• 한국의류산업학회지
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• 제1권1호
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• pp.12-17
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• 1999

The actual clothing conditions were surveyed to diagnose clothing condition of collegians in the view point of adaptation to the thermal environment in fall. Then, clothing climate, physiological responses, and subjective sensation were investigated through wearing trials on human subjects in climatic chamber based on the results from the survey. Factors to evaluate validity of clothing condition were clothing weight, clothing climate, physiological responses of human body, and subjective sensation. Adaptability of this research to thermal environment was compared to the results of Toda's and Duno's of Japan, Chung's results of Korea rural area, and Winslow's clo value. The standard values for wearing trials were values at comfortable zone, such as $32{\pm}1^{\circ}C$ of temperature and $50{\pm}10%$ of humidity inside clothing, $36.5{\sim}37.3^{\circ}C$ of ear temperature and $32.2{\sim}34.3^{\circ}C$ of mean skin temperature. Clothing weight per body surface area was 680.9 $g/m^2$ in male and 526.7 $g/m^2$ in women. Cold resistance ability of collegians was superior to Japanese and American, and similar to rural male in Korea. According to the examination of clothing adaptability with clothing weight from the investigation on physiological responses and the actual clothing conditions survey, following were found. Temperature inside clothing ($29.8{\sim}32.3^{\circ}C$) was normal, and humidity inside clothing (32.2~54.8%) was at comfortable zone. Mean skin temperature was at its comfortable zone. Therefore, 615 $g/m^2$ in male and 525 $g/m^2$ in female were a desirable wearing condition.

• Wind and Structures
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• 제30권4호
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• pp.325-338
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• 2020

In this paper, the improvement of the anti-snow performance of a high-speed train (HST) is studied using the unsteady Reynolds-Averaged Navier-Stokes simulations (URANS) coupled with the Discrete Phase Model (DPM). The influences of the proposed flow control scheme on the velocity distribution of the airflow and snow particles, snow concentration level and accumulated mass in the bogie cavities are analyzed. The results show that the front anti-snow structures can effectively deflect downward the airflow and snow particles at the entrance of the cavities and alleviate the strong impact on the bogie bottom, thereby decrease the local accumulated snow. The rotational rear plates with the deflecting angle of 45° are found to present well deflecting effect on the particles' trajectories and force more snow to flow out of the cavities, and thus significantly reduce the accretion distribution on the bogie top. Furthermore, running speeds of HST are shown to have a great effect on the snow-resistance capability of the flow control scheme. The proposed flow control scheme achieves more snow reduction for HST at higher train's running speed in the cold regions.

• Journal of Advanced Marine Engineering and Technology
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• 제39권4호
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• pp.432-436
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• 2015

본 연구에서는 해수를 활용하여 수동적으로 냉각되는 폴리머 히트싱크의 열성능을 전산적으로 탐구한다. 폴리머 히트싱크는 폐열회수를 위한 열전생성기의 저온면의 냉각모듈로 제안되었고, 상세한 수치연구를 위해 3차원 전산유체역학 모델링이 수행되었다. 폴리머 히트싱크의 기본 소재로 polyphenylene sulfide (PPS)와 pyrolytic graphite (PG)가 선택되었고, 전산연구는 다양한 휜 수와 휜 두께에서 PPS와 PG 히트싱크의 성능을 결정하고, 이 결과는 알루미늄 (Al)과 티타늄 (Ti) 히트싱크와 비교된다. 연구결과는 PG 히트싱크가 Ti 히트싱크 보다 3~4배 열성능이 우수함을 보이는데, 이 결과는 Ti 히트싱크보다 더 우수한 PG 히트싱크의 열확산에 기인한 것으로 보인다. 연구결과에 의하면 PG 히트싱크의 열성능에 대한 휜 수 증가의 효과가 PPS와 Ti 히트싱크 경우와는 상반됨을 보이는데, 이는 휜 수 증가에 대한 열확산, 표면적 증대, 유동저항의 상관관계로 설명이 가능하다.

