基于集体记忆的红色旅游地地方性建构

红色历史的集体记忆嵌入动态的地方建构和空间生产过程,成为地方性重构的有力素材。文章以云南省宾川县新庄红军村为例,通过参与式观察和访谈文本分析等质性方法,从地方性景观与话语的再建构,以及地方性情境创设的空间实践,探讨新庄村的地方性建构机制。研究发现：具体的地方要素在地方-记忆的互动关系中起中介承启作用。地方要素既促进红色旅游情境下记忆的唤起、存储与再创造,又对集体记忆重新建构的地方特质、意义与场所精神进行地方性元素表达。旅游情境创设与地方性展演使集体记忆不断得到投影、表达与重构,推动差异化的地方叙述与体验。     

大连市大气污染物质量浓度与气溶胶光学厚度的相关性分析

分别对2015年6~12月和2016年6~12月大连地区的大气污染物PM2.5、PM10、SO₂、NO₂、CO和O₃的浓度数据进行数据统计分析,基于ENVI软件平台利用MODIS数据反演大连地区的气溶胶光学厚度,通过回归建模研究气溶胶光学厚度与大连地区10个地面监测站点的大气污染物PM2.5、PM10、SO₂、NO₂、CO和O₃的浓度数据的相关性。回归建模以气溶胶光学厚度（AOD）为自变量,以大气污染物PM2.5、PM10、SO₂、NO₂、CO和O₃为因变量,在SPSS软件中分别选取线性、对数、三次、乘幂、指数5种函数类型进行研究,通过对比回归模型的拟合优度R²,选择最优拟合模型,探讨利用遥感数据反演气溶胶光学厚度监测大气污染的相关性。结果表明：气溶胶光学厚度与NO₂、PM2.5和PM10的最优拟合模型均为三次模型,其拟合优度R²分别是0.685、0.801和0.845;与O₃和SO₂的最优拟合模型为指数模型,其R²为0.367和0.482;与CO的最优拟合模型为对数模型,其拟合优度R²为0.810。该结果为分析大气气溶胶污染来源以及治理提供了数据。     

内陆水体好氧甲烷氧化过程研究进展

内陆水体是全球碳循环的关键组成部分,是大气中甲烷(CH4)的重要来源,每年从内陆淡水与自然湿地排放进入大气的CH4约为185～357 Tg/a.通常,内陆水体中CH4主要由分布于水层底部的厌氧区或沉积层内的产甲烷菌介导产生,其向水层表面传输的过程中易被甲烷氧化菌所氧化.甲烷氧化菌可分为好氧甲烷氧化菌和厌氧甲烷氧化菌,有...     

万象盆地不同成钾区的水不溶矿物对比及其指示意义

老挝万象盆地属于沙空那空盆地的次级盆地,沉积了厚层的钾石盐矿,而钾石盐中还存在着部分水不溶物,通过研究不同成钾区域的钻孔发现:水不溶物主要包括硬石膏、方硼石、白云母、石英、水氯硼钙石、碳酸盐矿物以及零散的黄铁矿,通过水不溶矿物在钻孔中的分布及组合特征发现,钾盐从析出到结束,水不溶物出现规律性特征:钾石盐含量越多方硼石含量也越多,而硬石膏且越少,并在钾石盐高峰期出现鲕粒方硼石,鲕粒方硼石分布表明成钾晚期沉积环境为动荡的浅水环境。水不溶矿物组合、形貌特征及硼同位素分析研究显示,在万象盆地成钾阶段,钾盐沉积不是一成不变的而是具有明显的阶段性,其过程可以分为石盐沉积晚期,钾盐沉积早期,钾盐沉积中期和钾盐沉积晚期等4个不同阶段,其中钾盐阶段中期为钾盐沉积高峰期。因此,水不溶物研究能够很好地反演钾盐沉积环境,可作为古蒸发岩沉积研究的重要指标。     

