Study on maximum power point tracking of photovoltaic array in irregular shadow

Traditional maximum power point tracking (MPPT) methods can hardly find global maximum power point (MPP) because output characteristics curve of photovoltaic (PV) array may have multi local maximum power points in irregular shadow, and thus easily fall into the local maximum power point. To address this drawback, Considering that sliding mode variable structure (SMVS) control strategy have such advantages as simple structure, fast response and strong robustness, and P&O method have the advantages of simple principle and convenient implementation, so a new algorithm combining SMVS control method and P&O method is proposed, besides, PI controller is applied to reduce system chattering caused by switching sliding surface. It is applied to MPPT control of PV array in irregular shadow to solve the problem of multi-peak optimization in partial shadow. In order to verity the rationality of the proposed algorithm, the experimental circuit is built, which achieves MPPT control by means of the proposed algorithm and P&O method. The experimental results show that compared with the traditional P&O algorithm, the proposed algorithm can fast track the global MPP, tracking speed increases by 60% and the relative error decreased by 20%. Moreover, the system becomes more stable near the MPP, the fluctuations of output power is greatly reduced, and thus make full use of solar energy.     

新安江电站进水口快速闸门动水闭门鉴定试验

本文叙述了应用现代科学方法和实验原型观测技术对新安江水电站进水口快速闸门进行安全检测鉴定，并介绍了水电站快速闸门动水闭门试验程序，对水电站快速闸门试验及相关鉴定有重要参考意义。     

Characteristic Features of the Optimal Processing of the Results of Measurements in the Case of a Random Observation Function

An analysis is made of the characteristic features and problems of the optimal processing of the results of measurements in the case of a random observation function utilizing a nonlinear Kalman filter. A method is proposed for increasing the convergence domain of the filter with additional processing of measurements in the frequency domain.     

基于对地观测激光回波特征的目标特性研究

本文研究了对地观测激光回波特征与地面目标特征之间的关系模型，分析了分类地面目标的激光回波特征，提出一种基于查表法的目标特性计算方法并给出了仿真结果。     

对素描教学现状的思考

要培养学生的创造力，教师主要起引导作用。应提倡感性的观察方法与理性的表现相结合。从构图阶段开始就应该贯穿创新意念，鼓励学生采用大胆新奇的构图，以独特的视觉去观察对象、设计函面，充分发挥学生的主观能动性。     

混凝土渠道糙率原型观测

糙率是渠道水力设计的关键技术参数之一，其值的准确选取决于已建工程原型观测成果的类比。选择3条不同衬砌特性的混凝土渠道进行糙率原型观测，对观测方法及步骤做了较详细描述；计算出了3条渠道的糙率，对其存在误差进行了分析探讨，可为今后进一步开展相关课题研究积累经验并供同行参考。     

小浪底水利枢纽的初期运行

总结了小浪底水利枢纽投运初期的水沙情况、孔板洞原型观测试验、调水调沙试验和枢纽的安全监测情况,介绍了大坝防渗、转轮裂纹问题的处理方案,总结了枢纽在防洪、防凌、减淤、供水和发电等方面发挥的作用。试验和对监测资料的分析表明,枢纽运行稳定,孔板洞设计合理、消能效果显著,各部位建筑物性态稳定,发挥了巨大的综合效益。     

大朝山水电站地下洞室安全监测资料分析

大朝山水电站引水发电系统为地下工程，根据各项安全监测物理量的主要观测成果，对最大观测值分析其对工程的安全影响，为保证其安全运行具有重要意义。为此，分别对大朝山水电站的主要地下建筑物，包括压力引水隧洞、地下厂房、尾水调压室的最大观测值进行了分析研究，并提出了一些建议，有较大的参考价值。     

红外化学遥感数字信号处理算法的研究进展

介绍了几种为远距离红外蒸汽信号监测开发的分类器设计，频域数字滤波，时域数字滤波等数字信号处理技术。对线性分类器，分段线性分类器和神经网络分类器等在红外化学遥感系统中的应用做了初步的探讨。对背景扣除技术，频域数字滤波技术，数字滤波的切趾方法等做了简要的描述。阐述了时域滤波技术的基本原理及实际应用。展望了红外化学遥感数字信号处理算法的研究前景。     

Comments on the shortcomings of predicting the precision of Cavalieri volume estimates based upon assumed measurement functions

It is well known that the estimation of an object's volume by means of serial cross-sections, the so-called Cavalieri method, yields an unbiased estimate. But by itself it provides no means by which to estimate how precise this estimate is unless the shape of the volume is fully known beforehand. This knowledge can only be partially determined from the serial section information that is collected. Methods have been developed that claim to surmount this difficulty by using the serial section data to create a mathematical model of the volume's shape properties. The model then is used to estimate (predict) the precision of the volume estimate (its CE) from the single set of data available. Unfortunately, the theory underlying the model is flawed and so the model itself amounts to no more than an unsubstantiated guess about the shape of the volume. Therefore, the precision of the volume estimates that one obtains from the method is only as good as the model and this cannot be ascertained from the single set of acquired data. In this letter I explain the inadequacies of the modelling method. I suggest that it be used only with caution, if at all. Instead I suggest two alternative ways to predict the CE, one that is based upon a rule-of-thumb approach to the object's shape, and another that is based upon spectral analysis of the measurement function and that is easy to implement with available computer software.