• 제목/요약/키워드: Stiffness improvement

검색결과 423건 처리시간 0.028초

급성 경추 경막외 농양 및 경추척추염과 동반된 결핵성 수막염 1예 (A Case of Tuberculous Meningitis Combined with Acute Cervical Epidural Abscess and Cervical Spondylitis)

  • 이동국
    • Annals of Clinical Neurophysiology
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    • 제4권2호
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    • pp.140-145
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    • 2002
  • Neurologic sequelae of tuberculous meningitis include hemiparesis, paraparesis, quadriparesis, aphasia, developmental delay, dementia, blindness, visual field defect, deafness, cranial nerve palsies, epilepsy, and hypothalamic and pituitary dysfunction. But cervical epidural abscess and cervical spondylitis are rare. A 64-year-old woman who was diagnosed as tuberculous meningitis presented a severe neck pain and stiffness after 3 weeks of anti-tuberculous medication. Electromyography and cervical X-ray showed a cervical spondylosis with polyradiculopathy. But cervical MRI showed an acute cervical epidural abscess and mild cervical spondylitis. After continuous anti-tuberculous medication with supportive care, she showed a slow clinical improvement. But about 1 month of anti-tuberculous therapy, she presented a more aggravation of neck pain, neck stiffness, radicular pain, and neck motion limitation. Follow-up cervical MRI showed an more advanced cervical spondylitis. Afterthen she has recovered slowly by cervical laminectomy with posterior stabilization and continuous anti-tuberculous medication.

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엠보싱 구조재의 성형성 향상에 관한 연구 (A Study on the Improvement of Formability of Embossing Structure)

  • 김형종;정동원;최두선;제태진;박재현
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.1269-1272
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    • 2005
  • Sandwich structures, which are composed of thick core between two thin faces, are commonly used in many engineering applications because they combine high stiffness and strength with low weight. In this research, we have investigated the embossing configuration at the sheet metal shape through research with regard to the construction that the hardness and stiffness are excellent, and formability is advantage as inner structure. Through the FLD analysis according to the pattern changes, we have confirmed the forming possibility and variation of the aspect thickness. Also, we have fabricated the embossing press mold according to the pattern changes, and obtained the embossing inner structure the forming experiments.

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능동 복합 베어링 개발 (A Study on the Development of Active Hybrid Bearing)

  • 박정훈;심풍수;박철학;이태영
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.269-275
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    • 2005
  • This article describes the development on a new style active hybrid bearing system including both merits of an aerostatic bearing system and a magnetic bearing system. The developed active hybrid bearing system has several advantages: exact rotation, robust controller against the variation of a disturbance, improvement of stiffness and a damper of the system at a high-speed operation, and constraints of the heat generated by a bias current. In order to measure a rotating error due to the change of a cutting force and the variation of a system parameter, a CCS (Cylindrical Capacity displacement Sensor) was used.

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$TiO_2$/PEG처리 면직물의 물성과 자외선 차단성능 (Properties and UV-cut effects of cotton fabric treated with $TiO_2$/PEG)

  • 김정진;장정대
    • 한국염색가공학회지
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    • 제14권4호
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    • pp.223-228
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    • 2002
  • Cotton fabric was treated with $TiO_2$-PEG600 dispersion colloid by pad-dry-cure and wet-fixation process to improve the performance properties as well as UV-cut effect. As the concentration of $TiO_2$/PEG increased tensile strength, crease resistance, stiffness of treated cotton fabric increased. Application of wet-fixation method provided a further improvement in tensile strength, crease resistance, stiffness of treated cotton fabric. Cotton fabric treated with $TiO_2$/PEG was more efficient in UV-cut property than untreated cotton.

굽힘곡선을 이용한 공작기계 주축의 정적 동적 취약부 규명 (Static and Dynamic Weak Point Analysis of Spindle Systems Using Bending Curve)

  • 이찬홍;이후상
    • 한국정밀공학회지
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    • 제15권12호
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    • pp.188-193
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    • 1998
  • This paper describes static and dynamic weak point analysis of spindle systems to eliminate high concentrated bending point on spindle and improve total stiffness of spindle systems. The weak point analysis is based on the evaluation of bending curves of spindles. For static weak point analysis the bending curve is derived from static deflection curve and for dynamic weak point analysis it is derived from the mode shape curves in consideration of the transfer function at exciting point. The validity of the weak point search methodology is verified by comparison of the static deflection, the natural frequency and the dynamic compliance between the original and the improved spindle.

