1992 Vol. 17, No. 1
The direct solution of mixed boundary value problem plays an important role in the accuracy improvement of Earth's geopotential model. In this paper the authors discuss the computation method of wigner 3-j symbol and present a direct solution of mixed boundary value problem. Simulated computation results shows high accuracy of this method.
This paper deals with the effects of conservation of mass and discrepancy of cotidal charts on Loading tidal computations, and handles the spherical harmonic model of the main constituents of ocean tide.The numerical results show that it is necessary to modify schwiderski's glodal 1°×°1 cotidal data using much detailed costal cotidal data while computing ocean loading tidal effects in the mainland of China. Meanwhile, correction of mass conservation should be applied to the cotidal data The accuracy of tilt loading tide computed by means of integral technique in the inner zone and spherical harmonic expansion in the outer area is about 0.04ms.
Based on test results and calculating system of shear strength for members in bending by new code, this paper presents the calculating formulas of shear strength for composite members in bending. These formulas are easy to use, similar to test results. and join to general members in bending. By means of reliability analysis. the calculating reliabililty index β for shear strength satisfy the requirements of objective reliability index.
In this paper, a serier of structural functions are put forward based on analyse of structural principle of areal regular pattern, which proviodes the theoretical base of design of areal regular pattern on computer, and are easy to be realized and operated, The technical key of it's realization on computer is discussed.
This paper gives the methods of combining databases and discusses some corresponding problems such as geometry transformation of inputing datar into database, inlay of databases and connection of edges in HG-db3 system.It also shows some experimental results of using the method.
This paper first discusses value engineering multifactorial evaluation to optical system based on Value Engineering and Fvzzy Mathematics Mathod. Many kinds of factors are analyzed, and an evaluation model is set up in this paper. Further more, a method to determine tolerance of bias centre of a lens is enplained at the end of this paper.
There are four different tidal correction formulas. Fach of them defined a different gravity system. In this paper, the author discussed the problem of inconsistency of gravity determination results (or networks) caused by different tidal correction formulas, and calculated the effects of different tidal correction, formulas on absolute gravity determination, on relative gravity determination, on calibration of the linear constant of LCR-G meter's interval faetor, on calibration of circular errors of LCR-G meter, and on gravity determination of geophysical exploration. Also, the author analysed the inconsistency between different absolute gravity control points that used for CGBN-85 (China's gravity basic network-85), the inconsistency between CG BN-85 and china's first order gravity network Finally, on regarding the unification of our country's gravity networks, some usefull suggestions were given.
Graphic editing system is an indispensable component of graphic work station in micro-computer based Geographic Information System, which is most important for the capturing, updating and other handling of geographic data. In this paper, the author describes the prerequisites to realize a graphic editing system on the organization and structurization of cartographic data, necessary environment and interactive devices for graphic editing, etc, and introduces the system design which has been realized on micro-computer.
This paper introduces algebra operation into drawing linear symbols on maps. Symbol patterns and axes of linear elements are regarded correspondingly as two kinds of components in two-component operation so that the process of allocating patterns is independent of various symbol patterns. Namely, one process can complate nearly all the linear symbols on maps. This process is based on transformations, which simplifies the definition of the two-component operation. Finaly, a method is put forward in this paper to handle the cross of linear symbols by means of the operation.
GPS Provides a unique capability in establishing ocean bottom control network. In order to get high precision in establishing ocean bottom control network. This paper analyses simulation result, investigates various factors' influence on ocean bottom control network precision in surveying, and proves it in theory.
Let G be a simple graph on 2n vertices and k an integer satisfying -1≤k, If d(u)+d(v)≥2n+k for every two nonadjacent verfices u and v of the graph G, then G is said to be the graph of Ore-type-(k). S. Win gave the folloing conjecture:If G is the graph Ore-type-(k), then G contains k+2 disjoint 1-factors, where k≤2n-4.In this paper, we proved that Win's conjecture is tre for k=2n-4, 2u-5.