• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집
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• pp.29-32
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• 2005

Poly (methyl methacrylate) (PMMA) is one of the promising representive of polymer gate dielectric for its high resistivity and sutible dielectric constant. PMMA (Mw=96700) films were prepared on p-Si by spin coating method. PMMA were coated compactively and flatly as observeed by AFM. MIS(Al/PMMA/p-Si) structure was made and capacitance-voltage (C-V) and current-voltage (I-V) measurements were done with PMMA films for different thermal treatment temperature. PMMA films were showed proper dielectric constant and breakdown voltage. Above the glass transition temperature PMMA films degraded. C-V measured at various frequencies, dielectric constant increased a little. The absence of hysteresis in the C-V characteristics, which eliminate the possibility of mobile charges in the PMMA films. The observed thermal stability, smooth surfaces, dielectric constant, I-V behavior implies PMMA formed by spin coating can be used as an efficient gate dielectric layer in OTFTs.

• 한국응용과학기술학회지
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• 제13권1호
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• pp.41-46
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• 1996

Durable softening water repellents such as PODCWs were prepared by blending cationized compound of poly(octadecyl methacrylate-co-2-diethylaminoethyl methacrylate), of which synthetic methods were reported in the previous paper, activated polythylene, waxes, and emulsifiers. Water repellency of prepared PODCWs was measured by performing water repellent finish to various fabrics, PODCWs showed a good water repellency for P/C blended fabrics and their repelling tendency was in the order of P/C blended fabrics>cotton fabrics>nylon taffeta. The initial water repellencies of PODCW-1 and PODCW-2 were 100 and $100^{-}$ points, respectively, for P/C blended fabrics. And also, PODCW-1 and PODCW-2 were confirmed as durable water repellents with the results of making little difference of water repellency as ${\pm}5$ point after and before washing.

• 약학회지
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• 제31권2호
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• pp.116-125
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• 1987

It is still difficult and time consuming to obtain cDNA sequences that contain the entire nucleotide sequence of the corresponding mRNA. A rapid and high efficient cloning method to obtain full-length cDNA segments is thus developed. The cloning procedure described here consists of the construction of oligo(dT)-tailed vector primer using pWR34 plasmid, polyadenylation of mRNA-cDNA heteroduplex using terminal deoxytransferase, and replacement of MRNA strand with DNA by RNase H and DNA polymerase I. The restriction endonuclease analysis shows that the size of inserted-cDNA is in the range of 1.5~4.0 kb long suggesting that most of cloned cDNA are full-length or nearly full-length cDNA. The plasmid-DNA recombinants obtained were 4$\times$$10^5$~$10^{6}$ per $\mu\textrm{g}$ of rat liver poly (A$^+$)mRNA, which is 4 to 10 fold higher cloning efficiency in comparison to the presently used methods for full-length cDNA cloning. The results indicate that the described cloning system is much simpler, less time consuming, and very efficient cloning method to construct a cDNA library.

• 전기화학회지
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• 제3권1호
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• pp.25-30
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• 2000

다결정 Pt/0.1 M $H_2SO_4$수성 전해질 계면에서 중간주파수 구간의 위상이동 변화와 Langmuir흡착등온식 사이의 관계를 교류임피던스 방법 즉 위상이동 방법을 이용하여 연구 조사하였다. 제안된 계면등가회로는 전해질저항($R_S$), Faraday저항$(R_F)$, 흡착유사용량$(C_\varphi)$의 등가회로 요소($C_P$)의 직렬접속으로 구성된다 지연되는 위상이동$(\varphi)$은 음전위(E) 및 주파수(f)에 따르며, $\varphi=-tan^{-1}[1/2{\pi}f(R_s+R_F)C_p]$이다. 중간주파수(6Hz)에서 위상이동 변화$(\varphi\;vs.\;E)$는 Langmuir흡착등온식$(\theta\;vs.\;E)$의 결정에 적용할 수 있는 실험적인 방법이다. 다결정 $Pt/0.1\;M\;H_2SO_4$ 전해질 계면에서 수소의 흡착평형 상수(K)와 흡착표준자유에너지$({\Delta}G_{ads})$는 각각 $1.8\times10^{-4}$와 21.4kJ/mol이며 과전위 수소흡착(OPD H)에 기인한다.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1996년도 한국생물과학협회 국제학술대회
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• pp.195.2-195
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• 1996

acs gene cloning was constructed by subcloning the 2.2-kb MunI-MunI restriction fragment of 638 and 639 which include acs gene from the kohara phage into the unique EcoRI site of pUC18 and pJM9131 containing the PHA biosynthesis genes. Then recombinant E. coli fadRatoC(Con) mutants containing the polyhydroxyalkanoate(PHA) biosynthesis genes are able to incoporate s significant levels of 3-hydroxyvalerate (3HV) into the copolymer [P(3HB-co-3HV)]. Quantitative determination of PHB and P(3HB-co-3HV) was performed by gas-chromatographic analysis of extracts obtained from methanolysis of lyophilized cells.

