• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.548-551
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• 2001

A zero-voltage transition (ZVT) PWM boost PFC converter using a transformer to recover the resonant energy into the input voltage is proposed. The proposed converter reduces turn-off switching loss of the auxiliary switch. The resonant current of the auxiliary circuit is optimally reduced by the feed-forwarded input voltage. Moreover, the resonant energy of the auxiliary circuit is recovered into the load and input voltages. In this paper, the modes of converter operation are explained and analyzed, design guidelines are given, and experimental results of 1.2kW, 200kHz prototype system are presented.

• Nuclear Engineering and Technology
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• 제41권6호
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• pp.785-796
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• 2009

A KALIMER-600 concept which is a type of sodium-cooled fast reactor, has been developed at KAERI. It uses sodium as a primary coolant and is a pool-type reactor to enhance safety. Also, a supercritical carbon dioxide ($CO_2$) Brayton cycle is considered as an alternative to an energy conversion system to eliminate the sodium water reaction and to improve efficiency. In this study, a simplified model for analyzing the thermodynamic performance of the KALIMER-600 coupled with a supercritical $CO_2$ Brayton cycle was developed. To develop the analysis model, a commercial modular modeling system (MMS) was adopted as a base engine, which was developed by nHance Technology in USA. It has a convenient graphical user interface and many component modules to model the plant. A new user library for thermodynamic properties of sodium and supercritical $CO_2$ was developed and attached to the MMS. In addition, some component modules in the MMS were modified to be appropriate for analysis of the KALIMER-600 coupled with the supercritical $CO_2$ cycle. Then, a simplified performance analysis code was developed by modeling the KALIMER-600 plant with the modified MMS. After evaluating the developed code with each component data and a steady state of the plant, a simple power reduction and recovery event was evaluated. The results showed an achievable capability for a performance analysis code. The developed code will be used to develop the operational strategy and some control logics for the operation of the KALIMER-600 with a supercritical $CO_2$ Brayton cycle after further studies of analyzing various operational events.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.186-191
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• 2017

An integrated pressure-sensor system was developed using the sensor-conditioning processes, which resulted in the optimum sensitivity of the pressure-sensor through the signal amplification, noise reduction, and level shift. Due to the specified characteristics among the components, such as operation range, the sensor output was generally limited compared to the full scale of the reading when coupled with other parts. Devices fabricated exhibited comparable characteristics with higher pressure sensitivity to that of the pressure sensor without sensor-conditioning process. In this work, the sensor resolution was at least enhanced at least by 25% using the sensor-conditioning processes.

• 한국기계가공학회지
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• 제11권3호
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• pp.187-192
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• 2012

Recently, the electric device has been launching owing to the development of industry. That development also can maximize the efficiency of generator. The emergency rescue vehicle operation differs from ordinary vehicles in engine life and usage distances. For the application of this system, this research proposes the ways to operate the emergency rescue vehicle operations more efficiently. Currently, many power systems, especially motors, developed with a large output of power. It is possible to produce electricity in the engine room with enough space and to operate all equipment within the rating load capacity.

• 한국기계가공학회지
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• 제3권3호
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• pp.32-38
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• 2004

Recently, the system of high speed milling(HSM) is widely used for reducing the operation time and maximizing efficiency of work. The most research of high speed milling system is still leaves much to be desired. Specially the research of mass pocket high speed processing with high precision is the first and probably the last. So this paper showed mass pocket processing of high precision with a duralumin and then confirmed a cause of inferior goods through the CAD/CAM pattern simulation and experimentation. And this paper showed high speed processing system reduce the rate of inferior from this optimal pattern.

• 제어로봇시스템학회논문지
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• 제21권11호
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• pp.1076-1080
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• 2015

An inventory control system was developed for a distribution system consisting of a single multiproduct warehouse serving a set of customers and purchasing products from multiple vendors. Purchase orders requesting multiple products are delivered to the warehouse in a process. The receipt of customer orders by the warehouse proceeded in order intervals and in order quantities that are subject to random fluctuations. The objective of warehouse operation is to minimize the total cost while maintaining inventory levels within the warehouse capacity by adjusting the purchase order intervals and quantities. An adaptive model predictive control algorithm was developed using a periodic square wave model to represent the material flows. The adaptive concept incorporated a stabilized minimum variance control-type input calculation coupled with input/output stream parameter predictions. The effectiveness of the scheme was demonstrated using simulations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.184-187
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• 2005

The blade is an important part of rotating turbomachinery. The blade dynamic strength is of considerable importance as far as the reliability of operation and the life of the engine ate concerned. In this paper, blades are attached to a disk and coupled by means of damping wire. We assumes that the interfaces between the blade and disk dovetails are joined together, which means surface-to-surface contacts without friction. The damping wire is implemented using a beam element and temperature effect in the blade is neglected. Centrifugal forces ale applied by using an angular velocity to all elements in the system. The FEM results showed vibration characteristics in the blade disk system for the cases of a free-standing blade and blades with damping wire, respectively.

• 한국수자원학회논문집
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• 제44권12호
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• pp.1001-1013
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• 2011

이웃한 상수도시스템의 공급 가능지역이 중첩될 경우, 이들 시스템을 연계함으로써 경제성과 수질 조건을 만족시키는 조건별 용수공급체계를 구축하는 것이 필요하다. 용수수요 조건별 경제적 급수구역과 최적 펌프운영율을 산정하기 위하여 관망수리해석 모형(EPAnet)과 네트워크 최적화모형(KModSim)을 연계 하는 최적 네트워크모형을 개발하였다. 개발된 최적 네트워크 모형을 사등가압장, 구천댐 그리고 연초댐의 3개 상수원이 존재하는 거제지역 상수도시스템에 적용하고 2007년 운영 결과와 비교하는 방법으로 모형을 검정하였다. 최적 네트워크 모형의 적용성을 검토하기 위하여, 2011년 용수자료를 이용하여경제적급수구역변경에따른펌프운영및 수질의 적정성을평가 하였다. 평가결과본 모형은 수량, 경제성 그리고 수질을 모두 만족하는 최적해를 구하는 것으로 나타나 송배수계통간의 최적 설계 혹은 최적연계운영율을 구하기 위한 모형으로 활용이 가능하다.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제23권3호
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• pp.39-46
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• 2017

Purpose: Here is little information about China's operation department of general hospital in Korean medical architecture papers, which is inconvenient for scholars engaged in medical building research and comparison. Furthermore, Surgery is to provide patients with surgery and rescue sites, is an important technical department of the hospital, and then with the development of medical technology and people's trust in medical science, the role of the operating room will become increasingly important. Therefore, the purpose of this research is to analyze history, changes and definitions of the operating room and China's operation department of general hospital related laws and regulations for future research to provide effective analysis of data, and find shortcomings. Methods: This research was conducted according to the relevant laws, books, and papers of the operation department of Chinese general hospital. Results: At present hospital construction in China is in the period of rapid development and coupled with the growing medical technology, operating room layout and configuration is still in the continuous trial of continuous improvement stage. Overall, it requires more detailed guidelines to improve the quality of the operating room. Implications: Implications: It is expected that the research of this paper will provide an effective reference for the future research of the operation department of China General Hospital, which can promote and improve the work system of the operation department of China General Hospital.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.1974-1987
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• 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.