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271.
Mass-weighted symplectic forms provide a unified framework for the treatment of both finite and vanishingly small masses in
the N-body problem. These forms are introduced, compared to previous approaches, and their properties are discussed. Applications
to symplectic mappings, the definition of action-angle variables for the Kepler problem, and Hamiltonian perturbation theory
are outlined
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
272.
The differential equations which generate a general conformal mapping of a two-dimensional Riemann manifold found by Korn
and Lichtenstein are reviewed. The Korn–Lichtenstein equations subject to the integrability conditions of type vectorial Laplace–Beltrami
equations are solved for the geometry of an ellipsoid of revolution (International Reference Ellipsoid), specifically in the
function space of bivariate polynomials in terms of surface normal ellipsoidal longitude and ellipsoidal latitude. The related
coefficient constraints are collected in two corollaries. We present the constraints to the general solution of the Korn–Lichtenstein
equations which directly generates Gau?–Krüger conformal coordinates as well as the Universal Transverse Mercator Projection
(UTM) avoiding any intermediate isometric coordinate representation. Namely, the equidistant mapping of a meridian of reference
generates the constraints in question. Finally, the detailed computation of the solution is given in terms of bivariate polynomials
up to degree five with coefficients listed in closed form.
Received: 3 June 1997 / Accepted: 17 November 1997 相似文献
273.
274.
275.
小波分析若干应用模型及在测绘中的应用和展望* 总被引:1,自引:0,他引:1
小波分析是80年代中期发展起来的应用数学理论,在众多学科领域取得了广泛的应用。文中首先对小波分析的发展作了简要概述,然后介绍了小波分析在测绘中的应用,对小波分析若干与测绘相关的应用模型进行了分析和讨论,并对小波分析在测绘中的应用前景作了展望。 相似文献
276.
概述辽、金、元三代有关测绘的管理和机构,职官设置,各类测绘状况及成果,着重介绍了元代的测绘技术,发明创造及著述。 相似文献
277.
手腕骨自动识别是实现骨龄评定自动化的关键。以数字化仪采集数据为基础,研究了模式识别与模糊数学在手腕骨自动识别中的应用理论和方法。实验证明,模式识别的应用是成功的。 相似文献
278.
R. Swennen J. van der Sluys R. Hindel A. Brusselmans 《Journal of Geochemical Exploration》1998,62(1-3)
A geochemical survey of Belgium and Luxembourg was carried out as part of an international research project entitled ‘Regional geochemical mapping of Western Europe towards the year 2000'. The aim of this research was to map regional background geochemical patterns based on pristine or at least pre-industrial overbank samples and to deduce regional information on the degree of environmental pollution of floodplain and present-day river sediments. Over the entire study area (about 33,000 km2), 66 overbank sites have been sampled. Catchment areas range between 60 and 600 km2. At each site an overbank profile has been dug out in the immediate vicinity of the river and described in detail. A first composite sample was taken 5–25 cm below the surface. This sample is supposed to represent deposition over the last centuries. Human interferences in this interval are often inferable based on changed sedimentary characteristics and the presence of anthropogenic particles such as charcoal, slags and brick fragments. A second composite sample was taken at depth, usually >1.5 m below the surface over an interval of about 20 cm. In most sites, the profile characteristics allowed to assume pre-industrial or even pristine conditions for this lower overbank sample. In some profiles this was confirmed by 14C-dating and/or by the absence of anthropogenic particles. Finally, a present-day stream sediment was sampled on the site to infer the actual pollution status. After drying at 80°C, disaggregation and sieving, the <125 μm fractions of the three sediment samples were analysed by XRF for major elements and several trace elements. Lower overbank samples generally show a direct link with the geological substrate and allow to assess natural background concentrations. Results from the mapping exercise as well as from the statistical analyses display a clear contrast between the northern part of Belgium where Cenozoic unconsolidated sandy and silty formations dominate which are especially vulnerable for erosion, and the southern part of Belgium and Luxembourg where Paleozoic and Mesozoic sandstones, carbonates, marls and shales are the prevalent lithologies. Here the shales are the most intensively eroded lithologies. This is especially reflected in the element patterns of Al2O3, MgO, K2O, Ga, Ni, Rb, Sc and V which negatively correlate with SiO2. Despite the human related pollution, the geological contrast between north and south Belgium is still recognisable in the geochemical pattern of the upper overbank and present-day stream sediment samples for the above-mentioned elements. Furthermore there is a clear increase in heavy metal contents (Zn, Cd, Pb, Cu), As and in certain locations in Ba from the lower to the upper overbank sediment, as well as to the present-day stream sediment. The relative increase in element content allows to assess the degree of pollution and helps to define those drainage areas where more detailed research is needed. 相似文献
279.
地质地球化学图解的计算机绘图系统 总被引:2,自引:1,他引:1
根据目前国内外发表的常用地质地球化学图解特征,研制了一套容纳150多幅常用地质地球化学图解的绘图系统。系统界面友好,操作方面,适用性极强,具有可扩充性。 相似文献
280.
Transient electromagnetic (TEM), self-potential (SP) and geoelectrical mapping measurements were carried out at the Chernorud-Mukhor site in the Priolkhonje area on the western shore of the Lake Baikal. All measurements were made along several profiles across the main strike of the regional Primorsky fault. TEM measurements were carried out in a time range from a few tens of microseconds to several tens of milliseconds. The most important result of the 1D modelling of TEM soundings is the discovery of nearly horizontal boundaries that divide high resistive overlying and well conducting underlying rocks. The resistivity of the former is in the range from 100 Ωm to 1000 Ωm, while the resistivity of the latter varies from less than 1 Ωm to several tens of Ωm. This good conductive zone could also be verified by geoelectrical mapping using Schlumberger array (AB/2=100 m). Due to high conductivity of the underlying rocks only the upper boundary of the conductive layer could be determined by TEM soundings. A regional SP anomaly with amplitude of about −450 mV has also been observed above the low resistivity zone indicating the electron nature of its conductance. Geologically, the conductive zone is represented by a graphite-bearing layer within the region of archean rocks. Since that layer extends over a large area, it may be used as a key in studying structures and tectonics of the Priolkhonje area. A 1D TEM geoelectric section shows a wide, gently sloping syncline as a probable base structure of the Chernorud-Mukhor site. Neotectonic faults divide the syncline into vertically displaced blocks that form a wide complicated graben with a total amplitude of about 250 m. 相似文献