• Journal of the Korean Ceramic Society
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• v.44 no.1 s.296
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• pp.23-31
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• 2007

To examine the effects of chemical admixture on the fluidity and strength development of high chloride cement, experiments were conducted in which lignosulfonate (LS), naphthalenesulfonate (NS), and polycorboxylate (PC) were each added in standard and excessive amounts, and the results were as follows. 1. Because adding KCl to NS causes a decrease in flow, adding PC is better in maintaining high cement fluidity. 2. When cement contained much chloride comes in contact with water, hydration begins 4 h after contact and securing workability becomes difficult, but by adding PC, workability can be secured to 10 h. 3. The bound water ratio and compressive strength in aging 3 days occupy $70\sim80%$ of those in aging 28 days, and the early compressive strength increases not only by adding KCl, but also by chemical admixture. 4. Although compressive strength development is excellent in NS, PC, if NS is added excessively, hydration becomes slow and while the pore structures become slightly minute, the strength development decreases due to severe setting retardation.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.3
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• pp.57-69
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• 2020

Objectives The aim of this study was to investigate the inhibitory effect of ChondroT in indomethacin-induced gastric mucosal injury rat model. Methods Sprague-Dawley rats were randomly assigned to intact, control Joins, Celebrex, ChondroT50 and ChondroT200. Indomethacin (25 mg/kg) was used to induce damage to the gastric mucosal injury. ChondroT was administered by orally to inhibit the indomethacin-induced gastric mucosal injury. At the end of the experiment, pH level in stomach, stomach contents volume, tumor necrosis factor-α (TNF-α) level, interleukin-1β (IL-1β) level, prostaglandin E2 (PGE2) level, myeloperoxidase (MPO) activity, erythrocytes, and thrombocytes were measured. Ophthalmologic and histopathological examination was also analyzed. Results pH level in stomach and Stomach contents volume had no difference between Control, PC-Joins, PC-Cele, ChondroT50 and ChondroT200 group. TNF-α level was decreased in PC-Joins, PC-Cele, ChondroT50 and ChondroT200 group and there were no significant difference. IL-1β level was decreased in PC-Joins group and ChondroT200 group compared to control group. PGE2 level had no significant difference between Control, PC-Joins, PC-Cele, ChondroT50 and ChondroT200 group. MPO level and complete blood count level were decreased in PC-Joins, PC-Cele, ChondroT50 and ChondroT200. Symptom score of ophthalmologic examination was decreased in ChondroT50 and ChondroT200 group compared to control group. Conclusion Based on these results, It could be suggested that ChondroT was effective in reducing damage to the gastric mucosal injury. And further study is needed to conduct a rigorous clinical research.

• Publications of The Korean Astronomical Society
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• v.20 no.1 s.24
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• pp.125-134
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• 2005

In this paper, we propose a small-scale Gigabit VLBI observing system for the Korean VLBI Network (KVN) under construction. The system consists of high-speed sampler, IP-VLBI board, PC-VSI board, and software correlator. Radio signal received by receiver is sampled by high-speed sample. at 1 Gsps (Gigabit sample per second) rate with 2 bits quantization. The digitized signal is recorded in PC and the software correlator does the cross correlation. IP-VLBI board will be used for the geodesy VLBI observation, while PC-VSI board is for the astronomical VLBI observation. The PC-VSI board adopts the VSI-H (VLBI Standard Interface Hardware). The proposed system is based on commercial PCs and therefore can be built inexpensively.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.275.2-275.2
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• 2014

