• 제목/요약/키워드: Mechanisms

검색결과 13,070건 처리시간 0.037초

외상성 신경병증 환자의 치험례 (A CASE REPORT OF TRAUMATIC NEUROPATHIC PAIN PATIENT)

  • 최문기
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제34권2호
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    • pp.200-206
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    • 2008
  • A variety of mechanisms may generate pain resulting from injury to the peripheral nervous system. None of these mechanisms is disease-specific, and several different pain mechanisms may be present simultaneously in any one patient. Diagnosis of neuropathic pain is often easily made from the information gathered on neurologic examination and from patient history. Evidence of sensory disturbances elicited by examination combined with laboratory tests confirming injury to peripheral nerve establishes the diagnosis of neuropathic pain. Although treatment of neuropathic pain may be difficult, optimum treatment can be achieved if dentist has a complete understanding of the therapeutic options. Pharmacologic therapy has been the mainstay of treatment. Selection of an appropriate pharmacologic agent is by trial and error since individual response to different agents, doses, and serum level are highly variable. An adequate trial for each agent tried is key to pharmacologic treatment of neuripathic pain. If pharmacologic treatment is not effective, nerve block using lidocaine, steroid and alcohol and neurectomy must be considered for treatment option.

CAE를 이용한 VTR Deck기구의 해석 및 설계 (A study on the analysis and design for VTR deck mechanisms using CAE)

  • 박태원;범진환;한형석;김명규;김광배
    • 대한기계학회논문집
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    • 제17권1호
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    • pp.223-235
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    • 1993
  • 본 연구에서는 첫째로 병진 캠 전용해석 및 설계 프로그램을 개발하였다. 이 개발된 프로그램들을 기구해석전용 프로그램에 접속시켜 VTR Deck에 대한 전반적인 해석 및 설계가 가능하도록 하였다.

원호접근법을 이용한 디스크 캠기구의 운동해석에 관한 연구 (A Study on the Motion Analysis for Disk Cam Mechanism Using Circular Arc)

  • 구병국;신중호;윤호업;장옥화
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집A
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    • pp.772-777
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    • 2000
  • Cam mechanisms are used commonly in many automatic machinery. Disk cam mechanisms has 4 different types according to the different types of followers. The motion characteristics of the cam mechanisms depend on the shape of the cam and the type of the follower. This paper performs the motion analysis for a disk cam and follower mechanism using a circular arc method and a coordinate transformation method in order to find a contact point of the cam and follower. The velocity is calculated by using the instant velocity concept. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

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Reaction Mechanisms and Kinetics of Antioxidant Using Arrhenius Equation in Soybean Oil Oxdation

  • Cho, Hyung-Young
    • Preventive Nutrition and Food Science
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    • 제2권1호
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    • pp.6-10
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    • 1997
  • The reaction mechanisms and kinetics of tertiary butylhydroquinone(TBHQ) as an antioxidant in soybean oil oxidation were studied. The oxidation reaction of soybean oil at 55, 60 and $65^{\circ}C$ was a first order. The activation energies of soybean oil containing 0, 25, 50, and 75ppm TBHQ were 12.15, 6.05, 6.15 and 6.17kcal/mole. respectively. The addition of THQ to soybean oil containing 0, 25, 50, and 75ppm TBHQ were 1.88$\times${TEX}$10^{7}${/TEX}, 4.10$\times${TEX}$10^{2}${/TEX}, 4.32 $\times${TEX}$10^{2}$p/TEX} and 3.97$\times${TEX}$10^{2}${/TEX}, respectively. The decrease of frequency factor rather than the activation energy. The effects of antioxidants on the temperature dependecy of lipid oxidation could be effectively evaluated by measuring their effects on the activation energy of lipid oxidation.

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다자세 제어가 가능한 휠체어용 의자기구의 설계 및 제어 (Design and Control of Seat Mechanism for Multi-postures Controllable Wheelchair)

  • 배주환;김규석;류제청;문인혁
    • 한국정밀공학회지
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    • 제27권5호
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    • pp.102-111
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    • 2010
  • This paper presents a design of seat mechanism for multi-postures controllable wheelchair. The possible seat postures are reclining, tilting, standing, which are controlled by four seat mechanisms using four linear actuators. The seat mechanisms designed in this study are reclining, tilting, forward-tilting, and elevation mechanism. Three postures except standing are controlled by corresponding mechanisms, but the standing posture is performed by combination of the reclining and the forward-tilting mechanism. Posture control system is composed of PID controllers and a planner to determine a feasible posture based on a posture transition diagram. Simulation results show that the seat mechanism and its control system are applicable to a multi-postures controllable wheelchair.

