矿物结构与层间阳离子的固定与释放

分析２：１型矿物的结构差异、层间电荷性质以及在风化过程中某些性质的变化对是阳离子吸引力的影响，对已有报道中一些矛盾的结果或不具普遍意义的结论进行了讨论得出几我为明确的结论：（１）层间总电荷与四面体电荷所占比例大小共同决定矿物对层问阳离子的固定能力；（２）原生矿和扣八面体结构与层间阳离子固定间的关系对交矿物而言也许并不一致；（３）八 本中可变价阳离子的氧化还原，可导致矿物固定阳离子能力发生较大变化。     

在Xe^q＋（q=25，29）离子与Mo金属表面相互作用过程中离子动能及电荷态的作用

测量了Xe^25＋和Xe^29＋入射Mo金属表面发出的L壳层的x射线谱,观测入射离子动能范围在350～600keV之间的x射线强度．研究了x射线强度与入射离子动能及电荷态的关系,并给出了初步解释．     

在Xe~(q )(q=25,29)离子与Mo金属表面相互作用过程中离子动能及电荷态的作用

测量了Xe25 和Xe29 入射Mo金属表面发出的L壳层的X射线谱,观测入射离子动能范围在350～600keV之间的X射线强度.研究了X射线强度与入射离子动能及电荷态的关系,并给出了初步解释.     

Evidence for fixed charge in the nexus

The nexus or gap junction has been characterized as a low-resistance junction as well as a highly permeable junctional membrane to many molecules. The transfer of electrical current from one cell interior to another, the aqueous solubility of dyes used to trace cell to cell communication and the fact that these molecules move across the nexus more rapidly than the plasma membrane have led to the hypothesis of an aqueous channel in the junction. Both Ca2+ (ref.11) and H+ (ref. 12) are thought to alter nexal membrane conductance, and a voltage-sensitive gate has been demonstrated within the junction. Recently, Flagg-Newton et al. have concluded that mammalian junctions may contain fixed charge or be of smaller diameter than arthropod junctions. Here we have investigated these alternatives by examining the permeability of nexuses of septa of the median giant axon of Lumbricus terrestris with various derivatives of fluorescein. Both carboxyfluorescein and aminofluorescein were found to have depressed permeabilities relative to their predicted permeabilities based on molecular size and weight (MW). Flourescein diffusion was significantly suppressed in axons pre-injected with aminofluorescein but carboxyfluorescein had no such effect (Table 1). These data suggest the existence of fixed anionic charge within the nexal channel which may have affinity for amino groups.     

负载硝酸铵水凝胶的合成、表征及释放研究

以硝酸铵水溶液为介质,以丙烯酰胺、丙烯酸、丙烯酸羟丙酯和甲基丙烯酸缩水甘油酯为原料,通过自由基聚合制得高负载硝酸铵水凝胶.研究了负载硝酸铵水凝胶的缓释效果,结果表明,甲基丙烯酸缩水甘油酯用量和负载率对硝酸铵释放速率具有较大的影响.用红外光谱(IR)和电子扫描电镜(SEM)对负载硝酸铵水凝胶的结构进行了表征.     

Subsurface water and clay mineral formation during the early history of Mars

Clay minerals, recently discovered to be widespread in Mars's Noachian terrains, indicate long-duration interaction between water and rock over 3.7 billion years ago. Analysis of how they formed should indicate what environmental conditions prevailed on early Mars. If clays formed near the surface by weathering, as is common on Earth, their presence would indicate past surface conditions warmer and wetter than at present. However, available data instead indicate substantial Martian clay formation by hydrothermal groundwater circulation and a Noachian rock record dominated by evidence of subsurface waters. Cold, arid conditions with only transient surface water may have characterized Mars's surface for over 4 billion years, since the early-Noachian period, and the longest-duration aqueous, potentially habitable environments may have been in the subsurface.     

