Surface plasmon resonance (SPR) technology plays a crucial role in kinetic analysis of molecular interactions due to the advantages of real-time, label-free, and high sensitivity. However, most SPR sensors detects the protein interactions with average value of multiple molecules. In this study, we developed a single molecule binding kinetics immunosensor based on surface plasmon resonance microscopy (SPRM). A BSA based biosensor was prepared for immobilizing single molecules and the interaction between human immunoglobulin G (IgG) and its antibodies was investigated showing good concentration response and selectivity. And the molecular height influence on imaging has been observed. Finally, the single, micro, and macroscopic molecule binding kinetics parameters (ka, kd and KD) were calculated and compared revealing higher affinity in single molecule region than the expanded region. It demonstrates the importance of single molecule kinetics, which can be applied to the study of protein heterogeneity analysis.

Defects causing electrical contact issues in high-voltage cable end seals occur frequently due to poor conductor crimping, loose connections, or solder joint failures. Inspection methods based on infrared detection technology and circuit resistance testing are important for preventing such defects. To fully understand the physical mechanisms of contact failure during the operation of high-voltage cable end seals, this study establishes a simulation model of circuit resistance using finite element analysis software. It analyzes changes in circuit resistance with different volumes of oxidation and fracture in the lead seal and conducts electro-thermal coupling simulations. The results indicate that as the oxidation and fracture volumes in the lead seal increase, the circuit resistance caused by oxidation changes at the milliohm level, making it difficult to detect with infrared technology. In contrast, resistance due to lead seal fractures can rise to the ohm level, potentially exceeding the thermal tolerance of the cable’s XLPE layer, leading to insulation damage.

The pulse current method, acoustic and ultrasonic partial discharge (PD) detection, and voiceprint PD detection are commonly used detection methods for the PD detection of power equipment. To study the characteristics of PD signals of typical discharge models based on the principles of the above three detection methods, an acoustic detection experimental system consisting of a needle-tip model and a surface model was built. Acoustic tests were carried out on needle-tip models with different curvature radii and surface discharge models with different lengths of conductive paste. The experimental results showed that acoustic and ultrasonic PD detection and voiceprint PD detection exhibited different sensitivities to the needle-tip discharge models, and the combination of acoustic and ultrasonic PD and voiceprint PD detection was more beneficial for the comprehensive detection of cable PD signals. Based on voiceprint recognition technology, this study drew FFT (Fast Fourier Transformation) diagrams of different types of PD acoustic signals and analyzed the differences in the ultrasonic signal frequency distribution. The frequency band of the voiceprint PD signal of the needle-tip discharge models was concentrated in the range 17–27 kHz, and the frequency band of the voiceprint PD signal of the conductive paste discharge models was concentrated in the range 20–25 kHz. The measurement of voiceprint PD signals in these frequency bands were strengthened when the PD of a cable was detected on-site, which provides the basis for the use of the cable model for on-site PD detection.

Acoustic array sensor device for partial discharge detection is widely used in power equipment inspection with the advantages of non-contact and precise positioning compared with partial discharge detection methods such as ultrasonic method and pulse current method. However, due to the sensitivity of the acoustic array sensor and the influence of the equipment operation site interference, the acoustic array sensor device for partial discharge type diagnosis by phase resolved partial discharge（PRPD） map might occasionally presents incorrect results, thus affecting the power equipment operation and maintenance strategy. The acoustic array sensor detection device for power equipment developed in this paper applies the array design model of equal-area multi-arm spiral with machine learning fast fourier transform clean（FFT-CLEAN） sound source localization identification algorithm to avoid the interference factors in the noise acquisition system using a single microphone and conventional beam forming algorithm, improves the spatial resolution of the acoustic array sensor device, and proposes an acoustic array sensor device based on the acoustic spectrogram. The analysis and diagnosis method of discharge type of acoustic array sensor device can effectively reduce the system misjudgment caused by factors such as the resolution of the acoustic imaging device and the time domain pulse of the digital signal, and reduce the false alarm rate of the acoustic array sensor device. The proposed method is tested by selecting power cables as the object, and its effectiveness is proved by laboratory verification and field verification.

In GIS, switch cabinet, transformer and other equipment suspected defects or in the period of power protection, need real-time status monitoring. This paper integrates partial discharge detection methods such as ultrasonic detection, UHF detection and high frequency current detection, designs a non-immersion portable partial discharge monitoring system, and puts forward the corresponding monitoring process. The effectiveness of the system has been verified by field cases. It can be widely used in tracking and monitoring of suspected defects of substation equipment and main equipment of power protection, as well as real-time perception of equipment status and development trend, which provides an important supporting basis for equipment status evaluation and maintenance decision making.

