• 한국해양공학회지
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• 제7권2호
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• pp.121-130
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• 1993

A study off riction welding of high speed steel(SKH 51) bar for blade side to carbon steel(STC 3)bar for shank side was carried out experimentally through tensile test, hardness test, microstructure, and acoustic emission (AE) test. So, this paper deals with optimizing the welding conditions and the real-time quality (strength) evaluation of friction weleded joints by acoustic emission technique. The results obtained are summarized as follows: (1) For friction welded joints of SKH 51to STC 3 steel bars, the total upset (U) increases linearly with an increase of heating time (t sub(1)). (2) The determined optimum welding conditions are heating time (t sub(1)) 7-9 sec, upsetting time (t sub(2)) 5 sec, heating pressure(P sub(1)) 12 kg sub(f)mm supper(2), upsetting pressure (P sub(2)) 15 kg sub(f) mm supper(2) and rotating speed (n) 2, 000 rpm, resulting in a computed relationship between the tensile strength of the joint .sigma. (kg sub(f) mm supper(2)) and the heating time t sub(1) (sec) as the following. sigma.=2.39t sub(1)

• Journal of Welding and Joining
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• 제23권2호
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• pp.52-58
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• 2005

This study was carried out to investigate the effect of bonding temperature and heating rate on transient liquid phase diffusion bonding of Ni-base superalloy. The heating rate was varied by $0.1^{\circ}C$/sec, $1^{\circ}C$/sec, $10^{\circ}C$/sec to the bonding temperatures $1100^{\circ}C,\;1150^{\circ}C,\;1200^{\circ}C$ under vacuum. As bonding temperature increased, maximum dissolution width of base metal increased, but a dissolution finishing time decreased. The eutectic width of insert metal in the bonded interlayer decreased linearly in proportion to the square root of holding time during isothermal solidification stage. The bonding temperature was raised, isothermal solidification rate slightly increased. As the heating rate decreased and the bonding temperature increased, the completion time of dissolution after reaching bonding temperature decreased. When the heating rate was very slow, the solidification proceeded before reaching bonding temperature and the time required for the completion of isothermal solidification became reduced.

• 소성∙가공
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• 제19권5호
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• pp.277-282
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• 2010

Magnesium alloy has been known as lightweight material in automobile and electronic industry with aluminum alloy, titanium alloy and plastic material. Friction welding is useful to join various metals and nonferrous metals that are difficult to join by such as gas welding, resistance welding and electronic beam welding. In this study, friction joining was performed to investigate mechanical properties of Mg alloy with 20mm diameter solid bar. Also the optimal joining conditions for its application were determined on the basis of tensile test, and hardness survey. The joining parameters were chosen as heating pressure, heating time, upsetting pressure, and upsetting time. Heating and upsetting pressure were executed under the range of 10~40MPa and 20~80MPa, respectively. From the experimental results, optimal joining conditions were determined as follows; rotating speed=2000rpm, heating pressure=35MPa, upsetting pressure=70MPa, heating time=1sec, upsetting time=5sec. Also the hardness of jointed boundary showed as HV50 which was similar to that of base metal at the optimal condition, and it was supposed that zone of HAZ was 8mm. Finally two materials were strongly mixed at interface part to show a well-combined microstructure without particle growth or any defect.

• 전기학회논문지P
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• 제57권4호
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• pp.408-411
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• 2008

As to this research is new structure of the semiconductor substrate heating apparatus. The fast thermoresponsive according to the direct heating structure of the heating plate layer adhering closely to the floor side of a substrate and the fast heat loss minimization can be accomplished. Moreover, the contact area of the sheath heater, which is the heating plate layer built-in heating apparatus, is increased, so that it has more heating valid area. For this, it adheres closely to the substrate, in which the photosensitive film is coated and the heating plate layer, adhering closely to the floor side of a substrate the mica layer which adheres closely to the floor side of the upper heating plate layer in order to minimize an insulation and heat loss, and the lower part of the mica layer and it is comprised of the floor plate layer. The heating plate layer forms the continued groove portion over the floor side whole. The sheath heater for heating a substrate is inserted with the groove portion and the heating plate layer is comprised. It is confirmed that by using the new substrate heating structure, the temperature change of the heating plate against the time is observed. Then, there is the electric power saving effect of about 40% in comparison with the existing method.

• 한국식생활문화학회지
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• 제23권1호
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• pp.26-32
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• 2008

: In this experiment, three samples of oils were used. These oils were hydrated soybean oil, pure soybean oil and regular soybean oil. Oil was used after heating at $235-240^{\circ}C$ every four hours term and total heating hours was 16 hours. The physio-chemical analysis and sensory evaluation were performed on these oils. The hydrated soybean oil showed lower acid, peroxide and carbonyl value than the other two oils (p<0.05 or p<0.001). The other two oils were more affected in rancidity than the hydrated soybean oil. In color test, whereas L value lowed during the heating time, a and b value increased during the heating time. The tendency of high L value and low b value in a long-time heating was more apparant on the pure soybean oil and the regular soybean oil than on the hydrated soybean oil (p<0.05). In sensory evaluation, color and rancidity order increased during the heating time. The hydrated soybean oil showed color and rancidity order than the other two oils. In overall quality test, the pure and regular soybean oil that had been used for 12 and 16 hour were not preferable. The hydrated soybean oil that had been used for 16 hour were not preferable. In sensory evaluation, the hydrated soybean oil, the pure and regular soybean oil did not show a apparent difference, although the hydrated soybean oil had a little better scores on the overall quality.

