• Polymer(Korea)
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• v.35 no.4
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• pp.342-349
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• 2011

The effect of the amount of vinyltriethoxysilane (VTEOS) in precipitated silica filled silicone rubbers was extensively investigated in terms of the change of mechanical properties, heat resistance, oil resistance, compression set, resilience, and curing characteristics. As the content of VTEOS increased from 0 to 2.0 phr, the hardness of the silicone rubber increased, however, tensile strength, elongation at break, and tear strength decreased. From heat resistance test, the change of mechanical properties was pronounced for silicone rubber treated with more VTOES. The best heat resistance was achieved at 2.0 phr VTOES. In addition, oil resistance was proportionally improved with VTEOS content. From oil resistance test. it was found that the decrease in hardness and maximum elongation was reduced for VTEOS-added systems. Finally, resilience, compression set, degree of cure and crosslink density were significantly enhanced with the amount of VTEOS.

• Journal of Digital Convergence
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• v.11 no.4
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• pp.339-350
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• 2013

The decreased body, liver, kidney, spleen and testis weights of guinea pigs by TCDD (2,3,7,8-tetracholorodibenzo-${\rho}$-dioxin) treatment (TT) were statistically significantly increased after treating red ginseng saponin fraction (SF) (p>0.01). After treated with SF, the decreased hematocrits values and numbers of RBC and platelet, activity of amylase and lactate dehydrogenase, levels of uric acid, total protein and albumin by TT were increased, and the increased numbers of WBC, levels of triglyceride, total cholesterol (TC), LDL-cholesterol, HDL-cholesterol, creatinine, blood urea nitrogen, calcium and phosphorus, activities of creatinine kinase, aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase were decreased after treated with SF. And they all had a statistical significance (p>0.01) except for RBC, WBC, platelet, blood glucose, TC, calcium and albumin. From these results, we knew that SF mollified the acute toxicity induced by TCDD in guinea pigs.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.6
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• pp.1049-1053
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• 2009

This study was carried out to investigate the effects of Eucommia ulmoides Oliver (Du-Zhong) as a main ingredient in a mixture of various medicinal herbal extracts on blood pressure, serum lipid concentrations, and hematological variables in hypertensive patients. After 4 weeks on drinking the mixed medicinal herbal teas, systolic blood pressure remarkably decreased from 167.14 to 134.86 mmHg and diastolic blood pressure decreased from 100.00 to 87.10 mmHg. In terms of serum lipid profiles, there were no differences in total-cholesterol, HDL-cholesterol, LDL-cholesterol level, and atherogenic index, However, the level of triglycerol was significantly reduced from 237.1 before the experiment to 145.00 mg/dL after 4 weeks on drinking the mixed medicinal herbal teas. Serum triglyceride were remarkably reduced from 237.1 to 145.00 mg/dL in the hypertensive patients who had taken the combined medicinal herbal extracts. Compared with data obtained from the patients before the experiment, there were no differences in hematological variables (RBC, WBC, hematocrit, hemoglobin, platlets and homocysteine) after the 4 weeks experiments, but mean corpuscular hemoglobin concentration was significantly increased by 2.70% (p<0.05) in the blood samples. Based on these findings, it can be presumed that the examined mixed medicinal herbal tea may be effective in lowering blood pressure and in increasing mean corpuscular hemoglobin concentration due to reduced serum triglyceride levels in hypertension patients.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.3
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• pp.201-220
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• 2023

Power cable tunnels is one of the underground structures meant for electricity transmission and are constructed using shield TBM method when transitting across urban and subsea regions. With the increasing shaft depth for tunnels excavation when the shield TBM excavated the rock mass, the review of selecting closed-type shield TBM in rocks becomes necessary. A simplified shield TBM design method is also necessary based on conventional geotechnical survey results. In this respect, design method and related design program are developed based on combined results of full-scale tests, considerable amount of accumulated TBM data, and numerical simulation results. In order to validate the program results, excavation data of a completed power cable tunnel project are utilized. Thrust force, torque, and power of shield TBM specification are validated using Kernel density concept which estimates the population data. The robustness of design expertise is established through this research which will help in stable provision of electricity supply.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.1-10
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• 2023

Due to the development of the industrial revolution, regulations on exhaust emissions have been continuously strengthened to reduce the rapidly increasing greenhouse gas emissions. The use of environmentally friendly fuels is essential to meet these regulations. Hydrogen has been attracting attention as a future environmentally friendly fuel, but due to its material properties, it faces significant challenges in handling and storage. As an alternative, ammonia has been proposed. Ammonia can be easily liquefied at room temperature compared to hydrogen and has a high energy density. In order to examine the applicability of ammonia as an engine fuel, experiments were conducted to investigate the effects of changes in combustion control parameters in a direct injection ammonia combustion engine. The experiments were conducted by varying two variables: spark timing and excessive air ratio. Observations were made on combustion stability and the trends of exhaust emissions such as nitrogen oxides and unburned ammonia under the conditions of an engine speed of 1,500 rpm and medium to high loads (brake torque of 200 Nm). By optimizing the combustion control parameters, conditions for stable combustion even when using ammonia as the sole fuel were identified, and plans are underway to apply strategies for future expansion of the operating range.

• Korean journal of applied entomology
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• v.59 no.2
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• pp.93-107
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• 2020

Adults of seven noctuid potential pests (Spodoptera frugiperda, S. litura, S. exigua, Ctenoplusia agnata, Mythimna loreyi, Athetis dissimilis, and A. lepigone) of soybean and maize in Suwon, Korea were identified by their morphological characteristics in the wing pattern and male genitalia and partial mitochondrial DNA sequences of cytochrome c oxidase subunit 1 gene. The generation number of adults that emerge annually in six species (except A. lepigone) was estimated from the data on density fluctuations of adults caught in sex pheromone traps in 2019 and the forecasted data using temperature-associated development and reproduction models for those species. S. frugiperda adults were caught from July 27th to October 31st in 2019, and hence were initially estimated to emerge three times per year. But, it was finally expected that S. frugiperda adults could possibly emerge a total of four times per year in Suwon, considering larval emergence observed during mid- and late June in other areas. Adult emergence of S. litura, S. exigua, C. agnata, and M. loreyi in 2019 was observed from May 29th to November 6th, from May 14th to November 6th, from May 26th to October 25th, and from May 31st to November 23rd, respectively. Annual adult emergence of these four species was estimated as at least four times. Adults of A. dissimilis were caught from May 26th to September 11th in 2019, and adult emergence was estimated at only twice per annum. It was postulated that the first adult populations of five species except the two Athetis species were probably migrated from other areas.