• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.3.1-3.1
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• 2009

Normal sintering process of producing porous ceramics is not to sinter perfectly, i.e., stop sintering in middle-process. Our porous ceramic materials are a product of complete sintering. For example if one want to make a porous carborundum, raw carborundum powder is sintered at either lower temperatures than normal sintering temperature or shorter sintering periods than normal sintering time to obtain incompletely sintered materials, i.e., porous carborundum. This implies normally sintered porous ceramic materials can mot be used in high vacuum conditions due to dust coming out from uncompleted sintering. We could produce completely sintered porous ceramic materials. For example, we can produce porous carborundum material by using carborundum particles bonded by glassy material. The properties of this material are similar to carborundum. We could make quasi-zero thermal expansion porous material by using carborundum and particles of negative thermal expansion materials bonded by the glassy material. We apply to sinter them also by microwave to sinter quickly. We also use HIP process to introduce closed pores. We could sinter them in large size to produce $2.5m{\times}2.5m$ ceramic plate to use as a precision plate for flat display industries. This flat ceramic plate is the world largest artificial ceramic plate. Precision plates are basic importance to any advanced electronic industries. The produced precision plate has lower density, lower thermal expansivity, higher or similar damping properties added extra properties such as vacuum vise, air sliding capacity. These plates are highly recommended to use in flat display industries. We could produce also cylindrical porous ceramics materials, which can applied to precision roller for polymer film precision motion for also electronic industries.

• 한국표면공학회지
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• 제43권6호
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• pp.309-314
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• 2010

The numerical study for the effect of various factors that affect the temperature distribution of the process glass installed above the large rectangular heater plate was carried out. For the calculation, heat flux, distance between heat source and process glass plate, effect of vacuum condition and convection in a chamber were considered as important factors. The results showed that the temperature gradient on the glass was increased at the natural convection because of the buoyancy force increases due to the heated air. Also, the more heat flux and distance between the heater plate and glass increases, the more increasing the temperature gradient was. In the case of isothermal heating wall, the temperature variation was smaller than the uniform heat flux condition.

• 한국진공학회지
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• 제1권1호
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• pp.198-205
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• 1992

고집적 회로제작에 필수적인 평탄화 기술을 SOG를 이용하여 개발하였다. 1.5 micron double metal 기술의 공정변수들을 통계적 실험계획법을 적용하여 주요변수들을 찾 아내고 그들을 최적화하였다. 최적공적 조건은 SOG 도포 횟수는 2회, hot plate bake는 $300^{\circ}C$에서 충분히, 그리고 furnace curing은 $400^{\circ}C$ 이하에서 40분간 진행하는 것이었다.

• 한국축산식품학회지
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• 제18권2호
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• pp.125-131
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• 1998

This study were carried out for investigation of microbiological characteristics, and establishment of shelf-life of Korean vacuum packaged chilled pork hams for export. The samples were stored at 0$\pm$1$^{\circ}C$ (A and B companies) and 2$\times$1$^{\circ}C$ (C and D companies). In the analysis of microorganisms, the numbers of total plate counts were 3.72$\times$103~1.15$\times$104CFU / $\textrm{cm}^2$ at initial time. After 30 days, total plate counts were over 1$\times$106CFU / $\textrm{cm}^2$ in samples. Anaerobic counts were over 1$\times$106CFU / $\textrm{cm}^2$ in samples excluded one of A company after 30 days. Using regression equations, the estimation of shelf life were made : 32~37 days in storing at $0^{\circ}C$ and 27 days at 2$^{\circ}C$. In this case, the determination coefficients were 0.8624~0.9515 and 0.8236~0.8565, respectively.

