• Analytical Science and Technology
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• v.13 no.3
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• pp.309-314
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• 2000

The quantitative analysis of various trace metals including fission products in lithium molten salts has been performed using a inductively coupled plasma atomic emission spectrometer (ICP-AES). The spectral interferences of lithium content, 500, 1,000 and 2,000 mg/L, in the sample solution were investigated using an optimum wavelength for the respective metal species. As a result, the line intensities for Y, Nd, Sr, and La had no influences from the lithium content up to 2,000 mg/L, while Mo, Ba, Ru, Pd, Rh, Zr and Ce showed spectral interferences of 10% to 50%. The group separation of metals from lithium in the molten salts solution was carried out by adding ammonia water into the solution. The recovery of Ru, Y, Rh, Zr, Nd, Ce, La and Eu was found to be over 90%, while Mo, Ba, Pd, and Sr provided low recovery percentages.

• Analytical Science and Technology
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• v.11 no.6
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• pp.485-494
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• 1998

Ternary and quaternary alloys composed of Mo-Ru-Rh-Pd were prepared and their crystal structure and quantitative chemical compositions were analysed by XRD, WDX, EDX and ICP/AES. The results of X-ray diffraction studies showed that the alloys were crystallized in hexagonal close packing, well known as ${\varepsilon}$-phase with $P6_3/mmc$ of space group. The optimum accelerating voltage for Zr~Cd(40~48) analyzed by EPMA using PET crystal was found to be 15 kV and the linear regression coefficient(R) of atomic number and X-ray intensity was approximately 0.998 without Tc standard specimen. The WDX results of alloys of Mo and Pd by linear regression equations were detected to be 0.1% lower compared to WDX analysis results using standard specimen, while Ru, Rh were detected 3% higher. These alloys were completely dissolved in mixed acid of 12.5 mL HCl and 1 mL $HNO_3$, at $220^{\circ}C$ for 22 hours using autoclave with PTFE vessel. There was no reprecipitating phenomnon when diluted 100 times with 1N-HCl. The results of ICP/AES analysis deviated less than 4% comparing with those of normal WDX analysis.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.145-146
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• 2002

Tribological properties of co-sputtered Molybdenum disulfide $(MoS_2)/Carbon\;(C)$ films were studied and compared with those of sputtered $MoS_2$ films. Friction tests were carried out using pin-on-disk friction testers to evluated their friction and wear behaviors in a vacuum ($10^{-5}Pa$), air and humid air of 30, 50, 80% RH. $MoS_2/C$ (14%) composite films exhibited about 9 times longer wear life in a vacuum and about 6 times longer wear life in dry air than $MoS_2$ films did. They also showed stable low friction coefficient of about 0.02 in a vacuum. In humid air, however, $MoS_2/C$ composite films hardly showed good tribological properties.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.217.2-217.2
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• 2012

저궤도위성 관제용 소형안테나시스템의 송수신채널은 저궤도위성의 특성상 안테나구동부의 물리적인 제약조건을 갖으며 이러한 제약조건은 Rotary Joint 포트 수에 의존한다. 다목적 실용위성 5호와 같이 RH 및 LH 편파를 동시 사용하는 위성의 경우 지상안테나의 RF채널은 물리적으로 4포트가 필요하게 된다. 이러한 물리적 채널을 구현하기위해서는 안테나구동부가 대형화될 뿐만 아니라 고비용의 소요된다. 이와 같이 대형화 및 고비용의 단점을 극복하기위하여 Channel Combine Filter를 적용하여 채널이중화를 구현하였으며 단일채널을 갖는 저궤도위성 지상안테나시스템을 RH 및 LH 편파를 동시수신 가능하도록 성능을 개선하였다. 금번 개발된 Channel Combiner는 하나의 물리적 채널을 이용하여 위성으로부터 수신되는 수신신호 및 지상에서 송신하는 송신신호를 동시에 전송하도록 설계한 것으로서 수신되는 신호대비 송신신호의 크기가 상대적으로 고출력이기 때문에 송수신신호간의 간섭영향을 최소화할 수 있도록 설계하였다. 따라서 본 논문에서는 채널이중화를 위하여 개발된 Channel Combiner의 설계방법 및 성능 시험결과에 대하여 상세하게 기술하였으며, 최종적으로 RH 및 LH 편파를 동시에 사용하는 저궤도 위성을 이용한 수신결과에 대하여 기술하였다.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.507-513
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• 1992

Serratia marecescens RH1 isolated from soil samples produced large amount of extracellular proteases. One of the genes encoding an extracellular protease form S. marcescens RH1 was cloned in Escherichia coli by shot gun cloning method. The cloned protease, SSP, was stably expressed by its own promoter and excreted into the extracellular medium from E. coli host (ORF) of 3.135 nucleotides corresponding to 1.045 amino acids (112 kDa). The nucleotide and deduced amino acid sequence of SSP showed high overall homology (88%) to one of the S. marcescens protease (27), but low homology to other serine protease families. The optimal pH and temperature of the enzyme were pH 9.0 and 45.deg.C respectively. The activity of protease was inhibited by phenylmethylsulfonyl fluoride (PMSF), which suggests that the enzyme is a serine protease.

• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.123-133
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• 2005

Objective : We investigated the sasang constitutional difference of physiological and psychological response in various thermal environmental conditions. Methods: Among 210 volunteers, 30 healthy subjects were selected through the QSCC II (a questionnaire for constitutional discrimination) and the manual examination of a specialist in sasang constitution. Subjects consisted of 10 each Soyang(少陽), Soeum(少陰), and Taeum(太陽). Experimental environments were set by six different conditions to be $23^{\circ}C,\;50\%\;RH,\;0.lm/s;\;25^{\circ}C,\;25\%\;RH,\;0.lm/s;\;25^{\circ}C,\;50\%\;RH,\;0.lm/s;\;25^{\circ}C,\;50\%\;RH,\;0.4m/s;\;25^{\circ}C,\;75\%\;RH,\;0.1m/s;\;and\;27^{\circ}C,\;50\%\;RH,\;0.1m\s$ (respectively temperature, relative humidity, and wind velocity). Skin temperature, core temperature, heart rate variability (HRV), and galvanic skin response (GSR) were measured for each subject Additionally, subjects were asked about comfort through the questionnaire. Results: From the viewpoint of external temperature sensibility, in all experimental environments, generally the Taeum type feels hotter and the Soeum feels colder than other types. In relative comfort, Soeum types were most sensitive to wind velocity change. From the viewpoint of body temperature, Taeum type was lower and Soyang was higher than other types. The measurements of HRV and GSR showed no difference between the types. Conclusion : The four sasang constitution types showed different responses to various thermal environmental conditions. Accordingly, our research could provide basic data for building the optimal thermal conditions for individuals based on sasang constitution. Consequently, it will help to build a healthy environment for everyday life.

• Analytical Science and Technology
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• v.16 no.6
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• pp.431-437
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• 2003

Metalization yield of uranium oxide to uranium metal from lithium reduction process of spent pressurized water reactor (PWR) fuels was measured using thermogravimetric analyzer. A reduced metal produced in the process was divided into a solid and a powder part, and each metalization yield was measured. Metalization yield of the solid part was 90.7~95.9 wt%, and the powder being 77.8~71.5 wt% individually. Oxidation behaviour of the quartemary alloy was investigated to take data on the thermal oxidation stability necessary for the study on dry storage of the reduced metal. At $600{\sim}700^{\circ}C$, weight increments of alloy of Mo, Ru, Rh and Pd was 0.40~0.55 wt%. Phase change on the surface of the alloy was started at $750^{\circ}C$. In particular, Mo was rapidly oxidized and then the alloy lost 0.76~25.22 wt% in weight.

• Analytical Science and Technology
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• v.11 no.6
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• pp.421-428
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• 1998

A method has been studied to separate Zr from various fission products in PWR spent nuclear fuels. A solution containing metal ions in place of radioactive fission products was prepared. The Zr was separated with 5 M HCl followed by eluting metal ions such as Ce, Nd, Cs, Rb, Ba, Sr, Ru, Rh, Pd, Ag and Cd with 12 M HCl on Dowex $1{\times}8$, anion exchange resin. The recovery of Zr was more than 95%. The purification of Zr was carried out on anion exchange resin, Dowex $1{\times}8$, in 5 M HCl in order to remove Mo causing isobaric effect during mass spectrometry. The method was applied to separate Zr from a spent PWR fuel. From mass spectrometric measurement, the purified Zr portion was not showed the isobars from other elements such as Mo and Sr.

• Journal of the Korean Society of Radiology
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• v.8 no.4
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• pp.155-161
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• 2014

Mammography is mostly performed by series projection on both breasts. While taking mammography, it is less than average glandular dose of 3 mGy which regulated. But mammography is exposed much more doses actually, due to additional or series projection. Also, it is difficult to recognize around organ dose except exposed breast. Using mathematical simulation of radiation exposure body in mammography, we studied around organ dose distribution by changing thickness(25, 30, $50{\mu}m$) of filter and relative absorption dose rate which set on basis of exposed breast. as a result, when setting of basis of exposed breast, dose of opposite breast is more affected approximately from 79.26 to 86.31%. when using $25{\mu}m$ of filter thickness than $30{\mu}m$, $50{\mu}m$ of filter thickness in Mo/Mo, W/Rh combination which used actually, absorbed dose rates for opposite breast and around organ were low.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.280-284
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• 2016

본 연구에서는 Density functional theory(DFT) 계산을 이용하여, $MoS_2$의 Mo와 S를 다른 원자로 치환 했을 때 $2H-MoS_2$ monolayer의 basal plane에서 HER활성을 향상시켰다. 특히 Ge와 Rh를 치환한 경우, ${\Delta}G_H$가 각각 0.03eV, 0,07eV로 최적에 가까운 HER활성이 나타났다. 다른 원자의 치환이 Fermi level 근처의 DOS(density of states)를 높여, ${\Delta}G_H$을 0에 가깝게 낮출 수 있음을 확인하였다. 또한 치환되는 원자의 농도, 그리고 strain을 변화시켜 농도와 strain의 증가에 따른 ${\Delta}G_H$ 감소를 발견했다. 이로써 각치환되는 원자마다, 치환 농도와 strain을 함께 변화시켜 ${\Delta}G_H$을 낮출 수 있었다. ${\Delta}G_H$가 0에 가까운(${\pm}{\pm}0.2eV$ 이내) 원자종류, 치환 농도, strain의 여러 조합을 찾았다.