电感式带钢检测器工作原理及绝缘故障处理

通过电感式带钢检测器发射线圈绝缘故障处理案例,介绍了相关故障分析、判断及处理方法。

高层建筑中火灾的检测与自控研究(英文)

依据高层建筑火灾性质和特点 ,介绍了高层建筑中用散射光式光电感烟检测器检测火灾的工作原理 ,讨论了自动控制报警的工作过程 .分析比较了设有延时工作过程的感烟探测系统比没有延时工作过程的系统 ,火灾报警的可靠性大大增强 .并编制了自动报警系统计算机程序框图 ,本文讨论的高层建筑中火灾的探测与自控研究 ,对于不同建筑结构和不同要求的火灾控制报警系统具有参考价值和社会经济意义 .图 5 .参 5 .

烟箱缺条金属检测装置

在卷烟产品的装箱过程中,由于设备的高速运行和检测器之间的相互干扰,条烟装箱过程中缺条情况的出现不可避免。论文采用金属检测的方式,设计双侧面全金属检测装置,同时,增设顶部金属检测结构,通过采用扫描检测算法极大地提高了缺条检测装置的准确性,保障了卷烟产品质量,维护企业声誉。

Numerical Simulation and Analysis of Bipolar Junction Photogate Transistor for CMOS Image Sensor

A new photodetector--bipolar junction photogate transistor is presented for CMOS image sensor and its analytical model is also established.With the technical parameter of the 0.6μm CMOS process,the bipolar junction photogate transistor is analyzed and simulated.The simulated results illustrate that the bipolar junction photogate transistor has the similar characteristics of the traditional photogate transistor.The photocurrent density of the bipolar junction photogate transistor increases exponentially with the incidence light power due to introducing the injection p+n junction.Its characteristic of blue response is rather improved compared to the traditional photogate transistor that benefits to increase the color photograph made up of the red,the green,and the blue.

A FAULT DETECTION SENSOR FOR CIRCUIT AGING USING DOUBLE-EDGE-TRIGGERED FLIP-FLOP

In nanoscale technology, transistor aging is one of the most critical problems that impact on the reliability of circuits. Aging sensor is a good online way to detect the circuit aging, which performs during the operating time with no influence of the normal operation of circuits. In this paper, a Dou- ble-edge-triggered Detection Sensor for circuit Aging （DSDA） is proposed, which employs data signal of logic circuits as its clock to control the sampling process. The simulation is done by Hspice using 45 nm technology. The results show that this technique is not case of the detection precision is more than 80% under aging fault effectively with the 8% power cost and 30% sensitive to the process variations. The worst the different process variations. It can detect performance cost.

Determination of Threshold for Energy Detection in Cognitive Radio Sensor Networks

The Internet of Things （loT） is called the world＇ s third wave of the information industry. As the core technology of IoT, Cognitive Radio Sensor Networks （CRSN） technology can improve spectrum utilization efficiency and lay a sofid foundation for large-scale application of IoT. Reliable spectrum sensing is a crucial task of the CR. For energy de- tection, threshold will determine the probability of detection （Pd） and the probability of false alarm Pf at the same time. While the threshold increases, Pd and Pf will both decrease. In this paper we focus on the maximum of the difference of Pd and Pf, and try to find out how to determine the threshold with this precondition. Simulation results show that the proposed method can effectively approach the ideal optimal result.

城市快速道路交通信息采集初探

交通信息采集是交通管理的基础,详尽、及时、准确的数据将保证交通监控的有效可靠.根据对交通控制策略的分析,无论何种策略,如果要发挥作用,必须有充足的信息源作为基础.交通流信息采集是通过安装在路边的交通参数检测设备采集,经过初步处理后形成数字式数据通过通信系统送到监控中心计算机系统.

Design of a Weak Signal Detecting Circuit in the Infrared Spectrum Absorbed Type Gas Sensor

In the infrared spectrum absorbed type gas concentration sensor,voltage signal obtained from the two-channel thermopile infrared detector TPS2534 is very weak.In order to solve this problem,the authors have established the structure of the sensor and designed weak signal detecting circuit of the sensor based on infrared spectrum absorption principle,differential de-noising principle and weak signal detecting principle.The authors have made experiments using CH4 gas.The results show that the circuit can remove noise effectively and detect weak electrical signal obtained from the detector.

