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121.
台湾岛以东海域束毛藻种群的组成与分布 总被引:2,自引:0,他引:2
分别对1996年5月和1997年7月台湾岛以东黑潮及邻近海域51个采样站位的87份网采浮游植物进行了分析,总结了束毛藻种群的物种构成和丰度分布特征,并初步探讨了水动力条件、温盐、营养盐及其他元素对束毛藻生长及分布的影响.结果表明,调查区的束毛藻种群由铁氏束毛藻(Trichodesmium thiebautii)、汉氏束毛藻(Trichodesmium hildebrandtii)和红海束毛藻(Trichodesmium erythraeum)组成,前者分布最为普遍,检出率100%,丰度最大.1996年5月束毛藻平均藻丝体密度为44.55伊102 filaments/m3,铁氏束毛藻占91%,在吕宋海峡密集,总体呈现西南高,东北低的分布态势.1997年7月束毛藻平均藻丝体密度为152.72伊102 filaments/m3,铁氏束毛藻占99%,除吕宋海峡外,台湾东北部海域为次高值区,总体呈现西南高,中部和东部低的分布态势.较之邻近海区结果,台湾岛以东黑潮及邻近海域的束毛藻平均藻丝体密度高于太平洋赤道热带海域、南黄海和东海陆架区、东海产卵场,低于台湾海峡西侧20 m 以浅和东海低氧区.在台湾岛以东海域,束毛藻的丰度分布由其特定的地理位置和黑潮流向所决定,高温高盐的黑潮水系利于束毛藻的增殖,束毛藻的丰度分布与 Fe、P 等化学因子的关系有待进一步寻找证据. 相似文献
122.
In the Xiangshan Bay at the east coast of China, coastal marine pollution is conspicuous and severe in recent years. As transport of the pollutants is closely related to the coastal circulation, there is a great practical significance to investigate the circulation in this area. In this work, the surface pattern and vertical profiles of Lagrangian residual velocity (LRV) were studied based on field observation data from the inner Xiangshan Bay. By tracking GPS-GPRS drifters’ trajectories, the surface LRV pattern is going out in the central deep trough and flowing inwards near the shoreside. Combined with data from two mooring stations, vertical profiles of LRV is flowing out at surface and flowing in at the bottom, consistent with the gravitational circulation induced by baroclinic effects at the estuary. However, according to the diagnostic analysis, the main mechanism driving the residual current is barotropic rather than baroclinic. The LRV equation is controlled by the tidally-averaged barotropic pressure gradient force, tidal body force and tidally-averaged turbulent stress, while the tidally-averaged baroclinic pressure gradient force is one order of magnitude less than other forces. Additionally, the tidally mean eddy viscosity coefficient which is used in the expression of tidally-averaged turbulent stress might be not adequate and requires further studies. 相似文献
123.
塔里木河下游生态输水效益的民意调查 总被引:1,自引:0,他引:1
生态保护与环境整治是塔里木河下游生态输水工程的主要目标,因此输水能否起到改善环境和推动地方经济的发展是社会各界所关注的一个热点问题。本文采用问卷调查的方法,试图真实反映生态输水工程的社会效益。结果表明:(1) 90%以上常年生活在当地的被调查者,感受到生态输水对其本人以及其生活的环境的积极影响,因此希望继续输水的人数超过82%。(2)超过76%的家庭年收入在输水后得到不同程度的增加,表明输水后环境的变化对当地经济起到了一定的促进作用。(3)从当地居民对输水工程的继续开展的支付意愿看,70%以上的居民都表现出愿意出劳动力的强烈愿望;愿意出钱的比例为15%,两者都愿意支付的比例为6%左右。这一方面说明当地居民对继续输水的强烈渴望,也说明恢复环境的支付意愿是与当地的经济发展水平和个人生活水平紧密联系的。(4)从居民对环境变化明显程度的选项看,输水前后生态环境变化的明显程度依次为:风沙强度减弱﹥风沙次数减少﹥树草长势好转﹥野生动物增多﹥树草数量增加,这与环境监测的结果基本一致。总之,生态输水对当地居民生活和生态环境产生了很大影响,塔里木河下游生态输水的社会效益显著。 相似文献
124.
应用分析模型是面向专业应用领域GIS的关键模块之一,其设计和实现应具备良好的可扩展性和可移植性,从而达到软件复用、降低系统维护成本的目标。采用面向对象方法,对辽宁省鞍山市地质灾害评价预警系统中地质灾害危险性区划分析模型模块进行分析和设计,提出分别封装表达地质灾害分析模型方法的抽象类(class CModel)、描述灾害评价因子的抽象类(class CFactor),以及描述灾害分析单元格的抽象类(class CGridLayer)的设计方案,达到模块划分的“高内聚、低耦合”要求,便于模块的修改和扩展。以描述单元格的抽象类(class CGridLayer)作为模块与GIS平台的中间层,面向模块屏蔽不同GIS平台的实现细节,使得模块具备良好的可移植性。最后,以MapGIS 6.5为平台,按上述设计方案构建鞍山市地质灾害评价预警系统并投入实际应用。 相似文献
125.
三维含拓扑地质剖面三角剖分可视化研究 总被引:1,自引:0,他引:1
三维剖面是地质对象表达和地质问题分析中最基本和最常用的数据。该文分析三维复杂地质折剖面可视化存在的问题,并提出展开剖分算法。该方法保证了各点之间的水平距离与剖面拓扑关系不变,能够对由"多边形-弧段-结点"矢量结构构成的三维折剖面进行有效剖分。在此基础上实现了三维剖面的可视化,尤其合理解决了纹理映射中的纹理变形与重复接缝等问题。 相似文献
126.
