• 대한치과기공학회지
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• 제28권1호
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• pp.27-41
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• 2006

The physical property and phase transformation in a commercial dental casting high gold alloy was investigated as a function of ageing temperature and time using microvickers hardness tester, X-ray diffraction, optical and electron microscopy and EPMA analyser. 1. With increasing ageing time, the hardness of solution-treated gold alloys increased slowly at the initial stage of ageing treatment at an ageing temperature of $300{\sim}400^{\circ}C$, and it reached a maximum value of hardness at the medium stage. Finally, it decreased gradually during further ageing. The maximum value of hardness at was similar with that of the conventional materials and suitable for using as the crown & bridge. 2. During isothermal ageing at a temperature range of $300{\sim}400^{\circ}C$, three phases consisting of the Au-rich ${\alpha}_1$phase with a face-centered cubic structure, the Pt3Zn ${\alpha}_2$phase with an ordered AuCu3(L12) type(f.c.c.) and the Pt-rich ${\alpha}_3$phase with face-centered cubic structure in solution-treated gold alloys were transformed into different three phases consisting of the ${\alpha}_1$phase, the ${\alpha}_3$phase and the PtZn $\beta$phase with an ordered AuCu I(L10) type. 3. The hardening of gold alloys was attributed to the lattice strains of the matrix resulting from the transformation of the ${\alpha}_2$phase to the $\beta$phase. 4. The softening of gold alloys during over-ageing was attributed to the coarsening of the nodules consisting of the $\beta$phase and ${\alpha}_1$matrix.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.482_483
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• 2009

This paper presents a method of finding the optimal operating point minimizing a given objective function with 3 phase power flow equations and operational constraints, called 3 phase optimal power flow. 3 phase optimal power flow can provide operation and control strategies for the distribution systems with distributed generation assets, which might be frequently in unbalanced conditions assuming that high penetration rate of renewable energy sources in the systems. As the solution technique, this paper adopts a standard particle swarm optimization (PSO).

• 열처리공학회지
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• 제21권5호
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• pp.251-258
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• 2008

A transmission electron microscope investigation has been performed on the morphology of dislocations in deformed ${\gamma}^{\prime}-Ni_3(Al,Ti)$ alloys containing fine dispersion of disordered ${\gamma}$ particles. Superlattice dislocations dissociate into fourfold Shockley partial dislocations in a uniform supersaturated solid solution of the ${\gamma}^{\prime}$ phase. Dislocations are attracted into the disordered ${\gamma}$ phase and dissociate further in the particles. At any stage of aging, dislocations cut through the particles and the Orowan bypassing process does not occur even in the over-aged stage of this alloy system. The work necessary to pull the dislocation away from the disordered particles into the ordered matrix should mainly contribute to increase the strength of the ${\gamma}^{\prime}$ phase containing fine dispersion of the disordered ${\gamma}$ phase.

• Investigative Magnetic Resonance Imaging
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• 제17권4호
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• pp.259-266
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• 2013

목적: DTPA-bis-amide (L3) Gd(III) 복합체의 약동학 및 생체내 분포특성을 조사하고자 하였다. 대상과 방법: Sprague-Dawley 쥐의 꼬리정맥을 통하여 0.1 mmol Gd/kg의 DTPA-bis-amide (L3) Gd(III) 복합체를 주사한 후 약동학 및 생체내 분포 특성을 조사하였다. 조직 및 장기 그리고 혈중 Gd 농도를 ICP-AES를 사용하여 정량 측정하였으며 혈중 약동학적 파라미터는 two-compartment 모델을 사용하여 계산하였다. 결과: DTPA-bis-amide (L3) Gd(III) 복합체의 혈중 반감기는 ${\alpha}$-phase의 경우 $2.286{\pm}0.11$ min 그리고 ${\beta}$-phase의 경우 $146.1{\pm}7.5$ min 이었다. 생체내 분포특성은 주요 배설 경로는 신장을 통한 배설이 주요 경로였으며 일부 담도계를 통한 배설이 확인되었다. 또한 Gd(III)의 농도비는 다른 장기에 비해 간과 비장에서 매우 높은 농도를 보였으며 일부 Gd(III)이 정맥주사 후 7일후에 혈액 및 일부 장기에서 매우 소량 검출되었다. 결론: 새로운 조영제인 DTPA-bis-amide (L3) Gd(III) 복합체는 혈중 잔류시간이 상대적으로 길면서도 체내 축적없이 체외로 배출되는 특성을 나타내었다. 따라서 친지질성과 친수성의 균형이 잘 이루어진 가돌리늄 조영제의 합성은 향후 blood pool MRI 조영제로써의 가능성이 매우 높은 것으로 판단된다.

