• Journal of Welding and Joining
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• 제14권2호
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• pp.71-78
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• 1996

In order to rpovide proper SMT design criteria in a systematic way, a mathematical formulation has been developed to predict the configuration of the solder fillet formed between the gullwing type lead and rectangular pad. Effects of SMT design parameters such as the solder volume and pad dimension on the solder profile are investigated using the FEM that calculates the 3D configuration by minimizing the energy due to surface tension and gravity in the equilibrium state. Design criteria of QFP and SOP are illustrated by plotting the acceptable range of the solder volume with respect to the length and width ratios of the pad and lead. The results show that the acceptable design range increases with increase in the pad length and width. The pad length has more significant effects on design criteria compared with the pad width, and Bond number can be utilized to predict the joint quality.

• 한국분무공학회지
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• 제16권4호
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• pp.186-194
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• 2011

This study performed the numerical analysis of the internal nozzle flows including cavitation phenomena by using the automated body-fitted grid generator and the multi-fluid model. The effect of grid refinement and the validation of multifluid model were investigated using four computational meshes under two test conditions. The mesh #3 was chosen as the optimum which can reduce the computational time and have good prediction ability to identify the cavitation region simultaneously. In addition, the computed results using multi-fluid model were compared with the reference experimental observations and numerical simulation results using homogeneous equilibrium model. From the distribution of volume fraction and velocity field, the multi-fluid model predicted the internal nozzle flows well when the liquid quality parameters were selected as $1.0{\times}10^{12}$ for initial number density and 25 ${\mu}m$ for bubble diameter.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.827-832
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• 2009

Exergy is the amount of reversible work obtainable when some matter is brought to a state of thermodynamic equilibrium with ambient. This exergy is availability or useful work induced from carnot cycle, and this can calculate the irreversible loss work which occurs within any thermal or power cycle. The exergy ratio is the value of exergy divided by enthalpy of ambient reference, where the quality of energy or enthalpy in substances is evaluated by exergy ratio. Exergy is very important in optimal design method of thermal system or each component, and the value of exergy at given state is calculated by equation. Here, designer can easily understand and find the value of enthalpy because enthalpy is graphically drawn in chart, however exergy did not. In this paper, exergy and exergy ratio of air were drawn on temperature-entropy chart, and we wish to this chart is a help to design, analysis and education.

• 환경위생공학
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• 제15권4호
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• pp.14-19
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• 2000

This study was carried out to get efficient of nutrient removal and wastage sludge production minimized effects on the treatment of slaughterhouse wastewater using aerobic curtain biological film contact process. As a results of biofilm attachment experiment aggravation of water quality due to excessive biofilm showed after every 15 days of operating times. The concentration of BOD and COD in the influent were 2500~3000mg/L and 1700~2100mg/L , respectively. The average BOD and CoD were 9mg/L and 17mg/L , respectively. The result of this experiment was wastage sludge did not almost generated and the removal efficiency of nutrients were kept equilibrium.

• 한국가구학회지
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• 제27권2호
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• pp.91-95
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• 2016

This study was conducted to investigate the relationship between water absorption (or hygroscopic property) and growth rate of rubra oak (Quercus rubra) from 5 different origins of seed (Carleton, Simcoe, Chatham, Bancroft, Unknown). Water absorption at cross section of Quercus rubra was $0.43{\sim}0.92g/cm^2$ and the property was not related with growth rate. Overall equilibrium moisture content of rubra oak were 11.35~11.56% and 15.15~15.83% at $40^{\circ}C$ with 75% and 90% relative humidities, respectively. There was no relationship between growth rate and moisture content(hygroscopy) in rubra oak. Based on the results, Rubra oak can be classified as a low hygroscopic wood grade, and thus might be a good raw material for furniture productions owing to its superior dimensional stability.

• Nuclear Engineering and Technology
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• 제32권1호
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• pp.17-33
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• 2000

A mechanistic model based on wall-attached bubble coalescence, previously developed by the authors, was extended to predict a vow high critical heat flux (CHF）in highly subcooled flow boiling, especially for high mass flux and small tube diameter conditions. In order to take into account the enhanced condensation due to high subcooling and high mass velocity in small diameter tubes, a mechanistic approach was adopted to evaluate the non-equilibrium flow quality and void fraction in the subcooled water flow boiling, with preserving the structure of the previous CHF model. Comparison of the model predictions against highly subcooled water CHF data showed relatively good agreement over a wide range of parameters. The significance of the proposed CHF model lies in its generality in applying over the entire subcooled flow boiling regime including the operating conditions of fission and fusion reactors.

