Jaroslav Kristof | Shizuoka University (original) (raw)
Papers by Jaroslav Kristof
Simultaneous vacuum UV and broadband UV–NIR plasma spectroscopy to improve the LIBS analysis of light elements
Plasma Sources Science and Technology, Sep 10, 2018
This work studies the ability of laser-induced breakdown spectroscopy (LIBS) to improve the detec... more This work studies the ability of laser-induced breakdown spectroscopy (LIBS) to improve the detection of light elements such as silicon (Si), boron (B), carbon (C), and sulfur (S). In this study, the plasma decay over time was simulated using the LIBS application provided by NIST, obtaining spectra in the spectral range ranging from the vacuum ultraviolet (VUV) to the near infrared (NIR) region. Since the electron density (n e) and plasma temperature (T e) decrease during the decaying process, the intensities of emission lines from neutral, singly ionized, and doubly ionized species were calculated. The results allowed us to determine the range of suitable n e and T e for experimental measurements, and to construct a Saha–Boltzmann (SB) plot using neutral, singly ionized, and doubly ionized species. Samples containing Si, B, C, and S were measured at delays of 100–1000 ns after the laser shot at low pressure (13 mbar) in a helium atmosphere. From the measured data, suitable lines were chosen in the VUV range to calculate the T e of plasma for each sample at different delays. The results demonstrate that due to the inclusion of multiple species across VUV–UV–NIR, an appreciable improvement in the accuracy of T e was obtained, which is an essential factor for calibration-free LIBS (CF-LIBS).
Kinetics of N2(B3Πg) and N2(C3Πu) states in N2-Ar discharges sustained by a RF helical coupling device
HAL (Le Centre pour la Communication Scientifique Directe), Jul 10, 2012
Rotational temperatures in RF plasma of Ar-H2O mixtures at low and moderated pressure
An Ar-H2O discharge with Ar content from 0 to 95 % at 67 and 266 Pa have been studied by optical ... more An Ar-H2O discharge with Ar content from 0 to 95 % at 67 and 266 Pa have been studied by optical emission spectroscopy. The plasma was excited at 27 MHz by a helical cavity with a power set at 30 W. The rotational temperatures of N2(C3Πu) and OH(A2 Σ + ) emitters were determined through spectral simulations. For added Ar percentages smaller than 95 %, the rotational temperature of N2(C3Πu) state was shown to be constant and equal to the gas temperature with a value of 450 ± 50 K. The effect of energy transfer from argon metastables is probably weak considering the results on the rotational temperature of N2(C3Πu) at 95 % Ar / 5 % H2O. The experimental OH spectra could be fitted only with a two temperatures model; T1= 450 K for both pressures and T2= 15000 K with a contribution of 22 and 32 % for 266 and 67 Pa, respectively, as result of the excitation mechanisms involving electron impact collision with water.
Vacuum UV emission spectroscopy of discharge excited by a RF helical coupling device in N$_{2}$-Ar mixtures
Bulletin of the American Physical Society, 2010
Spectrochimica Acta Part B: Atomic Spectroscopy, 2019
Surface engineering by plasma : spectroscopic characterization of an N2-Ar discharge
Vacuum UV and UV spectroscopy of a N2–Ar mixture discharge created by an RF helical coupling device
Plasma Sources Science and Technology, 2010
Optical emission spectroscopy in vacuum ultraviolet and UV spectral ranges is applied to study de... more Optical emission spectroscopy in vacuum ultraviolet and UV spectral ranges is applied to study densities, and vibrational and rotational temperatures of the N2 molecule in a nitrogen-argon (0-95% Ar) plasma sustained at a pressure of 400 Pa by a helical cavity supplied with a power of 28 W and an excitation frequency of 27 MHz. The spatial investigation of all
Plasma Medicine
Introduction of molecules into the cells is part of gene transfection or cell-mediated drug deliv... more Introduction of molecules into the cells is part of gene transfection or cell-mediated drug delivery. The molecules can effectively decrease side effects of the drug and increase their targeting. Air microplasma discharge was used to treat rat intestinal cells to induce absorption of fluorescein isothiocyanate-dextran with a molecular weight of 150 kDa (FD-150). Absorption of FD-150 was confirmed by observation using fluorescence microscope. Efficiency of absorbance was estimated by a plate reader, and the viability of the cells was measured by a cell counter. The viability of the cells was proportional to the decrease in treatment time and the increase in treatment distance from the microplasma electrode. The absorption of FD-150 was found to be proportional to the increase in time and distance. No improvement in absorption or viability was observed during the incubation time. Cell treatment by the plasma-treated medium showed a lower absorption of FD-150 than direct treatment but ...
