• Title/Summary/Keyword: symmetry species

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Polarized Raman Spectroscopic Studies of Syndiotactic Polypropylene (편광 Raman 분광법을 이용한 Syndiotactic Polypropylene에 관한 연구)

  • 진정희;임현주;김성수;송기국
    • Polymer(Korea)
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    • v.26 no.6
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    • pp.745-751
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    • 2002
  • The anisotropic Raman scattering properties of oriented syndiotactic poly propylene have been investigated using FT-Raman spectrometer in which the fluore scent problem of polymer samples can be removed. To assign the observed Raman bands to their respective symmetry species, the anisotropic scattering results for four different combinations of incident and scattered polarization were compared with those predicted by normal coordinate analysis and infrared dichroism measurement data.

Comparative Analysis of T4SS Molecular Architectures

  • Mishghan Zehra;Jiwon Heo;Jeong Min Chung;Clarissa L Durie
    • Journal of Microbiology and Biotechnology
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    • v.33 no.12
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    • pp.1543-1551
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    • 2023
  • The recently published high-resolution R388 T4SS structure provides exciting new details about the complete complex of T4SS, including the components making up the stalk and arches, numerous symmetry mismatches between regions of the complex, and an intriguing interpretation of the closed stalk and radial symmetry of the inner membrane complex, which is related to pilus biogenesis assembly. However, there are a few unidentified densities in the electron microscopy map and portions of the identified component sequences for which the structure is not yet known. It is also unclear how well this minimized DNA-transporting T4SS predicts the structure of other T4SSs, such as expanded systems and those that transport proteins rather than DNA. In this review, we evaluate what can be inferred from the recent high-resolution structure of the R388 T4SS with respect to the Cag and Dot/Icm systems. These systems were selected because, given what is currently known about these systems, we expect them to present most structural differences compared to the R388 T4SS structure. Furthermore, we discuss bacterial physiology and diversity, the T4SS structures and their variations between different bacterial species. These insights may prove beneficial for researchers who elucidate the structure and functions of T4SS in different bacterial species.

Study on formal analysis of carving boards in 'Haejuban' (해주반 판각의 조형분석에 관한 연구)

  • Lee, Yoo-Jin;Lim, Seung-Taeg
    • Journal of the Korea Furniture Society
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    • v.20 no.5
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    • pp.414-430
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    • 2009
  • This paper is designed for the purpose of suggesting Figurative data applicable to modern furniture designs through doing research on Haejuban's engraving that includes excellent Figurative beauty among Korean traditional lighted-floor type furnitures. As a result of the analysis, Haejuban's(Traditional Korean dining table) engraving pattern type was mainly divided into independent patterns and combined patterns. The patterns expressed the most among them are peony patterns. The patterns expressed by the engraving mostly showed the Figurative characteristics of symmetry. The patterns shown in Haejuban's engraving wish or stand for richness, long life, lucky, fidelity, divinity, happiness, success and so on. The species of trees used for Haejuban were a total of 8 kinds such as ginkgo trees, zelkova trees, walnut trees, wild-walnut trees, chinaberry trees and other scrub trees. Ginkgo trees were used the most among them.

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Four New Earthworms of the Genus Amynthas(Oligochaeta: Megascolecidae) from Korea

  • Hong, Yong;Kim, Tae-Heung
    • Animal cells and systems
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    • v.6 no.3
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    • pp.195-199
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    • 2002
  • Four new species of the genus Amynthas are described from Korea: Amynthas mujuensis sp. nov., Amynthas assimilis sp. nov., Amynthas moakensis sp. nov., and Amynthas sangumburi sp. nov. The intestinal caeca are of simple type and genital markings lacking in all four species. Amynthas mujuensis sp. nov. has male field with large oval papillae, each papilla with longitudinal seminal groove; paired spermathecal pores present in 6/7, 7/8 dorsally. Amynthas assimilis sp. nov. has mare field composed of paired symmetrical pear-shaped pads with broad ends laterally, axes of symmetry diagonally oriented towards posterior; spermathecal pores in 5/6, 6/7. Amynthas moakensis sp. nov. has male pores on small porophores surrounded by swollen concentric furrows, with the spermathecal pores in 6/7, 7/8, 8/9, ventrally. Amynthas sangumburi sp. nov. has male pores centered on 0.8 mm circular flat porophores, with the spermathecal pores in 5/6, 6/7, 7/8, 8/9, laterally.

