizes a ring induction electrode installed on the outside of a nozzle frame cone and a pulsed voltage, is proposed and studied experimentally. The results of this study indicate that the proposed capacitive type of electrostatic spraying nozzle showed a large current deposition of aqueous sprays on the sample target. Thus, it has promise to be applied as an effective electrostatic spraying nozzle.



Thermally Stimulated Current Spectra of Hot Pressed Powder Paint Compacts

Keio Univ.

Masayuki@KARASHIMA@and@Kazuo IKEZAKI

We Examined thermally stimulated current(TSC) spectra of commercial powder paints compacts which were pressed at a compacting pressure of 0.16MPa under different compacting temperatures ranging from 50 Ž to 100Ž. Observed TSC spectra have a large band BH peaked around 70Ž for relatively low compacting temperatures, while the peak temperature of this BH band shifted to the low temperature side and a new TSC band BL appeared around 50Ž when the compacting temperature increased. The peak temperature of the new TSC band corresponds to that of the melt-cast sample at 110Ž. The newly observed TSC band BL was explained in terms of inter-particle polymer chain diffusion.



Free Ion Absorption Characteristics of an Irrigated Grid Using for Absolute Measurement of Q/M Ratio of Charged Paint Particles from Corona Gun

*Zao ES Laboratory,@**Department of Electrical and Electronic Engineering, Tokyo University of

Agriculture and Technology,@***I. D. P., Inc. "

Mitsuru MATSUI*, Koichi FUJIBAYASHI** and Tsutomu ITO***        

A stream of paint particles blown from corona charged powder applicator is accompanied by a lot of free ions generated from corona discharge.  To realize absolute measurement of charge to mass ratio of the particles, therefore the free ions must be removed from the stream before these arrive to the particle collector.  This paper describes design of a grid electrode to extract the free ions from the stream and its ion absorption characteristics.  The grid electrode is made of stainless steel wires of 0.3 mm in diameter and arranged in parallel at uniform intervals of 10 mm, and whose each wire is irrigated with water so as to remove the powder particles deposited on its surface



Stabilization of Characteristics of Electrostatic Separation System of a PET Bottle in the Form of FlakesTokyo Metropolitan Industrial Technology Research Institute

Yasuo TONOYA, Katsumi YAMAMOTO and Hiroshi SHIGEMATSU    Waste PET bottles are converted into PET flakes as recycling materials in processing industry. Waste PVC bottle flakes are generally mixed into waste PET bottle flakes as an impure ingredient. It is indispensable for recycling PET bottles flakes to remove PVC bottles flakes from the mixed plastic waste. The authors made the electrostatic separation system of a PET bottle flakes. The electrostatic chargeability of plastics is influenced by environmental conditions, such as relative humidity. When the relative humidity in the working room of the electrostatic separation system increases more than 60%R.H., the charge quantities of flakes decrease. As the result, the separating efficiency falls drastically. The prevention methods against the lowering of separaing efficiency are discussed. We tried to dehumidify the wet atmosphere in the working room by operating dehumidifieres, and the separating efficiency has been improved. When the relative humidity of atmosphere is controlled under 45%R.H., the extract content is over 99.99% and the recovery is over 70%.



Experimental Study of Pearl-chain Adhesion Phenomenon in Electrostatic Field        Experimental Study of Pearl-chain Adhesion Phenomenon in Electrostatic Field

Dalian University of Technology*, @Toyohashi Univ. of Technology**

Guofeng LI *, Kazunori TAKASHIMA**, Shinji KATSURA**, Arkira MIZUNO **

Using the electrostatic force of forming pearl-chain, the adhesion of Al2O3 fine powder (average particle diameter 0.3 ƒΚm) in the form of pearl-chain to the surface of a metal mesh and an Al2O3 substrate (10 mm~10 mm~5 mm in size ) was experimentally studied. The results showed that the adhering process of pearl-chain to the material surface could be controlled using electrostatic force, and it is possible to fabricate ceramic membrane utilizing the pearl-chain adhesion phenomenon. Keywords: electrostatic force, adhesion, pearl-chain



DPE liquid actuation and nanodroplet formation in insulating oil

Toba National College of Maritime Technology*, Univ. og Rochester**    

Tomohito ITO* and T. B. JONES**

The dielectrophoretic(DEP) force acting on a liquid provides a controllable means for rapid movement and dispensing of small liquid volumes on a substrate. DEP microactuation @of liquids requires strong non-uniform rf electric fields created by co-planar electrodes.  Microliter volume of water deposited on an insulating layer that covers the coplanar electrodes are transported and subdivided into droplets as small as 1`5 nl by sequences of voltage on and off.  Experiments are conduced using substrates having the electrodes immersed in transformer oil.   Observation of movement of water and droplet formation is made in various field conditions.   The minimum voltage for DEP actuation of water in oil is 65-70% of that in the dry condition, and nanoliter droplets are formed.  Evaporation of transporting liquid and formed droplets are also avoided.



Mixture of Minute Solutions in a pl Order Droplet by Use of Electrostatic Force

Hamamatsu Photonics

Osamu YOGI and Tomonori KAWAKAMI

It is an important technique to mix minute solutions in a droplet in the field of combinatorial chemistry. However, the smaller droplet, it is more difficult to mix solutions homogeneously due to surface influence. To solve this problem, a novel technique for mixture of minute solutions in a pl order droplet on a substrate by use of electrostatic force was developed. First, one of the solutions is pulled out of a nozzle utilizing electrostatic force, and forms a jet. The jet reaches a substrate, and an initial droplet is formed. Next, a jet of another solution is formed, and collides with the initial droplet. Thus, the interior of the mixture droplet is well stirred. The technique is also applicable to mixture of solutions with high viscosity. We demonstrated the experiment in mixture of rhodamine B solution and fluorescein solution. These dye components were dissolved in a medium composed of glycerine (50 %) and water (50 %), of which viscosity was ~20 times of water. The rhodamine B solution (0.67 pl) and the fluorescein solution (0.71 pl) were mixed, and mixture droplet (1.38 pl) was formed. Observing a fluorescence image of the droplet, It was confirmed that the solutions were mixed homogeneously.



Dielectrophoretic Droplet Formation and Fusion

Department of Mechanical Engineering, The University of Tokyo, Department of Electrical and Computer Engineering, University of Rochester       Masahide GUNIJI,

T.B.Jones and Masao Washizu

"We report dielectrophoretic (DEP) actuation of microliter sized aqueous liquid. The liquid, dispensed on co-planer electrodes structure, flows rapidly along the gap of the electrodes by DEP force when rf voltage is

applied. Nano-liter sized droplets formation is achieved using DEP liquid actuation and capillary instability. We demonstrate an on-chip micro liquid mixing device for combinatorial chemistry in which n kinds of samples and m kinds of reagents are first sub-divided into nano-liter volume using liquid DEP, and then electrically fused to obtain n x m product simultaneously."



