• Journal of the Korean Society for Precision Engineering
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• v.30 no.8
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• pp.779-784
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• 2013

Increased efficiency and improved performance associated with light-weight materials were investigated in this study. Numerous studies have investigated surface treatments to improve the fatigue strength of metals. Laser heat treatment is a promising method because the power and spot size can be easily controlled, allowing a small heat affected zone (HAZ). However, changes in the material properties can result; in particular, the material can become more brittle. In this study, a combination of laser heat treatment and vibration peening was proposed to increase fatigue strength without changing the material characteristics. SCM440H was investigated experimentally, and specimens were tested using a giga-cycle ultrasonic fatigue tester. The results show that the combination of these two processes significantly increased the fatigue strength and, furthermore, different fracture types were observed after a small and large number of cycles.

• Journal of applied mathematics & informatics
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• v.7 no.3
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• pp.787-800
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• 2000

In this paper we consider an optimal control system described by n-dimensional heat equation with a thermal source. Thus problem is to find an optimal control which puts the system in a finite time T, into a stationary regime and to minimize a general objective function. Here we assume there is no constraints on control. This problem is reduced to a moment problem. We modify the moment problem into one consisting of the minimization of a positive linear functional over a set of Radon measures and we show that there is an optimal measure corresponding to the optimal control. The above optimal measure approximated by a finite combination of atomic measures. This construction gives rise to a finite dimensional linear programming problem, where its solution can be used to determine the optimal combination of atomic measures. Then by using the solution of the above linear programming problem we find a piecewise-constant optimal control function which is an approximate control for the original optimal control problem. Finally we obtain piecewise-constant optimal control for two examples of heat equations with a thermal source in one-dimensional.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.105-106
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• 2019

In this research, considering the practical conditions at field, thermal cracking method was suggested based on the comparative analysis between predicted value and actual value obtained from the actual structure member with optimum mix design. The optimum mix design was deduced from the various mix designs with various proportions of cementitious binder for upper and lower placement lifts of mat-foundation mass concrete. Therefore, it can be stated that applying low heat mix design and different heating technique between upper and lower placement lifts for mass concrete are efficient to control the thermal cracking. As future issues, based on the interpretation result value, we will select the optimal combination that is applied specifically to the actual site, and deeply analyze the correlation between the measured value and the analysis value through the combination and the test of the actual structure.

• JOURNAL OF ELECTRICAL WORLD
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• no.5 s.25
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• pp.17-19
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• 1972

• Journal of the Korean Solar Energy Society
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• v.35 no.6
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• pp.51-60
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• 2015

In statutes on the promotion of distribution of new and renewable energy, which were revised in 2014, daylight system and fuel cell were added in addition to existing new and renewable energy sources. This study, therefore, aimed at setting up targets for the introduction of daylight system and analyzing the installation rate of new and renewable energy which can be provided by daylight system for the aggressive use of daylight system, thereby deducting the optimal combination ratio with other new and renewable energy sources. The results of the study are as follows. First, when a prism-shaped daylight system was installed to a round indoor gymnasium among domestic indoor gymnasiums, out of a supply obligations allotment rate of 15% of new and renewable energy, the rate of daylight system was basically set at 2.5%. Second, therefore, with daylight system coming first, the lacked supply obligations rate was taken up by solar photovoltaic, solar heat and geothermal heat. In addition, using the KRESS Program, economic, technical, environmental and complexity evaluations for the upper 5% was made, deducting the optimal ratio of the system. The results produced the following optimal combination ratios: solar photovoltaic (83.3%) in economic evaluation, solar heat (8.3%) and geothermal heat (75%) in technical evaluation, solar photovoltaic (83.3%) in environmental evaluation, and solar photovoltaic (83.3%, the same as in economic evaluation) in complexity evaluation.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.7
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• pp.891-898
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• 2011

The present work was conducted to get the best geometric information for the optimum design of the complex heat exchanger. The objective function for optimal design was expressed as a combination of pressure drop and heat transfer rate. The geometric parameters for the variables of louver pitch and height, tube width, etc., were limited to ranges set by manufacturing conditions. The optimum geometric parameters were calculated by using empirical correlations and theory. The sensitivity of the parameters and optimum values are shown and discussed. The weighting factor in the objective function is important in the selection of the louver fin-tube heat exchanger.

