• 제목/요약/키워드: Heat SinK

검색결과 160건 처리시간 0.028초

("동의수세보원(東醫壽世保元)"에 나타난 사상인(四象人)의 소갈(消渴)에 대한 고찰(考察) (The Bibliographical Study on So-gal of Sasangin)

  • 초재승;임치혜;김효수;김신;김일환;박혜선;이정환
    • 사상체질의학회지
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    • 제19권1호
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    • pp.1-18
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    • 2007
  • 1. Objectives This study is purposed to classify treatment and diagnosis of So-gal on the relationship of Sasang Constitutional Medicine. 2. Methods We compared conception, symptoms, mechanism and treatment of Sasangin's So-gal in ${\ulcorner}$Dongyisusebowon${\lrcorner}$ ${\ulcorner}$Gabobon${\lrcorner}$, ${\ulcorner}$Sinchukbon${\lrcorner}$ and ${\ulcorner}$Chobongwon${\lrcorner}$. 3. Result and Conclusion (1) So-gal of Soyangin is general disease, it is important disease of interior heat syndrome. So-gal of Taeumin is troubled by dryness of the lung, category of interior heat syndrome, but it bring about various complication. So-gal of Soeumin is important point that divide seriousness of disease. (2) So-gal is interior heat syndrome, it is related to interior heat syndrome of Soyangin, Taeumin. So-gal of Soeumin expresses conclusion of seriousness regardless of exterior and interior disease. (3) So-gal is related to nature, it is most important disease to Soyangin who is apt to variation of nature.

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Numerical Analysis on the Flow Characteristics in Steam Ejector

  • Shin, You-Sik;Jin, Zhen-Hua;Chun, You-Sin;Lee, Sang-Chul;Jeong, Hyo-Min;Chung, Han-Shik
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2006년도 하계학술발표대회 논문집
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    • pp.749-754
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    • 2006
  • This study performed of a water cooling system by using a steam ejector and jet condenser to drop the temperature of the water in aquafarm by about $5^{\circ}C$ from $25^{\circ}C$ or higher in this research, to replace the present water cooling system, Ive focused on a water cooling system operated by latent heat of evaporation, thus this system needs a vacuum pressure to evaporate the water in enclosed tank. The water cooling effects are dependent on the vacuum pressure in the enclosed tank, and the cooling water is generated by evaporation. As the experimental results, the absolute vacuum pressure obtained was about $5{\sim}8mmHg$ using a steam driven ejector with jet condenser in experiments. The obtained results are respectively ${\Delta}T=7^{\circ}C$, ${\Delta}T=5^{\circ}C$ and ${\Delta}T=5.5^{\circ}C$ at heat exchanger flow rate 4L/M. The obtained results are respectively ${\Delta}T=5.5^{\circ}C$, ${\Delta}T=5.5^{\circ}C$ and ${\Delta}T=5.5^{\circ}C$ at heat exchanger flow rate 4.5L/M.

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비균일 벽면 온도가 원형 실린더에 충돌하는 고온 제트 유동 및 열전달에 미치는 영향 (Non-uniform wall temperature effect of the flow and heat transfer of a hot circular air jet impinging on a circular cylinder)

  • 홍기혁;강신형
    • 대한기계학회논문집B
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    • 제21권7호
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    • pp.882-890
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    • 1997
  • A buoyant jet flow impinging on a circular cylinder is investigated including heat conduction through the cylinder. Temperature and flow fields are obtained by an iterative method, and the effects of the non-uniform wall temperature on the flow and heat transfer are analyzed. Effects of three-dimensionality and the traversing of the jet are also included. Nusselt number over the cylinder surface for the conjugate case is relatively small as compared with the constant wall temperature case due to the small temperature gradient. As the conductivity of the cylinder becomes lower, Nusselt number decreases due to the reduced temperature gradient. Increasing jet traversing speed causes the surface temperature of the cylinder to decrease, which increases local Nusselt number over the surface.

The Study on the Performance Characteristics of $NH_3$ Refrigeration System using a Shell and Tube Type Heat Exchanger

  • Hong Suck-Ju;Ha Ok-Nam;Kim Jae-Youl;Kwon Il-Wook;Lee Seung-Jae;Jeon Sang-Sin;Jeong Song-Tae;Ha Kyoung-Soo
    • 한국공작기계학회논문집
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    • 제14권4호
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    • pp.69-74
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    • 2005
  • Nowadays CFC and HCFC refrigerants are restricted because they causes to depletion of ozone layer. Accordingly, an experiment is apply to the $NH_3$ gas for refrigerant to study the performance characteristic and to improve the energy efficiency. An experiment are carried out for the condensed pressure in a range from 14.5bar to 16bar and for degree of superheat in a range from 0 to $10^{\circ}C$ at each condensed pressure. As the result of experiment, when degree of superheat is $1^{\circ}C$ and condensed pressure is 14.5bar, the refrigeration system showed the high performance.

