三种丛枝菌根真菌对百喜草生长、矿质元素含量及抗旱性的影响

研究了三种丛枝菌根(AM)真菌Glomus Aggregatum(G.a)、G.etunicatum(G.e)和G.intraradices(G.i)对百喜草(Paspalum notatum)生长、矿质元素含量及干旱胁迫下几种生理指标的影响.3种AM真菌处理显著提高了主根长和地上部干重,菌根依赖性依次为G.a>G.i>G.e.G.a和G.e接种株根部P、K、Mg、Cu含量,G.i接种株根部P、Mg、Ca含量及G.e接种株根部Ca含量均显著高于对照;G.a接种株地上部P、K、Mg、Ca和Zn含量与对照无显著性差异,而G.e和G.i处理的地上部P、K、Mg、Ca和Cu含量均显著低于对照.干旱胁迫4d时,G.a和G.e处理的地上部POD活性、G.a处理的地上部脯氨酸含量均显著高于对照.干旱胁迫8 d时,各接种株的SOD和POD活性与对照并无显著性差异,而接种AM真菌显著提高了地上部脯氨酸含量,G.e和G.i处理的MDA含量显著低于对照.三种AM真菌以G.a接种处理一定程度上提高了百喜草的生长及抗旱性,而G.e和G.i的效果相对较弱.     

对新旧版《公路工程勘察设计招标文件》编制的体会

文章通过新旧版招标文件对比发现,新版招标文件增加了投标人与其他单位资产关联、隶属关系框图,有效避免了投标人与招标人均为同一集团公司的下属公司及自行招投标的情况发生.     

预应力混凝土结构孔道摩擦系数κ和μ值实测分析

文章通过预应力混凝土梁实测数据并参考了国内外的相关研究资料。对预应力束的孔道摩擦系数κ和μ值进行了较深入的分析。对影响摩擦系数的因素进行了探讨,认为我国规范取值偏小,文章给出了实际摩擦系数取值的建议。     

一种新改进的DS/CDMA多用户检测器

提出了一种利用盲信号分离技术(BSS)与RAKE接收相结合的新多用户检测器.利用基于高阶累积量快速定点的独立分量分析(ICA)算法,从CDMA系统的多址干扰信号中较好地分离出需要用户的多径混合信号和多址干扰信号,进而通过RAKE接收需要的用户信号.     

用ASP和SQL Server建立高校科研信息管理系统

根据高校科研管理的特点对高校科研管理信息系统的需求进行了研究,提出了采用微软公司的ASP SQL Server系统的解决方案,该方案采用B rowser/Server结构,浏览器的客户端无需安装任何组件,就可以使用本系统的所有功能;探讨了该解决方案的需求分析、程序设计、程序测试的全过程,系统总结了建立高效率科研管理信息系统的方法.     

A Class of Second-Order Consensus Protocol in Multi-Agent Systems with Multiple Input Delays

This paper is concerned with the consensus problems for second-order multi-agent systems with multiple input delays. Different from all standard consensus algorithms with uniform delays, the authors aim to find the largest input-delay margin which can guarantee the consensus for the case when delays are nonuniform. Based on frequency domain analysis and matrix theory, an upper bound for maximum tolerable input-delay is given in terms of the relationship with scaling strengths and largest eigenvalue of the Lapalician matrix. Simulation results are provided to illustrate the obtained results.     

基于SolidWorks 渐开线齿轮的三维辅助设计

探讨了基于SolidW orks的二次开发技术,研究如何利用V isual Basic程序语言在SolidW orks中强大的三维绘图功能进行计算机三维辅助设计;并以渐开线齿轮的设计与绘制为例,提出了通过程序计算后利用SolidW orks曲线连接阵列点构建封闭齿廓的方法。实践证明该方法为其它CAD二次开发平台绘画渐开线齿轮提供可借鉴之处。     

窖水中主要无机离子对光催化灭除大肠杆菌(E.coli)的影响研究

采用自主开发的N-TiO_2作为光催化剂,在流动相光催化反应装置中,对窖水中所含Ca~(2+)、Cl~-、CO_3~(2-)、HCO_3~-、SO_4~(2-)等主要无机离子对光催化剂灭除E.coli的影响,以及复配模拟窖水和实际窖水对光催化灭除E.coli的影响进行了实验研究,并分析了其影响机理。实验结果表明:Ca~(2+)、HCO_3~-对光催化灭除E.coli有抑制作用,CO_3~(2-)对光催化灭除E.coli有明显的促进作用,而SO_4~(2-)、Cl~-对光催化灭除E.coli无影响。在对实际窖水进行光催化灭除E.coli菌落总数的实验中,经60min反应,窖水中菌落总数和总大肠菌群均为零,达到国家饮用水卫生标准,说明自主开发的NTiO_2光催化剂在农村窖水深度处理灭除E.coli效果好,可推广应用。     

Diet composition of an invasive population of Lithobates catesbeianus (American Bullfrog) from Argentina

The American bullfrog Lithobates catesbeianus has been introduced around the world, with invasive populations reported from almost all South American countries. A population of this species was introduced in the Calingasta department of San Juan province, which is an arid environment in western Argentina. This work provides information on the dietary composition of an invasive population of L. catesbeianus, and compares the degree of dietary overlap between adults and juveniles. Stomach contents of 169 bullfrogs (82 adults and 87 juveniles) were analysed. Adults consumed 40 prey taxa and Hymenoptera (Insecta) was the most numerous prey item (41.8%), followed by Araneae (13.6%) and Aeglidae (13.4%). Juveniles consumed 29 prey taxa and Hymenoptera constituted the highest percentage in prey number (77.2%). The trophic overlap niche index at the same level shows a value of 0.64 overlap in dietary community between adults and juveniles of this bullfrog. Aeglidae was volumetrically the most important trophic item (25.4%), followed by Anura (25.02%). Our results showed that cannibalism in bullfrogs is more common than the consumption of native anurans, coinciding with that reported in other populations of introduced bullfrogs. The high similarity in the diets of both size classes and the association between the size of the predator and prey suggest that the impact caused by bullfrogs throughout their ontogeny is high and probably has an impact on their prey. Freshwater crabs are the main items in the diet of Lithobates catesbeianus in other introduced populations and are usually the most conspicuous at our study site. The crabs in freshwater ecosystems are part of the lowest trophic level in the food chain. The major threats to the southern region’s freshwater crabs include deforestation, farming and exotic species. Lithobates catesbeianus has a generalist diet and high overlap between adults and juveniles.     

玉米套种的栽培技术要点

简要介绍了玉米套种甘蓝复播架豆角的栽培技术及其收益.