Formation of Low Reflectance Surface by Using Electrostatic Flocking

Chiba Institute of Tecnology

Shunsuke TERASHIMA, Tsutomu ISAKA, Tomonao HAYASHI and Yasuo SEKII

In designing the equipments used in the space, the thermal design of apparatus is an important subject. Since the heat transfer in space is taken placed by radiation, the development of surfaces having absorptance similar to the black body is required. One of the promising methods of creating black body surface is a method of forming surface by electrostatic flocking. In the present research the possibility of forming black body surface by electrostatic flocking was investigated. Using an experimental set up having a pair of metal electrode with 5cm gap spacing, an experiment was performed applying 20kV DC voltage. The obtained carbon fiber-flocked surface was observed using scanning electron microscope, demonstrating that the electrostatic flocking is a feasible method of forming black body surface.



Development of Recovering Technique from the Micro-array by Using Laser Impulsion

Toyohashi Univ. of Technology

Shohei OSHIMA, Michihiko NAKANO, Kazunori TAKASHIMA, Shinji KATSURA and Akira MIZUNO

Recovering technique without using micropipettes or other conventional tools from micro-arrays was developed.  This technique employs laser impulsion phenomenon.  Applying a laser beam(YAG pulse laser, ƒΙ=1064nm, 800mJ) to the bottom of the well which is filled with DNA solution(pUC19 DNA contained) of the micro-arrays causes partial evaporation, and push out from the well.  As a result, damage of DNA in solution was not observed in this experiment. Because laser impulsion is occurred only a part of solution, and in a very short time, therefore it seemed that damage of double strands structure of DNA by heat or shock caused by laser impulsion is not occurred.



Electron Emission Properties of Carbon NanotubesSynthesized by Chemical Vapor Deposition

Dept. of Electronic Engineering, The University of Tokyo

Sunwoo LEE and Tetsuji ODA

Electron emission properties of multi-walled carbon nanotube (MWCNT) films synthesized by thermal hemical vapor deposition (CVD) method were studied. The diameter of synthesized carbon nanotubes (CNTs) are from 30 to 80 nm.  The size and the amount of CNT were strongly dependent on the size distribution of Ni catalyst particles which were deposited on the substrate surface.  It was found that the pre-process of the Ni deposited substrate was very effective in controlling the Ni-size distribution.  Those pre-processes are being dipped in hydro-fluoric solution or being exposed to ammonia gas.  As the electron emission test, a Ti metal electrode coated with CNTs was tested as the emitter (cathode) at 5L10 -5 Torr.  The average turn-on field is 4.6V/mm for 100mm gap between a CNT-coated cathode and a pure Ti anode.  The Fowler-Nordheim type current was recognized.



Preparation of ZnO Thin Film Varistor by sol-gel process and It's Electric Properties

Dept.of Electrical and Electronic Engineering, Akita Univ.

Tomoyuki WATANABE and Noboru YOSHIMURA

We have prepared ZnO-Pr6O11 coating thin film on an aluminum oxide substrate by sol-gel process using (CH3COO)2ZnE2H2O as the primary material, Pr6O11 as the doping agent. Then we measured the characteristics of ZnO-Pr6O11 based thin film varistor. ZnO-Pr6O11  based thin film varistor sintered at 1200Ž for 2 hours showed the varistor properties.



An Equivalent circuit for Zinc Oxide Varistors

Dept. of Electrical and Electronic Engineering, Akita Univ.

Mahmudul KABIR, Masafumi SUZUKI and Noboru YOSHIMURA

After sanding of some ZnO varistors' surfaces, we observed their internal structures by SEM. We measured the electrical capacity properties. The observed varistor voltage was 13.50[V] for the sample sintered at 1320Ž in air. Considering varistor's characteristics and measured electric properties; we made an equivalent circuit for the sample with a normal distribution value for the resistance of the grain boundary. The equivalent circuit was analyzed by PSpice Circuit Simulator.



Preparation of LSGM Films for Fuel Cells by Pulsed Laser Deposition(‡U)

Venture business Laboratory, Oita Univ.*, Faculty of Engineering, Oita Univ.**

Fumiaki MITSUGI*, Seiji KANAZAWA**, Toshikazu OHKUBO**, Yukiharu NOMOTO**, Tatsumi ISHIHARA** and Yusaku TAKITA**

Perovskite type (La,Sr)(Ga,Mg,Co)O3 has a potential for solid electrolyte of solide oxide fuel cell because of its high oxide ion conductivity. We prepared LSGMCO films on porous NiO anode electrode by pulsed laser deposition method. The film deposited at 800 degrees centigrade and 20 Pa oxygen atmosphere was poly-crystallized and had a structure of columns. The film showed higher electrical conductivity (< 1 Scm-1 at 800degrees) than that of the bulk.



Development of Electric Weeder with Discharge Device

Toyohashi Univ. of Technology

Makoto SUGIYAMA, Hiroshi YAHATA, Kazunori TAKASHIMA, Shinji KATSURA and Akira MIZUNO

Recently chemical methods of weeding using agrochemicals cause serious environmental pollution. Other methods, such as biological method using microorganisms, or physical method using a tractor and a burner have problems in environmental safety and weeding efficiency. So, safe and effective weeding method must be developed for agriculture. In this study, the authors have tested three types of electric weeder equipped with high voltage discharge device and a rotating weed cuter. As a result of the long-term field test, high capacity high voltage transformer was most effective to annihilate the weeds.



Reaction mechanism of Na2CO3 particle with SO2 on electrodynamic balance

Faculty of Engineering, Gunma University


The microreactor, which was combined with EDB (Electrodynamic Balance) and Raman spectroscopy, is useful for understanding the interaction of pollutants with the fine particles in the atmosphere or pollution control technologies. The Na2CO3 microparticle was captured into EDB which consists of two cylinder type electrodes for DC voltage and outer cylindrical electrode for AC high voltage. The desulfurization reaction mechanism of Na2CO3 suspended particle with SO2 in which was controlled the humidity was examined from weight change of particle, its morphological change and Raman spectra. The morphology of an aggregate Na2CO3 particle changed to a sphere because phase variation from solid to liquid by absorbed hygroscopic moisture. The spherical droplet was exposed into 1% SO2 gas into EDB and the Na2S2O5 particle as reaction product was observed from Raman spectra. It is possible to establish the experimental method in which we can trace the reaction of single fine particle with gasous species trace.



Fundamental Characteristics of Positive Corona Discharge in Needle-to-Plane Electrode System(‡U)

Department of Electrical and Electronic Engineering, Oita Univ.*, Institute of Fluid Flow Machinery, Polish Academy of Sciences**

Seishu SHIMAMOTO*, Katsuhisa TAKASE*, Seiji Kanazawa*, Toshikazu OHKUBO*, Yukiharu NOMOTO* and Jerzy Mizeraczyk**

In this study, fundamental characteristics of dc positive needle-to-plane corona discharge were investigated. Glow-mode and streamer-mode discharge were produced separately by changing the needle electrodes. As a result, the current distribution of glow discharge was in good agreement with the empirical Warburg law. However, the current distribution of streamer discharge was sharper and narrower than that of glow discharge. For a fixed total current, the centerline current density of streamer discharge was high compared to that of glow discharge.



