土地资源的多级网格数据结构建立与应用研究

传统的基于行政区的土地统计数据不能完全表现区域内部土地利用的空间分异特征,以武汉市为实验区,对基于网格的统计信息算法STING(Statistical Information Grid-based method)进行扩展,以景观多样性指数为定量化指标对实验区进行四叉树划分生成不均匀多级网格,建立一种拟合了行政区划界线的不均匀的多级网格结构来存储、管理和分析土地数据。并以此多级网格数据结构为平台计算和生成实验区人口密度空间分异渲染图,初步抽取了人口分布与土地利用之间的关系。实验表明,基于多级网格的统计方法能更好地表达土地利用及其相关数据的空间分异性,利于对土地资源数据的进一步挖掘以抽取所需知识。     

Conservation Threats Due to Human-Caused Increases in Fire Frequency in Mediterranean-Climate Ecosystems

Periodic wildfire is an important natural process in Mediterranean-climate ecosystems, but increasing fire recurrence threatens the fragile ecology of these regions. Because most fires are human-caused, we investigated how human population patterns affect fire frequency. Prior research in California suggests the relationship between population density and fire frequency is not linear. There are few human ignitions in areas with low population density, so fire frequency is low. As population density increases, human ignitions and fire frequency also increase, but beyond a density threshold, the relationship becomes negative as fuels become sparser and fire suppression resources are concentrated. We tested whether this hypothesis also applies to the other Mediterranean-climate ecosystems of the world. We used global satellite databases of population, fire activity, and land cover to evaluate the spatial relationship between humans and fire in the world's five Mediterranean-climate ecosystems. Both the mean and median population densities were consistently and substantially higher in areas with than without fire, but fire again peaked at intermediate population densities, which suggests that the spatial relationship is complex and nonlinear. Some land-cover types burned more frequently than expected, but no systematic differences were observed across the five regions. The consistent association between higher population densities and fire suggests that regardless of differences between land-cover types, natural fire regimes, or overall population, the presence of people in Mediterranean-climate regions strongly affects the frequency of fires; thus, population growth in areas now sparsely settled presents a conservation concern. Considering the sensitivity of plant species to repeated burning and the global conservation significance of Mediterranean-climate ecosystems, conservation planning needs to consider the human influence on fire frequency. Fine-scale spatial analysis of relationships between people and fire may help identify areas where increases in fire frequency will threaten ecologically valuable areas.     

土地经济密度的区域差异特征及动态演变格局——基于长江三角洲地区的实证分析

基于长江三角洲地区25个城市的土地经济密度数据,利用泰尔指数、空间自相关等方法对1995-2007年长江三角洲地区土地经济密度的区域差异特征及动态演化格局进行了初步探索。研究表明：①该区域的土地经济密度总体呈不断上升趋势,但是城市间差异明显,其高值点主要集中于沪苏锡常地区;②土地经济密度的总体差异和区间差异呈现波动性缩小趋势,江苏省内部差异和区间差异是总体差异的主要组成部分;③土地经济密度总体上趋于空间集聚,但局部的空间集聚中心从环杭州湾城市转移到苏南地区和上海。可见,高投入、低效率的土地利用方式已不适合长江三角洲地区的发展,未来必须统筹区域土地利用,合理配置土地资源,促进区域合理分工和协调发展。     

响应面法优化阴阳极同时作用电化学法处理染料废水

在自制电化学反应器中,以甲基橙模拟染料废水为处理对象,采用Box-Behnken Design响应面法研究了影响阴阳极同时作用电化学法处理染料废水的因素及其交互作用。实验得出各因素对废水脱色率影响的大小顺序为：电流密度> Fe³⁺浓度>Cl^-浓度。各因素之间的交互作用对废水脱色率影响的大小顺序为：电流密度和Fe³⁺浓度>电流密度和Cl^-浓度>Fe³⁺浓度和Cl^-浓度。优化结果表明：Fe³⁺浓度为1.02 mmol/L、Cl^-浓度为10.96 mmol/L、电流密度为11.52 mA/cm²时,最佳脱色率为94.67%。阴阳极同时作用电化学法对甲基橙去除效果显著。     

种植密度和降水对冬小麦田N2O排放的影响

为研究种植密度对农田N2O排放的影响和探讨N₂O排放季节性波动的原因,于1999～2000年小麦生长季在南京市郊江宁县进行了不同播种量(0、90、180和270kg/hm²)的大田试验.观测分析结果表明:在相同的气象条件和田间管理下,播种～越冬阶段的N₂O排放不受播种量的影响,返青～成熟阶段的N₂O排放通量与播种量成正比.裸地条件下的N₂O排放与播量为90kg/hm²下的排放无明显差异.造成该生长季内N₂O排放季节性波动的主要原因是降水,返青～成熟阶段的N₂O排放通量随观测日前6d的加权平均降水量呈指数增加.     

INTEGRATING DEMOGRAPHIC AND LANDSAT (TM) DATA AT A WATERSHED SCALE1

ABSTRACT: Recurrent calls for integrated resource management urge that an understanding of human activities and populations be incorporated into natural resource research, management, and protection efforts. In this paper, we hypothesize that watersheds can be a valuable geography for organizing an inquiry into the relationship between humans and the environment, and we present a framework for conducting such efforts. The framework is grounded in the emerging field of landscape ecology and incorporates demographic theory and data. Demography has been advanced by technological capabilities associated with the 1990 Census. Employing Geographic Information System (GIS) tools, we couple Landsat Thematic Mapper (TM) land cover data with census‐derived housing density data to demonstrate the operation of our framework and its utility for better understanding human‐landscape interactions. In our investigation of the Kickapoo Watershed and two sub‐ watersheds, located in southwestern Wisconsin, we identify relationships between landscape composition and the distribution and social structure of human populations. Our findings offer insight into the interplay between people and biophysical systems.     

