• Progress in Medical Physics
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• v.2 no.1
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• pp.17-28
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• 1991

Generally, it is an accurate radiation measurement technique for processors fo thermoluminescent dosimenters(TLDs) to characterize each element they use by producing element correction factors(FCFs). TLDs are classified into three groups such as reference. control, and field TLDs. Reference TLDs are used only for the production of ECFs for the control and field TLDs. They are kept locked in a safe place except when it is necessary to use a subset of them to produce ECFs for the control and field TLDs. The ECF of a given element is a measure of the response of the element relative to the mean response of an arbitrarily selected group of reference elements. As TLDs are used in the field, their relative responses to radiation might be decreased due to muliple readings and physical abuse. Therefore, the producditon of ECFs are performed initially and periodically during the field use. This element correction method provides an excellent tool to examine new TLDs and to monitor the reliability of old TLDs. This paper discuss the 10 step procedures developed to produce and examine ECFs.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.227-236
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• 2018

The focus control mechanism of the multi-purpose camera can be required for the better quality image acquisition. A good image acquisition through the hardware system including the optics and image sensor, has to be processed before the post correction for improvement of image quality. In the case of the high-resolution satellite camera, the focus control is not a necessity, unlike a normal camera due to a fixed optical system, but may be required due to various reasons. Although there is a basic focus control method using a motor for satellite electronic optical camera, a focus control method using thermal control can be a good alternative because of its various advantages in design, installation, operation, contamination, high reliability and etc. In this paper, we describe the design method and implementation results for the focus control mechanism using the temperature sensor and heater installed in the telescope structure. In the proposed focus control method, the measured temperature information is converted into temperature data by the Kalman filter and the converted temperature data are used in PI controller for the thermal focus control.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.815-824
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• 2012

Extractive distillation system can be used when the components to be separated have close boiling points or form azeotropes. Extractive distillation is one of the most important and widely used separation methods in chemical process industry. The main disadvantage of the distillation is its high-energy requirements. Thermally coupled distillation system (TCDS) can provide significant savings in energy consumption and capital cost over the operation of sequences based on conventional distillation column. Despite such advantages of the thermally coupled distillation system, the process is not widely used in industry because control and operation of the column are difficult. In this study, we propose several control schemes for thermally coupled distillation system to overcome the difficulties and make the column stable when the process is confronted with feed disturbances. Profile position control scheme shows best control performance among the proposed control schemes.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.382-385
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• 2008

박막형 태양전지 분야는 저가이고 가볍다는 특징을 가지고 있으며, 휘어지는 기판재를 적용하여 플렉서블 태양전지를 제조할 수도 있다는 장점을 가지고 있다. 본 연구에서 플렉서블 태양전지에 적합한 금속기판재를 제조하는 연구를 수행하였다. 일반적으로 기판재와 cell을 구성하는 반도체 층의 열팽창 거동 차이에 의한 열변형이 태양전지의 공정안정성에 영향을 주는 것으로 알려져 있었으며, cell을 구성하는 반도체 층과 열팽창 거동이 유사한 금속기판재의 적용이 필요하다. 이러한 특성을 쉽게 제어할 수 있는 금속기판재를 얇게 제조하기에 적절한 방법은 전주법이다. 전주법을 적용하여 조성 및 두께가 다른Ni 계 합금의 열팽창 거동을 TMA 장비를 사용하여 측정하였으며, 태양전지 제조에 사용되는 고온공정시 안정성 확보를 위하여 열처리후에 금속기판재의 열팽창 거동을 측정하였다. 그리고 전산해석tool 을 활용하여 가상의 CIS 플렉서블 태양전지 제조공정을 설정하고 고온공정온도에서 상온으로 냉각시 발생되는 층간 열변형 연구를 수행하였다. 그리고 플렉서블 태양전지용 기판재로 Ni 계 합금표면에 절연체인 $SiO_2$ 증착 연구를 수행하여 Fe-52Ni 합금에서 안정적인 절연층을 얻을 수 있었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.9-9
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• 1998

다목적 실용위성의 궤도전이 및 위성체 자세제어를 위한 추진시스템의 설계요소에는 구조적 안전성, 우주환경에서의 열제어를 위한 회로 및 구성하드웨어 설계, 연료계통 맥압강하를 위한 장치설계 및 추력기 배기가스 영향을 고려한 형상설계 등이 있으며, 설계검증을 위해 부분해석이 수행된다. 또한 발사환경과 우주 궤도환경에서의 추진시스템 성능평가를 위한 연제어계 기능시험, 압력인증시험, 청정도시험 및 내부/외부 누설시험이 수행된다. 본 논문에서는 추진시스템 설계 및 조립공정에 대해 기술하였고, 시험분석을 통해 시스템의 설계 및 조립공정상의 신뢰성을 검증 분석하였다.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.77-82
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• 2001

