摘要：Bridges crossing active faults are more likely to suffer serious damage or even collapse due to the wreck capabilities of near-fault pulses and surface ruptures under *** a high-speed railway simply-supported girder bridge with eight spans crossing an active strike-slip fault as the research object,a refined coupling dynamic model of the high-speed train-CRTS III slab ballastless track-bridge system was established based on *** rationality of the established model was thoroughly *** horizontal ground motions in a fault rupture zone were simulated and transient dynamic analyses of the high-speed train-track-bridge coupling system under 3-dimensional seismic excitations were subsequently *** safe running speed limits of a high-speed train under different earthquake levels(frequent occurrence,design and rare occurrence)were assessed based on wheel-rail dynamic(lateral wheel-rail force,derailment coefficient and wheel-load reduction rate)and rail deformation(rail dislocation,parallel turning angle and turning angle)*** optimization was then investigated in terms of the rail fastener stiffness and isolation layer friction *** of the wheel-rail dynamic indicators demonstrate the safe running speed limits for the high-speed train to be approximately 200 km/h and 80 km/h under frequent and design earthquakes,while the train is unable to run safely under rare *** addition,the rail deformations under frequent,design and rare earthquakes meet the safe running requirements of the high-speed train for the speeds of 250,100 and 50 km/h,*** speed limits determined for the wheel-rail dynamic indicators are lower due to the complex coupling effect of the train-track-bridge system under track *** running safety of the train was improved by increasing the fastener stiffness and isolation layer friction *** the rail fastener lateral stiffness of 60 kN/mm and isolat

摘要：Based on flexible pneumatic actuator(FPA),bending joint and side-sway joint,a new kind of pneumatic dexterous robot finger was *** finger is equipped with one five-component force sensor and four contactless magnetic rotary *** parts and FPAs are integrated,which reduces the overall size of the *** by FPA directly,the joint output torque is more accurate and the friction and vibration can be effectively *** improved adaptive genetic algorithm(IAGA) was adopted to solve the inverse kinematics problem of the redundant *** statics of the finger was analyzed and the relation between fingertip force and joint torque was ***,the finger force/position control principle was *** experiments of fingertip force/position were carried *** experimental results show that the fingertip position tracking error is within ±1 mm and the fingertip force tracking error is within ±0.4 *** is also concluded from the theoretical and experimental results that the finger can be controlled and it has a good application prospect.

摘要：The characteristics of oxy-coal combustion for a swirl burner with a specially designed preheating chamber are studied numerically. In order to increase the accuracy in the prediction of flame temperature and igni- tion position, eddy dissipation concept （EDC） model with a skeletal chemical reaction mechanism was adopted to describe the combustion of volatile matter. Simulation was conducted under six oxidant stream conditions with dif- ferent OjN2/CO2 molar ratios： 21/79/0, 30/70/0, 50/50/0, 21/0/79, 30/0/70 and 50/0/50. Results showed that 02 en- richment in the primary oxidant stream is in favor of combustion stabilization, acceleration of ignition and increase of maximum flame temperature, while the full substitution of N2 by CO2 in the oxidant stream delays ignition and decreases the maximum flame temperature. However, the overall flow field and flame shapes in these cases are very similar at the same flow rate of the primary oxidant stream. Combustion characteristics of the air-coal is similar to that of the oxy-coal with 30% 02 and 70% CO2 in the oxidant stream, indicating that the rear condition is suitable for retrofitting an air-coal fired boiler to an oxy-coal one. The swirl burner with a specially designed preheating chamber can increase flame temperature, accelerate ignition and enhance burning intensity of pulverized coal under oxy-coal combustion. Also, qualitative experimental validation indicated the burner can reduce the overall NOx emission under certain 02 enrichment and oxy-coal combustion conditions against the air-coal combustion.

摘要：This paper presents a novel field-programmable analog array （FPAA） architecture featuring a dual mode including discrete-time （DT） and continuous-time （CT） operation modes, along with a highly routable connection boxes （CBs） based interconnection lattice. The dual mode circuit for the FPAA is capable of achieving targeted op- timal performance in different applications. The architecture utilizes routing switches in a CB not only for the signal interconnection purpose but also for control of the electrical charge transfer required in switched-capacitor circuits. This way, the performance of the circuit in either mode shall not be hampered with adding of programmability. The proposed FPAA is designed and implemented in a 0.18 μm standard CMOS process with a 3.3 V supply voltage. The result from post-layout simulation shows that a maximum bandwidth of 265 MHz through the interconnection network is achieved. The measured results from demonstrated examples show that the maximum signal bandwidth of up to 2 MHz in CT mode is obtained with the spurious free dynamic range of 54 dB, while the signal processing precision in DT mode reaches 96.4%.

摘要：A dynamic measuring apparatus was developed to investigate the infiltration process of liquid metal into the fibrous preform. 10% （volume fraction） chopped carbon fiber preforms were infiltrated with magnesium alloy under different infiltration pressures. The threshold pressure and flow behavior of liquid metal infiltrating into the preforms were calculated and measured. The microstructure of obtained Ct4Mg composites was observed. The results indicate that the measured threshold pressure for infiltration was 0.048 MPa, which was larger than the calculated value. The infiltration rate increased with the increase of infiltration pressure, but the increase amplitude decreased gradually. The tiny pores in the composites could be eliminated by increasing the infiltration pressure. When the infiltration pressure rose to 0.6 MPa, high quality C1/Mg composite was obtained.

