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1.
Ciliated protozoans represent useful organisms for studying the processes involved in the induction and progression of meiosis. In this short report we describe a technique that has allowed us to examine different meiosis phases during the sexual reproduction of Blepharisma japonicum. In order to visualize the phases of meiosis, sexually reproducing pairs were stained by an enhanced technique of anti-tubuline indirect immunofluorescence. Meiotic micronuclei, particularly those showing metaphase spindles, were clearly highlighted. The technique also heavily decorates the main microtubular cytoplasmic arrays in Blepharisma.  相似文献   

2.
刘洪伟 《物理学报》2014,63(5):50201-050201
研究广义Hamilton系统在无限小变换下的共形不变性与Mei对称性,给出系统共形不变性同时是Mei对称性的充分必要条件,得到广义Hamilton系统共形不变性导致的Mei守恒量,举例说明结果的应用.  相似文献   

3.
张克军  方建会  李燕 《中国物理 B》2011,20(5):54501-054501
Based on the concept of discrete adiabatic invariant,this paper studies the perturbation to Mei symmetry and Mei adiabatic invariants of the discrete generalized Birkhoffian system.The discrete Mei exact invariant induced from the Mei symmetry of the system without perturbation is given.The criterion of the perturbation to Mei symmetry is established and the discrete Mei adiabatic invariant induced from the perturbation to Mei symmetry is obtained.Meanwhile,an example is discussed to illustrate the application of the results.  相似文献   

4.
广义经典力学系统的对称性与Mei守恒量   总被引:4,自引:0,他引:4       下载免费PDF全文
张毅 《物理学报》2005,54(7):2980-2984
研究广义经典力学系统的对称性和一类新型守恒量——Mei守恒量.在高维增广相空间中建立 了系统的运动微分方程;给出了系统的Mei对称性、Noether对称性和Lie对称性的判据;得 到了分别由三种对称性导致Mei守恒量的条件和Mei守恒量的形式.举例说明结果的应用. 关键词: 广义经典力学 Mei对称性 Noether对称性 Lie对称性 守恒量  相似文献   

5.
黄卫立 《物理学报》2015,64(17):170202-170202
动力学逆问题是星际航行学、火箭动力学、规划运动学理论的基本问题. Mei对称性是力学系统的动力学函数在群的无限小变换下仍然满足系统原来的运动微分方程的一种新的不变性. 本文研究广义坐标下一般完整系统的Mei对称性以及与Mei对称性相关的动力学逆问题. 首先, 给出系统动力学正问题的提法和解法. 引入时间和广义坐标的无限小单参数变换群, 得到无限小生成元向量及其一次扩展. 讨论由n个广义坐标确定的一般完整力学系统的运动微分方程, 将其Lagrange函数和非势广义力作无限小变换, 给出系统运动微分方程的Mei对称性定义, 在忽略无限小变换的高阶小量的情况下得到Mei对称性的确定方程, 借助规范函数满足的结构方程导出系统Mei对称性导致的Noether守恒量. 其次, 研究系统Mei对称性的逆问题. Mei对称性的逆问题的提法是: 由已知守恒量来求相应的Mei对称性. 采取的方法是将已知积分当作由Mei对称性导致的Noether守恒量, 由Noether逆定理得到无限小变换的生成元, 再由确定方程来判断所得生成元是否为Mei对称性的. 然后, 讨论生成元变化对各种对称性的影响. 结果表明, 生成元变化对Noether和Lie对称性没有影响, 对Mei 对称性有影响, 但在调整规范函数时, 若满足一定条件, 生成元变化对Mei对称性也可以没有影响. 最后, 举例说明结果的应用.  相似文献   

6.
The Mei symmetry and conserved quantity of general discrete holonomic system are investigated in this paper. The requirement for an invariant formalism of discrete motion equations is defined to be Mei symmetry. The criterion when a conserved quantity may be obtained from Mei symmetry is also deduced. An example is discussed for applications of the results.  相似文献   

7.
In this paper, a new type of conserved quantity directly deduced from the Mei symmetry for relativistic variable mass system in phase space is studied. The definition and the criterion of the Mei symmetry for the system are given. The conditions for existence and the form of the new conserved quantity are obtained. Finally, an example is given to illustrate the application of the results.  相似文献   

8.
In this paper Mei symmetry is introduced for a nonconservative system. The necessary and sufficient condition for a Mei symmetry to be also a Lie symmetry is derived. It is proved that the Mei symmetry leads to a non-Noether conservative quantity via a Lie symmetry, and deduces a Lutzky conservative quantity via a Lie point symmetry.  相似文献   

9.
方建会  张斌  张伟伟  徐瑞莉 《中国物理 B》2012,21(5):50202-050202
In this paper,we investigate whether the Lie symmetry can induce the Mei conserved quantity directly in a nonconservative Hamilton system and a theorem is presented.The condition under which the Lie symmetry of the system directly induces the Mei conserved quantity is given.Meanwhile,an example is discussed to illustrate the application of the results.The present results have shown that the Lie symmetry of a nonconservative Hamilton system can also induce the Mei conserved quantity directly.  相似文献   

10.
In this paper, a new type of conserved quantity induced directly from the Mei symmetry for a relativistic nonholonomic mechanical system in phase space is studied. The definition and the criterion of the Mei symmetry for the system are given. The conditions for the existence and form of the new conserved quantity are obtained. Finally, an example is given to illustrate the application of the result.  相似文献   

