• 한국진공학회지
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• 제6권1호
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• pp.91-96
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• 1997

평면형 유도 결합 플라즈마의 전기적 특성을 측정하였고 Langmuir probe를 이용하 여 전자의 밀도와 온도를 측정하였다. 코일과 플라즈마를 포함한 총 부하의 저항 성분은 1 에서 4$\Omega$까지 변하였고 인덕턱스는 $1.5\mu$H와 2$\mu$H사이의 값을 가졌다. $10^{11}/\textrm{cm}^3$ 이상의 고밀 도 플라즈마를 발생시켰으며 전자의 온도는 공정 조건에 따라 3에서 5eV까지 변하였다. 산 화막 식각시 선택도를 개선하기 위한 방법으로 바이어스 전압을 변조하는 방법을 모색하였 다. C4F8플라즈마에서 바이어스 변조 방법을 사용하였을 때 선택도는 크게 향상 되었으나 산화막 식각율이 400$\AA$/min 이하였다. 선택도 향상을 위해 수소를 첨가한 실험에서 $C_4F_8$ 플 라즈마에 60% $H_2$를 첨가하였을 때 선택도 50이상, 산화막 식각율 2000$\AA$/min 이상의 결과 를 얻을 수 있었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1998년도 제17회 KOSCI SYMPOSIUM 논문집
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• pp.31-36
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• 1998

An experimental study has been performed to characterize fundamental aspects of VOCs removal using non-thermal palsma technique. The removed VOCs in the present study are toluene ($C_6H_5CH_3$), ethene ($C_2H_4$), propene ($C_3H_6$) which are typical air pollutants generated from industry and automobile engines. The non-thermal plasma used in the present experiments has been produced in a wire-cylinder reactor with pulsed corona or a packed-bed reactor filled with ceramic bead. These differently generated non-thermal plasma have been visualized with an intensified CCD. The images of non-thermal plasma have been used for optimal design of a corona reactor used in the present study. The experimental results show that the removal efficiencies of VOCs with non-thermal plasma are dependant on the reactivity of VOCs with OH, O, and $O_3$. The results also show that the removal efficiencies of VOCs decrease significantly when VOCs are treated with NO that is also oxidized in the presence of OH, O, and $O_3$.

• 한국표면공학회지
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• 제34권5호
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• pp.403-408
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• 2001

In this work, the cyclic perfluorinated ether (c-C$_4$F$_{8}$O) with very high destructive removal efficiency (DRE) than other alternative gases, such as $C_3$F$_{8}$, c-C$_4$F$_{8}$ and NF$_3$ was used as an alternative process chemical. The plasma cleaning of silicon nitride using gas mixtures of c-C$_4$F$_{8}$O/O$_2$ and c-C$_4$F$_{8}$O/O$_2$+ $N_2$ was investigated in order to evaluate the effects of adding $N_2$ to c-C$_4$F$_{8}$O/O$_2$ on the global warming effects. Under optimum condition, the emitted net perfluorocompounds (PFCs) during cleaning of silicon nitride were quantified and then the effects of additive $N_2$ by obtaining the destructive removal efficiency (DRE) and the million metric tons of carbon equivalent (MMT-CE) were calculated. DRE and MMTCE were obtained by evaluating the volumetric emission using. Fourier transform-infrared spectroscopy (FT-IR). During the cleaning using c-C$_4$F$_{8}$O/O$_2$+$N_2$, DRE values as high as (equation omitted) 98% were obtained and MMTCE values were reduced by as high as 70% compared to the case of $C_2$F$_{6}$O$_2$. Recombination characteristics were indirectly investigated by combining the measurements of species in the chamber using optical emission spectroscopy (OES), before and after the cleaning, in order to understand any correlation between plasma and emission characteristics as well as cleaning rate of silicon nitride.silicon nitride.

