Transparent exopolymer particles (TEP) in aquatic environments   总被引：7，自引：0，他引：7  

U. Passow   《Progress in Oceanography》2002,55(3-4)

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基于偏好融合的群组推荐研究     

汪祥舜  郑孝遥  朱德义  章玥  孙丽萍 《南京气象学院学报》2019,11(5):601-608

传统的推荐系统主要针对单个用户,但随着社会和电子商务的快速发展,人们越来越多地以多个用户的形式一起参与活动,而群组推荐旨在为多个用户组成的群组提供服务,已成为当前研究的热点之一.针对目前群组推荐准确率低,群组成员之间偏好冲突难以融合的问题,本文提出了一种新的共识模型策略,融合了群组领袖影响因子和项目热度影响因子,基于K近邻为目标群组寻找邻居群组,借鉴邻居群组的偏好,设计了基于偏好融合的群组推荐算法.在MovieLens数据集上的实验结果表明,本文所提的融合策略较传统的偏好融合策略有着更优越的表现,推荐准确率（nDCG）的总体平均性能约提高13%,推荐列表多样性指标的总体平均性能约提高10%.  相似文献   

Distribution and segregation of trace elements during the growth of ore mineral crystals in hydrothermal systems: geochemical and mineralogical implications     

V.L. Tauson  S.V. Lipko  N.V. Smagunov  R.G. Kravtsova  K.Yu. Arsent’ev 《Russian Geology and Geophysics》2018,59(12):1718-1732

The interfacial crystal layer of poorly soluble mineral grown under hydrothermal conditions is modified chemically into a surficial nonautonomous phase (SNAP) and, in this capacity, takes part in growth process, doing several important functions. This paper considers some of them related to geochemistry and mineralogy. The new interpretation is given to the following phenomena: (1) selection of components during crystal growth in multiphase associations; (2) stability of multiphase parageneses having a common chemical component; (3) dual character of the distribution coefficients due to different properties of the crystal volume and SNAP; (4) formation of nano- and microinclusions of unusual composition different from the basic mineral phase; (5) spatial ordering of nano- and microparticles during their directed aggregation at the growing crystal face; (6) accumulation of valuable components (primarily noble metals), incompatible in most of mineral matrixes, in the surficial layer; and (7) effect of “hidden” metal content, associated with the presence of noble metals in the SNAP or of nano- and microinclusions formed during the SNAP evolution.  相似文献   

基于分形维数的湖州旅游景区系统空间结构优化研究   总被引：4，自引：1，他引：3  

崔大树  孙杨 《地理科学》2011,31(3):337-343

中小城市旅游业空间结构的优化及其与更大空间范围的旅游资源进行整合、衔接,是目前非中心旅游地区旅游资源开发和旅游业空间结构优化的难点。运用分形理论对湖州市旅游景区系统空间结构优化进行研究,聚集维数的测算显示湖州景区系统的空间分布聚集性较强,关联维数的测算结果显示其具有多分形特征。据此,湖州市旅游景区系统空间结构的优化主要为两个方面,即完善"两核心三组团"的旅游空间结构;加强"点—轴—面"交通体系建设,促进湖州接轨长三角地区旅游系统。  相似文献   

消石灰对膨胀土团粒化作用的研究   总被引：4，自引：2，他引：2  

程钰  石名磊  周正明 《岩土力学》2008,29(8):2209-2214

用消石灰作为外掺剂,进行了两种不同的膨胀土的对比试验。研究了不同灰剂量和龄期对膨胀土“团粒化”作用效果的影响。对于消石灰改性膨胀土而言,不同性质膨胀土界限含水率的改性效果不尽相同。强膨胀土的改性效果相对较为明显,而弱膨胀土的改性效果相对较差,其改性效果存在一个下限。在膨胀土路基的施工中,二次掺灰工艺的闷料周期可以相对缩短。这样不仅有利于加快施工进度,同时对提高石灰改良土碾压质量和加固效果十分有利。  相似文献   

Assessing the impact of land use change on hydrology by ensemble modelling (LUCHEM) IV: Model sensitivity to data aggregation and spatial (re-)distribution     

