排序方式： 共有31条查询结果，搜索用时 156 毫秒
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RTK(Real Time Kinematic)即实时动态GPS测量技术,又称载波相位差分技术,是以WGS-84坐标为基础的、全球通用的一种动态测量技术.RTK-GPS的出现为测量作业带来了新曙光.本文通过工程实例介绍了RTK-GPS在公路工程放样中的应用,并结合Trimble Geomatics Office公路设计... 相似文献
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松江河金矿位于夹皮沟—海沟成矿带的东南段,矿床受一韧性剪切带控制,矿体主要赋存于SN向断裂中。按矿石自然类型,可进一步划分为蚀变岩型与石英脉型。矿化类型主要为浸染状和细脉状。依据矿物共生组合、交代与穿插关系,可将松江河金矿成矿过程划分为3个阶段:黄铁矿--石英阶段、多金属硫化物--石英阶段及石英--碳酸盐阶段。研究结果表明,包裹体类型主要为气液两相包裹体及CO2三相包裹体。成矿流体均一温度范围为138℃~355℃,盐度范围为2.23%~11.60%NaCl,密度范围为0.59~0.99 g/cm3,成矿压力为64~92 MPa,成矿深度为6.45~7.88 km。主成矿阶段含CO2三相包裹体与气液两相包裹体共存,且两种类型包裹体的均一温度相近,盐度差别较大,CO2/H2O比值降低,表明成矿流体发生了以CO2逸失为特征的不混溶或沸腾,残余流体盐度升高。成矿流体的气相成分为CO2与CH4,显示出幔源的特征。综合研究表明,松江河金矿床成因类型属于中成造山型金矿。 相似文献
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在非淹水、淹水两种水分条件下模拟氮沉降变化(分别相当于氮沉降0g/(m2.a)、1g/(m2.a)、3g/(m2.a)、5g/(m2.a))对三江平原典型湿地植物小叶章生物量及其分配的影响。结果表明,不同水分状况下氮沉降均促进小叶章生物量的积累,且以N5水平下生物量增加最多(p<0.05)。小叶章各器官生物量增长程度对氮沉降的响应并不一致:非淹水条件下根生物量平均增长最大(54.5%),其次是叶(31%)、茎(19.2%);淹水条件下小叶章各部位的生物量增长更为显著,其中根生物量平均增长124.7%,叶、茎生物量分别增长62%和61.1%。氮沉降明显促进了根生物量的积累,提高根生物量的分配比例。生长季的氮沉降对于改变湿地的营养状况、刺激植物生长具有直接的生态意义。 相似文献
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Using infrared sensors to detect ice clouds in different atmospheric layers is still a challenge. The different scattering and absorption properties of longwave and shortwave infrared channels can be utilized to fulfill this purpose.In this study, the release of Suomi-NPP Cross-track Infrared Sounder(Cr IS) full spectrum resolution is used to select and pair channels from longwave(～ 15 μm) and shortwave(～4.3 μm) CO_2 absorption bands under stricter conditions, so as to better detect ice clouds. Besides, the differences of the weighting function peaks and cloud insensitive level altitudes of the paired channels are both within 50 h Pa so that the variances due to atmospheric conditions can be minimized. The training data of clear sky are determined by Visible Infrared Imaging Radiometer Suite(VIIRS) cloud mask product and used to find the linear relationship between the paired longwave and shortwave CO_2 absorption channels. From the linear relationship, the so-called cloud emission and scattering index(CESI) is derived to detect ice clouds. CESI clearly captures the center and the ice cloud features of the Super Typhoon Hato located above 415 h Pa. Moreover, the CESI distributions agree with cloud top pressure from the VIIRS in both daytime and nighttime in different atmospheric layers. 相似文献
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Submerged barriers are constructed in coastal zones for shoreline or harbor protection or to prevent the beach erosion. In the present study, the wave run-up on a vertical seawall protected by a submerged barrier is analyzed. The physical configurations include a rigid barrier and a long channel of finite depth. For linear water waves, by matching the velocity along the barrier and along the gap, the systems of linear equations about the velocity potentials are obtained. The wave run-up is further analyzed ... 相似文献
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军曹鱼营养成分的分析及评价 总被引：37，自引：1，他引：37
对军曹鱼Rachycentron canadum Linnaeus进行解剖比较、营养分析和评价，结果显示，军曹鱼的含肉率为68．7％，肌肉蛋白质含量为21．2％，氨基酸总量为65．05％；蛋氨酸为第一限制氨基酸，其中赖氨酸含量高达591mg.gN^-1，军曹鱼的不饱和脂肪酸含量为65．2％，其中二十碳五烯酸（eicosapentaenoic acid，简称EPA）和二十二碳六烯酸（docosahexenoic acid简称DHA）的含量分别为4．5％和12．0％。研究结果表明，军曹鱼含肉率高，营养质量好，有较高的营养价值和药用价值。 相似文献