• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2528-2533
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• 2007

Thermoforming is one of the most versatile and economical processes available for the manufacturing polymer products. The drawback of thermoforming is difficult to get uniform thickness of final products. For the distribution of thickness strongly depends on the temperature distribution of sheet, the adjustment of heater power is very important In this paper, an optimization study for getting uniform temperature distribution was carried out using dual optimization steps. At first, the steady state optimal distribution of heater power is searched by numerical optimization to get uniform temperature of sheet surface. In the second step, time-dependent optimal heater inputs have been found out to decrease the temperature difference through the direction of thickness using Rseponse Surface Method and D-optimal method. The optimization results show that the time-dependent optimal heater power distribution gives acceptable uniform sheet temperature in the field of forming temperature..

• 한국유체기계학회 논문집
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• 제14권2호
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• pp.25-28
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• 2011

The control rod assemblies do freely fall into the reactor core by the gravity from the control rod drive mechanism. In order to achieve a rapid shutdown and control the reactor power, it is required to insert control rod assemblies as soon as possible. In this paper, we evaluated the drop time and flow characteristics caused around guide tube for SMART(System-integrated modular advanced reactor) control rod assembly. Numerical analyses are carried out with FLUENT program of computational fluid dynamics. This study results show that the drop time of the control rod assembly in the operating condition of SMART is more 20 percent rapidly than the drop time of the room temperature and ambient atmosphere condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2089-2092
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• 2002

The PID controller have the simple structure and show the comparatively good control performance. Crystal Grower(FF-CZ150) melt polycrystalline silicon at the temperature of about 1450$^{\circ}C$, then grow it into a single crystalline ingot. The automatic diameter control system of the Crystal Grower has a good performance with only PD control. But it contain the integrator in the plant which has a long time delay. In this paper, we show the secondary approximate model and applies time delay controller which has good performance for the plant with long time delay. It will be able to improve the response characteristic against a standard input and a load disturbance.

• 제어로봇시스템학회논문지
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• 제7권7호
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• pp.567-573
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• 2001

A real-time HVAC system is proposed which implements real-time control of thermal environment for virtual reality. It consists of a pair of hot and cold loops that serve as thermal reservoirs, and a mixing box to mix hot and cold air streams flowing if from loops. Their flow rates are controlled in real-time to meet a set temperature and flow rate. A cascade control algorithm along with gain scheduling is applied to the system and test results shows that the closed-loop response approached set values within 3 to 4 seconds.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2431-2433
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• 2001

Robust control for DC motor is needed according to the highest precision of industrial automation. It is a quite quality concerning to control temperature of single crystalline growth as it does when you get most of heat treating products. It is also important factor to control temperature when you make the A12O3(single crystalline) used to artificial jewels, glass of watches, heat resistant transparent glasses. Thus, it is a major interest to get the proper temperature in accordance with the time process while you are making mixture of oxygen and hydrogen to have the right temperature. In this paper, we will study of electrical valve positioning system for the gas mixture to improve the quality of products.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2001년도 춘계학술대회 발표논문집
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• pp.265-268
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• 2001

Robust control for DC motor is needed according to the highest precision of industrial automation. It is a quite quality concerning to control temperature of single crystalline growth as it does when you get most of heat treating products. It is also Important factor to control temperature when you make the A1203(sing1e crystalline) used to artificial Jewels, glass of watches, heat resistant transparent glasses. Thus, it is a major interest to get the proper temperature in accordance with the time process while you are making mixture of oxygen and hydrogen to have the right temperature. In this paper, we will study of electrical valve positioning system f3r the gas mixture to improve the quality of products.

• 한국산학기술학회논문지
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• 제8권6호
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• pp.1313-1318
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• 2007

다양한 곡률반경의 연속에 의하여 살 두께 차가 큰 jar50ml의 성형가공시간 단축과 품질향상을 위하여 금형을 급속 냉각시키면 void, 후로우 및 변형 등의 불량이 발생하게 된다. 제품내측과 외측의 온도조절을 충분히 할 수 있는 캐비티부와 코아부에 나선형 냉각회로 구조와 가열과 냉각을 자동 제어할 수 있는 시스템을 Jar금형에 적용함으로 우수한 품질과 생산성향상의 효과를 얻을 수 있다.

• 설비공학논문집
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• 제22권11호
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• pp.760-766
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• 2010

Excessive heat occurs during semiconductor manufacturing process. Thus, precise control of temperature is required to maintain constant chamber-temperature and also wafer-temperature in the chamber. Compared to an industrial chiller, semiconductor chiller's power consumption is very high due to its continuous operation for a year. Considering the high power consumption, it is necessary to develop an energy efficient chiller by optimizing operation control. Therefore, in this study, a semiconductor chiller is experimentally investigated to suggest energy-saving direction by conducting load change, temperature rise and fall and control precision experiments. The experimental study shows the cooling capacity of dual-channel chiller rises over 30% comparing to the conventional chiller. The time and power consumption in the temperature rising experiment are 43 minutes and 8.4 kWh, respectively. The control precision is the same as ${\pm}1^{\circ}C$ at $0^{\circ}C$ in any cases. However, it appears that the dual channel's control precision improves to ${\pm}0.5^{\circ}C$ when the setting temperature is over $30^{\circ}C$.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.872-875
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• 2004

In this paper, thermal response analysis of a temperature controlled three-axis accelerometer for high temperature environments with integrated micro-heaters and temperature sensors is investigated with finite element method (FEM) program, ANSYS and infrared thermal measurement systems. And availability to application fields from a viewpoint about short thermal response time is discussed. In this paper, the time of three-axis accelerometer for high temperatures becoming $300^{\circ}C$ by integrated micro-heaters and temperature sensors to reduce thermal drift characteristics was analyzed as a thermal response time of this device. The simulated thermal response time (time until SOI piezoresistors actually becomes $300^{\circ}C$) of three-axis accelerometer for high temperatures with ANSYS is about 0.6s, and measured result with infrared temperature measurement systems is about 0.64s. Experimental results using infrared thermal measurement systems agreed well with these theoretical results.

• 한국건축시공학회지
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• 제9권3호
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• pp.95-101
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• 2009

Constructing large-scale mat foundation mass concrete is increasing for the stability of building structure, because a lot of high rise building are being built in order to make full use of limited space. However, It is of increasing concerns that because limited placing equipments, available job-site and systems for mass concete placement in construction field do not allow to place great quantity of concrete at the same time in large scale mat foundation, consistency between placement lift can not be secured. And also, it is likely to crack due to stress caused by the difference of hydration heat generation time. To find out the solution against above problems, this study is to reconfirm the performance of normal concrete designed by mix proportion and super retarding concrete. The Fundamental test shows what happens if low heat proportioning and control method of setting time are applied at the job-site of newly constructed high rise building. The test result show that slump flow of concrete has been somewhat increased as the target retarding time gets longer, while the air content has been slightly decreased but this is no great difference from normal concrete. The setting time shows to be retarded as target retarding time gets longer, the range of retarding time increases. It is necessary to increase the amount of mix of super retarding agent in the proportion ration by setting curing temperature high since outdoor curing is about 6 hours faster than standard curing, which means the temperature of the concrete will be higher than the temperature of the surrounding environment, due to its high hydration heat when applying in a construction site. The compressive strength of super retarding concrete appears to be lower than normal concrete due to the retarding action in the early stage. However, as the time goes by, the compressive strength gets higher, and by the 28th day the strength becomes the same or higher than normal concrete.