生态安全弹性与生态安全"倒U"曲线

文章从生态安全的研究现状入手,根据生态系统和人类社会系统之间的主要关系,论述了生态安全弹性和安全"倒U"曲线理论.生态安全弹性能够反映安全系数、安全阈值、干扰程度三者的关系,由它来判断人类向生态系统索取自然资源的活动更具有预测性、可操作性,并能保证生态系统自身也处于可持续发展的良性状态.     

蔬菜施用环保液体有机肥的效果

城市餐饮垃圾经发酵处理生成的环保液体有机肥,在蔬菜上使用效果显著,菜心增产比常规施肥增产22.5%~26.3%,青瓜增产5.0%~15.0%。环保液体有机肥可以替代常规肥料作蔬菜的追肥。     

兔子宫内膜蛋白等电聚焦电泳载体两性电解质pH范围及比例的选择

兔子宫内膜蛋白是研究早期胚胎发育过程中胚泡附植机制的关键因素之一．为了对子宫内膜蛋白进行有效的分离，本研究探讨了用于等电聚焦电泳的载体两性电解质pH范围及其比例．研究结果表明：在只有pH3～9．5的情况下，蛋白质谱带主要分布于胶条碱性端1／3区域，酸性端无谱带；在载体两性电解质pH3-9．5：pH4～6=1：4的情况下，蛋白质谱带主要分布于胶条碱性端2／3部分；在载体两性电解质以pH3-9．5：pH4～6：pH6—9=1：4：1时，蛋白质谱带分布比较均匀，酸性端也有谱带分布．这说明在作子宫内膜蛋白的等电聚焦电泳时采用pH3～9．5：pH4～6：pH6～9=1：4：1比较理想．     

气相色谱法快速测定蔬菜中灭杀毙

用蒸馏水一次提取新鲜蔬菜样品，以SE－30和QF－1为固定液，Chromosorb W AW DMCS为固定相，2m填充柱分离，氢火焰检测器检测，进样10uL测定灭杀毙含量，以保留时间定性，外标法定量，分析时间小于150s，方法回收率95．4％，相对标准差3．6％，可用作上市蔬菜灭杀毙农药残留量的快速测定。     

氢自养还原菌同步去除水中Cr(Ⅵ)和NO3-

本实验研究了序批式条件下Cr（Ⅵ）和NO₃^-浓度、pH值和H₂含量对于氢自养还原菌同步去除水中Cr（Ⅵ）和NO₃^-的性能及微生物群落的影响.结果表明：系统中存在氢气时,正常活性的氢自养还原菌可实现Cr（Ⅵ）的还原;Cr（Ⅵ）初始浓度不高于2000 μg/L时,Cr（Ⅵ）和NO₃^-的还原速率及氢自养还原菌的活性不会受到Cr（Ⅵ）初始浓度的影响;作为一种优先电子受体,NO₃^-会与Cr（Ⅵ）争夺电子,降低Cr（Ⅵ）的还原速率;氢自养还原菌同步还原Cr（Ⅵ）和NO₃^-的最佳pH值为7.0左右,酸性或碱性环境都会抑制Cr（Ⅵ）还原,且NO₂^-会随着pH值的升高逐渐积累;作为电子供体,H₂是还原Cr（Ⅵ）和NO₃^-的必要条件,但H₂足量后,过量提供H₂不能提高Cr（Ⅵ）和NO₃^-的还原速率.     

考虑尾矿材料参数空间变异性的尾矿坝稳定可靠度分析

为客观地评价尾矿坝稳定性,在随机场理论和极限平衡分析框架下,采用考虑参数空间变异性尾矿坝可靠度分析的非侵入式随机有限元法,通过Karhunen Loève级数展开方法离散尾矿材料参数（渗透系数、摩擦角等）随机场,利用Hermite随机多项式展开拟合尾矿坝安全系数与输入参数之间的隐式函数关系;再采用拉丁超立方抽样技术产生输入参数样本点求解多项式展开系数;最后,通过应用到一实际尾矿坝工程说明了该方法的有效性。结果表明,该方法可以真实地模拟尾矿材料的空间变异性对尾矿坝稳定性的影响,保证尾矿坝可靠度分析与确定性稳定分析互不耦合,与10 000次直接拉丁超立方抽样方法相比,该方法具有较高的计算精度和效率。     

