Diffusion bonding of TC4 and QAL1031.5 was carried out under the condition of 850 ℃, 8 MPa and 30 min, but there are cracks existing on local area of diffusion zone. Microstructure of diffusion zone was analyzed using scanning electron microscopy (SEM), and diffusion distance and concentration distribution of elements were analyzed using EDS. The result shows that the transition zone thickness is 10 μm. Diffusion distance of element increases with increasing bonding time followed a parabolic law: x2=Kp(t-t0), and phenomenon of transition zone moving to TC4 are observed which is so called kirkendall effect . The occurrence of the cracks on the diffusion zone was studied in the theory of interfrcial pore and the reason for microcracks produced and improvement methods are found out. Thus, approving diffusion joint is attained by improving the welding process.

The microstructure and mechanical properties of as cast AZ91Nd(neodymium) magnesium alloys were studied by microstructure analysis, mechanical property testing and analysis of fracture surface, where w(Nd) is 0, 0.1%, 0.3%, 0.5%, 1.0%, 1.5%. The results reveal that the element Nd added into AZ91 exists in the forms of both solid solution and intermetallics Al11Nd3. It has great effects on refining grains of αMg and βMg17Al12 , depressing the precipitation of secondary βMg17Al12 and transforming the partially divorced eutectic into the fully divorced. Nd effectively improves the tensile strength, ductility and hardness of AZ91 alloy due to the effects of solidsolution strengthening, precipitation strengthening as well as finegrained strengthening.

The mechanism of crack propagation at the interface between coating and substrate was analysed under the condition of yielding strength and residual stress mismatches along the interface. The dimension of plastic zone at the crack tips was numerically calculated using the correlative theory of dislocation and crack. Calculation results show that when the interfacial crack propagates from low strength zone to high strength zone, the residual compressive stress and yielding strength of the high strength zone lead to the reductions of the length of plastic zone and the opening displacement of crack tip. As a result the propagation of the crack at the interface is retarded.

A minibus concept design method using a parametrized model of the frontal crashworthiness of the vehicle structure was suggested. The effects of the major stiffness parameters of the bottom energyabsorbing structure of vehicle on the passenger compartment deformation, the vehicle deceleration, and the bottom energyabsorbing behavior during crash were analyzed. The method to control the energyabsorbing behavior of the bottom energyabsorbing structure and to match the behavior with the passenger compartment stiffness parameters by means of the suggested parametrized model to ensure the vehicle frontal crashworthiness was demonstrated. The design targets, design procedure and design technique of the vehicle body structure crashworthiness during minibus concept design phase were given. The rapid determination of the energyabsorbing indexes of the different vehicle components by the suggested model was realized, providing a solid basis for the subsequent detailed design.

The transient flow field around two simplified shape cars when they meet oppositely sidebyside in tunnel was simulated by means of the sliding interface and the moving mesh features offered by a commercial computational fluid dynamics(CFD) software. The differences between the transient and the steady simulations, the transient aerodynamic characteristics(including the wake structure and the aerodynamic coefficients) of the cars, the interaction between the air flow and the cars under the condition of opposite meet sidebyside were analyzed. It was found that it is feasible to use CFD to simulate the transient aerodynamic phenomenons and the aerodynamic coefficients of the cars change sharply like sinusoidal functions. The aerodynamic forces on the cars when they meet have significant effect on the car handling stability.

：According to the driving behavior of the four wheel drive vehicle on the sand terrain, an engine throttle controller for the traction control system(TCS) on the sand terrain was developed using the combination of the PI control and the threshold control. The road test of the TCS based on the target controller for the vehicle driving straightaway was performed on the sand terrain of a sandpit. The test results show that the developed throttle controller can effectively avoid the excessive spin of the driving wheels and prevent the driving wheels from sinking into the sand, so that the driving resistance of the vehicle can be reduced and the vehicle driving ability and traction performance can be improved.

Aiming at the oversteering trend of a SUV prototype in the steady circular test with full load, a virtual prototype of the vehicle was built using MSC.ADAMS/CAR software, the virtual steady circular tests were performed and validated with the physical prototype test results. By studying the effect of the construction parameters on the vehicle steady circular response, a version incorporating the thickening the antiroll bar of the front suspension, regulating the roll rate distribution of front and rear suspension was put forward, and the comparative analysis of different distributions was performed in the virtual prototype. The results show that when the roll rate proportion of front suspension to rear suspension is modified from 1.2 to 1.8, the oversteering trend was eliminated with a tolerable understeering characterstic. The conclusion was used in the physical prototype, and the suggested version is proved feasible by the test results of modified prototype.