Thermal design for KOMPSAT-2 propulsion system has been performed. Overall design requirements and the constitution for propulsion system is described. To meet the thermal design requirements, both a primary and a redundant heater circuit, each with two thermostats placed in series, will protect each hydrazine-wetted components, even if one heater circuit fails to operate. Heater power is turned off if any one of these thermostats is opened at its higher setpoint. Thus, even if one thermostat is failed closed, the second thermostat will turn off the heater. All such components shall be insulated with MLI. Propulsion heater sizing based on the constant worst cold case condition is conducted through thermal analysis. All heaters selected for propulsion components operate to prevent propellant freezing satisfying the thermal requirements for the propulsion subsystem over the worst case average voltage, i.e. 25 volts.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.55-56
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• 2006

냉매 충전량과 이차유체의 입구조건은 $CO_2$용 열펌프시스템의 성능실험에서 중요한 제어변수이다. 따라서, 열펌프사이클의 적용과 난방성능 향상을 위해 제어변수의 특성을 조사하는 것이 필요하다. 본 논문에서, $CO_2$용 열펌프 사이클의 성능 실험은 여러 가지 냉매 충전량에서 이차유체 입구조건에 변화를 주어 수행 되었다. 실험결과, 난방COP는 냉매 충전량이 증가함에 따라 1158g의 냉매 충전량에서 최대가 되었다가 감소하는 경향이 나타나며, 이는 COP가 최대가 되는 냉매충전량이 존재함을 나타낸다. 또한, 난방성능은 가스쿨러내 이차유체의 질량유량의 증가에 따라 증가하였다. 가스냉각기내 2차유체의 입구은도가 $10^{\circ}C$에서 $40^{\circ}C$로 증가하면, 난방용량, 압축일량, 토출압력은 각각 -8.57%, -35.89%, 32.78%로 변화했으며, 증발기 2차유체의 입구 온도가 감소하였을 때 난방COP는 감소하는 경향을 보였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1006-1010
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• 2017

This paper describes the design and test of the thermal control and fire safety system for thermal control and the fire/explosion prevention of inside the compartment during the preparation and operation of the space launch vehicle at the launch pad. The system considered here is for the test launch vehicle which is being developed as part of the development of the Korean Space launch vehicle-II. This system applies the high pressure system based on the heritage of Naro launch vehicle. The selection of thermal control and fire safety system from high pressure and low pressure system is done in consideration of the characteristics of the launch pad gas supply system and the characteristics of launch vehicle, and the system configuration is also changed accordingly. As a result, it has been confirmed that the developed system satisfies the initial design conditions through the test. Moreover the system will be applied to the development of the Korean launch vehicle in the future.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.12
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• pp.1185-1192
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• 2012

The typical operating temperature of an automotive fuel cell is lower than that of an internal combustion engine, which necessitates a refined strategy for thermal management. In particular, the performance of the cooling module has to be higher for a fuel cell system because the temperature difference between the fuel cell and the surrounding is lower than in the case of the internal combustion engine. Even though the cooling system of an automotive fuel cell determines the operating temperature and temperature distribution of the fuel cell, it has attracted little research attention. This study presents the mathematical model of a cooling system for an automotive fuel cell system using Matlab/$Simulink^{(R)}$. In particular, a radiator model is developed for design optimization from the development stage to the operating stage for an automotive fuel cell. The cooling system model comprises a fan, pump, and radiator. The pump and fan model have an empirical relation, and the dynamics of the pump and fan are only explained by motor dynamics. The basic design study was conducted, and the geometric setup of the radiator was investigated. When the control logic was applied, the pump senses the coolant inlet temperature and the fan senses the coolant out temperature. Additionally, the cooling module is integrated with the fuel cell system model so that the performance of the cooling module can be investigated under realistic operating conditions.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.42-44
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• 1998

위성 시스템은 전력 분배, 자세 제어, 열 제어 및 임무 수행에 필요한 탑재체 지원과지상과의 명령 수신 및 측정데이터의 수집을 위해서 프로세서를 내장하고 있다. 임무 수행 및 시스템의 복잡성 여부에 따라서 하나의 프로세서만을 탑재하기도 하지만 여러 개의 프로세서를 탑재하여 기능에 적합하게 분배하여 운용하기도 한다. 아리랑위성은 3개의 프로세서사 탑재되며, 크게 나누어 원격 측정 명령계, 자세 제어계 그리고 전력계에 기능을 담당하게 된다. 하나 이상의 프로세서를 탑재하게 되면 프로세서간의 동기화가 요구되며 프로세서간의 정보 전달을 위해서 통신 채널이 필요하게 된다. 실제로 프로세서간의 동기화는 상호 통신에 있어서 기준 점을 제공하므로 매우 중요한 의미를 가진다. 본 논문에서는 아리랑위성의 동기화는 어떤 방식으로 설계되었으며, 어떻게 운영되는지에 대해 설명한다.