摘要：Crickets, similar to some other insects, have highly sensitive filiform hairs on their cerci that can detect miniscule changes in airflow. This study imitates the perception mechanism of these filiform sensory hairs of crickets by designing and fabricating a Multi-electrode Metal Core Piezoelectric Fiber （MMPF）-based airflow sensor. Four longitudinal conductive sheets were coated symmetrically on their surfaces with Metal-core Piezoceramic Fibers （MPF）. The four fan-shaped piezoelectric ceramics with surface electrode covers were polarized. After successful polarization, the cantilevered MMPF could be used as an airflow sensor. The four electrodes on the surface were symmetrically divided into two groups. Therefore, two signals can be produced by a single fiber sensor. The theoretical model of an MMPF airflow sensor has been established. The model indicates that the ratio of the two signals is equivalent to the tangent of the airflow angle. Furthermore, the sum of the squares of the two signals is not dependent on the angle, but reflects the velocity of the airflow. Therefore, a single MMPF can be used to measure both the direction and amplitude for a given airflow. The theoretical model has been confirmed via experimental measurements.

摘要：Ultra-high strength alloys with good ductility are ideal materials for lightweight structural application in various industries. However, improving the strength of alloys frequently results in a reduction in ductility, which is known as the strength-ductility trade-off in metallic materials. Current alloy design strategies for improving the ductility of ultra-high strength alloys mainly focus on the selection of alloy composition （atomic length scale） or manipulating ultra-fine and nano-grained microstructure （grain length scale）. The intermediate length scale between atomic and grain scales is the dislocation length scale. A new alloy design concept based on such dislocation length scale, namely dislocation engineering, is illustrated in the present work. This dislocation engineering concept has been successfully substantiated by the design and fabrication of a deformed and partitioned （D＆P） steel with a yield strength of 2,2 GPa and an uniform elongation of 16%. In this D＆P steel, high dislocation density can not only increase strength but also improve ductility. High dislocation density is mainly responsible for the improved yield strength through dislocation forest hardening, whilst the improved ductility is achieved by the glide of intensive mobile dislocations and well-controlled transformation-induced plasticity （TRIP） effect, both of which are governed by the high dislocation density resulting from warm rolling and martensitic transformation during cold rolling. In addition, the present work proposes for the first time to apply such dislocation engineering concept to the quenching and partitioning （Q＆P） steel by incorporating a warm rolling process prior to the quenching step, with an aim to improve simultaneously the strength and ductility of the Q＆P steel. It is believed that dislocation engineering provides a new promising alloy design strategy for producing novel strong and ductile alloys.

摘要：Due to the deformation ability even under small loads, hydrogels have been widely used as a type of soft materials in various applications such as actuating and sensing, and have attracted many researchers to study their behaviors. In this paper, the behavior of hydrogel micro-valves with reverse sensitivity to the p H inside a T-junction flow sorter is investigated. With the fluid-structure interaction(FSI) approach, the effects of various parameters such as the inlet pressure and the p H value on the stress and deformation of the micro-valves are examined, and the results with and without FSI,including the flow rate and the closure p H, are compared. In order to reduce the response time of hydrogels, the effects of three different patterns on the performance of the microvalves are explored. Eventually, it is concluded that FSI is a key influential factor in designing and analyzing the behaviors of hydrogels.

摘要：A new procedure for a design of multi-range controllers for use with highly nonlinear systems is *** procedure involves obtaining the describing function models of the nonlinear plant by software followed by designing a controller at nominal ***,the controller parameters are optimized to yield a satisfactory closed-loop response at all operating ***,the performance and stability of the closed-loop system comprised of the designed controller and the nonlinear plant are *** procedure and the associated software are applied to a nonlinear control problem of the sort encountered in aerospace,and the results are compared with two other approaches.

摘要：One of the core semiconductor devices is the electrostatic chuck. It has been widely used in plasma- based and vacuum-based semiconductor processing. The electrostatic chuck plays an important role in adsorbing and cooling/heating wafers, and has technical advantages on non-edge exclusion, high reliability, wafer planarity, particles reduction and so on. This article extracts key design elements from the existing knowledge and techniques of electrostatic chuck by the method proposed by Paul and Beitz, and establishes a design space systematically. The design space is composed of working objects, working principles and working structures. The working objects in- volve electrostatic chuck components and materials, classifications, and relevant properties; the working principles involve clamping force, residual force, and temperature control; the working structures describe how to compose an electrostatic chuck and to fulfill the overall functions. The systematic design space exhibits the main issues during electrostatic chuck design. The design space will facilitate and inspire designers to improve the design quality and shorten the design time in the conceptual design.

