Papers by Keyword: Maximum Entropy Method

Abstract: Stiffened plate is widely used in vessel structure because of its high bearing capacity and low weight so the research of failure probability for stiffened plate under explosion load has important engineering meaning. Stiffened plate under near-field explosion is taken as research subject, dynamite density and yield stress of plate are selected as random variables, the original values of one hundred groups of random variables are gotten through the random number generation program, and the moments of random variables are obtained. Based on failure criterion of displacement ductility, the performance function of structure is established, probability density function of performance function is fitted using maximum entropy method then the failure probability of stiffened plate structure is obtained. So as to solve the problem of calculate failure probability when the sample size is small and the probability density function is unknown.

Abstract: With the rapid development of economy and the speeding-up market, the extention of construction land is inevitable and the land transfer price also becomes increasingly salient. There are many factors affect the price of the land transfer. In this paper the auther constructs the price forecasting model of land transfer using maximum entropy method and finally does the price projections calculation of land transfer with engineering examples.

Abstract: The distribution of metallogenic elements grade is an effective index for the quantitatively economical evaluation of mineral resources. We have defined the information entropy as a measure of randomness of metallogenic elements grade distribution, assumed its primary distribution is in an extremely random situation, and deduced the density function of the primary distribution based on maximum entropy principle. Considering the fact that elements concentration goes from a non-orderly state to an orderly one in the ore-forming process, we added restraint parameters to the primary distribution model, got a two-parameter Weibull distribution model with embedded fractal features, and then fitted metallogenic element's grade distribution of Ag-Cu-Pb-Zn from a mine in China. The results show that the Weibull model is more effective than a lognormal model to describe elements distribution, and should be applied more broadly than common lognormal models in geology discipline.

Abstract: In this work, high vacuum (10^-6 Torr) annealed (at 500^°C) samples of the thermoelectric materials Bi₂Te₃ and Sb₂Te₃ were analyzed in terms of local structures and electron density distribution. After annealing, the samples were analyzed for their structural properties using powder X- ray diffraction data. The electron density distribution has been analyzed using the MEM (maximum entropy method) and the precise bonding in Bi₂Te₃ and Sb₂Te₃ has been determined. Since Bi₂Te₃ and Sb₂Te₃ and their combinations are the latest high figure of merit thermoelectric materials, with immediate application in many fields, particularly the electrical power harvesting devices, a study on the local structure of these materials becomes important which has been carried out in this work. Also the particle size variation due to annealing effect is studied and reported and the bond distance between neighboring atoms in bismuth telluride and antimony telluride has been analyzed.

Abstract: In this work, CdS nano particles were synthesized using aqueous precipitation method; This method is simple, fast and can be carried out at room temperature. Various techniques like X-ray powder diffraction and UV-visible absorption spectroscopy are used for the structural characterization like electron density distribution and estimation of inter atomic distances between the atoms of the nano particles. The optical band gap of this material has been determined in order to establish a relationship between energy gap of bulk and nano materials.

Abstract: In this work, lead sulphide has been characterized using X- ray diffraction, SEM, EDX and UV-Visible techniques. X-ray analysis is done by using the Rietveld refinement method of matching the observed and calculated profiles, and then the results obtained from the refinement process are used in finding the electron density distribution by using maximum entropy method (MEM). The local structure analysis of PbS is done by the pair distribution function (PDF). Particle size analysis is done with the use of XRD data, SEM analysis is done in finding the surface structure and EDX in finding the elemental composition of PbS sample. The energy gap of PbS is found from UV-Visible spectrum.

Abstract: With the thin-wall dynamic analytical model of aqueduct for fluid-structure coupling, the seismic reliability of aqueduct is studied. In this model the influence of the bend-torsion coupling, water-structure coupling and nonlinear rubber bearing isolation are all taken into consideration. Based on the type of site soil, the artificial seismic waves are created. In accordance with the maximum entropy principle and the measured data of structural internal force under earthquake, the reliability distribution function and the aqueduct reliability are calculated.