• 분석과학
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• 제13권2호
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• pp.151-157
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• 2000

수소화물 발생법-원자흡수 분광계를 이용한 비소의 분석에서 금속이온의 은폐제로 사용되는 L-cysteine, thiourea, KI/ascorbic acid 등의 예비 환원제와 염산, 질산, 황산 및 이들의 1:1 혼산의 종류 및 농도가 비소의 분석에 미치는 영향을 비교 연구하였다. 대부분의 예비 환원제의 경우 3-5M 이상의 고농도 산 용액에서 비소에 대한 높은 흡괌도를 나타냈으나, 0.1M 이하의 낮은 산 용액에서는 L-cysteine을 제외하고는 극히 저조한 흡광도를 나타내었다. 질산 산성용액에서는 흡광도 신호의 불안정성이 심하였다. 방해물질로서 $Cr^{6+}$, $Br^{5+}$ 이온의 방해영향이 크게 관찰되었지만, 이때 예비 환원제는 수소화물 생성을 크게 증가시켰다.

• Journal of Radiation Protection and Research
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• 제33권1호
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• pp.35-40
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• 2008

석유화학 공정의 증류탑은 공정유체를 분리, 정제하는 중요한 장치 중의 하나로 가동효율은 설비의 생산성에 큰 영향을 미친다. 본 연구는 밀봉 감마선원을 이용하여 투과 감마선의 세기를 높이별로 측정함으로써 내부 밀도의 변화를 분석하여 공정의 가동 중 내부 상황에 대한 정보를 얻고자 하였다. 이를 위하여 한국원자력연구원에서 개발된 자동 증류탑 검사장치를 이용하여 증류탑 상부 양쪽에 밀봉 감마선원과 방사선검출기를 매달아 수직으로 내리면서 실험을 수행하였으며, 이때 감마선원으로는 Co-60 150 mCi과 방사선검출기로 BGO detector를 각각 사용하였다. 진단결과 설비 내부의 tray에는 구조적 결함이 관찰되지 않았으나, 유체분포를 고려할 때 상부는 기포층(vapor)의 밀도분포가 지배적인 반면에, 하단부에는 기포에 비해 유체가 상대적으로 많이 분포하는 것으로 계측되었다. 본 실험으로부터 밀봉 감마선원을 이용한 가동 중에 있는 대형 증류탑의 tray에 대한 구조적 건전성 및 내부 유체분포에 대한 정보를 성공적으로 제시하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.225.1-225.1
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• 2010

Within recent years attention has been focused on the method of hydrogen storage using metal hydride reactor due to its high energy density, durability, safety and low operating pressure. In this paper, a numerical study is carried out to investigate the coupled heat and mass transfer process for absorption in a cylindrical metal hydride hydrogen storage reactor using a newly developed model. The simulation results demonstrate the evolution of temperature, equilibrium pressure, H/M atomic ratio and velocity distribution as time goes by. Initially, hydrogen is absorbed earlier from near the wall which sets the cooling boundary condition owing to that absorption process is exothermic reaction. Temperature increases rapidly in entire region at the beginning stage due to the initial low temperature and enough metal surface for hydrogen absorption. As time goes by, temperature decreases slowly from the wall region due to the better heat removal. Equilibrium pressure distribution appears similarly with temperature distribution for reasons of the function of temperature. This work provides a detailed insight into the mechanism and corresponding physicochemical phenomena in the reactor during the hydrogen absorption process.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.943-946
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• 2011

The electronic absorption and surface morphology evolution of two types of molecular double layer thin films, copper phthalocyanine (CuPc) layer deposited on chloro[subphthalocyaninato]boron(III) (SubPc) layer, denoted as SubPc/CuPc, and vice versa, with various thicknesses were investigated using ultraviolet (UV)-visible spectroscopy and atomic force microscopy (AFM). Both types of double layer structures showed similar broadened absorption patterns in the UV-visible region that were consistent with the fitted spectra following simple linear combination of the single layer absorption spectra of the two materials. In contrast, the surface morphology of double layer structures was dependent on the order of deposition. For the CuPc/SubPc structures, surface morphology was characterized by elongated grains, which are characteristic of SubPc thin films, indicating that the morphological influence of the underlying CuPc layer on the subsequent SubPc layer was not large. For the SubPc/CuPc structures, however, the underlying SubPc layer acted as a morphological template for the subsequently deposited CuPc layer. It was also observed that the grain size of the CuPc layer varied according to the thickness of the underlying SubPc layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.133-137
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• 2004

In this paper, we investigated impurities content, absorption properties, and thermal properties showing by changing the content of carbon black which is semiconductive materials for underground power transmission. Specimens were made of sheet form with the three of existing resins and the nine of specimens for measurement. Impurities content of specimens and absorption properties were measured by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer) and Karl Fisher. And high temperature, heat degradation initiation temperature, and heat weight loss were measured by TGA (Thermogravimetric Analysis). The dimension of measurement temperature was 0$[^{\circ}]$ to 800$[^{\circ}]$, and rising temperature was 10$[^{\circ}/min]$. Impurities content was highly measured according to increasing the content of carbon black from this experimental result also absorption amount was increased according to these properties. Specially, impurities content values of the A1 and A2 of existing resins were measured more than 4000[ppm]. Heat degradation initiation temperature from the TGA results was decreased according to increasing the content of carbon black. All over, heat stabilities were EEA>EBA>pEVA. That is, heat stabilities of EVA containing the weak VA(vinyl acetate) against heat was measured the lowest.

