• 한국재료학회지
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• 제30권12호
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• pp.687-692
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• 2020

A zinc-air battery consists of a zinc anode, an air cathode, an electrolyte, and a separator. The active material of the positive electrode is oxygen contained in the ambient air. Therefore, zinc-air batteries have an open cell configuration. The external condition is one of the main factors for zinc-air batteries. One of the most important external conditions is temperature. To confirm the effect of temperature on the electrochemical properties of zinc-air batteries, we perform various analyses under different temperatures. Under 60 ℃ condition, the zinc-air cell shows an 84.98 % self-discharge rate. In addition, high corrosion rate and electrolyte evaporation rate are achieved at 60 ℃. Among the cells stored at various temperature conditions, the cell stored at 50 ℃ delivers the highest discharge capacity; it also shows the highest self-discharge rate (65.33 %). On the other hand, the cell stored at 30 ℃ shows only 2.28 % self-discharge rate.

• 한국대기환경학회지
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• 제2권1호
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• pp.11-21
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• 1986

The study was performed to investigate the effects of gaseous imission of sulfur dioxide and hydrogen fluoride on the growth of rice plant under stressed field conditions. The plants were cultivated in normal paddy fields where are 88 industrial plants operating with 285 smoke stacks emitting pollutants. There has been a number of reported studies (1, 3, 11, 19, 20) which deal with rice plant damages by air pollution under a simulated exposure experimental condition. Furthermore, these experiments were conducted to examine effects of a single pollutant on the plant. Furthermore, these experiments were conducted to examine effects of a single pollutant on the plant. In korea, however, there is no study reported in literature with respect to the in-situ dose-response relationship between rice pant reduction in yields and air pollution. This study is specifically dealt with multiple effects of sulfur dioxde and hydrogen fluoride on various plant growth indicators such as leaf damage, culm height, weight of grain, panicles per hill, spikelets per panicle and percent fertility.It appears that there is a good correlation between ambient concentrations of sulfur oxides and sulfur contents found in leaves with an average correlation coefficient of 0.868 within a 1% significance level. It is interesting to note that a better multiple correlation was found between percent leaf damage and sulfur and fluoride contentd found in leaf with a significance of 1% level. The yearly correlation coefficient ranges from 0.963 to 0.987 with an average being 0.971. It is, therefore, believed that a percent leaf damage may serve as a single indicator of pollutional damages to rice plant cultivating in fields. Regarding other factors to the diminution of rice plant growth in polluted atmosphere, it appears that a significant correlation to culm length and dry weight of grain with a 1% significance level whereas T/R ratio has a good correlation with lead damage within 5% significance level. An evaluation of data observed has demonstrated that both panicles per hill and percent fertility are significantly affected by air pollutants. As expected, hydrogen fluoride has more effects than sulfur oxide. It is, however, interesting to note that spikelets per panicles has slightly been affected while no indication of effects on 1000-grain-weight has been observed. This may lead to a conclusion that a reduction in yield of rice under polluted field conditions may have more been caused by the diminution of panicles per hill and percent fertility rather than by the diminution of spikelets per panicle and grain weight.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1998년도 제14회 학술발표회 논문개요집
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• pp.120-120
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• 1998