Electronics Letters, 2010
Continuous wave cavity ring-down spectroscopy using an electronically switched telecom distribute... more Continuous wave cavity ring-down spectroscopy using an electronically switched telecom distributed feedback laser module is demonstrated. By adding a compensation waveform current to the step-function switched laser current the laser wavelength stabilisation time is reduced to about 4 ms corresponding to a 200 Hz utmost ring-down transient repetition rate.
Energies
Gaseous sulfur compounds are emitted from many facilities, such as wastewater facilities or bioma... more Gaseous sulfur compounds are emitted from many facilities, such as wastewater facilities or biomass power plants, due to the decay of organic compounds. Gaseous dimethyl sulfide removal by ozone catalytic oxidation was investigated in this study. A Vacuum-Ultra-Violet (VUV) xenon excimer lamp of 172 nm was used for ozone generation without NOx generation, and activated carbon impregnated with iodic acid and H2SO4 was utilized as a catalyst. Performance assessment of dimethyl sulfide removal ability was carried out by a dynamic adsorption experiment. Empty-Bed-Contact-Time (EBCT), superficial velocity, concentration of dimethyl sulfide, temperature and humidity were set at 0.48 s, 0.15 m/s, 3.0 ppm, 25 °C and 45%, respectively. Without ozone addition, the adsorption capacity of impregnated activated carbon was 0.01 kg/kg. When ozone of 7.5 ppm was added, the adsorption capacity of impregnated activated carbon was increased to 0.15 kg/kg. Methane sulfonic acid, a reaction product of d...
Flow Control by Dielectric Barrier Discharge Microplasma
Advances in Intelligent Systems and Computing, 2017
Dielectric barrier discharge (DBD) plasma actuators are a technology which could replace conventi... more Dielectric barrier discharge (DBD) plasma actuators are a technology which could replace conventional actuators due to their simple construction, lack of moving parts and fast response. Our study was carried out to investigate experimentally and by numerical simulations a micro scale plasma actuator energized at 1.4 kV. A multi-electrode plasma actuator was used which allowed the electrodes to be energized at different potentials or waveforms, thus changing the direction of the flow. The movement of incense particles was tracked by the high speed camera. The observation with the high speed camera showed at various time intervals the modification of the flow by the microplasma. The numerical simulation of the flow was carried out using Suzen-Huang modela and Navier-Stokes equations.
Permeability of Epidermal Layer of The Skin for Adenosine by Microplasma and Iontophoresis
2020 IEEE International Conference on Plasma Science (ICOPS), 2020
Epidermal layer of the skin, especially its upper layer called stratum corneum, is the main barri... more Epidermal layer of the skin, especially its upper layer called stratum corneum, is the main barrier to prevent foreign molecules from entering the body. However, the skin also represents a route for a drug delivery. Transdermal drug delivery has some advantages compared to other drug delivery techniques. Thus the risk of infection typical for injection delivery or metabolic changes of drug typical for oral delivery are eliminated. In the case of transdermal drug delivery, the skin barrier must be disturbed. There are several approaches how to disturb the barrier effect of stratum corneum such as electroporation, iontophoresis, sonophoresis or chemical enhancers. Using a plasma discharge for the improvement of the skin permeability is a relatively new a technique.