진공주조법에 의한 TiNi 형상기억합금 강화 6061Al 지적 복합재료의 계면 및 인장 특성 (Interfacial and Tensile Properties of TiNi Shape Memory Alloy reinforced 6061 Al Smart Composites by vacuum casting)

  • 박광훈;박성기;신순기;박영철;이규창;이준희
    • 한국재료학회지
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    • 제11권12호
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    • pp.1057-1062
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    • 2001
  • We investigated the change of mechanical properties for TiNi shape memory alloy by heat treatment. 6061Al matrix composites with TiNi shape memory alloy as reinforcement were fabricated by vacuum casting. TiNi alloy has the maximum tensile strength at 673K treated and there is no change of tensile strength and hardness at 448K treated. The composites, prepared by vacuum casting, showed good interface bonding by vacuum casting. It was about 3$\mu\textrm{m}$ of thickness of the diffusion layer. Tensile strength of the composite was in higher than that of 6061Al alloy as increased value of about 70MPa at room temperature and about 110MPa at 363K. We thought that the increase of the tensile strength at 363K was due to reverse transformation of the TiNi shape memory alloy.

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Phase Transformation and Mechanical Properties of 14 K White Gold Alloys by Heat Treatments

  • 윤돈규;서진교;안용길;신소라;한동석;박종완
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.283-283
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    • 2013
  • Because of beautiful glossy and color, the value of gold leverage is very high in Europe. To improve the quality of gold alloys, we performed heat treatment on 14 K white gold alloys by variously changing age-hardening conditions. Age-hardening behavior and the related phase transformation changes were studied to elucidate the hardening mechanism of 14 K white gold alloy. For solid solution treatment [ST], casted gold alloy specimens were treated at high temperature ($750^{\circ}C$) for 30 minutes, and the specimens dropped to water to quench them. For Age-hardening treatment [AT], the specimens were treated at various temperatures ($250{\sim}300^{\circ}C$). After the heat treatment, we observed the phenomenon to increase hardness from 126 Hv to 166 Hv by Vicker's hardness tester. Through electron probe micro-analysis (EPMA) mapping analysis, we investigated that irregular particles were changed uniformly. In the SEM and OM images, two phases of matrix and particle-likestructures were observed, and the precipitation of these elements from the matrix progressed during age-hardening. By transmission electron microscope and X-ray diffraction observation, it was revealed that the formation of the Au3Cu superstructure contributed to the age-hardening at $270^{\circ}C$ in the gold alloy. After the heat treatment, this analysis shows that casted gold alloys were to improve hardness and to moderate surface defects at specific temperatures and duration.

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터빈블레이드의 냉각에서 충돌제트에 의해 변화되는 유동 및 열전달 특성에 관한 수치해석적 연구 (A numerical study of flow and heat transfer characteristics varied by impingement jet in turbine blade cooling)

  • 이정희;김신일;유홍선;최영기
    • 대한기계학회논문집B
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    • 제20권12호
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    • pp.4013-4026
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    • 1996
  • A numerical simulation has been carried out for the jet impinging on a flat plate and a semi-circular concave surface. In this computation finite volume method was employed to solve the full Navier-Stokes equation based on a non-orthogonal coordinate with non staggered variable arrangement. The standard k-.epsilon. turbulent model and low Reynolds number k-.epsilon. model(Launder-Sharmar model) with Yap's correction were adapted. The accuracy of the numerical calculations were compared with various experimental data reported in the literature and showed good predictions of centerline velocity decay, wall pressure distribution and skin friction. For the jet impingement on a semi-circular concave surface, potential core length was calculated for two different nozzle(round edged nozzle and rectangular edged nozzle) to consider effects of the nozzle shape. The result showed that round edged nozzle had longer potential core length than rectangular edged nozzle for the same condition. Heat transfer rate along the concave surface with constant heat flux was calculated for various nozzle exit to surface distance(H/B) in the condition of same jet velocity. The maximum local Nusselt number at the stagnation point occurred at H/B = 8 where the centerline turbulent intensity had maximum value. The predicted Nusselt number showed good agreement with the experimental data at the stagnation point. However heat transfer predictions along the downstream were underestimated. This results suggest that the improved turbulence modeling is required.

