• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.311-315
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• 2012

Diaphragm type noncontact automatic control valve is a valve for controling acidic PR(Photo Resist) liquid used in the semiconductor process. PR is photosensitive liquid that changes phases depending on light transmittance. PR is very toxic and expensive; the purpose of this paper is to address methods that prevent loss due to leaks. The design of noncontact precise automatic control valve is expected to play an important role in controlling fluid flow, therefore influencing energy conservation and environmental improvement. In this paper, diaphragm type automatic control valve's part design, assembly and simulation are introduced. Also, through the analysis of fluid flow the valve's internal velocity, pressure, and turbulent intensity are interpreted. This paper proposes to contribute to the improvement of the valve's performance.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.196-201
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• 2012

This study represents numerical study on the thermal and fluid flow characteristics of exhaust gas in a motorcycle muffler. The engine generates 125cc of displacement. Numerical analysis with computational fluid dynamics(CFD) was carried out to investigate the exhaust gas that flow into a motorcycle muffler. The STAR-CD S/W used to analyze three dimensional steady state and transient in a muffler. The Navier-Stokes Equation is solved with SAMPLE and PISO method in cartesian coordinates system. As the numerical result, it could be confirmed pulsating pressure generated from inlet of muffler become closer to the atmospheric pressure through baffle. Also the numerical result was almost identical to experimental result and, through the comparison, the reliability of numerical result was confirmed.

• Journal of Sensor Science and Technology
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• v.22 no.3
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• pp.227-232
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• 2013

In this research, fiber-optic pressure sensors were fabricated with rugate-structured porous silicon (RPS) diaphragms coated with PMMA (Polymethyl-Methacrylate). The reflectance spectrum of the PMMA/RPS diaphragm was almost the same as that of uncoated RPS diaphragm. However the mechanical strength of the PMMA/RPS diaphragm increased more than that of the uncoated diaphragm. As a result, the fiber-optic sensor fabricated with PMMA/RPS diaphragm could successfully detect more high pressure difference without diaphragm damage than the highest detectable pressure difference of the sensor with normal RPS diaphragm. The response data of the fiber-optic sensor recorded as a function of pressure difference were fitted by theoretical curves. During this process, elastic moduli of the used PMMA/RPS diaphragms were obtained numerically. The dynamic response properties of the fiber-optic sensor were also investigated under continuous variation of the pressure difference conditions.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.92-96
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• 2007

Internal flow characteristics for an automobile HVAC have been investigated using a high-resolution PIV technique. The PIV system consists of a 2-head Nd:YAG laser(125 mJ), a high-resolution CCD camera($2K\;{\times}\;2K$), optics and a synchronizer. An automobile HVAC module was used directly. Only the casing was remodeled transparently for capturing flow image and laser sheet beam illumination. Time-averaged velocity field were measured in three temperature control mode. For three temperature control modes, the internal flow characteristics for an automobile HVAC system were evaluated from PIV results..

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.687-688
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• 2008

Air flow of inside automobile HVAC module has been visualized using a high-resolution PIV technique with varying the temperature operation mode. The PIV system consists of a 2-head Nd:YAG laser(125 mJ), a high-resolution CCD camera(2K x 2K), optics and a synchronizer. A real automobile HVAC module was used directly with slight modification for clear optical windows. Some parts of the HVAC module casing were replaced with transparent windows for capturing flow images with laser light sheet beam illumination. Time-averaged velocity field were measured in three temperature control modes. Flow characteristics of the air-conditioned air flow in the automobile HVAC system were evaluated.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.157-162
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• 2003

This study is analysis on the heat transfer of exhaust gas into the muffler at passenger Car. Numerical analysis with Computational fluid Dynamics(CFD) was carried out to investigate exhaust gas flow. The STAR-CD S/W used for the three dimensional steady state CFD analysis in a muffler. The Navier-Stokes Equation is solved with the SIMPLE method in a general cartesian coordinates system. Result of numerical simulation; Inlet and outlet temperature shown about ${\Delta}T=239K$, 216K, 202K at in the muffler. Heat transfer was progressed quickly by atmospheric temperature of muffler external at in the near wall.