Corrosion detection of tinplate cans containing coffee using EIS/EN sensor

The corrosion behavior of tinplate cans containing coffee was investigated using novel electrochemical impedance spectroscopy(EIS) and electrochemical noise(EN) sensors.The contents of iron and tin dissolved in cans were detected by inductively coupled plasma mass spectrometer(ICP-MS),and the morphology of corroded surface was observed by optical microscopy and scanning probe microscopy(SPM).The results reveal that the coating resistance,charge transfer resistance and noise resistance decrease with the prolongation of storage time.The iron and tin contents in cans increase with the storage time,while the bump height of coating surface increases from 30 nm to 80 nm during the corrosion of twelve months.The existence of deformation would enhance the corrosion process of tinplate cans.Finally,the corrosion mechanism of tinplate cans in coffee was proposed.

Output Characteristics of Photoelectric Slip Sensor Based on Micro-vibration Detection

In order to achieve the manipulator's soft grasp function, the key is to have slip sensors with fine performance. Depending on the elastomer and photoelectric elements installed in the hand, the sensor transforms the slippage between the grasped object and the robot's hand to electric signal, thus the slippage can be detected. It will cause elastomers' micro-vibration when the object is slippage. Based on the vibration theory, dynamic theory, light intensity theory and elastic deformation theory, derived is the conclusion that the object's slippage acceleration relativing to the robot's hand has linear relationship with the photoelectric elements' output voltage's differential, and then the model for slippage distinguishing is set up.

An Experience of On-site PD Testing for Condition Monitoring of an 11 kV PILC Cable Insulation System

A cable circuit of a substation in the United Kingdom showed high level of PD activities during a survey using hand hold PD testing equipment. The authors were invited to carry out on-site PD testing experiment to further diagnose and locate the potential problem of the cable system. This paper presents the experience of the present authors carrying out the cable test. Following a brief introduction to the experiment equipments and physical connections, the paper analyses the data collected from the testing, including PD pulse shape analysis, frequency spectrum analysis and phase resolved PD pattern analysis. Associated with PD propagation direction identification, PD source diagnosis and localisation was made. Four different types of sensors, which were adapted during the testing, are shown to have different frequency bandwidths and performed differently. Aider comparing the parameters of the sensor and the PD signals detected by individual sensor, optimal PD monitoring bandwidth for cable system is suggested.

Research on Comparison of Gas Chromatography and Liquid Chromatogram Detecting Pesticide Residue

The existing methods of detecting pesticide residue include gas chromatography, high performance liquid chromatography, gas chromatograph-mass, liquid chromatograph-mass, capillary electrophoresis, radioimmunoassay, biosensor and rapid detection on the spot. The paper analyzes the comparison of gas chromatography and liquid chromatogram detecting pesticide residue, for achieving the development tendency and the future goal of analyzing pesticide residue.

Fabrication of optical fiber sensor based on double-layer SU-8 diaphragm and the partial discharge detection

In this paper, a partial discharge detection system is proposed using an optical fiber Fabry-Perot(FP) interferometric sensor, which is fabricated by photolithography. SU-8 photoresist is employed due to its low Young's modulus and potentially high sensitivity for ultrasound detection. The FP cavity is formed by coating the fiber end face with two layers of SU-8 so that the cavity can be controlled by the thickness of the middle layer of SU-8. Static pressure measurement experiments are done to estimate the sensing performance. The results show that the SU-8 based sensor has a sensitivity of 154.8 nm/kP a, which is much higher than that of silica based sensor under the same condition. Moreover, the sensor is demonstrated successfully to detect ultrasound from electrode discharge.

Fiber Laser Sensor Based on a Phase-Shifted Chirped Grating for Acoustic Sensing of Partial Discharges

Acoustic emission monitoring is often used in the diagnosis of electrical and mechanical incipient faults in the high voltage apparatus. Partial discharges are a major source of insulation failure in electric power transformers, and the differentiation from other sources of acoustic emission is of the utmost importance. This paper reports the development of a new sensor concept - a fiber laser sensor based on a phase-shifted chirped fiber grating - for the acoustic emission detection of incipient faults in oil-filled power transformers. These sensors can be placed in the inner surface of the transformer tank wall, not affecting the insulation integrity of the structure and improving fault detection and location. The performance of the sensing head is characterized and compared for different surrounding media： air, water, and oil. The results obtained indicate the feasibility of this sensing approach for the industrial development of practical solutions.

