• 한국가스학회:학술대회논문집
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• 한국가스학회 2006년도 추계학술발표회 논문집
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• pp.196-199
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• 2006

• Journal of the Korean Wood Science and Technology
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• 제21권1호
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• pp.51-58
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• 1993

The phenol resorcinol formaldehyde resin (PRF) adhesives which are curing at ambient temperature for structural purposes were synthesized. A PRF resin is produced according to the two-stage reaction system. In first stage, a low-condensed resol or methylolated phenol were prepared from phenol by reaction with a formaldehyde in alkaline condition. The molar ratio of phenol to formaldehyde was 1.0~1.4. And in second-stage, resorcinol was added to combine with the methylol group of a low-condensed resol(R/P molar ratio 0.3). The glue-joint strength, pot-life and workability of this synthetic PRF resin were superior to conventional ambient temperature setting adhesives such as oilic urethane or water based polymer-isocyanate resin for wood adhesives.

• 한국방재학회 논문집
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• 제4권2호
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• pp.53-59
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• 2004

본 연구는 집중호우 시에 발생하는 맨홀뚜껑의 비산(飛散)현상의 원인을 수리모형과 수치모형(SWMM)을 사용하여 밝힌 연구이다. 대규모 간선에서 써차지 흐름의 급격한 수두상승 현상에 대해 수치모형과 수리모형 결과가 매우 잘 일치하였다. 맨홀 뚜껑이 비산 하는 현상의 원인은 펌프장의 게이트 조작이나 간선의 막힘 등으로 발생하는 써차지 흐름에 따른 압력전파에 의해 기인하는 맨홀 내 잔존 압축공기괴의 맨홀에서의 팽창 분출에 의한 것으로 나타났다.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1638-1649
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• 2020

In the case of a severe accident in a Light Water Reactor, the issue of late release of fission products, from the primary circuit surfaces is of particular concern due to the direct impact on the source term. CsI is the main iodine compound present in the primary circuit and can be deposited as particles or condensed species. Its chemistry can be affected by the presence of molybdenum, and can lead to the formation of gaseous iodine. The present work studied chemical reactions on the surfaces involving gaseous iodine release. CsI and MoO₃ were used to highlight the effects of carrier gas composition and oxygen partial pressure on the reactions. The results revealed a noticeable effect of the presence of molybdenum on the formation of gaseous iodine, mainly identified as molecular iodine. In addition, the oxygen partial pressure prevailing in the studied conditions was an influential parameter in the reaction.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1397-1405
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• 2009

In recent decades, exergy analysis has been holding spotlight as a useful tool in the design, assessment, optimization, and improvement of energy system. This paper presents the results of the energy and exergy analysis of a steam turbine cogeneration system for industrial complex using two efficiency concepts of conventional one and exergetic one. In order to obtain the destroyed exergy of each component, mathematical analysis is conducted by using exergy balance and the second law of thermodynamics, according as the parameters are changed, such as the ratio of returned process steam, process steam supplied, temperature and pressure of boiler and power. The computer program developed in this study can determine the efficiencies and exergy destroyed at each component of cogeneration system. As a result of this study, a component having the largest destroyed exergy was boiler. And closed and opened feedwater heater had the lowest one. The affects to the cogeneration system due to the variation of process steam flow and return rate of condensed water is shown that the total electric power efficiency(${\eta}_E$) is decreased as increasing the return rate of condensed water under constant process steam flow. As the boiler pressure is increased for the more production of electricity, the efficiency of cogeneration system was decreased.

• 한국산학기술학회논문지
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• 제21권11호
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• pp.427-434
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• 2020

본 연구는 생산비 절감을 위하여 양돈사료 내 당밀 대체 Condensed molasses soluble (CMS)를 육성비육돈 사료 내에 첨가 급여하였을 때, 생산성 및 육질에 미치는 영향을 평가하기 위하여 수행하였다. 공시동물은 평균 체중 27.3±1.78 kg의 교잡종(LY×D) 육성돈 160두를 공시하여, 4개 처리구에 완전임의배치로 공시하였다. 시험사료는 시판 육성비육돈사료 급여구(무첨가구)와 시판사료에 각각 당밀 3 % 첨가구(MOL 3.0), CMS 1.5 % 첨가구(CMS 1.5), CMS 3 % 첨가구(CMS 3.0)로 설계하였다. 각 처리구별 시험사료와 물은 70일 동안 자유채식을 실시하였다. 생산성을 분석한 결과, 당밀과 CMS첨가구에서 대조구 대비 사료섭취량이 유의하게 높은 것이 관찰되었으며, CMS 3 % 첨가에 의해 대조구 대비 종료체중과 일당증체량이 유의하게 개선되는 효과를 확인하였다(p<0.05). 사료요구율은 당밀 및 CMS 첨가 그룹에서 대조구와의 통계적 유의한 차이는 관찰되지 않았다. 사양시험 종료 후 등심부위의 육질을 평가한 결과에서 보수력, 가열감량, pH 모두 처리구간에 유의적인 차이는 관찰되지 않았다. 본 연구의 결과는, 육성비육돈 사료 내 CMS 3%의 첨가급여는 육질의 저하 없이 생산성 개선 효과를 가지며, 양돈 사료 내 당밀 대체제로써 CMS의 활용 가능성을 시사한다.

