• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1459-1462
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• 2007

In general a thermoelectric cooler (TEC) consists of a series of P type and N type thermoelectric materials sandwiched between two wafers. When a DC current passes through these materials, three different effects take place; Peltier effect, Joule heating effect and heat transfer by conduction due to temperature difference between hot and cold plates. In this study we have developed a micro TEC using $Bi_2Te_3$ (N type) and $Bi_{0.5}Sb_{1.5}Te_3$ (P type) thin films. In order to improve that performance of a micro TEC, we made 10 um height TE legs using special PR only for lift-off. We measured COP (coefficient of performance) and temperature difference between hot and cold connectors with current.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1987.06a
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• pp.50-56
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• 1987

A mechanical face seal is most commonly used to seal liquids and gases at various speeds, pressures and temperatures. The primary seal ring is in sliding contact with the seal seat and as a result heat in the vicinity of the interface is generated. Local temperatures at points along the circumferential direction will fluctuate as asperities on the surfaces pass. This kind of fluctuation of temperature has been investigated to take place. This may lead to the hot spots phenomenon between the contacting asperities. Sibley and Allen showed photographic evidence of systemically moving hot spots in the contact zone. The appearance of such a temperature disturbance has been attributed to a kind of thermoelastic instabilities between two surfaces: This involves a feedback loop which comprises localized elevation of frictional heating, resultant localized thermal bulding, localized pressure increase as the result of the bulging and futher elevation of frictional heating as the result of the pressure increase. The heating of hot spots will be continued until the expanded material due to the frictional heating is worn off. Therefore to predict the speed of temperature propagation into the body is essential to the analysis of heat transfer on the edge of the seal.

• Journal of Animal Science and Technology
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• v.64 no.2
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• pp.343-352
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• 2022

Pig slaughterhouses harbor high humidity because of the necessary cleaning that takes place simultaneously with slaughter, which facilitates the existence of mold. Due to the enclosed space, there are several limitations to the control of mold growth with respect to cleaning, ventilation, and drying. In this study, the prevalence of fungi was investigated in four pig slaughterhouses in Korea. Four fungi (Aspergillus niger, Penicillium commune, Penicillium oxalicum, and Cladosporium cladosporioides) were detected with the highest frequency. These four strains were subjected to various treatments to reduce their growth. The fungi were inoculated onto stainless steel (SS) chips and treated with ultraviolet (UV)-C irradiation and hot water. Individual treatments with UV-C (15, 30, 90, 150, 300, and 600 mJ/cm²), and hot water (60, 65, 70, and 83℃) were performed to sanitize the SS chips. Simultaneous cleaning with 60℃ hot water and more than 150 mJ/cm² of UV-C reduced the fungal incidence by > 6.5 Log from 6.6-7.0 Log CFU/cm² (initial count). Our results demonstrate that a combined treatment of UV-C and hot water is the most economical and convenient way to prevent microbiological contamination of small tools (such as knives and sharpeners) and steel surfaces in slaughterhouses.

• Journal of Internet of Things and Convergence
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• v.8 no.5
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• pp.33-39
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• 2022

A storage device used in the mobile computing field should have low power, light weight, durability, etc., and should be able to effectively store and manage large-capacity data generated by users. NAND flash memory is mainly used as a storage device in the field of mobile computing. Due to the structural characteristics of NAND flash memory, it is impossible to overwrite in place when a data update request is made, so it can be solved by accurately separating requests that frequently request data update and requests that do not, and storing and managing them in each block. The classification method for such a data update request is called a hot data identification method, and various studies have been conducted at present. This paper continuously records the occurrence of data update requests using a counting filter for more accurate hot data validation, and also verifies hot data by considering how often the requested update requests occur during a specific time.

• Journal of Korea Foundry Society
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• v.22 no.1
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• pp.11-16
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• 2002

Hot deformation behavior of GCD-50 cast iron has been investigated by employing the compressive test. Phenomenological deformation behaviors, which were modeled based on the dynamic materials model and the kinetic model, have been correlated with the microstructural change taken place during compression. Microstructural investigation revealed that the adiabatic shear band caused by the locallized deformation was taken place in low temperature and high strain rate. On the other hand, the wavy and curved grain boundaries, which repersent the occurrence of dynamic microstructure change such as dynamic recovery and dynamic recrystallization, were observed in high temperature and low strain rate. Deformation model based on hyperbolic sine law has also been suggested.