Metal chelate affinity to immobilize horseradish peroxidase on functionalized agarose/CNTs composites for the detection of catechol

The paper reports a novel amperometric biosensor for catechol based on immobilization of a highly sensitive horseradish peroxidase by affinity interactions on metal chelate-functionalized agarose/carbon nanotubes composites. Metal chelate affinity takes advantage of the affinity of Ni2＋ ions to bind strongly and reversibly to histidine or cysteine tails found on the surface of the horseradish peroxidase. Thus, enzymes with such residues in their molecules can be easily attached to functionalized aga- rose/carbon nanotubes composites support containing a nickel chelate. Linear sweep voltammograms and amperometry are used to study the proposed electrochemical biosensor. Catechol is determined by direct reduction of biocatalytically liberated quinone species at -0.05 V （vs. SCE）. The effect ofpH, applied electrode potential and the concentration of H2O2 on the sensitivity of the biosensor has been investigated. The performance of the proposed biosensor is tested using four different phenolic compounds, showing very high sensitivity, in particular, the linearity of cateehol is observed from 2.0 × 10-8 to 1.05×10-5 M with a detection limit of 5.0×10-9 M.

Ultra-low charge transfer resistance carbons by onepot hydrothermal method for glucose sensing

Hydrothermal carbon （HTC） is typically well- dispersed, but it remains a great challenge for HTC to become conductive. Co-doping with heteroatoms has been confirmed to be an effective strategy to significantly promote the electrical conductivity of carbon. Moreover, there is no simple and green method to construct sensitive HTC based electro- chemical biosensors until now. In this paper, N and S dual-doped carbon （NS-C） with ultra-low charge transfer resistance is easily synthesized from L-cysteine and glucose in a hydrothermal reaction system. The morphology, structural prop- erties and electrochemical properties of the as-prepared NS-C are analyzed. In comparison with the undoped hydrothermal （UC） modified glassy carbon electrode （GCE）, the charge transfer resistance of UC （476 Ω） is ten times the value of NS- C （46 Ω）. The developed biosensor shows a better performance to detect glucose in a wide concentration range （50-2500 μmol L^-1） with the detection limit of 1.77 μmol L^-1 （S/N-3） and a high sensitivity （0.0554 μA cm^-2μmol^-1 L）. The apparent Michaelis-Menten constant value of GCE/NS-C/GOx/nafion modified electrode is 0.769 mmol L^-1, indicating a high affinity of glucose oxidase to glucose. These results demonstrate that the hydrothermal method is an effective way for prepar- ing high electrical conductivity carbon with excellent performances in biosensor application.

A new method of rapid quality detection of vacuum insulation panels

A new method of measuring gas pressure in vacuum insulation panels(VIPs)is reported in this study,which provides a fast and efficient quality control option of production.Although there are different methods of measuring gas pressure for VIPs,connecting an internal measurement gauge to external data acquisition units is problematic.The thin high barrier film covering the panel’s core usually prevents external electrical wires or mechanical devices being connected to the inside of the VIPs.To solve this problem,a micro capacitive pressure sensor with 0 to 250 Pa detection range is developed to detect the vacuum pressure.The sensor has high linearity and a sensitivity of 10 mV/Pa.Moreover,through the communication mode study,an ultrasound communications system for VIPs is designed.It shows from operation that this system is stable and reliable,and quick for communication speed.This new method enables the quality detection of VIPs to be completed within 1 second.The minimum detectable pressure of VIPs is below 1 Pa,and the measurement error can be controlled around 5%.

A nano-functionalized real-time electrochemiluminescent biosensor for alanine transaminase assay

An electrochemiluminescent (ECL) biosensor was constructed for selective assay of alanine aminotransferase (ALT) based on the enzymatically catalyzed oxidation of pyruvate by pyruvate oxidase (PYOD). The composite of potassium ferricyanide and carbon nanotube was adopted to pre-functionalize the basal platinum electrode while the potassium ferricyanide acted as the activator of PYOD. The ALT catalyzed the reaction of L-alanine and-ketoglutarate to produce pyruvate which could be further enzymatically oxidized by PYOD to yield H2O2 to intensify the ECL of luminol. The biosensor showed rapid response for real-time measurement of ALT in the linear concentration range from 0.00475 to 350 U/L (r = 0.993) with a relatively standard deviation of 2.5% (CALT = 47.5 U/L,n = 6). The biosensor was applied to assay the ALT in rat serum with average recovery of 90.5%.