Spore morphology of Korean Polypodiaceae (한국산 고란초과 식물의 포자 형태)

  • Lim, Jin A;Kim, Chul Hwan;Kwak, Min Ju;Sun, Byung-Yun
    • Korean Journal of Plant Taxonomy
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    • v.36 no.1
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    • pp.1-19
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    • 2006
  • Description of spore morphology of Korean Polypodiaceae has on LM and SEM and key to the genera are provided. Korean Polypodiaceae monad, monolete with bilateral symmetry, bipolar and oblete spore except for Loxogramme grammitoides having trilete spore with radial symmetry. In spore wall structure, exopore showed variable patterns enough to distinguish genera. Perispore was found in all the species examined. The patternof perispore and exospore was most similar in all the species examined except Crypsinus, Pyrrosia hastata ans P. linearifolia. The perispores of Crypsinus, Pyrrosia hastata and P. linearifolia were echinate and gemmate, rugulate, and verrucate respectively. In term of exospore wall sculpturing, Polypodium and Loxogramme showed fossulate, Lepisorus, rugulate with irregular verrucate, Crypsinus ans Coloysis showed psilate or rarely verrucate in the latter, Neocheiropteris ensata showed dense small verrucate, Lemmaphyllum microphyllum showed complex reticulate and Pyrrosia showed verrucate or psilate.

Spore morphology of Korean Thelypteridaceae (한국산 처녀고사리과 식물의 포자형태)

  • Moon, Su Mi;Sun, Byung-Yun
    • Korean Journal of Plant Taxonomy
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    • v.38 no.4
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    • pp.459-476
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    • 2008
  • Taxonomic characteristics of spores of 17 species belonging to 6 genera of the Korean Thelypteridaceae are examined. Description of each species and key to the species are provided. Spores of Korean Thelypteridaceae are monad and monolete with bilateral symmetry. Perispore, the sporoderm of spore, was found in all the species examined. The perispores and exospores of Thelypteris japonica var. japonica, T. japonica var. glabrata and Pseudocyclosorus subochthodes are much similar to each other, but the rest of taxa examined shows diverse patterns of the surface ornamentation of perispores and exopores enough to distinguish genera and sometimes to distinguish species in some genera. Previous study reported that perispore is not easily distinguished from exospore in Cyclosorus and Leptogramma. However, three species of Cyclosorus examined here show different pattern having scabrate or verrucate exospores and cristate or echinate perispores. Leptogramma pozoi ssp. mollisima also have echinate perispore and fossulate exospore. Macrothelypteris oligophlebia var. elegans and M. viridifrons have scabrate exospore which is contrast to previous report of reticulate exospore. Thelypteris glanduligera, T. angustifrons and T. laxa show same patterns of perispore and exospore with reticulate perispore and fossulate exospore and hence cannot be distinguished by spores only.

Interplay between Defect Propagation and Surface Hydrogen in Silicon Nanowire Kinking Superstructures

  • Sin, Nae-Cheol
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.221.1-221.1
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    • 2015
  • The vapor-liquid-solid (VLS) method, where the "liquid" catalytic droplets collecting atoms from vapor precursors build the solid crystal layers via supersaturation, is a ubiquitous technique to synthesize 1-dimensional nanoscale materials. However, the lack of fundamental understanding of chemical information governing the process inhibits the rational route to the structural programming. By combining the in situ or operando IR spectroscopy with post-growth high resolution electron microscopy, we show the strong correlation between the surface chemical species concentration and nanowire structures. More specifically, the critical role of surface adsorbed hydrogen, generated from the decomposition of Si2H6 precursor on the interplay between nanowire / kinking and the defect propagation is demonstrated. Our results show that adsorbed hydrogen atoms are responsible for selecting -oriented growth and indicate that a twin boundary imparts structural coherence. The twin boundary, only continuous at / kinks, reduces the symmetry of the trijunction and limits the number of degenerate directions available to the nanowire. These findings constitute a general approach for rationally engineering kinking superstructures and also provide important insight into the role of surface chemical bonding during VLS synthesis.

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Crystallographic Study on Zeolite 4A Reacted with Rubidium Vapor (루비듐 증기와 반응한 제올라이트 4A에 대한 결정학적 연구)

  • Song, Seong-Hwan;Kim, Yang;Han, Young-Wook
    • Journal of the Mineralogical Society of Korea
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    • v.4 no.2
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    • pp.99-107
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    • 1991
  • Three fully dehydrated fully Rb+-exchanged zeolite A single crystals have been prepared by the reduction of all Na+ ions in dehydrated Na12-A by rubidium vapor at various experimental conditions (220 $\leq$ T $\leq$ 33$0^{\circ}C$, 2 $\leq$ t $\leq$24 hours, and 0.1 $\leq$ PRb $\leq$ 1.1 Torr). Their structures were determined by single-crystal X-ray diffraction methods in the space group {{{{ RHO }}m3m (a=12.245(3) A) at 22(1)$^{\circ}C$. In these structures 12.6(2) to 13.5(2) Rb species are found per unit cell, more than the 12 Rb+ ions needed to balance the anionic charge of the zeolite framework, indication that the sorption of Rb0 has occurred. In each structure, three Rb+ ions per unit cell are located at the centers of 8-rings. Beyond that, the fractional occupancies observed are simply explained by two unit cell arrangments. In one, two Rb+ ions are in the sodalite unit near opposite 6-rings, six are in the large cavity near 6-ring, and one is in the large cavity near a 4-ring. In the other, three Rb species in the sodalite cavity (forming a triangle 3.7 A on an edge) each bond (3.4 A) through a 6-ring to an Rb species in the large cavity to give an (Rb6)4+ cluster of symmetry 3m (C3V). Five additional Rb+ ions fill the remaining large-cavity 6-ring sites.

