生物炭对土壤理化性质影响的研究进展简

Biochar is an organic material with high carbon content, most aromatic structure and great stability resulting from high temperature thermal conversion (usually < 700 ℃) of organic materials under the completely or in part anoxic condition. Due to its stable chemical properties, biochar has received widely attention as a strategy to reduce greenhouse gas emissions. In addition, biochar shows great potential in soil improvement and environmental pollution remediation, and provides a comprehensive solution for the global climate change, food crisis and ecological pollution remediation. Biochar is a carbon rich material, in association with porous characteristics and high surface area which are favorable to accumulating soil moisture, to increasing the porosity, to reducing density and bulk density, and to promoting the formation of soil aggregation. All the above soil physical improvement can provide a good environment for the growth of plants. Furthermore, biochar is an ideal acidic soil amendment which can improve the pH of acidic soil. It contains nutrient element which can be directly released into soil, and its surface charge and functional groups are conducive to soil nutrient retention, such as the reduced leaching of NH⁺₄ and NO^-₃, PO^3-₄, therefore improve the efficiency of nutrient elements. However, the effect of biochar amendments highly influenced by raw materials and pyrolysis conditions is of inconsistent and sometimes even contrast results can be concluded. In this paper, we summarize the current status and knowledge gaps about the effect of biochar amendments on soil physical and chemical properties and some suggestions are also strengthened. Finally, some possible negative impacts of biochar application and research suggestions are discussed in order to better use of biochar in agriculture.     

A comparative micromechanical analysis of the effective properties of a geomaterial: Effect of mineralogical compositions

In order to provide a physical interpretation of the variation of the mechanical properties of Callovo-Oxfordian argillite with mineral composition, we implement three linear homogenization schemes. The argillite is modeled as a three phase material composed of a clay matrix and inclusions of quartz and calcite. It is shown that, unlike the dilute scheme and the self-consistent scheme, the Mori-Tanaka model describes the in situ experimental data well. The determined properties are finally used in a finite element computation. The aim is to evaluate the effect of mineral composition on the elastic response of the excavation of a vertical shaft in the context of the underground laboratory of Meuse/Haute Marne.     

Prediction of rock burst classification using the technique of cloud models with attribution weight

Rock burst is one of the common failures in hard rock mining and civil construction. This study focuses on the prediction of rock burst classification with case instances using cloud models and attribution weight. First, cloud models are introduced briefly related to the rock burst classification problem. Then, the attribution weight method is presented to quantify the contribution of each rock burst indicator for classification. The approach is implemented to predict the classes of rock burst intensity for the 164 rock burst instances collected. The clustering figures are generated by cloud models for each rock burst class. The computed weight values of the indicators show that the stress ratio $ Ts = \sigma_{\theta } /\sigma_{c} $ Ts = σ θ / σ c is the most vulnerable parameter and the elastic strain energy storage index W _et and the brittleness factor $ B = \sigma_{c} /\sigma_{t} $ B = σ c / σ t take the second and third place, respectively, contributing to the rock burst classification. Besides, the predictive performance of the strategy introduced in this study is compared with that of some empirical methods, the regression analysis, the neural networks and support vector machines. The results turn out that cloud models perform better than the empirical methods and regression analysis and have superior generalization ability than the neural networks in modelling the rock burst cases. Hence, cloud models are feasible and applicable for prediction of rock burst classification. Finally, different models with varying indicators are investigated to validate the parameter sensitivity results obtained by cloud clustering analysis and regression analysis in context to rock burst classification.     

青藏高原东缘龙门山构造带晚第四纪构造隆升作用的河流地貌响应

基于ASTER GDEM数据,提取了青藏高原东缘龙门山地区12条基岩河道纵剖面,通过河流纵剖面形态的数学函数拟合、坡度-面积双对数函数关系以及基岩水力侵蚀模型的分析,探讨了龙门山北、中、南段不同河流水系地貌对其晚第四纪构造隆升运动的响应过程。研究表明：1）龙门山地区的河流纵剖面拟合形态中段多为对数型、指数型,南段多为指数型、直线型,北段均为对数型,表明了龙门山中段和南段的河流受构造运动的控制作用强烈,隆升较快,而北段隆升相对较慢。2）河流水力侵蚀模型中段多呈直线型和上凸型,南段均为上凸型,北段则呈直线型,表明了龙门山地区的河流水系地貌具有由SW向NE逐渐从前均衡状态向均衡状态转换的特征,指示了其构造隆升速率也由SW向NE逐渐递减。3）河流地貌的参数值表明了龙门山北段的河流地貌处于均衡状态,而龙门山中、南段的河流地貌则受构造隆升运动的影响较强;反映了青藏高原东缘向东扩展的时空格局。

