摘要：large accelerator facilities require clocks and triggers with high accuracy to synchronize equipment and devices. A new femtosecond timing system was designed to meet the demands of new facilities. In this system, the radio-frequency signal is modulated in a continuous-wave laser carrier with frequency stabilization, and timing events are distributed in the same fiber. The phase drift is detected precisely, based on the principle of the Michelson interferometer. The phase drift is compensated with coarse and fine correctors afterward. We aim to realize the stable transmission of the RF signal and timing events for a long distance and duration, with the phase drift and additive jitter in femtoseconds. After the extension, the system will become a complete solution for the clock-and-trigger distribution of synchrotron radiation facilities, free-electron lasers, and other accelerators. The physics design, simulation analysis, and preliminary results are included in the paper.

摘要：A large-signal model for GaAs FET is derived based on its small-signal S parame-ters and DC characteristics. The harmonic balance algorithm is applied to analyze and optimizethe FET fundamental and harmonic oscillators, and the values of steady current are *** the solving process, a simplified CAD approach is used to obtain the parameters of matchingnetwork when the output power is maximum. Finally, a fundamental oscillator and a harmonicoscillator of Q-band are fabricated. The measurements show that the theoretical analysis andexperimental results are in good agreement.

摘要：Splitting water under large current density is essential for efficient large-scale production and commercial utilization of ***,the performance of the available electrocatalysts for hydrogen evolution reaction(HER)is far from satisfactory under large current density in alkaline *** we report a remarkably active and durable electrocatalyst,long and dense MoS2/Ni3S2 co-axial heterostructure nanowires on nickel foam(NF).Notably,it requires only 182 and 200 mV overpotential to achieve large current density of 500 and 1000 mA cm^-2,respectively,in alkaline solution,which are far superior to those of Pt/C-NF(281 and 444 mV)and the reported best non-noble metal catalysts(191 and 220 mV).The physical origin for this extraordinary HER performance is analyzed,which provides a useful guide for structure design of electrocatalysts to further improve their performance.

摘要：large Class(上帝类)是面向对象设计中的一种设计瑕疵。为了弥补传统large Class检测中使用面向代码结构度量的不足,提出基于潜在语义分析的平均概念相似性度量。根据源代码中提取的标识符和注释形成词-文档矩阵,在潜在语义空间下计算方法间的相似度,进而得到类的平均概念相似性;并将概念性度量与代码圈复杂度结合以对large Class进行识别。在开源的Code Smell检测数据集Landfill上进行实验,结果表明,与传统上使用结构信息对large Class进行检测相比,使用该方法时检测的准确率和召回率均得到了一定提升。

摘要：An approach is proposed to design decentralized state feedback H ∞ suboptimal controllers for LTI interconnected large scale systems. The parametrization theorem of decentralized robust state feedback controllers is developed in two steps and the design condition for the feedback gain is in the form of matrix inequalities. An iterative solution algorithm based on linear matrix inequality(LMI) techniques is proposed to obtain the decentralized feedback gain. The given examples are taken to show the application and the convergence of the algorithm.

摘要：针对并行计算特点,发展适用于流体并行计算的大涡模拟(large Eddy Simulation,LES)入流脉动直接合成方法。基于特征正交分解(Proper Orthogonal Decomposition,POD)型谱表示法合成入流面主要网格点脉动风速时程,采用有限元形函数空间插值获得入流面所有网格点风速时程,采用UDF(User Defined Functions)编程实现Fluent软件平台流体并行计算时合成的脉动风速时程读入及赋值。进行B类1:500缩尺比风场内宽高比1:6的单体方形截面高层建筑非定常绕流LES计算,将数值模拟所得风剖面、风速谱及结构风压系数统计值、自谱、相干性等,与刚性模型测压风洞试验及文献数值模拟结果比较。研究表明,该合成方法可较好模拟紊流风场,预测结构风荷载具有一定精度。

摘要：Considering generator rotor and valve by external disturbances for turbine regulating system, the nonlinear large disturbance attenuation controller and parameter updating law of turbine speed governor system are designed using backstepping method. The controller not only considers transmission line parameter uncer-tainty, and has attenuated the influences of large external disturbances on system output. The nonlinear con-troller does not have the sensitivity to the influences of external disturbances, but also has strong robustness for system parameters variation, which is because of the transmission line uncertainty being considered in internal disturbances. The simulation results show that the control effect of the large disturbance attenuation controller more advantages by comparing with the control performance of conventional nonlinear robust controller.

摘要：今天，玻璃已经不再被仅被视为一种装修材料，而是一种艺术媒介，例如杜尚的《大玻璃》（The large Glass），那种认为玻璃在20世纪更多被用于设计产品而不是艺术作品的认识，在上世纪80年代后被日益发展的后现代观点证明是很肤浅的。在新背景之下，玻璃越来越被视为颠覆过去经验的工具。

摘要：研究了小波包变换的硬件实现问题。针对现有小波变换硬件实现方案存在的适用范围窄、不适用于长支集小波和高分解级数等缺点，提出了基于双缓冲存储区的小波包变换硬件架构。其具有一定的可编程性和通用性，并以此为基础设计了通用小波包变换处理器芯片，它适于单片实现或作为各类应用系统的引擎单元。在完成芯片设计的同时，利用ＳＹＮＯＰＳＹＳ公司和ＡＬＴＥＲＡ公司的设计软件，以ＡＬ－ＴＥＲＡ公司的现场可编程门阵列（ｆｉｅｌｄｐｒｏｇｒａｍｍａｂｌｅｇａｔｅａｒｒａｙ，ＦＰＧＡ）器件为基础完成了对芯片的电路仿真。

摘要：New flat-oval groove rolling process of multi-direction deformation is proposed to manufacture ultra-fine grain bar. Application of new groove series can introduce uniform large plastic strain into whole cross section of the material, and meanwhile satisfy the requirements of shape and size. Principle of grain refinement, based on experimental research of small specimen, is that grain refinement of ferrite is mainly dynamic recrystallization when low-carbon alloy steel is at low temperature deformation. Relationship of grain size and z-factor is also obtained through experimental research, as well as ultra-fine ferrite grain less than 1 micron. To predict strain, shape, dimensions and grain size of the material in rolling process, numerical simulation model of the warm groove bar rolling process is established via nonlinear finite element method, and distribution of grain size of the final section is obtained via finite element subroutine. The result indicates that ultra-fine grain bar rolling can accomplish at low temperature region.