A whole process of developing the type W305 torque converter was presented in detail. Five versions of the vane cascade systems for the torque converter with the same basic geometric parameters were designed and the steady comparative experiments of these 5 versions versus the base version of W305 torque converter were performed. The simulation of the internal flow field inside the converter was made to reveal the substantial cause for the performance improvement of torque converter. Both the experiment and the simulation results show that the proposed method for the torque converter design is reasonable and accurate.

A two degrees of freedom multiaxle vehicle steering model was established and the steering center position, the relationship between the steering angle and the vehicle velocity, and the minimum turn radius were deduced based on a zero sideslip angle proportional control. The results indicate that the system stability is decided by the vehicle barycenter position and the lateral stiffness of the tire. Under this control, the steady lateral acceleration value is diminished obviously and the yaw angular velocity changes little under any vehicle velocity. The system responds rapidly, the vehicle steers smoothly, and its handling stability is improved prominently.

The HCCI operating region of an internal combustion engine with ethanol as the fuel was studied experimentally on a single cylinder HCCI engine modified from a CA6110 diesel engine. The HCCI operating regions expressed by the mean indicated pressure and engine speed were found out, and the mean indicated heat efficiency and the emission performance were analyzed. The experimental results show that HCCI can obtain high mean indicated heat efficiency up to 60％ and mainly be effected by the engine load and hardly by the engine speed. Only little NOx is formed with the maximal indicated specific emission of NOx only 1g/kWh .But the CO and HC emissions are high, even at the region of the minimum HC and CO emission, they can reached 5 g/kWh, being sensitive to load.

A frontal vehicle location and identification method based on the fractal box dimensionality(FBD) was proposed to help the auto-guided vehicle development. The horizontal edge informations of the located vehicle were obtained by the image difference and linear filtering. The search area of the FBD was reduced by the statistical method. The potential vehicle region was determined by calculation of the FBD and the location of the vehicle was achieved in this region. At the same time, a validation algorithm based on the symmetry measures was proposed to check the correctness of the vehicle location. The tests of the vehicle images under different environments and illuminations show that the proposed method is characterized by good robustness and reliability.

Abstract：In order to improve the emergency response of freeway, an optimization model for emergency vehicle dispatching was established by integer programming. Three kinds of dispatching strategies were qualitatively analyzed, and they were compared predigestedly. The results show that the nearest server dispatching can reduce emergency response time greatly, the model server dispatching improved response significantly, confirming the effectiveness of the proposed model.

Against the limitation of the traditional mathematical programming to deal with the transit network system optimization,a simulation optimization model based on the tabu search algorithm was designed.Through many simulation experiments, more than half gained optimal solution which the algorithm could get,and the results appeared steady. The simulation experiment results show that the application of the algorithm to the study of the transit network simulation optimization is of great practical value.

Since the material volume is constant during plastic deformation, measuring the volume of workpiece with complicated shape is significant for plastic precision forming. Based on the authors' patent for invention, the working principle, structure and measuring method of an arbitrary volume measuring apparatus was introduced. The whole and local volume of an auto connecting rod formed in each forming step was measured. The invented apparatus is characterized by simple structure and high accuracy. It can not only measure the volume of workpiece with arbitrary form and density larger than water, but also that with density less than water.

A new type of precise linear actuator using the piezoelectric stack as actuating element was presented. The stator clamps the rotor by a flexure hinge clamping structures in symmetrical directions. The working principle of the actuator was analyzed, and a mathematic model of the mechanical system was set up. The mechanical structure was simulated by the MSC Patran/Nastran software. The experimental test of the actuator prototype was performed and the test results were in agreement with the theoretical analysis results basically. The actuator prototype can move with speed 1.52 mm/min, and the minimum step size (moving resolution) is 3.35 nm. The actuator works stably and reliably, may be used in the domain of precision engineering.

Introducing the concepts of design for assembly and design for manufacturability into the development and production of the optical communication equipments, the rational construction design and assembly techniques of the polarizationmaintaining dual fiber collimator were discussed to achieve the objects of low insertion loss and high reflection loss of the collimator, and its packaging technology based on the concept of design for test was proposed and has been utilized in series production to enhance its productivity and eligibility.

The expression of the complex equipment failure rate under the normal operating conditions were researched based on the renewal theory. The results show that the limit of the complex equipment failure rate λ(t) is a integral expression under the arbitrary failure distribution, only when the failure obeys the exponential distribution, as a special example, the limit is a constant. The theoretical research results have been strongly supported by the actual operating failure rate λ(t) of complex equipment. This research has important theoretical value and practical meaning for guiding the operation, detecting test and diagnosis, maintenance and repair of the complex equipments.

