A thermodynamic analysis on in-situ TiC synthesis in Fe-C-Ti-Mn system was made on the basis of solution thermodynamics theory. Calculated results show that the formation of TiC is ahead of the formation of Fe₃C and Fe₂Ti and TiC is more stable than Fe₃C and Fe₂Ti thermodynamically. Usually, TiC is formed before the solidification of matrix alloy while Fe₃C and Fe₂Ti are separated during the solidification and cooling process of the alloy. With the increase of C concentration, the possibility of TiC and Fe₃C formation are increased.Furthermore,with higher Ti concentration, the possibility of Fe₂Ti and Fe₃C formation are increased and decreased, respectively. The formation of TiC is promoted when the concentration of C and Ti are higher and that of Fe₂Ti is promoted when Ti concentration is higher and C concentration is lower.Moreover, the formation of Fe₃C is prompted when C concentration is higher and Ti concentration is lower.By addition of appropriate amount of Mn, the formation of Fe₃C is inhibited effectively and the TiC synthesis temperature reduces significantly,so that most of TiC synthesis reaction will take place in the alloy solidification and cooling process after the molten alloy fills up the cast form,thus it is possible to solve the problem of too early separation of TiC and form filling difficulty due to increase of molten alloy viscosity.

The profiles surfaces processed by cryogenic polishing without abrasive were obtained by HL-Ⅱ microprocessor controlled atom force microscope and the influences of various processing parameters on the fractal dimension D and the arithmetical mean deviation of profile Ra were investigated. The results show that the D and Ra represent the different aspects of the surface, they correlate each other but do not have linear relationship. For the same working method, the D of hard alloy component surface is bigger than that of aluminum alloy component surface. The fractal dimension may reveal the supersmooth surface quality.

A method for threshold selection and decision to obtain noise characteristics in VLSI circuits was presented.This method by using multiresolution signal decomposition noise model made the analysis of system parameters easy and accurate.Simulation results show that non-stationary noise can be identified in time domain and resolution improvement is obvious compared with that of conventional noise detection in frequency domain.And in particular,real time non-stationary noise detection in wavelet domain possesses strong adaptability,needs less priori information,realizes complete reconstruction,keeps waveform information of the original signals,and improves SNR,etc.This study offers a theoretical basis and noise detection method for VLSI circuit components selection,faults diagnosis and localization,and reliability analysis.

A continuous predictive model based on time sequence theory and the connatural characteristic of CDMA was presented. According to the unsteady time sequence access feature of CDMA cell, a predictive mode depending on mutually complementary historical data and sampled data was established by this model.In order to improve the convergence of the model the sampled data was smoothed according to the extremum made by the partial differential equation.Through the full consideration of the periodic,random and bursting properties in operation of CDMA network, the model had got good performance in self-adaption and could eliminated the influence of the burst data to a certain extent.The model has the ability of predicting the network load accurately for a certain period of time,so the QoS parameters can be adjusted in advance,and hence avoid the dithering of the sysem and enhance the successful access rate.Experiment results show that this model can increase effectively the QoS performance of the CDMA network with smaller calculating cost.

An equivalent linear damping for ER fluid's nonlinear damping was made by means of equivalent linearization,and the influence of variable damping of ER fluid on system vibration properties were analysed.The nonlinear equation of the vibrtion response of ER damper has been calculated.The results show that ER fluid could obviously reduce the vibration amplitudes of system.The damping of the system can be controled by controling the intensity of electric field.With the increase of intensity of electric field,the frequency peak value increases and the peak value of resonance decreases.

Modal optimal control of intelligent inner noise control was studied. Modal controller design method was given based on the modal optimal control equation. A rectangular box structure consisting of beams and laminate shell was presented to illuminate the effect of control. The noise pressure responses of the uncontrolled and controlled systems were obtained. The numerical results show that the inner noise can be reduced from 94.32 dB of the uncontrolled system to 87.27 dB by using the present intelligent control method.

Dislocation densities in 20CrMnTi steel under different sizes of strain were determined exactly by X-ray diffraction method and a new profile analysis theory. The relation of strain and dislocation densities was analyzed. The results show that the increase of dislocation density is accompanied by the increase of deformation amount. The dislocation density has lower value when the steel is annealed. TEM tests prove that 20CrMnTi become ferrite and pearlite after annealing. Intragranular dislocation appears as zigzag dislocation line and comes into being cell structure with the appearance of twin crystals after deformation. Cell structure improves the strength of steel greatly.

