O3浓度升高对南方城市绿化树种氮素的影响

近地层臭氧(O3)浓度升高会降低树木的光合速率,抑制Rubisco酶的活性,势必会间接影响树木N素的吸收与分配.本研究利用开顶式气室研究过滤大气(CF,<20 nL·L-1)与O3浓度升高(E-O3,约150 nL·L-1)对10种南方城市常用绿化树种幼苗N素吸收和分配的影响.结果表明,与CF相比,E-O3使枫香叶生物量和马褂木茎生物量分别显著降低了20.9%和21.4%,使枫香和马褂木的根生物量显著降低了24.2%和32.5%.O3对被测树种茎中N素含量影响显著,而对叶和根中N素含量无显著影响.O3对被测树种整株树N素吸收总量(Ntu)、叶片N素吸收量及根的N素吸收量存在显著影响,而对茎N素吸收量无显著影响.与CF相比,E-O3使马褂木与木荷的Ntu分别显著降低了28.4%与22.7%,而使舟山新木姜子Ntu显著增加了15.5%.O3浓度升高对各树种N素吸收量在各器官中的分配无显著影响.     

苏南地区香樟树皮中有机氯农药(OCPs)的污染水平及来源解析

利用树皮作为被动采样介质,2012年8月于苏南地区采集了33个香樟树皮进行有机氯农药(OCPs)的分析.结果表明,苏南地区香樟树皮中六氯苯(HCB)、滴滴涕(DDTs)和氯丹(Chlordanes)的含量范围(以干重计)分别为0.31~1.81、0.40~17.3和n.d.~1.03 ng·g-1.由于六氯苯挥发性较强,其含量的空间差异性不明显.同其它研究结果相比,苏南地区树皮中六氯苯含量相对较低.苏南地区DDT主要来源于工业DDT的历史残留和三氯杀螨醇的使用.根据反式氯丹(TC)/顺式氯丹(CC)的比值判定,苏南地区城区中氯丹可能来源于近期的直接使用,而乡村地区则来源于历史残留.     

A data mining approach to simulating farmers' crop choices for integrated water resources management

Water and land resources in Thailand are increasingly under pressure from development. In particular, there are many resource conflicts associated with agricultural production in northern Thailand. Communities in these areas are significantly constrained in the land and water management decisions they are able to make. This paper describes the application of a data mining approach to describing and simulating farmers' decision rules in a catchment in northern Thailand. This approach is being applied to simulate social, economic and biophysical constraints on farmers' decisions in these areas as part of an integrated water management model.     

最小割集在系统安全分析方法中的应用

利用事故树分析法对矿井火灾进行分析 ,结合平煤六矿建立了矿井火灾事故树。阐述了最小割集理论及其在事故分析中的作用 ,着重提出了对事故树底部事件进行排序分级的加权结构重要度分析法。该方法新颖、简洁而实用 ,为系统安全分析提供了新的方法和途径。     

武进区花卉苗木基地产业生态化建设方案研究

苏南地区的快速城市化在带动地方经济大发展的同时，却给农村环境造成了巨大的压力，如何实现农村环境与经济协调发展是亟待研究的任务。江苏省常州市武进区花卉苗木基地的实践表明，对区域做出科学的生态经济区划，在严格保护基本农田的基础上，充分利用其它类型的土地资源因地制宜地发展花卉苗木生态产业，成为农村生态环境建设的优化途径之一。武进花木基地环境建设包括：(1)优化生态经济区划，将整个基地划分为平原水网和漏湖圩田两个生态经济区；(2)根据各生态经济区的不同特点采取相应的生态产业布局和实施方案；(3)发展具有“水乡、花卉、休闲”特色的生态旅游产业。     

黑龙江大兴安岭主要树种燃烧性及理化性质的实验分析

森林可燃物的燃烧性和理化性质取决于构成森林的树种。该文对黑龙江省大兴安岭16个树种着火特性和成分进行了测定,分析了树种之间及树叶、小枝和皮之间在这些指标上差别,得出了反映树种之间及结构之间的一些规律,并对发热量影响因子进行了分析,建立了回归方程。这些为研究森林着火、蔓延、能量释放、火强度测算及防火树种筛选提供依据。     

