• Title/Summary/Keyword: STI

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Diffusion coefficient estimation of Si vapor infiltration into porous graphite

  • Park, Jang-Sick
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.190.1-190.1
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    • 2015
  • Graphite has excellent mechanical and physical properties. It is known to advanced materials and is used to materials for molds, thermal treatment of furnace, sinter of diamond and cemented carbide tool etc. SiC materials are coated on the surface and holes of graphite to protect particles emitted from porous graphite with 5%~20% porosity and make graphite hard surface. SiC materials have high durability and thermal stability. Thermal CVD method is widely used to manufacture SiC thin films but high cost of machine investment and production are required. SiC thin films manufactured by Si reaction liquid and vapore with carbon are effective because of low cost of machine and production. SiC thin films made by vapor silicon infiltration into porous graphite can be obtained for shorter time than liquid silicon. Si materials are evaporated to the graphite surface in about $10^{-2}$ torr and high temperature. Si materials are melted in $1410^{\circ}C$. Si vapor is infiltrated into the surface hole of porous graphite and $Si_xC_y$ compound is made. $Si_x$ component is proportional to the Si vapor concentration. Si diffusion coefficient is estimated from quadratic equation obtained by Fick's second law. The steady stae is assumed. Si concentration variation for the depth from graphite surface is fitted to quadratic equation. Diffusion coefficient of Si vapor is estimated at about $10^{-8}cm^2s^{-1}$.

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Steering Control of Differential Brake System using Fuzzy Algorithm (퍼지 알고리즘을 이용한 차동 브레이크 시스템의 조향제어)

  • 윤여흥;제롬살랑선네;장봉춘;이성철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.233-237
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    • 2002
  • Vehicle Dynamics Control(VDC) has been a breakthrough and become a new terminology for the safety of a driver and improvement of vehicle handling. This paper examines the usefulness of a brake steer system (BSS), which uses differential brake forces for steering intervention in the context of VDC. In order to help the car to turn, a yaw moment can be achieved by altering the left/light and front/rear brake distribution. The steering function achieved through BSS can then be used to control lateral position in an unintended road departure system. A 8-DOF non-linear vehicle model including STI tire model will be validated using the equations of motion of the vehicle, and the non-linear vehicle dynamics. Since Fuzzy logic can consider the nonlinear effect of vehicle modeling, Fuzzy controller is designed to explore BSS feasibility, by modifying the brake distribution through the control of the yaw rate of the vehicle. The control strategies developed will be tested by simulation of a variety of situation; the possibility of VDC using BSS is verified in this paper.

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Two pHZ1358 Derivative Vectors for Efficient Gene Knockout in Streptomyces

  • He, Yunlong;Wang, Zhijun;Bai, Linquan;Liang, Jingdan;Zhou, Xiufen;Deng, Zixin
    • Journal of Microbiology and Biotechnology
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    • v.20 no.4
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    • pp.678-682
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    • 2010
  • The deletion of sti from the Streptomyces plasmid pIJ101 made its derivative pHZ1358 an efficient vector for gene disruption and replacement. Here, pHZ1358 was further optimized by the construction of a derivative plasmid pJTU1278, in which a cassette carrying multiple cloning sites and a lacZ selection marker were introduced for convenient plasmid construction in E. coli. In addition, the oriT region of pJTU1278 was also deleted, generating a vector (pJTU1289) that can be used specifically for PCR-targeting. The efficient usage of these vectors was demonstrated by the deletion of the gene involved in avermectin biosynthesis in S. avermitilis.

A Study on Performance of Speech Recognition & Acoustic Parameter in Car Environment (자동차 주행 환경에서의 음성 인식 성능 및 음향 특성의 검토)

  • Lee Kwang-Hyun;Choi Dae-Lim;Kim Young-Il;Kim Bong-Wan;Lee Yong-Ju
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.269-272
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    • 2004
  • 주행 상태에서의 자동차 내부 음 환경은 다양한 소음 및 구조적 요인으로 인하여 음성에 대한 정상적인 전송 특성을 갖기 어렵다. 이는 음원으로부터 음성 입력 장치(Microphone)에 이르기까지의 채널 왜곡에 기인한 문제로써, 실제 주행 환경에서의 음성 인식 성능에 대해서도 심각한 악영향을 초래한다. 본 논문에서는 주행 소음의 크기에 따른 채널별 음성 왜곡 정도에 따른 명료도를 음성 전달 지수인 STI(Speech Transmission Index)를 통하여 분석하고 그 결과를 음성 인식률과 상호 비교하였다. 그리고 수음 패턴에 따른 명료도 척도와 음성 인식 성능과의 상관성을 검토하고, 이를 통해 단일 채널 환경에서 최적의 마이크로폰 위치에 대하여 고찰해 보았다. 실험 결과, 주행 중의 소음 환경에서도 음성의 명료도 척도와 인식률과의 관계는 높은 상관성이 얻어짐을 알 수 있었고, 각 채널 간의 성능 편차 패턴도 주행 환경에 따라 비슷한 양상을 보이는 것으로 나타났다.

