基于非自动衡器国际建议的独立辅助检定装置研究

针对国际建议OIML R76-1:2006(E)《非自动衡器》中规定的3种"测试标准器"的关系进行分析,对"辅助检定装置"的规定进行详细解读。通过对衡器载荷测量仪装置误差和扩展不确定度的分析评定和实际测试,说明该装置是一种符合R76规定的独立辅助检定装置,可用于对大型衡器进行检定。     

强迫风冷式制动电阻风机探讨

本文提出一种新的装置,对制动电阻风机的设计提供参数。·强迫风冷式制动电阻装置风机设计计算方法通过散热性能及风道系的定性分析和计算,确定在电阻制动额定功率下风机风量、风压,为风机选型提供设计参数。该法对制动电阻装置的设计具有一定的指导意义。     

一种大型衡器快捷的校准方法

文章介绍一种大型衡器方便、快捷的校准方法,着重描述了该方法的基本思路、方法步骤及应满足的一些基本条件.该方法很好地解决了大型衡器校准难的实际问题,实现了大型衡器校准快捷、称量准确的目的.     

一种新型液体流量标准装置衡器标定系统的设计

提出了一种新型的用于质量法液体流量标准装置主标准器——衡器的标定系统,介绍了系统的基本原理——叠加式力传感器法,设计了系统的主要功能结构、技术要求和技术指标,通过与当前国内外大量使用的静重法标定系统的比较和分析,该新型系统适用于质量法液体流量标准装置的衡器标定,并且在大口径装置方面具有明显的使用价值和优势。     

基于单片机的电池内阻测量装置

介绍一种采用双电阻测量电池内阻的方法.根据该方法,研制了一种电池内阻测量装置,它具有结构简单、精度高和稳定性好等特点.文中详细阐述了该装置的硬件组成、硬件和软件设计,给出了电路组成框图和程序流程图.测试结果表明,该装置具有较强的实用性.     

衡器置零装置的要求与测试

2005年10月,国际法制计量组织下发了R76的委员会草案(CD)的修订版本(2nd Committee Draft Revi-sion),有关置零方面的术语、技术要求、试验程序基本没有变化,这反映出国际衡器界专家对衡器置零装置的认识趋向一致和稳定。一、数字指示衡器零点指示装置的测试R76强制性测试程序规定,对数字指示和不带零点跟踪装置的衡器,先调至零以下一个分度值,然后逐次加放相当于1/10分度值的一些砝码,以此来确定零点指示装置显示零点偏差的范围。这里有一个问题,用相当于1/10分度值的砝码怎么能确定出其零点偏差不大于0.25e呢?施加砝码单位是0.1e,测试…     

一种新的跟踪滤波器设计方法及其应用

本文提出了一种基于开关与电阻串联的调制方法,从能量等效的角度给出了开关电阻支路等效电阻的计算方法。讨论了基于开关电阻调制的跟踪滤波器设计方法,采用Proteus对跟踪滤波器的特性进行测试,其结果与理论分析吻合,为跟踪滤波器的实际应用提供了可靠的依据。     

汽油机控制参数的电控与测试研究

以MCS－8098单片机作为中央控制器,设计了一种电控发动机基本控制参数测试装置,利用该装置对汽油机的空燃比和点火提前角等控制参数进行了实际测试。应用测试获得的数据对发动机进行实际控制时,取得了比较满意的效果。     

浅析衡器检定工作

衡器称重设备技术水平与产品质量,涉及到了国家贸易、经济国防建设、科学研究及健康可持续发展等方面。因此,要加强管理衡器检定测试仪器的相关的计量装置校验,构建相关的问题要科学,合理的体系研究,具有积极的现实意义。     

隔振器机械阻抗测试平台的设计

利用机械阻抗理论来设计和验算新型减振装置的隔振效果是工程设计中一种既方便又有效的方法.隔振器作为隔振装置中的关键部件,测量得出隔振器机械阻抗特性为最简单的方法.在测试系统中,隔振器机械阻抗的测试平台是测量结果准确性的保证.本文从机座的优化设计、支撑的合理选配和系统的自动调整等方面详细介绍了机械阻抗测试平台的设计过程及具体实施方法.目前该设备已投入实际应用.     

平衡秤微机配料控制系统

 主要介绍平衡秤微机控制系统的设计方法, 该系统已通过省级鉴定该产品已在水泥厂实际应用, 系统性能稳定可靠, 提高生产效率和产品质量。     

复合材料损伤阻抗和损伤容限的性能表征

复合材料结构的设计要求和使用经验提出了复合材料体系损伤阻抗和损伤容限性能表征的需求。在试验研究的基础上,本文作者指出长期以来一直使用的CAI (冲击后压缩强度) 的物理意义比较含混,有时可能误导材料研究和设计选材,同时提出应分别用典型层压板静压痕力-凹坑深度曲线的最大压痕力F_max来表征损伤阻抗性能,用凹坑深度-压缩破坏应变曲线门槛值CAIT(Compression failure strain After Impact Threshold)来表征损伤容限性能,同时给出了测试方法的建议。      

基于标准表法的精密数字测温仪校准方法

参考流量与电学计量领域利用标准表对仪器进行校准的方法,提出一种采用高精度的测温电桥与高稳定性的直流电阻箱组合作为标准装置,校准精密数字测温仪的方法.用此方法对精密数字测温仪进行校准并进行测量不确定度分析,结果表明在-195 ～660℃氛围内,温度示值误差的合成标准不确定度为0.5 ～0.7 mK.此方法采用的标准器准确...     