卫城油田沙四段粘土矿物的研究

卫城油田沙四段碎屑岩储层属于三角洲沉积,通过扫描电镜、X衍射分析表明,储层的粘土矿物主要有绿泥石、伊/蒙混层和伊利石及高岭石。并且粘土矿物随深度的增加呈规律的变化。绿泥石单体主要呈针叶片状,集合体为片状杂乱堆积、花朵状或绒球状,绿泥石以及孔隙充填式存在于颗粒间,减少了孔隙的空间。但同时又抑制了石英的次生加大,对原生孔隙的保存起了积极作用。伊利石粘土矿物单体呈片状、蜂窝状和丝缕状,集合体形态多为碎片状、鳞片状,以孔隙衬垫或孔隙充填物形式存在于颗粒间,导致砂岩中孔隙结构的明显破坏。高岭石单体呈全自形的六角板状晶体,集合体多呈蠕虫状、书本状。     

First-principles study of illite-smectite and implications for clay mineral systems

Illite-smectite interstratified clay minerals are ubiquitous in sedimentary basins and they have been linked to the maturation, migration and trapping of hydrocarbons, rock cementation, evolution of porewater chemistry during diagenesis and the development of pore pressure. But, despite the importance of these clays, their structures are controversial. Two competing models exist, each with profoundly different consequences for the understanding of diagenetic processes: model A views such interstratified clays as a stacking of layers identical to endmember illite and smectite layers, implying discrete and independently formed units (fundamental particles), whereas model B views the clays as composed of crystallites with a unique structure that maintains coherency over much greater distances, in line with local charge balance about interlayers. Here we use first-principles density-functional theory to explore the energetics and structures of these two models for an illite-smectite interstratified clay mineral with a ratio of 1:1 and a Reichweite parameter of 1. We find that the total energy of model B is 2.3 kJ atom(-1) mol(-1) lower than that of model A, and that this energy difference can be traced to structural distortions in model A due to local charge imbalance. The greater stability of model B requires re-evaluation of the evolution of the smectite-to-illite sequence of clay minerals, including the nature of coexisting species, stability relations, growth mechanisms and the model of fundamental particles.     

双价短链季铵盐改性黏土研究进展

烷基铵盐改性黏土的研究近年来引起了国内外学者的广泛关注,双价季铵盐的开发和利用为改性黏土的制备与性能研究开辟了新途径.综述了双价短链季铵盐及其复配体系改性黏土的吸附、膨胀性、稳定性、润湿性和催化性能,指出其基础研究的发展方向为有机改性黏土微观结构变化、水化膨胀过程中结合水类型的确定和界限的划分、结合水与有机改性黏土的水合机制等.     

黏土矿物微观孔隙结构的分形特征

以深部软岩中黏土矿物为研究对象,运用Image-proplus专业图像分析软件,对黏土矿物微观结构SEM图像进行处理,提取孔隙信息,结合分形理论,对微观孔隙结构进行分形数值分析。研究表明：软岩中黏土矿物微观孔隙结构分布具有分形特征,试样的分形维数在1~2。具有不同微观结构形态的相同类型黏土矿物和具有同种微观结构形态的不同类型黏土矿物,其分形维数均有差异。孔隙分布均匀程度与分形维数成反比。     

南票煤田热变煤中粘土矿物变化特征的研究

本文采用X射线分析方法，研究了南票煤田热变煤中粘土矿物的变化特征，由此得出该处岩石浆侵入时对煤层的影响范围和天然焦的形成温度。     

湿法浸出粘土矿中钒的动力学

为了提高湿法浸出粘土矿中钒的综合浸出效率,并对湿法浸出粘土矿中钒提供理论依据,从动力学角度分析整个浸出过程。考察温度、液固比、硫酸质量分数和搅拌速率对浸出过程的影响。研究结果表明：在80℃、液固比为4：1以及硫酸质量分数为20％时,浸取8h,粘土矿中钒的浸出率可达到92．3％。经正交实验和动力学推导,得到描述浸出过程的经验方程,粘土矿湿法浸出钒的动力学模型为收缩核动力学模型,浸出表观活化能为11．611kJ／mol,该模型表明浸出过程中的控制步骤是决定于固膜扩散速率。提高温度、液固比和硫酸质量分数,均可加速钒的浸出速度,提高钒的浸出率。