力传感器的校准及测量不确定度评定

描述了静重式力标准机、杠杆式力标准机及叠加式力标准机的结构、校准原理,对力传感器校准结果的测量不确定度影响因素、评定过程及方法作了明确分析。     

叠加式力标准机检定幸存者偏差初探

介绍了叠加式力标准机(以下简称叠加机)的原理和特点.结合检测实际,分析和阐述了叠加机检定工况和使用工况.首次提出了检定幸存者偏差的概念,阐述了叠加机检定幸存者偏差的实验方法,并对部分偏差因素进行了对照实验.新概念的提出有助于探索叠加机检定与使用中的盲区,有助于解释部分叠加机应用中发现的现象和问题,对正确检测、生产、使用和评价叠加机具有积极意义.     

EJⅡ-100型杠杆式力标准机控制系统改造设计

为解决EJⅡ-100型杠杆式力标准机操作复杂、自动化程度低、电子元器件故障、维修频繁等问题,在对力标准机机械结构的检查修复的同时对电器电路及控制系统进行整体升级改造,利用当前主流的PLC控制模式代替传统的单片机控制,并对改造后力标准机功能及技术指标进行测试,使力标准机的工作稳定性及自动化控制程度得到提升,经实验证明,改造后的力标准机各项功能及技术指标均符合设计目标及国家检定规程要求。     

一种新型静重、液压和叠加组合式力标准机

目前．国内生产的力标准机基本上都是单功能的,有液压式力标准机、静重式力标准机、叠加式力标准机等。各种力标准机量程、准确度、可操作性、性价比等也各有特点：静重机准确度高,但一般量程小．大量程成本太高：液压机量程大,但操作繁琐：叠加机可以和液压机一样实现大量程．且操作方便．但长期稳定性差。这几种力标准机的使用功能单一且有限．一个计量部门如果需要计量不同类型的传感器可能需要同时买人多台不同类型的力标准机。投人大、功效低,而且这些单一功能的力标准机使用频率不高．很容易被闲置,造成资源浪费。     

基于压电陶瓷1MN叠加式力标准机设计

叠加式力标准机作为力值计量标准器,广泛应用于各行业。叠加式力标准机采用标准传感器与被测传感器比对的方法实现力值的加载控制,通过对力值施加过程及压电陶瓷力发生装置的逆压电效应工作原理分析,结合计算机和微电子控制技术,设计力标准机专用控制软件实现其自动加载控制、数据采集、数据处理、报表输出等功能;并对力标准机进行数据测试及功能测试,测试结果满足国家检定规程要求。     

高准确度大力值比对方法的研究

由中国计量科学研究院主导的大力值（〉1MN）国内比对，为保证我国力值的准确一致和正确传递，促进我国大力值计量水平的提高起到了重要作用。为制定科学、合理的比对方法，本文对力基、标准机特性，环境温度等影响高准确度大力值比对的因素进行了分析和研究。根据试验数据和参加比对的力标准机特性，提出了大力值国内比对的试验方法。     

1000kN力标准机微机控制系统研制成功

简叙了1000kN力标准机微机控制系统的组成、工作原理、主要功能、软件等。     

力标准机发展综述

本文对不同原理力标准机的特点、现状及发展趋势进行了阐述,并对新型的复合式力标准机原理和价值做了介绍。进而结合力值计量的现状,对一些新的力值计量方法和技术的发展前景进行了展望,以期推动力值计量体系的进一步发展。     

力值计量标准现状及研究进展

在对比分析国际上各类力标准机计量性能的基础上,阐述了我国力值计量标准的研究现状及应用关键技术的先进性.提出并研制了基于静重式力标准机"独立加码"的技术与方法,解决了力标准机砝码逆程交换带来的负荷波动性过大的问题,为进一步研究砝码逆程交换产生的"逆负荷现象"提供了一种有效的技术方法.提出并研制了利用机械传动加载方式的叠加式力标准机,力传感器分组并联延伸力值的试验方法,以及力标准机参考标准量值溯源的方法,对研究建立新的大力值计量标准,具有参考和借鉴意义.     

500kN液压式叠加式力标准机的研制

考虑到各种标准机的特点并结合实际工作情况,本项目所研制的叠加式力标准机采用一个比被检定的测力仪准确度高的传感器作为标准,将其与被校准或检定的传感器串联,并以液压方式加载。通过研究分析伺服控制、液压动力系统的转速转矩、液压源的流量等关键参数以及控制软件,实现了0.03级高准确度叠加式力标准机的研制。     

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.     

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.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...