• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.143.2-143.2
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• 2005

• 한국산학기술학회논문지
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• 제13권11호
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• pp.5247-5253
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• 2012

본 연구는 식혜와 액상 커피의 제조 공정중 HACCP system을 이용하여 한계 기준 설정을 위한 목적으로 실시하였다. 살균공정의 한계 기준 설정은 충북 진천시 소재의 P사에서 약 30일 (2012년 4월 1~30일) 동안 살균온도와 시간을 측정하였다. 그 결과, 멸균전에는 식혜와 액상 커피에서 미생물이 검출되었다. 반면에 식혜(238mL Can, 500mL and 300mL PP, 1.8L PP)에서 모든 미생물은 살균($121{\pm}1^{\circ}C$에서 $15{\pm}1$, $35{\pm}1$ and $45{\pm}1$분) 후에는 검출되지 않았고, 액상 커피도 살균($121{\pm}1^{\circ}C$, $20{\pm}1$분)후 검출되지 않았다. 가장 적당한 온도와 시간을 결정하기 위한 살균기 조건은 $121{\pm}1^{\circ}C$, $20{\pm}1$분이었다. 결론적으로, 살균공정은 유해미생물(일반세균, 대장균군, 병원성 미생물)를 예방, 감소 또는 제거할 수 있는 좋은 대안이 될 것이다. 따라서 품질 유지와 생물학적 안전성을 위한 살균 온도와 시간의 한계기준은$121{\pm}1^{\circ}C$에서 $20{\pm}1$분으로 설정하였다. 그리고 HACCP 계획은 살균 공정중 모니터링 방법과 모니터링 주기, 문제 해결 방법, 교육, 훈련, 기록 관리 등을 위하여 필요하여 이를 제안하고자 한다.

• 한국패류학회지
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• 제24권1호
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• pp.59-66
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• 2008

본 연구는 피조개의 용존산소에 대한 내성을 구명하기 위하여 경남 진해만에 서식하는 피조개를 대상으로 수온과 염분에 대한 용존산소 농도별 생존율, 산소소비율 및 외부 형태 변화 등을 조사하였다. 피조개의 용존산소에 대한 $LC_{50}$은 수온 $15^{\circ}C$-일반해수와 염분 $26{\pm}1$ psu에서 7일 동안 각각 1.98mg/L (신뢰한계: 1.45-2.39 mg/L)와 2.63 mg/L (신뢰한계: 1.76-3.37mg/L)였다. 한편 $25^{\circ}C$-일반해수와 염분 $26{\pm}1$ psu에서는 각각 3.89 mg/L (신뢰한계: 3.36-4.55 mg/L)과 3.74 mg/L (신뢰한계 3.19-4.43 mg/L)으로 고수온에서 용존산소에 대한 내성이 약한 것으로 나타났다. 산소소비율은 모든 실험구에서 저산소 노출기간동안 감소하였으며, 회복가능성을 파악하기 위하여 일반해수로 전환시킨 경우 산소소비율을 증가시키며 산소부채에 의한 회복반응을 보였으나 모두 폐사하였다. 저산소 노출기간동안 패각 각정부위의 색깔이 검게 변화하는 것이 관찰되었다. 이 자료는 피조개 집단 폐사원인 구명을 위한 기초자료로 활용할 수 있을 것으로 여겨진다.

• 터널과지하공간
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• 제6권2호
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• pp.101-121
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• 1996

The thermomechanical characteristics of rocks such as temperature dependency of strength and deformation were experimentally investigated using Iksan granite, Cheonan tonalite and Chung-ju dolomite for proper design and stability analysis of underground structures subjected to temperature changes. For the temperature below critical threshold temperature $T_c$, the variation of uniaxial compressive strength, Young's modulus, Brazilian tensile strength and cohesion with temperature were slightly different for each rock type, but these mechanical properties decreased at the temperatures above $T_c$ by the effect of thermal cracking. Tensile strength was most affected by $T_c$, and uniaxial compressive strength was least affected by $T_c$. To the temperature of 20$0^{\circ}C$ with the confining prressure to 150 kg/$\textrm{cm}^2$, failure limit on principal stress plane and failure envelope on $\sigma$-$\tau$ plane of Iksan granite were continuously lowered with increasing temperature but those of Cheonan tonalite and Chung-ju dolomite showed different characteristics depending on minor principal stress on principal stress plane and normal stress on $\sigma$-$\tau$ plane. The reason for this appeared to be the effect of rock characteristics and confining pressure. Young's modulus was also temperature and pressure dependent, but the variation of Young's modulus was about 10%, which was small compared to the variation of compressive strength. In general, Young's modulus increased with increasing confining pressure and increased or decreased with increasing temperature to 20$0^{\circ}C$ depending on the rock type.

• 반도체디스플레이기술학회지
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• 제12권4호
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• pp.39-44
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• 2013

In the semiconductor heat-treatment process, the temperature uniformity determines the film quality of a wafer. This film quality effects on the overall yield rate. The heat transfer of the wafer surface in the heat-treatment process equipment is occurred by convection and radiation complexly. Because of this, there is the nonlinearity between the wafer temperature and reactor. Therefore, the accurate prediction of temperature on the wafer surface is difficult without the direct measurement. The thermal camera and the T/C wafer are general ways to confirm the temperature uniformity on the heat-treatment process. As above ways have limit to measure the temperature in the precise domain under the micro-scale. In this study, we developed the thin film type temperature sensor using the MEMS technology to establish the system which can measure the temperature under the micro-scale. We combined the experiment and numerical analysis to verify and calibrate the system. Finally, we measured the temperature on the wafer surface on the semiconductor process using the developed system, and confirmed the temperature variation by comparison with the commercial T/C wafer.