• 산업경영시스템학회지
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• 제22권51호
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• pp.211-220
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• 1999

The purpose of this study is the necessity of collaboration, equilibrium or the differences of examination items about certification system which is focused on products, such as KS, formal approval, and ISO 9000 family, QS 9000, etc, for Quality management system. We make expert group control this problem. Also we make examination items to be united. And the differences of certification body and personnel necessary is dissolved by proper instruction. Examination process and corrective maintenance should be improved by clarity, fairness and reliability. Problems through preparation for certification and certified company should be focused on reform of consciousness of top management and continuous instruction. And desirable solution for mutual certification problem and others should be found by information interchange system of international cooperation.

• 공업화학
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• 제29권5호
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• pp.630-634
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• 2018

본 연구는 폐플라스틱 열분해유(WPPO) 유분의 품질향상의 일환으로 유분 중에 함유된 파라핀 성분의 회수를 회분 병류 4회 평형추출에 의해 검토했다. 원료로서는 WPPO를 단증류하여 회수한 유출온도 $120-350^{\circ}C$의 유분을, 용매로서는 소량의 물이 첨가된 디메틸포름아마이드(DMF) 용액을 각각 사용했다. 평형추출 횟수(n)와 파라핀 성분의 탄소수가 증가할수록 추잔유 중에 함유된 파라핀 성분의 농도는 증가했다. n = 4에서 회수된 추잔유 중의 $C_{12}$, $C_{14}$, $C_{16}$, $C_{18}$ 파라핀 성분의 농도는 원료의 농도에 비해 약 1.2, 1.5, 1.6, 1.8배 각각 높았다. 파라핀 성분의 회수율(추잔유 중의 잔류율)은 n가 증가할수록 급격히 감소하고 탄소수가 큰 성분일수록 급격히 증가했다. 또한, 원료 중에 함유된 전체 파라핀 성분($C_7-C_{24}$)에 대한 n = 1 - 4에서의 회수율을 예측 가능했다. 본 연구 결과를 통해 회수한 추잔유는 신재생에너지로 사용이 가능할 것이라 기대된다.

• 한국가금학회지
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• 제40권3호
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• pp.223-234
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• 2013

Poultry industry is abounding day by day as it engrosses less cost of investment per bird as compared to large animals. Poultry have the most copious genomic tool box amongst domestic animals for the detection of quantitative trait loci (QTL) and marker assisted selection (MAS). Use of multiple markers and least square techniques for mapping of QTL affecting quality and production traits in poultry is in vogue. Examples of genetic tests that are available to or used in industry programs are documented and classified into causative mutations (direct markers), linked markers in population-wide linkage disequilibrium (LD) with the QTL (LD markers), and linked markers in population wide equilibrium with the QTL (LE markers). Development of genome-wide SNP assays, role of 42 K, 60 K (Illumina) and 600 K (Affymetrix$^{(R)}$ Axim$^{(R)}$) SNP chip with next generation sequencing for identification of single nucleotide polymorphism (SNP) has been documented. Hybridization based, PCR based, DNA chip and sequencing based are the major segments of DNA markers which help in conducting of MAS in poultry. Economic index-marker assisted selection (EI-MAS) provides platform for simultaneous selection for production traits while giving due weightage to their marginal economic values by calculating predicted breeding value, using information on DNA markers which are normally associated with relevant QTL. Understanding of linkage equilibrium, linkage dis-equilibrium, relation between the markers and gene of interest are quite important for success of MAS. This kind of selection is the most useful tool in enhancing disease resistance by identifying candidate genes to improve the immune response. The application of marker assisted selection in selection procedures would help in improvement of economic traits in poultry.

• 한국항해항만학회지
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• 제29권6호
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• pp.589-593
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• 2005

연안 준설퇴석물을 열처리, 생물침출공정을 이용한 중금속처리, 중화처리 등의 다양한 방법으로 전처리한 재료를 이용하여 연안해수에 함유된 질산염의 흡착특성에 대한 실험실적 연구를 수행하였다. 전처리된 퇴적물의 흡착평형시간은 생물침출-열처리 퇴적물이 17분으로 가장 빨랐으며 생물침출-중화-열처리 퇴적물과 생물침출퇴적물이 각각 25분. 27분으로 황토와 열처리 황토에서의 3,3분, 32분 보다 빠르게 흡착되는 것으로 평가되었다. 시험된 재료들에 대한 흡착공정은 Freundlich 등온흡착식으로 해석할 수 있었으며, 전처리한 퇴적물의 흡착속도가 황토에 비해 빠름을 알 수 있었다. 질산염의 흡착량은 퇴적물과 열처리 퇴적물에서 각각 2.l2, 2.19 mg NO3-N/g 으로 가장 많았으며 열처리 등으로 전처리된 퇴적물은 연안해수의 수질개선을 위한 흡착재로서 활용 가능한 것으로 평가되었다.