Spatial shape reconstruction using orthogonal fiber Bragg grating sensor array

With distributed orthogonal fiber Bragg grating (FBG) sensor arrays used as modular detection units, an implementation method for deformation detection and spatial shape reconstruction of a frame model structure was proposed in this paper. After brief introduction of curvature detection principle of FBG sensor, the design, fabrication and encapsulation of the FBG modular detection unit were illustrated detailedly. Every unit was composed of four optical fibers, each containing an array of FBG strain sensors. In addition, the method and procedure of the reconstruction algorithm of three dimensional spatial curve based on orthogonal curvature were also described in detail, as well as discrete curvature continuity method. The constructed algorithm was applied to reconstruction the vibration deformation of the experimental frame model, in which four FBG modular detection units were embedded. Afterward, experimental test and verification were performed for static bending and dynamic excitation of the frame model structure, using the developed experiment system. And experimental results verified the feasibility and effectiveness of deformation detection and spatial shape reconstruction based on orthogonal FBG sensor array. Moreover, the results indicated that the proposed method can provide useful research thinking for the further study of active monitoring of flexible space structures.     

基于状态空间连续逼近的云计算虚拟资源优化配置研究

针对云计算中虚拟资源的优化配置问题,提出了一种基于状态空间连续逼近的云计算虚拟资源的优化配置方法.首先利用一个带时间扩展的标记转移系统,对虚拟资源在申请和调用过程中各对象的动作行为以及状态转移关系进行描述;然后根据对象之间的并发关系,推导出一组能够描述系统中每种对象各状态数量随时间变化的微分方程组;最后通过求解方程组,分析在供需平衡状态下各虚拟资源的实际需求,动态地配置各虚拟资源的数量,实现虚拟资源动态优化配置的目的.     

Synthesis and Characterization of Planar Five‐Ring‐Fused Dithiophene‐dione

A series of new organic semiconductors based on s‐indaceno[1,2‐b:5,6‐b′]dithiophene‐4,9‐dione was successfully synthesized and characterized. The electron withdrawing carbonyl group lowers the LUMO energy levels, leading to increased electronegativities, which is beneficial for high photo‐stability in air. The n‐alkyl substituted compounds, 1c and 1d , crystallize with the rigid coplanar systems packed into slipped face‐to‐face π‐stacks. Interestingly, 1c and 1d also show liquid crystalline behaviors, which give highly ordered molecular packing over large area.     

Ring‐opening Polymerization of L‐Lactide by an Anionic Cobalt(II) Aryloxide

The reaction of anhydrous CoCl₂ with NaOAr (ArO=2,4,6‐tri‐tert‐butylphenoxo) in THF at room temperature in 1:3 molar ratio afforded anionic cobalt aryloxide [Na(THF)₆][Co(OAr)₃] ( 1 ). The definite structure of this complex was characterized by X‐ray single crystal diffraction. It was found that this anionic aryloxo cobalt(II) complex could effectively initiate the ring‐opening polymerization of L‐lactide both in solution and in bulk, leading to high molecular weight poly(L‐lactide).     

162.5 MHz高频数字低电平控制监控系统设计与实现

中国科学院近代物理研究所自主研发的ADS 162.5 MHz高频低电平控制采用数字化技术实现,控制环路的参数设置、开闭环操作以及状态监测都通过监控系统实现。该系统基于以太网通讯,采用轻量化客户端-服务器端的工作方式,运行在上位机的客户端程序发送指令数据包,运行在高频数字低电平系统的服务器端响应指令,完成参数监测与控制。系统首先以Atera公司Stratix Ⅲ系列现场可编程门阵列(FPGA)开发板为基础,构建以Nios Ⅱ处理器和三速以太网接口为核心的服务器端硬件系统;其次基于Micro C/OSⅡ实时操作系统和轻量级TCP/IP协议栈,设计服务器端软件系统;最后利用MFC设计运行于上位机的客户端界面程序。经过长时间测试运行,该监控系统运行稳定可靠,TCP发送和接收吞吐率达到11.931 038 Mbps和8.117 624 Mbps。     

Image improvement based on sub-pixel post-integration for a staring imaging system in geostationary orbit

This paper proposes the post-integration technology based on sub-pixel image registration and image fusion to improve the signal-to-noise ratio （SNR） of remote sensing images without motion degradation caused by satellite vibration. A two-dimensional vibration system is set up to simulate satellite disturbance. Image sequences with different exposure times are captured using a high-speed CMOS camera. The displacement plots are compared with the motion data measured by the grating linear encoder. These plots indicate that the accuracy of the registration algorithm is better than 0.1 pixels. The sub-pixel image fusion shows an improvement in image quality, thus indicating that this technology is powerful for staring imaging systems in geostationary orbit.     

A novel sensitive biosensor for Ca2+ based on electropolymerized melatonin modified electrode

An electropolymerized melatonin modified glassy carbon electrode (EPMT/GCE) was prepared by electrochemically polymerizing of melatonin in a 0.04 mol l^?1 perchloric acid solution. In KCl solution, Ca²⁺ was found to perform a reversible complex reaction on the EPMT/GCE to produce a sharp complex adsorption wave. The configuration of the electropolymerized membrane was characterized by scanning electron microscope and various electrochemical techniques. Based on which, a novel sensitive Ca²⁺ electrochemical sensor was established. The peak current showed a linear relationship with Ca²⁺ concentration in range of 6.2 × 10^?7–1.0 × 10^?4 mol l^?1 with detection limit of 4.5 × 10^?7 mol l^?1. The developed electrochemical sensor has been used for determination of Ca²⁺ in body fluid.     

Fabrication of a new ECL biosensor for choline by encapsulating choline oxidase into titanate nanotubes and Nafion composite film

A simple strategy for encapsulating choline oxidase (ChOD) into the titanate nanotubes (TNTs) and Nafion composite film for choline sensing was proposed. Hydrogen peroxide, as the product of the redox enzymatic reaction, could enhance the ECL of luminol. Therefore, the substrates of corresponding redox enzymes could be detected indirectly through the determination of hydrogen peroxide in the luminol ECL system. Through this approach, it was found that ChOD could be fixed firmly into the TNTs contained composite film. TNTs would not only offer excellent photocatalytic activity toward luminol-H₂O₂ ECL system, but also provide a shelter for the biomolecules, such as redox enzyme to retain its bioactivity.     

In situ chemical synthesis of SnO2–graphene nanocomposite as anode materials for lithium-ion batteries

An in situ chemical synthesis approach has been developed to prepare SnO₂–graphene nanocomposite. Field emission scanning electron microscopy and transmission electron microscopy observation revealed the homogeneous distribution of SnO₂ nanoparticles (4–6 nm in size) on graphene matrix. The electrochemical reactivities of the SnO₂–graphene nanocomposite as anode material were measured by cyclic voltammetry and galvanostatic charge/discharge cycling. The as-synthesized SnO₂–graphene nanocomposite exhibited a reversible lithium storage capacity of 765 mAh/g in the first cycle and an enhanced cyclability, which can be ascribed to 3D architecture of the SnO₂–graphene nanocomposite.