• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.4
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• pp.315-323
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• 2002

The commercial viability of heat exchanger is mainly dependent on their long-term fouling characteristics because the fouling increases the pressure loss and degrades the thermal performance of a heat exchanger. An experimental study was performed to investigate the characteristics of fluid flow and heat transfer in a fluidized bed heat exchanger with circulating various solid particles. The present work showed that the drag force coefficients of particles in the internal flow were higher than those in the external flow, in addition, the solid particle periodically hitting the tube wall broke the thermal boundary layer, and increased the rate of heat transfer. Particularly when the flow velocity was low, the effect was more pronounced.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2039-2042
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• 2008

Recently, Electronic & Electrical Products have problems how to reduce heat in trend reducing size and increasing speed. heat pipes worked by latent heats can solve problems for effective and quiet electronic applications. Heat Pipes have to be suitably designed for the external conditions due to showing optimum performance. it has influence on efficiency of heat pipes to the exterior structure changed by length, bending angle, diameter. Designing heat pipes has depended on experience from trial and error. this method wasted too many resources, but can't guarantee efficiency. to prevent those wastes, this study aims at making the thermal transfer coefficient predicting efficiency. In this study, the thermal transfer coefficient has been made from experimental results that used variables - lengths between heat source and radiation, bending angles, diameters of heat pipes. variables become non-dimensional in modeling process for making the coefficient.

• Current Photovoltaic Research
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• v.6 no.2
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• pp.39-42
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• 2018

When the PV module is illuminated in a high temperature region, solar cells are also exposed to the high temperature external environment. The operating temperature of the solar cell inside the module is increased, which causes the power drops. Various efforts have been made to reduce the operating temperature and compensate the power of solar cells according to the outdoor temperature such as installing of a cooling system. Researches have been also reported to lower the operating temperature of solar cells by improving the heat dissipation properties of the backsheet. In this study, we conducted a test to measure the internal temperature of each module components and the external temperature when the light was irradiated according to the surrounding temperature. Backsheets with different thermal conductivities were compared in the test. Finally, in order to explain the temperature difference between the solar cell and the outside of the module, we proposed an evaluation method of the heat transfer characteristics of photovoltaic modules with different backsheet.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.273-275
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• 2005

Active thermography is being used since several years for remote non-destructive testing. It provides thermal images for remote detection and imaging of damages. Also, it is based on propagation and reflection of thermal waves which are launched from the surface into the inspected component by absorption of modulated radiation. For energy deposition, it use external heat sources (e.g., halogen lamp or convective heating) or internal heat generation (e.g., microwaves, eddy current, or elastic wave). Among the external heat sources, the ultrasound is generally used for energy deposition because of defect selective heating up. The heat source generating a thermal wave is provided by the defect itself due to the attenuation of amplitude modulated ultrasound. A defect causes locally enhanced losses and consequently selective heating up. Therefore amplitude modulation of the injected ultrasonic wave turns a defect into a thermal wave transmitter whose signal is detected at the surface by thermal infrared camera. This way ultrasound thermography(UT) allows for selective defect detection which enhances the probability of defect detection in the presence of complicated intact structures. In this paper the applicability of UT for fast defect detection is described. Examples are presented showing the detection of defects in PCB material. Measurements were performed on various kinds of typical defects in PCB materials (both Cu metal and non-metal epoxy). The obtained thermal image reveals area of defect in row of thick epoxy material and PCB.

• Bulletin of the Korean Chemical Society
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• v.11 no.1
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• pp.71-72
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• 1990

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.6
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• pp.701-706
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• 2005

Pipes, tubes. and tubular sections with external transverse high fins have been used extensively for heating cooling, and degumidifying air and other gases. This work was performed to investigate an air side heat transfer charactieristics of minichannel with tension wound transverse fin. This estimate was confirmed conversion heat capacity the air side surface area enlargement and heat transfer charactieristics performed available inlet tube side hot water mass flux or outlet tube side air frontal air velocity. The most suitable tension wound transverse finned minichannel was measured extremely low in air side pressure drop and fin effectiveness $3.3\~4.4$. The pressure drop $0.9\~2.8Pa$ was ranged frontal air velocity $0.5\~1.2m/s$. It is also appeared that heat transfer in air side could be better conversion heat area which has been increased $330\%$ of heat capacity compared with the bare tube.

• The Pure and Applied Mathematics
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• v.13 no.1 s.31
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• pp.1-10
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• 2006

The unsteady Hartmann flow of an electrically conducting, viscous, incompressible fluid bounded by two parallel non-conducting porous plates is studied with heat transfer. An external uniform magnetic field and a uniform suction and injection are applied perpendicular to the plates while the fluid motion is subjected to a constant pressure gradient. The two plates are kept at different but constant temperatures while the Joule and viscous dissipations are included in the energy equation. The effect of the magnetic field and the uniform suction and injection on both the velocity and temperature distributions is examined.

