一维六方准晶纳米板中Lamb波特性研究

准晶纳米结构在工程中经常承受以弹性波为代表的动态工作载荷，为深入研究其动态失效机制，研究了一维六方准晶纳米板中Lamb波的波动特性。基于修正的偶应力理论，推导出Bak模型下Lamb波的波动控制方程，使用勒让德正交多项式方法 (LOPM)求解该动力学方程，计算得到其频散曲线和位移分布。研究了声子场和相位子场尺寸效应、声-相耦合效应对波动特性的影响。结果表明：尺寸效应使声子模态和相位子模态相速度增大；声-相耦合效应显著地增大了声子模态中的相位子位移振幅和相位子模态中的声子位移振幅。研究结果为准晶纳米结构的设计和无损检测奠定了一定的理论基础。     

偏振无关的可变纯相位延迟器研究

提出了一种由快轴保持正交方位放置的两片相同的液晶可变相位延迟器构成的可变纯相位延迟器结构设计.利用琼斯矩阵,从理论上推导了该结构在任意偏振光入射条件下,出射光偏振态与入射光偏振态保持一致.实验上,在两片液晶可变相位延迟器所加电压分别为1.55V和1.49V时,分别测量了入射光和出射光的偏振态,表征偏振态的入射光和出射光的Stokes参教基本一致.上述两者结果都表明,该结构具有较好的纯相位调制特性,并给出了控制电压在1～2.7V范围时的相位变化.     

子象素精度测量方法及其应用综述

本文对子象素精度测量的几种方法及其应用作了分析和讨论。这几种方法包括：几何方法，迷是一种利用目标的几何特性是得到子象素精度的测量数据的方法；内插，包括互相关内插，相位相关内插，以及亮度内插等；相关，主要用于测量一个已知目标在一个图象中的位置，或者用于一对图象之间的地准；边缘检测，可以进行位置测量，或者周长面积的测量，如掩模算子，矩匹配法等。     

基于Duffing振子的BPSK载波信号检测方法研究

针对低压配电网具有噪声干扰强、信号衰减大等问题,提出了用Duffing振子来检测BPSK载波信号的新方法.Duffing振子对微弱信号敏感,信号的不同相位将引起系统在混沌态与大尺度周期态之间的相变,该方法就是利用载波信号的相位引起的Duffing振子的相变,通过对该相变的判别来检测载波信号的相位信息.同时还分析了Duf...     

生产过程和工艺技术用的干式三级前级抽气系统

目前已开发出一种干式抽气系统，它与今天已面市的前级真空泵（爪形转子）罗茨转子原理）不同，具有许多明显的优点，这种抽气系统的两个转子是通过一齿轮对作相对旋转，转子几何开关特点是，其中一各转子只起抽运介质的作用另一个转子则是起关闭进，出口截面（控制转子）作用。这种转子型线在几何形状和分级方面起到极好的相互调节作用。图１是从吸气到排气的抽气相位图，示出三个抽气阶段中的一个抽气相位，理论抽速可用（Ｖ１＋Ｖ     

SAR干涉测量数字高程模型提取与高程误差校正

介绍了基线几何参数的估计、干涉相位图生成、干涉相位去平、基线几何参数优化算法、高程解算等原理。利用在中国内蒙古自治区获取的一对ＳＩＲ－Ｃ／Ｘ ＳＡＲ Ｌ波段干涉测量数据研究了干涉测量数据处理方法,对整景ＳＡＲ数据进行了处理,生成了相应地面范围的数字高程模型。在试验区地形图的辅助下,分析了利用粗略基线几何参数求算高程产生误差的原因,实现了基于ＧＣＰ的基线几何参数优化算法。利用控制点进行校正后,数字高     