Using slides to test for changes in crown defoliation assessment methods part II: Application of the image analysis system CROCO

We tested whether the semi-automatic program CROCO can replace visual assessments of slides to detect changes in defoliation assessment methods. We randomly selected a series of slides of 24 Norway spruce trees with 220 field assessments made between 1986 and 1995. The slides had been randomly arranged and assessed by three experts without knowledge of the tree number or the year when the slide was taken. Defoliation scores were computed with CROCO. Each tree had thus three different defoliation scores, field assessments, photo assessments and CROCO scores.CROCO scores were less correlated with the field assessments (Spearmans rank correlation: 0.67) than were the slide assessments with the field assessments (0.79–0.83). However, CROCO was not biased against the field scores, while slide assessments systematically underestimated defoliation.In a multi-variate mixed effect model none of the variables tree overlap, tree visibility and light conditions was significant in explaining differences between slide assessors and CROCO scores. The same model applied for the differences from the field scores yielded significant effects for poor light conditions (CROCO and all assessors), for crown overlap (CROCO and one assessor) and for visibility (one assessor). We conclude, therefore, that CROCO can be used to detect past and future changes in assessment methods without bias if poor quality photographs are avoided.     

西藏尼洋河流域果树资源及其开发途径探讨

西藏尼洋河流域果树资源丰富,栽培果树有苹果、梨、桃、李、杏和葡萄等9种和90多个品种;野生果树有7科16属41种,目前利用程度低,开发潜力大。文中提出了该地区果树资源的开发途径,在尼洋河下游和雅鲁藏布江的扎绕乡至派乡之间段的河谷地上形成“Y”字型的水(干)果种植带,建设成为西藏的水(干)果生产基地,并对现有果园改造更新,充分利用野生水果资源,建立果品综合加工厂等以满足西藏市场对水果和果品的需要。     

Air Pollution Effects on Annual Ring Widths of Forest Trees in Mountainous Land of Izmir (Turkey)

Annual ring widths of forest trees are affected from different ecologicalfactors (e.g. climate, soil, etc.) and also from air pollution. In the areas with intensive air pollution annual ring width reductions are observed. For this reason, some methods which detect the annual ring widths, in other words, the increase or decrease in diameter increments, are used to examine air pollution. Industrial establishments found in the northern part of Izmir city (Aliaga region) affect air quality of this area negatively. In this investigation, annual ring widths of 13 Pinus brutia Ten. (Calabrian pine) and 20 Pinus nigra Arnold. (Austrian pine) from 4 mountains (Karabelen, Manisa, Kemalpasa, and Yamanlar) with different altitudes and exposures around Izmir city were detected and the effects of air pollution on these trees were determined. Intensive effects of air pollution have started in 1985, for that reason, annual ring widths were examined through a reference period before this year and a study period (1985–1998) after this year and results are statistically evaluated. Annual ring widths of tree samples in the northern exposure were affected from air pollution, and some reductions were observed. These reductions increased when there is a long drought period.     

考虑贮存剖面的固体火箭发动机橡胶密封圈贮存寿命研究

目的 对贮存周期内包含多个温度环境剖面的固体火箭发动机橡胶密封圈贮存寿命进行评估。方法 通过开展硅橡胶材料加速老化试验,结合Arrhenius老化规律,建立硅橡胶老化模型,获得硅橡胶加速老化等当规律,并根据等当关系开展模拟密封装置加速老化试验,考核老化后硅橡胶密封性。最后通过对固体火箭发动机贮存环境剖面进行梳理,计算出贮存周期下的等效温度,并结合试验获得的硅橡胶密封圈老化性能,直接对该贮存周期下密封圈老化寿命进行评估。结果 通过硅橡胶材料老化试验及模拟密封装置老化试验,得到了25℃下硅橡胶能够满足20 a的使用寿命。随后通过梳理并计算得出固体火箭发动机贮存周期下的等效温度为22.78℃,可以直接获得该发动机使用的硅橡胶密封圈寿命在该贮存环境下能够满足20 a使用寿命。结论 通过计算贮存周期下多个温度环境剖面的等效温度,并结合加速老化试验结论,可快速获得橡胶密封圈老化寿命。