• 제목/요약/키워드: Tetragon

검색결과 11건 처리시간 0.024초

인공어초 주변의 흐름장에 관한 수치해석 (Numerical Analysis of the Flow Field around Artificial Reefs)

  • 정칠훈;김헌태
    • 한국수산과학회지
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    • 제40권1호
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    • pp.31-38
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    • 2007
  • This study investigated the fluid force acting on an artificial reef and the scour pattern at the bottom of the artificial reef in a steady-flow field using the finite difference method (Flow-3D). The structure was tetragonal in shape, like similar objects found in nature. The numerical analysis showed that the hydrodynamic characteristics and incipient scouring pattern matched natural phenomena. The velocity distribution around the tetragon was symmetric and wake occurred inside the tetragon and behind the bottom of the tetragon. The length of the recirculation flow behind the tetragon for each velocity was about 4-5 cm and the magnitude of the recirculation flow inside the tetragon generally increased with the Reynolds' number, although it decreased slightly for Reynolds' numbers from 11,000 to 12,000. In addition, the total fluid force acting on the tetragon increased with the inflow velocity, although the increment was smaller when the velocity exceed 18 cm/sec. The incipient pattern for the scouring of sediment matched the natural phenomenon.

Hydrogen-bonded Molecular Network of Anthraquinone on Au(111)

  • Kim, Ji-Yeon;Yoon, Jong-Keon;Park, Ji-Hun;Kim, Ho-Won;Kahng, Se-Jong
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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    • pp.107-107
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    • 2011
  • Supramolecular structures of anthraquinone molecules on a metallic surface are studied using scanning tunneling microscope (STM) under ultrahigh-vacuum conditions. When we deposited anthraquinone molecules on Au(111) substrate, the molecules formed three different phases (Chevron type, tetragon type and disordered type) on the surface. Based on our STM measurements, we proposed models for the observed molecular structures. Chevrons are consisted of several molecular chains, which make well-ordered two-dimensional islands by some weak interrow interactions and we could observe tetragon structures which make array of (111) metallic surface. each molecular rows in the chevrons are stabilized by two parallel O-H hydrogen bonds and disordered structures are observed 1-dimensional phase with hydrogen bond. First-principles calculations based on density functional theory are performed to reproduce the proposed models. Distances and energy gains for each intermolecular bond are estimated. In this presentation, we explain possible origins of these molecular structures in terms of hydrogen bonds, Van der Waals interactions and molecule-substrate interactions.

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우리나라 황해의 해산 돌말류 Ditylum brightwellii (West) Grunow의 형태학적 특징에 의한 두 유형 (Classification into Two Types Based on the Morphological Characteristics of the Marine Diatom Ditylum brightwellii (West) Grunow in Yellow Sea, Korea)

  • 이진환;윤석제
    • ALGAE
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    • 제22권4호
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    • pp.253-259
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    • 2007
  • This study deals with the taxonomy of the marine diatom Ditylum brightwellii (West) Grunow: shape, size and ratio, marginal ridge, labiate process, areolation, and seasonal distribution are all considered. Ditylum brightwellii were divided into two type; prism- and cylinder-shaped. Comparisons between specimens from the Yellow Sea were made on, (1) shape- prism types are prismatic-shaped and/or regular square or right-angled tetragon, cylinder types are cylinder-shaped and/or long right-angled tetragon in the girdle view, respectively; (2) size and ratiodiameters of prism types are 82.1 ± 2 μm, while those of cylinder types are 21.2 ± 5 μm and ratio of pervalvar axis/diameter- prism types cells are 1.0-1.5, but cylinder types are 3.9-5.5; (3) marginal ridges- prism types have dotted, while those of the cylinder-type cells have piece, slotted or fimbriated on the marginal ridge; (4) labiate process- both prism- and cylinder-types are central part in valve face, but length of labiate processes of prism types are longer than those of cylinder types; (5) cell margin- the girdle margin show many shallow furrows in prism type and smooth in cylinder type; (6) areolation- both prism- and cylinder-types are a radial pattern in the valve center, but areolae of prism types are larger than those of cylinder types; (7) seasonal distribution- cylinder types are dominated in summer and prism types in the other seasons.

Markov 연쇄를 적용한 확률지도연구 (A study of guiding probability applied markov-chain)

  • 이태규
    • 한국수학교육학회지시리즈A:수학교육
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    • 제25권1호
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    • pp.1-8
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    • 1986
  • It is a common saying that markov-chain is a special case of probability course. That is to say, It means an unchangeable markov-chain process of the transition-probability of discontinuous time. There are two kinds of ways to show transition probability parade matrix theory. The first is the way by arrangement of a rightangled tetragon. The second part is a vertical measurement and direction sing by transition-circle. In this essay, I try to find out existence of procession for transition-probability applied markov-chain. And it is possible for me to know not only, what it is basic on a study of chain but also being applied to abnormal problems following a flow change and statistic facts expecting to use as a model of air expansion in physics.