桂中都安-马山煌斑岩成因及其构造意义

为精确厘定桂中地区都安-马山带煌斑岩的形成时代并探讨其源区属性、构造环境及其动力学背景,对其进行了LAICP-MS锆石U-Pb定年、⁴⁰Ar-³⁹Ar金云母定年、Hf同位素分析测试和全岩地球化学研究.结果表明,锆石U-Pb定年未能成功限定煌斑岩的成岩年龄,但煌斑岩中发育大量2 578～1 650 Ma的捕获锆石,指示其存在太古宙-古元古代变质基底.金云母⁴⁰Ar-³⁹Ar定年结果限定了煌斑岩的侵位年龄为100.4±0.99 Ma.Hf同位素研究表明,ε_Hf(t)有正有负,且正值多于负值,表明岩浆源区主要以新生地壳为主,存在部分古老地壳的再循环.全岩地球化学分析显示,煌斑岩具有较低的SiO₂含量(47.66%～50.93%)及高的K₂O含量(4.98%～6.77%)、富集LILE和LREE而亏损HFSE(如Nb、Ta和Ti),表现出富集地幔和俯冲流体交代作用的特征.桂中煌斑岩形成过程中,地壳混染作用十分有限,主要形成过程为:流体交代的富...     

A hybrid ensemble method for improved prediction of slope stability

Accurate prediction of slope stability is a significant issue in geomechanics with many artificial intelligence (AI) techniques being utilised. However, the application of AI has not reached its full potential because of the lack of more robust algorithms. In this paper, we proposed a hybrid ensemble method for the improved prediction of slope stability using classifier ensembles and genetic algorithm. Gaussian process classification, quadratic discriminant analysis, support vector machine, artificial neural networks, adaptive boosted decision trees, and k‐nearest neighbours were chosen to be individual AI techniques, and the weighted majority voting was used as the combination method. Validation method was chosen to be the 10‐fold cross‐validation, and performance measures were selected to be the accuracy, the receiver operating characteristic curve, and the area under the receiver operating characteristic curve (AUC). Grid search and genetic algorithm were used for the hyperparameter tuning and weight tuning respectively. The results show that the proposed hybrid ensemble method has great potential in improving the prediction of slope stability. Compared with individual classifiers, the optimum ensemble classifier achieved the highest AUC value (0.943) and the highest accuracy (0.902) on the testing set, denoting that the predictive performance has been improved. The optimum ensemble classifier with the Youden's cut‐off was recommended for slope stability prediction with respect to the AUC value, the accuracy, the true positive rate, and the true negative rate. This research indicates that the use of the classifier ensembles, rather than the search for the ideal individual classifiers, might help for the slope stability prediction.     

The effect of density-driven flow on the transport of high-concentration solutes in the hyporheic zone

In this study, both laboratory experiments and numerical simulations were conducted to investigate the effect of density-driven flow on the transport of high-concentration pollutants in the hyporheic zone. The results show that the density gradient can change the flow of pore water and the strong density-driven flow can lead to an unstable flow, which increases the effect of preferential flow and thus causes the appearance of solute fingers in the hyporheic zone. Notably, these solute fingers become more obvious with the increase of depth. The appearance of solute fingers depends on the relative strength of the pumping exchange and density gradient, which are represented by the dimensionless number M* and N* respectively. Finger flows appear near the interface when M^* is less than 0.5 N^*. This study may contribute to better understanding the transport and destination of solutes and thus may provide some insights into the assessment on pollution incidents.     

简单随机模式进一步分析(Ⅰ)——非线性外通函数项处理

本文利用等效线性化法和Fokker-planck方程,对一个简单的非线性随机模式非线性项在不同气候时期的参数化进行了讨论,得到了冰期、间冰期和现代气候的概率分布密度及输出响应特征。     

景泰地震前后兰州台的中期形变异常

给出了兰州台浮子水管倾斜仪和石英伸缩仪１９８７～１９９３年间Ｍ２波潮汐因子的年度调和分析结果，然后对各分量月均值进行了残差分析，并绘出去除长期项后的倾斜矢量图，据此探讨了景泰地震的中期前兆异常和震后效应特征。