Abstract:The nonlinear high frequency combustion instability process in the liquid rocket engine is simulated with the method of nonlinear dynamics. The gas controlling Navier-Stokes equations are described under the Euler coordinate. The liquid phase controlling equations are described under the Lagrangian coordinate. The two-phase interactions of the gas and liquid are coupled through the sources of equations. The spray process in the rocket engine is described with the theory of high pressure evaporation. The two phase turbulent combustion steady process and high combustion instability in the liquid rocket engine are simulated with the method of computational combustion dynamics. The conclusion is drawn that the high frequency combustion instability in the liquid rocket engine is similar to the strange attractor which looks like Lorenz attractor.

Abstract:The temperature field distribution in the two-layered shell is simulated numerically by using the finite element method. The influence of material properties of the outer shell on the temperature rise in the inner shell is analyzed under a given laser power. The results indicate that the difference of material properties of the outer shell in specific, thermal conductivity as well as its thickness can greatly change the temperature of the inner shell. The thermal wastage in the inner shell between the inner and outer shell are investigated in the process of computation. Moreover, the effect of temperature-depending material properties of the inner shell on its temperature rise is presented. And some significant conclusions are reached by comparing with the temperature field distribution of the one-layered shell irradiated by the intensive laser beam.

Abstract:An airframe/propulsion system integrated design of hypersonic cruise vehicle overall performance analysis model is set up. The parameter sensitivity of the hypersonic cruise vehicle airframe/propulsion system integrated design is discussed. A new design parameters sensitivity analytical method and a new design parameters region classifying method are presented. Based on the vehicle performance analysis, influence degrees of the design parameters are obtained, and the changing region of design parameters is classified.

Abstract:To improve the precision of the aerodynamic coefficients of the projectiles during calculating trajectories and designing projectiles, the drag, lift, pitching moment, roll damping moment, Magnus force and moment of the projectiles are computed by solving N-S equations applying an implicit LU scheme, and considering an algebraic turbulence model and the boundary condition for rotating body surface. It is indicated that the aerodynamic coefficients of the rotating projectiles obtained by means of the numerical simulation are better than those previously obtained by means of the engineering estimate by the comparison of the computing results and the experimental results of the T388 shell, and by the ballistic calculations of a certain howitzer projectile using the aerodynamic coefficients obtained with this technique.

Abstract:The ordered macroporous silica was synthesized using PMMA latex sphere colloid crystal as template and sol of tetrarethyl orthosilicate,water,ethanol and hydrochloric acid as filling fluid.The sol was synthesized according to the volume ratio of Si(OEt) ₄∶H₂O∶EtOH∶HCl=6∶3∶4∶1. The latex spheres were removed by calcinations. Set the temperature program as follows: ramp the temperature at 2℃/min from the room temperature to 300℃, maintain it at 300℃ for 2 hours, ramp the temperature at 2℃/min from 300℃ to 550℃, maintain it at 550℃ for 10 hours, ramp the temperature at 10℃/min from 550℃ to the room temperature.

Abstract:The treatise discusses how to test and evaluate quantitatively the disturbing effectiveness of the fog on the military opto-electronic imaging equipment in the field. It advances a new kind of multifunction target-plate that can be applied to anti-fog jamming test for the opto-electronic imaging equipment.

Abstract:An algorithm for the moving emitter passive location and tracking based on TOA and DOA measurements by a single fixed station is given. This algorithm has some great advantages over the extended Kalman filter (EKF). Furthermore，the two improved methods which combine this algorithm with Kalman filter can obtain better location performance. And the results of the computer simulation prove that they're good methods.

Abstract:By using the analog cascade elliptic filters design method, and the bilinear method of transforming analog filters to digital filters, and the frequency transformation method of digital filters, a simple robust cascading digital IIR filter is designed. The stability of this filter can be assured by setting rational frequency transformation parameters. The internal magnitude bound of this filter can be minimized by using an empirical optimal method of poles and zeros organization. At the end of this paper, an example of designing a cascading digital elliptic band stop filter is provided.

Abstract:After analyzing the echo data of aircrafts based on Low-resolution radar, this paper has defined and obtained some features of aircrafts as an input for classification by FMM neural networks. The results prove that the features are useful to identify the size and numbers of the aircrafts formation.

Abstract:With the appearance of radio frequency interference (RFI) in subsurface penetrating radar(SPR), this paper first analyzes the sources and properties of the RFI signal; and then based on the random property of RFI and the principle of mean square error (MSE),the wave-average filtering method in A-Scan and the median filtering method in B-Scan are discussed for RFI suppression. The performance of the two methods is demonstrated on data collected with SPR and the experimental results are also good.

Abstract:Firstly，the phase-coded pulse compression signal is analyzed. Then the radar clutter model for phase-coded pulse compression radar is proposed based on the radar clutter model for the general pulse radar. Both the probability density characteristics and the spectral density characteristicsof the clutter signal are analyzed by Monte-Carlo method. The correlation characteristics of the clutter signal between the two range gates are also discussed. Finally，for the design of the radar environment simulator, the implementation of the clutter simulation's system is proposed by mixed means of software and hardware.

