• Title/Summary/Keyword: 핵형성

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Effect of hydrogenation surface modification on dispersion and nucleation density of nanodiamond seed particle (수소화 표면 개질이 나노다이아몬드 seed 입자의 분산 및 핵형성 밀도에 미치는 영향)

  • Choi, Byoung Su;Jeon, Hee Sung;Um, Ji Hun;Hwang, Sungu;Kim, Jin Kon;Cho, Hyun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.29 no.6
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    • pp.239-244
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    • 2019
  • Two hydrogenation surface modifications, namely hydrogen atmosphere heat treatment and hydrogen plasma treatment, were found to lead to improved dispersion of nanodiamond (ND) seed particles and enhanced nucleation density for deposition of smooth ultrananocrystalline diamond (UNCD) film. After hydrogenation, the C-O and O-H surface functionalities on the surface of nanodiamond particles were converted to the C-H surface functionalities, and the Zeta potential was increased. As the degree of dispersion was improved, the size of nanodiamond aggregates decreased significantly and nucleation density increased dramatically. After hydrogen heat treatment at 600℃, average size of ND particles was greatly reduced from 3.5 ㎛ to 34.5 nm and a very high nucleation of ~3.9 × 1011 nuclei/㎠ was obtained for the seeded Si surface.

Enhanced nucleation density by heat treatment of nanodiamond seed particles (나노다이아몬드 seed 입자의 열처리에 의한 핵형성 밀도 향상)

  • Park, Jong Cheon;Jeong, Ok Geun;Son, Bit Na;Cho, Hyun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.23 no.6
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    • pp.291-295
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    • 2013
  • Surface chemical modification via air and hydrogen heat treatment was found to relieve the aggregation of nanodiamond (ND) seed particles and lead to a significantly enhanced nucleation density for ultrananocrystalline diamond (UNCD) film growth. After heat treatment in air and hydrogen, modification of surface functionalities and increase in the zeta potential were observed. Mean size of the ND aggregates was also dramatically reduced from ${\sim}2{\mu}m$ to ~55 nm. Si surface seeded with ND particles heat-treated at $600^{\circ}C$ in hydrogen produced a much higher nucleation density of ${\sim}2.7{\times}10^{11}cm^{-2}$ compared to untreated ND seeds.

Karyotypes of the Korean birds 1. Karyological analysis on four species of genus Pans by conventional Giemsa staining method. (한국산 조류의 핵형 1. 일반염색 방법에 의한 박새속 4종의 핵형분석)

  • 이성근;이혜영
    • The Korean Journal of Zoology
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    • v.32 no.4
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    • pp.358-364
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    • 1989
  • 한국산 박새속 조류 Porus major(박새), Porus atter(진박새), Porus poiustris(쇠박새), Parus varius(곤줄박이)의 핵형을 일반염색 방법으로 분석한 결과 4종의 염색체 수는 모두 2n=78∼80으로 나타났고, 성 염색체를 포함한 7쌍이 macrochromosome, 그 외 32∼33쌍이 microchromosome이었다. 종간 차이를 나타내는 염색체는 5번째 염색체와성염색체인 Z·W-염색체였다. 이러한 핵형의 차이는 5번째 염색체에서는 pericentric inversion, 성 염색체에서는 전좌에 의한 것으로 생각된다. The chromosomal analysis of Pows major, Paws after, Paws palustris and Paws vorius of the genus Paws in Korea were performed by conventional Giemsa staining method. The diploid number of four species were 2n=78-80, and there were 7 pairs of macrochromosomes and 32 or 33 pairs of microchromosomes. The 5th and Z·W-chromosomeswere distinctly different between interspecies. Probably these karyological differences were speculated by pericentric inversion in 5th chromosome and translocation in Z·W-chromosomes.

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Manufacture and Characterization of Low Firing Temperatur Substrate using Glass Ceramics with Fluorine (Fluorine 함유 Glass Ceramics를 이용한 저온 소결기판 제조 및 기판의 특성 평가)

  • 강원호
    • Journal of the Microelectronics and Packaging Society
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    • v.3 no.2
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    • pp.27-38
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    • 1996
  • Lithium fluorhectorite 결정상을 함유한 glass ceramics 분말의 형성과 제조된 glass ceramics 분말을 이용한 저온 소결기판의 특성평가를 하였다. Li2O-MgO-MgF2-SiO2 계 유 리로 핵형성 및 결정 성장을 실시하여 lithium fluorhectorite 결정상을 지닌 glass ceramics 를 제조하였다. 유리시편의 핵형성 온도는 46$0^{\circ}C$였고 결정성장온도는 600, 640, 110$0^{\circ}C$에서 나타났다. $600^{\circ}C$에서의 결정상으 Li2.4LiSi4O10F2가 나타났다. Li2.4Mg8LiSi4와 Li2.8Mg0.6SiO4은 lithium fluorhectorite 결정상으로 되기 위한 중간상임을 확인할수 있었다. 64$0^{\circ}C$에서 열처리 후 110$0^{\circ}C$에서 재열처리하여 형성된 결정은 lithium fluorhectorite 와 tridymite가 최종 결정 상으로 나타났다. 이것은 수중에서 water swelling 현상에 의하여 분말화할 수 있었다, 기판 제조용 slurry를 제조하기 위해 glass ceramics 분말에 Al2O3분말을 0,25,50wt%로 혼합한것 과 glass ceramics 분말에 potashborosilica-te glass 분말을 15, 30, 45, 60 wt% 로 배합하 여 doctor blade 법으로 green sheet를 제조하였다. green sheet 는 950~150$0^{\circ}C$로소성하여 기판의 특성을 평가하였다. 겉보기 기공율은 3.06~19,14%이었고, 전기적 특성으로 유전상수 는 3~5(100KHz)를 나타내었다.

