群组型港口城市用地时空扩展特征及外部形态演变--以宁波为例

以多时相Landsat MSS、TM和ETM卫星影像为数据源,提取宁波城市各组团(三江片、镇海片和北仑片)多时相的用地信息,分析了港口城市用地扩展的时空特征及外部形态演变过程。结果表明:(1)1979年以来,宁波城市用地面积扩展速度和扩展强度不断提高,但各个组团的表现有较大的差异。(2)各组团城市用地空间结构分维数的波动与城市用地的空间扩展模式表现出明显的相关性。(3)3个组团的城市用地扩展强度指数峰区相对城市质心有不断外移趋势,但扩展强度指数峰值的变化在各个片区有一定差异。(4)3个组团城市用地外部形态演变在不同方向上的差异性与宁波港口迁移及港口经济的发展密切相关。(5)随着宁波港口从内河港向河口港、海岸港的迁移,宁波城市外部形态演变经历块状单一集中型内河港城市、"一城一镇"飞地式群组河口港城市、"一城二镇"飞地式群组海港城市和"一城多镇"不连续带状群组海港城市发展阶段,最后将形成"T"型带状群组现代化国际港口城市。

辽宁中部群组型城市空间结构演变分析

基于遥感数据、地形图和统计数据提取城市用地信息，采用指数分析、GIS空间分析和地统计分析方法研究了1954年、1975年、1986年、2000年和2005年5个时期辽中群组型城市用地特征。结果表明：1954年以来城市用地不断增加，1954～1975年城市扩张最快，但不同城市扩张速率和趋势不尽相同；1986～2005年城市间的相互作用强度成倍增加，城市化发展的空间辐射作用增强，沈阳市作为区域中心城市，城市化水平和作用不断突显，一些城市明显向沈阳市方向移动；1975～2000年小城镇快速发展；较高城市空间年增长率分布区域与城市重心转移方向基本吻合。并分析了成因。

基于群组型城市干线公路发展规划研究——以常州市为例

公路尤其是普通干线公路在引导城市发展、划定城市发展边界、推动完善城镇功能等方面发挥了至关重要的作用。本次研究主要在现代化群组型城市模式下,从各组团的发展阶段和规划定位解读入手,对各组团的交通需求特点逐一进行分析,确定干线公路过境城市的规划方案。

趣缘型互联网群组的意识形态风险透视与应对理路

趣缘型互联网群组是基于共同兴趣爱好或价值观念的群体在网络虚拟空间因“趣”成群的网络样态,是组员集兴趣爱好、交友娱乐、资源分享、学习探讨、情感交流、身份认同于一身的归属地和承载地。然而,在内容、组织和传播向度上分别存在流量至上消解主流思想认同、圈群样态冲击主流舆论格局、错误思潮撕裂主流价值共识等意识形态风险。因此,应从价值引领、组织协同、技术赋能等方面着力,推动主流文化与群组文化的内容互构,汇聚建设群组主流意识形态监管合力,实现主流意识形态在群组的破圈传播。

Effects of seasonal variations on soil microbial community composition of two typical zonal vegetation types in the Wuyi Mountains

Seasonal shifts play an important role in soil microbial community composition. This study examined the hypothesis that soil microbial community structure would vary with seasonal shifts in the Wuyi Mountains in Southeast China, and that two representative tree species （Castanopisi carlesii and Cunninghamia lanceolata） may have different soil microbial community composition. Phospholipids fatty acid analysis （PLFA） of seasonal shifts and was used to assess the effect vegetation types on soil microbial community structure. A total of 22 different PLFAs were identified from all the soil samples. The bacterial PLFAs accounted for 62.37% of the total PLFAs, followed by fungi （28.94%）, and the minimum was actinomycetes （6.41%）. Overall, the level of PLFAs in C. carlesii soil was greater than those in C. lanceolata soil, and significant differences were observed in some seasons. The amounts of total, bacteria, actinomycic and fungal PLFAs significantly changed with the seasons and followed a sequence order （summer 〉 autumn 〉 spring 〉 winter）. The bacteria/fungi PLFAs and G （＋）/G （-） PLFAs of two vegetation types also changed with the seasons and the ratios in summer and autumn were higher than those in spring and winter. The correlation analysis of microbial PLFAs and soil physicochemical properties showed that the total, bacteria, fungal, actinomycic, G （＋） and G （-） PLFAs were significantly positive correlation with TOC, TN, TP, TK and moisture content. We concluded that the seasonal shifts and vegetation types affect soil microbial community composition by changing the soil physicochemical properties.

