• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.145-146
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• 2015

초미세 가공 및 치수안정성 향상을 위한 다이아몬드 마이크로 블레이드의 DLC 코팅이 연삭 과정에서 결합구조가 안정적으로 유지되는지 알아보기 위해 Cu/Sn 금속 결합재에 $MoS_2$ 고체 윤활제를 첨가한 후 PAPVD법으로 DLC 박막을 블레이드의 측면에 증착하였다. 실착 절삭 시험을 위해 마이크로 블레이드 시편을 제조하여 충분한 드레싱 과정 후 절삭 시험을 행하였으며 라만 분광법을 통해 절삭 전후 DLC 코팅에 존재하는 $sp^2$, $sp^3$ 결합의 분율을 조사하고 그 결과를 토대로 DLC 코팅의 특성의 변화를 분석하였다. DLC 코팅에 존재하는 D밴드와 G밴드의 비인 ID/IG는 절삭 후 증가하는 경향을 보였으며 결과적으로 절삭 과정 중 흑연화가 진행되었음을 확인하였다.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.311.1-311.1
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• 2003

Dose-independent pharmacokinetic parameters of KR-60436, a new proton pump inhibitor, were evaluated after an intravenous, iv (5, 10, and 20 mg/kg) and an oral (20, 50, and 100 mg/kg) administration to rats. The hepatic, gastric, and intestinal first-pass effects were also measured after iv, intraportal (ip), intragastric (ig), and intraduodenal (id) administration at a dose of 20 mg/kg to rats. (omitted)

• Applied Chemistry for Engineering
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• v.32 no.2
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• pp.143-148
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• 2021

A thermally conductive 200 ㎛ thick polyimide-based film was made from a polyamic acid (PAA) precursor containing graphene prepared from graphite rod using an electrostatic discharge method in order to improve the thermal conductivity and expand the applicability of polyimide (PI) film. Properties of graphene produced by electrostatic discharge were measured by Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). As a result of Raman spectrum and XPS analyses of as-prepared graphene, the ID/IG ratio was 0.138 and C/O value was 24.91 which are excellent structural and surface chemical properties. Moreover, thermal conductivities of polyimide films increased exponentially according to graphene contents but when the graphene content exceeded 40%, the polyimide film could not maintain its shape. The thermal conductivity of carbonized PI film made from PAA containing 40 wt% of graphene was 51 W/mK which is greatly enhanced from the pristine carbonized PI film (1.9 W/mK). This result could be originated from superior properties of graphene prepared from the electrostatic discharge method.

• Composites Research
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• v.36 no.3
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• pp.167-172
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• 2023

The manufacturing technology of composite material is applicable with filler characteristics maintaining low cost, flexibility, and easy process to develope the various functional composite materials. To realize functional composites, various researches on the high performance of composite materials using graphene as a filler is being actively conducted. In this study, physical and chemical properties were investigated using graphene to improve high functional properties. Graphene oxide (GO) was prepared using graphane nanoplatelet (GNP), and reduced graphene oxide (R-GO) was formed by reducing GO. The physical properties of GO and R-GO were analyzed, and the reliability of the manufactured method was reviewed by comparing that of GNP results. As a result of analysis by Raman spectroscopy, in the case of R-GO, it was confirmed that the intensity of D-peak and G-peak decreased compared to GO, and an increase of 0.08 was observed through the ratio of ID/IG. For the FTIR results, GO and RGO has a repeating C-C and C=C connection structure unlike GNP. GO and R-GO show clear peaks for C-O bond, C=C bond, C=O bond, and O-H bonding. As a result of X-ray diffraction analysis, GNP showed a wide diffraction peak at 25.86° of (002) plane characteristics, whereas GO and R-GO showed peaks corresponding to (001) and (100) planes. It was also found that the interlayer distance of GO increased by about 2.6 times compared to GNP.