• Solar Energy
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• v.8 no.2
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• pp.66-72
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• 1988

Natural convection in a horizontal annulus with spacers has been studied on the effects of diameter ratio and Rayleigh numbers and position of spacers by experimental method. In case of vertical spacers, the local spacer Nusselt numbers show positive values on the lower spacer, but negative values on the upper spacer. In case of horizontal spacers, the local spacer Nusselt numbers show positive values on the upward surface of spacer, but negative values on the downward surface of spacer. The mean tube Nusselt numbers and mean cylinder Nusselt numbers with vertical spacer are increased 10% and 2.1%, respectively by those of horizontal spacer.

• Solar Energy
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• v.2 no.1
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• pp.1-8
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• 1982

A theoretical study by numerical method has been performed on the natural convection of an air contained in enclosures. The enclosures have rectangular cross section with one vertical wall heated and the other cooled, and with two horizontal partition plates of finite thermal conductivity. Steady two-dimensional flow was assumed. The computation was executed by means of the Implicit Alternating Direction (I.A.D) finite-difference method. Two partition plates of Aluminium whose thickness were 0.05mm was employed in computation. Isothemals, streamlines, local Nusselt numbers and mean Nusselt numbers were obtained for various Grashof numbers and aspect ratio and these results were compared with those in the case of the enclosure with two horizontal insulated plates. From the present results, the heat transfer in the case of partition plates was greater than that in the case of insulation. This study suggests a method to measure the overall heat-transfer of coefficient in double walls which supported by partition plates for insulative construction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.310-317
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• 2002

In the present study, an experimental study of natural convection in a partitioned 2D square enclosure has been carried out. The square enclosure consist of two adiabatic vertical walls and the upper cold and the lower hot walls. A partition is positioned perpendicularly at the center of the left vortical insulated wall. The PIV measurements were performed with the variations of Rayleigh number, partition length and inclination of the enclosure. The working fluid is water with Prandtl number of 6.996 at 20$\^{C}$. The captured images were analyzed by using a cross-correlation (two-frame/single-exposure) PIV method.

• The Korean Journal of Malacology
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• v.11 no.1
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• pp.1-20
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• 1995

1993년 7월부터 1994년 5월까지 제주도 차귀도 4개 지점 조간대의 대형저서무척추동물의 분포와 군집구조에 관한 연구결과는 다음과 같다. 1. 차귀도 조간대에 분포하는 대형무척추동물은 총 9문, 17강, 35목, 75과, 146종이었다.2. 계절별 출현종수는 춘계에 124종, 하계 113종, 추계 99종, 동계에 86종이었다.3. 조간대 상부구역의 제1우점종은 좁쌀무늬총알고둥(N. exigua), 제2우점은 거북선(P. mitalla). (N.japonica),울타리고둥(M. labio), 중부구역은 배무래기(N. schrenkii), 밤고둥(C. argyrostoma lischkei), 울타리고둥, 깜장각시고둥(M. perplexa), 검은따개비(T. squamosa japonica)가 지점에 따라 제1, 제2우점종을 이루었다. 하부구역은 밤고둥, 검은따개비, 줄군부 (L. coreanica), 거북손, 굵은줄격판담치(S. virgatus)가 지점에 따라 우점하였으며, 상부구역 우점종의 군집우점지수는 매우 높았다.4. 조간대 하부구역의 종다양성은 상부구역이나 중부구역에 비하여 컸고 계절별 출현종수에 유의성이 있었으나 상부구역이나 중부구역에는 없었다.5. 종다양도지수와 균등도에는 상. 중. 하 구역별유의성은 없었고 풍부도에서는 상부구역에서 유의하였다.6. 제주 미기록종으로 부채넓적이끼벌레(D. su-bovoidea), 딱지조개(P. japonica), 목주림고둥(T. guerinii), 전촉수갯지렁이(A. validus), 바다거미(L. hilgendorfi)가 채집되었다.