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981.
982.
Among data acquisition techniques in digital photoelasticity, the integrated phase shifting technique (IPST) can real-time analyze the photoelastic parameters at a video rate of the high speed CCD camera. In this paper, fourteen algorithms are described by different configurations of the rotating an analyzer at a constant rate and an output quarter-wave plate at another constant rate. The theoretical comparisons of the algorithms are given by the simulated phase distributions of the isochromatic and isoclinic parameters of the disk under two cases that the load keeps unchangeable or linear increasing in exposure time of the camera. Then a guideline is given to alleviate the influence of the load changing with time on the IPST. 相似文献
983.
Bin Li Xiaofang Zhu Li Liao Zhonghai Yang Baoqing Zeng Lieming Yao 《International Journal of Infrared and Millimeter Waves》2006,27(7):941-947
Two kinds of novel helical slow wave circuit, supported by Chemical Vapor Deposition (CVD) diamond, are presented. They are
applying in miniaturized millimeter wave helical traveling wave tube. Cold test characteristic of these circuits are simulated
by MAFIA code. Higher performances are achieved with smaller size, compared with conventional circuit supported by BeO rods.
The nonlinear analysis is implemented by Beam and Wave Interaction (BWI) module, which is a part of TWTCAD Integrated Framework.
Results have been found to be consistent with the expectation. It should be wider apply in microwave and millimeter wave vacuum
electronic devices. 相似文献
984.
The dynamics of two uncoupled distinct Chua circuits driven by a common direct current voltage is explored experimentally.
It was found that, with increasing current intensity, the dominant frequencies of these two Chua circuits will first vary
at different speeds, approach an identical value for a certain current intensity and then separate. Techniques such as synchronization
index and phase difference distribution were employed to analyze the phase coherence between these two Chua circuits. 相似文献
985.
Bao Gang XU 《数学学报(英文版)》2007,23(6):1059-1062
In this paper, we prove that every plane graph without 5-circuits and without triangles of distance less than 3 is 3-colorable. This improves the main result of Borodin and Raspaud [Borodin, O. V., Raspaud, A.: A sufficient condition for planar graphs to be 3-colorable. Journal of Combinatorial Theory, Ser. B, 88, 17-27 (2003)], and provides a new upper bound to their conjecture. 相似文献
986.
Ultrasonic instrument for measuring bolt stress 总被引:1,自引:0,他引:1
An ultrasonic instrument for the accurate measurement of bolt stress is described. The instrument, which is based on the pseudo-continuous-wave technique, uses carrier phase detection to track the frequency of the mechanical resonance of the bolt. The basic operation of the instrument and the experimental results obtained are discussed. 相似文献
987.
关于RLC电路谐振特性曲线的对称性问题 总被引:3,自引:0,他引:3
通过引入不对称因子δ从理论上讨论了RLC谐振回路的谐振曲线相对于谐振频率的牟称性问题,计算表明,在低Q值下谐振曲线是不对称的,为使整条曲线具的近似的对称特性,要求回路的Q〉100。 相似文献
988.
Most lenses composed of spherical or aspherical surfaces have symmetrical focusing properties about an optical axis. On the other hand, unconventional optical systems such as cylindrical lenses, astigmatic or progressive power glasses have axially asymmetrical focusing properties. In this study, the method of measuring focusing properties by the moire technique is extended to asymmetrical lenses. Some unconventional lenses were experimentally tested, and the focusing power in the interesting region and azimuthal direction of the aperture was evaluated. 相似文献
989.
W. Eymann 《Chromatographia》1997,45(1):235-242
Summary A well established totally automated testing procedure for characterization of RP materials is presented. The test is suited
to the determination of hydrophobic and silanophilic interactions, as well as trace metal impurities on silica surfaces. it
includes measurements of stationary phase stability and shows column performance at two different pH conditions. The very
different parameters examined readily reveal batch to batch reproducibility and are therefore suitable for laboratories dealing
with quality control and validation of columns.
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996 相似文献
990.
Accuracy and sensitivity of a hole drilling and digital speckle pattern interferometry combined technique to measure residual stresses 总被引:4,自引:2,他引:2
This paper reports on the accuracy and sensitivity of digital speckle pattern interferometry (DSPI) when it is combined with the hole drilling technique for measuring residual stresses. The in-plane displacement field generated by the introduction of a small hole is determined using an automated data analysis approach. This method is based on the calculation of the optical phase distribution through a phase-shifting method and the application of a robust iterative phase unwrapping algorithm. It is experimentally demonstrated that residual stresses can be measured with a relative uncertainty of 7.5%. It is also shown that the minimum value of residual stress that can be determined with the DSPI and hole drilling combined technique is about 10% of the yield stress of the material. 相似文献