• Toxicological Research
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• v.14 no.2
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• pp.205-209
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• 1998

To evaluate immunotoxicity of skin decontamination kit(SDK) newly-developed in Agency for Defense Development(ADD), delayed contact hypersensitivity (maximization) test and passive cutaneous anaphylaxis(PCA) test of SDK were performed and the results were compared with those of M 291. In maximization test, sensitization reaction was induced by id injection (2.5 mg / 0.1 $\textrm{m}{\ell}$/ guinea pig or 2.5 mg+CFA/0.1 $\textrm{m}{\ell}$/guinea pig) and topical application (2.5 mg/$\textrm{m}{\ell}$/guinea pig) with SDK or M291 at an interval of 1 week, and 2 weeks later, challenged by topical application with 25 mg/$\textrm{m}{\ell}$/guinea pig. SDK and M291 did not induce any reactions, showing 0 point of sensitization score and 0% of sensitization rate. In conclusion, it is suggested that SDK and M291 do not induce delayed contact hypersensitivity. In PCA test, rats were administered id with mouse anti-SDK serum and challenged iv with a mixture of antigen SDK and Evan's blue. SDK did not induce blue spots at the injection sites of both high (2.5 mg/mouse) and low (1.25 mg/mouse) dose-induced antisera. In contrast, BSA, positive control produced spots larger than 5 mm in diameter at the injection sites of BSA-induced antiserum up to $2^2$ ~ $2^4$dilution. In conclusion, it is suggested that SDK do not induce IgE production and is not a PCA-reaction inducer.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1361-1365
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• 2001

Recombinant immunotoxins are hybrid cytotoxic proteins designed to selectively kill cancer cells. A divalent immunotoxins, [B3(FabH1)-PE38]2, was constructed by recombining Fab domain of B3 antibody as a cell-targeting domain and Pseudo monas exotoxin A (PE) as a cytotoxic domain. Monoclonal antibody, B3, is the murine antibody (IgG1k) directed against Lewis Y-related carbohydrate antigens, which are abundant on the surface of many carcinomas. Fab fragment of this antibody was used in this study with the modified hinge sequence where last two cysteines out of three were mutated to serine. PE is a 66 kDa bacterial toxin that kills eukaryotic cells by inhibiting protein synthesis with ADP ribosylation of ribosomal elongation factor 2 (EF2). Fc region of B3 antibody was substituted with the truncated form of PE (38 kDa, PE38) on DNA level. [B3(FabH1)-PE38]2 was formed by disulfide bond between cysteines in the modified hinge region of B3(FabH1)-PE38. Each polypeptide for recombinant immunotoxins was overexpressed in Escherichia coli and collected as inclusion bodies. Each inclusion body was solubilized and refolded, and cytotoxic effects were measured. Divalent immunotoxins, [B3(FabH1)-PE38]2, had ID50 values of about 10 ng/mL on A431 cell lines and about 4 ng/mL on CRL1739 cell lines. Control immunotoxins, B3(scFv)-PE40, had ID50 values of about 28 ng/mL on A431 cell lines and about 41 ng/mL on CRL1739 cell lines. Divalent immunotoxins, [B3(FabH1)-PE38]2, had higher cytotoxic effects than B3(scFv)-PE40 control immunotoxins.

• Clinical and Experimental Pediatrics
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• v.50 no.1
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• pp.28-32
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• 2007

Purpose : Human angiotensin converting enzyme (ACE) gene shows an insertion/deletion polymorphism in 16 intron, and three genotypes are determined by whether a 287 bp fragment of the DNA is present or not; II, ID and DD genotype. DD genotype has been suggested as a risk factor of chronic nephrotic disease such as IgA nephropathy and diabetic nephropathy, various cardiovascular diseases and several other diseases. ACE activity increases in acute hepatitis, chronic persistent hepatitis, chronic active hepatitis and cirrhosis. On the other hand, patients with fatty livers have normal ACE activity. This study was designed to find out the relation between polymorphsims of the ACE genes and neonatal hyperbilirubinemia in Koreans. Methods : The genomic DNA was isolated from 110 full-term Korean neonates who had hyperbilirubinemia with no obvious causes (serum bilirubin$${\geq_-}12mg/dL$$) and 164 neonates of a control population (serum bilirubin <12 mg/dL). We performed polymerase chain reaction (PCR) to see the allele of the ACE gene. Electrophoresis was done in the PCR products in 1.5 percent agarose gel, and then DNA patterns were directly visualized under ethidium bromide staining. Results : ACE genotypes in the hyperbilirubinemia group are as follows; 26.36 percent for II, 53.64 percent for ID, 20.00 percent for DD, 0.532 for I allele and 0.468 for D allele. These distributions were not significantly different from those in the control group; 24.39 percent for II, 51.83 percent for DI, 23.78 percent for DD, 0.503 for I allele and 0.497 for D allele. Conclusion : In this study, ACE gene polymorphism was detected in the neonatal hyperbilirubinemia and control group. The most frequent genotype was ID. Our results indicate that the ACE gene polymorphism is not associated with the prevalence of neonatal hyperbilirubinemia in Koreans.

