• 제목/요약/키워드: Radial velocity

검색결과 616건 처리시간 0.03초

Observation of the Bright Spectroscopic Binary Systems with DOAO/eShels Spectrograph

  • Shim, Hyunjin;Lee, Dongseob;Jeong, Yoonji;Kang, Wonseok;Kim, Taewoo
    • 천문학회보
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    • 제43권2호
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    • pp.51.1-51.1
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    • 2018
  • Based on the DOAO/eShels observations, we have derived radial velocity curves of the three Algol-type spectroscopic binary systems : Algol, ${\beta}$ Aur, and ${\varepsilon}$ Per. The radial velocity amplitudes of the primary and the secondary (K1 and K2) were consistent within a few % of the values from the previous studies. Mass ratios between the two stars that constitutes each system ranges ~1 to ~10. In addition to the orbital elements derived, we discuss about the spectroscopic ability of the DOAO/eShels instrument.

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SPECTROSCOPIC STUDY OF 31 CYGNI

  • Song, Hye-Kyeong;Chun, Mun-Suk
    • Journal of Astronomy and Space Sciences
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    • 제8권1호
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    • pp.25-51
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    • 1991
  • The spectra of 31 Cygni were taken at the Asiage Observatory in Italy. Reduction was made using the 2nd and 4th order non-linear least square method. Spectral lines which were relatively sharp or strong were identified within the wavelength regions from 3800 to 5100$AA$. Radial velocities and equivalent widths were calculated from the Gaussian Fitting Method for this star. The measured mean radial velocity of 31 Cygni is + 0.5km/sec.

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회전하는 타이어 내부공기의 유동특성에 관한 실험적 연구 -무부하 회전구동 타이어- (An Experimental Study on the Characteristics of Air Flow Velocity Distritutions Inside a Rolling Tire -Unloaded Rolling Tire-)

  • 김윤제;조정현
    • 한국자동차공학회논문집
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    • 제7권6호
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    • pp.174-181
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    • 1999
  • in order to elucidate the characteristic of velocity distribution of the cavity air. Exploratory tests were conducted on an unloaded rolling radial tire operated at various speeds and inflation pressure. A hot-wire anemometer, rotating with the tire, was used to measure the flow velocity inside the tire cavity. Tow different types of experiments were performed ; one for the effects of rolling speed with constant inflation pressure, the other for the various cavity pressures with constant rolling speed. Experimental results are given as plots of the mean velocity distributions versus the distance from the rim. It is observed that the magnitude of mean velocity in the cavity air shows increasing natures with the increasing of the inflation pressures and rolling speeds.

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상계해법에 의한 압출가공의 비틀림 해석 (An Upper Bound Analysis for the Twisting Phenomenon of Extrusion)

  • 김한봉;진인태
    • 소성∙가공
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    • 제7권4호
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    • pp.340-346
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    • 1998
  • A kinematically admissible velocity field is developed for the analysis of twisting of the extruded products with elliptical shapes from round billet. The twisting of extruded product is caused by the lin-early increased rotational velocity from the center on the cross-section of the workpiece at the die exit. In the analysis the rotational velocity in angular direction is assumed by the multiplication of radial distance and angular velocity. The angular velocity is zero at the die entrance. The increase rate of angular velocity is determined by the minimization of plastic work. The results of the analysis show that the angular velocity of the extruded product in creases with the die twisting angle, the aspect ratio of product the friction condition, the reduction of area, and decreases with the die length.

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상계해법에의한 원형빌렛으로부터 S형 단며의 압출가공의 비틀림 해석 (An Upper Bound Analysis for the Twisting Phenomenon of Extrusion of S shape from Round Billet)

  • 진인태
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1997년도 춘계학술대회논문집
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    • pp.130-135
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    • 1997
  • A kinematically admissible velocity field is developed for the analysis of twisting of extruded products. The twisting of extruded product is caused by the linearly increased rotational velocity from the center on the cross-section of the workpiece at the die exit. In the analysis, the rotational velocity in angular direction is assumed by the multiplication of radial distance and angular velocity. The angular velocity is zero at the die entrance and is increased linearly by longitudinal distance from die entrance. The increase rate of angular velocity is determined by the minimization of plastic work. The results of the analysis show that the angular velocity of the extruded product changes with the aspect ratio of product and increases with the decreases in die length and in eccentricity of gravity center of the cross-section of workpiece at die entrance from that of the cross-section at the die exit.