평면형 3 자유도 병렬 메카니즘의 정밀도 특성에 관한 연구 (Study on the Precision Characteristics of a Planar 3 Degrees-of-Freedom Parallel Mechanism)

  • 김재섭;김희국;조황
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1996년도 추계학술대회 논문집
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    • pp.781-786
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    • 1996
  • In this paper, output precision characteristic of planar 3 and 6 degree-of-freedom parallel mechanisms are investigated. The 6 degree-of-freedom mechanism is formed by adding an additional small link along with an actuated joint in each of serial subchain of the 3 degree-of-freedom mechanism. First, kinematic analysis for two parallel mechanisms are performed, then their first-order kinematic characteristics are examined via isotropic index and minimum velocity transmission ratio of the mechanisms. It can be concluded that the planar 6 degrees-of-freedom parallel mechanism can be very effectively employed as a high-precision macro-micro manipulator from the analysis results when its link lengths are properly chosen.

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차동기어장치와 V-벨트식 변속기구를 결합한 무단변속기의 성능 (Performance of CVTs Composed of a Differential Gear Unit and a V-belt Drive)

  • 최상훈
    • 한국정밀공학회지
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    • 제20권2호
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    • pp.199-208
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    • 2003
  • Continuously variable transmission (CVT) mechanisms considered here combine the functions of a K-H-V type differential gear unit and a V-belt type continuously variable unit (CVU). As combining the functions of a K-H-V type differential gear unit and a V-belt type CVU, 24 different mechanisms are presented. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. These mechanisms have many advantages which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral.

유리-탄소 하이브리드 복합재료의 파괴인성에 관한 연구 (A Study on the Fracture Toughness of Glass-Carbon Hybrid Composites)

  • 노호섭;고성위
    • 수산해양기술연구
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    • 제28권3호
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    • pp.295-305
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    • 1992
  • The critical strain energy release rate and the failure mechanisms of glass-carbon epoxy resin hybrid composites are investigated in the temperature range of the ambient temperature to 8$0^{\circ}C$. The direction of laminates and the volume fraction are [(+45, -45, 0, 0) sub(2) ] sub(s), 50%, respectively. The major failure mechanisms of these composites are studied using the scanning electron microscope for the fracture surface. Results are summarized as follows: 1) The critical strain energy release rate shows a maximum at ambient temperature and it tends to decrease as temperature goes up. 2) The critical strain energy release rate increases as the content of glass increases, and especially shows dramatic increase for the high glass fiber content specimens. 3) Major failure mechanisms can be classfied such as localized shear yielding, fiber-matrix debonding, matrix micro-cracking, and fiber pull-out and/or delamination.

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Regulation of Nrf2-Mediated Phase II Detoxification and Anti-oxidant Genes

  • Keum, Young-Sam
    • Biomolecules & Therapeutics
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    • 제20권2호
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    • pp.144-151
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    • 2012
  • The molecular mechanisms by which a variety of naturally-occurring dietary compounds exert chemopreventive effects have been a subject of intense scientific investigations. Induction of phase II detoxification and anti-oxidant enzymes through activation of Nrf2/ARE-dependent gene is recognized as one of the major cellular defense mechanisms against oxidative or xenobiotic stresses and currently represents a critical chemopreventive mechanism of action. In the present review, the functional significance of Keap1/Nrf2 protein module in regulating ARE-dependent phase II detoxification and anti-oxidant gene expression is discussed. The biochemical mechanisms underlying the phosphorylation and expression of Keap1/Nrf2 proteins that are controlled by the intracellular signaling kinases and ubiquitin-mediated E3 ligase system as well as control of nucleocytoplasmic translocation of Nrf2 by its innate nuclear export signal (NES) are described.

A Guide for Analyzing Fault Causes of Pole Transformers

  • Jung, Jong-Wook;Lee, Byung-Sung;Song, Il-Keun;Kwak, Hee-Ro
    • KIEE International Transactions on Power Engineering
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    • 제2A권3호
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    • pp.114-120
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    • 2002
  • This paper describes the symptoms with the fault causes of pole transformers analyzed by Korea Electric Power Corporation(KEPCO) branch offices' request in 2001, and ultimately aims to devise proper countermeasures against the faults. The fault causes are generally divided into problems in manufacturing, mounting and operating. The pole transformers encounter the fault with unique aging mechanisms. To verify the mechanisms with the faults and to devise proper countermeasures, a flowchart for analyzing the fault causes is proposed, by which the fault causes of the pole transformers can be analyzed more exactly.