• Bulletin of the Korean Chemical Society
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• 제2권4호
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• pp.142-147
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• 1981

A blend polymeric system composed of poly(methyl methacrylate) (PMMA or PM) and polystyrene (PS) dissolved in chloroform was rheologically studied. The viscosities ${\eta}_{bl}$ of the blend system with various blending ratios ${\chi}$ changing from zero (pure PS solution) to unity (pure PMMA solution) were measured at $25{\circ}C$ as a function of shear rates ${\dot{s}}$ by using a Couette type viscometer. ${\eta}_{bl}$ at a given ${\dot{s}}$ decreased exponentially with ${\chi}$ reaching asymptotic constant value of ${\eta}_{bl}$ ; ${\eta}_{bl}$ at a given ${\chi}$ is greater at a smaller ${\dot{s}}$. These results are explained by using Ree-Erying's theory of viscosity, ${\eta}_{bl}=(x_1{\beta}_1/{\alpha}_1)_{b}_1＋ (x_2{\beta}_2/{\alpha}_2)_{bl}[sinh^{-1}{\beta}_2(bl) {\dot{s}}]/{\beta}_2(bl){\dot{s}}$. The Gibbs activation energy ${\Delta}G_i^\neq$(i = 2 for non-Newtonian units) entering into the intrinsic relaxation time ${\beta}$ is represented by a linear combination ${\Delta}G_i^\neq(bl) ={\chi}{\Delta}G_i^{\neq}_{iPM}+(1-{\chi}){\Delta}G_i^{\neq}_{iPS}$;the intrinsic shear modulus$[[\alpha}_i]^{-1}$ is also represented by $[{\alpha}_i(bl)]^{-1}={\chi}[{\alpha}_{iPM}]^{-1}+(1-{\chi})[{\alpha}_{iPS}]^{-1}$ and the fraction of area on a shear surface occupied by the ith flow units $x_i(bl)$ is similarly represented, i.e., $x_i(bl) = {\chi}x_{iPM}+(1-{\chi})x_{iPS}$. By using these ideas the Ree-Eyring equation was rewritten which explained the experimental results satisfactorily.

• Archives of Pharmacal Research
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• 제29권12호
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• pp.1140-1146
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• 2006

Ceramide analogs are potential chemotherapeutic agents. We report that a ceramide analog induces apoptosis in human prostate cancer cells. The ceramide analog induced cell death through an apoptotic mechanism, which was demonstrated by DNA fragmentation, the cleavage of poly ADP ribose polymerase (PARP), and a loss of membrane asymmetry. Treating the cells with ceramide analog resulted in the release of various proapoptotic mitochondrial proteins including cytochrome c and Smac/DIBLO into the cytosol, and a decrease in the mitochondrial membrane potential. In addition, the ceramide analog decreased the phospho-Akt and phospho-Bad levels. The expression of the antiapoptotic Bcl-2 decreased slightly with increasing Bax to Bcl-2 ratio. These results suggest that the ceramide analog induces apoptosis by regulating multiple signaling pathways that involve the mitochondrial pathway.

• Elastomers and Composites
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• 제54권4호
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• pp.286-293
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• 2019

In this study, flexible poly(ethylene-ter-1-hexene-ter-divinylbenzene) was prepared using four types of metallocene catalysts (rac-Et(Ind)₂ZrCl₂, rac-SiMe₂(Ind)₂ZrCl₂, rac-SiMe₂(2-Me-Ind)₂ZrCl₂, (C₅Me₅)TiCl₂[O-2,6-ⁱPr₂(C₆H₃)]) and two types of borate catalysts (trityl tetrakisborate and dimethylanilinium tetrakisborate). The yield, catalytic activity, molecular weight, structure, composition, and thermal properties of the terpolymers prepared using the various catalysts and cocatalyst systems were evaluated. Epoxidation of the terpolymers was successfully performed and this transformation was studied by ¹H NMR and FTIR.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.220-223
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• 1995

Stable polyion-complexed polymeric monolayrers were prepared by spreading perfluoroalkyl monomaleatd copolymers. C$_2$F$\_$8/MA-VE$_2$ and C$_2$F$\_$8/Mv-VE$_3$ on aqueous poly(allylamine) subphase. The monolayer properties have been studied by the surface pressure-area($\pi$-A) isotherms. The C$_2$F$\_$8/MA-VE$_3$containing longer oligoethyleneglycol pendant showed more expaned monolayer phase than the C$_2$F$\_$8/MA-VE$_2$ The polyion-complexed monolayers were transferable on various substrates, and the resulting Langmuir-Blodgett(LB) films were characterized b ET-IR spectroscopy and scanning electron microscopy(SEM) Two-dimensional crosslinking to from a polymer network was achieved by amide formation through heat treatment under vacuum with concurrent removel of perfluoroalkyl tails. SEM observation of this film ona porous membrane filter showed that the four layer film was sufficiently stable to cover the filter pore size of 0.1$\mu\textrm{m}$. The C$_2$F$\_$8/MA-VE$_3$revealed better covering capability than the C$_2$F$\_$8/MA-VE$_2$Immersion of this film in water or in benzend did not cause any change in its appearance and in FT-IR spectra.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1592-1594
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• 2003

This paper presents the deposition and characterization of microcrystalline silicon(${\mu}c$-Si:H) films by HWCVD(Hot-wire Chemical Vapor Deposition) method at low substrate($300^{\circ}C$). The filament temperature, pressure and $SiH_4$ concentration were determined to be a critical parameter for the deposition of poly-Si films. Series A was deposited under the conditions of $1380^{\circ}C$(Tf), 100 mTorr and $2{\sim}10%\{SC:SiH_4/(SiH_4+H_2)\}$ for 60 min. Series B was deposited under the conditions of $1400{\sim}1450^{\circ}(T_f)$, 30 mTorr and $2{\sim}12%$(SC) for 60 min. The physical characteristics were measured by Raman and FTIR spectroscopy, dark and photoconductivity measurements under AM1.5 illumination.