瑞利波分析方法及应用进展

介绍了瑞利波平面及轴对称分析方法，这两种方法对数值模拟场地信号、实测频散曲线及研究各阶振型瑞利波频散曲线十分重要。用二维傅里叶变换或多次滤波，在一定程度上可将信号中瑞利波不同振型分离，得到不同振型频散曲线，而用相位差或互相关分析方法得到的频散曲线可认为是各阶振型瑞利波频散曲线加权平均．瑞利波频散曲线与半无限体分层介质力学参数有关，通过对频散曲线正、反分析可得到各层介质力学参教．此外，还介绍了瑞利波在地下目的物探测中的应用。     

Rapid Determination of Free Amino Acids,Nucleosides, and Nucleobases in Commercial Clam Species Harvested at Different Seasons in Jiangsu,China, Using UFLC-MS/MS

In this study, a sensitive and rapid method for the simultaneous quantification of 17 nucleosides and nucleobases and 23 free amino acids in clam samples using ultra-fast liquid chromatography coupled with tandem mass spectrometry (UFLC-MS/MS) was developed. Sufficient separation of 40 analytes was achieved on an Acquity BEH Amide column (2.1 mm?×?100 mm, 1.7 μm) in a single run of 15 min. The overall limits of detection (LODs) and limits of quantification (LOQs) were between 0.05~38.8 and 0.15~128 ng/mL for the 40 analytes, respectively. The newly developed method was validated and subsequently applied for the analysis of the content variation of 40 analytes in four commercial clam species (Mactra veneriformis, Ruditapes philippinarum, Meretrix meretrix, and Cyclina sinensis) collected monthly from January to December 2014 at the coast of Jiangsu, China. Significant seasonal variation was observed for most analytes. Major nucleosides and nucleobases were at their highest contents in June or July, the contents of free amino acids showed the same pattern. Thus, if high concentrations of these functional small molecules are desired, Jiangsu native clams should be harvested in early summer. The results suggest that the present UFLC-MS/MS method could be employed as a useful tool for quality assessment of the clam samples as well as other food samples using nucleobases, nucleosides, and free amino acids as markers.     

基于互联网大数据的重大场景通信保障

各类经济、文化、体育交流活动日益频繁,通信保障工作逐步常态化,研究了通过互联网大数据技术实现重大场景的通信保障,实时监测人群聚集情况、迁徙情况和感知效果,为管理者、监控及一线维护人员提供可视可控的标准化场景保障手段。根据不同场景下客户感知差异化需求和网络管理要求,建立了集多专业资源、告警、性能为一体的管理模型,突出不同应用场景下的网络特点,提升了重点区域、重点业务的实时监测,提升高效保障能力。     

雷电流作用下铁件剩磁量的规律分析

剩磁法是一种雷灾鉴定中判定是否发生雷击事故的方法,但标准中只给出判定的参考剩磁数据,其数据通用性有待斟酌。为了探究铁件剩磁量的规律,通过模拟雷电流的发生,选取一定的试样进行冲击测试后测量剩磁,得出了影响剩磁的主要因素有铁件材质、尺寸、所在位置、测量位置、雷电流大小、冲击条件、次数等,并得出0.5~1.5 mT区间的数据同样可以作为判定依据。而当冲击次数为5次以后,由于铁件的剩磁累积效应,铁件的剩磁量逐步达到饱和。得到的结论为雷灾鉴定工作提供了一定的理论基础。     

Improved steady-state diffusion approximation with an anisotropic point source and the delta-Eddington phase function

Using the algebra transformation method, we develop and demonstrate the use of the delta-P(1) approximation to improve steady-state radiative-transfer estimates on spatial scales comparable to the mean free path. We show that the delta-P(1) approximation agrees well with Monte Carlo simulation from source to infinity when we choose an appropriate parameter f (fractional portion that scatters directly forward) in the delta-Eddington phase function. We also provide the empirical formula to determine the parameter f.     

倒立摆的一种新的控制方法

本文针对水平轨道直线型倒立摆的稳定控制问题,运用基于非线性系统扩展的谐波控制方法,实现了小车的水平位置和摆杆垂直位置的控制.与已有方法比较,此种方法不必对非线性系统进行线性化,系统模型更具真实性.仿真实验表明,本方法能较好地达到控制效果.此种方法也可运用到水平欠驱动机械臂等一类二阶非完整系统的控制中.     

烟草VA菌根化育苗的研究

烟草采用营养袋育苗,育苗土经药剂熏蒸消毒后接种VA菌根菌,是实行VA菌根化育苗的简便有效方法。试验表明,经菌根化的烟苗移栽大田后,促进了烟株对矿质营养的吸收利用及烟叶产量、品质的提高。烟叶中磷含量平均提高21.1%,钾含量平均提高14.6%,烟叶产量平均提高10.4%,上等烟产量平均增加39.1%,烟叶产值平均增加19.2%。烟叶中各化学成分的含量和化学成分之间的比值更趋优质烟的要求,提高了烟叶的内在质量。      

一种新型实用的PLL/DDS混合型短波频率合成器

文章介绍一种新型、实用的短波频率合成器。该频率合成器将国外最新的直接数字频率合成器(DDS)技术和传统的锁相环(PLL)技术有机地结合起来,与多环频率合成器相比,具有线路简洁、设计合理、频率转换速度快、可靠性高等优点;而与普通的单环频率合成器相比,具有更高的频率分辨率和更低的相位噪声。文中分析了该频率合成器的工作原理和设计注意事项,提出了具体的实施方案。     

Robust backpropagation training algorithm for multilayered neuraltracking controller

A robust backpropagation training algorithm with a dead zone scheme is used for the online tuning of the neural-network (NN) tracking control system. This assures the convergence of the multilayer NN in the presence of disturbance. It is proved in this paper that the selection of a smaller range of the dead zone leads to a smaller estimate error of the NN, and hence a smaller tracking error of the NN tracking controller. The proposed algorithm is applied to a three-layered network with adjustable weights and a complete convergence proof is provided. The results can also be extended to the network with more hidden layers.