Abstract:Determining the contact area and the distributing law of contact force is the key to the calculation of the laminated beam. In this paper, the contact problem of laminated beam was constructed into a linear complementarity model so as to overcome some irrational conclusions of traditional analytical solution. Then, the general solving process of the proposed method was obtained. And its rationlity was verified by recalculating the contact problem of beam with the rigid body discussed by Timoshenko and Hu Haichang. On this basis, the contact law of laminated beam underlying typical loads was investigated and the factors influencing the law were studied. Finally, some conclusions were obtained. All the factors such as the stiffness ratio of laminated beam, load form and shear deformation affected the contact law noticeably. When taking into account the shear deformation in computing the laminated beam, the contact force was in the form of distributing force, or it was a concentrated force when considering no shear deformation. The contact law of laminated beam tended to be point contact under concentrated force and it was in line contact under distributing loads. The same degree of rigidity of the laminated beam was the turning point of contact press distribution. Different stiffness ratios of the laminated beam had different contact laws.

Abstract:A new inflow turbulence generator called discretizing and synthesizing random flow generation was applied to simulate the actual boundary conditions of turbulent flow field. A new oneequation dynamic subgrid scale (SGS) model was adopted for the large eddy simulations. The wind loads on the roof of Changsha Airport Extension Building with five wind directions were calculated on the basis of the paralleled technology of Fluent6.3 soft platform under the linux system. The distribution characteristics of the surface wind pressure on the roof and the most unfavorable wind direction were determined by analyzing the mean and fluctuating pressure coefficient contours. The results are valuable for the windresistant design of Changsha Airport Extension Building and provide useful information for the numerical simulation of wind loads of other similar structures. The results show that the response trends are the same and the response is close, though different methods were used to simulate water body and different analysis methods were employed.

Abstract:The variable of multisupport excitation effect, which is extracted from the analytical formulae of the power spectrum density function (PSDF) of seismic response of a 2mass with 2support simplified system, was proposed to study the variation of the random seismic response due to the wave passage effect and incoherence effect. And a numerical example of a gatetype truss structure was given to validate the practicability of the results gained from the simplified system. It is shown that the quasistatic response will increase while considering the wave passage effect or incoherence effect; the relative dynamic response fluctuates with the increase of wave passage frequency, and the extreme point's distribution is determined by the ratio of natural vibration frequency to wave passage frequency; and the incoherence effect will not change the extreme points' distribution, but reduce the fluctuation amplitude. For actual structures, more wave velocities are proposed to be employed to obtain reliable results, since they have a strong influence on the seismic response. The incoherence effect has little influence on the actual structures, especially when the structure's span is small.

Abstract:It is of significant practical value to investigate the strength variation of unsaturated residual soil with different water contents, and establish the computational formulae between them. In the general triaxial instrument, strength tests were conducted on unsaturated residual soil. The results indicated that the shear strength of unsaturated residual soil decreased significantly with the increase of the water content, which demonstrated that water contents had considerable influence on strength. Quantitative analysis of the strain softening characteristics of unsaturated residual soil was done by adopting peakresidual stress ratio. It was found that the optimum water content equaled the critical water content where stressstrain curve was transformed from softening to hardening, the value of c decayed exponentially with the increase of water content, and the value of φ decayed linearly. Based on these results, the integral stress strength formula of unsaturated residual soil was proposed, which can be applied in practice and provide reference in practical situations.

Abstract:A dynamic model of the work process of a new type rotating ball valve with double direction metal sealing was established. And the dynamic model was simulated and analyzed by using Gear PredictorCorrector Algorithm. The results of dynamic simulation and analysis revealed that the torsion of turning on the new type rotating ball valve was less than the torsion of closing up the new type rotating ball valve. And in order to avoid water hammer, the torsion of turning on the new type rotating ball valve should be less than or equal to 5 500 N·m, and the torsion of closing up the new type rotating ball valve should be less than or equal to 4 650 N·m, when the velocity of flowing water was 5 m/s.

Abstract:According to the nonlinear theory, the bifurcation characteristics of front wheel selfexcited shimmy of some motor vehicle with nonindependent suspension were studied. Computer programs were carried out to calculate the range of selfexcited shimmy speed of the motor vehicle with MATLAB when Hopf bifurcation took place. Various bifurcation diagrams indicating the relationship between angle amplitudes of right tire and vehicle speed were presented. And the influences of different parameters on selfexcited shimmy were analyzed. Numerical simulation results have indicated that the increase and decrease of the structural parameters of steering mechanism and tire parameters can restrain the selfexcited shimmy. With the change of some parameters, the vehicle speeds relating to the tire maximum angle amplitude of the selfexcited shimmy change correspondingly. The steering stiffness, tire cornering stiffness and pneumatic trail show greater impact on the amplitude of selfexcited shimmy.