Effect of the material of electrode on the discharge in short air gap

Tokyo Unv. of Science        Tatsutoshi SHINJO and Noriaki MASUI

This paper describes the dependence of spark gap length and peak current on the materials of electrode. Spherical electrodes of brass, copper and aluminum are used.  The diameter of each electrode is 20mm. The electrode surface is polished using polishing powder of 0.05 ƒΚm mean particle size. The earth electrode approaches high voltage electrode at 0.4mm/sec speed, and the electric charge charged in the ceramic capacitor of 100pF at +6kV is discharged.  The material of electrode affects the dispersion of spark gap length.  Peak current decreases with increase in the spark gap length. When the voltage applied to the electrode is constant, peak current and waveform of discharge current are only depend on the spark gap length.



Electric Currents with Multiple Peaks for Electrostatic Discharge Occurring between a Charged Metal Plate and a Grounded Electrode

Yamagata Univ.


A current waveform of the electrostatic discharge occurring between a charged metal plate and a grounded electrode has been investigated focusing on the appearance of multiple peaks on the discharge current.  The grounded sphere electrode of 18.6 mm in diameter was approached close to the square charging plate ranging from 0.1 m to 0.6 m in side charged up to 15 kV.  It was found that the electrostatic discharge current include not only a single peak, but also double peaks or multiple peaks depending on the polarity, charging voltage and the size of the charged conductive plate.  For positively charged plate larger than 0.4 m in side length the discharge currents have double or multiple-peaks.



The Effect of the Droplet Quantity on AC Corona Discharge from the Water Droplet

Department of Electrical and Electronic Engineering, Kanagawa Institute of Technology

Kotaro SUZUKI and Hirofumi SHIMOKAWA

AC corona discharge which arose from the tip of pendent water droplet was studied. The corona discharge was generated between the plate electrode and the water droplet.  As AC voltage applied to plate electrode, multiple electric discharge was observed from the water droplet tip in the positive cycle. Positive corona electric discharge was observed in the negative cycle. The electric discharge which arose in each cycle resembles electric discharge which arose as D.C. application. Therefore, AC corona discharge is seemed to alternately generate the D.C. corona discharge. It was found that the corona discharge is dependent on the water droplet quantity and the frequency of applied voltage.



Effect of the skin resistance of fingertip on the discharge from human body (‡U).

Tokyo Unv. of Science

Tadafumi KATAOKA and Noriaki MASUI

In this paper, the result of examining the relation between discharge current waveform from the human body and type of discharge pattern on the fingertip is described. The human body is charged up to }4kV. @In case of the negative discharge, there are two peaks in discharge current, and the second peak is higher than the first one.  For the case of positive discharge, only one peak appears in discharge current.  For negatively and positively charged human body, two types of discharge pattern appears on the fingertip.  The change of electricdischarge pattern that appears on the fingertip seems to be correspondent to the change in the waveform of discharge current.



AC Breakdown Characteristics via a Water Droplet Placed on a Hydrophobic Sheet

Yamagata Univ.

Yoshio HIGASHIYAMA, Toshiyuki YAMASA, Toshiyuki SUGIMOTO and Takeichiro TAKASA

Deformation of a water droplet on a hydrophobic sheet and breakdown voltage via the droplet under an ac electric field have been investigated experimentally.  A droplet of pure water, 3% saline solution or 5% ethanol solution was located on a silicone rubber sheet or a PTFE sheet to evaluate the effect of conductivity and surface tension of water on the deformation of the droplet due to the electric field. The deformation of the droplet strongly depends on the frequency of applied voltage. As a result, the breakdown voltage via the droplet under the ac electric field at resonant frequency was significantly decreased.  The breakdown voltage via the droplet on the PTFE sheet was lower than that on the SR sheet because of the surface property that allowed the droplet slide.



Basic Research on Disk Type Corona Motors (‡Z)

Sendai National College of Technology*, Shishido Electrostatic, Ltd.**    

Masayuki HATTORI*, Yamato SEKI*, Yuichi RINGO* and Kenkichi IZUMI**

In our previous report, a disk-type corona motor using CD (Compact Disk) type of rotor consisting of two glued CDs was made and tested for the purpose of extension to a multi-disk-type corona motor instead of the former type of rotor (pcb rotor). Although with the CD-type rotor one can work more efficiently, it is difficult to narrow the air-gap between the rotor and the stator (discharging electrodes) of the corona motor because this CD-type rotor is distorted by being glued. Therefore, we adopted a DVD (Digital Video Disk) type of rotor, both of whose sides are usable without gluing, and compared its various characteristics with the CD-type rotor. Because adjustment of the air-gap length of the DVD-type rotor is easier than the CD-type one, the generating torque characteristic of the DVD-type corona motor has good linearity for incrementally applied voltage.  Also, it was confirmed that the DVD-type of rotor is suitable for the multi-disk type corona motor because there is less distortion of the disk.



Development of Ion Conveying Type Ionization System -Generation of Large Charged Particles by Ultrasonic/electrostatic Atomization-        

Tech. R&D Center, Techno Ryowa Ltd

Masanori SUZUKI, Tomokatsu SATO, Takeshi EBINE and Akio SUGITA

In recent years, we have conducted the development of ionization system@conveying  ions  through  tubes,  in order to control static electricity in@narrow space such as space in ULSI and LCD manufacturing equipments.@ In  previous  paper, we reported the results of evaluation in terms of the@influence   of   several  factors  on  charge  eliminating  performance  of@ionization  system  generating charged fine mists (large charged particles)@by  electrostatic  atomization.  However,  its  ionization system could not@generate  charged  fine  mists stably in closed narrow space. Therefore, we@have  developed  new  ionization  system  generating  charged fine mists by@ultrasonic / electrostatic atomization.@ In  this  paper,  we will report the results of evaluation in terms of the@influence  of several factors on charge eliminating performance of this newionization system.



Charge Elimination Characteristic and Ozone Generation Characteristic of the Dual Jet Ionizer

Ibaraki Univ.*, The Polytechnic Univ.**

Hiroyuki IMAZONO*, Manabu TAKEUCHI* and Kazuo OKANO**

The dual jet ionizer was proposed in order to reduce the contamination from the ionizer. The dual jet ionizer is made up of nozzles and jet emitters located at the center of the nozzles. Both the jet emitter and the nozzle can spray argon gas. In this report, we deal with ozone concentration of the dual jet ionizer as a function of inner jet flow rate and outer jet flow rate. The ozone concentration depended strongly on the inner jet flow rate and outer jet flow rate.



Influence of Distance between Emitter Tip and Control Grid on Noise Characteristic of Low Noise Air Ionizer

The Polytechnic University

Dogo OHASHI and Kazuo OKANO

The low noise air ionizer that has an upward emitter, a grounded grid above the emitter and a grounded electrode below the emitter was proposed to utilize in an inspection process of ULSI devices. The output voltage of electrostatic induction sensor (VO_P-P) as noise characteristic and the average discharge speed (dVPA/dt) as charge elimination characteristic were measured. These characteristics depended strongly on the distance between the emitter tip and the grounded grid (L). The ratio of VO_P-P to dVPA/dt (dVPA/dt/VO_P-P) was highest value at L = 50 mm.



