• 한국진공학회지
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• 제5권3호
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• pp.213-217
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• 1996

서냉법과 용액성장법으로 HgS 및 HgS : Co 결정과 박막을 성장시켜서 결정구조를 조사하고 , 광흡수를 측정했다. 이들 결정 및 박막은 육방정계 구조로써 HgS 및 HgS : Co 결정의 격자상수는 각각 $aa_0=4.155\AA$, $c_0=9.505{\AA}$과 ao=4.148$\AA$, co=9.487$\AA$ 이었다. 또한 HgS 및 HgS박막에 대한 격자상수는 각각 $a_0=4.148{\AA}$, $c_0=9.462{\AA}$와 $a_0=4.135{\AA}$, $c_0=9.442{\AA}$으로 주어졌다. 293K에서 측정된 광학적 에너지 간격은 HgS 및 HgS : Co 결정이 2.040eV, 1.900eV 이고, HgS 및 Hgs : Co 박막은 2.440, 1.940eV 로 각각 주어졌다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.122-122
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• 2011

HgCdTe는 고성능 적외선 센서 재료로 널리 사용되고 있다. 현재 상용화된 HgCdTe 소재는 통상적으로 액상 에피 성장법으로 제조 되고 있다. 액상 에피 성장법에 의해 제조된 HgCdTe는 갓 성장 상태에서 많은 양의 Hg-공공(vacancy)을 함유하게 되며 적외선 소자의 응용을 위해서는 이러한 Hg-공공을 채우기 위한 Hg-분위기 열처리 공정을 거치게 된다. 열처리 혹은 성장 공정 시 HgCdTe 소재 내에 발생하는 마이크로 혹은 나노스케일의 조성의 변화는 응력의 집중을 가져오며 이는 전자, 혹은 정공의 응집을 가져와 소자 동작의 불균일성을 야기한다. 본 연구에서는 액상 에피 성장법으로 성장 된 HgCdTe 박막내에 존재하는 응력의 분포와 Hg-공공을 채우기 위한 열처리 과정에서 생성 또는 소멸되는 응력의 변화를 Geometric phase strain 분석법으로 관찰하였다. 분석결과, 응력의 집중된 부분은 주로 성장 시 석출된 Te 및 Hg-공공으로 부터 기인함을 확인하였다. Hg-분위기 열처리를 통하여 석출된 Te 제거 및 Hg-공공의 감소를 확인하였고 이에 따른 응력의 집중 부분도 해소됨을 알 수 있었다.

• Advances in environmental research
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• 제1권1호
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• pp.15-35
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• 2012

Mercury (Hg) is a global environmental pollutant that has been the cause of many public concerns. One particular concern about Hg in aquatic systems is its trophic transfer and biomagnification in food chains. For example, the Hg concentration increases with the increase of food chain level. Fish at the top of food chain can accumulate high concentrations of Hg (especially the toxic form, methylmercury, MeHg), which is then transferred to humans through seafood consumption. Various biological and physiochemical conditions can significantly affect the bioaccumulation of Hg-including both its inorganic (Hg(II)) and organic (MeHg) forms-in fish. There have been numerous measurements of Hg concentrations in marine and freshwater fish worldwide. Many of these studies have attempted to identify the processes leading to variations of Hg concentrations in fish species from different habitats. The development of a biokinetic model over the past decade has helped improve our understanding of the mechanisms underlying the bioaccumulation processes of Hg in aquatic animals. In this review, I will discuss how the biokinetic modeling approach can be used to reveal the interesting biodynamics of Hg in fish, such as the trophic transfer and exposure route of Hg(II) and MeHg, as well as growth enrichment (the increases in Hg concentration with fish size) and biomass dilution (the decreases in Hg concentration with increasing phytoplankton biomass). I will also discuss the relevance of studying the subcellular fates of Hg to predict the Hg bioaccessibility and detoxification in fish. Future challenges will be to understand the inter- and intra-species differences in Hg accumulation and the management/mitigation of Hg pollution in both marine and freshwater fish based on our knowledge of Hg biodynamics.

