• 분석과학
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• 제15권2호
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• pp.115-119
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• 2002

$\alpha$ 및 $\beta$-Cyclodextrin(CD)과 Congo red간의 복합체 형성에 관한 연구를 분광학적 방법으로 조사하였다. 이 결과 cavity 크기가 작은 $\alpha$-CD는 Congo red의 입체적 장애 때문에 복합체를 형성하지 못하였다. 한편 가시광선 영역의 S-형 흡광도 증가 현상으로 볼 때 두 분자의 $\beta$-CD가 한 분자의 Congo red와 equatorial 형태로 복합체를 형성하는 것 같다. 등 흡수점은 346 nm과 478 nm 두 곳에서 나타났다. 온도에 따른 형성상수의 값으로부터 온도가 올라가면 binding energy의 감소로 형성상수가 감소하였다. 열역학적 parameter의 계산 결과 $\Delta$H, $\Delta$S 및 $\Delta$G는 각각 -50.73 kJ/mol, $-108.96J/K{\cdot}mol$ 및 -18.24 kJ/mol 이었다. 따라서 큰 엔트로피 감소를 동반한 자발적 반응임을 알 수 있었다.

• 분석과학
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• 제20권5호
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• pp.406-412
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• 2007

분광 광도법을 이용하여 ${\beta}$-CD와 $[Cu(dien)(sub-py)]^{2+}$ 이온 간의 복합체 형성에 관한 연구를 하였다. ${\beta}$-CD와 $Cu^{2+}$ 착물이 복합체를 형성 할 때 ${\gamma}_{max}$은 리간드에 전자 주는기($CH_3$)가 치환 된 경우는 $^2T_2{\rightarrow}^2E$로 한 곳에서, 전자 끄는기(Cl)가 치환된 경우는 $^2T_2{\rightarrow}^2E$와 MLCT에 의하여 두 곳에서 나타났다. 형성상수는 온도가 올라가면 결합에너지의 감소로 작아졌다. 모든 반응은 엔트로피의 감소를 보였으나 큰 발열반응으로 자발적 반응이었다. 치환기 상수(${\sigma}_x$)에 따른 Hammett plot 결과 좋은 직선성(${\gamma}=0.996$)을 보여 형성상수를 정량적으로 설명할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제31권2호
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• pp.442-446
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• 2010

Adenosine 3',5'-cyclic monophosphate (cAMP) is a second messenger responsible for a multitude of cellular responses. In this study, we utilized $\beta$-cyclodextrin ($\beta$-CD) as an artificial receptor with a hydrophobic cavity to elucidate the inclusion kinetics of cAMP in a hydrophobic environment using the ultrasonic relaxation method. The results revealed that the interaction of cAMP with $\beta$-CD followed a single relaxation curve as a result of host-guest interactions. The inclusion of cAMP into the $\beta$-CD cavity was found to be a diffusion-controlled reaction. The dissociation of cAMP from the $\beta$-CD cavity was slower than that of adenosine 5'-monophosphate (AMP). The syn and anti glycosyl conformations of adenine nucleotides are considered to play an important role in formation of the inclusion complex. Taken together, our findings indicate that hydrophobic interactions are involved in the inclusion complex formation of cAMP with $\beta$-CD and provide insight into the interactions of cAMP with cAMP-binding proteins.

• 대한기계학회논문집
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• 제16권7호
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• pp.1255-1265
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• 1992

본 연구에서는 단열 및 온도가 영으로 고정된 경계조건을 갖는 대칭 입술형과 대칭 익형 강체함유 물상의 접합경계면 균열에 대한 Hilbert 문제로부터 복소 포텐셜 함수와 커스프 균열선단 그리고 접합경계면 균열선단에서 TSIF를 구하고자 한다.

