激光干涉水准标尺检定系统测量误差分析

高精度水准测量是地震形变监测等领域的一种重要手段,水准标尺配合水准仪作为水准测量的重要仪器,应按期进行计量检定。为了提高水准标尺计量检定结果的可信度,研发可靠的测量系统,对检定实验过程中的误差进行分析并控制尤为重要。根据国家计量检定规程JJG 8-1991《水准标尺》,介绍一种符合阿贝测量条件的水准标尺激光干涉测量系统,用于检定水准标尺的米间隔真长和分划误差,对水准标尺检定过程中产生的误差逐个分析。分析结果表明,该激光干涉测量系统可以满足国家计量检定规程中对其他检定装置准确度不低于6μm的要求。     

普通水准标尺分米分划误差测得值不确定度评定

普通水准标尺主要应用于水准测量。本文依据JJG 8-1991《水准标尺检定规程》和JJF 1059. 1-2012《测量不确定度评定与表示》,建立相应的测量模型,分析了普通水准标尺分米分划误差测量不确定度的来源,对其测量不确定度进行评定。     

基于正反图案的亚像素条纹边缘检测方法

为了精确确定格雷码条纹边缘,提出了一种基于正反格雷码图案的直线拟合的条纹边缘定位方法．该方法向测量空间投射条纹宽度相等的正、反色格雷码图案,用摄像机拍摄得到经编码图案调制的强度图像,提取两幅强度图像的条纹边缘区域并对其进行直线拟合,求取两条拟合直线的交点,并将其作为边缘点．采用行扫描的方法求取图像中每一行的边缘点,即可得到图像的条纹边缘．文中具体介绍了测量系统组成、测量及定位原理,分析了具体实现过程．实验结果表明,该方法的相对定位误差小于1％．     

激光干涉仪在水准标尺检测中的若干问题研究

激光干涉仪作为主标准器提供标准长度量值,在水准标尺的检测中是主流的常规方法。尤其检测高精度的因瓦条码水准标尺时,激光干涉仪的测长误差及与其他配套设备的组合所带入的综合误差对测量结果产生怎样的影响,文章就应用激光干涉仪检测水准标尺的过程中常见问题进行分析,从检测原理出发,探讨分析整套装置的综合误差。     

基于莫尔条纹的自准直测角技术

针对方位瞄准过程中的强光干扰问题,在结合光电自准直测角和光栅测长原理的基础上,提出了基于莫尔条纹的自准直测角方法.分析了基于莫尔条纹自准直测角原理,即利用自准光栅像和透射光栅重叠产生莫尔条纹,将角量变化转变为线量变化进行测量.根据该原理设计了光学系统,建立了基于莫尔条纹自准直测角的数学模型,给出了理论计算公式,并进行了测量精度分析.理论计算结果显示,在±15′的视场范围内,系统精度达到1″,优于采用狭缝时光电自准直测量的精度.     

视频分划的自动瞄准技术与应用研究

基于光学分划原理提出了视频分划技术,在此基础上提出了新的自动瞄准技术,并详述了视频分划技术中视频竖线、横线和十字线的生成技术,分析讨论了视频分划技术用于自动瞄准的实现原理及瞄准的精度,还将该技术应用于高速、高精度钢卷尺自动瞄准切零位系统中,取得了显著的成效.基于其具有的超越光学分划技术的优越性能,视频分划技术在自动瞄准、自动测量、自动识别及自动存储等多种实际工程应用中都有广阔的应用前景.     

基于阿贝误差补偿光路的水准标尺检定装置及不确定度分析

现行有效的JJG 8——1991《水准标尺》要求以激光波长作为长度基准,使用激光干涉检定器对因瓦水准标尺进行检定。检定3 m长的水准标尺,若照准部不动而标尺移动,需要6 m长的导轨。为缩短导轨长度,降低加工难度,采用标尺固定而照准部移动的检定装置,可有效地将导轨长度由6 m缩短至3 m。由于不满足阿贝原则,检定装置设计基于阿贝误差补偿光路的结构,实现对阿贝误差的消减。该装置补偿性能的实测结果表明:利用光学补偿的方法极大地消减阿贝误差。"米间隔长度平均值"不确定度的评定结果表明:该装置可以满足水准标尺检定规程中对检定装置的相关要求。该补偿光路也可用于其他长度测量系统。     

二维自跟踪视觉准直测量系统

为了提高自准直仪的测量精度和降低人眼瞄准的劳动强度和主观误差,提出一种基于机器视觉的二维自跟踪视觉准直测量系统。该系统由光学准直仪、CCD和图像采集卡等组成。以面阵CCD代替人眼对自准直仪的十字分划板图像进行瞄准;采用图像不变矩自动搜索算法和hough变换、亚像素细分等方法实现对小角度的自动精确测量。实验结果表明,该系统测量范围达到±15',最小分辨力优于0.1″,与MJS双频激光测角系统比对误差在0.6″以内,测量精度高于MJS,而且操作方便,易于推广。     

含孤立物体场景的高速、高密度三维面形采集

提出了一种用于采集含空间孤立物体场景的高速、高密度三维面形采集方法。该方法将三幅图案高速投影到被测物体上并同步采集图像,从而实现场景三维形貌及纹理的高速记录。其中两幅图案是互相具有π相移的正弦条纹,采用傅里叶变换法求解变形条纹相位。将拍摄到的两幅变形条纹图相加可得到物体表面纹理。另一幅图案用来确定条纹级次,实现绝对相位测量,解决高速形貌采集中孤立物体相位展开难题。它由一系列宽度与正弦条纹周期相同的竖条构成,采用三种灰度对竖条编码。每个竖条由单一灰度或两种在竖直方向上周期性分布的灰度构成,这样可编6个码。将竖条按由这些码构成的伪随机序列排列,得到编码图案。测量时,对拍摄的编码图案解码,通过子序列匹配来确定对应正弦条纹的级次。设计了采用DLP投影仪及高速摄像机的高速测量系统。采用提出的方法实现了640×480分辨率下每秒60帧和320×240分辨率下每秒120帧的三维形貌及纹理采集。     

提高显微硬度测量精度的途径

撰写本文的目的在于提高测量者的测量素质。一、瞄准精度瞄准精度是指测量者通过肉眼视觉使测微计活动分划板的刻线与正方形压痕对准的程度。据分划板刻线形式的不同,对压痕瞄准的部位不同,图1为常见分划板刻线形式。按分划板刻线形式,瞄准方式有两种: 1.尖端瞄准式[如图1(a)、(b)、(c)、(d)所示]:刻线对压痕的尖端瞄准。 2.棱边瞄准式[见图1(e)、(f)、     

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.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

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.     

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.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

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.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.