• 접착 및 계면
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• 제12권4호
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• pp.117-124
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• 2011

본 연구는 보호콜로이드로 PVA를 사용한 PVAc 에멀젼 폴리머와 VAE 에멀젼 폴리머 블렌드에 관한 것으로 보호콜로이드로 사용된 PVA는 블렌드 전의 각각의 에멀젼 폴리머 필름과 블렌드 후의 필름에서도 연속상으로 존재하였다. 이는 블렌드를 구성하는 입자사이에서 뛰어난 접착력을 예상하게 한다. Tg가 서로 다른 에멀젼 폴리머 블렌드는 중요한 관심 대상이며 PVAc/VAE 에멀젼 폴리머 블렌드는 이 중 간단하면서도 또 다른 뛰어난 연구 방향을 제시하였다. 혼합 결과, PVAc 증가에 따라 신율이 저하되었고, PVAc 제조에 사용된 가소제가 혼합물의 Tg에 영향을 미쳐 PVAc 가소제의 VAE 에멀젼 폴리머으로의 이행으로 인하여 VAE 에멀젼 폴리머의 Tg를 저하시켰고, 인장강도 및 내열성, 접착력에서 두 혼합물의 상승효과가 나타났다.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.734-743
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• 2017

In order to investigate the swelling behavior and fuel-cladding interaction mechanism of U-10Zr alloy metallic fuel at very low burnup, an irradiation experiment was concisely designed and conducted on the China Mianyang Research Reactor. Two types of irradiation samples were designed for studying free swelling without restraint and the fuel-cladding interaction mechanism. A new bonding material, namely, pure aluminum powder, was used to fill the gap between the fuel slug and sample shell for reducing thermal resistance and allowing the expansion of the fuel slug. In this paper, the concise irradiation rig design is introduced, and the neutronic and thermal-hydraulic analyses, which were carried out mainly using MCNP (Monte Carlo N-Particle) and FLUENT codes, are presented. Out-of-pile tests were conducted prior to irradiation to verify the manufacturing quality and hydraulic performance of the rig. Nondestructive postirradiation examinations using cold neutron radiography technology were conducted to check fuel cladding integrity and swelling behavior. The results of the preliminary examinations confirmed the safety and effectiveness of the design.

• 한국자원식물학회지
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• 제25권1호
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• pp.72-79
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• 2012

Vaccinium oldhami Miq. is a Korean native tree, which is deciduous and shrub tree with broad leaf. It grows 1~4m in height generally. Ecologically, this tree grows well in shady place even in barren soil. Also, the tree has resistance to cold and dry, which tend to form a little community. This research investigates quantitative morphological characteristics of leaf and fruit among the V. oldhami in South Korea and then considers its relationship on the basis of raw data among the 10 populations. This study will give us invaluable information about growing conditions, reasonable management and breeding by selection of V. oldhami in South Korea. The main results obtained from this study are summarized as follows; Leaf size of Mudeung population was larger than other populations. Naebyeon population was smaller in size of the leaf than other populations. Anmyeondo population was larger in fruit characteristics compared with other populations and Deogyu population was the smallest among populations. According to cluster analysis based on the leaf and fruit morphological characteristics, the natural V. oldhami populations were classified into four groups such as the first group of Kumo population, the second group of Mudeung population, the third group of Anmyundo, Daedun, Doolyun population and the fourth group of the other five populations.

• 미생물학회지
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• 제50권4호
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• pp.334-344
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• 2014

백김치로부터 분리된 유산균으로 제조된 요구르트를 냉장 보관하는 동안 미생물학적 및 물리화학적 특성 및 Helicobacter pylori ATCC 43504에 대한 항균 활성을 조사하였다. 요구르트의 유산균수, 적정산도, 점도 및 총 고형물 함량은 사용된 균주에 따라 유의적인 차이가 있었으나, 발효 직후부터 7일간 저장하는 동안 유의할만한 차이 없이 일정하게 유지되었다. Lactobacillus brevis BK11과 Lactobacillus paracasei BK57 균주로 발효시킨 요구르트는 인공 위액과 담즙액에 대해 다른 균주들 보다 강한 저항성을 보였다. 한편, 이들 유산균으로 제조한 요구르트 내에 존재하는 유산 생성량은 상대적으로 높았으므로 H. pylori와 혼합 배양한 결과 대조구에 비해 유의적인 항균 효과를 나타낸 것으로 추정되었다. 특히, L. brevis BK11에 의해 발효시킨 요구르트에 의해선 AGS 세포에 대한 H. pylori의 부착을 억제할 수 있었고, 이들이 생산하는 urease의 활성을 낮추는데도 효과적이라는 것을 확인하였다.