On the basis of the fit for autocorrelation function,a new SNR estimation approach for 1/ƒ fractal signal was proposed.The total delay time could be determined through the time of mutual information curve of the signal with noise getting to the maximum in the first quadrant.Simulation results show that this method is simple,reliable,practicable,and effective without awareness of fractal signal parameters and a priori knowledge of added white noise,which means it is suitable in most situations.

A new digital watermarking algorithm based on the studies of different watermarking and digital signal processing methods was proposed.In this algorithm,watermark embedded in image was constructed by several harmonics with known frequencies.To detect the similarity between the original watermark and the watermark extracted from the watermarked image,harmonics frequency estimations were conducted.Simulation results show that this algorithm can deal with complicated additive noise,resist cropping,JPEG compression,and Gaussian-like noise pollution,and it is robust.Hence it is proved that harmonic retrieval method could be applied in digital watermarking technology.

An approach of iris identification based on real Gabor transform (RGT) was proposed. The localization property in time-frequency domain of RGT was suitable for extracting features of iris texture. Based on the theory of linear algebra the dual window function of Gaussian function was computed. The RGT of the dual window function is employed to analysis the normalized iris texture. The mean and variance were computed and formed in array to represent the features of iris texture. This algorithm was completed by real computation. A significant computation effort of RGT can be saved. The experiment results and data analysis are given to illnstrate the effectiveness of the prent mothod.

Based on the research of some recent algorithms of the initial solution guess work of one step forming, an improvecd algorithm based on the geometry expanding, section curve expanding method was presented. This algorithm has the merits of geometry expanding method and overcomes the difficulty for searching symmetry curve confronted by the "Geometric Mapping" method. So it enabled the one step forming method more practical. The computer program was also developed. The comparison of the simulation results of flower-shaped cup with experimental data shows that the initial blank shape obtained by one step method quite agres with those obtained by the experiment and verifies the effectiveness of the present method.

Characters of resistant spot welding case were divided into two categories,i.e.,case characters Ⅰ and case characters Ⅱ by analyzing the process in the light of attributes of case based reasoning (CBR).The following retrieval strategy from similar spot welding cases for aluminum alloys was proposed:under the restraint of case characters Ⅰ,the thermal physical properties of material and the plate thickness involved in case character Ⅱ were taken as indexes to retrieve the similar cases.The technological knowledge and rules drawn and summarized from the corresponding similar cases database by means of fuzzy inference were used to guide the solution of the new case.It is a good approach to deal with the problem that in the design of spot welding process for aluminum alloys,it is difficult to build an appropriate model to revise the retrieved similar case on CBR.The proposed intelligent choice of the spot welding parameters bears a more resemblance to the thinking mode of experts in this field.The choice process is flexible and open to environment.Application instances of the system and technological verification show that the developed approach is practicable.

On the base of magnesium alloy AZ91 matrix the composites reinforced with graphite particles（Gr_p） and alumina short fibers(Al₂O_3f) were fabricated with squeeze casting method.The microstructure and mechanical properties were investigated.The friction and wear characteristics were also studied.The experimental results show that the reinforcement phase dispersed evenly and closely bonded with the matrix.The hardness of the composites decreases with increasing Gr_p volume fraction,addition of Al₂O_3fincreases the hardness of the composites.The tensile strength and fracture elongation of the composites decreases with the increasing content of Gr_p.The tribological behaviors are improved with the increase of Gr_p content,both the wear rate and friction coefficient reduce.A continuous black lubricating film forms gradually on the sample surface with the friction process.

A fuel economy model was set up for the engine and on its basis the matching strategy for continuously variable transmission with the engine was studied and the relationship between engine goal rpm and vehicle speed was determined.The comprehensive control strategy was formulated from the demand on vehicle dynamic performance at transient operating conditions and fuel economy at steady operating conditions.The improved comprehensive control strategy remedies the deficiency of control strategy for best fuel economy,improves the vehicle dynamic performance at transient conditions without penalty on steady condition fuel economy.

A shock absorber controller of damping-adjustable semi-active suspension was developed for the CA6440 light-duty bus.A test device for the controller has been established by which the hardware and software were studied.Results show that the developed controller is practical and reliable.

A simplified dynamic model on four wheel drive vehicle was established. The PI control and fuzzy control were used to design engine fuzzy PI throttle controller and lookup tables were given.A simulation of four wheel drive vehicle traction control on sand pool was made. The results show that the engine throttle controller established by the above-mentioned control methods can avoid excessive spin of driving wheel and keep the slip rate between tire and sand in optimum state with good traction performance.

