• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 춘계 학술대회논문집
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• pp.153-158
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• 2007

Since the introduction of Nanoimprint in the mid-1990s, Nanoimprint lithography, a low-cost, non-convential method, has been the dominant lithography technology that guarantees high-throughput patterning of nanostructures. Based on the mechanical embossing mechanism, Nanoimprint lithography creates the nanopatterns on the polymer material cast on the substrate. In essence, the process needs nanofabrication equipment for printing with the adequate control of temperature, pressure and control of parallels of the stamp and substrate. This article introduce the possibility and reality of the thermal control on the hot plate using a CFD code. Numerical computation has been conducted for assessing the feasibility of a hot plate($120{\times}120\;mm2$). PID control is adopted to ensure high temperature uniformity in several zones. Parallel experiments have also been performed for verifying thermal performance. Not only show the results the optimum number of thermocouples related to controllers but also suggest that the thermal simulation using a CFD code would be an alternative method to design and develop the thermal control equipment in the financial aspect.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2836-2844
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• 2000

Thickness control of hot-rolled strips has become an important issue in recent years because of the need for improving the quality of the hot-rolled strip. In this study, a modifying method of rolling force set-up with consideration of spread was developed to improve the thickness uniformity at the finishing rolling units in hot rolling. Through the analysis of real production data it was found that the accuracy of the rolling force determined from the finishing mill set-up (FSU) model dominantly governed the thickness uniformity in rolled plates at the front. Based on this analysis , several examples were selected to calculate the spread of rolled plate using three dimensional rigid thermo-viscoplastic finite element program. FE analysis results were used to train the neural network system that can predict the spread hot-rolled plate and the rolling force was modified based on the predicted value of spread. The modified rolling forces were closer to the measured rolling force so it can be expected that the accuracy of thickness uniformity of hot-rolled plate will be improved.

• 한국의류산업학회지
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• 제7권2호
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• pp.247-251
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• 2005

In this the study, the effects of the manufacturing process conditions on the properties Thick and Thin Diameter yarns(TTD yarns) prepared with hot plate device in the draw winder were determined. Physical properties including wet shrinkage, tenacity and elongation of the samples were measured and thick and thin effect was analysed with the evenness tester. The results were as the follows: There was little change the wet shrinkage of the TTD yarns in the range of $70^{\circ}C{\sim}80^{\circ}C$ of $R_1$ temperature(lower hot cylinder) with the same Hot Plate(H/P) temperature, but the wet shrinkage of the TTD yarns decreased 5-10% when $R_1$ temperature was $90^{\circ}C$. The wet shrinkage of the TTD yarns decreased with the H/P temperature at the same temperature of $R_1$. There was little effect of $R_1$ and H/P temperature on the tenacity of TTD yarns. The elongation of TTD yarns increased with $R_1$ temperature at the same H/P temperature. The elongation of TTD yarns increased little bit for the first time and then decreased above that temperature with increasing H/P temperature at the same $R_1$ temperature. The thick and thin effect on the TTD yarns was obvious in $110^{\circ}C$ of H/P temperature regardless of $R_1$ temperature, while there was no thick and thin effect on the TTD yarns in $140^{\circ}C$ of H/P temperature.

• 한국정밀공학회지
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• 제19권8호
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• pp.180-186
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• 2002

Hot Plate is the major unit that it used to remove damp of wafer surface, to strength adhesion of photoresist (PR) and to bake coated PR in FAB process of semiconductor. The badness of Hot Plate (HP) has directly influence upon the performance of wafer, it is necessary to guarantee the performance of HP. In this study, a reliability evaluation system has been designed and developed, which is to measure and to estimate thermal uniformity and flatness of HP in range of temperature 0~$250^\circC$. This system has included the techniques which measures and analyzes thermal uniformity using infrared thermal vision, and which compensates measuring error of flatness using laser displacement sensor For measuring flatness, a measurement stage of 3 axes are developed which adapts the precision encoder. The allowable error of this system in respect of thermal uniformity is less $than\pm0.1^\circC$ and in respect of flatness is less $than\pm$1mm . It is expected that the developed system can measure from $\Phi200mm\;(wafer 8＂)\;to\;\Phi300mm$ (wafer 12＂) and also can be used in performance test of the Cool Plate and industrial heater, etc.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 추계학술발표대회 개요집
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• pp.91-93
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• 2005