• 한국환경보건학회지
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• 제33권3호
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• pp.180-183
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• 2007

Over the last century the mercury (Hg) concentration in the environment has been increased by human activities with inputs from sources such as atmospheric deposition, urban runoff, and industrial effluents. Mercury can be transformed to methylmercury (MeHg) in anaerobic conditions by sulfate reducing bacteria (SRB) and sediments are the principal location for MeHg production in aquatic environments. Interest in bioaccumulation of Hg and MeHg into lower trophic levels of benthic and pelagic organisms stems from public health concerns as these organisms provide essential links for higher trophic levels of food chains such as fish and larger invertebrates. Fish consumption is the major exposure route of MeHg to humans. Recently, it was reported that blood samples in Korea showed much higher Hg levels (5-8 times) than those in USA and Germany. Although this brings much attention to Hg research in Korea, there are very few studies on Hg biogeochemical cycling and bioaccumulation in aquatic environments. Given the importance of Hg methylation and MeHg transfer through food chains in aquatic environments, it is imperative that studies should be done in much detail looking at the fate, transport, and bioaccumulation of Hg and MeHg in the environment. Moreover, there should be long-term monitoring plans in Korea to evaluate the environmental and health effects of Hg and MeHg.

• Journal of Korean Society for Atmospheric Environment
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• 제24권E1호
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• pp.1-11
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• 2008

Mercury (Hg), which is mainly emitted from coal-fired power plants, remains one of the most toxic compounds to both humans and ecosystems. Hg pollution is not a local or regional issue, but a global issue. Hg compounds emitted from anthropogenic sources such as coal-fired power plants, incinerators, and boilers, can be transported over long distances. Since the last decade, many European countries, Canada, and especially the United States, have focused on technology to control Hg emissions. Korea has also recently showed an interest in managing Hg pollution from various combustion sources. Previous studies indicate that coal-fired power plants are one of the major sources of Hg in Korea. However, lack of Hg emission data and feasible emission controls have been major obstacles in Hg study. In order to achieve effective Hg control, understanding the characteristics of current Hg sampling methods and control technologies is essential. There is no one proven technology that fits all Hg emission sources, because Hg emission and control efficiency depend on fuel type, configuration of air pollution control devices, flue gas composition, among others. Therefore, a broad knowledge of Hg sampling and control technologies is necessary to select the most suitable method for each Hg-emitting source. In this paper, various Hg sampling methods, including wet chemistry, dry sorbents trap, field, and laboratory demonstrated control technologies, and international regulations, are introduced, with a focus on coal-fired power plants.

• Bulletin of the Korean Chemical Society
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• 제28권3호
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• pp.439-442
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• 2007

A solid state Hg(Au)/HgO reference electrode was prepared utilizing gold amalgam solid particles. Solid fine powder of the gold amalgam was prepared by chemical reduction of Au(III) with NaBH4 followed by reduction of Hg(II) in the presence of gold fine particles. The solid content in the suspension of the gold amalgam particles and fine mercury oxide particles in DMF containing PVC was precipitated by the addition of a large amount of water to give solid Hg(Au)/HgO/PVC mixture. After drying, the mixture was pressure-molded to a physically stable Hg(Au)/HgO composite reference electrode material. The electrochemical characteristics of the electrode as a reference electrode were very similar to an ordinary Hg/HgO reference electrode. The electrode material can be molded and fabricated in any desired shape and size. The surface can be renewed by a simple polishing process whenever contaminated or deactivated. The applicability of the electrode in the electrochemical detection of carbohydrates after anion exchange separation was evaluated.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.73-83
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• 2005