Inactivation of Staphylococcus Aureus by Microplasma
2021 IEEE Industry Applications Society Annual Meeting (IAS), 2021
Dielectric barrier discharge microplasma has various industry applications such as surface treatm... more Dielectric barrier discharge microplasma has various industry applications such as surface treatment, NOx removal, flow control ore biomedical applications. Transdermal drug delivery procedure could be enhanced by microplasma. Along with this procedure skin treatment in order to remove harmful bacteria is necessary. One of these harmful bacteria which lives on human skin is Staphylococcus Aureus. Microplasma was used for the sterilization of Staphylococcus Aureus. Air and Argon were used as discharge gases. The sterilization process is mainly carried out by the reactive oxygen species. Thus the highest sterilization rates were obtained by using as discharge gas air or a mixture of argon and oxygen. The applied voltages were sine wave and pulse. In the case of sine wave the ozone generation is higher thus a pulse powered microplasma discharge is preferred.
Comparison between different portions of the skin for transdermal drug delivery by Microplasma
2021 IEEE Industry Applications Society Annual Meeting (IAS), 2021
Indoor Environment, 2020
清水一男 1 , 3) ＊ ,野中大輔 2) ,クリストフ ヤロスロフ 3) ,マリウス ブラジャン 1) 1) 静岡大学 イノベーション社会連携推進機構 〒4 3 2-8 5 6 1静岡県浜松... more 清水一男 1 , 3) ＊ ,野中大輔 2) ,クリストフ ヤロスロフ 3) ,マリウス ブラジャン 1) 1) 静岡大学 イノベーション社会連携推進機構 〒4 3 2-8 5 6 1静岡県浜松市中区城北3-5-1 2) 三菱電機株式会社 静岡製作所 電子制御システム部 〒4 2 2-8 5 2 8静岡県静岡市駿河区小鹿3 丁目1 8 番1 号 3) 静岡大学創造科学技術大学院 光ナノ物質機能専攻 〒4 3 2-8 5 6 1静岡県浜松市中区城北3-5-1 S t u d yo nf i n ep a r t i c l er e mo v a l f r o m t h es u r f a c eo f ami c r o p l a s mae l e c t r o d e b ye l e c t r o s t a t i cf o r c e Ka z u oS HI MI Z U 1 , 3) ＊ , Da i s u k eNONAKA 2) , J a r o s l a vKR I S T OF 3) a n dMa r i u sB L AJ AN 1) 1) Or g a n i z a t i o nf o r I n n o v a t i o na n dS o c i a l C o l l a b o r a t i o n , S h i z u o k aUn i v e r s i t y , 3-5-1J o h o k u , Na k a-k u , Ha ma ma t s u4 3 2-8 5 6 1 , J a p a n 2) Mi t s u b i s h i E l e c t r i cC o. L t d. , S h i z u o k aDi v. , 3-1 8-1Oj i k a , S u r u g a-k u , S h i z u o k a4 2 2-8 5 2 8 , J a p a n 3) * C o r r e s p o n d i n ga u t h o r (責任著者) E-ma i l :s h i mi z u @c j r. s h i z u o k a. a c. j p ,T e l :0 5 3-4 7 8-1 4 4 3 受付：2 0 2 0 年2 月2 7 日(R e c e i v e d :2 7F e b r u a r y2 0 2 0) 受理：2 0 2 0 年5 月7 日(Ac c e p t e d :7Ma y2 0 2 0)
Study of particle removal useing microplasma electrode
The Japan Society of Applied Physics, 2018
We implanted germanium negative ions into a 100-nm-thick Si0 2 layer on Silicon substrate and hav... more We implanted germanium negative ions into a 100-nm-thick Si0 2 layer on Silicon substrate and have investigated about oxidation of implanted Ge atoms and cathode luminescence for the possibility of blue light emission. The ions were implanted into the same Si0 2 layer with three times at different energies of 50, 20, and 10 keV (multi-energy implantation). The dose amounts were 1.4 x 10 16 , 3.2 x 10 15 and 2.2 x 10 15 ions/cm 2 , respectively. Samples were annealed for 1 h at a temperature less than 900°C. The depth distribution and oxidation of implanted Ge atoms in the oxide were measured by XPS analysis with Ar etching. The depth profiles were well agreed with the cross-sectional TEM image. But some extent of Ge atoms diffused to the Si0 2 /Si interface at 900 °C. The chemical sifted spectra of Ge 2p3/2 showed about 60 % of the oxidation of Ge atom around the end of the range (EOR) even in the as-implanted sample. This oxidation was considered to be due to the excess oxygen atoms near EOR by forward of sputtered oxygen atoms from Si0 2 layer. In cathode luminescence measurement, the Ge-implanted sample after annealing at 800°C showed strongest CL peak at 3.12 eV (397 nm in wavelength) in UV-blue region at room temperature. This means the Ge-implanted sample has a possibility for light emission in the UV-blue region.
