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81.
It has been argued by Jacobson, Liberati and Mattingly that synchrotron radiation from the Crab Nebula imposes a stringent constraint on any modification of the dispersion relations of the electron that might be induced by quantum gravity. We supplement their analysis by deriving the spectrum of synchrotron radiation from the coupling of an electrically charged particle to an external magnetic fields in the presence of quantum-gravity effects of the general form (E/MQG). We find that the synchrotron constraint from the Crab Nebula practically excludes 1.74 for MQGmP=1.2×1019 GeV. On the other hand, this analysis does not constrain any modification of the dispersion relation of the photon that might be induced by quantum gravity. We point out that such quantum-gravity effects need not obey the equivalence principle, a point exemplified by the Liouville-string D-particle model of space–time foam. This model suggests a linear modification of the dispersion relation for the photon, but not for the electron, and hence is compatible with known constraints from the Crab Nebula and elsewhere. 相似文献
82.
解析法是摄影测量学、数字摄影测量与遥感影像纠正处理的基础理论和基本数学模型。通过多年的教学实践,总结出了解析法摄影测量基础理论教学的两条主线,从而有效地帮助学生在学习这门课程时从其繁杂的知识体系中理清思路,找到掌握摄影测量解析法的一条捷径。 相似文献
83.
丰勇 《测绘与空间地理信息》2015,(7):199-201
根据COMPASS系统特点,通过对伪距单点定位原理的研究,设计了COMPASS系统伪距单点定位算法,验证了COMPASS系统伪距单点定位的可用性,可为北斗卫星导航定位系统在我国导航定位领域的推广应用和科学研究提供参考。 相似文献
84.
何宏 《测绘与空间地理信息》2015,(11):139-141
主要论述了网络RTK的基本原理,并针对网络RTK的几种方法进行了详尽的论述,并分析了各种方法的优缺点,为合理选用网络RTK技术提供了很好的借鉴。 相似文献
85.
介绍了建筑日照测量仪的研制原理、设计方案及使用方法.仪器通过显示器观察白天太阳周日圈上遮挡物,由编码器测量每个遮挡物所遮挡的日照时间.由于仪器采用机械装置动态模拟了日地方位角变化关系,从而保证了显示器摄像头始终沿太阳周日圈扫描(仪器专利名称;一种建筑日照测量装置,专利号:201120007301.9).对比检验表明,当采用1000脉冲编码器,通过4倍频,其分辩率为21.6s,误差在1.5 min以内.仪器结构紧凑,设计小巧,使用方便,一次常规测量只需几分钟,大大降低了测量成本,达到了现场实测、直观显示的技术要求.该仪器可用于日照纠纷仲裁,建筑日照以及气象、雷达探测环境遮挡角测量. 相似文献
86.
商标翻译的原则与方法 总被引:1,自引:0,他引:1
冯丽姣 《成都信息工程学院学报》2006,21(2):313-316
随着商品交流的不断扩大、经济全球化的深入,商标作为代表商品的符号,在国际贸易中扮演着十分重要的角色。商标的翻译也就日趋频繁。通过对一些商标译名范例的分析来探讨翻译商标的主要原则和方法。 相似文献
87.
Abstract Variational problem for irrotational, incompressible inviscid fluid in finite water depth is considered. Based on the variational principle, a special solution of the problem is presented under the assumption that the dispersion /u and the nonlinearity ?satisfied e = O(fj2) as the Lagrange function is expanded up to O(//). It is shown that the elevation of the free surface should be expanded to // order to ensure the Lagrange function is in fj* order. Comparison the nonlinear free surface profiles obtained from the solution with the corresponding ones obtained from linear solutions showed that the wave crest of the nonlinear wave is steepened but the trough is flattened compared to the linear wave as expected. 相似文献
88.
便携式潮汐观测仪(PET)数据处理研究 总被引:1,自引:0,他引:1
介绍了用切比雪夫多项式和最小二乘相结合的数据拟合从重力固体潮观测的秒值提取分钟值和小时值的方法,该方法可以将错误数据自动剔除以得到可靠数据.将提取的数据应用于调和分析,效果良好. 相似文献
89.
郭东屏 《地球科学与环境学报》1988,(3)
本文根据流体动力弥散理论,按照地下水中溶质局部质量守恒原理,采用非线性基函数,导出了求解流体动力弥散问题的一种新的数值法,即等参数溶质质量均衡有限元法。该法与采用同样非线性基函数的等参数里茨(Ritz)法或伽辽全法相比,具有物理意义明确、能准确反映局部质量均衡关系、计算公式简单和易于应用等优点。 相似文献
90.
QITI GUO 《Journal of Metamorphic Geology》1984,2(4):267-295
Multisystems of n+k (k > 3) phases are very complicated and knowledge of them has suffered as a result. The successful solution of the topological relationships in n+ 3 phase multisystems by Zen (1966, 1967) and Zen & Roseboom (1972) has aroused much interest regarding what will happen in a multisystem of more than n+ 3 phases. Since 1979, some important research results on this topic have been published. These results have expounded the substantial rules governing the appearance of phase relations in phase diagrams of n - k (k > 3) phase multisystems. The most significant conclusions include: (1) It is impossible to incorporate all the possible phase relations in an n+k (k > 3) phase multisystem in a single closed net. Therefore, it is no longer enough to use only a single closed net to depict the topological relations involved in these types of multisystems. Instead, one or more groups of closed nets, namely the complete system(s) of closed nets are necessary for this purpose. (2) A principle called the Combination Principle has been proposed and proved. It states: Any closed net of one n+k (k > 3) phase multisystem must be a combination of two or more distinct n+ 3 order submultisystem closed nets belonging to the given n+k phase multisystem, if it is not one of the n+ 3 order submultisystem closed nets itself. The combination principle provides both a theoretical basis and a practical method for the construction of closed nets and, hence, for the derivation of the real phase diagrams for any n+k (k > 3) phase multisystem. (3) A theorem on divariant-assemblage-characteristic-stability-polygons is also important to our understanding of the n+k (k± 3) phase multisystem closed nets. This theorem can be stated as follows: A divariant assemblage of an n+k (k± 3) phase multisystem will be stable in an l-polygon lacking diagonals in an appropriate set of closed-net-diagrams, and this l-polygon may be at least a triangle, and at most a k-polygon. In addition, the closed-net-diagrams of unary and binary n+ 4 phase multisystems derived respectively by Guo (1980b, 1980c, 1981a) and by Roseboom & Zen (1982) have also been summarized. The combination principle is applied to a practical petrological problem in this paper, dealing with 7 phases in the system FeO-Fe2O3-SiO2. 相似文献