A low-cost in-situ CO_(2) sensor based on a membrane and NDIR for long-term measurement in seawater

The multi-point simultaneous long-term measurement of CO_(2) concentration in seawater can provide more-valuable data for further understanding of the spatial and temporal distribution of CO_(2).Thus,the requirement for a low-cost sensor with high precision,low power consumption,and a small size is becoming urgent.In this work,an in-situ sensor for CO_(2) detection in seawater,based on a permeable membrane and non-dispersive infrared(NDIR)technology,is developed.The sensor has a small size(Ф66 mm×124 mm),light weight(0.7 kg in air),low power consumption(<0.9 W),low cost(<US$1000),and high-pressure tolerance(<200 m).After laboratory performance tests,the sensor was found to have a measurement range of(0–2000)×10^(-6),and the gas linear correlation R^(2) is 0.99,with a precision of about 0.98%at a sampling rate of 1 s.A comparison measurement was carried out with a commercial sensor in a pool for 7 days,and the results showed a consistent trend.Further,the newly developed sensor was deployed in Qingdao nearshore water for 35 days.The results proved that the sensor could measure the dynamic changes of CO_(2) concentration in seawater continuously,and had the potential to carry out long-term observations on an oceanic platform.It is hoped that the sensor could be applied to field ocean observations in near future.

Research Surveys of Electrochemical Sensors for in-situ Determining Hydrogen in Steels

The principle, construction and application of two types of electrochemical sensors-amperometric and potentiometric are surveyed. Both types of sensors are very sensitive to changes in temperature. The accuracy of hydrogen measurement depends on both the precision of sensors developed and the reliable technique of installation and security of sensors. The two types of sensors have been used for in-situ determining hydrogen permeated in steels owing to a corrosive reaction, a hydrogen gas circumstance at elevated temperatures and high pressure or also a pretreatment process such as pickling and plating process, etc.

The Influence of Quantum Technology on the Development of Metrology and Measuring Science

In the new century, quantum technology has developed rapidly and has been applied in many fields. As an important aspect of the aerospace science, metrology and measuring science is a field which is influenced by the quantum technology dramatically. The new generation of the International System of Units will be redefined on the basis of the quantum theory. More and more new sensing techniques are developed taking into account quantum principles. In this paper, the influence of quantum technology on metrology and measuring science is introduced.

Hamamatsu’s Products for Optical Inspection,Metrology and Monitoring to Improve Yield and Accuracy for Semiconductor Processes

Pursuing small critical dimensions(i.e.14 nm or below)and high integration bring us lots of physical defects causing low yield and functionality failures for foundries.Under this circumstance,inspection,metrology and monitoring technologies are unprecedentedly vital for development of semiconductor industry.Optical and electron beam solutions are the most common two methods in semiconductor manufacturing.Hamamatsu Photonics is now aiming at optical inspection,metrology and monitoring systems market by providing light sources,photodetectors and failure analysis systems for semiconductor equipment manufacturers,foundries and research institutions.In this paper,features and potential applications of light sources,photodetectors(like image sensors,photomultiplier tubes/modules,silicon photomultipliers(modules),(avalanche)photodiodes(arrays)and so on),with the wavelengths ranging from UV to Infrared,are mainly discussed.In addition,Hamamatsu’s star product– failure analysis system to quickly locate faults or defects are introduced.In conclusion,Hamamatsu Photonics is dedicated to develop large varieties of light sources and optical sensors/detector/modules along with failure analysis systems and willing to improve the development of semiconductor and related industries,especially in China.

基于物理水平基准的组合式高程测量方法

针对空间坐标点相对于测量基准的高程测量准确性问题,提出一种基于物理水平基准的组合式高程测量方法。利用激光三角测量原理及其测量光路的几何特性,搭建了物理水平基准的高程测量系统,在朗伯散射光场中,分析了倾角变化对激光光能质心偏移量的影响,建立了相应的误差修正模型,利用倾角传感器实现了高程测量的倾角误差补偿,自主研制了标定平台对本文提出的高程测量系统进行标定验证试验。结果表明:本文提出的组合式高程测量方法能够在500 mm测量量程下将重复性测量误差控制在±20μm的波动范围内,相较于单一激光位移传感器测量方式,其组合式高程测量误差波动量大幅度降低,能够适应空间坐标点在任意姿态下的精准测量,有效改善激光位移传感器在高程测量领域的性能,使其测量结果更为真实有效。

