Abstract:In this paper, based on linear elastic and small deformation theory, an asymptotic distributed transfer function method (TFM) is presented for static deformation, free vibration and buckling analysis of isotropic/composite thin conical shells, where Fourier series expansion, Laplace transform, perturbation technique are applied. Synthesizing the transfer functions of sub-segments, the TFM solution is worked out for combined shells composed of several conical shell segments with different conical angle, thickness, complex boundary conditions and middle-supported constraints. Numerical results shows that this asymptotic TFM solution is of very high precision.

Abstract:In this paper, the distributed parameter transfer function method is applied to analyzing the vibration and stability of composite combined beams under axial compression. The Hamiltonian formalism of a modified mixed variational principle about the symptic variables is established using Legrendre transformation with spatial variable as independent variable instead of time. The state-space equations in Laplace transform domain is derived from using Hamilton's principle and Laplace transform. The unified and closed form transfer function solutions are obtained for vibration frequencies and buckling loads under arbitrary boundary restrictions. The influences of the first and high order shear deformation, torsion deformtion, rotary inertia, length-to-thickness ratio and material anisotropy on natural frequencies and buckling loads are investigated. Numerical examples are provided to demonstrate the efficiency and suitability of the methodology.

Abstract:The 3-D hypersonic chemical non-equilibrium flow over reentry capsule is simulated numerically. The full Navier-Stokes equations are taken as the governing equations. The chemical non-equilibrium air model is considered and seven species are N₂、O₂、NO、N、O、NO⁺、e^-. Using NND Scheme for shock capture and implicit scheme to deal with the chemical source terms, the numerical results are in agreement compared with the experimental data. The perfect gas results are given for analysis of the real gas effect.

Abstract:In this paper the method of a bank-to-turn missile autopilot design is studied. The unsquared yaw-roll channel model with serious coupling is squared by first using inner closed-loop method firstly. Then the autopilot is designed using the multivariable frequency-domain approach based on the Nyquist array method. The simulation shows the efficient decoupling.

Abstract:The paper discusses the basic principles of extinquishing the forest fires by blast and its feasible research direction. As the first step, flows of blast waves near the earth are simulated numerically by use a new ENO scheme which was simple structure and efficient to use.

Abstract:M-SiO₂ aerogels catalysts(M=Cu or Co)are prepared by sol-gel process and supercritical drying. The resulting aerogels are characterized using transmission electron microscopy (TEM), XRD and nitrogen adsorption analysis. Their catalytic behavior for CO oxidation has been studied. The results indicate that Cu-SiO₂ or Co-SiO₂ catalysts have high catalytic activity at 100-400℃.

Abstract:The composition and electromagnetic property of the electromagnetic wave absorbent prepared from magnetic fine powder and PE were studied. The result shows: the added amount of PE has different influence on the whole frequency range. When the added amount of polycarbonsilane is 20 percent, the reflection loss is more than 6dB, and the frequency width is 2 GHz respectivly.

Abstract:Some phys-metallurgical problems related to direct spheroidization of carbide in the process of fine-rolling were analyzed and investigated in this paper in accordance with the author's viewpoint that the morphology of carbide phase in product of eutectoid reaction might be affected by grain size of austenite mother-phase in steels. It is concluded that when a hypoeutectoid steel with super-cooled mono-phase austenite microstructure is fine-rolled at the temperature bellow the equilibrium point of Ae1 in Fe-C diagram, the austenite grains would be refined due to previous' over-precipitation' of ferrite along grain boundaries and deformation bands. At the same time, the eutectoid reaction of intra-grains instead of that along the boundary is induced with the inerease of the rolling rate. While the as-rolled steel stays briefly at the rolling temperature, carbide in the steel may be better spheroidized.

Abstract:The combination of SLIP scheme and LU-SSOR method is used to predict the steady-state aerodynamics of trans-sonic ogive dispenser at Mach number 0.94 to 0.98; and the modified B-L turbulence model is applied in solving axisymmetric Navier-Stokes equation. Computed surface pressures of dispenser without cave have been compared with experiments as well as Sahu's numerical results and are found to be in good agreement; The results of cavity flow are also found to be reasonable.

Abstract:The ballistic simulation model is established for a rocket. A lot of simulation target practice of the rocket is done with Monte-Carlo method to the rocket under none-control condition. The allowable deviations of motion parameters of the rocket at a series of time-points in the power-flight phase are statistically counted from all success trajectories. By setting up motion parameters at above mentioned time-points as initial conditions respectively, the dispersion of falling points to the ground is analysed by simulation regarding to the influence of motion parameter deviations and the other random deviations. The suitable simple control terminal point and its deviations of motion parameters are found out, which provide useful information for designing simple control system of the rocket.

Abstract:In this paper, the alcoholysis products synthesized by MeSiHCl₂ and MeOH in xylene are examined by IR and ¹H-NMR. The results indicated that the concentration of each composition can be calculated using the Si-H bond and phenyl group absorption peak as spectrum-band of quantitative analysis through the calibration curve and the scaling method in the IR analytical means, and also it can be established using the normalization method through the analysis of the different chemical shift parton H and a series of quantitative analytic calculations in ¹H-NMR. Both methods are simple and rapid. The results of the two methods are compared.

Abstract:In this paper, the property of radar target in the optics region is investigated on the basis of polarimetric and high-resolution radar system. By means of polarization decomposition theory, one complex target is decomposed into three simple targets.Polarization feature parameter extracted to describe the relationship of these simple targets is used in target recognition of four kinds of aircraft. Good results are ebtained.

