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521.
Gupta Someshwar C. Hall Thomas G. 《IEEE transactions on aerospace and electronic systems》1968,(4):499-504
This paper considers the design of PCM signals with system constraints using Pontryagin's maximum principle. The transmitter signal as well as the correlation signal are determined while maximizing the output signal-to-noise ratio. Both the single and three-pole transmitter filters are considered. An upper bound has been obtained on the performance of PCM signals with constraints. 相似文献
522.
In this paper, the results of calculating the processes of two fuel mixture combustion in different proportions are presented.
The values of temperature, thermal capacity, specific gas constant and isentropic expansion ratio of combustion products are
given. Also shown is the distinction of thermodynamic properties from the additivity law. 相似文献
523.
A finite element statement of solving problems on stability of reinforced elliptic cylindrical shells taking into account
momentness and nonlinearity of their subcritical stress strain state is presented. The explicit expressions for displacements
of noncircular cylindrical shell elements as rigid bodies are determined by integrating the equations obtained by equating
the components of linear strains to zero. These expressions were used to construct the form functions for an efficient quadrilateral
finite element of natural curvature. An efficient numerical algorithm of nonlinear deformation and stability of shells was
developed. The stability of reinforced elliptic cylindrical shells under combined loading by bending moment, transverse boundary
force and internal pressure is analyzed. We also examine how the critical loads are affected by the strain nonlinearity and
ellipticity of shell deformation at the subcritical stage. 相似文献
524.
I. S. Akhmed’yanov 《Russian Aeronautics (Iz VUZ)》2010,53(2):230-234
To complete study [1], the procedure of applying the numerical quadrature method to analyzing the shells of revolution under
axisymmetrical loading is presented. 相似文献
525.
A. N. Markushin V. K. Merkushin V. M. Byshin A. V. Baklanov 《Russian Aeronautics (Iz VUZ)》2010,53(1):63-68
The test results of a conventional combustion chamber with the improved structure are presented. The concentration of toxic
substance emissions is reduced as compared with combustion chambers of the similar type. 相似文献
526.
To calculate the unsteady helicopter motion, we propose a simplifying approach consisting in the fact that the numerical solution
of equations of nonlinear nonstationary aerodynamics and flight dynamics are made successively in time intervals. As an example,
the results of calculating the helicopter motion in descent are presented. The mathematical model and algorithm can be used
for calculating the unsteady motion of different helicopters. 相似文献
527.
A. I. Golovanov 《Russian Aeronautics (Iz VUZ)》2010,53(3):243-249
The constitutive relations and plastic flow rule are derived from the thermodynamics equations. The known procedures of determining
the plastic strain rate value are described. A calculation algorithm is presented that is based on the incremental loading,
linearization of the virtual power equation and the projection method. A numerical example is presented. 相似文献
528.
In this paper, the results of an experimental study concerning average heat transfer in an annular channel with flow swirling
by an endless screw and spherical grooves on the convex surface are presented. Also analyzed is the heat and hydraulic efficiency
of grooves application under conditions being considered. 相似文献
529.
Jao J.K. Lee C.F. Ayasli S. Haywiser E.J. 《Aerospace and Electronic Systems Magazine, IEEE》1999,14(6):5-9
In July and October 1995, a large-scale airborne SAR experiment was conducted in the Yuma Proving Ground, Yuma, Arizona, to investigate ground penetration radar phenomenology and buried target detection. This paper describes the Yuma experiment and measurement results for many tactical, utility, and environmental targets deployed in the test 相似文献
530.
A new structure for the separation and tracking of uncorrelated sources through the use of a 2-dimensional adaptive array is proposed and investigated. The structure consists of a matrix preprocessing beamformer designed to result in outputs which are due to individual sources in the steady state. The preprocessing weights of the beamformer are calculated using the estimated locations of the sources and are updated periodically. Continuous estimation of the source locations is accomplished by using the beamformer outputs to adaptively eliminate correlated components in a reference element of the array while the structure proposed may have rather erratic initial convergence behavior, it has the advantages of being simple to be implemented, fast in tracking, and well suited for applications in mobile communication systems for increasing system capacity 相似文献