Optical study of OH radical in a wire-plate pulsed corona discharge

Article abstract of DOI:10.1016/j.saa.2005.05.033

In this study, the emission spectra of OH (A²Σ → X²Π, 0-0) emitted from the high-voltage pulsed corona discharge (HVPCD) of N₂ and H₂O mixture gas and humid air in a wire-plate reactor were successfully recorded against a severe electromagnetic interference coming from HVPCD at one atmosphere. The relative vibrational populations and the vibrational temperature of N₂ (C, v′) were determined. The emission spectra of the Δv=+1 (1-0, 2-1, 3-2, 4-3) vibration transition band of N₂ (C³Π_u → B³Π_g) is simulated through gauss distribution. The emission intensity of OH (A²Σ → X²Π, 0-0) has been exactly gotten by subtracting the emission intensity of the Δv=+1 vibration transition band of N₂ (C³Π _u → B³Π_g) from the overlapping spectra. The relative population of OH (A²Σ) has been obtained by the emission intensity of OH (A²Σ → X²Π, 0-0) and Einstein's transition probability. The influences of pulsed peak voltage and pulse repetition rate on the relative population of OH (A ²Σ) radicals in N₂ and H₂O mixture gas and humid air are investigated separately. It is found that the relative population of OH (A²Σ) rises linearly with increasing the applied peak voltage and the pulse repetition rate. When the oxygen is added in N₂ and H₂O mixture gas, the relative population of OH (A²Σ) radicals decreases exponentially with increasing the added oxygen. The main involved physicochemical processes have also been discussed.

Full text of DOI:10.1016/j.saa.2005.05.033

Spectrochimica Acta Part A 63 (2006) 477–482
Optical study of OH radical in a wire-plate pulsed corona discharge
∗
Wenchun Wang , Su Wang, Feng Liu, Wei Zheng, Dezhen Wang
State Key Laboratory of Materials Modification by Laser, Ion and Electron beams, Dalian University of Technology,
Dalian 116024, PR China
Received 13 April 2005; accepted 11 May 2005
Abstract
2
2
In this study, the emission spectra of OH (A ꢀ → X ꢁ, 0–0) emitted from the high-voltage pulsed corona discharge (HVPCD) of N
2
and H O mixture gas and humid air in a wire-plate reactor were successfully recorded against a severe electromagnetic interference coming
from HVPCD at one atmosphere. The relative vibrational populations and the vibrational temperature of N
2
ꢀ
2
(C, v ) were determined. The
3
3
emission spectra of the ꢂv = +1 (1–0, 2–1, 3–2, 4–3) vibration transition band of N
2
(C ꢁ
u
→ B ꢁ
g
) is simulated through gauss distribution.
2
2
The emission intensity of OH (A ꢀ → X ꢁ, 0–0) has been exactly gotten by subtracting the emission intensity of the ꢂv = +1 vibration
3
3
2
transition band of N
2
(C ꢁ
u
2
→ B ꢁ
g
) from the overlapping spectra. The relative population of OH (A ꢀ) has been obtained by the emission
2
intensity of OH (A ꢀ → X ꢁ, 0–0) and Einstein’s transition probability. The influences of pulsed peak voltage and pulse repetition rate on
2
the relative population of OH (A ꢀ) radicals in N
2
and H
2
O mixture gas and humid air are investigated separately. It is found that the relative
2
population of OH (A ꢀ) rises linearly with increasing the applied peak voltage and the pulse repetition rate. When the oxygen is added in
2
N
2
and H
involved physicochemical processes have also been discussed.
2005 Elsevier B.V. All rights reserved.
2
O mixture gas, the relative population of OH (A ꢀ) radicals decreases exponentially with increasing the added oxygen. The main
©
Keywords: OH Radicals; Emission spectrum; Pulsed corona discharge; Water vapor; Relative population
1
. Introduction
for their strong oxidation in many physicochemical processes
10–11].
