Determination of trophic relationships within a Bohai Bay food web using stable δ15N and δ13C analysis

This study measured stable carbon and nitrogen isotope ratios in phytoplankton, zooplankton, five invertebrates species, eight fishes species and three seabirds species collected in Bohai Bay. δ^13C ranged from -25.38‰ to -11.08‰ showing a relative low enrichment in the food web from Bohai Bay. The mean δ^13C of mullet is higher than that of other organisms, and this might be due to that mullet is migration fish and feeds mainly on inshore sources. δ^15N ranged from 4.08‰ to 13.98‰, and showed a step-wise enrichment with trophic level of 3.8‰. The δ^15N enrichment factor was used to construct an isotopic food web model to establish trophic relationships within this marine food web. According to this model, exact trophic levels of all organisms were estimated as 1.46-2.10, 1.91-3.32, 2.55-4.23 and 2.98-4.28 for plankton, invertebrates, fishes, and seabirds.     

降雨条件下车载激光雷达感知局限性

针对激光雷达在降雨条件下的性能局限性问题,基于封闭场地中的降雨模拟设施,分别选取一款机械旋转雷达和混合固态激光雷达采集不同降雨条件下的点云数据,通过构建包括5项客观指标的指标集,对两类激光雷达受降雨条件影响的程度进行了对比分析。试验结果表明,降雨会在一定程度上减少点云的数量,降低点云的反射率,增加反射率信息熵,降低反射率信噪比;降雨的雾化现象会大幅恶化激光雷达的表现,在20m~40m内,对机械旋转雷达造成91.49%的平均点云数量削减和82.98%的平均反射率削减;而波长较长、非重复扫描的混合固态雷达在降雨下具有更好的穿透性,点云数量较为稳定;但混合固态雷达在降雨环境下的点云会包含更多反射率较低的雨滴回波,因此需要采用更有效地噪声滤除算法。     

远中号八倍体小偃麦及中间偃麦草的SDS-PAGE和A-PAGE分析

利用ＳＤＳ－ＰＡＧＥ和Ａ－ＰＡＧＥ对远中号异源八倍体小偃麦（中１－中７）及其父本中间偃麦草进行了遗传分析,讨论了八倍体小偃麦中１－中７在ＳＤＳ－ＰＡＧＥ和Ａ－ＰＡＧＥ电泳图谱中中间偃麦草的生化标记。     

中型载货汽车使用可靠性研究

结合我国中型载货汽车运行生产实际,借助于可靠性理论、更新理论、优化理论等,推导计算出我国EQ1090和CA1091两种中型载货汽车使用中可靠性特征量的估计值和观测值．     

济南四大泉群水源地连通试验研究

在济南四大各主要渗漏地段的东南、南、西南４００多ｋｍ＾２范围内,进行了连续多次的大规模的泉水来源连通试验,较全面地查清了泉水的来源情况,摸清了岩溶发育地区地下水流的运行规律,取得了满意的结果,为拦拱蓄水参漏保泉提供了直接证据,为同类研究提供了参考。     

Progress on molecular self-assembly of alkanethiols

Molecular self-assembly became an interesting research project which was paid much attention by many scientists. This article briefly tells readers thc suggestion, principle and the newest progresses on self-assembly. It introduces the progresses on molecular self-assembly of alkanethiols in detail.     

An Sm-Nd isotopic dating study of the Archean Kongling Complex in the Huangling area of the Yangtze Craton

Sm Nd isotopic compositions of associated amphibolites, TTG gneisses and granitic gneisses from the Archean Kongling Complex of the Yangtze Craton, South China are systematically analyzed. The results show that the amphibolites and TTG gneisses have a similar age of ca. 2 700 Ma, which well agrees with zircon U Pb dating of previous studies. However, their ε Nd ( t ) are different, suggestive of possible dissimilarity in source composition.     

斜等距曲面在球面铣刀制造中的应用

针对球面铣刀后刀面的几何形状问题,提出了斜等距曲面的概念,解决了球面铣刀制造中模型过于复杂的问题。     

UCDOS特显功能在数据库设计中的应用探析

本文从分析UCDOS特殊显示原理出发,阐述了UCDOS特殊显示功能在数据库管理语言FoxBASE中的应用,最后总结了其使用模式。     

基于系统论的土地利用多功能分类及评价指标体系研究

基于系统论中要素–结构–功能原理, 对土地利用系统多功能进行系统识别和分类, 建立土地利用多功能分类体系; 从经济–社会–生态维度构建多尺度、多层次的土地利用多功能评价指标体系, 并对指标数据的获取和空间化方法进行初步探讨。结果表明, 土地利用多功能具有多层次性和区域性, 应针对不同的区域背景和研究尺度建立相应的分类与评价指标体系。将土地利用功能与土地利用结构相联系, 并将评价尺度延伸至地块这一微观尺度, 拓展和丰富了土地利用多功能研究的范围与内容, 为土地利用多功能研究提供新的思路和途径。