水准仪检定装置水平准线偏差检定方法的探讨

根据水准仪检定装置的工作原理,建立了水准仪检定装置水平准线偏差检定方法的数学模型,并以三点互调式水准仪检定装置为研究对象进行了不同检定方法的比对实验,发现了不同检定方法的检定结果存在较大差异.通过分析检定方法的数学模型,提出了引起水平准线偏差测量结果不确定度的因素,指出检定结果差异的原因,证明了水平准线标准装置检定法是检定水准仪检定装置水平准线偏差的最佳方案.     

基于“专用光管法”的数字水准仪检定装置研制

数字水准仪被广泛应用于高程测量,须经检定确保其量值准确可靠满足规程要求后才可用于测量。现行有效的JJG 425——2003《水准仪检定规程》中提出"专用光管法"和传统的"室外法"两种检定方法,但没有对"专用光管法"所需检定装置的结构和参数提出具体要求,无法参照该规程建立检定装置。该文研制一套基于"专用光管法"的室内检定装置,采用两支对径放置的、内置条码分划板的内调焦平行光管,实现数字水准仪的室内检定。实测结果表明:该装置满足JJG 960——2012《水准仪检定装置检定规程》的要求,可用于数字水准仪的检定,并对"专用光管法"检定装置的研制有一定的参考价值。     

光学水准仪计量检定技术研究

本文是阐述研究测绘技术中最常用仪器一光学水准仪的计量检定技术中的量值溯源检定装置、检定方法和检定结果的处理。     

光学水准仪计量检定技术研究

本文是阐述研究测绘技术最常用仪器一光学水准仪的计量检定技术中的量值溯源检定装置，检定方法和检定结果的处理。     

水准仪磁致误差检定装置研究

水准仪在进行精密水准测量时,测量数据会因受到地球磁场的影响而产生偏差,因此,在水准仪的检定项目中,磁致误差是具有重要意义的一项。文章针对现行的水准仪磁致误差检定规程,围绕对检定装置的要求和全方位最大磁差方位角的检定方法进行论述,以帮助相关检定人员更好地理解规程。同时介绍了一种基于Lab VIEW的可编程电源控制系统,使检定程序更加智能化。     

水准仪检定装置"水平准线偏差"的测量不确定度分析

1　引言水准仪检定装置是检定水准仪的水平标准器。它建立了一条成像在无穷远的水平方向的视准线 (简称为水平准线 )。水准仪检定装置的“水平准线偏差”是装置的主要技术指标。本文以地震研究所的ＪＳＪ型经纬仪水准仪综合检验仪 (以下简称为ＪＳＪ仪器 )为例 ,对其“水平准线偏差”的各构成因素作了分析 ,并依据ＪＪＦ1 0 5 9-1 999《测量不确定度评定与表示》 ,给出ＪＳＪ仪器“水平准线偏差”测量不确定度的评定与表示。2　测量方法参照国家计量校准规范《水准仪检定装置》(报审稿 ) ,水准仪检定装置的“水平准线偏差”是用 0 2″陪检…     

经纬仪水准仪检定装置不确定度评定

本文详细介绍了经纬仪水准仪检定装置的测量不确定度评定的具体方法.     

水准仪检定装置的校准

一、概述提供误差不大于±2〃的水平视准线是水准仪检定装置的最主要性能指标。基于自动安平原理的“JSJ精密水准仪检验仪”(以下简称JSJ检验仪)准确度高、功能全,已在计量、测绘、科研、生产等各行业广泛使用。由JSJ检验仪的光学原理图(如图1所示)可以看出,由于该仪器具有光楔测微器、自平准线微校光楔、测微目镜等观察、测量、校准装置,可以方便地根据JJG960-2001《水准仪检定装置》检定规程的要求,利用水平陪检标准器进行周期检定。本文介绍了两种实用的校准方法,其扩展不确定度不大于0郾5″,便于现场应用。二、水平陪检标准器水平…     

水准仪在钟罩式气体流量标准装置检定中的应用

详细介绍了水准仪在钟罩式气体流量标准装置检定中的应用,特别是在钟罩式气体流量标准装置没有挡板和光电发讯器的情况下,这种方法不但提高检定效率,更主要是提高检定的准确度,大大消除了人工标记所带来的误差。     

数字水准仪室内外检定方法的分析与比较

正一、室内外方法的比较及数据分析1.差异性比较选用相同的被测对象与不同的测量方法,来评估分析光管模拟外业与实际室外法的检定结果的差异性。选用5台被检数字水准仪DiNi03,针对我院数字水准仪检定装置进行室内法检测。检定之前,需将被检的数字水准仪光学i角调校准确,或与基准水平线符合,以保证其光学i角相同,从而保证光     

热交换器的分类及优缺点分析

热交换器是将不同温度介质之间的热量通过热传导的形式,由高温介质传递给低温介质,使介质达到生产所需温度的工艺设备,也可作为一种节能设备使用.通过对不同热交换器的结构分析,总结不同热交换器的优缺点、适用环境,为生产工艺设计人员及设备制造单位在选择可降低能耗、提高效率的设备上提供参考.     

