Abstract:The energy regenerative characteristic of vehicle electromagnetic suspension is analyzed based on the power flow. In order to solve the key problem of energy quantification of electromagnetic suspension,a calculation and analysis method of energy conversion efficiency is proposed. A comparative work between the active system,passive system and the maximal output power system is made through computer simulation. It is demonstrated that in the aspect of vehicle dynamics,the active system is superior to the passive system. In the aspect of energy regenerative ability,the passive system is superior to the active system. And the energy regenerated by the active system is more than the consumed energy. So the active system has the ability of powering itself.

Abstract:Based on the fact that friction coefficient changes with the friction surface temperature,the influence of friction coefficient on automatic mechanical transmission (AMT) is studied during repeated starting process. A model is established for the transmitted torque of clutch and the temperature rise on clutch plate surface during AMT starting. Based on the launching control rule of “fast-slow-fast”,the repeated starting for AMT and the friction work of the friction pair are simulated. The simulation results show that friction coefficient changes with the change of the friction work. After several starting,friction coefficient and the transmitted torque of clutch diminish a lot,and the slipping between drive plate and clutch plate always exist, therefore,the vehicle can’t start.

Abstract:Car interior noise induced by windshield wiper system is tested for four different types of cars under high and low wiping speeds,and sound samples for subjective annoyance study are prepared. Grouped pair-wise comparison is adopted for the subjective evaluation test. The characteristic of subjective values and relation of four psychoacoustic parameters to the subjective annoyance are analyzed in two wiping speeds and various wiping patterns. The results indicate that the annoyance caused by wiper noise at high speed is higher than that at low speed,and downwards wiping noise is more annoying than upwards wiping noise. The work concluded that the subjective annoyance of noise from wiper system could be described by binaural loudness and fluctuation.

Abstract:A torque characteristics mathematics-mechanical model of dual mass flywheel is established. The torque characteristics curve which is consistent with the test results is obtained by dynamics simulation analysis of the dual mass flywheel by using ADAMS. It is concluded that the work process of the dual mass flywheel can be more authentic and the torque can be increased greatly by taking the friction characteristics into account in the simulation model. Moreover,by the wedging friction of the spring seats’ heads, the torque non-linearly increases on the condition of large torsion angle. Thus the requirements that low torque and small torsion angle should be flexible,high torque and large torsion angle should be of high counter torque are satisfied. Then the design goal that the driven system’s first-order and second-order resonant speeds are beyond the normal speed of the engine can be achieved.

Abstract:Ultrasonic vibration honing is an effective method for precision machining of cylinder liner,while the flutter caused by inner factors of the system would seriously affect the surface quality of combustion engine. Ultrasonic honing mechanism and dynamic honing deep are considered to establish a dynamic model of ultrasonic honing flutter system and the relationship between the limit honing width and honing speed is deduced based on the theory of regenerative flutter. Simulation is carried out to obtain the effect of different parameters including stiffness coefficient,damping ratio,spindle speed and reciprocation motion speed on the stability limit curve of the flutter system. It can be concluded that the ultrasonic honing system is prone to emerge flutter with less than 400 r/min of spindle speed and the limit honing width of flutter happening is 27 μm. Higher stiffness and damping ratio can make system stabler.

Abstract:To develop Mg-Gd-Y based high-strength alloys and widen the application of magnesium alloys, the effects of Y addition on the microstructure and mechanical properties of Mg-12Gd-1Zn-0.6Zr alloy are investigated by using both optical and electron microscopy,X-ray diffraction (XRD),differential scanning calorimetric (DSC) analysis,and tensile test．The results indicate that adding 2%Y to the Mg-12Gd-1Zn-0.6Zr alloy does not cause an obvious change in the as-cast microstructure of the alloy. However,after adding 3%and 4%Y,the as-cast microstructure of the alloy is coarsened,and simultaneously the morphology of the secondary phases in the alloy is changed from the initial discontinuous fine network to thick skeleton-like frame. Furthermore,adding 2%-4%Y to the Mg-12Gd-1Zn-0.6Zr alloy can also refine the grains of the as-extruded alloy,and adding 2%and 3%Y can obtain higher refining efficiency than adding 4%Y. In addition,adding 2%-4%Y to the Mg-12Gd-1Zn-0.6Zr alloy can also effectively improve the ultimate tensile strength and yield strength of the as-extruded alloy,and the ultimate tensile strength,yield strength and elongation of the as-extruded alloy with the addition of 2%Y can reach 348.8 MPa,256.8 MPa and 14.7%,respectively.