현재 자동차 분야에서 차량 경량화의 한 수단으로 자동차용 유리를 고강도 투명 플라스틱 소재인 Polycarbonate(PC)로 대체하고자 하는 연구가 이루어지고 있다. 하지만, PC의 낮은 내마모 특성과 자외선에 의한 열화 및 변색 현상은 해결하여야 할 문제점으로 지적되고 있으며, 에너지 소비 저감을 위하여 적외선 영역 반사율(reflectance)이 높은 저방사(low emissivity) 특성이 요구되고 있다. 본 연구에서는, ICP-assisted reactive magnetron sputtering 장비를 이용하여 투과율(transmittance)이 확보되고, 고경도 특성을 갖는 Al-Si-N와 300 nm 파장 이하의 자외선 차단 특성이 있는 SiN:H 그리고 저방사 특성을 위해 Al을 증착하였고, 박막의 증착 순서는 SiN:H 박막을 가장 아래에 증착하고 그 위에 Al/Al-Si-N 박막을 다층으로 형성하였다. 박막의 chemical state와 crystallinity를 확인하기 위하여 XPS(X-ray Photoelectron Spectroscopy), XRD (X-ray Diffraction)를 이용하여 분석하였다. Knoop ${\mu}$-hardness tester와 Taber tester를 이용하여 경도 및 내마모 특성을 분석하였다. 제작된 샘플의 Al-Si-N 박막 경도는 Si 비율에 따라 다른 경도 특성을 갖는데, 실제 Si/(Al+Si) 비율이 24%에서 최대 31 GPa의 경도 값을 갖는 것을 확인하였다. UV-Vis Spectrometer를 이용하여 250 nm~700 nm 파장의 투과율을 측정하였고, 자외선 영역의 경우 SiN:H 박막에 의해 300 nm 이하의 파장에서 2% 이하의 투과율을 확인하였다. 그리고 FT-IR(Fourier Transform Infrared Spectroscopy)를 이용하여 $2.5{\mu}m{\sim}15{\mu}m$ 파장의 반사율을 이용하여 방사율을 측정하였는데, 3*(Al/Al-Si-N) 구조의 다층 박막의 경우 방사율은 0.27로 측정되었다.

• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.655-660
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• 1999

Sphingomyelinase (SMase EC:3.l.4.l2) has been suggested to play important roles in the cell cycle, differentiation, apoptosis, inflammation, and the regulation of eukaryotic stress responses. SMase inhibitors may be a powerful tool to elucidate and regulate these cellular responses in which SMase involves. We first isolated an SMase inhibitor, named sphinin, from a strain of soil actinomycetes, F50970. Sphinin inhibited Mg/sup 2+/ -dependent neutral SMase from chicken embryo at 1.2 ㎍/㎖ of IC/sub 50/ Sphinin also inhibited acidic SMase, but it had no inhibitory activity on PI-PLC and PC-PLC, suggesting that sphinin is a specific inhibitor of SMase. The strain F50970 was identified as a Streptomyces sp. by its spiral spore chain, LL-diaminopimelic acid, menaquinone patterns of MK-9 (H'6) and MK-9 (H'8), FA-2c type of fatty acid pattern, and other morphological, physiological, and cultural characteristics.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.110-110
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• 2002

15-Deoxy-$\Delta$12, 14-prostaglandin J2 (15-deoxy-PGJ2), a naturally occurring ligand activates the peroxisome proliferator-activated receptor-$\gamma$(PPAR-$\gamma$). It was known to have promoting ability of nerve growth factor(NGF)-induced neurite extension. However, it is not clear yet as to what signaling pathway is involved in its promoting ability of neurite extension.(omitted)

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.11
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• pp.1623-1630
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• 2011

