基于社会分层视野下的利益表达问题探析

由于对社会资源占有的不均衡以及利益表达机制的不完善,强势阶层、中间阶层、弱势阶层在利益表达上存在较大差异,强势阶层的利益表达意识和表达机会明显强于其他阶层特别是弱势阶层。这种不合理的利益表达格局会产生一系列消极影响。需要针对不同阶层,完善其利益表达功能,规范利益表达秩序,建立各阶层利益诉求表达的平衡机制。     

温排水对长江安徽段水温的影响模拟

为研究温排水对长江安徽段水温的影响,建立长江干流安庆至芜湖段三维水动力温度输运模型,根据水文实测数据对模型参数进行率定及验证,分别在纵、横断面上预测分析了不利条件下两种排放工况(减排前、减排后)对周边水域温度的影响范围及程度.结果表明:在两种排放工况下,保护目标水温均未受影响;水体温升分布有显著垂向差异,随着水深增加,...     

城中村拆迁对原住民社会阶层变化的影响 ——以武汉市为例

研究目的:基于对武汉市洪山区两个已拆迁城中村原住民的调研数据,分析拆迁对原住民社会阶层变化的影响,为维护社会稳定、缩小贫富差距、完善城中村治理提供基础资料。研究方法:采用潜在类别分析方法在软件LatentGold 4.5中进行客观分层模型和住房分层模型估计,归纳拆迁前后社会客观阶层与住房阶层结构的特征与变化。研究结果:拆迁前社会客观结构为中间大、两头小的"橄榄型",拆迁后中间退休阶层与零工底层群体融合形成新的零工退休阶层,客观社会阶层类别减少,社会分层趋于同质化,阶层分化减弱。拆迁后城中村居民住房的绝对价值均有所提高,住房价值整体的不平等差异减弱,而各个客观阶层内部住房价值的非均衡性均有所增加,阶层间的住房价值差距也随着拆迁而扩大。住房分层与社会客观分层存在较为复杂的关系,前者未打破人们原有的社会客观位置而重构社会阶层,但也并未与客观分层表现为完全的一致性,而是不同客观阶层的住房价值分布特征各不相同。研究结论:未来应重视拆迁对城中村居民的住房财产、社会阶层等各方面的影响,针对城中村社会阶层结构的特征探寻规范化、差别化且能够兼顾效率与公平的拆迁补偿制度,以缓和阶层矛盾。     

Application of GIS modelling to quantify fish habitats in lakes

Quantitative measures of fish habitat in lakes and impoundments have seldom been proposed. The availability of Geographic Information Systems (GIS), however, now provides a means for researchers to assess fish habitat on a whole-lake scale. GIS modelling was used in this study to quantify the impacts of stratification on the amount and distribution of brown trout ( Salmo trutta ) habitat in a large reservoir in Victoria, Australia. Species-specific temperature and dissolved oxygen tolerance ranges for brown trout were applied to the hydrological profile and lake bathymetry. The model predicted that brown trout habitat was reduced by 82% in the summer, and the model was validated with position data from acoustically tagged adult brown trout. This study demonstrated that a quantifiable assessment of fish habitat on a whole-lake spatial scale can be made. It also could be applied to a range of fish species, with applications in ecosystem monitoring and fisheries management.     

引江济汉工程渠道膨胀土分类及工程处理

膨胀土问题是引江济汉工程的关键技术问题之一。在大量的试验分析、研究的基础上,经对比分析,确定适合引江济汉工程区特点的分类指标及分类方法。为适应膨胀土分布不均一的特性,采取"样本1/3"法则对单层土体的膨胀性进行判别及"厚度1/3"法则对渠道膨胀土进行界定。并根据膨胀土的宏观地质特征,进行野外快速判别,以指导工程施工。在此基础上,针对不同膨胀等级的渠段进行可靠、经济合理的工程处理。     

分层型水库取水水温量纲分析及其影响因素研究

水温分层作为影响库区水生生态系统的重要因素逐渐成为研究热点。影响下泄水温的主要因素包括:坝前水温梯度、取水水头、取水流量、取水口宽度、温跃层厚度、重力加速度等。通过量纲分析法,基于π定理尝试建立了溢流式分层取水下泄水温估算模型。采用SAS 9.3统计软件对实验数据进行了回归分析,提出了下泄水温估算方程,相关系数达到95.6%。研究结果表明,水温梯度项为下泄水温估算的最主要因素,其次为取水水头项,最后为流量项;随着坝前水温温跃层强度增大,下泄水温升高,且强度越大,对下泄水温的影响越显著;下泄水温随取水水头的增加而降低,下泄水温降低幅度明显小于取水水头变幅;当取水流量逐渐增大时,下泄水温逐渐升高,但取水流量大于临界值时,下泄水温转而表现出缓慢下降趋势;在本文研究范围内,估算方程可以用于较好地预测下泄水温,预测结果与实验数据的相关系数为99.4%。     

