Abstract:In order to reduce development time and cost of dualclutch automated mechanical transmission(DCT) control system,the dynamic model of automobile DCT control system is established by Matlab/SimDriveLine and the engine model is improved by neural network.Based on Matlab/Simulink,the simulation models of DCT control during starting phase,shift phase and shift rule are set up,and then the whole system of DCT is simulated.The simulation result indicates that the DCT system dynamic model and the designed controller are reasonable and feasible,and proofs that the model is suitable for developing DCT control system and improves the design efficiency of DCT system.

Abstract:Belt grinding machine with multiaxis computer number control(CNC) system can effectively process parts with complex moulding surfaces.In this paper,isoparametric and isoplanar tool path planning strategies customized for this kind of machine are proposed.The tool path generation methods are designed based on the analysis of the belt grinding process.By using least square method,optimized cross section normal is computed in the isoplanar method.To improve the design efficiency of path planning,reduce experiments and increase economical benefit,the geometric simulation program based on linear grinding model is developed.Experiment on a turbine blade profile shows that the proposed algorithms work satisfyingly.

Abstract:It is proposed to introduce approximate model method to crashworthiness optimization design of thinwall beam,and the approximate model can be optimized by using sequential response surface method.In order to solve the parameterization design problem of finite element model,a parameterization model about material,crosssection size and spotweld of thinwall beam is established by developing corresponding procedures.The results show that optimization design can not only improve the performance of absorbing energy of thinwall beam,but also reduce the weight greatly;the approximate model method can greatly improve optimization efficiency.

Abstract:Abrasive belt grinding experiments of glass fiber reinforced plastics composite material are carried out by using three different abrasive belts with different sizes,and the interaction principle between the abrasive and the workpiece is analyzed.The main factors of material removal rate and belt life of glass fiber reinforced plastics composite material are obtained through a large number of tests and test data.The extent and the main reason of belt plug are analyzed through the professional image analysis software (ImagePro Plus) for the first time.The results show that in the process of abrasive belt grinding,the material removal rate are affected by the factors for grinding pressure,belt speed,abrasive type and size,and the ceramic abrasive belt has the highest removal rate.The main factor for belt plug extent is grinding pressure.The most important wear form of abrasive belt is blunt,and the accumulation abrasive belt has the longest life,followed by ceramic abrasive belt.

Abstract:CT25 special friction welding machine is used to weld 35CrMnSi/T3 with different inertial flywheel rotation speeds.The interface microcosmic binding characteristics and microstructure changes are observed by SEM.The element diffusion near the interface is detected by EDS and the microhardness of plastic deformation zone in Cu matrix is tested.The results show that,when the inertial flywheel rotation speed increases,friction heat of primary pressure increases significantly,more plastic deformation forms between the contact surfaces by secondary pressure,and bonding of work pieces is promoted.When the flywheel rotation speed is 3 000 r/min,the joint of 35CrMnSi/T3 by inertial radial friction welding process gets clean binding domain,elements obviously diffuses,the finegrain αFe and εCu structure forms in recrystallization zone and the welding effect is good.The microhardness of interface region in Cu matrix is increased by violent plastic deformation.

Abstract:The working principle and the valve train characteristics of the developed variable damping shock absorber are analyzed.According to the hydromechanics theory,a mathematical model of the variabledamping shock absorber is established through MATLAB and the calculation formula is deduced.The FS curve and FV curve are obtained through computer simulation.According to QC/T545 national standard,external characteristic curve is obtained by bench test.The simulation result is compared with the experimental data and the correctness of the mathematical model is proved.The model accurately describes the variation of damping force with the displacement and can be used for shock absorber design and performance prediction.

Abstract:The USBCAN bus converter is a connector of USB bus and CAN bus.It is difficult to judge whether the device works well or not and meets design requirement or not by ordinary ways.Regarded the Matlab/Simulink/Stateflow toolbox as the platform,the model of a USBCAN bus converter is established.The model of the bus converter is tested and verified in the Matlab/Simulink simulation environment.The results of the simulation analysis show the model is suitable for simulating the working state of the device.A new simulation and judging method for bus converters is proposed.

