室内空气污染对人体健康的潜在危害

本文就室内空气污染对人体健康产生危害的几个主要方面进行了阐述 ,并提出了相关的防治措施和建议     

室内环境空气中甲醛的污染与分析

本文在对各类民用工程建筑室内环境空气污染物进行检测的基础上,分析了室内环境空气中检出率最高的甲醛污染物的来源,并阐述了对人体所产生的危害以及降低室内环境空气中甲醛浓度的措施.     

室内空气污染的危害及其主要成因

室内空气污染状况日趋严重,会形成几种危害人体的症状,已成为对人类健康的10大威胁之一。室内空气污染主要来自装饰材料、家具和建筑物自身、室外污染物、燃烧产物和人体挥发等因素也不容忽视。应注重现代住宅的5项卫生标准加以防治。     

不同放牧强度对红三叶、黑麦草草地植被和土壤养分的影响

对不同放牧强度下草地植物和土壤的变化规律进行了研究，结果表明：３年强度放牧使土壤的全氮含量和草地的组成和结构发生了较大的变化，使牧草产量下降１７．１％，草地主要种红三叶的重要值降低了３３．８％，均质度系数增加５１．１％，土壤的氮磷比升高１．３。轻度放牧使草地全氮含量降低０．０９６％，红三叶的均质度系数增加２１．０％。中度放牧并未使草地牧草产量和红三叶的重要值降低，同时使草地红三叶均质度系数保持在远低于１．０水平以下，但使土壤全氮含量下降０．０８５％。根据以上结果，中度放牧是保持草地持续高产的最好的放牧管理选择。     

基于人工神经网络的森林资源管理模型研究

介绍了人工神经网络方法，建立了森林资源管理的三层前馈反向传播神经网络模型，并与Ｌｏｇｉｓｔｉｃ函数进行了比较。仿真结果表明，人工神经网络模型优于Ｌｏｇｉｓｔｉｃ模型，可应用于森林资源动态模拟。     

GA-BP神经网络在铜合金海洋腐蚀预测中的应用

目的 充分利用海洋腐蚀数据,深入分析数据规律.方法 在BP神经网络的基础上引入遗传算法,以克服神经网络模型固有缺陷,提高预测精度和训练速度.结果 对GA-BP人工神经网络进行了简要阐述,并以铜合金在海水中的腐蚀数据为例,应用GA-BP人工神经网络建立了海水腐蚀预测模型,对预测结果进行了评价.结论 预测结果表明,模型能满足设计要求,具有较好的泛化能力.     

人工神经网络结构对径流预报精度的影响分析

建立了基于径流形成机理的以时段降水量与前期径流量为预报因子的前向多层人工神经网络径流预报模型；分析了网络结构对月径流预报精度的影响，发现随网络结构的复杂化，网络训练误差减小，模型评定的确定性系数增大，并均趋于稳定，预报检验的确定性系数总趋势是减小；发现影响模型精度的决定因素是网络输入单元数，亦即径流影响因素；提出了以模型评定与预报检验共同高效或等效的模型选择的折衷方法，以及按模型适宜预报域进行多模型组合预报的最佳预报域组合法。     

Differences in Predators of Artificial and Real Songbird Nests: Evidence of Bias in Artificial Nest Studies

Abstract:  In the past two decades, many researchers have used artificial nests to measure relative rates of nest predation. Recent comparisons show that real and artificial nests may not be depredated at the same rates, but no one has examined the mechanisms underlying these patterns. We determined differences in predator-specific predation rates of real and artificial nests. We used video cameras to monitor artificial nests baited with quail and plasticine eggs and Field Sparrow ( Spizella pusilla ) and Indigo Bunting ( Passerina cyanea ) nests in field habitats in central Missouri (U.S.A.). Although daily predation estimates (all predators pooled) were similar between artificial and real nests, predators differed substantially in their depredation of artificial versus real nests. Snakes were the major predator at real nests, and raccoons ( Procyon lotor) were the major predator at artificial nests. We found strong support for models that distinguished predation between two or among three predator groups and between artificial and real nests. There was no snake predation of artificial nests, and the odds of predation of artificial nests was 115–551% (95% confidence interval) and 2–154% of the odds of predation of real nests by mammals and birds, respectively. Artificial nests with plasticine eggs could not be used reliably to identify predators. In several cases plasticine eggs were marked by mice, and raccoons were recorded on video removing the quail egg. Because biases for artificial nests were positive for some predators and negative for other predators (and could be compensating), and potentially existed for all predator groups, conclusions based on artificial nest studies should be suspect even when there is evidence that overall predation rates are similar among real and artificial nests.     

室内空气质量相关标准与评价方法进展

综述了国内外室内空气质量(IAQ)标准、建筑装饰装修材料中有害物质限量标准和室内空气质量评价方法研究的进展情况。根据浓度一呼吸速率一剂量的关系,提出了“参考剂量评价标准”的概念和将来应开展工作的建议。     

运用热脱附/GC/MS分析研究室内空气中TVOC浓度及种类分布

利用热脱附/GC/MS联用技术定性、定量(半定量)分析了多组有代表性的室内空气样品。结果表明,室内空气挥发性有机气体的主要成分是苯系物、烃类、醛酮类、酯类等;装修后3个月内的家居室内空气中的苯25%超标,甲苯58%超标,二甲苯79%超标,TVOC 100%超标;一年后,仅TVOC还有11%的超标。办公室情况类似。