• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.463-467
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• 2015

Mega-shock means a sporadic event such as the earning shock, which occurred by sudden market changes, and it can cause serious problems of profit loss of international construction projects. Therefore, the early response and prevention by analyzing and predicting the Mega-shock is critical for successful project delivery. This research is preliminary study to develop a prediction model that supports market condition analysis and Mega-shock forecasting. To avoid disadvantages of classic statistical approaches that assume the market factors are linear and independent and thus have limitations to explain complex interrelationship among a range of international market factors, the research team explored the Fractal Theory that can explain self-similarity and recursiveness of construction market changes. The research first found out correlation of the major market factors by statistically analyzing time-series data. The research then conducted a base of the Fractal analysis to distinguish features of fractal from data. The outcome will have potential to contribute to building up a foundation of the early shock warning system for the strategic international project management.

• Bulletin of the Korean Chemical Society
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• 제7권4호
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• pp.293-296
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• 1986

The Hugoniot adiabatics and viscosity of shock compressed water have been calculated by applying the significant structure theory of water. To consider the effects of pressure and temperature, the sublimation energy has been expressed by the spherically averaged Stillinger-Rahman ST2 potential. Good agreements between theory and experiment are obtained in the whole extreme ranges of shock wave condition up to 100 GPa (lMbar).

• 천문학회보
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• 제39권1호
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• pp.37.2-37.2
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• 2014

Gas in disk galaxies interacts nonlinearly with a underlying stellar spiral potential to form galactic spiral shocks. Numerical simulations typically show that these shocks are unstable to the wiggle instability, forming non-axisymmetric structures with high vorticity. While previous studies suggested that the wiggle instability may arise from the Kelvin-Helmholtz instability or orbit crowding of gas elements near the shock, its physical nature remains uncertain. It was even argued that the wiggle instability is of numerical origin, caused by the inability of a numerical code to resolve a shock that is inclined to numerical grids. In this work, we perform a normal-mode linear stability analysis of galactic spiral shocks as a boundary-value problem. We find that the wiggle instability originates physically from the potential vorticity generation at a distorted shock front. As the gas follows galaxy rotation, it periodically passes through multiple shocks, successively increasing its potential vorticity. This sets up a normal-mode that grows exponentially, with a growth rate comparable to the orbital angular frequency. We show that the results of our linear stability analysis are in good agreement with the those of local hydrodynamic simulations of the wiggle instability.

• International Journal of Fluid Machinery and Systems
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• 제9권4호
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• pp.362-369
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• 2016

The shock-free inflow criterion applied in the development of two-dimensional cascade for turbomachinery design. The developed cascade analysis with potential flow calculation through a panel method has been used to determine the shock-free inflow condition. The combination between cascade analysis and PSO (particle swarm optimization) algorithm provides an opportunity to develop a diagram of a two-dimensional parameter cascade at various airfoil shapes. Analytical equations have been derived from the diagram that will facilitate the turbomachinery designer in applying the shock-free inflow criterion on their developed cascade. This method has been used to develop the very low head axial hydraulic turbine and provides excellent results of numerical and actual prototype performances.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.251-255
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• 2015

Unsteady Shock-Induced Combustion has been studied for the past few decades since it is considered as one of the potential ways to reach supersonic flights. Experimental observations of Unsteady SIC were observed as early as 1960's. But Lehr was the first to report in detail the mechanisms of Shock-Induced Combustion experimentally. Numerical Studies on SIC were helpful in explaining the insight into the oscillatory behaviour in the mid 90's to early 2000's. Detailed reaction mechanisms is required to prediction the SIC flowfield more in detail. However at that time, very few reaction mechanisms on hydrogen-oxidation were reported. In the last decade, various number of hydrogen reaction mechanisms were reported. In this study, an attempt has been made to analyze the effect of various reaction mechanisms in an unsteady mode of Shock-Induced Combustion.