• 한국식품조리과학회지
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• 제16권6호
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• pp.644-651
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• 2000

This study was carried out to evaluate the effects of fractions of methanol(MeOH) extracts of Lycopus lucidic Turcz on hyperglycemia and energy metabolites in streptozotocin(STZ) diabetic rats. Diabetes mellitus was induced in male Sprague-Dawley rats weighing 200-220 g by an injection of STZ dissolved in a citrate buffer into the tail vein at a dose of 45 mg/kg of body weight, and the rats were divided into 7 groups, that is, one normal group and 6 diabetic groups: STZ-control, hexane, chloroform(CHCl$\sub$3/). ethylacetate(EtOAc), butanol(BuOH) and H$\sub$2/O fraction-fed groups. All groups were fed an AIN-93 diet and the fractions of Lycopus lucidic Turcz were administered orally with 2 % Tween 80 for 14 days after the STZ injection. Body weight, diet intake and organ weights were monitored. The plasma levels of blood glucose, insulin and protein were determined. The plasma concentrations of cholesterol, HDL-cholesterol, triglycerides and free fatty acid were assayed. The plasma activities of aspartate aminotransferase (AST) and alanine aminotransferase(ALT) were also measured. Body weight losses were observed by feeding the fractions of Lycopus lucidic Turcz in STZ experimental groups, and the kidney weight was increased. The extent of blood glucose decrement was significantly greater in the hexane and BuOH fraction-fed groups than STZ-control group. The plasma protein level was significantly lower in the H$\sub$2/O fraction-fed group. The plasma cholesterol level was decreased in BuOH and H$\sub$2/O fraction-fed groups compared with the STZ-control group. The levels of free fatty acids in the CHC1$\sub$3/ and H$\sub$2/O fraction-fed groups were significantly decreased(p<0.05). ALT activitiy of BuOH fraction-fed group was lower than control but it was not significantly different. These results suggest that the fractions of Lycopus lucidic Turcz are capable of lowering blood glucose and fat metabolites concentrations when administered to STZ-treated rats, and AST/ALT activity and insulin levels show the possibility of therapeutic use to diabetes mellitus.

• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.360-368
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• 1999

The paper describes spectroscopic characteristics of plasma induced in the pulsed YAG laser welding of alloys containing a large amount of volatile elements. The authors have conducted the spectroscopic analyses of laser induced Al-Mg alloys plasma in the air and argon atmosphere. In the air environment the identified spectra were atomic lines of Al, Mg, Cr, Mn, Cu, Fe and Zn and singly ionized Mg lines as well as the intense molecular spectra of ALO and MgO formed by chemi-cal reactions of evaporated Al and Mg atoms from the pool surface with oxygen in the air. In argon atmosphere MgO and AlO spectra vanished but AlH spectrum was detected. the hydrogen source was presumable hydrogen dissolved in the base metals water absorbed on the surface oxide layer or $H_2$ and $H_2O$ in the shielding gas. The resonant lines of Al and Mg were strongly self-absorbed in particular self-absorption of the Mg line was predominant. These results show that the laser induced plasma was made of metallic vapor with relatively low temperature and high density.

• The Korean Journal of Physiology and Pharmacology
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• 제22권2호
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• pp.215-223
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• 2018