Several types of friction pair with ordinary and bionic structure from material of piston aluminium alloy and cylinder liner cast iron were designed based on the bionic principles and comparative tests of these pairs were done on a friction and wear machine.The resulls show that under dry friction condition there are little difference of tribological behavior between pairs with ordinary and bionic structure.But under the condition of splash lubrication,the anti-sticking wear resistance of the bionically unsmoothed surface is better than that of ordinary surface.The reason is that the bionically unsmoothed surface has better ability on lube storage and oil film forming.

The fracture-splitting mechanism and conditions were discussed and the key techniques and working procedures such as the material selection, machining of cracking notches, directed fracture separating and assembling bolts in required torque were presented. A fracture-splitting machine that can provide backpressure in cap of connecting rod was developed and fracture-splitting processing for car engine connecting rods was investigated numerically and experimentally. The results show that the right design in notch location and geometry and the satisfactory precision for notching reduces fracture loads effectively, the backpressure is of benefit to splitting quality, a right ratio of splitting force to backpressure force brings a perfect fracture face in the case of applying instantaneous load to hole in the big end of connecting rod.

The formation of the defective dimple and its influencing factors in multi-point forming(MPF) process of sheet metal were analysed mechanically and it was indicated that dimpling defect could be eliminated evidently with elastic cushion.In the forming processes of MPF press and multi-step MPF,the restraint condition and deformation path of sheet metal were changed,and the forming defects were subdued,then the forming limitation was improved and large deformation could be achieved.Numerical results and forming tests of typical specimens demonstrate that dimples are eliminated effectively by means of elastic cushion and multi-step MPF.

Based on the energy principles and the limit method in plastic theory in the light of metal flow pattern and displacement-velocity model of metal deformation in flashnless die forging,the forces acted on the punch in this kind of forging was analysed.The relationship between the force acted on the punch and cone angle of the punch was derived and the cone angle of the punch was optimized.It is the result that optimum punch taper is an angle of 15?.The research results were used in design of a punch in flashless die forging for the star-like inner race of constant-velocity universal joint in cars and the fracture problem of punch was solved.

A simple algorithm to the particular structure of hydraulic servo manipulator was introduced based on the relation of line to line and line to plane to deal with real time collision detection between graphic robot and operation task in consideration of the bounding volume hierarchy method.Validity of this algorithm was proved through experiments.The experimental results show that the proposed collision detection model is simple and fast in calculation,and easy for realization.It can solve on line simulation problem in remote operation for construction robot,and could be applied in simple virtual reality system.

In ground source heat pump (GSHP) of geothermal energy utilization system,a concept of intermittent process (GSHP on or off) was proposed to restore underground temperature and compensate insufficient soil and rock heat transfer.The intermittence helps full diffusion of terrestrial heat to promote temperature uniformity and boost underground heat transfer load.Thereby,the number of heat transfer well in GSHP system can be minimized because of better working condition of GSHP.

Without configuration modification of a turbo-charged after-cooled direct injection diesel engine, two kinds of diesohol fuel (E10 and E15) were used to study their effect on engine performance, fuel economy and exhaust emission. The results show that the power output of engine decreases while the brake specific fuel consumption (bsfc) increases. The brake specific energy consumption (bsec) using diesohol increases at the low load and is equivalent at the mid-to-high load range in comparison with that of the diesel fuel.The engine emission performance shows that CO emission and the smoke emission decrease obviously, HC emission increases gradually, especially at the low load, and NO_x emission decreases at the low load and low speed conditions while is equivalent at the high speed. The tests according to ECE R49 13-mode indicate that many brake specific emissions increase. The major reason is that the contributions of low load conditions increase. This study will provide the basis for the next study, putting emphasis on the low load conditions.

A new approach utilizing dynamic traffic simulation was proposed to assess the traffic environment based on the two current international evaluation methods,i.e., traffic management and static traffic simulation was proposed. The traffic emission evaluation system framework consists of four modules for traffic network, traffic demand, traffic simulation and automotive emission.The approach could real-time describe the automotive dynamic movement behavior in the traffic network accurately, therefore, evaluate accurately the transportation environment of city-wide modern traffic network and assess the environmental impacts of the particular intelligent transportation system.

The traffic sensor data screening of intelligent transportation system(ITS) was discussed and the data flow exchange between data screening unit and other system of Traffic Information Center(TIC) was described.The content and general procedure of data screening were introduced.The checking condition of data reasonableness and consistency in different traffic conditions were analysized.Data screening can identify the error data from the raw sensor data,and assure the reliability of input information to traffic related functions.

