• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.40-42
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• 1999

High-speed brushless permanent magnet machines are good for compressor and aerospace applications, etc, since they are conductive to high efficiency, high power density, small size and low weight. This paper describes a diametrically magnetized PM motor with the rating of 4.3kW and 50000 rpm fur high-speed drive applications. To bear strong stress from high speed, rotor was designed cylindrical structure, was magnetized diametrically permanent magnet. The performance characteristic of motor was evaluated by means of FEA(Finite Element Analysis), no-load test And then, in order to find back-EMF constant, used FEA, search coil.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.295-300
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• 2001

A variety of high voltage DC power supplies employing the high frequency inverter are difficult to achieve soft switching considering a quick response and no overshoot response under the wide load variation ranges which are used in medical-use x-ray high voltage generator from 20kV to 150kV in the output voltage and from 0.5mA to 1250mA, respectively. The authors develops soft switching high voltage DC power supply designed for x-ray power generator applications, which uses series resonant inverter circuit topology with a multistage voltage multiplier instead of a conventional high voltage diode rectifier connected to the second-side of a high-voltage transformer with a large turn ratio. A constant on-time dual mode frequency control scheme operating under a principle of zero-current soft switching commutation is described. Introducing the multistage voltage multiplier, the secondary transformer turn-numbers and stray capacitance of high-voltage transformer is effective to be greatly reduced. It is proved that the proposed high-voltage converter topology with dual mode frequency modulation mode control scheme is able to be the transient response and steady-state performance in high-voltage x-ray tube load. The effectiveness of this high voltage converter is evaluated and discussed on the basis of simulation analysis and observed data in experiment.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.388-388
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• 2012

In this letter, We have investigated cell characteristics of the alloy FePt-NDs charge trapping memory capacitors with high-k $Al_2O_3$ dielectrics as a blocking oxide. The capacitance versus voltage (C-V) curves obtained from a representative MOS capacitor embedded with FePt-NDs synthesized by the post deposition annealing (PDA) treatment process exhibit the window of flat-band voltage shift, which indicates the presence of charge storages in the FePt-NDs. It is shown that NDs memory with high-k $Al_2O_3$ as a blocking oxide has performance in large memory window and low leakage current when the diameter of ND is below 2 nm. Moreover, high-k $Al_2O_3$ as a blocking oxide increases the electric field across the tunnel oxide, while reducing the electric field across the blocking layer. From this result, this device can achieve lower P/E voltage and lower leakage current. As a result, a FePt-NDs device with high-k $Al_2O_3$ as a blocking oxide obtained a~7V reduction in the programming voltages with 7.8 V memory.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.374-376
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• 2018

본 연구에서는 라즈베리파이에 부착된 카메라로 사람을 얼굴을 인식하는 영상처리기법을 활용하여 가정용 로봇을 제작하였다. 라즈베리파이에 부착된 카메라를 통해 실시간으로 영상을 입력받아서 사람의 얼굴을 인식하게 한 후 결과에 따라 스마트냉온풍기의 동작을 구분한다. 이는 로봇이 사람이 없는 곳에 냉온풍기를 동작하지 않고, 사람이 있는 곳에만 냉온풍 동작을 하게 함으로써 에너지 활용 효율을 높일 수 있을 것으로 기대된다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.380-382
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• 2018

본 연구에서는 차량에 화물을 손쉽게 싣을 수 있는 휴대용 간이 리프트의 안정성을 위하여 안드로이드 어플리케이션을 활용하여 휴대용 간이 리프트의 소프트웨어를 개발하였다. 이를 위해 Arduino Uno R3 보드를 활용하였다. 기존의 휴대용 간이 리프트를 해체하여 Arduino Uno R3 보드와 회로를 장착하고 블루투스 통신으로 신호를 송수신할 수 있게 하였다. 본 연구를 통하여 물류 활동의 안전작업에 큰 도움을 줄 것으로 예상할 수 있다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.371-373
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• 2018

자전거 등하교 및 출퇴근족의 안전을 위하여 방향 표시등의 기능은 반드시 필요하다. 본 연구에서는 아두이노를 활용하여 조립식 자전거에 방향 표시등 기능을 개발하였다. 아두이노의 간단한 기능을 통해 핸들에 스위치를 부착하여 방향 표시등을 켜고 끄게 할 수 있다. 또한 간단한 기능이므로 자전거를 가지고 있는 사람들이 스스로 DIY를 하여 제작할 수 있는 메이커 활동으로 적합하다고 판단된다. 본 논문에서 제안된 기능을 통하여 자전거에 필요한 서비스를 많이 부착할 수 있는 가능성을 열어두었다.

