http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
공소정,권재현,홍대영,하민우,이준영 전력전자학회 2022 전력전자학회 논문지 Vol.27 No.3
This paper proposes a test device designed for developing a high-voltage multilayer ceramic capacitor (MLCC). The proposed topology consists of an energy recovery circuit for charging/discharging capacitor, a flyback converter, and a boost converter for supplying power and a bias voltage application to the energy recovery circuit. The energy recovery circuit designed with a half-bridge converter has auxiliary switches operating before the main switches to prevent excessive current from flowing to the main switches. A prototype has been designed to verify the reliability of target capacitors following the voltage fluctuation with a frequency range below 65 kHz. To conduct high root mean square (RMS) current to the capacitor as a load, the MLCC test was conducted after the topology verification was completed through the film capacitor as a load. Through the agreement between the RMS current formula proposed in this paper and the MLCC test results, the possibility of its use was demonstrated for high-voltage MLCC development in the future.
공소정,권재현,홍대영,하민우,이준영,Kong, So-Jeong,Kwon, Jae-Hyun,Hong, Dae-Young,Ha, Min-Woo,Lee, Jun-Young 전력전자학회 2022 전력전자학회지 Vol.27 No.3
This paper proposes a test device designed for developing a high-voltage multilayer ceramic capacitor (MLCC). The proposed topology consists of an energy recovery circuit for charging/discharging capacitor, a flyback converter, and a boost converter for supplying power and a bias voltage application to the energy recovery circuit. The energy recovery circuit designed with a half-bridge converter has auxiliary switches operating before the main switches to prevent excessive current from flowing to the main switches. A prototype has been designed to verify the reliability of target capacitors following the voltage fluctuation with a frequency range below 65 kHz. To conduct high root mean square (RMS) current to the capacitor as a load, the MLCC test was conducted after the topology verification was completed through the film capacitor as a load. Through the agreement between the RMS current formula proposed in this paper and the MLCC test results, the possibility of its use was demonstrated for high-voltage MLCC development in the future.
하민우,공소정,이준영,김민기,석오균 대한전기학회 2023 전기학회논문지 Vol.72 No.11
Multilayer ceramic capacitors (MLCCs) have been used in various electronics including electric vehicles. Dielectric absorption of BaTiO3-based X7R MLCCs is reported in the manuscript. We reviewed the dielectric absorption in detail which was not DC or AC characteristics. We fabricated the X7R MLCCs and measured the devices using an LCR meter, a test fixture, and two source measure units. The dielectric absorption was measured in the fabricated devices. And then the ω0, Cd, and Rd were altered by rms voltage of AC signals. However, these were not affected by the DC voltage. The C∞ from atomic or molecular polarization was not altered by the Vrms and VDC which means this study is right. When the operating frequency of the X7R MLCCs is less than the frequency when the dielectric absorption activates, the capacitance reduces from C∞ + Cd to C∞. We should suppress the dielectric absorption of the MLCCs which generates from an insulating layer. The dielectric absorption can be used to determine the mass production of commercial MLCCs.
김장호,조우영,서승연,남태경,강문주,공소정,정희연,이경석,김완종 순천향대학교 기초과학연구소 2019 순천향자연과학연구 논문집 Vol.25 No.2
We observed the structural difference of tissues between adult and fetus rat with a light microscope. Skin and testis were extracted from fetus and adult rats and were processed to paraffin section. Under microscope, the periderm was observed on the epidermis in fetal skin tissue. It was also confirmed the thickness of adult skin was about 8 times thicker than that of fetus. Hair, gland and other structures that observed in adult tissue were not appeared in fetal skin tissue. In the fetal testis, sperms were not observed and seminiferous tubule was composed of 2-3 layers. On the other hand, seminiferous tubule in adult tissue was composed of 5-6 layers. And well differentiated reproductive cells including sperm and primary spermatocyte were observed in the tubules. In conclusion, adult tissue structure was more complicate and diverse than that of fetus tissue.