摘要：A rally integrated receiver RF front-end that meets WCDMA/GSM system requirements is *** supports SAW-less operation for *** improve the linearity in terms of both IP3 and IP2,the RF front-end is comprised of multiple-gated LNAs with capacitive desensitization,current-mode passive mixers with the proposed IP2 calibration circuit and reconfigurable Tow-Thomas-like biquad TIAs.A new power-saving multi-mode divider with low phase noise is proposed to provide the 4-phase 25%-duty-cycle *** addition,a constant-g_m biasing with an on-chip resistor is adopted to make the conversion gain invulnerable to the process and temperature variations of the *** RF front-end is integrated in a receiver with an on-chip frequency synthesizer in 0.13μm *** measurement results show that owing to this high-linearity RF front-end,the receiver achieves -6 dBm IIP3 and better than ＋60 dBm IIP2 for all modes and bands.

摘要：The compound diffractive telescope is a novel space optical system which combines the structure of compound eyes with diffractive optics and so it has a lighter weight, a wider field of view （FOV）, a lower cost as well as looser fabrication tolerance. In this paper, the design of a compound diffractive telescope composed of one primary lens and twenty-one eyepieces is introduced. Then the influence of diffraction orders on the performance of the system is analysed. A modified phase function model of diffractive optics is proposed to analyse the modulation transfer function （MTF） curves for 0° FOV, which provides a more accurate prediction of the performance of the system. In addition, an optimized mechanism is also proposed to suppress stray light. The star image and resolution tests show that the system can achieve diffraction limit imaging within ±2° of FOV and 4-4 mm of eccentricity. Finally, a series of pictures of an object are taken from different channels, and the splicing of pictures from adjacent FOVs is demonstrated. In summary, the designed system has been proved to have great potential applications.

摘要：To solve the problem of a low coal-loading rate being exhibited by the drum shearer on Chinese thin coal seams,systematic tests and research were performed to study the pivotal factors’influences on drum coal-loading rate using a model test *** effects of the drum hub diameter,cutting depth,vane helix angle,drum rotation speed and hauling speed on drum coal-loading rate were determined under circumstances of coal-loading with drum ejection and pushing modes,and reasons for these phenomena were *** results indicate that the influence of the drum cutting depth on the drum coal-loading rate is the most *** parameters of hub diameter,drum rotation speed and hauling speed can influence the drum coal-loading rate by cutting the coals’filling rate in the *** parameters of vane helix angle and drum rotation speed can influence drum coal-loading rates by influencing the ratio of cutting coals’tangential and axial speed in the *** coal-loading rate with drum ejection is clearly higher than that observed with drum *** in this study can provide support to design the drum structure and select drum operational parameters for a thin coal seam shearer.

摘要：Two essential blocks for the PLLs based on CP, a phase-frequency detector （PFD） and an improved current steering charge-pump （CP）, are developed. The mechanisms for widening the phase error detection range and eliminating the dead zone are analyzed and applied in our design to optimize the proposed PFD. To obtain excellent current matching and minimum current variation over a wide output voltage range, an improved structure for the proposed CP is developed by fully utilizing many additional sub-circuits. Implemented in a standard 90-nm CMOS process, the proposed PFD achieves a phase error detection range from -354° to 354° and the improved CP demonstrates a current mismatch of less than 1.1% and a pump-current variation of 4% across the output voltage, swinging from 0.2 to 1.1 V, and the power consumption is 1.3 mW under a 1.2-V supply.

摘要：A field experiment using a split-plot randomized complete block design with three replications was carried out to determine relationships between spectral indices and wheat grain yield （GY）, to compare the performance of four vegetation indices （VIs） for GY prediction, and to study the feasibility of VI to estimate grain protein content （GPC） in winter wheat. Two typical winter wheat （Triticum aestivum L.） cultivars ＇Xuzhou 26＇ （high protein content） and ＇Huaimai 18＇ （low protein content） were used as the main plot treatments and four N rates, i.e., 0, 120, 210, and 300 kg N ha^-1, as the sub-plot treatments. Increasing soil N supply significantly increased GY and GPC （P ≤ 0.05）. For the two cultivars combined, significant and positive correlations were found between four VIs and GY, with the strongest relationship observed when using the green ratio vegetation index （GRVI） at mid-filling. Cumulative VI estimates improved yield predictions substantially, with the best interval being heading to maturity stage. Similar results were found between VI and grain protein yield. However, when using cumulative VI, GPC showed no significant improvement. The strong relationship between leaf N status and GPC （R2 =0.9144 for ＇Xuzhou 26＇ and R2 = 0.8285 for ＇Huaimai 18＇） indicated that canopy spectra could be used to predict GPC. The strong fit between estimated and observed GPC （R2 = 0.7939） indicated that remote sensing techniques were potentially useful predictors of grain protein content and quality in wheat.