东部平原矿区复垦土壤微生物群落特征及其组装过程

复垦对恢复矿区土壤生产力极为重要,但复垦土壤生产力重建的微生物学机制尚不清晰.为此,采集复垦8 a、复垦11 a、复垦14 a和复垦17 a这4个复垦时长和1个未复垦对照共75个表层土样进行16S rRNA扩增子高通量测序,分析微生物群落组成、潜在功能及其组装机制.结果表明：(1)群落丰富度随复垦时间增加而增加,且高于对照样.但群落多样性和均匀度却随复垦时间增加而降低(P<0.05);(2)复垦土壤中酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)、变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)占主导地位,且前两者相对丰度显著高于对照样(P<0.05),后两者则相反(P<0.05);(3)复垦土壤中辅酶转运与代谢、翻译、核糖体结构与生物发生等8种功能呈正向演替,随复垦时长不断增强;(4)平原矿区微生物群落生态网络模块性良好,且关键类群多属酸杆菌门和拟杆菌门.群落组装以确定性过程为主导,同质性选择贡献最大,主要受当地特殊环境操控.这些发现为改善复垦土壤生产力和生态服务提供了理论依据.     

Assessing Spatial Scale Effects on Hydrometric Network Design Using Entropy and Multi‐objective Methods

In order to facilitate water resources decisions, it is important that accurate and informative hydrometric data are collected. Combining information theory with multi‐objective optimization has led to methods of optimizing the information content provided by hydrometric networks; however, there is no available study on the effects of spatial scale and data limitation on these methods. Herein, a dual entropy multi‐objective optimization (DEMO) and a transinformation (TI) analysis were done to recommend optimal locations for additional hydrometric stations in the Madawaska Watershed. This analysis was designed to be comparative to a similar study conducted on the Ottawa River Basin which encompasses the Madawaska Watershed to allow for an investigation of the spatial scale effects in this type of network design. This study concludes that TI analysis is not adversely affected by scaling; however, the DEMO analysis is sensitive to the placement of potential station locations and the size of the study area. This study also examines the benefit of including nearby stations when the area of interest does not have a sufficient number of existing hydrometric stations for analysis. It is shown that these stations can provide useful information because their inclusion in the analysis increased the average TI in the watershed. Recommendations were made as to the ideal locations of additional stations in the Madawaska Watershed hydrometric network.     

Les Reciproqueteurs: post-regulatory corporatism

ABSTRACT

Reflexive governance can be understood as an emergent encapsulated trust-building corporatism where network participants are neither state functionaries nor market entrepreneurs but network reciproqueteurs. This paper argues that such reflexive network governance results in a post-regulatory corporatism (PRC)—a more adaptable, less formalized, and flexible mode of interest intermediation, policy-making, and policy-implementation than previous modes of corporatist intermediation. Functional differentiation processes engender ‘negotiated connected contracts' in rescaled space in between inter-regional assemblages, a mode of structurally coupling new social partners in the emergent transnational knowledge-based economy. This involves the building of new social capital of network trust-building manifested in the norms of reciprocity and reflexive law constituted as a new mode of protocolism: one associated with the social learning and policy designing necessary for ecological systems' autopoeisis, resilience, and sustainability. This paper conceptualizes reflexive network governance as protocolism in constellations of PRC and discusses examples from the area of environmental policy-making. PRC is understood as a new mode of negotiated rule-making: as a recursive protocolism of multi-stakeholder social pacts constituted by frame agreements and negotiated connected network contracts.     

Is Learning without teaching possible? The productive tension between network governance and reflexivity

ABSTRACT

Theories of reflexive governance are closely linked with the claim that more traditional modes of coordination have been replaced by networked structures, allowing reflexivity to emerge and reflexive learning to function as a steering mechanism in rapidly changing policy contexts. This paper explores this connection between reflexivity, governance, learning and networks in societal transitions, focusing particularly on the claim that networks will deliver reflexive learning. Using network theories from both policy networks and network governance and a case study of the Canadian agricultural biotechnology (agbiotech) policy network, it suggests that the kind of learning produced in networks will be a function of network structure. In particular, higher order reflexive learning will be compromised by the inevitability of the political struggle for nodality or central place in networks and the ensuing distribution of opportunities for bridging and bonding activities. Networks such as the Canadian agbiotech policy network that may promote learning but not necessarily reflexive learning are increasingly disadvantaged in contemporary policy settings.     

