• Corrosion Science and Technology
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• 제7권1호
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• pp.16-21
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• 2008

A non-phosphorous program employing an alkyl epoxy carboxylate (AEC) has been successfully applied to petrochemical and other large industrial open recirculating cooling water systems. AEC is a patented non-phosphorous calcium carbonate scale inhibitor that has demonstrated better scale inhibition abilities than traditional organic phosphonates. In addition to its antiscalant properties, AEC inhibits carbon steel corrosion when used at high dosages. AEC can be combined with zinc to form a non-phosphorous program with very low levels of phosphate to provide an environmentally acceptable program. In actual applications, the total phosphate developed in the cooling system from cycling the makeup is below 1 ppm as $PO_4$. This level has complied with the highest standards of wastewater discharge limitations. The performance of two AEC/Zinc applications is reviewed. In both cases excellent corrosion and scale control were achieved with AEC/Zinc programs. One case history details the performance with a low hardness water (100 ppm calcium, as $CaCO_3$) operating at 8-10 cycles of concentration. The corrosive nature of the water and the long retention time of the system stressed both the corrosion and scale control capabilities of the program. The second case history demonstrates the performance of the program with a moderate hardness water (400-600 ppm calcium, as $CaCO_3$), but under harsh conditions of high temperature and low flow. The AEC/zinc combination has been found to be highly effective in controlling the corrosion of ferrous metals. AEC can provide good corrosion inhibition at high concentrations, while zinc is known to be an excellent cathodic inhibitor. The combination of the two inhibitors not only provides a synergistic blend that is effective over a wide range of operating conditions, but also is environmentally friendly.

• 접착 및 계면
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• 제9권3호
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• pp.27-33
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• 2008

무기계 킬레이트의 일종인 aluminum acetylacetonate (AlACA)를 점착제의 -COOH 당량비에 따라 0, 0.25, 0.5, 0.75, 1의 비율로 변화 시키고, 점착제는 acrylic acid의 함량을 3 wt%, 7 wt%, 10 wt%으로 변화를 시켜 그에 따른 경화거동을 살펴 보았다. 킬레이트의 함량이 증가하면서 가교 구조가 형성되고, 이에 따라 probe tack의 fibrillation이 줄어들고, peel strength도 줄어드는 경향을 보였다. SAFT의 경우 점착제의 acrylic acid 함량이 증가함에 따라 확연히 증가하였다. 본 연구 결과, aluminum acetylacetonate는 점착물성을 크게 변화시키지 않는 범위에서 점착제를 가교 시킬 수 있음을 확인하였다.

• 산업공학
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• 제22권2호
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• pp.104-115
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• 2009

The objective of the study is to evaluate the effectiveness of Crew Resource Management (CRM) training program for operators in the Main Control Room (MCR) simulator of APR-1400 Nuclear Power Plant. The experiments were conducted for two different crews of operators performing six different emergency operating scenarios during four-week period. Each crew consisted of the five operators: senior reactor operator, safety technical advisor, reactor operator, turbine operator, and electric operator. All crews (Crew A and B) participated in the training program for the technical knowledge and skills which were required to operate the simulator of the MCR during the first week. To verify the effectiveness of the CRM training program; however, only Crew A was selected to attend the CRM training after the technical knowledge and skills training. The results of the experiments showed that the CRM training program improved the individual attitudes of Crew A significantly. Team skills of Crew A were found to be significantly better than those of Crew B. The CRM training did not have positive effects on enhancing the individual performance of Crew A; however, as compared to that of Crew B. Implication of these findings was discussed further in detail.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.266-273
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• 2015

본 논문은 저장탄약의 신뢰성 보장을 목표로 수행한 저장탄약 신뢰성 평가 결과에서 얻어진 효과가 국방경영에 미치는 직접효과와 간접효과로 구분하여 산출하는 방법을 연구하고 실제 실시한 사업에 대해 재무효과를 산출하였다. 저장신뢰성평가 결과에 따라 수명연장, 제한사용, 정비, 폐기한 경우에 대한 직접적인 재무성과를 산출하는 방법을 각각 제안하였고, 전력지수 향상에 따른 재무성과 산출방법과 산업연관분석표에 의한 생산유발효과 및 고용유발효과를 산출하는 간접적인 재무성과 산출방법을 각각 제시하였다. 또한 연구된 산출방법론을 이용하여 2013년도에 수행한 저장탄약 신뢰성평가 사업에 적용하여 재무성과를 산출하였다. 그 결과 직접재무성과가 999.6억원, 전력향상에 의한 재무성과가 1206.1억원, 생산유발성과가 3,037.2억원으로 국방경영에 미치는 총 재무성과는 5,242,9억원으로 분석되었다.