• 공업화학
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• 제7권1호
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• pp.91-100
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• 1996

사염화실리콘에 에틸알콜의 수분함랑을 2.5, 5.0, 7.0wt.%로 달리하여 축중합된 에틸실리케이트(CES : condensed ethylsilicate)용액들을 합성하였다. 용액의 졸-겔 전이 거동 조사를 위하여 시간경과에 따른 용액의 부피, 밀도, $SiO_2$ 함량, 본성점도 및 수평균분자량변화를 측정하였으며, 용액의 고분자 형상을 본성점도와 수평균분자랑 관계로부터 간접적으로 알아보았다. 에틸알콜의 수분함량을 7.0wt.%로 하여 합성한 CES-3는 수분함량이 2.5wt.%, 5.0wt.%인 CES-1, CES-2와 다른 졸-겔 전이 거동을 보였으며, 복합산화물계 요업재료 제조시에 TEOS의 가수분해 속도를 조절하기위하여 부분가수분해 시킨 PHT(Partially Hydrolysed TEOS)와 유사한 거동을 보였다. Mark-Hawink가 제시한 $[{\eta}]=K\bar{Mn}^{{\alpha}}$식에 의한 CES 및 PHT의 고분자형상은, 지수 ${\alpha}$값이 0.53~0.84로 용액 모두 선상 혹은 사슬상 고분자로 나타났으며, 이상의 졸-겔 거동과 고분자형상에 대한 비교 실험 결과로부터 CES-3는 PHT와 매우 유사한 물성을 가지고 있어 복합산화물계 요업재료의 원료로 사용될수 있는 가능성이 높은것으로 나타났다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.46-53
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• 2011

Water is continuously produced in polymer electrolyte membrane fuel cell (PEMFC), and is transported and exhausted through polymer electrolyte membrane (PEM), catalyst layer (CL), microporous layer (MPL), and gas diffusion layer (GDL). The low operation temperatures of PEMFC lead to the condensation of water, and the condensed water hinders the transport of reactants in porous layers (MPL and GDL). Thus, water flooding is currently one of hot issues that should be solved to achieve higher performance of PEMFC. This research aims to study liquid water transport in porous layers of PEMFC by using pore-network model, while the microscale pore structure and hydrophilic/hydrophobic surface properties of GDL and MPL were fully considered.

• Asian-Australasian Journal of Animal Sciences
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• 제33권1호
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• pp.177-185
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• 2020

Objective: The study was conducted to establish a relationship between inclusion level of Vachellia tortilis (V. tortilis) leaf meal and time spent on different behavioral activities by finishing pigs. Methods: A total of forty-eight male Large White×Landrace finishing pigs with a mean (±standard deviation) body weight of 63.8±3.28 kg aged 14 wks were assigned to individual pens in a completely randomized design. Pigs were fed on diets containing 0, 30, 60, 90, 120, and 150 g/kg dry matter of V. tortilis leaf meal ad libitum with fresh water provided throughout the trial. There were eight pigs in each experimental diet. The behavior of pigs was observed for three wks twice a wk from 0600 to 1800 h using six closed circuit television cameras. Results: Increasing levels of V. tortilis leaf meal caused a linear decrease (p<0.05) in time spent eating, lying down and the number of visit to the feeder. Time spent standing and biting objects increased linearly (p<0.05) with increasing inclusion level of V. tortilis leaf meal. The was a negative linear relationship (p<0.05) between condensed tannins versus time spent eating, lying down and number of feeder visits. Condensed tannins showed a positive linear relationship (p<0.05) with time spent standing and biting objects. Neutral detergent fiber caused a linear decrease (p<0.05) in number of feeder visits, time spent eating, time spent standing. Conclusion: Inclusion level of V. tortilis leaf meal reduces time spent eating, lying down and the number of feeder visit while prolonging time spent standing and biting of objects. Condensed tannins and dietary fiber are among nutritional factors affecting behavioral activities displayed by finishing pigs.

• Animal Bioscience
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• 제34권2호
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• pp.205-212
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• 2021

Objective: The purpose of present study was to investigate the effects of condensed molasses fermentation solubles (CMS) on lactation performance, rumen fermentation, nutrient digestibility, and serum parameters of dairy cows. Methods: A total of 75 healthy Holstein cows with the same parity (milk production = 35±2.5 kg, body weight = 570±28 kg) were randomly selected and divided into 5 groups. One group served as control group (CON; no CMS), whereas the other 4 groups were CMS1 (accounted for 1% of the diet), CMS2 (2%), CMS3 (3%), and CMS4 (4%). All cows were fed regularly three times each day at 0800, 1600, and 2400 h. Cows received diet and water ad libitum. The experiment lasted for 60 days. Results: Results showed that the dry matter intake, milk yield, and protein of CMS2 were maximum and higher (p<0.05) than CMS4. The ruminal pH was observed less than 6 in CMS3 and CMS4 groups. No noticeable difference of microbial protein was found between CON and CMS2 groups, while the microbial protein in these groups was higher (p<0.05) than CMS3 and CMS4 groups. The apparent digestibility of dry matter, organic matter, and crude protein in CMS2 group was higher (p<0.05) than CMS3 and CMS4 groups. Compared to CMS3 and CMS4 groups, the CMS2 group increased (p<0.05) the serum concentrations of immunoglobulin G and immunoglobulin M on d 60. Conclusion: Therefore, it is practicable that CMS substitutes for a part of concentrates in lactating cows' diets, but higher addition of CMS (more than 3% of the diet) could decrease production performance of dairy cows as seen in the present study.