To imitate the structure of nonsmooth surface of earthworm and the wearresistance performance caused by its body secrete, experiments with mixing lubrication of oil dripping were performed on a friction test bench on three bionic nonsmooth surfaces: hollow pit surface, throughhole surface with leading angle, and throughhole surface, which are similar to the body surface of earthworm. Results show that the nonsmooth surface with throughhole, which is most similar to the back surface of earthworm, possesses the best lubrication and wearresistance characteristics. The mechanism of the influence of bionic nonsmooth surface on the wearresistance was analyzed. It was found that proper designs of the hole geometry and the distribution of holes on the surface can effectively improve the wear performance.

The gray incidence degrees between the elements, including C, Re, Mn etc, and the properties, such as contactangle, hardness, cost etc, of the materials of bionic plow moldboard were computed using the test data. Quantitative relationship between elements and properties indices was analyzed. This study provides a research method for the development of bionic drag reduction materials for soilengaging components of terrain machinery.

Taking the conical thread as the object of study, a subpixel image detection method for the mechanical part linear edge based on the support vector regression was proposed. Through processing the conical thread image recorded by the charge coupled device(CCD), the pixel characterization of the straight portion of the thread form could be obtained with the algorithm of median filter, binary transform etc, to make up the training set. The support vector machine for regression was trained by the training set and the straight line equation of the thread form was obtained which is the expression of the subpixel . Making use of it to detect the main parameters of the conical thread, the effect of the discreteness of the CCD and the system noise on the detection results were significantly reduced. The experiment results show that the suggested method is characterized by high detection speed and high precision.

A new approach is proposed for modeling heterogeneous objects made of functional gradient materials. The theory of discrete pilingup is applied to model the geometry of the object and an algorithm named “volume” is employed to build the discrete geometrical models in CATIA. The functional gradient material modeling is based on the theory of gradient sources, by which the geometrical features in threedimensional space can be selected as a grading source and the composition function of a material can be obtained, thus the material composition information of the object can be determined. To meet the demands of material modeling, three existing Boolean operations are expanded to six. Two design cases by this approach are presented.

We present the ObjectOriented Algebraic PetriNets model(OOAPN) based on the achievements in software methodology. OOAPN supports the ObjectOriented concepts, the system analysis and modeling of ObjectOriented software. As a hybrid of algebraic and PetriNets theories and ObjectOriented technology, OOAPN proves to be a effective method in the development of formatting and intelligent software environments, it also enhances the abilities of dynamic modeling of concurrent systems and advanced modeling of complicated systems.

Due to the fact that the distributed vision composite navigation system of the autonomous mobile robot requries making use of the overall vision to perform the absolute locating of the robot, aiming at the problem of that when the robot locates far from the camera, the locating precision will deteriorate seriously, a multicamera parametrially partitioned calibration method suitable for large scenes was proposed. The relation between the total working region of the mobile robot and the effective region of every camera was described using the concept of set. A camera parametric calibration model was built based on the perspective transformation matrix from the space plane of the hole model to the image plane of the camera. The calibration experiment with 4 cameras in a 9.6 m×6.4 m region and the error analysis shows that the total mean error is only 7.96 mm.

In view of the difficulties caused by the timevarying communication delay in the teleoperation, the reasons for the timevarying communication delay was analyzed. To solve the problem a timevarying communication delay identification method was proposed and this method can converge the timevarying communication delay parameter quickly. This method was combined with the wave integrals and a control scheme especially proposed for the timevarying communication delay. The effectiveness of the proposed scheme has been demonstrated through the simulations.

A technique of ascertaining the prediction factors and the prediction objects,e.g. the values of the electromagnetic interference(EMI), from the early parameter measurement data was proposed. The data were classified based on their statistical character,the fuzzy relation set was ascertained from the merging of the fuzzy implication relations, and the membership functions as the correction factors of the prediction scope were constructed. The predicted values of the EMI were obtained from the designed parameters or the theoretical data under the rational judging criteria. The suggested technique can avoid the difficulties of the conventional electromagnetic compatibility(EMC) prediction method in model solution and application limitation. The computation example illustrated its usefulness in the vehicle EMC design.