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Growth and Dissolve of Defects in Boron Nitride Nanotube

  • Lee, Jun-Ha;Lee, Hoong-Joo
    • 반도체디스플레이기술학회지
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    • 제3권3호
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    • pp.23-25
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    • 2004
  • The defect formation energy of boron nitride (BN) nanotubes is investigated using molecular-dynamics simulation. Although the defect with tetragon-octagon pairs (4-88-4) is favored in the flat cap of BN nanotubes, BN clusters, and the growth of BN nanotubes, the formation energy of the 4-88-4 defect is significantly higher than that of the pentagon-heptagon pairs (5-77-5) defect in BN nanotubes. The 5-77-5 defect reduces the effect of the structural distortion caused by the 4-88-4 defect, in spite of homoelemental bonds.

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淸代 乾隆朝 『穿戴 案』 服飾硏究 (A Study on Emperor s Costumes during the Reign of Chien-lung in Ching Dynasty)

  • 최경순
    • 복식문화연구
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    • 제4권2호
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    • pp.207-217
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    • 1996
  • The founding of ching costume system starts from the rule issued in second year of Te-chong reign that the clothing of Manchu people is prohibited to be chinesized. It has undergone many revisions and is officially established in the 37th year of Chien-lung reign. This study is Emperor's costumes during the year in Chien-lung reign. The results are as follows: Emperor's costumes go to the travel are Chi-fu hat and Hsing-fu. Sea-dragon hat changes on otter skin or beaver hat and Ching-rong and ching-ni hat changes velvet hat. Light green informal wear is to be worn once a year. Name of sacrificial robes does not exist in Ching-hui-dien-tu but it take the place of Chao-fu I and Chao-dai II in Chuan-dai-dang-an. Sacrificial robes wear with indigo boots and the other cases wear blue boots and shoes and socks. The shape on ornaments in belt of sacrificial robes is tetragon style.

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Growth and Dissolve of Defects in Boron Nitride Nanotube

  • Jun Ha, Lee;Won Ha, Mun
    • 한국반도체및디스플레이장비학회:학술대회논문집
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    • 한국반도체및디스플레이장비학회 2004년도 춘계학술대회 발표 논문집
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    • pp.59-62
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    • 2004
  • The defect formation energy of boron nitride (BN) nanotubes is investigated using molecular-dynamics simulation. Although the defect with tetragon-octagon pairs (4-88-4) is favored in the flat cap of BN nanotubes, BN clusters, and the growth of BN nanotubes, the formation energy of the 4-88-4 defect is significantly higher than that of the pentagon-heptagon pairs (5-77-5) defect in BN nanotubes. The 5-77-5 defect reduces the effect of the structural distortion caused by the 4-88-4 defect, in spite of homoelemental bonds. The instability of the 4-88-4 defect generates the structural transformation into BNNTs with no defect at about 1500 K.

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eBPF를 활용한 컨테이너 활동 분석 시스템 (eBPF-based Container Activity Analysis System)

  • 김지수;남재현
    • 정보처리학회 논문지
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    • 제13권9호
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    • pp.404-412
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    • 2024
  • 클라우드 환경의 도입은 애플리케이션 배포와 관리 방식을 혁신적으로 변화시켰으며, 마이크로서비스 아키텍처와 컨테이너 기술이 그 중심에 자리 잡고 있다. 그러나 이러한 변화는 마이크로서비스와 같은 복잡한 서비스 환경에서 서비스 간 상호작용을 정확히 파악하고 내부 프로세스를 세밀하게 분석해야 하는 새로운 과제를 제기했다. 기존의 모니터링 기법은 이와 같은 복잡한 환경을 충분히 분석하는 데 한계를 보였으며, 이를 해결하기 위해 최근 eBPF(extended Berkeley Packet Filter) 기술이 주목받고 있다. eBPF는 리눅스 커널에서 발생하는 이벤트를 실시간으로 수집하고 분석할 수 있는 강력한 기술로, 커널 영역에서 발생하는 파일 시스템 활동을 비롯한 다양한 이벤트를 모니터링할 수 있다. 본 논문에서는 이러한 eBPF를 기반으로 한 컨테이너 활동 분석 시스템을 제안하며, 이 시스템이 컨테이너와 호스트 시스템의 커널 영역에서 발생하는 이벤트를 실시간으로 모니터링하고, 수집된 데이터를 분석하는 방법을 제시한다. 또한, eBPF를 활용한 대표적인 컨테이너 모니터링 시스템인 Tetragon, Falco, Tracee를 이벤트 탐지 방식, 기본 정책 적용 여부, 이벤트 유형 식별, 시스템 콜 차단 및 경고 생성 기능 측면에서 비교 분석하여 각 시스템의 장단점을 평가하고, 컨테이너 프로세스 감시 및 제한에 필요한 기능을 파악하였다. 나아가, 본 논문에서는 제안된 시스템을 컨테이너 메타데이터 수집, 내부 활동 모니터링, 시스템 메타데이터 연계의 세 가지 측면에서 설명하고 평가하며, 관련 연구와의 비교를 통해 eBPF 기반 모니터링 시스템의 효용성과 향후 발전 가능성에 대해 논의한다.

