• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.5
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• pp.455-461
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• 2015

A high-pressure fuel pump is a key component in a gasoline direct injection (GDI) engine; thus, understanding its flow characteristics is essential for improving the engine power and fuel efficiency. In this study, AMESim, which is a hydraulic analysis program, was used to analyze the performance of the high-pressure fuel pump. However, since AMESim uses a one-dimensional model for the system analysis, it does not accurately analyze the complicated flow characteristics. Thus, Fluent, computational fluid dynamics (CFD) software, was used to calculate the flow rates and net forces at the intake and discharge ports of the high-pressure fuel pump where turbulent flow occurs. The CFD analysis results for various pressure conditions and valve lifts were used as look-up tables for the AMEsim model. The CFD analysis results complemented the AMEsim results, and thus, improved the accuracy of the performance analysis results for the high-pressure fuel pump.

• The Safety technology
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• no.155
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• pp.18-19
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• 2010

(주)고산(1996년 제일공조부품(주)에서 상호변경)은 국내외에서 알아주는 자동차 및 가전기기 부품 생산업체다. 국내외 대형 공조기 업체들의 협력시인 이곳은 국내 5대 자동차 회사는 물론 해외 주요 자동차 회사에 자동차용 Radiator, Condenser, Cooling module을 생산 납품하고 있다. 또한 국내 2대 가전회사에는 에어컨 Condenser를 생산해 공급하고 있다. 1988년 설립이후 꾸준한 기술개발과 판로 개척을 해 온 이곳은 그간 성장에 성장을 거듭 현재는 미국 중국 등지에 8개의 법인을 가진 중견기업으로 우뚝 섰다. 실제 지난해 매출만도 1,455억원(해외법인 포함)에 달할 정도이다. 이처럼 업력 20년을 갓 넘긴 기업이 알짜기업으로 거듭날 수 있었던 이유는 무엇일까? 이에 대해 이곳의 임직원들은 철저한 안전관리를 일순위로 꼽는다. '사고 없는 안전한 작업환경'과 '건강한 근로자라는 인프라가 회사의 성장을 이끌고 있다는 것 이런 우수한 환경이 조성된 데에는 안전 환경 등의 업무를 맡고 있는 경영지원팀의 힘이 크다. 특히 그중에서도 일등공신은 팀을 이끌고 있는 장혁 팀장이라 할 수 있다. 일반시설안전관리자 방화관리 1급 등 다양한 환경안전분야 자격증을 가지고 있는 그는 전문가로서의 폭넓은 지식과 풍부한 경험을 바탕으로 회사의 안전을 선두에서 진두지휘하고 있다 안전을 통해 회사의 청사진을 그려내고 있는 그를 만나봤다.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.1-11
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• 2002

A mathematical model is proposed to analyze the force; acting on the hard contact lens fitted on the cornea. The model incorporates the nonlinear equations and their numerical solution program, based on the formulations of surface tension force arising from the capillary action in the tear-film layer between the lens and cornea. The model simulates how the adhesion between lens and cornea varies according to the base curves and diameters of the lenses. When the spherical lens is fitted on the spherical cornea it is to rotate downward due to the weight of lens itself until it reaches an equilibrium position along the cornea where the counter(upward) moment caused by net force between the upper and lower portion of the periphery of lens. It is found that both the adhesion and displacement of lens along the cornea, where the gravity of lens balances the capillary-induced upward force, increases rapidly as the base curve of lens increases, i.e., as the lens gets flatter, while the increase in the diameter of lenses has resulted in the less increase in the rotation and adhesion. With the base curve and diameters of lenses being remained constant the increase in surface tension of tear film yields the increase in the adhesion between the cornea and lens while the initial rotation of lens is inversely proportional to the surface tension of the tear film.

• New Physics: Sae Mulli
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• v.68 no.12
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• pp.1293-1301
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• 2018

The basic magnetic properties of commercially available High-$T_c$ Superconductor (HTS) GdBCO-coated conductor (GdBCO-CCs) were investigated by using physical property measurement system-vibrating sample magnetometer (PPMS-VSM). From the zero-field-cooled (ZFC) m(T) curve, the $T_c$ was found to be ~93 K. After removing the background m(H) data, we obtained both the net m(H) data and the ${\Delta}m_{irr}$. The $H_{irr}(T)$ coincided very well with the power-law relation $H_{irr}=H_{irr}(0)(1-T/T_c)^n$ with $$n{\sim_=}1.19$$. The magnetic flux behavior was investigated by using the ${\delta}$ values in the relationship $J_c{\propto}{\Delta}m_{irr}{\propto}H^{-{\delta}}$. A ${\delta}{\approx}0$ region denoting an independent magnetic flux pinning effect, a ${\delta}{\approx}0.6{\sim}1.2$ region representing a collective flux pinning effect due to the interaction, and a ${\delta}{\gg}2$ region representing freely moving magnetic fluxes caused by the Lorentz force were observed. The boundary line between ${\delta}{\approx}0$ and ${\delta}{\approx}0.6{\sim}1.2$ is denoted by a $H_1$, and the one between ${\delta}{\approx}0.6{\sim}1.2$ and ${\delta}{\gg}2$ is denoted by a $H_2$. The ${\delta}(T)$ was obtained in the region of $H_1$ < H < $H_2$. As the temperature was decreased, the ${\delta}$ value gradually decreased.