Boron nitride (BN) films have attracted a growing interest for a variety of t technological applications due to their excellent characteristics, namely hardness, c chemical inertness, and dielectrical behavior, etc. There are two crystalline phases 1551; of BN that are analogous to phases of carbon. Hexagonal boron nitride (h-BN) has a a layered s$\sigma$ucture which is spz-bonded structure similar to that of graphite, and is t the stable ordered phase at ambient conditions. Cubic boron nitride (c-BN) has a z zinc blende structure with sp3-bonding like as diamond, 따ld is the metastable phase a at ambient conditions. Among of their prototypes, especially 삼Ie c-BN is an i interesting material because it has almost the same hardness and thermal c conductivity as di없nond. C Conventionally, significant progress has been made in the experimental t techniques for synthesizing BN films using various of the physical vapor deposition 밍ld chemical vapor deposition. But, the major disadvantage of c-BN films is that t they are much more difficult to synthesize than h-BN films due to its narrow s stability phase region, high compression stress, and problem of nitrogen source c control. Recent studies of the metalorganic chemical vapor deposition (MOCVD) of I III - V compound have established that a molecular level understanding of the d deposition process is mandatory in controlling the selectivity parameters. This led t to the concept of using a single source organometallic precursor, having the c constituent elements in stoichiometric ratio, for MOCVD growth of 삼Ie required b binary compound. I In this study, therefore, we have been carried out the growth of h-BN thin f films on silicon substrates using a single source precursors. Polycrystalline h-BN t thin films were deposited on silicon in the temperature range of $\alpha$)() - 900 $^{\circ}$C from t the organometallic precursors of Boron-Triethylamine complex, (CZHs)3N:BRJ, and T Tris(dimethylamino)Borane, [CH3}zNhB, by supersonic molecular jet and remote p plasma assisted MOCVD. Hydrogen was used as carrier gas, and additional nitrogen w was supplied by either aDlIDonia through a nozzle, or nitrogen via a remote plasma. T The as-grown films were characterized by Fourier transform infrared spectroscopy, x x-ray pthotoelectron spectroscopy, Auger electron spectroscopy, x-ray diffraction, t transmission electron diffraction, optical transmission, and atomic force microscopy.roscopy.

• 한국식품과학회지
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• 제31권6호
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• pp.1447-1452
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• 1999

백삼의 생물학적 품질개선이 가능한 phosphine gas와 감마선 처리(5 kGy 이하)가 저장시료의 지방질 관련 성분에 미치는 영향을 비교 검토하였다. 시료의 pH는 gas 처리에 따라 다소 염기성을 나타내었으며, 상온조건$(20^{\circ}C/70%\;RH)$ 및 가혹조건$(40^{\circ}C/90%\;RH)$에 6개월 간 포장 저장 중 전반적으로 다소 감소되었다. 가혹조건에 저장된 시료는 저장초기부터 갈변현상이 심하게 발생되었으나 상온 저장된 시료에서는 거의 갈변되지 않았고 처리구 간에도 차이가 크지 않았다. 시료의 갈변현상의 발현은 저장 4개월 경까지 추출물의 수소공여능과 비례하였다. 시료 지방질 TBA가는 감마선 조사시 다소 증가되었으나 저장기간의 경과로 점차 유사한 값을 보였으며, 카보닐가는 점차 증가되는 경향이었다. 시료의 지방산 조성은 가스나 5 kGy 감마선 처리에 의해 변화되지 않았으며, 저장 6개월 이후에는 불포화지방산조성의 감소와 포화지방산조성의 증가 현상이 부분적으로 확인되었다.

• 한국환경농학회지
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• 제7권2호
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• pp.130-135
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• 1988

울출공업단지주변지역중(蔚出工業團地周邊地域中) 대기오염(大氣汚染)의 영향(影響)을 많이 받고있는 특정지역(特定地域)에 방풍막(放風幕)을 설치(設置)하여 배출원(排出源)에서 방출(放出)되는 대기오염물(大氣汚染物)의 영향(影響)을 줄이고, 피해원인(被害原因)을 구명(究明)하기위해 방풍막(放風幕) 앞뒤의 오염도(汚染度)와 수도(水稻)의 생육상태(生育狀態)를 조사(調査), 검토(檢討)한 결과(結果)는 다음과 같다. 1. 방풍막(放風幕) 후면(後面) 3m지점(地點)의 대기중(大氣中) $SO_2$ 및 HF농도(濃度)와 엽내유황(葉內硫黃) 및 불소함량(弗素含量)은 다른 조사지점(調査地點)보다 낮았으며, 대기중(大氣中) $SO_3$농도(濃度)와 엽내유황함량(葉內硫黃含量), 대기중(大氣中) HF농도(濃度)와 엽내불소함량간(葉內弗素含量間)에 정(正)의 상관(相關)을 보여주었다. 그리고 막후면(幕後面) 3m지점(地點)의 수량(收量)과 수량구성요소(收量構成要素)는 다른 조사지점(調査地點)보다 현저히 높은 수치(數値)를 보였다. 2. 대기중(大氣中) $SO_2$ 및 HF농도(濃度)보다는 엽내유황(葉內硫黃) 및 불소함량(弗素含量)이 수도(水稻)의 수량(收量) 및 수량구성요소(收量構成要素)와의 높은 상관(相關)이 인정(認定)되었다.

