建议尽快制定各种回弹仪检定规程

一、回弹仪最大的生产国、使用国理应有完善的检定规程 按检测对象不同,回弹仪分为高强回弹仪、混凝土回弹仪、测砖回弹仪、砂浆回弹仪等。20世纪60年代我国开始生产、使用标称能量为2.207J的用于检测混凝土抗压强度的回弹仪,随后又相继开发出了用于检测黏土砖、砌体砂浆抗压强度和高强混凝土抗压强度的专用回弹仪。     

回弹仪率定值校准及故障排除

回弹仪是用于无损检测结构或构件混凝土抗压强度的一种仪器，由于使用频率较高或使用不当及维护、修理的经验和方法欠缺等原因造成混凝土回弹仪的准确度下降。因此有必要将混凝土回弹仪的基本原理、率定方法及经常出现的问题进行分析，以供计量检定人员及从事公路、桥梁、建筑工地质量检测人员参考。     

混凝土回弹仪的维修

混凝土回弹仪由于保管不妥、使用不当、受湿受潮、灰尘侵入、随便拆卸、使用时间长等诸多因素,经常造成准确度下降和使用寿命缩短。笔者在长期的实践中,得到了一些混凝土回弹仪的维护和修理经验,     

混凝土回弹仪的检验

混凝土回弹仪 ,作为检测一般建筑结构或构件普通混凝土抗压强度的一种非破损检测仪器 ,在我国应用已有四十多年的历史。由于回弹仪具有构造简单 ,性能可靠 ,容易校正、维修、保养 ,且检测技术易于掌握 ,操作方法简便 ,对结构和构件无任何损坏等特点 ,在实际检测中得到了广泛应用。回弹仪为建设工程质量监督部门对工程质量的监督、控制及工程事故分析处理提供了准确数据 ,同时施工单位及时使用回弹仪进行自检也可不断督促自身提高施工质量。要保证回弹仪具有稳定可靠的检测性能 ,必须确保回弹仪工作时应有的标准状态。影响回弹仪检测性能的主…     

检定混凝土回弹仪示值误差的测量不确定度评定

文章依据《混凝土回弹仪检定规程》,将混凝土回弹仪置于回弹仪检定器上,测量混凝土回弹仪的率定值,给出率定值检定结果的测量不确定度评定方法和测量不确定度报告。     

混凝土回弹仪检修技术

<正>本文介绍的检修方法主要针对使用最普遍的M225型混凝土回弹仪,同时可供其他型号的回弹仪参考。一、主要技术指标M225型混凝土回弹仪主要技术指标如表1所示。二、故障原因和检修方法1.中心导杆不顺滑中心导杆与弹击锤经过上下频繁滑动产生油腻或干油腻,使回弹仪率定值降低。在这种情况下,应将机芯取出,抽出中心导杆,把油腻擦干净,涂上少许钟表油,同     

回弹仪测量结果不确定度评定中的几个误区

回弹仪是用于检测混凝土、砂浆、砖抗压强度的仪器,是一种现场检测中使用较为广泛的无损检测仪器。本文分析了回弹仪测量结果不确定度评定中广泛存在的几个误区,提供了更为合理的解决方案。     

《混凝土回弹仪》检定规程的修订

JJG817-1993《混凝土回弹仪》检定规程(以下简称"原规程")自颁布实施以来,对使用回弹法检测混凝土质量起到了重要的作用。随着回弹仪技术的发展,新型技术和仪器的使用使得原规程已无法满足实际检定工作的需求,因此,需要对原规程进行修订和完善。2009年,由陕西省建筑科学研究院和中国计量科学研究院会同有关单位开始对原规程进行修订。JJG817-2011《回弹仪》检定规程(以下简称"新规程")     

混凝土回弹仪弹击拉簧检定装置检定混凝土回弹仪弹击拉簧刚度测量不确定度分析

分析了用混凝土回弹仪弹击拉簧检定装置检定混凝土回弹仪弹击拉簧刚度的标准不确定来源,并对引入的每项不确定度分量进行了评定,最后求出合成标准不确定度和扩展不确定度。     

砼回弹仪常见故障分析及维修方法

当混凝土回弹仪（以下简称“砼回弹仪”）因以下两个因素导致整机内部装配关系或性能发生变化时，会影响其正常工作：     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。     