H. Bormann  L. Breuer  T. Gräff  J.A. Huisman  B. Croke 《Advances in water resources》2009

This paper analyses the effect of spatial resolution and distribution of model input data on the results of regional-scale land use scenarios using three different hydrological catchment models. A 25 m resolution data set of a mesoscale catchment and three land use scenarios are used. Data are systematically aggregated to resolutions up to 2 km. Land use scenarios are spatially redistributed, both randomly and topography based. Using these data, water fluxes are calculated on a daily time step for a 16 year time period without further calibration. Simulation results are used to identify grid size, distribution and model dependent scenario effects. In the case of data aggregation, all applied models react sensitively to grid size. WASIM and TOPLATS simulate constant water balances for grid sizes from 50 m to 300–500 m, SWAT is more sensitive to input data aggregation, simulating constant water balances between 50 m and 200 m grid size. The calculation of scenario effects is less robust to data aggregation. The maximum acceptable grid size reduces to 200–300 m for TOPLATS and WASIM. In case of spatial distribution, SWAT and TOPLATS are slightly sensitive to a redistribution of land use (below 1.5% for water balance terms), whereas WASIM shows almost no reaction. Because the aggregation effects were stronger than the redistribution effects, it is concluded that spatial discretisation is more important than spatial distribution. As the aggregation effect was mainly associated with a change in land use fraction, it is concluded that accuracy of data sets is much more important than a high spatial resolution.  相似文献   

Bowhead whales feed on plankton concentrated by estuarine and tidal currents in Academy Bay,Sea of Okhotsk     

Konstantin A. Rogachev  Eddy C. Carmack  Michael G.G. Foreman 《Continental Shelf Research》2008

Academy Bay in the Sea of Okhotsk is an important summertime feeding ground for pelagic-feeding Bowhead whales (Balaena mysticetus) in the western subarctic North Pacific. The present work combines satellite observations with physical (CTD, currents, tides) and biological (zooplankton sampling) measurements. Data obtained aboard the RV Lugovoe in August–September 2003 and July–August 2004 show dense populations of zooplankton (such as copepods Calanus glacialis, Pseudocalanus sp., pteropods Limacina helicina, and chaetognaths Sagitta sp.) that are concentrated by physical mechanisms within this critically important ecosystem. We show that near-bottom, cold water intrusions from the northern Sea of Okhotsk associated with the estuarine circulation advect arctic herbivorous calanoids (Calanus glacialis) and mollusks Limacina helicina into the region.  相似文献   

基于JOPENS系统的地震速报信息聚合与发布系统的设计与实现   总被引：1，自引：0，他引：1  

苏柱金  黄文辉 《华南地震》2014,(4):35-40

地震速报信息聚合与发布系统实时接收JOPENS系统产出的各种类型的地震速报信息,根据过滤策略进行分析处理,把同一地震事件但不同时间窗的速报信息聚合在一起,最后按照不同用户组的发布策略,分别以短信、电子邮件、传真和微博的方式自动对外发布。此外,系统具备对各个信息源进行实时监控并发出警报功能。  相似文献   

中国地震局地震应急响应信息服务平台设计与实现     

陈雅慧  段乙好  吴天安  李志强  刘晓雨  郑通彦  李晓丽  任静  张云芝  李华玥 《中国地震》2024,40(1):223-233

中国地震局地震应急响应信息服务平台是国家级震后各类应急产品汇聚与共享平台。平台为各级应急指挥人员提供全链条地震应急响应业务信息,为应急指挥决策提供信息支撑。平台具有地震应急服务响应等级信息服务、地震应急产品汇聚、现场灾情汇聚和应急响应工作资料支撑等功能。平台用户涉及中国地震局下属各单位,信息服务内容涉及指挥中心、地震速报、震情研判、灾情快报和现场应急。平台通过用户分组和任务分工实现业务管理和业务工作的无缝衔接,充分发挥整个地震局系统各单位的业务优势,实现各单位应急协同和业务联动,在多次重大破坏性地震应急期间迅速完成了信息的汇聚与共享,为应急处置工作的顺利开展提供了强有力的信息支撑。  相似文献   

山西前兆台网雷电预警数据入库设计及实现     

王鹏伟  张蕙  穆慧敏  程冬焱  李颖  李惠玲  郭宝仁 《山西地震》2019,(2):33-35

为有效发挥山西前兆台网雷电预警电场数据的实时性、实用性,基于java语言开发研制了前兆台网雷电预警入库软件。入库软件的功能主要包括雷电预警数据接收、数据转发到平台、数据格式转换并入库、雷电预警数据查询浏览等。通过该软件可以实时对台站雷电预警系统进行监控,高效分析雷电数据,加强对台站周围测点地震观测仪器的防雷保护。  相似文献