• Journal of Nutrition and Health
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• v.35 no.1
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• pp.30-36
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• 2002

This study was conducted to evaluate the effect of regular exercise and other relating factors on the activities of erythrocyte antioxidant enzymes and plasma total radical-trapping antioxidant potential (TRAP) in 61 healthy male college students. The study population were divided in two groups ; small amount of exerciser (exorcise time less than 30min/d) and moderate amount of exerciser (exorcise time more than 30min/d) according to their physical exercise habits measured by a questionnaire. Dietary intake of vitamin C and vitamin E, Plasma lipid Profiles, erythrocyte superoxide dismutase(SOD), glutathione peroxidase(GSH-Px) and catalase activities, as well as plasma TRAP levels were determined. Plasma TRAP level was significantly higher in moderate amount of exercisers than that in small amount of exercisers. No significant differences were observed in erythrocryte SOD, catalase and GSH-Px between the two groups. Mean exercise time was positively correlated with the plasma level of TRAP significantly, and amount of alcohol consumption was negatively correlated with the erythrocyte SOD activity, Dietary vitamin C and I intakes did not correlated with either erythrocyte enzyme activities or plasma TRAP levels. There were positive correlations between plasma HDL-cholesterol, and erythrocyte GSH-Px or plasma TRAP levels. Plasma vitamin C concentrations was negatively correlated with plasma TRAP levels and erythrocyte SOD activity, however plasma vitamin C concentration was positively correlated with erythrocyte GSH-Px activity, The results would suggest that regular moderate exercise, nonsmoking, high HDL-cholesterol and high plasma vitamin E concentration enhance antioxidant defences against reactive oxygen species and may increase the likelihood of a healthier life span.

• Journal of Nutrition and Health
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• v.30 no.10
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• pp.1180-1187
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• 1997

Cigarette smoking is a major risk factor of atherosclerosis and has been reported to contain an abundance of free radical species which could be expected to deplete antioxidants such as vitamin C . The present study was designed to investigate the relationship between smoking, plasma lipid and lipoprotein concentration, and plasma vitamin C level. Fifty-five healthy male smokers and 32 non-smokers were investigated in the study. Mean age, body weight , BMI and blood pressure made no differences in both smokers and non-smokers. Significantly, smokers has higher plasma total cholesterol and LDL-C , and lower HDL-C /LDL-C ratio compared with non-smokers. Plasma level of thiobartiturin acid reactive substances(TBARS), indicator of lipid peroxidation and increased susceptibility of LDL towards lipid perosidation, were elevated in smokers(p<0.001), while the plasma vitamin C level of smokers was significantly lower than that of non-smokers(p<0.05), indicating that elevated lipid peroxidation are associated with decreased plasma vitamin C content. In non-smokers a significantly positive correlation was observed between dietary vitamin C intake and plasma levels, but no such association observed in smokers. Lack of such a relationship and the decreased plasma vitamin C level in the smokers suggest that smoking may cause increased turnover of the plasma antioxidant. Consuquently, the sustained free radical load derived from smoking causes an imbalance in oxidant/antioxidant status and it could be expected that cigarette smoking renders plasma LDL more susceptible to oxidative modification . In the present study the possible explanations for that cigarette smokers have a higher risk of cardiovascular disease include the changes of blood lipid and lipoprotein concentration, and plasma vitamin C status which might have protective functions against free radicals -medaited lipid peroxidation.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.906-909
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• 2006

The secondary electron emission coefficient $({\gamma})$ of the cathode is an important factor for improving the discharge characteristics of AC-PDPs because of its close relationship to discharge voltage. In AC-PDPs, MgO is most widely used as a surface protective layer. In this experimental, we have investigated the electronic structure of the energy band structure of the MgO layer responsible for the high ${\gamma}$. The MgO layers have been deposited by electron beam evaporation method, where the $O_2$ partial pressures have been varied as 0, $5.2{\times}10^{-5}$ torr, $1.0{\times}10^{-4}$ torr, and $4.1{\times}10^{-4}$ torr, in this experiment. It is noted that work function that is energy gap between surface and first defect level of MgO layer has the lowest value for the highest O2 partial pressure of $4.1^{\ast}10^{-4}$ Torr.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1207-1210
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• 2005

The MgO protective layer provides protection from the discharge, lowers the discharge voltage and prolongs the AC-PDP lifetime. We have investigated the characteristics of degradation of MgO protective layer, which correlates to the image-sticking[1] and the lifetime in AC-PDP. The degraded MgO have been changed the surface morphology of MgO. It was found that panel lifetime depended on degradation of MgO protective.

