荧光催化动力分析法测定痕量钌

在碱性介质中,痕量Ru对邻羟基苯基荧光酮与H_2O_2的氧化还原反应有催化作用。据此,本文拟定了高灵敏测Ru的荧光催化动力学方法。实验操作简单,Ru的检出限为5×10~(-11)g/ml。     

萨拉乌苏河流域高分辨率的沙丘砂常量元素分布指示的全新世寒冷事件

The components of the primary elements in the dune sands for the MGS1 subsection of the Milanggouwan section in the Salawusu River valley, compared with those of modern dune sands, show that they were caused by East Asian winter monsoon in the Mu Us desert during Holocene. The examined ages for the 11 layers of dune sands, based on the average sedimentary rate, are： 0 to 960, 1350-2240, 2470 to 3530, 4000 to 4180, 4290 to 4350, 4380 to 4760, 5040 to 5920, 6570 to 8270, 9020 to 9700, 9880 to 10160 and 10580 to 11080 a BP, respectively. The climatic events indicated by these dune sands are consistent with those records in the Huguangyan volcanic lake, Zoige peat bog, Hulu cave and Dunde ice core, particularly with the climatic fluctuations of the North Atlantic since 11 000 a BP. Among them, patterns from B0 to B8 correspond to the peak values of 0MD, 2D, 4D, 6D＋8D＋10D, 12D, 14D, 16D, 18D and 20D respectively. It might be caused by the North Atlantic ice age induced by the heat circulation, which strengthened the polar high pressure and Siberian-Mongolian high pressure and further led to the dominance of the winter monsoon over China＇s desert area.     

Discovery of bauxite-type helium source rock in Jinzhong basin,central North China and its resource potential evaluation

<正>1. Objective Among globally known industrial helium-enriched natural gas reservoirs, associated helium is dominantly crust-derived helium(4He), which is generated by the radioactive decay of uranium(U) and thorium(Th) in crustal rocks. These rocks with old ages are also defined as helium source rocks.Published accumulation models for helium have revealed that granite is the main and effective helium source rock in the crust(Li YH et al., 2018).     

Chemical compositions of snow from Mt. Yulong,southeastern Tibetan Plateau

The snow and ice in Mt. Yulong offer a unique opportunity to investigate changes in climate and large scale atmospheric circulations over Asia. During February and April 2012, surface snow samples were collected from the Baishui Glacier No. 1 at different altitudes along the eastern slope of Mt. Yulong. Two snowpits were also excavated from Mt. Yulong at altitudes of 4780 and 4730 m a.s.l. in February 2012. The concentrations of inorganic ions were higher at an elevation of 4506 m a.s.l. in the glacier with significant contribution of anthropogenic (mainly NH\(_{4}^{\mathrm {+}}\), SO\(_{4}^{\mathrm {2-}}\), NO\(_{3}^{\mathrm {-}})\) and crustal (mainly Ca ²⁺) constituents. Concentration of HCOO ^? in surface snow exhibited large variability, ranging from 0.04 to 6.8 μeq L ^?1, attributed to dominant contribution from biomass burning emissions. Ion balance (ΔC) and Na ⁺/Cl ^? calculations indicated an excess of cations (particularly higher Ca ²⁺ concentrations) and Cl ^? in snow, considering the sea-salt ratio, respectively. Monsoon season (June–September) ion concentrations in snowpit samples were generally two-fold lower than in other seasons. Principal component analysis was used to identify different sources of ions. Three main factors, accounting for more than 80% of the total variance, were related to different sources, including agricultural activities, biomass burning, and crustal aerosols.     

Dynamic Response of Shallow-Buried Small Spacing Tunnel with Asymmetrical Pressure: Shaking Table Testing and Numerical Simulation

A series of shaking table tests were designed and carried out to study the seismic behaviors of a shallow-buried small spacing tunnel with asymmetrical pressure. The key details to shaking table model test, including test equipment, model similarity relation, similarity constant, model box, physical model, layout of transducers, seismic waves, and loading system were presented. The numerical simulation of the shaking table test was also carried out by using a finite element simulation software. The results show that: (1) the Fourier spectrums in the vertical direction and horizontal direction are different at the same measuring point. The structure of tunnel transforms the Fourier spectrum of horizontal direction. (2) The stability of middle rock pillar is poor under seismic wave action. The anchor plays an important role in strengthening the stability of middle rock pillar. The dynamic strain of anchor has accumulative effect. (3) The numerical simulation results are in significant agreement with the shaking table test results. (4) Compared with type of seismic wave, peak seismic wave has a significant effect on acceleration response of tunnel. The peak acceleration response of the tunnel is linear with the peak seismic wave, in the horizontal direction. The peak acceleration response is nonlinear in the vertical direction. (5) The axial force of cross section at arch foot is larger than other position. The shock absorption effect of 10 cm seismic isolation layer is better than 5 and 20 cm.     