The purpose of this study is to evaluate effects of stiffener configuration welded to the plate on the fatigue strength. Nominal stress and hot spot stress for the stiffened plate under pure bending condition were evaluated using FEA and experiment and fatigue test for each specimen was performed. For S and SD type, the fatigue strength increase with a decrease in the nominal stress and hot spot stress. D type with doubler plate was found to have the lowest value of nominal and hot spot stress for a given condition. However its fatigue strength was smaller than the others.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.347-349
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• 2009

Unmanned helicopters are needed in various fields such as monitoring system, agriculture and forest fire. Swash plate is a essential part for exact driving of unmanned helicopter. And it is usually produced by machining. In this research, hot forging process of upper swash plate has been studied to improve proof stress against repeated loading of the product. In the forming analysis, design parameters such as effective stress, effective strain and distribution of damage have been considered in the hot forging.

• 한국태양에너지학회 논문집
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• 제34권6호
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• pp.49-56
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• 2014

Research about hybrid solar air-water heater that can make heated air and hot water was conducted as a part of improving efficiency of solar thermal energy. At this experiment, ability of making heating air and hot water was investigated and compared with traditional solar air heater and flat plate solar collector for hot water when air or liquid was heated respectively. Comparing hybrid solar air-water heater that used in this experiment to other solar air heater studied already, it has a lower efficiency at same mass flow rate. Air channel structure, fin's shape and arrangement in the air channel result in these difference then the ability of air heating need to be improved with changing these thing. In case of making hot water, performance was shown as similar with traditional system although the air channels were established beneath absorbing plate. But the heat loss coefficient was shown higher value by installing of air channel. Also the performance of hot water making was shown lower value at same liquid mass flow rate with traditional flat plate solar collector for hot water. So the necessity of performance improvement at lower mass flow rate of each heating medium can be confirmed.

• 소성∙가공
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• 제18권4호
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• pp.290-295
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• 2009

The roll gap set-up in the finishing mill is one of the most important technologies in the hot plate rolling process. As the target thickness can be obtained by the correct set-up of the roll gap, improving the roll gap set-up technology is very critical for plate thickness accuracy. The main cause of thickness variation in hot plate mills is the non-uniform temperature distribution along the length of the slab. The objective of this study is to adjust the roll gap set-up for the thickness accuracy of plate in hot rolling process considering top-end temperature drop. Therefore this study has concentrated on determining the correct amounts of thickness variation according to top-end temperature drop and roll gap to compensate thickness variation. The control method of roll gap set-up which can improve the thickness accuracy was proposed. The off-line simulation of compensated roll gap significantly decreases top-end thickness variation.

• 한국주조공학회지
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• 제29권3호
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• pp.144-149
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• 2009

In this study, we investigated optimum condition of cooling plate method to obtain semi-solid AM100A Mg alloy with fine and globular morphology. AM100A Mg alloy were hot extruded at $380^{\circ}C$ extrusion temperature under extrusion ratio of 25 : 1 and ram speed of 2.4 mm/sec. Vickers hardness test, optical microscopy, scanning electron microscopy, and image analyzer were performed to identify the optimum conditions of cooling plate method. Optimum conditions of cooling plate method to fabricate semi-solid AM100A Mg alloy with fine and globular microstructures were achieved at a pouring temperature of $602^{\circ}C$ and the angle of cooling plate of 60 degree.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.261-266
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• 2000

Temperature variation during silicon wafer baking is mainly due to natural convection caused by temperature difference between silicon wafer and upper plate. Several cases are tested and calculated numerically to improve temperature uniformity. The temperature difference and velocity magnitude in the flow cell is reduced for a small gap between the wafer and upper plate because the natural convection force is suppressed in the small space. The uniform temperature distribution can be obtained with controling the incoming flow distribution from the upper plate. An alternative method is the adiabatic wall condition on the upper plate to maintain the temperature uniformity within $0.3^{\circ}C$ on the water plate.