• Toxicological Research
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• 제18권1호
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• pp.13-22
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• 2002

In Korea, 2,320 tonnes of acetanilide were mostly wed as intermediates for synthesis in phar-maceuticals or additives in synthesizing hydrogen peroxide, varnishes, polymers and rubber. Only small amount of 120 kg were wed as a stabilizer for hydrogen peroxide solution for hair colouring agents in 1998. Readily available environmental or human exposure data do not exist in Korea at the present time. However, potential human exposures from drinking water, food, ambient water and in work places are expected to be negligible because this chemical is produced in the closed system in only one company in Korea and the processing factory is equipped with local ventilation and air filtering system. Acetanilide could be distributed mainly to water based on EQC model. This substance is readily biodegradable and its bioaccumulation is low. Acute toxicity of acetanilide is low since the L $D_{50}$ of oral exposure in rats is 1,959 mg/kg bw. The chemical is not irritating to skin, but slightly irritating to the eyes of rabbits. horn repeated dose toxicity, the adverse effects in rats were red pulp hyperplasia of spleen, bone marrow hyperplasia of femur and decreased hemoglobin, hematocrit and mean corpuscular hemoglobin concentration. The LOAEL for repeated dose toxicity in rats was 22 mg/kg/day for both sexes. Acetanilide is not considered to be genotoxic. In a reproductive/developmental toxicity study, no treatment-related changes in precoital time and rate of copulation, impregnation, pregnancy were shown in all treated groups. The NOAELs for reproduction and developmental toxicity (off-spring toxicity) are considered to be 200 mg/kg bw/day and 67 mg/kg bw/day, respectively. Ecotoxicity data has been generated in a limited number of aquatic species of algae (72 hr- $E_{b}$ $C_{50}$; 13.5 mg/l), daphnid (48hr-E $C_{50}$ > 100 mg/l) and fish (Oryzias latipes, 96hr-L $C_{50}$; 100 mg/l). Form the acute toxicity values, the predicted no effect concentration (PNEC) of 0.135 mg/1 was derived win an assessment factor of 100. On the basis of these data, acetanilide was suggested as currently of low priority for further post-SIDS work in OECD.in OECD.D.

• 분석과학
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• 제18권1호
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• pp.66-73
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• 2005

본 연구에서는 주요 환원황 화합물에 해당하는 4가지 황성분, $H_2S$, $CH_3SH$, DMS, DMDS을 이용하여, 이들의 주요 검출방법에 해당하는 GC/PFPD 방식의 검출특성을 대부분의 환경시료의 분석에 활용할 수 있는 두 가지 기준에서 비교 분석하였다. 우선 수 십 ppb 단위의 고농도 시료들에 대한 분석특성을 이해하기 위해, GC/PFPD에 루프주입장치를 결합한 고농도 모드 시스템을 구성하고, 이에 대한 평가를 시도하였다. 그리고 이에 대비하여, 열탈착 시스템을 연계한 저농도 모드 시스템을 이용하여, 환경대기와 같이 극단적으로 낮은 농도 (ppt 수준)로 존재하는 시료들의 분석기법을 평가하였다. 양 분석방식의 비교에 의하면, 개별 황성분들의 검출특성은 대단히 규칙적인 특성을 유지하는 것으로 나타났다. 고농도모드를 이용한 비교결과에 의하면, 황화수소의 경우 가장 약한 감도를 보인 반면, 황원소를 두개 함유한 DMDS는 가장 민감한 감도를 보였다. 고농도 모드에 대비하여 저농도 모드의 감도를 비교할 경우, 감도가 수십 배 수준으로 감소하는 것으로 나타났다. 양 방식의 뚜렷한 감도차이에도 불구하고, 선택한 모드에 상관없이 황성분들의 상대적인 검량특성은 비교적 규칙적인 경향성이 유지되는 것으로 나타났다. 이들 성분에 대한 정확한 검량을 위해서는 다양한 관점에서 검출특성을 정의하기 위한 노력이 수반되어야 할 것으로 사료된다.

