一种可用于溶解氧测定的光纤氧传感器

用Ru(bpy)3Cl2为指示剂，研制一种能用来测定溶解氧的光纤氧传感器，该传感器的响应时间小于30S，检测下限为0．5mg/L，检测准确度0．01mg/L，并具有较强的抗干扰能力，较好的重复性和稳定性，可用于对环境水质的在线监测。     

测量绝缘纸板微水分分布的电容阵列式传感器

由于变压器绝缘纸板中的微水分影响其介电特性,用介电测量方法可以得出纸板内的微水分分布。为此,开发了一种16个边缘场电容测量单元的阵列式微水分传感器,通过轮流使用各测量单元可获得被测纸板纵向分布的对应复介电系数,进而转换为各处的水分质量分数,由该传感器构成的测量系统可以用于纸板干燥过程中在线监测纸板的水分分布变化,其使用效果得到试验证实。介绍了该传感器的原理、结构及测量系统的构成。     

基于荧光猝灭原理的溶解氧浓度检测系统的设计

介绍了荧光猝灭原理,设计了一种基于荧光猝灭原理的溶解氧浓度测量系统,解释了系统检测原理,给出了系统结构图及关键部分的电路设计.最后给出了相关的实验结果并进行了分析.实验表明,系统测量精度为0.01 mg/L,响应时间少于30ms,具有较好的响应速度、精度以及稳定性.     

Simultaneous determination of oxygen transport characteristics of six membranes by hexagonal dissolved oxygen sensor system

In the present study, a hexagonal sensor system composed of a six port measurement device and six different cathodes with one common anode was developed for simultaneous determination of oxygen permeabilities or diffusivities of six different membranes. To minimize experimental variations caused by geometrical differences among six individual electrodes, the current output of each electrode was divided by individual correction factors determined by standardization with a typical membrane of fluorinated ethylene propylene (FEP). The hexagonal sensor system was then used to simultaneously determine the oxygen transport characteristics such as permeabilities or diffusivities of six different polypropylene membranes. The present study showed that a newly developed hexagonal dissolved oxygen sensor system can be used for simultaneous measurement of oxygen transport characteristics of six different membranes.     

极谱法溶解氧传感器输出稳定性研究

针对极谱法溶解氧传感器在长期检测过程中存在的输出稳定性差的问题,结合极谱法溶解氧传感器的结构与检测机理,分析了影响极谱法溶解氧传感器输出稳定性的因素.研究表明:氧化-还原电位偏移、透气膜的污染和形变、温度及搅拌均会导致输出不稳定.针对每种影响因素提出了解决办法,提高了稳定性,满足了长期在线监测水质的需要.     

Fabrication of miniature Clark oxygen sensor integrated with microstructure

A miniature Clark-type oxygen sensor has been integrated with a microstructure using a novel fabrication technique. The oxygen chip consists of a glass substrate with a three-electrode configuration, which is separated and connected by a groove, and a poly(dimethylsiloxane) (PDMS) container with an immobilized PDMS oxygen-permeable membrane. The assembly of the different substrates only uses the O₂ plasma bonding technique, and the fabrication temperatures do not exceed 95 °C. Characteristics of the miniature sensor include the fastest response time of 6.8 s, good linearity with a correlation coefficient of 0.995, and a long lifetime of at least 60 h. The present miniature Clark oxygen sensor can be readily integrated with a microfluidic system to form a μ-TAS.     

一种新型高精度溶解氧传感器的设计

采用极谱式溶解氧电极,以低功耗、高稳定性能的NEC单片机为核心处理器,设计了一种新型高精度溶解氧传感器。详细介绍了传感器的工作原理、NEC单片机的各项性能参数、硬件结构以及电路分析、软件设计。针对极谱式溶解氧电极激化时间长的缺点,提出一种实用的解决方案,大大缩短了测量时间。采用18位的A/D转换器与高精度的仪表运算放大器,提高了测量精度。     

