• 대한화학회지
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• 제48권5호
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• pp.504-509
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• 2004

구리 금속 분말과 혼합 알칼리금속 다셀레늄화물 용융염 ($KNaSe_x$) 과의 반응을 통하여 판상형태의 결정을 갖는 $KCu_4Se_3$ 화합물을 얻었다. $KCu_4Se_3$화합물의 구조는 X-선 단결정 회절법에의해 결정되었으며 사반면상을 갖는다. (P4/mmm, a=4.013(1)${\AA}$, c=9.712(1)${\AA}$, z=1, R=6.7%). 그 구조는 안티 PbO 구조를 갖는 $Cu_2Se_2$ 층이 겹쳐짐으로서 만들어지는 $[Cu_4Se_3]_n^{n-}$의 이중층으로 구성되어있다. $KCu_4Se_3$의 단결정에 대한 온도 변화에 따른 저항 측정을 통하여 전도체의 특성을 확인하였으며 300 K에서 $1.8{\times}10^{-4}{\Omega}{\cdot}cm$과 20 K에서 $1.0{\times}10^{-6}{\Omega}{\cdot}cm$의 저항 값을 갖는다.

• 대한방사선기술학회지:방사선기술과학
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• 제31권3호
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• pp.223-228
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• 2008

의학적으로 방사선을 사용 시 가장 중요한 점은 환자의 병을 진단 가능하되 피폭선량을 최소화시켜야 한다는 점이다. 진단용 X-선 중 장파장부분은 대부분 흡수에 관여하게 되어 환자의 피폭선량을 증가시키므로 불필요하다. 이러한 장파장영역을 제거하기 위한 방법으로 가장 효과적인 방법은 여과 판의 사용이다. 이에 부가여과가 없는 경우와 0.3mmCu filter 사용 시의 화질과 피부입사선량에 대해 실험을 해 보았다. ROC 신호용 지름 4mm, 두께 3mm의 아크릴 디스크를 chest phantom에 랜덤하게 위치시키면서 non filter 및 Cu filter시 각 각 20매씩 총 40매의 신호+잡음영상을 촬영하고, 또한 신호가 없는 영상(잡음만의 영상)을 각 각 20매씩 40매 촬영하여 총 80매의 영상을 준비한 후 5명의 방사선종사자가 판독 후 P(S/s), P(S/n) 구하여, ROC곡선을 그리고, 감도와 특이도 및 곡선하면적을 구해 평가하였다. 또한 AAPM(American Association of Physicists in Medicine by the American Institute of Physics)권고에 따른 ANSI chest phantom과 Contrast-detail phantom을 이용하여 non filter 또는 Cu filter사용 시 시각적으로 관찰 가능한 병소의 갯수를 파악하였으며, 또한 두 경우에서 피부입사선량을 측정하였다. 그 결과 Cu filter사용 시에 ROC곡선이 좌상방향에 위치하고, 감도, 곡선하면적 및 CD phantom 병소의 갯수에서 모두 좋은 결과를 나타내었다. 또한 피부입사선량은 감소가 되어 여러 측면에서 부가필터의 사용을 검토해 볼 필요가 있으리라 사료된다.

• Archives of Pharmacal Research
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• 제12권2호
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• pp.119-124
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• 1989

Cotton xanthate, which was obtained by treating cotton with carbon disulfide in alkaline solution, was treated with the solution of polyvalent metal ions to produce cotton xanthate-metal chelates. This chelation reaction was readily and simply achieved, and antimicrobial agents with suitable structures could subsequently be coupled to the chelate with ease at moderate pH values and in aqueous solution. Metal ions used in present work include Cu(II), Zn(II) and Fe(III). Tetracycline, streptomycin, neomycin and pyrithion were used as antimicrobial/antifungal agents. Antibacterial activities were measured employing ditch plate method against G(+) Staphylococcus aureus, Streptococus faecalis, and G(-) Escherichia coli, Enterobacter aerogenes, and the fungus, Aspergillus niger. All the cotton xanthate-metal-antimicrobial agent chelates exhibited activities whereas the cotton xanthate-metal chelates themselves were inactive. Considering the extensive washing procedures and results from control experiments, possibility of the involvement of physical adsorption for the binding of drugs could be excluded.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제23회 춘계학술대회
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• pp.93-98
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• 1996

Friction and wear characteristics of metals in dry and boundary lubricated sliding conditions are observed experimentally using pin-on-disk and pin-on-plate type tribotesters. The motivation of this research is to investigate the effect of sliding history on the tribological behavior of metals. Cu and SM45C steel materials were used for the experiment. The results show that in dry condition the fictional behavior as well as wear of the specimens differed between uni-directional and bi-directional sliding conditions. The friction coefficient values, wear profile and optical micrograph of the wear track are presented.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.229-229
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• 2012

