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21.
一个载水预报模式的业务预报应用试验 总被引:8,自引:3,他引:5
该文在国家气象中心现行有限区域业务预报模式(LAM)的基础上,把模式的水平分辨率由1°×1°提高到0.5°×0.5°经纬度网格,垂直层次由15层变为20层。在原有物理过程中引入显式降水方案,并使用HLAFS业务系统的实时资料对1997年8月的一次登陆台风造成的强降水过程进行了个例预报试验,取得了较为合理的预报效果。 相似文献
22.
针对无人机倾斜摄影数据的不同处理软件空三加密 总被引:1,自引:0,他引:1
以山西省右玉县杀虎口古长城为例,采用Trimble UX5 HP搭载Sony A7r相机完成数据采集,利用Context Capture软件和PhotoMesh软件进行三维重建,并利用Geomagics软件对三维模型进行精细处理,比较两种软件的空三精度,得出Context Capture软件的空三精度更高。同时利用外业实测检查点对模型进行精度计算,得到Context Capture软件的模型精度,其点位中误差为0.192 m,表明这种方法可以满足实景三维建立模型的要求,为智慧城市的建设提供了强有力的数据保障。 相似文献
23.
John Allen 《Geoforum》2008,39(4):1613-1624
Power seems to occupy an understated role in much pragmatist thought, both classical and contemporary. It is clearly a blind spot in Richard Rorty’s work, although it is ever present in the background, and for John Dewey and William James it often appears as indistinguishable from the power to act or intervene in events so as to make a difference. In this paper, I want to push a practical account of power a step further by drawing out its expedient, anti-foundational character and its Dewey-style grounding in experience. I also try to show how the power to make a difference may just as easily be transformed into the powers of imposition and constraint, where one side gains at the expense of another. Following that, I draw out a more provisional sense of power based upon the difference that space and spatiality make to what pragmatists have traditionally referred to as the contextuality and contingency of events. This is tentatively explored by a consideration of what spatial experiments with power might look like when employed to bring about change and make a difference in the world. 相似文献
24.
Effect of mooring-line stiffness on the performance of a dual coaxial-cylinder Wave-Energy Converter
A point-absorber-type Wave-Energy Converter (WEC) consisting of a floating vertical inner cylinder and an annular outer cylinder that slides along the inner one is considered. The two cylinders heave differently under wave excitation, and wave energy can be harnessed from the relative heave motion between the two cylinders using a Permanent Magnet Linear Generator (PMLG) as the Power Take-Off unit. A mooring cable is attached to the bottom of the inner cylinder. This paper aims to examine the effect of the stiffness of the mooring cable on the performance of the coaxial-cylinder WEC system. The two limiting cases of no mooring cable (freely floating inner and outer cylinders) and an infinitely stiff mooring cable (fixed inner cylinder) were also considered. To perform the analysis, hydrodynamic and interference coefficients of the two heaving cylinders were computed semi-analytically using the method of matched eigenfunction expansions. Experimentally determined viscous corrections on damping were also included in the model in order to have more realistic predictions. The performance of the system in terms of motion responses and capture width were predicted and discussed for both regular and irregular waves. The results of the analysis indicate that both the freely floating design and the design with rigidly moored inner cylinder are viable. The two limiting cases show similar optimal performances, albeit with very different optimal generator damping. However, an ill-chosen mooring-cable stiffness may cause the inner and the outer cylinders to have the same resonance frequency, eliminating the relative heave motion and leading to almost no energy extraction. This situation needs to be avoided when designing the mooring system for a coaxial-cylinder WEC. 相似文献
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根据伪码捕获系统的工作原理,建立了描述伪码捕获过程的数学模型。在此基础上详细分析了捕获性能并导出了完成捕获过程所需的步数,提出了缩短捕获时间的办法。本文还用计算机对捕获过程进行了模拟,模拟测试结果和理论分析结果相当吻合。 相似文献
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脉冲中子伽马能谱测井是利用多探测器获取非弹性散射伽马、热中子俘获伽马能谱及伽马时间谱,通过C/O和地层宏观吸收截面来确定饱和度,但俘获伽马能谱的信息没有得到很好利用,在地层水矿化度较高的情况下,由于俘获伽马能谱的Si,Ca和H的能窗内总的伽马计数与Fe能窗内的伽马计数比值与含氯量有关,因此由俘获伽马能谱确定含水饱和度是可行的,利用MCNP(蒙特卡罗方法)模拟研究了三能窗计数与Fe能窗计数比值与饱和度、岩性、孔隙度、泥质含量、井眼持水率、地层水矿化度以及井眼套管等条件下的关系,为在高矿化度地区利用俘获伽马能谱确定饱和度的可行性在理论上提供了支持. 相似文献
29.
The aim of this paper is to compare the criteria for eco-labeling of wild-caught fish in the Norwegian eco-certified fisheries, and to study if these eco-labels affect the harvesting patterns of Norwegian fishermen. The eco-labels Marine Stewardship Council (MSC), KRAV and Friend of the Sea (FOS) as applied in 2009 were studied. In this study, the harvesting patterns are defined by using the following parameters: season, catch area, size of fishing vessel, gear type, bycatch, location of landing site and distance to the fishing ground. KRAV had more specific criteria than did MSC and FOS in specific fisheries regarding time of the fishing effort, catch area, size of fishing vessels, gear type (e.g. hook size, and the use of beam trawlers was not permitted) and distance to the fishing ground. The findings show that few of the eco-label requirements influenced these aspects in Norwegian fisheries. 相似文献
30.
为确定晚中新世红河海底扇物源区以及“红河袭夺”事件,对钻遇红河海底扇的C2井中的53颗锆石颗粒进行了SHRIMP U-Pb年龄的测定。结果表明,该扇体碎屑锆石存在6个年龄段:230~300Ma,400~500Ma,700~1000Ma,1700~1900Ma,2400~2500Ma和~2700Ma。研究结果表明,红河海底扇碎屑锆石年龄频谱特征与红河最为相似,230~300Ma的锆石主要来自呵叻高原-昆嵩地块;400~500Ma、1700~1900Ma的锆石主要来自松潘甘孜地块;700~1000Ma的锆石来自扬子克拉通;2400~2500Ma和~2700Ma的锆石主要来自松潘甘孜地块古老的扬子克拉通的基底;年龄为400~500Ma、1700~1900Ma以及大于2.4Ga的锆石说明了古红河源头曾经延伸至松潘-甘孜地区,红河袭夺现象确实存在。红河物源的存在,为在琼东南盆地深水区中央峡谷水道实施油气勘探提供了重要的理论基础。 相似文献