• Journal of the Korean Society of Groundwater Environment
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• v.5 no.2
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• pp.101-109
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• 1998

Hydraulic property of fissured aquifers often depends on geologic structure which acts main channel of groundwater flow. We treated theories of linear flow related to vertical geologic structure. Then, we analyzed the result of two pumping tests conducted in Okmyeong-ri area (Kyeongbook province) using fractal model and found hydraulic characteristic of the fissured aquifer in this area. According to the pump test analyses, groundwater flow around the holes (pumping well D9; observation wells C3 and D7) of test 1 is linear. and is controlled by vertical geologic structure with infinite length and infinitesimally small width. On the other hand, around the hole D10 (pumping well) of test 2, groundwater flow is pseudo-radial (n=1.9) or radial (n=2). Thus, the characteristic of fractured aquifer often shows variable groundwater flow spatially and temporally.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.521-526
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• 2014

In this study, closed-cell aluminum foam with an initial crack was investigated to produce an axial load-time graph. Using the 10-kN Landmarks of MTS Corporation, a 15-mm/min velocity of mode I shape was applied to the aluminum foam specimen using the displacement control method. ABAQUS 6.10 simulation was used to model and analyze the identical model in three dimensions under conditions identical to those of the experiment. The energy release rate was calculated on the basis of an axial load-displacement graph obtained from the experiment and a transient image of the crack length, and then an FE model was analyzed on the basis of this fracture energy condition. The relation between load and displacement was discussed; it was found that the aluminum foam deformed somewhat less than the adhesive layer owing to the difference in elastic modulus.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.4
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• pp.977-981
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• 2005

Most inflammatory disorders are usually treated using anti-inflammatory drugs including non-steroidal anti-inflammatory drugs (NSAID) and steroidal anti-inflammatory drugs (SAID). In a prolonged use, however, they may frequently produce adverse side-effects. Thus, it is necessarily required to develop a new anti-inflammatory drug with little side-effects. Nephrite has been widely used by traditional oriental medicine to cure the various chronic diseases. In order to verify the anti-inflammatory activity of nephrite, the TPA (12-O-tetradecanoylphorbol-acetate) or the croton oil-induced edema was developed in the mouse ears and the nephrite powder suspension or the nephrite water was directly applied to the ear edema. It was found that nephrite could significantly reduce the ear swelling implying its strong potential as an active anti-inflammatory agent when comparing to indomethacin, a non-steroidal anti-inflammatory drug.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.618-622
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• 2005

Articular cartilage is an important target for studying the arthritic diseases. To verify the therapeutic effects of bee venom herb-acupuncture in vivo, 3${\mu}$l of diluted solution of bee venom for herb-acupuncture were injected into articular cavity once a day during 3 months after making full-thickness defects in rat articular cartilage. Histological examination and immunohistochemistry indicated that the chondrocyte-like tissue was formed during the repair process of cartilage injury, and the expression of a cartilage-specific protein, collagen type II, were significantly activated. It means that the expression of the gene encoding type I collagen was down-regulated, whereas those of collagen type II were up-regulated. Histological examination by hematoxylin-eosin staining indicated that the cells regained their original round morphology. In addition, a homogeneous distribution of articular cartilage extracellular matrices was detected around the cells. These results suggested that bee venom herb-acupuncture was very effective on the recovery of articular chondrocyte phenotype.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.2
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• pp.258-265
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• 2010

Atopic dermatitis (AD) is a chronically relapsing pruritic inflammatory skin disease. To find new anti-inflammatory products for skin inflammatory disease such as AD and contact dermatitis, we produced the effective microorganism fermentation substance (EM-S) by fermentation of medicinal plants with effective microorganisms including photosynthetic bacteria, lactic acid bacteria and yeast, screened the effects of EM-S on NC/Nga model mice. Murine AD-like skin lesions were made by painting Dermatophagoides farinae (Df) extract. Topically applied EM-S significantly reduced clinical severity score, ear thickness and histological grade in AD-like NC/Nga mouse model by Df antigen sensitization. In addition, the serum IgE and Th2 chemokine levels (TARC/CCL17, MDC/CCL22 and CTACK/CCL27) were significantly reduced by EM-S. Futhermore, skin tissue expressions of Th2 chemokines were significantly reduced by EM-S. These results demonstrate that topical application of EM-S may be improve the AD-like skin lesion by suppressing IgE and Th2 chemokines.