Recently, there have been a number of studies regarding
[
Pulsed corona discharge is one of non-thermal plasma
characterized by low gas temperature and high-electron tem-
perature. By HVPCD, more electrical energy input goes into
the production of energetic electrons than gas heating [1].
High-energy electrons (whose energy is in range of 5–20 eV)
generated by HVPCD can efficiently dissociate, excite and
ionize N2, O2 and H2O into oxygenated radicals (OH, HO2,
O, H, etc.) or active species (O3, H2O2, etc.) [2]. OH, O,
H, N, HO2, N , N2 and O3, etc., active species with strong
reactivity generated by HVPCD are considered important in
removal of acid gases from flue gases, organic compounds
removal from water, bacterial decontamination, VOCs
decomposition and destruction of other toxic compounds,
etc., fields [3–9]. Especially, OH radicals play the central role
the OH radicals [12–19]. Ono and Oda [12–15] had mea-
sured the OH radicals generated by a pulsed discharge by
laser-induced fluorescence with a tunable KrF excimer laser
and discussed the O radical’s role to generate OH radical.
Sun et al. [16] did some optical studies of active species
(OH, O and H) produced by a pulsed streamer corona
discharge in water. The influence of ultraviolet illumination
on OH formation in dielectric barrier discharges (DBD)
of Ar, O2 and H2O mixture was also studied [17]. Su
et al. [18] introduced a new method by measuring the
amount of CO2 produced through oxidation of CO by
OH radicals for the quantitative measurement of OH.
Park et al. [19] investigated additive effect of C2H4, H2O,
H2O2 on the emission intensity of OH and NO/NO2/NOx
reduction and analyzed the related reaction mechanism
in corona discharge process using a wire-cylinder plasma
reactor.
+
+
∗
Corresponding author. Tel.: +86 411 84709795–16;
fax: +86 411 84709304.
E-mail address: wangwenc@dlut.edu.cn (W. Wang).
1
386-1425/$ – see front matter © 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2005.05.033

4
78
W. Wang et al. / Spectrochimica Acta Part A 63 (2006) 477–482
In most of literatures, needle-plate or wire-cylinder is
used as discharge electrode. In this article, we present the
2
2
diagnostic results of OH (A ꢀ → X ꢁ, 0–0) emission
spectra in HVPCD plasma with wire-plate electrode struc-
ture, which can produce more uniform corona discharge
near the wires and is more close to industrial application.
The emission spectra of the ꢂv = +1 (1–0, 2–1, 3–2, 4–3)
3
3
vibration transition band of N2 (C ꢁu → B ꢁg) is simulated
through gauss distribution. The emission intensity of OH
2
2
(
A ꢀ → X ꢁ, 0–0) has been exactly gotten by subtracting
the emission intensity of the ꢂv = +1 vibration transition
3
3
band of N2 (C ꢁu → B ꢁg) from the overlapping spectra.
2
The relative population of OH (A ꢀ) has been obtained
2
2
by the emission intensity of OH (A ꢀ → X ꢁ, 0–0) and
Einstein’s transition probability. The influences of peak
voltage and pulse repetition rate on the relative population of
Fig. 2. Typical waveforms of discharge voltage and discharge current in N2
and H2O mixture.
2
OH (A ꢀ) radicals in N2 and H2O mixture gas and humid air
are investigated under severe electromagnetic interference
caused by HVPCD itself at one atmosphere. When the oxy-
gen is added in N2 and H2O mixture gas, the varying of the
relative population of OH (A ꢀ) radicals is investigated. The
main involved physicochemical processes have also been
discussed.
