• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4468-4472
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• 2010

SiOC films made by the inductively coupled plasma chemical vapor deposition were researched the relationship between the dielectric constant and the chemical shift. SiOC film obtained by plasma method had the main Si-O-C bond with the molecule vibration mode in the range of $930{\sim}1230\;cm^{-1}$ which consists of C-O and Si-O bonds related to the cross link formation according to the dissociation and recombination. The C-O bond originated from the elongation effect by the neighboring highly electron negative oxygen atoms at terminal C-H bond in Si-$CH_3$ of $1270cm^{-1}$. However, the Si-O bond was formed from the second ionic sites recombined after the dissociation of Si-$CH_3$ of $1270cm^{-1}$. The increase of the Si-O bond induced the redshift as the shift of peak in FTIR spectra because of the increase of right shoulder in main bond. These results mean that SiOC films become more stable and stronger than SiOC film with dominant C-O bond. So it was researched that the roughness was also decreased due to the high degree of amorphous structure at SiOC film with the redshift after annealing.

• 한국석유지질학회:학술대회논문집
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• spring
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• pp.56-65
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• 1998

Methane hydrate is ice-like solid compound consisting of mainly methane and water, and is stable under specific low temperature and high pressure conditions (HSZ : methane hydrate stability zone) that occurs in permafrost regions and in the ocean floor sediments. Geophysical survey was implemented in the southern area of the East Sea, and the HSZ of the study area is determined by the temperature, pressure and local heat flow obtained from the survey and well data. In the study area, methane hydrates could exist in the sediments below the water depths of about $300{\cal}m$, and the base of HSZ is about 600m beneath the seafloor. The acoustically blanking zones in the sediment and phenomena of gas seepage were detected from the seismic section. These sediments have the sufficient physical condition for the formation of methane hydrate. The temperature and pressure conditions were experimentally measured for the dissociation of methane and propane hydrates in Pure water. Equilibrium conditions of methane and propane hydrates were obtained in the pressure range up to 19050Kpa and 401.3Kpa. Under same temperature condition, propane hydrate was dissociated at lower pressure than that of methane hydrate.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.716-719
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• 2009

HFC-134a 의 농도별(99.9%, 80%, 50%, $N_2$ balance)로 하이드레이트의 결정생성/해리 특성을 연구하였다. HFC-134a 하이드레이트는 기/액 경계면에서만 수지상 형태의 하이드레이트 결정이 생성되었으며 수용액 내의 하이드레이트 결정관찰을 위해 물리적인 방법을 이용하였다. HFC-134a 농도가 낮을수록 하이드레이트 결정생성 속도가 둔화되었으며 특히 $N_2$의 함량이 50% 이상일 경우 $N_2$가 확연히 inhibitor 역할을 하였다. 하이드레이트 해리 시에는 기/액 경계면과 수용액 내부에서 매우 다른 양상이 관찰되었으며 하이드레이트 결정이 분해되면서 동공 속에 포집되었던 가스가 방출되는 것을 확인하였다.

• Journal of the Korean Applied Science and Technology
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• v.19 no.3
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• pp.206-212
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• 2002

The catalytic activities of several metalloporphyrin, wherein the porphyrins are TPP(5,lO,l5,20-Tetraphenyl-21H,23H-porphyrin) and (p-X)TPP (X =$CH_{3}O$, $CH_{3}$, F, Cl), are reported for the oxidation of styrene and it's derivatives. The electronic effects of substrates and porphyrins on the catalytic activity of metalloporphyrin containing the transition metal ion such as Mn(III) was discussed. Investigating the correlation between the Michaelis-Menten's rate parameters and the substituent constants, we are going to analyze the influences on the changes of catalytic activity or rate determining step during the processes of the formation and the dissociation of the M-oxo-olefin.

• Macromolecular Research
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• v.15 no.6
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• pp.581-586
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• 2007

Cast DNA/polyethyleneimine (PEI) blend membranes containing different amounts of DNA were prepared using acid-base interaction and characterized with the aim of understanding the polymer electrolyte membrane properties. Two different molecular weights of PEI were used to provide the mechanical strength, while DNA, a polyelectrolyte, was used for the proton transport channel. Proton conductivity was observed for the DNA/PEI membrane and reached approximately $3.0{\times}10^{-3}S/cm$ for a DNA loading of 16 wt% at $80^{\circ}C$. The proton transport phenomena of the DNA/PEI complexes were investigated in terms of the complexation energy using the density functional theory method. In the case of DNA/PEI, a cisoid-type complex was more favorable for both the formation of the complex and the dissociation of hydrogen from the phosphate. Since the main requirement for proton transport in the polymer matrix is to dissociate the hydrogen from its ionic sites, this suggests the significant role played by the basicity of the matrix.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.163.2-163.2
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• 2014

