摘要：A nonlinear robust controller was presented to improve the tracking control performance of a flexible air-breathing hypersonic vehicle(AHV) which is subjected to system parametric uncertainties and unknown additive time-varying *** longitudinal dynamic model for the flexible AHV was used for the control ***-gain observers were designed to compensate for the system uncertainties and additive *** gain theorem and Lyapunov based stability analysis were utilized to prove the stability of the closed loop *** uniformly ultimately bounded tracking of the vehicle's velocity,altitude and attack angle were achieved under aeroelastic effects,system parametric uncertainties and unknown additive ***/Simulink simulation results were provided to validate the robustness of the proposed control *** simulation results demonstrate that the tracking errors stay in a small region around zero.

摘要：Wear particles of ultrahigh molecular weight polyethylene （UHMWPE） are the main cause of long-term failure of total joint replacements. Therefore, increasing its wear resistance or bioactivity will be very useful in order to obtain high quality artificial joints. In our study, UHMWPE composites filled with the bovine bone hydroxyapatite （BHA） were prepared by the method of compression moulding. A ball-on-disc wear test was carried out with a Universal Micro-Tribometer to investigate the friction and wear behavior of a Si3N4 ceramic ball, cross-sliding against the UHMWPE/BHA composites with human plasma lubrication. At the same time, the profiles of the worn grooves on the UHMWPE/BHA surface were scanned. The experimental results indicate that the addition of BHA to UHMWPE had a significant effect on the biotribological behavior of UHMWPE cross-sliding against the Si3N4 ceramic ball. The addition of BHA powder enhanced the hardness and modulus of elasticity of these composites and decreased the friction coefficients and wear rates under conditions of human plasma lubrication. When the added amount of BHA powders was up to 20%-30%, UHMWPE/BHA composites demonstrated the designed performance of the mechanical properties and biotribological behavior.

摘要：Considering a one-supplier and two-retailer supply chain setting in which the supplier makes contacts with retailers in sequence based on FCFS(first–come–first-service) principle, the authors investigate the marginal effect of extra-gain guilty fairness concerns of supply chain members on the contract design, supply chain's profit and profit distribution. When the supplier considers distributional fairness of loss aversion and extra-gain guilty, extra-gain guilty concern reduces the optimal wholesale and retail price, and improves supply chain performance. When the first or the second retailer considers distributional fairness and peer-induced fairness, extra-gain guilty concerns decrease the optimal wholesale and retail price but increase the profit of all supply chain members only when the level of loss aversion is large enough and the level of extra-gain guilty is less than 1/2. However, when the level of loss aversion is small and the level of extra-gain guilty is less than 1/2, extra-gain guilty has no influence on supply chain performance. The analysis reveals that the supply chain performance can be further improved by considering fairness of extra-gain guilty.

摘要：The nominal Ti44Al6Nb1.0Cr2.0V alloy was newly designed and prepared by vacuum consumable melting technique with the ingot sizes of d225 mm×320 mm. The results show that the average lamella colony size is 780-1830 μm. This as-cast alloy has a modified near lamellar(M-NL) structure that is composed of mainly larger(α2+γ) lamella colonies and smaller(B2+equiaxed γ) blocky morphology. It exhibits the moderate tensile properties at room temperature, in which the Region(5) yields the ultimate tensile strength(UTS) about 499 MPa and the elongation about 0.53%. The obvious brittle fracture characteristics and trans-granular interlamellar fracture are the predominant modes. After room temperature tensile testing, there are some <101] and a few 1/2<112] superdislocations in the γ phase. The as-cast microcrack is the main factor to deteriorate the tensile property, which results in the premature fracture, poor ductility and few dislocations. The addition of Nb, Cr and V can decrease stacking fault energy(SFE) obviously, which is helpful to enhancing the ductility of the alloy.