• Elastomers and Composites
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• v.18 no.4
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• pp.140-147
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• 1983

The purpose of this dissertation is to increase oxidation resistance for Polybutadiene & Polyisoprene, and to investigate the energetics of inhibited oxidation of Polybutadiene & Polyisoprene stabilized with various types of antioxidants using DSC. The results of the study are as fellows: 1. In the DSC SCREEN for the onset temperature of oxidation, Polybutadiene was faster than Polyisoprene for the samples containing no antioxidant in air. 2. In the DSC evaluation for Polybutadiene, Recipe BG-4 with 2.0phr compounds of antioxidant was the best effective, and Recipe BS-4 with 2.0phr compounds of antioxidant was the worst effective, and the degrees of effect of antioxidant were exhibited in the ranking of G-1, D, BHT, and SP, roughly. 3. In the DSC evaluation for the Polyisoprene, Recipe IG-4 with 2.0phr compounds of antioxidant was the best effective, and Recipe ID-4 with 2.0phr compounds of antioxidant was the worst effective, and the degrees of effect of antioxidant were exhibited in the ranking of G-1, SP, BHT, and D roughly. 4. In the study on enthalpy which depends on exothermal reaction, the enthalpy of Polyisoprene was gloater than that of Polybutadiene. However, the problem was not solved completely, and it needs further studies.

• Journal of the Korean institute of surface engineering
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• v.42 no.4
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• pp.173-178
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• 2009

DLC film was synthesized on plastic injection mold(SKD11, $30\;mm\;{\times}\;19\;mm\;{\times}\;0.5\;mm$) and Si(100) wafer for 2 h at $130^{\circ}C$ under 6 mTorr using hybrid method of rf sputtering and ion source. The obtained film was analysed by Raman spectroscopy, AFM, TEM, Nano indenter and scratch tester, etc. The film was defined as an amorphous phase. In the Raman spectrum, broad peak of $sp^2$-bonded carbon attributed to graphite at $1550\;cm^{-1}$ were observed, and the ratio of ID($sp^3$ diamond intensity)/IG($sp^2$ graphite intensity) was approximately 0.54. The adhesion of DLC film was more than 80 N with scratch tester when $0.2\;{\mu}m$ thickness Cr was coated as interlayer. The micro-hardness was distributed at 35~37 GPa. The friction coefficient was 0.02~0.07, and surface roughness(Ra) was 0.34~1.64 nm. The lifetime of DLC coated plastic injection mold using as a connector part in computer was more than 2 times of non-coated mold.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.247-247
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• 2010

DLC(diamond-like carbon)는 비정질 고상 탄소의 하나로 다이아몬드의 유사한 높은 경도, 내마모성, 윤활성, 전기절연성, 화학적 안정성을 가지고 있는 재료이다. 이러한 우수한 특성 때문에 DLC는 박막의 형태로 여러 종류의 보호코팅에 많이 응용되고 있다. DLC의 광범위한 응용에 있어 가장 큰 문제점은 박막이 갖는 높은 잔류응력과 이에 따른 기판과의 낮은 접착성으로 알려져 있다. 최근 연구에 의하면, plasma pre-treatment를 통해 PTFE기판에 DLC박막의 adhesion strength를 증진 시킬 수 있다고 보고하였다. 또한 ion beam technique를 이용하여 잔류응력을 줄이고 기판과의 접착력을 높일 수 있다는 것도 보고 되었다. 이에 기인하여 pre-treatment가 DLC합성에 잔류응력을 낮추고 기판과의 접착성을 높이는 효과를 보일 것이라고 가정하고 연구하였다. 본 연구에서 pre-treatment가 Diamond-like Carbon의 stainless steel 합성시 stress와 adhesion에 어떤 효과가 있는지 알아보기 위해, pre-treatment시와 synthesis of DLC film시에 13.56MHz 150W RF플라즈마 화학기상 증착 (RF-PECVD) 법을 통해 합성되었다. pre-treatment시에 H2(80 sccm), O2(10 sccm), N2(20 sccm)의 가스 종류를 다르게 하였고, synthesis of DLC film시에는 CH4 (20 sccm), H2 (80 sccm)가스의 유량을 고정하였다. 합성된 DLC 박막은 Contact Angle Analyze, Raman spectroscopy, Scratch tester를 이용하여 접촉각, D peak Position, G peak Position, ID/IG ratio, 접착력을 측정하였다.