• 한국환경농학회지
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• 제16권2호
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• pp.124-129
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• 1997

중금속오염폐수처리에 미생물 이용 가능성을 검토하기 위하여 중금속에 강한 내성을 지님과 동시에 균체내 중금속 축적능력이 우수한 중금속 내성균을 분리하여 온도, pH, 및 균체 전배양시간 등과 같은 외부 요인에 따른 균체내 중금속 축적변화를 조사한 결과는 다음과 같다. 중금속화하물 종류에 따른 균체내 중금속 축적량은 $-nitrate(NO_3)$ group을 가진 중금속화합물에서 약간 높았으나 화합물 종류에 따라서 큰 차이는 없었다. 균체 전배양시간에 따른 중금속 축적은 24시간 전배양한 균체에서 높게 나타났으나 전반적으로 전배양시간에 따라서 큰 차이는 없었다. 중금속 내성균의 균체내 중금속 축적은 온도, pH등 외부환경요인에 영향을 받았으며, 중금속 내성균의 중금속 최적축적 온도는 전반적으로 $20{\sim}37^{\circ}C$ 범위였고, 중금속 최적축적 pH는 전반적으로 $6{\sim}8$ 범위였다. 중금속을 처리한 용액중 중금속 내성균의 균체량을 증가시킬수록 균체내 축적된 총 중금속양은 증가되었으나 균체 단위 g당 중금속 축적량은 감소되었으며, 균체량의 증가에 비례해서 중금속 축적량이 증가되지는 않았다.

• 한국패류학회지
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• 제29권1호
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• pp.7-13
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• 2013

본 연구는 납에 노출된 바지락, Ruditapes philippinarum 의 생물학적 반응을 알아보고자 하였다. 실험기간은 4주였으며, 실험구는 대조구 1개와 납 노출구 3개 (0.25, 0.50 and 1.00 mg/l) 였다. 실험 결과 납은 바지락의 생존율과 산소 소비율의 저하 및 기관계의 조직학적 변성을 유도하는 것이 확인 되었다. 납 노출구에서 산소소비율은 25-72% 감소하였다. 기관계의 조직학적 분석 결과, 외투막 상피층과 결합조직층의 변성, 아가미 점액세포의 증가와 상피세포의 괴사, 발에서는 상피층의 붕괴, 점액세포의 감소 및 혈림프동의 확장과 결합조직층의 변성을 나타냈다. 소화맹낭의 소화선세관에서는 호염기성세포와 상피세포의 위축 및 농도 의존적으로 lipofuscin의 축적이 확인되었다.

• 약학회지
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• 제46권6호
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• pp.375-380
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• 2002

In this study, newly designed COX-2 inhibitors, synthetic derivatives of benzothiazine-3-carboxamide, were screened in vitro for selectivity of COX-1 and COX-2 inhibition properties. 7-Bromo-1,2-benzoisothiazine derivatives were obtained from 4-bromotoluene over the chlorosulfonation, amination and oxidation. And benzothiazine ring was synthesized through Gabriel-Colmann rearrangement reaction. To evaluate inhibitory effect of COX-2, synthetic derivatives of benzothiazine-3-carboxamide were tested with accumulation of prostaglandin by lipopolysaccharide in aspirin-treated murine macropharge cell. Some of the synthesized lead compounds have potentially shown the structure-activity relationship for selectivity of COX-2 inhibition activity.

• 한국게임학회 논문지
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• 제1권1호
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• pp.73-79
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• 2001

The objective of this paper is to systematically establish the development of game software through the fusion of game implementation and component methodology. The development of game software has inconsistently accomplished without the consistent frame for the analysis and design of game development in the domestic environments. Therefore in case of the development of game software based on game component, although a lot of resources were required in the initial the accumulation of experience and the technology of reuse lead to the efficiency of the maintenance ultimately.

• Geomechanics and Engineering
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• 제34권5호
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• pp.481-489
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• 2023

Drained cyclic triaxial tests were conducted on a saturated sand to examine its deformation characteristics under either axial or lateral cyclic loading condition. To apply lateral cyclic loading, the cell pressure was cycled while maintaining a constant vertical stress. The strain accumulations and flow direction in the soil were presented and discussed considering various initial stress ratios (η₀), cyclic stress amplitudes and cyclic stress paths. The results indicate that axial strain accumulation shows an exponential increase with the maximum stress ratio (η^max). The initial deviatoric stress has comparable effects with lateral cyclic stress amplitude on the accumulated axial strain. In contrast, the accumulated volumetric strain is directly proportional to the lateral cyclic stress amplitude but not much affected by η₀ values. Due to the anisotropy of the soil, the accumulated axial and lateral bulging strains are greater in lateral cyclic loading when compared to axial cyclic loading even though η^max is the same. It is also found that η^max affects soil's lateral deformation and increasing the ratio could change the lateral deformation from contraction to bulging. The flow direction depends on η^max in the sand under lateral cyclic loading, regardless of η₀ values and the cyclic stress amplitudes, and a large η^max could lead to great deviatoric strain but a little volumetric strain accumulation.

