• 제목/요약/키워드: measurement of arc

검색결과 279건 처리시간 0.028초

실시간 용접변형 계측을 위한 시스템에 관한 연구 (A Study on System for Real-time Measurement of Welding Distortion)

  • 정재원;김일수;김인주;손성우;심지연
    • Journal of Welding and Joining
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    • 제27권5호
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    • pp.62-67
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    • 2009
  • Welding deformation during the assembly process is affected by not only local shrinkage due to rapid heating and cooling, but also root gap and misalignment between parts to be welded. Therefore, the prediction and control of welding deformation have become of critical importance. In this study, it was focused on the development of the 3-axis apparatus for real-time measurement of the welded deformation. To achieve the objective, a D-H algorithm has been carried out to check the behavioral and performance evaluation for the developed robot. The sequence experiments were taken the base materials of $400{\times}200{\times}4.5mm$ plate for butt welding. The real-time experimental measurements are in good agreement with the measured results.

EVALUATION OF THE MEASUREMENT NOISE AND THE SYSTEMATIC ERRORS FOR THE KOMPSAT-1 GPS NAVIGATION SOLUTIONS

  • Kim Hae-Dong;Kim Eun-Kyou;Choi Hae-Jin
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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    • pp.278-280
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    • 2004
  • GPS Navigation Solutions are used for operational orbit determination for the KOMPSAT-1 spacecraft. GPS point position data are definitely affected by systematic errors as well as noise. Indeed, the systematic error effects tend to be longer term since the GPS spacecrafts have periods of 12 hours. And then, the overlap method of determining orbit accuracy is always optimistic because of the presence of systematic errors with longer term effects. In this paper, we investigated the measurement noise and the system error for the KOMPSAT-l GPS Navigation Solutions. To assess orbit accuracy with this type of data, we use longer data arcs such as 5-7 days instead of 30 hour data arc. For this assessment, we should require much more attention to drag and solar radiation drag parameters or even general acceleration parameters in order to assess orbit accuracy with longer data arcs. Thus, the effects of the consideration of the drag, solar radiation drag, and general acceleration parameters were also investigated.

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충격파-부분방전(SI-PD) 시험방법을 이용한 케이블 진단에 관한 기초 연구 (A Possible diagnostic method of cable system using SI-PD measurement)

  • 김정태;구자윤;장은;조연옥;김상준;송일근;김주용
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1996년도 하계학술대회 논문집 C
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    • pp.1774-1777
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    • 1996
  • In this paper, applicability of SI-PD(switching impulse - partial discharge) testing method was put on an attempt as a newly proposed diagnostic method for the underground distribution power cable system in Korea. For this purpose, SI-PD testing equipment was designed, and tests were performed using artificial needle-type defects integrated into the 22.9 kV CN/CV cables in drder to prove its reliability. As a result, arc noises, generated from spark gap, were considerably decreased by use of a pneumatic switch immersed into oil, and artificial needle-type defects were well detected with impulse voltage level under $2U_0$. These results imply that it is likely possible to apply SI-PD measurement method as a the nondistructive test for the 22.9 kV CN/CV cable system in Korea.

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컴퓨터에 의한 한복 여자 두루마기 원형제도에 관한 연구 (A Study of Pattern Making of Dooroomaky by Computer)

  • 김희숙
    • 한국의류학회지
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    • 제12권3호
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    • pp.319-331
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    • 1988
  • The purpose of this study was to develop a computer program for pattern making of women's Dooroomaky. The following results were given through utilizing the Computer in pattern making of Dooroomaky for women. 1. Computerization of the pattern making process was expected to provide higher accuracy and efficiency in pattern making. 2. Basic pattern was drafted by the hand-operation. In this study, this Dooroomaky basic pattern was selected. And a computer program for drafting was developed. Refer to

    1. 3. Basic points which can be connected to depict basic pattern are represented with the numerical expression and the curved lines consist of the types of Arc Command. 4. In order to draft straight lines of the basic pattern, relative co-ordinate values of all standard points were prescrived and each two standard points were connected in straight lines respectively. 5. The patterns of Dooroomaky were automatically depicted by inputting the standard size (large, medium and small) find body measurement for pattern(bust girth, center back length, sleeve length, Dooroomaky length). 6. Grading of standard size was accomplished by using same method.

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  • Hardness prediction based on microstructure evolution and residual stress evaluation during high tensile thick plate butt welding

    • Zhou, Hong;Zhang, Qingya;Yi, Bin;Wang, Jiangchao
      • International Journal of Naval Architecture and Ocean Engineering
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      • 제12권1호
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      • pp.146-156
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      • 2020
    • Two High Tensile Strength Steel (EH47) plates with thickness of 70 mm were butt-welded together by multi-pass Submerged Arc Welding (SAW), also the hardness and welding residual stress were investigated experimentally. Based on Thermal-Elastic-Plastic Finite Element (TEP FE) computation, the thermal cycles during entire welding process were obtained, and the HAZ hardness of multi-pass butt welded joint was computed by the hardenability algorithm with considering microstructure evolution. Good agreement of HAZ hardness between the measurement and computational result is observed. The evolution of each phase was drawn to clarify the influence mechanism of thermal cycle on HAZ hardness. Welding residual stress was predicted with considering mechanical response, which was dominantly determined by last cap welds through analyzing its formation process.

