检测设备偏离校准状态的纠正和预防

在质量体系认证或完善计量检测体系确认工作中，对发现检测设备偏离校准状态时，要求供方采取一定的纠正和预防措施。这项工作在实际操作中，大家普遍感到有一定的难度，也是目前计量工作的难点。现提出一些方法，与大家商讨。l检测设备偏离校准状态的发现检测设备出现偏离校准状态，一是在检测设备使用过程中，另一种是在检测设备的周期校准过程中。第一种情况有：使用者在使用检测设备检测产品及其零件过程中，在使用一段时间后（未到重新校准时间）发现检测设备性能（示值）发生变化，怀疑检测设备偏离校准状态，如原先检测结果与现在检…     

泄漏电流测量仪校准方法的研究

本文介绍了泄漏电流测量仪的分类和校准方法,重点介绍了校准不同类型泄漏电流测量仪时对计量标准的要求。     

地方动态

正京津冀三地政府计量行政部门发布五项共建计量技术规范3月29日,京津冀三地市场监管局共同发布《数字温湿度计校准规范》等五项共建计量技术规范。这些规范已于4月29日正式实施。《数字温湿度计校准规范》为京津冀地区粮食储备、医药卫生、检测实验室等行业领域广泛使用的温湿度计提供了检测依据。《钳形泄漏电流表检定规程》、《耐电压测试仪检验仪校准规范》为京津冀地区电器安全领域使用的计量器具提供了检测保障。《水泥净浆搅拌     

食品的金属检测

现在，金属检测机作为常规检测设备。在食品加工领域已得到广泛应用。许多食品公司也购买了金属检测机，并制定了金属检测规范，以及检测机灵敏度的检查标准。然而，这些检测机只有在规范的检测程序条件下，才能保证生产线生产出无金属杂质的产品。     

平面波耦合腔中热传导和声泄漏对低频互易校准的影响

针对低频耦合腔互易校准中存在的热传导和声泄漏问题,通过理论计算和不同长度耦合腔的系列实验研究,探讨其对互易校准结果的影响规律。首先阐述了互易校准原理及电容传声器低频时的频响特征,传声器均压孔在声场外时,低频声压灵敏度随着频率降低而逐渐增加;其次,对发射传声器-耦合腔-接收传声器构成的耦合腔系统中的热传导修正因子进行计算,结果表明,随着耦合腔长度变长,热传导修正因子变小,不确定度分量变小;通过不同长度的耦合腔组成的互易校准系统研究声泄漏的影响并探讨其优化方案,实验结果表明,10 mm和15 mm耦合腔对互易校准结果影响较小,重复性高,该实验结果与传声器的低频响应特性一致。     

浅谈温湿度与燃气检测机的设计

为了使城市居民在使用高效、清洁的燃气能源的同时得到更好的安全保障,本文设计开发了适合家庭使用的燃气检测机。采用了具有强大编程能力的STC12C5A60S2单片机为燃气检测机的核心部件,对家庭使用的可燃气体检测、报警等控制,本文介绍了一种居民用燃气检测机的设计开发,讨论了燃气检测机的结构组成、工作原理、硬件设计和软件设计等。该系统具有结构简单、经济实用和智能化程度高等特点。     

泄漏电流测量仪校准方法的研究

泄漏电流是一项重要的安全性能指标.家用和类似用途的电器、医疗设备、电子测量仪器等都对泄漏电流的测量提出了较高的要求.目前,国内外生产厂家生产的泄漏电流测量仪种类较多、性能指标各异、测量原理多样,虽然JJG843-2007<泄漏电流测量仪>检定规程规定了几种检定,校准方法,但针对不同测量原理的泄漏电流测量仪利用何种方法校准才能得到满意的校准结果,值得认真研究.     

血细胞分析仪计量检定误差分析及规程修订建议

一、血细胞分析仪检测概述 目前，国内使用的血液分析仪基本上是进口产品。国内行业检测的现状是，由于各厂家生产的血细胞分析仪采用的检测原理和试剂的性质不同，造成结果的潜在差异，尤其对于一些特殊标本，在不同的检测系统中得到的数值有时会与真正的数值出现差异。目前，我国医疗系统常以室间质评和室内质控结果作为判断仪器准确性和一致性的依据。即指使用配套试剂，用配套校准物定期进行仪器校准。     

阀门内漏检测方法研究

火电机组汽水系统的主要阀门泄漏时，产生汽水损失，浪费资源，降低机组的经济性，阀门由于长期泄漏引发爆管，给设备的现成工作人员带来危害。因此，及时发现阀门泄漏，对组经济安全运行非常重要。本文分析了目前的主要检测方法，并对基于传热学的检测方法进行了理论分析，可实现在线阀门泄漏量的定量计算、判断阀门泄漏状态。     

浅析可燃气体检测报警器的原理及校准

目前,可燃气体检测报警器已被广泛应用于石油、燃气、化工、油库等存在有害气体的各个行业,用以检测室内外危险场所有害气体的泄漏情况。所以,可燃气体检测报警器的准确与否,尤为重要。本文着重分析了可燃气体检测报警器的内部结构及工作原理,并进一步阐述了如何对可燃气体检测报警器进行校准以及校准时的一些注意事项。     

漏电保护器测试仪的几种校准方法

文章介绍了漏电保护器的工作原理,对漏电保护器测试仪动作电、流跳闸时间和回路阻抗等主要参数,分析几种校准方法,并对各种方法的优缺点作了评价,同时还简单地介绍了各测试参数的不确定度的来源和评定结果。     

