• 한국도로학회논문집
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• 제14권5호
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• pp.57-65
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• 2012

PURPOSES: It is important to consider the long-term performance of concrete pavement, because concrete pavement is more exposed to the various environmental conditions than any other concrete structures. One of the several methods to evaluate the long-term performance of concrete during winter is KS F 2456. Relative dynamic modulus of elasticity shows the resistance to freezing and thawing. METHODS: To measure relative dynamic modulus of elasticity, ultra sonic is generally used. But in this study, to measure the relative dynamic modulus of elasticity, both ultra sonic and shear wave were used and then compared each other. RESULTS: The results from the measurement by ultrasonic wave and shear wave were divided into three types. Type 1 : Specimens are good and relative dynamic modulus of elasticity did not decrease until 300 cycle. Type 2 : The relative dynamic modulus of elasticity decreased from the late cycle.(about 150 cycle later) Type 3 : The relative dynamic modulus of elasticity consistently decreased from the beginning. As a result of ANOVA, there is no difference according to measuring method, in type 2 and 3. But there is a difference according to measuring method, in type 1's relative dynamic modulus of elasticity. CONCLUSIONS: It is proved that shear wave can be used to understand the damage tendency of relative freezing and thawing and to measure the relative dynamic modulus of elasticity.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.268-270
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• 2007

NIR을 이용하여 시간 변화에 따른, 소 등심육의 부위별(살코기와 지방)특성을 조사 하였다. 소 등심육의 특성은 분광분석법을 사용하여 측정하였다. 육질은 총 세 가지 종류의 Sample로 구분 하여 각각의 Sample 마다 3Point 씩 Point를 정하여 측정 하였고, 냉동상태와, 20분경과 후 그리고 해동 40분경과 후를 측정 하였다. 측정결과 Moglobin의 분포에 따라 광도의 변화가 발생하였고, 이를 통해 소 등심육의 살코기와 지방 분포에 따라 고기 육질의 품질 판별 및 특성의 파악이 가능할 것으로 예상된다.

• 방재저널
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• 제13권4호
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• pp.158-159
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• 2011

• 방재저널
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• 제15권2호
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• pp.90-91
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• 2013

• Asian-Australasian Journal of Animal Sciences
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• 제13권3호
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• pp.313-316
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• 2000

Three Holstein steers, fitted with ruminal and duodenal cannulas, were used in a replicated $3{\times}3$ Latin square design to determine the digestibility of dietary nitrogen in total digestive tract by three methods, 1) mobile nylon bag (MNB); 2) total fecal collection (TFC); and 3) washed fecal sample after freezing and thawing through a sieve with a pore size of $45{\mu}m$ (WFS). A basal diet of oaten hay-barley was supplemented with one of the following protein sources; soybean meal, fish meal or blood meal. Steers were fed at a level of 2% of body weight. The experimental diets were contained approximately 1.85% nitrogen. There were no differences (p>0.05) among the diets on DM, NDF and nitrogen disappearances, and the diet results were pooled to assess the methods. Total tract disappearances of dry matter and neutral detergent fiber were 61.6, 71.1 and 78.9 and 25.3, 63.2 and 64.6 for MNB, TFC and WFS methods, respectively. The lower digestibility of DM and NDF in the MNB method could be a result of low ruminal incubation time. The TFC method had the lower (p<0.05) determination of nitrogen disappearance in the total digestive tract than the MNB and WFS methods. On the other hand, nitrogen disappearance in the total digestive tract determined by the WFS technique was comparable to that in MNB technique, as there was no significant difference (p>0.05) between the methods. It is shown that the disappearance of dietary nitrogen in the total digestive tract could be estimated in the intact animals by using washed fecal sample prior to freezing and thawing.

• Clinical and Experimental Reproductive Medicine
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• 제39권4호
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• pp.153-160
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• 2012

Objective: The aim of this study was to compare vitrification optimization of mouse embryos using electron microscopy (EM) grid, cryotop, and thin plastic strip (TPS) containers by evaluating developmental competence and apoptosis rates. Methods: Mouse embryos were obtained from superovulated mice. Mouse cleavage-stage, expanded, hatching-stage, and hatched-stage embryos were cryopreserved in EM grid, cryotop, and TPS containers by vitrification in 15% ethylene glycol, 15% dimethylsulfoxide, 10 ${\mu}g/mL$ Ficoll, and 0.65 M sucrose, and 20% serum substitute supplement (SSS) with basal medium, respectively. For the three groups in which the embryos were thawed in the EM grid, cryotop, and TPS containers, the thawing solution consisted of 0.25 M sucrose, 0.125 M sucrose, and 20% SSS with basal medium, respectively. Rates of survival, re-expansion, reaching the hatched stage, and apoptosis after thawing were compared among the three groups. Results: Developmental competence after thawing of vitrified expanded and hatching-stage blastocysts using cryotop and TPS methods were significantly higher than survival using the EM grid (p<0.05). Also, apoptosis positive nuclei rates after thawing of vitrified expanded blastocysts using cryotop and TPS were significantly lower than when using the EM grid (p<0.05). Conclusion: The TPS vitrification method has the advantages of achieving a high developmental ability and effective preservation.