Response of meiofaunal and nematode communities to sewage pollution abatement:a field transplantation experiment

To assess the recovery rate of meiofaunal and nematode communities upon abatement of sewage pollution, a field transplantation experiment was conducted in Tat Tam, which is a non-polluted, shallow subtidal habitat on the southern portion of Hong Kong Island. The sediments used were from one site located in Victoria Harbour that was heavily influenced by sewage pollution, and one site in the outside-harbor area, which was relatively clean. In addition, sediments from Tat Tam were used as a control. Fresh sediments with meiofauna were collected from the aforementioned sites, placed in plastic trays and transplanted to Tat Tam. Sediments were retrieved at the beginning of the experiment and at 1-, 3-, and 8-weeks after transplantation for analysis of the meiofaunal and nematode communities as well as the sediment characteristics. The results showed that the meiofaunal and nematode communities in the control sediments were consistent at the four sampling periods, while it took three and eight weeks, respectively, for the nematode communities from the outside-harbor and inside-harbor sites to become similar to the control. These findings indicated that the relatively poor habitat quality and the nematode community composition in the sewage polluted inside-harbor sediments required a longer time for recovery than samples from the better habitat quality and the nematode community composition in the outside-harbor sediments.

Effects of a patchy seagrass meadow on the macrobenthic community

Based on macrobenthos collected from intertidal seagrass bed in Guangrao,Shandong Province in May 2013,the macrobenthic structure and diversity were analyzed.A total of 41 macrobenthic species were identified,among which crustaceans were the most speciose macrobenthic taxa(16 species),followed by polychaetes(15 species)and mollusks(10 species).Seven dominant macrobenthic species were identified,including 3 species of polychaetes,2 species of crustaceans and 2 species of mollusks.The total abundance across the whole sampling area was 661.33 ind/m2.Total abundance and the abundance of Potamocorbula laevis and Heteromastus filiformis showed significant spatial variation,and the macrobenthic abundance distributed in seagrass meadows was higher than that in other areas.The results of cluster,nMDS ordination,SIMPER and IMS analyses all showed no linear correlation along the distance gradient from the seagrass meadow.Therefore,degraded seagrass can still provide detectable but limited ecological services.However,the rehabilitation of seagrass bed is essential and urgent to regain their full ecological function.

结合路段和网眼结构的路网模式识别方法

道路网具有鲜明的空间分布模式,其模式识别在地图制图、地图匹配及空间查询等诸多领域均发挥着至关重要的作用。当前的路网模式识别方法多基于网眼结构与路段结构两种模型,取得了较好的识别效果,但亦存在一定局限。已有的基于网眼的识别算法往往局限于最小单元的格网模式,无法对整体规则、局部破碎的网眼群组进行模式识别;而基于路段结构的模式识别则涉及复杂的预处理与识别过程,并且仅能识别单一的路网模式。方向熵作为信息熵的一个分支,可以较好地描述地理数据的空间分布特征和规律。为此,本文结合了网眼结构在网眼规整情况下的识别优势和路段结构在分析路段排列方式方面的优势,在此基础上引入方向熵、矩形度和凹凸度等特征参量,构建了一种有效的路网模式识别算法。本文选取多个城市路网作为实验对象,通过计算出不同路网模式相对应的参量分类阈值,实现了格网模式和不规则模式路网的模式识别,且根据格网模式路网中网眼群组排列方式的不同,构建网眼质心最小生成树并使用方向熵将其细分为直线型网眼群组和格网型网眼群组。实验结果表明,结合路段和网眼结构的路网模式识别算法的模式分类精度达到了97%以上,能够有效完成典型路网模式的识别并较好地根据网眼群组的排列方式完成了格网模式的细分。与现有路网模式识别方法比较,本文构建了一种简单快速且较为精准的路网模式识别算法,为地图综合、模式识别和城市规划等领域的后续研究和应用提供了一种新的思路。

生物似然的运动伪装理论与应用研究

引入了生物似然的运动伪装理论,介绍了个体型与群组型模型的特点,指出了各模型运动伪装实现的关键。针对图像隐现效应,结合可见光和红外探测原理,给出了隐现抑制建议。分析表明,运动伪装理论可能成为辅助空中飞行器隐身的重要手段。