• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.288-288
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• 2013

We report the catalytic activity of Au/$TiO_2$ and Pt/$TiO_2$ nanocatalysts under CO oxidation fabricated by arc plasma deposition (APD), which is a facile dry process with no organic materials involved. Using APD, the catalyst nanoparticles were well dispersed on $TiO_2$ powder with an average particle size (2~4 nm) well below that of nanoparticles prepared by the sol-gel method (10 nm). We found that the average particle size of the dispersed gold nanoparticles can be controlled by changing the plasma discharge voltage of APD. Accordingly, the amount of loaded gold on the $TiO_2$ powder increased with increasing discharge voltage, but the specific surface area of the Au/$TiO_2$ samples decreased. As for catalytic reactivity, Au/$TiO_2$ showed a higher catalytic activity than Pt/$TiO_2$ in CO oxidation. The catalytic activity of the Au/$TiO_2$ samples showed size dependence where higher catalytic activity occurred on smaller gold nanoparticles. The study suggests that APD is a simple way to fabricate catalytically active nanocatalysts.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.540-543
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• 2011

This work is devoted to an experimental investigation on conceptual design of dual consecutive stage micro plasma thruster (${\mu}PT$). Optimization study on the thruster configuration has been performed for various electrode gap distances from 1 mm to 2 mm and the hole diameter from 0.3 mm to 2 mm depending on desired operating conditions and corresponding nozzle design requirement. The operation of ${\mu}PT$ at low pressure from $10^{-1}$ Torr to $10^{-4}$ Torr and at various argon flow rates ranging from 5 sccm to 300 sccm has been studied to understand the physic of plasma and the gas dynamics in details. The specific impulse can reach up to 3000-4000 seconds at low power consumptions from 1 to 5 W. Image of exhaust plume from ${\mu}PT$ will be provided and electrical characteristics is also mentioned in this paper.

• Journal of Environmental Science International
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• v.26 no.3
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• pp.325-334
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• 2017

To understand the changes in physical parameters and phytoplankton size structure caused by tides, a fixed station in the Youngsan River estuary was monitored at 2-h intervals, on April 28, 2012 and August 12, 2012. No clear relationship was observed between the temperature and salinity changes and tidal levels in April. However, in August, temperature decreased during the ebb tide and increased during the flood tide, while salinity showed the opposite trend. In addition, there was no specific change in the phytoplankton biomass corresponding to tidal levels in April. In August, the total chlorophyll a and the biomass of net phytoplankton (>$20{\mu}m$) increased almost 20 times during the ebb tide and decreased during the flood tide. The biomass of nanophytoplankton (<$20{\mu}m$) showed a similar variation in response to tidal level changes. In April, the relationship between percent contributions of phytoplankton size structure and tidal levels was not clear. In August, the net phytoplankton was dominant in the early stage and nanophytoplankton was dominant in the later stage, while contribution of nanophytoplankton and net phytoplankton increased at high tide and low tide, respectively. Therefore, in April, other factors such as freshwater discharge were more important than the tide, whereas in August, when no freshwater discharge was recorded, the changes in semidiurnal tides influenced the physical parameters and phytoplankton dynamics. These results could contribute to the understanding of phytoplankton dynamics in the Youngsan River estuary.

• Ocean and Polar Research
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• v.31 no.2
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• pp.177-187
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• 2009

This study examined the multi-scale variabilities of sea surface temperature (SST) and salinity in the Japan/East Sea (JES) based on statistical analyses of observational data, with a focus on the northwestern part of the sea. The regionality of JES SST variability was estimated for different frequency ranges on semimonthly (11-17 days), monthly to seasonal (30-90 days), quasi-semiannual (157-220 days), and quasi-biennial (1.5-3 years) time scales using cluster analyses of daily gridded SST data for 1996 to 2007 from the Japan Meteorological Agency (JMA). Several significant peaks and regional cores were found in each frequency range of the SST anomaly (SSTA) oscillations. Quasi-semiannual SSTA oscillations with high amplitude were found in the south-southwestern part of the Japan Basin ($41-43^{\circ}N$) and were amplified in the area adjacent to Peter the Great Bay. Oscillations with periods of 79 and 55 days also prevailed over the southwest Japan Basin between the Yamato Rise and the continental slope. A similar method was applied to classify SST and the annual cycle of surface salinity using Generalized Digital Environmental Model (GDEM) gridded data. The Tatarskii Strait and adjacent area showed the most specific annual cycles and variability in salinity on interannual to interdecadal time scales. The most significant inverse relationship between surface salinity in the Tatarskii Strait and southern JES areas was found on the interdecadal time scale. Linkages of sea water salinity in the Tatarskii Strait with Amur River discharge and wind velocity over Amurskii Liman were also revealed.