Abstract:In order to optimize the quenching parameters of ultra high strength steel 22MnB5,orthogonal experimental design method is applied to design the experiments and response surface methodology (RSM) is used to analyze the experimental results. Austenitizing temperature and soaking time are taken as the optimization factors. The effect of these factors on quenching hardness and elongation are investigated. The optimization results of each single objective are firstly obtained. Then,ideal point method is used to find the solution to the multi-objective programming,and global optimums are gained. Finally,the optimal results are discussed from the microstructure angle and the reliability of the prediction models is demonstrated.

Abstract:The high temperature mechanical properties of SUP9,50CrVA,60Si2Mn,which are typical spring steels,are investigated with the Gleeble-1500 thermal analogue machine. Hot ductility and strength curves of these steels are measured in the temperature range of 600 ℃ to 1 350 ℃. Fracture mechanisms of the steels are analyzed based on the observation of the fracture surface with the help of scanning electron microscope (SEM). The effects of the inclusions and composition on high temperature mechanical property are discussed. The results show that there are two low ductility zones,brittle zone Ⅰ(Tm-1 315 ℃,Tm-1 281 ℃,Tm-1 316 ℃) and brittle zone Ⅲ(600-930 ℃,650-956 ℃,600-980 ℃). Origin of the former is that liquid membrane formed in interdendritic regions caused by concentration of S,P and O elements. Origin of the latter is that the appearance of ferrite thin film between austenitic grain boundaries and the precipitation of AlN.

Abstract:In order to promote the resource recycling of titanium contained in waste slag,the melting properties of CaO-Al2O3-SiO2-TiO2slag are studied through melting experiment and theoretical calculation by using thermodynamic software Factsage. The experimental index is the melting temperature of the slag,and the effect factors are binary basicity,the mass percent of Al2O3 and TiO2. The three factors’ change range are as follows,binary basicity 4~7.9,Al2O3 30%~45% and TiO2 1%~7%. The research results are as follows. The effect of binary basicity is significant,but other factors’ effects are not. Under the experimental conditions,the optimal combination of the lowest melting temperature for the slag are binary basicity 6.6,Al2O3 35%and TiO25%,and the corresponding melting temperature is 1 354 ℃. While the content of TiO2 is lower than 3%,the liquid region area has little change and can be ignored. While the content of TiO2 is under the range of 3%~10%,the liquid region is larger when the content of TiO2 is higher. Under the experimental study conditions,the melting properties of this slag system can meet the requirements of refining slag in steelmaking.

Abstract:A new feature extraction method is proposed to recognize different types of partial discharge (PD) signals. Firstly,four typical categories of PD artificial defect models are made and S transform (ST) is employed to obtain a time-frequency representation of the recorded UHF signals. Then,two-directional two-dimensional principal component analysis ((2D) 2PCA) is applied to compress the ST amplitude (STA) matrix to extract features. Finally,support vector machine (SVM) combined with particle swarm optimization (PSO) algorithm is introduced to accomplish the recognition of experimental samples. Classification results demonstrate that the average recognition rate of (10,5) combination is the highest while the one of (5,5) combination is the lowest among four kinds of feature dimension combinations. Moreover,PSO can obviously improve the classification performance of SVM. Specifically,all the average recognition rates of PSO-SVM are higher than 94.43%and the maximum value comes to 97.67%. Therefore,the feature sets extracted by ST and (2D) 2PCA can not only achieve dramatic dimension reduction,but also retain the major information of original data. It is proved that the proposed algorithm can obtain ideal results in PD pattern recognition.

Abstract:The range of magnetostrictive displacement sensors (MDS) is directly determined by the electromagnetic properties of the magnetostrictive line (ML). The small measuring range of domestic MDS is caused by the ML of Fe-Ni. In accordance with the problem,applying the ML of Fe83Ga17to MDS is proposed and the possibility is demonstrated from the point of electromagnetic properties. A magnetic field model based on the fourier analysis and electromagnetic theory is firstly built,which lays a foundation for the research on electromagnetic properties. And then,the distribution of the magnetic field simulated by MATLAB helpful for wiedemann effect is obtained. The feasibility of our scheme is demonstrated by the good effect of echo signal finally.

Abstract:An algorithm is proposed for dual-transistors forward converter (DTFC) by using the principle of charge balance control during a transient process to improve their dynamic performance. Combined with response curve,the theoretical analysis and some key equations are presented to improve the dynamic performance of the DTFC by minimizing the over/under shoot and the recovery time. In order to avoid the magnetic saturation of the transformer,an approximate method is introduced in the calculation of the optimal switching time,which can also be applied to other isolated converters when the maximum duty cycle is limited. Finally,the simulation results and the experimental results of the prototype show that,compared with the traditional voltage mode control,the proposed algorithm can significantly improve the dynamic performance of DTFCs.