Abstract:A novel scheme based on voltage prediction and fast virtual vector modulation algorithm for direct torque control of a permanent magnet synchronous motor fed by diode clamped multilevel inverter is proposed.The system is based on diode clamped threelevel inverter,which is widely applied to middlehigh voltage speed regulation.Combined with space vector modulation,the reference voltage vector for direct torque control is obtained by voltage predictive control algorithm,then zero vector and two adjacent virtual vectors are used to synthesize reference voltage vector based on nonorthogonal 60° coordinate.The neutral point potential is controlled by using the neutralpoint current characteristics of small vectors,the desired basic voltages and their dwelling time can be easily obtained and fast space vector modulation is achieved.Simulation results verify the feasibility of the proposed control scheme,that dv/dt of output voltage and neutralpoint potential of threelevel inverter are restrained effectively,and high dynamic and steady performances are obtained.

Abstract:To accurately analyze the loss and heat of large hydrogenerator,the finite element models of 2D steadystate electromagnetic field,moving electromagnetic field and fieldcircuit coupling are established respectively.As an example,the losses of the rotor iron and damper winding of a 36 MW tubular hydrogenerator are calculated.Furthermore,the influences of 3 different electromagnetic field models on the thermal sources and temperatures are analyzed by 3D finite element calculation of the temperature field.The results are compared with the test data and indicate that the precision of the fieldcircuit coupling model is better.The losses of each damp bar are different and the heat of the damp bar at the lee side is larger than that at the windward with the full load.The maximal temperature of the rotor is located at the damper winding,instead of the field winding.The research is valuable for improving the calculation precision of the rotor losses and temperature field and enhancing the reliability of the hydrogenerator design and operation.

Abstract:It is studied how to charge the battery of the implanted medical device through the skin according to its bioelectrical characteristics.Energy delivery model of volume conduction is created by FEMlab 3.3 (Finite Element Model Lab),using AC voltage as the input.In simulation,the frequency characteristic of the model is tested,and then 4 different shapes of electrodes are designed.Taking cylindrical electrode for example,the shape and layout of electrode are optimized by changing the electrodes’ crosssection areas and the distance between the electrodes.According to the simulation results,current transmitting efficiency can reach above 30% under the premise of ensuring human security.

Abstract:Environmental/Economic Power Dispatch (EED) now is one of the critical issues in power systems.Aiming at the nonlinear fuel cost function and particle emission function which take generation unit’s real power generation amount as decision variable,the generation unit is transformed into a fuzzy variable and a novel fuzzy multiobjects model for EED is proposed to replace the traditional quadratic programming model.Furthermore,an improved genetic algorithm is adopted to find out the optimal solutions.Finally,the effectiveness of the method is testified by the simulations on an IEEE 3generator test system,and the result shows the cost of power system and particle emission amount are greatly reduced.

Abstract:Aiming at the problem of low excavation speed and high risk of coal and gas outburst because of low gas draining rate in heading excavation,and taking an excavation heading of a mine for example,the test of deephole presplitting blasting is processed.The amount of gas draining after presplitting is compared with the amount of direct draining,and the effective radius of draining is surveyed.The test result shows that the draining rate of K1 coal seam reaches 37.13 %,which reduces the draining time by 60%,10 days after presplitting,and the gas desorption index exceeds the standards until the fifth blasting.The draining rate of K4 needs 12 days to reach 34.28 %,which reduces the draining time by 60%,and the gas desorption index exceeds the standards when the third blasting processes.Obviously,the effect of gas draining is improved by presplitting blasting.The effective draining radius of K1 and K4 are 4.5 and 5.2 m respectively after presplitting blasting.The research can provide reference for the fieldwork of presplitting blasting.

