江西九连山自然保护区常绿阔叶林的结构特征

基于线路和样方调查的基础上分析了九连山国家级自然保护区常绿阔叶林的结构特征。优势科主要为壳斗科（Fagaceae）、樟科（Lauraceae）、山茶科（Theaceae）、安息香科（Styracaceae）、杜鹃花科（E6caceae）、木兰科（Magnolicceae）、槭树科（Aceraceae）、枫香科（Altingiaceae）、冬青科（Aquifoliaceae）、厚皮香科（Temstroemiaceae）、柿树科（Ebenaceae）、桃金娘科（Myrtaceae）、杜英科（Elaeocarpaceae）等科,优势树种也以相应的优势科属树种为主。调查中,胸径DBH≥3cm的乔木个体密度1808株／hm^2;优势层相对较高大,平均高度达到11．5m;乔木垂直分化较明显,树种水平分布不均。九连山现状植被是天然原生植被、次生植被和人工植被的混合体,并常见有阳性落叶树如枫香（Liquidambar,formosana）、拟赤杨（Alniphyllum fortunei）、光皮桦（Betula luminifera）等侵入林窗,形成常绿与落叶阔叶树的混交林。     

一种基于FTU的馈线自动化系统

本文介绍了一种基于FTU（现场终端装置）的馈线自动化,探讨了馈线自动化的主要功能、实施的先决条件：并就一次设备、控制箱（FTU）、通信系统、FA控制主站及SACDA（配电管理系统）主站等五个层次讨论了基于FTU馈线自动化系统的构成,同时介绍了基于FTU模式下的故障处理,指出馈线自动化是提高配电网络电能质量、供电可靠性的有效手段。     

Spatial epidemiology of networked metapopulation: an overview

An emerging disease is one infectious epidemic caused by a newly transmissible pathogen, which has either appeared for the first time or already existed in human populations, having the capacity to increase rapidly in incidence as well as geographic range. Adapting to human immune system, emerging diseases may trigger large-scale pandemic spreading, such as the transnational spreading of SARS, the global outbreak of A（H1N1）, and the recent potential invasion of avian influenza A（H7N9）. To study the dynamics mediating the transmission of emerging dis- eases, spatial epidemiology of networked metapopulation provides a valuable modeling framework, which takes spatially distributed factors into consideration. This review elaborates the latest progresses on the spatial metapopula- tion dynamics, discusses empirical and theoretical findings that verify the validity of networked metapopulations, and the sketches application in evaluating the effectiveness of disease intervention strategies as well.     

The spatial distribution pattern of landslides triggered by the 20 April 2013 Lushan earthquake of China and its implication to identification of the seismogenic fault

After the 20 April 2013 Lushan MS6.6 earthquake occurred,investigation and identification of the seismogenic fault for this event have become a focused and debatable issue.This work prepared an initial landslide inventory map related to the Lushan earthquake based on field investigations and visual interpretation of high-resolution aerial photographs and provided evidence for solving the issue aforementioned.The analysis of three landslide-density profiles perpendicular to strike direction of the probable seismogenic fault shows that many landslides occurred on the footwall of the Shuangshi–Dachuan fault(SDF),without sudden change of landslide density near the fault.Very few landslides were detected near the Dayi fault(DF)and also no change of landslide density there.While obvious sudden change of landslide density appeared about 1–2 km from the northwest to the western Shangli fault(WSF),and the landslide density on the hanging wall of the fault is obviously higher than that of on the footwall.Therefore,we infer that the seismogenic fault for the Lushan earthquake is neither the SDF nor the DF,rather probably the WSF located between these two faults,which is an evident linear trace on the earth surface.Meanwhile,the coseismic slip did not propagate upward to the ground,implying the Lushan earthquake was spawned by a blind-thrust-fault beneath the WSF.     

Spatiotemporal pattern and regional characteristics of visibility in China during 1976–2010

Degradation in visibility occurs extensively across China,creating the urgent need to better understand visibility patterns and characteristics in China.Using daily observation data from the U.S.National Climatic Data Center(NCDC)during 1976–2010,the spatial distribution and temporal trends of visibility in China,as well as seasonal and regional characteristics,were determined.The distribution of visibility was characterized by a longitudinal gradient between west and east China.The northwest of China generally experienced consistent high visibility of[20 km,while central and eastern China experienced visibility degradation and increase in haziness.The 133stations with significant downward trends in visibility were clustered around central-east China and the average reduction rate was-1.65 km/decade(from 18.5 km).The96 stations with increasing trends of visibility were mostly on the Qinghai–Tibet Plateau and Xinjiang and were closely related to a reduction in local sand storms.The average visibility in 12 key regions in China varied between9.9–17.8 km(except for 23.9 km in Urumqi),which was lower than the national average of 18.7 km.The Taiyuan–Hohhot,Guanzhong,Yangtze River Delta,Pearl River Delta and Fuzhou–Xiamen areas all encountered significant decreases in visibility,while minor increases were observed in Beijing–Tianjin–Hebei and the Cheng-Yu region.At most stations,the worst visibility was measured in winter,but the season with best visibility varied between regions.A comparison of visibility trends with the emission trends of various pollutants revealed that SO2emissions dominated the visibility degradation in eastern Chinawith NOxand volatile organic compounds playing ascending roles during the 2000s.     

