摘要：Modem communications is an indispensable tool for modem social economy and modem social life. The payload of a communication satellite provides radio relay for links between earth stations. With most commercial communication satellites the payload consists of two distinct parts with well defined interfaces： the repeater and the antennas. The repeater designates the electronic equipment which performs a range of functions on the signals from the receiving antenna before delivering them to the transmitting antenna. The VX-SAT project is a system engineering exercise, realized in the China Academy of Space Technology （CAST） with the objective of training the persons in charge of designing futures communication satellites in the Bolivarian Agency of Space Activities （ABAE） in Venezuela. This paper includes an overview of the VX-SAT system, the preliminary design of the communications payload and finally the method used to design the redundancy ring of the transponder subsystem.

摘要：A Monte Carlo Analysis of nodes deployment for large-scale and non-homogeneous wireless sensor networks, has been done. Through simulations of random deployments of nodes over a square area using different densities, assuming that our network is composed by Anchor nodes （special sensors with known position） and simple Sensor nodes, the latter are supposed to estimate their own position after being placed within the coverage area with the minimum Anchor nodes needed to ＇feed＇ them with the necessary information. The goal is then to assist decision-makers in selecting among different alternatives to deploy the networks, according to resources features and availability, hence this method provides an estimate value of how many Anchor nodes should be deployed in a given area to trigger the location algorithm in the greatest possible number of Sensor nodes in the network.

摘要：Introduction Despite the numerous breakthroughs made in medical and biomedical technologies,biosensing underneath the skin without any associated pain still sounds like a dream yet to be *** invasive biosensors refer to functional or electronic sensors that can contact the interior environment of living organisms and their biological tissues,while the connected bulk devices remain on the surface of the biological objects[1].Minimally invasive biosensors are currently a key research area because they can not only meet the increasing technical demands to precisely detect biological activities inside biological objects,but also provide an ideal platform to externally incorporate complicated functionalities and electronic integration[2].The current development level of minimally invasive sensing still necessitates solving the constraints and bottlenecks in the three aspects of functionalities,sensitivity and biocompatibility[3].In this perspective,we select minimally invasive sensors as a representative research object with the aim to solve the limitations of current diabetes diagnosis and treatment approaches.

摘要：When using traditional game methods to study information security of the wireless sensor networks,players are mostly based on the assumption of completely *** on bounded rationality,the evolutionary game theory is used to establish the attack-defense model,analyze the strategy selection process of players,solve the evolutionarily stable strategy and design the optimal strategy selection ***,considering the strategy dependence,the incentive and punishment mechanism is introduced to improve the replicator dynamic *** simulation results show that the model is reasonable and the algorithm is effective,which provides new theoretical support for the security of wireless sensor networks.

摘要：Modern distance education essentially differs from traditional pattern of education in providing personalized education support service. This paper analyzes the status in which distance education provides personalized education support service nowadays. A distance education system is put forward based on Web usage mining techniques. Through analyzing the access behavior, the frequency, the browsing contents and the staying time of the students, get the general pattern of students access behaviors, and than provide personalized education support service comprehensively according to these analysis.

摘要：The quality of skeleton system for the cheetah robot goes hand in hand with its bionic result of its shape, structure and functions. In view of the skeleton system constitution and structural characteristic of the cheetah, the team applied structure design, stimulation analysis and parameter optimization to developing the cheetah robot. In addition, after the invention of cheetah robot＇s anterior lumbar vertebra based on its functional attribute and connectivity attribute, the Solidworks Simulation was utilized to analyze the design, according to which improvement on the lumbar vertebra was made. Plus, the advantages of the CAD and CAE made the high efficiency of design work and high quality of the cheetah robot possible.

摘要：The research on positioning system and spatial alignment is a big topic. In this paper, we proposed a design (that) studies two issues. One is the study of range positioning algorithm based on ZigBee communication system. The other one is spatial alignment platform which is controlled with two servos. Hardware and software control system was realized, which also consists of two parts, ZigBee network positioning system and automatic orientation platform.

摘要：The acidic tumor microenvironment is triggered by glycolysis in hypoxic condition, which can motivate the pHresponsive system to build certain triggers for efficiently tumor-targeted phototherapy. Additionally, the metalated porphyrin structures are widely studied in biomedical applications due to the favorable properties of high singlet oxygen quantum yield as well as strong fluorescence imaging ability. Herein, a pH-responsive zinc(II) metalated porphyrin(P-4) was designed and synthesized for amplifying cancer photodynamic/photothermal therapy with excellent fluorescence quantum yield(67.4%), superb singlet oxygen quantum yield(84.3%) and desired photothermal conversion efficiency(30.0%). In vitro, the self-assembled P-4 nanoparticles can specifically target to lysosome subcellular site and realize protonated process of dibutaneaminophenyl(DBAP) groups with high photo toxicity. Under single 660 nm laser illumination, the tumor can be ablated completely with no side effects in vivo. This work demonstrates that the p H-responsive P-4 nanoparticles provide a new avenue for highly efficient cancer combination therapy.

摘要：Mobile platform develops rapidly in recent years, with its performance and capacity increasing. A large number of virtual reality applications such as 3D simulation and visualization have appeared on mobile platform. However, due to restrictions, such as the lack of computing resources and the limited network bandwidth, the virtual reality systems on mobile platform could not have comparable performance as their peers on desktop platform. Taking resource restrictions into consideration, trade-offs have been made regarding the display of virtual reality systems. We propose a unified network scheduling strategy based on asynchronous multi-thread, database cache, prioritization and elimination of overdue requests. This strategy has been tested on the prototype system of virtual reality system on Android. The results demonstrate higher network resource utilization and better user experience.

摘要：Due to their unique surface chemistry,highly adjustable metal components,hydrophilicity,and high carrier concentrations,MXenes are applied in a variety of *** to other two-dimensional(2D)materials,building heterostructures with additional materials to form a 3D porous architecture for MXenes can significantly enhance their functionality and ***,the open structures and well-defined pathways of these 3D structured MXenes can improve ionic and electronic transport,thereby promoting their applications in electrochemical energy storage,sensing,catalysis,and *** this review,the recent efforts made on preparing 3D porous MXenes with heterostructures,focusing on MXenes/C,MXenes/inorganics,and MXenes/polymers were *** discussion covers aspects ranging from the design to synthesis of 3D porous MXenes,and their applications in photocatalysis,environmental monitoring and electrochemical energy *** review is concluded by presenting the prospects and insights on exploring the relationships between the porosity formation mechanisms,properties and applications of the 3D porous MXenes *** review can provide meaningful guidance for the design,fabrication and application of 3D porous MXenes in high-performance materials and devices.