• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.128.2-128.2
• /
• 2010

For stationary 1kW-class fuel cell systems to be used widely, it is essential to achieve dramatic improvements in system durability as well as cost reduction. In order to address this engineering challenge, it is important to develop innovative technologies associated with BOP components. According to this background, in 2009, the Korean Government and "Korea Institute of Energy Technology Evaluation and Planning(KETEP)" launched into the strategic development project of BOP technology for practical applications and commercializations of stationary fuel cell systems, named "Technology Development on Cost Reduction of BOP Components for 1kW Stationary Fuel Cell Systems to Promote Green-Home Dissemination Project". The objectives of this project are to develop fundamental technologies to meet these requirements, and to improve the performance and functionality of BOP components with reasonable price. The project consortium consists of Korea's leading fuel cell system manufacturers, BOP component manufacturers which technologically specialized, and several research institutions. This paper is to provide a summary of the project, as well as the achievements made through the 1st period of the project(2009~2010). Several prototypes of BOPs - Cathode air blowers, burner air blowers, preferential oxidation air blowers, fuel blowers, cooling water pumps, reformer water pumps, heat recovery pumps, mass flow meters, valves and power conditioning systems - had been developed through this project in 2010. As results of this project, it is expected that a technological breakthrough of these BOP components will result in a substantial system cost reduction.

• Journal of Magnetics
• /
• v.16 no.2
• /
• pp.120-124
• /
• 2011

The design of an air compressor-driving quadratic linear actuator in a fuel cell BOP system is studied using orthogonal techniques. The approach utilizes an orthogonal array for design of 'experiments', i.e. the scheme for numerical simulations using a finite element method. Eco-friendly energy is increasingly important due to the depletion of fossil fuels and environmental pollution. Among the new energy sources, fuel cell is spotlighted as renewable energy because it produces few dusts. The air compressor performance is directly related to the efficiency of the fuel cell BOP system has high power consumption. In this paper, an optimized technique using an orthogonal matrix is applied to the design problem to improve the performance of quadratic linear actuator.

• Nuclear Engineering and Technology
• /
• v.55 no.6
• /
• pp.1974-1987
• /
• 2023

The load-following operation of small modular reactors (SMRs) requires accurate prediction of transient behaviors that can occur in the balance of plants (BOP) and the nuclear steam supply system (NSSS). However, 1-D thermal-hydraulics analysis codes developed for safety and performance analysis have conventionally excluded the BOP from the simulation by assuming ideal boundary conditions for the main steam and feed water (MS/FW) systems, i.e., an open loop. In this study, we introduced a lumped model of BOP fluid system and coupled it with NSSS without any ideal boundary conditions, i.e., in a closed loop. Various methods for coupling boundary conditions at MS/FW were tested to validate their combination in terms of minimizing numerical instability, which mainly arises from the coupled boundaries. The method exhibiting the best performance was selected and applied to a transient simulation of an integrated NSSS and BOP system of a SMART. For a transient event with core power change of 100-20-100%, the simulation exhibited numerical stability throughout the system without any significant perturbation of thermal-hydraulic parameters. Thus, the introduced boundary-condition coupling method and BOP fluid system model can expectedly be employed for the transient simulation and performance analysis of SMRs requiring daily load-following operations.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.8
• /
• pp.1090-1094
• /
• 2009

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1993.10a
• /
• pp.1-2
• /
• 1993

• Proceedings of the Korea Database Society Conference
• /
• 1999.06a
• /
• pp.469-475
• /
• 1999

고객의 주문에 따라 제품을 설계하고 생산하는 수주생산업체의 생산일정계획을 수립하는 데는 널리 알려진 자재소요량 기법이 적합하지 않다. BOP는 이러한 수주생산업종의 생산일정계획에 효과적으로 사용될 수 있는 기본 자료이며, 본 논문에서는 이것을 이용한 효과적인 유한능력 생산일정계획절차를 제시한다. 아울러 이를 기반으로 앞으로 계속되어야 할 연구 주제 및 현재 일정계획절차의 개선방향에 대하여 설명한다.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 1999.03a
• /
• pp.469-475
• /
• 1999

