• 제목/요약/키워드: plasma

검색결과 17,061건 처리시간 0.042초

Active control of amplitude and phase of high-power RF systems in EAST ICRF heating experiments

  • Guanghui Zhu;Lunan Liu;Yuzhou Mao;Xinjun Zhang;Yaoyao Guo;Lin Ai;Runhao Jiang;Chengming Qin;Wei Zhang;Hua Yang;Shuai Yuan;Lei Wang;Songqing Ju;Yongsheng Wang;Xuan Sun;Zhida Yang;Jinxin Wang;Yan Cheng;Hang Li;Jingting Luo
    • Nuclear Engineering and Technology
    • /
    • 제55권2호
    • /
    • pp.595-602
    • /
    • 2023
  • The EAST ICRF system operating space has been extended in power and phase control with a low-level RF system for the new double-strap antenna. Then the multi-step power and periodic phase scanning experiment were conducted in L-mode plasma, respectively. In the power scanning experiment, the stored energy, radiation power, plasma impedance and the antenna's temperature all have positive responses during the short ramp-ups of PL;ICRF. The core ion temperature increased from 1 keV to 1.5 keV and the core heating area expanded from |Z| ≤ 5 cm to |Z| ≤ 10 cm during the injection of ICRF waves. In the phasing scanning experiment, in addition to the same conclusions as the previous relatively phasing scanning experiment, the superposition effect of the fluctuation of stored energy, radiation power and neutron yield caused by phasing change with dual antenna, resulting in the amplitude and phase shift, was also observed. The active control of RF output facilitates the precise control of plasma profiles and greatly benefits future experimental exploration.

In-situ Endpoint Detection for Dielectric Films Plasma Etching Using Plasma Impedance Monitoring and Self-plasma Optical Emission Spectroscopy with Modified Principal Component Analysis

  • 장해규;채희엽
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
    • /
    • pp.153-153
    • /
    • 2012
  • Endpoint detection with plasma impedance monitoring and self-plasma optical emission spectroscopy is demonstrated for dielectric layers etching processes. For in-situ detecting endpoint, optical-emission spectroscopy (OES) is used for in-situ endpoint detection for plasma etching. However, the sensitivity of OES is decreased if polymer is deposited on viewport or the proportion of exposed area on the wafer is too small. To overcome these problems, the endpoint was determined by impedance signal variation from I-V monitoring (VI probe) and self-plasma optical emission spectroscopy. In addition, modified principal component analysis was applied to enhance sensitivity for small area etching. As a result, the sensitivity of this method is increased about twice better than that of OES. From plasma impedance monitoring and self-plasma optical emission spectroscopy, properties of plasma and chamber are analyzed, and real-time endpoint detection is achieved.

  • PDF

Ru 핵생성에 대한 ECR plasma 전처리 세정의 효과 (ECR plasma pretreatment for Ru nucleation enhancement on the TiN film)

  • 엄태종;신경철;최균석;이종무
    • 한국재료학회:학술대회논문집
    • /
    • 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
    • /
    • pp.120-120
    • /
    • 2003
  • MOCVD법으로 TiN 표면에 Ru을 증착함에 있어서 Ru의 핵생성을 고양시키기 위한 ECR plasma 전처리 세정이 필요하다. 본 연구에서는 Ru 증착시 ECR $H_2O$$_2$, AE Plasma 전처리 세정 효과를 SEM, AES, XRD로 분석하였다. Ru의 핵생성은 ECR H$_2$, Ar Plasma의 노출시간이 증가할수록 향상된 반면, ECR $O_2$ plasma의 경우 노출시간이 증가할수록 핵생성 효과는 감소하였다. H$_2$ plasma 내의 H$_2$ion은 Ti와 NH$_3$를 형성하기 위해서 TiN과 반응하여 TiN을 Ti로 개질 시켰으며, Ar plasma 전처리 세정하는 동안 Ar plasma 내의 Ar ion은 TiN 또는 TiON 표면의 질소와 산소원자를 제거하는 효과를 나타내었다. 그 결과 TiN 표면상에서도 Ru의 핵생성이 쉽게 이루어졌으며 H$_2$, Ar ECR Plasma 전처리 세정에서 RU 핵생성이 향상되는 결과를 얻었다. 세 종류의 plasma중에서 Ar ECR plasma로 전처리 세정한 경우에 가장 높은 Ru 핵생성 밀도를 얻을 수 있었다.

