• 한국식품위생안전성학회지
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• 제38권5호
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• pp.347-355
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• 2023

본 연구에서는 시가독소 생성 대장균(STEC)을 검출하기 위해 식품공전의 polymerase chain reaction (PCR)검사법과 loop-mediated isothermal amplification (LAMP)를 비교하였다. PCR 및 LAMP의 검출 한계(LOD) 및 정량화 한계(LOQ), 민감도, 특이성 및 효율성을 평가하기 위해 다양한 식품에 STEC를 접종하였다. LOD는 PCR의 경우 10⁴ CFU/mL 이하, LAMP의 경우 10³ CFU/mL 이하로 측정되었다. LOQ 값은 PCR과 LAMP 간에 차이가 없었다. 그러나 4가지 식품군에서 민감도는 양념육이 최대 11.1%, 간소고기가 최소 8.1% 차이가 났다. LAMP는 네 가지 음식 유형 모두에 대해 높은 민감도와 100% 특이도를 보였다. 따라서 LAMP는 식품 유형에 따라 검출률이 비슷하고 특이도와 민감도가 식품공전 PCR보다 우수하기 때문에 STEC에 대한 신뢰할 수 있는 분자 검출 방법이다.

• 소성∙가공
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• 제12권8호
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• pp.710-717
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• 2003

The implicit, finite element analysis program for analyzing the springback in the warm forming process of aluminum alloy sheets was developed. For the description of planar anisotropy in warm forming temperatures, Barlat's yield function is employed, and the power law type constitutive equation is used in terms of working temperatures for the depiction of work hardening in high temperatures. Also, Jetture's 4-node shell elements are introduced for reflecting the mechanical behavior of aluminum alloy sheet and the non-steady heat balance equations are solved for considering heat gain and loss during the forming process. For the springback evaluation, Newton-Raphson iteration method is introduced for overcoming the geometric nonlinearlity problem. In order to verify the validity of the FEM program developed, the stretching bending and springback processes are simulated. Though springback analysis results are slightly bigger than experimental ones, they have the same trend of the decreasing springback as the forming temperature increases.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 제4회 박판성형 심포지엄
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• pp.13-20
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• 2003

The implicit, finite element analysis program for analyzing the springback in the warm forming process of aluminum alloy sheets was developed. For the description of planar anisotropy in warm forming temperatures, Barlat's yield function is employed, and the power law type constitutive equation is used in terms of working temperatures fur the depiction of work hardening in high temperatures. Also, Jetture's 4-node shell elements are introduced for reflecting the mechanical behavior of aluminum alloy sheet and the non-steady heat balance equations are solved for considering heat gain and loss during the forming process. For the springback evaluation, Newton-Raphson iteration method is introduced for overcoming the geometric nonlinearlity problem. In order to verify the validity of the FEM program developed, the stretching bending and springback processes are simulated. Though springback analysis results are slightly bigger than experimental ones, they have the same trend of the decreasing springback as the forming temperature increases.

• Elastomers and Composites
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• 제48권2호
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• pp.161-166
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• 2013

비등온 TGA 실험방법을 이용하여 가교 사이트가 서로 다른 chlorine cure-site ACM 고무와 carboxylic cure-site ACM 고무 두 종류에 대하여 열분해 거동을 연구하였다. 분해 반응이 최대인 점의 온도는 모든 승온 속도에서 carboxylic cure-site ACM 고무의 열분해 특성이 상대적으로 더 안정함을 보여 주었다. Kissinger의 해석 방법에 의한 활성화에너지는 chlorine cure-site ACM 및 carboxylic cure-site ACM 고무에 대하여 각각 118.6 및 105.5 kJ/mol로 나타났으며, Flynn-Wall-Ozawa의 해석방법에서의 전환율 0.1~0.2 범위의 평균과 유사한 값을 나타내었다. 반응차수 해석으로부터 두 시험편 모두 일반적인 고무와 유사한 다중 복합반응에 의하여 열분해 반응이 진행됨을 알 수 있었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.421-424
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• 2011

본 연구에서는 열분석법을 이용하여 혼합 액체연료의 수치해석에 필요한 여러 가지 인자를 측정하였다. 이러한 열분석법에는 열중량 분석방법(TGA, Thermo-Gravimetric Analyzer)과 시차 주사열량 측정법(DSC, Differential Scanning Calorimetry)이 있다. 열중량 분석방법을 통한 비등온 실험(non-isothermal experimental) 결과를 토대로 Freeman Carroll의 수학적인 후처리 방법을 이용하여 미지의 액체연료의 구성 성분에 대한 동역학적 변수인 활성화 온도와 반응차수로 각각 6128.2 K와 1.4를 얻었다. 그 외 다양한 수학적 처리 방법에 따른 동역학적 변수의 값을 구해보았고, 계산 결과는 처리방법에 따라 약간의 차이를 보였다.