Design and optimization of new La1−xCexNi1−yFeyO3 (x,y = 0–0.4) nano catalysts in dry reforming of methane

The paper reports the production of syngas from dry reforming of methane (DRM) over La_1?xCe_xNi_1?yFe_yO₃ (x, y = 0–0.4) perovskites. A series of La_1?xCe_xNi_1?yFe_yO₃ were designed by central composite design (CCD) and synthesized by a sol–gel auto combustion method. Artificial neural network (ANN) approach was used to determine the relationship between preparation and operational parameters on the performance of the catalysts in the DRM process. Nickel mole fraction, lanthanum mole fraction, calcination temperature, and reaction temperature were considered as input variables, and conversion of methane was considered as the output variable. An ANN model with nine neurons in the hidden layer was the suitable in predicting conversion of methane. The genetic algorithm (GA) was subsequently used to determine the optimal preparation condition for enhancing the conversion of methane. La_0.6Ce_0.4Ni_0.99Fe_0.01O₃ catalyst, calcined at 756°C was obtained to be the most active catalyst owing to the optimal composition of nickel and lanthanum in the catalyst formulation.     

基于步降应力加速贮存试验的电缆网贮存寿命评估

目的针对某型电缆网开展加速贮存试验设计,并通过试验预测产品贮存寿命。方法基于步降应力加速贮存试验方法,结合Arrhenius模型,利用对数正态分布的极大似然估计法,对试验结果进行评估。结果根据加速贮存试验结果,在较短时间内评估得到电缆网的贮存寿命,评估得到电缆网在25℃下的平均寿命点估计值在20年以上,并获得其加速模型和加速因子。结论为电缆网贮存寿命的定量评估提供了一种参考方法,为武器装备延寿整修提供依据。     

海南岛潜在震源区的研究

本文应用人工神经网络原理,以地震构造和地震活动性为主要特征,对我国海南岛进行了潜在震源区的定量划分。这种划分既反映了当前人们对地震发生规律的认识水平,又为城建部门按照工程重要性和使用年限选取相应的抗震设计参数提供了依据。     

基于BP神经网络与马尔可夫链的污水处理厂脱氮效果模拟预测

在实际污水处理厂运行过程中,其最终出水水质会受多种因素影响制约,而基于生物反应机理的活性污泥数学模型(ASM)并未将这些生物反应以外的因素考虑在内,由此带来一些不足.对此,本文提出可通过基于数据挖掘技术的黑箱模型对污水厂处理效果进行模拟预测.结合具体实际分析,提出可将BP神经网络与马尔可夫链组合应用于污水处理脱氮效果预测中.首先,通过BP神经网络模型对北京某大型污水处理厂实际进出水数据和工艺参数进行粗略拟合;其次,利用马尔可夫链对拟合结果及误差进行状态划分以进一步提高预测精确度;最后,运用基于BP神经网络与马尔可夫链的组合模型预测分析了该厂的实际出水水质.试验结果表明,BP神经网络适用于污水处理脱氮过程的拟合计算,而通过与马尔可夫链组合,可以提高模拟预测的精度和可靠性.     

氮气中1,3-丁二烯气体标准样品的研制

采用重量法对氮气中1,3 -丁二烯气体标准样品的制备方法进行了研究.依据国际标准化组织(ISO)颁布的“6142气体分析-校准气体混合物的制备-重量法”的标准方法,对标准气体在重量法制备过程中的定值分析、不确定度来源、不确定度估算以及不确定度合成进行了阐述.制备的1,3 -丁二烯气体标准样品量值与同类标准样品量值具有可比性,能够满足环境有机污染物监测工作的需要.     

苏州水网地区河道底泥的重金属分布特征与污染风险

苏州100 km²水网地区采样点的底泥中重金属Cd、 Cu、 Cr、 As、 Ni、 Pb和Zn含量的平均值分别为1.4、127.4、83.2、18.2、51.7、145.1和350.7 mg·kg^-1,分别是背景值的13.7、5.7、1.1、1.7、1.9、5.5和5.6倍,超过GB 15618-2018标准风险筛选值的点位比例分别为100.0%、97.3%、38.4%、83.6%、97.3%、90.4%和100.0%.采用改进的地累积指数法评价单种重金属元素的污染程度,可知苏州水网地区底泥中7种重金属元素污染程度依次为：Cd>Cu>Pb>Zn>As>Cr>Ni,其中,Cd属于极强污染,Cu和Pb属于强度到极强污染,Zn属于强度污染,As属于中度到强度污染,Cr和Ni属于中度污染.古城区、西北部、西南部和东部底泥样品中Cd、 Pb、 Cu和Zn均是高污染贡献的重金属元素,重金属潜在生态风险程度从大到小依次为：西北部、西南部、古城区和东部.相关性分析和主成分分析表明,Cd、 Cu、 Cr、 As、 Ni、 ...