A microplasma actuator was developed for the flow control applications. It is a type of dielectri... more A microplasma actuator was developed for the flow control applications. It is a type of dielectric barrier discharge plasma actuator that due to its simple construction and no moving parts has advantages over the mechanical type of actuators used for flow control. Numerical simulations were carried out in order to analyze the induced Electro Hydro Dynamic (EHD) flow. The microplasma actuator has a thin dielectric layer with a thickness of 25 μm between the grounded and high voltage energized electrodes thus the discharge voltage is about 1 kV. The high voltage electrodes consist of alternating strip-like electrodes that are placed above a plate-like electrode with the dielectric layer in between. In the series of experiments an AC voltage with amplitude 1.4 kV and 20 kHz was applied to the electrodes. A parametric study was carried out in which the number of strip-like electrodes was varied. Thus four and eight strip-like electrodes were used and their influence on the induced EHD f...
大気圧マイクロプラズマによる植物ホルモン(エチレン)の制御
Advanced Materials Letters, 2018
A microplasma electrode was used for skin treatment using argon, oxygen, nitrogen or ambient air.... more A microplasma electrode was used for skin treatment using argon, oxygen, nitrogen or ambient air. The presence of various particles is important for the interpretation of the microplasma effect on the skin. The production of long living particles was detected by an FTIR spectrometer and the presence of air between the sample and the electrode was monitored by the O2 monitor. In the case of gases other than air, we concluded that the concentration of processing gas is at least 99.5 %. The epidermal layer of pig skin was used for observing changes caused by microplasma treatment. The XPS spectra of carbon and oxygen were analysed.
Simultaneous vacuum UV and broadband UV–NIR plasma spectroscopy to improve the LIBS analysis of light elements
Plasma Sources Science and Technology, Sep 10, 2018
This work studies the ability of laser-induced breakdown spectroscopy (LIBS) to improve the detec... more This work studies the ability of laser-induced breakdown spectroscopy (LIBS) to improve the detection of light elements such as silicon (Si), boron (B), carbon (C), and sulfur (S). In this study, the plasma decay over time was simulated using the LIBS application provided by NIST, obtaining spectra in the spectral range ranging from the vacuum ultraviolet (VUV) to the near infrared (NIR) region. Since the electron density (n e) and plasma temperature (T e) decrease during the decaying process, the intensities of emission lines from neutral, singly ionized, and doubly ionized species were calculated. The results allowed us to determine the range of suitable n e and T e for experimental measurements, and to construct a Saha–Boltzmann (SB) plot using neutral, singly ionized, and doubly ionized species. Samples containing Si, B, C, and S were measured at delays of 100–1000 ns after the laser shot at low pressure (13 mbar) in a helium atmosphere. From the measured data, suitable lines were chosen in the VUV range to calculate the T e of plasma for each sample at different delays. The results demonstrate that due to the inclusion of multiple species across VUV–UV–NIR, an appreciable improvement in the accuracy of T e was obtained, which is an essential factor for calibration-free LIBS (CF-LIBS).