• 한국토양비료학회지
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• 제40권1호
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• pp.31-35
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• 2007

농작물 안전생산 및 대기환경 개선을 위한 기초 자료로 활용하기 위하여 유해가스에 의한 농작물 피해원인을 구명하였다. 작물 피해현지에서 유해가스에 의한 피해증상을 조사하였으며, 작물체중 유해성분 함량을 분석하였다. 또한, 2004년 경북지역 농공단지에서 발생한 작물피해 사례에 대한 피해원인 구명을 위하여 조사지역의 피해발생 당시 기상자료 및 오염원에서의 배출가스 농도를 적용한 오염물질 확산을 제시하였다. 주요 작물의 암모니아가스 피해증상은 잎 끝으로부터 백색으로 고사하며, 저농도의 경우에는 적갈색 반점이 나타나는 특징을 보였고 화훼류의 경우에는 꽃보다 잎의 피해가 심하게 나타났다. 불소가스 피해증상은 잎의 선단이나 가장자리 부분에 나타나는 특성이 있다. 또한, 유해가스로 인한 작물피해 현지 사례에서 피해 지역의 아황산가스 등농도(等濃度) 분포를 조사한 결과, 조사지역은 발생원으로부터 발생된 아황산가스 영향을 받고 있으며, 특히 계절별로는 기상요인에 따른 여름철의 피해가 우려되었다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 추계학술대회논문집
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• pp.121-128
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• 2009

During a hypothetical high-pressure accident in a nuclear power plant (NPP), molten corium can be ejected through a breach of a reactor pressure vessel (RPV) and dispersed by a following jet of a high-pressure steam in the RPV. The dispersed corium is fragmented into smaller droplets in a reactor cavity of the NPP by the steam jet and released into other compartments of the NPP by a overpressure in the cavity. The fragments of the corium transfer thermal energy to the ambient air in the containment or interact chemically with steam and generate hydrogen which may be burnt in the containment. The thermal loads from the ejected molten corium on the containment which is called direct containment heating (DCH) can threaten the integrity of the containment. DCH in a NPP containment is related to many physical phenomena such as multi-phase hydrodynamics, thermodynamics and chemical process. In the evaluation of the DCH load, the melt dispersion rates depending on the RPV pressure are the most important parameter. Mostly, DCH was evaluated by using lumped-analysis codes with some correlations obtained from experiments for the dispersion rates. In this study, MC3D code was used to evaluate the dispersion rates in the APR1400 NPP during the high-pressure accidents. MC3D is a two-phase analysis code based on Eulerian four-fields for melt jet, melt droplets, gas and water. The dispersion rates of the corium melt depending on the RPV pressure were obtained from the MC3D analyses and the values specific to the APR1400 cavity geometry were compared to a currently available correlation.

• Journal of Photoscience
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• 제1권1호
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• pp.31-37
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• 1994

Photoirradiation at > 300 nm onto a suspension of platinized TiO$_2$ (TiO$_2$-Pt) particles in an aqueous solution. of N$_{\varepsilon}$-carbamyI-L-lysine (Lys(CONH)$_2$) induced the selective N-cyclization of Lys(CONH$_2$) into almost optically pure L-pipecolinic acid (PCA) under argon atmosphere at ambient temperature. Among various TiO$_2$-Pt catalysts, a P-25 (Degussa) powder platinized via impregnation from chloroplatinic acid followed by hydrogen reduction at 753 K exhibited the highest photocatalytic activity for Lys(CONH$_2$) consumption and L-PCA production. GC-MS analyses of L-PCA obtained photocatalytically from $^{15}$N$\alpha$-Lys(CONH$_2$) revealed the selective formation $^{15}$N-substituted L-PCA. This implies that the mechanism for L-PCA production contains selective cleavage of C$_{\varepsilon}$-N bond and intramolecular alkylation at $\alpha$-amino group. Effect of pH on the rate of this photocatalytic reaction was investigated in detail and compared with the pH-dependent charge distribution in Lys(CONH$_2$) molecule. It is clarified that protonation-deprotonation of $\alpha$-amino group gives marked influence on the rate and selectivity of the photocatalytic reaction. On the basis of these results, it is concluded that the selective production of optically pure L-PCA, especially in an acidic suspension of TiO$_2$-Pt, was attributed to the enhanced protonation of $\alpha$-amino group to prevent undesirable oxidation by photogenerated positive holes and blocking of $\varepsilon$-amino group to yield racemic Schiff base intermediate.