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221.
根据坐标转换参数的解算模型,介绍几种常见的坐标转换参数的求解方法及其参数个数与精度;探讨选择坐标转换参数的条件及转换参数的应用,从而阐明转换参数对GPS技术的推广和全球资料的统一的重要作用。 相似文献
222.
223.
In the Sandıklı-Afyon area, the very low-grade metamorphic Sandıklı Basement Complex with clastic sediments and Late Neoproterozoic felsic igneous rocks are unconformably overlain by a cover succession with red continental clastic rocks, tholeiitic basalts and siliciclastic rocks with Early Cambrian trace fossils. Illite crystallinity studies reveal that both the basement and cover units were metamorphosed at high anchizonal to epizonal conditions ( 300 °C). Textural data together with the detailed evaluation of the P–T–b0 grid, however, indicate that this thermal event has multiple phases. The first tectonothermal event was realized at pressures of 4.2 kb on the basis of b0-data and resulted in development of blastomylonites. This is supported by the presence of dynamo-metamorphosed pebbles within the basal conglomerates of the Lower Paleozoic cover series. The second event is post-Ordovician–pre-Jurassic in age, occurred at lower pressures 3.2 kb and produced a weakly developed cleavage in the siliciclastic rocks of the cover. The mineralogical/textural data across the basement-cover boundary therefore indicate the removal of an entire metamorphic zone and thus a metamorphic hiatus.
These data suggest that the Taurides were affected by a Late Neoproterozoic event as part of the peri-Gondwana during the Cadomian orogeny. 相似文献
224.
225.
A relativistic delay model for Earth-based very long baseline interferometry (VLBI) observation of sources at finite distances is derived. The model directly provides the VLBI delay in the scale of terrestrial time. The effect of the curved wave front is represented by using a pseudo source vector K = (R
1 + R
2)/(R
1 + R
2), and the variation of the baseline vector due to the difference of arrival time is taken into account up to the second-order by using Halley’s method. The precision of the new VLBI delay model is 1 ps for all radio sources above 100 km altitude from the Earth’s surface in Earth-based VLBI observation. Simple correction terms (parallax effect) are obtained, which can also adopt the consensus model (e.g. International Earth Rotation and Reference Frames Service conventions) to finite-distance radio source at R > 10 pc with the same precision. The new model may enable estimation of distance to the radio source directly with VLBI delay data. 相似文献
226.
本文从卫星测高数据处理中网距的选取、数据点的图形结构、网格算子等三个方面加以讨论,提出了频域中数据网格化的方法,最后利用两个周期的Topex/Poseidon卫星测高数据进行计算分析,得出了一些卫星测高数据网格化的经验。 相似文献
227.
The point source of neutral gas undergoing ionization and expanding into an uniform magnetic field is considered. Friction
between the neutral and ionized particles results in the formation of the magnetic field barrier and diamagnetic cavity surrounding
the source. At least one neutral point inevitably arises at the boundary of the cavity. When the neutral gas production rate
grows, two neutral points may arise at this boundary. In the vicinity of these points magnetic field lines converge, along
with the plasma flow which is magnetic field aligned in the steady state. As a result, two plasma jets originate from the
neutral points. Possible relation of these jets to cometary rays is discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
228.
Krzysztof Goździewski 《Celestial Mechanics and Dynamical Astronomy》1998,70(1):41-58
In this paper we consider the problem of motion of an infinitesimal point mass in the gravity field of an uniformly rotating
dumb-bell. The aim of our study is to investigate Liapunov stability of Lagrangian libration points of this problem. We analyze
the stability of libration points in the whole range of parameters ω, μ of the problem. In particular, we consider all resonance
cases when the order of resonance is not greater than five.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
229.
设D是复平面上的Jordan区域,其边界Γ∈C ̄(1+δ)。本文得到了一类在拟Fejer点上插值的复插值算子Γ在上一致收敛于f(z)∈C(Γ)的逼近阶。 相似文献
230.
G. Contopoulos H. Papadaki C. Polymilis 《Celestial Mechanics and Dynamical Astronomy》1994,60(2):249-271
We study the structure of chaos in a simple Hamiltonian system that does no have an escape energy. This system has 5 main periodic orbits that are represented on the surface of section
by the points (1)O(0,0), (2)C
1,C
2(±y
c, 0), (3)B
1,B
2(O,±1) and (4) the boundary
. The periodic orbits (1) and (4) have infinite transitions from stability (S) to instability (U) and vice-versa; the transition values of are given by simple approximate formulae. At every transitionS U a set of 4 asymptotic curves is formed atO. For larger the size and the oscillations of these curves grow until they destroy the closed invariant curves that surroundO, and they intersect the asymptotic curves of the orbitsC
1,C
2 at infinite heteroclinic points. At every transitionU S these asymptotic curves are duplicated and they start at two unstable invariant points bifurcating fromO. At the transition itself the asymptotic curves fromO are tangent to each other. The areas of the lobes fromO increase with ; these lobes increase even afterO becomes stable again. The asymptotic curves of the unstable periodic orbits follow certain rules. Whenever there are heteroclinic points the asymptotic curves of one unstable orbit approach the asymptotic curves of another unstable orbit in a definite way. Finally we study the tangencies and the spirals formed by the asymptotic curves of the orbitsB
1,B
2. We find indications that the number of spiral rotations tends to infinity as . Therefore new tangencies between the asymptotic curves appear for arbitrarily large . As a consequence there are infinite new families of stable periodic orbits that appear for arbitrarily large . 相似文献