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자유형 단조 공정에 의한 Ti-6Al-4V 빌렛 제조기술 (Manufacturing Process of the Ti-6Al-4V Billet by the Open-die Forging)

  • 김국주;최승식;황창률;김종식;염종택;이종수
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2006년도 춘계학술대회 논문집
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    • pp.377-380
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    • 2006
  • Manufacturing process of Ti-6Al-4V alloy billet was investigated with FEM simulation and experimental analysis. Before the breakdown process of Ti-6Al-4V alloy ingot, FEM simulation for the breakdown processes of Ti-6Al-4V alloy ingot was used to calculate the forging load and state variables such as strain, strain rate and temperature. In order to breakdown the ingot structure and make an equiaxed structure billet, two different processes were employed for a VAR/VAR processed Ti-6Al-4V alloy ingot. Firstly, the ingot was cogged in single-phase $\beta$ field at the temperature of $1,100^{\circ}C$. In the process, the coarse and inhomogeneous structure developed by the double melting process was broken down. The second breakdown was performed by upsetting and cogging processes in $\alpha+\beta$ phase field to obtain the microstructure of fine equixed $\alpha$ structure in the matrix of transformed $\beta$. Finally, the mechanical properties of Ti-6Al-4V alloy billet made in this work were compared with those of other billet and ring product.

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유기산을 이용한 생굴의 Vibrio vulnificus 억제 (Inhibition of Vibrio vulnificus in Oysters using Organic Acids)

  • 김창렬;이재일;신은하;이용규
    • 한국식품영양학회지
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    • 제10권3호
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    • pp.320-324
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    • 1997
  • 유기산 처리법을 이용하여 15$^{\circ}C$ 저장 동안 생굴의 V. vulnificus strain 29307의 세균수 변화에 대한 영향을 조사하였다. 각각 3분 동안 0.5% 초산, 0.5% 유산, 또는 0.5% 구연산을 침지한 생굴은 저장 4일 후부터 V. vulnificus가 검출되지 않았다. 2% 초산 함유한 3% 알지닉산 처리구는 저장 2일 후부터 V. vulnificus가 검출되지 않았으며, 수돗물로 처리한 대조구는 저장 4일 동안 V. vulnificus가 분리되었다. 본 연구의 결과를 토대로 알지닉산과 초산의 조합은 각 유기산 처리구보다 V. vulnificus에 대한 항균력을 증진하였다.

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플래시와 자바를 이용한 765kV 변전설비의 웹 기반 교육용 OJT 개발 (Development of Web-based Educational OJT on 765kV Substation Facilities using Flash and Java.)

  • 안상민;안상필;김동수;김철환;신한철;윤귀한;장성익
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 하계학술대회 논문집 A
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    • pp.431-433
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    • 2001
  • 현재 우리 나라는 대용량 전력공급의 필요에 의해 765kV 초고압 송전망과 변전설비를 증설하고 있다. 앞으로 765kV 변전소는 우리 나라 전력계통의 중추적 역할을 담당하게 될 것이다. 하지만, 아직까지도 이에 대한 교육은 미진한 상태이다. 따라서 이러한 765kV 변전설비에 대한 전반적인 내용을 교육하기 위하여, 플래시와 자바를 이용한 교육용 OJT 문서를 인터넷상에서 상세하고 보다 편리하게 학습할 수 있도록 개발 하고자 한다. 웹 기반의 765kV 변전설비에 대한 교육용 OJT는 학습자가 능동적으로 대처할 수 있도록 구성되어 진다. 또한 앞으로 점차 증가하게 될 765kV 변전소에 관한 내용을 다루어 봄으로써, 765kV 변전설비에 대한 개괄적인 내용도 알 수 있고, 앞으로의 변전설비 추이에 관한 내용을 짐작할 수 있도록 한다.

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Hot Wall Epitaxy(HWE) 방법에 의해 성장된 $CuInS_2$ (Growth and Characterization of $CuInS_2$ Single Crystal Thin Film by Hot Wall Epitaxy)

