• 제목/요약/키워드: field extension

검색결과 1,157건 처리시간 0.027초

Distally-based free anterolateral thigh flap with a modified vena comitans

  • Kang, Chan-Su;Kim, Tae-Gon
    • Archives of Plastic Surgery
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    • 제46권1호
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    • pp.84-87
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    • 2019
  • With the recent development in microsurgery, the use of a perforator flap has been widely implemented. If the length of the ALT flap pedicle is insufficient despite adequate preoperative planning, pedicle length extension is necessary. We planned for a reverse ALT free flap using the distal vessel of the descending branch for pedicle length extension in the case of ALT perforator branch originating from the proximal portion of the descending branch. For the management of venous congestion, the distal venae comitantes were anastomosed to the proximal venous stump in an antegrade manner, successfully resolving the venous congestion. Modified reverse-flow ALT free flap, wherein the venae comitantes are anastomosed to the proximal vein stump, is a good option that allows for relatively simple pedicle extension within the same operative field when securing an adequate pedicle length is difficult because of the origin of the perforator from the proximal descending branch, unlike the initial surgical plan.

타원곡선 암호의 실수체 확장 연산항에 관한 연구 (Study of the Real Number Field Extension Operand of Elliptic Curve Cryptography)

  • 우찬일;구은희
    • 한국산학기술학회논문지
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    • 제15권9호
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    • pp.5790-5795
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    • 2014
  • 타원곡선 암호는 공개키 암호 알고리즘들 중에서 안전도가 매우 우수하여 정보보호 시스템을 구성하는데 있어 매우 중요한 부분으로 자리 잡고 있다. 그러나 타원곡선 암호는 실수체를 사용할 경우 계산이 느리고 반올림에 의한 오차로 인하여 정확한 값을 가질 수 없는 단점이 있어 최근까지 유한체를 기반으로 타원곡선 암호에 대한 연구가 이루어졌다. 만약, 타원곡선 암호를 실수체로 확장할 수 있다면 유한체 만으로 이루어진 타원곡선 암호시스템보다 다양한 키를 선택할 수 있는 장점이 있다. 따라서 본 논문에서는 실수체를 이용한 타원곡선 암호시스템에서 연산항 확장 방법을 사용하여 사용자가 선택할 수 있는 키 값을 보다 다양하게 하여 안전도가 높은 암호시스템을 구축할 수 있는 방법을 제안한다.

토양 미생물 활성과 다양성에 미치는 고추 품종과 퇴비의 단기적 효과 (Short-term Effects of Cultivars and Compost on Soil Microbial Activities and Diversities in Red Pepper Field)

  • 박기춘;권태룡;장길수;김영숙
    • 한국환경농학회지
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    • 제27권2호
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    • pp.139-144
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    • 2008
  • 고추 재배지 포장에서 고추 품종과 퇴비 시용 수준이 토양 미생물 활성과 다양성에 미치는 효과를 검증하고자 본 시험을 실시하였다. 2007년 4월에 퇴비를 30톤과 60톤 $ha^{-1}$을 살포한 다음, 영고4호와 고은 고추를 5월에 정식하였으며 8월 초에 토양을 채취하였다. 토양 미생물 활성은 탈수소 효소활성과 fluorescein diacetate(FDA) 수화도로 측정하였으며, 토양 미생물 군락은 $EcoPlate^{TM}$와 인지질 지방산을 분석하여 조사하였다. 모든 조사 항목에서 품종간 유의성 있는 차이는 발견되지 않았다. 퇴비 30톤과 60톤 $ha^{-1}$처리는 토양의 pH와 미생물 군락을 변화시켰고, 퇴비 60톤 $ha^{-1}$처리는 토양 유기물과 칼리 함량 증가 그리고 탈수소효소 활성과 FDA 수화도 증가에 효과적이었다. 결론적으로 단기적으로는 토양 화학적, 미생물적 특성에 미치는 영향이 고추 재배 품종보다는 퇴비 등의 유기 개량제의 영향이 크지만, 장기적으로 고추재배 품종 특히 '영고4호'가 일반 재배 품종과는 다른 토양 미생물적 특성을 유도할 수 있는 가능성을 보여 주었다.