• 한국작물학회지
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• 제49권2호
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• pp.148-153
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• 2004

The Hessian fly, Mayetiola destructor (Say), is known to be one of the major insect herbivores of wheat worldwide. In order to provide molecular events on interactions of the NIL with H21 and larvae of Hessian fly biotype L, the TaCR1 gene, Triticum aestivum cytokinin repressed 1, was isolated through the suppression subtractive hybridization, which was constructed using stems of the NIL with H21 at 6 days after infestation as tester and stems of the recurrent parent Coker797 without H21 at 6 days after infestation as driver. Transcript levels of TaCR1 mRNA in the NIL with H21 were highest at 6 days after infestation but in the Coker797 without H21 until 8 days were similar with those of non-infested plants. Expression of the TaCR1 gene was decreased at early time and then recovered after wounding or $H_2O$$_2$ treatment as well as 6-BAP treatment. Transcripts levels of the TaCR1 gene was changed after MeJA, SA, ethephone, or ABA treatment. In drought treatment, the TaCRl gene were increased at early stage of stress and then decreased at late stage. Expression of the TaCRl gene was continued to decrease through 24 h in the cold treatment. Although the TaCRl gene is increased through infestation in NIL with H21, further study was required to elucidate a role on resistance against larvae of Hessian fly. However, the TaCR1 gene could be used as marker gene on response of plants against abiotic stresses as well as application of plants with several hormones.

• Current Research on Agriculture and Life Sciences
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• 제5권
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• pp.75-80
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• 1987

냉동발효(醱酵)빵 제조에 사용되는 경질(硬質) 밀가루의 이화학적(理化學的) 성질과 straight no-time method로 조제한 반죽의 동결안정성(凍結安定性)을 검토(檢討)하였다. 밀가루는 수분이 14.0%, 회분(灰分)이 0.48% 정도였고 단백질이 13.15%, 건조 gluten이 13.43%였다. Farinograph성적은 반죽의 development time이 5.5분, 흡수율(吸水率) 62%였고, amylograph성적상의 최고점도(最高粘度)는 500BU정도였다. Extensigraph의 특성중(特性中) 신장저항성(伸張抵抗性)은 시간이 경과할수록 증가하였고, 신장성(伸張性)은 감소(減少)하였다. 이상(以上)의 이화학(理化學)이 성질(性質)로 미루어 공시(供試)밀가루는 제(製)빵에 아주 적합하였다. 동결저장기간과 발효시간이 발효력(醱酵力)에 미치는 영향을 고려할 때, 반죽온도를 $20^{\circ}C$로 조정하는 것이 반죽의 냉동장해(冷凍障害)를 억제하고 냉동안정성(冷凍安定性)을 유지하는데 효과적(效果的)이었다.

• 한국추진공학회지
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• 제24권6호
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• pp.143-154
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• 2020

액체로켓엔진의 추진제 공급시스템의 각 요소와 전체 시스템에 대한 보편적 모델에 실험계수를 적용한 수학적 모델링 기법을 소형 액체로켓엔진을 모사한 수류 시험 장치를 통한 실험 결과로부터 검증하였다. 유체저항요소와 펌프의 압력 변화에 대한 예측을 수행하였으며 예측 정확도 향상을 위해 구성요소 모델링에 대하여 실험계수를 적용하였다. 이를 위해 각 구성요소에 대해 유동의 지배방정식이나 이미 알려진 경험식을 기반으로 실험계수의 도출 방안에 대하여 정리하였으며 사용한 상용품의 실험계수를 제시하였다. 모델링을 통한 예측 결과는 실험 데이터와 비교적 잘 일치하였다. 실험데이터와의 검증을 통해 시뮬레이션의 정확도에 영향을 미치는 인자에 대해 분석하고 시스템 해석의 정확도 향상 방안에 대하여 제안하였다.