A paired metamorphic belt in a subduction‐to‐collision orogen: An example from the South Qilian–North Qaidam orogenic belt,NW China

The early Palaeozoic South Qilian–North Qaidam orogenic belt in northwestern China records a nearly complete history of early‐stage long‐lived oceanic subduction–accretion followed by late‐stage continental collision. Most previous studies have focused on low dT/dP metamorphism (HP–UHP) in this belt whereas the paired high dT/dP belt in the hinterland has received little attention. In this contribution, phase equilibrium modelling is combined with zircon petrochronology to determine the P–T–t evolution of granulites in the North Wulan gneiss complex in the high dT/dP hinterland of the South Qilian–North Qaidam orogen. Granulites record a clockwise P–T path with near‐peak temperatures of ~800–900°C at 5.5–7 kbar. Peak metamorphism was followed by high‐T decompression. Zircon petrochronology reveals protracted zircon growth from c. 474 to 446 Ma during the high‐T portion of the P–T path. High dT/dP metamorphism in the North Wulan gneiss complex was likely the result of heat transfer from the underlying hot asthenosphere and minor coeval magmatism in an arc–back‐arc system during slab retreat and roll‐back of the South Qilian oceanic plate. Broadly contemporaneous but slightly younger HP–UHP metamorphism in the foreland of the South Qilian–North Qaidam orogenic belt indicates that the region records an early Palaeozoic paired metamorphic belt. This early Palaeozoic paired metamorphic belt provides a detailed example of dual thermal regimes in a modern‐style orogenic system that can be applied to understanding the time‐scales and P–T conditions of high dT/dP metamorphism that accompany subduction in Phanerozoic and Precambrian orogenic belts.     

Correlation acceleration in GNSS software receivers using a CUDA-enabled GPU

GPS Solutions - The correlation process in a GNSS receiver tracking module can be computationally prohibitive if it is executed on a central processing unit (CPU) using single-instruction...     

Effects of differential hillslope‐scale water retention characteristics on rainfall–runoff response at the Landscape Evolution Observatory

Hillslopes turn precipitation into runoff and thus exert important controls on various Earth system processes. It remains difficult to collect reliable data necessary for understanding and modeling these Earth system processes in real catchments. To overcome this problem, controlled experiments are being conducted at the Landscape Evolution Observatory at Biosphere 2, The University of Arizona. Previous experiments have revealed differences in hydrological response between 2 landscapes within Landscape Evolution Observatory, even though both landscapes were designed to be identical. In an attempt to discover where the observed differences stem from, we use a fully 3‐dimensional hydrological model (CATchment HYdrology) to show the effect of soil water retention characteristics and saturated hydraulic conductivity on the hydrological response of these 2 hillslopes. We also show that soil water retention characteristics can be derived at hillslope scale from experimental observations of soil moisture and matric potential. It is found that differences in soil packing between the 2 landscapes may be responsible for the observed differences in hydrological response. This modeling study also suggests that soil water retention characteristics and saturated hydraulic conductivity have a profound effect on rainfall–runoff processes at hillslope scale and that parametrization of a single hillslope may be a promising step in modeling rainfall–runoff response in real catchments.     

北京城市贫困人口特征,成因及其解困对策

在经济与社会转轨时期,北京城市贫困人口总量显增加,并出现贫困人口群体多样化特征。贫困人口的成因既受国家经济结构高速和体制改革等的制约,也受人口自身身体状况、化素质和思想观念等的影响,因此,需要采取多种措施摆脱贫困。     

航空遥感技术在新疆和硕-库尔勒段高速公路工程地质调查中的应用

在利用TM 图像进行区域工程地质条件分析的基础上,利用大比例尺航空像片,对新疆和硕-库尔勒段高速公路正线及比较线进行路线工程地质调查,并结合钻探、触探,探地雷达测试,对路线工程地质条件进行综合评价。