柔性超导电路制备工艺技术研究

超导转变边沿探测器是坎德拉单位量子化复现和单能X射线量子计量的核心器件。大规模超导转变边沿探测器阵列探头的信号读出需利用柔性超导电路将信号传输至探头侧面的超导量子干涉器件。柔性超导电路是将超导信号线制备在柔性聚酰亚胺衬底上以实现信号低热导率、无阻传输。以硅片作为临时支撑,电子束蒸发100 nm Cr膜作为剥离牺牲层。非光敏聚酰胺酸旋涂在Cr膜上固化后,通过紫外曝光、溅射薄膜沉积和剥离等工艺制备Nb/Al薄膜传输线结构,利用Cr膜高应力特性将聚酰亚胺薄膜从硅片上剥离,湿法腐蚀Cr膜完成柔性超导电路的制备。测试的40根Nb/Al传输线的超导转变温度T_(c)为8.91~9.02 K,剩余电阻比r_(RR)为5.83~6.96。温度为8 K时,38根传输线临界电流I_(c)超过1 mA;温度为4.2 K时,所有样品I_(c)均超过1 mA,其中有25根传输线I_(c)超过10 mA,满足超导转变边沿探测器阵列测试需求。

室内环境甲醛气体检测技术的研究进展

以甲醛标准物质量值溯源方式不同展开讲解,分别重点介绍了室内环境甲醛检测所常用分光光度法、气体传感器技术,以及结合未来低碳计量发展前景而着重介绍了光腔衰荡光谱技术相关内容。列举了较为常见典型技术并从基础原理、反应机理和实际应用等方面进行讲解,并分析与总结相关检测技术的优缺点以及探讨了服务于低碳计量的可行性与未来前景,进而有助于完善甲醛量值溯源体系,为满足低碳计量所需微痕量甲醛气体检测工作而提出可行的方案。

光谱共焦传感器多参数高准确度校准

针对高准确度光谱共焦传感器缺乏相应校准装置及方法的问题,提出了一种基于激光干涉测量的校准方法,并研制了相应的校准装置。一方面,提出了一种波长倍数间隔测量法,通过位移反馈控制将位移间隔设置为激光波长的整数倍,以减小激光干涉仪非线性误差对测量的影响;另一方面,提出了测点修正算法,消除了受检点处位移标准值因校准装置定位准确度限制不重合对测量的影响。实验结果表明:在0~100μm的测量范围内,示值误差为±23 nm,重复性为5 nm,示值误差测量结果的扩展不确定度U_(2)=7.0 nm(k=2)。构建的校准装置在0~50 mm的测量范围内的示值误差测量结果不确定度为U_(1)=3.0 nm+2×10^(-7)L(k=2)。

一种静重式微型测力传感器校准装置的研究

基于微型测力传感器特殊的使用环境和结构特征,本文提出针对性的校准方案,介绍了一种静重式微型测力传感器校准装置,该装置由力值砝码、平衡力臂、框式机架、自定心夹持装置、平衡游码等组成。经测试验证,校准装置的测量范围为1N~1000N,测量不确定度不大于1×10^(-3),可对0.3级及以下等级的微型测力传感器开展量值传递,有效解决了该类型传感器的校准需求。

隔离开关合闸状态的非接触自动检测方法

为了提升隔离开关合闸状态自动检测效果,采用了基于激光位移传感器的隔离开关合闸状态非接触自动检测方法,使激光位移传感器的分辨率达到最大值,优化了激光位移传感器的光学参数,提升了其位移测量精度;通过光学参数优化后的激光位移传感器,采集隔离开关轮廓曲线,得到隔离开关轮廓曲线采样点集;利用最小二乘法拟合隔离开关轮廓曲线采样点的椭圆方程,并计算隔离开关导电臂与水平方向的夹角;当导电臂夹角处于规定夹角区间内,则判定合理开关合闸到位,完成隔离开关合闸状态非接触自动检测。结果表明,该方法计算的前、后导电臂夹角分别在0.4°与0.5°左右,均低于夹角规定区间。这一结果对实现隔离开关合闸状态非接触自动检测是有帮助的。

Experimental Study of Non-Destructive Approach on PEMFC Stack Using Tri-Axis Magnetic Sensor Probe

In this paper, the current distribution in a 300-W-class PEMFC stack was investigated in order to determine the operating state of the stack. Measurements of the magnetic field were performed on several cells in the stack. The vector of the magnetic field expressed the direction of the macroscopic current, which was from the anode side to the cathode side. This direction matched the polarity of the stack. In the measurement results, current distributions differed among cells;each cell had a different performance. Furthermore, we have tried to evaluate faults, such as flooding, by measuring the magnetic field and variations in the voltage.