• Journal of the Korean Society of Costume
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• v.55 no.5 s.95
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• pp.101-107
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• 2005

In this article, mordant absorption rate by the Change of temperature and fabric, discharge level by water washing, mordant density and method in mordant dye are going to be handled. Besides, how treatment method will have an effect on absorption rate and color, is also going to be covered. An atom extinction photometer was used to measure the amount of mordant absorbed in fabric at each temperature and mordant type. It turned out that absorption rate differs according to the type of mordant and sample or temperature. Also it turned out that the mordant input amount has little influence on absorption rate, that is to say, if though you use more mordants, just tiny amount of mordant is going to be absorbed in cloth. It is true that the higher temperature goes up, the better mordant absorption gets. It is found that the type of mordant and sample, treatment period affects the discharge rate. Normally $15{\~}98\%$ mordant comes off the fabric by water washing, to be specific, $17{\~}47\%$ Iron by water washing and it has better performance on cotton and nylon than silk, $1\%{\~}52\%$ Aluminum by water washing and better absorption on silk, $36{\~}89\%$ Chrome by water washing and better absorption on silk, $50{\~}89\%$ copper by water washing and better absorption on silk, poor on cotton. The examination of the K/S values and colors between before and after soaping has been conducted under the circumstance that the test fabrics had been treated at $80^{\circ}C$ for 30 minutes with $0.2\%$ soaping solution. In case of pre-mordanted fabrics, the K/S value nosedived after soaping, meanwhile densely mordanted fabric's K/S value soared but after soaping, it dropped sharply. It turned out that soaping treatment deteriorates absorption much more than water washing. It's considered that $0.1 \%$ (W/V) of mordant density is appropriate.

• The Journal of Korean Medicine
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• v.22 no.3
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• pp.42-50
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• 2001

Objectives : Dysphagia is common and severe problems of acute stroke determining the prognosis of stroke only second to mental change, and results in secondary fatal complications such as aspiration pneumonia, malnutrition, dehydration, etc. Therefore, we were to investigate the clinical characteristics of dysphagia accompanied by acute ischemic stroke. Methods : We selected subjects through clinical notes retrospectively, whose main problems included dysphagia resulted from acute stroke within 72 hours from onset who were admitted to the Internal Medicine Department of Wonkwang Oriental Medicine Hospital from Jan. 2000 to Apr. 2001. We assessed the severity of dysphagia from admission to discharge using a staging method : stage 0 is normal without dysphagia, stage 1 is nearly normal except for intermittent dysphagia, stage 2 is compensated abnormal swallowing requiring adjusted diets or delayed feeding time, stage 3 is uncompensated abnormal swallowing resulted in weight loss down to 10% of initial and daily aspiration, coughing, and vomiting, stage 4 is uncompensated abnormal swallowing resulting in weight loss beyond 10% and recommended for non-oral feeding, and stage 5 is 100% non-oral feeding by L-tube, or gastrostomy or NPO state. Results : Dysphagia was improved statistically significantly from the mean stage of $3.6{\pm}0.29$ on admission to $1.88{\pm}0.32$ on discharge (P<0.05). On average $7.1{\pm}1.48$ days were required for improving more than one stage level. As patients were older and the stage of dysphagia was worse on admission, severity of dysphagia was more difficult to improve (correlation coefficiency was 0.55 and 0.77 respectively, P<0.05). Aspiration pneumonia was complicated in 13 patients of the total 25 at mean dysphagia stage of $3.36{\pm}0.37$. However, any specific values such as lesion size, lesion site, sex, age, past history and NIH Stroke Scale on admission did not affect it (P>0.05). Conclusion : Clinical course of dysphagia was determined about I week from the onset. Aspiration pneumonia was mainly complicated during oral feeding periods. If there were no improvement of dysphagia over 2-3 weeks, then non-oral feeding such as Levin tube or gastrostomy must be considered.

