基于GA-BP模型的景观小水体富营养化评价方法

为了研究适用于景观小水体富营养化评价的方法,以上海市10个公园景观水体为实验对象,在初步了解了景观小水体水质和营养状况的基础上运用主成份分析法对各项水质指标进行评价因子筛选,并对筛选出来的因子建立富营养化评价等级.运用MATLAB软件的GA-BP算法建立评价模型对10个公园4个季度共40组数据进行评价,结果显示与营养度指数法结果总体一致.选用的Chla, TP, TN, CODMn, SD五个评价因子的数据都比较易得,模型可推广性强.     

Identifying conservation priorities for threatened Eastern Himalayan mammals

To augment mammal conservation in the Eastern Himalayan region, we assessed the resident 255 terrestrial mammal species and identified the 50 most threatened species based on conservation status, endemism, range size, and evolutionary distinctiveness. By using the spatial analysis package letsR and the complementarity core‐area method in the conservation planning software Zonation, we assessed the current efficacy of their protection and identified priority conservation areas by comparing protected areas (PAs), land cover, and global ecoregion 2017 maps at a 100 × 100 m spatial scale. The 50 species that were most threatened, geographically restricted, and evolutionarily distinct faced a greater extinction risk than globally nonthreatened and wide‐ranging species and species with several close relatives. Small, medium‐sized, and data‐deficient species faced extinction from inadequate protection in PAs relative to wide‐ranging charismatic species. There was a mismatch between current PA distribution and priority areas for conservation of the 50 most endangered species. To protect these species, the skewed regional PA distribution would require expansion. Where possible, new PAs and transboundary reserves in the 35 priority areas we identified should be established. There are adequate remaining natural areas in which to expand current Eastern Himalayan PAs. Consolidation and expansion of PAs in the EH requires strengthening national and regional transboundary collaboration, formulating comprehensive regional land‐use plans, diversifying conservation funding, and enhancing information sharing through a consolidated regional database.     

Earthquake-strengthening policy for commercial buildings in small-town New Zealand

New Zealand introduced a seismic retrofitting policy in the wake of the catastrophic Canterbury earthquakes of 2010–11. The aim was to enforce seismic strengthening of earthquake-prone commercial buildings throughout the country. This study focuses on regional urban centres and the economic obstacles to strengthening their aging building stock. In investigating one town, Whanganui, we describe conditions, analyse cases, and identify incentives that apply equally to many other towns in New Zealand. We argue that incentives that suit high-growth, high-value major urban centres are a poor fit for the periphery. Around the world, many places need to upgrade their privately-owned building stock to protect it from disasters, while governments face similar challenges as they struggle to initiate the strengthening of commercial buildings. We analyse the current incentive schemes that aim to support the achievement of policy goals and suggest alternative incentive schemes that can be implemented to improve strengthening outcomes.     

A habitat‐based approach to predict impacts of marine protected areas on fishers

Although marine protected areas can simultaneously contribute to biodiversity conservation and fisheries management, the global network is biased toward particular ecosystem types because they have been established primarily in an ad hoc fashion. The optimization of trade‐offs between biodiversity benefits and socioeconomic values increases success of protected areas and minimizes enforcement costs in the long run, but it is often neglected in marine spatial planning (MSP). Although the acquisition of spatially explicit socioeconomic data is perceived as a costly or secondary step in MSP, it is critical to account for lost opportunities by people whose activities will be restricted, especially fishers. We developed an easily reproduced habitat‐based approach to estimate the spatial distribution of opportunity cost to fishers in data‐poor regions. We assumed the most accessible areas have higher economic and conservation values than less accessible areas and their designation as no‐take zones represents a loss of fishing opportunities. We estimated potential distribution of fishing resources from bathymetric ranges and benthic habitat distribution and the relative importance of the different resources for each port of total catches, revenues, and stakeholder perception. In our model, we combined different cost layers to produce a comprehensive cost layer so that we could evaluate of trade‐offs. Our approach directly supports conservation planning, can be applied generally, and is expected to facilitate stakeholder input and community acceptance of conservation.     