基于激光点云数据的叶片型面三维重构

在四坐标叶片型面检测基础上,提出基于激光点云数据的叶片型面三维重构方法。激光位移传感器对叶片型面进行多视角扫描采样,快速采集叶片型面海量点云数据。运用由点到线到面的数学建模原理,先基于端点一阶导矢连续法拟合出光顺NURBS曲线,再依据分片能量法构建辅助曲面拟合出光顺NURBS曲面,最后对分片NURBS曲面进行统一描述,构造出精确光滑的叶片型面,实现叶片型面的三维重构。实验结果表明:采用该方法实现对各类叶片复杂型面的三维重构,重构误差均<0.015 mm,能够满足精密零件的测量需求。

基于Choi-Williams分析与神经网络的两相流流型识别

提出一种基于Choi-Williams分析和神经网络的流型识别方法。使用阵列电导传感器获取垂直上升管道气液两相流流型信息,并将多元测量数据进行去噪和降维处理,进一步采用Choi-Williams分析将其转换为时频谱图,并构建数据集。分别搭建CNN、VGG-16和ResNet-18网络模型,将不同流型的时频谱图作为网络输入进行训练、测试。识别结果表明,Choi-Williams分析可以有效提取不同流型信号的特征,3种网络均具有较高的识别精度,其中ResNet-18网络准确率最高,平均流型识别率达99.4%。

基于最小二乘法的海洋温度传感器动态响应特性测量不确定度研究

针对海洋温度传感器动态响应特性测试需求,通过水文传感器时间常数测量装置对典型海洋温度传感器进行了时间常数测试,分析了时间常数特性,并根据测量原理对基于最小二乘法的时间常数测量结果进行了综合全面的不确定度研究。结果表明:时间常数与温度阶跃大小无关,不同类型传感器的时间常数与运动速度满足不同的函数关系,可用该函数关系式表征该传感器的时间常数特性;在0.5~3.0 m/s范围内,时间常数测量结果的相对扩展不确定度优于10.2%,与其最大允许误差±10%相当,满足水文传感器时间常数测量装置的性能要求。水槽的温度波动度和均匀性是不确定度的主要来源,营造理想的阶跃环境,保持测试环境工况稳定,能有效减小初始电压和初始时刻引入的不确定度分量,提高动态响应特性的测量精度。

基于激光干涉与电容传感复合校准技术的纳米微动台分辨力评价方法研究

激光干涉仪测量纳米级分辨力时,因环境等因素的干扰测量具有局限性,电容传感器可较好地对抗这种干扰,但存在无溯源性、非线性误差的缺点。为实现纳米级分辨力的量值溯源,保障量值准确性,采用激光干涉仪对电容传感器进行校准,从而形成纳米微动台-电容传感器-激光干涉仪的完成溯源链。通过量值溯源实验可知,在10 nm步进下电容传感器与激光干涉仪测量量值最大偏差为0.8 nm;电容传感器分辨力校准实验中,纳米位移台分辨力为2 nm。上述结果说明此校准方法具有一定的可行性和实用性。

磁悬浮转子真空计转子轴向悬浮建模与优化设计

为满足磁悬浮转子真空计球形转子在真空中的轴向位移测量与悬浮控制需求,针对其同时加载悬浮直流电流和电涡流传感器交流激励的悬浮系统,建立了基于交流电桥结构的交直流耦合的频域模型。采用四阶龙格库塔法解算其悬浮过程的位移响应,结果显示交流激励的加载为磁悬浮系统引入了非线性因素。制作空气磁芯的电涡流传感器线圈,设计测量电路并制作PCB板,实验分析交流激励产生的电涡流对磁悬浮转子真空计转子悬浮控制的影响。通过对线圈半径参数进行优化实现了对交流作用所产生影响的控制,为磁悬浮转子真空计的优化设计提供了理论指导。