Abstract:IOs of the external memory are still the key factor to the performance of IO-intensive applications. Based on the systematical analysis of I/O-optimized scheduling policies and their requirement to characteristics parameters of disk, this paper introduces a set of I/O-scheduler-oriented disk characteristics extracting methods. These methods have been proved efficient and introduced into the implementing of Traxtents-Cello scheduler.

Abstract:We describe a MAP-based method for constructing a high resolution image from the noisy undersampled multiframes. Using the aliasing relationship between the high resolution image and the undersampled frames, we develop the algorithms for the reconstruction problem, appropriate for the case where all images are taken under similar conditions. The Bayesian approach uses Laplacian operator to model a neighbor correlation on estimated image. The results of experiments show dramatic improvement in the spatial resolution.

Abstract:A2C2 experiments are introduced, and based on the analysis of data obtained from a series of A2C2 experiments, the relation between organization coordination and organization performance is primarily explored. With the guidance of the conclusions for organization coordination, an algorithm for organizational hierarchical clustering, which is used for Levchuk's three-phase iterative organizational designing, is introduced, and a new thought to improve the algorithm for platform clustering is presented.

Abstract:Filling algorithm of the complex connecting area is studied and a new scan line algorithm for filling area is presented. Using this algorithm, every edge pixel for judgment is labelled, then the area is filled using the scan line. This algorithm is applied not only to simple connecting area, but also to the complex area. And it is efficient, flexible, easy and exact.

Abstract:According to the self-similar nature of the optical surface in microstructure, its structure feature is described with fractal model independent of the scale. Fractal dimension of the polished surface is calculated by structure function. The influences of roughness RMS, error wavelength, measure scale, sampling length and the number of sampling points on fractal dimension are analyzed. On this basis, a new method which applies the first-order autoregressive fractal model to simulating the optical surface is presented. The influences of the definition scale and model parameter on fractal feature and fractal dimension are analyzed. The research indicates that the evaluation method is simple and independent of the scale in certain range when the microstructure of the optical surface is described by fractal dimension.

Abstract:The levitating and propulsive electromagnetic fields of the high speed magnetic levitation vehicle is studied by using the finite element method. The tide of the thrust and levitation force varying along under the running condition is highlighted and an experiential formula is derived. According to the analysis and the calculation, the thrust and levitation force are related to the power angle, and the sixfold frequency undulation is found in thrust and levitation force due to the influence of the discontinuousness of the stator grooves and the material.

Abstract:The question how to translate a time series into a symbolic series is briefly answered by the simplest binary partition. The frame of symbolic tree and calculation method of Shannon entropy are presented depending on the binary partition. The coding method and histogram function of symbolic series are described. The calculation flow chart for symbolic time series analysis is refered to. The signal characteristics, which are from the vibration of both IC engine block and mechanical bearing, are extracted by the measurement of entropy of the symbolic tree.

Abstract:The characteristics of the techniques of the locating and speed-measuring for aerotrain are introduced. Emphases are put on the applications of the counting method of the crosstie and rail cable and the device for determining the absolute position to train locating and speed measuring. Principles and methods of these applications are given, and the source of error is analyzed. Based on these analyses, and taking the current status of maglev in our country into account, solutions of train location and speed measuring for the current stage are provided and relevant test results are given.

Abstract:Terrain aided navigation (TAN) is the concept of using terrain height variations below the aircraft to obtain an estimation of the position that is used to limit the error in the INS. A new TAN approach using fading memory is proposed. The basic idea of this approach is using a new type correlation functional value to estimate the navigation position. The correlation function is defined by all the historical measurements with fading memory weight. A set of simulations shows that the method improve the precision and speed of TAN compared with TERCOM.

Abstract:The two stages of the ambiguity solution, ambiguity estimation and ambiguity search, have been researched on. Through the improved matrix decouple method and OMEGA method, the speed of the ambiguity solution has increased. It is proved that ambiguity solution can be made correctly in two to three minutes and computed almost in real time.

Abstract:The estimation of the variable distribution parameters of the normal sample under the hierarchical prior informations is discussed.At the same time,the recursive form of the estimator of the state variables for the linear model is constructed. Furthermore, as for the application of this method,some practicle problems are considered.

Abstract:After analyzing the characteristics of the model and integrated computing for reliability of the large scale complex systems, a new model named Composite Logic Tree Model (CLTM), its concept and modeling principles are put forth. And then a recursive algorithm based on CLTM for integrated reliability computing is designed. We have developed a software that can be used to establish graphic CLTM and implement comprehensive reliability analysis through interactive visualized interface, which has been successfully applied to the mission of an aerospace system analysis.

Abstract:By considering the credibility of the prior information, a new Bayesian estimation algorithm is studied, and the estimation of normal distribution parameters is provided. Taking the estimation of the dispersion of the missile falling points as an example, the conclusion is drawn that by considering the credibility of the prior information, the new algorithm of Bayesian estimation is obviously improved,that is, it is of a better credibility.