• 제목/요약/키워드: experimentals

검색결과 30건 처리시간 0.03초

댐 시설물 수중구조체 보수용 패칭재료의 적용 가능성 평가 (Evaluation of Underwater Dam Concrete Structure Repair by Patching Material)

  • 김완영
    • 한국농공학회논문집
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    • 제51권6호
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    • pp.77-81
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    • 2009
  • This study was performed to evaluate applicability of patching materials for underwater dam concrete structure. Two kinds of patching materials was investigated. Laboratory experimentals were conducted by workability, compressive strength, bond strength, chloride ion penetration, abrasion resistance. Test results showed that the most performances are relatively good except chloride ion penetration.

Fuzzy SOC를 이용한 하이드로 포밍 고정의 압력제어기 설계 (A fuzzy SOC based pressure tracking controller design for hydroforming process)

  • 김문종;박희재;조형석
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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    • pp.350-355
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    • 1990
  • A pressure tracking of hydroforming process is considered in this paper. To account for nonlinearities and uncertainty of the process. A fuzzy SOC based iterative learning control algorithm is proposed. A series of experimentals were performed for the pressure tracking control of the process. The experimental results show that regardless of inherent nonlinearties and uncertainties associated with hydraulic system. A good pressure tracking control performance is obtained using the proposed fuzzy learning control algorithm.

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Simulation and Experimentals of a Bi-Directional Converter with Input PFC on SRM System

  • Maged Maged N.F.
    • Journal of Power Electronics
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    • 제6권2호
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    • pp.121-130
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    • 2006
  • This paper presents the performance and efficiency of a drive system incorporating a switched-reluctance motor (SRM) with input power factor correction (PFC). The proposed system consists of a PFC, bi-directional converter, an inverter, and a SRM operating as based voltage source drives (VSD). First, theoretical analysis is made for each identified mode of operation in the drive system. This is followed by comparing the performance of the SRM drive system with and without a PFC circuit. The losses are also calculated for both systems and overall efficiency. Experimental results are presented to prove the theoretical analysis.

A Study on the Abnormal Behavior of the Viscosity near the Critical Point

  • Kim, Won-Soo;Pak, Hyung-Suk;Chair, Tong-Seek
    • Bulletin of the Korean Chemical Society
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    • 제10권4호
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    • pp.372-374
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    • 1989
  • The new viscosity theory is applied to the abnormal behavior of the viscosity near the critical point. This theory suggests that the viscosity is equal to the product of the absolute pressure(kinetic pressure + internal pressure) and the collision time. We can find this abnormal behavior to be due to the large collision time near the critical point. The agreements between theoriticals and experimentals of the critical enhancement are satisfactory.

두개하악장애와 두부전방자세와의 관계 (Relationship between Forward Head Posture and Craniomandibular Disorders)

  • Kyung-Soo Han
    • Journal of Oral Medicine and Pain
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    • 제19권1호
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    • pp.137-149
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    • 1994
  • This study was performed to investigate the relationship between Forward Head Posture(FHP) and Craniomandlbular Disorders(CMDs). Many studies reported that there was some relationship between them, however, there is still controversy. So It Is necessary to observe and compare many more patients with CMDs wirh normal controls. For the study 85 patients with CMDs and 37 dental students were selected as experimentals and controls, respectively. And the experimentals were classified Into two groups, that is, TMJ internal derangement group and muscle disorders group according to clinical diagnosis. For measuring the FHP, CROM(Cervical-Range-of-Notion)was used. This goniometer is composed of three part. First, gravity goniometer for flexion and extension. Second, magnetic compass and yoke for rotational movement. And last, forward head arm and vertebra locator for forward head posture. Next T-Scan, electronic occlusal analyzer, was used for recording of occlusal contact state. Other items such as maximum opening, lateral excursion, Helkimo's anamnestic index, and muscle palpation point from Friction's craniomandibular index were checked clinically by one examiner. The result of this study were as follows : 1. In male, control group showed much more measurement in resting forward head posture than did experimental group. But there were not significant differences between groups in female subject. From this results, the author contended that CROM is new measuring system and differ from other goniometers in some aspect, so that results should be re-evaluated 2. Mean value of maximum mouth opening in nearly all groups were greater than 40mm. and mouth opening had a significant correlation with occlusal force and with anamnestic index both sex. 3. Mean value of palpation point had not any correlationship with forward head posture in both sex, but there was significant difference between upper and lower group by rounded shouldes. 4. In summary, there was no significant relationship between forward head posture and sign and symptom of Craniomandibular Disorders.

