• Journal of the Korean Society for Heat Treatment
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• v.32 no.5
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• pp.224-229
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• 2019

PVD coating is a technology that can be applied to various industries, and is widely used for processing molds and machinery, improving performance of core parts, and extending the life. Therefore, there is a need for a research on a device and a process technology that can adjust the performance to suit each application. In this study, a PVD coating device with ion density control was used to deposit a coating layer on SKD 11, a cold die steel, with magnetron currents of 1 A, 2 A, 3 A at arc currents of 80 A, 100 A, 130 A. It examined the mechanical properties for each condition. Increasing the arc current and magnetron current could improve the thickness, adhesion, and hardness of the coating layer. Especially, When the magnetron current was high, it suppressed the droplets that could be generated by the high arc current, showing excellent surface uniformity and adhesion of the coating layer.

• Journal of Periodontal and Implant Science
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• v.28 no.2
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• pp.249-264
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• 1998

The present study evaluates the effects of calcium sulfate and DFDB on alveolar bone regeneration and cementum formation and connective tissue adhesion in intrabony angulated 1 wall defects of dogs. Four millimeter-deep angulated one-wall intrabony defects were surgically created in the mesial & distal aspects of premolars and with flap operaion alone(control group), with calcium sulfate(experimental group 1), with composit graft of 50% calcium sulfate and 50% DFDB(experimental group 2), with DFDB alone(experimental group 3). Histologic analysis following 8 weeks of healing revealed the following results: 1. The lengths of connective tissue adhesion was $1.05{\pm}0.48mm$ in the control, $1.30{\pm}0.67mm$ in the test group I, $0.97{\pm}0.22mm$ in the test group II and $0.93{\pm}0.15mm$ in the test group III. There was no statistical significance between control and all experimental groups. 2. Changes in alveolar bone level was $0.97{\pm}0.27mm$ in the control group, $1.45{\pm}0.42mm$ in the test group I, $2.00{\pm}0.33mm$ in the test group II, $1.88{\pm}0.34mm$ in the test group III. There was no statistically significant difference between control and experimental group I. There was a statistically significant difference between the control and experimental group II,III.(p<0.05). There was no statistically significant difference between all experimental group. 3. Cementum formation was $1.13{\pm}0.17mm$ in the control, $1.78{\pm}0.31mm$ in the test group I, $2.17{\pm}0.38mm$ in the test group II, $2.15{\pm}0.47mm$ in the test group III with statistically significant differences between control group and all experimental group(P<0.05). There was no statistically significant differences between all experimental group. These results suggest that the use of composit graft of 50% calcium sulfate and 50% DFDB and DFDB alone in angulated 1 wall intrabony defects has little effects on connective tissue adhesion, but has significant effects on new bone and new cementum formations.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.79-86
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• 2021

For a preliminary study on a thrust-throttleable Variable Flow Ducted Rocket, a gas generator and flow control valve were developed, and ground combustion tests were performed. The gas generator and flow control valve operated at the required performance level for parameters, such as heat-resistance, combustion-time, pressure, and temperature. The combustion characteristics of a fuel-rich solid propellant mixed with Boron/MgAl/AP, etc., were also analyzed. A Plunger-type flow control valve was designed to control the discharge flow area, and it was confirmed that the flow control valve was able to control the combustion gas flow rate and pressure. However, due to the reduction of the discharge flow area caused by adhesion of combustion products, the combustion pressure continuously increased. The analysis of the pressure increase is covered in Part 2 of this paper.