An Application of Optimum Heat Exchanger for the Grasp on Performance Characteristics of $NH_3$ Refrigeration System

  • 허옥남;권일욱;홍석주;김재열;이종인;전상신;하경수;이승재;박찬수;정송태
    • 한국공작기계학회논문집
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    • 제14권2호
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    • pp.69-74
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    • 2005
  • Since the use of CFC and HCFC refrigerants is to be restricted due to the depletion of ozone layer, this experiment applies the $NH_{3}$ gas to study the performance characteristics from the superheat control for improving the energy efficiency. The experiments are carried out for the condensing pressure of refrigeration system from 1500kPa to 1600kPa by 50kPa and for degree of superheat from $0^{circ}$ to $1^{circ}$ by $10^{circ}$ at each condensing pressure. As a result of experiment, 1) As degree of superheat increased, evaporating pressure of the compressor decreased so equilibrium temperature decreased. And specific volume of refrigerant vapors increased so refrigerant mass flow and heat load of the evaporator decreased. 2) An influence of change of condensing pressure on heat load of the evaporator was insignificant. 3) With the identical degree of superheat, change of compressed temperature was insignificant according to each condensing pressure, so there was little change in enthalpy.4) when the degree of superheat is $0^{circ}$C at each condensing pressure, the refrigeration system has the hi띤est performance.

공기조화, 냉동 분야의 최근 연구 동향: 2006년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006)

  • 한화택;신동신;최창호;이대영;김서영;권용일
    • 설비공학논문집
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    • 제20권6호
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    • pp.427-446
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    • 2008
  • A review on the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006 has been accomplished. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro heat exchanger and siphon cooling device using nano-fluid. Traditional CFD and flow visualization methods were still popular and widely used in research and development. Studies about diffusers and compressors were performed in fluid machinery. Characteristics of flow and heat transfer and piping optimization were studied in piping systems. (2) The papers on heat transfer have been categorized into heat transfer characteristics, heat exchangers, heat pipes, and two-phase heat transfer. The topics on heat transfer characteristics in general include thermal transport in a cryo-chamber, a LCD panel, a dryer, and heat generating electronics. Heat exchangers investigated include pin-tube type, plate type, ventilation air-to-air type, and heat transfer enhancing tubes. The research on a reversible loop heat pipe, the influence of NCG charging mass on heat transport capacity, and the chilling start-up characteristics in a heat pipe were reported. In two-phase heat transfer area, the studies on frost growth, ice slurry formation and liquid spray cooling were presented. The studies on the boiling of R-290 and the application of carbon nanotubes to enhance boiling were noticeable in this research area. (3) Many studies on refrigeration and air conditioning systems were presented on the practical issues of the performance and reliability enhancement. The air conditioning system with multi indoor units caught attention in several research works. The issues on the refrigerant charge and the control algorithm were treated. The systems with alternative refrigerants were also studied. Carbon dioxide, hydrocarbons and their mixtures were considered and the heat transfer correlations were proposed. (4) Due to high oil prices, energy consumption have been attentioned in mechanical building systems. Research works have been reviewed in this field by grouping into the research on heat and cold sources, air conditioning and cleaning research, ventilation and fire research including tunnel ventilation, and piping system research. The papers involve the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies on indoor air quality took a great portion in the field of building environments. Various other subjects such as indoor thermal comfort were also investigated through computer simulation, case study, and field experiment. Studies on energy include not only optimization study and economic analysis of building equipments but also usability of renewable energy in geothermal and solar systems.

견비통(肩臂痛)에 대한 문헌적(文獻的) 고찰(考察) (Consideration of Literatures on the Treatment of Pain in Shoulder and Arm Based on Oriental Medicine)

  • 신홍중;윤일지;오민석
    • 혜화의학회지
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    • 제16권1호
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    • pp.139-146
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    • 2007
  • 1. The etiological causes of Pain in Shoulder and Arm based on literatures of Oriental medicine are attack of wind-heat on the lung, wind cold, damp-heat struggle between the vital energy and pathogenic factor and six pathogenic factors And all these causes are the conception of blockage syndrome, $Q_1$ and blood stagnating in meridian system. 2. Symptoms of Pain in Shoulder and Arm based on literatures of Oriental medicine are shoulder pain, restriction of activity and radiating pain. 3. The treatments of Pain in Shoulder and Arm based on literatures of Oriental medicine are mainly composed of both medical therapy for $B_1$ syndrome due to pathogenic wind, deficiency of both $Q_1$ and blood, consumption of the liver and the spleen, and also acupuncture and moxibustion treatment by selection of acupoint. And those treatments are for treating etiology. And also there are treatments using the meridian system and Twelve Muscle Region and Ashihyeol for the purpose of treating the symptoms. 4. Acupoints such as Gyun-u, Gyun-jung, Goi-ji, Ju-ryo and Bi-no are most used in treating shoulder and arm pain based on based on literatures of Oriental medicine.

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