Abstract:It is a functional extension of the conventional radar for the multi-target resolving. IGAF is an effective tool for the detection and parameter estimation of mono or multicomponent polynomial-phase signals. It is proved to be feasible that the application of IGAF for radar multi-resolving by analyzing the radar data. Some key problems which are remained to be further studied are discussed.

Abstract:This paper proposes a new algorithm of track inition for multiple target tracking. It derives the track detection probability and the false track probability. The analytical expressions for the track detection probability and false track probability are obtained. Monte Carlo simulation is performed to confirm the analysis.

Abstract:Based on the wavelet transform theory, this paper researches into the method of noise image compression and coding in wavelet transform domain, which removes the noise and compresses and encodes the image in wavelet transform domain simultaneously, and obtains good offects in both respects. The experimental results given at the end of this paper demonstrate the effectiveness of our algorithm.

Abstract:In tactical SA, it is important for commanders to decide the temporal order of events. But imprecise observations make it diffcult to make. In this paper, hypothesis detection theory is introduced into temporal reasoning, and a new method to decide the temporal order of two events under stochastic imprecision is developed. The transitivity of the stochastic order is also discussed, which enhances the ability of describing time relation and temporal reasoning in situation assessment.

Abstract:This paper presents a dither technique for suppressing spurs in DDS. This technique converts the phase truncation error sequence into a random sequence by adding dither to the phase accumlator, destroys the period of phase truncation error sequence, and turns the discrete line spurs into random noise, which obtains the improvement of the DDS output spectrum at last. The technique is analysed, the results of this analysis is presented and confirmed by simulation.

Abstract:Digital system models (DSM) are improtant in M&S and evaluation for EW system. This paper describes the designation method for DSM such as object-oriented analysis and based on HLA/RTI of distributed simulation.

Abstract:This paper puts forward a fast efficient algorithm of simulating 3D colorful trees on the basis of deeply studying various kinds of models. The algorithm not only simplifes the topology structure and upgrowth law, but also introduces nice-specialties and simple-calculation and well-controlled stochastic parameters. So generated trees have some good traits, such as varieties and lifelike-graph and fast-speed, The algorithm has achieved standard real-time simulation effect on ordinary PC.

Abstract:In this paper, the concept of multimedia digital watermark is introduced. The present state of this technology is summarized. The hypothesis test procedures of two different algorithms using DCT are analysed, and threshold choice problem is discussed. Computer simulation is done to confirm the conclusions made.

Abstract:In this paper, a high reliability, a hard real-time distributed system and its two switch schemes are introduced at first. Then, the realization of switch technology is discussed. Finally, based on the reliability model of hard real-time dual working system, the two switch schemes are analyzed and compared. The conclusions show: The switch in cluster is superior to the switch in node, and it can not only improve the system reliability and real-time, but also reduce the complexity of the program.

Abstract:The paper puts forward the conception of“time coherence”and the realization policy in HLA. Tits sufficiency is also proved. In order to construct a HLA system, we solve the problems of real-time control and optimistic time synchronization based on HLA time management mechanism by providing the appropriate algorithms and the mathematical proofs.

Abstract:Nowadays, since the a language-based or the library-based approach has been adopted in simulation environmene, the reuse existing simulation models and tools, cannot be resused. Besides, they depend on the operating systems and hardware platforms. Especiarly they are lack of capability to operate over the Internet and the Web. Aiming these disadvantages puts forward a prototype of distributed simulation environment based on Web (DSEW) and makes a case study as well.

Abstract:Binocular matching is a key problem in the field of computer vision. In this paper, we present a model based on cell dynamics, which is from the FACADE theory, to realize binocular matching by a method of“cooperation within orientation plane, competition between disparity plane”.The model helps us to realize a computer vision system based on biological vision theory ,It is different from those normal models in the field of computer vision.

Abstract:The paper discusses the research and implementation of ICMIIP based on Internet, including the implementation of Java ORB complying with CORBA 2.0 specification, and the methods of how to use Java ORB to integrate the legacy application developed on relation data base system and lead them to Internet/Intranet.

Abstract:This system is a child system of aviation reducer CAD system. It reasearches on the conical gear which is the key spare part in the aviation reducerr. Based on AutoCAD desk and compiling procedure with ADSRX and C++ language, it realizes the integration of routine design, verifying caculation, optimization design and parametric drawing. Practice proves that the routine design of this system is right and result of optimization design is perfect, has high engineering applying value.

Abstract:An experiment has been made on the device of magnetic suspending ball to test the effect of the controller designed according to the theory of variable structure control system. The result proves that this kind of controller has the better robusticity of rubust and increases the rigidity of the suspension system. And it is easier to design the controller using the theory of variable structure control systems. Further more this theory can be applied to on all kinds of systems.

Abstract:In this paper, the representation of the prior distribution function is discussed. The bootstrap and random weighted method are given for determining prior p.d.f.In the same time, we study the multiple sensor fusion estimation of prior p.d.d. And, the problems ariring in using Bayesian method is also discussed.

Abstract:The empirical Bayes estimation is derived for the failure rate parameter and the reliability function in the exponential distribution by considering a spline density estimation. Therefore, numerical example is introduced to conpare the performance of this estimation with the classical Bayes estimation using Gamma prior distribution. The results of the simulation show the algorithm is effective.

Abstract:This article discusses the second order stationarity of a dimensional doubly stochastic AR(1)-MA(q) model. By developing a group of linear equations, the explicit necessary & sufficient conditions of the stationarity for this model have presented. lt is a feasible method to test the second order stationarity of this model.

Abstract:This paper discussed some properties of fuzzy measure, internal measure and fuzzy integration on a normal fuzzy measure space which is subadditive and has bounded variation. As a result, the conditional expectation of random variable on such measurable space is defined.