An extended multiple-support response spectrum method incorporating fluid-structure interaction for seismic analysis of deep-water bridges

The effects of ground motion spatial variability(GMSV) or fluid-structure interaction(FSI) on the seismic responses of deep-water bridges have been extensively examined. However, there are few studies on the seismic performance of bridges considering GMSV and FSI effects simultaneously. In this study, the original multiple-support response spectrum(MSRS) method is extended to consider FSI effect for seismic analysis of deep-water bridges. The solution of hydrodynamic pressure on a pier is obtain...     

Impact of the Yellow River capture on the paleoenvironmental changes of Hongze Lake,China

The Yellow River(YR) capture of the Huai River had a profound effect on the landscape evolution,ecology, and social development in China, disrupting the evolution of some vital shallow floodplain lakes.Because of the absence of lacustrine sediment provenance analysis, previous studies were inadequate in distinguishing the influence of YR capture on paleoenvironmental changes in these lakes, especially on landscape evolution, redox conditions, lake level changes, and organic productivity. The cur...     

Source characteristics of the mainshock and aftershocks of the 2019 Changning earthquake sequence: Implications for fluid effects

The 2019 M_S6.0 Changning earthquake occurred in the tectonically stable Sichuan Basin, where the epicenter and its adjacent areas are important shale gas and salt mine production fields, resulting in hot debates on whether the seismogenic mechanism of the 2019 Changning earthquake is related to human activities. As source characteristics and fluid pressure can provide important constraints on whether an earthquake is induced, weinvestigate the seismogenic mechanisms of the mainshock a...     

Magmatic-hydrothermal Evolution and Mineralization Mechanisms of the Wangjiazhuang Cu (-Mo) Deposit in the Zouping Volcanic Basin, Shandong Province, China: Constraints from Fluid Inclusions

The Wangjiazhuang Cu (-Mo) deposit, located within the Zouping volcanic basin in western Shandong Province, China, is unique in this area for having an economic value. In order to expound the metallogenetic characteristics of this porphyry-like hydrothermal deposit, a detailed fluid inclusion study has been conducted, employing the techniques of representative sampling, fluid inclusion petrography, microthermometry, Raman spectroscopy, LA-ICP-MS analysis of single fluid inclusions, as well as cathode fluorescence spectrometer analysis of host mineral quartz. The deposit contains mainly two types of orebodies, i.e. veinlet-dissemination-stockwork orebodies in the K-Si alteration zone and pegmatitic-quartz sulfide veins above them. In addition, minor breccia ore occurs locally. Four types of fluid inclusions in the deposit and altered quartz monzonite are identified: L-type one- or two-phase aqueous inclusions, V-type vapor-rich inclusions with V/L ratios greater than 50%–90%, D-type multiphase fluid inclusions containing daughter minerals or solids and S-type silicate-bearing fluid inclusions containing mainly muscovite and biotite. Ore petrography and fluid inclusion study has revealed a three-stage mineralization process, driven by magmatic-hydrothermal fluid activity, as follows. Initially, a hydrothermal fluid, separated from the parent magma, infiltrated into the quartz monzonite, resulting in its extensive K-Si alteration, as indicated by silicate-bearing fluid inclusions trapped in altered quartz monzonite. This is followed by the early mineralization, the formation of quartz veinlets and dissemination-stockwork ores. During the main mineralization stage, due to the participation and mixing of meteoric groundwater with magmatic-sourced hydrothermal fluid, the cooling and phase separation caused deposition of metals from the hydrothermal fluids. As a result, the pegmatitic-quartz sulfide-vein ores formed. In the late mineralization stage, decreasing fluid salinity led to the formation of L-type aqueous inclusions and chalcopyrite-sulfosalt ore. Coexistence of V-type and D-type inclusions and their similar homogenization temperatures with different homogenization modes suggest that phase separation or boiling of the ore-forming fluids took place during the early and the main mineralization stages. The formation P-T conditions of S-type inclusions and the early and the main mineralization stages were estimated as ca. 156–182 MPa and 450–650°C, 350–450°C, 18–35 MPa and 280–380°C, 8–15 MPa, respectively, based on the microthermometric data of the fluid inclusions formed at the individual stages.     

Discussion on the Measurement Method for the Coda Wave Quality Factor

The Quality factor is the parameter that can be used to describe the energy attenuation on seismic wave. In theory, we can obtain the relationship between the change of the coda wave quality factor with time and the strong earthquake preparation process on the basis of the quality factor of a coda wave in a same ray path. However, in reality the coda wave quality factor measured by different seismic coda waves corresponds to different seismic wave ray paths. The change of the quality factor with time is related to non-elastic characteristics of the medium and the volume of scattering ellipsoid constrained by scattered wave phase fronts, besides the change of regional stress field. This paper discusses the relationship between quality factor, epicenter distance and different lapse time, and then discusses the relationship between quality factor and frequency. Furthermore the determination method of the coda wave quality factor is put forward. The improved determination method of the quality factor, which removes the influence of different earthquakes or propagation depth of scattered waves, may increase measurement precision, thus information pertaining to abnormal changes in quality factor and the relationship between the quality factor and earthquake preparation process can be acquired.     