고객의 주문에 따라 제품을 설계하고 생산하는 수주생산업체의 생산일정계획을 수립하는 데는 널리 알려진 자재소요량 기법이 적합하지 않다. BOP는 이러한 수주생산업종의 생산일정계획에 효과적으로 사용될 수 있는 기본 자료이며, 본 논문에서는 이것을 이용한 효과적인 유한능력 생산일정계획 절차를 제시한다. 아울러 이를 기반으로 앞으로 계속되어야 할 연구 주제 및 현재 일정계획절차의 개선방향에 대하여 설명한다.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.04a
• /
• pp.539-544
• /
• 2000

The purpose of this study is to develop the mechanical anchorage, namely MAB-BOP (Mechanical Anchorage of 90$^{\circ}$ Hooked Bars with BOlt nad Plate) of the beam-column joint in precast concrete framed structures. Six specimens simulating typical interior beam-column joints were tested to investigate the mechanical characteristics of MAB-BOP. Of primary interest was the measurement of the slip of the anchored bar. Th load-slip curve obtained from this test were used to compare the mechanical performances of the different anchoring methods. Based on the test results, it was found that MAB-BOP showed sufficient anchoring strength capacity compared to 90$^{\circ}$ hooked bar method. So, MAB-BOP can be used as the anchoring methods of the reinforcing bars in PC beam-column joint.

• Journal of Periodontal and Implant Science
• /
• v.42 no.6
• /
• pp.212-216
• /
• 2012

Purpose: The aim of this study was to evaluate the relationship between maternal periodontal disease and the health status of newborns using Apgar scores. Methods: One hundred pregnant women with periodontal disease were included in the case series and 100 pregnant women without periodontal disease were placed in the control group, respectively. The periodontal parameters of bleeding on probing (BOP), clinical attachment loss (CAL), probing depth (PD), birth weight, and Apgar scores were recorded in both groups. T-tests and Pearson's correlation coefficient were used to determine the birth weight odds ratio to analyze the relationship between the periodontal parameters of BOP, CAL, and PD on the one hand and an Apgar score of less than 7. An unpaired Student's t-test was used to analyze differences in means between the case and control groups using SPSS ver. 13. Results: The means of the ages, periodontal pocket depths, attachment loss, areas with BOP, Apgar score in the first 5 minutes and infant birth weight exhibited statistically significant differences between the case and control groups. The ratio of an Apgar score of <7 to periodontal disease was 3.14; the ratio of low birth weight risk in mothers with periodontal disease to that in mothers without periodontal disease was 2.74. Pearson's correlation coefficient revealed a significant correlation between the infant birth weight and BOP, CAL, and PD of the mother. In addition, there was a significant correlation between the Apgar score and BOP, CAL, and PD and also between the Apgar score and infant birth weight. Conclusions: The results of this study showed a significant relationship between periodontal disease and infant birth weight; in addition, there was a significant relationship between the periodontal indexes of BOP, CAL, and PD on the one hand and the Apgar score on the other.

• The korean journal of orthodontics
• /
• v.28 no.2 s.67
• /
• pp.255-268
• /
• 1998

This study was investigated to assess the difference of facial height and occlusal plane inclination between normal occlusion group and class II malocclusion group. The subjects consisted of 50 normal occlusion (male 25, female 25) and 50 class II(male 25, female 25) malocclusion patients. All subjects are adult. lateral cephalogram was taken with standard method traced, and digitized for each subjects. The computerized statiscal analysis was carried out with SPSS program. The results were as follows 1. In class II malocclusion group, variables significant different from normal occlusion group were as follows ; SN-FOP, FH-BOP, MP-BOP, AB-BOP, AB-FOP, Facial plane-BOP, FP-FOP 2. In class II malocclusion group, the posterior facial height -especially posterior lower facial height-was significantly smaller than normal occlusion group.(P<0.05) 3. In class II malocclusion group, the angles between occlusal plane and upper and lower incisor, the angle between upper molar and bisected occlusal plane were significantly larger than those of normal occlusion group. (P<0.05) 4. L1 to Mandibular plane (mm) was a unique factor of occlusal plane position that showed significant difference in class II malocclusion group. 5. The correlation between overbite and occlusal plane inclination existed in class II malocclusion group, but the correlation didn't exist in normal occlusion group.