河北围场天然沸石的矿物学特征及吸附性研究

河北承德围场地区含有储量丰富的天然沸石资源,然而目前关于该地区天然沸石的研究较少。本文利用X射线衍射仪、X射线荧光光谱仪、红外光谱仪、比表面积及孔隙度分析仪和扫描电镜及能谱分析仪等对围场天然沸石的矿物学特征进行了研究,并分析了围场天然沸石对苯、甲苯和水蒸气等的吸附性。结果发现,该地区天然沸石主要含斜发沸石和石英,硅铝比为5. 3,样品中含有少量微孔和大量介孔,具有相对较高的比表面积;样品对苯、甲苯和水蒸气均具有良好的吸附效果。     

云南勐腊新山铁多金属矿矿化富集规律

新山铁多金属矿矿床规模大、品位高、共（伴）生有铜铅锌银等多种有用组份。经历了火山（海相）喷发、生物化学沉积、成岩作用、地下热水循环改造等多期成矿阶段,属火山喷发沉积—改造（层控碳酸盐）型矿床。     

Discussion on the Use of 7Be to Estimate Soil Erosion Rates

⁷Be is a naturally occurring cosmogenic radionuclide produced in the stratosphere and troposphere as a result of cosmic ray spallation of nitrogen and oxygen. The constant fallout via precipitation and short half-life (53.3 days), coupled with shallow depth distribution in soil profile (~2 cm) provide the unique advantages for its application as a soil and sediment tracer over short timescales, such as a single storm or short period of extreme rainfall. With the climate change and increasing rainfall events, the ⁷Be tracing method will exhibit wide application prospect in future. To date, however, this technique is still in its infancy and some important assumptions have not yet been effectively validated. Consequently, the use of ⁷Be to document soil erosion rates has been limited. This contribution briefly reviews the history and current status relating to this tracing method. In addition, the basic principles and recent research progresses in conversion models for use of ⁷Be measurements to estimate soil redistribution rates are introduced. The key assumptions and uncertainties of the technique, as well as the effects of the vegetation interception and particle size selectivity are discussed. Additionally, some new investigation directions are provided, including the assumption validation and uncertainty analysis, the impact of vegetation interception, the extending of spatial and temporal scales, and the development of new conversion models.     

Morphological reactions of schematic alluvial rivers:Long simulations with a 0-D model

The paper presents a 0-D model of an alluvial watercourse schematized in two connected reaches, evolving at the long time-scale and under the hypothesis of Local Uniform Flow. Each reach is defined by its geometry (constant length and width, time-changing slope) and grain-size composition of the bed, while the sediment transport is computed using a sediment rating curve. The slope evolution is provided by a 0-D mass balance and the evolution of the bed composition is computed by a 0-D Hirano equation. A system of differential equations, solved with a predictor-corrector scheme, is derived and applied to the schematic watercourse to simulate the morphological response to changing initial conditions, and the evolution towards long-term equilibrium conditions. Differently from a single-reach 0-D schematization with uniform grain-size, besides the simplifications adopted, the model proposed here simulates the behaviour of alluvial rivers in a physically-based way, showing a grain-size fining in the downstream direction accompanied by milder slopes, and a tendency to develop concave longitudinal profiles.     

不同开采方法下深海能源土离散元模拟

天然气水合物以胶结及孔隙填充等形式存在于深海能源土中,开采时因其分解会劣化地层力学特性进而引发海底事故,使得人们对能源土开采过程进行中力学特性的变化愈发重视。在前期室内试验的基础上,将一个温度-水压-力学二维微观胶结模型引入离散元商业软件PFC2D中,通过对排气、排水性较好的土体进行升温及降压法开采进行数值模拟,并将模拟结果与相同条件下的室内试验结果对比,验证了该胶结模型的适用性。进一步分析了颗粒接触分布与颗粒平均纯转动率（averaged pure rotation rate, APR）在水合物分解时的变化情况。升温分解过程中随温度升高,颗粒总接触分布各向异性程度增大;胶结接触逐渐减少并始终保持主方向为水平方向,无胶结接触增多并始终保持主方向为竖直方向;APR值逐渐增大且正负值分布逐渐趋于集中。降压分解过程中随反（水）压降低,颗粒总接触由各向同性分布逐渐发展为主方向为竖直方向的各向异性,APR值较小且分布均匀;恢复反压后,试样进一步破坏,颗粒总接触各向异性更加明显,APR值增大且正负值呈集中分布。     

