Hydrothermal pattern of frozen soil in Nam Co lake basin,the Tibetan Plateau

Hydrothermal processes and the regimes of frozen soil formed in alpine regions with glaciers and lake area are complex and important for ecological environment but have not been studied in Tibet. Based on soil temperature and moisture data from October 2005 to September 2006 collected in the Nam Co lake basin, Tibetan Plateau (TP), those questions were discussed. The mean annual air temperature was −3.4°C with 8 months below 0°C. Air and soil temperature varied between −25.3~13.1°C and −10.3~8.8°C, respectively. Soil moisture variations in the active layer were small with the minimum value of 1.4%, but were influenced greatly by snowmelt, rainfall and evaporation, varying up to 53.8%. The active layer froze later, thawed earlier and was thinner, however, the lower altitude limit of permafrost is higher than that in most areas of TP. The effects of soil moisture (unfrozen water content) on soil temperature, which were estimated through proposed models, were more significant near ground surface than the other layers. The surface soil temperature decreased with snowcover, the effect of cold snow meltwater infiltration on soil thermal conditions was negligible, however, the effect of rainfall infiltration was evident causing thermal disruptions.     

氧化铬柱支撑蒙脱石的制备研究

以浙江和新疆的膨润土为原料合成了氧化铝柱支撑蒙脱石,成柱溶液以Na2CO3为碱水解铝盐溶液制得。因为制备含有大聚羟基铬阳离子的成柱溶液是获得具有大的基面间距的柱支撑粘土的关键,我们详细研究了CO32-／Cr3＋值、水解温度和水解时间对所得柱支撑蒙脱石性质的影响。聚羟基铬阳离子通过阳离子交换引入蒙脱石,所得产物用X射线衍射分析和BET氮比表面等方法研究。所得氧化铝柱支撑蒙脱石（简称Cr－mont）的基面间距为2．55nm,BET氮比表面积为190～230m2／g。     

Phosphorus biological cycle in the different Suaeda salsa marshes of the Yellow River estuary, China

Much uncertainty exists in the phosphorus (P) cycle in the marshes of the intertidal zone. This study explored the P cycling in the two Suaeda salsa marshes [middle S. salsa marsh (MSM) and low S. salsa marsh (LSM)] of the Yellow River estuary during April 2008 to November 2009. Results showed seasonal fluctuations and vertical distributions of P in different S. salsa marsh soils, and variations in P content in different parts of plants due to water and salinity status. The N/P ratios of the different S. salsa were 9.87 ± 1.23 and 15.73 ± 1.77, respectively, indicating that plant growth in MSM was limited by N, while that in LSM was limited by both N and P. The S. salsa litter in MSM released P to the environment throughout the year, while that in LSM immobilized P from the environment at all times. The P absorption coefficients of S. salsa in MSM and LSM were very low (0.0010 and 0.0001, respectively), while the biological cycle coefficients were high (0.739 and 0.812, respectively). The P turnovers among compartments of MSM and LSM showed that the uptake amounts of roots were 0.4275 and 0.0469 g m^?2 year^?1 and the values of aboveground parts were 1.1702 and 0.1833 g m^?2 year^?1, the re-translocation quantities from aboveground parts to roots were 0.8544 and 0.1452 g m^?2 year^?1, the translocation amounts from roots to soil were 0.0137 and 0.0012 g m^?2 year^?1, the translocation quantities from aboveground living bodies to litter were 0.3157 and 0.0381 g m^?2 year^?1, and the annual return quantities from litter to soil were less than 0.0626 and ?0.0728 g m^?2 year^?1 (minus represented immobilization), respectively. P was an important limiting factor in S. salsa marshes, especially in LSM. S. salsa was seemingly well adapted to the low-nutrient condition and the vulnerable habitat, and the nutrient enrichment due to the import of N and P from the Yellow River estuary would be a potential threat to the S. salsa marshes.     

盆地深部穹隆构造发育特征、成因机制及石油地质意义——以塔里木盆地顺北地区为例

塔里木盆地顺北地区奥陶系碳酸盐岩中广泛发育穹隆构造.为研究盆地深部穹隆构造的发育特征、成因机制及石油地质意义,基于顺北地区高精度三维地震资料,对穹隆构造开展几何学定量解析,确定其空间分布规律及内部结构样式;结合区域构造背景及盆内构造发育特征,明确其成因机制;在此基础上,结合生产动态数据探讨穹隆构造的控储—控藏作用.研究...     