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Spindle Design Technology for High Speed Machine Tools

  • Lee, Chan-Hong
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 Handout for 2000 Inter. Machine Tool Technical Seminar
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    • pp.109-115
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    • 2000
  • The spindle unit is core parts in high precision machine tools. Diverse static, dynamic and thermal charateristics of spindle unit are needed for special purpose of machine tools. Compromise between those charateristics will be done in concept design phase. High static stiffness at spindle nose may be very important performance for heavy cutting work. High dynamic stiffness is also useful to high precision and high speed machine tools. Improvement of thermal charateristics in spindle lead to high reliability of positioning accuracy. For high speed spindle structure, the design parameter such as, bearing span, diameter, bearing type and arrangement, preload, cooling and lubrication method should be in harmony.

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탄성채널을 이용한 석고보드 건식벽체의 저주파 대역 차음성능 개선 (Improvement of Sound Insulation at Low Frequencies Using Resilient Channel)

  • 김경호;전진용
    • 한국소음진동공학회논문집
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    • 제27권1호
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    • pp.94-99
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    • 2017
  • Breaking the rigid connection between the two faces of the wall can significantly improve the sound transmission loss of the wall. This is usually achieved by resiliently mounting the gypsum board on one of the two faces of the wall using resilient channel. Resilient channel with less stiffness than that of air cavity could move the resonance frequency of the light-weight wall. So we can get higher sound transmission loss at low frequencies for light-weight wall using resilient channel. It's sound transmission loss is 17 dB higher than that of single stud wall, and 5 dB higher than that of double stud wall.

류마치양 관절염 및 퇴행성관절염에 대한 Piroxicam의 사용경험 (Clinical Report for Piroxicam in Orthopedic Field)

  • 윤승호;이광진;안상노
    • 대한약리학회지
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    • 제15권1_2호
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    • pp.39-43
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    • 1979
  • Piroxicam is known to be a new nonsteroidal anti-inflammatory drug which has anti-inflammatory, antiedema, antigranuloma and analgesic activities through the mechanism of inhibition of prostaglandin synthetase. Clinical survey for piroxicam was carried cut on 40 cases of rheumatoid arthritis and 30 cases of degenerative arthritis who visited University Hospital from Feb. to June, 1979. Following results could be obtained: 1) In rheumatoid and degenerative arthritis, the effect of piroxicam was significant in decrease of joint pain, shortening of duration of morning stiffness, decrease in number of swollen joints, improvement of joint stiffness, decrease of E.S.R., increase of mean grip strength and decrease of articular index. 2) Side effects, almost all in G-I troubles were encountered in 6 cases in 40 cases of rheumatoid arthritis and 4 cases in 30 cases of degenerative arthritis.

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RCC frames with ferrocement and fiber reinforced concrete infill panels under reverse cyclic loading

  • Ganesan, N.;Indira, P.V.;Irshad, P.
    • Advances in concrete construction
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    • 제5권3호
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    • pp.257-270
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    • 2017
  • An experimental investigation was carried out to study the strength and behavior of reinforced cement concrete (RCC) frames with ferrocement and fiber reinforced concrete infill panel. Seven numbers of $1/4^{th}$ scaled down model of one bay-three storey frames were tested under reverse cyclic loading. Ferrocement infilled frames and fiber reinforced concrete infilled frames with varying volume fraction of reinforcement in infill panels viz; 0.20%, 0.30%, and 0.40% were tested and compared with the bare frame. The experimental results indicate that the strength, stiffness and energy dissipation capacity of infilled frames were considerably improved when compared with the bare frame. In the case of infilled frames with equal volume fraction of reinforcement in infill panels, the strength and stiffness of frames with fiber reinforced concrete infill panels were slightly higher than those with ferrocement infill panels. Increase in volume fraction of reinforcement in the infill panels exhibited only marginal improvement in the strength and behavior of the infilled frames.

Force control of robot manipulator using fuzzy concept

  • Sim, Kwee-Bo;Xu, Jian-Xin;Hashimoto, Hideki;Harashima, Fumio
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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    • pp.907-912
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    • 1990
  • An approach to robot force control, which allows force manipulations to be realized without overshot and overdamping while in the presence of unknown environment, is given in this paper. The main idea is to use dynamic compensation for known robot parts and fuzzy compensation for unknown environment so as to improve system performance. The fuzzy compensation is implemented by using rule based fuzzy approach to identify unknown environment. The establishment of proposed control system consists of following two stages. First, similar to the resolved acceleration control method, dynamic compensation and PID control based on known robot dynamics, kinematics and estimated environment compliance is introduced. To avoid overshoot the whole control system is constructed overdamped. In the second stage, the unknown environment stiffness is estimated by using fuzzy reasoning, where the fuzzy estimation rules are obtained priori as the expression of the relationship between environment stiffness and system response. Based on simulation result, comparisons between cases with or without fuzzy identifications are given, which illustrate the improvement achieved.

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