  • 최승평;홍광준
    • 한국결정학회지
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    • 제11권3호
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    • pp.137-146
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    • 2000
  • The stoichiometric mix of evaporating materials for he CuInS₂ single crystal thin films was prepared. To obtain the single crystal thin films, CuINS₂ mixed crystal was deposited on etched semi-insulator GaAs(100) substrate by the hot wall epitaxy(HWE) system. The source and substrate temperature were 640℃ and 430℃, respectively and the thickness of the single crystal thin films was 2 ㎛. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility deduced from Hall data are 9.64x10/sup 22//㎥ and 2.95x10/sup -2/ ㎡/V·s, respectively at 293 K. he optical energy gap was found to be 1.53 eV at room temperature. From the photocurrent spectrum obtained by illuminating perpendicular light on the c-axis of the thin film, we have found that the values of spin orbit coupling splitting ΔSo and the crystal field splitting ΔCr were 0.0211 eV and 0.0045 eV at 10K, respectively. From PL peaks measured at 10K, were can assign the 807.7 nm (1.5350 eV) peak to E/sub x/ peak of the free exciton emission, the 810.3 nm(1.5301 eV) peak to I₂ peak of donar-bound exciton emission and the 815.6 nm(1.5201 eV) peak to I₁ peak of acceptor-bound excition emission. In addition, the peak observed at 862.0 nm(1.4383 eV) was analyzed to be PL peak due to donor-acceptor pair(DAP).

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CdS단결정의 열랄격전류에 관한 연구 (A Study on the Thermally Stimulated Current in CdS Single Crystal)

  • 유용택
    • 한국통신학회논문지
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    • 제7권2호
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    • pp.59-65
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    • 1982
  • 本實驗에 파이퍼-폴리시(piper-polish)法으로 만든 單結晶에 Sb와 In을 이온衝激시킨 스포트에 대하여 熱剌激電流를 測定하였다. Sb와 In을 각각 衝激시켜 熱剌激電流를 測定한 결과 중첩된 피이크가 觀察되었는데 이를 서멀 클리닝(thermal cleaning)法으로 分離하여 147K에서 0.25eV와 0.31eV의 活性에너지를 얻었다. 스포트를 冷却시키면서 光勵起시키면 0.25eV의 트랩(trap)이 사라지고 0.85eV의 트랩이 새로 나타났다. 光電導가 양호한 結晶에서 T.S.C.가 잘 測定되었다.

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Characterization of Ethanol Fermentation Using Alginate Immobilized Thermotolerant Yeast Cells

  • Sohn, Ho-Yong;Park, Wan;Jin, Ingnyol;Seu, Jung-Hwn
    • Journal of Microbiology and Biotechnology
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    • 제7권1호
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    • pp.62-67
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    • 1997
  • To enhance the hyperproductive and low energy-consuming ethanol fermentation rate, the thermotolerant yeast S. cerevisiae RA-74-2 cells were immobilized. An efficient immobilization condition was proved to be $1.5{\%}$ (w/v) alginate solution, neutral pH and 20 h activation of beads. The fermentation characteristics and stability at various temperatures were examined as compared with free S. cerevisiae RA-74-2 cells. The immobilized cells had excellent fermentation rate at the range of pH 3-7 at 30-$42^{\circ}C$ in 15-$20{\%}$ glucose media. When the seed volume was adjusted to 0.12 (v/v) (6ml bead/50 ml medium), $11{\%}$ (w/v) ethanol was produced during the first 34 hand $12.15{\%}$ (w/v) ethanol [$95{\%}$ (w/v) of theoretical yield] during the first 60 h in $25{\%}$ glucose medium. In repetitive fermentation using a 2 litre fermentor, 5.79-$7.27{\%}$ (w/v) ethanol [76-$95{\%}$ (w/v) of theoretical yield] was produced during the 40-55 h in $15{\%}$ glucose media. These data suggested the fact that alginate beads of thermotolerant S. cerevisiae RA-74-2 cells would contribute to economic and hyperproductive ethanol fermentation at high temperature.

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다 출력 LLC 직렬 공진 컨버터 (Multi-Output LLC Series Resonant Converter)

  • 강성인;김주훈;김은수;박준호;이현관;허동영
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2008년도 추계학술대회 논문집
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    • pp.29-32
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    • 2008
  • 최근 PDP Display 시장은 해를 거듭 할수록 가격 경쟁이 치열해 지고 있다. 그에 따라 PSU(Power Supply Unit) 모듈의 저 가격화 및 경량화가 요구되고 있고, 요구조건을 만족하기 위해 여러 출력을 하나로 통합화 하는 다 출력 구조의 변압기가 적용되고 있다. 본 논문에서는 서스테인 전원부($V_s$)와 어드레스 전원부($V_a$), 그리고 Multi 18V전원부($V_m$)를 하나의 변압기에 일체화 하였다. 그리고 어드레스 전원부($V_a$)와 Multi 18V전원부($V_m$)의 부하 추가에 따라 서스테인 전원부($V_s$)의 전압 이득 특성 및 공진특성 변화를 확인하였다. 또한 다 출력 LLC 직렬공진 컨버터 설계 시 고려사항과 동작 특성으로 42인치 HD PDP 전원에 적용하여 검증한 결과에 대하여 서술 하였다.

