一种油料电导率仪的自动检定方法

针对油料电导率仪批量检定的需求,采用LabVIEW软件结合直流模拟电导装置,完成了对油料电导率仪自动检定系统的研究.采用GPIB接口电路把直流模拟电导装置和计算机控制接口连接,通过控制软件使直流模拟电导自动输出检定标准值给被检仪器.该方法具有使用方便,自动记录检定结果,降低外界干扰的特点,能够更好地满足批量检定和检验的需要.     

碳纳米管电导率的介质谐振器法测量研究

采用介质谐振器法测量碳纳米管在微波频段下的电导率.本文介绍了利用介质谐振器法测量碳纳米管电导率的理论模型和测量装置,给出了利用该装置测得的一系列测量结果,并对其不确定度进行了分析.     

准确度为万分之五的流量标准装置系统的分析

流量测量是民航油料行业经营、管理必不可少的手段之一。流量参数是计算加油量的重要参数之一。目前，民航油料系统普遍采用准确度为of％的二等标准流量计对准确度为0．2％的工作流量计进行量值传递，而准确度为0．l％的二等标准流量计的溯源问题始终难于解决。为了统一民航油料流量量值、开展量值传递、满足民航油料事业的发展对流量测量的要求，中国航空油料华北公司建立了准确度为万分之五的流量标准装置。装置的组成及工作原理1．标准装置的原理图（见右图）。2．标准装置的工作原理门）被检流量计测得的体积值的确定该装置是采用比较法…     

太阳能光伏发电系统的数据监测研究

设计了一种自动的、可以实时检测、记录以及传输的太阳能光伏发电系统的数据检测装置,包括五个模块:电源模块、数据采集模块、数据处理模块、显示模块、无线通信模块。该装置不仅可以实时检测光伏发电组件的环境参数,而且可以把采集到的参数通过无线传输发送到远程的控制台,进行记录处理分析。     

接触式热流计校准装置的研制

该接触式热流计校准装置是基于保护平板法进行研制,采用标准热流密度对热流传感器进行校准。该装置主要由测量、控制、温度采集以及数据分析四个主要模块组成,通过各个模块的设计,保证了该装置的精确度。通过对不同温差、不同试样厚度上的实验数据进行分析,从而找出最优温差以及合适的隔热材料厚度,有效解决了计量部门和节能监测机构热流计量值无法溯源的问题,证实了该校准装置的精度在要求的范围内。     

无引线温度测量模块设计

针对温度场测量中使用常规温度传感器引线不方便的缺点,设计了一套无引线温度测量模块。该模块具有测量精度高、无需引线、使用方便的特点。测量模块配接热电阻传感器,利用参考电阻比例测量技术,大大提高了测量稳定性。测量模块采用真空隔热蓄热技术,在-65~200℃温度范围内正常工作不少于2 h,可满足该温区真空试验罐、热压罐,或其他密闭试验装置、大空间实验装置等温度场均匀性测量的需求。     

现场真空校准装置的设计

基于客户提出的在工作现场对真空计进行校准的切实需求,研究并设计了现场真空校准装置。该装置主要由供气和进样模块、抽气模块、压力衰减模块、压力测量与校准模块、烘烤模块等五部分组成。考虑到现场环境对真空计的影响和校准装置易于携带、小型化的要求,设计中采用了模块化分体式结构,复合了静态比较法、动态比较法和压力衰减法等真空校准方法。可根据不同的校准需求,选配不同的模块和方法实现对真空计的校准。现场真空校准装置预计达到的技术指标是,校准范围为10-4～105Pa,合成标准不确定度小于7%。     

无线测温装置散热及提高准确度的设计

本文主要介绍了一种提高无线测温装置测温准确度及散热的设计方案。该方案主要是给无线测温装置增加了隔离散热结构及独立温度传导结构。其中,独特的散热设计有效降低了在高温环境下或者测量高温物体时测温模块的内部温度,使测温装置能够在允许的温度范围内可靠工作,并提高了无线测温装置电池的使用寿命;独立的温度传导设计使测温部分与装置外壳隔离开,从而有效的增加了装置的测温准确度。     

电客车速度表、速度传感器综合校准装置的研究

电客车速度表和速度传感器是轨道交通重要的计量器具,其计量性能的好坏直接关系运行安全与否。电客车速度表、速度传感器综合校准装置主要由标准转速模块、信号发生模块和控制单元组成。标准转速模块可提供最大允许误差为1RPM的标准转速,对电客车速度传感器进行校准,信号发生模块可直接模拟各种速度传感器输出信号,对电客车速度表进行校准,该装置亦可对电客车的速度测量系统(速度表+速度传感器)整体进行校准,从而保证电客车速度测量的准确。     

血液透析机校准装置透析液电导率示值误差测量值的不确定度评定

本文阐述了血液透析机和血液透析机校准装置中测量透析液电导率参数的测量方法,重点对透析液电导率示值误差测量值的不确定度进行评定。     

A new method for online measurement of the concentration of working fluids in absorption refrigeration systems

This paper proposes a new method for online measurement of the concentration of working fluids in absorption refrigeration systems: electrical conductivity is measured to determine the concentration of the solution. Compared with the common density-concentration method, electrical conductivity-concentration method has the same accuracy but helps to save cost when applied in absorption systems with ammonia–salt solutions. This novel method is also suitable for systems with traditional working fluids like water–lithium bromide solution. Electrical conductivities of ammonia–lithium nitrate, ammonia–sodium thiocyanate and water–lithium bromide solutions were measured between (293.15 and 333.15) K, using an Industrial Conductivity Meter. The ammonia mass fraction varied from 0.35 to 0.48 for ammonia–lithium nitrate solution and from 0.35 to 0.50 for ammonia–sodium thiocyanate solution. For water–lithium bromide solution, the mass fraction of lithium bromide was within the range of 40%–60%. The experimental data were correlated as a function of temperature and composition using the extended Casteel–Amis equation. In addition, correlations of refrigerant mass concentration as a function of electrical conductivity and temperature of the solution are proposed.     

