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Fabrication of SiC/SiC Composites by Reaction Sintering Process (반응소결법에 의한 SiC/SiC 복합재료의 제조)

  • Lee, S.P.;Yoon, H.K.;Kohyama, A.
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.27-31
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    • 2001
  • Hi-Nicalon SiC fiber reinforced SiC composites (SiC/SiC) have been fabricated by the reaction sintering process. Braided Hi-Nicalon SiC fiber with double interphases of BN and SiC was used in this composite system. The microstructures and the mechanical properties of reaction sintered SiC/SiC composites were investigated through means of electron microscopies (SEM, TEM, EDS) and bending tests. The matrix morphology of reaction sintered SiC/SiC composites was composed of the SiC phases that the composition of the silicon and the carbon is different. The TEM analysis showed that the residual silicon and the unreacted carbon were finely distributed in the matrix region of reaction sintered SiC/SiC composites. Reaction sintered SiC/SiC composites also represented proper flexural strength and fracture energy, accompanying the noncatastrophic failure behavior.

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A Study on the Distribution of Tongue Colors and the Correlation of Tongue Colors with the Clinical Laboratory Parameters (설색의 분포 및 설색과 임상병리검사 결과의 연관성에 대한 연구)

  • Yim, Je-Min;Nam, Woo-Jin;Yun, Yong-Jae;Lee, Sang-Min;Kang, You-Gyung;Kim, Won-Il
    • The Journal of Internal Korean Medicine
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    • v.34 no.1
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    • pp.71-85
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    • 2013
  • Objectives : The aim of this study was to evaluate the distribution of tongue color and the correlation of the tongue colors with clinical laboratory parameters. Methods : Statistical analysis on the frequency of each tongue color and the results of the clinical laboratory parameters in each tongue color group. Results : Tongue colors that appeared most frequently were 702c, 695c, 493c, 694c, 701c, 500c, 7432c, 7431c, 7634c, 7419c in that order. Following them, 494c and 507c were rarer colors, and 501c, 673c, 687c, 693c, 696c, 703c, 7418c were equally rarest colors. Among each tongue color group, a significant difference was found in the result of complete blood cell count (CBC). The level of red blood cell (RBC) of 7432c group was significantly higher than that of the other groups except 694c group. The level of hemoglobin (Hb), hematocrit (Hct) of 7432c group were significantly higher than those of all the other groups. The level of RBC of 7431c group was lowest and significantly different from 694c, 7432c group. In results of the other tests were not significantly different. However the level of total cholesterol was higher in 695c, 694c, 500c group, and the level of triglyceride was higher in 500c, 7431c, 694c group. Those four colors have a low chroma and 7431c, 695c take blue violet color. Conclusions : The tongue color is distributed throughout following colors by order of frequency: 702c, 695c, 493c, 694c, 701c, 500c, 7432c, 7431c, 7634c, 7419c, 708c, 494c, 507c, 501c, 673c, 687c, 693c, 696c, 703c, 7418c. Some parameters of CBC has a significant correlation with some tongue colors. Other results including lipid profile, renal function test, and liver function test had no significant difference according to tongue color. However, the colors which have low chroma or take blue violet color tented to be higher in the levels of total cholesterol and triglyceride.

Molecular Species of Triglycerides in Watermelon Seed Oil (수박씨 기름의 triglyceride 분자종에 관한 연구)

  • Chun, Seok-Jo;Park, Yeung-Ho
    • Korean Journal of Food Science and Technology
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    • v.19 no.4
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    • pp.377-381
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    • 1987
  • From the profiles of triglyceride composition and the fatty acid at ${\beta}-position$ of glycerol, triglyceride molecular species were found to be 26 kinds in watermelon seed oil. The major triglyceride molecular species in watermelon seed oil were $C_{18:1}{\cdot}C_{18:2}{\cdot}C_{18:1}$ OLO; 6.4%, $C_{18:0}{\cdot}C_{18:2}{\cdot}C_{18:2}$ SLL; 7.1%, $C_{18:1}{\cdot}C_{18:2}{\cdot}C_{18:2}$ OLL; 16.6%, $C_{16:0}{\cdot}C_{18:2}{\cdot}C_{18:2}$ PLL; 19.6% and $C_{18:2}{\cdot}C_{18:2}{\cdot}C_{18:2}$ LLL; 27.6%, Triglyceride molecular species of watermelon seed oil characterized that LLL species existed more than 27% of the total triglyceride molecular species.