廣藿香과 土藿香의 外部 및 內部形態硏究 (External and Internal Morphological Standard of Original Plants and Herbal States in Pogostemonis and Agastachis Herba)

  • 강준혁;최정;주영승
    • 한방안이비인후피부과학회지
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    • 제16권3호
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    • pp.164-184
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    • 2003
  • Objectives : This study was designed to establish a characteristic discrimination of internal and external morphological standard of original plants and herbal states in Pogostemonis and Agastachis Herba. Methods : In this studies, the external-internal morphological standards were determined by using stereoscope and butanol series. Results : 1. The external characteristics: Pogostemon cablin has hairs and brown-like in stem, elliptical fruit. On the other hand, Agastache rugosa has no hairs and red-like in stem, obovatic trigone fruit. 2. The physical characteristics: Pogostemon cablin is gray in whole, has hairs in stem and numerous hairs of ash in leaf. On the other hand, Agastache rugosa is yellow-green in whole, has no hairs in stem. Specially the latter has deep-green colour and numerous hairs presenting mostly at lower epidermis in leaf. 3. The physical characteristics in currents: Pogostemon cablin is brown, has hairs and round-like stem. On the other hand, Agastache rugosa is green or yellow-green, has no hairs and tetragon in stem. 4. The internal characteristics: Pogostemon cablin has progressed spongy tissue in epidermal cell of leaf and many rank of epidermal cell in stem. On other hand, Agastache rugosa has I rank palisade tissue in leaf and few rank of epidermal cell in stem. In the external shape, it was possible that herbs were distinguished according to artificial cIassification and that same genus-degree of relatedness among herbs could be distinguished by more precise and active observation. In the shape of real herbs, I compared current herbs in market with original herbs which were just collected or were on the course of drying. In addition, it was possible that the internal shape could be identified by using microscope after butanol series. Conclusion : Though it was impossible to make distinction of herbs which are not current in my search contents, this search contents will be a standard for applying herbs in the future. An Additional standard establishment including physiochemical reaction and gene research is required in order to supplement the fault of this search.

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광곽향(廣藿香)과 토곽향(土藿香)의 외부(外部) 및 내부형태연구 (External and Internal Morphological Standard of original plants and herbal states in Pogostemonis and Agastachis Herba)

  • 김홍준;최정;주영승
    • 한국한의학연구원논문집
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    • 제12권2호통권17호
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    • pp.75-83
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    • 2006
  • Pogostemonis and Agastachis Herba are the whole of Pogostemon cablin (BLANCO) BENTH or Agastache rugosa (FISCHER et MEYER) O. KUNTZE (family Labiatae) which is produced in all part of Korea and China. This drug is used for removing dampness by means of aromatics in oriental medicine. The standard formula of this drug is important from the viewpoint of the quality control. A characteristic discrimination of internal and external morphological standard in original plants and herbal states of Pogostemonis and Agastachis Herba are as follows. 1. The external characteristics: Pogostemon cablin has hairs and brown-like in stem, elliptical fruit. In the other hand, Agastache rugosa has no hairs and red-like in stem, obovatic trigone fruit. 2. The physical characteristics: Pogostemon cablin is gray in whole, has hairs in stem and numerous hairs of ash in leaf. In the other hand, Agastache rugosa is yellow-green in whole, has no hairs in stem. Specially the latter has deep-green colour and numerous hairs presenting mostly at lower epidermis in leaf. 3. The physical characteristics in currents: Pogostemon cablin is brown, has hairs and round-like stem. In the other hand, Agastache rugosa is green or yellow-green, has no hairs and tetragon in stem. 4. The internal characteristics: Pogostemon cablin has progressed spongy tissue in epidermal cell of leaf and many rank of epidermal cell in stem. In other hand, Agastache rugosa has 1 rank palisade tissue in leaf and few rank of epidermal cell in stem. In the external shape, it was possible that herbs were distinguished according to artificial classification and that same genus-degree of relatedness among herbs could be distinguished by more precise and active observation. In the shape of real herbs, I compared current herbs in market with original herbs which were just collected or were on the course of drying. In addition, it was possible that the internal shape could be identified by using microscope after butanol series. Though it was impossible to make distinction of herbs which are not current in my search contents, this search contents will be a standard for applying herbs in the future. An Additional standard establishment including physiochemical reaction and gene research is required in order to supplement the fault of this search.

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