• Journal of Korea Water Resources Association
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• v.41 no.6
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• pp.605-617
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• 2008

This study developed a flood index which evaluates runoff characteristics. Runoff characteristics expressed in a hydrograph were reflected in the flood index in the form of characteristic factors such as a rising curve gradient, a peak discharge, a flood response time, and a flood discharge volume prior to peak. This study applied the standardization method to estimate the relative severity of the characteristic factors by transforming the distribution of characteristic factors into the standard normal distribution. The flood index developed in this study is a comprehensive flood index (CFI) which makes up for the weak points of a flash flood index (FFI) in determining relative severities. The CFI was applied to Han River basin and Selma River basin, and was compared with the FFI based on the correlation analysis and the regression analysis. The CFI could comprehensively evaluate flood runoff characteristics because the CFI is not dominated by a specific characteristic factor, and the CFI could explain more efficiently the relationship between rainfall and runoff than the FFI.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.218.1-218.1
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• 2014

In order to measure the absolute plasma density, various probes are proposed and investigated and microwave probes are widely used for its advantages (Insensitivity to thin non-conducting material deposited by processing plasmas, High reliability, Simple process for determination of plasma density, no complicate assumptions and so forth). There are representative microwave probes such as the cutoff probe, the hairpin probe, the impedance probe, the absorption probe and the plasma transmission probe. These probes utilize the microwave interactions with the plasma-sheath and inserted structure (probe), but frequency range used by each probe and specific mechanisms for determining the plasma density for each probe are different. In the recent studies, behaviors of each microwave probe with respect to the plasma parameters of the plasma density, the pressure (the collision frequency), and the sheath width is abundant and reasonably investigated, whereas relative diagnostic characteristics of the probes by a comparative study is insufficient in spite of importance for comprehensive applications of the probes. However, experimental comparative study suffers from spatially different plasma characteristics in the same discharge chamber, a low-reproducibility of ignited plasma for an uncertainty in external discharge parameters (the power, the pressure, the flow rate and so forth), impossibility of independently control of the density, the pressure, and the sheath width as well as expensive and complicate experimental setup. In this paper, various microwave probes are simulated by finite-different time-domain simulation and the error between the input plasma density in FDTD simulations and the measured that by the unique microwave spectrums of each probe is obtained under possible conditions of plasma density, pressure, and sheath width for general low-temperature plasmas. This result shows that the each probe has an optimum applicable plasma condition and reliability of plasma density measurement using the microwave probes can be improved by the complementary use of each probe.

• Ocean and Polar Research
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• v.30 no.1
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• pp.89-107
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• 2008

Marine environment is subject serious destruction because of frequent accidents during exploration of marine resources and overseas transport. Also, as many industrial enterprises discharge high volume of wastes and contamination, marine pollution has become a serious threat to people (especially in China). China is quickly becoming a world economic leader of the 21st century. Rapid industrialization and social changes have raised the standard of living of millions of the Chinese, mainly in the areas of East and South East coast. The process of industrialization, however, is often followed by deterioration of the marine environment and rarely turned around until a country has increased its standard of living. Solving these array of problems will take decades and currently the government is addressing minor specific issues only. Fortunately, the Chinese government has enacted a number of marine pollution control laws. On 25 December 1999, the 13th Session of the Ninth Standing Commettee of the National People's Congress passed the amended the Marine Environment Protection Law of the People's Republic of China. This Law establishes rights and responsibilities of the relevant departments concerning marine environment management and provides for two new chapters on "Marine Environment Supervision" and "Marine Ecological Protection", along with "Supervision of Pollution Prevention for Marine Construction Projects", "Marine Ecological Protection" and "Marine Environment Pollution Prevention for Marine Construction Projects". Also, the Law was amended with provisions for integrated pollution discharge control system and oil spillage emergency response plan and enhanced legal responsibilities. Chinese government recognizes that international and national experience can be useful for China to prevent further ecological degradation of the marine environment.

• Journal of the Korean Electrochemical Society
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• v.5 no.2
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• pp.74-78
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• 2002

Zinc Air battery obtain their energy density advantage over the other batteries by utilizing ambient oxygen as the cathode materials, and reusing cathode as recycled form. And specific capacity of zinc powder is as high as 820 mAh/g. However, if the pore size in cathode is small then the flow rate of air decreased, and as a result of that discharge voltage of batteries becomes low. We focused on resistance and porosity of cathode. So we studied the effects of conducting agents to zinc air batteries performance, capacity, power density, average discharge voltage, resistance. And we also measured porosity of cathode by the ASTM. So we have got optimum contents of conducting agent.