摘要：This paper studies the consistency of the extended Kalman filter(EKF) for a kind of nonlinear systems. Based on the EKF algorithm, the authors propose the quasi-consistent EKF(QCEKF)as well as the tuning law for its parameters. The quasi-consistency of the proposed algorithm is ***, the feasibility of the algorithm is illustrated by the numerical simulation on an orbit determination example.

摘要：A 32-bit pipeline accumulator with carry ripple topology is implemented for direct digital frequency *** increase the throughout while hold down the area and power consumption,a method to reduce the number of the pre-skewing registers is *** number is reduced to 29% of a conventional pipeline *** propagation delay versus bias current of the adder circuit with different size transistors is *** analyze the delay by employing the open circuit time constant *** to the simulation results,the maximum error is less than 8%.A method to optimum the design of the adder based on the propagation delay is *** clock traces for the 32-bit adder are heavily loaded,as there are 40 registers being connected to ***,the differential clock traces,which are much longer than the critical length,should be treated as transmission *** a clock distribution method and a termination scheme are proposed to get high quality and low skew clock signals.A multiple-type termination scheme is proposed to match the transmission line *** 32-bit accumulator was measured to work functionally at 5.3 GHz.

摘要：For different kinds of rocks,the collapse range of tunnel was studied in the previously published ***,some tunnels were buried in soils,and test data showed that the strength envelopes of the soils followed power-law failure *** this work,deep buried highway tunnel with large section was taken as objective,and the basic expressions of collapse shape and region were deduced for the highway tunnels in soils,based on kinematical approach and power-law failure *** order to see the effectiveness of the proposed expressions,the solutions presented in this work agree well with previous results if the nonlinear failure criterion is reduced to a linear Mohr-Coulomb failure *** present results are compared with practical projects and tunnel design *** numerical results show that the height and width of tunnel collapse are greatly affected by the nonlinear criterion for the tunnel in soil.

摘要：A harmonic vortex beam is a typical vector beam with a helical wavefront at harmonic frequencies(e.g.,second and third harmonics). It provides an additional degree of freedom beyond spin-and orbitalangular momentum, which may greatly increase the capacity for communicating and encoding information. However, conventional harmonic vortex beam generators suffer from complex designs and a low nonlinear conversion efficiency. Here, we propose and experimentally demonstrate the generation of a large second-harmonic(SH) vortex beam with quasi-nonlinear spin–orbit interaction(SOI). Highquality SH vortex beams with large topological charges up to 28 are realized experimentally. This indicated that the quasi-angular-momentum of a plasmonic spiral phase plate at the excitation wavelength(topological charge, q) could be imprinted on the harmonic signals from the attached WS2 monolayer. The generated harmonic vortex beam has a topological charge of l_(n)= 2 nq(n is the harmonic order). The results may open new avenues for generating harmonic optical vortices for optical communications and enables novel multi-functional hybrid metasurface devices to manipulate harmonic beams.

摘要：The electrical conductivity of NaF-AlF3-CaF2-Al2O3-ZrO2 system was studied by a tube-type cell with fixed cell constant. The results show that the electrical conductivity of NaF-AlF3-3%Al2O3-3%CaF2-ZrO2 molten salt system decreases with increase of ZrO2 content in an interval of 0-5%. The increase of 1%ZrO2 results in a corresponding electrical conductivity decrease of 0.02 S/cm, and the equivalent conductivity increases with the increase of molar ratio of NaF to AlF3. When the temperature increases by 1 °C, the electrical conductivity increases by 0.004 S/cm. At last, the regression equations of electrical conductivity relative to temperature and ZrO2 are obtained by quadratic regression analysis.

摘要：Stepped heating treatment has been applied to aluminum alloy thick plate to improve the mechanical performance and corrosion *** temperature control of the plate is the difficulty in engineering *** heating process,the calculation of surface heat transfer coefficient and the accurate temperature control method were studied based on measured heating temperature for the large-size thick *** results show that,the temperature difference between the surface and center of the thick plate is *** on the temperature uniformity,the surface heat transfer coefficient was calculated,and it is constant below300°C,but grows greatly over300°***,a lumped parameter method(LPM)was developed to predict the plate temperature.A stepped solution treatment was designed by using LPM,and verified by finite element method(FEM)and *** curves calculated by LPM and FEM agree well with the experimental data,and the LPM is more convenient in engineering application.