• 대한수의학회지
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• 제9권2호
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• pp.49-53
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• 1969

The distribution of radiophosphorus ($^{32}P$) was observed in three groups of female Albino tat consisted of early pregnancy group (10 days of pregnancy), late pregnancy group (18 days of pregnancy) and nonpregnanted control group. The results obtained were as follows: 1. The various sites arranged in the descending of absorption rate of $^{32}P$ were femur, mandible, liver, spleen, ovary, fetus (only from early pregnancy group) and kidney in both groups of non-pregnanted and early pregnancy and femur, mandible, fetus, liver, ovary, spleen and kidney in the late pregnancy group. 2. The significant difference (P<0.05) in the absorption rate was found between femur and mandible in the early pregnancy group. 3. The absorption rate of fetus from late pregnancy group was significantly (P<0.01) higher than that of fetus from the early pregnancy group. 4. The high absorption rate was observed with femur and mandible in both groups of non-pregnanted and early pregnancy. 5. The significantly (P<0.01) high absorption rate was observed with ovary and fetus from the late pregnancy group.

• Journal of Radiation Protection and Research
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• 제26권3호
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• pp.287-290
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• 2001

The 9.17MeV gamma-rays from the $^{13}C(p,\;{\gamma})^{14}N,\;^{14}N({\gamma},\;{\gamma})^{14}N$ reactions were measured. The incident 9.17MeV gamma-ray was produced from the $^{13}C(p,\;{\gamma})^{14}N$ reaction at Ep=1.75MeV resonance. The 1.75MeV proton beam was accelerated using the 3MV SNU-AMS Tandetron and 1.7MV KIGAM Tandem accelerators. The enriched 13C target was $121{\mu}g/cm^2$ self-supporting foil, and we used liquid nitrogen as a resonant absorption target. We used a HP-Ge detector with 30% efficiency and less 2keV energy resolution. We developed new method to detect the scattered 9.17MeV gamma-ray from the nitrogen target by using the energy difference between the Doppler shifted gamma-ray from the $^{13}C(p,\;{\gamma})^{14}N$ reaction and the resonant absorbed and rescattered gamma-ray from the $^{14}N({\gamma},\;{\gamma})^{14}N$ reaction.

• Nuclear Engineering and Technology
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• 제38권7호
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• pp.675-680
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• 2006

The neutron transmutation doping of silicon (NTD), as a method to produce a high quality semiconductor, utilizes the transmutation of a silicon element into phosphorus by neutron absorption in a silicon single crystal. In this paper, we present the design of a neutron screen for a 6' Si ingot irradiation in the NTD2 hole of HANARO. The goal of the design is to achieve an even flat axial distribution of the resistivity, or $Si^{30}(n,{\gamma})Si^{31}$ reaction rate, in the irradiated Si ingot. We used the MCNP4C code to simulate the neutron screen and to calculate the reaction rate distribution in the Si ingot. The fluctuations in the axial distribution were estimated to be within ${\pm}2.0%$ from the average for the final neutron screen design; thus, they satisfy the customers' requirement for uniform irradiation. On the other hand, we determined the optimal insertion depths of the Si ingots by varying the critical control rod position, which greatly affects the axial flux distribution.

• 한국농공학회논문집
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• 제52권3호
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• pp.39-45
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• 2010

Quantification of carbon absorption and understanding the human induced land use changes (LUC) forms one of the major study with respect to global climatic changes. An attempt study has been made to quantify the carbon absorption by LUC through remote sensing technology. The Landsat imagery four time periods was classified with the hybrid classification method in order to quantify carbon absorption by LUC. Thereafter, for estimating the amount of carbon absorption, the stand biomass of forest was estimated with the total weight, which was the sum of individual tree weight. Individual tree volumes could be estimated with the crown width extracted from digital forest cover type map. In particular, the carbon conversion index and the ratio of the $CO_2$ molecular weight to the C atomic weight, reported in the IPCC guideline, was used to convert the stand biomass into the amount of carbon absorption. Total carbon absorption has been modeled by taking areal estimates of LUC of four time periods and carbon factors for land use type and standing biomass. Results of this study, through LUC suggests that over a period of construction, 7.10 % of forest and 9.43 % of barren were converted into urban. In the conversion process, there has been a loss of 6.66 t/ha/y (7.94 %) of carbon absorption from the study area.

• 한국광학회지
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• 제11권5호
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• pp.301-305
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• 2000

세슘 $D_2$의 F=4$\longrightarrow$ F'=5 전이선에서 전자기-유도-흡수(EIA) 현상을 조사하였다. 축퇴된 2준위 원자계의 공명 주파수에서 발진하는 두 레이저광과 원자매질에서 결맞음 상호작용에 기인한 원자흡수의 급격한 증가를 보았다. 세슘원자에서 EIA가 가능한 조건을 조사하였으며 이러한 흡수 신호의 크기는 레이저 선폭이 좁을수록, 결합광의 세기가 클수록 현저하였다. 또한, 결안맞는 레이저에 의한 펌핑이 있는 경우에 흡수 신호가 증폭되는 것을 볼수 있었다.