• Tuberculosis and Respiratory Diseases
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• v.44 no.6
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• pp.1256-1262
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• 1997

Background : Leukocyte-endothelial adhesion molecules have been implicated in the pathogenesis of inflammatory disease. ICAM-1, VCAM-1 and E-selectin are cell surface adhesion molecule on vascular endothelial cells. They are up-regulated by inflammatory cytokines and regulate the adhesion and migration of leukocytes across the endothelium. Tuberculosis, a granulomatous disorder is an infection caused by Mycobacterium tuberculosis. The clinical manifestations of tuberculosis are dependent on the cellular immune response to tubercule bacilli. Circulating adhesion molecules are probably formed by cleavage and release into the circulation of the extracellular domain of the membrane bound form. The elevated levels of circulating adhesion molecules have been reported in numerous disease state. To evaluate their role as markers of disease activity in tuberculosis, we measured a sE-selectin, sVCAM-1 and sICAM-1 levels in the serum with severities of mild, moderate and far advanced pulmonary tuberculosis. Methods : The control and test groups were divided as follows. Group I : control(n=5), Group II : patients with mild pulmonary tuberculosis(n=12), Group III : pateints with moderate pulmonary tuberculosis(n=20), Group IV : patients with far advanced pulmonary tuberculosis(n=19). Serum sICAM-1, sVCAM-1 and sE-selectin were measured by ELISA kit Results : Serum soluble adhesion molecules are elevated in patients with pulmonary tuberculosis, Circulating ICAM-1 levels were significantly elevated in patients with moderate and far advanced pulmonary tuberculosis when compared with control group. When compared with control group, serum sVCAM-1 levels showed significant elevation in patients with mild, moderate and far advanced pulmonary tuberculosis. Serum sE-selectin levels were significantly elevated in patients with far advanced pulmonary tuberculosis when compared with control group. Conclusion : These results suggest that sICAM-1, sVCAM-1, and sE-selectin may be invloved in the pathogenesis of tuberculosis. And, particularly, sICAM-1 and sVCAM-1 may be useful markers of the disease activity.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.635-642
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• 2004

In electric motor coaches. the rolling stocks move by the adhesive effort between rail and driving wheel. Generally, the adhesive effort is defined by the function of both the weight of electric motor coach and the adhesive effort between rails and driving wheel. The characteristics of adhesive effort is strongly affected by the conditions between rails and driving wheel. When the adhesive effort decreases suddenly, the electric motor coach has slip phenomena. This paper proposes a re-adhesion control based on disturbance observer and sensor-less vector control. The numerical simulation and experimental results point out that the proposed readhesion control system has the desired driving wheel torque response for the tested bogie system of electric coach. Based on this estimated adhesive effort, the re-adhesion control is performed to obtain the maximum transfer of the tractive effort.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.5
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• pp.635-641
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• 2011

Anti-atherogenic effects in tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$)-stimulated human umbilical vein endothelial cells (HUVEC) are involved with suppressed oxidative stress, cell adhesion molecules, and pro-inflammatory factors. The aim of this study was to determine whether green tea seed coat ethyl acetate fraction (GTSCE) could modulate cell adhesion molecules and inflammatory mediators in HUVEC stimulated with TNF-${\alpha}$. Nitric oxide (NO) production was significantly increased in TNF-${\alpha}$-stimulated HUVEC compared to TNF-${\alpha}$ only treated cells. The NO that is produced by endothelial nitric oxide synthase dilates blood vessels and has protective effects against platelet and leucocyte adhesion. GTSCE at 25, 50, 75, and $100\;{\mu}g$/mL significantly (p<0.05) reduced TNF-${\alpha}$ production. GTSCE significantly (p<0.05) inhibited soluble vascular cell adhesion molecule-1 level, in a dose-dependent manner. Monocyte chemoattractant protein-1 level was also significantly (p<0.05) inhibited by GTSCE treatment at $75\;{\mu}g$/mL compared to the TNF-${\alpha}$-only treated group. Total antioxidant capacity by GTSCE was significantly (p<0.05) enhanced compared to the TNF-${\alpha}$-only treated group. These results suggest that GTSCE can inhibit the production of cell adhesion molecules and inflammatory mediators and could be used as a candidate bioactive material to prevent the development of atherosclerosis.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.3
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• pp.245-253
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• 2011