We report catalytic decomposition of few-layer graphene on an $Au/SiO_x/Si$ surface wherein oxygen is supplied by dissociation of the native $SiO_x$ layer at a relatively low temperature of $400^{\circ}C$. The detailed chemical evolution of the graphene covered $SiO_x/Si$ surface with and without gold during the catalytic process is investigated using a spatially resolved photoelectron emission method. The oxygen atoms from the native $SiO_x$ layer activate the gold-mediated catalytic decomposition of the entire graphene layer, resulting in the formation of direct contact between the Au and the Si substrate. The notably low contact resistivity found in this system suggests that the catalytic depletion of a $SiO_x$ layer could realize a new way to micromanufacture high-quality electrical contact.

• Journal of the Korean Ceramic Society
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• v.15 no.1
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• pp.3-8
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• 1978

Effects on the sintering of zircon by minor additives such as $Al_2O_3$, MgO and CaO were studied at $1450^{\circ}C$~$1550^{\circ}C$ for 30 minutes. Shrinkage, compressive strength, bulk density and apparent porosity of sintered specimens were measured in relation to content of minor additives and temperature. Mineral constitutions of the sintered specimens were idenified with X-ray diffractometer. And microstructures of the sintered specimens were observed by scanning electron microscope. The results obtained were as follow. 1) Effect ofthe minor additives such as Al2O3, MgO and CaO on the sintering of zircon was related to reaction between added oxide and silica by dissociation of zircon. 2) Zircon did not dissociate at $1550^{\circ}C$, but it did slightly on the specimen added by Al2O3 5 wt% at $1550^{\circ}C$. 3) Sintering of zircon was promoted by the addition of MgO, $(Al_2O_3＋CaO)$ and (MgO＋CaO), then, this phenomenon was due to the formation of liquid phase.

• Macromolecular Research
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• v.15 no.7
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• pp.671-675
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• 2007

Soybean proteins appear to harbor a great deal of potential as functional ingredients due to the fact that they are composed of highly bioavailable peptides and amino acids. To develop drink- or gel-type foods formulated with soybean protein, the physicochemical properties of intact and chemically modified soy glycinin were assessed. Maleylation to soy glycinin altered the surface charges of glycinin via the modification of lysine residues, and subsequently generated the dissociation of glycinin subunits owing to the increase in charge repulsion. This modification thus improved the solubility of glycinin, particularly under acidic pH conditions. It is worthy of note that maleylation increased the susceptibility of the basic subunits of mTGase and the formation of a substantial quantity of molecules at a low protein solution concentration. The results of dynamic rheological studies indicated that the 5% intact glycinin progressively formed the gel with mTGase treatment in a concentration-dependent manner, but maleylated-glycinin did not.

• Environmental Analysis Health and Toxicology
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• v.12 no.3_4
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• pp.75-84
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• 1997

Chromatographic retention behavior and separation of various phenol derivatives on a Partisil 10 ODS 3 column-with mobile phase containing $\alpha$-cyclodextrin-were systematically studied. The decrease in k' values caused by the addition of cyclodextrins in the mobile phase was based on the formation of an inclusion complex, resulting in weakening of the hydrophobic interaction between solutes and the stationary phase. The content of the organic solvent in the mobile phase also influenced k' values of the solutes, and k' values increased with a decrease of the content of organic solvent in the mobile phase. A simple equation has been derived that reveals the hyperbolic dependence of the capacity factor on the total concentration of cyclodextrin. A plot of the reciprocal of the capacity factor against (CD)$_T$ gives a straight line and the dissociation constant, K$_D$, of the inclusion complex can be calculated from the slope. The capacity factor decreased with increasing temperature. The enthalpy was calculated from the slope of van't Hoff plots. Under optimum conditions, some mixtures of phenol derivatives were able to separated successfully.

• KSBB Journal
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• v.5 no.2
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• pp.125-131
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• 1990

Microbial production of L-phenylalanine using Corynebacterium glutamicum ATCC 21674, a tyrosine auxotroph resistant to aromatic amino acid analogues, has been studied and kinetic analysis was performed. Even though the strain was reported as a tyrosine auxotroph, it produced tyrosine and was able to grow on the minimal medium where no tyrosine was present. The average specific growth rate at the exponential growth phase was 0.087 hr-1. There was a dissociation of growth from the formation of the product. Linear correlation between biomass production and total CO2 production was obtained. The relationship between CO2 evolution rate and sugar consumption rate was also found to be linear.