• 제목/요약/키워드: Q&A

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한국산(韓國産) 참나무과(科) 수종(樹種) 도관구조(道管構造)에 관(關)한 연구(硏究)(II) -도관벽(導管壁)의 수식구조(修飾構造)- (A Study on the Vessel Structure of Fagaceae Species in Korea (II) -Micromorphology of Vessel Wall Sculpture-)

  • 이성재;이원용
    • Journal of Forest and Environmental Science
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    • 제8권1호
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    • pp.51-66
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    • 1992
  • This study was carried out to investigate the micromorphology of vessel wall sculpture such as shape of perforation plate, perforation rim, steepness of perforation plate, occurrence of vestured pit, warty layer and ray-vessel pitting on 13 species of Fagaceae in Korea. The results were summarized as follows ; 1. In the species examined, all sample species except Fagus crenata var. multinervis have simple perforation plate. But Fagus crenata var. multinervis has simple and scalariform perforation plate (it was called to combination perforation plate) in a tree stem. 2. The shapes of perforation rim could be classified into five types; Type A without tail, Type B with small tail on both sides, Type C with long tail on both sides, Type D with tail only one side and Type E with the very short interval between perforations. Among five types, Type Band C have higer frequency of distribution than the others. 3. The steepness of perforation plate measured was about 20 degree on pore zone and 43 degree on outside parts of pore zone. 4. Species with vestured pit were Q. aliena, Q, dentata, Q. variabilis, Fagus crenata var. multinervis, Castanopsis cuspidata var sieboldii, Q. acuta, Q. stenophylla, and Q. glauca. But the extent of vesturing was very slight and vestured pits were observed mainly in ray-vessel pit of some vessel elements. 5. Species with warty layer on the inner surface wall of all vessel elements were Q. acuta, Q. stenophylla, Q. glauca, Fagus crenata var. multinervis and species with warty layer of some vessel elements were Q. aliena, Q, dentata, Q. variabilis, Castanopsis cuspidata var. sieboldii. 6. Species with palisade ray-vessel pit were Q. acuta, Q. stenophylla, Q. glauca, Castanea crenata, Castanea bungeana, Q. aliena, Q. serrata, Q. mongolica, and species with scalariform ray-vessel pit was Fagus crenata var. multinervis and species with oval ray-vessel pit were Q, dentata, Castanopsis cuspidata var sieboldii.

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누출 수소 환기에 영향을 미치는 요인별 환기 특성에 관한 수치해석적 연구 (A Numerical Study on Ventilation Characteristics of Factors Affecting Leakages in Hydrogen Ventilation)

  • 이창용;조대환
    • 해양환경안전학회지
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    • 제28권4호
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    • pp.610-619
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    • 2022
  • 수소는 산소와 반응하여 전기에너지를 만들고 부산물로 물을 생성하므로 친환경 선박의 대체 연료로 대두되고 있다. 그러나 수소는 일반 화석연료와는 달리 낮은 점화 에너지와 높은 가연성 범위로 인하여 폭발의 위험성이 높은 물질이다. 그래서 선박에서 사용되는 수소의 안전성을 확보하기 위해서 수소의 누출·확산에 관한 유동 특성을 연구하는 것은 매우 중요하다. 본 연구에서는 선박 내부와 같은 밀폐공간에서 수소가 누출되었을 때 누출량, 통풍량, 환기 방식 등이 환기 성능에 어떤 영향을 미치는지에 대하여 수치적 해석을 수행하였다. 수치해석에는 CFD 상용 소프트웨어인 ANSYS CFX ver 18.1을 이용하였다. 누출량은 1 q = 1 g/s로 하여 1 q, 2 q, 3 q로 변경하였고, 통풍량은 1 Q = 0.91 m/s로 하여 1 Q, 2 Q, 3 Q로 변경하였으며 환기 방식은 typeI, typeII, typeIII로 변경하면서 환기 성능을 분석하였다. 누출량이 1 q에서 3 q로 증가할수록 저장실 내의 수소 몰분율(HMF)는 약 2.4 ~ 3.0배 높게 나타났으며 통풍량 증가는 누출량에 대비하여 약 62.0 ~ 64.8 % 정도 환기 성능이 개선에 효과가 있었다. 그리고 폭발의 위험성을 낮추기 위한 통풍량은 최소 2 Q 이상 되어야 하며, 수소탱크 저장실 내부의 부압 형성을 위해서는 type III가 가장 적합한 방식이라고 판단하였다.

