摘要：This paper describes a commonly used pseudo-static method in seismic resistant design of the cross section of underground structures. Based on dynamic theory and the vibration characteristics of underground structures, the sources of errors when using this method are analyzed. The traditional seismic motion loading approach is replaced by a method in which a one-dimensional soil layer response stress is differentiated and then converted into seismic live loads. To validate the improved method, a comparison of analytical results is conducted for internal forces under earthquake shaking of a typical shallow embedded box-shaped subway station structure using four methods： the response displacement method, finite element response acceleration method, the finite element dynamic analysis method and the improved pseudo-static calculation method. It is shown that the improved finite element pseudo-static method proposed in this paper provides an effective tool for the seismic design of underground structures. The evaluation yields results close to those obtained by the finite element dynamic analysis method, and shows that the improved finite element pseudo-static method provides a higher degree of precision.

摘要：A cooperative region reconnaissance problem is considered in this paper where a group of agents are required to reconnoitre a region of interest. Amain challenge of this problem is the sensing region of each agent varies with its altitude within an altitude constraint. Meanwhile, the reconnaissance ability of an agent is determined by its altitude and radial distance. First, the region reconnaissance is formulated as an effective coverage problem, which means that each point in the given region should be surveyed until a preset level is achieved. Then, an effective coverage control law is proposed to minimize coverage performance index by adjusting the altitude of an agent. Finally, the effectiveness of the proposed control law is verified through numerical simulations.

摘要：Gd50Al3oCo20 wires show excellent magnetocaloric properties and high heat exchange rate due to the microsize. The Weibull and lognormal methods were used for systematically analyzing its mechanical properties for matching the design requirements in cooling system. The wire exhibits average fracture strength of-969.5 MPa and typical fracture behavior of amorphous character. Moreover, the distributions of stresses for tensile strains at 10 values are estimated by probability plot and Chi-square goodness-of-fit test. The random stresses were best fitted by lognormal probability distribution for most studied cases; however, fracture strength was best fitted by Weibull probability distribution. It is interesting to note that the mean and standard deviation of the stresses （to reach specific tensile strain） increase as the tensile strain grows, accompanied by the coefficients of variation of stresses which decrease smoothly. It is concluded that the inhomogeneity of material does cause the scatter of stresses growth, and the scatter could be considerably large.

摘要：The general computer-aided design （CAD） software cannot meet the mould design requirement of the autoclave process for composites, because many parameters such as temperature and pressure should be considered in the mould design process, in addition to the material and geometry of the part. A framed-mould computer-aided design system （FMCAD） used in the autoclave moulding process is proposed in this paper. A function model of the software is presented, in which influence factors such as part structure, mould structure, and process parameters are considered; a design model of the software is established using object oriented （O-O） technology to integrate the stiffness calculation, temperature field calculation, and deformation field calculation of mould in the design, and in the design model, a hybrid model of mould based on calculation feature and form feature is presented to support those calculations. A prototype system is developed, in which a mould design process wizard is built to integrate the input information, calculation, analysis, data storage, display, and design results of mould design. Finally, three design examples are used to verify the prototype.

摘要：In this paper, a composite control scheme for macro-micro dual-drive positioning stage with high accel- eration and high precision is proposed. The objective of control is to improve the precision by reducing the influence of system vibration and external noise. The positioning stage is composed of voice coil motor （VCM） as macro driver and piezoelectric actuator （PEA） as micro driver. The precision of the macro drive positioning stage is improved by the com- bined PID control with adaptive Kalman filter （AKF）. AKF is used to compensate VCM vibration （as the virtual noise） and the external noise. The control scheme of the micro drive positioning stage is presented as the integrated one with PID and intelligent adaptive inverse control approach to compensate the positioning error caused by macro drive positioning stage. A dynamic recurrent neural networks （DRNN） based inverse control approach is proposed to offset the hysteresis nonlinearity of PEA. Simulations show the positioning precision of macro-micro dual-drive stage is clearly improved via the proposed control scheme.