• 한국가금학회지
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• 제23권4호
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• pp.203-207
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• 1996

This experiment was carried out to find out the effects of packing methods on shelf-life and hy-giene of breast and thigh meats in chicken. The carcass weights were about 1.6 kg per bird, and chilled by air spray method. The breast and thigh meats were packed by either vacuum or atmosphere packing methods. Samples were analyzed at 1, 4, 8, 12 and 16 wk after quick freezing at -45˚C for 35 min. Regardless of packing method. The thiobarbituric acid(TBA) values of thigh meats after 1 wk of storage were higher than those of breast meats. The TBA values of both treatments were increased as storage period extended. In addition, the TBA values of vacuum packed meats were lower than those of atmosphere packed meats. The VBN(volatile basic nitrogen) values, regardless of packing method, at 1 wk of storage were higher than those of breast meats. The VBN contents of breast and thigh meats after 16 wk of storage increased markedly, but failed to show significant difference between the two packaging methods. Total plate counts of breast and thigh meats were increased gradually as storage period extended, and the total plate count of breast meat was higher than that of thigh meat. The coliform bacteria were not detected until 16 wk after storage.

• 한국태양에너지학회 논문집
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• 제21권4호
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• pp.63-71
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• 2001

This work has been carried out to find the ideal operating conditions for solar vacuum tube collectors which are widely used at present. Various types of solar collectors including a flat plate one were experimentally tested and examined to determine their thermal efficiencies and operating characteristics. Generally, solar vacuum tubes can be classified into two groups according to their design features. Of these, one is characterized by the insertion of a metallic device(such as a finned heat pipe) in an evacuated glass tube for the collection and transportation of solar energy. The other utilizes double glass tubes where the smaller one is contained inside the bigger one and soldered to each other after the small gap between them is evacuated. Both of these solar collectors are designed to minimize convection heat losses by removing the air which is in direct contact with the absorber surface. The performance of the former type can be readily analyzed by applying the relevant correlations developed for flat plate solar collectors. This has been demonstrated in the present study for the case of a solar collector where a heat pipe is inserted in an evacuated tube.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.195-195
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• 2015

반도체 제조 시 ohmic contact을 형성하고, barrier metal layer형성을 위해 NH3 기체를 사용하는 rapid thermal nitridation (RTN)은 반도체 공정에 있어 매우 중요한 핵심 기술이다. 그러나 공정 진행 시 발생하는 공정 부산물에 의한 chamber오염으로 인해 매우 정확히 입사 되어야 할 thermal energy의 controllability가 저하되고 있어, 미세 공정능력 구현의 한계에 부닥치고 있다. 본 연구에서는 quartz plate liner를 적용하여 RTN 공정에서 발생하는 공정 부산물인 ammonium chloride (NH4Cl)의 chamber 표면 증착을 최소화하였고, 공정 진행 온도의 controllability를 확보하였다.

• 한국전기전자재료학회논문지
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• 제20권4호
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• pp.374-380
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• 2007

In this paper a nobel optimum design method is presented for a shield in a vacuum interrupter which is equipped in switchgear to improve its electric insulation capability. The design of Taguchi experiment method which is based on the results by finite element method is used to find optimum design conditions. The important design factors are chosen at first and the concept of signal to noise ratio is applied to evaluate the vacuum interrupter performance, and the optimal values of each parameters are determined. From the results of various analyses, it is shown that the shield plate in circuit circuit breaker compartment of switchgear can reduce the concentration of electric field intensity. This method is very useful to design the construction of a shield in a short time. Consequently, the insulation capability of circuit breaker compartment in a gas insulated switchgear is improved by adopting an additional optimized shaped shield.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.177-180
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• 2002

A numerical model to obtain the temperature distribution in a radiation shield of cryogenic systems was proposed. Conformal mapping was used to transform the eccentric physical region of the upper plate to the concentric numerical region. The effects of the thickness of the radiation shield, the emissivities of the vacuum chamber and the radiation shield, and the eccentricity between the centers of the upper plate and the contact area with a cryocooler on the maximum temperature difference in a radiation shield were shown.

• 한국초전도ㆍ저온공학회논문지
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• 제4권1호
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• pp.124-128
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• 2002

A numerical model to obtain the temperature distribution in a radiation shield of cryogenic systems was proposed. Conformal mapping was used to transform the eccentric physical region of the upper plate to the concentric numerical region. The effects of the thickness of the radiation shield, the emissivities of the vacuum chamber and the radiation shield, and the eccentricity between the centers of the upper plate and the contact area with a cryocooler on the maximum temperature difference in a radiation shield were shown.