• Title, Summary, Keyword: Synthesis

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A study on the speed control system of medium - small size diesel engine by $\mu$-synthesis ($\mu$-synthesis 기법에 의한 중.소형 디젤기관의 속도 제어계에 관한 연구)

  • 양주호;변정환;정병건
    • Journal of the Korean Society of Marine Engineering
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    • v.21 no.1
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    • pp.82-87
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    • 1997
  • This paper presents a method about the modeling of the medium - small diesel engine for the speed control and designs the robust speed control system by the $\mu$-synthesis, which has good performance, in spite of the existence of model uncertainities and the external disturbance. We confirmed the validity of the proposed modeling method and the designed control system by $\mu$-synthesis through the experimental responses.

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Kinetics on Direct Synthesis Dimethyl Ether (디메틸에테르의 직접반응 속도론)

  • Cho Wonihl;Choi Chang Woo;Baek YoungSoon;Row Kyung Ho
    • 한국가스학회:학술대회논문집
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    • pp.83-87
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    • 2005
  • The kinetics of the direct synthesis of DME was studied under different conditions over a temperature range of $220\~280^{\circ}C$, syngas ratio $1.2\~ 3.0$ All experiment were carried out over hybrid catalyst, composed to a methanol synthesis catalyst (Cu/ZnO/$Al_2O_3$) and a dehydration Catalyst ($\gamma$-Al_2O_3$) The observed reaction rate qualitatively follows a Langmiur-Hinshellwood type of reaction mechanism. Such a mechanism is considered with three reaction, methanol synthesis, methanol dehydration and water gas shift reaction. From a surface reaction with dissociative adsorption of hydrogen, methanol and water, individual reaction rate was determined

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Carbon Nanotube Synthesis with High Purity by Introducing of NH3 Etching Gas (암모니아 식각 가스 도입에 의한 고순도 탄소나노튜브의 합성)

  • Lee, Sunwoo;Lee, Boong-Joo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.6
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    • pp.782-785
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    • 2013
  • Multi-walled carbon nanotubes were synthesized on Ni catalyst using thermal chemical vapor deposition. By introducing ammonia gas during the CNT synthesis process, clean and vertically aligned CNTs without impurities could be prepared. As the ammonia gas increased a partial pressure of hydrogen in the mixed gas during the CNT synthesis process, we could control the CNT synthesis rate appropriately. As the ammonia gas has an etching ability, amorphous carbon species covering the catalyst particles were effectively removed. Therefore catalyst particles could maintain their catalytic state actively during the synthesis process. Finally, we could obtain clean and vertically aligned CNTs by introducing $NH_3$ gas during the CNT synthesis process.

Design Space Exploration of Many-Core Architecture for Sound Synthesis of Guitar on Portable Device (휴대 장치용 기타 음 합성을 위한 매니코어 아키텍처의 디자인 공간 탐색)

  • Kang, Myeongsu;Kim, Jong-Myon
    • Proceedings of the Korean Society of Computer Information Conference
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    • pp.1-4
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    • 2014
  • Although physical modeling synthesis is becoming more and more efficient in rich and natural high-quality sound synthesis, its high computational complexity limits its use in portable devices. This constraint motivated research of single-instruction multiple-data many-core architectures that support the tremendous amount of computations by exploiting massive parallelism inherent in physical modeling synthesis. Since no general consensus has been reached which grain sizes of many-core processors and memories provide the most efficient operation for sound synthesis, design space exploration is conducted for seven processing element (PE) configurations. To find an optimal PE configuration, each PE configuration is evaluated in terms of execution time, area and energy efficiencies. Experimental results show that all PE configurations are satisfied with the system requirements to be implemented in portable devices.

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A New Paradigm Shift for the Green Synthesis of Antibacterial Silver Nanoparticles Utilizing Plant Extracts

  • Park, Youmie
    • Toxicological Research
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    • v.30 no.3
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    • pp.169-178
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    • 2014
  • This review covers general information regarding the green synthesis of antibacterial silver nanoparticles. Owing to their antibacterial properties, silver nanoparticles are widely used in many areas, especially biomedical applications. In green synthesis practices, the chemical reducing agents are eliminated, and biological entities are utilized to convert silver ions to silver nanoparticles. Among the various biological entities, natural plant extracts have emerged as green reducing agents, providing eco-friendly routes for the preparation of silver nanomaterials. The most obvious merits of green synthesis are the increased biocompatibility of the resulting silver nanoparticles and the ease with which the reaction can be carried out. This review summarizes some of the plant extracts that are used to produce antibacterial silver nanoparticles. Additionally, background information regarding the green synthesis and antibacterial activity of silver nanoparticles is provided. Finally, the toxicological aspects of silver nanoparticles are briefly mentioned.

Mechanism synthesis of Planar Four-bar Linkage for rigid body guidance by bushing elements (부싱 요소를 이용한 평면 4 절 기구의 강체 유도 기구 합성)

  • Yoo, Hong Hee;Hong, Jung Ryeol
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.464-466
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    • 2014
  • The mechanism synthesis methods, graphical, analytical and computer-aided technique have been proposed for selecting and scaling mechanical system. According to developing computation tools, mechanism could be synthesized much faster and more correct than previous analytical ways by improved techniques. In this paper, the improved synthesis method is proposed to solve body guidance synthesis problem. To perform the mechanism synthesis for body guidance, a planar linkage is modeled as a set of free three bushings located in design space. The values of bushing stiffness and x, y position of bushings yielding a desired functional requirement related to input motion are found by using an optimization technique.

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