人工神经网络和电阻抗谱法压电材料快速表征

压电材料作为重要的功能材料,广泛应用于社会的各领域,但其弹性常数的偏差会导致应用过程中出现错误的设计,弹性常数的正确表征对压电器件的正确设计尤为重要。与其他测量方法相比,电阻抗谱仅需要阻抗分析仪即可实现测量,通过测量阻抗谱反演获得压电材料的弹性常数。传统电阻抗谱法通过不断修正材料参数,使得测量阻抗谱和计算阻抗谱最大程度吻合,该过程需要多次迭代,计算量大,耗时较长。该文提出采用神经网络建立阻抗谱到弹性常数的正向模型,测量得到阻抗谱后仅需一次正向计算即可得到弹性常数。使用Comsol和Matlab联合仿真建立数据集,引入丢弃法避免模型过拟合,利用Pytorch建立模型,经过训练后,最大谐振频率偏差从初始2.8%降至0.8%。该技术为压电材料弹性常数精密测量提供可靠的理论与实践途径。     

电极激励超声谐振谱压电材料定征技术

超声谐振谱（RUS）是一种压电材料单样品定征技术,避免了多样品造成的结果不自洽问题。现有的谐振谱激励方法常使用超声换能器定点激励 拾取,需要有复杂的测试装置。该文提出了一种电极激励 拾取法来获取压电谐振器的超声谐振谱,该方法测试装置简单,同时还可获得模态振型的对称特性,避免了反演过程中峰丢〖JP2〗失和错峰拟合。基于现场可编程门阵列(FPGA)技术搭建了压电谐振器分组扫频激励电路,通过电荷放大器拾取谐振峰。结果表明,通过Levenberg Marquardt算法可完成测试频谱和计算频谱的匹配,成功获得了优化后压电材料参数。     

一种由压电双晶片测量压电常数d31的方法

提出了一种新的测量方法 ,由一种实用元件——压电双晶片测量压电材料的压电常数 d31的方法。这种测量方法不同于通常的由标准试样测量压电材料参数的方法。文中给出了测量原理、测量装置及由一种 PZT样本的测量结果 ,并同时给出了 IEEE标准测量方法的结果。理论和实验结果表明 :这种新的测量方法是可行的。     

一种电压电双晶片测量压电常数d31的方法

提出了一种新的测量方法,由一种实用元件－压电双晶片测量压电材料的压电常数ｄ３１的方法。这种测量方法不同于通常的由标准试样测量压电材料参数的方法。文中给出了测量原理、测量装置及由一种ＰＺＴ样本的测量结果,并同时给出了ＩＥＥＥ材料测量方法的结果。理论和实验结果表明：这种新的测量方法是可行的。     

电气和电子工程用材料科学

TB43,TM936 00010032用转矩仪测皿薄膜磁各向异性的研究/张宝峰,曹文斗,魏立锋(天津大学)11仪器仪表学报一1 999,20(4)一398一400该文讨论由转矩仪测量薄膜材料磁各向异性的一个新方法,当单轴各向异性膜材料的本征易轴随机取向与膜平面的夹角为a时,通过测量本征易轴和形状各向异性易轴合成的表观易轴的取向(与膜平面间的夹角)以及常数值,就可以计算得到膜材料的本征磁各向异性常数和易轴的空间取向.图4参6(木)利用高能离子注人技术系统地研究了不同剂量、不同种类离子注入对C60薄膜结构的影响,并利用Raman光谱对其结构进行分析.结果表明:…     

压电材料复参数的非线性最小二乘法估计

将压电材料参数作为复数考虑，对分析压电材料性能有着实际意义。该文从曲线拟合的思想出发，运用非线性最小二乘法(高斯-牛顿法)来估计压电材料复参数，仿真结果显示，估计值与真实值比较接近，算法的收敛性较强，是压电参数测量的一个实用方法。     

压电晶体导纳圆测量仪的设计与实现

测量压电晶体的导纳圆可以得到3对频率，用这些频率可分析超声马达、换能器以及压电器件的振动模态及其频率特征。采用DDS技术设计并实现了压电晶体导纳圆测量仪。实际测量结果表明，该仪器的测量精度较高，运行稳定可靠。该文主要介绍导纳圆的测量原理，并讨论了其中硬件与软件的关键技术环节。     

多层压电变压器基本工作特性的研究

采用阻抗分析仪等测量仪器系统地测量了多层压电变压器的输入阻抗特性、升压比和输入输出特性，为多层压电变压器的设计和研究提供了依据。     

用动态位移响应测量压电常数的方法

根据基本压电方程了压电陶瓷晶片面内受迫振动的计算公式,并结合共振实验,提出了一种直接测量压电陶瓷晶片的压电常数的方法。与传统的线路传输压电常数测量方法相比较,本方法具有许多优点。由于减少了中间环节,测量结果的精度也得到了提高。     

矢量信号分析仪在测量CDMA通信系统中的应用

介绍了矢量信号分析仪的基本原理，给出了利用矢量信号分析仪测量CDMA信号的具体方法，并与利用扫频分析仪等仪器进行测量的优劣性作了相应对比。     

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.     

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.     

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.     

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.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

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.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

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.