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911.
Eduardo E. Alonso Sarah M. Springman Charles W. W. Ng 《Geotechnical and Geological Engineering》2008,26(6):817-826
Two large-scale “in situ” demonstration experiments and their instrumentation are described. The first test (FEBEX Experiment)
involves the hydration of a compacted bentonite barrier under the combined effect of an inner source of heat and an outer
water flow from the confining saturated granite rock. In the second case, the progressive de-saturation of Opalinus clay induced
by maintained ventilation of an unlined tunnel is analyzed. The paper shows the performance of different sensors (capacitive
cells, psychrometers, TDR’s) and a comparison of fill behaviour with modelling results. The long term performance of some
instruments could also be evaluated specially in the case of FEBEX test. Capacitive sensors provide relative humidity data
during long transient periods characterised by very large variations of suction within the bentonite. 相似文献
912.
The culture of Sertoli cells has become an indispensable resource in studying spermatogenesis. A new Sertoli cell line (POSC) that consisted predominantly of fibroblast-like cells was derived from the testis of the olive flounder Paralichthys olivaceus and sub-cultured for 48 passages. Analysis of the mtDNA COI gene partial sequence confirmed that the cell line was from P. olivaceus. Cells were optimally maintained at 25°C in DMEM/F12 medium supplemented with fetal bovine serum, basic fibroblast growth factor, and epidermal growth factor. The growth curve of POSC showed a typical “S” shape. Chromosome analysis revealed that the cell line possessed the normal P. olivaceus diploid karyotype of 2n=48t. POSC expressed dmrt1 but not vasa, which was detected using RT-PCR and sequencing. Immunocytochemistry revealed that the cells exhibited the testicular Sertoli cell marker FasL. Therefore, POSC appeared to consist of testicular Sertoli cells. Bright fluorescent signals were observed after the cells were transfected with pEGFP-N3 plasmid, with the transfection efficiency reaching 10%. This research not only offers an ideal model for further gene expression and regulation studies on P. olivaceus, but also serves as valuable material in studying fish spermatogenesis, Sertoli cell-germ cell interactions, and the mechanism of growth and development of testis. 相似文献
913.
The impact of realistic representation of sea surface temperature (SST) on the numerical simulation of track and intensity
of tropical cyclones formed over the north Indian Ocean is studied using the Weather Research and Forecast (WRF) model. We
have selected two intense tropical cyclones formed over the Bay of Bengal for studying the SST impact. Two different sets
of SSTs were used in this study: one from TRMM Microwave Imager (TMI) satellite and other is the weekly averaged Reynold’s
SST analysis from National Center for Environmental Prediction (NCEP). WRF simulations were conducted using the Reynold’s
and TMI SST as model boundary condition for the two cyclone cases selected. The TMI SST which has a better temporal and spatial
resolution showed sharper gradient when compared to the Reynold’s SST. The use of TMI SST improved the WRF cyclone intensity
prediction when compared to that using Reynold’s SST for both the cases studied. The improvements in intensity were mainly
due to the improved prediction of surface latent and sensible heat fluxes. The use of TMI SST in place of Reynold’s SST improved
cyclone track prediction for Orissa super cyclone but slightly degraded track prediction for cyclone Mala. The present modeling
study supports the well established notion that the horizontal SST gradient is one of the major driving forces for the intensification
and movement of tropical cyclones over the Indian Ocean. 相似文献
914.
The effect of compressive viscosity, thermal conductivity and radiative heat-loss functions on the gravitational instability of infinitely extended homogeneous MHD plasma has been investigated. By taking in account these parameters we developed the six-order dispersion relation for magnetohydrodynamic (MHD) waves propagating in a homogeneous and isotropic plasma. The general dispersion relation has been developed from set of linearized basic equations and solved analytically to analyse the conditions of instability and instability of self-gravitating plasma embedded in a constant magnetic field. Our result shows that the presence of viscosity and thermal conductivity in a strong magnetic field substantially modifies the fundamental Jeans criterion of gravitational instability. 相似文献
915.
"智慧警务"是"智慧城市"的重要组成部分,也是社会治安防控体系发展的必然趋势,应提高认识,积极探索和论证建设"智慧警务"的模式和方法。本文阐述了基于二三维一体化的智慧警务地理信息平台建设内容和总体框架,并详细地介绍了警用地理信息系统及智慧警务应用系统建设内容和技术路线。 相似文献
916.
Elżbieta Worobiec 《Journal of Paleolimnology》2011,45(3):311-322
I analyzed spores, pollen and organic-walled algal remains in Middle Miocene deposits that filled a paleosinkhole at Tarnów
Opolski, in the Upper Silesian Upland, Poland. Middle Triassic limestone bedrock in the study area underwent intense karstification
under relatively warm and humid climate, resulting in development of numerous sinkholes. As the corrosion reached non-karstified
marls, flowing water in the vadose zone was plugged and meteoric waters thus accumulated, leading to pond development. This
palaeobotanical study was undertaken to “reconstruct” the fossil freshwater algae community and vegetation in and around the
water body. Chlorophyta such as Botryococcus, filamentous algae from the family Zygnemataceae, mainly Mougeotia, Spirogyra and Zygnema, and desmids were important components of the algal assemblage. Most of the identified algae prefer mesotrophic to eutrophic
conditions, and are characteristic of stagnant or slow-flowing shallow water. Among the free-floating and rooted plants were
Salviniaceae/Azollaceae (probably Salvinia), Nuphar, Potamogeton, and carnivorous taxa such as Utricularia and probably Aldrovanda. The water body was surrounded by swamp vegetation composed of herbs such as Typha, Sparganium, Alismataceae and others, and riparian forests. The upper portion of the sediment section contains abundant pollen of swamp
forest taxa such as Taxodium/Glyptostrobus, Nyssa and Alnus. The paleobotanical remains from the sinkhole at Tarnów Opolski suggest it was a shallow water body that was probably prone
to rapid warming. Presence of resting cells, e.g. zygospores of Zygnemataceae and desmids, suggests that the pond may have
dried periodically. Presence of Nuphar, Utricularia and Aldrovanda pollen, however, indicates long periods with standing water. 相似文献
917.