• 조명전기설비학회논문지
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• 제21권1호
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• pp.142-147
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• 2007

본 논문은 대지구조와 접지봉의 매설깊이에 따른 대지표면의 전위상승에 대해서 기술하였다. 대지표면의 전위상승에 따른 인체의 감전사고의 저감에 관한 기초적 자료를 제안하기 위해서 접지봉 부근에서의 대지표면전위를 계산하고 측정하였다. 접지봉 부근의 대지표면전위상승은 대지구조에 크게 의존하며, 매설깊이가 깊어질수록 낮아졌다. 대지표면전위상승은 접지봉의 직상부에서 최대이었으며, 측정결과는 접지해석프로그램으로 계산한 결과와 잘 일치하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1453-1454
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• 2007

A street light is an electrical equipment to improve the traffic safety and the security for people in night. However, many accidents due to electric shock have happened in recent, people were interested in the safety of electrical facilities. And people want to know the danger by touch and step voltages. When the electric power lines fall down on the ground, the fault current flows to ground rod and the potential near the ground rod is increased to induce the high touch and step voltages. In this paper, we installed different ground rods with a street light and investigated the electrical potential according to ground methods and the types of ground rod. Finally, we examined the electrical facilities with the experimental result and present the improved technical data for the safety from electric shock

• 한국식품영양학회지
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• 제28권3호
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• pp.343-350
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• 2015

Lonicera japonica 에탄올 추출물의 처리에 의하여 LPS에 의해서 활성화된 RAW 264.7 세포에서 NO의 생성량과 TNF-${\alpha}$, IL-$1{\beta}$ 및 IL-6와 같은 염증성 사이토카인의 분비를 억제하였고, MAPK family인 ERK, p38 및 JNK의 인산화와 $I{\kappa}-B{\alpha}$의 분해를 억제하였다. LPS로 유도한 endotoxin shock 동물실험에서 Lonicera japonica 에탄올 추출물 20 mg/kg에서 LPS로 유도한 endotoxin shock에 대한 생존율을 3배 이상 증가시켰으며, 생존시간도 1.3~1.4배 증가시켰다.

• 조명전기설비학회논문지
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• 제25권6호
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• pp.68-74
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• 2011

The touch or step voltages which exist in the vicinity of a grounding electrode are closely related to the earth structure and resistivity and the ground current. The grounding design approach is required to determine the grounding electrode location where the hazardous voltages are minimized. In this paper, in order to propose a method of mitigating the electric shock hazards caused by the ground surface potential rise in the vicinity of a counterpoise, the hazards relevant to touch voltage were evaluated as a function of the soil resistivity ratio $\rho_2/\rho_1$ for several practical values of two-layer earth structures. The touch voltage and current on the ground surface just above the test electrode are calculated with CDEGS program. As a consequence, it was found that burying a grounding electrode in the soil with low resistivity is effective to reduce the electric shock hazards. In the case that the bottom layer soil where a counterpoise is buried has lower resistivity than the upper layer soil, when the upper layer soil resistivity is increased, the surface potential is slightly raised, but the current through the human body is reduced with increasing the upper layer soil resistivity because of the greater contact resistance between the earth surface and the feet. The electric shock hazard in the vicinity of grounding electrodes is closely related to soil structure and resistivity and are reduced with increasing the ration of the upper layer resistivity to the bottom layer resistivity in two-layer soil.

• BMB Reports
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• 제38권6호
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• pp.695-702
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• 2005

The groESL bicistronic operon of a restricted facultative methylotrophic bacterium Methylovorus sp. strain SS1 DSM 11726 was cloned and characterized. It was found to consist of two ORFs encoding proteins with molecular masses of 11,395 and 57,396 daltons, which showed a high degree of homology to other bacterial GroES and GroEL proteins. The genes were clustered in the transcription order groES-groEL. Northern blot analyses suggested that the groESL operon is transcribed as a bicistronic 2.2-kb mRNA, the steady-state level of which was markedly increased by temperature elevation. Primer extension analysis demonstrated one potential transcription start site preceding the groESL operon, which is located 100bp upstream of the groES start codon. The transcription start site was preceded by a putative promoter region highly homologous to the consensus sequences of Escherichia coli ${\sigma}^{32}$-type heat shock promoter, which functioned under both normal and heat shock conditions in E. coli. Heat shock mRNA was maximally produced by Methylovorus sp. strain SS1 approximately 10min after increasing the temperature from 30 to $42^{\circ}C$. The groESL operon was also induced by hydrogen peroxide or salt shock.