印度尼西亚北苏拉威西蓝碧海峡浮游动物种类组成及分布 总被引:1,自引:0,他引:1
Based on oceanographic survey data in June 2012 in the Lembeh Strait, the zooplankton ecological characteristics such as species composition, individual abundance, dominant species and distribution were analyzed. The results showed that 183 species(including 4 sp.) had been recognized, most of them belonged to copepoda.Cnidaria followed with 43 species(including 1 sp.) were identified. The average abundance of zooplankton was(150.47±58.91) ind./m~3. As to the horizontal distribution, the abundance of the zooplankton was higher in the southern waters than in the northern waters. The dominant species in the study area were Lensia subtiloides,Sagitta enflata, Lucifer intermedius, Oikopleura rufescens, Diphyes chamissoni, Creseis acicula, Subeucalanus subcrassus, Temora discaudata, Aglaura hemistoma, Doliolum denticulatum, Canthocalanus pauper, Oikopleura longicauda and Nanomia bijuga. Zooplankton biodiversity indexes were higher in study area than previous study in the other regions. The findings from this study provide important baseline information for future research and monitoring programs. 相似文献
127.
128.
Thomas Kenkmann Alex Deutsch Klaus Thoma Matthias Ebert Michael H. Poelchau Elmar Buhl Eva-Regine Carl Andreas N. Danilewsky Georg Dresen Anja Dufresne Nathanaël Durr Lars Ehm Christian Grosse Max Gulde Nicole Güldemeister Christopher Hamann Lutz Hecht Stefan Hiermaier Tobias Hoerth Astrid Kowitz Falko Langenhorst Bernd Lexow Hanns-Peter Liermann Robert Luther Ulrich Mansfeld Dorothee Moser Manuel Raith Wolf Uwe Reimold Martin Sauer Frank Schäfer Ralf Thomas Schmitt Frank Sommer Jakob Wilk Rebecca Winkler Kai Wünnemann 《Meteoritics & planetary science》2018,53(8):1543-1568
This paper reviews major findings of the Multidisciplinary Experimental and Modeling Impact Crater Research Network (MEMIN). MEMIN is a consortium, funded from 2009 till 2017 by the German Research Foundation, and is aimed at investigating impact cratering processes by experimental and modeling approaches. The vision of this network has been to comprehensively quantify impact processes by conducting a strictly controlled experimental campaign at the laboratory scale, together with a multidisciplinary analytical approach. Central to MEMIN has been the use of powerful two-stage light-gas accelerators capable of producing impact craters in the decimeter size range in solid rocks that allowed detailed spatial analyses of petrophysical, structural, and geochemical changes in target rocks and ejecta. In addition, explosive setups, membrane-driven diamond anvil cells, as well as laser irradiation and split Hopkinson pressure bar technologies have been used to study the response of minerals and rocks to shock and dynamic loading as well as high-temperature conditions. We used Seeberger sandstone, Taunus quartzite, Carrara marble, and Weibern tuff as major target rock types. In concert with the experiments we conducted mesoscale numerical simulations of shock wave propagation in heterogeneous rocks resolving the complex response of grains and pores to compressive, shear, and tensile loading and macroscale modeling of crater formation and fracturing. Major results comprise (1) projectile–target interaction, (2) various aspects of shock metamorphism with special focus on low shock pressures and effects of target porosity and water saturation, (3) crater morphologies and cratering efficiencies in various nonporous and porous lithologies, (4) in situ target damage, (5) ejecta dynamics, and (6) geophysical survey of experimental craters. 相似文献
129.
Cobetia marina is a model proteobacteria in researches on marine biofouling. Its taxonomic nomenclature has been revised many times over the past few decades. ~To better understand the role of the surface-associated lifestyle of C. marina and the phylogeny of the family Halomonadaceae, we sequenced the entire genome of C. marina JCM 21022 ~T using single molecule real-time sequencing technology(SMR~T) and performed comparative genomics and phylogenomics analyses. ~The circular chromosome was 4 176 300 bp with an average GC content of 62.44% and contained 3 611 predicted coding sequences, 72 t RNA genes, and 21 r RNA genes. ~The C. marina JCM 21022 ~T genome contained a set of crucial genes involved in surface colonization processes. ~The comparative genome analysis indicated the significant diff erences between C. marina JCM 21022 ~T and Cobetia amphilecti KMM 296(formerly named C. marina KMM 296) resulted from sequence insertions or deletions and chromosomal recombination. Despite these diff erences, pan and core genome analysis showed similar gene functions between the two strains. ~The phylogenomic study of the family Halomonadaceae is reported here for the first time. We found that the relationships were well resolved among every genera tested, including Chromohalobacter, Halomonas, Cobetia, Kushneria, Zymobacter, and Halotalea. 相似文献
130.
深入研究了两种增强型AlGaN/GaN高电子迁移率晶体管(HEMT)高温退火前后的直流特性变化.槽栅增强型AlGaN/GaN HEMT在500 ℃ N2中退火5 min后,阈值电压由0.12 V正向移动到0.57 V,器件Schottky反向栅漏电流减小一个数量级.F注入增强型AlGaN/GaN HEMT在 400 ℃ N2中退火2 min后,器件阈值电压由0.23 V负向移动到-0.69 V,栅泄漏电流明显增大.槽栅增强型器件退火过程中Schottky有效势垒 相似文献