结构安定分析的Galerkin边界元方法

基于Melan静力安定定理,利用Galerkin边界元方法建立了多组交变载荷作用下结构安定分析的下限计算格式.在给定载荷域的载荷角点所对应载荷作用下,采用Galerkin边界元法计算相应的虚拟弹性应力场,并且利用结构在Galerkin边界元弹塑性增量计算中同一增量步中不同迭代步之间的应力差作为自平衡应力场的基矢量,通过这些基矢量的线性组合构造了自平衡应力场,大大降低了所形成的数学规划问题的未知变量数.并通过复合形法对非线性规划问题直接进行求解,得到了结构在交变载荷作用下的下限安定乘子.计算结果表明,所采用的方法具有较高的精度和计算效率.     

考虑材料循环塑性的疲劳裂纹扩展模拟

提出了一种考虑材料循环塑性性能的研究疲劳裂纹扩展与闭合行为的有限元模拟方法．对所选用的循环塑性本构关系进行了基本实验检验．探讨了在疲劳裂纹扩展有限元分析中网格尺寸的影响，给出了网格优化准则．研究了在循环硬化条件下考虑裂纹合效应时裂纹面张开廓形、裂纹尖端应力、应变场和正反向塑性区的演变规律．对于循环硬化和不同循环应力比Ｒ等因素对裂纹张开应力水平的影响也作了考察     

Proteus仿真软件在集成电路应用课程教学中的实践

集成电路应用课程是高职院校电子类专业的一门专业课。Proteus软件下的虚拟开发环境,具有不受实训场地限制,有利于促进课程的实践教学的特点。本文介绍了使用Proteus软件进行课堂教学、实训和课程设计等各实践教学环节中的应用实例及体会。     

A Fast Decoupled Nominal 2-D Direction-of-Arrival Estimation for Coherently Distributed Source

In this paper, we consider the problem of the nominal 2-D (azimuth and elevation) direction-of-arrival (DOA) estimation for coherently distributed source. This new approach is based on the rotation matrices of three parallel uniform linear arrays as deduced, which has decoupled the nominal 2-D DOA from those of angular spreads. The estimator makes use of the eigenvalue decomposition to beamspace data to estimate the nominal elevation DOA. And then using a new cross-correlation matrix, the nominal azimuth DOA estimates are decoupled from the elevation estimates and can be obtained with no searching. The proposed algorithm has lower computational complexity particularly when the radio of array size to the number of source is large, at the expense of negligible performance loss. Simulation results verify the effectiveness of the proposed method.     

By-design molecular architectures via alkyne metathesis

Shape-persistent purely organic molecular architectures have attracted tremendous research interest in the past few decades. Dynamic Covalent Chemistry (DCvC), which deals with reversible covalent bond formation reactions, has emerged as an efficient synthetic approach for constructing these well-defined molecular architectures. Among various dynamic linkages, the formation of ethynylene linkages through dynamic alkyne metathesis is of particular interest due to their high chemical stability, linearity, and rigidity. In this review, we focus on the synthetic strategies of discrete molecular architectures (e.g., macrocycles, molecular cages) containing ethynylene linkages using alkyne metathesis as the key step, and their applications. We will introduce the history and challenges in the synthesis of those architectures via alkyne metathesis, the development of alkyne metathesis catalysts, the reported novel macrocycle structures, molecular cage structures, and their applications. In the end, we offer an outlook of this field and remaining challenges.

The recent synthesis of novel shape-persistent 2D and 3D molecular architectures via alkyne metathesis is reviewed and the critical role of catalysts is also highlighted.     

μC/OS-Ⅱ中最高优先级查找算法分析

μC/OS-Ⅱ内核是采用占先式调度方式的实时内核,保证最高优先级任务一旦进入就绪态,就能立刻得到CPU的使用权,减少系统响应时间,从而保证系统实时性。文中阐述μC/OS-Ⅱ内核如何通过查表法快速找出就绪态中优先级最高的任务,并详细分析了就绪态中最高优先级任务调度方法和查找算法,最后给出了相应的例子。     

低强度He-Ne激光血管内照射改善血液流变学性质机理探讨

ILIB提供的生物能量改善红细胞的聚集性，ILIB提供的生物信息和生物能量调整红细胞的变形性，从而改善血液流变学性质。     

Design of Down Scalers in Mixed-Signal GHz Frequency Synthesizer

An optimized method is presented to design the down scalers in a GHz frequency synthesizer.The down scalers are comprised of dual modulus prescaler (DMP) and programmable & pulse swallow divider,different methods of high frequency analog circuit and digital logical synthesis are adopted respectively.Using a DMP high speed,lower jitter and lower power dissipation are obtained,and output frequency of 133.0MHz of the DMP working at divide-by-8 shows an RMS jitter less than 2ps.The flexibility and reusability of the programmable divider is high;its use could be extended to many complicated frequency synthesizers.By comparison,it is a better design on performance of high-frequency circuit and good design flexibility.     

Quantum Effects of a Dissipative Mesoscopic Circuit with Mutual Inductance

We study the quantum fluctuations of the charge and current of two L-C dissipative mcsoscopic circuit withthe mutual inductance in the vacuum state. Our results show that the system state will evolve to a squerzcd coherentstate under the effect of external source. We find that the squeezing amplitude parameter is relative to the parametersof circuit and the mutual-inductance coefficient in the existence of dissipation. Whcn the circuit has no dissipation orthere is complete coupling between two meshes, the squeezing amplitude parameter only depends on the capacitance'sratio.     

利用匹配追踪算法提取变电站内路径损耗参数

为了衡量变电站内电磁环境对无线通信设备的干扰,尤其是对无线信道的干扰,采用频域测量方法在110 kV和220 kV变电站内分别对430 MHz和470 MHz通信频段电磁波路径损耗进行了测量。针对变电站内电磁环境相对复杂的情况,提出了一种利用匹配追踪算法滤除噪声,提取路径损耗参数的方法。根据测量信号的特征,构建了与测量信号匹配而对噪声不敏感的高斯脉冲原子库。与常规的Gabor原子库相比,基于构建的高斯脉冲原子库的匹配追踪算法比传统的基于Gabor原子库的匹配追踪算法运算速度要快3~4倍,提高了匹配追踪算法的运算速度,减少了计算时间,获得了较好的降噪和信息提取的效果,为变电站内布置无线通信设备提供了理论依据和指导意义。