星体标定技术在光电跟踪系统计量确认中的应用

测角精度是光电跟踪系统计量确认中最重要的技术指标，通常是以校准塔和方位标为基准进行单项误差标定的，其过程繁琐、周期长。为了提高测量及校准精度，缩短确认周期，本文在实践的基础上，研究了一种应用星体标定技术开展光电跟踪系统计量确认的原理、方法、程序；讨论分析了误差来源、数学模型的建立及其解算方法。     

分布动载荷频域识别的试验动标定方法研究

分布动载荷识别是工程中最为复杂也亟需解决的结构动力学逆问题，通常可以转化为正交多项式系数的识别，从而衍生出了动标定技术。传统的仿真动标定方法是基于有限元仿真模型来实现的，然而仿真动标定方法存在模型误差，导致载荷识别精度不高。因此本文基于 Legendre 正交多项式和 Gauss?Legendre 积分提出了分布动载荷频域识别的试验动标定方法。该方法的关键是通过测量有限的高斯点和响应点间的频响函数来完成分布载荷识别过程中的动标定，克服了传统标定在试验时无法加载正交多项式载荷计算标定矩阵的局限性，同时避免了模型误差对标定矩阵精度的影响，大大提高了载荷识别的精度。为了验证该方法的有效性和精度，将本文所提出的试验动标定方法与现阶段已有的仿真动标定进行了对比分析，并讨论了不同高斯点数对识别精度的影响及抗噪性能；此外，还通过相应的试验进一步验证了该方法的可行性与工程适用性。     

同步微离轴数字全息显微系统的空间失配标定方法

现有的空间失配标定方法受原理限制只能实现像素级的标定精度,且易受环境噪声干扰。本文提出了一种亚像素级的同步微离轴数字全息显微系统的空间失配标定方法。该方法在建模时不仅分析了图像分割导致的横向位置误差,还进一步考虑了传感器倾斜引入的纵向位置误差,并将标定过程归纳为求解非线性多变量优化问题。在本文中,粒子群优化算法因其结构简单、收敛效率高、全局搜索能力强等优势,被用于解决这一优化问题。在标定过程中,建立了基于相位畸变的纯相位波面,并将纯相位波前的均方根误差作为目标函数,以去除噪声对标定精度的影响。仿真结果证明本文方法具有亚像素级精度,实验证明了其在实际系统中的有效性。     

可变长度光电基准尺设计技术（英文）

根据激光经纬仪的特点,提出了一种以高精度光电位置敏感器(PSD)为核心器件,用于激光经纬仪测量系统快速、准确定向的可变长度光电基准尺.介绍了基于此基准尺的激光经纬仪测量系统定向方案以及基准尺整体设计方案,给出了该基准尺的结构、标定以及解算方法.最后,通过两台莱卡激光经纬仪组成的双站测量系统评价该可变长度基准尺的精度.经实验验证,利用该可变长度光电基准尺定向后,双站经纬仪的相对测量精度为0.04%.     

一种显微图像测量系统的标定方法

提出了一种显微图像测量系统的标定方法。该方法通过同一对平行边缘在垂直和水平方向的两幅图像,计算水平比例因子;利用标定物直线边缘的图像,并运用优化的方法来计算成像系统的畸变系数和主点位置。在上述计算的基础上,利用量块来标定系统的放大倍数。标定过程所需的标定物为量规和带有平行刻线光学器件,如分辨率板等,因此方便实用。试验结果表明,该方法标定精度较高,标定后的实验装置的极限误差3σ为2.26μm。     

基于ADIS16488 MEMS IMU标定测试方法研究

MEMS惯性器件误差是导航系统主要的误差源,而确定性误差和随机误差是惯性器件主要误差,确定性误差可以通过标定补偿.本文通过分析MEMS IMU标定误差模型,设计了加速度计的6位置标定法和陀螺仪的速率快速标定法,推导了适用最小二乘的标定参数辨识方程.以ADIS16488 MEMS IMU为标定测试对象,利用高精度3轴转台进行了标定试验,标定误差补偿后MEMS IMU器件精度等级提高了至少1个数量级,证明该方法有效.     

提高光电成像挠度系统的识别精度

光电成像挠度系统在桥梁结构状态健康监测系统工程实践中由于受到雾、强光等天气因素干扰会影响识别精度。针对该问题,本文在分析了光电成像挠度测量系统组成和成像识别原理基础上,深入研究了各种不利的天气因素干扰对挠度测量系统成像识别精度的影响,并在图像增强基础上提出一种投影差分算法来提高在不利天气条件下光电成像识别精度,该算法通过对比实验(雾天:该方法的均方差为1.632 231,传统方法均方误差为16.534 08;强光:该方法的均方差为2.182 247,传统方法均方误差为23.018 13)验证了该方法在不利天气条件下相比传统方法将识别精度从厘米级提高到毫米级,大大增强了光电成像挠度系统的可靠性,并在重庆马桑溪长江大桥、重庆高家花园嘉陵江大桥等桥梁结构状态监测系统的光电成像挠度测量系统工程实践中得以成功检验。     

惯性导航系统中加速度计标定方案设计与研究

本文主要基于车载筒装导弹基础之上,对捷联惯性导航系统的加速度计标定方法和误差机理进行了研究。首先,对惯性导航系统加速度计误差机理进行分析,提出了加速度计的标定补偿方案,以车载作为激励方式,设计了不开箱加速度计标定方法,该方法能够对误差进行补偿来提高关系导航系统的精度。     

一种三轴光电跟踪系统指向误差修正的方法

为了提高三轴光电跟踪系统的指向精度,针对三轴光电跟踪系统的光机结构提出了一种具有明确物理意义的指向误差修正模型。首先,根据四元数的旋转变化方法详细分析了各轴系误差对空间目标指向误差的映射关系表达式,然后,通过这些关系式建立三轴光电跟踪系统的指向误差修正模型。实验结果表明,该方法可以将有效的修正系统指向误差,且外符合修正精度高于球谐函数指向误差修正模型,同时该方法在装配调试阶段对预估指向精度具有一定的参考指导作用。     

六维力传感器静态标定系统误差分析

介绍了六维力传感器静态标定系统的构成,分析了标定系统的误差来源,建立了综合误差模型,并针对该误差模型提出了减小误差、提高测量精度的措施。分析结果表明,该静态标定系统的MZ通道的满量程误差为2.48%,其余通道均在2%以下。加载力的方向偏差是六维力传感器标定系统误差的主要来源,标定时应该使用高精度的方向校准设备,减小力的加载误差。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.