high-voltage pulse with a rising time of 40 ns, a pulse width
of about 500 ns and an adjustable repetition rate in range of
0–200 Hz. The discharge voltage is measured with an oscil-
loscope (Tektronix TDS3052B) and a 1:1000 high-voltage
probe (Tektronix P6015A 1000 × 3.0pF 100 Mꢃ). The dis-
charge current is measured with a current probe (Tektronix
TCP202). Fig. 2 shows the waveforms of a discharge voltage
and current. The pulsed corona discharge was generated in a
stainless-steel chamber so that the environmental conditions
could be controlled. The discharge chamber could be
evacuated with a rotary pump. The reactor utilizes wire-plate
electrode of which can be the 5–30 mm adjustable thick gas
spacing, the stainless-steel wire-plate electrode is placed
in the center of a stainless-steel chamber and the discharge
plasma is produced in the gas spacing. A stainless steel plane
2
2
. Experimental setup
The experimental setup is illustrated schematically in
Fig. 1. It is composed of a pulsed power supply, a discharge
reactor, an optical detection system and a gas-mixing
chamber. The power supply including charge and discharge
circuit is mainly composed of a DC high-voltage unit, a pulse
generator and a spark gap. The pulsed power can supply
(56 mm × 56 mm)formsthegroundedelectrode. Thepositive
high-voltage corona stainless steel wire, 48 mm long, 0.2 mm
in diameter and 20 mm in space between each wire, is fixed
8
mm apart from the cathode plate. A quartz optical fiber head
was parallelly placed to the wire electrode. In order to reduce
the interference of discharge pulses to the detection system
and other instruments, the high-voltage pulse power supply
is placed in a two-layer shielding box. Both the pulsed power
supply and the reactor are connected to the ground separately.
The optical emission from the discharge region is collected by
a MODEL SP-305 grating monochrometer (grating groove
is 1200 lines/mm, glancing wavelength is 350 nm). After the
diffraction of the grating, the output spectral light is converted
into an electrical signal by a photo multiplication tube (mode
R928) and the output of the PMT is recorded by a computer.
High purity N2 (99.999%) and High purity O2 (99.999%)
are used as discharge gases under the gas pressure of
5
1
.013 × 10 Pa. The N2 bubbles the water to control humid-
◦
ity. The temperature of the water is heated at 100 C. When
the N2 bubbles through the water and uniformly diffuses
into the discharge space, the gas temperature is about 80 C.
◦
The water vapor concentration is about 10% in discharge
chamber.
Fig. 1. Schematic of the experimental setup.

W. Wang et al. / Spectrochimica Acta Part A 63 (2006) 477–482
479
3
. Experimental results and discussion
emission spectrum of the ꢂv = +1 vibration transition
3 3
band of N2 (C ꢁu → B ꢁg). Therefore, it is necessary to
subtract the emission intensity of the ꢂv = +1 vibration
3
.1. The measurement of the OH radical emission
3
3
spectra
transition band of N2 (C ꢁu → B ꢁg) from the overlapping
2 2
spectra to get the emission intensity of OH (A ꢀ → X ꢁ,
ꢀ
In the non-equilibrium plasma generated by HVPCD at
0–0). The relative vibrational population of N2 (C, v ) can
one atmospheric pressure, electrons with much bigger migra-
tion rates can be speeded up to 2–20 eV in kinetic energy
be determined though the Eq. (1):
2
3
S
ꢀ
ꢀꢀ ∝ Nv
ꢀ
(FC)
ꢀ
ꢀꢀ R (r
ꢀ
ꢀꢀ )ν
ꢀ ꢀꢀ
v v
(1)
v v
v v
e
v v
[20]. The non-elastic collisions of the energetic electrons
with H2O, N2 and O2 molecules will induce H2O, N2 and O2
molecules to be dissociated, excited and ionized. The radi-
where S
ꢀ
ꢀꢀ is the integral emission intensity, Nv
ꢀ
the pop-
v v
ulation of the electronic excitation state vibrational energy
−
ꢀ
level v , (FC)
ꢀ ꢀꢀ the corresponding Frank–Condon factor,
v v
cals and active species of OH, HO2, O, H, N, O3, H2O2, O2 ,
+
+
N and N2 , etc., can be produced. Fig. 3A shows a typical
emission spectrum produced by a positive pulsed corona dis-
charge of N2 and H2O mixture at one atmosphere, 24 kV
peak voltage and 40 Hz pulse repetition rate. The emission
Re(r
ꢀ
ꢀꢀ ) the electronic transition moment and R (r
nearly constant, v
quency. By calculating the integral emission intensity S
ꢀ
ꢀꢀ ) is
v v
e
v v
ꢀ ꢀꢀ is the corresponding transition fre-
v v
ꢀ ꢀꢀ
v v
of the ꢂv = −3 and the ꢂv = −4 vibration transition bands
2
2
3
3
spectrum consists mainly of OH (A ꢀ → X ꢁ, 0–0) and N2
of N (C ꢁ → B ꢁ ), the relative vibrational population
2
u
g
3
3
ꢀ
(
C ꢁu → B ꢁg 1–0, 315 nm).