The surface modification of 45^# steel bombarded by high-current pulsed electron beam was studied and microstructure and surface modification were analysed and discussed. Experimental results show that microstructure of near-surface layers can be divided into four zones along the direction of electric beam: the white layer or melted layer (3～10μm), the heat effecting zone (10～50μm), stress effecting zone (50～250μm) and matrix (after 250μm).The microhardness increases with increasing of bombardment times,abrasion resistance property is enhanced by increasing of the bombardment times.

A reliability selectionmethod for astronautic optoelectronic coupled devices(OCD) by using low frequency noise measuring was presented.Based on large amount of measurement for OCD,with Levenberg-Marquardt algoritm,the fit for real curve of low frequency noise spectrum parameters was conducted in order to detect defects leading to the noise increase in the devices.Practical application for OCD selection proved that this method is valid and fast,and can provide a theoretical foundation to improve OCD production techniques,qualities,and reliabilities.

A communication system between transmission control unit(TCU) of automated mechanical transmission(AMT) and engine control unit(ECU) was developed by means of controller area network(CAN).The CAN design concepts and the communication process between TCU and ECU were described.The experiment was implemented on a Santana 2000 car.The test results show that the developed system coordinates the control between engine and the clutch.The noise of engine during gear shift process is reduced effectively.The shift time is shortened.The working smoothness of the clutch is improved and the cost of AMT is reduced.

With the increasing of equipment fault complexity,traditional expert system fault diagnosis methods can not provide accurate decision.In order to solve the problems in power plant equipment fault diagnosis,a method by the combination of fuzzy theory on the basis of information fusion and expert system was proposed.This method with multi-sensors can monitor power plant equipment on line.Lower error and omission diagnosis ratios,and higher correct diagnosis ratio are obtained by using this method compared to the conventional methods when it was applied in Fengman hydropower plant digital simulation system.The simulation results show that this method is easy,realizable,general,and practical in the power plant equipment fault diagnosis.

With the development of price management subsystem of the group enterprise the concept of longitudinal synthesized structure of management system was described,the characteristics of longitudinal synthesized structure and together with the Client/Server mode, Browser/Server mode, mixed mode were analyzed;and accordingly the design thought and method for this structure based on the mixed mode of (C/S and B/S were presented.)The management subsystem with 3-tiers longitudinal synthesized structure by using PB and ASP combining with the technique of WEB and database had been developed.

In order to obtain the complete and real mechanics characteristic curve of rock, the rock mechanics testing system controlled by the microcomputer, electro-hydraulic servo control, was studied, which is based on the traditional mechanics test. The timing, trigger, and A/D conversion of the syetem are completed by multi-functional panel PC812PG, and the CPU control is not needed. The panel PC812PG sampling runs at the same time of CPU, which saves the of time CPU. The computer system has high efficiency, and avails to improve the frequency response of control system. The application and debugging of the rock testing system indicates that the system can be controlled exactly and smoothly, and the results of the experiment is reliable.

Based on the requirement of ISO/DIS9000 international standard,the customer satisfaction of numerically controlled (NC) machine tool was studied.Considering the peculiar conditions of domestic manufacturers of NC machine tools,the customer satisfaction evaluating system was set up for the first time to analyze the data quantitatively,quantifying the customer psychological state towards satisfaction.The hierarchy analysis process was applied to determine the weight of each assessment index,fuzzy comprehensive evaluation method was used to process the customer satisfaction index of NC machine tool.For a certain type of machine tool,the deficiency was revealed through the calculation of customer satisfaction index,therefore,charting the course for improving the product and service quality of NC machine tools.

An edible film which instantly dissolves in the hot water was developed on the base of soy protein isolate and carboxy methyl cellulose was added as the intensifier and glycerol as the plasticizer.The optimization experiments were performed by means of the orthogonalizing test plan.The results of variance analyses show that the most significant factor for the tensile strength and fracture elongation is the volume fraction of glycerol while that for the instant dissolving rate in the hot water is the drying temperature of the film.The optimized process and formula are obtained for the best instant dissolving rate in the hot water:the drying temperature is 50℃,the mass fraction of soy protein isolate is 4.5%,the mass fraction of carboxy methly cellulose is 0.7%,and the volume fraction of glycerol is 1.0%.

There are three layers in the whole structure of the core competitory competence and there is a core in every layer, which are valuable to evaluate the core competitory competence of the enterprise. On the base of the structure of the core competitory competence, the evaluation ideas were suggested, and the evaluation index system of the core competitory competence was designed. Then the methodological system for evaluation was constructed in respect of the evaluation process, the measure of the evaluation indexes and the comprehensive evaluation method of the core competitory competence.