Abstract:Aiming at solving the difficulty of effectively analyzing the fuel consumption characteristics of conventional vehicles, this paper statistically analyzed the engine operating time and the fuel consumption rate of several typical driving cycles, and used threedimensional distribution visual analysis to identify the detailed engine fuel consumption characteristics. A transit bus was simulated under several city cycles with the statistics of the engine speed, torque and time history of fuel rate. Results have shown that the vast majority of the engine operating points fall into the low speed and lowload zone, where the engine consumes a significant amount of fuel. Furthermore, the results have also indicated that the direction of engine energysaving, i.e. high efficiency region of the engine performance MAP should be shifted to the lowspeed and lowload zone where the vehicle operates most of the time. Also, the engine should be downsized with hybrid technology. This work has great practical value in guiding enterprises in product development and energysaving designs.

Abstract:The total Lagrangian formulation and implementation of radial point interpolation method (RPIM) was presented for the simulation of 2D bulk forming processes. In the present method, the displacement field function was approximated by using RPIM shape functions possessing Kronecker delta function property, which can facilitates the enforcement of essential boundary conditions. A simple contact searching algorithm was used to compute the contact force between the tools and the workpiece in the metal forming analysis and to solve the problems of the penalty method and Lagrangian multiplier method. In order to remedy the volumetric locking, the internal nodal forces of the workpiece were split into deviatoric part and volumetric part. The geometrical nonlinearities and material nonlinearities for the dynamic solution were treated by using the total Lagrangian description and an elasticplastic constitutive law. In order to remedy the volumetric locking, the workpiece was deformed into two parts, deviatoric part and volumetric part. The numerical examples show that RPIM is more efficient in dealing with large deformation problems such as bulk forming with severe distortion.

Abstract:To address the poor robust control and large scale parameter timevarying of inductionmotor variablefrequency speed regulation system in electric wheel dump truck, a kind of control scheme for inductionmotor variablefrequency speed regulation systems was proposed on the basis of the variable structure active disturbances rejection controller (ADRC), the change in rotor resistance was regarded as the inner disturbance of the flux subsystem , the effect of load change as exterior disturbances of the rotate speed subsystem respectively , and the extended state of an extended state observer (ESO) was used for estimation and compensation. The control scheme can solve such problems as the effect of timevarying parameter on the decoupling performance of a vector control system; and its dynamic control performance is superior to the traditional PI controller. Simulation result has verified the rationality and validity of the scheme.

Abstract:This paper presented a new detection method of voltage sag feature value, which was extracted from the module matrix of modified Stransform. In order to get the optimal performance, the parameter related to timefrequency resolution was determined on the basis of the flatness and minimal transition time. By means of the optimal timefrequency resolution, the amplitude of voltage sag duration less than 2 cycles could be detected accurately. The difference vector of base frequency was employed to detect sag duration so as to overcome the flaws of exiting Stransformbased methods, whose effects were unsatisfied when there were strong noise and no amplitude abrupt. A comparison between Stransformbased method and modifiedStransformbased method was made, and the results showed that the later was superior to the former in magnitude detection and duration localization.

Abstract:Microgas turbine distributed generation system model with dual PWM converter structure was studied. Permanent magnet synchronous machine side and grid side converters' control systems were designed on the basis of the droop characteristics. This control scheme could regulate permanent magnet synchronous machine speed and converter DC voltage. A dynamic model of microgas turbine distributed generation was built with Matlab, and simulations were completed under different load conditions. The result has shown that this model has good stability when the load suddenly changes. Rotor inertia response was introduced into this system, which improved the system′s dynamic quality,so the whole micro system can endure a big load mutation.

Abstract:A pore ordered and size controlled porous C/SiC composite was prepared with dipped and controlled pyrolysis of polycabosilan(PIP) bioporous carbon as the template derived from natural wood. The microstructure, antioxide property and mechanical properties of the composites obtained were characterized through XRD, SEM, BET, etc. The result showed that the phase of the SiC obtained was amporhous and combined well with the inner surface of BPC, which could raise the oxidation temperature of BPC by 150 ℃. With the increase of cycles times, the specific area of BPC/SiC decreased and the pores evaluated from rectangular to ellipse and finally to circle. The compressive strength of the composite first increased with the times of dippyrolysis cycle and then surrendered. A maximum axial compressive strength of 56.7 MPa occurred during 5 cycles, while 17.0 MPa of radical occurred during 6 cycles.