• Environmental Engineering Research
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• 제15권1호
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• pp.35-40
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• 2010

Bung Boraphet is the largest freshwater reservoir in Thailand. This study examined the accumulation of copper (Cu) and lead (Pb) in water, sediment and tissues of Asian clams (Corbicula sp.) within Bung Boraphet to assess the possible polluting effect of soil erosion and the dissolution of water soluble salts from the Nan River. Samples were collected from 12 study sites within Bung Boraphet between February and December 2008. The physicochemical parameters of the water including temperature, pH, turbidity, ammonia nitrogen, nitrate nitrogen, orthophosphates, biochemical oxygen demand, dissolved oxygen, Cu, and Pb were measured. The water in Bung Boraphet was found to be medium clean according to the surface water quality standard of Thailand. The levels of Cu and Pb in the water were low but heavy metals were detected at higher levels in the sediment and tissues of Corbicula sp. In the near future, management practices and regulator approaches for Cu and Pb contamination will be needed to protect the water in Bung Boraphet.

• Nuclear Engineering and Technology
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• 제51권2호
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• pp.546-555
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• 2019

Since the first nuclear reactor first critical, nuclear systems has gone through four generations of history, and the fourth generation nuclear system will be truly realized in the near future. The notions of SVBR and lead-bismuth eutectic alloy coolant put forward by Russia were well received by the international nuclear science community. Lead-bismuth eutectic alloy with the ability of the better neutron economy, the low melting point, the high boiling point, the chemical inertness to water and air and other features, which was considered the most promising coolant for the 4th generation nuclear reactors. This study mainly focuses on the structural design optimization of the 4th-generation reactor coolant pump, including analysis of external characteristics, inner flow, and transient characteristic. It was found that: the reactor coolant pump with a central symmetrical dual-outlet volute structure has better radial-direction balance, the pump without guide vane has better hydraulic performance, and the pump with guide vanes has worse torsional vibration and pressure pulsation. This study serves as experience accumulation and technical support for the development of the 4th generation nuclear energy system.

• 대한수의학회지
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• 제36권3호
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• pp.709-718
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• 1996

This experiment was carried out to clarify the effect of lead poisoning on the lead and essential trace elements homeostasis of tissues in rats. Fifty female Wistar rats, 7 weeks old, were divided into four experimental groups(B, C, D, and E) and a control(A). The four experimental groups received diets contaminated artificially with 10 (B group), 100 (C group), 1,000 (D group) and 5,000 (E group) ${\mu}g/g$ of lead as lead acetate, respectively. The control group received normal diet. Rats were necropsied on the 4th or 8th week of experimental periods and heart, liver, spleen, kidney, muscle, lung and hair were taken. The tissues were analysed for lead, copper, zinc, iron and calcium content by atomic absorption spectrophotometry. From these experiments following results ware obtained ; In C group, lead content of the heart, liver, kidney and hair were significantly increased both on the 4th and 8th week of experiment. In D and E group, lead content of all tissues including heart, liver, spleen, kidney, muscle, hair and lung were significantly increased in accordance with the lead contamination both on the 4th and 8th week of experiment. In C group, copper content of tissues were significantly increased in the heart, liver, kidney and lung on the 4th week and all tissues on the 8th week of experimental periods. In D and E group, copper content of the liver were significantly increased both on the 4th and 8th week of experiment. But the copper content of tissues were gradually decreased compared with C group in accordance with the lead contamination. Especially the content in spleen, heart or kidney were significantly decreased compared with the control group. The zinc content of kidney, heart, or spleen were decreased in D and E groups whereas the iron and calcium content showed no significant change.

• Toxicological Research
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• 제24권3호
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• pp.227-233
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• 2008

To detect lead ions using electrochemical voltammetric analysis, Infrared Photo-Diode Electrode(IPDE) was applied via cyclic and square wave stripping voltammetry. Lead ions were deposited at 0.5 V(versus Ag/AgCl) accumulation potential. Instrumental measurements systems were made based on a simple and compact detection system. The stripping voltammetric and cyclic voltammetric optimal parameters were searched. The results yielded a cyclic range of $40{\sim}240mgl^{-1}$ Pb(II) and a square wave stripping working range of $0.5{\sim}5.00mgl^{-1}$ Pb(II). The relative standard deviation at 2 and 4 $mgl^{-1}$ Pb(II) was 0.04% and 0.02%(n=15), respectively, using the stripping voltammetric conditions. The detection limit was found to be 0.05 $mgl^{-1}$ with a 40 sec preconcentration time. Analytical interference ions were also evaluated. The proposed method was applied to determine lead ions in various samples.

• 한국환경농학회지
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• 제28권2호
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• pp.146-157
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• 2009

The influence of Pb-citrate complex formation on Pb uptake and the effect of Pb on organic acid exudation were investigated using four plant species, viz., sunflower (Helianthus annuus L), Indian mustard (Brassica juncea), canola (Brassica napus) and vetiver grass (Vetiveria zizanioides) under hydroponic conditions. Seedlings were exposed to different levels of Pb and Pb-citrate for 24 hrs and subsequently Pb distributions in plant shoot, root and hydroponic solution were measured. The dissolved organic carbon (DOC) concentration generally decreased as the concentration of Pb in the hydroponic solution increased. In contrast to DOC, the total organic acid concentrations exuded from Indian mustard roots significantly increased (424 to 6656 mg $kg^{-1}$) with increased Pb treatment, implying that exuding organic acids were involved in Pb accumulation in Indian mustard. The complexation of Pb with citrate enhanced Pb accumulation in the above ground portions. Lead concentration in Indian mustard increased from 2.05 mg $kg^{-1}$ to 6.42 mg $kg^{-1}$ when the concentration of citrate in solution increased from 0 to 50 mg $L^{-1}$. This result showed enhanced translocation of Pb from root to shoot with observation of transfer coefficient ($K_t$) increase from 2.03E-3 to 5.72E-3.