• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.463-473
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• 2021

Recently, United States Geological Survey (USGS) distributed Landsat 8 Collection 2 Level 2 Science Product (L2SP). This paper aims to derive land surface temperature from L2SP and to validate it. Validation is made by comparing the land surface temperature with the one calculated from Landsat 8 Collection 1 Level 1 Terrain Precision (L1TP) and the one from Automated Synoptic Observing System (ASOS). L2SP is calculated from Landsat 8 Collection 2 Level 1 data and it provides land surface temperature to users without processing surface reflectance data. Landsat 8 data from 2018 to 2020 is collected and ground sensor data from eight sites of ASOS are used to evaluate L2SP land surface temperature data. To compare ground sensor data with remotely sensed data, 3×3 grid area data near ASOS station is used. As a result of analysis with ASOS data, L2SP and L1TP land surface temperature shows Pearson correlation coefficient of 0.971 and 0.964, respectively. RMSE (Root Mean Square Error) of two results with ASOS data is 4.029℃, 5.247℃ respectively. This result suggests that L2SP data is more adequate to acquire land surface temperature than L1TP. If seasonal difference and geometric features such as slope are considered, the result would improve.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.5
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• pp.675-681
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• 2014

This study was conducted to determine the optimal roasting temperature (90, 100, 110, and 120; fixed time of 20 minutes) of small black coffee beans under various roasting conditions. The roasting temperature range and fixed time were the same as our preceding study. After roasting, the general composition, isoflavone contents, and antioxidant activities were measured. As the results of the proximate composition analysis of small black beans according to roasting conditions, only moisture decreased among them, whereas other general compositions were not affected. The DPPH and ABTS radical scavenging activities were the highest at a roasting temperature of $120^{\circ}C$. Total polyphenol and total flavonoid contents were also highest at $120^{\circ}C$. Isoflavone contents showed a positive correlation with DPPH and ABTS radical scavenging activities, as well as total phenol and flavonoid contents. These results suggest that the optimal roasting conditions of small black beans were determined to be $120^{\circ}C$ for 20 minutes.

• Computational Structural Engineering
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• v.9 no.4
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• pp.15-26
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• 1996

항공기용 복합재료는 여전히 많은 응용의 여지를 갖고 있으나 또한 시급히 해결하여야 할 많은 기술적인 문제점을 갖고 있다. 즉 복합재료 항공기용 구조물은 반드시 인증 절차를 밟아야 실제 항공기에 장착/판매될 수 있는데 수치해석 기법에 의한 구조해석을 거친 기본/상세 설계과정과 성형 제작된 실물 구조물에 대해 가혹환경 조건하(95% 상대습도, 70.deg. C 온도에서 30일간의 방치)에서 설계에서 제시한 최대 하중의 150%를 견디어야 하는 까다로운 full-scale testing 및 각종 복합재료관련 coupon test(표 7 참조)들을 수행하여야 한다. 이와 같은 기술적인 문제점들은 향후 연구결과에 따라 충분히 극복할 수 있으나 이와 더불어 현재 각각의 항공기 제작사가 보유하고 있는 material specification, design manual, process standard 등의 규격이 전세계적으로 통일될 수 있는 제도적인 보완이 뒷받침 된다면 복합재료의 응용도 훨씬 앞당겨질 수 있을 것으로 예상된다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.423-428
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• 1996

피동형원자로 AP600을 참조발전소로하여 설정된 1000MWe급 대용량 피동형원자로의 계통개념에 대한 안전계통 성능 평가 및 코드의 적용성 평가를 목적으로 RELAP5/MOD3코드를 사용하여 대형냉각재상실사고를 모의 해석하였다. 피동형 안전계통으로 축압기, CMT IRWST를 모델하였으며 가압기에 연결된 1단계부터 3단계까지의 자동감압밸브계통을 모델링 하고 4단계 자동감압밸브계통은 각 루프의 고온관에 연결되어 있는 것으로 모델링 하였다. 피동형 안전계통의 모델이 향상된 RELAP5/MOD3.2와 그 이전의 코드인 RELAP5/MOD3.1의 냉각재상실사고 모의계산결과 원자로내의 압력변화, 노심냉각수 주입유량 및 핵연료 피복재 온도 거동이 거의 유사하게 나타났으며 1000MWe급 대용량 피동형원자로의 안전계통은 냉각재 상실사고시 충분한 노심냉각능력을 가지는 것으로 분석되었다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.86-87
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• 2002

우리나라에서 젓갈류의 원료로서 가장 많이 이용될 뿐 아니라 제품 생산량도 가장 많은 멸치를 이용하여, 일시 대량 어획되었을 때 많은 량을 신속하게 처리 할 수 있는 기업적인 발효생산에 목표를 두고, 저식염 속성발효액화물의 가공을 위한 일련의 연구를 계획하였다. 전보에서는 멸치 발효액화물의 가공조건을 설정하기 위하여 기존 저식염 정어리 발효액화물의 가공연구를 참조하여 멸치 내장 효소의 최적온도, 가열 전처리조의 제작, 적정 식염첨가량, 전처리조건 등을 검토하고 상온에서 저식염 멸치 발효액화물을 가공하여 180일간 숙성시키면서 엑스분 질소 및 젓갈류의 맛 성분으로서 중요한 함질소 엑스성분인 유리아미노산과 oligopetide 아미노산을 분석하여 맛과 관련성에 대하여 검토하였다. (중략)

