回归正交试验法在水轮机调节系统参数优化中的运用

提出了一种优化非线性系统控制参数的方法——回归正交试验法。该方 法运用正交试验原理安排一定的试验次数，再将试验结果用最小二乘法进行拟合，在控制参 数与目标函数间建立起回归经验公式，利用该经验公式对整个系统的动态性能进行预测和控 制。该方法已应用于水轮机调速系统控制参数的优化，仿真结果表明其优化效率高，提高了 系统的动态品质。     

参数自适应模糊PID控制器及其在水电机组调速器中的应用

由于水电机组调速系统控制对象———水轮机的运行工况在不断变化，描述水轮机动态特性的数学模型及引水系统的模型参数时刻发生变化，常规PID控制的应用受到限制。文中引入了模糊控制理论，使用参数自适应模糊PID控制器替代常规PID控制器，通过仿真结果显示，对水电机组过渡过程的控制具有明显的效果。     

中线式沟谷型尾矿库设计优化要点分析

为降低中线式尾矿筑坝法的沟谷型尾矿库运行成本,确保安全环保运行,使其设计更加优化和贴合实际,结合我国南方山区沟谷的地形地质特征,以现行规范对中线式尾矿库的规定与库区现场实际相结合的方法,明确了中线式尾矿库设计前期勘察重点所在,提出了设计前期需开展旋流器分级、尾矿堆坝、尾矿管道输送水力学等试验和设计中加强保护第四系覆盖层、优化初期尾矿排放方式为不分级入初期库及初期坝轴线适当下移、后期堆积坝轴线适当偏移的设计理念。预期效果表明,不仅可提高中线式沟谷型尾矿库设计的精细化水平,还将有利于尾矿库运行工序简化、降低成本、确保安全环保,我国南方山区的中线式尾矿库设计应不拘泥于细节、不受传统中线式尾矿筑坝法束缚,成果可供相关尾矿库设计人员参考。     

双孔圆形洞室围岩应力分析的交替法研究

利用Ｓｃｈｗａｒｚ交替法对双孔圆形洞室的围岩应力分析进行了研究。结果表明，完成二次迭代后，就可获得精度很高的满意结果。     

Variable Structure and Time-Varying Parameter Control for Hydroelectric Generating Unit

Better access and management of data can reduce operating and maintenance expenses for electric power systems. The use of an integrated data management and analysis system provides a method to easily manage the electric generating station data and links required data to analysis programs. This paper describes a software package which provides a PC based single data model environment for storing, retrieving and analyzing electrical power system data. This paper also discusses the implementation of the system for an operating nuclear power generating station. Lessons learned in integrating the system in a plant configuration management plan are described.     

A Novel Interpolation Equalization Technique for Multicarrier Modulation/Demodulation Systems

This paper presents a novel multitap interpolation equalization technique for filter bank-based multicarrier modulation/demodulation systems. The proposed technique is based on the equalization of the channel fractional delay in each subchannel in time synchronization with the constituent receiver side decimator. The proposed synchronization is achieved by combining a subset of the polyphase components of the analysis filter output signal after having passed through a bank of interpolation equalizers. The resulting multitap interpolation equalization permits a trade-off between various equalization parameters, such as the number of used polyphase components, the length of the equalizer, and the interchannel interference terms, making it possible to achieve a high signal-to-noise ratio (SNR) involving moderate equalization cost or a moderate SNR involving very low equalization cost. Simulation results for the standard carrier serving area loop show that the proposed equalization technique gives rise to 15 dB improvement in SNR compared to the output combiner equalization technique and can achieve an SNR close to the matched-filter bound for the channel by employing a reasonable equalizer length. Compared to the output combiner equalization technique, the proposed equalization technique involves around three times less the storage requirement at the same computational cost or around three times less the computational cost at the same storage requirement for equalizer training. Two suboptimal solutions are also proposed to simplify the equalizer training at only a minor loss in SNR.     

弹性位移反分析对地应力、弹模的反演唯一性

地下工程中的平面线弹性问题共有 5个被关心的参数 ,即竖直、水平及剪切地应力分量、弹模和泊松比。利用单个洞室存在时的位移解析解对位移反分析所能辨识出的参数个数作了进一步的研究 ,发现所有地应力分量和弹模同为未知量时的反演不具有唯一性 ;此外 ,无论洞室形状如何 ,都有可能唯一地反演出各种组合下的未知参数 ,但形状简单的洞室对参数的限制条件较多。     

Unraveling the Sinuous Grain Boundaries in Graphene

Grain boundaries (GBs) in graphene are stable strings of pentagon‐heptagon dislocations. The GBs have been believed to favor an alignment of dislocations, but increasing number of experiments reveal diversely sinuous GB structures whose origins have long been elusive. Based on dislocation theory and first‐principles calculations, an extensive analysis of the graphene GBs is conducted and it is revealed that the sinuous GB structures, albeit being longer than the straight forms, can be energetically optimal once the global GB line cannot bisect the tilt angle. The unusually favorable sinuous GBs can actually decompose into a series of well‐defined bisector segments that effectively relieve the in‐plane stress of edge dislocations, and the established atomic structures closely resemble recent experimental images of typical GBs. In contrast to previously used models, the sinuous GBs show improved mechanical properties and are distinguished by a sizable electronic transport gap, which may open potential applications of polycrystalline graphene in functional devices.     

含氟有机化合物的转产与降解研究进展

简要介绍含氟有机化合物的环境影响,以国内外学者的研究为依据,重点阐述了挥发性含氟有机化合物包括氯氟碳类化合物(CFCs)、氢氯氟碳类化合物(HCFCs)、氢氟碳化合物(HFCs)、含氟醚的转产及降解方法和不挥发性含氟有机化合物、氟代芳香族化合物、全氟辛烷磺酸(PFOS)和全氟辛烷羧酸(PFOA)的降解途径,并提出了将来含氟有机化合物的转产及降解的发展方向。