基于相位凝固技术的激光反馈干涉术

针对激光反馈干涉术,提出基于相位凝固技术的调制解调方法,用以提高位移测量的分辨率,并设计了利用相位调制器进行调制的位移测量系统.利用调制器进行外腔相位调制,采集调制相位相对固定的干涉光信号,通过解调重构得到被测的位移信息.进行了信号调制、采样、重构技术的研究以及误差分析,并通过仿真验证了方法的可行性.结果表明,采用5点相位凝固采样技术,测量准确度可以达到λ/20.此方法可提高激光反馈干涉术的测量分辨率,实现信号实时采集处理,可用于位移的实时测量.     

Amplitude modulation of a low-coherence source, applications to distance and dynamic displacement sensing

The possibilities of the radio-frequency amplitude modulation of a low-coherence source for distance and displacement measurements are discussed. This intensity-based method, used within a Michelson interferometer, is a novel alternative to perform dynamic deformation measurements. The theoretical background is presented, together with the experimental verification of the principle. Besides, the results of the first quasi-dynamic tests are shown and the perspectives of the technique discussed. This method is specially useful for the dynamic monitoring of civil structures, where large measurements bases are needed. Furthermore, the application of the amplitude modulation for distance measurements is demonstrated experimentally.     

Displacement structure approach to q-adic Chebyshev–Vandermonde-like matrices

In this paper, a new class of so-called q-adic Chebyshev–Vandermonde-like matrices over an arbitrary non-algebraically closed field is introduced. This class generalizes both the ordinary Chebyshev–Vandermonde-like matrices over the complex field studied earlier by Kailath and Olshevsky [T. Kailath, V. Olshevsky, Displacement structure approach to Chebyshev–Vandermonde and related matrices, Integral Equations Operator Theory 22 (1995) 65–92], and the classical q-adic Vandermonde-like matrices with respect to power basis by Yang and Hu [Z.H. Yang, Y.J. Hu, Displacement structure and fast inversion formulas for q-adic Vandermonde-like matrices, J. Comput. Appl. Math. 176 (2005) 1–14]. Three kinds of displacement structures and consequently, three kinds of fast inversion formulas are presented for this class of matrices by using displacement structure theory method, which generalize the corresponding results for Chebyshev–Vandermonde-like and q-adic Vandermonde-like matrices.     

FEM Static Analysis of ITER Overall Gravity Support System

For the static structural of ITER overall gravity support are analyzed by the ANSYS software of finite element method （FEM）. All the maximum stress intensity and maximum displacement of overall gravity support system are within the allowable stress limit and displacement limit.     

Effect of source location on particle dispersion in displacement ventilation rooms

A proposed computer model for predicting aerosol particle dispersion in indoor spaces was validated with experimental data found in the literature, and is then used to study the effect of the area and point source locations on particle dispersion in displacement ventilation （DV） rooms. The results show that aerosol source location has a strong impact on the spatial distribution and removal rate of indoor particles. Particle removal performance depends strongly on ventilation efficiency and particle deposition rate on indoor surfaces. Important consideration for both relative ventilation efficiency and deposition rate consists of the position of the aerosol source relative to the main airflow pattern and the occupied zone.     

Cu Nanoparticles on TiN by Electroless Deposition: Surface‐Mediated Diameter Control and Application to Si Nanowires Growth

Cu Nanoparticles on TiN coated silicon substrates were prepared from well‐defined molecular precursors [CuO^t Bu]₄ in non‐aqueous solutions. The formation of nanoparticles takes place via galvanic displacement and allows for the formation of narrowly distributed Cu nanoparticles with controlled size ranging from 8 to 35 nm through the control of the oxidation state of the TiN surface. The activity of these nanoparticles arrays in low temperature Si nanowires growth by the vapor‐solid‐solid mechanism was also investigated and larger Cu nanoparticles were found to yield higher Si nanowires density.     

On the complex variable displacement method in plane isotropic elasticity

A modified formulation of the complex variable displacement method in plane isotropic elasticity is presented. It makes use of two equations deduced from the planar Navier equations in terms of the complex variable, which differs from England’s original formulation based on only one equation. This formulation is more direct and complements the one by England.     

Sub-nanometric precision displacement sensing using low mass and rough surfaces as movable targets

A novel speckle interferometric method has been developed to measure lengths and displacements over a distance of 100 μm with a resolution less than 1 nm using rough surfaces as movable targets instead of using conventional cube corners or mirrors. The speckle method is able to use Michelson and new configurations to combine the two scattered beams or fields from rough movable and stationary reference targets. The targets can be attached and can be produced directly onto movable actuator type of mechanisms. The phase information is extracted from the randomly modulated signals by employing an apertured disc system or an alternative optical fibre arrangement. This method exploits the concept of using narrow angle scatterers for economical use of laser light, enhanced reliability and modulation criteria. A prototype low-mass interferometric displacement sensor has been constructed to provide a compact and a flexible system. Apart from the measurement of changes in displacements in force and pressure measuring devices, it can also be used for the assessment of small range scanning probes, stylus profilers and in medical field the measurement of elastic properties of ear drums, etc. The sub-nanometre resolution and displacement values are repeatable to within ±1 nm can be demonstrated over distances of up to 2 mm by employing appropriate actuators and translation devices. The performance has been confirmed by comparison work against a conventional interferometric transducer.     

HL-1装置等离子体平衡的实验研究

用对称磁探针测量了HL-1装置等离子体环的水平位移和垂直位移,经微机数据处理系统即时给出了位移随时间的变化曲线,并对装置的杂散场情况作了讨论。实验表明,平衡场和杂散垂直场的合成场能保证等离子体平衡在孔栏中心附近的位置。     

平面上含两鞍结点和一鞍点的余维三多角环的三参数开折

本文应用有限光滑正规形理论，研究了平面上含有两个重数为２的鞍结点和一个双曲比率≠１的双曲鞍点的三类余维三多角环的一般三参数开折．证明了这三类多角环至多能分支出三条极限环，给出了分支图．