凝固科学技术与材料

从凝固科学与实践发展的角度介绍了当前凝固材料体系的基本框架和凝固科学主要发展阶段的基本理论。作为材料科学与工程的基本组成，凝固科学技术正在现代科学理论的基础上针对传统材料的改性提高和新材料的发展需求，以控形、控构、控性为目标开展优质铸件的定向、晶体生长、快凝、深过冷及各种新型和超常领域凝固过程的研究，并介绍了其中某些方面和展望了可能的发展趋势。     

Heat and Mass Transfer and Modeling and Prediction of Environmental Catastrophes

Basic definitions and concepts of the physicomathematical theory of natural catastrophes are given. Possibilities of mathematical modeling of natural and technogenic catastrophes are discussed in the context of the theory of heat and mass transfer and the mechanics of reacting media. The importance of taking into account conjugate heat and mass exchange in modeling catastrophes is emphasized. A formula for evaluating the probability of a collisional catastrophe is given.     

Multi-ferroic and magnetoelectric materials and interfaces

The existence of multiple ferroic orders in the same material and the coupling between them have been known for decades. However, these phenomena have mostly remained the theoretical domain owing to the fact that in single-phase materials such couplings are rare and weak. This situation has changed dramatically recently for at least two reasons: first, advances in materials fabrication have made it possible to manufacture these materials in structures of lower dimensionality, such as thin films or wires, or in compound structures such as laminates and epitaxial-layered heterostructures. In these designed materials, new degrees of freedom are accessible in which the coupling between ferroic orders can be greatly enhanced. Second, the miniaturization trend in conventional electronics is approaching the limits beyond which the reduction of the electronic element is becoming more and more difficult. One way to continue the current trends in computer power and storage increase, without further size reduction, is to use multi-functional materials that would enable new device capabilities. Here, we review the field of multi-ferroic (MF) and magnetoelectric (ME) materials, putting the emphasis on electronic effects at ME interfaces and MF tunnel junctions.     

CellML and associated tools and techniques

We have, in the last few years, witnessed the development and availability of an ever increasing number of computer models that describe complex biological structures and processes. The multi-scale and multi-physics nature of these models makes their development particularly challenging, not only from a biological or biophysical viewpoint but also from a mathematical and computational perspective. In addition, the issue of sharing and reusing such models has proved to be particularly problematic, with the published models often lacking information that is required to accurately reproduce the published results. The International Union of Physiological Sciences Physiome Project was launched in 1997 with the aim of tackling the aforementioned issues by providing a framework for the modelling of the human body. As part of this initiative, the specifications of the CellML mark-up language were released in 2001. Now, more than 7 years later, the time has come to assess the situation, in particular with regard to the tools and techniques that are now available to the modelling community. Thus, after introducing CellML, we review and discuss existing editors, validators, online repository, code generators and simulation environments, as well as the CellML Application Program Interface. We also address possible future directions including the need for additional mark-up languages.     

Synthesis and luminescent properties of alkali-metal and ammonium fluorosulfatozirconates and fluorosulfatohafnates

We have synthesized a variety of alkali-metal and ammonium fluorosulfatometallates (titanates, zirconates, and hafnates). The alkali fluorosulfatozirconates and fluorosulfatohafnates have been shown to exhibit efficient roentgenoluminescence (RL) in the UV through visible spectral region, with a maximum at 390–440 nm. Their RL spectra depend significantly on their composition (cation, anion, and water content), coordination of KF and K₂SO₄, and relative amounts of fluorine and SO₄ groups. We have examined the effect of heat treatment on the RL of these compounds. The rubidium and cesium fluorosulfatozirconates Rb₃Zr₂F₉SO₄ · 2H₂O, Cs₂ZrF₂(SO₄)₂ · 2H₂O, Cs₈Zr₄F₂(SO₄)₁₁ · 16H₂O, and Cs₂ZrF₄SO₄ offer the most efficient RL.     

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.