• Title/Summary/Keyword: Tetragon

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

  • Jeong, Chil-Hoon;Kim, Heon-Tae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.40 no.1
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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
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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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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Classification into Two Types Based on the Morphological Characteristics of the Marine Diatom Ditylum brightwellii (West) Grunow in Yellow Sea, Korea (우리나라 황해의 해산 돌말류 Ditylum brightwellii (West) Grunow의 형태학적 특징에 의한 두 유형)

  • Lee, Jin-Hwan;Youn, Seok-Jea
    • ALGAE
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    • v.22 no.4
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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.

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

  • Lee Tae-Gyu
    • The Mathematical Education
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    • v.25 no.1
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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
    • Journal of the Semiconductor & Display Technology
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    • v.3 no.3
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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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A Study on Emperor s Costumes during the Reign of Chien-lung in Ching Dynasty (淸代 乾隆朝 『穿戴 案』 服飾硏究)

  • 최경순
    • The Research Journal of the Costume Culture
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    • v.4 no.2
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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
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2004.05a
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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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External and Internal Morphological Standard of Original Plants and Herbal States in Pogostemonis and Agastachis Herba (廣藿香과 土藿香의 外部 및 內部形態硏究)

  • Kang, Jun-hyug;Choi, Jeong;Ju, Young-sung
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.16 no.3
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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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External and Internal Morphological Standard of original plants and herbal states in Pogostemonis and Agastachis Herba (광곽향(廣藿香)과 토곽향(土藿香)의 외부(外部) 및 내부형태연구)

  • Kim, Hong-Jun;Choi, Jeong;Ju, Young-Sung
    • Korean Journal of Oriental Medicine
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    • v.12 no.2 s.17
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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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Formation Mechanism of Columnar Joints at the Sanin Kaigan Geopark in Japan (일본 산인해안지오파크에 분포하는 주상절리의 형성메커니즘)

  • Ahn, Kun Sang
    • Journal of the Korean earth science society
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    • v.39 no.6
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    • pp.575-592
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    • 2018
  • This study investigates the formation mechanism of columnar joints at the Sanin Kaigan Geopark in Japan based on its morphology, rock type and igneous structure. Columnar joints distribute to five areas of three prefectures. That is, Kyogasaki, Byobuiwa, Tateiwa and Kyugenkado in Kyotango area of Kyoto prefecture; Genbudo and Kinumaki Shrine in Toyooka City of Hyogo prefecture; Yoroinosode, Takanosushima, Mini-Yoroinosode in Kamicho Town of Hyogo prefecture; Miooshima and Nagasakihana, Shitaara Domon, Kuzakuishi, Moroyose dyke in Shinonsencho Town of Hyogo prefecture; Shirawara dyke in Iwamicho Town in Tottori prefecture. Igneous structures are divided into three types: lava flow, sill and dyke. Lithologies are divided into five types including basalt, andesite, dacite, rhyolite, and quartz porphyry. Lava flow shows colonnade and entablature. However, entablature is not seen in the sills and dykes in the area. Although the polygons of columnar joint vary from tetragon to octagon, hexagon is most frequently found. The width of colonnades ranges from 10cm to 1m, but their size does not correlate with its $SiO_2$ contents. Meanwhile, their size and morphology at single site are comparatively uniform.