• Journal of computational fluids engineering
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• v.11 no.3 s.34
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• pp.64-70
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• 2006

A Computational study was carried out in order to investigate the moving wall effect of a circular cylinder at a Reynolds number of $2.0{\times}10^4$. The viscous-incompressible Navier-Stokes equations and Spalart-Almaras turbulent model of the commercial CFD code were adopted for this numerical analysis. The moving wall was set parallel with the freestream, and moving speed was equal to the freestream velocity. The gap ratio is defined as the distance ratio between the circular cylinder diameter and the height from the moving wall. The results show that there is vortex shedding over the critical gap ratio and aerodynamic loads including amplitude and the Strouhal number change according to the gap ratio.

• Journal of Environmental Science International
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• v.9 no.5
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• pp.403-408
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• 2000

On the basis of theory of Bratsch's electronegativity equalization the electronegativity equalization the group electronegativities and the group partial charges for cationic and amphoteric surface and amphoteric surfactants could be calculated using Pauling's electronegativity parameters. From calculated output we have investigated relationships between CMC(critical micelle concentration) and partial charge and group electronegativity of hydrophilic and hydrophobic groups structural stability of micelle for cationic and amphoteric surfactants. As a result CMC depends upon partial charge and electronegativity of hydrophilic group is decreased. With increasing the carbon number of hydrophilic group for cationic surfactant its partial charge is increased but CMC and its electronegativity are decreased. With increasing the carbon number of hydrophobic group for cationic and amphoteric surfactant its partial charge is increased but CMC andits electronegativity are decreased.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.6
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• pp.121-131
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• 2012

Many of the falling which is the number one risk factor in lethal accidents in construction could have been prevented if the right activity or supervising had been taken in time. All other measures do not preventive the fall, but rather intercept the fallen itself or preventive severe injury. The most common and the bets measures on the preventive measures are guardrails which are to be worn on the site. Workers always exposed the risk of serious accidents induced by causal effects related with environments around construction sites. In order to represent how to decrease the risk of workers, this study was accomplished with a number of interview with experienced site director, cheief of instructors, workers. And the questionaire survey (2012. 5~2012. 10) were used to make proposed policies which are expected to reduce critical disastrous accidents and strength authorized limits of director's management automatically.

• 열병합발전
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• s.36
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• pp.16-21
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• 2003

For many years, T/G Supplier has constructed a number of thermal power plants and researched to improve the performance and the reliability of steam turbine, which are achieved by advances in design and materials technology. In recent, interest is renewed in advance steam condition as means of improving economy of thermal power plant and reducing environmental pollution. Improvements in the maximum power have been driven by the development of advanced rotor and bucket material and longer last stage bucket. Improvements in efficiency have been brought through advance in mechanical efficiency and thermodynamic efficiency. This paper describes a number of new steam path design features introduced to the steam turbine product. And also this paper describes new design technologies' development, new technologies' trend and technologies' development for ultra-super critical steam turbine.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2174-2179
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• 2003

For many years, T/G Supplier has constructed a number of thermal power plants and researched to improve the performance and the reliability of steam turbine, which are achieved by advances in design and materials technology. In recent, interest is renewed in advanced steam condition as means of improving economy of thermal power plant and reducing environmental pollution. Improvements in the maximum power have been driven by the development of advanced rotor and bucket material and longer last stage bucket. Improvements in efficiency have been brought through advances in mechanical efficiency and thermodynamic efficiency. This paper describes a number of new steam path design features introduced to the steam turbine product. And also this paper describes new design technologies' development, new technologies' trend and technologies' development for ultra-super critical steam turbine.

• Journal of Korean Critical Care Nursing
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• v.4 no.1
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• pp.25-35
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• 2011

Purpose: The purpose of this study was to evaluate the actual outcomes of early discharge program for extremely low birth weight (ELBW) infants. Methods: Medical records of 122 ELBW infants admitted in the neonatal intensive care unit from January 2000 to June 2006 and those of their 112 mothers were analyzed retrospectively. Results: After being applied early discharge program to ELBW infants' mothers, their infants' lengths of stay, gestational age and body weight at discharge, duration of completion of oral feeding, number of emergency room visits after discharge were decreased and number of breast milk feeding was increased. Conclusion: Early discharge program for ELBW infants can be an effective intervention for parents and their ELBW infants contributing to neonatal nursing practices.

• International Journal of Contents
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• v.8 no.4
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• pp.1-6
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• 2012

Mutual Exclusion is one of the most studied topics in distributed systems where processes communicate by asynchronous message passing. It is often necessary for multiple processes at different sites to access a shared resource or data called a critical section (CS) in distributed systems. A number of algorithms have been proposed to solve the mutual exclusion problem in distributed systems. In this paper, we propose the new algorithm which is modified from Garg's algorithm[1] thus works properly in a fault-tolerant system. In our algorithm, after electing the token generator, the elected process generates a new token based on the information of the myreqlist which is kept by every process and the reqdone which is received during election. Consequently, proposed algorithm tolerates any number of process failures and also does even when only one process is alive.

• Korean Journal of Mathematics
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• v.22 no.4
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• pp.633-644
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• 2014

We get one theorem that there exists a unique solution for the fourth order semilinear elliptic Dirichlet boundary value problem when the number 0 and the coefficient of the semilinear part belong to the same open interval made by two successive eigenvalues of the fourth order elliptic eigenvalue problem. We prove this result by the contraction mapping principle. We also get another theorem that there exist at least two solutions when there exist n eigenvalues of the fourth order elliptic eigenvalue problem between the coefficient of the semilinear part and the number 0. We prove this result by the critical point theory and the variation of linking method.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.544-549
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• 2014

임계마하수보다 큰 자유흐름 마하수에서는 충격파의 발생으로 인해 급격한 항력증가가 발생하므로, 임계마하수 증가는 고속 공기역학에서 중요한 분야로 다뤄지고 있다. Whitcomb R. T.에 의해 천음속영역에서 순항할 수 있는 초임계익형이 개발되었으나, 충격파 제어 기법들에 대한 실험적인 검증은 형상 제작의 어려움으로 인해 한계를 지닌다. 따라서 본 논문에서는 2D_Comp-2.1_P와 Prandtl-Glauert 압축성 보정식을 이용하여 NACA0012와 RAE2822의 임계마하수를 해석하고, 충격파 제어 장치 중 하나인 Bump를 RAE2822에 설치하여 임계마하수를 향상시키기 위한 연구를 수행하였다. 연구 결과 충격파를 압축파로 분산시켜 충격파의 강도를 약화시키고, 양항비의 4.7% 증가를 확인하였다. 따라서 Bump를 설계한 RAE2822가 기본 익형보다 높은 천음속 조건에서 효율적인 공력특성을 가지는 것을 확인하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.8
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• pp.718-723
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• 2000

The critical characteristics of Bi-2223 HTS tapes made by PIT method are influenced by the heat treatment and the mechanical processing. In this study firstly we investigated the influence o rolling reduction rate in mechanical process for improving Jc of HTS tapes. As a result the optimized rolling reduction rate that we obtained was 10%-50% and 30%-30% (1st-2nd). And then we fabricated the stacking type HTS tapes that made of the multi-filamentary tapes with various length(3, 5, 10cm) and with various number of stacking (1, 5, 10 layer). Measuring the critical current and observing the structure of grain we concluded that the stacking type tapes will be able to operate more stably by adding the number of stacking tapes. And we could expect that by minimizing the gap between Ag-sheath of tapes mechanical strength of stacking HTS tapes is enhanced and current in tapes will flow more stably.