• Korean journal of food and cookery science
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• v.13 no.1
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• pp.23-29
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• 1997

The hypoglycemic effect of fractions of methanol extract of Cassia tora was investigated in diabetic rats. Sprague-Dawley male rats weighing 180∼230 g were divided into 6 groups. Diabetes was induced in the male rats by intravenous injection of streptozotocin at a dose of 45 mg/kg dissolved in citrate buffer (pH 4.5). The diabetic animals then had plasma glucose concentration of above 300 mg/㎗. Fractions of methanol extract of Cassia tora were administered orally into the diabetic rats for 14 days after streptozotocin injection. The food intake and body weight gain were monitored and plasma levels of glucose, triglyceride, free fatty acid, HDL-cholesterol, cholesterol and ALT activity were determined. Levels of glycogen, cholesterol and triglyceride in liver were analysed. Weights of liver and kidney were lighter in all the fraction-administered groups than streptozotocin-control group. Plasma glucose level was significantly decreased by the administration of butanol fraction at 14 days. Plasma triglyceride levels were lower in chloroform, butanol and H$_2$O fraction-administered groups compared to streptozotocin-control group. Plasma cholesterol and HDL-cholesterol levels were not significantly different in all groups. Administrations of each of the four fractions have decreased plasma free fatty acid level, ALT activity and liver triglyceride levels in the diabetic rats. Liver glycogen levels in chloroform, butanol and H$_2$O fraction-administered groups were higher than streptozotocin-control group. It is suggested from the results that butanol fraction of methanol extract of Cassia tora may contain the antihyperglycemic compounds.

• Journal of the Korean Society of Combustion
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• v.13 no.4
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• pp.47-53
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• 2008

The reaction mechanism of methane dry reforming has been investigated using an arc-jet reactor. The effects of input power, $CO_2/CH_4$ and added $O_2$ were investigated by product analysis, including CO, $H_2$, $C_{2}H_{Y}$ and $C_{3}H_{Y}$ as well as $CH_4$ and $CO_2$. In the process, input electrical power activated the reactions between $CH_4$ and $CO_2$ significantly. The increased feed ratio of the $CO_2$ to $CH_4$ in the dry reforming does not affect to the $CH_4$ conversion. but we could observe increase in CO selectivity together with decreasing $H_2$ generation. Added oxygen can also increase not only CO selectivity but also $CH_4$ conversion. However, hydrogen selectivity was decreased significantly due to a increased $H_{2}O$ formation.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.96-102
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• 2001

plasma-sprayed Cr$_2$O$_3$-based coatings containing MoO$_3$ were studied to gain a better understanding of the influence of MoO$_3$ composition in the coatings on their tribological behaviour. A reciprocal type tribo-tester was employed to examine friction and wear behavior of the specimens at high temperature(450。C). The physical characteristics of worn surfaces were investigated by scanning electron microscopy and chemical composition of the coating surfaces was analyzed using a X-ray photoelectron spectrometer. The results showed that friction coefficient of the MoO$_3$-added coatings were lower than those without MoO$_3$ addition. The larger protecting layers were observed at the worn surface of plasma spray coated specimens with MoO$_3$ addition. XPS analysis of the protecting layer indicated that MoO$_3$ composition was dominantly formed at the surface. MoO$_3$ composition in the protecting layer appears to be more favorable in reducing the friction.

• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.296-301
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• 2009

An inductively coupled plasma assisted atomic layer deposition(ICP-ALD) system has been constructed for the deposition of ZnO thin films, and various experiments of ZnO thin films on p-type Si(100) substrates have been carried out to find the self-limiting reaction conditions for the ICP-ALD system under non-plasma circumstances. Diethyl zinc[$Zn(C_2H_5)_2$, DEZn] was used as the zinc precursor, $H_2O$ as the oxidant, and Ar as the carrier and purge gas. At the substrate temperature of $150^{\circ}C$, atomic layer deposition conditions based on self-limiting surface reaction were successfully obtained by series of experiments through the variation of exposure times for DEZn, $H_2O$, and Ar. ZnO deposition was repeated at different substrate temperatures of $90{\sim}210^{\circ}C$. As a result, the thermal process window(ALD window) for ZnO thin films was observed to be $110{\sim}190^{\circ}C$ and the average growth rate was measured to be constant of 0.29 nm/cycle. Properties of the film's microstructure and composition(Zn, O, etc.) were also studied. As the substrate temperature increases, the crystallinity was improved and ZnO(002) peak became dominant. The films deposited at all temperatures were high purity, and the films deposited at high temperatures had the composition ratio between Zn and O closer to one of a stable hexagonal wurtzite structure.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1254-1257
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• 2004

Comparative study on the effects of $H_2$ vs. $O_2$ plasma pretreatment of gate oxide on the degradation phenomenon of p-channel low-temperature polysilicon (LTPS) thin-film transistors (TFTs) were performed. After high drain current stress (HDCS) with $V_{gs}$ = $V_{ds}$, the p-channel TFTs pretreated by $O_2$ plasma showed increased immunity to the degradation of device characteristics such as threshold voltage and maximum field effect mobility because of the higher binding energy of Si-O bond than that of Si-H bond. The investigation of degradation phenomenon of these parameters with the applied power suggests that self-heating can be the major cause of degradation of polysilicon TFTs.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.4
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• pp.356-363
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• 2005

