• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.3
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• pp.234-239
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• 2007

This paper describes the TiW ohmic contact characteristics under the surface treatment of the polycrystalline 3C-SiC thin film grown on $SiO_2/Si(100)$ wafers by APCVD. The poly 3C-SiC surface was polished by using CMP(chemical mechanical polishing) process and then oxidized by wet-oxidation process, and finally removed SiC oxide layers. A TiW thin film as a metalization process was deposited on the surface treated poly 3C-SiC layer and was annealed through a RTA(rapid thermal annealing) process. TiW/poly 3C-SiC was investigated to get mechanical, physical, and electrical characteristics using SEM, XRD, XPS, AFM, optical microscope, I-V characteristic, and four-point probe, respectively. Contact resistivity of the surface treated 3C-SiC was measured as the lowest $1.2{\times}10^{-5}{\Omega}cm^2$ at $900^{\circ}C$ for 45 sec. Therefore, the surface treatments of poly 3C-SiC are necessary to get better contact resistance for extreme environment MEMS applications.

• Journal of Marine Life Science
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• v.3 no.2
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• pp.45-50
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• 2018

Rock bream iridovirus (RBIV) is a megalocytivirus widely infected in various fish species in Korea, causing symptoms of acute inflammation and enlargement of spleen. In our previous study, RBIV induced the initial upregulation but later down-regulation of proinflammatory cytokines and IFN1 gene expression. Signal transducers and activators of transcriptions (STAT) are transcription factors involved in the regulation of immune genes including IFNs. This study was conducted to analyse the expression of STAT2. The expressional study of STAT2 gene was performed in head kidney and spleen upon RBIV infection and immune stimulants like LPS or poly I:C in vitro. Consequently, STAT2 gene expression pattern was different in head kidney and spleen as it was significantly up-regulated by LPS from 4 h to 8 h but down-regulated at 24 h while up-regulated by poly I:C at 8 h in head kidney while, in spleen, STAT2 gene expression was down regulated by LPS but significantly up-regulated by poly I:C. Upon RBIV stimulation, STAT2 gene expression was significantly down-regulated by high dose RBIV at 4 h but up-regulated at 8 h and 24 h in head kidney. In spleen cells, it was up-regulated by medium dose RBIV at 4 h and by high dose RBIV at 4 h and 8 h but down regulated later then. In vivo, STAT2 gene expression was not significantly affected by RBIV infection while significant up-regulated by vaccination at day 7 post-vaccination, indicating STAT2 gene can be involved in adaptive immune response in rock bream.

• Polymer(Korea)
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• v.24 no.5
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• pp.646-655
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• 2000

Polymerizations of higher $\alpha$-olefins were carried out in toluene by using highly isospecific catalyst, rac-(EBI)M(NMe$_2$)$_2$ (EBI=1,2-ethylenebis-(1-indenyl); M=Zr(rac-1); M=Hf(rac-2)) In the presence of Al(i-Bu)$_3$/[Ph$_3$C][B($C_{6}F_{5}$)$_4$]. The polymerization of high $\alpha$-olefin showed high activity and similar polymerization behavior. The polymerization activity was affected by both monomer size and lateral size of polymer chain. The conversion of monomer to polymer decreases with the increased lateral size in the order of 1-pentene>1-hexene>1-octene>1-decene. The same dependences of melting behavior and intrinsic viscosity of polyolefin on lateral size were observed according to the results obtained by differential scanning calorimetry and intrinsic viscosity. All poly($\alpha$-olefin)s showed very high isotacticity (triad) and the isotacticity increases in the order of poly(1-pentene)$^1H$ NMR and Raman spectra analysis showed that chain transfer to cocatalyst, which generates saturated methyl groups, Is a main chain termination. The $\beta$-hydride eliminations, which generate unsaturated vinylidene, tri-substituted, and vinylene end group. are found to be minor chain terminations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.236-236
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• 2009

This paper describes the fabrication and characteristics of Schottky micro hydrogen sensors for high temperatures by using polycrystalline(poly) 3C - SiC thin film grown on Si substrates with thermal oxide layer using APCVD. Pd/poiy 3C-SiC Schottky diodes were made and evaluated by I-V and C-V measurements. Electric current density and barrier height voltage were $2\times10^{-3}\;A/cm^2$ and 0.58 eV, respectively. These devices could operate stably at about $400^{\circ}C$. According to $H_2$ concentrations, their barrier height($\Phi_{Bn}$) were changed 0.587 eV, 0.579 eV, 0.572 eV and 0.569 eV, respectively. the current was increased. Characteristics of implemented sensors have been investigated in terms of sensitivity, linearity of response, response rate and response time. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature chemical sensor applications.