Effect of Emitter Voltage on Discharge Speed and Ozone Density

The Polytechnic University

Satoshi KUSAKARI and Kazuo OKANO

The use of a corona discharge air ionizer is one of the effective methods to control the electrostatic charge in an LCD and an OELD in the manufacturing process. However, the air ionizer generates a small amount of ozone that cause degradation of emitter tip and changing of the thickness of oxside-film grown on the silicon wafer. In this report, we investigate the effect of the emitter voltage on the discharge speed and the ozone density. The discharge speed and the ozone density was controlled by the emitter voltage of the air ionizer.



Electrostatic atomization of water and its application to generation of ionic space

Tokyo Univ. of Science 


The characteristics of electrostatic atomization were investigated.  The atomized fine water droplets are highly charged and charge elimination experiment was carried out using the charged droplets from the atomizer.  The charged atomized water droplets dry as they left the atomizer and the space around the atomizer was ionized.  It has good ability for eliminating the charged body 2m apart from the atomizer.



 The Characteristics of Electrostatic Discharge from Conductive Fibers

Tokyo Univ. of Science*, Daiwa Co. Ltd.** 

Hirofumi INOUE*, Changrag CHOI*, Yuji MURATA* and Kohei YAMADA** 

The characteristics of corona discharge and those of electrostatic discharge from various conductive fibers were investigated in order to find the suitable fibers for eliminating the electrostatic charge. From the results obtained, it was found that the discharge distance from the charged body depends on the diameter of the fiber and the relation was expressed by the formula y = Ax|B, where A and B are constants, y the discharge distance between the fiber tip and the charged body, x the diameter of the fiber.



Measurement of Static-charge during the Production of Firework-explosive

National Institute of Industrial Safety


For the prevention of accidental explosions in firework factories, static-charges during the manipulation of powder materials were experimentally investigated. Aluminum, Sulfur, Potassium-perchlorate were selected, and were sieved with  steel mesh and horse mesh, transferred from one container to another. The human body during the sieving of aluminum power of 2 kg with horse mesh reached over 15 kV. Sulfur obtained charge over 20 micro-C/kg with either mesh. Even aluminum as well as aluminum-sulfur mixture obtained nearly 1 micro-C/kg of static-charge. Since some firework-explosive can be ignited by a spark of several milli-joules, strict preventive measures should be taken in this kind of industries.



Glow Discharge Neutralizer

National Institute of Industrial Safety

Atsushi OSAWA 

A charge neutralizer using glow discharge in air at atmospheric pressure has been developed.  A fairly stable glow discharge without any instabilities, such as low-to-arc transition, could be produced in air at atmospheric pressureby using ac excitation and a micro cone-hollow electrode.  Theglow discharge has been applied to a charge neutralizer (ionizer) and its performance has been investigated experimentally. Consequently we found that the charge neutralizer has a reatly good performance in ion balance.  Furthermore dc bias in source voltage could control ion balance precisely.



Charge Elimination Performance of Nozzle-type Eliminator for Powder-Effect of Waveform and Frequency of Applied AC Voltage-

Kasuga Denki INC*, National Institute of Industrial Safety, Independent@Administrative Institution**, Dept. Chem. Eng., Osaka Pre. Univ.***

Teruo SUZUKI*, Tomohumi MOGAMI*, Tsutomu KODAMA** and Satoru WATANO***

For improvement of the nozzle-type electrostatic eliminator for powder handling the effect of waveform and frequency of the applied AC voltage to the eliminator on the static charge elimination performance was studied using a full sized experimental facility for pneumatic PP pellets transportation including a silo. As a result, the square wave had higher static charge reduction ability than the sinusoidal wave in the frequency region 10-200Hz. The charge reduction ability increased with the increase of the frequency but showed a tendency toward reverse charging saturating to the magnitudes depending on the applied voltages when the frequency was increased further for the both waves. The optimum frequency for the sinusoidal wave was approximate 70Hz when the applied voltage was 7kV.



Generation of ionic space using atomized water droplets charged by corona discharge

Tokyo Univ. of Science

Atushi Yokoyama and Yuji Murata

For the purpose of elimination of the electrostatic charge, charged fine water droplets were generated using a corona discharger and a dry fog nozzle. In the present experiment, in order to improve the charge-eliminating characteristics, the electrode system for corona discharge was improved. In the case of 4 needle electrodes, the space charge density becomes 6 times as large as that in the case of single needle electrode.



Pulsed discharge plasma in water using multi nozzle system with air bubbling

Department of Biological and Chemical Engineering, Gunma University

Anto Tri Sugiarto, Masayuki Sato

The pulsed discharge plasma in water with air bubbling has been investigated for degradation of organic compounds in water.  The reactor with multi hollow needle to plane electrode system was used in this experiment.  It was found that the formation of plasma channel was greatly influenced by the flow rate of air and the applied pulsed voltage.  The plasma channel became strong and longer with increasing flow rate, and became more brushy when the applied pulse voltage was increased.  Therefore, the degradation rate was high when the flow rate and the applied pulsed voltage were increased.  Furthermore, the degradation rate was independent of the water conductivity.



Decolorize Reaction of Indigo Carmine by Pulsed High Voltage

Toyohashi Univ. of Technology


Various radicals, generated by discharge plasma, play important roles as oxidant in chemical reaction. Decolorize reaction of indigo carmine (C16H8N2Na2O8S2) by pulsed discharge plasma over liquid surface in low-pressure conditions (25-100Torr)@and lectrolysis were studied. Hydrogen peroxide (H2O2) was generated after the experiment. Indigo carmine can be decolorized by H2O2, but it was very slow in this experimental condition. The decolorization by the discharge over liquid surface was more effective than electrolysis and H2O2. As a result, the decolorization depended on mainly UV and radicals and not depended on electrolysis and H2O2.



Dependence of Diameter of Droplets on Treatment Rate of Watste Water Using Water Droplets by Pulsed Power Discharge

Yamagata Univ.     Yasushi MINAMITANI, Toshitaka SATO and Yoshio HIGASHIYAMA

Since non-thermal plasma is able to produce high-energy electrons, free radicals and UV having high chemical reactions, stilliform water into the plasma can be expected high treatment in the water remediation. The experiment for water treatment was carried out by injecting water droplets into the non-thermal plasma generated in air by pulsed power. The used sample is 0.1% water solution of sodium dedecylbenzensulfonate (C12-LAS). The repetition rate of pulsed discharge and the transit time of water droplet were set as ea‚ƒ‚ˆ water droplet exposes to the discharge once. As the diameter of droplets increases, the degradation rate of C12-LAS is increased.



Decoloration of dye by a combination of pulsed streamer corona discharge and electrostatic atomization

Department of Biological and Chemical Engineering, Gunma University

Ellyana Njatawidjaja, Anto Tri Sugiarto, Takayuki Ohshima, Masayuki Sato

Fine droplets of aqueous dye solution were introduced into pulsed streamer corona discharge region for decoloration of dyes. The droplets were produced electrostatically into small size and were processed by active species that were generated by streamer corona discharge in air. Chicago sky blue solution was decolorized more than 90% within 30 minutes using this system. The decoloration efficiency was depended on the applied pulse voltage, atomization voltage and air flow rate.



