• Title/Summary/Keyword: Growth of Solid

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Preparation of Self-Assembled Crystalline Microparticles with Bispyridyl Zn-Porphyrin

  • Lee, Da-Hee;Lee, Suk-Joong
    • Bulletin of the Korean Chemical Society
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    • v.33 no.4
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    • pp.1317-1320
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    • 2012
  • Well-defined solid-state microcrystalline structures from bispyridyl Zn-porphyrin have been successfully synthesized. The coordinative interactions between pyridine and Zn are main responsible for this translation of porphyrin molecular building blocks to crystalline microscopic objects. The hexagonal plates are obtained from acetonitrile and rhombus plates are grown from toluene solution. With a simple manipulation during the microcrystal growth, such as growth temperature and time, the morphologies can be controlled by adopting different molecular packing. Consequently, morphologies of microcrystals have been diversified.

Domain Structures of LiNbO3 Single Crystals Grown by Czochralski Method (Czochralski법에 의해 성장시킨 LiNbO3단결정의 Domain Structure)

  • 최종건;오근호
    • Journal of the Korean Ceramic Society
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    • v.25 no.6
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    • pp.699-703
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    • 1988
  • Domain structures of LiNbO3 crystals grown by Czochralski method were examined according to the growth axis and the rotational speed of crystals. Ring shape and split domain structures were revealed in Z-axis and Y-axis grown crystals respectively. It was found that the domain structures of grown crystals were closely related to the solid-liquid interface shape during growth.

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Metalorganic vapor-phase epitaxial growth of vertically well-aligned ZnO nanorods and their photoluminescent properties (수직배향된 산화아연 나노막대의 성장 및 발광특성에 관한 연구)

  • Jeon Yong-Ho;Park Won-Il;Lee Gyu-Cheol
    • Proceedings of the Optical Society of Korea Conference
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    • 2002.07a
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    • pp.174-175
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    • 2002
  • One-dimensional semiconductor nanowires and nanorods have attracted increasing interest due to their unique physical properties and diversity for potential electronic and photonic device applications., Unlike the conventional nanowires fabricated by metal catalyst-assisted vapor-liquid-solid (VLS) method, we developed metalorganic vapor-phase epitaxial (MOVPE) growth for which no catalyst is needed. The structural and photoluminecent properties will also be discussed. (omitted)

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Effects of Flavonoids on Pollen Tube Growth in Arabidopsis thaliana

  • Kim, Young-Soon;Song, Kyu-Sang;Cheong, Hyeon-Sook
    • Journal of Plant Biology
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    • v.39 no.4
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    • pp.273-278
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    • 1996
  • Arabidopsis mutants deficient in flavonoid and sinapate ester (tt4 and fah1-7, respectively) were evaluated in vivo and in vitro to study the possible role of flavonoid compounds in pollen tube growth. In vivo, we investigated pollen tube growth in the pistils of the mutants and wild type(Ler). The growth of pollen tubes was significantly different among the three genotypes. In the fal1-7 pistils, the tubes grew to a greater length relative to those of the wild type or tt4. To examine in vitro pollen tube growth, a solid medium was devised for pollen germination and subsequent growth. In vitro, the identical result was obtained; fahl-7 pollens developed the longest tubes and elongated most rapidly. Therefore, the growth response of pollen tubes to phenolic compounds was examined by adding quercetin or sinapate ester in various concentrations to the media. Quercetin enhanced both germination rate and tube growth in the pollens of the mutants and the wild type, especially in tt4. In contrast, sinapate ester inhibits pollen germination and pollen tube growth in three genotypes. These results suggest that flavonoids and related phenolic compounds have physiological role in the plant reproductive system.

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Y-Ba-Cu-O Single Crystals Growth by Skull Method (스컬(Skull)법에 의한 Y-Ba-Cu-O계 단결정 성장)

  • 정대식;오근호
    • Journal of the Korean Ceramic Society
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    • v.27 no.1
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    • pp.43-47
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    • 1990
  • An attempt was made to grow Y-Ba-Cu-O single crystals by skull method(cold crucible process). Grown YBa2Cu3O7-x(YBC) single crystals were obtained from the upper part of the YBC solid mixture. There were plate-like YBC single crystals aligned with solidified flux along the crystal growth direction. Single crystal size was (5$\times$2$\times$0.2㎣) and was grown to a-b plane of YBC crystal structure which can flow super currents. Optical microscope and X-ray diffraction were employed characterize these microstructure and YBC single crystals.

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Abnormal grain growth of ZnO ceramics (ZnO 세라믹스 거대입성장)

  • Kim, Young Jung
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.29 no.6
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    • pp.251-256
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    • 2019
  • In the process of ZnO ceramic sintering at a temperature of 1385℃, higher than the normal sintering temperature, some grains were growth up to mm scale. When sintered at 1400℃ for 8 hours, the size of the grains that are not involved in the abnormal growth is as large as 30~40 ㎛, but the size of the abnormal grown grain reaches 1,000 ㎛, which is more than 10,000 times bigger in volume than the normal one within 8 hr growth. As a cause of rapid and abnormal grain growth, primary particle size distribution, compaction density variation within sample and doping of impurities could be considered. The primary particle size distribution could be considered main reason for abnormal grain growth but no solid evidence was obtained. Through the observation of the microstructure, it is presumed that the giant grains grow absorbing the neighbor grains through a grain rotation process.