Two necessary techniques, orbital transfer and phasing were introduced for coplanar aeroassisted space rendezvous. The Hohmann orbit transfer technique for coplanar high earth orbitlow earth orbit(HEOLEO) transfer and its phasing were analyzed. The coplanar HEOLEO aeroassisted orbital transfer technique was studied in detail. The optimal control theory was applied to resolve a typical optimal trajectory of the aeroassisted orbital transfer from a HEO to a LEO and the orbital phase angle of the OTV flying in the atmosphere was obtained. Based on the space rendezvous thcory, a calculation expression of the standard phase angle that must be complied with for the coplanar HEOLEO aeroassisted space rendezvous was derived and the phasing problem of the aeroassisted space rendezvous was analyzed. The Hohmann technique and the aeroassisted technique were compared and concluded that the latter can not only save the fuel but also rendezvous in a reasonable time.

Focusing on the requirement of onorbitservicing spacecraft to targeter in eccentric orbits, the initial conditions for the chaser flying around the targeter and the optimal control algorithm used to keep the flyaround orbit under perturbance were presented. With detailed analyzing the time variant and relatively linearized formulas and their analytic solutions, the necessary conditions for the chaser flyaround were acquired. To consider the safety, the conditions for the targeter to locate at the center of flyaround orbit and its design under given chaser shape and distance were presented. In view of the influence of perturbance, a discrete LQR optimal controller with constraint control vector to keep the chaser in the scheduled orbit was designed. Three control error boxes enabling the controller to work in the reasonable error areas to avoid fuel wastage for the error measure were also allocated. An example design was validated successfully by a simulation.

Regarding the structure disturbance as the propagation of a traveling wave, the control of the structure disturbance may be realized by the active control of the propagation paths of the traveling wave. When the disturbance energy upstream is restrained or absorbed by a traveling wave controller, the energy downstream may be minimized. The structure beam response control method based on the traveling wave model was discussed theoretically. The theoretical traveling wave model was applied to a long thin beam with piezocrystal actuators and the traveling wave active control law for the condition of making measurement upstream and performing control downstream was derived and the control compensator formula of the flexural waveguide in the form of transcendental function was deduced. The simulation results show that the suggested traveling wave control is quite effective.

A novel method to recover the weak harmonic signals from the measured data contaminated with the chaotic interference was proposed. A new phase space projection method was established to separate the harmonic signals from the strong chaos by combining the phase space reconstruction with the cosine transformation based on the geometry of chaos. The power spectrum estimation was used to extract the frequency of harmonic signals, and the leastsquares procedure was applied to increase the recovery accuracy of the harmonic signals. Computer simulation verified that this method have high stability and reliability in recovering the weak signals in the chaos.

Constantamplitude polynomialphase signals (PPSs) are characterized by their phase polynomial coefficients. It is usually difficult to estimate the phase polynomial coefficients for short sequence PPSs. A highorder ambiguity function and product highorder ambiguity function based PPS parameter estimation algorithm was introduced. By analyzing its performance especially in the case of the short sequence, the improvement to this algorithm was made. The MonteCarlo simulation shows that the proposed algorithm improves the estimation effect and raises the operation efficiency.

The traditional TCP congestion control algorithm is unsuitable for the multimedia traffics because of the fact that when a packet is discarded, the sender halves its rate, resulting in sending rate wobbling greatly. An enhanced congestion control algorithm, slow increase slow decrease(SISD), was propored based on the algorithm additive increase multiplicative decrease(AIMD). The simulation results show that SISD algorithm has better smoothness of sending rate compared with the congestion control algorithm of TCP, which reduces the fluctuation of sending data and adds the congestion control to multimedia traffics. This algorithm can act as development basis of realtime multimedia traffics, and improve the transmission quality of TCP traffics.

High hydrostatic pressure extraction (HHPE) technique was used to extract flavonoids from Hawthorn leaves at normal temperature. The content of flavonoids was determined by UVspectrophotometry. Parameters that may influence the extraction process were investigated. Orthogonal test was applied to obtain the optimum extraction condition, which was as follows: solid dissolved in 50% ethanol, ratio of raw Hawthorn leaves (g) to solvent (ml) of 1∶45, temperature of 60 ℃, extraction pressure of 400 MPa and extraction time of 3 min. Results of this work show that HHPE possesses several advantages over other extraction methods, such as higher efficiency, shorter extraction time, and less impurity in the extracted flavonoids.

Near infrared diffuse reflectance spectroscopy with partial least square fitting (NIRSPLS) was applied for nondestructive quantification of the content of Pyrazinamide in Pyrazinamide tablets. A mathematical calibration model of NIRS was proposed using the first derivative spectrum in the wavelength range from 800 to 1200 nm. For this model, the regression coefficient (R) between predicted values and actual values in calibration set is as high as 0.9989 and the root meansquare error of prediction (RMSEP) is 0.563. Results show that this model is reliable with high prediction accuracy and is convenient for use, that can be used as general means in pharmaceutical analysis.