Water Treatment Using Bubble Assisted Pulsed Discharge Plasma

Toyohashi Univ. of Technology


Water treatment using pulsed discharge plasma was examined in this study. Pulsed@discharge occurres efficiently by bubbling solution. In this paper the decolorization of dye using various gap of electrode and bubbling gas (Ar, Air, O2) were investigated. As the result, decolorization of dye was enhanced by the bubbling. The most efficient electrode gap and bubbling gas were 25mm and O2 respectively.

30aB6    Features of a Compact Foaming Reactor        Features of a Compact Foaming Reactor        Saga Univ.*, Toyohashi Univ. of Technology**, Prywatna Wyzsza Szkola Ochrony Srodowiska***          ›Joanna Pawlat*, Akira Mizuno**, Chobei Yamabe*, and Iwo Pollo***            This paper reports a new method of oxidants generation by the electrical discharge in dynamic foam, which was formed without surfactant s addition. Several electrode set-ups were tested in the foaming column. Performed measurements confirmed the presence of oxidants in foam and in post reaction gas and liquid. OH radicals were generated. The highest concentrations of gaseous ozone (875 ppm), dissolved ozone (0.5 mg/dm3) and hydrogen peroxide (62 mg/dm3) were obtained in oxygen using a needle-to-alumina dielectric covered plate electrode at 14 kV of applied voltage and 5 dm3/min of substrate gas flow.



The Influence of Water on Gas Phase Anions

Dept. of Chemical System Engineering, University of Tokyo

Takamasa SETA, Masateru NISHIOKA, Quanxin Li and Masayoshi SADAKATA

In order to investigate the influence of water on the gas phase anions at atmospheric pressure, the equilibrium calculations and the Monte Carlo Simulation (MCS) has been developed. The results of equilibrium calculations indicate that the number of water for Ox-(H2O)n have an upper limit. The pulsed corona discharge at atmospheric pressure was simulated by the MCS applying 50 molecules and 733 elemental reactions. When water is present in the atmosphere, the gas phase oxygen anions change to Ox-(H2O)n even at 1-10 us after the pulsed discharge is off.



Decrease of Discharge Current and OH Production by a Small Amount of Trichloroethylene in a Pulsed Corona Discharge              Department of Electronic Engineering,

School of Engineering, the University of Tokyo

Ryo ONO and Tetsuji ODA

OH formation in a pulsed corona discharge is greatly decreased by a factor of 10 when about 300 ppm of trichloroethylene (TCE) is added to the ambient gas, while that decrease is not observed in a pulsed dielectric barrier discharge (DBD). Our experimental results show that it is due to the reduction in discharge current by the addition of TCE. The corona and DBD currents consist of "charging current" which charges electrodes, and "discharge current" which corresponds to the flow of electrons/ions between electrodes. It is shown that OH is formed by the discharge current, not by the charging current. The discharge current is decreased by a factor of 10 when about 300 ppm of TCE is added. That leads to the decrease in OH production. The contribution of OH to the decomposition of TCE is studied. The decay rate of OH is changed little when the TCE concentration increases from 0 ppm to 300 ppm. Besides the TCE decomposition ratio is approximately constant at the H2O concentration of 0-2\%. Those results show that the OH is not responsible for the TCE decomposition.



Caracteristics of excited molecule density and vibrational temperature for nitrogen non-thermal plasma in a ferro-electric packed bed reactor

McMaster Univ.*, Iwate Univ.**

Yoshihisa UCHIDA*, Kuniko URASHIMA, Koichi TAKAKI*,** and Jen-Shih CHANG*

Base on the spectroscopic measurements, the number density of the excited nitrogen molecules have been investigated for nitrogen non-thermal plasma in a packed bed barrier discharge plasma reactor. In a ferro-electric packed bed reactor, the ferro-electric pellets enhance the electric fields in the contact regions between adjacent pellets and lead to micro breakdowns in the gaps, producing high energy free electrons. These electrons are used to dissociate and ionize the carrier gas molecules in which the pollutants are present to produce radical. The radicals and electrons are then treat pollutants in flue gases. Experiments were conducted for applied voltage from 0 to 20kV, operating frequency 60 Hz and gas flow rate from 1 to 5 LPM under pure nitrogen gas. The results shows that the number of density for excited N2 molecules from model increases with increasing applied voltage and dielectric constant and agree qualitatively well with the experimental results at lower applied voltage. The vibrational temperature of the C3Pu(v') state of N2 have been determined from optical intensity emitted by 2nd positive band. The 1800 to 2400 K vibrational temperatures were observed.



Observation of OH and Ozone in a Pulsed Corona Discharge Plasma

Department of Electronic Engineering, School of Engineering, the University of Tokyo

Ryo ONO and Tetsuji ODA

OH radical and ozone are observed in a pulsed corona discharge plasma. The OH is observed by laser induced fluorescence (LIF) method, and the ozone is observed by laser absorption method. In both measurements, a tunable KrF excimer laser is used. The discharge is occurred in a 0.25-L reactor with multiple needles--plate electrode. After the discharge pulse, the ozone is produced with a time constant of about 20 us in dry air. The time constant approximately equals to that calculated from a referred reaction rate of O + O2 -> O3. The ozone concentration increases up to 1500 ppm for 100 us after discharge. It is observed that the ozone yield decreases by a factor of about 10 when H2O concentration increases from 0\% to 2\%. That can be caused by (i) decrease in O radical or (ii) reaction of O3 + OH. To observe the reaction of ozone with OH, OH concentration is measured in an environment with or without O2. In the present study, however, the reaction can not be definitely observed.



Characteristics of Ozone Generation by Negative Corona Discharges in Mixture Gases of O2 and N2 at Atmospheric Pressure

Daido Institute of Technology

Daisuke ISHIJIMA, Akira GOSHIMA, Yuuto SAWAKI, Keiichirou SUGITA and Yoshihisa SEKIYA

 For the application to a small and simple ozone generator, we are investigated the characteristics of ozone generation by positive and negative point-to-plane corona discharges in room air and mixture gases of O2 and N2 at atmospheric pressure. It is well known that the efficiency of ozone generation by negative point-to-plane corona discharge in room air at atmospheric pressure is around 120g/kWh and that of in pure oxygen gas is around 240g/kWh. Although the number of oxygen molecule in pure oxygen gas is 5 times of that in room air, but ozone efficiency in pure oxygen gas is only 2 times of that in room air. In this paper, we investigated to clear for that cause on the basis of the characteristics of ozone generation by negative corona discharges in mixture gases of O2 and N2 at atmospheric pressure.



Gas Flow Effect on Discharge Characteristics of a Non-thermal Plasma

*Institute of Fluid Science, Tohoku University@**Graduate school of Engineering, Tohoku University

Takehiko SATO*, Makoto Kambe** and Hideya Nishiyama*

The characteristics of high voltage discharges in the gas flow at atmospheric pressure have been investigated experimentally. The breakdown voltages for the different gap lengths of the parallel plate electrodes are measured with applied voltage rising rate, applied waveform, applied wave frequency, gas flow rate and kind of gas. The effect of pd, which is the product of the pressure and the gap length, on the breakdown voltage corresponds to Penningfs experimental data for the applied voltage rising rates from 0.1 kV/s to 10 kV/s. However, they are not in accordance with the data when the rates are more than 100 kV/s. On the other hand, the breakdown voltage for the different waveforms such as sawtooth, sinusoidal and square and also for the different wave frequencies of 100 Hz, 1 kHz and 10 kHz corresponds to the experimental data reported by Penning, Kind and Karner. The breakdown voltages show the minimum values when the gas flow rates are 2 - 4 Sl/min for argon gas. The gas flow rate also affects the discharge current mode which is classified to two modes.


