• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.161-167
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• 2009

The liquid solar air conditioning system is introduced as an alternative solution to control air condition and to save electrical energy consumption. The heat and mass transfer performances of dehumidifier/regenerator in liquid solar air conditioning system are influenced by air and desiccant condition. The application of this system, the thermal energy from the sun and inlet air are unable to control, but operation parameter of other components such as pump, fan and sensible cooling unit are able to control. The equilibrium point of heat and mass transfer are the liquid desiccant and inlet air conditions, where, the heat and mass are not transferred between the liquid desiccant and vapor air. By knowing equilibrium point of heat and mass transfer, the suitable optimal desiccant conditions for certain air condition are funded. This present experiment study is investigated the equilibrium point heat and mass transfer in various air and desiccant temperature. The benefit of equilibrium point heat and mass transfer will be helpful in choose and design proper component to optimize electrical energy consumption.

• 전기학회논문지
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• 제64권11호
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• pp.1651-1657
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• 2015

In MHz operating wireless power transfer systems, skin- and proximity-effect losses in the transmitter and the receiver coils dominate the coil-to-coil efficiency of the system. A Litz-wire was regarded as a common solution for minimizing such Ohmic losses in high frequencies. In this paper, equivalent series resistances of 12 different cables including Litz-wire and copper tubing have been calculated and measured for a 6.78 MHz, 100W, 30 cm wireless power transfer system. It has been shown that the copper tubing has lower resistances compared to the Litz-wire in that frequency and a wireless power transfer system with the copper tubing was able to achieve much higher efficiency than a system using the Litz-wire. Calculations of the resistances and efficiencies were accomplished with analytical equations and those calculations were evaluated by experimental results.

• 설비공학논문집
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• 제19권5호
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• pp.418-425
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• 2007

The power consumption and heat generation in a chip increase as the components are miniaturized and the computing speed becomes faster. Therefore, suitable heat dissipation has become one of the primary limiting factors to ensure the guaranteed performance and reliable operation of the electronic devices. A pin-fin array which may be considered as a porous medium could be used as an alterative cooling system of the electronic equipment. The aim of the present study is to investigate the forced-convective heat transfer characteristics of pin-fin heat exchangers. Convective heat transfer through the pin~fin array is analyzed experimentally based on porous medium approach. The influence of the structure of the pin-fin array including the pin-fin spacing, the pin diameter and plate length on heat transfer characteristic is investigated and compared with the Previous analytical results and existing correlation equations. Nowadays, electronic and mechanical devices become smaller and smaller. In this sense, the main purpose of this study is to decide the optimum pin-fin arrangement to get similar heat transfer performance when the length of the existing cooling system is reduced as a half.

• 대한안전경영과학회지
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• 제19권4호
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• pp.317-322
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• 2017

When the heat flux on the heating surface following changing heat condition in the boiling heat transfer system exceeds critical heat flux, the critical heat flux phenomenon is going over to immediately the film boiling area and then it is occurred the physical destruction phenomenon of various heat transfer systems. In order to maximize the safe operation and performance of the heat transfer system, it is essential to improve the CHF(Critical Heat Flux) of the system. Therefore, we have analysis the effect of improving CHF and characteristics of heat transfer following the nanoparticle coating thickness. As the results, copper nanocoating time are increased to CHF, and in case of nano-coatings are increased spray-deposited coating times more than in the fure water; copper nanopowder is increased up to 6.40%. The boiling heat transfer coefficients of the pure water are increased up to 5.79% respectively. Also, the contact angle is decreased and surface roughness is increased when nano-coating time is increasingly going up.

• 대한기계학회논문집B
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• 제36권8호
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• pp.797-802
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• 2012

본 연구에서는 두 대의 히트펌프를 이용하여 $60^{\circ}C$의 난방 공급을 하는 경우에 대하여, 병렬운전을 할 경우의 성능과 직렬운전을 할 경우의 성능을 서로 비교함으로써, 직렬운전에 의한 성능 향상 가능성을 연구하였다. 두 경우의 성능을 공정하게 비교하기 위하여, 히트펌프를 구성하는 열교환기의 전열면적을 고정하였으며, 부하측 및 열원측의 입구 유량 및 온도 조건을 고정하였다. 또한, 보다 현실적인 결과를 위하여 열교환기 내 열전달 및 압력강하 특성을 고려하였다. 시뮬레이션 결과, 직렬운전 시스템의 난방성능계수가 병렬운전 시스템의 난방성능계수에 비해 본 연구의 시뮬레이션 조건 하에서 약 5% 향상 될 수 있음을 관찰하였다.