Validation of virtual sensor-assisted Bayesian inference-based in-situ sensor calibration strategy for building HVAC systems

For building heating,ventilation and air-conditioning systems(HVACs),sensor faults significantly affect the operation and control.Sensors with accurate and reliable measurements are critical for ensuring the precise indoor thermal demand.Owing to its high calibration accuracy and in-situ effectiveness,a virtual sensor(VS)-assisted Bayesian inference(VS-BI)sensor calibration strategy has been applied for HVACs.However,the application feasibility of this strategy for wider ranges of different sensor types(within-control-loop and out-of-control-loop)with various sensor bias fault amplitudes,and influencing factors that affect the practical in-situ calibration performance are still remained to be explored.Hence,to further validate its in-situ calibration performance and analyze the influencing factors,this study applied the VS-BI strategy in a HVAC system including a chiller plant with air handle unit(AHU)terminal.Three target sensors including air supply(SAT),chilled water supply(CHS)and cooling water return(CWR)temperatures are investigated using introduced sensor bias faults with eight different amplitudes of[−2℃,+2℃]with a 0.5℃ interval.Calibration performance is evaluated by considering three influencing factors:(1)performance of different data-driven VSs,(2)the influence of prior standard deviationsσon in-situ sensor calibration and(3)the influence of data quality on in-situ sensor calibration from the perspective of energy conservation and data volumes.After comparison,a long short term memory(LSTM)is adopted for VS construction with determination coefficient R-squared of 0.984.Results indicate thatσhas almost no impact on calibration accuracy of CHS but scanty impact on that of SAT and CWR.The potential of using a prior standard deviationσto improve the calibration accuracy is limited,only 8.61%on average.For system within-control-loop sensors like SAT and CHS,VS-BI obtains relatively high in-situ sensor calibration accuracy if the data quality is relatively high.

加速度传感器对重力仪振动补偿效果分析

为分析加速度传感器对重力仪的补偿效果,基于NIM-3C绝对重力仪搭建了平台式重力测量实验平台,并用激光测振仪输出信号作为标准信号,通过实验标定了平台式重力测量环境下MSA1000A-02、991B、INV9832-50三种不同型号的加速度型传感器的振动采集性能。实验结果表明,为保证平台式重力测量环境下的重力测量不确定度达到mGal量级,加速度计引入的测量不确定度应在百μGal以内。在平台式重力测量工况下,传感器MSA1000A-02和激光测振仪所测振动(标准信号)的拟合二次项系数极差为2.94μGal,满足平台式重力测量环境的不确定度及带宽等的要求。

光纤压力传感器测量的最小偏差腔长解调算法

在光纤传感技术领域应用基于法珀腔(外腔式法布里-珀罗干涉腔)结构的光纤压力传感器进行气体压力测量时,由于传感器结构决定了腔长动态范围相对较小,需要高分辨率的腔长测量方法。因此针对基于法珀腔结构的光纤压力传感器进行绝对腔长解调算法研究,提出一种高精度最小偏差腔长解调算法,通过将法珀腔光纤压力传感器密封在压力标准源中,对等间隔压力变化产生的不同腔长进行实时解调,实现了气体压力的实时测量。实验结果表明,法珀腔光纤压力传感器腔长值随压差变化呈现出良好的线性关系和重复性,腔长测量的重复性为±1 nm,精度为0.1496%,压力测量的重复性为0.12%,压力测量的精度优于0.5%。

辐照碳化硅测温晶体温度标定试验感温过程分析研究

辐照碳化硅测温晶体是航空发动机研制过程中热端旋转部件温度测量的重要方法,其测量精度依赖于对其温度-缺陷浓度响应关系的精准标定,标定过程可分为温度标定试验、晶体缺陷表征测量、标定曲线建立3个阶段。温度标定试验中,温度场的波动、测温晶体与测温热电偶感温偏差以及非理想因素导致的传热是辐照晶体技术测量误差的重要来源。利用实验和数值方法,研究了辐照测温晶体在温度标定试验过程中不同阶段下主导的传热传质过程,分析了支杆材料的热物理参数、温度过冲以及准热平衡状态下的温度扰动对于测温晶体感温的影响,结果发现测量误差主要由辐射场在轴向方向的不均匀分布所导致,最后对支杆的材料和结构设计提出了相应的改进方案。