• 한국군사과학기술학회지
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• 제15권1호
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• pp.81-85
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• 2012

This work is related to study the thermal decomposition of 1,3,5-trinitro-1,3,5-triazacylohexane(RDX) by differential scanning calorimeter and thermo-gravimetry with Kissinger's & Iso-conversional method under nonisothermal conditions, with heating rate from 2 to $8^{\circ}C$/min or given heating rate. We calculated and compared activation energy with these two methods. Iso-conversional method is better than Kissinger's method to study decomposition mechanism. We also investigated activation energy and frequency factor by Kissinger's & Iso-conversional method with the influence of particle size. In case of single crystal, Cl-3(large crystal) has better thermal stability than Cl-5(small crystal). The activation energy increased according to the size of the particle size.

• 대한의생명과학회지
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• 제18권4호
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• pp.345-354
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• 2012

Angelica keiskei has exhibited numerous pharmacological effects including antitumor, antimetastatic, and antidiabetic effects. However, the anti-inflammatory effects and mechanisms employed by xanthoangelol E isolated from Angelica keiskei are incompletely understood. In this study, we attempted to determine the effects of Xanthoangelol E on the lipopolysaccharide (LPS)-stimulated mouse peritoneal macrophage. The findings of this study demonstrated that xanthoangelol E inhibited the production of tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-6, and prostaglandin $E_2$ ($PGE_2$). Xanthoangelol E inhibited the enhanced levels of cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) caused by LPS. Additionally, we showed that the anti-inflammatory effect of xanthoangelol E is through the regulation of the activation of nuclear factor (NF)-${\kappa}B$ and caspase-1. These results provide novel insights into the pharmacological actions of xanthoangelol E as a potential candidate for the development of new drugs to treat inflammatory diseases.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.609-614
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• 2001

This paper is to explain reasonable shear behavior that can apply usually to reinforced concrete beams on the basic concepts of existent analysis and experimental research information. This study is succession $paper^{2) 3) 4) 5)}$ of treatise announced in existing and main control variable of reinforced concrete beams with stirrups used internal force state factor($\alpha$). Shear failure of reinforced concrete beams with stirrups is Influenced greatly because of the actual geometrical shape(a/d) of the concrete and flexural reinforcement steel ratio, stirrup reinforcement ratio and concrete compression strength, size effect etc. Therefore, shear behavior of reinforced concrete beams with stirrups that flexural crack is happened can be explained easily through proper extent proposal of internal force state factor($\alpha$) that express internal force state flowing. Use existent variable truss model by analysis model to explain arch action. Also, wish to compose each failure factors and correlation with internal force state factor by function, and when diagonal cracks happens, internal force state factor($\alpha$) study whether shear stress and some effect are.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권2호
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• pp.93-96
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• 2014

RFID (Radio Frequency IDentification) system is recognition technology which can maintain various object's information. Reliability of RFID tags is the most important factor in RFID system. In this paper, we proposed ALT (Accelerated Life Test) method for UHF RFID tags. Temperature and humidity were adopted as stress factors and the accelerated life tests were conducted in three different conditions. We performed failure analysis for identifying failure mechanism and statistical analysis of test data. In the statistical analysis, we employed Inverse Power law for relationship between tag's life and stress. Through the statistical analysis, we proposed acceleration factor for several levels of temperature-humidity. The reliability qualification test plans were also designed for the tag's target reliability.

• 한국지반공학회논문집
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• 제20권8호
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• pp.97-102
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• 2004

본 논문은 기존의 한계 평형법 보다 사면의 파괴거동을 잘 묘사할 수 있는 유한요소법에 의한 사면의 안전율을 결정하는 방법에 대하여 기술하였다. 특히, 지하수위를 고려하는 사면의 파괴거동을 강도감소법에 의한 유한요소법으로 산정하였다. 그 결과, 강도 감소법을 이용한 FEM해석방법이 사면의 안정해석에 대하여 파괴거동과 안전율을 구하는데 유효한 수단임을 보여 주었다. 그리고 지하수 상승경우와 지하수 급강하 사면의 경우에 대하여 자세히 분석하였으며, 한계평형법인 Bishop간편법 해석결과와 비교, 검토하였다.

• Geomechanics and Engineering
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• 제11권4호
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• pp.553-570
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• 2016

A series of three-dimensional (3D) parametric finite element analyses have been performed to study the influence of the relative locations of pile tips with regards to the tunnel position on the behaviour of single piles and pile groups to adjacent tunnelling in weathered soil. When the pile tips are inside the influence zone, which considers the relative pile tip location with respect to the tunnel position, tunnelling-induced pile head settlements are larger than those computed from the Greenfield condition. However, when the pile tips are outside the influence zone, a reverse trend is obtained. When the pile tips are inside the influence zone, the tunnelling-induced tensile pile forces mobilised, but when the pile tips are outside the influence zone, compressive pile forces are induced because of tunnelling, depending on the shear stress transfer mechanism at the pile-soil interface. For piles connected to a cap, tensile and compressive forces are mobilised at the top of the centre and side piles, respectively. It has been shown that the increases in the tunnelling-induced pile head settlements have resulted in reductions of the apparent factor of safety up to approximately 43% when the pile tips are inside the influence zone, therefore severely affecting the serviceability of the piles. The pile behaviour, when considering the location of the pile tips with regards to the tunnel, has been analysed in great detail by taking the tunnelling-induced pile head settlements, axial pile forces, apparent factor of safety of the piles and shear transfer mechanism into account.