摘要：Electrochemical machining (ECM) is an effective and economical manufacturing method for machining hard-to-cut metal materials that are often used in the aerospace field. Cathode design is very complicated in ECM and is a core problem influencing machining accuracy, especially for complex profiles such as compressor blades in aero engines. A new cathode design method based on iterative correction of predicted profile errors in blade ECM is proposed in this paper. A mathematical model is first built according to the ECM shaping law, and a simulation is then carried out using ANSYS software. A dynamic forming process is obtained and machining gap distributions at different stages are analyzed. Additionally, the simulation deviation between the prediction profile and model is improved by the new method through correcting the initial cathode profile. Furthermore, validation experiments are conducted using cathodes designed before and after the simulation correction. Machining accuracy for the optimal cathode is improved markedly compared with that for the initial cathode. The experimental results illustrate the suitability of the new method and that it can also be applied to other complex engine components such as diffusers. (C) 2016 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.

摘要：Most commercial and industrial facilities require very low temperatures for refrigeration and high temperatures for space heating and hot water purposes. Single stage heat pumps have not been able to meet these temperature demands and have been characterized by low capacities and coefficient of performance(COP). Cascade heat pump has been developed to overcome the weaknesses of single stage heat pumps. This study reviews recent works done by researchers on cascade heat pumps for refrigeration, heating and hot water generation. Selection of suitable refrigerants to meet the pressure and temperature demands of each stage of the cascade heat pump has been discussed. Optimization of design parameters such as intermediate temperature(low stage condensing and high stage evaporating temperatures), and temperature difference in the cascade heat exchanger for optimum performance of the cascade heat pump has been reviewed. It was found that optimising each design parameter of the cascade heat pump is necessary for maximum system performance and this may improve the exergetic efficiency, especially of cascade refrigeration systems, by about 30.88%. Cascade heat pumps have wider range of application especially for artificial snow production, in the supermarkets,for natural gas liquefaction, in drying clothes and food and as heat recovery system. The performance of cascade heat pumps can be improved by 19% when coupled with other renewable energy sources for various real time applications. Also, there is the need for much research on refrigerant charge amount of cascade heat pumps, refrigerant-refrigerant heat exchangers to be used as cascade heat exchanger, cascade heat pumps for simultaneous cooling, heating and hot water generation and on the use of variable speed compressors and their control strategies in matching system capacity especially at part load conditions.

摘要：2k factorial design is employed to find the mathematical relation between the carbon content and intercritical annealing temperature （IAT） in order to predict the responses namely martensite volume fraction （MVF）, microhardness （H）, yield strength （YS）, ultimate tensile strength （UTS）, total elongation （TEL）, yield ratio （YR） and Charpy impact energy （CIE） in dual phase （DP） steels. Steels containing different carbon contents （0.085% C and 0.380% C） had been chosen for this purpose. The main advantages of factorial design are its easy implementation and the effective computation compared with the other optimization techniques, which were employed for predicting mentioned responses in the literature. To verify the proposed approach based on factorial design, experiments for verification were performed. The results of the verification experiments and the mathematical models are in accordance with each other and the literature.

摘要：This work is concerned with the problem of L2 gain disturbance attenuation for nonlinear systems and nonlinear robust control for power systems. In terms of the recurrence design approach proposed, the nonnegative solution of dissipative inequality and the storage function of nonlinear H∞ control for a generator excitation system are acquired. From this storage function, the excitation controller is constructed. Moreover, simulation results manifest the effectiveness of this design method.

摘要：High-speed machine tool working table restrains the machining accuracy and machining efficiency,so lightweight design of the table is an important *** nature,leaf has developed a plate structure that maximizes the surface-to-volume *** can be seen as a plate structure stiffened by *** with a high-speed machine tool working table,leaf veins play a role of supporting part which is similar to that of stiffening ribs,and they can provide some new design ideas for lightweight design of the *** this paper,distribution rules of leaf veins were investigated,and a structural bionic design for the table was achieved based on regulation of leaf ***,statistical analysis on geometric structure of leaf veins was carried out,and four distribution rules were ***,relevant mechanical models were developed and analyzed in finite element *** on the results from mechanical analysis on those relevant models,the four distribution rules were translated into the design rules and a structural bionic design for the working table was *** simulation and experimental verifications were carried out,and results showed that the average displacement of the working table was reduced by about 33.9%.