     

点苍山新生代推覆构造的确立及其地质意义

点苍山地处三江构造带东缘，其东侧扬子陆块上的古生代地层，越过洱海断裂推覆到苍山西坡的中、新生代地之上：下泥盆统青山组推覆至下白垩统景星组之上；上二叠叠统乌龙坝组及红岩子组推覆在始新统宝相寺组之上。三江构造带中的上三维统歪古村组及三合洞组推覆在上侏罗统坝注路组之上。推覆时期为始新世－上新世，推覆构造机制是陆内汇聚挤压所至。     

近40 a来青海湖地区的气候变化分析

选用青海湖流域天峻、刚察、共和、茶卡4站41a(1958—1998年)的气象资料，用主成分分析、趋势分析和相关分析对各气象要素的年、季平均值序列进行了分析。结果表明：青海湖地区降水和日照时数的年际变化较大，但无明显的长期趋势；该地区的平均气温、平均最高、平均最低气温都明显升高，其中以平均最低气温上升最为明显；风速呈明显的下降趋势，20世纪70年代最大，80年代最小，90年代又略有增加；该区80年代相对湿度较大，而90年代向暖干发展。     

Characteristics of water circulation and balance of typical vegetations at plot scale on the Loess plateau of China

Large-scale artificial afforestation has aggravated the water scarcity and resulted in the severe soil desiccation in the Loess plateau of China. Understanding the water circulation processes and the water balance characteristics of typical vegetations is of great significance to the vegetation restoration in the Loess plateau of China. Based on field observation from May to October in 2004, the soil desiccation under five vegetations was investigated in the Liudaogou watershed on the Loess plateau of China. Moreover, the water circulation and balance of them at plot scale were also studied. The results showed that among these five vegetations, the degree of soil desiccation under alfalfa and caragana was more severe than that under defarming grassland, millet and soybean, and there existed the dried soil layers under caragana and alfalfa. The dynamic of the soil water storage under five vegetations was quite similar and the soil water storage in the five runoff plots followed the order: defarming grass > millet > soybean > caragana > alfalfa. The order of runoff amount in the five plots was soybean > millet > defarming grass > alfalfa > caragana. The water consumption (ET) of five vegetations followed the order: caragana > alfalfa > defarming grass > soybean > millet. The results indicated that the greater the evapotranspiration of one vegetation, the higher the possibility to develop the soil desiccation under it. The findings provided helpful reference for the vegetation restoration and environment improvement programs in the Loess plateau of China.     

Characteristics and dynamics origin of the Lower Cretaceous sill in northern Beilaishi section of Lingshan Island,Shandong Province

A lot of sand dikes are found in the Lower Cretaceous Laiyang Formation in northern Beilaishi section located in the Lingshan Island of Shandong Province. There are two types including bedding sand dikes and unbedding sand dikes based on their relationship with the bedding plane. The bedding sand dikes, which are often associated with soft sedimentary deformation, are mainly developed in the black mudstone of delta front, and their top and bottom interfaces are generally uneven. Based on the characteristics of sand dikes, the physical model and formula of bedding sand dikes under non-seismic condition are established. The relationship between the depth of liquefied sand layer, the emplacement depth and thickness of overlying sediment layer is deduced. It is considered that the depth of liquefied sand layer which forms large sand veins is very deep. This paper is of great significance in studying the origin of sand veins, lake related deposition and basin tectonic movement.     

培育密度、换水量和倒池培育对珠母贝浮游幼虫生长发育和存活的影响

以室内育苗池或玻璃缸养殖方式,研究了不同培育密度、换水量和倒池培育对珠母贝浮游幼虫生长发育和存活的影响。结果表明:当培育密度为0.8、1.2只/mL,直线铰合期时间分别为7.00、7.40d,日均生长为5.16、4.87μm,壳顶期时间分别为10.76d和10.77d,眼点期密度为0.58只·mL-1和0.60只·mL-1,差异不显著;日换水量分别为40%、60%、80%,直线铰合期时间、壳顶期时间、日均生长及眼点期密度差异不显著,日换水量40%能满足幼虫的生长和存活;壳顶初期进行倒池培育,能促进浮游幼虫的生长发育和提高其存活率。     

Petrogenesis and significance of the Mesozoic North Taihang complex: Major and trace element evidence

The intensive Mesozoic magmatism in the North China Craton (NCC) has drawn great attention for its particular geochemical signatures (e.g. high-K), petrogenesis and tectonic setting. The North Taihang complex represents the westernmost magmatic belt of th…