Adhesion of Copper film on the aluminum oxide layer formed by anodizing an aluminum plate was enhanced by applying ion beam mixing method. Forming an conductive metal layer on the insulating oxide surface without using adhesive epoxy bonds provide metal-PCB(Printed Circuit Board) better thermal conductivities, which are crucial for high power electric device working condition. IBM (Ion beam mixing) process consists of 3 steps; a preliminary deposition of an film, ion beam bombardment, and additional deposition of film with a proper thickness for the application. For the deposition of the films, e-beam evaporation method was used and 70 KeV N-ions were applied for the ion beam bombardment in this work. Adhesions of the interfaces measured by the adhesive tape test and the pull-off test showed an enhancement with the aid of IBM and the adhesion of the ion-beam-mixed films were commercially acceptable. The mixing feature of the atoms near the interface was studied by scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy.

• Journal of Pharmaceutical Investigation
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• 제18권3호
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• pp.107-111
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• 1988

Zr, Cu, Zn and Fe-pyrithione complexes were prepared in aqueous medium and their antimicrobial activities were evaluated by MIC and cylinder plate methods against Bacillus subtilis, Sarcina lutea, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Trichophyton mentagrophytes, Candida albicans, Asperillus niger and Saccharomyces cerevisiae. Zr-pyrithione possessed most potent activities among the metal complexes against a wide range of microorganisms, especially Gram positive, B. subtilis, S. aureus and fungus, C. albicans. And all of the metal complexes synthesized were more active than pyrithione base. Fe(III)-pyrithione complex has an equal potency to Zn-pyrithione in general but it showed potent activity against B. subtilis microorganism than Zn-pyrithione.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.961-963
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• 2002

Organic electroluminesencent device have been studied because of its easy fabrication and high brightness for plate panel display instead of cathode ray tube. There are some device structure for full color filter system can be applicable to the full color application if the blue light organic electroluminesencent device(OELD) is developed. In this study, we fabricated OELD of ITO/CuPc/PBD/LiF/Al using mixed of 500, 600, $700[{\AA}]$ by vacuum method as a emitting layer. We studied the voltage-current, voltage-luminance characteristics and blue light emission of OELD,

• Tribology and Lubricants
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• 제14권1호
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• pp.45-53
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• 1998

Friction and wear test for two kinds of Cu-based sintered metallic friction material against cast iron disk was carried out by plate-on-disk type friction and wear tester to investigate the friction and wear characteristics of brake system in severe condition. In this experimental study, the counter specimen was cast iron which is being used generally in brakes of heavy duty equipments. Test friction materials were A type which was manufactured by foreign company and B type by domestic company. Friction coefficient and wear volume were measured and compared with each other. The experiment was performed under room temperature. The worn surface of cast iron disk and friction material were observed by scanning electron microscope. The temperature of surface of disk was measured continuously by the non-contacting thermometer. It was found that A type friction material had stable friction coefficient over the wide range of sliding condition, but B type friction material had unstable friction coefficient and lower value of 0.2 under the severe sliding condition.

• 설비공학논문집
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• 제19권4호
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• pp.328-332
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• 2007

A superconducting magnetic energy storage (SMES) system has shorter response time and longer life time, and is more economical, and environment-friendly than other uninterruptible power supply (UPS). A conduction cooling system is well answer for the high temperature superconductor (HTS) SMES system. Because the conduction cooling system is simple, light and small structure. The purpose of this paper is to design and verify the effective conduction cooling system for the HTS SMES system. The analysis of heat loads in cryostat is performed. Thermal shield heat loads, temperatures of HTS coil surface and conduction Cu plate are estimated and measured.

• Nuclear Engineering and Technology
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• 제48권4호
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• pp.906-914
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• 2016

We investigated the heat load imposed on the lower head of a reactor vessel by the natural convection of the oxide pool in a severe accident. Mass transfer experiments using a $CuSO_4-H_2SO_4$ electroplating system were performed based on the analogy between heat and mass transfer. The $Ra^{\prime}_H$ of $10^{14}$ order was achieved with a facility height of only 0.1 m. Three different volumetric heat sources were compared; two had identical configurations to those previously reported, and the other was designed by the authors. The measured Nu's of the lower head were about 30% lower than those previously reported. The measured angular heat flux ratios were similar to those reported in existing studies except for the peaks appearing near the top. The volumetric heat sources did not affect the Nu of the lower head but affected the Nu of the top plate by obstructing the rising flow from the bottom.