• 항공우주시스템공학회지
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• 제17권2호
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• pp.9-15
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• 2023

인공위성의 축소 열모델 생성 작업은 궤도 열해석의 시간 단축과 발사체 연동 열해석 수행을 위해 인공위성 제작 프로젝트에서 반드시 한 번 이상 수행하게 된다. 축소 열모델 생성 방법은 여러가지가 거론되고 있지만, 실무적으로는 직관적이면서도 편리한 등온격자생성법이 가장 많이 사용되고 있다. 그러나 아직까지 등온격자생성법의 자동화에 관한 연구는 부족한 실정이다. 본 논문에서는 온도 허용오차와 고정 노드를 고려한 등온격자생성법 기반 위성 축소 열모델 자동 생성 방법을 제안하였다. 서로 다른 세 가지의 온도 허용오차 케이스를 이용하여 방법론을 검증하였으며, 평균 온도 차이는 ECSS의 축소 열모델 생성 가이드라인(< 2 K)을 만족함을 확인할 수 있었다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 추계 기술심포지움
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• pp.134-137
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• 2001

The cure kinetics of a cycloalipatic epoxy / anhydride / Co(II) system for a no-flow underfill encapsulant, has been studied by using a differential scanning calorimetry(DSC) under isothermal and dynamic conditions over the temperature range of $160^{\circ}C ~220^{\circ}C$. The kinetic analysis was carried out by fitting dynamic/isothermal heating experimental data to the kinetic expressions to determine the reaction parameters, such as order of reaction and reaction constants. Diffusion-controlled reaction has been observed as the cure conversion increases and successfully analyzed by incorporating the diffusion control term into the rate equation. The prediction of reaction rates by the model equation corresponded well to experimental data at all temperature.

• Journal of Biosystems Engineering
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• 제23권1호
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• pp.13-20
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• 1998

Carbonized rice husk(char from rice husk) can be used to improve soils for planting, seedlings, horiculture, pomiculture and truck gardening. Although it is not a fertilizer in nature, it stimulates the growth of plants. Carbonized rice husk is highly recommended for raising soil/water temperature, keeping moisture and aerating roots of plants. The objective of this study was to develop the effective production method of carbonized rice husks by a non-slagging vertical cyclone combustor. A cyclone combustor w vortex collecor Pocket in addition to central collector pocket was selected and tested. Isothermal tests and mixed firing with LPG and rice husk were performed in order to characterize the system. hut rice husk was used during the isothermal test to find the mass collected of rice husk. It was impossible to ignite rice husk itself over the experimental conditions considered in this experiment. The composition of original and carbonized rice husks was analyzed by the ultimate analysis. With the air flow rate of 20 ㎥/h, LPG flow rate of 0.45 1/min, the required carbonized rice husk could be obtained.

• 대한기계학회논문집B
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• 제24권10호
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• pp.1380-1387
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• 2000

The existing theoretical models for steady two-dimensional free convective laminar film condensation of pure saturated or superheated vapor under atmospheric pressure on isothermal vertical wall have been reviewed. To investigate the effects such as inertia, thermal convective and liquid-vapor interface shear stress, the models of constant or variable properties in liquid film for condensation of saturated vapor are compared in detail with Nusselt model. Also, for condensation of superheated vapor, the effects of superheated temperature and variable properties in liquid and vapor layers are examined and then a new correlation is proposed to predict the heat transfer. The results are in good agreement with the Shang's correlation within 2% errors.

• 설비공학논문집
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• 제3권5호
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• pp.365-375
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• 1991

Confined natural convection due to lateral temperature difference in rectangular enclosures was studied numerically and experimentally for the insulated and the constant temperature enclosures. In the case of insulated enclosure, the flow pattern and heat transfer modes are rather simple depending mainly upon Rayleigh number. In the case of isothermal enclosure, however, the phenomena of flow and heat transfer are somewhat complex and interesting due to the stable thermal gradients and various circumstances resulted from four wall temperature conditions. As a dimensionless variable, to describe properly the flow and heat transfer phenomena in the isothermal enclosure, temperature difference ratio ${\Delta}T_v/{\Delta}T_H$ is newly introduced and this parameter seems to be appropriate in the analysis of results on the effect of stabilizing thermal gradient.