液液小体积萃取气相色谱法测定水中丙烯酰胺

文章建立了溴化衍生-液液小体积萃取-气相色谱法-电子捕获检测器(GC-ECD)测定水中丙烯酰胺的方法。优化了前处理步骤,缩短了样品的处理时间,减少了试剂和样品的使用量。取20 mL水样,分别加入H2SO4、KBrO3、KBr,4℃下反应至少30 min,丙烯酰胺与新生溴反应生成2,3-二溴丙酰胺。加入Na2S2O3去除多余的溴,加无水硫酸钠于室温下溶解盐析,用2.0 mL乙酸乙酯萃取,取上层萃取液GC-ECD分析。用衍生物2,3-二溴丙酰胺的响应峰面积对水中丙烯酰胺的质量浓度绘制工作曲线,相关系数达到0.999 47。方法适用于饮用水、地表水中丙烯酰胺的测定,检出限可达到0.026μg/L,相对标准偏差RSD为2.70%,加标回收率为80.67%¹00.43%。     

玉溪尖山河小流域N的输出特点研究

对澄江尖山河小流域不同土地利用类型径流小区进行监测,并对地表径流中氮素的流失特征进行研究。结果表明：随着降雨量的不断增大,径流中的总氮和氨氮的输出浓度也有上升的趋势;在相同降雨条件下,各地类年平均总氮输出浓度为：农地7．955mg／L、人工林7．4886mg／L、次生林6．9836mg／L、灌草丛4．5188mg／L;氨氮的年平均输出浓度为：农地0．8474mg／L、人工林0．7286mg／L、次生林0．6514mg／L、灌草丛0．4782mg／L。农地的总氮输出浓度和氨氮输出浓度最大,人工林次之,灌草丛和次生林较小。研究结果表明,灌草丛和次生林较高的植物覆盖有效地保持了水分和土壤,从而也减缓了氮素的输出。     

喀斯特小流域土壤有机碳分布特征及其影响因素

为阐明喀斯特小流域土壤有机碳含量分布格局及其主要影响因素,采用野外布点采样、实验室测定相结合的方法,利用后寨河流域2755个详细调查的剖面信息,定量研究了土壤有机碳含量的分布特征,并利用主成分分析法分析了影响后寨河流域土壤有机碳含量的主要因子。结果表明,流域内土壤有机碳含量高、变异性强。流域表层土壤有机碳平均含量为25.07g/kg,变幅为1.61~119.11g/kg。全流域整个剖面土壤有机碳平均含量为20.71g/kg,土壤有机碳含量变异系数变幅为52.68%~75.28%,呈中等强度变异;流域土壤有机碳含量处于较高的水平,91.7%的样点表层土壤有机碳含量高于11.6g/kg;石砾含量与土壤有机碳含量性关系不显著,土壤有机碳含量与坡度、海拔、岩石裸露率均呈极显著正相关关系,与容重呈显著负相关关系;主成分分析结果表明,海拔、坡度、土壤类型是影响后寨河流域土壤有机碳分布的主导因子,在土壤有机碳储量估算时必须高度重视。     

中国小流域山洪灾害防御研究

文章主要研究中国小流域山洪灾害防御研究,利用文献调查法和综合分析法,分别从中国山洪灾害造成概况、特点与危害、诱因与影响因素、主要表现形式以及防御措施几个方面进行研究.结果表明:首先研究小流域山洪灾害的特点、影响因素及其诱因对于制定具有针对性的防御措施至关重要;其次科学合理的山洪灾害应对措施能够极大的降低山洪灾害造成的损失;最后制定科学合理的山洪灾害预案、恢复生态平衡、加强小流域综合治理是防御山洪灾害的有效途径.     

中小型企业员工不安全行为管理模式构建研究

为解决我国中小企业员工不安全行为管控难题,基于不安全行为管理的重要性,采用文献分析法、现场调研法,调查了绵阳市130余家中小型企业不安全行为管理现状,分析得出中小型企业不安全行为管理存在的问题。基于协同理论,研究了安全文化、BBS行为观察流程和杜邦安全训练观察计划3种不安全行为管理模式并对其要素进行组合优化,提出了适合我国中小型企业的不安全行为管理模式。结果表明:不安全行为协和管理模式有利于解决纠正员工不安全行为,提升员工安全作业水平。     

小曲率轿车覆盖件拉深模设计

在分析小曲率轿车覆盖件成形特点的基础上,指出采用阶梯拉深是提高材料塑性变形、减少回弹的有效措施,以一个典型零件前盖外板为例,设计了其拉深工艺补充面,并给出了有限元模拟结果以验证有效性。