• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.107-108
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• 2022

In recent years, the construction industry has a tendency to increase of high-rise builidngs. High rise buildings can use limited space efficiently. But High rise buildings have problem that have extremely heavy weight. Various studies are being conducted to reduce the weight of buildings. Although lightweight aggregate is a meterial that can effectively reduce the weight of buildings, the strength of the aggregate itself is weak and the absorption rate is high, so the strength of the ITZ(Interfacial Transition Zone) area is weak. Therefore, it is essential to improve the interfacial area when using lightweight aggregates. In this study, an experiment was conducted to improve the adhesion between the aggregate and cement paste and to strengthen the interfacial area by coating the surface of the lighteight aggregate with Blast Furnace Slag. To confirm the improvement, compressive strength and EIS(Electrochemical Impedance Spectroscopy) measurements were perfromed. Using EIS, the change in electrical resistance of the cement hardened body was confirmed. As a result, it was confirmed that the lightweight aggregate coated on the surface showed highter compressive strength and electrical resistance than the non-coated lightweight aggregate, and that the coating material was filled in the interfacial area and inside the aggregate that helped to strengthen the compresssive strength and higher electrical resistance.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.2_2
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• pp.371-375
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• 2024

Epoxy resins are widely used in various fields due to their high adhesion, mechanical strength, and solvent resistance. However, as the volume decreases during the hardening process and the cooling process after hardening, stress is generated and when an external force is applied, the brittle material exhibits destruction behavior. To complement this, research has been conducted using inorganic nanofillers such as halloysite nanotube(HNT). HNT has a nanotube structure with the chemical formula of Al₂Si₂O₅(OH)₄·nH₂O and is a natural sediment of aluminosilicate. It has been used as additive to improve the mechanical properties of epoxy composites with exchange of amine group as a terminal functional group. In order to simplify complicated procedures of common wet method, a dry coating machine was designed and used for amine group exchange in previous research. In this study, they were applied as filler in epoxy composites, and mechanical properties such as tensile strength and flexural strength of composites were examined.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.998-1007
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• 2016

The objective of this study was to investigate the effects of a lettuce (Lactuca sativa L.) extract on the inflammation of human umbilical vein endothelial cell (HUVEC) and blood lipid improvement in hypercholesterolemic mice fed a high cholesterol diet. The lettuce extract (100% ethanol extract) inhibited the expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 in HUVEC treated with tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$). The lettuce extract suppressed the adhesion of THP-1 to TNF-${\alpha}$-treated HUVEC. The lettuce extract decreased the TNF-${\alpha}$-stimulated production of proinflammatory cytokine interleukin-6, interleukin-8 and chemokine monocyte chemotactic protein 1. In hypercholesterolemic mice, the lettuce extract reduced serum total cholesterol, triglyceride, and low-density lipoprotein-cholesterol level, while the lettuce extract elevated high-density lipoprotein-cholesterol level, resulting in the decrease of atherogenic index and cardiac risk factor level. These results suggested that lettuce extract can be an useful resource to show an anti-inflammatory effect and improve lipid metabolism.

• Journal of the Korean Geosynthetics Society
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• v.20 no.1
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• pp.35-44
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• 2021

This research studies the stabilization method for improved soil sloped through the on-site application of Paper Flyash ground stabilizers. The target strength required for improved soil is 500 kPa, and the compressive strength for the slope surface needs to be less than 1,000 kPa after the improvement in order to plant vegetation. To meet this condition, we mixed soil from the site and the ground stabilization material, which is the main material for surface improvement material, performed mixing design and conducted various tests including strength test, permeability test and plantation test. After analyzing the results of the compression test on improved soil slope, we proposed soil constants for the improved soil. In order to evaluate the applicability of the improved soil on the slope, the site construction was carried out on the collapsed slope and the reinforcement evaluation of the surface of the improvement soil was conducted. The stability was not secured before the reinforcement, but the test shows after the reinforcement with improved soil, the safety rate is secured up to 48 hours during the raining period. In addition, the compressive strength of the improved soil at the site was secured at more than 200 kPa adhesion as planned, and the soil hardness test result was also found to be within the specified value of 18-23 mm, which increased the resistance to rainfall and ability to grow plant on the surface for improved soil.

