• Journal of ILASS-Korea
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• v.3 no.3
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• pp.49-59
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• 1998

The vaporization characteristics and spray combustion processes in the high-pressure environment are numerically investigated. This study employ the high-pressure vaporization model together with the state-of-art spray submodels. The present high-pressure vaporization model can account for transient liquid heating, circulation effect inside the droplet forced convection, Stefan flow effect, real gas effect and ambient gas solubility in the liquid droplets. Computations are carried out for the evaporating sprays, the evaporating and burning sprays, and the spray combustion processes of the turbocharged diesel engine. Numerical results indicate that the high-pressure effects are quite crucial for simulating the spray combustion processes including vaporization, spray dynamics, combustion, and pollutant formation.

• Korean Journal of Biological Psychiatry
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• v.13 no.2
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• pp.117-120
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• 2006

Localized amnesia is characterized by a failure to recall events that occurred during a circumscribed period of time. Localized amnesia is the most common type of dissociative amnesia. It is assumed that this is a disorder of memory retrieval. Recent neuroimaing studies reported that posterior cingulate cortex may play a important role in memory(autobiographical) retrieval. The authors reported a case of localized amnesia with mass on left posterior cingulate cortex.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.4 s.235
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• pp.624-631
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• 2005

A note-book PC has become thinner in recent years, which requires the optical disc drives with small height and high memory capacity. Therefore the actuator of optical disc drives must be thinner and have disc tilt compensation function for high density memory. In this paper, the actuator with hybrid type is investigated for 3-axis ultra-slim actuator. A 3-axis ultra-slim actuator is designed by using the modal analysis of the actuator and the electromagnetic analysis of magnetic circuit to achieve dynamic characteristics. Also, magnetic force between tilt magnet and tilt yoke is investigated to and the influence on the DC sensitivity in the focus and track directions.

• Journal of the KSME
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• v.35 no.6
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• pp.542-553
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• 1995

복합열병합 발전 플랜트의 장점은 도시 근교에 발전 플랜트를 간단히 건설할 수 있으며, 공해를 크게 줄이면서 독립적인 발전이 가능하다는 측면에서 신도시, 신공업단지, 도서지방 등에서 아주 유리한 것으로 알려져 있다. 또한 가스 터빈 배기열을 이용하여 대규모 주거 지역이나 공업 단 지내에서 필요한 난\ulcorner냉방열이나 공업열원으로의 활용이 손쉬우며, 주변 시설이 복잡하지 않고, 개선된 연소기술에 의하여 공해를 크게 줄일 수 있다. 최근 들어 분당\ulcorner일산\ulcorner부천 지역 등에 열병합 플랜트가 건설되고 있으나 거의 모든 설계기술은 외국 기술에 의존되고 있으며, 국산화 율도 극히 저조하여 '93년도에 완공된 부천 화력(473MW)의 경우 약 30% 정도이다. 복합열병합 발전 시스템은 가스 터빈, 스팀 터빈 등의 터보기계 기술을 근간으로 하며, 열회수장치 및 열교 환장치의 설계기술, 각종 제어기술 등의 종합 설계기술로서 이미 선진국에서는 실용화된지 오 래되었으며 우리 나라에도 여러 종류의 플랜트가 도입되어 사용되고 있다.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.1
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• pp.137-146
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• 2008

Nd:YAG pulse laser welding of stainless steel plate was simulated to find welding condition by using commercial finite element code MARC. Due to geometric symmetry, a half model of AISI 304 stainless steel plate was considered and user subroutines were applied to boundary condition for the heat transfer. Material properties such as conductivity, specific heat, mass density and latent heat were given as a function of temperature. As results, Three dimensional heat source model for pulse laser beam conditions of butt welding has been designed by the comparison between the finite element analysis results and experimental data on AISI 304 stainless steel plate. Nd:YAG laser welding for AISI 304 stainless steel was successfully simulated and it should be useful to determine optimal welding condition.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.273-278
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• 2003

Recently, high-performance hybrid composite materials have been used for various industrial fields because of their superior high strength, high stiffness and lower weight. In this study, manufactured hybrid composite materials are composed of two parts. One is hard-anodized Al5083-O alloy as a face material and the other is high strength aramid fiber ($Twaron^{(R)}$ CT709) laminates as a back-up material. Resistance to penetration is determined by protection ballistic limit($V_{50}$, a static velocity with 50% probability for complete penetration) test method. $V_{50}$ tests with $0^{\circ}$obliquity at room temperature were conducted with 5.56mm ball projectiles that were able to achieve near or complete penetration during high velocity impact tests.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.267-272
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• 2003

In order to investigate the effect of face material on Ti/Al alloy laminates under high velocity impact, a ballistic testing was conducted. Ballistic resistance of these materials was measured by protection ballistic limit($V_{50}$), a statistical velocity with 50% probability penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, were respectfully observed, by $V_{50}$ test and Projectile Through Plates (PTP) test at velocities greater than $V_{50}$. PTP tests were conducted with $0^{\circ}$obliquity at room temperature using 5.56mm ball projectile. $V_{50}$ tests with $0^{\circ}$obliquity were also done with projectiles that were able to achieve near or complete penetration during PTP tests. Resistance to penetration, and penetration modes which face material was Titanium alloy, were compared to those which face material was anodized Al alloy after cold-rolling.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1485-1490
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• 2003

This paper is the analysis of thermal and fluid in solar concentration absorber with various tilt angle and opening ratio of absorber entrance. The purpose of this study is to develop optimum solar concentration absorber, and the parameters for the study are the opening ratio of absorber entrance and the tilt angle. The aspect ratio of absorber was fixed at 0.64, and opening ratio was changed from 0.1 to 1.0. The finite volume method with SIMPLE computational algorithm are used and analyzed the heat transfer in absorber inside walls.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.3
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• pp.170-177
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• 2009

In the present study, a finite element analysis of conjugate heat transfer problem inside a cavity with a heat-generating conducting body, where constant heat flux is generated, is conducted. A conduction heat transfer problem inside the solid body is automatically coupled with natural convection inside the cavity by using a finite element formulation. A finite element formulation based on SIMPLE type algorithm is adopted for the solution of the incompressible Navier-Stokes equations coupled with energy equation. The proposed algorithm is verified by solving the benchmark problem of conjugate heat transfer inside a cavity having a centered body. Then a conjugate natural heat transfer problem inside a cavity having a heat-generating conducting body with constant heat flux is solved and the effect of the Rayleigh number on the heat transfer characteristics inside a cavity is investigated.

• Clinical and Experimental Pediatrics
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• v.51 no.9
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• pp.1018-1022
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• 2008

Testicular adrenal rest tumors are a well-known complication in male patients with congenital adrenal hyperplasia. Corticosteroid suppressive therapy usually results in the regression of these tumors. We describe a patient with 21-hydroxylase deficiency who developed bilateral testicular masses. Despite steroid suppressive therapy, the tumors did not regress and hormonal control was poor. Consequently, bilateral partial orchiectomies were performed.