• 제목/요약/키워드: Synthesis mechanism

검색결과 995건 처리시간 0.304초

Synthesis and characterization of nanocrystalline Al0.5Ag0.5TiO3 powder

  • Kumar, Sandeep;Sahay, L.K.;Jha, Anal K.;Prasad, K.
    • Advances in nano research
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    • 제1권4호
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    • pp.211-218
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    • 2013
  • A low-cost, green and reproducible citric acid assisted synthesis of nanocrystalline $Al_{0.5}Ag_{0.5}TiO_3$ (n-AAT) powder is reported. X-ray, FTIR, energy dispersive X-ray, transmission electron microscopy and scanning electron microscopy analyses are performed to ascertain the formation of n-AAT. X-ray diffraction data analysis indicated the formation of monoclinic structure. Spherical shaped particles having the sizes of 3-15 nm are found. The mechanism of nano-transformation for the soft-chemical synthesis of n-AAT has been explained using simple organic chemistry rules and nucleation and growth theory. Dielectric study revealed that AAT ceramic might be a suitable candidate for capacitor applications.

Analysis of Vibration Transmissibility for Compressor of Refrigerator by Vector Synthesis Method (벡터합성법에 의한 냉장고 압축기의 진동전달 해석)

  • 오재응;조준호;김진동
    • Transactions of the Korean Society of Mechanical Engineers
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    • 제19권1호
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    • pp.14-21
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    • 1995
  • General Mechanical Structures have various and complex vibration transmission paths. In order to identify the mechanism of vibration transmission. The correct estimation of exciation forces and the exact modeling of transmission paths are required. In this paper, vector synthesis technique is employed to identify the characteristics of vibration input and it's transmission to body structure for the mounting system of a compressor in a refrigerator. Vibration reduction efficiency of each transmission path is evaluated by comparing individual vector components obtained before and after the paths from experimental research. The degree of effect is used to estimate the contribution of vibration input components to total output. And this paper presents a new technique based on simulation studies using vector synthesis dragram, by which the effects of change of the magnitude and phase of transmission paths can be predicted.

Evaluation of the Inputs Efficiency for the Interior Noise of the Vehicle using Vector Synthesis Method (벡터합성법을 이용한 차량 실내소음의 입력원 영향도 평가)

  • Yang, In-Hyung;Jeong, Jae-Eun;Oh, Jae-Eung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • 제20권6호
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    • pp.562-567
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    • 2010
  • A passenger vehicle has various and complicated transmission paths of sound and vibration. In order to identify the mechanism of transfer path, estimation of excitation force and exact modeling of transfer path are required. In this paper vector synthesis technique is employed to identify the characteristics of road noise and its transmission to vehicle compartment through noise and vibration analysis. Vibration reduction efficiency of each transfer path is evaluated by comparing individual vector components obtained virtual simulation. The degree of effect is used to estimate the contribution of vibration input components to total output. And in this paper presents a new technique based on simulation studies using vector synthesis diagram and design of experiments, by which the effects of magnitude and phase change of input paths can be predicted.

Peculiarities of SHS and Solid State Synthesis of ReBa2Cu3O7-x Materials

  • Soh, Deawha;Natalya, Korobova
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제15권3호
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    • pp.275-280
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    • 2002
  • The peculiarities of using Self-propagating High-temperature Synthesis (SHS) and solid-stave chase synthesis for production of high temperature superconductor materials were discussed. Oxide superconductors with general formula of $ReBa_2Cu_3O_{7-x}$ (Re=Y, Sm) haute been made by using barium oxide initial powder instead of traditional barium carbonate. Phenomena observed during the grinding of the reactants mixture are presented. Mechano-chemical activation - as a pre-treatment of the reactants mixture - strongly influences the kinetic parameters, the reaction mechanism, and the composition and structure of the final product.

Can animals too negotiate nano transformations?

  • Jha, Anal K.;Prasad, K.
    • Advances in nano research
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    • 제1권1호
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    • pp.35-42
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    • 2013
  • Cockroach (Periplaneta americana) broth has been employed to assess its potential as a candidate source animal tissue for the synthesis of gold nanoparticles. The synthesis is performed akin to room temperature in the laboratory ambience. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of nanoparticles. The synthesis of nanoparticles might have resulted due to the activity of chitin, metallothioneine and tropomyosin. A possible involved mechanism for the biosynthesis of nanoparticles has also been proposed. This work further indicates that the animal wastes too can effectively participate in nano-transformations thereby helping in controlling the environmental pollution and subsequently the different diseases.

THERMAL PLASMA SYNTHESIS OF NANO-SIZED POWDERS

  • Seo, Jun-Ho;Hong, Bong-Guen
    • Nuclear Engineering and Technology
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    • 제44권1호
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    • pp.9-20
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    • 2012
  • A brief review on the thermal plasma synthesis of nano-sized powders is presented according to the application materials, such as, metals, ceramics, glasses, carbonaceous materials and other functional composites, such as, supported metal catalyst and core-shell structured nano materials. As widely adopted plasma sources available for thermal plasma synthesis of nanosized powders, three kinds of plasma torches, such as transferred and non-transferred DC and RF plasma torches, are introduced with the main features of each torch system. In the basis of the described torch features and the properties of suggested materials, application results including synthesis mechanism are reviewed in this paper.

BSCCO Superconducting Powder by SHS

  • Soh, Dea-Wha;Cho, Yong-Joon;Korobova, N.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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    • pp.99-102
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    • 2002
  • The BSCCO superconductor materials of using Self-propagating High-temperature Synthesis (SHS) were studied. Mechano-chemical activation - as a pre-treatment of the reactants mixture - strongly influences the kinetic parameters, the reaction mechanism, and the composition and structure of the final product. In this paper as an effort for fabricating the SHSed BSCCO superconductor powder SHS method was considered to application in the synthesis of superconducting materials.

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Synthesis of Novel 3-Aminohydantoinyl-1.2-benzothiazine Derivatives for the COX-2 inhibitors

  • Park, Myung-Sook;Lee, Myung-Sook;Shin, Hae-Soon;Kwon, Soon-Kyoung
    • Proceedings of the PSK Conference
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.344.1-344.1
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    • 2002
  • We report the synthesis of several new 3-aminohydantoinyl-1.2-benzothiazine derivatives and propose an another mechanism of the cyclization to the hydantoins for the development candidates of COX-2 inhibitors. 3-Aminohydantoins 3a-d were prepared through cyclization of the condensation products that were formed by heating amino acids and tert-bytyl carbazate in quinoline according to the method of Lalezari. (omitted)

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