• Journal of the Korean Home Economics Association
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• v.43 no.1 s.203
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• pp.145-165
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• 2005

In 1937, most Korean compatriot who lived in Yunhaeju moved to Kazakhstan and Uzbekistan in Central Asia following the deportation policy of Russia. Korean compatriot have kept their traditional life style for 140 years, without a deep relationship with Korea. This study examined the heating systems of Korean compatriot in Yunhaeju, Kazakhstan and Uzbekistan, Russia. A literature review and field research, based on Ethnography as a research method, was employed. The results of the research were as following: 1) Korean compatriot in Yunhaeju use a Pechika, which is a radiator that uses hot water, and a Gudul as the main heating systems, but the use of a Pechika was most common. A Pechika functions for cooking as well as for warming the house. The room with the Gudul was connected to the kitchen, so this space was used as a place for cooking and eating, for family members to meet. Many kinds of fuel, like gas and electricity, were used to power the heating systems. 2) Korean compatriot in Kazakhstan use radiators, with hot water as the main heating system, with ratio using Gudul used in this region being the highest of all the three areas. The most common fuels used for a Gudul were wood and coal, and gas was also used in cooking. The room with the Gudul was planned to be located beside the fireplace, without any walls. The people using a Gudul use that place for eating and meeting, as well as for family members to sleep. 3) The main heating system of Korean compatriot in Uzbekistan was a radiator using hot water, and those with pipes containing hot water buried under the floor were very common. The function is very similar to that of a Gudul, so most people using this type of radiator would sleep on the floor. Those people with a traditional Gudul not using them were mostly in Uzbekistan. The reason for this was that the family members had diminished, so it was hard work for elderly parents to manage an extra building containing a Gudul. Gas was the fuel generally used for heating and cooking in Uzbekistan. 4) Guduls were used in the Korean compatriot's houses in all three areas, even though they have changed in structure to adapt to the Russian life style. However, Guduls have still been functioning to maintain a traditional life style in Korean compatriot's houses for the gathering of family members.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.265-268
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• 2004

Molecular clouds present many levels of structure, including clumps and cores of varying size and density. We present a brief summary of these cores, describing their observed physical properties and their place in the star formation process. We conclude with some speculation about pre-proto-stellar stages of molecular cores and the observational challenges in their observation.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.889-896
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• 2001

The reaction of gas-phase atomic bromine with highly covered chemisorbed hydrogen atoms on a silicon surface is studied by use of the classical trajectory approach. It is found that the major reaction is the formation of HBr(g), and it proceeds th rough two modes, that is, direct Eley-Rideal and hot-atom mechanism. The HBr formation reaction takes place on a picosecond time scale with most of the reaction exothermicity depositing in the product vibration and translation. The adsorption of Br(g) on the surface is the second most efficient reaction pathway. The total reaction cross sections are $2.53{\AA}2$ for the HBr formation and $2.32{\AA}2$ for the adsorption of Br(g) at gas temperature 1500 K and surface temperature 300 K.

• Journal of Astronomy and Space Sciences
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• v.29 no.1
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• pp.47-49
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• 2012

Massive binary stars lose mass by two mechanisms: jet-driven mass loss during periods of active mass transfer and by wind-driven mass loss. Beta Lyrae is an eclipsing, semi-detached binary whose state of active mass transfer provides a unique opportunity to study how the evolution of binary systems is affected by jet-driven mass loss. Roche lobe overflow from the primary star feeds the thick accretion disk which almost completely obscures the mass-gaining star. A hot spot predicted to be on the edge of the accretion disk may be the source of beta Lyrae's bipolar outflows. I present results from spectropolarimetric data taken with the University of Wisconsin's Half-Wave Spectropolarimeter and the Flower and Cook Observatory's photoelastic modulating polarimeter instrument which have implications for our current understanding of the system's disk geometry. Using broadband polarimetric analysis, I derive new information about the structure of the disk and the presence and location of a hot spot. These results place constraints on the geometrical distribution of material in beta Lyrae and can help quantify the amount of mass lost from massive interacting binary systems during phases of mass transfer and jet-driven mass loss.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.217-219
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• 2001

플래쉬 메모리는 데이터 저장 및 변경이 가능한 비휘발성 메모리로 가벼운 무게, 낮은 전력 소모, 충격에 대한 저항성과 빠른 데이터 처리 능력 때문에 이동형 컴퓨터 시스템에서 사용하기에 적당하다. 그러나 플래쉬 메모리는 덮어쓰기(update-in-place)가 불가능하고 각 메모리 셀에 대해 초기화 작업(erasing operation)의 수가 제한되어 있다. 이러한 단점들을 고려하여 세그먼트의 데이터 중 유효 데이터의 비율과 hot 데이터(가까운 시간 안에 update가 될 것이라는 예상되는 data)의 수, 세그멘트가 초기화되었던(easing) 횟수 등을 고려한 새로운 초기화 기법(cleaning policy)을 제안하고자 한다.