of N (C, v ) in present experimental condition can be deter-
2
mined N0:N1:N2:N3:N4 = 1.00:0.352:0.135:0.063:0.031 by
Eq. (1). And then the vibratonal temperature of N2 (C) can
be determined by the following equation:
3
.2. The relative vibrational population and the
ꢀ
vibrational temperature of N2 (C, v )
N1
From Fig. 3A, we can see that the emission spectrum
of OH (A ꢀ → X ꢁ, 0–0) is seriously interfered by the
−ꢂE/kTv
=
e
(2)
2
2
N0
where N1 and N0 is the relative vibrational population of
the 1 and 0 vibrational states, respectively. ꢂE is the energy
difference between the 1 and 0 vibrational states and k
is the Boltzman’s constant. Tv stands for the vibrational
temperature. Therefore, the vibrational temperature between
the 1 and 0 vibrational states can be determined, and the
vibrational temperatures between the 2 and 1, 3 and 2, 4 and
3
vibrational states also can be determined with the same
method. At our present experimental conditions, the mean
vibrational temperature of N2 (C) is 2616.3 K.
The emission intensity of the ꢂv = +1 (1–0, 2–1, 3–2,
3
3
4
–3) vibration transition band of N2 (C ꢁu → B ꢁg) can be
determined by Eq. (1) with the relative vibrational population
ꢀ
ofN2 (C, v ), Frank–Condonfactorandthespectrumresponse
of photomultiplier tube. Since the experimental pressure is at
one atmosphere, gas molecule collision frequency is about
10
10
times per second by gas dynamics. The radiation life-
time of the N2 (C) state is about 40 ns, therefore the N2
C) molecules collide with gas molecules about 400 times
(
in a second. The rotational equilibrium is reached in each
vibrational state of the N2 (C) state, and then the vibrational
distribution can be described by the same expression. Due to
the difficulty of determining the exact emission spectrum line
shape function, a Gaussian form was used for the deconvo-
lution of the overlapping emission spectrum (Fig. 3B). The
emission spectra of the ꢂv = +1 (1–0, 2–1, 3–2, 4–3) vibra-
3
3
tion transition band of N2 (C ꢁu → B ꢁg) can be deduced
2
2
Fig. 3. (A) Typical emission spectrum of OH (A ꢀ → X ꢁ, 0–0) and N2
quite accurately from the simulation process. And then the
3
3
(
C ꢁu → B ꢁg) generated by pulsed corona discharge in N2 and H2O mix-
2
2
emission intensity of OH (A ꢀ → X ꢁ, 0–0) can be exactly
get by subtracting the emission intensity of the ꢂv = +1
ture at 24 kV peak voltage and 40 Hz pulse repetition rate. (B) The emission
2
2
intensity of OH (A ꢀ → X ꢁ, 0–0) obtained through the simulation of the
3
3
3
emission spectra of the ꢂv = +1 vibration transition band of N2 (C ꢁu →
vibration transition band of N2 (C ꢁu → B ꢁg) from the
3
ꢀ
B ꢁg) by the Gauss profile and the relative populations of N2 (C, v ).
overlapping spectra.