防渗墙作用下堤防保护区地下水动态数值模拟分析Ⅰ：模型、参数及分析方法

 介绍了能够考虑水文气象过程的饱和-非饱和非稳定地下水流运动数学模型。以全封闭和半封闭式防渗墙为重点研究对象，以长江重要堤防为背景概化得到典型二元和多元结构堤基、堤身断面及土层的饱和非饱和渗流参数；以实测资料为基础概化得到较典型的水文气象过程，提出降雨入渗和蒸发排泄边界处理方式以及初始条件确定方法；提出根据二维模型模拟结果用有无对比法分析防渗墙对地下水动态的影响，根据三维模型模拟结果分析防渗墙端部绕渗对地下水流场动态的影响。模型和参数具有典型性，研究方法合理、有效。     

南水北调与黄河未来水量分配

未来南水北调工程的实施,将会置换出一部分黄河水量,这部分水量在流域上中游的再分配将会对整个黄河流域水资源的合理开发利用产生极为深刻的影响。根据黄河流域上中游各省（区）实际情况,在保证经济社会用水和必要的生态环境用水的前提下,运用层次分析和模糊决策理论相结合的方法,对南水北调东线、中线和西线工程不同水平年、不同调水规模情况下,黄河可置换水量在流域上中游的再分配问题进行了探讨。     

基于无人机样方事后分层的作物面积估算

无人机是开展野外调查的一种新型、有效的手段,能够及时、准确地获取地面调查样方信息,为作物面积遥感估算提供精准的样方数据。研究针对无人机抽样调查的样方特点,提出了适合于无人机样方的多层次事后分层指标(多层次-异质性指标、多层次-面积规模指标)。将这些指标分别用于事后分层抽样,估算冬小麦面积。并根据变异系数(coefficient of variance,CV)对其抽样效率进行评价。多层次指标是将多种分层指标分层结果叠加形成的,能够充分反映作物种植空间分布特征、空间异质性及种植规模,可以保证作物种植面积遥感估算的精度。以河南省冬小麦面积估算为例,在冬小麦空间分布空间范围,建立300m×300m抽样框格网,作为抽样基本单元。分别利用实验设计的多层次-面积规模指标、多层次-异质性指标、面积规模指标、异质性指标计算各抽样基本单元的对应指标值。按照累计平方根法计算不同分层指标下的分层界限值。最后进行事后分层估计,计算分层效率,对分层结果与分层效率进行对比分析。计算得到以上4种分层方法的变异系数分别为1.85%、1.41%、2.16%、1.55%。结果表明,结合无人机抽样调查,利用多层次指标法进行分层,各层内作物均质性较好,能够提高农作物面积估算的精度;此外,异质性指标较面积规模指标更能提高分层的层内作物均质性与农作物面积估算精度。     

Stratification regimes and thermodynamic modelling of a subtropical African reservoir

The stratification of a lentic water system is an important factor regulating its biotic activities and processes. The present study investigated changes in temperature and oxygen stratification regimes in Mazvikadei Reservoir 27 years after the first study was conducted during its filling phase. The FLake‐Global model was also tested as a predictive tool for the first time to analyse annual limnological trends in a subtropical reservoir. The lake‐modelling tool FLake‐Global enables an instantaneous estimation of the seasonal cycle of temperature and mixing conditions in shallow freshwater lakes around the world. The results of the present study illustrate that the reservoir was weakly stratified, with the overall thermal stratification patterns somewhat similar to those recorded during the filling phase (1992). The oxygen stratification patterns observed in the present study correspond well to those of thermal stratification. The depth‐integrated oxygen profiles for both the deep and shallow sampling sites exhibited the same pattern, with higher concentrations from July to September. The water column was well oxygenated, indicating the reservoir has matured since its filling phase in 1992, when there was significant hypolimnetic deoxygenation. The FLake‐Global model exhibited good results in predicting annual trends, with the results also indicating no differences in stratification levels in the reservoir for the current and Masundire (1992) filling phase studies. The model predicted lower surface and bottom temperatures, however, compared to those measured in the reservoir. There was lowering of the mixed layer depth from the hot‐wet (November–April) months through the cool‐dry (May–August) season. Latent heat fluxes agreed with the net longwave (LW) predictions for Mazvikadei Reservoir, which exhibited an overall net cooling effect. The stratification has not changed significantly since the previous study in 1988. The FLake‐Global model proved a useful predictive tool when tested in a subtropical system.