30pB7    Particle Velocity Field in Electrostatic Precipitator Model – PIV Experiment

Particle Velocity Field in Electrostatic Precipitator Model – PIV Experiment* Centre for Plasma and Laser Engineering, Institute of Fluid Flow Machinery, Polish Academy of Sciences,@** Dept. of Electrical and Electronic Engineering, Oita University

Jerzy MIZERACZYK*, Marek KOCIK*, Jarosław DEKOWSKI*, Janusz PODLIŃSKI* Seiji** KANAZAWA and Toshikazu OHKUBO**

There is still an interest in improving electrostatic precipitator (ESP) collection of fine particles (micron and submicron sizes). However, it is not yet clear whether the turbulent flow patterns caused by the presence of electric field and charge in ESPs advance or deteriorate fine particle precipitation process. In this paper results of the Particle Image Velocimetry (PIV) measurements of the particle flow velocity field in a wire-to-plate type ESP model with seven wire electrodes are presented. The measurements were carried out for negative and positive polarity of the wire electrode. The PIV measurements clearly confirmed formation of the secondary flow (velocity of several tens of cm/s) in the ESP model, which interacts with the primary flow. The particle flow pattern changes caused by the strong interaction between the primary and secondary flows are more pronounced for higher operating voltage (higher electrohydrodynamic number NEHD) and lower primary flow velocity (lower Reynolds number Re). The particle flow patterns for the positive voltage polarity of the wire electrodes are more stable and regular than those for the negative one due to the nonuniformity of the negative corona along the wire (tufts).



Collection of Uni-pole Charged Particles with AC Electric Field  

Elect. Appl. Lab., Musashi Institute of Technology*, Fuji Electric Co.,Ltd.

Yoshihiro KAWADA*, Takafumi KUBO*, Yoshiyasu EHARA*, Takeo TAKAHASHI*, Tairo ITO*, Akinori ZUKERAN**,Yoshihiro KONO**, and Kouji YASUMOTO**

Electrostatic Precipitators (ESPs) are used extensively for environmental preservation, since this technique shows high precipitation efficiency and a low pressure drop. One of the major tasks of Two-Stage ESP applications is to increase visibility and to clean the air in the superhighway tunnels. However, the collection efficiency for large particles decreases due to the particle re-entrainment phenomena. The re-entrainment phenomena are caused by agglomerated particles on the collecting electrode due to the low resistively of the particles. The finding re-entrainment process and restraining re-entrainment phenomena were investigated. In this work, we discussed the method preventing particle re-entrainment, and devised applying rectangular AC high voltage to the collecting electrodes. When AC high voltage applied collecting section, pearl-chain like agglomerated particles are not observed compared with at DC high voltage applied. Collection efficiency with particle weigh calculation at DC applied almost equal to that at rectangular AC applied. However, when rectangular AC high voltage applied, the collection efficiency of large particles improved. It has been shown that the re-entrainment phenomena are prevented on applying rectangular AC high voltage.



Numerical Simulation of Three-Dimensional Point/Tuft Corona and Electrohydrodynamics

Dept. Energy Systems Eng., Osaka Pref. Univ.             

Toshiaki YAMAMOTO, Miyuki OKUDA and Masaaki OKUBO

The industrial electrostatic precipitators (ESPs) employ negative corona or point corona, which generates discrete discharge along the wire electrodes. Three-dimensional analysis of electrical characteristics and electrohydrodynamics is essential to describe the ESPs having tufts/point coronas. The distribution of the secondary flow (electric wind) is to form a donuts-shape ring from each tuft/point, extending further to the inflow and outflow direction. When the primary flow exits, the flow interaction takes place, depending upon EHD number which is defined as the ratio of EHD Reynolds number to ordinary Reynolds number or simply, the ratio of characteristic electric wind velocity to the primary flow velocity. The electrohydrodynamic flow field is to form a pair of spiral vortex rings, like Goertler vortices in the direction of the gas flow. The effects of electrohydrodynamics on particle motion and ESP theory were discussed.



Scrubbing Dust Collector Combining Electrostatic Precipitator

Nihon Univ.

Tomoo NAKANE, Takeshi MIYAJIMA and Tetsuro OTSUKA

An aerosol processing was conducted in water using a vortex flowchurning system, however, it was not capable of perfectly removing flue gas. The flue gas was@therefore collected by an Electrostatic@Precipitator (EP) after the aerosol processing. As a result, it is@possible to completely collect the flue gas by using the aerosol@processing together with the EP. In this present, an experimental@production of the EP is introduced, and its performance also@estimated.



Electrostatic Precipitation and Oxidation of DEP Using Discharge on the Pt Catalyst

Toyohashi Univ. of Technology

Yoshihiko MATSUI, Satoshi SATOH, Kazunori TAKASHIMA, Shinji KATSURA and Akira MIZUNO

In this study, packed bed plasma reactor was investigated for the diesel exhaust emission control. We tried two experiments, one was the particle collection test and the other was the oxidation test of DEP using the packed bed (Pt-Catalyst) plasma reactor. In the particle collection test, ambient air and diesel exhaust were used as test gas. Removal efficiency of about 94% was obtained for particles larger than 0.3mm diameter in the@ambient air. On the other hand, in the diesel engine exhaust test, the SEM observation of the collected particles showed that particles of several hundred nanometer size were successfully collected the plasma reactor. In the DEP oxidation experiment, the most effective oxidation temperature was 100C using Pt-catalyst with discharge.



Selective Fixation of Modified DNA Molocules on a Hydrophobic Substate

Toyohashi Univ. of Technology

Shun-ichi MATSUURA, Hirofumi KURITA Michihiko NAKANO, Jun KOMATSU, Kazunori TAKASHIMA Shinji KSATSURA and Akira MIZUNO

We demonstrate an effective method for DNA immobilization on a hydrophobic glass surface. The new DNA immobilizing technique is extremely simple compared with conventional techniques that require heterobifunctional crosslinking reagents between DNA and substrate surface@that are both modified chemically. In the first process, a coverslip was treated with dichlorodimethylsilane resulting in hydrophobic surface. Lambda DNA molecules were ligated with 3'-terminus disulfide-modified 14 mer oligonucleotides at one cohesive end, and then reacted on silanized coverslip followed by the reduction of disulfide to sulfhydryl group (thiol). Fluorescent observation showed that the thiol-modified lambda DNA molecules were anchored specifically to the surface at one terminus, although non-specific binding of the DNA molecules was suppressed. It was observed that the one-end-attached DNA molecule was bound firmly to the surface and stretched reversibly in one direction when a d.c. electric field was applied.



