肝炎疫情预报的数学模型与预测

对肝炎疫情进行未来预测 ,目前所采用的方法误差较大 .而且这种误差随着时间的推移而愈来愈大 .究其根本原因之一就是该系统的时变性与进行预测的数学模型参数非时变性之间存在差异 ,在对系统预测时 ,把一个时变参数的动态过程当作了非时变参数的静态过程 ,用非时变参数模型预测时变参数系统的状态 ,这必然会带来较大的误差 .为了克服上述这些缺点 ,我们给出了动态预测方法 ,其误差小 ,符合率高 ,提高了预测精度 .

财产保险收入的动态预测

为克服目前保险业发展未来预测方法中,用非时变参数模型预测时变参数系统的状态造成的较大的预测误差,将时间序列分析与数理统计分析相结合,设计了新的动态预测模型,并获得了相对于传统的预测方法较高的预测精度。该模型为与保险业相似行业的发展预测提供了新思路。

Effects of Topic Structure and Syntax on Boundary Pitch Variations

This paper reported an acoustic experiment examining the effect of topic structure and syntax on boundary pitch parameters. Simple discourses containing three sentences were constructed and the boundary between the first sentence and the second sentence of each discourse varied along the following parameters： （1） topic internal, clause; （2） topic shift, clause; （3） topic internal, sentence; and （4） topic shift, sentence. Seven native speakers of Standard Chinese read the short discourses aloud. The offset f0, f0 Max, and f0 Min of the first sentence and the onset f0, f0 Max, and f0 Min of the second sentence were measured. It was found that relative to topic internal condition, topic shift condition induced higher onset f0 following the boundary. Moreover, this higher onset f0 was caused by the raising of both f0 max and f0 min, suggesting pitch register raising rather than pitch range expansion following the boundary. Syntactic structure as index by clause or sentence was found to have no effect on boundary pitch parameters. These results provide strong evidence for a role of topic strucutre in speech production

Calibration of anisotropic yield function by introducing plane strain test instead of equi-biaxial tensile test

The equi-biaxial tensile test is often required for parameter identification of anisotropic yield function and it demands thespecial testing technique or device. Instead of the equi-biaxial tensile test, the plane strain test carried out with the traditional uniaxialtesting machine is suggested to provide the experimental data for calibration of anisotropic yield function. This simplified method byusing plane strain test was adopted to identify the parameters of Yld2000-2d yield function for 5xxx aluminum alloy and AlMgSialloy sheets. The predicted results of yield stresses, anisotropic coefficients and yield loci by the proposed method were very similarwith the experimental data and those by the equi-biaxial tensile test. It is validated that the plane strain test is effective to provideexperimental data instead of equi-biaxial tensile test for calibration of Yld2000-2d yield function.

Effect of Engineering Character on Stress-Strain Relationship in Post-Peak Area

Constitutive experiments are the base of all rock mechanics works. The effect of engineering character on constitutive law is a new problem of rock mechanics. The results of series specimens based on the uniaxial and plane strain compression experiments were presented and discussed. It is found that engineering or experiment character has obvious effects on stress-strain relationship and especially on mechanic parameters in post-peak area. And the law of size effect of softening materials was also discussed.

Study on B_d→φK_s Decay in EDQS Model

We study Bd → φKs decay in extra down-type quarks （EDQS） model with a non-universal Z boson associated with flavor changing neutral currents （FCNCs） at the tree level. With the up-to-date experimental data of Br（Bd → φKs）, SCKs, and ACKs, we derive the bounds on the Z-b-s coupling parameter ｜Ubs ｜ and the new weak phase φ, using the constrained parameter spaces, we finally give predictions for Bd → φφ decay, which could be tested at the Fermilab Tevatron and the LHC-b experiments.

Description of the shape coexistence in neutron-deficient ^(74,76)Kr with IBM2

The shape deformation and shape coexistence in ^(74,76) Kr isotopes are investigated within the framework of the proton-neutron interacting boson model(IBM2). By considering the relative energy of the d proton boson to be different from that of the neutron boson, the low-lying energy spectrum is in good agreement with experimental results both qualitatively and quantitatively. In particular, the low-lying 0_2^+ states associated with the shape-coexistence phenomenon are reproduced quite well. The calculated key sensitive quantities of B(E2) transition branch ratios are fairly consistent with the experimental data except for R_4. The predicated deformation parameter is very similar for the ground states in ^(74)Kr and ^(76)Kr, showing good agreement with the experimental result,and the calculated deformation parameter for the second 0^+ state in ^(74)Kr is close to the experimental data. The calculated results of the triaxiality parameter indicated an almost purely prolate shape for the ground state of ^(76)Kr and a mostly prolate shape with a little triaxiality for the ground state of ^(74)Kr. The calculations also show an oblate triaxial shape for the second 0^+ state in ^(76)Kr and maximum triaxiality for the second 0^+ state in ^(74)Kr. These results confirm the importance of the triaxial deformation for the description of such shape coexistence.

Semileptonic Decays B_c~*→η_cll with QCD Sum Rules

In this article, we calculate the B＊→ηc form-factors with the three-point QCD sum rules, then study the semileptonic decays B＊→ηclυl. The tiny decay widths may be observed experimentally in the future at the LHCb, while the B＊→ηc form-factors can be taken as basic input parameters in other phenomenologieal analysis.