• The Journal of Korean Medicine
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• v.17 no.2 s.32
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• pp.100-116
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• 1996

Gastric cancer shows the most high friquency in cancers that occurs in Korea. The western medicine treatment for gastric cancer has radiation and surgery, chemical treatment. While, oriental medicine cures the gastric cancer by herb-drugs, acupunture , moxa and srigma. With just one way of treating gastric cancer can't be effective remedy. Because each medicine has a strength and weakness. Thus, it is effective treatment when two medicine combins and supplement each other. We got the following result about a trend of oriental and westernal combination treatment for gastric cancer through studing records. 1. The western medicine treats gastric cancer patient with surgery first and right after surgery. They need on assembly treatent such as chemical and immune treatment. In oriental medicine, they treats gastric cancer patients with differentiation of symptone and signs and treatment(辨證施治)[for example:incoordination between liver and stomach(肝胃不和), insufficiency of spleen and stomach(脾胃虛弱), stagnation of blood stasis and toxic agent(瘀毒內阻), deficiency of yin by stomach heat(胃熱傷陰), reinforcing both qi and blood(氣血雙虧), stagnation of damp-phlegm(痰濕凝結)] and cure for them by acupuncture and stigma, too. 2. In combination with oriental and western medical treatment principle of gastric cancer by each stage is as follows. First stage and second stage gastric cancer is cured with radical surgery mainly. After operation, the herb of invigoration of the spleen(健脾), coordination of the stomach(和胃), and smoothing the liver and regurating the circulation of qi(疏肝理氣), is used for good gastroenteric condition. The second stage patients can be concidered using in combination with chimical treatment. The third stage gastric cancer is treated with radical surgery or with temporizing surgery. After those surgery, herb-drugs treatment is used jointly. The fourth stage patients who have no extensively metastasis or local contraindication can undergo temporizing and curcuit surgical operation. Herb-drugs and chemical treatments are used together for patients after operating. If he has operating contraindication, he would be treated with herb-drugs and chemical treatment. 3. In case of using in combination with oriental and western medical treatment as follows. As for herb-drugs with chemical treatment, reinforcing both qi and blood(補益氣血), invigorate the spleen and the stomach(健脾和胃), reinforcing liver and kidney(滋補脾腎), clear out the heat and relieve the toxic agent(淸熱解毒), can be used and with radiation treatment, clear out the heat and relieve the toxic agent(淸熱解毒), promoting the production body fluid and moisturizing the vicera(生津潤燥), reinforcing both qi and blood(補益氣血), invigorate the spleen and the stomach (健脾和胃), reinforcing liver and kidney(滋補肝腎) etc, can be used. 4. According to the research of oriental and western medical combination treatment are the 5-year-survival degree with oriental and western medicine combination treatment was for better than that just with oriental or western medical treatment. Especially, it has good effect on the third, fourth stage gastric cancer. That is, the middle and the end of stage gastric cancer. 5. The merits of oriental and western medicine combination treatment are lengthers one's life and diminish the bad effect of chemical treatment and radiation treatment be near completion, prevent from relapsing, maintain the balance in their eveirenment of body and improve immunity.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.336-340
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• 2001

Theoretical efforts were taken to investigate an optimum heat treatment process in martensitic stainlesssteel. The approach is based on the combination of the interpolation and extrapolation method of a standard heat treatment technology with the principle of quenching and tempering temperature difference. The relationship of macroscopic structure and fracture toughness and ductility as well as the Hardness and strength has been focused to induce a simple rule to apply with feasibility. As a result it was found that the grain size influences to the fracture toughness and ductility significantly.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2196-2202
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• 1992

The optimum size combination of heat exchangers in a Joule-Thomson(J-T) circuit for small cryogenic systems has been sought analytically, when the circuit is combined with a two-stage Gifford-McMahon(GM) cooler. Full thermodynamic cycle analysis was carried out to predict the performance of the combined refrigeration system. Relevant convective heat transfer coefficients, the computerized properties of helium, and the refrigeration capacity curve of a typical GM cooler have been used in the analysis. The result showed that, by changing the configuration(heat exchanger area ratio) of the system, the performance of the commonly-used GM/J-T refrigerators could be optimized. For the maximum refrigeration performance, the optimum mass flow rate of the refrigerant and the relative size between the heat exchangers have been obtained, when the cooling load was 0.1W at 3.995K with the total heat exchanger area being given.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.6
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• pp.257-262
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• 2014

This paper describes an experimental study for heating performance that can be used in R-134a automobile heat pump systems. The heat pump system is widely studied for heating system in zero-emission vehicles to attain both the small power consumption and the effective heating of the cabin. This paper presents the experimental results of the influence on heating capacity and coefficient of performance of heat pump system. Tests were performed with different sizes of internal and external heat exchangers, and refrigerant flow rate was also considered in two-way flow devices. In addition, the heat, air, and water sources with the heat pump system were examined. The experimental results with the heat pump system were used to analyze the impact on performances. The best combination of performance was A-inside heat exchanger, B-outside heat exchanger, and B-flow device, respectively. In addition, a water heat-source was found to give roughly 40% of better performance than an air heat-source heat pump system.