• 전자공학회논문지A
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• 제33A권3호
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• pp.152-162
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• 1996

Diffraction gratings were designed to generate multiple beams for the real-time optical interconnection in free-space using a liquid crsytal television. Multi-level phase gratings consisted of stepped phase value, 0 to 2$\pi$, and generate a 5$\times$5 spot array, and V-shaped spot patterns which have a maximum diffraction efficiency of 78.84%. Simulated annealing technique was used to determine phase states of each pixel having uniform intensity and high diffraction efficiency. Through the optical interconnection experiments, we compared the diffraction characteristics of beam paterns obtained by binary-level, four-level, and eight-level phase gratings.

• Archives of Pharmacal Research
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• 제27권5호
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• pp.539-543
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• 2004

An efficient analytical method was devised for the accurate L-muscone assay in aqueous samples. It involves solid-phase extraction of L-muscone in adsorption mode using XAD-4 as the sorbent and dichloromethane modified with 10% (v/v) methanol as the eluting solvent. The gas chromatographic analysis of the eluate residue dissolved in toluene on a DB-5MS capillary column provided complete resolution of L-muscone from the co-extracted interferences. The overall method showed excellent linearity ($r^2{\geq}$ 0.9994) in the range of 0.1 to 2.0 $\mu\textrm{g}$/mL with good intra- and inter-day precisions (% RSD = 2.5～7.3) and with high extraction recovery rates ($\geq$ 98.1 %). When the present method was applied to a L-muscone herbal drink product, the within-batch RE (%) in the labeled concentration (1.5 $\mu\textrm{g}$/mL) for the three randomly chosen bottles were -2.4, -1.3 and -3.3 with high precision (% RSD $\leq$ 3.1). The present method is considered to be suitable for quality control evaluation on liquid drinks and other complex formulations fortified with L-muscone.

• KSBB Journal
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• 제15권1호
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• pp.100-105
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• 2000

국내에서 서식하고 있는 곤충병원성 선충 Stemernema Carpocapsae로 부터 분리$\cdot$동정된 Xenorhabdus nematophilus를 대상으로 최적배지조성과 배양조건, 상변화 특성 및 곤충 독성물질 역기를 조사하였다. 균주의 최적배치 조성은 50-70g/L yeast extract, 3 g/L $K_{2}HPO_{4}$, 1g/L $NH_{4}H_{2}PO_{4}$, 2g/L ${MgSO}_4$$\cdot$${7H}_{2}O$,10g/L NaCl 이였으며, yeast extract의 농도가 균주성장 제한인자로 작용하였다. Yeast extract 농도에 대한 비성장속도의 의존도를 Monod equation을 가정하여 비교해 본 결과, 최대 비성장속도는 0.13 $ht^{-1}$이고 Monod 상수값은 20 g/L였다. 배양 배치의 pH는 초기 6-7에 관계없이 성장이 진행됨에 따라서 약 8.5-9.5까지 증가하였으며, 7L fermentor배양에서는 균주의 비성장속도가 약 0.18 $ht^{-1}$로 flask배양보다 1.4배 더 증가하였다. 상변화의 경우 정지기에서도 fermentor배양과 flask배양 모두 약 90% 이상 phase I이 유지되었다. 한편 꿀벌부채명 나방에 대한 구강독성을 시험해 본 결과, X. nematophilus 균주를 유충사료에 첨가하면 꿀벌부채명나방 유충의 정상적인 성장을 저해하였으며, 20여일 경과 후 완전히 유충을 사멸시키는 것을 확인하였다. 배양 상등액을 유충에 직접 주사하였을 때 배양 24 시간인 지수성장기 초기에 가장 독성이 강하였으며, 배양시간이 경과함에 따라 독성이 점차 감소하였다.