基于双目立体视觉偏折术的标定

相位测量偏折术(PMD)是近几年在光学测量领域内普遍使用的一种非接触式的高精度测量方法,而系统几何标定是相位测量偏折术获得高精度测量的先决条件。由于LCD显示屏位于摄像机的视野之外,增加了标定的困难,本文提出的基于双目立体视觉的相位测量偏折测量系统,通过姿态转换几何标定方法进行系统标定,标定左右两个摄像机与LCD显示器之间的相对位置关系,并通过实验验证了该标定方法的可行性和准确性。     

指数型回归模型参数置信域的曲率表示

本文从几何观点研究了指数型回归模型参数和子集参数的置信域问题，由于许多回归模型，诸如正态非线性回归，指数族广义线性模型和广义非线性模型等均可视为本文模型的特例，因此，本文的研究推广和发展了现有文献中的许多结果（如（２），（４），（５）等）。     

基于微分法的新相位测量轮廓术

在相们测量轮廓术中，为了得到真实相位值，必须进行相位解包裹处理的繁琐过程，为此提出一种可以直接获得真实相位值的新算法。这种算法的原理是空域中的微分（一阶）等效于频域中乘以一个线形因子，由此得到相位微分与光强的关系，求出相位的微分值后将其积分就获得相位的真实值。计算机仿真显示该方法确实有效可行。     

基于相位调整法实现蛇形机器人避障功能的研究

为了提高蛇形机器人在实际环境中的实用性,研究了蛇形机器人的避障功能,并提出了一种基于相位调整的蛇形机器人避障方法。该方法用安装在蛇形机器人头部的红外避障传感器模块检测前方是否有障碍物,若有障碍物,则用相位调整法改变蛇形机器人每个关节的步态相位来控制蛇形机器人的蜿蜒运动以实现转弯,从而避开障碍物。而且应用红外传感器来感知障碍物的几何特性,若感知到大型障碍物,机器人蜿蜒运动行进采用顺障策略实现避障功能,若感知到小型障碍物,采用绕障策略。该研究可为推进蛇形机器人的实用化提供技术储备。     

Properties of Spinor Bose Condensates

We analyze the ground state structure and low energy dynamics of an f=1 spinor condensate. We show that there are distinct time scales governing the spin-mixing process in spinor condensates and analyze them using algebraic, semiclassical, and numerical approaches. We find that the dynamics is sensitive to the relative phase, particle number distribution among the spin components, and the total particle number in the condensate. We further find that complicated structures develop in the densities during the evolution. We also investigate the dynamics under the action of external magnetic fields and uncover an intriguing set of phenomena like stochastization in spin populations, metastability in the spin component distribution, and dynamic localization in spin space.     

Direct Protein Detection in the Sample Solution by Monitoring Rotational Dynamics of Nickel Nanorods

The feasibility of a recently introduced homogeneous immunodiagnostic approach to directly detect analyte binding by optical observation of the hydrodynamic properties of magnetically rotated nanorods (“PlasMag”) is demonstrated experimentally. Specifically, it is shown that the phase lag of the long axis of nickel nanorods (magnetic core parameters: length 182 nm, diameter 26 nm) with respect to externally applied rotating magnetic fields significantly increases on the adhesion of bovine serum albumin (BSA) protein to their surfaces. To validate these results, the amount of bound protein molecules is independently determined by analysis of the electrophoretic mobility of the nanorods. Furthermore, the data also demonstrate the applicability of recently developed empirical models based on numerical solutions of the Fokker‐Planck equation for describing the dynamics of magnetic nanoparticles in rotating magnetic fields.     

The magnetization reversal process in spin spring magnets

The behavior of soft magnetic films in spring magnets, as a function of the intensity and orientation of an external magnetic field, is described in the framework of spin-polarized non-collinear electronic structure calculations. As experimentally observed, the critical intensity of the external field required for the onset of the non-collinear spiral formation depends on both the thickness of the soft magnetic phase and the orientation of the field. The spin spiral structure undergoes a change of chirality in rotating fields. Our theoretical approach opens new prospects for investigating the response of other nanostructures to external magnetic fields beyond usual phenomenological models.     