Abstract:Three kinds of coal samples with different components are chosen as study objects.Density calculation and SEM are adopted to study their internal structures,and a selfmade triaxial gas seepage instrument is used to study their internal gas flow characteristics.The results show that internal structures of coal samples made of different particle size coal powders under identical external conditions are various,and nonlinearity is presented on the influence caused by fabric.Gas flow characteristic is complex in complete stressstrain process,generally it firstly increases and then decreases,initial gas flow velocity is lower than the one after the failure of coal sample,and obvious hysteretic nature of gas flow characteristic is showed.The influence of gas flow characteristic caused by initialinternal structure of coal sample is nonlinear and the stresssensitivity is high on the influence of gas flow characteristic caused by initialinternal structure.The more complex the initialinternal structure of the coal sample is,the lower the axial tresssensitivity is,and the higher the confining pressuresensitivity is.

Abstract:Nitrobenzene compounds,featured with weak mutagenicity,chemical stability,are difficult to be purified by traditional degradation method.Several factors involved in the nitrobenzene wastewater degradation are comparatively analyzed by cavitating water jets assisted with Fenton.The removal ratio of nitrobenzene,whose concentration is 50 mg/L,reaches 95.06% when the Fe2+ concentration is 40 mg/L,the pH value,5.0,the hydrogen peroxide concentration,150 mg/L,the confining pressure,0.5 MPa,and the jetting pressure,10 MPa.The degradation mechanism,shown by high performance liquid chromatography (HPLC),is that the cavitating water jet impelled the Fenton to release more HO· and enhances the catalytic capacity of Fe2+,then the nitrobenzene is degraded or oxidized totally,or graded into small organic molecules such as chain hydrocarbon and organic acids,etc.Besides,the intermediate products,including Benzoquinone,4Nitrophenol,2Nitrophenol and Hydroquinone,are also shown by HPLC.

Abstract:Not only population densities of phytoplankton but also its community structure can be influenced by nitrite concentration.To investigate this effect,the growth and competition of Microcystis aeruginosa and Scendesmus quadricauda under different nitrite concentrations are studied by using batch cultures,and the competition relation is analyzed by the competition parameters.The results indicate that there is competition between M.aeruginosa and S.quadricauda in present experiment conditions,and S.quadricauda is dominant in competition.Meanwhile,the increase of nitrite concentration can strengthen S.quadricauda dominance,because under high nitrite concentration (20 mg/L,30 mg/L),M.aeruginosa is more damaged and the allelopathy between M.aeruginosa and S.quadricauda is intenser.

Abstract:Taking into account many influence factors of ground subsidence induced by underground exploitation,based on partial leastsquares multinomial regression,a forecast analysis on the maximum of ground subsidence is carried out.Taking height,depth,obliquity of coal clay and rigidity coefficient as independent variables,and maximum of ground subsidence as dependent variable,the forecast model of maximum of ground subsidence is obtained.It is found that,Press residual value decreases with the increase of number of latent variables,and the number of latent variables is four by Press residual value versus number of latent variables.The normal regression coefficient of height is the largest in the four influence factors,and this indicates that the influence of height is the largest on maximum of ground subsidence.The determination coefficient of forecast model obtained in this paper is 0.915 7,the error of forecast model is ±10.41%.The following conclusion can be drawn that the model based on partial leastsquares multinomial regression is a better and feasible nonlinear method.

Abstract:Based on the landslide control scheme optimized by considering technical index and other factors,a landslide comprehensive control thought of “treating scheme optimization combined monitoring information feedback” is put forward.The multilevel hierarchical comprehensive evaluation index on landslide control scheme is set up on the basis of analyzing many engineering examples,and formula of weight,fuzzy complementary judgment matrix and the consistency check method of judgment matrix of fuzzy analytical hierarchy process are given,the solution of multiobjective decision problems based on improved fuzzy analytical hierarchy process is developed,too.Validity and reliability of this method is proved through the scheme selection for Xiangjiapo landslide control.It provides an effective method for construction decision makers.

Abstract:Production of high strength steel bumper can greatly enhance the occupant safety.However,it is very hard to form high strength steel plate.There is rare domestic successful reference.The hot stamping technology aboard increases costs significantly,and the efficiency is low.Therefore,the only solution is combining advanced numerical simulation technology with current adjusting stamping process.The coldforming process of a sedan’s high strength steel bumper is simulated by FEM software Dynaform and the results show that springback and crack are the main defects.A law is summed up by researching the influence of different shapes of addendums on part forming and springback.Finally,the optimized shape of addendum is obtained by adjusting the addendum and adding convex roofs.It provides references for manufacturing similar high strength steel parts.

