摘要：Aqueous zinc-ion batteries(AZIBs)show great potential for applications in grid-scale energy storage,given their intrinsic safety,cost effectiveness,environmental friendliness,and impressive electrochemical ***,strong electrostatic interactions exist between zinc ions and host materials,and they hinder the development of advanced cathode materials for efficient,rapid,and stable Zn-ion *** and their derivatives possess a large interlayer spacing,excellent hydrophilicity,outstanding electronic conductivity,and high redox *** materials are considered“rising star”cathode candidates for *** comprehensive review discusses recent advances in MXenes as AZIB cathodes from the perspectives of crystal structure,Zn-storage mechanism,surface modification,interlayer engineering,and conductive network design to elucidate the correlations among their composition,structure,and electrochemical *** work also outlines the remaining challenges faced by MXenes for aqueous Zn-ion storage,such as the urgent need for improved toxic preparation methods,exploration of potential novel MXene cathodes,and suppression of layered MXene restacking upon cycling,and introduces the prospects of MXene-based cathode materials for high-performance AZIBs.

摘要：The Weihe River Basin has a significant number of tributaries and a delicate ecological *** the spatial and temporal evolution and determinants of landscape ecological risk in the Weihe River Basin(WRB)can improve the scientific protection and development of its watershed *** study is based on land use statistics from the WRB for a 30-year period represented by 1990,2000,2010,and *** initial model for the assessment of landscaping ecological hazards was created using the software that was also used to generate the landscape ecological risk index,such as ArcGIS 10.4 and Fragstats ***,the spatial and temporal evolution of landscape ecological risk in the vicinity of the study area was characterized by the trajectory of the center of gravity migration and the spatial autocorrelation of ***,Geodetector was used to analyze ecological risk drivers in the *** to the findings,the high-risk and relatively high-risk regions are steadily expanding,while the low-risk and relatively low-risk areas dominate the ecological risk landscape in the *** the Weihe River Basin,Xianyang and Xi'an are the areas to which the high-risk centers of gravity are *** spatial correlations were found between the landscape ecological hazards in the study area,most prominently in the form of high-high and low-low *** primary drivers are the interplay between the GDP component,temperature,and elevation as a single factor.

摘要：机机翼前缘结冰会改变机翼的气动轮廓并影响整体的空气动力学性能.研究简化角冰冰形对翼型绕流流场结构的影响可以为飞机防冰设计提供有价值的参考.采用粒子图像测速技术,在低速直流风洞中对覆盖不同角冰冰形的翼型在不同攻角时的流场结构进行了详细的实验测量.实验对象包括三种简化的冰形和原始冰形.结果表明,在本研究范围内,覆盖简化冰形的翼型和覆盖原始冰形的翼型在流场参数上的最大差异为35.11%.与原始冰形相比,覆盖简化的角冰冰形的翼型流场中的分离泡距离翼型前缘和后缘更远.在三种冰形简化方法中,将冰角简化成矩形并在冰角之间添加抛物线的连接方式具有比较好的简化效果.在选定的两个区域中,这种简化冰形和原始冰形在翼型绕流流场的参数平均值的差异在14.88%之内.

摘要：The recent decade has witnessed an upsurge in the demands of intelligent and simplified Internet of Things(IoT)networks that provide ultra-low-power communication for numerous miniaturized *** the research community has paid great attention to wireless protocol designs for these networks,researchers are handicapped by the lack of an energy-efficient software-defined radio(SDR)platform for fast implementation and experimental *** SDRs perform well in battery-equipped systems,but fail to support miniaturized IoT devices with stringent hardware and power *** paper takes the first step toward designing an ultra-low-power SDR that satisfies the ultra-low-power or even battery-free requirements of intelligent and simplified IoT *** achieve this goal,the core technique is the effective integration ofµW-level backscatter in our SDR to sidestep power-hungry active radio frequency *** carefully develop a novel circuit design for efficient energy harvesting and power control,and devise a competent solution for eliminating the harmonic and mirror frequencies caused by backscatter *** evaluate the proposed SDR using different modulation schemes,and it achieves a high data rate of 100 kb/s with power consumption less than 200µW in the active mode and as low as 10µW in the sleep *** also conduct a case study of railway inspection using our platform,achieving 1 kb/s battery-free data delivery to the monitoring unmanned aerial vehicle at a distance of 50 m in a real-world environment,and provide two case studies on smart factories and logistic distribution to explore the application of our platform.

摘要：The linguistic dynamic systems (LDSs) based on type-1 fuzzy sets can provide a powerful tool for modeling,analysis,evaluation and control of complex ***,as pointed out in earlier studies,it is much more reasonable to take type-2 fuzzy sets to model the existing uncertainties of linguistic *** this paper,the LDS based on type-2 fuzzy sets is studied,and its reasoning process is realized through the perceptual reasoning *** properties of the perceptual reasoning method based LDS (PR-LDS) are *** properties demonstrated that the output of PR-LDS is intuitive and the computation complexity can be reduced when the consequent type-2 fuzzy numbers in the rule base satisfy some ***,a data driven method for the design of the PR-LDS is *** last,the effectiveness and rationality of the proposed data-driven method are verified by an example.