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A Comparative Study of Web Information Resources on Science & Technology (과학기술분야 웹 정보원 평가 및 비교 연구)

  • 김석영
    • Journal of Korean Library and Information Science Society
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    • v.33 no.3
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    • pp.133-152
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    • 2002
  • The purpose of this study is to propose the criteria for evaluating web information resources. This study also attempts to get a sense of the overall quality of web information resources and to identify the relationship among the criteria, Particularly those on the science and technology. Three evaluation categories are Proposed; information content functionality or workability, and design. Core features of information content includes authority, relevancy, currency; functionality includes navigation, user support technical requirements; layout and design includes visual appearance. Based on the proposed criteria, the 50 sample web resources selected from 5 different field were evaluated. The results showed that the web information resources on the Electrical and Electronic Engineering field was excellent. The Pearson's correlation coefficient between evaluation criteria showed that information content and functionality had a negative relationship, on the other hand functionality and design had a moderate correlation.

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Identification of Differentially Expressed Proteins in Imatinib Mesylate-resistant Chronic Myelogenous Cells

  • Park, Jung-Eun;Kim, Sang-Mi;Oh, Jong-K.;Kim, Jin-Y.;Yoon, Sung-Soo;Lee, Dong-Soon;Kim, Young-Soo
    • BMB Reports
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    • v.38 no.6
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    • pp.725-738
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    • 2005
  • Resistance to imatinib mesylate (also known as Gleevec, Glivec, and STI571) often becomes a barrier to the treatment of chronic myelogenous leukemia (CML). In order to identify markers of the action of imatinib mesylate, we used a mass spectrometry approach to compare protein expression profiles in human leukemia cells (K562) and in imatinib mesylate-resistant human leukemia cells (K562-R) in the presence and absence of imatinib mesylate. We identified 118 differentially regulated proteins in these two leukemia cell-lines, with and without a $1\;{\mu}M$ imatinib mesylate challenge. Nine proteins of unknown function were discovered. This is the first comprehensive report regarding differential protein expression in imatinib mesylate-treated CML cells.

Active Handling Control of the Differential Brake System Using Fuzzy Controller (퍼지제어기를 이용한 차동브레이크 시스템의 능동 조향제어)

  • 윤여흥;장봉춘;이성철
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.5
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    • pp.82-91
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    • 2003
  • Vehicle dynamics control (VDC) has been a breakthrough and become a new terminology for the safety of a driver and improvement of vehicle handling. This paper examines the usefulness of a brake steer system (BSS), which uses differential brake forces for steering intervention in the context of VDC, In order to help the car to turn, a yaw moment can be achieved by altering the left/right and front/rear brake distribution. The steering function achieved through BSS can then be used to control lateral position in an unintended road departure system. An 8-DOF non-linear vehicle model including STI tire model will be validated using the equations of motion of the vehicle, and the non-linear vehicle dynamics. Since fuzzy logic can consider the nonlinear effect of vehicle modeling, fuzzy controller is designed to explore BSS feasibility, by modifying the brake distribution through the control of the yaw rate of the vehicle. The control strategies developed will be tested by simulation of a variety of situation; the possibility of VDC using BSS is verified in this paper.

A Trend Study on Collection Development Policy for Science and Technology Information Resources (과학기술정보 장서개발정책에 관한 동향연구)

  • Lee, Seon-Hee;Choi, Hee-Yoon
    • The Journal of the Korea Contents Association
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    • v.9 no.5
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    • pp.337-345
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    • 2009
  • World leading national science technology information institutes provide scientists with R&D information for increasing national competitiveness. Collection development policy is the guidelines for the science technology information institutes that identify information resources and connect them together to build an information network for supporting R&D. In order to draw main elements of the collection development policy for national level science and technology information institutes, this paper analyzed the policies of National Library of Medicine (NLM), British Library (BL), Canada Institute for Scientific and Technological Information (CISTI), and Korea Institute of Science and Technology Information(KISTI). The results of this study can be used as the guidelines for the science and technology information institutes for establishing collection development policy.

The Rise of Korean Innovation Policy for Social Problem-Solving: A Policy Niche for Transition?

  • Seong, Jieun;Song, Wichin;Lim, Hongtak
    • STI Policy Review
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    • v.7 no.1
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    • pp.1-16
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    • 2016
  • Technology supply has been the main thrust of the Korean government's science & technology policy, focusing on the development and acquisition of new technology in line with the catching-up strategy of economic growth and industrial development. However, new social or societal problems have become major government policy issues, heralding new innovation policy aimed to address them. Such new policy initiatives for social problem-solving present a niche where the existing system of government innovation policy process is challenged, including such processes as goal-setting, planning, implementation, project management, and evaluation. The rigidity of the existing institution of government innovation policy, however, still shapes the content and progression of innovation policy for social problem-solving. This study reviews Korean innovation policy for social problem-solving as a policy niche, and aims to clarify its challenges and opportunities. It uses a system transition framework to explain the emergence and evolution of the innovation policy niche in Korea. The main research question is to what extent and in what aspect the existing innovation policy regime shaped innovation policy for social problem-solving. The study examines the inertia of the current paradigm of innovation policies and R&D programs, and sheds light on the search for a distinctive identity for innovation policies that tackles social problems.