Abstract:According to the low voltage power line channel features,combined with adaptive bit loading and power allocation algorithm,an optimal equivalent subchannel algorithm is proposed.Under the condition of fixed amount of transmitted bits and the minimum transmitted power model,impact of optimal equivalent subchannel on the system performance is studied.The optimization algorithm sorts subchannels with similar transmission features into groups,thus the signaling load can be reduced,and the spectrum can be better used.The simulation results show that system can get lower bit error rate(BER) by adopting optimal equivalent subchannel algorithm.

Abstract:For making the refrigeration system directly driven by low temperature waste flue gas heat more efficiently,an experimental research on the heat transfer of vertical intube laminar falling film with different heat fluxes and different concentrations of lithium bromide solution is conducted.The outcome of falling film evaporation experiments show that the heat transfer coefficient increases with the decrease of inlet concentration of lithium bromide solution and significantly increases with the increase of heat flux.Based on multiple linear regression calculation of experimental data,an experimental correlation of falling film heat transfer coefficient is obtained.A falling film generator of lithium bromide absorption chiller is designed from the correlation,and the immersed generator whose heat load is equal to the falling film generator is designed.The comparison of the two generators on heat transfer coefficient,weight and volume of heat transfer components shows that the falling film generator has great advantages.

Abstract:Anisotropic conductive adhesive film(ACF) is chosen to substitute for Sn/Pb solder and applied to microelectronic packaging.In this thesis,ACF is composed of polystyrene microspheres(PSt)(3~5 μm) plated with a thin Ni particles(1~2 μm) outside and a special epoxy resin.Both of them are mixed to be ACF.Electronic conductive attributes and corrosive resistance behavior of ACF are analyzed by alternating current impedance measurement and potentiodynamic polarization under highly thermal humid conditions.The results show that after aging 4 h in 80 ℃ and 85% RH condition,contact resistance of ACF increases greatly,and the main reason is the oxidation formation of Ni prevents electric current from going through.Furthermore,the effect of temperature on corrosive behavior of ACF exceeds the effect of humidity,and both of them accelerate the failure of ACF reliability in microelectronic interconnection.Corrosion resistances of ACF are better than that of Sn37Pb solder in the same case.The possible reason is that Ni is protected by the base epoxy resin,and dispersion of corrosive medium into adhesive interlayer is held back.

Abstract:Through GIS spatial analysis and entropy calculation,the ecoenvironmental quality of highway is studied.By use of pressurestateresponse model and expert advice method,the highway environment evaluation indexes are determined.The indexes are treated with dimensionless method.On the basis of entropy theory,the weight of evaluation indexes is calculated.Then,the ecoenvironmental quality evaluation model of highway is set up.Finally,supported by the RS and GIS,the status of ecological environment of a highway in Qinghai Province is analyzed.Using MATLAB tools,the entropy of each index’s value and the entropy weight are calculated,and the ecological environment quality of the highway is researched by using the ecoenvironmental quality evaluation model.

Abstract:Iceshedding on transmission lines results in longitudinal unbalanced forces on adjacent transmission towers,which significantly threaten the safety of transmission lines.The methodology of iceshedding simulation on transmission lines is developed by using the finite element method and validated by comparing the simulation results with those obtained from the modelscale experiments done by previous researchers.The responses of the towerline system induced by simultaneous iceshedding on the conductor and ground wire are analyzed.The developed methodology is then applied to study iceshedding considering unzipping effect,in which the influence of the velocity of iceshedding on the responses is investigated.Results from this study show that the longitudinal unbalanced forces induced by simultaneous iceshedding from the ground wire are greater than those from the conductor under similar condition.During the analysis of iceshedding considering unzipping effect,the slower the velocity of iceshedding is,the closer the responses are to those resulting from static unloading;and the faster the velocity of iceshedding is,the closer the responses are to those resulting from simultaneous iceshedding.