原子吸收光谱仪用于沉积物中锡分析的方法研究

１９９４－１９９６年间,利用原子吸收光谱仪,对沉积物中有机锡和总锡的石墨炉原子吸收分析方法进行了优化,探讨了分析过程中的仪器条件和改进剂类型。优化后方法的检出限为 ２．４５μｇ／Ｌ（ＴＰＴ－锡）,特征浓度（相当于产生 １％净吸收或 ０．００４ ４吸光度的待测元素浓度）为４８２μｇ／Ｌ（ＴＰＴ－锡）。在这一条件下,采用盐酸酸化－正己烷萃取－氢氧化钠回洗－硝酸氧化的预处理方法,可以使沉积物样品中三苯基氯化锡（Ｔｒｉｐｈｅｎｙｌｔｉｎ, ＴＰＴ）的检出限达到４１ｎｇ／ｇ（ＴＰＴ－锡）,回收率为 １０６％。应用这一方法对野外模拟实验和黄岛电厂出水口的沉积物样品进行了分析,结果表明,这一方法能够满足对沉积物样品中锡进行分析的要求。     

Origins and maturity of organic matter in mid-Cretaceous black shales from ODP Site 1138 on the Kerguelen Plateau

We have conducted elemental, isotopic, and Rock-Eval analyses of Cenomanian–Santonian sediment samples from ODP Site 1138 in the southern Indian Ocean to assess the origin and thermal maturity of organic matter in mid-Cretaceous black shales found at this high-latitude location. Total organic carbon (TOC) concentrations range between 1 and 20 wt% in black to medium-gray sediments deposited around the Cenomanian–Turonian boundary. Results of Rock-Eval pyrolysis indicate that the organic matter is algal Type II material that has experienced modest alteration. Important contributions of nitrogen-fixing bacteria to the amplified production of organic matter implied by the high TOC concentrations is recorded in δ¹⁵N values between −5 and 1‰, and the existence of a near-surface intensified oxygen minimum zone that favored organic carbon preservation is implied by TOC/TN ratios between 20 and 40. In contrast to the marine nature of the organic matter in the Cenomanian–Turonian boundary section, deeper sediments at Site 1138 contain evidence of contributions land-derived organic matter that implies the former presence of forests on the Kerguelen Plateau until the earliest Cenomanian.     

Erodibility study of sediment in a fast-flowing river

Determination of sediment stability in the field is challenging because bed shear stress (BSS), a determining factor of sediment erosion, can’t easily be directly measured. To tackle this challenge and reliably assess sediment erodibility in a fast flowing river, a standalone underwater camera system and a new insitu flume (ISF) were developed and applied in this study. The camera system was used to record sediment movement and the new ISF was used for measuring critical bottom shear stress (CBSS). The camera can be deployed alone in water to record videos or take pictures with light emitting diode (LED) lighting and flexible schedule settings. The ISF is based on the concept that the amount of force needed to erode the same particle under different flow conditions should be similar. Two high resolution Acoustic Doppler Current Profilers (ADCP) also were deployed in the field to collect velocity-depth profiles which are used by conventional methods to calculate BSS with the law of the wall. The sediment erodibility was then assessed based on the comparison between the obtained CBSS and BSS and then further verified with the recorded observations from the deployed camera. The results reveal that the widely used conventional method can produce large uncertainties and is not adequate to provide meaningful conclusion under these conditions.     

High flow events and sediment transport in small streams in the ‘tertiary basin’ area in piedmont (Northwest Italy)

Rainfall, peak discharges, and suspended sediment transport were surveyed for 280 events in three small (0.8 to 10 km²) catchments in a hilly area derived from Neogene marls, silts, and sands. Under similar hydrological input conditions, stream flow behaviour and sediment delivery differed considerably from one catchment to another, depending on topography, lithology, land use, and especially sediment availability. Analytical treatment of data showed a good fit between sediment yield and peak flow discharge. Less good, although still significant, was the correlation between sediment concentration and discharge values for different flow stages. Rainfall peak/basin lag time and rainfall/discharge showed poor or no correlation, mainly due to strong variations in rainfall distribution. Sediment concentration in the catchments varied enormously according to season, from zero up to 334 g 1^?1; sediment yield was 160-900 tonnes km^?2 yr^?1 in the two major catchments, and over 5200 tonnes km^?2 yr^?1 in the headwater catchment, stressing the importance of small tributaries not only in inducing floods in downstream channels, but also in sediment supply.     

合水地区长6油层微观渗流特征及驱油效率影响因素研究

对鄂尔多斯盆地合水地区长6油层组超低渗透储层的微观渗流特征及驱油效率影响因素进行深入研究,为提高采收率提供了科学依据。研究以真实砂岩微观模型渗流实验为主要手段,结合铸体薄片、扫描电镜、压汞等方法对孔隙结构、岩石类型等进行测试。研究表明,研究区长6油层的渗流特征以网状驱替和均匀驱替为主,指状驱替甚少;不同的驱替类型对应不同的最终驱油效率,均匀驱替模型最终驱油效率最高,指状驱替模型最低。储层物性中渗透率是影响驱油效率的主要因素,孔隙度次之;适当地提高驱替压力能够有效地提高驱油效率;提高注水体积倍数也能适当地提高驱油效率;非均质性对驱油效率也有一定的影响。