• 디지털융복합연구
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• 제11권11호
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• pp.233-242
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• 2013

기술혁신을 하기 위한 R&D에는 많은 시간과 비용이 투입된다. 따라서 기술혁신을 위해 투자된 연구개발 비용에 대한 전유성을 확보하기 위한 전략이 중요하다. 전유성이란 기술혁신에 대한 수익을 배타적으로 보호 확보할 수 있는 정도를 뜻하며 특허(patent), 영업비밀(secrecy), 리드타임(lead time advantage), 보완적 판매 및 서비스(complementary sales & service), 보완적 제조(complementary manufacturing) 등 5가지의 전유 메커니즘(appropriability mechanism)이 있다. 본 연구에서는 국내 소프트웨어 산업의 전문가들을 대상으로 어떠한 전유성 확보전략을 취하고 있는지에 대하여 설문조사를 하였고, 쌍대비교 기법을 통해 각 요인들의 우선순위를 도출하여 선행연구와 비교하였다. 분석 결과, 국내 IT 제조기업에서는 영업비밀, 특허, 리드타임, 보완적 판매 및 서비스, 보완적 제조의 순으로 전유 메커니즘을 선호하고 있음을 확인하였다.

• 한국가축번식학회지
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• 제20권4호
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• pp.395-412
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• 1997

포유동물의 난자는 제 2 감수분열 중기에서 배란되어 수정된다. 일반적으로 포유동물에서의 수정은 inositol triphosphate (IP3) 또는 cyclic adenosine diphosphoribose (cADPr)에 의해 조절되어지는 세포질내 칼슘변화에 의해 일어난다. 난활성이 일어나면 세포질내 고농도의 MPF (maturation promotion factor)는 감소하고, 전핵이 형성되고, cytoskeleton이 재구성되고, 단백질합성이 조절되어진다. 이러한 모든 과정이 정상적으로 일어난 후 수정란은 종특이한 발달경로로 배발달을 시작한다. 본 논문에서는 돼지난자의 인위적인 난활성 유도방법에 대해서 설명하고자 한다. 신호전달(signal transduction) 경로에 의한 하나의 기전이 돼지난자에서 확인되었는데, 이 경로의 자극은 난활성으로 이루어진다. 또한 전기자극에 의한 난활성방법에 의해 12일까지 정상배 발달이 이루어진다고 보고되고 있다. 향후 연구에서는 정자가 어떠한 기전에 의해서 배발달을 시작하게 하는지를 밝혀내야 한다고 본다.

• The Korean Journal of Physiology and Pharmacology
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• 제12권5호
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• pp.231-236
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• 2008

Heparin is a well-known anticoagulant widely used in various clinical settings. Interestingly, recent studies have indicated that heparin also has anti-inflammatory effects on neuroinflammation-related diseases, such as Alzheimer's disease and meningitis. However, the underlying mechanism of its actions remains unclear. In the present study, we examined the anti-inflammatory mechanism of heparin in cultured cerebral endothelial cells (CECs), and found that heparin inhibited the tumor necrosis factor $\alpha$ ($TNF{\alpha}$)-induced and nuclear factor kappa B (NF-${\kappa}B$)-dependent expression of adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), which are crucial for inflammatory responses. Heparin selectively interfered with NF-${\kappa}B$ DNA-binding activity in the nucleus, which is stimulated by $TNF{\alpha}$. In addition, non-anticoagulant 2,3-O desulfated heparin (ODS) prevented NF-${\kappa}B$ activation by $TNF{\alpha}$, suggesting that the anti-inflammatory mechanism of heparin action in CECs lies in heparin's ability to inhibit the expression of cell adhesion molecules, as opposed to its anticoagulant actions.

• 한국공작기계학회논문집
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• 제13권4호
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• pp.73-78
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• 2004

The conventional SLT(Shear Lag Theory) which has been proven that it can not provide sufficiently accurate strengthening predictions in elastic regime when the fiber aspect ratio is small. This paper is an extented work to improve it by modifying the load transfer mechanism called NSLT(New Shear Lag Theory), which takes into account the stress transfer across the fiber ends and the SCF(Stress Concentration Factor) that exists in the matrix regions near the fiber ends. The key point of the model development is to determine the major controlling factor among the material and geometrical coefficients. It is found that the most affecting factor is the fiber/matrix elastic modulus ratio. It is also found that the proposed model gives a good result that has the capability to correctly predict the elastic properties such as interfacial shear stresses and local stress variations in the small fiber aspect ratio regime.