비접촉식 전류 검출 장치에 관한 연구 (A Study on the Current Detector with Non Contact Type)

  • 김기준
    • 한국전기전자재료학회논문지
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    • 제31권5호
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    • pp.351-356
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    • 2018
  • Commonly, a live-line alarm can be used to measure the electric field strength of a high-voltage system to calculate its current, but it is hard to detect the electric field of shielded cables or concealed structures, such as underground distribution cables. Current sensors can detect the magnetic field in a single core wire, but they cannot determine the magnetic field about a double-core wire because the currents flow in opposite directions. Therefore, it is very difficult to detect certain current problems, such as a fault current in an extension line comprised of a double line. In this paper, to ultimately develop a sensor that can detect the current regardless of line conditions, we used a simulation to determine the concentration of the magnetic field dependent on the distribution of the external magnetic field and the path of each line's core.

2축하중을 받는 직교이방성체내 경사균열진전의 해석 (Analysis of Inclined Crack Extension in Orthotropic Solids Under Biaxial Loading)

  • 임원균;최승룡
    • 대한기계학회논문집A
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    • 제26권6호
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    • pp.993-1000
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    • 2002
  • The objective of this work is to develop the capability to analyze accurately the mixed-mode propagation of a crack in composite structures with elastic orthotropic material stiffness properties and anisotropic material strength characteristics. In order to develop the capability to fully analyze fracture growth and failure in anisotropic structures, we examined the fundamental problem of mixed mode fracture by carrying out the analysis on orthotropic materials with an inclined crack subject to biaxial loading. Our goal here is to include an additional term in the asymptotic expansion of the crack tip stress field and to show that the direction of crack initiation can be significantly affected by that term. We employ the normal stress ratio theory to predict the direction of crack extension. It is shown that the angle of crack extension can be altered by horizontal loads and the use of second order term in the series expansion is important f3r the accurate determination of crack growth direction.

Grouting effects evaluation of water-rich faults and its engineering application in Qingdao Jiaozhou Bay Subsea Tunnel, China

  • Zhang, Jian;Li, Shucai;Li, Liping;Zhang, Qianqing;Xu, Zhenhao;Wu, Jing;He, Peng
    • Geomechanics and Engineering
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    • 제12권1호
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    • pp.35-52
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    • 2017
  • In order to evaluate the grouting effects of water-rich fault in tunnels systematically, a feasible and scientific method is introduced based on the extension theory. First, eight main influencing factors are chosen as evaluation indexes by analyzing the changes of permeability, mechanical properties and deformation of surrounding rocks. The model of evaluating grouting effects based on the extension theory is established following this. According to four quality grades of grouting effects, normalization of evaluation indexes is carried out, aiming to meet the requirement of extension theory on data format. The index weight is allocated by adopting the entropy method. Finally, the model is applied to the grouting effects evaluation in water-rich fault F4-4 of Qingdao Jiaozhou Bay Subsea Tunnel, China. The evaluation results are in good agreement with the test results on the site, which shows that the evaluation model is feasible in this field, providing a powerful tool for systematically evaluating the grouting effects of water-rich fault in tunnels.

Cultural and Rainfall Factors Involved in Disease Development of Fusarium Wilt of Sweet Potato

  • Lee, Yong-Hwan;Cha, Kwang-Hong;Lee, Doo-Goo;Shim, Hyeong-Kwon;Ko, Sug-Ju;Park, In-Jin;Yang, Kwang-Yeol
    • The Plant Pathology Journal
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    • 제20권2호
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    • pp.92-96
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    • 2004
  • Environmental factors such as soil moisture, land management, and weather conditions affecting Fusarium wilt of sweet potato were investigated in major sweet potato cultivation regions in Korea. Fusarium wilt occurred mainly in reclaimed terracing lands, which are flattened and located in hilly to mountainous areas at the base of the mountain, in early seasonal cultivation regions. Disease severity was lower in reclaimed fields with natural slope. The development of Fusarium wilt in the fields was highly correlated with precipitation during planting period (r=-0.96**). Fusarium wilt was more severe in fields with less than 20 cm of available soil depth than in fields with over 20 cm of available soil depth. Greenhouse studies were consistent with field studies that less soil moisture content caused severe Fusarium wilt of sweet potato. These results indicate that low rainfall and moisture of soil with low effective soil depth during planting period are important environmental factors influencing the development of Fusarium wilt.