• Nutritional Sciences
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• 제7권1호
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• pp.8-16
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• 2004

The purpose of this study was to investigate the gene profiles that were up- or down-regulated in the livers of high-fat diet-induced obese mice and $db_-/db_-$ mice with deficient leptin receptor. C57/BL6 normal mice and $db_-/db_-$ mice, respectively, were divided into two groups and fed a standard or high-fat diet for four weeks. Liver weight was unchanged in the normal mice but the high-fat diet led to a 10% weight increase in the $db_-/db_-$mice. Adipose tissue mass increased by about 88% in the normal mice that were fed a high-fat diet and by about 17% in the $db_-/db_-$mice on the high-fat diet. In terms of serum lipids, total cholesterol significantly increased in mice on the high-fat diet. Microarray analysis was carried out using total RNA isolated from the livers of standard or high-fat diet-fed mice of the normal and $db_-/db_-$ strains. The change of gene expression was confirmed by RT-PCR. About 1.6% and 6.8% of total genes, respectively, showed different expression patterns in the normal mice fed the high-fat diet and $db_-/db_-$ mice. As a result of microarray, many genes involved in metabolism and signal pathways were shown to have different expression patterns. Expression of Mgst3 gene increased in the livers of normal and $db_-/db_-$ mice that were fed a high-fat diet. Wnt7b and Ptk9l were down-regulated in the livers of the normal mice and $db_-/db_-$ mice that were fed a high-fat diet. In conclusion, a high-fat diet induced obesity and affected gene expression involved in metabolism and signal pathway.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권4호
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• pp.180-184
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• 2001

The high operation frequency mainly reduces transformer volume in the power supply. A high frequency and high voltage pulse transformer is designed, fabricated, and tested. Switching frequency of the transformer is 100 kHz. Input and output voltages of the transformer are 250 V and 4 kV, respectively. Normal operation power of the transformer is 3 kW. Maximum volume of the transformer is 400 $cm^3$. The power density is thus 7.5 W/$cm^3$. The transformer will be installed in a metal box that has nominal operation temperature of 85 degree centigrade. The transformer and other high voltage components in the box will be molded with Silicon RTV(Room Temperature Vulcaniza) that has a very low thermal conductivity. Procedure of design and test results are discussed. Analytical as well as experimental results of varous paramters such as transformer loss, leakage inductance, distributed capacitance are also discussed. In addition, thermal analysis results from ANSYS code for three different operation conditions are discussed.

• 한국학교보건학회지
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• 제29권3호
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• pp.132-139
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• 2016

Purpose: In this study, we analyzed the correlation between high-caffeine energy drink intake and mental health in high school students. Methods: Analyses were conducted using the data of 27,097 responses from the 2015 Korea Youth Risk Behavior Web-based Survey of general high school students. Data were analyzed by logistic regression based on a complex sample design. Results: High-caffeine energy drink intake was positively correlated with the rates of smoking, alcohol consumption, violence, depression, and suicidal thoughts and negatively correlated with the sense of happiness. Conclusion: High-caffeine energy drink intake has a significant impact on the mental health of high school students. Therefore, in-depth research and policies on high-caffeine energy drink intake and the mental health of young individuals are required.

• Journal of Power Electronics
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• 제7권2호
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• pp.118-123
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• 2007

This paper presents a new ZCS-PWM high frequency inverter. Zero current switching operation is achieved in the whole load range by using a simple auxiliary reverse blocking switch in parallel with series resonant capacitor. Dual duty cycle control scheme is used to provide a wide range of high frequency AC output power regulation that is important in many high frequency inverter applications. It found that a complete soft switching operation can be achieved even for low power setting ranges by introducing high-frequency dual duty cycle control scheme. The proposed high frequency inverter is more suitable for consumer induction heating(IH) applications. The operation and control principle of the proposed high frequency inverter are described and verified through simulated results.