4
80
W. Wang et al. / Spectrochimica Acta Part A 63 (2006) 477–482
The relation between the emission intensity S and the
excited state relative population is given as follows:
S = NAhν
(3)
where A is the Einstein’s transition probability, h the Planck
constant and ν is the transition frequency. Therefore, the
2
relative population of OH (A ꢀ) can be determined by
2
2
Eq. (3) with the emission intensity of OH (A ꢀ → X ꢁ,
0
–0) and the corresponding Einstein’s transition probability
8
−1
(A(OH) = 0.0145 × 10 s ).
3
.3. The effects of peak voltage and frequency on the
2
2
relative population of OH (A ꢀ → X ꢁ, 0–0)
2
Fig. 5. The relative population of OH (A ꢀ) as a function of peak voltage
When the wire-plate electrode is placed in air, the N2 and
H2O mixture gas uniformly diffuse into the discharge area
at the same flux and experimental conditions with Fig. 3A.
The emission spectrum produced by a positive pulsed corona
discharge is recorded as shown in Fig. 4.
at one atmosphere and 40 Hz discharge repetition rate.
air vary as a function of peak voltage. The repetition rate
of pulsed discharge is 40 Hz and is kept constant during
the measurements. The flow rate of N2 into the reactor is
kept at 200 ml/min. From Fig. 5, we can see that the relative
It can be seen that the emission intensities of OH
2
2
3
3
(
A ꢀ → X ꢁ, 0–0) and N2 (C ꢁu → B ꢁg) in Fig. 3A are
2
2
population of OH (A ꢀ → X ꢁ, 0–0) increase linearly with
much larger than those in Fig. 4. Some mechanisms for the
differences are discussed in the following:
increasing peak voltage.
OH radicals are mainly produced by electron–molecule
collision process. The reaction is as follows:
(
1) In Fig. 4, there are some of O2 in air. The concentra-
tion of N2 in Fig. 4 is lower than that in Fig. 3A in
discharge space. Therefore, the emission intensity of N2
e + H2O → e + H + OH
(4)
3
3
(C ꢁu → B ꢁg) in Fig. 4 is certainly weaker than that
Because a higher peak voltage can cause an increase in the
high-energy electron density and the electron mean energy,
in Fig. 3A.
2
2
(
2) The O2 capture a large numbers of electrons in Fig. 4
and becomes negative ions. So the densities of the elec-
trons in Fig. 4 are much lower than that in Fig. 3A under
the same discharge conditions. The emission intensity
the relative population of OH (A ꢀ → X ꢁ, 0–0) increases
linearly with peak voltage.
The effect of pulse repetition rate on the relative popu-
2
2
lation of OH (A ꢀ → X ꢁ, 0–0) is shown in Fig. 6. The
power supply voltage is 20 kV and is kept constant during
the measurements. The flow rate of N2 into the reactor is
kept at 200 ml/min. From Fig. 6, we can see that the rela-
2
2
3
3
of OH (A ꢀ → X ꢁ, 0–0) and N2 (C ꢁu → B ꢁg) is
obviously weakened by the oxygen component of air in
Fig. 4.
2
2
tive population of OH (A ꢀ → X ꢁ, 0–0) increase linearly
with increasing repetition rate of pulsed discharge. For the
peak voltage is not changed, per unit pulse discharge creates
the nearly same number of radicals and active species. Thus
Fig. 5 clearly shows that the relative population of OH
2
2
(
A ꢀ → X ꢁ, 0–0) of N2 and H2O mixture gas and humid
2
2
Fig. 4. Typical emission spectrum of OH (A ꢀ → X ꢁ, 0–0) and N2
3
3
2
(
C ꢁu → B ꢁg) generated by pulsed corona discharge in humid air at 24 kV
Fig. 6. The relative population of OH (A ꢀ) as a function of discharge
peak voltage and 40 Hz pulse repetition rate.
repetition rate at one atmosphere and 20 kV peak voltage.