Measurement of contact resistance with microampere currents

The design of an instrument for measuring contact resistance is presented. The design incorporates photo-isolated synchronous rectification. The noise in this instrument is suppressed to 0.1 nV, and contact resistance can be measured with low currents of 0.1 to 100 μA. Several types of contacts are measured with this low-current instrument. When the contacts are contaminated, they are likely to indicate higher resistance than that measured at milliampere currents with widely used commercial instruments. The instrument is clearly effective and the measurement with microampere currents is important for estimating contact resistance under conditions close to actual use     

Ultrasonic Instrumentation for Measuring Applied Stress on Bridges

The measurement of applied stress on bridges can provide valuable information on the condition of the structure. The conventional technique for measuring applied stress is with a strain gage. However, strain gages can be time consuming to install because first the surface must usually be prepared. On a bridge, paint removal will most likely be necessary as part of this surface preparation. When dealing with lead-based paints, which are considered hazardous waste, many time consuming removal procedures are required. Because of these factors, a device that measures applied stress without requiring paint removal could be useful. While a “clamp-on” strain gage can also be used to measure applied stress without requiring paint removal, this type of strain gage can not be used on some bridge details, such as webs of I-beams and tops of box girders. An ultrasonic technique using non-contact electromagnetic transducers provides a possible method for applied stress measurement which is not limited by the same factors as those with conventional strain gages. The transducers operate through nonconductive and conductive (lead-based) paint and work on rusted, pitted surfaces. Our previous research developed a technique for measuring applied stresses on bridges with EMATs and included many laboratory tests. This paper describes field applications of the technique on actual bridge structures, as well as additional system testing and instrument calibration in the laboratory.     

舰船设备抗冲击能力的可靠性分析

在进行舰船设备系统抗冲击设计及优化分析中,必须要确定舰船设备的抗冲击能力值,而影响设备冲击响应的多种随机因素使设备抗冲击能力具有随机性。本文提出了考虑各种随机因素影响的设备抗冲击能力可靠性的定义和分析方法,结合神经网络建立了设备冲击响应预测模型,在数值冲击试验基础上,结合Monte Carlo法分析了典型舰船设备抗冲击能力的统计特征。分析方法和结果可为今后舰船设备及系统的抗冲击性能分析、舰船系统抗冲击性能评估提供参考。     

双任务下仪表对新驾驶员视觉前注意影响研究

研究在双任务环境下,仪表盘指针的长度和宽度以及字符颜色等因素对于人员认知过程影响。本研究采用实验方法,对被试人员操作过程中反应时和正确率进行数据分析。结果显示,指针宽度和字符颜色对于被试反应时间具有显著影响;指针长度对于被试操作正确率具有显著影响。研究结果可给驾驶过程认知模型建立提供数据支持,可以帮助仪表设计人员更好的进行仪表界面设计和测评工作。     

Pipe Weld Investigation using Shearography

Abstract: In this paper the full-field optical technique of shearography is used to fully characterise the surface strain of the region around a welded joint in a pipe. Shearography is an interferometric optical technique sensitive to displacement gradient, a parameter that is closely related to the surface strain. The surface of the material at a welded joint is uneven, but measurements may still be performed using full-field non-contact optical methods. In this paper the authors present a multi-component shearography system, which measures the in- and out-of-plane displacement gradient components by determining three non-orthogonal displacement gradient components and performing a coordinate transformation. To compensate for non-planar object surfaces the coordinate transformation procedure incorporates a correction for the object shape, measured using the same apparatus. The instrument was used to determine the six components of displacement gradient, thereby fully characterising the surface strain. In comparison with resistance strain gauges, an accuracy of ±11 μɛ was achieved over a limited measurement range.     

Experimental Study on the Effect of Strain Cycles on Mechanical Properties of AISI 1022 Steel

Abstract: The effect of cyclic loading on various mechanical properties of AISI 1022 steel was investigated in this study using laboratory‐based experimental method. Groups of specimens were tested in push‐pull strain‐controlled cyclic loading. Some of these specimens were tested to failure in pure fatigue tests. For the remaining specimens, cyclic loading tests were terminated at a specific number of cycles and these specimens were then tested to failure in quasi‐static tension. It was found that the strength increased, while the ductility and toughness decreased because of applications of strain cycles. As reduction in ductility weakens plastic strain resistance, and drop in toughness reduces resistance to fracture of this steel, the quasi‐static mechanical behaviour is expected to change as a consequence of application a certain number of strain cycles. This study therefore suggests that these changes in mechanical properties have to be contemplated in the associated design processes.     

基于AHP-FCE的康复训练仪设计

目的 为了提高中风和脑损伤患者在康复训练过程中的效率,对康复训练仪的设计做了一系列目标优化.方法 使用层次分析法(AHP)以及模糊综合评价(FCE)的方法,建立针对于康复训练仪的设计评价模型,围绕康复训练仪设计评价和方案决策两方面进行了研究.在设计评价方面,将康复训练仪的设计拆解成为不同的层次、不同的要素,采用定性和定量相结合的分析方法,计算并排序每个设计要素的权重.在方案决策方面,依据上阶段计算出的各要素权重值排序,运用模糊综合评价法对康复训练仪的设计方案进行评分,得到最完善、最优型的设计方案.结论 通过引入层次分析法和模糊综合评价在前期设计过程中的应用,能够有效地避免产品设计中的主观因素,为设计决策以及设计评价提供客观依据.