• 전자공학회논문지
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• 제50권7호
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• pp.109-114
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• 2013

전력 MOSFET(산화물-반도체 전위 효과 트랜지스터)는 BLDC 모터와 전력 모듈 등에 광범위하게 사용하고 있다. 기존 전력 MOSFET 구조는 온-저항과 항복전압사이에 절충(tradeoff)이 필요하다. 이러한 절충을 하지 않고 최적화를 하기위해 비균일 초접합 트랜치 MOSFET 를 설계하는데 동일한 항복전압에서 균일 초접합 트랜치 MOSFET보다 낮은 온-저항을 갖도록한다. 이를 위해 드리프트 영역에서 우수한 전기장 분포를 달성하기 위하여 선형구조의 도핑 프로파일을 제안하고, 단위 셀 설계, 도핑농도의 특성분석, 전위분포를 SILVACO TCAD 2D인 Atlas 소자 소프트웨어를 사용하여 시뮬에이션을 수행하였다. 결과로 100V 급 MOSFET에서 비균일 초접합 트랜치 MOSFET가 균일 초접합 트랜치 MOSFET보다 온-저항에서 우수한 특성을 보여주고 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권1호
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• pp.7-11
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• 2007

The study was conducted on 162 adult male Haemonchus contortus of sheep collected from Avikanagar, Jaipur and Bikaner regions to diagnose the benzimidazole (BZ) resistance in H. contortus. The BZ resistance is primarily linked with the mutation in ${\beta}$-tubulin isotype 1 gene which substitute phenylalanine (Phe) into tyrosine (Tyr) at the 200 codon of the gene. An allele specific polymerase chain reaction (AS-PCR) technique was used for diagnosis of BZ resistance in H. contortus. In AS-PCR, one reverse primer (TGG 312) was used in two separate reactions with each of 2 forward primers (resistant TGG 331 and susceptible CAW 106 primer) that differed only at 3' nucleotide position. Therefore, the amplified products from resistant and susceptible parasites were produced 267 and 266 bp, respectively. A total of 162 parasites were genotyped, of which 130 parasites found homozygous resistant 'rr', 22 heterozygous 'rS' and 10 homozygous susceptible 'SS' type. The prevalence of 'rr' individuals was higher in Jaipur (98%) followed by Avikanagar (93%) and Bikaner (50%) regions. Overall, the prevalence of BZ resistant allele (r) was higher (87%) as compared to 13% of BZ susceptible allele (S).

• 한국세라믹학회지
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• 제35권10호
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• pp.1070-1077
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• 1998

Effect of current collecting layer on the cathode was characterized by AC impedance spectroscopy at 800$^{\circ}C$ under flowing air. LSM-YSZ composite cathode showed lower polarization resistance due to the in-crease of triple phase (LSM/YSZ/Pore) boundary length by incorporation of YSZ. Ohmic resistance {{{{ {R }_{1 } }} of LSM-YSZ was higher than that of pure LSM however because in-plane resistance of the cathode was fair-ly high due to its high specific resistivity. To reduce the in-plane resistance of LSM-YSZ cathode cathode side current collecting layer was required. Ohmic resistance {{{{ {R }_{1 } }} was reduced after forming LSM current col-lecting layer on the LSM-YSZ cathode. In case of pure LSM cathode the formation of Pt, or LSCO current collecting layer reduced polarization resistance {{{{ {R }_{p } }} but ohmic resistance {{{{ {R }_{1 } }} was relatively constant. After annealing of LSM cathode with Pt current collector at higher temperature polarization resistance {{{{ {R }_{p } }} was in-creased but ohmic resistance {{{{ {R }_{1 } }} was constant. These phenomena indicate that Pt or LSCo current col-lecting layers act as a catalytic layer for oxygen reduction of pure LSM cathode. LSCO current collector was effective in reducing the ohmic and polarization resistance of LSM-YSZ cathode.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1551-1554
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• 2005

The Titanium has many superior characteristics Which are specific strength, heat resistance, corrosion resistance, organism compatibility, non-magnetic and etc. and their quantity are abundant. this study performed turning operation of Ti-6Al-4V alloy using the TiAlN Coate Tool which treated PVD (Physical Vapor Deposition). Experimental works are also executed to measure cutting force, chip figuration and surface roughness for different cutting conditions. As a result of study. Tool wear was serious at over 100m/min of cutting speed and cutting condition was excellent at 1.0mm of cutting depth.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.65-66
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• 2019

In this study, flexural strength and impact resistance were evaluated to investigate the fiber length effect of amorphous metallic fiber. As a result, in the case of 30AFRCC, cutoff behavior due to excellent bonding performance by large specific surface area has greatly influence on the flexural and impact resistance performance. In the case of 15AFRCC, the bonding efficiency is relatively low, because the specific surface area is smaller than that of 30AFRCC and the number of fiber is large, so the effect of improving the flexural and impact resistance performance is smaller than that of 30AFRCC.

