An iodized mounting medium for coal particles

A high electron-density embedding medium was developed for SEM observation of inorganic constituents of organic or carbonaceous particles. The components used are a common epoxy resin in which iodoform is dissolved before the addition of the hardener. An iodoform content of 10% by weight proved satisfactory for obtaining excellent contrast between the matrix and embedded carbonaceous particles in the SEM. The system has been successfully applied in the preparation of polished specimens of coal particles. There is no interference between the iodine and any of the most abundant or most important coal mineral components, but it was found that the epoxy resin contained chlorine as a contaminant.     

动力总成悬置系统动态特性仿真分析

动力总成悬置系统是汽车振动系统的一个重要子系统,对改善汽车平顺性和舒适性有很大的影响。应用拉格朗日法建立了六自由度动力总成悬置系统的数学模型,并用Newmark法和Simulink仿真模型两种方法对动力总成悬置系统怠速工况进行了仿真分析,两种方法的仿真结果相近,说明模型的正确性,在此基础上对动力总成悬置系统在怠速工况下进行了动特性分析,最后将仿真动特性结果和实测进行了对比,仿真结果和实验结果基本一致,说明其具有工程应用价值。     

楔块调整式Talbot干涉仪的光学设计

为改变光纤光栅的写入Bragg波长,研制了包括一块相位模板和两块紫外反射平面镜的楔块调整式Talbot干涉仪。在写入光纤Bragg光栅的过程中,通过调整两平面镜的反射角度可改变由±1级衍射光束经两平面镜反射后形成的干涉条纹的周期。最后,放置在可调谐干涉区的光纤就可刻写成具有不同写入Bragg波长的光纤光栅。值得注意的是通过选择不同倾斜角α的楔形块,决定了光纤光栅的写入Bragg波长的改变率和干涉条纹棱脊位置的位移率。     

水平式经纬仪指向误差的统一补偿技术

为修正水平式经纬仪的指向误差,提出了一种针对视轴指向的统一补偿模型.根据水平式经纬仪的光机结构,建立了照准坐标系和地平坐标系;通过两坐标系的几何关系得到目标在地平坐标系下的坐标方程,并对该方程进行全微分,得到地平坐标误差与指向误差的关系式.针对设备主要误差源之一(3轴误差)进行5次线性变换,推导出目标在地平坐标系中关于...     

斜轴式天文望远镜机架的驱动控制

针对斜轴式天文望远镜传统机架中的非垂直轴系结构会导致像场旋转,从而影响天文望远镜指向和跟踪控制的问题,研发了新的45°斜轴式天文望远镜机架。设计时,选取太阳为跟踪目标来搭建硬件机架驱动控制系统;利用图像传感器实时捕获目标,经数字信号处理(DSP)芯片精确解析目标质心,通过图像消旋解耦出方位与斜轴两方向的偏差。然后,结合模糊控制与神经网络的各自特点,设计了单神经元模糊自适应PID控制算法实施偏差调节,以实现对目标的定位与跟踪。实验结果显示,该驱动控制系统的水平与斜轴方位的跟踪偏移误差均在±2pixel以内,水平指向偏移误差均值为0.123 2°,俯仰指向偏移误差均值为0.155 3°。得到的结果表明该驱动系统鲁棒性强,能够克服斜轴机架像场旋转导致的控制问题且满足精度要求。     

Polyester resin as a mounting medium for light microscopy

The use of a commercially available polyester resin is described for the production of whole-mount preparations and as a mounting medium for histological sections. Any standard technique can be used which involves xylene as the clearing agent. It is considered that the slides produced are much stronger than those made with traditional mounting media and do not require long drying times before use. The method is particularly suitable for mounting thick specimens for teaching purposes.     

Geometric error calibration of multi-axis machines using an auto-alignment laser interferometer

This work will report the development and application of an auto-alignment laser interferometer system for the geometric error calibration of CNC multi-axis machines. The system is capable of a diagonal displacement measurement, where multiple machine axes are moved simultaneously, with automatic optic alignment. This capability provides a solution for quick evaluation of the overall volumetric error of a multi-axis machine tool. One application of the system is that the 21 geometric errors of a 3-axis machine can be quickly estimated from the displacement measurements of some determined diagonal lines in the working volume. Compared with a time of several days using a conventional laser interferometer system, it takes only 1 hour for the proposed system to complete the geometry calibration of a 3-axis machine. A method for the roll calibration of a vertical axis is also proposed and demonstrated in this work.     

BARCOS, an automation and remote control system for atmospheric observations with a Bruker interferometer

In order to make long-term monitoring of the atmospheric composition using commercial Bruker Fourier transform spectrometers more cost effective, a system called BARCOS has been developed. The system enables one to perform the operation of the spectrometric atmospheric observations in a remotely controlled or autonomous way, without human presence at the measuring site. Several observation geometries are foreseen, including solar and lunar absorption spectrometry. BARCOS is built using existing commercial hardware and software components, including the Bruker software for the operation of the spectrometer (OPUS) and runs in a personal computer (Microsoft) environment. It includes a small meteorological station. It is a flexible system, allowing manual interventions at any time. To run BARCOS effectively, the only prerequisite is that internet access is available at the site of operation. This article describes the BARCOS system hardware and software configurations.     

