• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.2063-2069
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• 2011

We studied the interaction of 3,3',3'',3'''-ethylenetetrakis-4-hydroxycoumarin (EHC) with bovine serum albumin (BSA) in acetate buffer and phosphate buffer with different pH values by UV-vis absorption spectrometry and fluorescence spectrometry respectively. It was found that the pH values of the buffer solutions had an effect on the interaction process. In acetate buffer of pH 4.70, the carbonyl groups in EHC bound to the amino groups in BSA by means of hydrogen bond and van der Waals force, which made the extent of peptide chain in BSA changed. By contrast, in phosphate buffer of pH 7.40, hydrophobic force played a major role in the interaction between EHC and BSA, while the hydrogen bond and van der Waals force were also involved in the interaction. The results of spectrometry indicated that BSA could enhance the fluorescence intensity of EHC by forming a 1:1 EHC-BSA fluorescent complex through static mechanism at pH 4.70 and 7.40 respectively. Furthermore, EHC bound on site 1 in BSA.

• Korean Chemical Engineering Research
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• 제48권2호
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• pp.224-231
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• 2010

최근 발표된 GvdW(Generalized van der Waals) EOS에서는 상호작용이 vdWf(van der Waals force)뿐이라고 여겨지는 구체특성의 비선형적 입자에 대해 임계영역에서의 상태 특성이 잘 기술될 수 있음을 보였다. 그러나 기존의 논문에서는 선형성을 갖는 입자의 형태나 정전기적 인력 등 추가적인 상호작용이 존재하는 입자에 대해서도 GvdW가 정확성을 나타내는지에 대한 분석이 이루어지지 않아, GvdW의 범용성에 대한 논란의 여지가 남아있다. 따라서 본 논문에서는 선형성을 갖는 입자인 포화 알칸 유도체 류(R=methane, ethane, propane, butane)와 정전기적 인력이 극한적으로 나타나는 포화 아민 유도체 류($RNH_2$, R=methyl-, ethyl-, propyl-amine)에 대한 임계영역 시뮬레이션을 위하여 이들 입자들에 대한 GvdW의 파라미터 값을 정의하였으며, 이를 바탕으로 최근에 발표된 기존의 상태방정식들과 비교 분석하였다. 시뮬레이션 결과 포화 알칸 유도체 류와 포화 아민 유도체 류 입자에 대하여 GvdW는 기존의 방정식들보다 측정값에 더 가까운 정확한 임계영역 특성이 나타남을 확인할 수 있었다. 특히 분자량이 큰 부탄에 있어서는 GvdW EOS만이 임계점에 정확하게 근접함을 알 수 있었다.

• 대한화학회지
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• 제22권2호
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• pp.86-94
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• 1978

Theophylline 鹽酸鹽의 結晶 및 分子 構造를 3次元的인 X-線 回折 data로부터 Patterson法에 의하여 決定하였고, Block-diagonal least square와 Fourier法으로서座標를 精密化하였다. 이化合物은 a = 14.01, b = 11.49, c = 6.77${\AA}$의 單位格子를 가지는 斜方晶系에 屬하는 結晶 이며 空間群은 $P_{na21}$ 이다. 743개의 觀測된 data에 대한 최종 R값은 12.2%이다. Theophylline 分子內 原子間 距離는 유사化合物에서 얻은 값과 거의 일치한다. 이들 原子는 同一平面을 이루고 있으며 HCl의 鹽素原子는 theophylline의 N(1) 原子와 3.06${\AA}$ 距離의 Cl${\cdot}{\cdot}{\cdot}$N(1), 水素結合을 이루고 있다. 모든 分子 는 대략 (001)과 (002)面上에 배열되어 있고 各分子間은 van derWaals force에 의해 三次元的 構造를 이루고 있다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2006년도 춘계학술발표대회 및 제10회 신소재 심포지엄 논문개요집
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• pp.20.1-20.1
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• 2006

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2002년도 춘계 기술심포지움 논문집
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• pp.193-197
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• 2002

The tribological properties and van der Waals attractive forces and the thermal stability of films are very important characteristics of highly hydrophobic fluorocarbon (FC) films for the long-term reliability of nano system. The effect of thermal annealing on films and van der Waals attractive forces and friction coefficient of films have been investigate d in this study. It was coated Al wafer which was treated O2 and Ar that ocatfluorocyclobutane ($C_4_{8}$) and Ar were supplied to the CVD chamber in the ratio of 2:3 for deposition of FC Films. Static contact angle and dynamic contact angle were used to characterize FC films. Thickness of films was measured by variable angle spectroscopy ellipsometer (VASE). Nanotribological data was got by atomic force microscopy (AFM) to measure roughness, lateral force microscopy (LFM) to measure friction force, and force vs. distance (FD) curve to evaluate adhesion force. FC films were cured in N2 and vacuum. The film showed the slight changes in its properties after 3 hr annealing. FTIR ATR studies showed the decrease of C-F peak intensity in the spectra as the annealing time increased. A significant decrease of film thickness has been observed. The friction force of Al surface was at least thirty times higher than ones with FC films. The adhesive force of bare Al was greater than 100 nN. After deposit FC films adhesive force was decreased to 40 nN. The adhesive force of films was decreased down to 10 nN after 24 hr annealing. During 24 hr annealing in $N_2$and vacuum at $100^{\circ}C$ film properties were not changed so much.

