转型期西安市产业结构演进分析

选取了12个产业指标,运用区位熵和灰色关联分析相结合的方法测度了西安市各产业的区位优势及产业结构的关联度,分析了转型期西安市产业结构的演进.结果显示,西安市的三次产业结构组合仍需升级优化;在各行业演进中,科技、金融和房地产具有显著的区位优势.此外,通过对各产业发展的相似性测度得出2003年之前就业人员在第一、二产业之间的2-3个产业部门游移,之后从业人员开始在第三产业的一般性服务业(5-7个部门)游移,这显示出第三产业未来巨大的发展潜力与活力.     

Assessment for Salinized Wasteland Expansion and Land Use Change Using GIS and Remote Sensing in the West Part of Northeast China

Due to human impact under climatic variations, western part of Northeast China has suffered substantial land degradation during past decades. This paper presents an integrated study of expansion process of salinized wasteland in Da’an County, a typical salt-affected area in Northeast China, by using Geographic Information Systems (GIS) and remote sensing. The study explores the temporal and spatial characteristics of salinized wasteland expansion from 1954 to 2004, and land use/cover changes during this period. During the past 50 years, the salinized wasteland in study area have increased by 135,995 ha, and in 2004 covers 32.31% of the total area, in the meantime grassland has decreased by 104,697 ha and in 2004 covers only 13.15% of the study area. Grasslands, croplands and swamplands were found the three main land use types converted into salinized wasteland. Land use/cover changes shows that between 1954 and 2004, 48.6% of grasslands, 42.5% of swamplands, and 14.1% of croplands were transformed into salinized wasteland, respectively. Lastly, the major factors influencing salinized wasteland expansion and land use/cover changes were also explored. In general, climatic factors supplied a potential environment for soil salinization. Human-related factors, such as policy, population, overgrazing, and intensified and unreasonable utilization of land and water resources are the main causes of salinized wasteland expansion.     

基于改进YOLOX的变电站工人防护设备检测研究

为解决电气工人防护设备检测问题,通过改进YOLOX算法,提出检测工作人员防护设备的模型。首先在预测部分改进损失函数,为解决损失函数计算存在的缺陷,对IOU损失的计算方法进行改进,根据防护设备任务特性,通过调整各种类型损失函数的权重,增加对模型误判的惩罚,对模型进行优化;其次在算法主干网络中引入CBAM注意力模块提高神经网络对工人防护设备的感知能力;最后在算法Neck部分,将UpSample结构用于多尺度特征融合,加强网络的细节表达能力,从而提升对小目标困难样本的检测精度。研究结果表明：改进后的YOLOX模型平均精度均值达到87.24%,与已有YOLOX模型相比提升2.46%,具备有效性,适用于变电站工人防护设备检测。研究结果可为电气工人提供更高的防护装备检测精度。     

Quantifying and mapping species threat abatement opportunities to support national target setting

The successful implementation of the Convention on Biological Diversity's post-2020 Global Biodiversity Framework will rely on effective translation of targets from global to national level and increased engagement across diverse sectors of society. Species conservation targets require policy support measures that can be applied to a diversity of taxonomic groups, that link action targets to outcome goals, and that can be applied to both global and national data sets to account for national context, which the species threat abatement and restoration (STAR) metric does. To test the flexibility of STAR, we applied the metric to vascular plants listed on national red lists of Brazil, Norway, and South Africa. The STAR metric uses data on species’ extinction risk, distributions, and threats, which we obtained from national red lists to quantify the contribution that threat abatement and habitat restoration activities could make to reducing species’ extinction risk. Across all 3 countries, the greatest opportunity for reducing plant species’ extinction risk was from abating threats from agricultural activities, which could reduce species’ extinction risk by 54% in Norway, 36% in South Africa, and 29% in Brazil. Species extinction risk could be reduced by a further 21% in South Africa by abating threats from invasive species and by 21% in Brazil by abating threats from urban expansion. Even with different approaches to red-listing among countries, the STAR metric yielded informative results that identified where the greatest conservation gains could be made for species through threat-abatement and restoration activities. Quantifiably linking local taxonomic coverage and data collection to global processes with STAR would allow national target setting to align with global targets and enable state and nonstate actors to measure and report on their potential contributions to species conservation.     

铜陵矿区河流沉积物重金属的迁移及环境效应

测定铜陵矿区的新桥至顺安河沉积物中5种重金属的全量和形态,并结合环境条件分析它们的迁移变化特征,以阐明不同重金属对河流沉积物环境影响的程度.结果表明,该区域沉积物重金属除Cr外,Cu、Zn、Pb、Cd的均值皆远超长江下游沉积物背景值,其中以Cu和Cd最显著.重金属横向迁移结果显示,矿山重金属会随着沉积物的距离增加而显著降低,新桥河沉积物的迁移变化显著高于顺安河沉积物.重金属Cu、Zn、Pb、Cr皆以残渣态为优势,Cd则以酸提取态为主;迁移过程中Cu、Zn、Cr残渣态逐步增加,毒性减弱;Pb、Cd的活性态比例增大,仍有较高的释放风险.重金属的纵向迁移结果表明,离矿山的位置远近对沉积柱金属的总量和形态起决定作用;新桥河沉积物金属总量高、活性组分多且垂向变化幅度相对较小,说明尾矿堆积速度较快且释放风险较高;顺安河金属总量较低但垂向变化幅度较大,且多种元素的变化趋势不同,说明矿区下游河流沉积物既受尾矿的影响,也受河流流域物质本身的影响.     