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확률분포를 이용한 복합재료의 강도예측 (Prediction of Laminate Composite Strength Using Probabilistic Approach)

  • 조영준;강태진;이경우
    • Composites Research
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    • 제13권1호
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    • pp.33-39
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    • 2000
  • 복합재료 적층판의 최종강도를 점증적 파손 해석방법을 사용하여 예측하였다. 플라이 강도를 확률분포로 가정했을 경우와 상수로 가정했을 경우 각각의 최종강도를 예측하였다. 복합재료의 강도에 대한 확률분포인 Weibull 분포를 이용하여 임의의 강도 값을 얻은 후 이 값을 Tsai-Hill 파손식에 대입하여 파손여부를 판정하고 파손이 일어나면 재료의 물성을 떨어뜨렸다. 이 방법에 의해서 얻어진 결과를 플라이의 강도를 상수로 가정하여 해석한 경우와의 차이에 대하여 고찰하였다. 결과적으로 두 경우 모두 실험치와 약간의 오차를 보였지만 파손의 경향성에 있어서는 확률분포를 이용한 강도해석이 실험값과 더 근사한 결과를 보였다.

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Experimental Investigations on Barrier Oxidation in $N_{B}/A_{L}O_{X}/N_{B}$ Josephson Junctions

  • Kim, Kyu-Tae;Hong, Hyun-Kwon;Lee, Sang-Hwa;Nam, Du-Woo;Lee, Kyu-Won
    • 한국초전도ㆍ저온공학회논문지
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    • 제5권1호
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    • pp.17-20
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    • 2003
  • Josephson junctions were fabricated for several oxidation conditions and several junction sizes. Considering self-field effect suppressing the observed critical current (Ic) at large junctions, the observed Ic values were in good agreement with theoretical prediction. The predicted junction critical current for small junction limit was also confirmed by experiment. The dependence of the estimated Jc as a function of oxidation exposure showed that our junctions have lower Jc than other authors' at the same oxidation exposure. This is thought to be one of equipment-specific phenomena. Details of experimentals will be reported with brief discussion.

Wire-Plate 반응기에서 펄스 코로나 방전을 이용한 탈황 탈질에 관한 연구 (A Study on the Removal of SOx/NOx by a Pulsed Corona Discharge in the Wire-Plate Reactor)

  • 신완호;송영훈;김한석;최연석;김석준
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1996년도 하계학술대회 논문집 C
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    • pp.1910-1912
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    • 1996
  • This paper presents the results of laboratory experimentals to remove $SO_2$ and $NO_x$ by a pulsed corona discharge in the wire-plate reactor. A rotating spark gap switch was used to generate the pulse by chewing the dc high voltage. Repetition frequency of the pulse was 60Hz and rising time of 50ns. The photo pictures of positive streamer corona taken by ICCD camera, pulse voltage and current were measured using a digital oscilloscope. Simultaneous effects of $C_{2}H_{4}$ injection and heterogeneous chemical reactions on nonthermal plasma process to remove $SO_2$ and $NO_x$ from flue gas were investigated in the present study

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Poly(methyl acrylate)-Poly(acrylonitrile) 공중합체의 응력완화 (Stress Relaxation of Poly(methyl acrylate)-Poly(acrylonitrile) Copolymers)

  • 김남정
    • Elastomers and Composites
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    • 제47권3호
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    • pp.223-230
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    • 2012
  • 응력완화 실험 곡선을 Eyring-Halsey 비뉴톤 모델의 이론식에 적용하여 poly(methyl acrylate)-poly(acrylonitrile) 공중합체의 유변학적 파라메타를 얻었다. 응력완화 실험은 용매기를 부착한 인장 시험기를 사용하였다. 유동 파라메타를 컴퓨터 프로그램을 이용하여 계산하였다. 이들 시료의 유동 파라메타는 유동 단위의 자체확산, 유동점성, 유동 활성화 에너지와 직접적인 연관을 갖는 것으로 규명되었다.