• Journal of the Semiconductor & Display Technology
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• v.13 no.4
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• pp.1-5
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• 2014

The plasma density distribution in between the electrode and lateral wall of a narrow gap CCP was investigated. The plasma density distribution was obtained using single Langmuir probe, having two peaks of density distribution at the center of electrode and at the peripheral area of electrodes. The plasma density distribution was compared with the RF fluctuation of plasma potential taken from capacitive probe. Ionization reactions obtained from numerical analysis using CFD-$ACE^+$ fluid model based code. The peaks in two region for plasma density and voltage fluctuation have similar spatial distribution according to input power. It was found that plasma density distribution between the electrode and the lateral wall is closely related with the local ionization.

• Journal of the Korean institute of surface engineering
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• v.36 no.1
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• pp.69-73
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• 2003

The atmospheric pressure plasma is regarded as an effective method for surface treatments because it can reduce the period of process and doesn't need expensive vacuum apparatus. The performance of non-transferred plasma torches is significantly depended on jet flow characteristics out of the nozzle. In order to produce the high performance of a torch, the maximum discharge velocity near an annular gap in the torch should be maintained. Also, the compulsory swirl is being produced to gain the shape that can concentrate the plasma at the center of gas flow. In this work, the distribution of gas flow that goes out to atmosphere through a plenum chamber and nozzle is analyzed to evaluate the performance of atmospheric pressure plasma torch which can present the optimum design of the torch. Numerical analysis is carried out with various angles of an inlet flow velocity. Especially, three-dimensional model of the torch is investigated to estimate swirl effect. We also investigate the stabilization of plasma distribution. For analyzing the swirl in the plenum chamber and the flow distribution, FVM (finite volume method) and SIMPLE algorithm are used for solving the governing equations. The standard k-model is used for simulating the turbulence.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.2
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• pp.79-83
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• 2008

In this paper, we introduced a LIF measurement method and summarized the theoretical side. When an altered wavelength of laser and electric power, lamp applied electric power, we measured the relative density of the metastable state in mercury after observing a laser induced fluorescence signal of 404.8nm and 546.2nm, and confirmed the horizontal distribution of plasma density in the discharge lamp. Due to this generation, the extinction of atoms in a metastable state occurred through collision, ionization, and excitation between plasma particles. The density and distribution of the metastable state depended on the energy and density of plasma particles, intensely. This highlights the importance of measuring density distribution in plasma electric discharge mechanism study. The results confirmed the resonance phenomenon regarding the energy level of atoms along a wavelength. change, and also confirmed that the largest fluorescent signal in 436nm, and that the density of atoms in 546.2nm ($6^3S_1{\to}6^3P_2$) were larger than 404.8nm ($6^3S_1{\to}6^3P_2$). According to the increase of lamp applied electric power, plasma density increased, too. When increased with laser electric power, the LIF signal reached a saturation state in more than 2.6mJ. When partial plasma density distribution along a horizontal axis was measured using the laser induced fluorescence method, the density decreased by recombination away from the center.

• Journal of Welding and Joining
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• v.8 no.4
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• pp.58-68
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• 1990

The formation of thermal stresses by plasma spraying is generally considered as adverse. Therefore, the knowledge of stress distribution in the deposited layer during and after plasma spraying will be of special interest. In this study finite difference heat transfer analysis and finite element stress analysis were carried out to predict the change of stress distribution in the plasma coated layer with the variations of preheat temperature, number of scan, particle size, and bond coat. The results of the numerical analysis were as follows: 1) Transient stresses developed in the coated layer were up to the level of yiedl strength at the temperature. 2) The tensile stresses were developed in the deposited layer and the surface of the substrate, but the compressive stresses were developed in the rest of the substrate. 3) Transient and residual stresses were significantly affected by the preheat temperature. 4) The variations of temperature of powder particle and number of torch scan changed tensile stress distribution, but made no difference on the magnitude of the stresses. 5) Bond coated layer reduced the stree level of deposited layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.59-61
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• 2002

In this study we attempted to diagnose the distribution of nitrogen plasma density generated using PECVD(plasma enhanced chemical vapor deposition). The distribution of plasma density formed in a PECVD chamber were measured by DLP2000. The experiment results showed that the plasma density is related to RF power and gas flow rate. As RF power gets higher, the plasma density linearly increased. And the experimental results revealed that a pressure in chamber affects plasma density.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.4
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• pp.82-86
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• 1999

Electron Energy Distribution Function(EEDF) were treasured In Radio-Frequency Inductively Coupled Plasma(RFlCP) using a probe rrethocl Measurerrents were conducted in argon discharge for pressure from 10[mTorr] to 4O[mTorr] and input rf power from 100[W] to 600[W] and flow rate from 3[sccm] to 12[sccm]. Spatial distribution of electron energy distribution function were measured for discharge with same aspoct ratio (R/L=2). Electron energy distribution function strongly depended on both pressure and power. Electron energy distribution function increased with increasing flow rate. Radial distribution of the electron energy distribution function were peaked in the plasma center. Normal distribution of the electron energy distribution function were peaked in the center between quartz plate and substrate. From the results, we can find out the generation mechanism of Radio Frequency Inductively Coupled Plasma. And these results contribute the application of a simple Inductively Coupled Plasma(ICP).a(ICP).