• Journal of Mechanical Science and Technology
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• 제15권11호
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• pp.1533-1540
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• 2001

A high-temperature sodium stainless steel heat pipe was fabricated and its performance has been investigated. The working fluid was sodium and it was sealed inside a straight tube container made of stainless steel. The amount of sodium occupied approximately 20% of the total volume of the heat pipe and its weight was 65.7gram. The length of a stainless steel container is 1002mm and its outside diameter is 25.4mm. Performance tests were carried out in a room air condition under a free convective environment and the measured temperatures are presented. The start-up behavior of the heat pipe from a frozen state was investigated for various heat input values between 600W and 1205W. In steady state, axial temperature distributions of a heat pipe were measured and its heat transfer rates were estimated in the range of vapor temperature from 50$0^{\circ}C$ to 63$0^{\circ}C$. It is found that there are small temperature differences in the vapor core along the axial direction of a sodium heat pipe for the high operating temperatures. But for the range of low operating temperatures there are large temperature drops along the vapor core region of a sodium heat pipe, because a small vapor pressure drop makes a large temperature drop. The transition temperature was reached more rapidly in the cases of high heat input rate for the sodium heat pipe.

• 한국화재소방학회논문지
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• 제24권2호
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• pp.76-81
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• 2010

톨루엔의 안전한 취급을 위해서 $25^{\circ}C$에서 폭발한계와 폭발한계 온도의존성을 고찰하였다. 또한 인화점과 최소발화온도를 측정하였다. 공정의 안전을 위해서 톨루엔의 폭발하한계는 1.13vol%, 상한계는 7.9vol%를 추천한다. 유통법에 의한 하부인화점은 $5^{\circ}C$, 상부인화점은 $40^{\circ}C$로 측정되었으며, Setaflash 장치에 의한 상부인화점은 $41.5^{\circ}C$로 측정되었다. ASTM E659-78 장치에 최소자연발화온도는 $547^{\circ}C$로 측정되었다. 그리고 톨루엔의 새로운 폭발한계 온도의존식을 제시하였으며, 제시한 온도의존식은 문헌값과 일치하였다.

• 대한영양사협회학술지
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• 제12권2호
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• pp.157-171
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• 2006

This study was intended to suggest HACCP-based standard recipe for bellflower roots, classified as no thermal cooking process, served in a university foodservice operation. The time-temperature and microbial contamination level in each cooking step were analyzed. The temperatures of bellflower root, peeled garlic and green onion at receiving were at 13.8$\pm$2.8, 12.6$\pm$2.9 and 13.7$\pm$$0.8^\circC$ respectively, which were above the temperature limit. The time consumed for pre-preparation was up to 90 min at room temperature having high microbial growth potential. The levels of total plate counts (TPC) of bellflower root and garlic were over the limit of $10^6$ CFU/g as were the numbers of coliforms in bellflower roots. There were no microbial reductions in pre-preparation and cooking, which resulted in over $10^5$- $10^6$ CFU/g of TPC at service step. Two CCPs identified were washing/sanitation at pre-preparation and service steps. The control measures were washing/sanitation and temperature control. It was verified that CCPs for no cooking process developed in preceding studies were applicable for the microbiological food safety of this menu item. The HACCP-based standard recipe was developed to produce a quantity for 100 servings by observing the critical limits established for CCPs. These results suggest that the selection of proper provider is imperative to control the microbial contamination of raw materials at purchasing step. Also, the sanitary education program should be developed for the employees to understand and comply the HACCP plan and standard recipe.

• 한국연소학회지
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• 제19권3호
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• pp.1-7
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• 2014

Experimental study has been carried out to understand combustion characteristics of a swirl-stabilized premixed gas turbine combustor for power generation. $NO_x$ and CO emissions, extinction limit, pressure loss, and temperature distribution were measured for various operating conditions. Results show that, with increasing inlet air temperature, $NO_x$ is increased due to a higher adiabatic flame temperature while CO is increased or decreased for low or high A/F ratio regime, respectively. depending on the flame location. With decreasing load from the design condition, $NO_x$ is decreased as thermal load is reduced. With further decreasing load, however, $NO_x$ is increased due to a longer residence time. CO is decreased and then increased with decreasing load. Flame extinction limit is extended with increasing inlet air temperature as the recirculation strength is enhanced.

• Nuclear Engineering and Technology
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• 제35권4호
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• pp.356-368
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• 2003

Material properties such as coolant specific heat, film heat transfer coefficient, cladding thermal conductivity, surface diffusion coefficient of the multi-bubble are improved in MACSIS-Mod1. The axial power and flux profile module was also incorporated with irradiation history. The performance and feasibility of the updated driver fuel pin have been analyzed for nominal parameters based on the conceptual design for the KALIMER breakeven core by MACSIS-MOD1 code. The fuel slug centerline temperature takes the maximum at 700mm from the bottom of the slug in spite of the nearly symmetric axial power distribution. The cladding mid-wall and coolant temperatures take the maximum at the top of the pin. Temperature of the fuel slug surface over the entire irradiation life is much lower than the fuel-clad eutectic reaction temperature. The fission gas release of the driver fuel pin at the end of life is predicted to be $68.61\%$ and plenum pressure is too low to cause cladding yielding. The probability that the fuel pin would fail is estimated to be much less than that allowed in the design criteria. The maximum radial deformation of the fuel pin is $1.93\%$, satisfying the preliminary design criterion ($3\%$) for fuel pin deformation. Therefore the conceptual design parameters of the driver fuel pin for the KALIMER breakeven core are expected to satisfy the preliminary criteria on temperature, fluence limit, deformation limit etc.