双膜片结构光纤光栅地震检波器低频特性的研究

提出了一种双膜片式的光纤光栅(FBG)地震检波器,此结构有效限制了检波器横向响应。对该检波器的纵向加速度灵敏度和幅频特性进行了理论分析,并指出了影响这种检波器纵向加速度灵敏度的因素。实验结果表明,该种检波器在5～200Hz频率范围内频响平坦,纵向加速度灵敏度为24.3pm/g,谐振峰在900Hz附近,与理论计算较好的吻合。     

基于光纤Bragg光栅的地震检波器的理论与实验研究

提出了一种新型的基于光纤Bragg光栅(FBG)的地震检波器。FBG地震检波器传感头由平面弹簧片、质量块和FBG构成。给出了该检波器的力学模型,理论推导与分析了该检波器的幅频特性和加速度灵敏特性,并讨论了影响该检波器灵敏度的主要因素。实验结果表明,该检波器具有良好的线性度、稳定性和耐受性;检波器的频率响应范围为10～140 Hz,传感器灵敏度为25.9pm/g,共振频率为167 Hz,较符合理论值;最高可检测加速度值大于30g。     

基于3×3相位解调的光纤地震检波器研究

针对基于3×3相位解调的光纤地震检波器展开研究.利用基于最小二乘法的椭圆拟合法和微分交叉相乘算法,实现基于3×3相位解调的光纤地震检波器的两路输出信号的归一化,减小光纤3×3耦合器的非对称性和激光器的功率波动对光纤地震检波器的影响,解调出光纤地震检波器的相位,实现振动信号的准确还原.实验采用对比法测试了基于3×3相位解调的光纤地震检波器的性能,其灵敏度为320 rad/g@100 Hz,在5～400 Hz频率范围内的波动约为0.7 dB.该研究能够很好地应用于石油、天然气等地质勘探、地震监测以及周界安防等领域.     

迈克尔逊干涉型加速度地震检波器集成芯片

提出了一种新型的迈克尔逊干涉型混合集成光学加速度地震检波器。以尺寸为38mm×6mm×2mm的X切Y传LiNbO3晶体为基底,详细分析并设计了迈克尔逊干涉芯片的双Y分支波导、相位调制器和偏振器。对成功制作的迈克尔逊干涉芯片进行了通光测试,并对检测器进行了测试。结果表明,检波器及芯片性能良好,振动与检波器输出信号吻合良好。该检波器系统的主要设计参数为:自然频率3549Hz,相位检测灵敏度ΔΦ/a为1.1×10-2rad/m/s2,工作频带0～1065Hz。     

高灵敏度大带宽光纤光栅微地震检波器研究

提出了一种基于铰链连接的光纤布拉格光栅(FBG)微地震检波器,理论分析了检波器的灵敏度和谐振频率,讨论了光纤连接位置和质量块转动惯量对灵敏度和谐振频率的影响,提出了获得高灵敏度和大带宽的优化方法,并采用有限元方法进行了模拟验证。制作了检波器样品,并采用商用解调仪进行了测试,获得了高于40pm/g的灵敏度和1kHz的谐振频率,系统的等效噪声低于0.1mg/Hz,表明本文检波器可应用于微地震监测中的高频微弱地震信号探测。     

基于杠杆放大机构的光纤光栅中高频地震检波器

为解决在中高频地震信号勘探检测中,检波器存在的高固有频率与低灵敏度的矛盾,提出了一种基于杠杆放大机构的光纤光栅中高频地震检波器。在惯性质量块的一端链接杠杆放大机构,光纤光栅以两点式封装法竖直固定在杠杆的放大端与基底之上。杠杆放大机构可以在检波器的输出端产生机械放大,增加光纤光栅的轴向应变,增大对地层中微弱中高频信号的响应,从而提高检波器的灵敏度。同时检波器的机械结构使用一体化加工工艺,可提高机械结构的刚度与稳定性。实验测试表明,该检波器的固有频率为526 Hz,在20—260 Hz的频率范围内,灵敏度为119.108 4 pm/g,同时具有良好的横向抗干扰性能。这为中高频段载震检波器的研究提供了一定的技术思路和方向。     

激光多普勒检波系统的研究

为了进一步提高地震检波器的指标,研究了激光多普勒测量方法和微弱信号检测技术等,设计出了一种LD做光源的差动式激光多普勒检波系统,此系统采用高斯光束聚焦、大口径透镜接收,能接收到很强的多普勒信号,并且具有高的空间分辨力,同时,采用声光调制技术及锁相放大技术,提高了信号的信噪比,其结构简单、紧凑,装调方便,光能利用率和空间分辨力高,可测频率范围为0.5Hz～1000Hz;振幅范围为2μm～5mm;频率测量精度为0.6%;振幅测量精度为1%。     

基于轴承式杠杆机构的光纤光栅高频地震检波器设计

针对目前高频段信号波的研究相对薄弱的问题,设计了一种基于轴承式杠杆机构的光纤光栅高频地震检波器。该检波器以杠杆机构和其中的轴承支点为创新点,使用仿真软件对检波器模型进行了静态结构分析、模态分析和谐波响应分析。仿真结果表明：该地震检波器的仿真灵敏度为64.588 pm/g,仿真固有频率为1 638.5 Hz;调整杠杆放大机构动力臂与阻力臂长度比例和摆线铰链的切割半径,得到检波器的仿真固有频率为1 204.4 Hz,仿真灵敏度为75.56 pm/g。     

音箱的设计.制作与调校(三)——扬声器的原理与性能

四、箱体的作用 品质优良的扬声器单元是 保证高保真重放的必要条件,但不是充分条件,即使有了性能优良的信号源和功率放大器也是这样。比如,要获得一个重播频率范围为35～20000Hz的放声装置,假设信号源和功率放大器都能轻易满足这个要求,那么即使你选择一个谐振频率f_0为28Hz,有效频率范围为28～4000Hz的低音扬声器和有效频率范围为2500～25000Hz的优质高音扬声器,把它们与放大器连接在一起。我们会发现,它们根本达不到我们的要求:一是频率范围达不     

NE567音频译码锁相环的分析与应用

NE567是带有同步幅度检波器和功率输出级的高稳定度单片集成锁相环路。工作频率范围宽(0.01Hz～500kHz)、中心频率稳定度高(35±60ppm/℃)、捕捉带宽、容易控制(达14％f_0),对带外信号和噪声的抑制度高(+6dB),具有100mA灌电流逻辑输出能力、外围电路简单等特点。本文介绍NE567在通信中的应用,重点介绍NE567作2600/2100Hz信令接收的应用。     

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.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

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.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.