• 전기전자학회논문지
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• 제22권4호
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• pp.916-921
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• 2018

본 논문에서는 고전압, 고전류 동작을 위한 전력 MOSFET 소자에 대한 전기적 특성을 시뮬레이션을 통해 분석하였다. 소자의 정적 특성을 향상시키기 위해 기존의 Si대신 4H-SiC를 이용했다. 4H-SiC는 넓은 에너지 밴드 갭에 의한 높은 한계전계를 갖기 때문에 고전압, 고전류 동작에서 Si보다 유리한 특성을 갖는다. 4H-SiC를 사용한 기존 VDMOSFET 구조는 p-base 영역 모서리에 전계가 집중되는 현상으로 인해 항복 전압이 제한된다. 따라서 본 논문에서는 p-base 영역의 모서리에 곡률을 주어 전계의 집중을 완화시켜 항복 전압을 높이고, 정적 특성을 개선한 곡률 VDMOSFET 구조를 제안하였다. TCAD 시뮬레이션을 통해 기존 VDMOSFET과 곡률 VDMOSFET의 정적 특성을 비교, 분석 하였다. 곡률 VDMOSFET은 기존 구조에 비해 온저항의 증가 없이 68.6% 향상 된 항복 전압을 갖는다.

• Transactions on Electrical and Electronic Materials
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• 제1권3호
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• pp.29-33
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• 2000

The crystallographic and high frequency characteristics of $Fe_{73.9}Cu_{1.0}Nb_{3.5}Si_{14.0}B_{7.6}$ soft magnetic alloys were investigated under magnetic field annealing, The crystallization fraction of annealed samples with longitudinal magnetic fields is higher than that of samples without magnetic field. When the transverse magnetic field is applied, the crystallization fraction does not increases but decreases until $500^{circ}C$. It is found that for samples, the saturation induction are all same with 1.3 T. The coercive field of as-cast samples is 1.03 A/cm, but in annealed samples it decrease from 0.56 to 0.1A/cm with increasing annealing temperature from 400 to $550^{circ}C$. The squareness of annealed samples under transverse magnetic field has a small value than that of both without field and with longitudinal field annealing. It is noted that the magnetic field annealing with transverse direction to amorphous $Fe_{73.9}Cu_{1.0}Nb_{3.5}Si_{14.0}B_{7.6}$ profoundly influenced on the Mossbauer spectra in contrast to that with longitudinal direction and without magnetic field.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1472-1475
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• 1996

D-E hysteresis loops have been measured for the 65/35 mole % copolymer of vinylidene fluoride and trifIuoroethyIene over wide temperature range. The results were analyzed and discussed. The remanent polarization and the coercive field at room termperature were estimated to be 75 $mC/m^3$ and 55 MV/m respectively. D-E hysteresis loops were observed even below the glass transiation temperature$-20^{\circ}C$) and the remanent polarization and the coercive field were larger than larger, as the temperature lower. It seems that the remanent polarization and the coercive field depend on the amorphous region as well as crystalline region in this copolymer. And the ferroelectric-to-paraelectric phase transition was observed at $90^{\circ}C$ on heating and $80^{\circ}C$ on cooling. Double hysteresis loops were observed at the temperature($85^{\circ}C$) of paraelectric phase.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권7호
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• pp.525-529
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• 1999

The influence of ambient gases on field emission performance of Mo-field emitter array(FEA) in the frit-sealing step of field emission display(FED) packaging process was investigated. Mo-tip FEA was mounted on the glass substrate having a surrounded frit(Ferro FX11-137) and fired at $415^{\circ}C$ in the ambient gases of air, $N_2$ and Ar. The Ar gas was proved to be most proper ambient among the used gases through evaluating the turn-on voltage and field emission current of the fired Mo-tip FEA devices. It was confirmed that the Mo surface fired in Ar ambient was less oxidized when compared with another ones annealed in air and Ar ambient by the AFM, XPS, AES and SIMS analysis. Finally, the 3.5 inch-sized Mo-tip FED, which was packaged using frit-sealing process in the Ar ambient, was proposed.

