• Title/Summary/Keyword: 기구합성

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Kinematic Synthesis and Analysis of RSS-SC Suspension System Using Acceptable Tolerances of Motion (운동의 허용공차를 이용한 RSSS-SC 현장장치의 기구학적 설계)

  • 김선평;심재경
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.11
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    • pp.2672-2679
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    • 2000
  • In synthesizing and RSSS-SC mechanism that is the kinematic model of the McPherson strut suspension system in automobiles, the design equations for R-S, S-S and S-C dyads should be solved separately for a given set of prescribed positions. The number of prescribed positions that the RSSS-SC mechanism can be synthesized is up to three because of the S-C dyad. This limitation may cause unsatisfactory results in synthesized joint positions. This paper presents a kinematic synthesis method to place the joints of an RSSS-SC mechanism in desired boundaries by varying the prescribed positions of the mechanism within acceptable tolerances. The sensitivity analysis of the joint positions is used determine which displacement parameter should be altered to fulfill this task.

Synthesis and Characterization of Borosilicate Catalyst (보로실리케이트 촉매의 합성 및 물성에 관한 연구)

  • Kaesoo Lee;Minsoo Cho;Chongsoo Han;Myeongseon Kim;Gon Seo
    • Journal of the Korean Chemical Society
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    • v.33 no.4
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    • pp.379-387
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    • 1989
  • The synthesis of borosilicate consisted of boron and silicon was stadied. The composition, acidity and adsorption characteristics of synthesized borosilicate were examined. The synthesis rate increased with temperature and concentration of $Na_2O$, but the enhansing effects were different according to the reaction conditons. The synthesis process could be simulated by solution transfer mechanism assuming that crystals grow on the surface of crystal or nuclei with dissolved reactant. Adsorption characteristics of synthesized borosilicate was discussed with temperature programmed desorption patterns of ammonia and propylene and adsorption isotherms of propylene and propane.

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Hydrothermal Mechanism of Na-A Type Zeolite from Natural Siliceous Mudstone (규질 이암으로부터 Na-A형 제올라이트 수열합성 반응기구에 대한 연구)

  • Bae, In-Kook;Jang, Young-Nam;Chae, Soo-Chun;Kim, Byoung-Gon;Ryu, Kyoung-Won;Lee, Sung-Ki
    • Journal of the Mineralogical Society of Korea
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    • v.20 no.3
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    • pp.223-229
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    • 2007
  • The mechanism of hydrothermally synthesizing Na-A zeolite from siliceous mudstone at a $Na_2O/SiO_2$ ratio of 0.6, a $SiO_2/Al_2O_3$ 2.0 and a $H_2O/Na_2O$ 119 has been observed by IR, DTA, XRD and SEM. This mudstone is a tertiary periodic sedimentary rock and widely spreads around the Pohang area. In the early hydrothermal synthesis at $80^{\circ}C$ in an autoclave, sodium silicate and sodium aluminate were found to be preferentially reacted to generate Na-A type zeolite. Gibbsite and bayerite were also formed due to the presence of extra aluminum oxide in the feedstock. As reaction time in-creased up to 50 h, residual sodium aluminatewas reacted with siliceous mudstone, causing the Na-A zeolite crystal to grow and the hydroxylsodalite to generate. Therefore, in the $14{\sim}50\;h$ synthetic time, Na-A zeolite and hydroxylsodalite were formed. Also, if reaction time passed over 50 h, a part of the Na-A zeolite was finally redissolved and reacted with hydroxylsodalite to synthesize Na-P zeolite, generating porous surface of Na-A zeolite and disappearing hydroxylsodalite.

Preparation and Performance Evaluation of Zinc Phosphate-Coated Mica Anticorrrosive Pigment (운모상에 인산아연이 도포된 방청안료의 제조 및 성능평가)

  • Lee, Yu Jin;Park, Seong Soo;Hong, Seong Soo;Lee, Seung Ho;Kim, Dae Sung;Lee, Gun Dae
    • Clean Technology
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    • v.19 no.3
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    • pp.257-263
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    • 2013
  • The zinc phosphate-coated mica (ZP/mica) pigments were prepared using phosphoric acid, zinc nitrate and mica as starting materials, and used as anticorrosive pigments. The scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques were used to observe the morphology and crystal structure of prepared pigments. The prepared pigments were incorporated into an epoxy binder to prepare coating and the corrosion inhibition performance of the pigments was evaluated using electrochemical impedance spectroscopy (EIS). It was found that the anticorrosive performance of the ZP/mica pigment prepared at $70^{\circ}C$ was the better than that prepared at $20^{\circ}C$. The formation of ZnO, in addition to $Zn_3(PO_4)_2{\cdot}2H_2O$, was observed on ZP/mica pigment prepared at $70^{\circ}C$. The excellent anticorrosive performance of ZP/mica pigment could be ascribed to the synergistic effect with electrochemical anticorrosive mechanism from zinc compounds on mica and barrier anticorrosive mechanism from lamellar mica.

Synethesis of bradykinin analogues by new reaction vessel (새로운 반응기구에 의한 bradykinin 유사물의 합성)

  • Choi, Cheong
    • Applied Biological Chemistry
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    • v.34 no.4
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    • pp.334-338
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    • 1991
  • Synthesis of $(D-Phe^7\;-Leu^8)$ bradykinin and bradykinin by solid phase method using a new reaction vessel was carried out. Coupling was performed by dicyclohexylcarbodiimide. After cleavage with dried HBr the peptides were purified by high pressure liquied chromatography. Their purify was assayed by paper and thin layer chromatography, melting point and amino acid analysis. $(D-Phe^7\;-Leu^8)$ bradykinin and bradykinin were incubater in vitro endopeptidase $({\alpha}-chymotrysis)$ and exopeptidase(carboxypeptidase A, leucine aminopeptidase) in order to study the degradation pattern of peptides. $(D-Phe^7\;-Leu^8)$ bradykinin and bradykinin were rapidly degradated by ${\alpha}-chymotrypsin$ and carboxypeptidase A $(D-Phe^7\;-Leu^8)$ bradykinin and bradykinin coution$(D-Phe^7\;-Leu^8)$ bradykinin and bradykinin contain imino peptide bound from proline at N-terminal and therefore they were not attacted by leucine aminopeptidase.

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Effect of Mutation in α-COP, A Subunit of the COPI Vesicle, on Cell Wall Biogenesis in Fungi (COPI 소낭 구성체인 α-COP의 돌연변이가 균류 세포벽 합성에 미치는 영향)

  • Lee, Hwan-Hee;Park, Hee-Moon
    • The Korean Journal of Mycology
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    • v.35 no.1
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    • pp.1-10
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    • 2007
  • The cell wall is essential for the survival and osmotic integrity of fungal cells. It is the framework to which biologically active proteins such as cell adhesion molecules and hydrolytic enzymes are attached or within which they act. Recently it was shown that mutations in ${\alpha}-COP$, a subunit of COPI vesicle, is responsible for the thermo-sensitive osmo-fragile phenotype of fungi, such as Saccharomyces cerevisiae and Aspergillus nidulans, and suggested that ${\alpha}-COP$ may play a crucial role in translocation of protein(s) of the ${\beta}-1,3-gulcan$ synthase complex and cell wall proteins, thus may contribute to the maintenance of cell wall integrity. In this review, we summarized the relationship between the intra-cellular protein translocation machinery, especially the ${\alpha}-COP$ of COPI vesicle, and cell wall biogenesis in fungi. We also discussed potential use of secretory mutants in basic and applied research of the fungal cell walls.