基于超声波传感器阵列的轿车开门预警系统

为了防止轿车乘客下车开门时与后方接近的物体发生碰撞,并降低此类事故发生的概率,提出了一种基于超声波测距传感器阵列的轿车开门防撞预警系统.基于相关数据统计,根据城市道路行驶安全速度的相关规定建立数学模型;利用超声波测距原理和数据处理算法,将车辆左后方接近的物体的距离转化为实时速度,并与阈值进行对比,超过阈值系统报警;通过STM32单片机控制系统的各个模块实现防撞预警功能.通过测试对象分别为行人、自行车、电动车和摩托车的实际测试,系统准确度分别为100％、89.7％、90.3％和93％.测试结果表明,系统在轿车开门防撞预警方面有着一定的效果,可以有效降低乘员开门下车发生碰撞事故的概率.系统具有成本低、精度高、鲁棒性强、探测范围可调、可移植性强、性价比高的优点,具有良好的市场前景以及较大的发展空间.     

Micromachined dissolved oxygen sensor based on solid polymer electrolyte

A silicon microprobe to measure dissolved oxygen levels is described. The sensors are prepared by overlaying platinum thin film electrodes with a solid state proton conductive matrix (PCM) coating. The platinum thin film electrodes are fabricated on silicon substrates by standard photolithographic techniques while the PCM coating is achieved by drop-casting methods. The size and materials of the device make it potentially suitable for medical implantation. The devices are tested in deionized water (DI water), phosphate buffered saline (PBS), and bovine blood serum (BBS). Through linear sweep voltammetry (LSV), single devices are shown to have decent performances in terms of long term stability, reliability, hysteresis, linearity, and sensitivity. Variations among different devices are characterized and correlated. The simplicity and cost effectiveness of the fabrication and packaging procedures and the decent in vitro performances of these devices make them good candidates as miniaturized, disposable, and implantable dissolved oxygen sensors for biological and biomedical use.     

Contact CMOS imaging of gaseous oxygen sensor array

We describe a compact luminescent gaseous oxygen (O₂) sensor microsystem based on the direct integration of sensor elements with a polymeric optical filter and placed on a low power complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC). The sensor operates on the measurement of excited-state emission intensity of O₂-sensitive luminophore molecules tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ([Ru(dpp)₃]²⁺) encapsulated within sol-gel derived xerogel thin films. The polymeric optical filter is made with polydimethylsiloxane (PDMS) that is mixed with a dye (Sudan-II). The PDMS membrane surface is molded to incorporate arrays of trapezoidal microstructures that serve to focus the optical sensor signals on to the imager pixels. The molded PDMS membrane is then attached with the PDMS color filter. The xerogel sensor arrays are contact printed on top of the PDMS trapezoidal lens-like microstructures. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. Correlated double sampling circuit, pixel address, digital control and signal integration circuits are also implemented on-chip. The CMOS imager data is read out as a serial coded signal. The CMOS imager consumes a static power of 320 μW and an average dynamic power of 625 μW when operating at 100 Hz sampling frequency and 1.8 V DC. This CMOS sensor system provides a useful platform for the development of miniaturized optical chemical gas sensors.     

一种检测NO气体的光纤传感系统

建立了一套对 ＮＯ气体检测的光纤传感器系统,得到了ＮＯ气体对光的吸收谱和光波长为 ４００ｎｍ时不同气体体积分数的吸收特性,实验结果表明在一定条件下ＮＯ气体体积分数与系统的输出信号成线性关系。该系统的响应迅速,恢复时间短。     

基于氧传感膜荧光特性的溶解氧传感器研制

基于氧传感膜荧光特性研制了一种低成本、小型化的溶解氧传感器.对传统氧传感膜的制备方案进行了优化,结合其透光特性对所制备的传感膜优劣进行甄别和选优.在此基础上,重点研究了水温、浸泡时间等因素对传感膜荧光发射强度的影响.为提高溶解氧的测量精度,设计了一种45°角斜面传感器探头结构,有效降低了水中气泡对溶解氧的测量干扰.实验结果表明:该溶解氧传感器能够准确测量0 ～20 mg/L范围内的待测液体的含氧量,检测误差为±2％,检测精度达±0.1 mg/L,在工农业生产、水质监测及水产养殖等方面具有较好的应用前景.     