用非线性近似方法反演单多普勒雷达风场(英)

回顾了近年来由单多普勒雷达观测反演风场的各种方法。这些方法大部分基于线性假设,因此风场的非线性变化经常影响反演结果,使得反演的风场误差增大。我们提出一种以非线性近似理论为基础的反演方法,该方法主要考虑了风场分片光滑的特点并充分利用了雷达的径向风场数据。我们把该方法应用到1998年淮河能量与水循环实验的两个个例中。通过同双多普勒雷达观测的结果比较,发现该方法能反演较高分辨率和准确性的水平风场,反演的垂直风场也比较合理。     

New Evidence for Hydrothermal Sedimentary Genesis of the Ni‐Mo Deposits in Black Rock Series of the Basal Cambrian,Guizhou Province: Discovery of Coarse‐Grained Limestones and its Geochemical Characteristics

The molybdenum-nickel deposits in Shuidong District of Nayong County (Guizhou Province, Southwest China) are found mainly in black shale series of Lower Cambrian Niutitang Formation, which is another Mo-Ni-rich region besides Zunyi District (Guizhou province). Our systematic study on the Mo-Ni deposits in Tangjiaba of Nayong reveals that layered coarse-grained limestones, spherical beaded limestones concretions are hosted at the lower seam of the Mo-Ni deposits. Its strong negative carbon isotope anomaly (the carbon isotope value of the coarse-grained limestones varies from ?2.148‰ to 8.223‰) is similar to that in the modern submarine black smoker chimney. The carbon in the coarse-grained limestones from black rock series of Nayong County might be deep source inorganic carbon. The seams, coarse-grained limestones, ore-bearing coarse-grained limestones and the roof and floor of the deposits are characterized by co-variation on the trace element spider diagram, showing good homology. The extraordinary enrichment of Ag, As and Sb resembles hydrothermal sedimentation. Pro-Earth's core elements Se is strongly enriched in Ni-Mo ore-bearing coarse-grained limestones. The ore-bearing rock series has an extremely low Th/U value (0.012–0.19); in the logU-logTh Cartesian Coordinates, the samples of the roof and floor of the deposits and ore-bearing coarse-grained limestones are found in the East Pacific tise; and the samples of coarse-grained limestones are found between the paleo-hydrothermal dedimentary area and the East Pacific tise. The chondrite-normalized rare earth element patterns of the Ni-Mo deposits show LREE enrichment, Ce negative anomaly, and Eu negative anomaly (which is supposed to be influenced by the deep magmatic processes in an extensional environment) resembles the rare earth element distribution patterns of the fluid and its sediments in modern submarine hydrothermal system. It proves that coarse-grained limestones is characterized by typical hydrothermal limestones, being closely related with the genesis of Mo-Ni deposits in Nayong County, which provides new evidence for hydrothermal sedimentary genesis of Mo-Ni deposit and negative carbon anomaly in the basal Cambrian on a global scale.     

Impacts of Urbanization on the Precipitation Characteristics in Guangdong Province,China

With the development of urbanization, whether precipitation characteristics in Guangdong Province, China, from 1981 to 2015 have changed are investigated using rain gauge data from 76 stations. These characteristics include annual precipitation, rainfall frequency, intense rainfall(defined as hourly precipitation ≥ 20 mm), light precipitation(defined as hourly precipitation ≤ 2.5 mm), and extreme rainfall(defined as hourly rainfall exceeding the 99.9 th percentile of the hourly rainfall distribu...     

Kinetics analysis of the enzymatic hydrolysis of cellulose from straw stalk

The effects of several parameters on the simultaneous saccharification and fermentation of straw stalk for ethanol fuel production were investigated on the basis of orthogonal experiments. The parameters include temperature and time of fermentation, quantity and proportion of yeast inoculation, as well as cellulase dosage. An ethanol yield of 0.183 g/g was obtained from the straw stalk pretreated with diluted acid under determined optimum conditions. These conditions were: fermentation temperature: 38℃; fermentation time: 72 h; yeast inoculation quantity: 15%; yeast inoculation proportion: 2:1; and cellulose enzyme dosage: 20 U/g. The relationship between ethanol concentration c and fermentation time t is presented as follows, c=abt/(1+bt). The rate constant k of straw stalk hydrolysis by the cellulose enzyme depends on hydrolysis time, as described by k=k1t-h. Therefore, straw stalk hydrolysis reaction by the cellulose enzyme is fractal-like.