不同藻密度下诺氟沙星对萼花臂尾轮虫生命表统计学参数的影响

诺氟沙星是一种被广泛使用的抗生素,但其对轮虫的毒性作用尚不清楚。为调查诺氟沙星对轮虫的毒性及其与藻密度之间的关系,以及各试验终点对诺氟沙星污染的相对敏感性,本文以萼花臂尾轮虫为受试生物,研究了不同斜生栅藻密度(1.0×10~6、2.0×10~6和4.0×10~6cells·m L~(-1))下不同浓度(0、5、20、35、50、65和80 mg·L~(-1))的诺氟沙星对其生命表统计学参数的影响。结果显示,与3个藻密度下的对照组相比,暴露于5～80 mg·L~(-1)诺氟沙星溶液中的轮虫生命期望和世代时间显著延长,净生殖率和种群内禀增长率显著提高。5 mg·L~(-1)的诺氟沙星使生命期望和世代时间的延长幅度随着藻密度的升高而增大,但6个处理组的平均提高幅度却随着藻密度的升高而减小; 5 mg·L~(-1)的诺氟沙星对净生殖率和种群内禀增长率的提高幅度随着藻密度的升高而增大,但6个处理组的平均提高幅度却在2.0×10~6cells·m L~(-1)的藻密度下最小,4.0×10~6cells·m L~(-1)的藻密度下最大。1.0×10~6cells·m L~(-1)的藻密度下,诺氟沙星浓度对轮虫后代混交率无显著性影响(P0.05); 2.0×10~6cells·m L~(-1)的藻密度下,暴露于5～35和80 mg·L~(-1)诺氟沙星溶液中的轮虫后代混交率显著降低; 4.0×10~6cells·m L~(-1)的藻密度下,暴露于5、35和80 mg·L~(-1)诺氟沙星溶液中的轮虫后代混交率显著降低。当藻密度为1.0×10~6和2.0×10~6cells·m L~(-1)时,诺氟沙星浓度与轮虫的生命期望、世代时间、净生殖率和种群内禀增长率之间具有显著的剂量-效应关系;当藻密度为4.0×10~6cells·m L~(-1)时,诺氟沙星浓度与轮虫的净生殖率和种群内禀增长率之间具有显著的剂量-效应关系。本研究表明,亚致死浓度的诺氟沙星促进轮虫的存活、发育、孤雌生殖和种群增长,促进作用的幅度受藻密度的显著影响。     

Urban expansion and its contribution to the regional carbon emissions: Using the model based on the population density distribution

The method is used for calculating regional urban area dynamics and the resulting carbon emissions (from the land-conversion) for the period of 1980 till 2050 for the eight world regions. This approach is based on the fact that the spatial distribution of population density is close to the two-parametric Γ-distribution [Kendall, M.G., Stuart, A., 1958. The Advanced Theory of Statistics, vol. 1.2. Academic Press, New York; Vaughn, R., 1987. Urban Spatial Traffic Patterns, Pion, London]. The developed model provides us with the scenario of urbanisation, based on which the regional and world dynamics of carbon emissions and export from cities, and the annual total urban carbon balance are estimated. According to our estimations, world annual emissions of carbon as a result of urbanisation increase up to 1.25 GtC in 2005 and begin to decrease afterwards. If we compare the emission maximum with the annual emission caused by deforestation, 1.36 GtC per year, then we can say that the role of urbanised territories (UT) in the global carbon balance is of a comparable magnitude. Regarding the world annual export of carbon from UT, we observe its monotonous growth by three times, reaching 505 MtC. The latter, is comparable to the amount of carbon transported by rivers into the ocean (196–537 MtC). The current model shows that urbanisation is inhibited in the interval 2020–2030, and by 2050 the growth of urbanised areas would almost stop. Hence, the total balance, being almost constant until 2000, then starts to decrease at an almost constant rate. By the end of the XXI century, the total carbon balance will be equal to zero, with the exchange flows fully balanced, and may even be negative, with the system beginning to take up carbon from the atmosphere, i.e., becomes a “sink”. The regional dynamics is somewhat more complex, i.e., some regions, like China, Asia and Pacific are being active sources of Carbon through the studied period, while others are changing from source to sink or continue to be neutral in respect the GCC.     

生活垃圾塑料分选及利用技术研究

分析了我国城市生活垃圾的组成成分 ,阐述了对我国城市生活垃圾中的废旧塑料进行分选和资源化利用的必要性。提出了从城市生活垃圾中分选塑料和对分选出的塑料进行资源化制板的新技术 ,给出了塑料分选过程的运动参数和板材的性能参数 ,解决了垃圾破碎、缠绕、变重和塑料相容性等关键技术问题 ,制作的板材技术指标符合建筑材料的应用要求。     

Variation in photosynthetic photon flux density within a tropical seasonal rain forest of Xishuangbanna, south-western China

Introduction Photosyntheticphotonfluxdensity(PPFD)withinforestcanopiesisintrinsicallyheterogeneousinspaceandtime.Becausesomespeciesaregenotypicallysuitedforspecificlightregimes,understandingtheheterogeneityofthelightregimewithinaforestcanopyisimportantfor…