Silicon-based miniature sensor for electrical tomography

The paper describes the fabrication of a novel miniature sensor for electrical tomography. The sensor comprises a number of copper electrodes that are fabricated around a small hole that is etched through a silicon wafer. Copper electrodes are electroplated to fill channels that are formed in thick photo-resist on top of the silicon wafer. Electrodes with a thickness of 60 μm, surrounding a hole of diameter 300 μm, have been realised. Initial measurements have been made using a commercial LCR meter applied to an eight-electrode sensor and images of a 80 μm diameter wire have been obtained. Future work will consider the integration of measurement circuitry alongside the electrodes in order to reduce parasitic capacitances.     

振弦式传感器测频系统的设计

根据振弦式传感器工作原理而设计的测频系统主要由手持式测频仪和PC计算机组成。测频仪采用直读式测频法测量振弦式传感器的输出频率,并将测量值和传感器特性参数代入固化在其内部的计算公式进行计算,从而实现传感器物理量的现场显示。同时,还可以通过PC计算机的串口将测量数据传给计算机,由计算机对数据进行处理、显示。该系统可大大减轻测量人员和工程技术人员的劳动强度,缩短测量和计算时间,提高测量及计算准确度。     

可测上升流的海流传感器系统设计

针对上升流引起的微弱信号在A/D转换前容易被传感器系统噪声所淹没的问题,将滤波、放大和A/D转换电路采用集成芯片AD7195处理,减少分立器件噪声,AD7195芯片内部集成差分放大器、交流激励和数字滤波器,同时具有24位高精度A/D转换功能.通过搭建实验装置,采集数据和分析,测试了系统准确度.实验结果表明:该系统能够识别输入信号的误差为±0.4μV,满足设计要求.     

差动变压器式位移传感器检测系统研究

介绍了差动变压器位移传感器的结构和原理,分析了零点残余电压产生的原因以及对差动变压器位移传感器灵敏度、线性度、精度的影响,并给出了有效的解决方法。应用LabVIEW对差动变压器副边线圈的差动输出信号进行检相、滤波等处理。结果表明:与其他检测方法相比,该差动变压器位移传感器具有更高的灵敏度和更良好的线性度。     

基于微型CMOS传感器模拟射击训练系统

所研制的是一种适宜于国家射击队清华班使用的模拟射击训练系统,采用微型互补金属-氧化物-半导体(CMOS)高速摄像头来接收目标靶上4只红外LED发出的红外光线,以确定瞄准点在目标靶上的实际位置,并且能实时记录瞄准和射击过程.CMOS高速摄像头体积小,质量轻,能够科学模拟射击训练过程;设计了友好的人机交互界面,解决了训练过程中数据可视化的问题.实验结果表明:CMOS系统性能稳定,达到了设计要求.     

基于气体传感器阵列的易挥发化学品判别系统

利用气体传感器阵列结合判别软件,可用于气体的定性识别。本系统采用气体传感器MQ211组成阵列,结合气室和必要的电路,设计了实时数据采集判别系统,介绍了判别系统的构成与实验过程,实验结果表明:本系统能准确判别多种易挥发化学品。     

A privacy-preserving and unobtrusive sitting posture recognition system via pressure array sensor and infrared array sensor for office workers

Sitting posture recognition is essential in preventing work-related musculoskeletal disorders (WMSDs). WMSDs are of huge concern for office workers whose working process is averagely 81.8% sedentary. Prevailing studies have utilized cameras, wearables, and pressure sensors to recognize sitting postures. The cameras and wearables can achieve accurate recognition results, while personal privacy concerns and inconvenience for long-term use impede their adoption. Meanwhile, the pressure sensors are privacy-preserving and convenient. However, they cannot accurately recognize the sitting posture with different states of the trunk, head, upper extremity, and lower extremity. Considering the pros and cons of those approaches, this study proposes a novel privacy-preserving and unobtrusive sitting posture recognition system, which combines a pressure array sensor with another privacy-preserving sensing technology, i.e., an infrared array (IRA) sensor. Moreover, a deep learning-based sitting posture recognition algorithm is developed, which adopts a feature-level fusion strategy and does not require a complex handcrafted feature extraction process. Based on the ergonomics studies, ten daily sitting postures with the states of different body parts are selected. This system achieved an overall 90.6% accuracy using the leave-subject-out validation approach based on the self-collected dataset from 21 subjects. It has a great potential for privacy-preserving and unobtrusive related applications for sitting posture management.