W. Wang et al. / Spectrochimica Acta Part A 63 (2006) 477–482
481
2
OH (A ꢀ) greatly.
OH + O → H + O2
OH + O3 → HO2 + O2
(9)
(10)
Because of the depletion of the OH radicals and the free
2
electrons, the relative population of OH (A ꢀ) is decreasing
with the added oxygen.
For further understanding of the observed phenomena and
the mechanism involved, a detailed kinetic simulation of the
HVPCD plasma is underway and will be reported later.
4
. Conclusions
2
Fig. 7. The relative population of OH (A ꢀ) as a function of O2 flow rate at
4 kV peak voltage and 40 Hz repetition rate. The solid line is experimental
curve. The dot line is obtained by the exponential fitting method.
2
In this study, we have successfully recorded the emis-
2
2
sion spectra of OH (A ꢀ → X ꢁ, 0–0) in the positive
pulse corona discharge with wire-plane electrode at one
atmosphere. The severe electromagnetic interference caused
by HVPCD itself has been overcome by double shielding
and specially designed multiple grounding of the discharge
source and the reactor. The relative vibrational populations
2
2
the relative population of OH (A ꢀ → X ꢁ, 0–0) increase
linearly with increasing pulse repetition rate.
3
.4. The Effects of O2 addition on the relative
population of OH (A ꢀ → X ꢁ, 0–0)
2
2
ꢀ
and the vibrational temperature of N2 (C, v ) were deter-
mined. The emission spectra of the ꢂv = +1 (1–0, 2–1, 3–2,
To investigate the effect of oxygen on the relative popula-
3
3
4
–3) vibration transition band of N2 (C ꢁu → B ꢁg) is sim-
2
2
tion of OH (A ꢀ → X ꢁ, 0–0), oxygen is added in the N2
and H2O mixture in positive pulsed corona discharge. When
oxygen is added, the added O2 capture a lot of free electrons
ulated through gauss distribution. The emission intensity of
2
2
OH (A ꢀ → X ꢁ, 0–0) has been exactly gotten by subtract-
ingtheemissionintensityoftheꢂv = +1vibrationtransition
−
and form O2 ions. Thus, the added O2 decrease greatly the
3
3
band of N2 (C ꢁu → B ꢁg) from the overlapping spectra.
density of free electrons and the electron mean energy.
The effects of the concentration of O2 on the relative pop-
2
TherelativepopulationofOH(A ꢀ)hasbeenobtainedbythe
2
2
emission intensity of OH (A ꢀ → X ꢁ, 0–0) and Einstein’s
2
ulation of OH (A ꢀ) are shown in Fig. 7. Fig. 7 clearly shows
transition probability. It is found that the relative population
2
that the relative population of OH (A ꢀ) varies as a function
2
of OH (A ꢀ) increase linearly with the peak voltage and the
of O2 flow rate at 9 different oxygen flow rates of 5, 10, 15, 20,
5, 30, 40, 50 and 60 ml/min at 24 kV peak voltage and 40 Hz
pulse repetition rate in N2 and H2O mixture gas and humid
air. When the different oxygen flows are added in N2 and
2
pulse repetition rate. The flow rate of N2 into the reactor is
kept at 200 ml/min. It can be seen that the relative population
2
H2O mixture gas, the relative population of OH (A ꢀ) radi-
cals decreases exponentially with increasing the flow rate of
oxygen.
2
of OH (A ꢀ) is in the exponentially decreasing with the flow
rate of oxygen.
