Unified Symmetry of Nonholonomic System of Non-Chetaev's Type in Event Space

The unified symmetry of a nonholonomic system of non-Chetaev's type in event space under infinitesimal transformations of group is studied.Firstly,the differential equations of motion of the system are given.Secondly,the definition and the criterion of the unified symmetry for the system are obtained.Thirdly,a new conserved quantity,besides the Noether conserved quantity and the Hojman conserved quantity,is deduced from the unified symmetry of a nonholonomic system of non-Chetaev's type.Finally,an example is given to illustrate the application of the result.     

Form Invariance and Conserved Quantity for Non-holonomic Systems with Variable Mass and Unilateral Constraints

The paper studies the form invariance and a type of non-Noether conserved quantity called Mei conserved quantity for non-holonomic systems with variable mass and unilateral constraints.Acoording to the invariance of the form of differential equations of motion under infinitesimal transformations,this paper gives the definition and criterion of the form invariance for non-holonomic systems with variable mass and unilateral constraints.The condition under which a form invariance can lead to Mei conservation quantity and the form of the conservation quantity are deduced.An example is given to illustrate the application of the results.     

浅议工程量清单的投标报价

工程量清单的投标报价,既要注重工程量清单的审查过程,更要掌握好在正确的计价模式下投标报价的策略,使工程既要中标,又能获取最大的利润。     

Bioinformatical study on the proteomics and evolution of SARS-CoV

A novel coronavirus has been identified as the causative agent of the severe acute respiratory syndrome (SARS). For all the SARS-CoV associated proteins derivated from the SARS-CoV genome, the physiochemical properties such as the molecular weight, isoelectric point and extinction coefficient of each protein were calculated. The transmembrane segments and subeellular localization (SubLoeation) prediction and conserved protein motifs search against database were employed to analyze the function of SARS-CoV proteins. Also, the homology protein sequence alignment and evolutionary distance matrix calculation between SARS-CoV associated proteins and the corresponding proteins of other coronaviruses were employed to identify the classification and phylogenetic relationship between SARS-CoV and other coronaviruses. The results showed that SARS-CoV is a novel coronavirus which is different from any of the three previously known groups of coronviruses, but it is closer to BoCoV and MHV than to other coronaviruses. This study is in aid of experimental determination of SARS-CoV proteomics and the development of antiviral vaccine.     

关于有心力的几点讨论

讨论2种常见类型的有心力F→=F(r)er→及F→=F(r→)er→的对称性与守恒量;并以→F=(k r2)e→r为例,引入偏心率ε→矢量或Runge-Lenz矢量。     

相空间中有二阶线性单面约束的非完整系统的Lie对称性与守恒量

研究相空间中有二阶线性单面约束的非完整系统的Lie对称性与守恒量.首先根据微分方程在无限小变换下的不变性建立Lie对称性所满足的确定方程和限制方程,给出结构方程和守恒量;其次讨论系统的Lie对称性逆问题;最后举一实例说明结果的应用.     

关于空间平移不变性的一些评注

推广了量子力学中关于对称性的分析,与对称性相关的守恒量相应地推广为含时守恒量;证明了单粒子(包括相对论情况)在静态均匀磁场和含时线性势中运动具有空间平移不变性;求出了波函数的变换关系和相应的含时守恒量.