估计跳频信号参数的多窗口迭代平滑伪WVD新算法

采用时-频分析方法获取跳频信号的瞬时频率、跳周期、跳频图案等主要参数,在短时傅立叶变换、Wigner-Ville分布等传统时-频分析算法均无法达到抑制噪声和实时参数检测的情况下,提出一种能适应跳频信号速率变化的多窗口迭代平滑伪Wigner-Ville分布(SPWVD)算法来进行跳频信号参数的实时估计。仿真结果表明,该算法在较低信噪比(-8 dB)的情况下也具有良好的实时估计效果。     

区域性皆伐抚育作业对沙柳林地土壤养分空间异质性的影响*

针对毛乌素沙地沙柳林以区域性皆伐作业为主的采伐方式,研究皆伐干扰对林地土壤养分和有机质含量的空间变异特性的影响,为开展灌木林生态采伐理论奠定前期基础。在对照设立皆伐和未采伐两组样地上,按照空间格局分析技术中多样点、小支撑的取样原则,用土钻取样地表层(0~15 cm)土样,实验室测定土样的全氮、全磷、全钾和有机质碳的含量;运用SPSS和GS+软件进行数据分析。数据结果如下:受皆伐干扰的样地养分含量高于未采伐样地,受皆伐干扰的样地的土壤全氮和有机质含量升高最为明显,平均值为未采伐样地的1.47和1.12倍。两者表层全氮、全磷和全钾的含量均能很好地拟合成球状模型;皆伐扰动并未使土壤养分的空间自相关度降低,空间自相关性引起的异质性占总异质性的75%以上;采伐干扰使磷、钾养分的变程减小(分别降低26.5%和27%),林地养分呈现出中小尺度的空间变异特征;通过土壤养分空间异质性分析得出:对沙柳灌木林进行区域性皆伐的抚育措施,可使林地的土壤环境得以改善,利于沙柳林的可持续经营。     

杂谷脑河流域薛城段地质灾害分布特征与影响因素

杂谷脑河流域薛城段地属川西北中、高山区,地质环境脆弱,尤其是在汶川大地震之后,该区域内的崩塌、滑坡及泥石流地质灾害更加发育,是杂谷脑河流域地质灾害高易发区。通过对该区域详细的地质调查测绘,分析和总结了该区域地质灾害的分布特征以及影响因素,得到的主要结论有:1该区域地质灾害具有带状分布、密度大、规模大、高程分布集中及雨季多发的特征;2该区域地质灾害与地形地貌关系密切,多发育在坡度26°~40°,坡向135°~224°和270°~360°及坡高64~663m的范围内;3不同的岸坡结构控制着不同的地质灾害的分布,滑坡多分布在逆向坡和斜向坡中,而崩塌多分布在横向坡和顺向坡中;4地层岩性对地质灾害的分布有着直接的影响,该区域地质灾害主要分布在千枚岩、变质砂岩、砂质板岩中;5人类工程活动对该区域的地质灾害有着较大的影响。     

配送中心补货作业问题的蚂蚁算法

补货是配送中心运作中一项重要的作业,对其有效管理能够显著减少配送中心的运作时间,带来可观的经济效益. 根据配送中心的具体配置,补货作业呈现不同的模式,本文探讨配送中心分拣区采取指定储存策略情形下,补货设备从储存区补充物品到拣货区的补货作业问题,运用蚂蚁寻找最优路径算法原理设计出解决该问题的算法步骤与流程,并仿真测试算法性能,计算结果显示效果良好.     

基于频率比-投影寻踪模型的渝东北三峡库区滑坡敏感性制图

滑坡敏感性制图是灾害防治较为有效的软措施之一。以渝东北三峡库区为例,利用频率比法和投影寻踪模型绘制滑坡敏感性图。首先,针对研究区的地质环境特征建立滑坡敏感性评价指标,并利用频率比法分析历史滑坡与指标之间的空间关系。其次,利用投影寻踪模型确定评价指标的最优向量,将频率比分析结果与最优向量进行加权计算得到滑坡敏感性指数,并将其划分为高敏感区、较高敏感区、中敏感区、较低敏感区和低敏感区。最后,利用接受者操作特征(receiver operating characteristics, ROC)曲线验证了滑坡敏感性制图结果。结果表明,频率比-投影寻踪模型在滑坡敏感性制图中具有良好的性能,样本和验证数据的曲线下面积(area under the curve, AUC)值分别为0.844和0.763。研究区滑坡敏感性以中低风险为主;较高和高风险区面积约占22%,主要分布在忠县、万州以及巫山等区县的人类工程活动集中区。研究结果可为区内灾害防治提供参考,有助于提升三峡库区地质灾害防灾减灾保障能力。