  • PDF

$TiO_2$ 반도체 용사피막의 광전극 특성에 미치는 용사조건의 영향 (Effects of Plasma Spray Conditions on Photoelectric Properties of Plasma Sprayed $TiO_2$ Semiconductor)

  • 박정식;박경채
    • Journal of Welding and Joining
    • /
    • 제12권1호
    • /
    • pp.94-101
    • /
    • 1994
  • In this study, plasma spraying has been used to produce $TiO_2$ polycrystalline coatings from $TiO_2$ powders. The physical and chemical properties of plasma sprayed $TiO_2$ coatings depend greatly on plasma spraying conditions. The electrical resistivity, oxygen concentration, photocurrent and crystal structure of plasma sprayed $TiO_2$ coating has been studied. The results are as follows: 1. The oxygen loss and electrical conductivity of $TiO_2$ plasma sprayed coatings increased by low pressure and high amount of auxiliary gas, hydrogen in plasma spraying. 2. Oxygen loss increase electrical conductivity, and decrease photocurrent of $TiO_2$ plasma sprayed coatings. 3. Photocurrent of $TiO_2$ plasma sprayed coatings manufactured in atmospheric pressure is higher than that of low pressure.

  • PDF

Terahertz emission from a plasma dipole oscillation

  • Min Sup Hur;Manoj Kumar;Hyung Seon Song;Teyoun Kang
    • Journal of the Korean Physical Society
    • /
    • 제80권
    • /
    • pp.852-858
    • /
    • 2022
  • We studied an unrevealed characteristic of radiation emission from a localized plasma oscillator (plasma dipole oscillation-PDO). PDO is a novel concept of generating terahertz emission from a laser plasma-based system. The electromagnetic field generated by a PDO embedded in a uniform plasma, instead of being cut off by the ambient plasma as expected by a common but misleading sense, propagates long distances to escape the plasma eventually. The PDO-THz, differently from other laser plasma-based THz sources, utilizes the collective behavior of the plasma (plasma oscillations) and, accordingly, produces a quasi-narrow-band emission, which can potentially be useful in THz-based accelerator or THz-pump and probe experiments. We verified the PDO mechanism by using realistic three-dimensional particle-in-cell simulations.

Study on Validity of 1-D Spherical Model on Aqua-plasma Power Estimation With Electrode Structure

  • 윤성영;장윤창;김곤호
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
    • /
    • pp.74-74
    • /
    • 2010
  • The aqua-plasma is the non-thermal plasma in electrical conductive electrolyte by generates the vapor film layer on the immersed metal electrode surface. This plasma can generate the hydroxyl radical by dissociate the water molecule with the plasma electron. To develop the plasma discharge device for high efficiency in the hydroxyl radical generation, proper model for estimation of plasma power is necessary. In this work, the 1-D spherical model was developed, considering temperature dependence material constants. The relation between the plasma power and hydroxyl generation was also studied by the comparison between the optical emission intensity from the hydroxyl radical using monochromator and estimated plasma power. First, the thickness of vapor layer thickness was estimated using the Navier-Stokes fluid equation in order to calculate the discharge E-field inside vapor layer. Using the E-field magnitude and power balance on the plasma generation, it was possible to estimate the plasma power. The plasma power was assumed to uniformly fill the vapor layer and the temperature of vapor layer was fixed in the boiling temperature of electrolyte, 375K. In the experiment, the aqua-plasma was discharged in the saline by applied the voltage on the bipolar electrode. The range of applied voltage was 234 to 280V-rms in the frequency of 380 kHz. Two type electrodes were produced with two ${\Phi}0.2$ tungsten. The plasma power was estimated from the V-I signal from the two high voltage probes and current probe. The estimated plasma power agreed with the profile of emission intensity when the plasma discharged between the metal electrode and vapor layer surface. However, when the plasma discharged between the metal electrodes, the increasing rate of emission intensity was lower than the increase of plasma power. It implies that the surface reaction is more sufficient rather than the volume reaction in the radical generation, due to the high density of water molecule in the liquid.