聚苯胺及其复合物的制备和结构及形貌分析

通过化学氧化法分别制备盐酸,盐酸和十二烷基苯磺酸,碳纳米管(MWNTs-COOH)掺杂的聚苯胺,利用红外光谱,紫外光谱,扫描电子显微镜和透射电子显微镜对所制备聚苯胺的结构和形貌进行分析。分析不同掺杂物对聚苯胺的结构和形貌的影响;同时研究了超声波作用对聚苯胺形貌以及聚苯胺包裹MWNTs-COOH情况的影响。     

Thermodynamic similarity and prediction of the properties and characteristics of substances and processes

Principles of the theory of thermodynamic similarity are considered in application to all aggregate states of a substance, including phase transitions, and to the change in dissipative structures in open systems.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 5, pp. 709–716, November, 1987.     

Modelling and computation of curing and damage of thermosets

The curing of thermosets is a complex process involving the transition from a fluid into a (visco-) elastic solid. This phase transition comes along with an increase in stiffness and a volume shrinkage of the polymer. The latter may lead to severe residual strains and stresses, which in turn can cause damage in the final, usually quasi-brittle material. In this contribution a constitutive model is developed which takes into account the curing of a thermosetting material together with the process-induced damage as resulting from curing shrinkage. The curing of the material is governed by a phenomenological hypoelastic constitutive equation which includes temporal evolutions for stiffness and volume shrinkage. Thermal and viscous effects are neglected in the present study. An isotropic gradient-enhanced damage model is adapted to describe the damage evolution. The curing-damage model is implemented into a finite element code and numerical examples for thermosetting materials demonstrate that the proposed model is capable to predict cure-induced damage in thermosets.     

碳化硼陶瓷增韧补强和致密化研究现状及其展望

碳化硼陶瓷具有极高的硬度,然而其低韧性、低抗弯强度、难以致密化限制了它的广泛应用.已有一些研究集中于碳化硼陶瓷增韧补强和致密化,对这一方面国内外研究进展进行了归纳与评述,阐明各种增韧补强和致密化方法的优缺点,提出碳化硼陶瓷增韧补强和致密化研究值得发展的一些方向.     

Measurement and analysis of elastic and anelastic properties of alumina and silicon carbide

Measurements of dynamic Young's modulus, E, and damping as a function of temperature, T, were made for alumina and silicon carbide. The Young's modulus data were compared with some from the literature, and analysed in terms of a theoretical framework relating the Debye temperature, θD, with the elastic constants. For both materials this analysis yielded a ratio T₀/θ_D which was near 0.4, where T₀ is an empirical fitting constant for the plot of (E(0)−E)/T versus 1/T (E(0) is the value of E at 0 K). The analysis of the damping data in terms of an Arrhenius type dependence led to effective activation energies near kT, where k is Boltzmann's constant. This revised version was published online in November 2006 with corrections to the Cover Date.     

Mechanisms of Corosion and Oxidation of Metals and Alloys

Selected topics in field of the study of the mechanisms of corrosion and of oxidation of metals or alloys are presented. The first part reports a new model for the mechanism of the breakaway oxidation of ferritic stainless steels in water vapour. The second part is devoted to the physico‐chemical aspects of oxidation and presents experimental methods useful in the kinetic modelling applied to two alloys, the zircalloy‐4 and an AlMg5 % in the liquid state. In the third part the physical and numerical modelling of the stress corrosion cracking behaviour in face‐centered cubic (fcc) alloys is detailed, which enables the study of the influence of macroscopic parameters (such as the temperature or hydrogen activity) on the fracture process.     

Surface-charge density and potential of coal-liquid mixtures and control of their stability and fluidity

The preparation conditions of concentrated (>70%) aqueous suspensions of coal were optimized, as were the surface charge density and the surface potential of the coal-water suspensions. The theoretical study showed that (1–3) or (2–3) electrolytes such as Na₂SO₄ or Na₅P₃O₁₀, greatly increase the surface charge density and the surface potential of the coal particles in water. This study has led to the interesting result that thinners and stabilizing agents of concentrated clay suspensions, such as lignosulphonates, tripolyphosphates, polynaphtalene sulphonates, etc., must also be good thinners and stabilizing agents for ground coal-water suspensions. Two parameters were controlled: the stability and the fluidity of the suspensions. A penetrometry technique revealed the importance of the resistance coefficient,C _r that can be used as a criterion for the evaluation of coal-water mixture stability and fluidity. Concentrated coal suspensions (about 75% of solid by weight) were prepared in water by using different additives, for instance sodium tripolyphosphate (NaTPP) and surfactants like lignosulphonates (by coupling of the dispersion and stabilizing effects) with the optimum concentration ratio of these two products equal to 1.9. The stability of the suspensions was then greater than 2 months and the viscosity was 1900 cP.     

SARS传染病数学建模及预测预防控制机理研究

首先，利用疾病传播的一般规律及人口守恒统计法则建立了四类人的SARS传染病数学模型，然后运用数学方法对四类人的SARS传染病数学模型进行分析，得出了其生理意义和预防、控制机理。其次，利用人工神经网络理论建立了SARS的预测模型，以北京市的SARS数据为例进行了预测和分析，预测结果显示该模型简单易行，预测精度高。