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STUDIES ON THE LIPID OF AQUATIC PRODUCTS (PART 3) Fatty Acid Composition the Lipid in Dried Purple Laver Marketable Products (수산물의 지질에 관한 연구(제3보) -산지별 건해태 지질의 지방산조성에 대하여-)

  • HA Bong Seuk
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.11 no.4
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    • pp.219-225
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    • 1978
  • Several samples of tile dried purple laver grown and processed at the major laver producing districts, i. e Mokpo, Wando, Hadong and Jangrim, along the southern coast of Korea were Quantitatively investigated to determine composing patterns of the fatty acids by gas-liquid chromatography. The total lipid contents in dried purple laver of Hadong were $1.8\%$ being the highest value. Upon analyzing fatty acid composition, some differences were observed in their quantitative distribution at different growing places. Dried purple laver of Wando contained mainly $C_{16:0},\;C_{18:1},\;C_{16:1}\;and\;C_{17:0}$ fatty acids, that of Mokpo contained $C_{16:0},\;C_{20:5},\;C_{18:1}\;and\;C_{16:1}$ fatty acids, and that of Hadong $C_{16:0},\;C_{20:5},\;C_{18:0}\;and\;C_{20:1}$ fatty acids, and that of Jangrim $C_{20:5},\;C_{16:0},\;C_{18:1}\;and\;C_{18:0}$ fatty acids, each in order of acid quantity. In regard to the composing pattern of carbon number of fatty acids, the dried purple laver o Mokpo, Hadong, and Jangrim contained $C_{16},\;C_{18}\;and\;C_{20}$ fatty acids with the identical distributional pattern, while that of Jangrim contained $C_{16},\;C_{18}\;and\;C_{17}$ fatty acids as major components. Dried Purple laver of Jangrim contained especially high amount of $C_{20:5}$ fatty acids.

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Pyrolysis Paths of Polybutadiene Depending on Pyrolysis Temperature

  • Choi Sung-Seen;Han Dong-Hun
    • Macromolecular Research
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    • v.14 no.3
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    • pp.354-358
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    • 2006
  • Polybutadiene (BR) was pyrolyzed at $540-860^{\circ}C$ and the effect of pyrolysis temperature on variations in the relative abundance of the major pyrolysis products (C4-, C5-, C6-, C7-, and C8-species) was investigated. Formation of the C4-, C5-, C6-, and C7-species competed with that of the C8-species. Relative intensity of the C8-species decreased with increasing pyrolysis temperature, while that of the C5-, C6-, and C7-species increased. Pyrolysis paths were became more complicated with increasing pyrolysis temperature. We suggested the operation of double bond migration and succeeding rearrangements for the formation of the C5- and C7-species and various rearrangements, including a double bond, for the formation of the C6-species at high temperature. The activation energies for the pyrolysis product ratios of(C5+C6+C7)/C4 and C8/C4 were used to explain the competition reactions to form the pyrolysis products.

CHARACTERIZING FUNCTIONS FIXED BY A WEIGHTED BEREZIN TRANSFORM IN THE BIDISC

  • Lee, Jaesung
    • Korean Journal of Mathematics
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    • v.27 no.2
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    • pp.437-444
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    • 2019
  • For c > -1, let ${\nu}_c$ denote a weighted radial measure on ${\mathbb{C}}$ normalized so that ${\nu}_c(D)=1$. For $c_1,c_2>-1$ and $f{\in}L^1(D^2,\;{\nu}_{c_1}{\times}{\nu}_{c_2})$, we define the weighted Berezin transform $B_{c_1,c_2}f$ on $D^2$ by $$(B_{c_1,c_2})f(z,w)={\displaystyle{\smashmargin2{\int\nolimits_D}{\int\nolimits_D}}}f({\varphi}_z(x),\;{\varphi}_w(y))\;d{\nu}_{c_1}(x)d{\upsilon}_{c_2}(y)$$. This paper is about the space $M^p_{c_1,c_2}$ of function $f{\in}L^p(D^2,\;{\nu}_{c_1}{\times}{\nu}_{c_2})$ ) satisfying $B_{c_1,c_2}f=f$ for $1{\leq}p<{\infty}$. We find the identity operator on $M^p_{c_1,c_2}$ by using invariant Laplacians and we characterize some special type of functions in $M^p_{c_1,c_2}$.