Abstract:According to the resolution and investigation depth deficiency of traditional dynamic receiving focusing (DRF) beamforming in ultrasound imaging,a dual focusing beamforming method based on virtual element is proposed. Firstly,single fixed focus point is used in the first focusing; and then the delay parameters used in the second focusing are calculated with the concept of virtual element; in the end the second focusing is carried out by delay-and-sum dynamic focus technique to obtain the imaging data. The experiments based on point pattern are used to verify the proposed method. The experimental results indicate that dual focusing beamforming applied to ultrasound imaging can resolve the contradiction between resolution and investigation depth in some extent and the method of dual focusing beamforming can effectively improve the imaging quality.

Abstract:The analysis of PAHs in sediments of 12 sampling sites from Chongqing section of the Yangtze River shows that total PAHs concentration ranges from 0.64~3.98 μg/g in dry season and 0.85~4.63 μg/g in wet season,with the maximum content of phenanthrene accounting for 11%~27% of total PAHs. The 3~5 rings PAHs are dominant in sediment samples,while the content of PAHs with 2 and 6 benzene rings is small. Moreover,the compositions of PAHs are significantly different as they are taken from different sampling periods,releasing more 6-ring PAHs in rainy season. The combustion of fossil fuels and oil spillages of ships may be dominant sources in the study area and the degree of sediment contamination by PAHs is moderate in comparison with other internal and external sediments. However,fluorene and phenanthrene exceed the probable effect level (PEL),which might certain potential damage to the ecosystem in the studied area.

Abstract:Surface water samples are collected throughout the upstream Liangtan River in December, 2010. The concentrations of Cu, Zn, Ni, Pb, Cr and Fe, Mn, Mg are determined using atomic absorption spectrometry (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) respectively for the contamination characteristics analysis and preliminary risk assessment. The results demonstrate that concentrations of 8 heavy metals show significant differences in different sampling sections of the river. The average concentration of Ni, Pb, Fe and Mn are much higher than the limits value of GB 3838-2002 Ⅲ functional area and their section of over standard are 100%, 87.5%, 50% and 43.75%, respectively. Spatial distribution and correlation analysis reveal that Fe and Mn in river may have the same pollution sources. Preliminary health risk assessment results indicate that Pb is the most important pollutant leading to non-carcinogenic concerns in particular for children, and the next is Cr. Mn, Ni, Cu, Fe and Zn in sequence.

Abstract:A strain Z-2 is originally obtained from sodium desulfurization wastewater and underwent domestication step by step to adapt to high salt content solution. Z-2 is capable of bio-oxidating inorganic sulphuric compound. When NaCl concentrations are 10~20 g/L and 30 g/L, the biological oxidation rate of Z-2 are 90% and 70% respectively. The bioactivity and ability for oxidating sulphuric is completely inhibited when salt content reaches 40 g/L. The optimum cultivation condition of Z-2 are initial pH value of 7.5, temperature of 35 ℃ and ammonium sulfate concentration of 2 g/L. Under this condition, the oxidation rate for the actual wastewater equivalent inorganic sulphuric compound (Na2SO3 70 g/L, Na2S2O3 10 g/L and NaCl 20 g/L) is higher than 95%.

Abstract:As the present result of gas extraction by conventional methods in soft low permeability of high-gas mine is not satisfying, deep hole presplitting controlling blasting technology is adopted in Changwu Tingnan coal mine, Shaanxi province. The amount of a single drilling gas extraction increases by 1.36 times, face gas extraction rate edges up to 50% and seam permeability coefficient increases by 9 times. By taking some comprehensive measures, such as enhancing ventilation, drainage, extraction of hydrogen sulfide and lime slurry injection in the blast holes, the hydrogen sulphide is controlled in advanced and the concentration is controlled blow 2×10 -6~4×10 -6, thus the working environment is effectively improved and the safety in production is ensured.

Abstract:It’s proved for the first time that external solution can promote gas desorption by using independently designed gas desorption measuring device. Two reasons of competed adsorption location between liquid and gas and capillary static driver are analyzed. The result shows that the gas desorption efficiency increases as the concentration of penetrant solution increases and the promotion effect of penetrant solution only occurs in a period of time. Then specific measurements of improving gas desorption efficiency on coal face are proposed. The study can provide reference for solving the time constraint between gas extraction and mining on coal face.

Abstract:In the paper, the influence of stain and heat effect caused by the variation of stresses in the temperature governing equation, and the influence of temperature variation in the constitutive equations and the non-Fourier effect of heat conduction are all considered, and the thermo-mechanical equation of isotropy and linear thermo-elastic material including the temperature gradient is deduced. The influence of relax time on the space-time distributions of temperature increment and stresses are discussed in the ceramic membranes with finite thickness for 1-D transient question which subjects to single pulse heat deposition. The result shows that, for the ceramic, the difference of speed between heat wave and expand wave reaches the order of magnitude, and the couple effect of thermo-mechanics has little influence on the speed of propagation. Since the single pulse heat deposition belongs to the thermal physical quantities, the heat wave is the domain speed of propagation, and the mechanical quantities belong to the high-order small quantities.