Abstract:Oxidation pitches were prepared from AR mesophase pitch preoxidized for different time at 300 ℃. Carbon foams were produced with AR mesophase pitch and the oxidation pitches. Element content and thermal decomposition processes of the pitches were analyzed with Nitrogen/oxygen and Carbon/sulfur analyzer and thermal analysis instrument. The microstructure of carbon foams was observed with SEM. The effects of preoxidization at 300℃ on composition and TG of AR mesophase pitch were investigated. After preoxidizing for 2 h, 4 h and 6 h at 300 ℃, the content of oxygen increased from 0.85% to 6.60%, 10.47% and 11.31%. Carbon foams had lesser aperture when the oxidation pitches were used as the precursor. The compressive strengths of carbonized and graphitized carbon foams were 12.07 MPa and 9.06 MPa when preoxidizing for 6 h at 300 ℃.

Abstract:Agrobacterium tumefaciensmediated transformation (ATMT)was applied in Penicillium simplicissimum H5 by Agrobacterium tumefaciens LBA4404. The results of hygromycinresistance selection, PCR and Southern blot analysis showed that TDNA was randomly inserted into the transformants with single copy and the transformants indicated genetic stability. The transformation efficiency was about 50 transformants per 105 spores by optimizing the coculture time, the concentration of Agrobacterium tumefacien and acetoyringone (AS).The application of ATMT technique in Penicillium simplicissimum H5 will provide a powerful tool for the genetic engineering of this fungus.

Abstract:PVP(polyvinyl pyrrolidone)/［Y(NO3)3+Al(NO3)3+Tb(NO3)3］ noncrystalline composite fibers were synthesized by electrospinning, and pure phase garnettyped Y3Al5O12∶Tb3+(denoted as YAG∶Tb3+ for short) luminescent nanofibers were fabricated by calcinating the obtained composite nanofibers at 900 ℃ for 10 h. The diameter of YAG∶Tb3+ nanofibers was ca. 70 nm, and the length was greater than 100 μm. The water, organic compounds and nitrate salts in the prepared composite nanofibers were decomposed and volatilized totally, and the mass of the sample kept constant when the sintering temperature was above 550 ℃, and the total weight loss percentage was 86.7%. YAG∶Tb3+ luminescent nanofibers emitted bright green light of 543 nm in a wavelength of Tb3+ ion characteristic emission under the excitation of 273 nm ultraviolet ray. The formation mechanism of YAG∶Tb3+ luminescent nanofibers was discussed. This method can be applied to prepare other rare earth garnettyped compound nanofibers.

Abstract:In order to investigate the effect of different disinfectants on the organic matter in drinking water, surface water from Huangpu River filtrated with MF membrane was studied. There was a significant difference among organic matter variations by chlorine, chloramine and UV. The oxidation of the organic matter in the water could be divided into highspeed and lowspeed stages with the variation of chlorine dosage from 1 mg/L to 4 mg/L. AOCNOX is the majority of the AOC composition in chloride water. AOC changes had a lesser extent and peak time lag than chlorine by chloramines disinfection. Irradiation by lowintensity UV (0.038 mW/cm2) had no effect on the AOC change. When AOC varied with the changes of UV dosage by highintensity（0.076 mW/cm2 and 0.153 mW/cm2), the changes of AOCP17 were consistent with AOC, and had no changes of AOCNOX.

Abstract:Government actions have direct and indirect effects on the information and communication technology (ICT) standards diffusion, and can significantly influenc the ICT standards for market potential. By optimizing the Bass model, importing the government nonconstant influence coefficient 'm' and changing the assumption that 'm' can not be changed, the ICT standards diffusion model under Government's participation was established, which was called GP model for short. South Korean CDMA technical standard diffusion, largely supported by the government, was analyzed on the basis of both the Bass model and the GP model. Through a comparison of the economic tests and statistical tests, the GP model turns out to be superior in analyzing the market potential of the technical standards under the government involvement. The conclusion was obtained through the empirical analysis that government actions can have a positive impact on the market potential for ICT technical standards and can promote its diffusion.