Fabrication of Low Temperature Cofiring Substrate Containing Fluorine by Water Swelling (Water Swelling을 이용한 Fluorine함유 저온소결 기판의 제조)

  • 윤영진;최정헌;이용수;강원호
    • Journal of the Microelectronics and Packaging Society
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    • v.9 no.2
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    • pp.19-25
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    • 2002
  • Glass composed of $Li_2$O.MgO. $MgF_2$.$SiO_2$.$B_2O_3$ for the fabrication of green sheet was prepared by melting process, and glass ceramics was prepared by the process of nucleation and grystal growth for the glass of $Li_2$O.MgO. $MgF_2$.$SiO_2$.$B_2O_3$ system with Lithium fluorhectorite and Lithium boron fluorphlogopite crystal phase. Powderization of the glass ceramics was carried out by water swelling. The average particle size at this point was 2.574 $\mu\textrm{m}$. Slurry was prepared for green sheet using high viscous sol fabricated by water swelling, which shows cleavage phenomenon in prepared glass ceramics. The optimum ratio of powder to water for the tape casting was 18:100, and its viscosity was 11,000~14,000 cps.

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Electrophoretic karyotype of Flammulina velutipes and its variation among cultivars (팽이버섯의 핵형분석과 균주 사이의 핵형 다양성)

  • Lee, Song Hee;Lee, Mi-Kyoung;Kim, Na-Ri;Lee, Chang-Yun;Lee, Hyun-Sook
    • Journal of Mushroom
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    • v.12 no.1
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    • pp.63-66
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    • 2014
  • The karyotype of F. velutipes Korean cultivar, Fv 3-6, was compared with those of Japanese cultivars, Fv 0-1, Fv 1-5, Fv 11-1, by CHEF gel electrophoresis. The Korean cultivar, Fv 3-6, showed the difference from the three Japanese cultivars in number and size of chromosomes; the Fv 3-6 had two and one more chromosomes then Fv 0-1 and Fv 11-4, and Fv 1-5 had, respectively. The karyotyping by CHEF gel electrophoresis is quite suitable to define new Korean cultivars against Japanese cultivars.

The crystallization behaviours of cordierite gel derived from sil-gel method and glass prepared by the conventional melting method. (용융법과 졸겔법으로 제조된 Cordierite 계 유리와 겔의 결정화 거동)

  • Park, Won-Gyu
    • The Journal of Engineering Research
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    • v.1 no.1
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    • pp.15-22
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    • 1997
  • The crystallization behaviours of cordierite gel derived from sol-gel method and glass prepared from conventional melting method with or without $TiO_2$ as nucleants are compared. The densification temperature of gel is $810^{\circ}C$ and its chemical structure identified by IR analysis is same as that of glass melted by conventional method. The beginning crystallization temperature of gel is $965^{\circ}C$ lower than that of melted glass with 10wt% $TiO_2$, which is $978^{\circ}C$. The crystalline phases developed from gel during heat treatment are identified as spinel, $\beta$-quartz solid solution and $\alpha$-cordierite crystal and crystalline phases in case of glass are (Mg,Al)TiOn and $\beta$-quartz solid solution and $\alpha$-cordierite crystal, respectively. The crystallization in melted glass with nucleants occurs through bulk crystallization and in case of that without nucleants surface crystallization occurs, while the crystallization in gel is internal crystallization from interface between particles formed after densification.

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Correlation between Karyotype and Phenotype in Turner Syndrome (터너증후군의 핵형과 표현형간의 연관성)

  • Shim, Ye-Jee;Hwang, Young-Ju;Lee, Kun-Soo
    • Journal of Genetic Medicine
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    • v.6 no.1
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    • pp.67-73
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    • 2009
  • Purpose : In spite of the karyotype and phenotype diversity in Turner syndrome patients, there are few reports about such differences in Korea. We reviewed the data of chromosome abnormalities, clinical manifestations, and comorbidities of Turner syndrome patients in Kyungpook National University Hospital to compare them to the recent hypotheses about sex chromosome gene loci related to Turner symptoms. Materials and Methods : We identified the cytologic findings of 92 patients with Turner syndrome and the clinical findings of 62 patients among them. Results : 54.3 percent of patients had 45,X while 45.7 percent showed other karyotype combinations (45,X/46,XX, 45,X/46,XX/47,XXX, 46,X,del(Xp), 46,X,del(Xq), 45,X/46,X,del(Xq), 46,X,i(Xq), 45,X/46,X,i (Xq)). The Turner symptoms found included short neck, high arched palate, broad chest, Madelung deformity, short metacarpals, scoliosis, cubitus valgus, low hair line, webbed neck, edematous extremities, pigmented nevus, and sexual infantilism. The specific diseases associated Turner syndrome included renal abnormalities, congenital heart disease, hearing defects, diabetes mellitus, hyperlipidemia, and decreased bone density. The phenotype of the mosaicism group was milder than that of the monosomy group. In the case of 46,X,del(Xp) and 45,X/46,X,del(Xq) groups, all had skeletal abnormalities, but the 46,X,del(Xq) group had none. In the case of 46,X,del(Xp) group, all showed short statures and skeletal abnormalities, but no sexual infantilism was observed. In the case of 46,X,i(Xq) and 45,X/46,X,i(Xq) groups, they all showed delayed puberty and had primary amenorrhea. Conclusion : It is important to study karyotype-phenotype correlations in patients with Turner syndrome to obtain interesting information about the genotype-phenotype correlations related to the X chromosome.

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