• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.6
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• pp.828-835
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• 2014

GC-TSQ CI technique was applied for analysis of samples for the $32^{nd}$ OPCW proficiency test. Eight chemical weapon convention(CWC) related chemicals were identified by product ion mode analysis with GC-TSQ in the samples. Choice of specific precursor ion made it possible to supply selective total ion chromatograms(TICs) of target molecule. GC-TSQ CI anaylsis technique was useful method for chemical warfare agent verification because analysis selectivity was improved by choice of mother molecule as precursor ion and gave mass spectra.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.109-110
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• 2008

We have performed a density functional theory study to investigate the reaction of the $HfCl_4$ molecule on $H_2O$ terminated Si (001)-$(2\times1)$ surface. The reaction of the $HfCl_4$ molecule is more favorable on OH-terminated site than H-terminated site. The first $HfCl_4$ molecule is adsorbed on a OH-terminated site with 0.21 eV energy benefit. The second $HfCl_4$ molecule is adsorbed on the most adjacent OH-terminated site of the first molecule and the energy benefit is 0.28 eV. The third and forth molecules have same tendency with the first and second ones. The adsorption energies of the fifth and sixth $HfCl_4$ molecules are 0.01 eV, -0.06 eV respectively. Therefore, we find that the saturation Hf coverage is approximately 5/8 of the available hydroxyl site, which is $2.08\times10^{14}/cm^2$. Our model is well matched with an experimental study by reference.

• Macromolecular Research
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• v.12 no.6
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• pp.615-617
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• 2004

We have developed an efficient method for the generation of patterned fluorescence images using a protected precursor molecule. The t-Boc-protecting group of a coumarin derivative was readily removed from a polymer film upon irradiation with UV light in the presence of a photoacid generator to provide the original properties of the coumarin. Fine fluorescence patterns were obtained when using this photolithographic method.

• Journal of Microbiology and Biotechnology
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• v.21 no.8
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• pp.858-860
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• 2011

Production of biosurfactant can be substantially increased by the addition of precursors like vegetable oils, petroleum products, and other water-insoluble substances. Pseudomonas Ptm+ strain produces biosurfactant in the presence of hexachlorocyclohexane (HCH), which specifically emulsifies HCH, a recalcitrant organochlorine pesticide. Addition of previously produced crude biosurfactant by the same organism as a precursor instead of HCH increased production of biosurfactants with a decrease in the total fermentation time from 32 to 24 h. The main objective of this paper was to find alternatives for HCH as an inducer.

• Journal of Plant Biology
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• v.32 no.1
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• pp.51-65
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• 1989

Glycinin is the major storage protein in soybean. It has been known that a molecule of glycinin is composed of 6 subunits, each of which consists of two different kinds of polypeptides, acidic (A) and basic (B) one (NW 39K and 19K, respectively). To study the molecular origin and the relationship of glycinin subunit polypeptides, antibodies against A-and B-polypeptide were obtained by immunizing rabbits with either of the antigens purified by gel filtration and preparative electrophoresis. Each antibody was not only specific for its own antigen polypeptide in soybeans but also recoginzed the precursor which was synthesized in vivo and in vitro. The polyadenylated mRNAs were isolated from immature seeds and leaves and were translated in vitro using wheat germ extract. One of the seed-specific translation products. MW 60K, was identified to be the precursor of glycinin subunit by immunoprecipitation with antibodies against glycinin A- and B-polypeptide. Mature A- and B-polypeptides were not detected in the translte in vitro. These results suggest that the precursor polypeptide is synthesized from the mRNA and is cleaved to yield A- and B-polypeptides which from a glycinin subunit in the cell. Glycinin genes were expressed with the maturation of soybean seeds in a tissue-specific and developmental stage-specific manner.

• Korean Journal of Materials Research
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• v.20 no.11
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• pp.600-605
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• 2010

In order to meet the requirements of faster speed and higher packing density for devices in the field of semiconductor manufacturing, the development of Cu/Low k device material is explored for use in multi-layer interconnection. SiOC(-H) thin films containing alkylgroup are considered the most promising among all the other low k candidate materials for Cu interconnection, which materials are intended to replace conventional Al wiring. Their promising character is due to their thermal and mechanical properties, which are superior to those of organic materials such as porous $SiO_2$, SiOF, polyimides, and poly (arylene ether). SiOC(-H) thin films containing alkylgroup are generally prepared by PECVD method using trimethoxysilane as precursor. Nano voids in the film originating from the sterichindrance of alkylgroup lower the dielectric constant of the film. In this study, methyltriphenylsilane containing bulky substitute was prepared and characterized by using NMR, single-crystal X-ray, GC-MS, GPC, FT-IR and TGA analyses. Solid-state NMR is utilized to investigate the insoluble samples and the chemical shift of $^{29}Si$. X-ray single crystal results confirm that methyltriphenylsilane is composed of one Si molecule, three phenyl rings and one methyl molecule. When methyltriphenylsilane decomposes, it produces radicals such as phenyl, diphenyl, phenylsilane, diphenylsilane, triphenylsilane, etc. From the analytical data, methyltriphenylsilane was found to be very efficient as a CVD or PECVD precursor.