摘要：Particle image velocimetry technique was used to analyze the trailing vortices and elucidate their rela-tionship with turbulence properties in a stirred tank of 0.48 m diameter,agitated by four different disc turbines,in-cluding Rushton turbine,concaved blade disk turbine,half elliptical blade disk turbine,and parabolic blade disk ***-averaged and phase-resolved flow fields near the impeller blades were measured and the structure of trailing vortices was studied in *** location,size and strength of vortices were determined by the simplified λ2-criterion and the results showed that the blade shape had great effect on the trailing vortex *** larger curvature resulted in longer residence time of the vortex at the impeller tip,bigger distance between the upper and lower vortices and longer vortex life,also leads to smaller and stronger *** addition,the turbulent ki-netic energy and turbulent energy dissipation in the discharge flow were determined and *** turbulent kinetic energy and turbulent energy dissipation regions were located between the upper and lower vortices and moved along with *** restricted to single phase flow,the presented results are essential for reliable de-sign and scale-up of stirred tank with disc turbines.

摘要：In the present work,a principle of equipartition of entransy dissipation(EoED) for heat exchanger design is established,which says that for a heat exchanger design with given heat duty and heat transfer area,the total entransy dissipation rate reaches the minimum when the local entransy dissipation rate is uniformly distributed along the heat *** the heat transfer coefficient is unfixed,the total entransy dissipation obtained by the EoED principle is less than that obtained by the principle of equipartition of temperature difference(EoTD).Furthermore,the exchanger effectiveness obtained by the EoED principle is larger than that obtained by the EoTD *** the heat transfer coefficient is fixed,the EoED principle is equivalent to the EoTD *** show that the equipartition of entropy production(EoEP) and EoED principles give rise to difference in entropy generation and entransy dissipation for a heat exchanger optimization *** discrepancies are caused by distinct features of entropy production minimization and entransy dissipation minimization principles,the former is to optimize the design of heat exchanger by making the lost available work minimum,while the latter is not involved with heat-work *** is found that the entropy generation number is not suitable for evaluating heat exchanger performance,since it directly depends on the inlet and outlet temperatures of working *** the contrary,the entransy dissipation number is not directly related to the inlet and outlet temperatures of working ***,the entransy dissipation number is more suitable for serving as a criterion to evaluate heat exchanger performance.

摘要：The preferential oxidation of CO （CO‐PROX） is a hot topic because of its importance in pro‐ton‐exchange membrane fuel cells （PEMFCs）. Au catalysts are highly active in CO oxidation. Howev‐er, their activities still need to be improved at the PEMFC operating temperatures of 80–120 ＆#176;C. In the present study, Au nanoparticles of average size 2.6 nm supported on ceria‐modified Al2O3 were synthesized and characterized using powder X‐ray diffraction, nitrogen physisorption, transmission electron and scanning transmission electron microscopies, temperature‐programmed hydrogen reduction （H2‐TPR）, Raman spectroscopy, and in situ diffuse‐reflectance infrared Fourier‐transform spectroscopy. Highly dispersed Au nanoparticles and strong structures formed by Au–support in‐teractions were the main active species on the ceria surface. The Raman and H2‐TPR results show that the improved catalytic performance of the Au catalysts can be attributed to enhanced strong metal–support interactions and the reducibility caused by ceria doping. The formation of oxygen vacancies on the catalysts increased their activities in CO‐PROX. The synthesized Au catalysts gave excellent catalytic performances with high CO conversions （＆gt;97%） and CO2 selectivities （＆gt;50%） in the temperature range 80–150 ＆#176;C.

摘要：As a joint-optimization problem which simultaneously fulfills two different but correlated embedding tasks （i.e., entity embedding and relation embedding）, knowledge embedding problem is solved in a joint embedding scheme. In this embedding scheme, we design a joint compatibility scoring function to quantitatively evaluate the relational facts with respect to entities and relations, and further incorporate the scoring function into the maxmargin structure learning process that explicitly learns the embedding vectors of entities and relations using the context information of the knowledge base. By optimizing the joint problem, our design is capable of effectively capturing the intrinsic topological structures in the learned embedding spaces. Experimental results demonstrate the effectiveness of our embedding scheme in characterizing the semantic correlations among different relation units, and in relation prediction for knowledge inference.