企业与消费者型(B to C)网络支付模式及相关安全技术研究

随着电子商务的飞速发展,网络支付模式及安全问题已经成为制约其发展的瓶颈。根据企业与消费者型(Bto C)电子商务网络支付系统的一般模式,较为详细地研究了各种Bto C型电子商务网络支付模式的类型,依据Bto C型电子商务网络支付系统所受不同类型攻击,系统地分析了Bto C型电子商务网络支付所面临的安全问题,并对其相关安全技术的实现进行了较为系统的研究和分析,最后根据Bto C型网络安全支付协议发展过程和存在问题,分析了一个基于3D-Secure的Bto C型网络安全支付模式实现过程。     

无线传感器网络(WSNs)路由安全问题的现状与对策研究

笔者对比分析了无线传感器网络(WSNs)安全体系结构的组成;讨论了限制无线传感器网络安全的各种因素以及安全评估的目标;在分析现有路由协议的基础上,从路由安全的攻防角度入手,详细阐述了现有各种路由攻击手段的原理、特点及危害,并给出了相应的攻击示意框图;有针对性地提出一些相应的安全防范对策,为WSNs安全路由的设计与实现提供了一些思路。     

基于铀尾矿库核素污染监测WSN分簇路由协议

用WSN对铀尾矿库核素污染监测优于传统有线布置,为解决无线传输路由能耗的问题,提出了一种基于蚁群算法的前向传输分簇路由协议。该协议以分簇的方式来减少数据发送量与寻优开销,在下一跳接收节点选择阶段,以前向传输区域为切入点,利用优化的蚁群算法进行多路径搜索最后选出满足条件的最优路径。仿真实验表明,CFTA协议的网络生存周期有效延长,并减小了能耗。     

铅锌矿区废弃地修复客土层的重金属污染特征分析

采集湖南郴州某典型铅锌矿区废弃地植物修复客土层（0~30 cm）及污染土层（30~50 cm）土壤,测定土壤中Cd、Cr、Cr⁶⁺、Cu、Ni、Pb、As和Hg的含量;采用地累积指数法、内梅罗指数法和潜在生态风险指数法对土壤中重金属的含量及污染程度进行定量评价;并通过BCR连续分级提取法分析重金属的形态.结果表明,客土的As含量以及污染土的Pb和As含量均远超出"土壤环境质量建设用地土壤污染风险管控标准（试行）-GB36600—2018"中第二类用地筛选值.对重金属含量和污染程度的评价结果表明,试验土壤主要以Pb和As污染为主,污染土中Cd、Cu、Pb和As的污染程度均高于客土.土壤中Cd和As的生态风险系数较高,最高分别达到了22.96和568.57.Cd和As是研究区域中土壤重金属潜在生态风险的主要贡献者;BCR结果表明,Cd在客土和污染土中均具有最高的生物有效性,酸可溶态Cd的最高占比达到31.9%.污染土和客土之间的混掺,污染土中活性金属向客土层的迁移以及植物根系分泌物的螯合作用都是导致客土层土壤中重金属总量和生物有效性增加的原因.本研究结果可为铅锌矿区废弃地重金属污染治理提供参考.     

Carbon benefits from Amazonian forest reserves: leakage accounting and the value of time

Amazonian forest reserves have significant carbon benefits, but the methodology used for accounting for these benefits will be critical in determining whether the powerful economic force represented by mitigation efforts to slow global warming will be applied to creating these reserves. Opportunities for reserve creation are quickly being lost as new areas are opened to deforestation though highway construction and other developments. Leakage, or the effects that a reserve or other mitigation project provokes outside of the project boundaries, is critical to a proper accounting of net carbon benefits. Protected areas in the Amazon have particularly great potential mitigation benefits over an extended time horizon. Over a 100-year time frame, virtually no unprotected forest is likely to remain, meaning that potential leakages (both leakage to the vicinity of the reserves and that displaced by removing protected areas from the land-grabbing market) should not matter much because any short-term leakage would be “recovered” eventually. The effect of the value attributed to time greatly influences the impact of leakage on benefits credited to reserves. Simple assumptions regarding leakage scenarios illustrate the benefits of reserves and the critical areas where agreement is necessary to make this option a practical component of mitigation efforts. The stakes are too high to allow further delays in reaching agreement on these issues.     

