光伏面板积灰及除尘清洁技术研究综述

针对光伏面板积灰、影响因素、积灰对面板转换效率的降低效应等问题,综述分析了国内外相关研究成果,总结提出了今后研究的主要方向.介绍了灰尘的来源及组成,着重综述了国内外关于光伏面板积灰形成过程及积灰引起的面板输出效率降低或太阳辐射透过率降低等研究文献,分析了面板倾角、风速风向、灰尘性质、环境湿度等主要因素对光伏面板积灰的形成和面板效率/太阳辐射透过率的影响.总结了基于灰尘性质、降尘、降雨等因素建立的积灰模型及其对面板效率的影响模型.介绍了目前常用的光伏面板清洁技术:电帘除尘和机械除尘.最后,总结了目前研究中存在的不足,并指出了今后应进一步加强积灰实验完整性、灰尘特性、积灰沉积机理、面板除尘清洁技术等方向的研究.     

开放空间内喷雾除尘效率的量化模型研究

为了提高开放空间内喷雾除尘的除尘效率,在对喷雾除尘的原理及性能进行了解,且考察了一系列影响除尘效率的因素后,如:灰尘颗粒大小、喷雾液滴的大小、喷雾的范围以及外界环境中进入系统的风速风向等,基于喷雾水滴和灰尘颗粒的力学分析和质量守恒定律,提出了除尘系统的量化模型。实验结果表明该模型能较好地反映开放空间内喷雾除尘的除尘效率,该量化模型能很好的为在开放空间内喷雾除尘效率的提高提供一个参考的方向。     

电袋复合式除尘器控制系统的设计与应用

针对电除尘技术与袋式除尘技术所面临的现实挑战,提出了电袋复合式除尘技术的应对措施,对该技术的特点作了简要描述.根据电袋复合式除尘器的特点,开发设计出其专用的控制系统.对电袋控制系统的基本原理进行了详细介绍,对于控制系统需要特殊开发设计的袋区清灰系统、保护连锁系统、人机界面系统等部分的控制策略实现方法作了重点阐述,对于控制系统的方案设计进行了介绍与探讨.实际应用表明,控制系统运行稳定可靠,具有容错功能,可满足管控一体化透明工厂目的,达到了设计要求,实现了电袋复合式除尘器的自动化运行,降低了烟气中的粉尘含量,有效提高了除尘效率.     

太阳能电池板跟踪与除尘装置的设计

太阳能电池板接收光的角度和表面对光的透过率直接影响光-电转化率。随着使用时间的积累,电池板迎光面会逐渐的积累一层灰尘主要是无机物SIO2)和有机污染物(鸟粪等),既减弱了太阳能电池板对光的吸收,影响电池的发电量,也容易因"热岛效应"造成电池局部发热而损坏。综合比较实现追踪太阳的定时法、坐标法、光敏电阻光强比较等方法,以及自然雨水冲刷、人工擦拭(高空危险)、高压水枪清洁(浪费水资源)、定时电动自动清洗(结构复杂)等电池板除尘方法,我们设计了基于单片机电池板"定点定角度"的单轴自动跟踪系统。通过对地球绕太阳运行规律、纳米TiO2超亲水性和催化降解特性的讨论,进行了"跟踪装置"和"气体喷射装置"的结构设计;电池板表面涂覆纳米TiO2实现电池板的主动自洁,基于单片机实现电池板的高压风力被动除尘和"定点定角度"的单轴自动跟踪,提高了电池板的采光效率和光透过率,进而提高其光-电转化效率。     

电袋复合除尘器技术进展及应用研究

介绍了电袋复合除尘技术的发展过程,主要对电袋复合除尘器结构、气流分布、清灰以及滤袋等方面的技术进步进行了叙述,并通过工程案例验证了电袋既可在电力行业达到超净排放的要求,未来在非电行业也会被广泛应用。     

基于SoPC的行波介电电泳芯片控制与采集平台设计

介绍了一种利用SoPC技术控制与采集行波介电电泳芯片的方案.以嵌入在FPGA(CyelonⅡ EP2C35)中的RISC结构的CPU软核NiosⅡ为基础,通过FPGA的DSP开发工具DSP Builder对直接数字频率合成器(DDS)进行建模,在QuartusⅡ软件中生成DDS IP核,控制输出4路相位严格相差90°的正弦波,建立行波电场驱动不带电生物粒子定向移动,实现不同生物粒子的分离;采用自定制I2C模块,实现300万像素CMOS图像传感器MT9T001的配置,完成不带电生物粒子的非接触检测.文中重点介绍了基于DSP Builder的DDS IP核设计,自定制I2C模块以及系统软、硬件设计,并通过仿真分析证明了这种设计方法的正确性和实用性.     