• Textile Coloration and Finishing
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• v.5 no.3
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• pp.182-187
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• 1993

The binding isotherms of Methylene Blue with Poly(vinyl pyrrolidone) (PVP) were determined in a Mcllvaine buffer of pH 8.0 at 3$0^{\circ}C$ by a dynamic dialysis methods. The isotherms showed a partition binding which was increase linearly with the increase of free dye concentration in solution. The Scatchard plots for Poly(vinyl pyrrolidone)-Methylene Blue gave a constant value. The results were interpreted by the McGhee and von Hippel theory considering non-cooperative binding. The intrinsic binding constant k, for Poly(vinyl pyrrolidone)-Methylene Blue was 6.02$\ell$/base mol.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.64-67
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• 2003

Poly(trimethylene terephthalate)(이하 PTT)는 1941년 Caligo Printing Ink사의 Whinfield와 Dickson에 의해 중합 방법이 보고[1]된 이후 상업화를 위한 많은 학문적 연구가 이어져왔다. 그럼에도 불구하고 아직 PET에 비하여 기초 연구가 미비하며 상업적으로 사용하기에는 많은 불안정한 요소들을 가지고 있다. 앞선 연구자들이 밝힌바와 같이 PTT의 결정구조는 2개의 단량체가 1개의 unit cell을 이루면서 결정격자 내에서 O-C $H_2$-C $H_2$-C $H_2$-O가 trans-gauche-gauche-trans형의 coiled spring처럼 형성되어 좋은 elastic recovery와 뛰어난 신축성, 염색성 등 우수한 물성을 가지며 전반적인 성질은 PET와 Nylon의 중간성질을 뛰고 있지만 [2,3] 유리전이온도 (Tg : dir 4$0^{\circ}C$)와 냉결정화오도 ( $T_{ c cold}$ : dir 55$^{\circ}C$)사이의 차이가 15$^{\circ}C$ 정도이므로 섬유상에 많은 경시변화가 일으켜 구조적 불안정성을 가지게 한다 [4]. (중략)

• BMB Reports
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• v.52 no.2
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• pp.133-138
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• 2019

Upon viral infection, the 2', 5'-oligoadenylate synthetase (OAS)-ribonuclease L (RNaseL) system works to cleave viral RNA, thereby blocking viral replication. However, it is unclear whether OAS proteins have a role in regulating gene expression. Here, we show that OAS1 and OAS3 act as negative regulators of the expression of chemokines and interferon-responsive genes in human macrophages. Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein-9 nuclease (Cas9) technology was used to engineer human myeloid cell lines in which the OAS1 or OAS3 gene was deleted. Neither OAS1 nor OAS3 was exclusively responsible for the degradation of rRNA in macrophages stimulated with poly(I:C), a synthetic surrogate for viral double-stranded (ds)RNA. An mRNA sequencing analysis revealed that genes related to type I interferon signaling and chemokine activity were increased in $OAS1^{-/-}$ and $OAS3^{-/-}$ macrophages treated with intracellular poly(I:C). Indeed, retinoic-acid-inducible gene (RIG)-I- and interferon-induced helicase C domain-containing protein (IFIH1 or MDA5)-mediated induction of chemokines and interferon-stimulated genes was regulated by OAS3, but Toll-like receptor 3 (TLR3)- and TLR4-mediated induction of those genes was modulated by OAS1 in macrophages. However, stimulation of these cells with type I interferons had no effect on OAS1- or OAS3-mediated chemokine secretion. These data suggest that OAS1 and OAS3 negatively regulate the expression of chemokines and interferon-responsive genes in human macrophages.