西安城区大气中多氯联苯的气粒分配研究

为了解西安城区大气中多氯联苯(PCBs)的气粒分配规律,于2012年春季对西安城区大气中气态和颗粒态样品进行每周一次的主动采样.结果表明,西安城区大气中PCBs的总浓度(气态和颗粒态)为62.05~454.18pg/m3,主要以气态为主.由Clausius-Clapeyron方程得到的斜率较陡(-5193.24),表明春季大气中的PCBs主要受西安城区附近地面挥发释放的影响.PCBs的气粒分配系数(KP)与过冷饱和蒸汽压(PoL)高度相关,由logKP和logPoL线性回归得到的斜率mr(-0.46~-0.37)均高于平衡状态理论值-1,说明西安城区大气中的PCBs气粒分配尚未达到平衡状态.采用Junge-Pankow吸附模型和Harner-Bidleman吸收模型对PCBs颗粒态百分比(φ)及KP进行了模拟,结果显示两种模型均较好地预测了PCBs的气粒分配行为,但与实验测得的值相比,两种模型均高估了φ值及KP值.     

Agro-biodiversity in rice–wheat-based agroecosystems of eastern Uttar Pradesh,India: implications for conservation and sustainable management

In this study, we analysed the indigenous practices of agro-biodiversity, changing patterns of cropping systems and conservation of agriculturally important natural resources of rice–wheat-based agroecosystems. The research was carried out in three villages of Azamgarh district, eastern Uttar Pradesh, India. Participatory approaches and personal interviews were combined to collect the data from 180 farmers. The results indicated that resource-poor (RP) farmers, by applying traditional practices of natural resource conservation, outperform their rich (RR) counterparts in conserving agro-biodiversity. Increase in irrigation facilities, adoption of improved crop varieties, commercialisation of farming and socio-economic changes have threatened the agro-biodiversity and related natural resources of these agroecosystems. For most of the crops, the RP farmers had better production stability as compared to the RR ones because the former tend to apply more sustainable and ecologically sound indigenous practices. A negative growth rate was observed in the area/numbers and production of legumes, livestock, pasture lands and community forestry. Women, who are the local custodians of conserving indigenous biodiversity (uncultivated species) and crop varieties through localised knowledge and sociocultural institutions, had significantly higher knowledge on agro-biodiversity than men. We concluded that integration of farmers’ eco-friendly practices with formal science and policy-making in a participatory mode may enhance sustainability of functions of agroecosystem leading to the strengthening of adaptive practices in changing climate and socio-economic scenario.     

Post-Sidr public housing assistance in Bangladesh: a case study

Housing is not only a structure, but also a process tied up with social, cultural, psychological and economic attributes. Following Cyclone Sidr, the Government of Bangladesh has been using ‘build back better’ as a colloquial slogan to push forward the idea of resilience in post-disaster interventions, especially with regard to rebuilding houses. This paper examines how and whether the idea is reflected through the government's post-Sidr housing project at Gabtola. It problematizes the slogan from the accounts of community participation, local practicalities, culture, weather and potential future risks. Based on eight months of ethnographic fieldwork at Gabtola, this research found that the basic attributes of the ‘build back better’ slogan are absent with regard to the housing scheme's cost efficiency, management, livelihoods, public health aspects and tolerance against a super-cyclone. These findings will provide valuable insights into the problems associated with the implementation of post-cyclone public housing programmes in Bangladesh. Such insights can assist public authorities and other relevant organizations and donor agencies in revising and improving their post-disaster housing programmes in the wake of future disasters.     

乙醇预发酵对餐厨垃圾与酒糟水解酸化和甲烷发酵的影响

为了解决餐厨垃圾与酒糟干式甲烷发酵过程易酸化问题,考察了两种乙醇预发酵方式-餐厨垃圾单独预发酵和餐厨垃圾与酒糟混合预发酵对底物水解酸化和甲烷发酵的影响,并与不进行乙醇预发酵的对照组比较.结果显示,对照组、餐厨垃圾单独预发酵组(简称“FW预发酵组”)、餐厨垃圾与酒糟混合预发酵组(简称“FW+DG预发酵组”)的甲烷总产率分别为22.8, 222.4, 231.3mL/gVS.乙醇预发酵可以促进发酵底物的水解,预发酵结束后,FW预发酵组发酵底物中的乙醇、总挥发性脂肪酸(TVFA)、乙酸浓度与对照组相比分别提高了4.5、1.4、4.9倍,FW+DG预发酵组则分别提高了7.8、1.6、5.9倍.另外,在甲烷发酵过程中,预发酵组的乙醇浓度显著高于对照组,而乙酸、丙酸和TVFA浓度明显低于对照组,表明乙醇预发酵使有机物更多的转化为乙醇,减少了有机酸的生成,有效缓解甲烷发酵过程中的酸积累、产甲烷受抑制等问题.     

聚集用火下热探测器响应温度的研究

为得出聚集用火下建筑物天花板平面热探测器响应温度的计算公式,采用PyroSim 2015软件进行建模,在模型天花板平面内设置一系列的热电偶代替热探测器监测温度变化,在热释放速率（HRR）分别为1,5,10,20,30 kW和天花板高度分别为3,5,7 m的条件下进行15次数值模拟,对模拟结果数据分析、处理及拟合。研究表明:羽流中心线处温度远高于其他位置;羽流中心线处响应温度随着天花板高度的升高而降低,且与HRR存在显著的二次函数关系;其他位置处响应温度随着天花板高度的升高而降低,随着到羽流中心线距离的增大而降低,且与HRR和到羽流中心线的距离存在显著的二次函数关系。结合室内全年最高温度及补偿温度,建立出聚集用火下热探测器响应温度的计算公式。