现代地裂缝在世界许多国家普遍存在 ,已成为当今世界范围内的主要地质灾害之一。本文在详尽分析了山西榆次地裂缝的各个致灾因子的基础上 ,利用GIS技术建立了地质学意义上的专题层 ;然后采用人工神经网络技术构建出了地裂缝灾害活动性的评价模型 ,并建立了地裂缝活动性的评价系统 ,对榆次地裂缝进行了灾害活动性评价 ,为榆次市城建和国土规划等部门的正确决策提供了重要的科学依据 相似文献
918.
Anis Gasmi Cécile Gomez Hédi Zouari Antoine Masse Danielle Ducrot 《Arabian Journal of Geosciences》2016,9(20):753
The purpose of this study was to examine the efficiency of Advanced Space Borne Thermal Emission and Reflection Radiometer (ASTER) data in the discrimination of geological formations and the generation of geological map in the northern margin of the Tunisian desert. The nine ASTER bands covering the visible (VIS), near-infrared (NIR) and short-wave infrared (SWIR) spectral regions (wavelength range of 400–2500 nm) have been treated and analyzed. As a first step of data processing, crosstalk correction, resampling, orthorectification, atmospheric correction, and radiometric normalization have been applied to the ASTER radiance data. Then, to decrease the redundancy information in highly correlated bands, the principal component analysis (PCA) has been applied on the nine ASTER bands. The results of PCA allow the validation and the rectification of the lithological boundaries already published on the geologic map, and gives a new information for identifying new lithological units corresponding to superficial formations previously undiscovered. The application of a supervised classification on the principal components image using a support vector machine (SVM) algorithm shows good correlation with the reference geologic map. The overall classification accuracy is 73 % and the kappa coefficient equals to 0.71. The processing of ASTER remote sensing data set by PCA and SVM can be employed as an effective tool for geological mapping in arid regions. 相似文献
919.
潮滩沉积环境与岩相对比研究 总被引:12,自引:1,他引:12
潮滩沉积是海陆交互作用的产物,形成于海岸坡度平缓、有丰富的细粒泥沙供应,以潮流动力为主的低能海岸环境,尤以河-海作用活跃的边缘海环境最为发育。潮滩沉积以粉砂为主,由于涨落潮流往复循环,潮滩具有动力、沉积、地貌与生物群体的分带现象。因海平面涨落与波浪参与的扰动筛选,导致潮滩沉积中的粗粒沉积物含量及微地貌形态的变化。这些因素反映于潮滩沉积相中具有下列特点:粉砂与粘土质交互叠置的页状层理;原始沉积层自下向上,粒径组成逐渐变细;下部的粉砂质层具有波痕、鱼刺状或丘状的交错层理、透镜体与扰动结构,或潮水沟堆积的镶嵌沙体;上部淤泥质层中具有草根、龟裂、虫管与钙质填充物、泥砾、泥块等。将现代潮滩沉积与南京钟山北麓下三叠统的黄马青组砂页岩,以及海口马村的下更新统湛江组粘土、粉砂岩进行对比,据泥沙粒径、矿物组合与含量,盐度,特别是薄互层理,虫管与钙质填充,泥裂块,波痕与交错层理等多项对比,均具有极好的相似性,表明该两组岩层为古潮滩沉积。 相似文献
920.
华北地块北缘西段巴音诺尔公—狼山地区牙马图岩体的岩浆混合成因 总被引:3,自引:0,他引:3
华北地块北缘西段巴音诺尔公—狼山地区的牙马图岩体以二长花岗岩为主,岩体中广泛发育岩浆暗色包体,二者界线明显。包体为岩浆结构,大多数具有塑性外形,发育淬冷边、反向脉,存在多种不平衡结构和矿物组合,如斜长石环带、石英眼斑、针状磷灰石等,显示岩浆混合特征;包体的SiO2含量为48.40%~55.40%,寄主花岗岩SiO2含量为65.03%~72.85%,具有明显的SiO2含量间隔;与寄主花岗岩相比,包体的Fe、Mg、Ca、Ti含量较高;包体和寄主花岗岩的主要氧化物之间具有很好的线性关系,微量元素和稀土元素特征相似。包体和寄主花岗岩的这些地球化学特征显示出明显的岩浆混合趋势。岩相学和元素地球化学特征表明暗色包体是基性岩浆侵入到酸性岩浆淬冷的产物,牙马图岩体存在两种岩浆的混合作用。 相似文献