• Tuberculosis and Respiratory Diseases
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• v.46 no.4
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• pp.481-488
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• 1999

Background: The routine application of the combined regimen of corticosteroid-antituberculosis therapy to the tuberculous pleurisy remains controversial. Steroid therapy to tuberculous pleurisy could be effective on the acceleration of absorption of pleural effusion and symptom improvement, but there has been debate about the effect of prednisolone on the prevention of pleural adhesion. So we studied the efficacy of combined regimen of prednisolone-antituberculosis therapy on the absorption of pleural effusion and prevention of pleural adhesion. Method: A prospective, randomized study was performed in 82 patients, 50 patients(non-steroid group) were treated with only antituberculosis regimen for 6 months and in 32 patients(steroid group) prednisolone(30mg/day) were administered in addition to antituberculosis regimen for one months and tapered for another month. The amount of pleural effusion was compared at the beginning of treatment, 2nd month, 6th month and final visit with chest X-ray findings which were graded from grade 0(complete absorption) to grade 6(near total haziness). Results: The amount of pleural effusion of steroid group at 2nd month, 6th month and final visit was lesser than that of non-steroid group(P<0.05). The incidence of the complete absorption of the pleural effusion was 3/32(9.4%) in steroid group, 1/50(2%) in non-steroid group at 2nd month after treatment; and 12/32(37.5%) in steroid group, 6/50(12%) in non-steroid group at 6th month after treatment(P<0.05). At final observation, the incidence of residual pleural thickening was 15/32(47%) in steroid group and 37/50(74%) in non-steroid group(P<0.05). No serious side effects were noted during the treatment with prednisolone. Conclusion: The administration of prednisolone in conjunction with antituberculosis chemotherapy improved the absorption of pleural effusion and decreased the residual pleural thickening.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1167-1177
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• 1998

Background : Pulmonary tuberculosis is one of the diseases characterized granuloma formation which was controlled by cellular immune reactions. In the process of granulomatous changes, activated alveolar macrophages and T lymphocytes secrete many cytokines including interleukin-1 (IL-1), tumor necrosis factor-alpha(TNF-$\alpha$), interferon-gamma(IFN-$\gamma$) which mediate inflammatory reactions. Intercelluar adhesion molecule-1(ICAM-1) also known to major role player in inflammatory processes, and increased cellular expressions when endothelial cell was stimulated by IL-1, TNF and IFN. Method : To evaluate relationships among cellular immune reactions and clinical stages, pulmonary tuberculosis patients were classified into three groups according to their clinical stages including minimal, moderate and far advanced tuberculosis. TNF-$\alpha$ IFN-$\gamma$, sICAM-1 (soluble form of ICAM-1) were measured at the time of diagnosis and after 6-months anti-tuberculosis medications by radioimmuno assay or enzyme linked immunosolvent assay. Result : TNF-$\alpha$, IFN-$\gamma$, sICAM-1 were significantly increased in moderate and far advanced pulmonary tuberculosis patients but no meaningful changes in minimal staged patients. 6-months anti-tuberculosis medications reduced serum sICAM-1 levels significantly, related to clinical improvement but no significant changes were found in the serum levels of TNF-$\alpha$ and IFN-$\gamma$. In the point of correlations. positive ones revealed between TNF-$\alpha$ and sICAM-1, also between IFN-$\gamma$ and sICAM-1 but no correlation between TNF-$\alpha$ and IFN-$\gamma$. Conclusion : Measurement of serum sICAM-1 could be useful parameter to evaluate the severity of pulmonary tuberculosis and to monitor disease activities during anti-tuberculosis medications.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.197-197
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• 2016

