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871.
E. Iversen 《Studia Geophysica et Geodaetica》2005,49(4):525-540
This paper provides Cartesian expressions for tangent vectors of isochron rays and velocity rays previously derived in so-called
isochron-orthonormal coordinates. The Cartesian expressions are simpler and easier to implement than the expressions in isochron-orthonormal
coordinates. It is shown that the expressions in both coordinate systems are equivalent. 相似文献
872.
JIM?E.?GREENWOODEmail author VICTOR?W.?TRUESDALE ANDREW?R.?RENDELL 《Aquatic Geochemistry》2005,11(1):1-20
Summary The kinetics of phytoplankton frustule dissolution has generally been studied as the appearance of silicic acid in a batch
reactor. Unfortunately, this approach, though often illuminating, has not so far been successful because of the difficulty
of parameterising the full reaction curve. This current study shows how the initial rate approach to chemical kinetics offers
a way around this bottleneck, thereby allowing much chemical kinetics information about frustule dissolution to be collected.
The technique is shown to be flexible and suited to short reaction times which facilitate detailed quantitative kinetics investigation,
indeed, as would be expected in a solution phase, kinetics study. The technique is exemplified by a dissolution study of uncleaned
frustules of Cyclotella crypticaat 40 °C and above. The frustules were found to yield the same dissolution rate after 5 weeks dark storage, at 4 °C. Meanwhile,
log dissolution rate was found to vary linearly with pH, with gradient 0.38 ± 0.01 (r
2=0.990). Linearity was upheld even at pHs as high as 14. Finally, a robust Arrhenius plot was established between 40 and 90 °C
yielding an activation energy for dissolution of 84 ± 3 kJ mol
−1. Follow through with the Eyring equation yielded an activation enthalpy, ΔH
‡, and an activation entropy, ΔS
‡, of 81 and 85 J mol
−1 K
−1, respectively. The discussion brings salient aspects of existing knowledge about diatom frustule dissolution kinetics into
the wider context of silicate mineral dissolution. 相似文献
873.
洞室工程地震CT与VSP联合检测方法及应用实例 总被引:1,自引:0,他引:1
地震层析成像(CT)和垂直地震剖面(VSP)法一直作为两种完全分离的探测技术在勘探活动中运用,而洞室工程地震CT与VSP联合检测方法则是充分利用VSP和CT数据采集方式的兼容性,通过一体化观测系统参数设计和优化数据处理流程,将两种地震勘探手段融为一体而成为优化组合技术下的高分辨工程物探方法。方法实验结果表明,地震CT与VSP联合检测方法在近地表岩土工程勘查应用中几乎可以不增加野外工作费用,就能够同时获取地下洞室工程体施测区间内的地震CT数据和关于洞室轴向剖面方向的逆向VSP数据体。 相似文献
874.
WU Xuebao Lydie LAVANANT ZHANG Fengying RAN Maonong Pascal BRUNEL 《Acta Meteorologica Sinica》2001,15(4):477-484
This paper describes briefly the sounding capabilities of TOVS/ATOVS onboard the NOAA polar-orbiting meteorological satellites,followed by a more detailed review of the retrieval schemes.The ICI physical retrieval scheme with some adaptations is implemented in our experiment.The analyses of the Chinese regional NWP model are utilized to create a rolling library of initial guess field.Retrieval results validated against both NWP analyses and radiosondes indicate good agreement between ICI retrievals and conventional observations.Preliminary result from the PC-ATOVS Windows display system of NSMC will also be shown. 相似文献
875.
876.
In practice, rainfall–runoff relationships are achieved through a simply defined runoff coefficient concept that is widely used in many engineering hydrological designs in urban and rural areas. The simplicity of the method, with the sole requirement of runoff coefficient assessment, is the main attractiveness, in addition to its successful prediction of average runoff rates for a given rainfall record. Unfortunately, in the classical regression approach of the rainfall–runoff relationship, internal variabilities are not taken into consideration explicitly. The runoff coefficient is considered a constant value, and it is used without distinction of antecedent conditions for the calculation of runoff from the rainfall record. In this paper, various other uncertainty embedded versions of the runoff coefficient, and hence rainfall–runoff formulation, are presented in terms of statistics, probability, perturbation and, finally, fuzzy system modelling. It is concluded that the fuzzy logic approach yields the least relative error among the various alternative runoff calculation methods; therefore, it is recommended for use in future studies. The application of various alternatives is presented for two monthly rainfall‐runoff records around Istanbul, Turkey. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
877.
878.
879.
880.
The partial derivatives of travel time with respect to model parameters are referred to as perturbations. Explicit equations for the second-order and higher-order perturbations of travel time in both isotropic and anisotropic media are derived. The perturbations of travel time and its spatial derivatives can be calculated by simple numerical quadratures along rays. 相似文献