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.461-467
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• 1989

The activity of lactate dehydrogenase in plasma and various tissues(skeletal muscle, cardiac muscle, liver, lung, kidney and spleen) of Korean native cattle in a Chonju abattoir, the Breeding Stock Farm and Animal Farm of Chonbuk University was determined by using ultra violet method. Using polyacrylamide gel electrophoresis, the lactate dehydrogenase isoenzyme distrimution of plasma and various tissues in Korean native cattle was studied. The plasma lactate dehydrogenase activity of Korean native cattle was $554.80{\pm}92.70IU/l$ and the lactate dehydrogenase activity of male plasma was $543.96{\pm}97.89IU/l$, which was lower than that of female plasma, $579.19{\pm}78.09IU/l$. The plasma lactate dehydrogenase activity of calf was $557.31{\pm}110.27IU/l$ and was no significantly different from that of adult Korean native cattle. But the range of calf lactate dehydrogenase activity was larger than that of adult Korean native cattle. In tissues, the lactate dehydrogenase activity was decreased in order of lung, kidney, spleen, liver, heart and skeletal muscle. The lung had the greatest activity and the skeletal muscle had the least. Lactate dehydrogenase isoenzymes in plasma and tissues were found to have a characteristic distribution and quantitative isoenzyme patterns. In plasma, the LDH1 usually had the greatest activity and other isoenzymes showed a decreasing tendency in order of LDH2, LDH3, LDH4 and LDH5. The distribution of lactate dehydrogenase isoenzymes had a wide variation in tissues. But the distribution of LDH isoenzymes in plasma was similar to that in kidney, and also cardiac muscle and spleen had similar pattern in LDH isoenzymes distribution.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1998.11a
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• pp.131-133
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• 1998

Electron temperature, electron density and electron energy distribution function were measured in Radio-Frequency Inductively Coupled Plasma(RFICP) using a probe method. Measurements were conducted in argon discharge for pressure from 10 mTorr to 40 mTorr and input rF power from 100W to 600W and flow rate from 3 sccm to 12 sccm. Spatial distribution of electron temperature, electron density and electron energy distribution function were measured for discharge with same aspect ratio (R/L=2). Electron temperature was found to depend on pressure, but only weakly on power. Electron density and electron energy distribution function strongly depended on both pressure and power. Electron density and electron energy distribution function increased with increasing flow rate. Radial distribution of the electron density and electron energy distribution function were peaked in the plasma center. Normal distribution of the electron density, electron energy distribution function were peaked in the center between quartz plate and substrate. These results were compared to a simple model of ICP, finally, we found out the generation mechanism of Radio-Frequency Inductively Coupled Plasma.

• Journal of the Semiconductor & Display Technology
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• v.17 no.1
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• pp.76-83
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• 2018

The electron energy probability function (EEPF) is of significant importance since the plasma chemistry such as the rate of ionization is determined by the electron energy distribution function. It is usually assumed to be Maxwell distribution for 0-D global model. Meanwhile, it has been observed experimentally that the form of EEPF of Ar plasma changes from being two-temperature to Druyvesteyn like as the gas pressure increases. Thus, to apply the 0-D global model of Maxwellian distribution to the non-Maxwellian plasma, we investigated the relative contribution of two distinct electrons with different temperatures. The contributions of cold/hot electrons to the equilibrium state of the plasma have attracted interest and been researched. The contributions to the power and particle balance of cold/hot electrons were studied by comparing the result of the global model considering all combinations of electron temperatures with that of 1-D Particle-in-Cell and Monte Carlo collision (PIC-MCC) simulation and the results of studies were analyzed physically. Furthermore, comparisons term by term for variations of the contribution of cold/hot electrons at different driving currents are presented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.7
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• pp.1211-1217
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• 2016

Discharge characteristics of inductively coupled plasma were investigated by using electrostatic probe and fluid simulation. The Inductively Coupled Plasma source driven by 13.56 Mhz was prepared. The signal attenuation ratios of the electrostatic probe at first and second harmonic frequency was tuned in 13.56Mhz and 27.12Mhz respectively. Electron temperature, electron density, plasma potential, electron energy distribution function and electron energy probability function were investigated by using the electrostatic probe. Experiment results were compared with the fluid simulation results. Ar plasma fluid simulations including Navier-Stokes equations were calculated under the same experiment conditions, and the dependencies of plasma parameters on process parameters were well agreed with simulation results. Because of the reason that the more collision happens in high pressure condition, plasma potential and electron temperature got lower as the pressure was higher and the input power was higher, but Electron density was higher under the same condition. Due to the same reason, the electron energy distribution was widening as the pressure was lower. And the electron density was higher, as close to the gas inlet place. It was found that gas flow field significantly affect to spatial distribution of electron density and temperature.