Abstract:The sequence of global earthquake magnitude of 7.0 and more than 7.0 is analyzed by the methods of Hurst exponent, fractal dimension D, correlation coefficient C and V-statistics and the scatter diagram and fitting trend line. The results show that this sequence is a fractional Brownian motion, mean reversion process (pink noise, anti-persistence and persistence against the state), and with a frequent reversal mutation or volatility. In the long case, the magnitude shows a very slight downward trend. Conclusion of the study can provide reference for seismic studies and safety studies.

Abstract:A new type of adsorbent, collagen fiber immobilized metal-ions(MICF) is prepared on the base of some metal-oxide salts and collagen fiber, and its adsorption behavior for removing fluoride in solution is investigated. It is suggested that ZrCF has good adsorption property for fluoride and in the pH range of 4.0-9.0, ion intensity has little effect on adsorption. In addition, the coexisting anions such as Cl -,NO -3 and SO 2-4 has no interference for adsorption. The ZrCF is described by means of SEM, surface charge and FTIR. It is obviously that Zr(Ⅳ) is uniformly impregnated on collagen fiber by means of SEM. The pHpzc increases up to 9.0 determined by the solid addition method. It is shown that the major adsorption mechanism is coordination exchange using the changes in pH value of solution and FTIR. In the adsorption procedure, the coordination complexation between Zr(Ⅳ)metal hydroxyl groups at the surface of ZrCF and fluoride occurs, and H + is discharged.

Abstract:As for the livestock-poultry’s environmental system’s typical feature, a systematic warning approach for the livestock-poultry’s environmental system is proposed on the basis of cusp catastrophe theory. Livestock-poultry’s environmental system’s potential function is taken as state function, potential function’s equation is established and a cusp catastrophe warning model is constructed in order to ensure the discriminate of cusp catastrophe. The carrying capacity of livestock-poultry’s environmental system is taken as warning instance indexes and pollution emission relative intensity and the number of poultry feeding are taken as alarm aura, then V-level warning for livestock-poultry’s environmental system is carried out. Combined with example analysis, the result shows that based on the cusp catastrophe, the warning method of livestock-poultry’s environmental system’s precaution is available.

Abstract:To realize automatic control, it is important to study the response of reactor to electric field. A three-dimensional biofilm eletrode reactor is developed and steadily operated to remove nitrogen. In the reactor, oxygen is produced on the anode and hydrogen is produced on the cathode of the three-dimensional electrode by electrolysis water. Microorganism in the reactor utilize oxygen and hydrogen adequately to remove nitrogen by nitrification-denitrification. To evaluate the correlation of electric field with the reactor, DO, pH and nitrogen removal efficiency are studied. Results show that when a electric field of 0.013 4 mA/cm 2 is applied to the system, the removal rate of NH +4-N, NO -3-N and TN is 90%, 70% and 70%, respectively. To assure the reactor run efficiently, the maximum of the intensity of electric field applied to the reactor is 0.0201 mA/cm 2. Within 0.0201 mA/cm 2, the system is in stable running status, while DO and pH is altered resulting from the intensity of electric field. With enhancing the intensity of electric field, the removal rate of NO -3 -N can be improved, although, the removal rate of NH +4-N is not elevated markedly. There is no accumulation of NO -2 -N within 0.0201 mA/cm 2.

Abstract:When gob-side roadways in inclined coal seam are retained by strike long wall mining method, the conveyor roadway are retained under ascending mining and the ventilation roadway is retained under underhand mining. In order to research the differences of roof activity in the two conditions, stack continuous layer boards model and load strips segmentation method are used and the influence of the coal seam dip angle is considered. Then the solving formulas of roadside support resistance under such conditions are obtained. Through comparison and analysis, it shows that roadside support resistance of conveyor roadway gob-side entry retaining is much greater than ventilation roadway gob-side entry retaining. When ventilation roadway gob-side entry retaining is used, roadside support resistance reduces with the coal seam dip angle increases. While conveyor roadway gob-side entry retaining is adoptel, roadside support resistance increases with the coal seam dip angle increases. But when the coal seam dip angle is larger than the natural repose angle of goaf caving gangue, the resistance can be reduced by considering the effect of goaf gangue accumulation. The conclusion provides reference for choosing mining sections order of gob-side entry retaining in inclined coal seam.