• KSBB Journal
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• 제27권2호
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• pp.109-113
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• 2012

This research was to examine the effects of various cyclodextrins on the solubility and stability of prodigiosin in seawater. Among them, ${\beta}$-cyclodextrin was found to have the best efficiency and formation of the inclusion complex was saturated when prodigiosin and ${\beta}$-cyclodextrin were mixed in a ratio of 1:8 and shaken at $25^{\circ}C$ and pH 8.0 for 6 h. The maximum algicidal activity against Chattonella antiqua using the inclusion complex stored at $4^{\circ}C$ for 5 weeks of culture was obtained, $52.28{\pm}3.41%$, which was about 5.0 fold higher than that of control. Our results suggest that inclusion complexes of prodigiosin and ${\beta}$-cyclodextrin could serve as effective algicidal agents.

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2061-2064
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• 2005

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.97-101
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• 1996

In this paper, We have studied internal quality incluiding chemical compositions, microscopic structrue and nonmetalic inclusion of test materials. We have analyzed dynamic characteristics of cutting resistence including tensile strength value, hardeness value, impact value etcs. We have compared chip treatments of test materials. In analyzing internal quality, all of test materials have typical ferrite+pearlite structure. But, nonmetallic inclusion have oxide and sulfide inclusion in medium carbon steels, mainly sulfide inclusion is existed in S-free cutting steels. In Ca+S-free cutting steels, calcium aluminate and sulfide complex inclusion, had low-melting points, as deformation of sulfide and oxide inclusion is existed. machining characteristics, cutting resistence is maximum in Ca+S-free cutting steels, minimum in medium carbon steels. Chip treatements are excellent in S-free cutting steels, similar to the Ca+S free cutting steels and medium carbon steels.

• Journal of Pharmaceutical Investigation
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• 제18권4호
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• pp.181-186
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• 1988

Inclusion complex of sulfamethoxazole with ${\beta}-cyclodextrin$ was prepared by freeze-drying method in molar ratios of 1:1, 1:1.25, 1:1.5 and 1:1.75, and the complex formation was identified by ultraviolet and infrared spectroscopies, powder X-ray diffractometry and differential scanning calorimetry. Dissolution rate and solid state stability of the complex were investigated in comparison with those of sulfamethoxazole powder and the physical mixture of sulfamethoxazole with ${\beta}-cyclodextrin$. As a result, the dissolution rate and the stability of solid complexes in various relative humidity conditions increased more remarkably than those of sulfamethoxazole powder and physical mixture. But the difference according to molar ratio of the complex was not recognized.

• Journal of Pharmaceutical Investigation
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• 제27권3호
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• pp.165-171
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• 1997

Ibuprofen, a nonsteroidal antiinflammatory, analgesic and antipyretic drug, has several limitations in clinical application because of low solubility in water and gastrointestinal irritation. Effect of ibuprofen/$2-Hydroxypropyl-{\beta}-cyclodextrin\;(HP{\beta}CD)$ inclusion compound on release of suppository was investigated. Complex formation was confirmed by $^{1}H-\;and\;^{13}C-NMR$ spectroscopy. The release of ibuprofen from suppository base in vitro was significantly increased by the complexation with $HP{\beta}CD$. The release of ibuprofen from hydrophilic base was faster than that from hydrophobic base. In vivo studies, the release rate of ibuprofen from suppository was accelerated after rectal administration in complex form. This results suggested that ibuprofen/$HP{\beta}CD$ complex can be practically used for suppository to have faster effect of ibuprofen with reduced side effect.

• 대한기계학회논문집
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• 제12권3호
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• pp.497-504
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• 1988

본 연구에서는 트랙션이 없는 커스프 균열에 적용한 방법을 확장하여 무한대 에서 균일열유동을 받는 무한체내에 하이포사이클로이드형(hypocycloid type), 대칭이 기형(symmetric airfoil type), 대칭입술형(symmetric lip type) 강체 함유물이 존재 하고 그 표면은 단열되거나 상대온도가 영으로 주어지는 경우에 대해서 열응력세기계 수(thermal stress intensity factor이하에서 TSIF로 표기함)를 유도하고자 한다.