摘要：The 2D data processing adopted by the high-density resistivity method regards the geological structures as two degrees, which makes the results of the 2D data inversion only an approximate interpretation;the accuracy and effect can not meet the precise requirement of the inversion. Two typical models of the geological bodies were designed, and forward calculation was carried out using finite element method. The forward-modeled profiles were obtained. 1% Gaussian random error was added in the forward models and then 2D and 3D inversions using a high-density resistivity method were undertaken to realistically simulate field data and analyze the sensitivity of the 2D and 3D inversion algorithms to noise. Contrast between the 2D and 3D inversion results of least squares inversion shows that two inversion results of high-density resistivity method all can basically reflect the spatial position of an anomalous body. However, the 3D inversion can more effectively eliminate the influence of interference from Gaussian random error and better reflect the distribution of resistivity in the anomalous bodies. Overall, the 3D inversion was better than 2D inversion in terms of embodying anomalous body positions, morphology and resistivity properties.

摘要：This study gives an analytical solution for wave interaction with a partially reflecting vertical wall protected by a submerged porous bar based on linear potential theory. The whole study domain is divided into multiple sub-regions in relation to the structures. The velocity potential in each sub-region is written as a series solution by the separation of variables. A partially reflecting boundary condition is used to describe the partial reflection of a vertical wall. Unknown expansion coefficients in the series solutions are determined by matching velocity potentials among different sub-regions. The analytical solution is verified by an independently developed multi-domain boundary element method(BEM) solution and experimental data. The wave run-up and wave force on the partially reflecting vertical wall are estimated and examined, which can be effectively reduced by the submerged porous bar. The horizontal space between the vertical wall and the submerged porous bar is a key factor, which affects the sheltering function of the porous bar. The wave resonance between the porous bar and the vertical wall may disappear when the vertical wall has a low reflection coefficient. The present analytical solution may be used to determine the optimum parameters of structures at a preliminary engineering design stage.

摘要：这份报纸与不可分的输入为非线性的系统经由产量反馈考虑分散的适应规定 -- 状态马厩(iISS ) 逆动力学，非线性的无常，和未知控制方向。在获得的靠近环的系统的所有信号被围住，这被显示出，并且 asymptotic 规定被完成。一个数字例子显示出设计的有效性。

摘要：A design of polarization-maintaining retro-reflectors （PMRRs） for folded-path applications is proposed and analyzed. The prism-based scheme enables the output light, which is parallel to the input, to have an identical state of polarization. The principle of the design is theoretically verified, and the related error is analyzed due to possible manufacturing imperfection. The maximum spatial angle error is ±2.75°. The effect on the extinction ratio and insertion loss is also discussed, which further proves the design＇s feasibility in practical applications.

摘要：In order to study the differences in vertical component between onshore and offshore motions,the vertical-to-horizontal peak ground acceleration ratio(V/H PGA ratio) and vertical-to-horizontal response spectral ratio(V/H) were investigated using the ground motion recordings from the K-NET network and the seafloor earthquake measuring system(SEMS).The results indicate that the vertical component of offshore motions is lower than that of onshore *** V/H PGA ratio of acceleration time histories at offshore stations is about 50%of the ratio at onshore *** V/H for offshore ground motions is lower than that for onshore motions,especially for periods less than 0.8 ***,based on the results in statistical analysis for offshore recordings in the K-NET,the simplified V/H design equations for offshore motions in minor and moderate earthquakes are proposed for seismic analysis of offshore structures.

摘要：Fingerprint has been widely used in a variety of biometric identification systems in the past several years due to its uniqueness and immutability. With the rapid development of fingerprint identification techniques, many fingerprint identification systems are in urgent need to deal with large-scale fingerprint storage and high concurrent recognition queries, which bring huge challenges to the system. In this circumstance, we design and implement a distributed and load-balancing fingerprint identification system named Pegasus, which includes a distributed feature extraction subsystem and a distributed feature storage subsystem. The feature extraction procedure combines the Hadoop Image Processing Interface（HIPI） library to enhance its overall processing speed; the feature storage subsystem optimizes MongoD B＇s default load balance strategy to improve the efficiency and robustness of *** and simulations are carried out, and results show that Pegasus can reduce the time cost by 70% during the feature extraction procedure. Pegasus also balances the difference of access load among front-end mongos nodes to less than 5%. Additionally, Pegasus reduces over 40% of data migration among back-end data shards to obtain a more reasonable data distribution based on the operation load（insertion, deletion, update, and query） of each shard.