摘要：The central composite design in the modeling and optimization of catalytic dehydration of ethanol to ethylene was performed to improve the ethylene yield.A total of 20 experiments at random were conducted to investigate the effect of reaction temperature,Si/Al ratios of H-ZSM-5 catalyst and liquid hourly space velocity(LHSV) on the ethylene *** results show that the relationship between ethylene yield and the three significant independent variables can be approximated by a nonlinear polynomial model,with R-squared of 99.9%and adjusted R-squared of 99.8%.The maximal response for ethylene yield is 93.4%under the optimal condition of 328 ℃,Si/Al ratio 85,and LHSV 3.8 h-1.

摘要：受最新材料科学、计算机技术、人工智能和自动控制技术的启发,新一代交通基础设施正在走向数字化和智能化。世界上许多主要发达国家都在因地制宜,积极推动智能创新技术在交通基础设施中的应用。本文首先简要介绍了交通基础设施智能化的基本概念、科学依据和发展历程。然后,按照设计、施工、运维、淘汰的全生命周期链条,系统分析了智能化技术的研究现状和面临的主要挑战。随后,以世界上第一条基于智能建设理念建设的铁路——北京-张家口高铁为例,全面介绍了智能技术的最新成就。最后,从标准体系、理论方法和人才培养三个维度对交通基础设施智能化的未来发展进行了探讨。

摘要：The kinematic accuracy of space manipulator determines whether the spacecraft performs normally or not. Problems pertaining to structural deformation have received increased attention in recent times. In the space manipulator systems, flexible arms and joints can induce drastic dynamic instabilities. In applications such as the space station, kinematic error due to structural deformation can jointly affect the performance characteristics. And it is crucial for accuracy control of space manipulator to establish a precision index. Here we analyze the dynamics characteristic of flexible space manipulator considering the hysteresis of harmonic reducer based on method of nonconstraint boundary modal. For the sake of describing the output accuracy, we integrate the method of analytic hierarchy process(AHP) to establish a comprehensive evaluation index. A numerical simulation is performed to analyze the nonlinear dynamic characteristics of space manipulator with harmonic reducer. With the analysis of accuracy assessment, the relation among the hysteresis angle, rigidity and output accuracy is revealed. Considering the elastic modulus of flexible space manipulator and the hysteresis angle of harmonic reducer, we conduct an evaluation of output characteristics of flexible space manipulator with the proposed comprehensive evaluation index. The accuracy evaluation of output characteristics based on the proposed comprehensive evaluation index is implemented in the initial stage of space manipulator's design, which can not only solve the problems existing in the design but also save cost savings for ground tests. The results can be used in designing and optimizing future space manipulators, which may provide valuable references for design and thermal control of the space manipulator.

摘要：engineering designs for mountainous highways emphasize compliance checking to ensure safety. However, relying solely on compliance checking may lead designers to minimize costs at the expense of high risk indicators, since the overall risk level of the highway design is unknown to the designers. This paper describes a method for the simultaneous consideration of traffic safety risks and the associated cost burden related to the appropriate planning and design of a mountainous highway. The method can be carried out in four steps: First, the highway design is represented by a new parametric framework to extract the key design variables that affect not only the life-cycle cost but also the operational safety. Second, the relationship between the life-cycle cost and the operational safety risk factors is established in the cost-estimation functions. Third, a fault tree analysis (FTA) is introduced to identify the traffic risk factors from the design variables. The safety performance of the design solutions is also assessed by the generalized linear-regression model. Fourth, a theory of acceptable risk analysis is introduced to the traffic safety assessment, and a computing algorithm is proposed to solve for a cost-efficient optimal solution within the range of acceptable risk, in order to help decision-makers. This approach was applied and examined in the Sichuan–Tibet Highway engineering project, which is located in a complex area with a large elevation gradient and a wide range of mountains. The experimental results show that the proposed approach significantly improved both the safety and cost performance of the project in the study area.

摘要：This paper describes a bi-level programming model that seeks to simultaneously optimize location and design decisions of facilities in a distribution system in order to realize company's maximal total profit subject to the constraints on the facility capacity and the investment *** the upper-level problem,twoechelon integrated competitive/uncompetitive capacitated facility location model,which involves facility location and design,is *** the lower-level problem,customer is assumed to patronize store based on facility utility which is expressed by service time cost in the store and its travel cost to ***'s facility choice behavior is presented by a stochastic user equilibrium assignment model with elastic *** such a distribution system design problem belongs to a class of NP-hard problem,a genetic algorithm(GA)-based heuristic procedure is ***,a numerical example is used to illustrate the application of the proposed model and some parameter sensitivity analyses are presented.