Land transfer,collective action and the adoption of soil and water conservation measures in the Loess Plateau of China

Natural Hazards - Based on the data of 849 rural households in the Loess Plateau of China, this paper uses exploratory factor analysis to study farmers’ participation in collective action...     

Geochemistry of dissolved and particulate elements in the major rivers of China (The Huanghe,Changjiang, and Zhunjiang rivers)

The relationship between the geochemistry of dissolved and particulate materials and geographic conditions was investigated. Samples of water and suspended particulate matter were collected from five locations in three of the major rivers of China (the Huanghe, Changjiang, and Zhunjiang rivers). Because these rivers generally flow parallel to latitudes and flow through diverse geologic and climate zones, they provide excellent opportunities for comparisons of solute transport. The geochemistry of these rivers is influenced strongly by climate. The low discharge of the Huanghe River influences the character of the major ionic materials (Cl^?+SO₄ ^2? and Na⁺+K⁺) as well as the high degree of mineralization within the system. Dissolved concentrations of both major ions and trace elements are lower in the southern reaches of the rivers. The highly mobile ions, such as, Na⁺ and Ca²⁺, are depleted from the suspended particulate material in the southern regions, while the relatively immobile ions of Al, Fe, Ti, Mn, and trace metals are concentrated within the suspended mateiral. The relative mobility of some elements as measured by the Dissolved Transport Index (DTI) changes with climate. The geology of the area drained by the rivers has a major influence on the geochemistry in areas of similar climate. Lowest leaching rates in the southern climates occur in areas dominated by granite, which is resistant to weathering. The composition of both cations and anions among the three tributaries of the Zhujiang River are dependent on the rocks that dominate each eregion. Some particulate forms of the rare earth elements are present in the highest concentrations in regions dominated by granite. The DTI calculated for the major rivers in China are much smaller than those computed for other major rivers of the world. The low concentration of heavy metals in the particulate material suggests that pollution in the rivers of China is less serious than in rivers of other industrialized countries.     

One‐dimensional consolidation with a threshold gradient: a Stefan problem with rate‐dependent latent heat

During the process of one‐dimensional consolidation with a threshold gradient, the seepage front moves downward gradually, and the problem is indicated as a Stefan problem. The novel feature in this Stefan problem is a latent heat that varies inversely with the rate of the moving boundary. An exact solution for the external load that increases in proportion to the square root of time is constructed using the similarity transformation technique. Computational examples concerning the effect of different parameters on the motion of the seepage front are presented. The exact solution provides a worthwhile benchmark for verifying the accuracy of numerical and approximate methods. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis and characterisation of a multifunctional oil-based drilling fluid additive

An oil-based drilling fluid additive H-DEA (or humic acid-cocamide diethanolamine) was synthesised using humic acid and cocamide diethanolamine as raw materials. The rheological behaviors of H-DEA showed that the synthesised product has the good properties in both decreasing the filtrate loss and improving rheology property of oil-based drilling fluids compared with other commercially available additives. Under the optimal additive amount of 3%, both API filtrate loss and yield point changed remarkably from 5.40 to 0.41 mL and 9.0 to 25.6 Pa, respectively. Furthermore, differential scanning calorimetry (DSC) showed that H-DEA has good thermal stability in a wide temperature range up to 170 °C. Infrared spectroscopy (IR) and rheological analysis revealed that the possible mechanism of the multifunctional effects may be attributed to the existing of high density of strong polar groups, hydrogen bonds, electrostatic forces, and intermolecular association on H-DEA molecular structure. The results of the study showed that the synthesised H-DEA can be potentially used as a multifunctional oil-based drilling fluid additive in oil-drilling excavation.     

敦化市大石河钼矿床地球化学及矿物学特征

本文简单地介绍了大石河大型隐爆角砾岩筒型钼矿床的地质特征,详细地介绍了矿床的地球化学特征和矿物学特征及找矿标志和找矿方向,对在吉林延边地区北部蛟河—敦化一带分布的晚元古代变质岩地层区寻找大、中型多种成因类型的钼矿床具有重要的指导意义。     

长乐-南澳韧性剪切带走滑特征探讨

长乐-南澳韧性剪切带可能是在碰撞造山缝合带基础上发育的,其走滑特性严格受闽台微大陆与闽浙中生代火山弧碰撞过程中碰撞动力学的制约。岩石韧性组构和糜棱岩变形的微构造研究表明,碰撞前期走滑为左行。在早垩世晚期(100-120Ma)的主碰撞期和以伸展作用为主的碰撞后期,该带以右行为主,这种右行走滑一直持续至今。发育韧性剪切带的闽台微大陆(或称平潭-东山带)原始位置可能比现今更靠南,这是属于几百公里的漂移位移而不是剪切位移。     

鄂尔多斯西南缘前陆盆地沉降和沉积过程模拟

本文将东祁东逆冲带与鄂尔多斯西南缘晚三叠世前陆盆地相结合，研究了逆冲带内部变形特征，前陆盆地中层序地层格架特征及其反映的盆缘构造性质和幕式逆作作用。     

Geographical Conditions and National Strategies

This paper is a summary based on the relationship between national conditions and development strategies for decades of consulting research. Through cases, the paper outlined the basic meaning of national conditions and geographical conditions and their close relationship with national development strategies, and emphasized the importance of comprehensive thinking and scientific judgment in the process of carrying out the governments’ strategies and development policies, and making development policies. At last, suggestions were made that the points of China’s national conditions and the rules of connection with government decision-making should be written into geography textbooks as well as into textbooks for party schools of the Communist Party of China.