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고속도성(高速度星)의 역학적해석(力學的解釋)에 대(對)한 연구(硏究) (A Study on the Interpretation of the Dynamical Properties of the High Velocity Stars)

  • 이영범;유경노
    • 천문학회지
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    • 제4권1호
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    • pp.1-8
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    • 1971
  • The average velocity, 330km/sec. of the high velocity stars with respect to the galactic center is obtained from the data used by Fricke on the assumption that the rotational velocity of the Local Standard of Rest is 250km/sec. Comparing this value with the escape velocity, 380km/sec, at the solar neighborhood which is calculated from Mestel's model of the Galaxy, it is shown that most of the high velocity stars are bound to the Galaxy and that their average apogalacticon is about 40 kpc from the galactic center. And the fact that stars with radial velocities larger than 63km/sec are missing in the direction of galactic rotation of L.S.R. is interpreted as the result partly of the random distribution of the directions of motion of the high velocity stars and partly of the observational errors.

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SPECTROSCOPIC STUDY OF LONG PERIOD ECLIPSIING BINARY 32 CYGNI

  • Chun, Mun-Suk
    • Journal of Astronomy and Space Sciences
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    • 제9권2호
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    • pp.143-153
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    • 1992
  • Spectra of the $\zeta$ Aurigae type eclipsing binary system 32 Cygni were taken at the Asiago Observatory. Using the Gaussian fitting method we can estimate the radial velocity and equivalent widths of some metalic lines.

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Predicting strength development of RMSM using ultrasonic pulse velocity and artificial neural network

  • Sheen, Nain Y.;Huang, Jeng L.;Le, Hien D.
    • Computers and Concrete
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    • 제12권6호
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    • pp.785-802
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    • 2013
  • Ready-mixed soil material, known as a kind of controlled low-strength material, is a new way of soil cement combination. It can be used as backfill materials. In this paper, artificial neural network and nonlinear regression approach were applied to predict the compressive strength of ready-mixed soil material containing Portland cement, slag, sand, and soil in mixture. The data used for analyzing were obtained from our testing program. In the experiment, we carried out a mix design with three proportions of sand to soil (e.g., 6:4, 5:5, and 4:6). In addition, blast furnace slag partially replaced cement to improve workability, whereas the water-to-binder ratio was fixed. Testing was conducted on samples to estimate its engineering properties as per ASTM such as flowability, strength, and pulse velocity. Based on testing data, the empirical pulse velocity-strength correlation was established by regression method. Next, three topologies of neural network were developed to predict the strength, namely ANN-I, ANN-II, and ANN-III. The first two models are back-propagation feed-forward networks, and the other one is radial basis neural network. The results show that the compressive strength of ready-mixed soil material can be well-predicted from neural networks. Among all currently proposed neural network models, the ANN-I gives the best prediction because it is closest to the actual strength. Moreover, considering combination of pulse velocity and other factors, viz. curing time, and material contents in mixture, the proposed neural networks offer better evaluation than interpolated from pulse velocity only.

Differences in the Control of Anticipation Timing Response by Spatio-temporal Constraints

  • Seok-Hwan LEE;Sangbum PARK
    • Journal of Sport and Applied Science
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    • 제7권2호
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    • pp.39-51
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    • 2023
  • Purpose: The purpose of this study was to investigate differences in the control process to satisfy spatial and temporal constraints imposed upon the anticipation timing response by analyzing the effect of spatio-temporal accuracy demands on eye movements, response accuracy, and the coupling of eye and hand movements. Research design, data, and methodology: 12 right-handed male subjects participated in the experiment and performed anticipation timing responses toward a stimulus moving at three velocities (0.53m/s, 0.66m/s, 0.88m/s) in two task constraint conditions (temporal constraint, spatial constraint). During the response, response accuracy and eye movement patterns were measured from which timing and radial errors, the latency of saccade, fixation duration of the point of gaze (POG), distance between the POG and stimulus, and spatio-temporal coupling of the POG and hand were calculated. Results: The timing and radial errors increased with increasing stimulus velocity, and the spatio-temporal constraints led to larger timing errors than the temporal constraints. The latency of saccade and the temporal coupling of eye and hand decreased with increasing stimulus velocity and were shorter and longer respectively in the spatio-temporal constraint condition than in the temporal constraint condition. The fixation duration of the POG also decreased with increasing stimulus velocity, but no difference was shown between task constraint conditions. The distance between the POG and stimulus increased with increasing stimulus velocity and was longer in the temporal constraint condition compared to the spatio-temporal constraint condition. The spatial coupling of eye and hand was larger with the velocity 0.88m/s than those in other velocity conditions. Conclusions: These results suggest that differences in eye movement patterns and spatio-temporal couplings of stimulus, eye and hand by task constraints are closely related with the accuracy of anticipation timing responses, and the spatial constraints imposed may decrease the temporal accuracy of response by increasing the complexity of perception-action coupling.