摘要：We have theoretically investigated two series of cyclometalated Pt（II） complexes, a series [Pt （C, N, N） Cl] and b series [Pt （C, N, Npyrazolyl） Cl]. The geometrical and electronic structures are calculated at the ECP60MWB//6-31G＊（H, C, Cl, N, S） basis set level using DFT method; one-photon absorption （OPA） properties are calculated by using both TDDFT and ZINDO methods and two-photon absorption （TPA） properties are obtained with the ZINDO/SOS method. The resonance integrals parameters （βsp and βd） for Pt are adjusted to -1 and -28.5 eV, respectively, to make max OPA wavelength calculated by ZINDO closest to the experimental data and TDDFT results. The calculated results indicate the molecule 2b （[Pt （Cnaphthyl, N, Npyrazolyl） Cl]） has the biggest potential as outstanding TPA materials because （i） the TPA properties of b series are more outstanding in IR wavelength range, the molecules in b series have good transparencies and possess 1-pyrazolyl-NH that is also available for another metal coordination （e.g., dimerization） and chemical interactions; （ii） when C is CnaphthyI in the C, N, N ligand of cyclometalated Pt（II） complexes, the molecules have the best conjugation effect and the best TPA properties.

摘要：The electrocatalytic N_(2)reduction reaction(NRR)is expected to supersede the traditional Haber-Bosch technology for NH3 production under ambient *** activity and selectivity of electrochemical NRR are restricted to a strong polarized electric field induced by the catalyst,correct electron transfer direction,and electron tunneling distance between bare electrode and active *** coupling the chemical vapor deposition method with the poly(methyl methacylate)-transfer method,an ultrathin sandwich catalyst,i.e.,Fe atoms(polarized electric field layer)sandwiched between ultrathin(within electron tunneling distance)BN(catalyst layer)and graphene film(conducting layer),is fabricated for electrocatalytic *** sandwich catalyst not only controls the transfer of electrons to the BN surface in the correct direction under applied voltage but also suppresses hydrogen evolution reaction by constructing a neutral polarization electric field without metal *** sandwich electrocatalyst NRR system achieve NH3 yield of 8.9μg h^(−1)cm^(−2)and Faradaic Efficiency of 21.7%.The N_(2)adsorption,activation,and polarization electric field changes of three sandwich catalysts(BN-Fe-G,BN-Fe-BN,and G-Fe-G)during the electrocatalytic NRR are investigated by experiments and density functional theory *** by applied voltage,the neutral polarized electric field induced by BN-Fe-G leads to the high activity of electrocatalytic NRR.

摘要：A type of high-order integral observers for matrix second-order linear systems is proposed on the basis of generalized eigenstructure assignment via unified parametric approaches. Through establishing two general parametric solutions to this type of generalized matrix second-order Sylvester matrix equations, two unified complete parametric methods for the proposed observer design problem are presented. Both methods give simple complete parametric expressions for the observer gain matrices. The first one mainly depends on a series of singular value decompositions, and is thus numerically simple and reliable; the second one utilizes the fight factorization of the system, and allows eigenvalues of the error system to be set undetermined and sought via certain optimization procedures. A spring-mass-dashpot system is utilized to illustrate the design procedure and show the effect of the proposed approach.

摘要：Hexagonal boron nitride(h-BN)ceramics have become exceptional materials for heat-resistant components in hypersonic vehicles,owing to their superior thermal stability and excellent dielectric ***,their densification during sintering still poses challenges for researchers,and their mechanical properties are rather *** this study,SrAl_(2)Si_(2)O_(8)(SAS),with low melting point and high strength,was introduced into the h-BN ceramics to facilitate the sintering and reinforce the strength and ***,BN-SAS ceramic composites were fabricated via hot press sintering using h-BN,SrCO_(3),Al_(2)O_(3),and SiO_(2) as raw materials,and effects of sintering pressure on their microstructure,mechanical property,and thermal property were *** thermal shock resistance of BN-SAS ceramic composites was *** show that phases of as-preparedBN-SAS ceramic composites are h-BN and h-SrAl_(2)Si_(2)O_(8).With the increase of sintering pressure,the composites’densities increase,and the mechanical properties shew a rising trend followed by a slight *** a sintering pressure of 20 MPa,their bending strength and fracture toughness are(138±4)MPa and(1.84±0.05)MPa·m^(1/2),*** sintered at 10 MPa exhibit a low coefficient of thermal expansion,with an average of 2.96×10^(-6) K^(-1) in the temperature range from 200 to 1200℃.The BN-SAS ceramic composites prepared at 20 MPa display higher thermal conductivity from 12.42 to 28.42 W·m^(-1)·K^(-1) within the temperature range from room temperature to 1000℃.Notably,BN-SAS composites exhibit remarkable thermal shock resistance,with residual bending strength peaking and subsequently declining sharply under a thermal shock temperature difference ranging from 600 to 1400℃.The maximum residual bending strength is recorded at a temperature difference of 800℃,with a residual strength retention rate of 101%.As the thermal shock temperature difference increase,the degree of oxida