The purpose of this paper is to investigate the optimal condition of the Syngas production by reforming of fuel using plasmatron. Plasma was generated by air and arc discharge. The effects of applied steam, $CO_2$ or Ni-catalyst on fuel conversion, as well as hydrogen yield and $H_2$/CO ratio were studied. When the variations of $O_2$/fuel ratio, $H_2O$/fuel flow ratio and $CO_2$/fuel flow ratio were $0.94{\sim}1.48$, $4.3{\sim}10$ and $0.8{\sim}3.05$, respectively. Under the condition mentioned above, result of $H_2O$/fuel flow ratio was maximum $H_2$ concentration, or $28.2{\sim}31.6%$, and result of $H_2O$/fuel flow ratio with catalyst was minimum CO concentration or $6.6{\sim}7.1%$. and $H_2$/CO ratio were $3.89{\sim}4.86$.

• Journal of Nutrition and Health
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• v.34 no.6
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• pp.619-625
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• 2001

Diabetes mellitus was induced in male Sprague-Dawley rats weighing 200-245g by injection of streptozotocin(STZ) into the tail vein at a dose of 45mg/kg and were divided into seven groups ; normal, diabetic control, and five experimental groups(fractions of hexane, chloroform(CHCl$_3$), ethylacetate(EtOAc), butanol(BuOH) and water($H_2O$)). The rats of all groups were fed on AIN-93 diet and the five experimental groups were orally administered each fraction for 14 days. The body weight and diet intake were monitored daily. The plasma levels of glucose, insulin, cholesterol, triglyceride, HDL-cholesterol, free fatty acid and aspartate and alanine aminotransferase activities were analyzed. Diabetic rats showed the lower weight gain compared to the normal rats. The plasma glucose levels of the CHCl$_3$, and $H_2O$ fraction groups were significantly lower than the other experimental groups. The plasma insulin level of the CHCl$_3$ fraction group was much higher than that of diabetic control group. The plasma cholesterol levels were increased in all the experimental groups. The groups of hexane, BuOH and H2() fractions showed the lower plasma triglyceride levels compared to diabetic control group. The plasma free fatty acid levels were not significantly different in all groups. HDL-cholesterol levels were definitely higher in hexane, CHCl$_3$ and EtOAc fraction groups than that of diabetic control group. In conclusion, administration of CHCl$_3$ and $H_2O$ fractions of methanol extract of Alisma canaliculatum exhibited hypoglycemic effects in STZ induced diabetic rats, showing the possibility of therapeutic use of Alisma canaliculatum to the diabetes mellitus.

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.813-818
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• 1995

A diamond-like carbon (DLC) film was produced on a TiO2 substrate using a plasma enhance chemical vapor deposition (PECVD) method. The CH4-H2 plasma was produced by applying 400 V DC. The DLC film with the best crystalline structure was obtained when the concentration of CH4 in H2 was 0.75 percent by volume and total pressure was 40 torr. The presence of the diamond structure was confirmed by Raman spectroscopy, X-ray diffraction, and scanning electron microscopy methods. It was found that the diluting gas H2 played an important role in producing a DLC film using a PECVD method.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.1
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• pp.93-99
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• 2012

The investigation of clean and environment-friendly coal utilization technology is actively progressed due to high oil price and serious climate change caused by greenhouse gas emissions. In this study, the plasma gasification was performed using a 6kW microwave plasma unit under various reaction conditions: the particle sizes of coal ($45{\mu}m-150{\mu}m$), $O_2$/fuel ratio (0 - 1.3), and steam/fuel ratio (0 - 1.5). The $H_2$ composition decreases with decreasing coal particle size. With increasing $O_2$/fuel ratio, the $H_2$ composition in the syngas decreased while the $CO_2$ composition increased. As the steam/fuel ratio increased from 0 to 1.5, the $H_2$ composition in the syngas increased while the $CO_2$ composition decreased. From the results, it was proven that the variation of syngas composition greatly affected by $O_2$/fuel ratio than steam/fuel ratio. The $H_2$ composition in the syngas, carbon conversion, and cold gas efficiency increased with increasing plasma power.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.10
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• pp.710-715
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• 1999

The purpose of this work is to develop a high-efficiency air cleaning system for air pollutants such as particulate and gaseous state in indoor environments. In order to enhance a removal efficiency of gaseous state pollutants, we suggested that pulsed discharge plasma be combined with $TiO_2$ photocatalyst (photocatalytic plasma air cleaning unit). We investigated experimentally the basic characteristics of photocatalytic plasma air cleaning unit and measured air pollutants removal efficiency. The wavelength of light radiated from pulsed discharge plasma under the atmospheric condition was 310~380nm. Its energy is enough to excite the $TiO_2$ photocatalyst and it makes a photochemical reaction in the surface of $TiO_2$ photocatalyst. The removal quantity of trimethylamine$((CH_3)_3N)\; was\; 130mg/m^34 which is twice quantity of pulsed discharge plasma without $TiO_2$ phtocatalyst unit. From the result of gas analysis using FT-IR, nitric oxide was not detected and trimethylamine was decomposed to $H_2O\; and \;CO_2$. And trimethylamine removal efficiency was 95%. These experimental results indicate that photocatalytic plasma air cleaning unit is a potential method in removing the pollutants.