• 대한영양사협회학술지
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• 제13권4호
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• pp.345-356
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• 2007

The purpose of this study was to investigate utilization and storage management practice of the frozen and refrigerated foods in school foodservice. 222 dietitians employed in school foodservice were surveyed. In school foodservice, the refrigerated stock farm products and seafoods (78.3%) were more used rather than frozen products (47.5%). According to school foodservice characteristics, the refrigerated meats including dairy products were more frequently used in elementary and middle schools than high school foodservice. On the other hand, the foodservice in high school used more frozen seafoods and processed foods than elementary school did. The data also showed a tendency for the contracted foodservice using more frozen meats and seafoods rather than refrigerated products when comparing with the self-operated foodservice. In terms of receiving conditions, storage methods and storage time, the result indicated that frozen or refrigerated products were often delivered at inappropriate temperature. Especially some products which were needed to be shipped and stored at refrigerated temperature such as mollusks, were delivered and kept at room temperature. The most frequently used thawing method were running water (56.9%), however, the frozen products were often sitted at room temperature for the purpose of thawing. According to the results, several inappropriate handling processes for frozen and refrigerated products were found in school foodservice. In order to improve handling process for frozen and refrigerated products, recognition of food handlers' weakness about storage and distribution, development of radical standards for receiving conditions, storage and thawing methods should be debated.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.621-624
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• 2008

콘크리트 구조물에 적용되는 보수재료는 적용되는 환경요인에 따라 품질특성이 다르게 나타난다. 국내의 보수재료에 대한 내구성 평가는 다양한 환경요인에 따른 시험법의 미비로 내구성에 대한 품질성능이 확보되지 않은 실정이다. 본 연구에서는 국내에서 생산되는 보수재료에 대하여 적용환경에 따른 동결융해저항성능을 BS EN 13687에 준하여 시험하였고, 국내시험규격(KS F 4716)과 비교 분석하였다. 연구결과 건습반복과 염수침지동결융해 시험 후의 부착강도 값은 보수재료의 종류 및 시편의 크기에 따라 다소 큰 차이가 나타났다. 보다 양호한 보수재료의 품질관리를 위해서는 적용환경에 따른 다양한 동결융해저항시험방법에 대한 규격제정이 요구된다.

• Clinical and Experimental Reproductive Medicine
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• 제30권2호
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• pp.127-133
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• 2003

Objective: The aim of this study was to investigate the morphological aspects of testicular tissue before and after freezing-thawing by light and transmission electron microscopy. Methods: Tissue biopsies were carried out on mouse testis for freezing. Samples in medium containing 20% glycerol were frozen by computer-controlled freezing program. The effect of freezing-thawing on the structural change of testicular tissues were examined by light and electron microscopy. Results: The freezing-thawing procedure had no significant effect on tubular diameter. However, it caused folding of the lamina propria, and notable damage to Sertoli cells, spermatogonia and spermatocytes. The cells were detached, desquamated from the basal lamina and had increased vacuolization. Round spermatids, elongated spermatids and spermatozoa were less affected, and most of them maintained their normal structure. Conclusions: The structure of spermatogonia, spermatocyte and basal compartments in seminiferous epithelium was significantly altered by freezing-thawing procedure of mouse testicular tissues. Thus, we need to develop a more reliable method for the cryopreservation of testicular tissues.

• 한국식품저장유통학회지
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• 제19권2호
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• pp.201-208
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• 2012

본 연구는 엄나무와 참죽 햇순의 blanching 조건을 제시하기 위해 blanching 온도와 식염의 농도에 따른 품질 변화와 관능적 특성을 평가하였다. 또한 해동방법에 따른 이화학적 및 관능적 특성을 평가하여 엄나무와 참죽 햇순의 품질을 향상시킬 수 있는 해동방법을 제시하고자 하였다. 엄나무와 참죽 햇순은 식염 첨가량(무첨가, 1%, 2%)과 blanching 시간(3분, 6분)을 달리하여 blanching하였으며, 해동은 저온($4^{\circ}C$), 상온($25^{\circ}C$), microwave를 이용하였다. Blanching 조건에 따른 색도, chlorophyll 함량, texture 측정 및 관능검사를 실시한 결과, 엄나무와 참죽 햇순은 $95^{\circ}C$, 식염 첨가 없이 3분간 blanching한 경우 품질 변화와 기호도가 가장 높게 나타났다. 해동방법에 따른 품질 특성을 평가한 결과 엄나무 햇순의 경우 상온 및 microwave 해동 시, 참죽 햇순의 경우 색도는 저온에서, texture는 상온해동에서 품질이 높게 평가되었으며, 해동방법에 따른 엄나무와 참죽 햇순의 기호도는 모두 microwave로 해동 시 가장 높게 평가되었다.