• Corrosion Science and Technology
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• 제6권1호
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• pp.1-6
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• 2007

Ferritic stainless steels for the SOFC interconnect applications are required to possess not only a good oxidation resistance, but also a high electrical conductivity of the oxide scale that forms during exposure at the SOFC operating environment. In order to understand the effects of alloying elements on the oxidation behavior of ferritic stainless steels and on the electrical properties of oxide scales, two kinds of commercial ferritic stainless steels, STS 430 and STS 444, were investigated by performing isothermal oxidations at $800^{\circ}C$ in a wet air containing 3% $H_{2}O$. The results showed that STS 444 was superior to STS 430 in both of the oxidation resistance and the area specific resistance. Although STS 444 contained a less amount of Mn for the $(Mn,Cr)_{3}O_{4}$ spinel formation than STS 430, the minor alloying elements of Al and Mo in STS 444, which were accumulated in the base metal region adjacent the scale, were suggested to reduce the scale growth rate and to enhance the scale adherence to the base metal.

• Architectural research
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• 제13권1호
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• pp.25-32
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• 2011

The purpose of this research is to investigate the effect of specific hydration reaction on the stiffening process of cement paste. The cement compositions are manipulated to cause specific hydration reactions (secondary gypsum and syngenite formation) responsible for false set, and the relationship between specific hydration reactions and the flow and stiffening behavior of cement paste were investigated using modified ASTM C 403 penetration resistance measurement and oscillatory shear rheology. X-ray powder diffraction (XRD) was used for the phase identification associated with premature stiffening of cement paste. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) were used for verification of syngenite formation. From the results, both secondary gypsum and syngenite formation caused faster stiffening and set. The amount of syngenite produced during 1 hour hydration was approximately 1 % of total mass of the cement paste, but cement paste with syngenite formation showed significantly accelerated stiffening behavior compared to normal cement paste.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.308-313
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• 2002

In end milling process, the undeformed chip section area and cutting forces vary periodically with phase change of the tool. However, the real undeformed chip section area deviates from the geometrically ideal one owing to cutter runout and tool shape error. In this study, a method of estimating the real undeformed chip section area which reflects cutter runout and tool shape error was presented during down end-milling of Inconel 715 using measure cutting forces. Contrary to the up-end milling the value of radial specific cutting resistance, $K_r$, becomes larger as the helix angle increases from $30^{\circ}$ to $40^{\circ}$ and it shows almost same value at $50^{\circ}$ The value of tangential specific cutting resistance, $K_t$ becomes larger as the helix angle increases same as in up-end milling, the $KK_r$, and $K_t$ values show a tendency to decrease with increase of the modified chip section area and this tendency is distinct with helix angle $40^{\circ}$.

• 한국전기전자재료학회논문지
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• 제20권5호
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• pp.430-435
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• 2007

This paper describes the results of electrical characteristics assessment for organic insulations of polyethylene(PE) series insulations and acrylonitrile butadiene styrene copolymer(ABS). In the experiment, 4 kinds of specimens by composition density were tested in relative permittivity, specific resistance and tracking duration. A WinDETA system and a tracking test set manufactured for this assessment were used to measure the dielectric parameters and tracking duration, respectively. In measuring the tracking duration, the time from testing voltage application to testing circuit breaking due to the tracking current was measured. As a result, dielectric dispersion was observed in measuring the relative permittivity of ABS. It was confirmed that the relative permittivity decreased with the density of the PE series insulations and it depends rather on the temperature than frequency. In most specimens, specific resistance exponentially decreased with frequency and the result for each specimen was almost similar. By the way, in the tracking test, all the PE series insulations showed more excellent performance than ABS and especially in the case of HDPE, its tracking withstand performance was the best.

• 한국작물학회지
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• 제40권2호
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• pp.125-132
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• 1995

유형이 다른 품종들간에 기공밀도와 기체확산저항의 차이와 광합성 속도에 미치는 영향 등을 비교 검토한 바 일반적으로 Indica 품종의 기공밀도가 Japonica 품종보다 컸으나 기체확산은 작았다. Indica 품종과 Japonica 품종간의 교잡을 통하여 육성한 품종들의 기공밀도와 기체확산 저항은 중간가를 나타냈다. 기공밀도와 기체확산저항 광합성 속도 간에는 현저한 정의 상관을 보였지만 특수엽중과는 현저한 질의 상관을 보였고, 단엽면적과의 상관관계는 현저하지 않았다. Indica 품종과 Japonica품종간의 교잡을 통하여 Indica 품종의 기공밀도가 크고 기체확산저항이 낮은 특성과 Japonica 품종의 특수 엽중이 큰 특성을 결합할 수 있다면 광합성 속도를 더욱 높일 수 있으리라 추측된다.