改进BCR提取法对山东荣成天鹅湖金属环境赋存研究

采用改进的BCR提取法,分析2009年11月采集的山东荣成天鹅湖表层沉积物中Cu、Pb、Zn、Cr的环境赋存(酸可溶态、可还原态、可氧化态及残渣态);以污染系数法(CF)和次生相原生相分布比值法(RSP)对金属外源输入影响以及潜在的生物危害进行了分析。结果表明:Cu以可还原态和残渣态为主,各站位的潜在生物危害有差异;Pb的醋酸可提取态与可还原态达60.8%,生物可利用性强,具有较高的潜在生态危害;Zn和Cr主要以稳定的残渣态(分别为64.3%和57.1%)形式存在,同时受外源输入的影响也较轻微(CF<1),因而不具有环境危害。     

钡盐厂周边土壤中钡及各形态钡的分布规律

贵州省天柱县某钡盐厂污染排放导致周边土壤遭受污染,为此对钡盐厂周边污染土壤进行采样分析。分析结果表明,钡盐厂周边土壤存在严重的钡富集,钡盐厂周边2km范围内土壤钡的浓度范围为760.4～3196mg.kg-1;污染区土壤表层钡的分布受污染源的距离关系及所在风向的控制,各形态钡占总钡平均比例大小关系为残渣态>Fe/Mn结合态>有机结合态>弱酸结合态;土壤剖面钡的分布规律为表层土壤中的总钡及各形态钡的含量远高于下层,总体呈垂直递减规律;钡及形态钡在土壤中的迁移转化规律受土壤pH、电导率、有机质、总氮以及碱解氮等诸多因素的影响。     

雅鲁藏布江中段表层沉积物重金属形态分布及风险评价

采用了欧共体BCR分步提取的方法,对西藏雅鲁藏布江中段人口密集区的表层沉积物中的9种重金属元素(Cd、Co、Ni、Cu、Zn、Pb、Cs、As和Cr)不同赋存形态进行了研究,分析了其形态分布特征.并分别用风险评价编码法(RAC)和沉积物质量基准系数法(SQG-Q)对沉积物重金属生物有效性进行了风险评价.结果表明:1元素Cr、As主要赋存于残渣态(占87%~96%),Ni、Cu、Co和Cs赋存特征较为相似,来自非残渣态约占20%,元素Cd酸可提取态和可还原态约占65%,表现出较高的生物毒性;2由RAC评估得出元素Cd有效态占37.38%,对环境构成高风险等级,元素Co、Ni、Cu和Zn对环境的危害处于低风险状态,元素Pb、Cs、As和Cr处于无风险状态,单从重金属形态的生物有效性评价,雅江沉积物对环境构成的风险排序为Cd>Co>Ni>Cu>Zn>Pb>Cs>As>Cr;3沉积物SQG-Q系数为0.804,具有中度的潜在生物毒性效应,鉴于该研究重金属元素主要赋存于残渣态,并且重金属平均含量除元素Cr和Ni外,其余元素均小于TEL和PEL值,所以,该河段总体上处于较低的风险等级,受到人为污染活动较少,污染程度较低.     

Can the envisaged reductions of fossil fuel CO<Subscript>2</Subscript> emissions be detected by atmospheric observations?

The lower troposphere is an excellent receptacle, which integrates anthropogenic greenhouse gases emissions over large areas. Therefore, atmospheric concentration observations over populated regions would provide the ultimate proof if sustained emissions changes have occurred. The most important anthropogenic greenhouse gas, carbon dioxide (CO(2)), also shows large natural concentration variations, which need to be disentangled from anthropogenic signals to assess changes in associated emissions. This is in principle possible for the fossil fuel CO(2) component (FFCO(2)) by high-precision radiocarbon ((14)C) analyses because FFCO(2) is free of radiocarbon. Long-term observations of (14)CO(2) conducted at two sites in south-western Germany do not yet reveal any significant trends in the regional fossil fuel CO(2) component. We rather observe strong inter-annual variations, which are largely imprinted by changes of atmospheric transport as supported by dedicated transport model simulations of fossil fuel CO(2). In this paper, we show that, depending on the remoteness of the site, changes of about 7-26% in fossil fuel emissions in respective catchment areas could be detected with confidence by high-precision atmospheric (14)CO(2) measurements when comparing 5-year averages if these inter-annual variations were taken into account. This perspective constitutes the urgently needed tool for validation of fossil fuel CO(2) emissions changes in the framework of the Kyoto protocol and successive climate initiatives.     

《京都议定书》生效给林区经济发展带来新机遇——碳汇的利用途径与前景

<京都议定书>生效.它的实质是保护人类生存环境和地球生态平衡.清洁发展机制CDM是在<京都议定书>中建立的一个国际合作机制,清洁发展机制造林、再造林项目是利用森林的固碳生态功能,削减部分大气中CO2含量,研究CDM机制对于发展林区经济可持续发展具有重要意义.