    Separation of Isochromatics and Isoclinics from Photoelastic Fringes in a Circular Disk by Phase Measuring Technique

    • Baek, Tae-Hyun;Kim, Myung-Soo;Yoshihau Morimoto;Motoharu Fujigaki
      • Journal of Mechanical Science and Technology
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      • 제16권2호
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      • pp.175-181
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      • 2002
    • A new polariscope system involving two rotating optical elements and a digital camera for whole field fringe analysis allows automated data to be acquired quickly and efficiently. The developed phase measuring technique that uses eight images through a circular polariscope is presented for the digital measurement of isochromatics and isoclinics, respectively, from photoelastic fringes in a circular disk under diametric compression. Isochromatics can directly be obtained using wrapped isoclinic phases calculated by the arc tangent operator which is the four-quadrant operator from -$\pi$ to $\pi$. It is not required to unwrap isoclinic phases for the calculations of isochromatics. Unwrapped isoclinics are directly determined from isochromatic parameters. Distributions of digitally determined isoclinics are in close agreement to manual measurements. The errors which would appear in unwrapping process of isoclinics can be avoided in the determination of isochromatics.

    정전기 방전시의 분체류의 최소착화에너지 측정에 관한 연구 (A Study of Minimum Ignition Energy Measurement of Explosive Powders Caused by Electrostatic Discharges)

    • 이동훈;목연수;최재욱;신중현;류상민;조일건;정준채
      • 한국산업안전학회:학술대회논문집
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      • 한국안전학회 1997년도 춘계 학술논문발표회
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      • pp.67-75
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      • 1997
    • To establish testing method for ignition energy of explosive powders caused by electrostatic discharge, one testing method using a very small quantity of tested powders ( Frima ) was proposed, and the influence of discharge - limiting resistance connected in series into a capacitive discharge circuit on ignition energies of explosive powders was investigated using, as tested powders. As a result the minimum ignition energy was 9 mJ when discharge-limiting resistance was 300 k$\Omega$. The reason for the dependence of ignition energy on discharge-limiting resistance was thought to the difference in the type of electrostatic discharge, such as arc or glow discharge, from the observation of discharging wave forms.

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    Wire Feeding Speed Control for Improving Welding Performances in Inverter Arc Welding Machine

    • Gho, J.S.;Chae, Y.M.;Chae, J.W.;Mok, H.S.;Choe, G.H.;Shin, W.S.
      • 전력전자학회:학술대회논문집
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      • 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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      • pp.464-469
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      • 1998
    • In the conventional wire feeder drives of welding machine, one thyristor or MOSFET device was used for half-wave phase control circuit and direct EMF measurement was used for sensing the wire feed rate. But the method using one switching device has poor response for sudden disturbance and it has latent speed ripple. It can affect some welding performance such as spatter generation and irregular bead formming. Therefore, the welding performance using full-bridge PWM speed control scheme was compared with conventional driving scheme was compared with conventional driving scheme and experimented in this paper. The results of experiment confirm the posibility of welding performance improvement by proposed constant speed control scheme in wire feeding drive of welding machine.

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    Sliding Wear and Corrosion Resistance of Copper-based Overhead Catenary for Traction Systems

    • Kwok, C.T.;Wong, P.K.;Man, H.C.;Cheng, F.T.
      • International Journal of Railway
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      • 제3권1호
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      • pp.19-27
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      • 2010
    • In the present study, the electrical sliding wear and corrosion resistance of pure copper (Cu) and six age-hardened copper alloys (CuCr, CuZr, CuCrZr, CuNiSiCr, CuBe and CuBeNi) were investigated by a pin-on-disc tribometer and electrochemical measurement. Various copper-based alloys in the form of cylindrical pin were forced to slide against a counterface stainless steel disc in air under unlubricated condition at a sliding velocity of 31 km/h under normal load up to 20 N with and without electric current. The worn surface of and wear debris from the specimens were studied by scanning electron microscopy. Both mechanical wear and electrical arc erosion were the wear mechanisms for the alloys worn at 50 A. Owing to its good electrical conductivity, high wear and corrosion resistance, CuCrZr is a promising candidate as the overhead catenary material for electric traction systems.

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    분광 분석법에 의한 고압 수은등의 온도분포 측정 (Temperature Distribution Measurement of High-pressure Mercury Lamp using Spectroscopic Method)

    • 김상용;김창섭;지철근
      • 한국조명전기설비학회:학술대회논문집
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      • 한국조명전기설비학회 1989년도 추계학술발표회논문집
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      • pp.13-18
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      • 1989
    • Temperature distribution of 250W high-pressure mercury lamp has been measured by the spectroscopic method using relative intensities of spectral lines. To obtain radial temperature distribution, the measured intensity which was integrated along the line of sight was transformed into radial line intensity by Abel's inversion. Temperature was determined from relative intensities of spectral lines of the same atomic species. The measured temperature of 250W high-pressure mercury lamp is 6000K at the axis. In this experiment temperature profile of high-pressure arc is papabolic as known.

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