Kinetics of N2(B3Πg) and N2(C3Πu) states in N2-Ar discharges sustained by a RF helical coupling device
HAL (Le Centre pour la Communication Scientifique Directe), Jul 10, 2012
Rotational temperatures in RF plasma of Ar-H2O mixtures at low and moderated pressure
An Ar-H2O discharge with Ar content from 0 to 95 % at 67 and 266 Pa have been studied by optical ... more An Ar-H2O discharge with Ar content from 0 to 95 % at 67 and 266 Pa have been studied by optical emission spectroscopy. The plasma was excited at 27 MHz by a helical cavity with a power set at 30 W. The rotational temperatures of N2(C3Πu) and OH(A2 Σ + ) emitters were determined through spectral simulations. For added Ar percentages smaller than 95 %, the rotational temperature of N2(C3Πu) state was shown to be constant and equal to the gas temperature with a value of 450 ± 50 K. The effect of energy transfer from argon metastables is probably weak considering the results on the rotational temperature of N2(C3Πu) at 95 % Ar / 5 % H2O. The experimental OH spectra could be fitted only with a two temperatures model; T1= 450 K for both pressures and T2= 15000 K with a contribution of 22 and 32 % for 266 and 67 Pa, respectively, as result of the excitation mechanisms involving electron impact collision with water.
Vacuum UV emission spectroscopy of discharge excited by a RF helical coupling device in N$_{2}$-Ar mixtures
Bulletin of the American Physical Society, 2010
Spectrochimica Acta Part B: Atomic Spectroscopy, 2019
Surface engineering by plasma : spectroscopic characterization of an N2-Ar discharge
Vacuum UV and UV spectroscopy of a N2–Ar mixture discharge created by an RF helical coupling device
Plasma Sources Science and Technology, 2010
Optical emission spectroscopy in vacuum ultraviolet and UV spectral ranges is applied to study de... more Optical emission spectroscopy in vacuum ultraviolet and UV spectral ranges is applied to study densities, and vibrational and rotational temperatures of the N2 molecule in a nitrogen-argon (0-95% Ar) plasma sustained at a pressure of 400 Pa by a helical cavity supplied with a power of 28 W and an excitation frequency of 27 MHz. The spatial investigation of all
Plasma Medicine
Introduction of molecules into the cells is part of gene transfection or cell-mediated drug deliv... more Introduction of molecules into the cells is part of gene transfection or cell-mediated drug delivery. The molecules can effectively decrease side effects of the drug and increase their targeting. Air microplasma discharge was used to treat rat intestinal cells to induce absorption of fluorescein isothiocyanate-dextran with a molecular weight of 150 kDa (FD-150). Absorption of FD-150 was confirmed by observation using fluorescence microscope. Efficiency of absorbance was estimated by a plate reader, and the viability of the cells was measured by a cell counter. The viability of the cells was proportional to the decrease in treatment time and the increase in treatment distance from the microplasma electrode. The absorption of FD-150 was found to be proportional to the increase in time and distance. No improvement in absorption or viability was observed during the incubation time. Cell treatment by the plasma-treated medium showed a lower absorption of FD-150 than direct treatment but ...
Electronics Letters, 2010
Continuous wave cavity ring-down spectroscopy using an electronically switched telecom distribute... more Continuous wave cavity ring-down spectroscopy using an electronically switched telecom distributed feedback laser module is demonstrated. By adding a compensation waveform current to the step-function switched laser current the laser wavelength stabilisation time is reduced to about 4 ms corresponding to a 200 Hz utmost ring-down transient repetition rate.
Energies
Gaseous sulfur compounds are emitted from many facilities, such as wastewater facilities or bioma... more Gaseous sulfur compounds are emitted from many facilities, such as wastewater facilities or biomass power plants, due to the decay of organic compounds. Gaseous dimethyl sulfide removal by ozone catalytic oxidation was investigated in this study. A Vacuum-Ultra-Violet (VUV) xenon excimer lamp of 172 nm was used for ozone generation without NOx generation, and activated carbon impregnated with iodic acid and H2SO4 was utilized as a catalyst. Performance assessment of dimethyl sulfide removal ability was carried out by a dynamic adsorption experiment. Empty-Bed-Contact-Time (EBCT), superficial velocity, concentration of dimethyl sulfide, temperature and humidity were set at 0.48 s, 0.15 m/s, 3.0 ppm, 25 °C and 45%, respectively. Without ozone addition, the adsorption capacity of impregnated activated carbon was 0.01 kg/kg. When ozone of 7.5 ppm was added, the adsorption capacity of impregnated activated carbon was increased to 0.15 kg/kg. Methane sulfonic acid, a reaction product of d...