氧化锌避雷器测试仪阻容网络校准方法

对氧化锌避雷器测试仪的传统阻容网络校准方法进行分析,指出电阻的时间常数、电容的损耗因数对泄漏电流的校准有一定影响。提出了基于相位差测量的数字化校准方法,采用数字采样方法对关键参数相位差进行测量,通过实验验证,证实了该方法具有较高的准确度,可用于氧化锌避雷器测试仪的校准。     

ZrO_2-SiO_2复合物作为MgO粉高温添加剂的电学性能研究

采用溶胶-凝胶法合成了ZrO2-SiO2复合物,通过电参数测试仪、泄漏电流测试仪测量了加入ZrO2-SiO2复合物后的电工级MgO粉的电学参数和泄漏电流,分析了ZrO2-SiO2复合物用量、ZrO2和SiO2质量配比以及退火工艺对其电学性能的影响。研究表明,将ZrO2和SiO2质量配比为4∶6,用量为2%的ZrO2-SiO2复合物装入电热管中,经退火工艺处理后管子的泄漏电流最小,较适合作为电工级MgO粉的高温添加剂。     

Leakage analysis of packages by the electrolytic test

The microhole tester is a new laboratory instrument for detection of leakage in packages. The instrument is based on electrolytic conductance measurement using direct current and it quantifies the summarized hole size in a package. In this study the reliability and validity of the microhole tester have been evaluated by testing different kinds of aseptic, retorted and gas flushed packages containing both solid and viscous products. In the case of gas flushed packages filled with a solid food product the instrument detected 100% of the leaking packages with artificially made microholes with diameters of 7–356 μm after emptying the packages of food. Retorting tended to block the holes with food and lowered the sensitivity. In the case of retorted packages with viscous food the microhole tester reliably detected hole sizes larger than 25 μm. Adding a surface active agent, poly(ethylene oxide) (PEO), to the retorted packages with totally blocked holes greatly improved the reliability of the instrument and reduced the testing time. The percentage of detected packages with totally blocked microholes with diameters between 30 and 60 μm was improved from 10–55% without PEO to 83–100% with PEO added to the package. © 1997 John Wiley & Sons, Ltd.     

Non-destructive Evaluation and Development of a New Wire Rope Tester Using Parallely Magnetized NdFeB Magnet Segments

A new wire rope tester based on principle of magnetic flux leakage is constructed. Two rings of NdFeB are cut in axial direction into 32 equal arc segments such that each arc segment subtends an angle of 22.5° at the centre. These arc segments are then parallely magnetized in magnetizer. A ferromagnetic cylinderical yoke is constructed by hinging two ferromagnetic half cylinders along one axial edge. A fixture consisting of a wooden square base, wooden mandrel, stepped and slotted Aluminium cylinder and Aluminium fillers is made to assemble the NdFeB magnets in a ring on both the ends of the ferromagnetic yoke. A Hall effect sensor is instrumented inside the yoke in the middle at radial distance of 34 mm from the axis of the yoke. A ferromagnetic wire rope with a defect is inserted in the novel wire rope tester. It has been successfully shown by performing Non-destructive testing that whenever a defect in a wire rope passes below the Hall-effect sensor instrumented in the wire rope tester developed in this work, a signal is generated indicating the defect.     

Asics failure analysis using two complementary techniques: External electrical testing and internal contactless laser beam testing

Functional tests with an electrical tester have revealed defects in an ASIC. Results analysis leads to incriminating different areas of the layout. A laser beam tester localizes the logic operator responsible for the dysfunction observed with the electrical tester.     

A CDM-only reproducible field degradation and its reliability aspect

Simulated electrostatic discharges (ESD) according to the human body model (HBM) and the charged device model (CDM) were compared in their ability to reproduce a leakage degradation observed in the field. Only CDM successfully reproduced the electrical and the physical failure signature in the input inverter of the active circuitry. A home-built CDM tester was used to degrade a significant number of input pins for a reliability or latency study. An experimental investigation of the impact of this degradation on reliability showed that the degraded devices are latently damaged. They have input leakage currents still within specification, but show a highly increased sensitivity to electrical overstress and to ESD stress according to the human body model with a 100 per cent correlation to the CDM degradation. A standard burn-in test showed that they can cause early failures. The degradation is caused by a damage in the gate oxide of an input transistor, and the latent failure is caused by a ‘breakdown’ of the damaged oxide. Latency was shown to appear systematically.     

高效、超高效滤料性能测试台的研制

研制了高效、超高效滤料性能测试台,采用蒸发冷凝方法（即热ＤＯＰ）,对于研究滤料性能具有重要意义,为滤料性能测试提供了新的标准方法。本文详细介绍了本测试台结构、性能及其应用。     

完善对滚筒反力式制动检验台的“检定”

分析了同一辆机动车在不同型号的制动台上由相同检验员检测,会得到不同的结果的原因。通过"机械"或"电子"方法对滚筒反力式制动检验台进行"模拟制动力"加载,经实验验证,是对滚筒反力式制动检验台原"静态检定"工作的一种有效、可靠的"完善"和"弥补"。通过"模拟制动力"加载试验,能发现滚筒反力式制动检验台或计算机联网中存在的问题。提出滚筒反力式汽车制动检验台在生产、使用中应注意的问题。     

Flowability measurements of pharmaceutical powder mixtures with poor flow using five different techniques

Four different tablet formulations for direct compression with poor flow properties were tested regarding flowability using five different techniques: Hausner ratio, avalanching behavior, powder rheometer, uniaxial tester, and Jenike tester. In addition, the behavior of three of the formulations during emptying of the mixer and tableting was observed and compared to the results of the flowability measurements. The rank order correlation of the formulations was generally the same with all techniques. The flow properties measured by the different techniques reflected the behavior during processing of the powder mixtures.