Intracellular $Ca^{2+}$ mobilization is closely linked with the initiation of salivary secretion in parotid acinar cells. Reactive oxygen species (ROS) are known to be related to a variety of oxidative stress-induced cellular disorders and believed to be involved in salivary impairments. In this study, we investigated the underlying mechanism of hydrogen peroxide ($H_2O_2$) on cytosolic $Ca^{2+}$ accumulation in mouse parotid acinar cells. Intracellular $Ca^{2+}$ levels were slowly elevated when $1mM\;H_2O_2$ was perfused in the presence of normal extracellular $Ca^{2+}$. In a $Ca^{2+}-free$ medium, $1mM\;H_2O_2$ still enhanced the intracellular $Ca^{2+}$ level. $Ca^{2+}$ entry tested using manganese quenching technique was not affected by perfusion of $1mM\;H_2O_2$. On the other hand, $10mM\;H_2O_2$ induced more rapid $Ca^{2+}$ accumulation and facilitated $Ca^{2+}$ entry from extracellular fluid. $Ca^{2+}$ refill into intracellular $Ca^{2+}$ store and inositol 1,4,5-trisphosphate ($1{\mu}M$)-induced $Ca^{2+}$ release from $Ca^{2+}$ store was not affected by $1mM\;H_2O_2$ in permeabilized cells. $Ca^{2+}$ efflux through plasma membrane $Ca^{2+}-ATPase$ (PMCA) was markedly blocked by $1mM\;H_2O_2$ in thapsigargin-treated intact acinar cells. Antioxidants, either catalase or dithiothreitol, completely protected $H_2O_2-induced$ $Ca^{2+}$ accumulation through PMCA inactivation. From the above results, we suggest that excessive production of $H_2O_2$ under pathological conditions may lead to cytosolic $Ca^{2+}$ accumulation and that the primary mechanism of $H_2O_2-induced$ $Ca^{2+}$ accumulation is likely to inhibit $Ca^{2+}$ efflux through PMCA rather than mobilize $Ca^{2+}$ ions from extracellular medium or intracellular stores in mouse parotid acinar cells.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.452-455
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• 2000

Diamond thin films were synthesized on WC-Co substrate at various experimental parameters using 13.56MHz RF PACVD(radio frequency plasma-assisted chemical vapor deposition). In order to increase the nucleation density, the WC-Co substrate was polished with 3$\mu\textrm{m}$ diamond paste. And the WC-Co substrate was pretreated in HNO$_3$: H$_2$O = 1:1 and O$_2$ plasma. In H$_2$-CH$_4$gas mixture, the crystallinity of thin film increased with decreasing CH$_4$concentration at 800W discharge power and 20torr reaction pressure. In H$_2$-CH$_4$-O$_2$gas mixture, the crystallinity of thin film increased with increasing O$_2$concentration at 800W discharge power, 20torr reaction pressure and 4% CH$_4$concentration.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2008년도 제35회 하계학술대회 초록집
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• pp.285-285
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• 2008

• 한국물환경학회지
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• 제30권4호
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• pp.394-402
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• 2014

High-voltage dielectric discharges are an emerging technique in environmental pollutant degradation, which are characterized by the production of hydroxyl radicals as the primary degradation species. The initiation and propagation of the electrical discharges depends on several physical, chemical, and electrical parameters such as 1st and 2nd voltage of power, gas supply, conductivity and pH. These parameters also influence the physical and chemical characteristics of the discharges, including the production of reactive species such as OH, $H_2O_2$ and $O_3$. The experimental results showed that the optimum 1st voltage and oxygen flow rate for RNO (N-Dimethyl-4-nitrosoaniline, indicator of the generation of OH radical) degradation were 160 V (2nd voltage of is 15 kV) and 4 L/min, respectively. As the 2nd voltage (4 kV to 15 kV) was increase, RNO degradation was increased and, generated $H_2O_2$ and $O_3$ concentration were increased. The conductivity of the solution was not influencing the RNO degradation, $H_2O_2$ and $O_3$ generation. The pH effect on RNO degradation was not high. However, the lower pH and the conductivity, the higher $H_2O_2$ and $O_3$ generation were observed.

• 자원리싸이클링
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• 제25권3호
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• pp.49-54
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• 2016

본 연구에서는, 아크 플라즈마 정련을 이용하여 지르콘샌드($ZrSiO_4$)를 지르코니아($ZrO_2$)와 실리카($SiO_2$)로 분리하였다. 실리카를 마이크로웨이브 침출을 통해 제거하고 고순도의 지르코니아를 얻었다. 플라즈마 퓨전은 두 가지 공정을 순차적으로 진행하였다. Ar 100% 분위기에서 환원 공정을 거친 후, Ar-$H_2$ 혼합 가스를 통해 정련과정을 거쳤다. 진공 챔버 내에서 냉각 후 지르코니아와 실리카로 이루어진 고상을 얻었다. 마이크로웨이브 침출을 위해 $240^{\circ}C$, 20% 황산용액을 사용하였다. 분석 결과 고순도(98.6%)의 지르코니아를 얻을 수 있었다.