• Journal of the Korea Fashion and Costume Design Association
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• v.10 no.3
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• pp.173-180
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• 2008

Cotton, wool, cotton/wool blended (80:20) and tencel fabrics were treated with low temperature oxygen plasma, enzymes (cellulase or protease), or oxygen plasma-enzyme and they were examined for dyeing and handling properties for environment friendly finishing. The appropriate conditions for cellulase treatment were enzyme concentration of 3g/l, pH of 5, and $60^{\circ}C$ for one hour, and for protease treatment were enzyme concentration of 4g/l, pH of 8, and $60^{\circ}C$ for one hour. The equilibrium uptake of a direct dye on cotton changed with plasma treatment and plasma-cellulase treatment, and the rate of dyeing slightly decreased. When wool was dyed with acid dye, the equilibrium dye uptake did not change with plasma, protease treatment nor plasma-protease treatment, however, the rate of dyeing had increased with plasma-protease treatment. From these results, it is assumed that plasma attacks the surface of the fiber, and enzyme mainly affects the inner part of the fiber. Plasma treatment did not affect mechanical properties related to the handling of fabrics. The handling test showed increased extension at maxmum load(EM), tensile energy(WT) with decreased tensile resilience (RT), and the fabrics became softer but resilience decreased slightly with enzyme treatment. The bending recidity(B), hysteresis of bending moment(2HB), and hysteresis of shear force at five degrees(2HG5) decreased, however, shear stiffness(G) increased. I knew the plasma pre-treatment made fabrics softer with lower koshi(stiffness). The handling of plasma pre-treated fabrics was better than that of enzyme-treated fabrics. When we pre-treated fabrics, the handling test showed decreased coefficient of friction(MIU), geometrical roughness(SMD), while the surface of fabrics became smoother and numeri increased. Even though compression resilience(RC) increased, fukurami(bulky property) and compressive elasticity, decreased due to the linearity of compression-thickness curve(LC) and compression energy(WC).

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.247.1-247.1
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• 2014

The capacitive coupled plasma is used widely in the semiconductor industries. Especially, the uniformity of the industrial plasma is heavily related with defect ratio of devices. Therefore, the industries need the capacitive coupled plasma source which can generate the uniform plasma and control the plasma's uniformity. To achieving the uniformity of the large area plasma, we designed multi-powered electrodes. We controlled the uniformity by controlling the power of each electrode. After this work, we started to research another concept of the plasma device. We make the plasma chamber that has multi-ground electrodes imaginary (CST microwave studio) and simulate the electric field. The shape of the multi-ground electrodes is ring type, and it is same as the shape of the multi-power electrodes that we researched before. The diameter of the side electrode's edge is 300mm. We assumed that the plasma uniformity is related with the impedance of ground electrodes. Therefore we simulated the imaginary chamber in three cases. First, we connected L (inductor) and C (capacitor) at the center of multi-ground electrodes. Second, we changed electric conductivity of multi-ground electrode. Third, we changed the insulator's thickness between the center ground electrode and the side ground electrode. The driving frequency is 2, 13.56 and 100 MHz. We switched our multi-powered electrode system to multi-ground electrode system. After switching, we measured the plasma uniformity after installing a variable vacuum capacitor at the ground line. We investigate the effect of ground electrodes' impedance to plasma uniformity.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.332-332
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• 2011

The extreme ultraviolet (EUV) radiation, whose wavelength is from 120 nm down to 10 nm, and the energy from 10 eV up to 124 eV, is widely utilized such as in photoelectron spectroscopy, solar imaging, especially in lithography and soft x-ray microscopy. In this study, we have investigated the plasma diagnostics as well as the debris characteristics between the two types of dense plasma focusing devices with coaxial electrodes of Mather and hypocycloidal pinch (HCP), respectively. The EUV emission intensity, electron temperature and plasma density have been investigated in these cylindrical focused plasma along with the debris characteristics. An input voltage of 5 kV has been applied to the capacitor bank of 1.53 uF and the diode chamber has been filled with Ar gas at pressure ranged from 1 mTorr and 180 mTorr. The inner surface of the cathode was covered by polyacetal insulator. The central anode electrode has been made of tin. The wavelength of the EUV emission has been measured to be in the range of 6~16 nm by a photo-detector (AXUV-100 Zr/C, IRD). The visible emission has also been measured by the spectrometer with the wavelength range of 200~1,100 nm. The electron temperature and plasma density have been measured by the Boltzmann plot and Stark broadening methods, respectively, under the assumption of local thermodynamic equilibrium (LTE).