To evaluate the fire resistance of a structural member, the temperature profile in the cross section of the member needs to be obtained first. Full-scale fire tests have not been conducted on floor systems with steel-plate composite structures, termed SC floors. The traditional finite element analysis does not yield reliable temperature predictions in the steel and concrete of the SC floor under a standard fire. In this paper, the effective thermal properties of concrete in an SC floor are proposed for evaluating the transient temperature field according to the special heat transfer mechanism found by test data. The validity of these effective thermal properties is established by incorporating them into a finite element model and comparing the temperature predictions with data from fire tests. It is shown that the proposed effective thermal properties of concrete provide a good prediction of the temperature field in an SC floor under fire. The derivation process of the effective thermal properties based on the heat transfer analysis makes it possible to expand the scope of its application when the situation is similar to an SC floor.

Neutrophil chemotaxis plays a vital role in human immune system. Compared with traditional cell migration assays, the emergence of microfluidics provides a new research platform of cell chemotaxis study due to the advantages of visualization, precise control of chemical gradient, and small consumption of reagents. A series of microfluidic devices have been fabricated to study the behavior of neutrophils exposed on controlled, stable, and complex profiles of chemical concentration gradients. In addition, microfluidic technology offers a promising way to integrate the other functions, such as cell culture, separation and analysis into a single chip. Therefore, an overview of recent developments in microfluidic-based neutrophil chemotaxis studies is presented. Meanwhile, the strength and drawbacks of these devices are compared.

在局部放电智能传感器的生产阶段,为了提高智能传感器的校验效率,简化校验过程中的手动操作,设计了一套自动校验系统.系统由上位机软件、中继模块和信号发生器三部分构成,分别采用以太网或无线通信技术进行各部分之间的通信,系统具有逻辑控制、数据分析和保存、自动显示校验结果的功能,实现了一键自动化校验,极大地提高了生产效率.

The quality of edge detection is related to detection angle, scale, and threshold. There have been many algorithms to promote edge detection quality by some rules about detection angles. However these algorithm did not form rules to detect edges at an arbitrary angle, therefore they just used different number of angles and did not indicate optimized number of angles. In this paper, a novel edge detection algorithm is proposed to detect edges at arbitrary angles and optimized number of angles in the algorithm is introduced. The algorithm combines singularity detection with Gaussian wavelet transform and edge detection at arbitrary directions and contain five steps: 1) An image is divided into some pixel lines at certain angle in the range from 45 degrees to 90 degrees according to decomposition rules of this paper. 2) Singularities of pixel lines are detected and form an edge image at the certain angle. 3) Many edge images at different angles form a final edge images. 4) Detection angles in the range from 45 degrees to 90 degrees are extended to range from 0 degrees to 360 degrees. 5) Optimized number of angles for the algorithm is proposed. Then the algorithm with optimized number of angles shows better performances.

Carbonyl compounds in water sources are typical characteristic pollutants, which are important indicators in the health risk assessment of water quality. Commonly used analytical chemistry methods face issues such as complex operations, low sensitivity, and long analysis times. Here, we report a silicon microfluidic device based on click chemical surface modification that was engineered to achieve rapid, convenient and efficient capture of trace level carbonyl compounds in liquid solvent. The micro pillar arrays of the chip and microfluidic channels were designed under the basis of finite element (FEM) analysis and fabricated by the microelectromechanical systems (MEMS) technique. The surface of the micropillars was sputtered with precious metal silver and functionalized with the organic substance amino-oxy dodecane thiol (ADT) by self-assembly for capturing trace carbonyl compounds. The detection of ppb level fluorescent carbonyl compounds demonstrates that the strategy proposed in this work shows great potential for rapid water quality testing and for other samples with trace carbonyl compounds.

提出了一种SF6在线监测系统的设计方案.以CC2530无线片上系统单片机为核心,通过传感器与Zig Bee无线通信实现了环境温湿度、大气压、O2浓度和SF6浓度信息采集与传输.该系统具有经济、可靠、高效等优点,在测试实验当中达到了设计要求.