• Journal of Korea Water Resources Association
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• v.32 no.3
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• pp.215-223
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• 1999

Recently, measurement of soil moisture contents using TDR (time domain reflectometry) has been proven to be viable technique. The first empirical model proposed by Topp et al. (1980) has been widely used to determine moisture contents of soils from the TDR-measured dielectric constants. However, applicability of the model was limited to medium-textured soils. In this study, we investigate the applicability of the model to sandy-gravelly soils. Calibration experiments consisted of measurement on travel time of electromagnetic waveform along the parallel TDR rods inserted into samples and gravimetric determination of soil moisture contents. The experiments are performed for two sets of samples different in the length and each set consisted of seven different particle size distributions with various gavel contents. The calibration results show that the Topp equation overestimated the measured moisture content for a given dielectric constant by 3 to 8%. We therefore propose new empirical relationships valid for sandy-gravelly soils.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.302-302
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• 2012

최근 비 휘발성 메모리 시장의 확대와 수요가 많아지면서, 비휘발성 메모리 소자의 제작에 대한 연구가 활발히 진행되고 있다. 특히, 실리사이드 나노입자를 적용한 소자는 현 실리콘 기반의 반도체 공정의 적용이 용이하다. 따라서 본 연구에서는 실리사이드 계열의 화합물 중에서 일함수가 4.63 eV인 Vanadium silicide (V3Si) 나노입자 메모리소자를 제작하여 전기적 특성과 열 안정성에 대하여 알아보았다. p-Si기판에 약 6nm 두께의 SiO2 터널층을 건식 산화 방법으로 성장시킨 후 V3Si 나노입자를 제작하기 위해서 V3Si 금속박막을 스퍼터링 방법으로 4 nm~6 nm의 두께로 터널 절연막 위에 증착시켰다. 그리고 컨트롤 절연막으로 SiO2를 초고진공 스퍼터를 이용하여 50 nm 증착하였고, 급속 열처리 방법으로 질소 분위기에서 $800^{\circ}C$의 5초 동안 열처리하여 V3Si 나노 입자를 형성하였다. 마지막으로 200 nm두께의 Al을 증착하고, 리소그래피 공정을 통하여 채널 길이와 너비가 각각 $2{\mu}m$, $5{\mu}m$, $10{\mu}m$를 가지는 트랜지스터를 제작하였다. 제작된 시편의 V3Si 나노입자의 크기와 균일성은 투과 전자 현미경으로 확인하였고, 후 열처리 공정 이후 V3Si의 존재여부의 확인을 위해서 X-ray 광전자 분광법의 표면분석기술을 이용하여 확인하였다. 소자의 전기적인 측정은 Agilent E4980A LCR meter, 1-MHz HP4280A와 HP 8166A pulse generator, HP4156A precision semiconductor parameter analyzer을 이용하여 측정온도를 $125^{\circ}C$까지 변화시키면서 전기적인 특성을 확인하였다. 본 연구에서는 온도에 선형적 의존성을 가지는 전하누설 모델인 T-model 을 이용하여 나노입자 비휘발성 메모리소자의 전하누설 근원을 확인한 후, 메모리 소자의 동작 특성과의 물리적인 연관성을 논의하였다. 이를 바탕으로 나노입자 비휘발성 메모리소자의 열적안정성을 확보하고 소자 특성향상을 위한 최적화 구조를 제안하고자 한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.101-110
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• 2014

Expansion agent is a very effective admixture for prevention of cracking due to autogenous/drying shrinkage and this can induce internal chemical prestress to embedded reinforcement. In this paper, tension-softening and hardening in cement mortar with steel and CSA expansion agent are experimentally evaluated. Cement mortar with steel reinforcement is prepared and tensile strength test is performed for evaluation of cracking and tensile behavior. In spite of slightly reduced strength and elasticity in CSA mortar, significantly increased tension-hardening behavior is evaluated in CSA mortar with induced chemical prestress. Furthermore previous tension softening models are compared with the test results and improvement are proposed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5105-5114
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• 2013

This paper is conducted a research of the cable and filter design considering the deep sea floor environment. The electric architecture which is being used in the subsea plant is comprised of the power supply unit of the high voltage, high-capacity drive system, long cable, and electric motor in the sea area. Conducted emission is occurred by the rapid voltage change at the moment of switching at high speed of inverter for driving motors. The more the length of the cable is lengthened, the worse the motor is influenced by transient voltage. Thus, the over voltage occurred in the drive motor was confirmed by designed wire which is considered R, L, line-to-line C, line-to-gnd C of long cable used in the subsea plant. A guide line of the subsea plant model is also suggested by using a filter to reduce conducted noise of PWM inverter drive-system.

• Explosives and Blasting
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• v.31 no.1
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• pp.41-48
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• 2013

Progressive collapse is generally defined as a local failure of structural members occurring due to abnormal load which results in the partial collapse or total collapse of a structure. Unlike progressive collapse, explosive demolition is a method of inducing the total collapse of structure by removing all or portion of structural members. In explosive demolition the partial collapse of the structural members can be controlled at appropriate time intervals by blasting, to induce the progressive collapse of the structure and control the collapse behavior. In this study, a nonlinear dynamic analysis was carried out in order to apply the progressive collapse process to explosive demolition design of the RC structure. The occurrence of progressive collapse of analytical models was examined according to the number of floors, the removed column height and span length. For models that resisted progressive collapse, progressive collapse resisting capacity was evaluated.