• The Korean Journal of Zoology
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• v.39 no.3
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• pp.248-256
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• 1996

The present study was performed to clone and express human poly (ADP-ribose) synthetase (PARS) cDNA in E coli. For these purposes, the CDNA for human poly (ADP-ribose) synthetase, encoding the entire protein, was cloned into pGEM-7Zf(+). The resulting recombinant plasmid pPARS6.1 was restriction enzyme mapped and its identity was confirmed by Southern blot analysis. The pPARS6. 1 contained full-length CDNA of human PARS and the nudeotide sequences were identical with those reported previously. The recombinant protein which migrated as a unique 120 kDa band on 10% SDS-polyacrylamide gels, was identified as PARS by Southwestern blots using nick-translated DNA probes and by activity gels and activity blots using 32 P-NAD as a substrate for poly (ADP-ribose) synthetase (PARS). The signals corresponding to 120 and 98 kDa proteins were obtained following IPTG (0.4 mM) induction of the PARS cDNA cloned into Xba I-digested pGEM-7Zf(+) vector. Nonspecific signals corresponding to 45 and 38 kDa proteins were also shown in both IPTG-induced and noninduced cells. The nonspecific proteins may be products of incomplete translation or proteolytic products of intact PARS.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.138-142
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• 1999

Imide-containing diamine and dicarboxylic acid monomers, N-(4-aminophenyl)-4-aminophthalimide(APAP), N-(4-carboxyphenyl)-4-carboxyphthalimide(CPCP), N,N'-oxydiphenylenebis(4-aminophthalimide)(ODPAP) and N,N'-oxydiphenylenebis(4-carboxyphthalimide)(ODPCP) were prepared. Poly(amide-imide)s were prepared by condensation reaction of the diamine and the dicarboxylic acid monomers. Poly(amide-imide)s were also prepared from the diamine monomers and aromatic acid chlorodes such as terephthaloyl chloride and isophthaloyl chloride. The polymers possess inherent viscosity of 0.18~0.67 dL/g and brittle films were cast from NMP/LiCl solution. The poly(amide-imide)s are easily soluble in NMP/LiCl and also partially soluble in polar aprotic solvents such as DMF, DMSO, NMP and DMAc even at $80^{\circ}C$. DSC traces of polymers showed no glass transition temperature and melting temperature, and TGA traces showed a 10% weight loss at $500^{\circ}C$.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.6
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• pp.229-235
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• 2002

This paper presents the fabrication of polycrystalline thin film transistor(TFT) using sequential lateral solidification(SLS) of amorphous silicon. The fabricated SLS TFT showed high Performance suitable for active matrix liquid crystal display(AMLCD). The SLS process involves (1) a complete melting of selected area via irradiation through a patterned mask, and (2) a precisely controlled pulse translation of the sample with respect to the mask over a distance shorter than the super lateral growth(SLG) distance so that lateral growth extended over a number of iterative steps. The SLS experiment was performed with 550$\AA$ a-Si using 308nm XeCl laser having $2\mu\textrm{m}$ width. Irradiated laser energy density is 310mJ/$\textrm{cm}^2$ and pulse duration time was 25ns. The translation distance was 0.6$\mu$m/pulse, 0.8$\mu$m/pulse respectively. As a result, a directly solidified grain was obtained. Thin film transistors (TFTs) were fabricated on the poly-Si film made by SLS process. The characteristics of fabricated SLS p -type poly-Si TFT device with 2$\mu\textrm{m}$ channel width and 2$\mu\textrm{m}$ channel length showed the mobility of 115.5$\textrm{cm}^2$/V.s, the threshold voltage of -1.78V, subthreshold slope of 0.29V/dec, $I_{off}$ current of 7$\times$10$^{-l4}$A at $V_{DS}$ =-0.1V and $I_{on}$ / $I_{off}$ ratio of 2.4$\times$10$^{7}$ at $V_{DS}$ =-0.1V. As a result, SLS TFT showed superior characteristics to conventional poly-Si TFTs with identical geometry.y.y.y.