OBJECTIVE:Some skeletal muscles can be subdivided into smaller segments called muscle-tendon units (MTUs). The purpose of this paper is to propose a framework to locate the active region of the corresponding MTUs within a single skeletal muscle and to analyze the activation level varieties of different MTUs during a dynamic motion task.APPROACH:Biceps brachii and gastrocnemius were selected as targeted muscles and three dynamic motion tasks were designed and studied. Eight healthy male subjects participated in the data collection experiments, and 128-channel surface electromyographic (sEMG) signals were collected with a high-density sEMG electrode grid (a grid consists of 8 rows and 16 columns). Then the sEMG envelopes matrix was factorized into a matrix of weighting vectors and a matrix of time-varying coefficients by nonnegative matrix factorization algorithm.MAIN RESULTS:The experimental results demonstrated that the weightings vectors, which represent invariant pattern of muscle activity across all channels, could be used to estimate the location of MTUs and the time-varying coefficients could be used to depict the variation of MTUs activation level during dynamic motion task.SIGNIFICANCE:The proposed method provides one way to analyze in-depth the functional state of MTUs during dynamic tasks and thus can be employed on multiple noteworthy sEMG-based applications such as muscle force estimation, muscle fatigue research and the control of myoelectric prostheses.

Single-nanoparticle detection with cylindrical and pyramidal-shaped nanopores was systematically studied using FEM (Finite Element Modeling) method simulations and terminal currents were obtained. The effects of pore size, length and the ratio of particle and pore diameter on the blocked current were discussed. Based on the obtained results, an optimal geometric dimension of nanopore for single-nanoparticle detection is suggested.

The one-line partial discharge monitoring system was more and more widely applied into the gen-erator, however, the PD signal from system was not well understood by the public to judge the failure type and take preventive means, thus, how to analyze the PD signal was introduced.

The article applies association rule mining and fuzzy inference mechanism to pattern recognition of partial discharge (PD) in XLPE cable, uses competitive agglomeration method in section division to show its discretization quality, and finds the relation between sections to collect classifying rules by association method. Then, the paper uses the fuzzy rules into pattern recoganition. This method can effectively discover the potential rules among characteristic parameters and the defect type. So it has great reference values for pattern recognition and fault diagnosis. Aiming at several typical XLPE cable discharge data, this paper extractes the relevant statistical characteristic parameters, classifies the defects by this method and makes a contrast analysis with the results from neutral network and C4.5 methods. Experimental results demonstrate the verification algorithm effective, furthermore, this technique has the advantage of better interpretation, time saving and dynamic interval, which makes it a new solution available for the pattern recognition of PD.

为了对 GIS 不同绝缘缺陷局放超高频(Ultra High Frequency,UHF)信号与视在放电量(pC)之间的对应关系,即 UHF 信号标定技术进行研究,在 GIS 内模拟了四种典型缺陷模型,选取300~400 MHz、700~800 MHz、1.4~1.5 GHz 以及0.3~3 GHz 等四种检测频段,对不同缺陷 UHF 信号标定进行研究,并采用多种数学回归模型和拟合优度校验指标对标定结果分别进行回归分析和拟合优度校验分析.研究发现,同一类型缺陷在不同检测频段上 UHF 信号幅值(mV)与视在放电量(pC)之间存在较为明显的对应关系,不同频段间对应关系存在差异,可以近似采用一元线性多项式回归模型对不同类型缺陷 UHF 信号幅值进行放电量标定.

To suppress the stochastic pulse interference in XLPE Cables,this paper uses equivalent time-frequency method to extract pulse feature values,adaptive fuzzy clustering to classify pulses,phase concentration as an index to distinguish PD(partial dischange)and stochastic pulses.Analysis results of on-site data show that this method can effectively suppress stochastic pulse interference in the PD signal,providing a useful theoretical and practical basis to assess the state of XLPE cable insulation.

A 10kV cross-linked polyethylene (XLPE) cable joint simulation model was established, in which the electromagnetic wave resulted from partial discharge (PD) was simulated by Finite Integration Technique (FIT). Factors influencing the electric field intensity and energy loss of UHF signals were analyzed. The simulation results indicate that quasi-TEM is the main propagation mode of EM wave, UHF signal intensity is related with the detection distance and the original PD pulse waveform.

In the contribution, some preliminary work on insulation subway cable was reported. Accordingly, the paper mainly deals with two problems, focusing on denoising algorithms, associated with various outside interferences existing in the field, and feature extraction method, regarding the evaluation and diagnosis results. Three distinctive categories of interferences were classified, 4 time interval based discharge diagrams were formed, 22 statistical operators were calculated out and further fingerprint of DC discharge was constructed.