On-line Chatter Detection Using an Improved Support Vector Machine

On-line chatter detection can avoid unstable cutting through monitoring the machining process.In order to identify chatter in a timely manner,an improved Support Vector Machine(SVM)is developed in this paper,based on extracted features.In the SVM model,the penalty factor(e)and the core parameter(g)have important influence on the classification,more than from Kernel Functions(KFs).Hence,first the classification results are conducted using different KFs.Then two methods are presented for exploring the best parameters.The chatter identification results show that the Genetic Algorithm(GA)approach is more suitable for deciding the parameters than the Grid Explore(GE)approach.

On-Line Detection of EDM Spark Locations Using Potential Difference Method

The valuation relation of potential difference with discharging time in Electrical Discharge Machining (EDM) is analyzed theoretically and tested and verified by experiments designed in this paper and the relation between potential difference and spark location is induced and analyzed, and proceed by experiments under the condition of onedimension.

Integrated On-line Instrumentation System of Magnetic Properties Measurement

A portable microcomputer-controlled inspection system has been developed for detection of magnetic properties of soft magnetic materials. It incorporates custom designed software for control of the magnetic field during operation such as demagnetization, field sweeping, and for data logging and analysis. Results are recorded using a 12-bit analog to digital converter and are then stored on disk. The magnetic hysteresis loop and Barkhausen noise data can be converted into important magnetic parameters: coecivity, remanence, and hysteresis loss, Barkhausen amplitude, and Barkhausen noise energy. This system incorporated with the magnetostriction, and magnetoacoustic emission, is then related with the nondestructive detection of material degradation.

PRECONCENTRATION OF TRACE ZINC IN SEAWATER ON CPPI RESIN BY FIA AND ON-LINE DETECTION BY ICP-AFS

A quite new type of chelating resin Carboxymethylated Polyethylenimine-Polymethylenepolyphenylene Isocyanate(CPPI)is used for the preconcentration of Zn from high salt water such as seawater. The preconcentration is controlled through the technique of Flow Injection Analysis(FIA).The concentrated sample solution is then directly transferred to an Inductively Coupled Plasma-Atomic Fluorescence Spectrometer(ICP-AFS)for determination.The detection limit of Zn by the technique is about 0.06 ppb.

Microfluidic Analytical System with On-Line Luminol Chemiluminescence Detection Based on Annular Flow of Phase Separation Multiphase Flow

Microfluidic analytical system was developed based on annular flow of phase separation multiphase flow with a ternary water-hydrophilic/hydrophobic organic solvent solution. The analytical system was combined with on-line luminol chemiluminescence detection for catechin analysis. The water (10 mM phosphate buffer, pH 7.3)-acetonitrile-ethyl acetate mixed solution (3:8:4, volume ratio) containing 60 μM luminol and 2 mM hydrogen peroxide as a carrier was fed into the capillary tube (open-tubular fused-silica, 75 μm inner diameter, 110 cm effective length) at a flow rate of 1.0 μL·min-1. The carrier solution showed stable chemiluminescence as a baseline on the flow chart. Eight catechins were detected as negative peaks for their antioxidant potential with different detection times. The system was applied to analyze the amounts of catechin in commercially available green tea beverages.

Flow-Injection Microcolumn on-Line Preconcentration for theDetermination of Chromium(Ⅵ)

A rapid and sensitive on-line preconcentration method for spectrophotometric determination of chromium (VI) in nature water is described. Preconcentration and determination are based on (i) the quantitative and fast adsorption of chromium (VI) on the high surface area nanometer-size TiO2 (anatase) powders, which prepared by a sol-gel method from hydrolysis of TiCI4 and (ii) the quantitative and reproducible elution of Cr (VI) by 2. 0 mol. L-1 HCI. A mini-column system for preconcentration is developed, Cr(VI)on the mini-column is eluted and merged with a stream water and DPCB (1, 5-diphenylcarbazide ) as the chromogenic reagent. The Proposed system permits throughputs of 6 sample h--l (0. 001 μg mL-1 Cr(VI) ) or 20 sample h-1 (0. 1 μg mL-1Cr (VI) . The preconcentration factor is 55. The detection limit is 0. 8 ng·mL-1 Cr(VI). The reproducibility is satisfactory with a relative standard deviation of less than 3. 35% (0. Of μg'mL-1Cr (VI), n = 5).

The potential of FAST in detecting celestial hydroxyl masers and related science topics

The Five-hundred-meter Aperture Spherical radio Telescope(FAST) will make contributions to studies of Galactic and extragalactic masers. This telescope, with construction finished and now undergoing commissioning, has an innovative design that leads to the highest sensitivity of any single dish radio telescope in the world. FAST's potential for OH megamaser research is discussed, including the sky density of masers detectable in surveys. The scientific impact expected from FAST maser studies is also discussed.

On-line coupling of derivatization with pre-concentration to determine trace levels of methotrexate

A new simple, sensitive and precise green analytical procedure using an automated packed-reactor derivatization technique coupled with on-line solid-phase enrichment （SPEn） has been developed and evaluated to determine trace levels of methotrexate （MTX）. The method was based on injection of MTX into a flowing stream of phosphate buffer （0.04 M, ptt 3.4）, carried through the packed oxidant reactor of Cerium （IV） trihydroxyhydroperoxide for oxidative cleavage of the drug into highly fluorescent product, 2,4-diaminopteridine- 6-carboxylic acid, followed by SPEn on a head of short ODS column （10mm x 4.6 mm i.d., 5 I＋tm particle size）. The flow rate was 0.25 mL/min and packed reactor temperaturc was 40 ~C. The trapped product was back-flush eluted from the ODS column to the detector by column-switching with an environmentally friendly mobile phase consisting of ethanol and phosphate buffer （0.04 M, pH 3.4） in the ratio of 5：95 （v/v）. The eluent was monitored at emission and excitation wavelengths of 460 and was linear over the concentration range of 1.25-50 360 nm, respectively. The calibration curve ng/mL with a detection limit of 0.08 ug/ml..The method was successfully applied to determine MTX in pharmaceutical formulations with mean percentage recovery ranging from 99.48 to 99.60.

Study on Vibration Detection System of Wind-driven Generator based on Virtual Instrument

This study analyzes the structural characteristics of wind-driven generator,concludes its comment malfunctions and proposes effective methods by general fault analysis methods,so as to design online detection and fault diagnosis system of wind-driven generator in virtual instrument.This work will realize real-time detection,help engineers to proceed remote fault diagnosis,reduce maintenance time and increase production efficiency.This study is meaningful and practical to develop a fault diagnosis system for wind-driven generators,which shows professionalization of fault diagnosis system.

Analysis and Design of Surgical Instrument Localization Algorithm

With the help of surgical navigation system,doctors can operate on patients more intuitively and accurately.The positioning accuracy and real-time performance of surgical instruments are very important to the whole system.In this paper,we analyze and design the detection algorithm of surgical instrument location mark,and estimate the posture of surgical instrument.In addition,we optimized the pose by remapping.Finally,the algorithm of location mark detection proposed in this paper and the posture analysis data of surgical instruments are verified and analyzed through experiments.The final result shows a high accuracy.

基于轻量级YOLO-v4模型的变电站数字仪表检测识别

为了在变电站实际场景中准确获取数字仪表读数,智能管控变电站的安全风险,同时推动变电站智能化发展,以实际场景中变电站数字仪表作为研究对象,综合考虑实时性及准确度等,提出一种基于轻量级YOLOv4模型的变电站数字仪表检测识别方法.首先,通过从鄂尔多斯变电站实际拍摄变电站数字仪表图像数据,使用Albumentations框架对数字仪表图像进行数据扩充,构建变电站数字仪表目标检测数据集;然后,以YOLO-v4网络为基础,结合注意力机制构建一个有效通道注意(efficient channel attention,ECA)改进的深度可分离卷积模块(ECA-bneck-m);最后,提出一个轻量级YOLO-v4模型,进行模型大小与性能的对比实验.实验结果表明:本文方法可以在几乎不损失检测准确度的情况下,将整个模型存储大小压缩为原先的1/5,同时将模型推理速度从24.0帧/s提升至36.9帧/s,其实时性能够满足实际变电站检测识别的工程需要.

应用模糊PID自修正的电镀槽液温度控制方法

电镀槽液温度自动控制过程属于典型的混沌过程,在温度采集的过程中存在明显的非线性波动。典型的比例-积分-微分(PID)控制算法在这种混沌特性与非线性特性干扰下,存在控制精度较低、稳定性和鲁棒性较差等问题。此外,为解决非线性问题,PID算法需要循环迭代计算,存在控制时滞问题。以模糊控制为基础,提出了基于模糊PID的电镀槽液温度自动控制方法。该方法先设计温度数据采集结构,并将移动平均滤波、温度修正算法引入到采用的数据采集结构中,完成电镀槽液的实时温度数据采集。然后将采集到的温度数据作为构建的模糊PID控制器的输入。利用模糊控制规则引入修正因子,实现电镀槽液温度的自动控制。考虑到电镀槽液的时滞特性,在控制器中加入粗糙预估参考模型,对该特性加以抑制,提升控制性能。最后应用实验证明了所提方法的先进性。实验结果表明:所提方法具有较高的控制精度和效率,能够有效降低超调量和波动,应用效果较好。

基于ID-YOLO的数字仪表检测方法

当前针对数字式仪表检测算法在边缘设备具有实时性差、泛化性差的问题,对此提出一种采用ID-YOLO(instrument detection-you only look once)模型的变电站数字仪表检测识别方法。所提算法以YOLOv5模型为基础,首先设计轻量骨干网络(light weight-YOLO, LW-YOLO)提取图像特征,降低网络参数,提高检测实时性;然后设计了一种双级路由注意力模块(bi-level routing attention moudle, BRAM),提高网络对小数点的检测精度以及网络的鲁棒性和泛化性;最后,引入损失函数α-IoU,通过设定不同的可调节参数α数值得到更准确的真实框与预测框的交并比计算,可以提高模型的检测精度。结果表明:相比于其他基于深度学习的数字仪表检测识别方法,所提方法在不同显示方式的数字仪表识别任务上具有更好的准确性和泛化性,而且可以在检测准确率领先的情况下,将模型在边缘设备上的检测速度从6.87帧/s提升至8.77帧/s,其实时性和检测精度均能够满足实际变电站智能数据采集、检测识别的工程需要。

智能仪表预测性维护关键技术

智能仪表是大型工业过程和复杂装备系统传感与控制的“神经”,其健康状态直接影响系统的安全可靠运行。传统的智能仪表通常作为测量工具监测工艺过程和重点装备的运行状态,本体故障的忽视极易导致采集数据不准确、不可靠,影响工业过程管控效率,也易导致操作人员误判,从而引发安全事故。文中通过对智能仪表预测性维护的技术架构进行解析,建立了机理分析、数据采集、特征分析、故障自检、异常检测、故障诊断和寿命预测的技术路线,同时,从复杂工业过程视角将智能仪表分解为“传输”、“传感”和“传递”,总结了仪表本体级和系统级预测性维护的关键技术,分析了智能运维、安全仪表风险管控、信息安全风险管控3种典型应用场景,推演了诊断自组态和云边协同架构的技术发展趋势。研究可为智能仪表及系统运维由离线向在线、由预防性维护向预测性维护的转变奠定基础。

全自动检测系统在医用硬式内窥镜检测中的应用研究

目的评价使用全自动硬式内窥镜检测系统对硬式内窥镜光学性能检测的优势,并分析影响硬式内窥镜功能减退的潜在因素。方法选取某三级甲等综合医院2023年5—7月处理的硬式内窥镜镜头78条、导光束161条为研究对象,先后采用目测法和仪器检测法对其进行检测。仪器检测指标包括视向角、视场角、照度、景深、导光率、对焦、内窥镜内部密封性及纯净度;导光束指标包括光纤照度、导光率及色彩测试,比较2种检测方法的结果差异。结果目测法与仪器检测法检测硬式内窥镜镜头的合格率分别为94.87%和73.08%,差异有统计学意义(P<0.05);导光束的合格率分别为98.75%和96.89%,差异无统计学意义(P>0.05);仪器检测结果显示硬式内窥镜镜头的功能障碍主要集中在导光率和照度两方面。结论针对内窥镜镜头检测,仪器检测法明显优于目测法;针对导光束检测,两种检测方法未有显著差异。硬式内窥镜检测系统有助于及早发现硬式内窥镜镜头内部的结构变化和功能减退情况,是一种有助于降低内镜侵入诊疗操作风险、节约医院运营成本的科学检测工具。

基于FPGA和LabVIEW的磁声发射应力检测系统设计

磁声发射(Magnetoacoustic emission,MAE)是一种应力检测的有效方法,针对传统检测仪器设计参数固定,灵活性较差的问题,结合FPGA(现场可编辑逻辑门阵列)和LabVIEW设计了参数可调的磁声发射应力检测系统。其中,FPGA负责激励信号产生波形,并将接收到的AD转换数据发送至上位机进行处理。设计的LabVIEW上位机程序负责信号接收、数据处理和存储。试验结果表明,所设计的检测系统简单可靠,集成度高,能够灵活调整激励信号,满足应力检测的需求。

基于对抗学习的指针仪表自适应读数识别算法

针对指针仪表采用人工读数方式存在的成本较高、读数不准确、时效性较差的问题,提出一种基于对抗学习的指针仪表位姿自适应读数识别算法。该算法通过目标检测模型识别图像中的指针仪表的位置和姿态,将指针仪表进行校准后并利用数字图像处理技术进行读数识别。为了提升目标检测模型对位姿不同的指针仪表图像的识别效果,本文提出了基于对抗学习的数据增强技术,通过优化搜索模型识别不准的图像旋转角度、平移距离以及缩放比例构造训练数据,提高目标检测模型在指针仪表位姿发生变化时的准确率。以工矿企业中常用的SF6压力仪表为实验对象,实验结果表明读数识别的误差在1%以内,证明了所提算法的有效性。

中空纤维膜结构的电化学检测装置设计

目前中空纤维膜的结构检测手段主要包括扫描电子显微镜(SEM)、原子力显微镜等,存在检测成本高、操作不便等问题。为此,基于电化学交流阻抗谱(EIS)检测方法自主设计并开发了中空纤维膜EIS检测系统。首先,制备中空纤维膜并通过扫描电子显微镜对其进行表征;然后,针对膜结构设计检测装置,进行不同电极材质的可行性分析、不同电极长度的影响分析以及不同结构中空纤维膜的EIS检测;最后,验证了该中空纤维膜电化学检测装置的有效性。

川西北含硫气井分离器液位控制方式优化及仪表选型研究

川西北高压含硫气井投产以来,各采气单井分离器液位调节阀全部采用两位式控制方式,投产初期运行正常,但随后逐渐出现调节阀磨损、阀杆连接件卡阻、卡死不动作等故障。为解决上述问题,从液位检测仪表、分离器调节阀、液位控制方式三个维度开展应用效果对比和适应性分析,总结出一套高压含硫气井分离器液位控制推荐做法。并将研究结果在相似高压含硫气井推广应用,效果良好。这为各类分离器液位调节找到了一个新的解决思路,可为类似装置的方案设计提供参考。