• BMB Reports
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• v.49 no.6
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• pp.337-343
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• 2016

Understanding of trafficking, processing, and degradation mechanisms of amyloid precursor protein (APP) is important because APP can be processed to produce β-amyloid (Aβ), a key pathogenic molecule in Alzheimer's disease (AD). Here, we found that APP contains KFERQ motif at its C-terminus, a consensus sequence for chaperone-mediated autophagy (CMA) or microautophagy which are another types of autophagy for degradation of pathogenic molecules in neurodegenerative diseases. Deletion of KFERQ in APP increased C-terminal fragments (CTFs) and secreted N-terminal fragments of APP and kept it away from lysosomes. KFERQ deletion did not abolish the interaction of APP or its cleaved products with heat shock cognate protein 70 (Hsc70), a protein necessary for CMA or microautophagy. These findings suggest that KFERQ motif is important for normal processing and degradation of APP to preclude the accumulation of APP-CTFs although it may not be important for CMA or microautophagy.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.111-111
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• 1999

반도체 소자의 고집적화 및 고속화에 따라 다층 금속배선에서의 RC 지연이 전체 지연의 주된 요소로 되고 있다. 이런 RC 진연을 줄이기 위해서 현재 다층 금속배선의 층간 절연막으로 사용하고 있는 SiO2 박막(k~3.9)을 보다 낮은 유전상수(low-k)를 가지는 물질로 대체할 것이 요구된다. 층간 절연막으로서 가져야 할 가장 중요한 것은 낮은 유전상수와 높은 열적안정성($\geq$45$0^{\circ}C$)이다. 본 연구에서는 Toluene을 precursor로 사용한 PECVD방법으로 low-k 유사중합체 유기박막을 성장시켰으며 부동한 온도에서 성장된 박막의 특성을 비교하여 증착온도가 박막의 특성에 미치는 영향에 대하여 조사하였다. 유사중합체 유기박막은 platinum(Pt)기판과 silicon 기판위에 같이 증착되었다. Precursor는 4$0^{\circ}C$로 유지된 bubbler에 담겨지고 증발된 precursor molecules는 Argon(Ar:99.999%) carrier 가스에 의해 process reactor 내부로 유입된다. Plasma는 RF(13.56MHz generator로 연결된 susceptor 주위에 발생시켰다. Silicon 기판위에 증착한 시편으로 Fourier transform infrared (FTIR) spectra 및 열적 안정성을 측정하였고, Pt 기판위에 증착한 시편으로 Al/유기박막/Pt 구조의 capacitor를 만들어 열적안정성을 측정하였고, Pt 기판위에 증착한 시편으로는 Al/유기박막/Pt 구조의 capacitor를 만들어 K값 및 절연성을 측정하였다. Capacitance는 1MHz 주파수에서 측정하였다. 열적안정성은 30분동안 Ar 분위기에서 annealing하기 전후의 증착막의 두께의 변화를 측정함으로써 조사하였으며 유기박막의 두께는 surface profilometer로 측정하였다. 증착온도가 45$^{\circ}C$에서 15$0^{\circ}C$, 25$0^{\circ}C$로 높아짐에 따라 k값은 높아졌지만 대신 열적안정성은 좋아졌다. plasma power 30W인 경우 45$^{\circ}C$에서 증착했을 때 유전상수는 2.80으로 낮았지만 40$0^{\circ}C$에서 30분 동안 열처리한 후 두께가 49% 감소하였다. 그러나 25$0^{\circ}C$에서 증착했을 때 유전상수는 3.10으로 좀 높아졌지만 열적으로는 40$0^{\circ}C$까지 안정하였으며 45$0^{\circ}C$에서도 두께의 감소는 8%에 불과했다.

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.510-515
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• 2001

It was first time that low frequency R.F. derived plasma enhanced MOCVD with frimethylborate precursor was used to fabricate a new ternary compound $BO_{x}$ $N_{y}$ . The formation of BON molecule was resulted from nitrogen nitrifying B-O, and forming the angular molecule structure proved by XPS and FT-IR results. The relationship between hardness and film thickness was studied. An thickness-independent hardness was fond about 10 GPa. The empirical calculation of band-gap and UV test result showed that our deposited $BO_{x}$ $N_{y}$ thin film was semiconductor material with 3.4eV of wide band gap. The electrical conductivity, $4.8$\times$10^{-2}$ /($\Omega$.cm)$^{-1}$ also confirmed that $BO_{x}$ $N_{y}$ has a semiconductor property. The roughness detected from the as-grown films showed that there was no serious bombarding effect due to anion in the plasma occurring in the RF frequency derived plasma.

• Korean Journal of Materials Research
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• v.13 no.5
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• pp.328-332
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• 2003

Characteristics of $TiO_2$nanoparticles controlled by precursor flow rate and reaction temperature in chemical vapor condensation process were interpreted in the view of decisive reaction factors, i.e. supersaturation ratio, concentration of vapor molecule, collision frequency and rate, and residence time, which directly affect the particle size and size distribution in CVC reactor. As results, the increases of precursor flow rate and reaction temperature induced the increase in the average sizes of $TiO_2$ nanoparticles in CVC reactor by acceleration of coagulation growth due to the increase of collision between $TiO_2$vapor molecules and particles. The effects of reaction factors on the characteristics of$TiO_2$nanoparticles were discussed with considering particle formation process in CVC reactor under given process parameters.