An Outbreak of Gray Mold Caused by Botrytis cinerea on Kenaf(Hibiscus cannabinus L.)

  • Kwon, Jin-Hyeuk;Kang, Dong-Wan;Lee, Seong-Tae;Shim, Chang-Ki;Kim, Min-Jeong;Kim, Jinwoo
    • 농업생명과학연구
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    • 제50권2호
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    • pp.25-32
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    • 2016
  • A severe outbreak of gray mold on kenaf (Hibiscus cannabinus L.) was observed on kenaf grown in the research field of Gyeongsangnam-do Agricultural Research and Extension Services, Jinju, Korea in 2014. Gray mold appeared on young plants as gray-brown velvety mold covering stems and leaves. Infections that girdled the stem caused wilting above the infected area and developed a canker. The casual fungus formed grayish brown colonies on potato dextrose agar. The conidia were one celled, mostly ellipsoid or ovoid in shape, colorless or pale brown in color, and 6-18 × 4-10 ㎛ in size. The conidiophores were 15-32 ㎛ in length. These measurements and taxonomic characteristics were most similar to those of Botrytis. DNA sequencing and phylogenetic analysis of the complete internal transcribed spacer rRNA gene region confirmed that the fungal isolates were indeed Borytis cinerea. Koch's postulates were supported by pathogenicity tests conducted on healthy plants. On the basis of mycological characteristics and pathogenicity test on host plants, the fungus was identified as Botrytis cinerea. To the best of our knowledge, this is the first report of a gray mold caused by B. cinerea on kenaf in Korea.

근접음장 연속법과 등가 음원법을 이용한 음향홀로그래피 연구 (Study of Acoustic Holography using Equivalent Source Method with Continuation of Acoustic Near-field)

  • 김성훈
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2011년도 추계학술대회 논문집
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    • pp.643-648
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    • 2011
  • This paper deals with the ESM(equivalent source method) with the continuation of acoustic near-field for NAH(near-field acoustic holography) to overcome the finite measurement aperture effect and reconstruct the normal velocity on an arbitrarily shaped structure surface. The continuation method is an extension of the measured sound field into a region outside and is based on the Green's function relating acoustic quantities on the two conformal surfaces. This algorithm is not limited to planar surfaces and can be applied to arbitrarily shaped surfaces. The ESM is an alternative approach of BEM-based NAH for the reconstruction on a general structure. In ESM the acoustic field is represented by a set of point sources located over a surface that is close to the structure surface. The simulation results of this study shows that the reconstruction error of particle velocity on the source surface is 11% and 16% for planar and cylindrical sources separately.

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제초제 저항성 논잡초 발생동향 (Occurrence Trends of Herbicide Resistant Weeds in Paddy Fields in Korea)

  • 이인용;박중수;서영호;김은정;이순계;조승현;권오도;김상국;정완규;박태선;김창석;이정란;문병철;강충길;박재읍
    • 한국잡초학회지
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    • 제32권2호
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    • pp.121-126
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    • 2012
  • 제초제 저항성 논잡초 발생면적은 농촌진흥청 국립농업과학원과 전국 8개 도 농업기술원과 공동으로 조사하였다. 8개 도 농업기술원에서 2011년 8월에 논토양을 채취하여 피라조설퓨론에틸 피리미노박메틸입제를 30kg $ha^{-1}$ 처리하여 설포닐우레아(SU)계 제초제 저항성 논잡초의 발생면적을 추산하였다. 전국 벼 재배면적(유기 및 친환경농업 벼 재배면적 제외)의 20.9%인 167,081ha에서 SU계 저항성 논잡초가 발생되고 있음을 확인하였다. 2008년과 대비하여 본 결과 60,130ha가 늘어났다. 발생비율을 보면, 충청남도가 논 면적의 47.6%로 제일 많이 발생되었고, 그 다음으로는 전라남도로 36.9%, 충청북도 25.7%, 강원도 20.3%, 경기도 13.0% 순이었다. 제초제 저항성 논잡초 중 발생면적이 가장 넓은 초종은 물달개비로서 65,313ha로 전체 39.1%를 차지하였으며, 그 다음으로 올챙이고랭이, 알방동사니 순이었다. 이들 3초종은 전국적으로 고르게 발생하여 제일 문제되는 잡초들이다. 그리고 미국외풀 13,964ha(8.4%), 강피 5.1%이었다.