• 한국항해항만학회지
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• 제43권3호
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• pp.197-208
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• 2019

공 컨테이너 장치장의 사양, 취급 장비, 운영방법이 공 컨테이너 적하 시 발생할 수 있는 재취급 기대횟수에 미치는 영향을 연구하였다. 다수 선사의 다양한 유형의 공 컨테이너를 서로 분리된 공간에 저장한다면 저장 공간을 충분히 활용할 수 없고, 저장 공간의 활용도를 높이기 위해 여러 선사의 공 컨테이너를 혼적하여 함께 저장한다면 적하작업 중에 추가로 재취급이 발생할 수 있다. 한 베이에서 적하작업을 위하여 공 컨테이너를 인출하는 시점에 기대되는 재취급 횟수를 계산하기 위해 필요한 여러 가지 수식을 유도하였다. 트랜스퍼 크레인과 탑 핸들러를 취급 장비로 간주하여 다양한 인출 전략을 검토하였다. 장치장의 다양한 설계 및 운영 매개 변수가 재취급 횟수에 미치는 효과를 확인할 목적으로 수치실험을 수행하였다.

• 산업공학
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• 제17권2호
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• pp.233-241
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• 2004

The main subject to become a hub port is automation. The automated container terminal has already operated in advanced ports and it has been planned for the basic planning and operation design in domestic case. The key of automated container terminal is effective operation of both ATC(automated transfer crane) and AGV(automated guided vehicle) which is automated handling equipments. This is essential to productivity of automated container terminal. This study suggests the most optimal method of equipment operation in order to minimize loading time using each three types of effective ATC operation methods and AGV dispatching rules in automated container terminals. As the automated equipment operation causes unexpected deadlocks or interferences, it should be proceeded on event-based real time. Therefore we propose the most effective ATC operation methods and AGV dispatching rules in this paper. The various states occurred in real automated container terminals are simulated to evaluate these methods. This experiment will show the most robust automated equipment operation method on various parameters(the degree of yard re-marshaling, the number of containers and AGV)

• 전기학회논문지
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• 제65권1호
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• pp.73-80
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• 2016

The preliminary test for the dual mode plasma torch system was carried out to explore the operation properties in advance. The dual mode plasma torch system that is able to operate in transferred, non-transferred, or dual mode is very adequate for melting the mixed wastes including nonconductive materials such as concrete, asbestos, etc. since it exploits both the high efficiency of heat transfer to the melt in transferred mode and stable operation in non-transferred mode. Also, system operation including restarting is reliable and very easy. A stationary melter with a refractory structure was designed and manufactured considering the melting behavior of slags to minimize the refractory erosion. The power supply for the dual mode plasma torch system built with high power insulated gate bipolar transistor (IGBT) modules has functions for both current control and voltage control and is sufficient to suppress the harmonics during the operation of the plasma torch. The power supply provides two different voltages for transferred operation and non-transferred. It is confirmed that the operation voltage in transferred is always higher than non-transferred. The dual mode plasma torch system was successfully developed and is under operation for a melting experiment to optimize operation data.

• 대한토목학회논문집
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• 제32권6D호
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• pp.539-547
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• 2012

교통수단간 환승은 대중교통체계운영의 효율성 증대를 위해 반드시 필요한 것으로 무엇보다 중요한 것은 현실에 기초한 환승거점의 선정이라고 할 수 있다. 본 연구는 대중교통 이용자의 통행실태를 반영한 환승거점 입지선정 방향에 관한 연구로서 대구광역시를 대상으로 대중교통 이용객 1일 교통카드 사용내역 자료를 활용하여 환승통행패턴을 분석하고자 한다. 군집분석을 통해 이용객이 많은 정류소를 분류하고 환승통행량의 규모에 따라 그룹핑하여 판별분석을 실시하였다. 도출된 판별 함수를 이용하여 현재 시공 중인 대구시 도시철도 3호선의 환승통행량을 추정하고 환승센터 설치 가능지점을 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.509-511
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• 1989

In this paper the operation of a N2 laser using corona-preionization and capacitor transfer type excitation circuit is discussed. The laser tube is 24 cm in length and the distance between the electrodes is 1.5 cm. The charging voltage was kept constant 10 KV. This laser can be operated with a range of repetition rate 1 $\sim$ 30 Hz.