一种基于并行混沌和SFLA的风电电网无功优化模型设计

针对已有方法在解决电网无功优化时,由于系统的无功不足和电网电压的不稳定,容易过早收敛到局部最优解的缺点,设计了一种基于并行混沌和混合蛙跳算法 (Shuffle Frog Leaping Algorithm, SFLA)的电网无功优化模型。首先,建立了最小化有功网损、最大化静态电压稳定裕度和最大化无功补偿单位投资收益的多目标数学优化模型,然后,对经典的SFLA进行改进,通过引入精英协同进化机制和划分种群的方式实现并行寻优,从而增加个体的多样性和加快最优解的求取速度,在不同种群中设计不同的适应度函数和个体更新进化方法。为了使得算法的初始解分布更为均匀,引入用混沌机制来对种群进行初始化,最后,对基于并行混沌和SFLA的总体算法进行了设计和分析。在Matlab环境下进行实验,实验结果表明文中方法得到的优化结果具有电网有功损耗小、单位投资收益高和静态电压稳定裕度大的优点,具有较强的可行性和适应性。     

Depolarization properties of cirrus clouds from polarization lidar measurements over Hefei in spring

A new polarization lidar has been developed for detecting depolarization characteristics of aerosol and cirrus over Hefei (31.90°N, 117.16°E), China. The fundamental principle of polarization lidar is briefly introduced.     

展望21世纪风能的利用与发展

本介绍了国内外风能利用的现状,并对我国未来风能的利用与发展提出了很多建设性的意见,诸如：发展目标的确立,政策、法规体系的建立,技术性能的提高及新产品的开发,经济鼓励政策及其实施,产业化体系的建设等。     

Low tropospheric wind measurement with Mie Doppler Lidar

A double edge Mie Doppler lidar at 1064 nm was developed in Hefei, China in 2005 for low tropospheric wind measurement. Intercomparison experiments with a wind profiler and a wiresonde were held. Intercomparisons of concurrent lidar and other instrument observations show good agreement with expected measurement accuracy. The examples of validated lidar wind profiles obtained during these experiments as well as an example of continuous wind observations are presented. The instrument has demonstrated the capability of atmospheric wind field measurement from 0.2 to 5 km altitude, achieving below 2 m/s accuracy with 1 min averaging and 21.2 m vertical resolution.     

Nontrivial Phase Transition in a Continuum Mirror Model

We consider a Poisson point process on with intensity , and at each Poisson point we place a two sided mirror of random length and orientation. The length and orientation of a mirror is taken from a fixed distribution, and is independent of the lengths and orientations of the other mirrors. We ask if light shone from the origin will remain in a bounded region. We find that there exists a with 0 < < for which, if < , light leaving the origin in all but a countable number of directions will travel arbitrariliy far from the origin with positive probability. Also, if > , light from the origin will almost surely remain in a bounded region.     

大气消光特性与机载激光雷达眼睛安全关系的研究

依据美国ANSI标准，定量分析了气溶胶、卷云和沙尘的垂直消光特性对机载激光雷达激光脉冲眼睛安全最大阈值能量的影响；以地基激光雷达探测得到的合肥上空沙尘暴为例，定量给出了大气中各成分消光特性对飞机眼睛安全最低高度的影响；模拟计算了各种大气成分的消光特性对激光脉冲眼睛安全系数的影响随高度的变化规律。计算结果表明：沙尘层对激光脉冲眼睛安全最大阈值能量的影响幅度可达几十毫焦。该结果为我国第一台机载大气探测激光雷达激光脉冲能量设置提供了基本依据。     

条纹管激光成像系统空间分辨力实验研究

简要分析了非扫描激光成像的技术优势,介绍了利用条纹管实现非扫描激光成像的工作原理,说明了图像空间分辨力与系统距离精度的对应关系。对影响图像空间分辨力的主要因素进行了理论分析,得到了系统总空间分辨力与各单元器件空间分辨力和放大倍率的对应关系,在此基础上,对现有条纹管成像系统进行了相应的计算,得到了空间分辨力的理论预期值;最后,提出了一种基于分辨力板成像的系统空间分辨力测试方法,设计了相应的验证实验,对实测图像进行了去噪处理和数据分析,得到了图像的衬比度传递函数(CTF)曲线,通过衬比度传递函数分析,计算出了成像系统的实际空间分辨力,并将实测的分辨力数据与理论值进行了对比分析。     

变光外差为电外差的双频激光探测

演示一种双频激光位移探测系统,阐述光载波激光雷达的概念。由单块非平面环形腔固体激光器和声光调制器产生100MHz载波频率的双频激光束,作为探测光束,经过光路收发系统,探测位于电动导轨上目标的位移变化,信号处理部分采用高速光电探测器响应后信号的电子外差解调方式,位移量的获得通过高频锁相放大器解算参考光束与信号光束的相位差并计算获得。通过双频激光把光学外差探测变为了电子外差探测,系统重复误差小于3%。系统在利用无线电雷达信号处理方式的同时,保留了激光探测的优点,位移测量系统具有良好的重复性。     

大风区铁路沿线挡风墙积沙机理及优化措施的风洞实验研究

位于兰州至新疆的兰新二线是世界上首条穿越大风区的高速铁路,途径著名的烟墩风区、百里风区、三十里风区及达坂城风区,风区段铁路里程长达 462.4 km,占新疆段线路总长的 65.1${\%}$,大风对铁路的运营、养护和运输造成很大危害. 为了降低大风对通行列车的危害,兰新铁路沿线设置了大量挡风墙. 挡风墙发挥作用的同时,也带来了铁路沿线的积沙问题. 为了解决这一工程实践的现实问题,本文提出了在现有挡风墙背风侧的不同位置处,设立第二道挡墙以减弱铁路积沙的治理思路,并开展了对应条件下对现有单道挡风墙、以及在现有单道挡风墙背风侧坡顶处和坡脚处设置第二道挡墙,共计3种情景的风洞模拟实验,发现设置第二道挡墙后距轨道线路高0.1 m处的沙粒水平速度、数密度、输沙通量及沉积率较无第二道挡墙时明显减少,介于8%$\sim$12${\%}$,51%$\sim$69${\%}$,20%$\sim$73${\%}$以及26%$\sim $38${\%}$,而且在现有单道挡风墙背风侧坡顶部增设第二道挡风墙的效果更好. 因此,本文的研究成果有助于优化大风区已有铁路沿线、城镇等防沙治沙工程措施.      

Wind effects on noise propagation for complicated geographical and road configurations

Outdoor propagation from roads is influenced by wind, temperature and humidity. It is necessary to predict wind effects to simulate long-term environmental noise accurately. Noise levels have been measured in conjunction with wind speed and wind direction measurements. These noise levels showed noticeable daily changes. Excess attenuations of noise levels were found to depend on the vector wind (U_vec). By relating the vector wind and observed sound attenuations under all wind conditions, the influence of wind can be more accurately predicted for purposes of simulating noise propagation.