Flow Control by Dielectric Barrier Discharge Microplasma
Advances in Intelligent Systems and Computing, 2017
Dielectric barrier discharge (DBD) plasma actuators are a technology which could replace conventi... more Dielectric barrier discharge (DBD) plasma actuators are a technology which could replace conventional actuators due to their simple construction, lack of moving parts and fast response. Our study was carried out to investigate experimentally and by numerical simulations a micro scale plasma actuator energized at 1.4 kV. A multi-electrode plasma actuator was used which allowed the electrodes to be energized at different potentials or waveforms, thus changing the direction of the flow. The movement of incense particles was tracked by the high speed camera. The observation with the high speed camera showed at various time intervals the modification of the flow by the microplasma. The numerical simulation of the flow was carried out using Suzen-Huang modela and Navier-Stokes equations.
Permeability of Epidermal Layer of The Skin for Adenosine by Microplasma and Iontophoresis
2020 IEEE International Conference on Plasma Science (ICOPS), 2020
Epidermal layer of the skin, especially its upper layer called stratum corneum, is the main barri... more Epidermal layer of the skin, especially its upper layer called stratum corneum, is the main barrier to prevent foreign molecules from entering the body. However, the skin also represents a route for a drug delivery. Transdermal drug delivery has some advantages compared to other drug delivery techniques. Thus the risk of infection typical for injection delivery or metabolic changes of drug typical for oral delivery are eliminated. In the case of transdermal drug delivery, the skin barrier must be disturbed. There are several approaches how to disturb the barrier effect of stratum corneum such as electroporation, iontophoresis, sonophoresis or chemical enhancers. Using a plasma discharge for the improvement of the skin permeability is a relatively new a technique.
Inactivation of Staphylococcus Aureus by Microplasma
2021 IEEE Industry Applications Society Annual Meeting (IAS), 2021
Dielectric barrier discharge microplasma has various industry applications such as surface treatm... more Dielectric barrier discharge microplasma has various industry applications such as surface treatment, NOx removal, flow control ore biomedical applications. Transdermal drug delivery procedure could be enhanced by microplasma. Along with this procedure skin treatment in order to remove harmful bacteria is necessary. One of these harmful bacteria which lives on human skin is Staphylococcus Aureus. Microplasma was used for the sterilization of Staphylococcus Aureus. Air and Argon were used as discharge gases. The sterilization process is mainly carried out by the reactive oxygen species. Thus the highest sterilization rates were obtained by using as discharge gas air or a mixture of argon and oxygen. The applied voltages were sine wave and pulse. In the case of sine wave the ozone generation is higher thus a pulse powered microplasma discharge is preferred.
Comparison between different portions of the skin for transdermal drug delivery by Microplasma
2021 IEEE Industry Applications Society Annual Meeting (IAS), 2021
Indoor Environment, 2020
清水一男 1 , 3) ＊ ,野中大輔 2) ,クリストフ ヤロスロフ 3) ,マリウス ブラジャン 1) 1) 静岡大学 イノベーション社会連携推進機構 〒4 3 2-8 5 6 1静岡県浜松... more 清水一男 1 , 3) ＊ ,野中大輔 2) ,クリストフ ヤロスロフ 3) ,マリウス ブラジャン 1) 1) 静岡大学 イノベーション社会連携推進機構 〒4 3 2-8 5 6 1静岡県浜松市中区城北3-5-1 2) 三菱電機株式会社 静岡製作所 電子制御システム部 〒4 2 2-8 5 2 8静岡県静岡市駿河区小鹿3 丁目1 8 番1 号 3) 静岡大学創造科学技術大学院 光ナノ物質機能専攻 〒4 3 2-8 5 6 1静岡県浜松市中区城北3-5-1 S t u d yo nf i n ep a r t i c l er e mo v a l f r o m t h es u r f a c eo f ami c r o p l a s mae l e c t r o d e b ye l e c t r o s t a t i cf o r c e Ka z u oS HI MI Z U 1 , 3) ＊ , Da i s u k eNONAKA 2) , J a r o s l a vKR I S T OF 3) a n dMa r i u sB L AJ AN 1) 1) Or g a n i z a t i o nf o r I n n o v a t i o na n dS o c i a l C o l l a b o r a t i o n , S h i z u o k aUn i v e r s i t y , 3-5-1J o h o k u , Na k a-k u , Ha ma ma t s u4 3 2-8 5 6 1 , J a p a n 2) Mi t s u b i s h i E l e c t r i cC o. L t d. , S h i z u o k aDi v. , 3-1 8-1Oj i k a , S u r u g a-k u , S h i z u o k a4 2 2-8 5 2 8 , J a p a n 3) * C o r r e s p o n d i n ga u t h o r (責任著者) E-ma i l :s h i mi z u @c j r. s h i z u o k a. a c. j p ,T e l :0 5 3-4 7 8-1 4 4 3 受付：2 0 2 0 年2 月2 7 日(R e c e i v e d :2 7F e b r u a r y2 0 2 0) 受理：2 0 2 0 年5 月7 日(Ac c e p t e d :7Ma y2 0 2 0)