空转工况风力发电机组叶片失速振荡研究

在风力发电机组吊装完成和高风速切出或故障切出时,机组保持在空转停机状态。在现场特定风况和特定机组状态组合下,叶片容易发生由动态失速导致的振荡现象,极大威胁叶片疲劳寿命和机组安全性。根据IEC 61400-1规范中的要求,机组处于空转停机状态,应考虑极端风速模型（EWM）。针对叶片长度分别为92、97、112 m 3款叶片进行建模分析,研究机组发生失速振荡的内在规律和抑制手段。通过对机组在0～360°风向、场址极端风速以及降低风况条件进行Bladed仿真,发现3款机组均在1只叶片竖直向下位置附近、风向30°和330°附近容易发生叶片失速振荡现象。基于失速振荡发生较为集中的工况,通过调整桨距角能够实现对振荡幅值的抑制;针对不同气动外形,抑制效果有一定差别。     

风力发电机组变桨系统的设计

为了解决风力发电机组在复杂多变的风况下,能够基本保持其发电机稳定运转的问题,将PLC、变频器技术应用到风力发电机的变桨系统中。开展了变桨系统自动控制的分析,建立了PLC、变频器和变桨电机之间的关系,利用PLC及PLC的模拟量输入模块对风电场自然风风速以及风力发电机组3片桨叶的桨距角度进行了数据信息的采集,并自动进行了内部数据的处理;然后再通过对变频器的输出控制进而控制变桨电机的工作状态,使3片桨叶旋转到与自然风风速相对应的桨距角度。在发电机能自动保持稳定运转的基础上,对其性能进行了评价。分析和验证结果表明,该系统实现了对风力发电机组变桨系统的自动控制。     

基于肌电与肌动同步解析的肌肉痉挛评测方法

肌肉痉挛是常见的运动功能障碍疾病,通过肌电与肌动双模信息同步解析进行肌肉痉挛定量评估具有重要意义。本文针对同步获取高信噪比肌电与肌动信号的难点,提出一种抗工频干扰、轻量加速度计信号校正的肌电与肌动双模信息同步解析方法,设计了无线多通道肌电和肌动信号同步采集系统。与常见科学仪器Delsys系统对比,所提系统肌电信噪性能与Delsys相似(均20 d B左右),肌动信号有效频带(0～20 Hz)能量显著高于Delsys;对所提系统进行临床测试,健康志愿者主动屈肘时屈肌肌电信噪比约20 d B; 3名改良Ashworth评分(MAS)分别为1级,1+级与2级患者归一化肌电指标分别为0. 54±0. 05,0. 59±0. 04和0. 62±0. 01,屈肌肌动信号均方根值分别为2. 69±1. 04 m·s-2,3. 19±1. 13 m·s-2,4. 89±1. 19 m·s-2,肌电与肌动信息均可有效区分患者痉挛等级。因此所提方法可用于肌肉痉挛评测及肢体运动功能监测。     

电磁悬浮静电驱动旋转微镜控制系统设计

为了实现对电磁悬浮微镜绕轴向-180°到+180°角度的旋转控制.对该系统所采用的电磁悬浮、静电驱动、转角闭环控制等进行研究。首先,设计和制造了电磁悬浮微镜的定子和转子结构。接着,对通过线圈的电流频率、电流大小与悬浮高度的关系进行仿真和实验,实验结果和仿真结果基本一致。然后,在分析变电容驱动原理的基础上,进行旋转控制实验,说明在按相序通电情况下,转子能实现旋转。最后,介绍了采用高精度的电容检测的转角闭环控制系统。实验结果表明:在激励电流峰-峰值是0.5A,激励频率为20MHz时,转子悬浮到100μm高度,能够实现指定角度的控制,基本满足电磁悬浮微镜的控制要求。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....