• 대한화학회지
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• 제21권5호
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• pp.320-329
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• 1977

p-Phenylenediamine dihydroperchlorate의 세포상수는 $a=4.79{\pm}0.02,\;b=9.03{\pm}0.02,\;c=7.12{\pm}0.03{\AA},\;{\alpha}=109.4{\pm}0.2,\;{\beta}=79.6{\pm}0.2,\;r=104.6{\pm}0.2^{\circ},\;Z=1$이며 공간군은 $P\={1}$이다. 구조는 Patterson 및 Fourier법으로 해석하였으며 block diagonal 최소자승법으로 정밀화하였따. 등경사 Weissenberg 사진들에서 얻은 387개의 관측된 반사에 대하여 R값은 0.13이었다. 이 물질의 결정구조에서 수소결합은 아미노기와 과염소산 이온 사이에서 이루어져 있으며 2가지 형이 있다. 첫째것은, 한개의 삼지형 N${\cdot}{\cdot}{\cdot}$O 수소결합이고, 둘째것은, 보통형의 2개의 N${\cdot}{\cdot}{\cdot}$O 수소 결합이다. 한개의 p-phenylenediamine 그룹은 실험오차 내에서 평면이며 12개의 과염소산이온에 결합되어 있다. 그중 10개의 과염소산이온은 수소결합으로 연결되어 있으며 2개는 van der Waals 힘들로 접촉되어 있다. 한개의 과염소산이온은 6개의 p-phenylenediamine과 4개의 과염소산이온에 의하여 둘러싸여 있따. 6개의 p-phenylenediamine 그룹 중 5개는 수소결합이 되어있고 나머지는 van der Waals 힘으로 접촉되어 있다.

• Nuclear Engineering and Technology
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• 제47권6호
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• pp.662-668
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• 2015

A suspension of titanium nanoparticles (Ti NPs) in liquid sodium (Na) has been proposed as a method to mitigate the violent sodium-water reaction (SWR). The interparticle potential between Ti NPs in liquid Na may play a significant role in the agglomeration of NPs on the reaction surface and in the bulk liquid Na, since the potential contributes to a reduction in the long-term dispersion stability. For the effective control of the SWR with NPs, a physical understanding of the molecular dynamics of NPs in liquid Na is key. Therefore in this study, the nonretarded Van der Waals model and the solvation potential model are employed to analyze the interparticle potential. The ab initio calculation reveals that a strong repulsive force driven by the solvation potential exceeds the interparticle attraction and predicts the agglomeration energy required for two 10-nm Ti NPs to be $4{\times}10^{-17}J$. The collision theory suggests that Ti NPs can be effective suppressors of the SWR due to the high energy barrier that prevents significant agglomeration of Ti NPs in quiescent liquid Na.

• 반도체디스플레이기술학회지
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• 제6권4호
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• pp.1-4
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• 2007

Carbon nanotube oscillators encapsulating copper nanowire were investigated by molecular dynamics simulations. The excess forces due to the carbon-carbon van der Waals interactions are higher than the excess force due to carbon-copper interactions. And the masses of copper atoms are higher than those of carbon atoms. So, the carbon atoms are easier accelerated than the copper atoms. When the encapsulated copper nanowire deforms the encapsulating nanotube, the frequency can not be estimated by the mass-frequency dependence in classical oscillation theory.

• 반도체디스플레이기술학회지
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• 제6권1호
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• pp.27-30
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• 2007

The gigahertz oscillator behavior of double-walled boron-nitride nanotube (BNNT) was investigated by using classical molecular dynamics simulations. The BNNT oscillator characteristics were compared to carbon-nanotube (CNT) and hybrid-C@BNNT oscillators. The results show that the BNNT oscillators are higher than the van der Waals force of the CNT oscillator. Since the frictional effects of BNNT oscillators are higher than that of a CNT oscillator, the damping factors of BNNT and hybrid oscillators are higher than that of a CNT oscillator.

• Preventive Nutrition and Food Science
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• 제2권4호
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• pp.316-320
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• 1997

Phenolic acids are regarded as harmful materials in food and environment science but recently, as useful materials, and thus adsorption is recommended as an effective separation technique to recover or remove phenolic acids from diluted solution. If the adsorbed phenolic compounds were useful materials, the materials should be recovered through desorption. Desorption using supercritical carbon dioxide(SC-$CO_2$) was tried to separate food-borne phenolic acids from charcoal in single solute system. In the comparisons of desorption amounts, gallic acid had the lowest lolubiligy to SC-$CO_2$. Gallic acid has more hydroxy functional groups than the other phenolic acids, which was immiscible with nonpolar SC-$CO_2$. Ferulic acid was yielded more than p-coumaric acid, because ferulic acid had much bigger molecular weight, which was affected more by van der Waas force. It was found that the most affecting factor on desorption amounts was the solubility of phenolic acids to SC-$CO_2$. The second affecting factor was van der Waals force. Response surface methodology(RSM) was conducted to read the trend of desorption. Increasing density of SC-$CO_2$ raised solubility of phenolic acids.