Addition of an Adapter to the Physically Dissected DNA Fragment

BRAIN(Seiken-Kiko), Advance Co., Tokyo University

Osamu KUROSAWA, Hiroyuki KABATA and Masao WASHIZU

The authors have proposed a novel DNA analysis method based on physical molecular manipulation. A fluorescent labeled DNA is stretch-and-immobilized on the substrate and arbitrary region of DNA is physically dissected using AFM stylus under the fluorescence microscope. Then dissected fragments are recovered to be analyzed the sequence. According to this method, the complicated work of the reconstruction, which is necessary for the case of shotgun strategy, can be reduced, because the position of DNA fragment on original DNA is known. It is experimentally shown that thousands of dissected fragments without molecular damage can be recovered. However, it is not possible to do the sequencing in the number of the thousands molecule, so they must be once amplified by PCR. If an adapter sequence is added to the both ends of the dissected fragments, the fragments can be PCR amplified making use of the adapter sequence. A problem here is how to add the adapter to the molecular damaged terminus brought about by the physical dissection. In this paper, recovered dissected fragments are enzymatically treated with a T4DNApolymerase, and then linked to the adapter. Three kinds of primers are prepared: One corresponding to the sequence near one end of ƒΙDNA(L1), one to the other end of ƒΙDNA(R1), and one to the adapter(T7). Using these primers, ligation samples are PCR amplified. If the adapter ligation is successfully done, the PCR result should contain the fragments amplified between L1 and T7, between R1 and T7 and between T7 and T7. The experimental result shows that only the fragments between T7 and T7 is not amplified within above three fragments. It means that T4DNApolymerase single treatment is not sufficient to repair the physically damaged terminus.



DNA-Protein Complexes Analysis by Atomic Force Microscope

Toyohashi Univ. of Technology


We have been studying micromanipulation technique of single molecule DNA for rapid genome analysis. We have studied to detect specific sites in DNA molecules such as mismatched base pairs by atomic force microscope (AFM). We can determine the mismatch position precisely and rapidly if we can observe a protein that specifically binds to a mismatch point on a stretched DNA molecule. In this study, we tried to observe restriction enzyme-DNA complexes as a model of protein bound mismatch point on stretched DNA molecules. We immobilized DNA molecules in stretched form using several techniques. And we clearly observed the restriction enzyme attached to a specific site of DNA molecule.



The Fundamental Study for Successive Digestion and Recovering Method of DNA

Toyohashi Univ. of Technology

Michihiko NAKANO, Jun KOMATSU, Shun-ichi MATSUURA, Kazunori TAKASHIMA, Hachiro YASUDA, Shinji KATSURA and Akira MIZUNO

"We have developed a novel DNA analysis method using single molecule DNA. It consists of five unit operation as follows; (1) stretching single molecule DNA, (2) cutting in order from a terminus, (3) recovering its fragments, (4) PCR (Polymerase Chain Reaction) amplification, (5) sequencing.  We considered that this method did not require the rearrangement of the fragments, which is indispensable and laborious in shotgun method. Many studies have been carried out for DNA fixation on a glass substrate with stretched shape.  However, it is difficult to recover fragments in this method where DNA molecules are fixed on a glass substrate. We developed a method to stretch DNA without fixing on a glass substrate. We used electrostatic field. A DNA associated with restriction enzyme, Mg2+ completely chelated to suppress the activity, was stretched in agarose gel under the electrostatic field. Then MgCl2 was added to the cathode and Mg2+ moved toward to anode.  When Mg2+ encountered the restriction enzyme, the enzyme was activated to cut DNA.  And the fragment was carried toward cathode by electrophoretic force.



Fundamental Study on Successive Ionization Method of a DNA Molocule for Novel Ultra High-speed Genome Analysis

Toyohashi Univ. of Technology

Takuya FURUMAKI, Michihiko NAKANO, Tadashi KURODA, Jun KOMATSU, Shunichi MATSUURA, Kazunori TAKASHIMA, Hironaga UCHIDA, Shinji KATSURA and Akira MIZUNO

We studied an application of FIM (field ion microscope) to DNA sequencing. By applying a DC voltage to the FIM tip on which a DNA molecule is attached, the base may be released and fly along the electric force field. Ultra high-speed genome analysis will be feasible by detecting the digested bases. At first, we examined whether DNA molecule can be observed with FIM. DNA molecules with SH group prepared by PCR (polymerase chain reaction) were attached on the needle tip of an electro-polished gold (Au) and tungsten (W) wire. Fluorescent observation of attached DNA molecules showed Au wire was preferable for FIM observation because of its high stability. A weak FIM image was observed when the applied voltage was very small, suggesting the attachment of DNA molecules. The image became brighter and changed its shape with further increase in applied voltage. However, no apparent image was observed when the same sample was observed at the low applied voltage where the faint image had been observed. These results suggest that the attached DNA molecules were detached during the first run.



Development of Visualization Method for Single-stranded DNA

Toyohashi Univ. of Technology*, Kove-Gakuin Univ.**, Science Univ. of Tokyo***

Satoshi UEHARA*, Hiroshi NAITO*, Shun-ichi MATSUURA*, Keiichi TAKATA***, Yoshiyuki MIZUSHINA**, Kengo SAKAGUCHI**, Shinji KATSURA* and Akira MIZUNO*

"Single molecule observation have elucidated several phenomena for biopolymers such as DNA, RNA and proteins in cells.@In this study, we paid attention to observe DNA synthetic system. For this purpose, fluorescent labeling of single-stranded DNA molecule is required, however, conventional methods, such as intercalating dyes, cannot visualize a single-stranded DNA.  We developed an observation technique based on fluorescent labeled RPA (replication protein A), which was eukaryotic single-stranded DNA-binding protein (SSB).  We also developed other methods for a single DNA molecule visualization. One was based on enzymatic incorporation with a fluorescent labeled nucleotide, and the other was based on reaction with

fluorescent labeling reagent. These methods permit visualization of individual ƒΙ DNA molecules.



Electrostatics sensitivity of B/KNO3 granular igniter composition

National Inst.of Advanced Industrial Sci.and Tech.* Nikko Gika Co., Ltd.**, Fac,of Eng, Kyushu Sangyo Univ.***      

Eishi KURODA*, Masatake YOSHIDA*, and Toshiyuki NAGAISHI***

Electrostatic sensitivity test was carried out with the fixed gap method and the approaching electrode method for B/KNO3 granular igniter composition and its grinded powder. The minimum energies of 50% ignition probability were 101mJ with the fixed gap method and 20.6mJ with the approaching electrode method.. The  capacitancies with the minimum energy of 50% ignition probability were 4nF by the fixed gap method and over 28.2nF by the approaching electrode one, respectively.  The apparent time constant obtained by the approaching electrode apparatus was 1ms and independent of the capacitance. These are the same as those obtained by the fixed gap method tested under the capacitance of 6nF.  It is suggested that the apparent time constant and the minimum capacitance for ignition are important factors to estimate the electrostatic ignitability. It is concluded that the electrostatic ignitability is not higher for B/KNO3 tested in this experiment, irrespective of the minimum ignition energy.