Polarized light interferometer for laser fusion studies

A polarized light interferometer, suitable for the high-speed photography of microscopic objects in laser fusion experiments, is described. Based on a Wollaston prism as beam splitter, its main advantages are its relative simplicity, the absence of alignment and stability problems, and the extended spectral range down to 0.18 mum wavelength. The interferometer has been successfully applied in CO(2) and neodymium laser plasma interaction studies with laser illumination at 0.694 mum (ruby laser) and 0.265 mum (4th harmonic of the Nd(3+) laser) wavelength.     

Volumetric phase-measuring interferometer for three-dimensional coordinate metrology

We present a volumetric interferometer that has been specially designed to improve the measurement accuracy of the three-dimensional coordinate metrology by reducing excessive Abbe offsets. The interferometer is composed of two main parts; one is a three-dimensionally movable target and the other is a stationary two-dimensional array of photo-detectors. The target made of point diffraction sources emanates two spherical wavefronts, of which interference intensity is monitored by the photo-detectors. Applying phase shifting allows the phases of the photo-detectors to be precisely obtained, and the measured phases are fitted to a geometric model of multilateration so as to determine the xyz-location of the target by minimizing least square errors. A prototype built on a CMM demonstrates that the proposed interferometer is capable of measuring the xyz-coordinates of the probe with a volumetric uncertainty of less than 1.0 μm.     

线性位移台直线度高精密外差干涉测量装置

直线度测量中往往存在有限的测量范围、精度低和阿贝误差等问题。本文提出了一种高精密直线度外差干涉测量装置,该装置由Koester棱镜、角锥棱镜、1/4波片、楔面棱镜和楔面反射镜构成。楔面棱镜为直线度传感元件,角隅棱镜和楔面反射镜是测量信号的回光元件。双频激光信号进入直线度干涉仪后组成几何空间对称四光路测量信号。四路测量光走过几乎完全相同的路径有效地提高了干涉仪的稳定性,并且使空程误差最小化。使用楔角为1°的楔角棱镜和2π/512细分的相位计,直线度测量分辨力为17.71nm。该方法不需要与行程同长的大反射参考镜,但同样能实现高分辨率,理论和实验证明空间对称测量结构避免了由俯仰,偏转和滚转角引起的阿贝误差的串扰,而且光学元件少,结构简单,方便易用,结果可以直接溯源到米的定义。     

Novel interferometer for the measurement of plasma density

This report describes an interferometer recently developed and tested in prototype form. The device combines certain features of predecessor interometers but in a module which, subject to limitations on path-length and bandwidth, is simpler to use.     

Calibration of linear encoders with sub-nanometer uncertainty using an optical-zooming laser interferometer

The nonlinear errors of high-precision linear encoders were calibrated by using a nanometer-length calibrator that was based on the optical-zooming laser interferometer with an optical frequency comb. A transmission-type linear encoder and a reflection-type linear encoder were calibrated, and the cyclic nonlinear errors were evident. The magnitudes of the observed cyclic errors were 0.1 nm and 0.2 nm, respectively, and the best calibration uncertainties were 0.55 nm (k = 2). A traceable calibration service for linear encoders with the best calibration uncertainty in the sub-nanometer range has started based on this work.     

大口径反射镜水银带支撑结构物理参数分析

针对大口径反射镜在竖直状态下工作的情况,用有限元方法对水银带支撑结构的物理参数如带宽、支撑位置在理论上予以分析.在具体的优化计算过程中,以镜面RMS值为目标函数,考查、修改支撑结构的带宽、位置,最终确定了可获得理想面形的水银带支撑结构.分析结果表明将该水银带支撑方案应用于大口径反射镜具有可行性,并为水银带支撑结构物理参数的确定提供了数值依据.     

A new specimen mounting system for scanning electron microscopy*

A system of specimen mounting discs and holders has been developed for use in high vacuum. Discs are held in place with a tightly fitting cap, thus avoiding the use of adhesives. The mounting discs are especially convenient for biological preparations, are much less expensive than conventional SEM ‘stubs’ and are easier to handle and store.     

Diffraction interferometer for studying refractive index dynamics

An experimental assembly is created and a method for simultaneous studying dynamics of phototransformation of holographic photopolymer materials by spectrophotometric and interferometric methods is elaborated. A special diffraction interferometer with combined branches is developed. The interferometer ensures the sensitivity to the change in the refractive index Δn ～ 10^?3 for ～100 μm specimens.     

A microwave two-wave interferometer for plasma diagnostics

The scheme and the main elements of an interferometer simultaneously operating at frequencies of the 8-and 4-mm ranges are presented. To combin e two radiations in a common waveguide section and separate them by sending to the corresponding receivers, a special separation filter has been developed. A homo-dyne technique for transferring phase measurements to an intermediate frequency is employed in the interferometer. The range of unambiguously measured phase shifts is 1.5°—360°, and the phase-shift measurement error is within 5%.