Commercially pure titanium (CP Ti) and Ti-6Al-4V alloys have been widely used for biomedical applications. However, the use of the Ti-6Al-4V alloy in biomaterial is then a subject of controversy because aluminum ions and vanadium oxide have potential detrimental influence on the human body due to vanadium and aluminum. Hence, recent works showed that the synthesis of new Ti-based alloys for implant application involves more biocompatible metallic alloying element, such as, Nb, Hf, Zr and Mo. In particular, Nb and Hf are one of the most effective Ti ${\beta}-stabilizer$ and reducing the elastic modulus. Plasma electrolyte oxidation (PEO) is known as excellent method in the biocompatibility of biomaterial due to quickly coating time and controlled coating condition. The anodized oxide layer and diameter modulation of Ti alloys can be obtained function of improvement of cell adhesion. Manganese(Mn) plays very important roles in essential for normal growth and metabolism of skeletal tissue in vertebrates and can be detected as minor constituents in teeth and bone. Radio frequency(RF) magnetron sputtering in the various PVD methods has high deposition rates, high-purity films, extremely high adhesion of films, and excellent uniform layers for depositing a wide range of materials, including metals, alloys and ceramics like a hydroxyapatite. The aim of this study is to research the Mn coatings on the micro-pore formed Ti-29Nb-xHf alloys by RF-magnetron sputtering for dental applications. Ti-29Nb-xHf (x= 0, 3, 7 and 15wt%, mass fraction) alloys were prepared Ti-29Nb-xHf alloys of containing Hf up from 0 wt% to 15 wt% were melted by using a vacuum furnace. Ti-29Nb-xHf alloys were homogenized for 2 hr at $1050^{\circ}C$. Each alloy was anodized in solution containing typically 0.15 M calcium acetate monohydrate + 0.02 M calcium glycerophosphate at room temperature. A direct current power source was used for the process of anodization. Anodized alloys was prepared using 270V~300V anodization voltage at room. Mn coatings was produced by RF-magnetron sputtering system. RF power of 100W was applied to the target for 1h at room temperature. The microstructure, phase and composition of Mn coated oxide surface of Ti-29Nb-xHf alloys were examined by FE-SEM, EDS, and XRD.

• Journal of Conservation Science
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• v.31 no.4
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• pp.373-386
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• 2015

This study identified degradation properties by temperature stress with Araldite$^{(R)}$ AY103-1/HY956 used for ceramics. Tensile and compressive strength of durability increased for 6,480 hours at temperature of $34{\sim}45^{\circ}C$. In stability of external stress and temperature, compressive strength is superior to tensile strength, it requires conservation plans considering strength properties and stress of restoration materials. The tensile shear strength of adhesion properties decreased for 4,320 hours at temperature of $40{\sim}60^{\circ}C$. In ceramics with porosity, environments under isothermal-isohumidity are important because interfacial properties of adherend are concerned with performance variation. Glossiness decreased for 6,480 hours at temperature of $34{\sim}45^{\circ}C$ and color difference increased. Gloss stability was superior and color stability was weak, which requires improvement of optical properties. In artifacts on display in museums, there is concern about temperature rise on restoration materials by lighting therefore, it needs to minimize change in physical properties by exposure environments.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.4
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• pp.43-48
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• 2007

This study is focused on the effect of the surface properties for the post electrode, which is used in pad formation consisted of SMT such as IC, passive component, combined with fired LTCC substrate, We carried out the surface microstructure of sintered electrode and the basic reliability evaluations with sample fired by microwave sintering to solve the problems occurred in post electrode by electric sintering. We evaluated surface densification status of post electrode according to various conditions of microwave sintering. In additions, it is obtained strong effect on blister improvement of post electrode because of over-sintering and the insufficient out gas in bum out process. As a result of adhesion strength, we confirmed $44.3N/mm^2$ in microwave sintering and $34.5N/mm^2$ in electric sintering, respectively. This result will be used for the basic reliability test. Finally, microwave sintering seems to be economic in process time with 30 min compared to electric sintering with 10 hr. In terms of Mass production and efficiency, microwave sintering are excepted to be higher than electric sintering.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.525-531
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• 2016

Cynanchum wilfordii Radix (CWR), Arctium lappa L (ALL), and Dioscorea opposite (DO) have been known to improve blood lipid profile, blood pressure, and inflammation. To find the optimal combination ratio of CWR, ALL, and DO in terms of vascular health improvement, we compared the effects of various combinations on gene expression of Vascular cell adhesion protein 1 (VCAM-1) in human aortic smooth muscle cells (HASMC). VCAM-1 mediates endothelial leukocyte adhesion and is upregulated in atherosclerosis. Cells was stimulated by TNF-α (10 ng/㎖, 2h) and treated with various combinations for 24 h. A combination (CADM5, CWR:ALL:DO = 2:1:1) showed the strongest suppression of VCAM-1 so that CADM5 was chosen for further experiments. We performed cell viability test with CADM5 (0, 3.125, 12.5, 25, 50, and 100 ㎍/㎖) and no cytotoxicity was found. We also investigated the effect of CADM5 on protein expression of VCAM-1, ICAM-1, Nrf-2, and HO-1 using western blotting. We found that CADM5 diminished the expression of VCAM-1 and increased the expression of Nrf-2 and HO-1. Therefore, we concluded that CADM5 (CWR:ALL:DO = 2:1:1) effectively improves vascular health by regulating the expression of VCAM-1.