Ignition test of titanium powders by the probe plate method

National Inst.of Advanced Industrial Sci.and Tech.* Nikko Gika Co., Ltd.**, Fac,of Eng, Kyushu Sangyo Univ.***

Eishi KURODA*, Masatake YOSHIDA*, Hiroshi NARASAKI** and Toshiyuki NAGAISHI***

The probe plate method is to test whether a sample was ignited or not when it is rubbed on the metal plate with the metal probe under the applied voltage. The method was adopted at first in 1968 to investigate how the lead azide explosion occurred.  It is one kind of the ignition tests by electrostatic discharges.  In this report, the ignition test of titanium powders was carried out by the probe plate method.  It is observed that titanium powders were easy to ignite with very low energy under the small capacitance. It is suggested that titanium powders are very hazardous against electrostatic discharges, if any metal tools are used.



Ignitability Assessent of Dusts in Shredding Process for Discarded Electrical Appliances

Research Center for Explosion Safety, National Institute of Advanced Industrial Science and Technology

Masaharu NIFUKU, Julien GATINEAU and Hiromi KATOH

Enforcing the recycling of electrical appliances (refrigerator, air@conditioner, television set and ashing machine), a lot of discarded@electrical appliances are to be shredded and pulverized. These processes@produce dusts, heat, collision sparks, etc. which might lead to dust@explosion. Actually, some dust explosion accidents at the recycling@facilities are reported. To maintain safe operations of the recycling@process, the authors investigated the minimum explosion concentration,@ignition temperature, characters of ignition source, etc. It is shown that@he dusts produced in the recycling process are sensitive for explosion.@Also, some optimum conditions for ignition (ignition energy, spark gaps and@ignition duration) of the dusts are elucidated.



Selective Detection of Bacteria by Using Dielectrophoretic Impedance Measurement Method with Immobilized Antibody Electrode

Graduate School of Information Science and Electrical Engineering Kyushu Univ

Masanori SHUTOU, Junya SUEHIRO and Masanori HARA

This paper describes a selective detection technique of bacteria based on dielectrophoresis and electrical impedance measurements. The authors have previously proposed a detection technique of biological particles called DEPIM (dielectrophoretic impedance measurement) method using positive dielectrophoretic force to capture biological cells in suspension onto an interdigitated microelectrode array.  In this study, the authors demonstrated a selective DEPIM method by combining antigen-antibody reaction with the DEPIM. Antibody molecules were immobilized onto the microelectrode surfaces before the application of dielectrophoresis so that only antibody-specific bacteria would be bound to the immobilized antibody. The proposed method provided the means whereby that specific bacteria could be selectively left between the electrode gap when the electric field was reduced after the preliminary DEP cell collection procedure. It was found that Escherichia coli (E. coli) could be left between the electrode gap on which E. coli-specific antibody was immobilized in advance. The electrode conductance proportionally increased with the number of bacteria left between the electrode gap, although some bacteria adhered to the glass substrate without immobilized antibody. These results suggest that the proposed method may be applicable to selective bacteria detection.



A Theoretical Model of Fine Particles Collection in the Dielectrophoretic Filter

Graduate School of Information Science and Electrical Engineering Kyushu Univ.

Manabu IMAMURA, Guangbin ZHOU, Junya SUEHIRO and Masanori HARA

The authors have previously proposed a dielectrophoretic (DEP) filter, which utilized positive DEP force to capture fine particles suspended in liquid. In this study, a theoretical model of particle collection in the DEP filter is newly proposed. The model can predict a particle collection region in which suspended particles can be trapped by positive DEP force against drag force exerted by streaming suspension liquid. Experimental results of biological particle elimination using the DEP filter were compared with the theoretical prediction based on the proposed model. Theoretical values of the maximum number of cells trapped by the DEP filter were in good agreement with experimental ones. It was confirmed that both electric field amplitude and suspension liquid flow rate were crucial parameters that considerably affected the DEP filter performance.



Selective Elimination of Viable and Nonviable Cells Using Dielectrophoretic Filter

Graduate School of Information Science and Electrical Engineering Kyushu Univ.

Guangbin ZHOU, Manabu IMAMURA, Junya SUEHIRO and Masanori HARA

The authors have previously proposed a dielectrophoretic (DEP) filter, which utilized positive DEP force to capture fine particles suspended in liquid. It was found that the DEP filter could eliminate yeast cells suspended in water. It is expected that the DEP filter also can selectively eliminate contaminant particles according to their dielectric properties. In this study, selective separation of viable and nonviable yeast cells was tested using the DEP filter. The optimal field frequency for the selective cell separation was determined as 1 MHz by theoretical calculation and preliminary experiment. Viable yeast cells were selectively eliminated from a mix suspension of viable and nonviable yeast cells at 1 MHz field frequency. As a result, relative ratio of viable cells decreased from 50 % to 0.5 % in an hour by using the DEP filter.



Observation of the behavior of magnetotactic bacteria under the magnetic field

Toyohashi Univ. of Technology

Yoshihiro KANAGAWA, Sabro TANAKA and Akira HIRAISHI

Magnetotactic bacteria and unfunctionated magnetotactic bacteria whose flagellum did not move, were exposed to a rotating magnetic field.  Then the behavior of the bacteria was observed.  Normal magnetotactic bacteria rotated so that they draw a circle.  The rotation velocity showed the maximum at 0.5-1 mT.  In contrast, the unfunctionated bacteria were connected each other and they rotated by themselves on that spot.  The connected chain could be separated by increase of the frequency.  This phenomenon was not seen in the normal magnetotactic bacteria.  Moreover, when the unfunctionated magnetotactic bacteria were exposed to a gradient magnetic field, they were attracted to a high gradient side.



Pulse sterilization characteristics of ring and spiral electrode system

Department of Biological and Chemical Engineering, Gunma University

Neide Miho Ishida, Erina Shimizu, Anto Tri Sugiarto, Takayuki Ohshima and Masayuki Sato

The effect of pulsed electric field treatment on bakerfs yeast and Escherichia coli K-12 suspended in sterilized 1.1% NaCl solution was investigated using two types of electrode system, ring-to-cylinder and spiral electrodes. For ring-to-cylinder electrode system, the microbial inactivation was efficient when the insulating plate with a hole was inserted between ring and cylinder electrode. For spiral electrode system, an efficient microbial inactivation was achieved at low frequency with high applied voltage.



The proposal of Immunoassay using cooling method by High-Tc SQUID

Toyohashi Univ. of Technology

Takemasa MATSUDA , Masashi UCHIDA, Saburo TANAKA

This paper describes the new quantitative-analysis method of this immunoassay. A new method we have developed is the method that magnetic particle labeled second antibody is used and the signal was easured sensitive SQUID (Superconducting Quantum Interference Device) magnetic sensor. However, there is some problem that the signal is small because of the super-paramagnetic properties of the particles. This small signal is due to its thermal disorder. If thermal disorder is lowered, the direction of the magnetic moment in a particle will be aligned to the same direction. As a result, the signal will be increased. Thus if the temperature of the particles was lowered, we expect to obtain a larger signal than the conventional method. We describe the experiment method of this immunoassay and the result.