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961.
This article presents the implementation and application, to two complex machines, of two holography methods called CIBNAH (Complex Intensity Based Near-field Acoustic Holography) and MRNAH (Multi Reference Near-field Acoustic Holography) based on residual spectra. The first is a newly developed method that uses complex sound intensity as its basis and hence bypasses the need for reference signals. Here, several approaches are presented to validate both methods and to investigate each method’s advantages and limitations. 相似文献
962.
《AEUE-International Journal of Electronics and Communications》2014,68(8):763-766
There is a considerable interest in the antennas which have high power handling capacity with beam steering functionality. The design of narrow side waveguide slot-array antenna for high power applications is introduced in this paper. An approach to achieve a uniform radiation slot waveguide antenna is presented. The large scale array antenna can be composed of such antenna cells. Moreover, it is possible to realize beam steering in the azimuth direction by adjusting the broad wall dimension of the waveguide. Besides, this slot waveguide antenna is expected to have high power handling capacity in vacuum environment, because there is no dielectric or electric field enhancement inside the antenna. 相似文献
963.
This paper presents an analysis of the combining mechanism for status information postulated by the mathematical formulation of the theory of status characteristics and expectation states. Six lemmas on the basic features of the combining mechanism are derived from the formulation and discussed. Further, four theorems that illustrate the implications of the particular combining mechanism for power and prestige orders are presented and proven. 相似文献
964.
965.
966.
An improved progressive preconditioning method for analyzing steady inviscid and laminar flows around fully wetted and sheet‐cavitating hydrofoils is presented. The preconditioning matrix is adapted automatically from the pressure and/or velocity flow‐field by a power‐law relation. The cavitating calculations are based on a single fluid approach. In this approach, the liquid/vapour mixture is treated as a homogeneous fluid whose density is controlled by a barotropic state law. This physical model is integrated with a numerical resolution derived from the cell‐centered Jameson's finite volume algorithm. The stabilization is achieved via the second‐and fourth‐order artificial dissipation scheme. Explicit four‐step Runge–Kutta time integration is applied to achieve the steady‐state condition. Results presented in the paper focus on the pressure distribution on hydrofoils wall, velocity profiles, lift and drag forces, length of sheet cavitation, and effect of the power‐law preconditioning method on convergence speed. The results show satisfactory agreement with numerical and experimental works of others. The scheme has a progressive effect on the convergence speed. The results indicate that using the power‐law preconditioner improves the convergence rate, significantly. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
967.
Digital watermarking is the process of hiding information into a digital signal to authenticate the contents of digital data. There are number of watermarking algorithm implemented in software and few in hardware. This paper discusses the implementation of robust invisible binary image watermarking algorithm in Field Programmable Gate Array (FPGA) and Application Specific Integrated Circuits (ASIC) using connectivity preserving criteria. The algorithm is processed in spatial domain. The algorithm is prototyped in (i) XILINX FPGA (ii) 130 nm ASIC. The algorithm is tested in Virtex-E (xcv50e-8-cs144) FPGA and implemented in an ASIC. 相似文献
968.
969.
970.
In order to manufacture the fibre glass wind blades, one kind of mould embedded with heating wire is used not only for making numerous ‘copies’ of the original sample, and also heating the mould to a certain temperature for curing. The heating wire is embedded in fibre glass as a sandwich structure, and it may break after a long time usage at high temperatures. In this study, a high voltage discharging (HVD) circuit is used to trigger HVD at the breakpoint, which generates heat and therefore causes temperature increase at the corresponding front surface, one infrared camera is used to monitor the temperature evolution. It successfully and quickly detects breakpoints in spar moulds. 相似文献