Taxonomic Study on Cirsium Miller (Asteraceae) in Korea Based on External Morphology (외부형태형질에 의한 한국산 엉겅튀속(Cirsium Miller)의 분류학적 연구)

  • Song, Mi-Jang;Kim, Hyun
    • Korean Journal of Plant Taxonomy
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    • v.37 no.1
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    • pp.17-40
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    • 2007
  • Patterns of morphological variation in Korean Cirsium were examined using numerical analysis, and the delimitation of taxa was evaluated. Principal components analysis of individuals of taxa using 61 morphological characters revealed the presence of two major groups. One group included C. lineare, C. vlassovianum, and C. setidens, the other contained C. pendulum, C. japonicum var. japonicum, C. japonicum var. spinosissimum, C. schantarense, C. nipponicum, and C. rhiniceros. Also, the result of cluster analysis recognized three sections, Onotrophe, Pseudo-eriolepis, and spanioptilon. Korean Cirsium was classified into three sections; C. japonicum var. japonicum, C. japonicum var. spinosissimum, C. schantarense, C. rhiniceros and C. nipponicum were belonged to sect. Onotrophe, C. setidens, C. vlassovianum and C. lineare were belonged to sect. Spanioptilon, and C. pendulum was belonged to sect. Pseudo-eriolepis. In conclusion, Korean Cirsium was classified into three sections, eight species, three varieties, and five forms.

Triacylglycerol composition of dry peas (Pisum sativum L.) (완두의 트리아실글리세롤 조성)

  • Kwon, Yong-Ju;Yoo, Jae-Soo;Whang, Young-Tae;Kim, Choong-Ki;Song, Geun-Seoup
    • Applied Biological Chemistry
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    • v.34 no.2
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    • pp.81-85
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    • 1991
  • Lipids in dry peas were extracted by the mixture of chloroform-methanol-water, and from the extracted lipids triacylglycerols(TG) were separated by thin layer chromatography. TG were separated into different fractions according to partition numbers by HPLC. Each of these collected fractions was analyzed on the basis of acyl carbon number by GLC, and their fatty acid compositions were also analyzed by GLC. From these results, the possible fatty acid combinations of TG in dry peas were estimated to be thirty three kinds and the major kinds were as follows $C_{16:0}C_{18:2}C_{18:2}(13.4%),\;C_{18:1}C_{18:2}C_{18:3}(9.3%),\;C_{18:1}C_{18:2}C_{18:2}(9.2%),\;C_{18:2}C_{18:2}C_{18:2}(8.1%),\;C_{18:2}C_{18:2}C_{18:3}(6.4%),\;and\;C_{18:0}C_{18:1}C_{18:2}(5.4%)$.

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Taxonomy and distribution of Corycaeidae (Copepoda: Cyclopoida) in the Korean Waters in Summer (한국 연근해에서 하계에 출현하는 Corycaeidae (Copepoda : Cyclopoida)의 분류 및 분포)

  • KANG, YOUNG SHIL;HUH, SUNG-HOI;LEE, SAM SEUK
    • 한국해양학회지
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    • v.25 no.2
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    • pp.49-61
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    • 1990
  • The family Corycaeidae in the neighbouring seas of Korea was taxonomically studied based on the zooplankton samples collected in August, 1986. In this study, nine species belonging to two genera and three subgenera of the Corycaeidae were identified and described with illustrations; Corycaeus (Corycaeus) speciosus, G.(C.) crassiusculus, C. (Ditrichocorycaeus) affinis, C.(D.) andrewsi, C.(D.) erythraeus, C.(Onychocorycaeus) pacificus, c.(O.) catus, C.(O.) agilis, and Farranula gibbula. The distribution patterns of these species showed that C.(D.) affinis appeared to be and indicator species of the coastal waters, and C.(C.) speciosus, C.(C.) crassiusculus, c.(O.) catus, C.(D.) andrewsi, and Farranula gibbula appeared to be indicator species of the warm-oceanic waters.

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Interface formation and thermodynamics between SiC and thin metal films (SiC와 금속박막간의 계면형성 및 열역학)

  • Chang-Sung Lim;Kwang-Bo Shim;Dong-Woo Shin;Keun-Ho Auh
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.6 no.1
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    • pp.62-72
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    • 1996
  • The interface formation and reaction-product morphology between SiC and thin metal films were studied at temperatures between 550 and $1450^{\circ}C$ for various times. The typical reaction layer sequence was CoSi/CoSi+C/CoSi/CoSi+C/ $\cdots$ /SiC reaction at 1050 and $1250^{\circ}C$ for 2 h, while $Ni_2Si/Ni_2Si+C/Ni_2Si/Ni_2Si+C/ {\cdots} /SiC$ at 950 and 105$0^{\circ}C$ for 2 h. Carbon precipitated preferentially on the outer surface and crystallized as graphite above $1450^{\circ}C$ for SiC/Co reaction zone and $1250^{\circ}C$ for SiC/Ni. The mechanism of the periodic band structure formation with carbon precipitation behaviour was discussed in terms of thermodynamic considerations.

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