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Complete sequence of genome RNA of Pepper mottle virus Korean isolate

  • H.I. Yoon;J, Y. Yoon;Park, G.S.;Park, J.K.;K.H. Ryu
    • 한국식물병리학회:학술대회논문집
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    • 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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    • pp.147.2-148
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    • 2003
  • Complete nucleotide sequence of genome RNA of a Korean isolate of Pepper mottle virus (PepMoV-Vb) from field-collected diseased paprika (Capsicum annuum var grossum) was determined in this study. Symptoms of isolates of PepMoV were divided largely into two groups, vein banding (Vb) and vein clearing (Vc) patterns. PepMoV-Vb RNA consists of 9,640 nucleotides excluding the poly(A) tail. A single open reading frame was identified beginning at nucleotide position 169 encoding a polyprotein of 3024 amino acids which is typical of the Potyvirus genus. The complete nucleotide sequence and coding regions of PepMoV-Vb were compared to that of 11 potyviruses within the genus Potyvirus. The overall nucleotide sequence identity was 94.7 and 94.1% identical to PepMoV-C and PepMoV-FL, respectively. Full-length cDNAs of PepMoV-Vbl were synthesized from purified viral RNAs by RT-PCR and their genome structure was analysed by RFLP analysis. This is the first report on complete nucleotide sequence of PepMoV isolated from paprika in Korea.

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Studies on the Comparative Performance of Victory-1, S-36 and Kanva-2 Mulberry Genotypes and their Impact on Silkworm Rearing under Telangana Conditions of Andhra Pradesh.

  • Venkataramana, P.;Suryanarayana, N.;Kumar, Vineet;Sarkar, A.
    • International Journal of Industrial Entomology and Biomaterials
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    • 제5권2호
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    • pp.175-182
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    • 2002
  • A new high yielding mulberry genotype, Victory-1 (V-1) was recommended to the field for irrigated areas by Central Sericultural Research and Training Institute (CSRTI), Mysore during 1996-1997. As K-2 and S-36 mulberry genotypes are already in the field, a study on the comparative performance of V-1, 5-36 and K-2 varieties, in terms of leaf yield, yield attributes, leaf moisture and moisture retaining capacity and their impact on silkworm rearing was carried out under Telangana conditions of Andhra Pradesh during 1999-2001. Among the three genotypes the leaf yield was found to be significantly (P < 0.01) higher in V-1 (64,130 kg/ha/yr) followed by S-36 (44,064 kg/ha/yr) and K-2 (23,990 kg/ha/yr). The maximum leaf moisture was also observed in V-1 (71.84%) compared to S-36 (66.86%) and K-2 (64%). The moisture retaining ability was more in V-1 (70.17%) followed by S-36 (66.20%) and K-2 (60.08%). The yield attributes were found to be significantly (P < 0.01) enhanced in V-1 over S-36 and K-2. Silkworm rearing results (bioassay) indicated a significant (P < 0.01) reduction in larval duration and improvement in larval weight, effective rate of rearing by number and weight, single cocoon and shell weights and shell ratio in the silkworm lots fed on V-1 variety followed by S-36 and K-2. Hence, in this study, V-1 was found to be superior among the three varieties studied.

MIPI D-PHY를 위한 2-Gb/s SLVS 송신단 (A 2-Gb/s SLVS Transmitter for MIPI D-PHY)

  • 백승욱;정동길;박상민;황유정;장영찬
    • 한국산업정보학회논문지
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    • 제18권5호
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    • pp.25-32
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    • 2013
  • 고속 저전력 모바일 응용분야를 위한 1.8V 2-Gb/s scalable low voltage signaling (SLVS) 송신단을 제안한다. 제안하는 송신단은 데이터 전송을 위한 4-lane 송신단, 소스 동기 클록 방식을 위한 1-lane 송신단, 그리고 8-phase 클록 발생기로 구성된다. 제안하는 SLVS 송신단은 50 mV에서 650 mV의 출력 전압 범위를 가지며 고속 동작 모드와 저전력 모드를 제공한다. 또한, signal integrity를 개선하기 위한 출력 드라이버의 임피던스 교정 기법이 제안된다. 제안하는 SLVS 송신단은 1.8 V의 공급 전압을 가지는 0.18-${\mu}m$ 1-poly 6-metal CMOS 공정을 이용하여 구현된다. 구현된 SLVS 송신단의 데이터 jitter의 시뮬레이션 결과는 2-Gb/s의 데이터 전송속도에서 8.04 ps이다. 1-lane을 위한 SLVS 송신단의 면적과 전력소모는 각각 $422{\times}474{\mu}m^2$와 5.35 mW/Gb/s이다.