Electrical conductivity measurements of nanofluids and development of new correlations

In this study the electrical conductivity of aluminum oxide (Al2O3), silicon dioxide (SiO2) and zinc oxide (ZnO) nanoparticles dispersed in propylene glycol and water mixture were measured in the temperature range of 0 degrees C to 90 degrees C. The volumetric concentration of nanoparticles in these fluids ranged from 0 to 10% for different nanofluids. The particle sizes considered were from 20 nm to 70 nm. The electrical conductivity measuring apparatus and the measurement procedure were validated by measuring the electrical conductivity of a calibration fluid, whose properties are known accurately. The measured electrical conductivity values agreed within +/- 1% with the published data reported by the manufacturer. Following the validation, the electrical conductivities of different nanofluids were measured. The measurements showed that electrical conductivity of nanofluids increased with an increase in temperature and also with an increase in particle volumetric concentration. For the same nanofluid at a fixed volumetric concentration, the electrical conductivity was found to be higher for smaller particle sizes. From the experimental data, empirical models were developed for three nanofluids to express the electrical conductivity as functions of temperature, volumetric concentration and the size of the nanoparticles.     

Contactless Electrical Conductivity Measurement of Electromagnetically Levitated Metallic Melts

A facility for noninvasive measurements of the electrical conductivity of liquid metals above and below the melting temperature is presented. It combines the containerless positioning method of electromagnetic levitation with the contact-less technique of inductive conductivity measurement. Contrary to the conventional measurement method, the sample is freely suspended within the measuring field and, thus, has no exactly predefined shape. This made a new theoretical basis necessary with implications on the measurement and levitation fields. Furthermore, the problem of the mutual inductive interactions between the levitation and the measuring coils had to be solved.     

pH sensitive multiwalled carbon nanotubes

The CNTs-based sensors have received considerable attention because of their outstanding properties, such as faster response, higher sensitivity, and lower operating temperature. And we expect that CNTs-based electrochemical sensors offer substantial improvements in the performance of pH sensing device. This letter reports experimental results that demonstrate the pH sensing capability of the multiwalled carbon nanotubes (MWCNTs) film by using the thermal chemical vapor deposition (thermal CVD). It was found that electronic properties of MWCNTs can be changed by the introduction of different pH value solutions. The absorption of the hydroxide in pH buffer solution changes conductivity of the MWCNTs. We observed in situ measurement of electrical conductivity by cycling solution range from acid to base.     

Noncontacting electrical conductivity sensor for remote, hostileenvironments

A device for measuring the electrical conductivity at the surface of a large or semi-infinite body at centimeter scale has been developed. The right frequency contacting measurement uses single turn transmitter and receiver loops to generate and detect eddy currents in the material to be probed. Response is linear in conductivity over the four decades of interest in geophysical investigations. The mechanical design of the sensor makes it insensitive to temperature and pressure changes, and to accelerations, impact, and abrasion. Therefore, it is operable in remote, hostile environments such as deep boreholes     

以物体表面温度推算变导热系数的测试原理及技术

提出了一种根据第三类边界条件下物体表面温度的测定值推算随温度线性变化的物体导热系数的测试原理和方法。利用设计的测试系统对几种材料的导热系数进行了测量和计算。结果表明，测试计算方法简单可行。为测定物体变导热系数提供了一个有效的方法。     

A new Peltier sensor for measuring the thermal conductivity offluids

This paper describes a new sensor and a new method to measure the thermal conductivity of many fluids. The principal advantage of the device is self compensation against temperature brought about by an appropriate choice of the materials. Moreover, because the sensor uses both the Peltier and Seebeck effects, measurements can be carried out with accuracy according to an average temperature increase of the device lower than 5 K. Operation of the device brings about a very low Joule power (5 mW). A coherent design rationale is formulated and the various stages in the technical development of the sensor are delineated. Several cases are discussed with a view to increasing the applicability of the method. Notable applications include thermal conductivity gauges for measuring pressures in high-vacuum systems, tank gauging for liquids featuring fire hazards, and low velocity measurements occurring in natural convection mechanisms. It is expected that the versatility of the device will result in a wide number of industrial applications     

基于USB接口的测硫仪设计

设计了基于USB接口的测硫仪,重点对智能控制器中的电解电流控制模块、炉温控制模块和数据采集模块进行了介绍。利用热电偶实现炉温的测量,采用具有USB接口的微处理器完成测量过程的控制和数据传输任务,并设计了高精度的信号放大和数据采集电路来保证仪器的性能,同时还对测试结果进行了精度分析。结果表明,仪器的测量精度满足国家标准。     

液氦流动速度对温度测量的影响

当测量液体或气体流动时的温度时,温度计所测得的温度为流体的滞止温度,而不是流体的真实温度。为提高测量精度,需对所测量的温度进行修正才能得到流体的真实温度。通过液氦泵获得不同的液氦流速,来研究它对液氦测量温度的影响。描叙了实验的结果及其理论分析,并给出了如何修正测量温度而得到液氦的真实温度。