• International Journal of Industrial Entomology and Biomaterials
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• 제15권1호
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• pp.69-73
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• 2007

To establish the indoor-rearing system of the emma field cricket, Teleogryllus emma, the effects of temperature on development and reproduction of the emma cricket have been studied. The influence of temperature on developmental periods of emma field cricket was investigated under the eight temperatures of 15, 18, 21, 25, 27, 29, 31 and $35^{\circ}C$, under $60{\pm}5%$ R.H. and 16L:8D photoperiod. The developmental periods of T. emma nymphs had a range of 124.8 days to 44.4 days at the temperature of $21^{\circ}C$ and $35^{\circ}C$, respectively. At $15^{\circ}C$ and $18^{\circ}C$, however, all tested individuals died before emergence. The highest survival rate was 90% at $25^{\circ}C$, but there were no statistically significant differences among the temperatures. The adult weight increased with increasing temperatures although the weight at $35^{\circ}C$ was decreased. In addition, the influence of temperature on reproduction of emma field cricket was investigated under three temperatures $22^{\circ}C,\;25^{\circ}C\;and\;28^{\circ}C$, under $60{\pm}5%$ R.H. and 16L:8D photoperiod. The longevity of female/male adults were 65.8/79.2 days, 68.5/67.8 days, 46.8/57.4 days at the temperature $22^{\circ}C,\;25^{\circ}C\;and\;28^{\circ}C$, respectively. The preoviposition periods were 32.5 days at $22^{\circ}C,\;22.9^{\circ}C$ days at $25^{\circ}C$ and 22.1 days at $28^{\circ}C$. The highest average fecundity per female was 737.3 at $25^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.341-342
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• 2008

The dynamics of nano particles in LC medium under an external electric field is of theoretical and technological interest. In this work, the dynamical characteristics of fullerene $(C_{60})$ particles in liquid crystal (LC) medium under dc electric field have been investigated. This effect was studied for homogeneously aligned nematic LC cells driven by in-plane field. The $C_{60}$ was found to be aggregated in a form of cluster inside the LC medium. Hence polystytene was used to protect the aggregation of $C_{60}$ in LC medium. When the electric field was applied, the fullerenes start to move in direction of applied electric field. The density of $C_{60}$'s particles at the electrodes increase with increase in the value of applied electric field. The dynamical motions of fullerene $(C_{60})$ particles in liquid crystal (LC) suggest that fullerene can be designed for electrophoretic displays (i.e., electronic ink).

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.61-68
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• 2006

Cemented Sand and Gravel(CSG) is a material made by simple mixing of rock-based raw materials such as excavated soil and riverbed gravel together with cement and water. The use of CSG methodl for cofferdam and large dam is gradually increasing in Japan because a quarry and aggregate plants can be diminished. Also, the CSG method can reduce dam construction cost, construction duration and destruction of environment. In this paper, field test and test construction of CSG method was conducted on Hwabuk Dam. The mechanical properties of CSG, such as compressive strength, extention strength and field permeability test were investigated. From the results of the experimental study, application study of CSG method was discussed.

• Journal of Life Science
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• 제10권2호
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• pp.50-54
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• 2000

The RAD4 gene of Saccharomyces cerevisiae is essential for the incision step of UV-induced excision repair. A yeast RAD4 gene has been previously isolated by functional complementation. In order to identify the RAD4 homologous gene from fungus Coprinus cinereus, we have constructed cosmid libraries from electrophoretically separated chromosomes of the C. cinereus. The 13 C. cinereus chromosomes were resolved by pulse-field gel electrophoresis, hybridized with S. cerevisiae RAD4 DNA, and then isolated homologous C. cinereus chromosome. Here, we report the cloning and characterization of fungus C. cinereus homolog of yeast RAD4 gene. Southern blot analysis confirmed that C. cinereus contains the sequence homologous DNA to RAD4 gene and this gene exists as a single copy in C. cinereus genome. When total RNA isolated from C. cinereus cells was hybridized with the 3.4 kb BglII DNA fragment of the S. cerevisiae RAD4 gene, a 2.5 kb of transcript was detected. The isolated gene encodes a protein of 810 amino acids.

• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.278-282
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• 2004

The Hydrogenated amorphous carbon(a-C:H) thin films are deposited on silicon with a close field unbalanced magnetron(CFUBM) sputtering systems. The experimental data are obtained on the depositon rate and physical properties of a-C:H films using DC bias voltage and Ar/C$_2$H$_2$ pressure. The depostion rate and the surface roughness decrease with DC bias voltage, but the hardness of the thin films increases with DC bias voltage. And the position of G-peak moves to lower wavenumber indicating an increase in diamond-like carbon characteristics with the lower Ar/C$_2$H$_2$ pressure.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권10호
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• pp.471-476
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• 2005

We proposed an optical modulator of reflective type to compose the electric field sensor, and theoretically analyzed the performance and characteristics. For the high sensitivity of the sensor, a method to improve the modulation index of the modulator was presented. The electric field sensor using Ti:LiNbO$_{3}$ waveguide was fabricated and qualitatively investigated the characteristics by measuring the low frequency electric field. Even though the sensor showed relatively low modulation index, the electric filed strength of 10$^{-2}$V/m was measured. The experimental results revealed the utilities of this type electric field sensor.