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.1
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• pp.78-82
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• 2014

Power Transformers with more than one secondary winding are not uncommon in industrial applications. But new classes of applications where very large number of independent secondaries are used are becoming popular in controlled converters for medium and high voltage applications. Cascade H-bridge medium voltage drives and Pulse Step Modulation (PSM) based high voltage power supplies are such applications. Regulated high voltage power supplies (Fig. 1) with 35-100 kV, 5-10 MW output range with very fast dynamics (${\mu}S$ order) uses such transformers. Such power supplies are widely used in fusion research. Here series connection of isolated voltage sources with conventional switching semiconductor devices is achieved by large number of separate transformers or by single unit of multi-secondary transformer. Naturally, a transformer having numbers of secondary windings (~40) on single core is the preferred solution due to space and cost considerations. For design and simulation analysis of such a power supply, the model of a multi-secondary transformer poses special problem to any circuit analysis software as many simulation softwares provide transformer models with limited number (3-6) of secondary windings. Multi-Secondary transformer models with 3 different schemes are available. A comparison of test results from a practical Multi-secondary transformer with a simulation model using magnetic component is found to describe the behavior closer to observed test results. Earlier models assumed magnetising inductance in a linear loss less core model although in actual it is saturable core made-up of CRGO steel laminations. This article discusses a more detailed representation of flux coupled magnetic model with saturable core properties to simulate actual transformers very close to its observed parameters in test and actual usage.

• Journal of IKEEE
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• v.28 no.1
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• pp.38-45
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• 2024

Most previous works about magnetic effect on plasma emission were interested in emission enhancement which was useful to various fields of plasma application. On the contrary, the following work is interested in plasma dissipation rarely reported in prior researches and expected to help advance plasma-controlling technique. Nd:YAG laser (1064 nm, 6 ns) was focused on three kinds of metals (Al, Ti and STS) and air. The permanent magnetic field (0.4 T) of Nd₂Fe₁₄B magnet was provided passing throughout laser-induced plasma. The spectra of plasma in both the presence and absence of the magnetic field were observed with varying laser power and delay time of the spectrograph. In this work it was uniquely discovered that the plasma always dissipated easily in the presence of magnetic field irrespective of the laser power. With the O I(777.42 nm)-line shape function fitted to Lorentz profile, its half width at half maximum (HWHM) was evaluated to verify that the magnetic field increased the plasma density. It is concluded that magnetic field facilitates not only plasma emission enhancement but also plasma dissipation, increasing recombination rate which is proportional to plasma density.

• Journal of the Korean institute of surface engineering
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• v.42 no.5
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• pp.208-215
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• 2009

We employed atmospheric plasma to reactively remove the lubricant sprayed onto such industrial electronic parts as LCD chassis during sheet-metal forming processes and investigated basically the effect of plasma parameters on cleansing the surfaces of zinc-electroplated steel plates (EGI). Specimen prepared with some controlled amount of lubricant sprayed on their surfaces beforehand were subjected to two different kinds of atmospheric plasma, one being generated by using air and the other generated by using nitrogen (99.9% purity). Locating the plasma beams at the height range between 3.5 and 13.5 mm from the surface of each specimen and radiating for 5 to 30 seconds resulted out that the cases with a position of 3.5 mm and a duration of 5 seconds or longer showed the surfaces completely cleansed without a trace of lubricant. Furthermore we found out that the plasma generated by using simple air depicted higher cleansing ability than the other one generated by using expensive nitrogen, interestingly useful very much for industrial purposes. On another aspect, we confirmed that the drilled or cut surfaces of Zn-plated steel substrate would not be oxidized even under the influence of plasma during its cleansing process. Therefore, we could probably conclude from this fore-survey that a dry process adopting atmospheric plasma for cleansing industrial parts might be determined to become successful in terms of commercialization, cautiously.