Estimating the Queue Length Distribution of ATM multiplexer using Threshold Bootstrap

  • 김윤배
    • 한국시뮬레이션학회:학술대회논문집
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    • 한국시뮬레이션학회 1999년도 추계학술대회 논문집
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    • pp.62-62
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    • 1999
  • In this paper, we propose a new technique of estimating tail of steady-state queue length distribution; Pr(Q>q), fo ATM multiplexer. Pr(Q>q) is a fundamental measure of network congestion. Assessing Pr(Q>q) properly is crucial for design and control of ATM networks. Data traffic pattern of high-speed networks is highly correlated and bursty. Estimating Pr(Q>q) is very difficult because of correlation and burstiness. We estimate entropy(rate-function) using large deviation principles and threshold bootstrap. Simulation studies are conducted to compare the performance of an existing method and our new method.

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EXPANSIONS OF REAL NUMBERS IN NON-INTEGER BASES

  • Chunarom, Danita;Laohakosol, Vichian
    • 대한수학회지
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    • 제47권4호
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    • pp.861-877
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    • 2010
  • The works of Erd$\ddot{o}$s et al. about expansions of 1 with respect to a non-integer base q, referred to as q-expansions, are investigated to determine how far they continue to hold when the number 1 is replaced by a positive number x. It is found that most results about q-expansions for real numbers greater than or equal to 1 are in somewhat opposite direction to those for real numbers less than or equal to 1. The situation when a real number has a unique q-expansion, and when it has exactly two q-expansions are studied. The smallest base number q yielding a unique q-expansion is determined and a particular sequence is shown, in certain sense, to be the smallest sequence whose corresponding base number q yields exactly two q-expansions.

(p, q)-LAPLACE TRANSFORM

  • KIM, YOUNG ROK;RYOO, CHEON SEOUNG
    • Journal of applied mathematics & informatics
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    • 제36권5_6호
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    • pp.505-519
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    • 2018
  • In this paper we define a (p, q)-Laplace transform. By using this definition, we obtain many properties including the linearity, scaling, translation, transform of derivatives, derivative of transforms, transform of integrals and so on. Finally, we solve the differential equation using the (p, q)-Laplace transform.

ON CHARACTERIZING THE GAMMA AND THE BETA q-DISTRIBUTIONS

  • Boutouria, Imen;Bouzida, Imed;Masmoudi, Afif
    • 대한수학회보
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    • 제55권5호
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    • pp.1563-1575
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    • 2018
  • In this paper, our central focus is upon gamma and beta q-distributions from a probabilistic viewpoint. The gamma and the beta q-distributions are characterized by investing the nature of the joint q-probability density function through the q-independence property and the q-Laplace transform.

nth-order q-derivatives of Srivastava's General Triple q-hypergeometric Series with Respect to Parameters

  • Sahai, Vivek;Verma, Ashish
    • Kyungpook Mathematical Journal
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    • 제56권3호
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    • pp.911-925
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    • 2016
  • We obtain q-derivatives of Srivastava's general triple q-hypergeometric series with respect to its parameters. The particular cases leading to results for three Srivastava's triple q-hypergeometric series $H_{A,q}$, $H_{B,q}$ and $H_{C,q}$ are also considered.

ON A q-ANALOGUE OF THE p-ADIC GENERALIZED TWISTED L-FUNCTIONS AND p-ADIC q-INTEGRALS

  • Lee, Chae-Jang
    • 대한수학회지
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    • 제44권1호
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    • pp.1-10
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    • 2007
  • The purpose of this paper is to define generalized twisted q-Bernoulli numbers by using p-adic q-integrals. Furthermore, we construct a q-analogue of the p-adic generalized twisted L-functions which interpolate generalized twisted q-Bernoulli numbers. This is the generalization of Kim's h-extension of p-adic q-L-function which was constructed in [5] and is a partial answer for the open question which was remained in [3].