光纤-混凝土复合体三维非线性有限元分析

对光纤-混凝土间的微观力学行为进行了分析。考虑了双接触面摩擦接触,通过试验确定了接触面力学参数;对光纤-混凝土复合体进行了三维非线性数值分析,得出光纤-混凝土复合体不同受载状况下微观应力应变分布状态及其接触面滑移状态,从理论上验证了光纤涂覆层对其传感灵敏度的影响及光纤布置方式的选择。     

两种用于界面测量的光纤传感器

本文报道了两种新型的光纤界面传感器;传光型反射式光纤界面传感器和传感型微弯式光纤界面传感器,讨论了影响传感器稳定性的环境因素及其消除方法。     

时分复用光纤光栅系统的边缘滤波解调与标定

为实现高空间分辨率和高测量精度的准分布式光纤光栅应变传感系统,研究了基于时分复用光纤光栅传感系统的解调和标定方法。将波分复用和时分复用技术相结合,得到两个低反射率光纤光栅的应变灵敏度分别为33.40με/mV和38.47με/mV,标定的非线性误差为2.8%。基于光纤光栅光谱边缘滤波技术,构建时分复用光纤光栅应变传感系统,提出复用光纤光栅应变的交叉传感解调算法,实验测试并解调两个光纤光栅的交叉传感数据。实验分析表明,单次测量传感系统的最大误差为18με,应变量大于100με时的传感相对误差小于5%,满量程600με的引用误差小于2%。     

光纤光栅传感特性的研究

通过对光纤光栅传感技术的研究,分析了光纤光栅的温度、应变传感特性,对光纤光栅的应变.温度传感特性进行了实验研究,论证了光纤光栅传感技术用于应变测量的可行性。     

应用光纤Bragg光栅测量混凝土结构内部应变

采用与土木工程施工特点相适应的传感器工艺与保护方法，将光纤Bragg光栅（FBG）埋于正在建设的呼兰河大桥预应力箱梁中，测量了预应力张拉过程中混凝土结构内部的应变变化。结果表明，FBG显示了良好的传感性能，能够监测混凝土内部应变状态，发挥出成活率高、绝对值测量和寿命长等优势，为建立结构健康监测系统奠定了基础。     

光纤检测钢管混凝土界面脱空模型的试验研究

通过分布式光纤传感技术可以实现对钢管混凝土界面脱空的检测，这对于这种组合结构的安全检测来说具有重要意义。本文讨论了脱空产生成因及分布式传感光纤实现脱空检测的机理，提出了在钢管中分布式传感光纤的布置形式，并进行了模型试验，得到重要规律，拟合出光衰减与脱空开度关系的曲线及公式。     

一种提高BOTDR系统信噪比的方法研究

提出了一种利用非线性反射镜提高布里渊光时域反射仪(BOTDR)系统信噪比的新型传感结构.通过将两根相同类型的传感光纤敷设在同一待测温度或应变环境下,结合光纤3 dB耦合器,可以形成非线性反射镜.利用非线性反射镜可以将传感系统输出信号的强度提高到只用一根传感光纤时的4倍,既能改善系统的信噪比及测量精度,也能提高传感系统的可靠性.     

FBG形状传感器应变传递与传感性能研究

为提高光纤布拉格光栅(FBG)形状传感器的形状重建精度,减小光栅点的重建位置误差,设计了一种FBG传感元件结构。通过建立传感元件应变传递力学模型,推导出平均应变传递率表达式,并结合传感元件有限元仿真模型,分析了相关结构参数对传感元件应变传递率的影响,将有限元仿真与理论计算结果进行对比,验证了理论模型的有效性。进而分析了应变传递率对传感系统形状重建精度的影响,得出当光栅点应变传递率保持在90%以上时,光栅点的重建位置误差将保持在0.08mm内。该研究表明,通过合理控制影响参数,可有效提高传感元件应变传递效率,减小传感系统形状重建位置误差,从而提高光纤形状传感器的形状重建定位精度。     

拱桥钢管混凝土无损检测技术研究

研究了钢管混凝土拱桥的无损检测技术，包括传统的超声波探伤和标志无损检测前沿发展方向的光纤传感技术。以巫峡长江大桥的工程实际检测为基础，对二者的检测结果进行了深入分析，并作了对比研究。着重分析了光纤传感监测网络的检测数据，该传感监测网络在国内首次确定了拱顶区域脱空位置、脱空开度(2～3mm)、脱空范围(整个监测区域)。并实现对钢管混凝土界面脱空的产生、发展的长期监测。     

FBG应变测试技术在混凝土内爆炸试验中的应用

在混凝土的内爆炸试验中,利用光纤光栅(FBG)传感技术对混凝土表面应变进行测量,获得了内爆炸荷载作用下的混凝土表面应变历史曲线,并对这些曲线进行了初步分析。分析结果表明试验采用的测量方法可行,同时也验证了重力作用对爆炸荷载混凝土表面应变分布的影响,且捕捉到混凝土试件与实验坑的碰撞响应。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks