Design Scheme of Electric Lifting Workbench for Maintenance of Aerometer in Observation Field

The wind speed and wind direction meter of meteorological station is installed on the wind meter pole 10 meters high from the observation site, which also causes some difficulties for the maintenance of the wind speed and wind direction meter in the later period. Based on this situation, an electric lifting worktable (referred to as the electric lifting worktable) is specially designed for the maintenance of wind meters in meteorological observation sites. It can lift the maintenance personnel and equipment and tools to a height convenient for work, and then grasp the wind meter pole through the mechanical arm. It can be operated by a single person, thus getting rid of the traditional dimension by climbing the wind meter pole or releasing the wind meter pole. The present situation of repairing has the characteristics of saving manpower and easy operation, which is conducive to improving work efficiency and reducing work intensity. It also greatly guarantees the safety of maintenance personnel, and has good practicability and extensive popularization value.

Influence of alloy components on arc erosion morphology of Ag/MeO electrical contact materials

Arc erosion morphologies of Ag/MeO（10） electrical contact materials after 50000 operations under direct current of 19 V and 20 A and resistive load conditions were investigated using scanning electron microscope（SEM） and a 3D optical profiler（3DOP）. The results indicated that 3DOP could supply clearer and more detailed arc erosion morphology information. Arc erosion resistance of Ag/SnO_2（10） electrical contact material was the best and that of Ag/CuO（10） was the worst. Arc erosion morphology of Ag/MeO（10） electrical contact materials mainly included three different types. Arc erosion morphologies of Ag/ZnO（10） and Ag/SnO_2（10） electrical contact materials were mainly liquid splash and evaporation, and those of Ag/CuO（10） and Ag/CdO（10） were mainly material transfer from anode to cathode. Arc erosion morphology of Ag/SnO_2（6）In_2O_3（4） electrical contact materials included both liquid splash, evaporation and material transfer. In addition, the formation process and mechanism on arc erosion morphology of Ag/MeO（10） electrical contact materials were discussed.

Differences in body components and electrical characteristics between youth soccer players and non-athletes

Many previous studies have focused on youth soccer player injuries without body component analysis compared to non-athletes. Only a few studies which have investigated body components of youth soccer players, and studies that look at electrical characteristics used by rheobase and chronaxie as well as body components are even scarcer. Therefore, we feel that there is a need for a study investigating objective clinical analysis of the body components (body structure and body composition) and electrical characteristics of both youth soccer players and non-athletes. Sixty subjects participated in our study, comprising of thirty youth soccer players and thirty non-athletes. The Inbody 520 was used to measure and analyze body composition and the Duo 500 was employed to measure electrical characteristics. It was observed that the soccer players showed markedly lower total impedance compared to the non-athletes. In both legs, it was particularly noted that there were significant differences between the right and left sides. The soccer players showed a higher skeletal muscle mass and lean/ideal lean × 100% compared to the non-athletes. Furthermore, the soccer players had a lower rheobase and higher chronaxie. A comparison of the genders showed a similar pattern. In this study, we were able to separate the differences in body components and electrical characteristics between the subject groups using a systemic approach. Future studies on diverse types of athletes would contribute further to the development of clinical physiotherapy and sports rehabilitation.

Safety Requirements And Inspections Methods For Insulating Components Used In Electrical Accessories

This paper covers the safely requirements and inspection methods for insulating components used in electrical accessories by an analyzing the properties of the insulating components used in electrical accessories based on the standard of IEC 60884.

The influence of probe lift-up height on CNT electrical properties measurement under EFM DC mode

Nowadays,one of the bottlenecks which hinder the development and application of carbon nanotube(CNT)nano device is that no pure semiconducting CNT(s-CNT)or metallic CNT(m-CNT)can be obtained,and for solving this problem scientists proposed some methods on preparation or separation,but all the results still should be detected and feedback to the process for further improving the preparation and separation methods.Thus,it is very important to measure and distinguish the electrical properties of CNT.For that,scientists proposed a method to measure CNT electrical properties based on DC electrostatic force microscope(EFM)mode,which distinguishes m-CNT from s-CNT according to different scan line shape to CNT with different electrical properties.But,we discovered that the probe lift-up height will seriously affect the shape of the scan line,which makes this method not reliable in distinguishing m-CNT from s-CNT.In this paper,the authors deeply researched the influence of probe lift-up height and also gave corresponding theoretical analysis and explanation,which will greatly improve the method of detecting CNT electrical properties by EFM.

Electricity price forecasting using generalized regression neural network based on principal components analysis

A combined model based on principal components analysis (PCA) and generalized regression neural network (GRNN) was adopted to forecast electricity price in day-ahead electricity market. PCA was applied to mine the main influence on day-ahead price, avoiding the strong correlation between the input factors that might influence electricity price, such as the load of the forecasting hour, other history loads and prices, weather and temperature; then GRNN was employed to forecast electricity price according to the main information extracted by PCA. To prove the efficiency of the combined model, a case from PJM (Pennsylvania-New Jersey-Maryland) day-ahead electricity market was evaluated. Compared to back-propagation (BP) neural network and standard GRNN, the combined method reduces the mean absolute percentage error about 3%.

Design of Parallel Electrical Resistance Tomography System for Measuring Multiphase Flow

ERT(electrical resistance tomography) is effective method for visualization of multiphase flows,offering some advantages of rapid response and low cost,so as to explore the transient hydrodynamics.Aiming at this target,a fully programmable and reconfigurable FPGA(field programmable gate array)-based Compact PCI(peripheral component interconnect) bus linked sixteen-channel ERT system has been presented.The data acquisition system is carefully designed with function modules of signal generator module;Compact PCI transmission module and data processing module(including data sampling,filtering and demodulating).The processing module incorporates a powerful FPGA with Compact PCI bus for communication,and the measurement process management is conducted in FPGA.Image reconstruction algorithms with different speed and accuracy are also coded for this system.The system has been demonstrated in real time(1400 frames per second for 50 kHz excitation) with signal-noise-ratio above 62 dB and repeatability error below 0.7%.Static experiments have been conducted and the images manifested good resolution relative to the actual object distribution.The parallel ERT system has provided alternative experimental platform for the multiphase flow measurements by the dynamic experiments in terms of concentration and velocity.

The Electrical Conductive Effect of Nickel-coated Graphite/Two-component Silicone-rubber Sealant

Nickel-coated graphite particles and two-component silicone-rubber were compounded to form a conductive composite system. The electrical volume resistivity of the composites were examined and compared under constant tensile strains, cyclic heating-cooling, electric field and repeated cyclic tensile strains in order to study the mechanism of electrical conductivity behaviors of the conductive composites under stress, temperature and current. The results showed that a peak value of the electrical resistivity appeared previously and then gradually increasing with increasing tensile strain. The electrical resistivity displayed positive temperature coefficient effect during the temperature increasing and decreasing. Applying 5A direct current to the conductive composites lesulted in an increase in the electrical resistance immediately, but no changes were detected under lower currents. Under the repeated cyclic strain, the peak value of the electrical resistivity of each cycle increased with the test cycle. All the electrical resistivity changes were attributed to the conductive networks broken-up and rebuilt in the conductive composites.

Preventive condition-based maintenance model of EMU components based on stochastic differential equation

To improve the operation and maintenance management level of large repairable components,such as electrical equipment,large nuclear power facilities,and high-speed electric multiple unit(EMU),and increase economic benefits,preventive maintenance has been widely used in industrial enterprises in recent years.Focusing on the problems of high maintenance costs and considerable failure hazards of EMU components in operation,we establish a state preventive maintenance model based on a stochastic differential equation.Firstly,a state degradation model of the repairable components is established in consideration of the degradation of the components and external random interference.Secondly,based on topology and martingale theory,the state degradation model is analyzed,and its simplex,stopping time,and martingale properties are proven.Finally,the monitoring data of the EMU components are taken as an example,analyzed and simulated to verify the effectiveness of the model.

Study on the Lightning-radaited Electric Field Components at Mesospheric Altitudes

In this paper we have extended the semi-analytical model presented by Yashunin et al.to compute both of the lightning vertical and horizontal electric field considering the effect of nonlinear atmospheric electric parameters,and validate its accuracy by using our 2-D FDTD method.It is noted that the semi-analytical model can predict not only the lightning vertical field,but also the horizontal electric field with a satisfied accuracy in a small region with a radius ranging from 5 to 30 km at a height from 80 to 90 km above the lightning strike point.Compared with the results in the free space with a vacuum,the conducting altitude atmosphere has a relatively little effect on the radiated field component,but it has much effect on the electrostatic and induction component because their duration times are longer than the local relaxation time.For example,the induction field component in the conducting nonlinear medium decreases by about 43%,compared with that in the free space with a vacuum.The induction field is larger than the radiation field component within a radius of 25 km at a height of 80 km above the lightning strike point.Therefore,although the induction component may be likely one extra energy source(except for the radiation field)for creating the pancake shape of some elves with a luminous central part,we have to take into account the effect of nonlinear atmospheric electric parameters on the prediction of induced field component peak value that is needed for the production of elves.

基于电成像的孔洞型碳酸盐岩储层连通性评价

碳酸盐岩储层非均质性强,孔隙结构复杂,相较于常规碎屑岩储层,其孔隙度、渗透率关系的规律及特征不明显。碳酸盐岩储层的连通性与孔洞特征具有强相关性,且连通性是影响储层渗透率的重要因素,因此,对碳酸盐岩孔洞连通性的评价是孔洞型碳酸盐岩储层评价的关键问题。以伊拉克东南部B油田FQ-1井M组MB21亚油组孔洞型碳酸盐岩储层为例,基于地层微电阻率扫描成像(FMI)测井的高分辨率动态图像,利用最大类间方差算法(OTSU)进行二次迭代分割,识别电成像图像孔洞;根据8连通域标记法标记连通孔洞;提取每个连通孔洞的特征孔径、内部最长通道距离、内部最长通道与水平方向夹角、平均通道宽度这4个几何参数,最终构建孔洞型碳酸盐岩储层连通指数。连通指数在伊拉克东南部B油田FQ-1井M组MB21亚油组孔洞型碳酸盐岩储层的应用表明,利用此方法建立的连通指数与FQ-1井碳酸盐岩储层岩心渗透率相关系数达0.8437,并且连通指数曲线的趋势符合岩心渗透率在储层不同深度的分布情况,证明了连通指数可以指示储层孔隙结构较好、溶蚀孔洞发育的深度段,并可以划分储层中连通性较好的深度区间,该参数对于寻找碳酸盐岩储层渗透层具有重要意义。

基于相位差的轴向磁通无铁心电机早期轻微匝间短路故障诊断

针对轴向磁通定子无铁心电机早期匝间短路故障问题,提出一种基于零序分量和定子电流分量相位差的轴向磁通定子无铁心电机的早期匝间短路故障诊断和定位方法。首先,根据定子绕组电感极小的特点建立了匝间短路故障数学模型;其次,对故障前后的短路电流、相电流、零序分量等进行了傅里叶分析,通过零序电压基波幅值变化对匝间短路故障进行识别;最后,通过对比零序电压基波与定子三相电流初相位差来进行故障相定位。结果表明,匝间短路故障相的相电流基波初始相位与零序电压基波初相位差的绝对值近似180°,而健康相的相位差与180°相差较大。基于相位差可以实现轴向磁通无铁心电机早期匝间短路故障的诊断与定位,为永磁电机的匝间短路故障诊断提供了参考。

电气部件三维建模方法探析——以交流接触器为例

介绍数字化电气设计中电气部件常用的两种三维建模方法,详细描述基于外形尺寸的三维绘制和借助扫描仪进行三维扫描建模的具体操作流程及注意事项。通过比较两种建模方法的优缺点,供设计者在实践中选择合适的建模方法,提高设计效率和准确性。

基于电学特性识别贺兰山东麓年份葡萄酒研究

以贺兰山东麓3个年份两个品种的葡萄酒为试材,运用LCR仪测定其电学特性,分析不同激励电压(1、3、5 V)和不同频率(0.1、1.0、10.0、100.0、1000.0 kHz)下葡萄酒间电学特性的差异,筛选出识别年份葡萄酒的最适激励电压、频率和有效电学参数,探索利用电学特性识别贺兰山东麓年份葡萄酒的可行性。结果表明,在本研究中葡萄酒电学参数在不同电压下随频率的增加变化趋势一致,但不同年份间分离程度有所差异。在本研究中,随着频率的增加,葡萄酒电学参数Z值和Cp值逐渐减小,G值逐渐增加,θ值先增后减,B值则先减后增;而D值仅‘赤霞珠’葡萄酒在1 V+0.1 kHz条件下存在显著差异。通过多元统计分析,LCR仪在5 V激励电压+1.0 kHz频率条件下,能够利用Z、Cp、G、θ和B这5个电学参数来识别贺兰山东麓‘赤霞珠’和‘雷司令’年份葡萄酒。

基于电学参数的贺兰山东麓赤霞珠葡萄酒子产区判别

本研究以宁夏贺兰山东麓5个子产区(银川、青铜峡、红寺堡、石嘴山和农垦产区)自然发酵的赤霞珠干红葡萄酒为研究对象,测定其基本理化指标和电学特性,分析不同产区葡萄酒间电学特性的差异,筛选出区分不同产区葡萄酒的特征频率和有效电学参数,初步探索基于电学特性识别宁夏贺兰山东麓不同子产区葡萄酒的能力,以期为简捷快速有效识别产区葡萄酒提供新方法。结果表明,宁夏贺兰山东麓5个子产区的葡萄酒理化指标间存在显著性差异,农垦产区的葡萄酒可滴定酸含量最高,而还原糖含量最低;银川产区的葡萄酒挥发酸含量最低,石嘴山产区的葡萄酒酒精度最高。通过相关性分析、方差分析和多重比较,筛选出电压2 V下,区分不同产区葡萄酒的电学特性特征频率为0.1 kHz,有效电学参数为Z、L_(p)、X、C_(p)和Q。主成分分析和判别分析均显示,利用葡萄酒电学参数能够明显区分贺兰山东麓5个子产区,采用Fisher-判别分析建立的预测模型,其回代检测和交叉验证正确率均为100%。因此,利用葡萄酒电学特性识别产区具有可行性。

CEEMD-FastICA-CWT联合瞬态响应阶次的电驱总成噪声源识别

以某增程式电驱动总成为研究对象,提出基于联合算法的噪声分离识别模型。首先,采用互补集合经验模态分解(complementary ensemble empirical mode decomposition,CEEMD)联合快速独立分量分析(fast independent component analysis,FastICA)方法提取纯电模式稳态工况下单一通道噪声信号特征,利用复Morlet小波变换及FFT对各分量信号时频特性进行识别。其次,采用阶次分析法和声能叠加法对稳态分量信号对应的各瞬态响应阶次能量进行对比分析,并结合皮尔逊积矩相关系数(Pearson product moment correlation coefficient,PPMCC)相似性识别确定不同噪声激励源贡献度。结果表明:减速齿副啮合噪声对该增程式电驱总成纯电模式运行噪声整体贡献度最大。

基于DEMATEL-ISM的电动绳索升降机性能影响研究

为了提高电动绳索升降机性能,该文采用集成决策实验室分析法和解释结构模型法来分析影响升降机性能的各个因素以及各因素的中心度和原因度,并从中找出关键原因因素(电机选型、抓绳机构、结构材料、电池设计和攀爬类型)及关键结果因素(载重、运行距离、减速机选型、最大速度和加减速)。再对系统层次进行划分,对影响升降机性能的深层因素和根本因素进行分析,从而得出系统的深层影响因素(结构材料、电池设计、电机选型和抓绳机构)及根本影响因素(攀爬类型)。所研究结果为提升升降机性能提供思路和方向。

神东煤矿机电设备大型部件安全库存分析

为探讨煤矿机电设备大型部件安全库存的必要性以及对煤企安全生产的影响,通过调研国能神东机电设备大型部件库存的现状,给出了保障国能神东煤矿机电设备大型部件安全库存的具体措施。分析认为,开展机电设备大型部件库存统计对实现国能神东在管理上的提质降本增效有重要的作用,且在实践中应建立一套符合神东模式的机电设备大型部件安全库存储备标准,有助于为设备管理提供科学精准的参考。

某光学系统电动保护罩设计

针对某光学系统光电设备转台,本文为舱内设备所必要的作业环境和防护,设计了一种电动控制的保护罩,可防护砂石,雨水,沙尘和太阳辐射等环境条件对舱内光电设备造成的损伤。本文介绍了电动保护罩的结构组成、工作原理以及控制系统的设计,并且对电动保护罩各分系统的设计进行了详细的描述。设计的样机试验结果表明,该电动保护罩具有较好的环境防护性能,具备行车工作功能,动作全程安全可靠,具有较高的稳定性和可靠性。

环状悬挑钢结构整体提升过程中局部失效研究

以北疆明珠塔旋转餐厅提升为例,通过有限元分析软件ABAQUS构建北疆明珠塔有限元模型,利用“生死单元”技术模拟不同位置构件失效,分析不同形式的局部构件失效对提升过程中旋转餐厅受力性能的影响规律,并通过现场实测数据验证了有限元模型的可靠性。结果表明:吊点处附近构件单独失效对结构应力和位移影响较大。且构件被完全提起前,构件失效越晚,构件失效前应力越大,结构动力响应越明显;此外,不同种构件同时失效对结构的影响大于单根构件失效影响的叠加,不相连同种构件同时失效对结构的影响大于相连同种构件同时失效,且影响程度随着失效构件之间距离的增加而减小。