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.517-524
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• 1995

가압경수형 피동형 원자로의 대표적인 노형인 미국 westinghouse사의 AP600을 참조발전소로하여 피동형기기 용량 및 캔드형 원자로냉각재 펌프의 관성에 대한 민감도 분석을 수행하였다. 분석결과 축압기 및 노김보충수탱크는 용량을 20% 감소시킨 경우에 대해서도 핵연료 피복재 온도는 설계기준치를 충분한 여유도를 가지고 만족하고 있는 것으로 분석되었으며, 중력과 밀도차이에 의하여 형성되는 자연대류를 이용하는 피동잔열제거계통의 성능은 초기조건보다는 기기의 용량과 위치에 더 큰 영향을 받는 것으로 나타났다. 또한 원자로냉각재 펌프의 관성이 증가함에 따라 DNB 여유도가 증가하며 저관성일 경우 trip system의 지연시간이 중요한 것으로 나타났다.

• Korean Journal of Materials Research
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• v.10 no.11
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• pp.784-788
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• 2000

The Vickers microhardness was measured on the basal (0001) plane of sapphire single crystals in the temperature range from 25$^{\circ}C$to 1000$^{\circ}C$. The substructure surrounding the indents was investigated using selective chemical polishing and etching, optical microscopy, and trasmission electron microscopy (TEM). At room temperature, cracks were predominant, and at intermediate temperatures (400$^{\circ}C$and 600$^{\circ}C$), extensive rhombohedral twinning was observed. On the other hand, at higher temperatures, prism plane slip bands on prism plane {1120}(원문참조) were dominant in the microstructure. TEM observations revealed that the dislocation substructure at the vicinity of the indents consisted of fairly straight dislocations lying in basal and/or prism planes and aligned along the <1100> and <1120> directions. The details of the glide dissociation of perfect <110> screw dislocations into three collinear 1/3<1100> partials on the prism plane and the Peierls potential for sapphire single crystals were discussed.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.1
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• pp.62-69
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• 2016

Current guidance considers that uniaxially loaded specimen with a deep crack is used for the determination of the ductile-to-brittle transition temperature. However, reactor pressure vessel is under biaxial loading in real and the existence of deep crack is not probable through periodic in-service-inspection. The elastic stress intensity factor and the elastic-plastic J-integral which were used for crack-tip stress field and fracture mechanics assessment parameters. The difference of the loading condition and crack geometry can significantly influence on these parameters. Thus, a constraint effect caused by differences between standard specimens and a real structure can over/underestimate the fracture toughness, and it affects the results of the structural integrity assessment, consequentially. The present paper investigates the constraint effects by evaluating the master curve $T_0$ reference temperature of PCVN (Pre-cracked Charpy V-Notch) and small scale cruciform specimens which was designed to simulate biaxial loading condition with shallow crack through the fracture toughness tests and 3-dimensional elastic-plastic finite element analyses. Based on the finite element analysis results, the fracture toughness values of a small scale cruciform specimen were estimated, and the geometry-dependent factors of the cruciform specimen considered in the present study were determined. Finally, the transferability of the test results of these specimens was discussed.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.60-66
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• 2017

The standard master curve (MC) approach has the major limitation because it is only applicable to homogeneous datasets. In nature, materials are macroscopically inhomogeneous and involve scatter of fracture toughness data due to various deterministic material inhomogeneity and random inhomogeneity. RPV(reactor pressure vessel) steel has different fracture toughness with varying distance from the inner surface of the wall due to cooling rate in manufacturing process; deterministic inhomogeneity. On the other hand, reference temperature, $T_0$, used in the evaluation of fracture toughness is acting as a random parameter in the evaluation of welding region; random inhomogeneity. In the present paper, four regions, the surface, 1/8T, 1/4T and 1/2T, were considered for fracture toughness specimens of KSNP (Korean Standard Nuclear Plant) SA508 Gr. 3 steel to investigate deterministic material inhomogeneity and random inhomogeneity. Fracture toughness tests were carried out for four regions and three test temperatures in the transition region. Fracture toughness evaluation was performed using the bimodal master curve (BMC) approach which is applicable to the inhomogeneous material. The results of the bimodal master curve analyses were compared with that of conventional master curve analyses. As a result, the bimodal master approach considering inhomogeneous materials provides better description of scatter in fracture toughness data than conventional master curve analysis. However, the difference in the $T_0$ determined by two master curve approaches was insignificant.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.677-685
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• 2006

Control of the temperature difference across a section is an effective strategy to minimize the hydration-heat-induced cracks for the structures where internal restraint is dominant. The domestic code, however, overestimates probability of the crack occurrence judging from the foreign codes and construction experiences of real structures. Therefore, the background of the equation presented in the domestic code was investigated step by step to examine validity of the equation, and, as a result, it was found that the equation is established on a basis of simple elastic model where the change of elastic modulus in an early age is not considered. An advanced assessment strategy was proposed taking into account the hypoelastic model which corresponds to an incremental constitutive equation. The presented procedure resulted in an increased crack index, i.e. decreased crack risk, the value of which depends on various conditions of the mix and structures. Also, a prediction equation of the temperature difference was proposed which can readily consider the effect of the curing condition and ambient temperature in a hand calculation. For further study, the assessment equation may be more classified to strictly consider the characteristics of the mix and structures if the analytical and experimental data are accumulated.