压裂返排液循环使用技术综述

综述了传统处理方法和深度处理方法两大类压裂返排液处理方法的特点和处理效率。介绍了对氧化破胶的压裂返排液和非氧化破胶的压裂返排液进行处理的方法和机理,以及返排液循环使用效果和性能检测的标准。指出研发含有高分子聚合物稠化剂的返排液循环使用工艺、高效便捷的压裂返排液循环使用工艺和新型可循环使用的压裂液体系等将是未来压裂返排液循环使用的发展方向。     

再加热步进炉仪表系统自动化节能改造

本文描述了采用SIEMENS S7 414-5H CPU和WINCC等自动化产品实现再加热步进炉的自动控制。网络拓扑结合了Profibus-DP冗余现场总线和以太网(TCP/IP),使用STEP7编程实现了双交叉PID,使用WINCC软件实现了各工艺子系统画面以及参数监控、报表打印等功能。实现了用户控温节能的目的。     

Contributions of paraecologists and parataxonomists to research,conservation, and social development

Citizen science has been gaining momentum in the United States and Europe, where citizens are literate and often interested in science. However, in developing countries, which have a dire need for environmental data, such programs are slow to emerge, despite the large and untapped human resources in close proximity to areas of high biodiversity and poorly known floras and faunas. Thus, we propose that the parataxonomist and paraecologist approach, which originates from citizen‐based science, is well suited to rural areas in developing countries. Being a paraecologist or a parataxonomist is a vocation and entails full‐time employment underpinned by extensive training, whereas citizen science involves the temporary engagement of volunteers. Both approaches have their merits depending on the context and objectives of the research. We examined 4 ongoing paraecologist or parataxonomist programs in Costa Rica, India, Papua New Guinea, and southern Africa and compared their origins, long‐term objectives, implementation strategies, activities, key challenges, achievements, and implications for resident communities. The programs supported ongoing research on biodiversity assessment, monitoring, and management, and participants engaged in non‐academic capacity development in these fields. The programs in Southern Africa related to specific projects, whereas the programs in Costa Rica, India, and Papua New Guinea were designed for the long term, provided sufficient funding was available. The main focus of the paraecologists’ and parataxonomists’ activities ranged from collection and processing of specimens (Costa Rica and Papua New Guinea) or of socioeconomic and natural science data (India and Southern Africa) to communication between scientists and residents (India and Southern Africa). As members of both the local land user and research communities, paraecologists and parataxonomists can greatly improve the flow of biodiversity information to all users, from local stakeholders to international academia.     

Limitations of Gravity Models in Predicting the Spread of Eurasian Watermilfoil

Abstract: The effects of non‐native invasive species are costly and environmentally damaging, and resources to slow their spread and reduce their effects are scarce. Models that accurately predict where new invasions will occur could guide the efficient allocation of resources to slow colonization. We assessed the accuracy of a model that predicts the probability of colonization of lakes in Wisconsin by Eurasian watermilfoil (Myriophyllum spicatum). We based this predictive model on 9 years (1990–1999) of sequence data of milfoil colonization of lakes larger than 25 ha (n =1803). We used milfoil colonization sequence data from 2000 to 2006 to test whether the model accurately predicted the number of lakes that actually were colonized from among the 200 lakes identified as being most likely to be colonized. We found that a lake's predicted probability of colonization was not correlated with whether a lake actually was colonized. Given the low predictability of colonization of specific lakes, we compared the efficacy of preventing milfoil from leaving occupied sites, which does not require predicting colonization probability, with protecting vacant sites from being colonized, which does require predicting colonization probability. Preventing organisms from leaving colonized sites reduced the likelihood of spread more than protecting vacant sites. Although we focused on the spread of a single species in a particular region, our results show the shortcomings of gravity models in predicting the spread of numerous non‐native species to a variety of locations via a wide range of vectors.