11.
饲料中的蛋白含量,是衡量饲料优劣的主要指标,而决定饲料蛋白含量高低的主要因素包括:菌体蛋白含量(酵母菌、乳酸菌等)及饲草中自身蛋白含量;其中饲料酵母菌株蛋白含量直接决定了饲料蛋白的含量,因此获得优良的饲料酵母菌株成为关键。本研究利用辐射能量为80 MeV/u的12C6+重离子束对出发饲料酵母菌种NJ3236 (蛋白质量分数为40.64%)进行辐照诱变,并对辐照后的菌种进行初筛、复筛得到高蛋白含量菌株100G-2,该菌株较NJ3236蛋白含量提高了10.08%。利用响应面分析法对发酵培养基进行优化,通过优化得到的培养基的最优配比为:甜高粱汁20.95 g/L、玉米浆干粉18.17 g/L、硫酸镁1.60 g/L,在此条件下可溶性蛋白浓度达到1.381 mg/mL,较未优化前可溶性蛋白提高了8.7%。  相似文献   

12.
利用自由能方法的分子动力学模拟,计算了零压下Al的熔化温度.在计算液相自由能的过程中,采用勒纳-琼斯(LJ)液体作为参考系统,同时将计算结果与Mei和Davenport等人的计算结果进行了比较,计算结果表明:1)选用LJ参考系统使液相自由能的计算时间节省一半,并且不影响熔化温度的计算结果;2)采用不同的埋入原子势(EAM)的分子动力学模拟计算得到的熔化温度与实验值都存在偏差,而就金属Al而言,采用Cai等人的EAM势的熔化温度的计算结果比Mei和Davenport及Morris等人采用的势模型的结果略有改 关键词: 熔化温度 自由能方法 分子动力学模拟  相似文献   

13.
For a perturbed mechanical system in phase space, considering d/dt in the structure equation and process of proof including infinitesimal parameter ε obviously, this paper studies the perturbation to Mei symmetry and adiabatic invariants. Firstly, the exact invariant induced directly from the Mei symmetry of the system without perturbation is given. Secondly, based on the concept of high-order adiabatic invariant, the determining equations of the perturbation to Mei symmetry are established, the condition of existence of the Mei adiabatic invariant led by the perturbation to Mei symmetry is obtained, and its form is presented. Lastly, an example is given to illustrate the application of the results.  相似文献   

14.
二维运动电荷的Mei对称性   总被引:2,自引:0,他引:2       下载免费PDF全文
楼智美 《物理学报》2005,54(3):1015-1017
把Mei对称性方法用于电磁场中带电粒子的运动,从二维运动电荷的Mei对称性出发,运用比较系数法,得到与Mei对称性相应的生成元的普遍表达式及电磁场所满足的偏微分方程组.对一特例进行了讨论. 关键词: 二维运动电荷 电磁场 Mei对称性  相似文献   

15.
贾利群  罗绍凯  张耀宇 《物理学报》2007,56(11):6188-6193
研究事件空间中单面非Chetaev型非完整系统的Mei对称性和Mei守恒量.建立系统的运动微分方程,给出系统Mei对称性、弱Mei对称性、强Mei对称性的定义和判据,得到系统Mei守恒量的存在条件以及Mei守恒量的表达式.举例说明结论的应用.  相似文献   

16.
Structural equations and Mei conserved quantity of Mei symmetry for Appell equations in a holonomic system with redundant coordinates are studied. Some aspects, including the differential equations of motion, the definition and the criterion of Mei symmetry, the form of structural equations and Mei conserved quantity of Mei symmetry of Appell equations for a holonomic system with redundant coordinates, are also investigated. Finally, an example is given to illustrate the application of the results.  相似文献   

17.
研究Lagrange系统Mei对称性的Ⅲ型结构方程和Ⅲ型Mei守恒量.在群的无限小变换下,由Lagrange系统Mei对称性的定义和判据,得到Lagrange系统Mei对称性的Ⅲ型结构方程和Ⅲ型Mei守恒量.举例说明结果的应用.  相似文献   

18.
丁宁  方建会 《中国物理 B》2008,17(5):1550-1553
Based on the concept of adiabatic invariant, this paper studies the perturbation to Mei symmetry and adiabatic invariants for Hamilton systems. The exact invariants of Mei symmetry for the system without perturbation are given. The perturbation to Mei symmetry is discussed and the adiabatic invariants induced from the perturbation to Mei symmetry of the system are obtained.  相似文献   

19.
张美玲  王肖肖  韩月林  贾利群 《中国物理 B》2012,21(10):100203-100203
Mei symmetry and Mei conserved quantity of Appell equations for a variable mass holonomic system of relative motion are studied.The definition and criterion of the Mei symmetry of Appell equations for a variable mass holonomic system of relative motion under the infinitesimal transformations of groups are given.The structural equation of Mei symmetry of Appell equations and the expression of Mei conserved quantity deduced directly from Mei symmetry for a variable mass holonomic system of relative motion are gained.Finally,an example is given to illustrate the application of the results.  相似文献   

20.
赵纲领  陈立群  傅景礼  洪方昱 《中国物理 B》2013,22(3):30201-030201
In this paper,Noether symmetry and Mei symmetry of discrete nonholonomic dynamical systems with regular and the irregular lattices are investigated.Firstly,the equations of motion of discrete nonholonomic systems are introduced for regular and irregular lattices.Secondly,for cases of the two lattices,based on the invariance of the Hamiltomian functional under the infinitesimal transformation of time and generalized coordinates,we present the quasi-extremal equation,the discrete analogues of Noether identity,Noether theorems,and the Noether conservation laws of the systems.Thirdly,in cases of the two lattices,we study the Mei symmetry in which we give the discrete analogues of the criterion,the theorem,and the conservative laws of Mei symmetry for the systems.Finally,an example is discussed for the application of the results.  相似文献   

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