• 대한전자공학회논문지
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• 제23권6호
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• pp.773-779
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• 1986

In this paper, we discuss fabrication and characteristics of the Vertical Double diffused MOS(VDMOS) transistor. The epi layers of starting wafers are 18~22\ulcorner in thickness and 8~12\ulcornercm in resistivity. The channel regions are defined through the self-aligned double diffusion process. The characteristics of the fabricated VDMOS are breakdown voltage of 240V, threshold voltage of 2V, on-resistance of 226\ulcornerand transconductance of 3x10**-3 mho.

• Wind and Structures
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• 제17권6호
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• pp.647-670
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• 2013

The paper presents a numerical approach to study of fluid flow characteristics and to predict performance of wind turbines. The numerical model is based on Finite-volume method (FVM) discretization of unsteady Reynolds-averaged Navier-Stokes (URANS) equations. The movement of turbine blades is modeled using moving mesh technique. The turbulence is modeled using commonly used turbulence models: Renormalization Group (RNG) k-${\varepsilon}$ turbulence model and the standard k-${\varepsilon}$ and k-${\omega}$ turbulence models. The model is validated with the experimental data over a large range of tip-speed to wind ratio (TSR) and blade pitch angles. In order to demonstrate the use of numerical method as a tool for designing wind turbines, two dimensional (2-D) and three-dimensional (3-D) simulations are carried out to study the flow through a small scale Darrieus type H-rotor Vertical Axis Wind Turbine (VAWT). The flows predictions are used to determine the performance of the turbine. The turbine consists of 3-symmetrical NACA0022 blades. A number of simulations are performed for a range of approaching angles and wind speeds. This numerical study highlights the concerns with the self-starting capabilities of the present VAWT turbine. However results also indicate that self-starting capabilities of the turbine can be increased when the mounted angle of attack of the blades is increased. The 2-D simulations using the presented model can successfully be used at preliminary stage of turbine design to compare performance of the turbine for different design and operating parameters, whereas 3-D studies are preferred for the final design.

• 보건교육건강증진학회지
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• 제23권1호
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• pp.23-43
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• 2006

Objectives: To investigate the drinking behavior and related factors of community residents in G city. Methods: Examination was executed with questionnaire to 1973 adults. Data were collected from October 1, 2005 to November 16, 2005. Drinking behavior involves rate of drinking, frequency of drinking, age of starting drinking, drinking amount, rate of attempts to drink moderately and reasons for reducing drinking. Related factors involves the general characteristics, the habits of health behaviors. This was analyzed with frequency, percentage, mean, standard deviation, x2-test, t-test, ANOVA and logistic regression. Results: The drinking rate of the respondents was 67.4%, that rate of male was 83.1%, while that rate of female was 52.5%. The drinking rate was higher in groups of younger aged and highly educated people than that rate of the other groups. The highest level of drinking frequency was ones or twice a week. The drinking frequency of those who drank more than three times weekly was higher in the groups of male, old aged, married people, low educated people, rural residents, farmers or fisherman or laborers and those who unemployed or who did not exercise frequently and control their body weight. These individuals also preferred salty food and meat and fish, dined out frequently, did not visit dental clinic regularly, and tend to be smokers. The mean of the age of starting drinking was 21.17 year-old, that of males was 19.94 year-old, that of females was 22.82 year-old. The mean of the age of starting drinking was lower in groups of male, young aged, unmarried, college educated, rural residents, clerks, high monthly income, healthy and no illness, and smokers than that of the other group. The average of the drinking amount was 5.77 pack, that of males was 7.41 pack, and that of females was 3.31 pack. The drinking amount is much more in groups of males, fifties, unmarried, college educated, rural residents, self-employed, healthy people, and smoker than the other. 33.4% of the respondents attempted to drink moderately. According to the reasons of trying to drink moderately, the rate of prevention illness was highest. Conclusions: The variables of influencing drinking were sex, marital status, education, smoking, monthly income, health status, and stress.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.331-334
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• 2011

