Propagating PZ 90 to WGS 84 Transformation Parameters     

Yuri A. Bazlov  Viktor F. Galazin  Boris L. Kaplan  Valery G. Maksimov  Vladimir P. Rogozin 《GPS Solutions》1999,3(1):13-16

The 29^th Research Institute recently published its latest transformation parameters for WGS and PZ 90. Because these tranformation parameter estimates were derived from stations located within Russia, variance-covariance propagation was carried out to study the benefits of a better global distribution of stations. An example that includes two stations in North America is presented. The transformation improves significantly. ? 1999 John Wiley & Sons, Inc.  相似文献   

New Casing and Backfill Design for Neutron Logging Access Boreholes     

Peter T. Zawislanski  Boris Faybishenko 《Ground water》1999,37(1):33-37

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Simulations of the mean solar magnetic field during sunspot cycle 21     

N. R. Sheeley Jr.  C. R. DeVore  J. P. Boris 《Solar physics》1985,98(2):219-239

Regarding new bipolar magnetic regions as sources of flux, we have computed the evolution of the photospheric magnetic field during 1976–1984 and derived the corresponding evolution of the mean line-of-sight field as seen from Earth. We obtained a good, but imperfect, agreement between the observed mean field and the field computed for a nominal choice of flux transport parameters. Also, we determined the response of the computed mean field to variations in the transport parameters and the source properties. The results lead us to regard the mean-field evolution as a random-walk process with dissipation. New eruptions of flux produce the random walk, and together differential rotation, meridional flow (if present), and diffusion provide the dissipation. The net effect of each new source depends on its strength and orientation (relative to the strength and orientation of the mean field) and on the time elapsed before the next eruption (relative to the decay time of the field). Thus the mean field evolves principally due to the contributions of the larger sources, which produce a strong, gradually evolving field near sunspot maximum but a weak, sporadically evolving field near sunspot minimum.E. O. Hulburt Center for Space Research.Laboratory for Computational Physics.  相似文献   

Theory of the Trojan asteroids     

Boris Garfinkel 《Celestial Mechanics and Dynamical Astronomy》1980,22(3):267-287

In the previously published Parts I and II of the paper, the author has constructed a formal long-periodic solution for the case of 11 resonance in the restricted problem of three bodies to 0(m ^3/2), wherem is the small mass parameter of the system. The time-dependencet(, ,m), where is the mean synodic longitude and is related to the Jacobi constant, has been expressed by ahyperelliptic integral. It is shown here that with the approximationm=0 in the integrand, the functiont(, , 0) can be expanded in a series involving standardelliptic functions. Then the problem of inversion can be formally solved, yielding the function (t, , 0).Similarly, the normalized period (,m) of the motion can be approximated by theHagihara hyperelliptic integral (, 0), corresponding tom=0. This integral is also expanded into elliptic functions. Asymptotic forms for (, 0) are derived for 0 and for 1, corresponding to the extreme members of thetadpole branch of the family of orbits.  相似文献   

Multiple prediction using the homeomorphic-imaging technique     

Shemer Keydar  Evgeny Landa  Boris Gelchinsky  Igor Belfer 《Geophysical Prospecting》1998,46(4):423-440

A new method for predicting different kinds of multiples and peg-leg reflections in unstacked seismic data is discussed. The basis for this method is the fact that kinematic properties of multiples can be represented as a combination of kinematic properties of primary reflections. The prediction is made using a two-step process. In the first step, the values for the angle of emergence and radius of curvature of the wavefront for primary reflections from ‘multiple-generating’ interfaces are obtained. These parameters are estimated directly from unstacked data for every source point using the homeomorphic-imaging technique. The second step consists of prediction of multiples from primary reflections that satisfy a so-called ‘multiple condition’. This condition is the equality of the absolute values of the angles of emergence calculated from the first step. This method is effective even in complex media and information on the subsurface geology is not required. The parameters are estimated directly from the unstacked data and do not require any computational efforts such as in wavefield extrapolation of data.  相似文献   

Anisotropic reflection coefficients for a weak-contrast interface     

Matthias Zillmer  Dirk Gajewski  & Boris M. Kashtan 《Geophysical Journal International》1998,132(1):159-166

In this article the interaction of plane waves with a weak-contrast interface between two weakly anisotropic half-spaces is investigated. The anisotropy dealt with is of a general type. The stress–displacement vectors of the plane waves are calculated by perturbation theory. By assuming that the jump in elastic parameters and density across the interface is small, one can derive a simple expression for the R _qPqP coefficient. In cases in which the wave motion is restricted to a symmetry plane of an anisotropic medium, simple expressions for the R _qSVqSV and R _SHSH coefficients are also derived.  相似文献   

An extended Ideal Resonance Problem     

Boris Garfinkel 《Celestial Mechanics and Dynamical Astronomy》1975,12(2):203-214

An Extended Resonance Problem is defined by the Hamiltonian, $$F = B(y) + 2\mu ^2 A(y)[\sin x + \lambda (y)]^2 \mu<< 1,\lambda = O(\mu ).$$ It is noted here that the phase-plane trajectories exhibit adouble libration, enclosing two centers, for the initial conditions of motion satisfying the inequality $$1 - |\lambda |< |\alpha |< 1 + |\lambda |,$$ where α is the usualresonance parameter. A first order solution for the case of double libration is constructed here by a generalization of the procedure previously used in solving the Ideal Resonance Problem with λ=0. The solution furnishes a reference orbit for a Perturbed Ideal Problem if a double libration occurs as a result of perturbations.  相似文献   

Theory of the Trojan asteroids Part II     

Boris Garfinkel 《Celestial Mechanics and Dynamical Astronomy》1978,18(3):259-275

In the previously published (1977a) Part I of the paper, the author has constructed a formal long-periodic solution for the case of 1:1 resonance in the restricted problem of three bodies. Here the accuracy of the solution is carried fromO(m) toO(m ^3/2), wherem is the mass parameter of the system.Asymptotic approximations for the period of the motion are obtained for the case of small oscillations about the Lagrangian pointL ₄, in agreement with the classical theory, and for the vicinity of a logarithmic singularity on themean separatrix, passing throughL ₃. The regularizing function (), which removes the singularities of the Poincaré type, is extended to all orders, and the result is used to prove the periodicity of the solution.  相似文献   

Physico-chemical study of dead sea waters. III. On gypsum saturation in Dead Sea waters and their mixtures with Mediterranean Sea water     

Boris S. Krumgalz  Frank J. Millero 《Marine Chemistry》1983,13(2):127-139

Gypsum solubility in mixtures of Dead Sea and Mediterranean Sea waters at different ratios and in their concentrates obtained by evaporation simulation have been calculated using the Pitzer model as formulated by Harvie and Weare (1980). The results obtained are compared with available experimental gypsum solubility data in different natural brines, sea water, sea water concentrates and NaCl solutions. The agreement between theoretically calculated and experimental solubility values is fairly good and is within the range of scatter of the individual solubility measurements.  相似文献   

On the refutation of the brown conjecture     

Boris Garfinkel 《Celestial Mechanics and Dynamical Astronomy》1986,38(3):231-231

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