Barkhausen Noise Measurement System Using a Three-Pole Probe

In the present study, a three-pole probe is proposed for measurement of Barkhausen noise (BN). A system was constructed for forming a magnetic field using the three-pole probe and succeeded in forming rotating magnetic fields of the same amplitude in all directions and arbitrary orientated stationary alternating magnetic fields. Furthermore, a BN measurement system was constructed and used to measure the BN of a grain-oriented electrical steel sheet. The results show that the BN exhibits a large output in the direction of the easy magnetization axis of the specimen, and it is demonstrated that the BN measurement result using the rotating magnetic field formed by the three-pole probe is reliable.     

A new proposal on field-access bubble drives

This paper describes the results of driving bubbles with various rotating magnetic fields and proposes a triangulardrive method. This method is expected to furnish high power efficiency and simplification of the drive electronic circuit in practical magnetic-bubble memories.     

Analysis of magnetic fields of a delta type shunt reactor

A model is given and a periodic boundary condition is adopted to analyze magnetic fields of a delta type shunt reactor. An approximate three-dimensional finite-element method that combines some axisymmetric fields and a two-dimensional field is then applied. It is found that the flux in the yoke concentrates on the part that is near the legs. The flux density heightens as the legs is approached, and rotational magnetic flux occurs in the parts joined by a leg and the yoke. All flux density waveforms contain mainly third harmonics. It is found that there is rotating flux in the yoke, which causes increased core losses     

Magneto-optical control of bright atomic solitons

Abstract

In previous work we showed that bright atomic solitons can arise in spinor Bose-Einstein condensates in the form of gap solitons even for repulsive many-body interactions. Here we further explore the properties of atomic gap solitons and show that their internal structure can be used to both excite them and control their centre-of-mass motion using applied laser and magnetic fields. As an illustration we demonstrate a nonlinear atom-optical Mach-Zehnder interferometer based on gap solitons.     

Saturation magnetostriction measurements of magnetic thin films under high magnetic fields

Saturation magnetostriction measurements of magnetic thin films have been studied using a system equipped with a motor driven electromagnet and a laser displacement meter. A new method to reduce the errors caused by applied rotating magnetic field is proposed for high-sensitive and accurate measurements of saturation magnetostriction. It is shown that accurate measurements are possible for magnetic fields up to around 1 kOe, by extracting the 2nd harmonic output through Fourier analysis as a function of applied rotating magnetic field and then by taking the extrapolation of 2nd harmonic output to zero magnetic field. This method is applied to measure a saturation magnetostriction of single-crystal fcc-Co(111) film and the value of − 30 × 10^− 6 is obtained.     

Implicit–explicit time integration DRBEM for generalized magneto-thermoelasticity problems of rotating anisotropic viscoelastic functionally graded solids

A numerical computer model based on the dual reciprocity boundary element method (DRBEM) is extended to study the generalized theories of magneto-thermoelasticity problems in a rotating anisotropic viscoelastic functionally graded solid placed in a constant primary magnetic field acting in the direction of the z-axis and rotating about this axis with a constant angular velocity. In the case of plane deformation, a predictor–corrector implicit–explicit time integration algorithm was developed and implemented for use with the DRBEM to obtain the solution for the displacement and temperature fields in the context of the Green and Naghdi theory of type III. A comparison of the results is presented graphically in the absence and presence of magnetic field. Numerical results that demonstrate the validity of the proposed method are also presented graphically.     

Rotating light fields of an azimuthally polarized light beam generated by two-belt spiral phase modulation

The tightly focused light fields of an azimuthally polarized light beam through a two-belt spiral phase plate were investigated. The focused light fields are presented in accordance with vectorial diffraction theory. The results show that a rotating light field with different intensity patterns can be produced by altering the azimuthal polarization state and modulating the two-belt spiral phase. A concurrent change in spiral handedness in the two-belt phase plate causes the rotation to occur along the direction of propagation, and the relative angular offset in the two-belt spiral phase plate can be exploited to rotate the light fields. The proposed method is useful for engineering the intensity distribution near the focal plane and related applications.