• 대한수의학회지
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• 제35권3호
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• pp.447-458
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• 1995

This study was carried out to characterize nonadrenergic, noncholinergic(NANC) relaxation of porcine retractor penis(PRP) muscle induced by electrical field stimulation(EFS) and to investigate the actions of niric oxide(NO) and vasoactive intestinal polypeptide(VIP) as candidates for NANC neurotransmitters. Biphasic relaxations of PRP muscle were induced by EFS to NANC nerve. Rapid-phase relaxation was observed at low frequency(0.5-16Hz) and slow-phase relaxation followed during high frequency(8-60Hz). Both relaxations were frequency-dependent and TTX($1{\times}10^{-6}M$)-sensitive. L-NAME($2{\times}10^{-5}M$) inhibited the rapid-phase relaxation, but not the slow-phase relaxation. The inhibition of the rapid-phase relaxation with L-NAME was reversed by L-arginine ($1{\times}10^{-3}M$) but not by D-arginine($1{\times}10^{-3}M$). Methylene blue($4{\times}10^{-5}M$) reduced the rapid-phase relaxation. Exogenous No(ExoNO, $1{\times}10^{-5}-1{\times}10^{-4}M$) induced dose-dependent relaxations of PRP muscle. Oxyhemoglobin($5{\times}1^{-5}M$) blocked the relaxation induced by ExoNO and inhibited EFS-induced relaxation. Hydroquinone($1{\times}10^{-4}M$) also abolished the relaxation induced by ExoNO, but did not affect EFS-induced relaxation. L-NAME resistant slow-phase relaxation to EFS was inhibited by ${\alpha}$-chymotrypsin(2.5 U/ml). Both methylene blue($4{\times}10^{-5}M$) and Nethylmaleimide($1{\times}10^{-4}M$) reduced the slow-phase relaxation by EFS. [4-Cl-D-$Phe^6$, $Leu^{17}$]-VIP($3{\times}10^{-6}M$) inhibited the slow-phase relaxation by EFS. External applications of VIP ($1{\times}10^{-7}M$) caused relaxations that were simillar to the L-NAME resistant slow-phase relaxations induced by EFS, and relaxant effects of exogenous VIP were blocked by ${\alpha}$-chymotrypsin(2.5 U/ml).

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권1호
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• pp.24-31
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• 1998

The separation and concentration of L-phenylalanine (L-Phe) using a supported liquid membrane (SLM) is investigated. A cation complex agent, di-2-ethylhexyl phosphoric acid (D2EHPA), is used as a carrier in the SLM with n-Heptane as a solvent. The reaction order and equilibrium constant in the formation reaction of L-phe-carrier complex are obtained from the extraction experiment. A mathematical model for a carrier mediated counter transport process is proposed to estimate the diffusion coefficient of L-phe-carrier complexly in the liquid membrant. Permeation experiments of L-phe using a SLM are performed under various operating conditions and optimum conditions for the transport of L-phe are obtained. Concentration of L-phe in the strip phase against its concentration is observed. Transport rate of glucose through liquid membrane is less than that of L-phe in the competitive transport of L-phe and glucose. And the existence of glucose reduced the transport rate of L-phe. The performance of separation with continuous strip phase is increased due to the dilution effect in the strip phase.

• 한국물환경학회지
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• 제27권3호
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• pp.329-333
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• 2011

흡착제로서의 PBO 섬유가 수용성 알킬페놀 화합물의 고상 추출용으로 사용되었다. 초기농도 $100{\mu}gL^{-1}$ 에서 10 종류의 알킬페놀에 대한 제거율은 16.8~96.3%였고, 제거율은 섬유무게/액체부피비의 증가에 따라 증가하였다. log K는 log P와 일치하였다. 흡착된 알킬페놀은 아세트니트릴과 디클로로메탄의 혼합액으로 충분히 탈착되었다.