The effects of addition of citrus peel powders (C 0, 0.5, 1 & 2%), dried Lentinus edodes powders (L 0, 0.5, 1 & 2%), and their combination (C-L) on the chemical, sensory and textural properties of pork sausages were studied. Addition of 0.5, 1 or 2% C, L, and C-L all significantly decreased moisture content, pH, and color a-values of sausage samples, whereas ash content and color b-value were increased (p<0.05). C, L, and C-L did not affect protein, fat, carbohydrates contents or texture characteristics. Sensory evaluation was performed by multivariate data analysis, namely principal component analysis (PCA). Eighty-two percent total variation was observed in the main structured information among the test groups: the first (PC1) and second (PC2) components of variation were 59 and 23%, respectively. Eight parameters (sweet flavor, pork aroma, bitterness, rancidity, salty flavor, color, sour flavor and citrus aroma) were utilized to describe the main sensory characteristic of the sausages. Addition of 0.5, 1 & 2% citrus peel was obviously correlated with PC1 (salty flavor, sour flavor and citrus aroma, pork aroma, and sweet flavor and rancidity), whereas addition of 0.5 & 1% Lentinus edodes was related with PC2 (aroma and rancidity).

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.3
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• pp.168-175
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• 2020

Purpose: The purpose is to test and evaluate the physical properties of commonly used temporary restoration materials and newly emerged materials. Materials and Methods: Four groups of polymer materials were evaluated: Polymethyl methacrylate (PMMA) 2 groups, Polyetheretherketone (PEEK), Polycarbonate. Four physical properties were tested: surface hardness, bending strength, abrasion resistance during wear, wear behavior. The 3-axis bending strength and Vickers hardness test were measured using a universal testing machines respectively. The microstructure was observed with a scanning electron microscope and weight comparison was evaluated after 100,000 chewing tests using a chewing simulator. Kruskal wallis test was performed to evaluate statistical significance. Results: The four groups showed the highest flexural strength and Vickers hardness of PEEK, followed by PC, PMMA-H, PMMA-T. Microstructure observation also showed the least surface roughness in the PEEK group, followed by PC, PMMA-H, PMMA-T. Conclusion: PC is considered to have sufficient mechanical properties that can be applied to the manufacture of temporary teeth. However, further studies, such as biocompatibility, are considered to be necessary for practical clinical applications.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.403-407
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• 2007

The inhibitory effect of the food processing agent on growth of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes was performed with organic acid, and combination of citric acid, acetic acid, propionic acid and vanillic acid. The minimun inhibitory concentration(MIC) of propionic acid was 5,000 ppm in E. coli O157:H7, 2,500 ppm in Salmonella Enteritidis and Listeria monocytogenes. MIC of citric acid was 10,000 ppm in E. coli O157:H7 and Salmonella Enteritidis, 2,500 ppm in Listeria monocytogenes. MIC of acetic acid was 2,500ppm, while in vanillic acid was 5,000 ppm in Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes. MIC of combined organc acid in E. coli O157:H7 were 2,500ppm in PC, 1,250 ppm in PA, PV, CA, CV and AV. MIC of combined organc acid in Salmonella Enteritidis were 2,500 ppm in PC, PA, PV, CA, and CV, 1,250 ppm in AV. MIC of combined organc acid in Listeria monocytogenes were 1,250 ppm in all treatment group. MIC of combined treatment of three organc acid in E. coli O157:H7, S. Enteritidis and L. monocytogenes were 1,250 ppm in PCA, PCV, PAV and CAV. The inhibitory effect of organc acid in E. coli O157:H7, S. Enteritidis and L. monocytogenes could be confirmed from the result of this experiment. Therefore, it was expected that the food process would increase or maintain by using organic acid.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.65-68
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• 2003

Recently, there is a growing concern on the photovoltaic effects using organic materials. This is a phenomena which converts the solar energy into the electrical one. We have fabricated a device structure of ITO/PEDOT:PSS/CuPc/$C_{60}$/BCP/Al. The PEDOT:PSS layer is made by spin coating. and the other organic layers are made by thermal vapor deposition. By measuring the current-voltage characteristics with an illumination of light. we have obtained a value of $V_{oc}$=0.358V and $J_{sc}$=0.338mA/$cm^2$. A fill factor and efficiency are about 0.271 and 0.033%, respectively. A 500W xenon lamp(ORIEL) was used for a light source, and the light intensity illuminated into the device was about 10mW.