摘要：The inverse design of electron lens is realized by two different methods in this paper. One is damped least square method and the other is the artificial neural network method. Their merits and defects are discussed according to our calculation results in the paper. In the condition of selecting the learning samples properly, the artificial neural network has obvious advantages in the inverse design of electron lens. It is an effective method to solve the inverse design problem in the electron optic system.

摘要：A design method of the apodizing functions for guided-wave four-port electrooptic tunable filter (EOTF) is proposed. As an example, the specific form of Gaussian apodizing function is designed by analyzing the crosstalk performance of EOTF. Crosstalk is calculated based on the transient response of the filter to an input optical pulse. It is concluded that crosstalk level below -30 dB for 20-Gb/s data rates and 100-GHz channel spacing is achievable with presently available substrate dimensions.

摘要：The H∞ output feedback control problem for uncertain discrete-time switched systems is reasearclled. A new characterization of stability and H∞ performance for the switched system under arbitrary switching is obtained by using switched Lyapunov function. Then, based on the characterization, a linear matrix inequality （LMI） approach is developed to design a switched output feedback controller which guarantees the stability and H∞ performance of the closed-loop system. A numerical example is presented to demonstrate the application of the proposed method.

摘要：The design approach of H∞ autopilot for autonomous underwater vehicles (AUVs) is proposed. Comprised by the three sub-controllers,i.e. speed,heading and depth controllers,the designed autopilot has advantage over existing H∞ control of AUVs. The overshoot in speed,heading and depth control systems under step commands is restricted by refining the weighting function for robust stability. The dynamic performance of heading and depth control systems is improved by feeding back yaw rate and pitch angle,respectively. To evaluate the design approach,it is then utilized to synthesize the autopilot for flight control of Subzero Ⅲ,a low cost test-bed for AUV control techniques. Both simulations and water trails verify the effectiveness of the design approach.

摘要：The effects of water/binder ratio （w/b） on the toughness behavior, compressive strength and flexural strength of engineered cementitious composites （ECC） were investigated. The w/b ratios of 0.25, 0.31, 0.33 and 0.37 were selected and the specimens were tested at the ages of 7 d and 28 d. The experimental results showed that there was a corresponding increase in first cracking strength, modulus of rupture, compressive strength and flexural strength with the decrease of w/b. Within the w/b range of 0.25-0.37, higher w/b was found to have improved effects on deflection, strain hardening index and toughness index of ECC. In the permission of meeting the requirement of compressive strength grade, selecting higher w/b in mix design will help to obtain robust ECC.

摘要：In this paper, we present a modified projection method for the linear feasibility problems （LFP）. Compared with the existing methods, the new method adopts a surrogate technique to obtain new iteration instead of the line search procedure with fixed stepsize. For the new method, we first show its global convergence under the condition that the solution set is nonempty, and then establish its linear convergence rate. Preliminary numerical experiments show that this method has good performance.

摘要：A novel degradable pH-sensitive hydrogel with pendent carboxyl groups was designed and synthesized from ethylenediaminetetraacetic dianhydride （EDTAh） and butanediamine （BDA） with dicyclohexylcarbodiimide （DCC） as a condensating agent and BDA as a crosslinking agent. The obtained polymers were characterized by ^13C NMR, ^1H NMR and FTIR. The swelling experiments of the hydrogel in pH 3, 7, and 12 media indicated much higher swelling ratio in pH 12 media than in pH 3 and pH 7 media, exhibiting sound pH sensitivity. The pH sensitivity of this type of hydrogel may be regulated through controlling the type and the dose of the crosslinking agent.

摘要：Aiming at exploring the excellent structural performance of the vein-stiffening membrane structure of dragonfly hind wings,we analyzed two planar computational models and three 3D computational models with cambered corrugation based on the finite element *** is shown that the vein size in different zones is proportional to the magnitude of the vein internal force when the wing structure is subjected to uniform out-of-plane transverse *** membrane contributes little to the flexural stiffness of the planar wing models,while exerting an immense impact upon the stiffness of the 3D wing models with cambered *** a lumped mass of 10% of the wing is fixed on the leading edge close to the wing tip,the wing fundamental fre-quency decreases by 10.7%～13.2%;if a lumped mass is connected to the wing via multiple springs,the wing fundamental fre-quency decreases by 16.0%～18.0%.Such decrease in fundamental frequency explains the special function of the wing pterostigma in alleviating the wing quivering *** particular features of dragonfly wings can be mimicked in the design of new-style reticulately stiffening thin-walled roof systems and flapping wings in novel intelligent aerial vehicles.

摘要：Zero correlation window （ZCW） or zero correlation zone （ZCZ） sequence can be used in quasi-synchronous code division multiple access （QS-CDMA） system to eliminate multiple access and multipath interferences. However, as the length of ZCW or ZCZ increases, fewer sequences are available. Recently, a new concept, sequence set with group-wise zero correlation window is introduced, which can increase the number of available sequences for a QS-CDMA system. In this article, a new method for generating sequence set with group-wise zero correlation window is presented. This method is based on a Hadamard matrix of size N×N and a pair of Hadamard matrices of size M×M. Compared with previous methods, the proposed sequence set has a group-wise zero correlation window for both periodic and aperiodic cross-correlation functions.

摘要：Bacteria with helical flagella show an ideal mechanism to swim at low Reynolds number. For application of artificial mi- croswimmers, it is desirable to identify effects of structural and geometrical parameters on the swimming performance. In this study, a double-end helical swimmer is proposed based on the usual single-end helical one to improve the forward-backward motion symmetry, The propulsion model of the artificial helical microswimmer is described. Influences of each helix parameter on the swimming velocity and propulsion efficiency are further analyzed. The optimal design for achieving a maximum propulsion velocity of submillimeter scale swimmers is performed based on some constraints. An experimental setup consisting of three-pair of Helmholtz coils is built for the helical microswimmers. Experiments of microswimmers with several groups of parameters were performed, and the results show the validity of the analysis and design.