进口铁矿砷量特征的内核密度分析与Bootstrap代表值估计

对进口铁矿中的砷量进行了总体统计分析, 在数据统计分布特征研究基础上, 使用内核密度估计对进口铁矿砷量进行数据多态性分析, 使用bootstrap对原始数据样本值重复取样以获得稳健的砷量代表值估计及标准偏差, 证明以bootstrap重新取样样本分布的均值与标准偏差作为有限单次样本代表值是合理、有效的.     

Effect of synthesis method variables on particle size in the preparation of homogeneous doped nano ZnO material

Homogeneous doped ZnO nanoparticles were synthesised by the Pechini method. A statistical experimental design was used to study the effects of the synthesis method variables on the particle size. The variables were the molar ratios of the reagents and the calcination temperature. The results indicated that the calcination temperature was the only factor that had a significant effect on the particle size. The particle size of ZnO varied between 16 and 76 nm with calcination temperatures of 400–800 °C. The homogeneity was studied by the ICP-MS technique, and the powders were found to be highly homogeneous.     

Kinetics of Polydomain Ordering at Second-Order Phase Transitions (by the Example of the AuCu<Subscript>3</Subscript> Alloy)

Kinetics of polydomain spinodal ordering is studied in alloys of AuCu₃ type. We introduce four non-conserved long-range order parameters whose sum, however, is conserved and, using the statistical approach, follow the temporal evolution of their random spatial distribution after a rapid temperature quench. A system of nonlinear differential equations for correlators of second and third order is derived. Asymptotical analysis of this system allows to investigate the scaling regime, which develops on the late stages of evolution and to extract additional information concerning the rate of decrease of the specific volume of disordered regions and the rate of decrease of the average thickness of antiphase boundaries. Comparison of these results to experimental data is given. The quench below the spinodal and the onset of long-range order may be separated by the incubation time, whose origin is different from that in first-order phase transitions. Numerical integration of equations for correlators shows also, that it is possible to prepare a sample in such a way that its further evolution will go with formation of transient kinetically slowed polydomain structures different from the final L1₂ structure.     

Alpha-induced fragmentation of 28Si in a statistical model

Within the context of a statistical model, that incorporates final-state interaction between a pair of fragments, we have calculated the energy spectra associated with the production of different isobaric pairs as a function of their lab kinetic energy and isobaric and elemental distributions of nuclei produced in the ⁴He$ + $²⁸Si reaction at cm incident energies of 102.7, 173.7, 300, 500, and 1000MeV. Double differential cross-section of isobars 16, 20, and 24 as a function of their lab kinetic energies at 30^° and the same for isobar 24 at 10^°, 30^°, 60^°, and 90^° have been calculated at cm incident energies of 102.7 and 173.7MeV and compared with the data of Woo et al. Calculated yields follow the trend of the data at each angle, and calculated angular distributions also reproduce the general trend of the observed ones. A key feature of the model is that it allows for fragments to be emitted in ground states as well as in excited states that are allowed by the conservation of energy. The analysis establishes that the fragments are emitted in excited state. The excitation energies for A = 24 and 16 are deduced from the data. The observed angular distributions for A = 7, 12, 16, 20, 24, and 28 are well accounted for assuming them to be emitted in excited states. The relative production probabilities for different elements and isobars are energy dependent. The yields for unstable elements, ⁵Li, ⁸Be, and ²⁶Al, are found to be significant. The relative fragmentation probabilities of all allowed isotopic pairs have been presented.     

Statistical equilibrium states and long-time dynamics for a transport equation

Statistical equilibrium states for a linear transport equation were defined in a previous work. We consider here the two-dimensional case: we show that under some mild assumptions these equilibrium states actually describe the long-time dynamics of the system.     

Quantum phase transition in spin glasses with multi-spin interactions

We examine the phase diagram of the p-interaction spin glass model in a transverse field. We consider a spherical version of the model and compare with results obtained in the Ising case. The analysis of the spherical model, with and without quantization, reveals a phase diagram very similar to that obtained in the Ising case. In particular, using the static approximation, reentrance is observed at low temperatures in both the quantum spherical and Ising models. This is an artifact of the approximation and disappears when the imaginary time dependence of the order parameter is taken into account. The resulting phase diagram is checked by accurate numerical investigation of the phase boundaries.     

数字地震勘探中一种统计建模及求解方法

本文提出了在数字地震勘探技术使用的一种借助于首层折射滑行波特性，来提取表层厚度、速度信息的方法。本文中介绍了该提取方法得出的过程，使用的物理模型及假设，数学原理及近似解法等。本文企盼的是，这个得出过程的启迪示范作用。     

Production of neutron-rich Ca isotopes in transfer-type reactions

The production cross sections of neutron-rich isotopes ^{52, 54, 56, 58, 60}Ca in the diffusive nucleon transfer reactions ⁴⁸Ca + ¹⁹⁷Au and ⁴⁸Ca + ²³⁸U at incident energies close to the Coulomb barrier are predicted. The global trend of production cross-section with respect to the charge (mass) number of target in reactions with ⁴⁸Ca beam is analysed for the future experiments.     

Landau diamagnetism within Tsallis thermostatistics and quantum groups

In this study, using the base of coherent states, Landau diamagnetism has been generalized within Tsallis Thermostatistics. As far as we know, this is the first attempt to introduce coherent states in this formalism. The magnetization and the susceptibility of the system have been obtained and compared with the standard result to illustrate the effect of nonextensivity. Then, adding a perturbation term to the Hamiltonian of the system, nonextensive effects on diamagnetic susceptibility have been investigated. In addition to this, making use of the -deformed partition function of the -oscillator system, the magnetization for -deformed Landau diamagnetism has been derived, with the aim of comparing the results obtained within both formalisms. Received: 21 July 1997 / Revised: 12 December 1997 / Accepted: 23 January 1998     

Sensitivity analysis in functional principal component analysis

Summary  In the present paper empirical influence functions (EIFs) are derived for eigenvalues and eigenfunctions in functional principal component analysis in both cases where the smoothing parameter is fixed and unfixed. Based on the derived influence functions a sensitivity analysis procedure is proposed for detecting jointly as well as singly influential observations. A numerical example is given to show the usefulness of the proposed procedure. In dealing with the influence on the eigenfunctions two different kinds of influence statistics are introduced. One is based on the EIF for the coefficient vectors of the basis function expansion, and the other is based on the sampled vectors of the functional EIF. Under a certain condition it can be proved both kinds of statistics provide essentially equivalent results.