• 항공우주시스템공학회지
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• 제13권1호
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• pp.38-46
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• 2019

가스터빈 엔진에 대한 엔진 진단기술에 대한 관심이 높아지고 있으며, 엔진 건전성 진단기술에 적용 가능한 정확한 엔진 성능모사 프로그램의 중요성은 점점 더 커지고 있다. 이를 위한 엔진 성능모사는 설계점 해석으로부터 시작하여 탈설계점 성능모사, 부분부하 성능모사를 정확하게 수행해야 할 필요가 있다. 이에 따라 본 연구에서는 2-스풀 분리 배기 방식 터보팬 엔진에 대한 엔진 시뮬레이션 프로그램을 개발하고 PW(Pratt & Whitney)사의 JT9D-7R4G 엔진을 해석하였다. 각 비행영역에서의 설계점과 탈설계점에서의 정상상태 성능모사를 수행하고, 최대이륙조건 설계점과 순항상태 설계점의 해석결과의 차이를 비교하였다. 또한 구성품 성능선도 축척법 중 하나인 Reynold's Correction의 효과를 분석하였다. 개발된 프로그램의 결과와 NPSS의 결과를 비교하여 프로그램을 검증하였다.

• 보건의료산업학회지
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• 제9권3호
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• pp.127-143
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• 2015

Objectives : This study is a quasi-experiment with a pre-post design and a nonequivalent control group performed from May 1 to June 2, 2013 to verify the effects of a simulation based education program on nursing students' self-confidence, and clinical performance ability. Methods : The subjects of the study were a total of 60 students in their fourth year of a nursing program at a university located in G city and they were assigned to an experimental group of 30 students and a control group of 30 students by convenience sampling. Results : After being offered education, self-confidence, and clinical performance ability were significantly more improved than before in each group. In the comparison of the two groups, the self-confidence (t=3.00, p=.004) and clinical performance ability(t=3.14, p=.003) of the experiment group were significantly higher than those of the control group. Conclusions : The results indicated that instructional methods using a simulation-based emergency care program should be adopted maximize the effects of advanced cardiopulmonary life support education.

• International Journal of Concrete Structures and Materials
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• 제6권3호
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• pp.165-176
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• 2012

The aim of this study is to assess the seismic performance of hollow reinforced concrete and prestressed concrete bridge columns, and to provide data for developing improved seismic design criteria. By using a sophisticated nonlinear finite element analysis program, the accuracy and objectivity of the assessment process can be enhanced. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), is used to analyze reinforced concrete and prestressed concrete structures. Tensile, compressive and shear models of cracked concrete and models of reinforcing and prestressing steel were used to account for the material nonlinearity of reinforced concrete and prestressed concrete. The smeared crack approach was incorporated. The proposed numerical method for the seismic performance assessment of hollow reinforced concrete and prestressed concrete bridge columns is verified by comparing it with the reliable experimental results. Additionally, the studies and discussions presented in this investigation provide an insight into the key behavioral aspects of hollow reinforced concrete and prestressed concrete bridge columns.

• 한국게임학회 논문지
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• 제19권6호
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• pp.71-82
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• 2019

본 논문은 상용 게임 엔진인 언리얼 엔진이 지원하는 네트워킹 기능과 사용자 제작 IOCP 게임 서버의 성능을 게임 내의 변수 전달 관점에서 비교 분석하였다. 이를 위하여 언리얼 엔진 4를 기반으로 3D 게임과 IOCP 게임 서버를 자체 제작하였다. 그리고 코드 변조 게임 해킹 프로그램의 메모리 수정을 방지하기 위해서 게임 변수 난독화 프로그램에 관하여 고찰한다. 이를 위하여 언리얼 엔진 솔루션 인 SCUE4 안티-치트 Solution을 활용하여 메모리 수정을 하는 것을 방지하는 방법을 연구하고 성능 트레이드 오프에 대한 분석을 수행한다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권4호
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• pp.559-563
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• 2001

The effects of feeding a mannan oligosaccharide (Bio-Mos) from 0 to 3 g/kg diet and vaccination program on 1- to 35-day performance (growth and feed efficiency), metabolizable energy, nitrogen utilization and carcass composition of meat chickens were investigated. A general vaccination program was used against IB, IBD and ND with half of the birds per diet receiving a booster dose of IB and ND vaccines at 12 days of age. Dietary supplementation of Bio-Mos (BM) did not influence body weight gain, feed efficiency and nutrient utilization. The highest dietary BM (3 versus 1.5 or 0 g/kg) increased carcass abdominal fat and reduced the proportion of drumstick in the carcass of meat chickens. The booster dose reduced the performance of birds. It was concluded that the addition of BM to the diet of chickens did not significantly influence the performance and nutrient utilization of meat chickens.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.345-348
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• 2008

The computer-aided performance simulation can reduce periods for development of products and cut down on the cost comparing with former trial-and-error procedures. This study has developed a simulation program for a vehicle thermal management system integrating an engine cooling system and an air conditioning system considering interactions and arrangement of air side heat exchangers such as power steering oil cooler, air-cooled transmission oil cooler, condenser, and radiator. The program may be also used for the system performance analysis according to the configuration of the engine coolant side heat exchangers such as water-cooled transmission oil cooler, EGR cooler, and heater core. Experiments utilizing an environmental wind tunnel has been conducted to assess the performance of the system according to the arrangement of air side heat exchangers. Some modification of the coolant loop layout can enhance the heat core performance up to 7% according to the results of the simulations.