Purpose: The aim of this in vitro study was to estimate surface characteristic after peptide coating and investigate biological response of human mesenchymal stem cell to anodized titanium discs coated with RGD peptide by physical adhesion and chemical fixation. Materials and methods: Fluorescence isothiocyanate (FITC) modified RGD-peptide was coated on the anodized titanium discs (diameter 12 mm, height 3 mm) using two methods. One was physical adhesion method and the other was chemical fixation method. Physical adhesion was performed by dip and dry procedure, chemical fixation was performed by covalent bond via silanization. In this study, human mesenchymal stem cell was used for experiments. The experiments consisted of surface characteristic evaluation after peptide coating, analysis about cell adhesion, proliferation, differentiation, and mineralization. Obtained data are statistically treated using Kruskal-Wallis test and Bonferroni test was performed as post hoc test (P=.05). Results: The evaluation of FE-SEM images revealed no diffenrence at micro-surfaces between each groups. Total coating dose was higher at physical adhesion experimental group than at chemical fixation experimental group. In cell adhesion and proliferation, RGD peptide coating did not show a statistical significance compared with control group (P>.05). In cell differentiation and mineralization, physical adhesion method displayed significantly increased levels compared with control group and chemical fixation method (P<.05). Conclusion: RGD peptide coating seems to enhance osseointegration by effects on the response of human mesenchymal stem cell. Especially physical adhesion method showed more effective than chemical fixation method on response of human mesenchymal stem cell.

• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.467-472
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• 2005

Asphalt emulsion is manufactured by the emulsification of asphalt, and is considered as an energy-saving, ecologically safe material because it does not need any heating processes with gas emission and fire hazard in its use. This study is concerned with evaluating the feasibility of the use of an asphalt emulsion as a poly-meric admixture. Asphalt-modified mortars using an experimentally manufactured asphalt emulsion were prepared with various polymer-cement ratios, and tested far the mechanical properties such as strengths and adhesion and the properties related to durability such as water absorption, permeation, carbonation and chloride ion penetration. As a result, the waterproofness, carbonation resistance and chloride ion penetration resistance of the asphalt-modified mortars were markedly improved with an increase in the polymer-cement ratio, but their compressive strength and adhesion to mortar substrates were reduced with increasing polymer-cement ratio. Therefore, it is recommended to control their polymer-cement ratio to be $10\%$ or lower in their practical applications. Further study to improve their compressive strength and adhesion is needed.

• Journal of Technologic Dentistry
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• v.29 no.2
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• pp.213-223
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• 2007

The success of a porcelain fused to metal (PFM) restoration depends upon the quality of the porcelain-metal bond. The adhesion between metal substructure and dental porcelain is related to the diffusion of oxygen to the reaction layer formed on cast-metal surface during firing. The purposed of this investigation was to study the effects of gold based bonding agent on Ni-Cr alloy-ceramic adhesion between porcelain matrix, gold based bonding agent and metal substructure interface. gold based bonding agent have been applied as an intermediate layer between a metal substructure and a ceramic coating. gold based bonding agent(Aurofilm NP, Metalor, Swiss) was applied on Ni-Cr alloy surface by four method. Surfaces only air abraded with 110${\beta}\neq$ Al2O3 particles were used as control. metal ceramic adhesion was evaluated by a biaxial flexure test(N=5) and volume fraction of adherent porcelain was determined by SEM/EDS analysis. Result of this study suggest that the layering sequence of gold based bonding agent is very important and can improve porcelain adherence to PFM.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.41-42
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• 2012

High temperature / high pressure spray equipment using a conventional method, unlike spray polyurea adjustable pot life and yellowing caused by UV light and chemicals do not occur, or discoloration of Self-Leveling Type of rugged hand-polyurea resin for technology development is underway. This new concept of polyurea resin roller, brush, airless spray, and they installed easily using the unfamiliar labor, and curing time of approximately four hours to gain control of the glass because it is Pot. Construction, but does not like the spray polyurea resin, compared to the existing degradation of the adhesion strength is concerned. In this study, Self-Leveling Type Manual of polyurea resin adhesion strength of target deterioration Let's minimize problems by reviewing existing domestic and infrastructure long-term durability for long life of the facility is to obtain.