램제트 엔진의 성능은 초음속 흡입구의 성능과 밀접한 연관이 있다. 초음속 흡입구 내부 유동 특성을 관찰하기 위해 실험적/전산해석적 연구를 수행하였다. 자발 시동이 가능한 2차원 실험 모델을 설계 제작하고 마하 2.5 초음속 풍동을 이용한 실험적 연구와 Menter's SST 난류 모델과 RANS 방정식에 기본한 전산해석 결과로부터 내부 유동 특성을 정리하였다. 흡입구의 안정 작동 조건에서의 의사충격파(Pseudo-shock wave)와 불안정 작동 조건의 버즈 현상에 대해 자세한 가시화 결과를 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.964-966
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• 2003

The three-phase induction motor is rugged, reliable, long-lived, self-starting, smooth-running. But it is relatively inexpensive and three-phase power in not available everywhere, so if possible we need single-phase motor with the same characteristics. In fact, single-phase induction motors have excellent characteristics and outnumber the three-phase variety. Most of the small electric motors used in home, farm, or office are single-phase induction motors of one type or another. This electric motors application field need most energy saving type drive according to enlargement of electronic goods and to tend high class. The paper is proposed a various phase control methods for energy saving of single- phase induction motor. The controllers that are embodied by each method can use by various usage according to each performance and it is considered that application may help in the electrical energy saving because is possible to other electrical appliances.

• 한국실내디자인학회논문집
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• 제14호
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• pp.99-106
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• 1998

Today's consumers have the behavior of purchasing that is self-value-centered and distinctly goal-conscious. Because of this trend the new shops that sell well have the characteristics that effectely transfers strong store-image. The starting point of selling is showing. To appeal to the sense of more consumers and to facilitate the act of consumption you should express more surely store and image of merchandise in the limited space of sales room. Especially in the compound living goods store which sell various items of products the role of presenting the whole merchandises attractive and organized is of utmost importance and the interior planning of show rooms and displaying the room according to the actual sales. According to this the goal of this study is to create not only the convenience of purchasing but also distinguished store image through organizing show rooms according to themes as a part of VMD strategy.

• 한국전기전자재료학회논문지
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• 제19권2호
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• pp.200-206
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• 2006

An electric power efficiency of electrodeless fluorescent lamp depens on a big relative property of gas, gas pressure, lamp formation, ingredients of magnetic substance and shape and action frequency etc. in lamp. We used magnetic substance that opens self-examination material of electrodeless fluorescent lamp antenna. We used Mn-Zn type as the Ferrite. We have examined resistance, impedance and Q-factor's frequency characteristic by ferrite. Coil turns were changed from 13 to 15 turns to recognize brightness change of lamp by winding number. Optical equipment (LS-100) was used to measure brightness. We could know Q-factor's difference according to material is important part of antenna design. When an electrodeless fluorescent lamp was made using T company's PE22, it showed the highest brightness. As number of winding is increased the brightness increased, and starting characteristic became good.

• International Journal of Fluid Machinery and Systems
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• 제5권1호
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• pp.30-37
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• 2012

A two dimensional Darrieus-type turbine has been proposed for the hydropower utilization of extra-low head less than 2m. In a practical use of Darrieus-type hydro-turbine, head and flow rate may be varied temporally and seasonally. Considering that the cost advantage is required for the low head hydro turbine system, the Darrieus turbine should be operated with high efficiency in the wider range of flow rate possibly by using an additional device with simpler mechanism. In the present paper, an adjustment of inlet nozzle section by lowering the inlet nozzle height is proposed to obtain the preferable inlet velocity in low flow rate conditions. Effects of resulting spanwise partial inlet flow are investigated. Finally, an effective modification of inlet nozzle height over flow rate variation is shown.

• 전기학회논문지
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• 제64권9호
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• pp.1380-1384
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• 2015

The DC motor has the strong characteristics in the speed response, the system parameter variations and the external influence and is used as the speed controller with its good starting torque in the distributing industry. However development of the Microprocessor which is for high speed switching program can make better control system. This paper introduce to design of the high-effective DC motor controller that is using Software Bang-Bang Program of Fuzzy algorithm and to verify a PI controller and a Fuzzy controller.

• 한국기계가공학회지
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• 제2권4호
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• pp.88-94
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• 2003

The DC motor has the strong characteristics in the speed response, the system parameter variations and the external influence and is used as the speed controller with its good starting torque in the distributing industry. However development of the Microprocessor which is for high speed switching program can make better control system. This paper introduce to design of the high-effective DC motor controller that is using Software Bang-Bang Program of Fuzzy algorithm and to verity a PI controller and a Fuzzy controller.