Study of particle removal useing microplasma electrode
The Japan Society of Applied Physics, 2018
We implanted germanium negative ions into a 100-nm-thick Si0 2 layer on Silicon substrate and hav... more We implanted germanium negative ions into a 100-nm-thick Si0 2 layer on Silicon substrate and have investigated about oxidation of implanted Ge atoms and cathode luminescence for the possibility of blue light emission. The ions were implanted into the same Si0 2 layer with three times at different energies of 50, 20, and 10 keV (multi-energy implantation). The dose amounts were 1.4 x 10 16 , 3.2 x 10 15 and 2.2 x 10 15 ions/cm 2 , respectively. Samples were annealed for 1 h at a temperature less than 900°C. The depth distribution and oxidation of implanted Ge atoms in the oxide were measured by XPS analysis with Ar etching. The depth profiles were well agreed with the cross-sectional TEM image. But some extent of Ge atoms diffused to the Si0 2 /Si interface at 900 °C. The chemical sifted spectra of Ge 2p3/2 showed about 60 % of the oxidation of Ge atom around the end of the range (EOR) even in the as-implanted sample. This oxidation was considered to be due to the excess oxygen atoms near EOR by forward of sputtered oxygen atoms from Si0 2 layer. In cathode luminescence measurement, the Ge-implanted sample after annealing at 800°C showed strongest CL peak at 3.12 eV (397 nm in wavelength) in UV-blue region at room temperature. This means the Ge-implanted sample has a possibility for light emission in the UV-blue region.
A microplasma actuator was developed for the flow control applications. It is a type of dielectri... more A microplasma actuator was developed for the flow control applications. It is a type of dielectric barrier discharge plasma actuator that due to its simple construction and no moving parts has advantages over the mechanical type of actuators used for flow control. Numerical simulations were carried out in order to analyze the induced Electro Hydro Dynamic (EHD) flow. The microplasma actuator has a thin dielectric layer with a thickness of 25 μm between the grounded and high voltage energized electrodes thus the discharge voltage is about 1 kV. The high voltage electrodes consist of alternating strip-like electrodes that are placed above a plate-like electrode with the dielectric layer in between. In the series of experiments an AC voltage with amplitude 1.4 kV and 20 kHz was applied to the electrodes. A parametric study was carried out in which the number of strip-like electrodes was varied. Thus four and eight strip-like electrodes were used and their influence on the induced EHD f...
大気圧マイクロプラズマによる植物ホルモン(エチレン)の制御
Advanced Materials Letters, 2018
A microplasma electrode was used for skin treatment using argon, oxygen, nitrogen or ambient air.... more A microplasma electrode was used for skin treatment using argon, oxygen, nitrogen or ambient air. The presence of various particles is important for the interpretation of the microplasma effect on the skin. The production of long living particles was detected by an FTIR spectrometer and the presence of air between the sample and the electrode was monitored by the O2 monitor. In the case of gases other than air, we concluded that the concentration of processing gas is at least 99.5 %. The epidermal layer of pig skin was used for observing changes caused by microplasma treatment. The XPS spectra of carbon and oxygen were analysed.