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31.
GPS技术日渐投入大地测量实际应用,本文详细介绍我国第一个GPS短边检定场的建立情况,介绍了使用T2000S电子经纬仪、ME—3000边频同测法及铟钢基线尺量边在短边高精度控制网测量中的特点及其能达到的精度;介绍了该检定场控制网的精度;并且就检定物中某些边长点位精度达到1mm左右是可信的;同时证明可以满足GPS检定的需要。 相似文献
32.
Sediment source tracing using environmental magnetism: A new approach with examples from Australia 总被引：1，自引：0，他引：1
G. G. Caitcheon 《水文研究》1993,7(4):349-358
Environmental magnetism can be used for sediment source tracing in situations such as stream junctions where two catchments deliver magnetically distinguishable, well combined average source mixes to a trunk stream. Consistent mineral magnetic parameter relationships show that spatially and temporally constant magnetic mineral assemblages occur along reaches of natural streams. For most of the confluence mixing situations examined it is possible to distinguish between tributaries using magnetic parameter relationships. Using these relationships, relative tributary contributions to the resultant downstream mix can be quantified. The method can be used for tracing suspended and bedload sediments so that the principal source catchments can be determined by a sequence of measurements at stream junctions along a drainage network. There is considerable potential for using this new and easily applied method for studies of sediment delivery processes and sediment movement in fluvial environments. 相似文献
33.
易门瓷厂高墙地砖厂主体车间建于残积土地基上，约三分之二的基坑地基土天然强度低，压缩性高。加固处理，通过基坑原位测试，对加固处理前、后的地基土容许承载力进行对比，检查残积土软地基加固处理效果。 相似文献
34.
Materials properties of barricade bricks for mining applications 总被引：1，自引：0，他引：1
Christopher C. Berndt Kirralee J. Rankine Nagaratnam Sivakugan 《Geotechnical and Geological Engineering》2007,25(4):449-471
Barricade bricks are fundamental to the safe operation of a mining site. Past failures have lead to loss of life and reduced
mine efficiency or even shut down. The fundamental material property that determines the operational characteristics of barricade
bricks is their permeability, which must be tailored to suit the operational environment of the mine. The ability of the barricade
to control the hydraulic pressure within a stope application is crucial for safety and economic returns. In the current work
practical barricade bricks were tested for permeability. As well, the strength and modulus of bricks were measured after being
soaked in water for either 7 or 90 days so that a measure of their engineering functionality could be determined. The primary
conclusions of this work are as follows. There was substantial deviation in permeability between bricks; however, the average
permeability of the barricade bricks was several orders of magnitude larger than the values obtained for the hydraulic fill.
This difference indicates that modelling efforts can assume that the barricade does not contribute to the pore pressure development
within the fill. Hence the drainage of the system is not related to the permeability of these bricks provided that the barricades
are built from the bricks in such a way that the construction or future migration of fines from the fill does not impede the
drainage performance.
相似文献
| Christopher C. BerndtEmail: |
35.
Generous statistical tests 总被引：1，自引：1，他引：0
T. V. Hromadka II R. J. Whitley S. B. Horton M. J. Smith J. M. Lindquist 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(1):9-12
A common statistical problem is deciding which of two possible sources, A and B, of a contaminant is most likely the actual
source. The situation considered here, based on an actual problem of polychlorinated biphenyl contamination discussed below,
is one in which the data strongly supports the hypothesis that source A is responsible. The problem approach here is twofold:
One, accurately estimating this extreme probability. Two, since the statistics involved will be used in a legal setting, estimating
the extreme probability in such a way as to be as generous as is possible toward the defendant’s claim that the other site
B could be responsible; thereby leaving little room for argument when this assertion is shown to be highly unlikely. The statistical
testing for this problem is modeled by random variables {X
i
} and the corresponding sample mean the problem considered is providing a bound ɛ for which for a given number a
0. Under the hypothesis that the random variables {X
i
} satisfy E(X
i
) ≤ μ, for some 0 < μ < 1, statistical tests are given, described as “generous”, because ɛ is maximized. The intent is to
be able to reject the hypothesis that a
0 is a value of the sample mean while eliminating any possible objections to the model distributions chosen for the {X
i
} by choosing those distributions which maximize the value of ɛ for the test used. 相似文献
36.
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38.
本文阐述了如何建立槟城二桥GPS参考站,并分析了如何选择独立施工坐标系,最后对GPS／RTK参数进行统一设置。经GPS参考站测试,测试结果表明不仅定位精度能够满足技术设计要求,而且不同机型RTK可以联合作业。 相似文献
39.
将气候预测中常用的74项环流特征量进行归一化处理后,与郑州市冬季气温进行相关普查,利用SVM(SupportVectorM ach ine)两类分类方法,同时考虑气温的年代际变化,建立郑州冬季温度距平趋势预测推理模型,并对因子个数多少和年代际变化对预测模型的影响进行了试验。试验结果表明:用25个和15个因子分别建模时,产生最优模型时样本平均Ts评分均为56%,但后者预报准确率为75%,较前者提高了10%。用20世纪50年代和60年代做试验集,效果较好,产生最优模型时的样本Ts评分和预报准确率较高;用90年代做试验集,效果较差。 相似文献
40.