In order to explain the observed experimental phenom-
ena, we will further discuss the physicochemical processes of
interaction when oxygen is added. Firstly the added O2 can be
dissociation by the reactions (5)–(7) in the electron–molecule
interactions of electrons and O2:
Acknowledgements
The author would like to thank professor Xuechu Li for
friendly discussion and suggestion. This work is supported
by the united fund of the National Natural Science Founda-
tion Committee of China and Engineering Physical Institute
of China granted under No. 10276008 and the fund of Liaon-
ing Province Natural Science Foundation Committee granted
under No. 20022138.
−
e + O2 → O + O
(5)
(6)
(7)
1
e + O2 → e + O + O( D)
+
e + O2 → O + O + 2e
1
A lot of O( D) and O atoms can be produced. One and Oda
[
14] have pointed out that in a humid air, most of the OH can
1
be produced by interaction of O( D) and H2O:
References
1
O( D) + H2O → 2OH
(8)
[
1] A. Mizuno, J.S. Clements, R.H. Davis, IEEE Trans. Ind. Appl. 22
1986) 516.
(
At the same time, the lots of O atoms and O3 molecules pro-
duced by the added O2 can react with OH and then decrease
[2] R.P. Dahiya, S.K. Mishra, A. Veefkind, IEEE Trans. Plasma Sci. 21
(1993) 346.

4
82
W. Wang et al. / Spectrochimica Acta Part A 63 (2006) 477–482
[
[
[
3] A.T. Sugiarto, S. Ito, T. Ohshima, M. Sato, J.D. Skalny, J. Electro-
statics 58 (2003) 135.
4] A. Abou-Ghazala, S. Katsuki, K.H. Schoenbach, F.C. Dobbs, K.R.
Moreira, IEEE Trans. Plasma Sci. 30 (2002) 1449.
5] M. Yamamoto, M. Nishioka, M. Sadakata, J. Electrostatics 56 (2002)
[12] R. Ono, T. Oda, IEEE Trans. Ind. Appl. 37 (3) (2001) 709.
[13] R. Ono, T. Oda, IEEE Trans. Ind. Appl. 36 (1) (2000) 82.
[14] R. Ono, T. Oda, Thirty-Fourth IAS Annual Meeting, Industry Appli-
cations Conference, Conference Record of the 1999 IEEE, vol. 3,
1999, p. 1461.
1
73.
[15] R. Ono, T. Oda, J. Phy. D: Appl. Phys. 35 (2002) 2133.
[16] B. Sun, M. Sato, J.S. Clements, J. Electrostatics 39 (3) (1997) 189.
[17] Z. Falkenstein, J. Appl. Phys. 81 (11) (1997) 7158.
[18] Z. Su, H.H. Kim, M. Tsutsui, K. Takashima, A. Mizuno, Thirty-
Fourth IAS Annual Meeting, Industry Applications Conference, Con-
ference Record of the 1999 IEEE, vol. 3, 1999, p. 1473.
[19] C.W. Park, J.W. Hahn, D.N. Shin, The Pacific Rim Conference on
Lasers and Electro-Optics, CLEO/Pacific Rim ’1999, vol. 2, 1999,
p. 356.
[
[
[
6] T. Oda, J. Electrostatics 57 (2003) 293.
7] U. Roland, F. Holzer, F.D. Kopinke, Catal. Today 73 (2002) 315.
8] G.W. Shao, J. Li, W.L. Wang, Z.H. He, S.L. Li, J. Electrostatics 62
(
2004) 1.
9] H. Lin, X. Gao, Z.Y. Lou, K.F. Cen, M.X. Pei, Z. Huang, Fuel 83
2004) 1251.
10] V.A. Lozovsky, I. Derzy, S. Cheskis, Chem. Phys. Lett. 284 (1998)
07.
11] A.A. Joshi, B.R. Locke, P. Arce, W.C. Finney, J. Hazard. Mater. 41
1995) 3.
[
(
[
[
4
[20] B. Eliasson, U. Kogelschatz, J. Phys. B: At. Mol. Phys. 19 (1986)
1241.
(