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Distribution of Ions and Molecules Density in N2/NH3/SiH4 Inductively Coupled Plasma with Pressure and Gas Mixture Ratio) (N2/NH3/SiH4 유도 결합형 플라즈마의 압력과 혼합가스 비율에 따른 이온 및 중성기체 밀도 분포)

  • Seo, Kwon-Sang;Kim, Dong-Hyun;Lee, Ho-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.2
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    • pp.370-378
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    • 2017
  • A fluid model of 2D axis-symmetry based on inductively coupled plasma (ICP) reactor using $N_2/NH_3/SiH_4$ gas mixture has been developed for hydrogenated silicon nitride ($SiN_x:H$) deposition. The model was comprised of 62 species (electron, neutral, ions, and excitation species), 218 chemical reactions, and 45 surface reactions. The pressure (10~40 mTorr) and gas mixture ratio ($N_2$ 80~96 %, $NH_3$ 2~10 %, $SiH_4$ 2~10 %) were considered simulation variables and the input power fixed at 1000 W. Different distributions of electron, ions, and molecules density were observed with pressure. Although ionization rate of $SiH_2{^+}$ is higher than $SiH_3{^+}$ by electron direct reaction with $SiH_4$, the number density of $SiH_3{^+}$ is higher than $SiH_2{^+}$ in over 30 mTorr. Also, number density of $NH^+$ and $NH_4{^+}$ dramatically increased by pressure increase because these species are dominantly generated by gas phase reactions. The change of gas mixture ratio not affected electron density and temperature. With $NH_3$ and $SiH_4$ gases ratio increased, $SiH_x$ and $NH_x$ (except $NH^+$ and $NH_4{^+}$) ions and molecules are linearly increased. Number density of amino-silane molecules ($SiH_x(NH_2)_y$) were detected higher in conditions of high $SiH_x$ and $NH_x$ molecules density.

Landscape Plants and Planting Characteristics of Three-Treasure Temples (삼보사찰의 조경식물 및 식재특성)

  • You, Ju-Han;Hong, Kwang-Pyo;Lee, Dong-Hun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.1
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    • pp.119-128
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    • 2010
  • The purpose of this study was to find a basic theory about Korean traditional planting pattern by analyzing a characteristic of planting and planted species in Haein, Tongdo and Songkwang Temples. The results are as follows. The planted species in three-treasure temples were 129 taxa; 57 families, 96 genera, 110 species, 12 varieties and 7 forma. The species related in Buddhism were Viburnum sargentii for. sterile, Hydrangea macrophylla for. otaksa and Musa basjoo. They are related in plant form and Buddhist ceremony. The results of forms were 34.1% in trees, 33.3% in shrubs, 3.9% in vine and 28.7% in herbage. The results of leaf fall were 56 taxa in broad-leaved deciduous trees, 27 taxa in broad-leaved evergreen trees and 14 taxa in needle-leaved evergreen trees. The native species were 32 taxa in Haein Temple, 27 taxa in Tongdo Temple and 44 taxa in Songkwang Temple. And the exotic species were 20 taxa, 28 taxa and 44 taxain the Haein, Tongdo and Songkwang Temples, respectively. In the results of analyzing the characteristics of planting, in the case of Haein Temple, Abies holophylla was linearly planted in Yiljumun, and Magnolia denudata was single planted in plant stairs of Haetalmun. In the case of plant stairs of Jeokmukdang, Cephalotaxus koreana was planted at regular intervals. In the case of Tongdo Temple, Celtis sinensis, Zelkova serrata and so forth were planted in Yiljumun, and Phyllostachys nigra was planted in form of screen planting in Youngsanjeon. The form of Hwanghwagak was a planting of symmetry in the center of a building, and the one of Daekwangmyyeongjeon was a mixed planting. The regular planting pattern was not shown in Yiljumun of Songkwang Temple. In the case of Dosungdang, Corunus officinalis was linearly planted in the west. In the case of Gwaneumjeon, Juniperus chinensis var. globosa and Camellia japonica were planted in symmetry. The old aged trees were planted in front of specimens planted in front of Daewoongbojeon.