A deterministic linearized recurrent neural network for recognizing the transition of rainfall–runoff processes

Characterizing the dynamic relationship between rainfall and runoff is a highly interesting modeling problem in hydrology. This study develops a deterministic linearized recurrent neural network (denoted as DLRNN) that deals with the system’s nonlinearity by recalibration at each time interval, and relates the weights of DLRNN to unit hydrographs in order to describe the transition of the rainfall–runoff processes. Case studies of 38 events, from 1966 to 1997, are implemented in the Wu-Tu watershed of Taiwan, where the runoff path-lines are short and steep. A comparison between the DLRNN and a feed-forward neural network demonstrates the advantage of DLRNN as a dynamic system model. It is concluded that DLRNN shows superiority in the performance of rainfall–runoff simulations and the ability to recognize transitions in hydrological processes.     

Platinum and palladium abundances in floodplain sediments and their geochemical provinces

Results obtained from the wide-spaced floodplain sediments indicate that the abundances of Pt and Pd in floodplain sediments are 0.46ng/g and 0.40ng/g,respectively.Three geochemical provinces.Yunnan-Guizhou,Xinjiang-Gansu and Tibet of Pt and Pd with a content of 0.8ng/g,were delineated.     

焦石坝-武隆构造带古流体活动差异及对页岩气保存条件的影响

焦石坝-武隆地区差异构造带发育,古流体活动复杂,对页岩气保存条件影响较为关键.以两类典型背斜(高陡背斜和箱状背斜)的裂缝脉为研究对象,基于裂缝分形理论和碳、氧、锶同位素地球化学理论,揭示出不同构造的古流体活动差异与页岩气保存条件优劣的耦合性.研究认为:(1)构造变形与古流体活动性存在耦合性.构造应力集中部位(如箱状背斜枢纽、隐伏断层)较构造其他部位具更强的流体活动性.(2)古流体示踪差异与页岩气保存条件存在耦合性.同位素地球化学揭示出二叠系-下三叠统以内源流体活动为主,封闭能力较好,盆内高陡背斜带和盆外残余向斜五峰-龙马溪组页岩气具备一定勘探前景;中寒武统-下奥陶统存在跨层流体活动的痕迹,封闭能力变差,盆外箱状背斜下寒武统筇竹寺组页岩气勘探风险加大.     

基于Holland台风模型及三重嵌套海浪模式的台风浪数值模拟研究

现有的风场资料存在台风中心附近风速偏低的问题。为改进台风期间风场数据, 使用Holland经验台风模型结合多平台交叉校准数据(cross-calibrated multi-platform, CCMP)及欧洲中期天气预报中心的再分析数据(European Centre for Medium-range Weather Forecasts Reanalysis data, ERA5)风场资料, 研究了不同台风最大风速半径(maximum wind radius of the typhoon, RMW)、Holland B参数对模拟效果的影响, 确定了最优模拟参数, 并以改进后的风场驱动三重嵌套海浪模型对台风“威马逊”发生期间的台风浪进行模拟。模拟结果与实测数据对比表明, (1)改进的风场资料与实测结果更为接近, 作为海浪模式驱动项可更好地模拟台风期间波浪状况; (2)三重嵌套海浪模型的波浪模拟效果优于单独的海浪模型。     

铁山港湾生原要素的变化特征及其影响因素

本文根据1999年12月的调查资料，分析探讨了广西沿海东部东部铁山港湾生成要素的变化特征及其影响因素。结果表明：本水域生原要素含量不高，与相邻的北海湾相比略低，但与1984年岸调的结果相比，N和Si呈上升趋势，P则呈下降趋势，N以陆源输入影响为主，而P和Si则以有机体分解的再生过程影响为主。     

Research status of earthquake forecasting in hydraulicfracturing induced earthquakes

In the new types of industrial activities including unconventional energy extraction associated with shale gas and hot dry rock, gas reservoir operations, CO2 geological storage, undergoing research on induced earthquake forecasting has become one of the forward positions of current seismology. As for the intense actual demand, the immature research on induced earthquake forecasting has already been applied in pre-assessment of site safety and seismic hazard and risk management. This work will review systematically recent advances in earthquake forecasting induced by hydraulic fracturing during industrial production from four aspects: earthquake occurrence probability, maximum expected magnitude forecasting, seismic risk analysis for engineering and social applications and key scientific problems. In terms of earthquake occurrence probability, we introduce statistical forecasting models such as an improved ETAS and non-stationary ETAS and physical forecasting models such as Seismogenic Index (SI) and hydro-mechanism nucleation. Research on maximum expected magnitude forecasting has experienced four stages of linear relationship with net injection volume of fluid, power exponential relationship and physical forecasting regarding fault parameters. For seismic risk analysis, we focus on probabilistic seismic hazard assessment and quantitative geological susceptibility model. Furthermore, this review is extended to key scientific problems that contain obtaining accurate fault scale and environmental stress state of reservoir, critical physical process of runaway rupture, complex mechanism of fault activation as well as physical mechanism and modeling of trailing effect. This work in understanding induced earthquake forecasting may contribute to unconventional energy development and production, seismic hazard mitigation, emergency management and scientific research as a reference.     

Geopolymer formation and its unique properties

The characteristic property of naturally-occurring geopolymers is a high content of humic materials that are recognized by the nitrogen function. Through a simulated geopolymerization, biopolymers with non-nitrogen function, such as xanthan gum, were found to have the characteristics of humic acid by means of UV–Vis spectrometry. This fact ascertains that any kind of biopolymer may naturally transform to a geopolymer. A geopolymer is a type of crosslinked long-chain compound, built in three-dimensional structures whose property is immune to microbial degradation. A crosslinked biopolymer was shown to have the same characterization as a geopolymer that has a long life due to its crosslinking capacity and anti-microbial properties. In this study, the formation of petroleum-based geopolymers (e.g., kerogen) was introduced. This study may elucidate the structure of geomacromolecules and the mechanism of their formation, closely related with crosslink reaction between inorganic and organic molecules. This will further change the conventional definition of geopolymer that involves only the inorganic geopolymer.     

日本沼虾生理生态学研究

于１９９２年９－１０月对采自上海市的日本沼虾的代谢进行实验研究。结果表明，１温度和体重对日本沼虾的耗氧率，排氨率都有明显的影响；２。日本沼虾尿素氮的排泄量约点总排泄氮量的３８％；３。在小于和大于１．５ｇ的日本沼虾代谢底物中，蛋白质，糖和脂肪提供的能量比分别为１０．４：３９．３：５０．３和５．２：４１．５：５３．３：４。在１０，１５，２０和２５℃，日本沼虾的平均静止能耗量为１．６，２．２，３．２和５     

中华绒螯蟹幼体消化系统发育的研究

于1986，1987两年的3－6月，在浙江平湖水产试验场等地采集中华绒螯蟹五期状幼体和一期大眼幼体，对其消化系统发育的研究表明：各期幼体消化道平均全长分别为0．912mm，1．332mm，1．628mm，1．998mm，2．221mm和2．644mm；胃在Z1中呈椭圆形，到Z3方才明显分化成贲门胃和幽门胃两部分；至于贲门胃内的研磨结构和幽门胃内的滤器则要到大眼幼体才完全形成；在各期幼体中，中肠均是消化道最发达的部分肠壁细胞呈圆柱状；肝胰管和中肠前盲囊在Z1中出现，而中肠后盲囊却要到Z2方才形成。