• Journal of Welding and Joining
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• v.19 no.3
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• pp.292-297
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• 2001

One of the major characteristics that affects the life of welded steel water pipes is the stress distribution caused by welding and external forces. Some studios have bean carried out on the residual stress of steel water pipes. But the results on the stress distributions by welding and complex external forces are rare, because real water pipes operate under the ground and many kinds of external forces act simultaneously on the joints. To understand the complex stress distributions of welded joints, therefore predictions by numerical or analytic methods are required. In this study, temperature and stress distributions in steel water pipes produced by welding are predicted by a three-dimensional finite element method(FEM). Based on these results, stress distributions by welding and complex external forces are evaluated by adopting the same numerical method. The influence of some post weld heat treatments on residual stress distributions is also investigated.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.16 no.3
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• pp.1-37
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• 2003

The epistaxis is commonplace and temporary disease in the field of ENT. In most cases, it is a slight illness, but sometimes, it leads to death because of copious bleeding. The first treatment of epistaxis is stoping hemorrhage, but the real state of treatment in oriental medical is not thoroughgoing enough. So we referred to oriental medical journals and sundry records about etiology and remedy of epistaxis, we got this results. 1. The etiology of epistaxis was mostly bleeding due to heat in the blood by dysfunction of Jang and Bu Gi, there were affection wind-cold by exopathogen, spleen heat to liver, excessive fire of lung meridian, stagnated fire-heat of upper Cho, excessive drinking, bruise and so on. 2. The treatment was used much to remove heat from the blood and activating blood, in case of getting no better, it's used to enriching the blood or clear Gi. 3. The internal remedy of epistaxis was the most used 20times SeogakJihwangtang(犀角地黃湯) to remove heat from the blood and activating blood, and used Jihwangtang(地黃湯), Samhwangbohyultang(三黃補血湯), Jiyuksan(止육散), hueksinsan(黑神散), etc. The drugstuffs were the most used 51times Radix Rehmanniae Preparata((生地黃) to clear heat and remove heat from the blood, produce the body fluids, yin, and used Radix Paeoniae Alba(芍樂) and Radix Glycyrrhizae(甘草), Radix Angelicae Gignatis(當歸), Radix Scutellariae(黃岑), Rhizoma Coptidis(黃連) and Fructus Gardeniae(梔子), etc. 4. The external medical treatment of epistaxis was the most used 16times spraying the granular medication into the cavity and attaching Allii Bulbus(大蒜) to center of the sole or binding the middle finger, etc.

• Journal of Korean Medical classics
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• v.31 no.4
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• pp.79-90
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• 2018

Objectives : In present, various definitions of Zhongshu are being used interchangeably in Korea. The paper attempted to discover the disease of Zhongshu as studied by Lidongyuan, who was ahead of his time. Methods : A database of medical books has been studied to find Lidongyuan's writings on the disease of Zhongshu, and mentions about Li's works in past medical books. The paper contemplated the subject by defining the disease of Zhongshu and reviewing the disputes related to the subject. Results & Conclusions : Lidongyuan gave a detailed explanation on the fact that Zhangjiegu distinguished between Zhongshu and Zhongre, and this was influenced by Shangshu as mentioned in Taipinghuiminhejijufang. Therefore, it can be deduced that he was aware of the fact that summerheat-heat as latent summer heat syndrome is lurking inside the body, not being able to be released. According to the disease of Zhongshu by Lidongyuan, yin cold was receieved secondary after first receiving summerheat-heat. It is either summerheat damaged defensive qi, failure in storing the essence made defensive qi weak, or seasonal reasons have caused the defensive qi to be drained and leave the body exposed to damage by summerheat. This is because the fundamental main cause is the hitting of summerheat, since yin cold was received after the presence of summerheat-heat is made first. Many doctors in the following generation criticized that Lidongyuan's disease of Zhongshu cannot be named as a Zhongshu due to its similarity with Shanghan. However, they cannot be viewed as similar since it is a phenomenon where yin cold becomes congested while the body is weak and heat is generated in the body due to summerheat-heat. The doctors who said they were similar only focused on the external cause that was only the superficial issue. According to Lidongyuan's method, the right way to treat a Zhongshu disease is to use the method of tonifying the qi and eliminating the heat in conjunction with eliminating the internal dampness or treat the external syndrome, or to use a formula to tonify the qi and eliminate the fire heat before eliminating the internal dampness or treating the external syndrome.