• 가정과삶의질연구
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• 제7권1호
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• pp.79-95
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• 1989

Household energy consumption had influenced on the ecological system's environment. Household's exceeding energy consumption requires the development of resources and the risk. Thus this study attempted to find the household heating management, The purpose of this study was to investigate the household's heating management in the area of district heating. The major finding were; 1) The district heating was accepted positively and the benefit of this system was utilized very well in the household. 2) Variances in heating energy consumption was explained by the family size at October, residential period at October and November and the temperature of living room at October, November and December. 3) Compaired to central heating apartment, the low heating expenditure was characterize in the household of 4-5 persons, nuclear family at October, moderated heating control, using extra heating facilities at November. An in the December, that household was that husband has graduated college, temperature of the living room was some cold, and house wives was the full-time homemaker.

• 한국군사과학기술학회지
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• 제8권2호
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• pp.77-87
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• 2005

The thermomechanical characteristics were evaluated for 17-4PH stainless steel widely used in supersonic airframe subjected to both aerodynamic loading and heating. The thermomechanical tests were conducted under both elevated temperature and rapid heating condition from $1^{\circ}C/sec\;to\;28^{\circ}C/sec$. The thermomechanical behaviors under rapid heating were compared with those of elevated temperature after 1/2 hour exposure in terms of yield stress to investigate the influence of heating rates. A heating rate-yield temperature parameter was suggested for rapid heating based on time-temperature parameters, and master yield stress curve was obtained by using these parameters. The experimental results and methodology from this study can be used as basic engineering data when designing supersonic vehicle structures subjected to aerodynamic loading and severe heating environment.

• 한국조리학회지
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• 제19권3호
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• pp.209-217
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• 2013

본 연구에서는 소스나 수프 등의 기본재료가 되는 홍합 육수를 제조함에 있어서 홍합의 각종 영양 성분을 적절하게 이용하여 홍합 육수를 만들고자 하였다. 수분함량은 가열시간이 증가함에 따라 유의적(p < 0.05)으로 낮아졌다. 색도측정 결과, L값은 MS1(35.48)이 가장 높았고, a값도 MS1(-2.39)이 가장 높았으며, b값은 MS5(-9.49)가 가장 높았다. pH는 MS5가 6.56으로 가장 낮아 가열시간이 증가 시 시료 간의 유의적(p < 0.001)인 차이를 보이며 낮아졌다. 당도는 MS3이 $4.03^{\circ}Brix$로 가장 높았고, MS1이 $3.37^{\circ}Brix$로 가장 낮았다. 염도는 MS1이 0.71%로 가장 낮았고, 가열시간이 증가 시 시료간의의 유의적인(p < 0.001) 차이를 보이며 염도가 높아졌다. 홍합육수의 특성차이검사 결과, 육수의 외관, 투명도, 비린냄새, 비린맛, 짠맛은 가열시간 증가 시 강하게 평가되었다. 감칠맛은 MS4가 4.33으로 가장 강하게 평가되었다. 홍합육수의 기호도 검사 결과, 맛, 전체적인 기호도 항목에서는 MS3이 가장 좋게 평가되었다. 이상의 결과로 볼 때, 가열시간 증가로 홍합육수의 기호도가 대체적으로 좋게 평가되었으며, 홍합육수 제조 시 가열시간이 15분일 때 기호도가 상승되는 것을 알 수 있었다.

• 설비공학논문집
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• 제7권2호
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• pp.171-183
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• 1995

Generally, among many kinds of shading devices such as venetian blind, sunscreen, louver and curtain, venetian blind is using widely because the mechanism is so simple and easy to use solar insolation by controlling the slat angle. Analysis of time dependent heat transfer through the window with venetian blind is very important in order to use it effectivly. Therefore, in this study, theoretical thermal analysis method was developed to analyze time dependent heat transfer through a double pane window with and without venetian blind, and was made one module of TRNSYS(A Transient Simulation Program)program. By this way, it was analyzed that how much the variation of slat angle, slat colour and slat absorptivity of venetian blind would be affected on the heating and cooling load of building, and also which colour and angle of slat was optimal for the heating and cooling load of building.

• 한국지열·수열에너지학회논문집
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• 제12권4호
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• pp.21-26
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• 2016

In this study, the control strategies of indoor air temperature in floor radiant heating system were researched by computer simulation. The temperature difference based time control method using the difference of indoor set temperature and indoor temperature is compared with the existing On-Off control one for heating control performances. As a result, the temperature difference based time control method shows better thermal environmental characteristics in case of selected operational conditions in comparison with existing control one.