摘要：High-speed trains have very complex running environments,which contain single-train running in open air,two-trains passing by in open air,single-train running in tunnel and two-trains passing by in *** the environment wind appears,crosswind effects must be *** design of high-speed trains mainly aims at the drag,lift,moment,impulse pressure waves,aerodynamic noise,*** typical running *** the paper,the aerodynamic design processes of CRH380A and 380B are introduced and the aerodynamic performances of different designs are analyzed and *** tunnel experiments and running tests indicate that the new generation of high-speed trains have excellent aerodynamic performances.

摘要：This paper proposes a compact polarization microstrip antenna based on double-layer structure. The band- width of the whole antenna is widened by expanding the top and bottom layers respectively. After the design of antenna structure and adjustment of size, the proposed antenna can achieve both the left- and right-hand circular polariza- tions in 2.33 GHz--2.97 GHz. Measurement results indicate that the effective bandwidth is 640 MHz in S-band and the relative bandwidth can achieve 24% with S, less than- 15 dB.

摘要：For most legged robots the drive-motors are mounted on the joints of legs, which increase leg＇s mass and rotary inertia. When mounted on legs, the drive-motor has to rotate clockwise and anticlockwise periodically to swing a leg back and forth. Larger inertia of the leg, as well as the ever-changing status of frequent acceleration and deceleration of the motors, limits the moving speed of the legged robots. This article proposes an improved mechanical design to overcome such problems. All the drive-motors are installed on the robot body to reduce the rotary inertia of the legs. Then a crank-rocker mechanism is used to transform continuous rotation of motors to back and forth motion of the leg. With this scheme, the motor may reach higher rotation speed since it drives a lighter leg with no change of the rotation direction. In addition, an elastic tendon is attached to the ankle to reduce the pulse stress on the leg. Kinematics and dynamics analysis demonstrates that the new design enlarges end-workspace, reduces driving torque and increases ground reaction force, which means the new robot has lager stride and higher swing frequency of leg to achieve faster moving.

摘要：Based on the principle of turned mass damper(TMD) systems,the conceptual design of semi-submersible platform with a moveable heave-plate(MHS) has been put *** heave motion response amplitude operator(RAO) and viscous damping of the MHS platform are calculated by iteration,and the coupling stiffness between the MHS hull and the heave-plate is optimized to decrease the maximum heave motion response of the MHS hull under 10-year survival conditions in the South china *** nu-merical results indicate that the heave motion RAO of the MHS hull can be decreased in the range of predominant wave frequencies,which may provide some reference to the heave motion control of offshore platforms.

摘要：In recent years,conjugated polymers have attracted great attention in the application as photovoltaic donor materials in polymer solar cells(PSCs).Broad absorption,lower-energy bandgap,higher hole mobility,relatively lower HOMO energy levels,and higher solubility are important for the conjugated polymer donor materials to achieve high photovoltaic ***-chain engineering plays a very important role in optimizing the physicochemical properties of the conjugated *** this article,we review recent progress on the side-chain engineering of conjugated polymer donor materials,including the optimization of flexible side-chains for balancing solubility and intermolecular packing(aggregation),electron-withdrawing substituents for lowering HOMO energy levels,and two-dimension(2D)-conjugated polymers with conjugated side-chains for broadening absorption and enhancing hole *** the molecular structural optimization by side-chain engineering,the2D-conjugated polymers based on benzodithiophene units demonstrated the best photovoltaic performance,with powerconversion efficiency higher than 9%.

摘要：Fullerene derivatives as a kind of star carbon materials have received intense investigation because of their three-dimensional shape,anisotropic electron mobility,and high electron ***,the cutting-edge developments of fullerene nanomaterials have had a tremendous impact on a wide range of applications,such as organic solar cells,field effect transistors,and *** explore their full potential applications,research into fullerene-based multilevel nanostructures relying on hierarchical interactions from bottom to top is rapidly *** is of great theoretical and practical significance to prepare multilevel fullerene nanostructures with structural and properties controlled by optimizing the influencing *** review would offer several aspects including the chemical structures of organic molecules and the nanostructures of the organic molecules and fullerene-organic *** monolayers or multilayers,fullerene molecules tend to fall into a space of suitable size,in which the located positions are affected by the intermolecular *** the covered surfaces,fullerenes are more likely to approach the electron-withdrawing units through the donor-acceptor and charge transfer *** the implementation of this review,an exhaustive analysis on the chemical modification,including the molecular backbone and substituents,preformed network synergies,and adsorption sites is *** addition,the relationship between the molecules and structures that illustrates the importance of the molecular design for the controlled fullerenes hybrid nanostructures can be further understood based on the results of the joined experimental and computational investigations.

摘要：With the development of superlubricity, the requirement for the accuracy of measuring super low friction force becomes more and more high. In this study, a novel micro-tribometer has been designed. The resolution and accuracy of friction force are 0.01 m N by using the dual frequency laser interferometer. Experiments were performed to investigate the ability of measuring friction force from different aspects. The interference signal mixed in the measured friction force curve was analyzed and can be removed by a designed filter. The results of experiment show that the tribometer is capable of measuring a super low friction force in the order of magnitude of 0.01 m N with an applied load up to 1 N.

摘要：Anisotropic polyaniline （PAni） plates decorated with self-aligned nanofiber arrays were synthesized under the hydrothermaI conditions. The formation mechanism of the self-assembled structures was investigated by studying the effect on PAni micro-structure with additive electrolyte in reaction system, and numerical simulation for dependence of systematic electrostatic energy on cross angles of self-assembled nanofiber arrays in grid textured PAni plates. It is proposed that the electrostatic interaction based on ionic doping charges plays an important role in the formation of the self-assembled PAni structures.

摘要：Cascading stages of high-gain harmonic generation(HGHG) free electron laser(FEL) is a promising way to produce fully coherent X-ray *** a test facility for modern FEL R&D,the Shanghai deep ultraviolet FEL(SDUV-FEL) is now under upgrading for the cascading two stages of HGHG *** the energy of the electron beam is as low as about 185 MeV after upgrade,the total harmonic number of this two stages HGHG is only 2×2,and the wavelength of the final radiation is 196.5 nm which is the 4th harmonic of the 786 nm seed *** help of three-dimensional simulation codes,design studies on the FEL physics for the cascaded HGHG experiment are present based on the parameters of the upgraded SDUV-FEL *** is found from the simulation results that the part of the electron beam which has been used in the first stage can still generate powerful radiation in the radiator of the second stage,and this radiation will be difficult to be separated from the radiation generated by the fresh part of the electron *** overcome this problem,a novel method based on the energy spectrum of the electron beam is proposed in this paper to demonstrate the "fresh bunch" technique.

摘要：A low power VCO with a wide tuning range and low phase noise has been designed and realized in a standard 90 nm CMOS technology. A newly proposed current-reuse cross-connected pair is utilized as a negative conductance generator to compensate the energy loss of the resonator. The supply current is reduced by half compared to that of the conventional LC-VCO. An improved inversion-mode MOSFET（IMOS） varactor is introduced to extend the capacitance tuning range from 32.8% to 66%. A detailed analysis of the proposed varactor is provided. The VCO achieves a tuning range of 27–32.5 GHz, exhibiting a frequency tuning range（FTR） of 18.4%and a phase noise of –101.38 dBc/Hz at 1 MHz offset from a 30 GHz carrier, and shows an excellent FOM of –185dBc/Hz. With the voltage supply of 1.5 V, the core circuit of VCO draws only 2.1 m A DC current.