Measurement of creep of optical fiber by a low coherent white light double interferometer system

The creep properties of optical fiber used in fiber optical sensors were studied in this paper.A low coherent white light double interferometer system was designed and calibrated and the creep deformations of optical fibers under static and cyclic loadings were measured with this device.The research results showed that polymer coated optical fibers crept at the beginning when they were under static or cyclic load.As the number of the cyclic loading or the static loading times increased the creep tended to s...     

Global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback

This paper presents both analytical and numerical studies on the global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback. Based on a detailed analysis of the stability switches of the trivial equilibrium of the system, the stability charts are given in a parameter space consisting of the time delay and the feedback gains. The center manifold reduction and the normal form method are used to study Hopf bifurcations with respect to the time delay. To gain an insight into the pe...     

基于频散特性的杆中超声波传播仿真

针对超声实时在线检测中缓冲杆应用的局限性,以无限长杆的频散特性为理论基础,利用有限长杆的端面边界条件,分别以应力关系和应变关系为系统函数,建立了超声波在有限长杆中传播的系统模型。通过在杆端面施加激励,借助系统传输模型,获取回波信号,并与实验进行对比,验证该方法的正确性。同时得出了超声波在有限长杆中传播产生的多次回波的重复周期与杆半径之间成正比的关系。     

New cooperative frequency domain differential modulation and demodulation

An innovative method of cooperative frequency domain differential modulation and demodulation is presented.This method applies the prior knowledge of channel propagation to selecting the variable differential length and carrying out frequency domain modulation.This strategy optimizes the design of system parameters to effectively improve the anti-interference ability of the differential system in time-varied multipath channel circumstance without making the execution more complicating.The simulations and comparisons demonstrate the proposed method is effective,and the results show that it is especially suitable for the fading channel with strong propagation and fast time-variation.     

含有{M[P4Mo6O31]2}夹心型磷钼酸盐构筑块的水溶性多酸化合物的合成与表征

采用水热方法合成了一个新的磷钼酸盐化合物，并通过元素分析、红外、紫外、循环伏安和单晶X射线衍射分析等手段对其进行了表征。单晶结构解析结构表明，该化合物的阴离子{Na[Mo₁₂O₂₄(OH)₆(PO₄H)₂(PO₄H_3/2)₂]}^6- 由2 个{Mo₆P₄O₃₁} 单元和一个八面体配位的金属钠离子共价组装形成，具有夹心型结构。该化合物是目前为止获得的第一个含有孤立M[Mo₆P₄O₃₁]₂ 夹心结构的水溶性多钼磷酸盐。该水溶性化合物将会作为一个基本的反应原料和基本构筑单元合成组装出更多结构新颖、性质丰富的新型多钼磷酸盐。     

Magnetocaloric effect in Er-Al-Co bulk metallic glasses

A series of Er-Al-Co bulk metallic glasses (BMGs) have been prepared by the copper mold casting method. The glass forming ability and magnetocaloric effect (MCE) for these alloys have been investigated. The second-order magnetic transition from para-magnetic to ferromagnetic states takes place at about 9 K. These BMGs exhibit excellent MCE because of their large effective magneton number; Er56Al24Co20 BMG has a maximum entropy change and refrigeration capacity of 16.06 J kg-1 K-1 and 546 J kg-1,respectively...     

SP 3D在硫磺回收项目中的定制与开发应用

采用三维工厂设计系统SP 3D对某硫磺回收装置项目开展布置设计的过程中,通过定制、扩展和二次开发等工作,达到完善设计标准数据库和更加智能化工作的目的。举例介绍了管架数据库扩展、图面定制二次开发和地下管线交叉点报告等工作,展示了专业知识与专业软件的深入结合,可以提升设计效率和降低设计错误,从而提高了工程设计质量。     

浓度对薄凹液层胶体悬浮液干燥花样形成的影响

研究了不同浓度下厚度较薄的凹液层胶体悬浮液干燥过程及花样, 利用照相机实时拍摄不同浓度下胶体悬浮液的干燥过程. 结果表明随着浓度的增加, 最终干燥花样圆环宽度增加, 而数目明显减少; 干燥过程分为5阶段, 其中包含两阶段马兰哥尼对流; 对流能够影响悬浮液内胶体颗粒的自组装和薄膜形貌, 第一阶段对流导致薄膜边缘厚、中心薄, 第二阶段对流伴随接触线的钉轧-滑移运动, 导致多重宽环花样形成.     

External synchronization of two dynamical systems with uncertain parameters

External synchronization is addressed as two or more dynamical systems with synchronous motions, which is also regarded as master-slave system. In this paper, two dynamical systems, one employs a hysteretic term to model the friction phenomenon, the other involves a hardening stiffness component with the third order of displacement due to flexible deformation, are controlled to converge to the same trajectory. The control strategy is extended from feedback control for all parameters known to adaptive contro...     

Parallelization and Performance Optimization on Face Detection Algorithm with OpenCL: A Case Study

Face detect application has a real time need in nature. Although Viola-Jones algorithm can handle it elegantly, today’s bigger and bigger high quality images and videos still bring in the new challenge of real time needs. It is a good idea to parallel the Viola-Jones algorithm with OpenCL to achieve high performance across both AMD and NVidia GPU platforms without bringing up new algorithms. This paper presents the bottleneck of this application and discusses how to optimize the face detection step by step from a very nave implementation. Some brilliant tricks and methods like CPU execution time hidden, stubbles usage of local memory as high speed scratchpad and manual cache, and variable granularity were used to improve the performance. Those technologies result in 4-13 times speedup varying with the image size. Furthermore, those ideas may throw on some light on the way to parallel applications efficiently with OpenCL. Taking face detection as an example, this paper also summarizes some universal advice on how to optimize OpenCL program, trying to help other applications do better on GPU.