Higher methylmercury (MeHg) accumulation and susceptibility to toxicity in the fetus than in the mother at parturition is well known. However, the difference in MeHg exposure to fetus and offspring throughout gestation and suckling is not well established. In the human, the effects of MeHg exposure on pregnant and breast-feeding women remain an important issue for elucidation, especially those of continuous uptake in high-fish-consumption populations. The purpose of this paper was to evaluate the difference in MeHg exposure to fetus and offspring throughout gestation and lactation using our recent animal and human studies data. In the animal study, adult female rats were given a diet containing 5 ${\mu}$g/g Hg (as MeHg) for 8 weeks. Then they were mated and subsequently given the same diet throughout gestation and suckling. On embryonic days 18, 20, 22 and at parturition, the concentrations of Hg in the brains of fetus were approximately 1.5-2.0 times higher than those in the mothers. However, during the suckling period Hg concentrations in the brain rapidly declined to about 1/10 of that during late pregnancy. Hg concentrations in blood also decreased rapidly after birth. In human study, Hg concentrations in red blood cells (RBCs-Hg) in 16 pairs of maternal and umbilical cord blood samples were compared at birth and 3 months of age after parturition. RBCs-Hg concentration in the umbilical cords was about 1.6 times higher than those in the mothers at parturition. However, all the infants showed declines in Hg concentrations throughout the breast-feeding period. The Hg concentration in RBCs-Hg at 3 months of age was about half that at birth. Both the animal and human studies indicated that MeHg exposure to the fetus might be especially high but it dramatically decreases during the suckling period. Therefore, close attention should be paid to the gestation rather than the breast-feeding period to avoid the risk of MeHg to human infants.

• 센서학회지
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• 제19권5호
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• pp.398-402
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• 2010

The liquid phase epitaxy(LPE) method was widely used to growth of mercury cadmium telluride(MCT) thin films. However, this method lead to Hg-vacancies in MCT thin film, because Hg has high vapor pressure at this temperature range. This is a well known defect in HgCdTe grown by LPE method. In this study, we report the development of techniques for improving the crystalline quality and controlling the composite uniformity of HgCdTe thin films using high- pressure Hg-ambient annealing method. As a result, we achieved the improvement of the composite uniformity of HgCdTe thin films. It was observed by the high angle annular dark field scanning TEM(HAADF-STEM) analysis. Moreover, new HgTe phase and a shrinking of lattice fringe were observed.

• 한국안광학회지
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• 제11권2호
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• pp.91-97
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• 2006

한국인 청년 남, 여 1,027명(남자=475, 여자=552)을 대상으로 안압의 상대 빈도 분포를 조사하였다. 상대적 빈도의 최고값은 남, 여에서 각각 14.5mmHg와 17.5mmHg이었으며, 전체 안압 빈도 분포범위는 남, 여에서 각각 7~23mmHg와 7~22mmHg이었다. 그리고 누적 빈도 중앙값 (누적빈도=0.5)은 남, 여에서 각각 13.0~16.5mmHg와 16.5~18.5mmHg로 여자가 남자 보다 더 높았다. 평균 안압은 남, 여에서 각각 15.2mmHg와 15.8mmHg이었고 조사 대상의 98%가 정상 안압의 범위에 속했다. 안압은 일차 변동을 나타냈는데 아침에서 저녁으로 가면서 감소하는 추세를 보였다. 안압 변동의 추세선을 보면 운동에 의해 안압이 감소되었으며 넥타이를 맨 경우와 누워있는 자세를 유지하는 동안 안압은 추세적으로 증가되었다.

• The Korean Journal of Ecology
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• 제22권2호
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• pp.89-94
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• 1999

Thirty-day-old seedlings of tomato (Lycopersicon esculentum) were treated with different concentrations of HgCl$_2$(0. 10 and 50 $\mu$M) for up to 20 days. and the detailed distribution of Hg absorbed and its toxicity in different plant parts (roots, stems and leaves) were investigated. The accumulation of Hg in plants increased with external Hg concentrations. and Hg is strongly retained by roots. Further. Hg content in leaves was various. showing more accumulation in older leaves. Seedlings exposed to toxic levels of Hg showed not only the reduction of dry weight and length of both shoot and root. and chlorophyll levels in leaves but also the enhancement of malondialdehyde (a lipid peroxidation product) formation in all plant parts investigated. These results suggest that physiological impairment of a plant exposed to Hg may be achieved by internal distribution of Hg absorbed and Hg-induced oxidative stress in different plant parts.