  • PDF

Analysis of Biological Effect of DBD-type Non-thermal Atmospheric Pressure Plasma on Saccharomyces Cerevisiae

  • Park, Gyung-Soon;Baik, Ku-Yeon;Kim, Jung-Gil;Kim, Yun-Jung;Lee, Kyung-Ae;Choi, Eun-Ha;Uhm, Hwan-Sup;Jung, Ran-Ju;Cho, Kwang-Sup
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
    • /
    • pp.337-337
    • /
    • 2011
  • Application of plasma technology on microbial sterilization has been frequently studied. In spite of accumulating number of studies, many have been focused on bacteria. Reports on eukaryotic yeasts and filamentous fungi are limited. In addition, mechanism of plasma effect still needs to be clarified. In this study, we analyzed the effect of non-thermal atmospheric pressure plasma on the budding yeast, Saccharomyces cerevisiae using DBD-type device. When yeast cells were exposed to plasma (at 2 mm distance) and then cultured on YPD-agar plate, number of cells survived (shown as colony) were reduced proportionally to exposure time. More than 50% reduction in number of colonies were observed after twice exposure of 5min. each. Colonies much smaller than those of control (no plasma exposure) were appeared after twice exposure of 5 min. each. It seems that small colonies are resulted from delayed cell growth due to the damage caused by plasma treatment. Microscopic analysis demonstrates that yeast cells treated with plasma for 5 min. twice have more rough and shrinked shape compared to oval shape with smooth surface of control.

  • PDF

Curing of meat batter by indirect treatment of atmospheric pressure cold plasma

  • Jo, Kyung;Lee, Juri;Lim, Yubong;Hwang, Jaejun;Jung, Samooel
    • 농업과학연구
    • /
    • 제45권1호
    • /
    • pp.94-104
    • /
    • 2018
  • Nitrite is an essential additive for cured meat product. Plasma is ionized gas and reactive nitrogen species in plasma can be infused into meat batter and subsequently generate nitrites by reaction with water molecules after plasma treatment. However, the increase of nitrite in meat batter is limited with direct treatment of atmospheric pressure cold plasma because of the increase of meat batter temperature. Therefore, this study investigated the influence of indirect treatment of atmospheric pressure cold plasma on the physicochemical properties of meat batter. Meat batter was indirectly treated with plasma at 1.5 kW for 60 min. The pH of meat batter decreased while the temperature increased with plasma treatment time. The total aerobic bacterial count of meat batter was not affected by plasma treatment. The nitrite content of meat batter was increased to 377.68 mg/kg after 60 min of plasma treatment. The residual nitrite content of cooked meat batter also increased with plasma treatment time. The CIE $a^*$-value of cooked meat batter increased. As plasma treatment time increased, lipid oxidation tended to increase and protein oxidation significantly increased. According to these results, the indirect treatment of atmospheric pressure cold plasma can be used as a new curing method for replacing synthetic nitrite salts.

Activation of melanogenesis by non-thermal atmospheric pressure plasma

  • Ali, Anser;Kumar, Naresh;Kumar, Ajeet;Rhee, Prof. Myungchull;Lee, SeungHyun;Attri, Pankaj;Choi, Eun Ha
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
    • /
    • pp.211.1-211.1
    • /
    • 2016
  • Several reports have demonstrated the wide range of nonthermal plasma applications in biomedical field including cancers, diabetics, wound healing and cosmetics. Recently, it has been shown that plasma is able to modulate the p38 MAPK and JUN level in cells which has a crucial role in melanin synthesis and skin pigmentation. Therefore we investigated the effect of plasma on melanogenesis in-vitro using melanoma (B16F10) cells and in-vivo using mouse and zebra fish. To investigate the mechanism of plasma action, plasma device characteristics were measured, reactive species inside and outside the cells were detected, and western blot was performed to find the signaling pathway involved in melanin activation in-vitro and in-vivo. This is the first report presenting the role of nonthermal plasma for melanogenesis which provides a new perspective of plasma in the field of dermatology.

  • PDF

Influence of constraint MgO deposition onto phosphors on luminance properties in AC Plasma Display Panels

  • Jeoung, Jin-Man;OH, P.Y.;Moon, M.W.;Lee, J.H.;Jeong, J.E.;Lee, H.J.;Han, Y.K.;Lee, S.B.;Jeong, S.H.;Yoo, C.K.;Yoo, N.R.;Choi, E.H.;Ko, B.D.
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
    • /
    • pp.1215-1217
    • /
    • 2005
  • One of the important problems in recent AC-PDP technology is the image sticking. In this research, we have investigated the PDP cell with constraint deposition MgO on phosphor, the electrical and optical properties in the PDP cell were examined. Also, we have investigated the correlation with image sticking and degraded MgO protective layer, phosphor in AC-PDP. As a result, we measured the secondary electron emission coefficient ${\gamma}$, discharge characteristics and Brightness for the constraint degraded phosphor are compared with those of nondegraded phosphor.

  • PDF