A Study on Win-Win Growth Strategy for Large and Mid-sized IT Service Enterprises (IT서비스 대·중소기업 동반성장 전략 연구)

  • Kim, Hyunsoo
    • Journal of Information Technology Services
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    • v.11 no.3
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    • pp.177-190
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    • 2012
  • The purpose of this research is to find a better win-win growth strategy of Large and mid-sized IT service enterprises. Efficient win-win growth for large and mid-sized enterprises is essential for acquiring a solid global competitiveness in IT service industry. However, previous studies lack generalized and detailed findings, and therefore past strategies were based on fragmented analysis. To develop an efficient win-win growth for Large and mid-sized enterprises, global benchmarking and an in-depth analysis on deep-rooted problems in IT service industry has been conducted. Past and present policies on IT service industry have been reviewed based on desirable co-growth structure. Based on research, current policies are unable to support co-growth, and collaborative efforts between Large and mid-sized enterprises as well as square deals are necessary for win-win growth. A new policy paradigm has been derived and a roadmap for efficient co-growth strategy has been suggested. The results of this research can be used for building a better IT service industry polices. In future studies, a longitudinal analysis on the proposed co-growth strategy can be conducted.

Characteristics of Solid Electrolyte $CO_2$ Gas Sensors (고체전해질을 사용한 $CO_2$가스센서의 응답기구)

  • Kim, G.Y.;Park, Y.P.;Lee, S.I.;Lee, W.J.;Hong, J.W.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.562-564
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    • 2002
  • In recent years, environments of our globe has been getting worse as a result of rapid growth of socioeconomic activities. The global environmental issues of acid rain, green house effect and ozone depletion are caused by various chemical pollutants, emitted from industries, automobiles and home. Most of these pollutants are produced by combustion processes. CO2 as a chief criminal of the greenhouse effect is a main combustion product of fossil fuels. Development of solid-state electrochemical devices for detecting CO2 is demonstrated based on various combination of solid electrolytes and auxiliary sensing materials. The object of this research is to develop various sensor performance for solid electrolyte gas sensor, and to test gas sensor performance manufactured. So we try to present a guidance for developing potential type gas sensor. We concentrated on development of manufacturing process and performance test.

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Synthesis of Au Nanowires Using S-L-S Mechanism (S-L-S 성장기구를 이용한 양질의 골드 나노선 합성)

  • No, Im-Jun;Kim, Sung-Hyun;Shin, Paik-Kyun;Cho, Jin-Woo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.11
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    • pp.922-925
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    • 2012
  • Single crystalline Au nanowires were successfully synthesized in a tube-type furnace. The Au nanowires were grown by vapor phase synthesis technique using solid-liquid-solid (SLS) mechanism on substrates of corning glass and Si wafer. Prior to Au nanowire synthesis, Au thin film served as both catalyst and source for Au nanowire was prepared by sputtering process. Average length of the grown Au nanowires was approximately 1 ${\mu}m$ on both the corning glass and Si wafer substrates, while the diameter and the density of which were dependent on the thickness of the Au thin film. To induce a super-saturated states for the Au particle catalyst and Au molecules during the Au nanowire synthesis, thickness of the Au catalyst thin film was fixed to 10 nm or 20 nm. Additionally, synthesis of the Au nanowires was carried out without introducing carrier gas in the tube furnace, and synthesis temperature was varied to investigate the temperature effect on the resulting Au nanowire characteristics.

Solid-phase refolding of poly-lysine tagged fusion protein of hEGF and angiogenin

  • Park, Sang-Joong;Ryu, Kang;Chai, Young-Gyu;Kweon, Oh-Byung;Park, Seung-Kook;Lee, Eun-Kyu
    • 한국생물공학회:학술대회논문집
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    • 2001.11a
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    • pp.197-203
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    • 2001
  • A fusion protein, consisting of human epidermal growth factor as a recognition domain and human angiogenin as a toxin domain, can be used as a targeted therapeutic against breast cancer cells among others. The fusion protein was expressed as inclusion body in recombinant E. coli, and when the conventional, solution-phase refolding process was used the refolding yield was very low due to severe aggregation, probably due to the opposite surface charge due to vastly different pI values of each domain. Solid-phase refolding process exploiting ionic interactions between the solid matrix and the protein was tried, but the ionic binding yield was very low regardless of the resins and pH conditions used. To provide higher affinity toward the solid matrix, six lysine residues were tagged to the N -terminus of the hEGF domain When the cation exchange resins such as heparin- or CM-Sepharose were used as the matrix, the adsorption capacity increased 2.5-3 times and the subsequent refolding yield increased nearly IS times compared to the conventional process.

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