The Fragmentation in a Protoplanetary Disk and the Properties of the Resultant Self-Gravitating Clumps

We study the fragmentation properties in the protoplanetary disk and properties of the resultant self-gravitating clumps using our newly constructed disk model. Our disk model includes the mass inflall term from a molecular cloud core and the photoevaporation winds effect. We adopt the conventional fragmentation criterion to judge whether a protoplanetary disk can fragment. In this work, we follow our previous work to investigate the properties of the resultant self-gravitating clumps. In our calculation, the initial masses of the resultant self-gravitating clumps lie in the range of tens of M_J to more than one hundred of M_J, where M_J is the Jupiter mass. These initial masses can seemingly account for the masses of extrasolar planets in magnitude. We also calculate the subsequent gas accretion of clumps in 1.27 × 10⁴ yr after the formation of self-gravitating clumps. We find that the subsequent gas accretion of self-gravitating clumps is very efficient, and the clump masses grow to hundreds of M_J and the physical radii R_c of clumps increase to about 10 AU. Additionally, we also calculate the orbital migration of clumps. We find that most clumps have short migration timescale to be accreted onto the protostar, and only a small fraction of clumps have long migration timescale (>10⁶ yr) to successfully become gas giant planets. These results are consistent with previous studies.     

A nonlinear multiparameter prestack seismic inversion method based on hybrid optimization approach

Multiparameter prestack seismic inversion is one of the most powerful techniques in quantitatively estimating subsurface petrophysical properties. However, it remains a challenging problem due to the nonlinearity and ill-posedness of the inversion process. Traditional regularization approach can stabilize the solution but at the cost of smoothing valuable geological boundaries. In addition, compared with linearized optimization methods, global optimization techniques can obtain better results regardless of initial models, especially for multiparameter prestack inversion. However, when solving multiparameter prestack inversion problems, the application of standard global optimization algorithms maybe limited due to the issue of high computational cost (e.g., simulating annealing) or premature convergence (e.g., particle swarm optimization). In this paper, we propose a hybrid optimization-based multiparameter prestack inversion method. In this method, we introduce a prior constraint term featured by multiple regularization functions, intended to preserve layered boundaries of geological formations; in particular, to address the problem of premature convergence existing in standard particle swarm optimization algorithm, we propose a hybrid optimization strategy by hybridizing particle swarm optimization and very fast simulating annealing to solve the nonlinear optimization problem. We demonstrate the effectiveness of the proposed inversion method by conducting synthetic test and field data application, both of which show encouraging results.     

临海浅埋富水明挖隧道底板合理支护参数研究

沿海地区深基坑设计施工都十分重视其抗浮问题,在深基坑开挖前掌握抗拔桩对于基坑隆起和围护结构变形及受力规律十分重要,其研究成果对于节约工程成本和保证基坑施工安全具有重要的指导意义。以港珠澳大桥侧接线拱北海关隧道明挖段为依托,首先建立抗拔桩与土体的硬接触模型,并验证该模型对于抗拔桩模拟的合理性,采用极差分析法研究底板不同桩长和桩径加固对基坑围护结构稳定性的影响规律。分析结果表明,增大桩长可更有效地减小地表沉降,增大桩径可更好地控制连续墙的变形,增大桩长和桩径都可以很好地控制坑底隆起。     

冀北坝上地区深部地质构造特征及其对火山活动和铀成矿的控制作用

冀北坝上地区位于华北地台北缘。其深部地质构造有两个显著特征：一是全区性的莫霍面下拗，地壳增厚；二是软流圈部分伸入到下岩石图上部，造成局部地区地幔上隆，地壳减薄。火山喷发形成的沽源火山盆地和大滩火山盆地与两个地幔上隆，地壳减薄区，上下相互对应。铀矿床（点）沿地幔隆起周边构造活动带规律性分布。上述两事实有力地证明了深部地质构造对中新生代火山活动和铀成矿的控制作用。沿地幔隆起周边构造活动带是今后寻找铀及多金属矿产的有利地段。     

Mechanical characteristics of dip basement effects on dump stability in the Shengli open pit mine in Inner Mongolia,China

For waste dump slopes that form basements, landslides can be prevented by determining a stability evolving law of dynamic development. Keeping this issue in mind, the relationship between the mechanical structure and stability of waste dumps with basements is studied. Three key factors that influence waste dump stability are presented, and judgment criteria for self-locking and unlocking states of dump basements are provided. From the friction coefficient of waste dump basement stability analyses of the Shengli open pit mine, the results indicate that waste dump basements on the right side of fault F8 and on the left side of fault F61 are subjected to self-locking. However, between faults F61 and F8, the basement is subjected to unlocking. Regarding the residual thrusting of unlocking areas, structure and stability optimization schemes for waste dumps in the Shengli open pit mine are provided through a mechanics analysis. Reducing the slopes and basement angles of waste dumps can enhance their stability by increasing basement roughness levels.