一种坛紫菜叶状体测定新方法研究

通过一系列试验探究坛紫菜不同生物量的指标, 以期用测量叶面积的方式来替代传统测量指标. 研究了环境的光、温、湿度对于叶面积测定结果的影响, 明确其适用范围; 设计了相关性、变异系数、标准差与增量比值的试验. 结果表明, 叶面积与干重的相关性极其显著; 叶面积的变异系数最小, 均小于1%, 其标准差与增量比值也小于其他指标. 同时也表明, 在坛紫菜的实验生态研究中, 叶面积以其灵敏性、简便、精确更占优势, 其可以作为紫菜等海藻形态、育种研究的一项重要指标.     

二阶常系数线性微分方程的积分形式通解及首次积分

利用一阶线性微分方程的通解 ,导出了二阶常系数线性微分方程的积分形式通解 .研究了通解的结构 ,并给出了首次积分 .     

Bcklund transformation, non-local symmetry and exact solutions for (2+1)-dimensional variable coefficient generalized KP equations

IntroductionDuring the study of water wave, many completely iategrable models were derived, such as(1+1)-dimensional KdV equation, MKdV equation, (2+1)-dimensional KdV equation, Boussinesq equation and WBK equations etc. Many properties of these models had been researched,such as BAcklund transformation (BT), converse rules, N-soliton solutions and Painleve property etc.II--8]. In this paper, we would like to consider (2+1)-dimensional variable coefficientgeneralized KP equation which …     

A bracket power characterization of analytic spread one ideals

The main theorem characterizes, in terms of bracket powers, analytic spread one ideals in local rings. Specifically, let be regular nonunits in a local (Noetherian) ring and assume that , the integral closure of , where . Then the main result shows that for all but finitely many units in that are non-congruent modulo and for all large integers and it holds that for and not divisible by , where is the -th bracket power of . And, conversely, if there exist positive integers , , and such that has a basis such that , then has analytic spread one.

     

奇异线性模型的估计效率

在本文中，我们对奇异线性模型提出并解决参数的可估线性函数的估计效率问题。讨论了估计效率与Ｈｏｔｅｌｌｉｎｇ广义相关系数的关系，给出了估计效率的上、下界以及达到上、下界的条件。     

山西省农民家庭消费水平和结构分析

本文利用统计计量学方法对山西省农民家庭消费水平和消费结构的变化及原因进行了实证分析。建立了山西省农民人均消费的消费函数和山西省农民总消费支出与食品、衣着、住房、日用品、燃料及文化生活服务支出的关系模型，并通过模型分析解释了农民的消费结构，也为决策者提供一些有效的参考资料。     

Dielectronic recombination of Co-like tantalum

Ab initio calculation of the total dielectronic recombination (DR) rate coefficient from the ground state of Co-like tantalum is performed using the relativistic distorted-wave approximation with configuration interaction. The contributions to the total DR rate coefficients are explicitly calculated from the complexes of Ni-like tantalum: 3s²3p⁶3d_3/2³ 3d_5/2⁶ n'l', 3s²3p⁵3d¹⁰n'l', 3s3p⁶3d¹⁰n'l', 3s²3p⁶3d⁸4ln'l', 3s²3p⁵3d⁹4ln'l' and 3s3p⁶3d⁹4ln'l' with n' ≤ 25, and 3s²3p⁶3d⁸5ln'l' with n' ≤ 9. The l' and n' dependences of partial DR rate coefficients are investigated. The contributions from higher n'complexes are evaluated by a level-by-level extrapolation method. The total DR rate coefficients mainly come from the complex series 3s²3p⁶3d⁸4ln'l', 3s²3p⁵3d⁹4ln'l' and are fitted to an empirical formula with high accuracy. Comparison of the present results with those of other works shows that the previously published data underestimate significantly the DR rates of Co-like tantalum.     

光吸收介质的吸收系数与介电函数虚部的关系

讨论了相对介电函数虚部和消光系数与光吸收的关系,指出吸收系数与消光系数成正比,而吸收系数与相对介电函数虚部成正比是有条件的.     

Cooling kinetics of a granular gas of viscoelastic particles

The evolution of a granular gas of viscoelastic particles in the homogeneous cooling state is studied. The velocity distribution function of granular particles and the time dependence of the mean kinetic energy of particles (granular temperature) are found. The noticeable deviation of the distribution function from the Maxwell distribution and its non-monotonous evolution are established. The perturbation theory with respect to the small dispersion parameter is elaborated and the analytical expressions for the asymptotic time dependence of the velocity distribution function and the granular gas temperature are derived.     

Ion–ion interactions of LiPF6 and LiBF4 in propylene carbonate solutions

Self-diffusion coefficients of Li⁺ D_Li⁺, PF₆⁻ D_PF6⁻ and solvent propylene carbonate (PC) D_PC in LiPF₆−PC solutions were determined at 298 K by the pulse gradient spin echo (PGSE) NMR technique over the salt concentration range of 0.1–3.0 M (M = mol dm^– 3). The order of the diffusion coefficients was found to be D_Li⁺ < D_PF6⁻ < D_PC over the concentration range examined, and they were monotonically decreased with increasing the salt concentration. Haven ratio Λ/Λ_NMR, where Λ and Λ_NMR represent the ionic conductivity measured electrochemically and that estimated via the Nernst-Einstein equation using the diffusion coefficient, respectively, was evaluated as the measure of the ion–ion interaction in the LiPF₆–PC solutions. Though Λ/Λ_NMR values for LiPF₆-solutions decrease with increasing the salt concentration, they were greater than those for LiBF₄–PC solutions over the whole concentration range examined, which indicates that the ion pair formation ability of PF₆^– ion is weaker than that of the BF₄^– ion. The smaller value of the ionic conductivity for the highly concentrated LiPF₆–PC solution (above 2.0 M) than that of the LiBF₄-solutions can be attributed to the more rapidly increased viscosity relative to the LiBF₄-solution. Classic molecular dynamics (MD) simulations for the respective LiPF₆ and LiBF₄-solution of 0.5 and 1.0 M were also carried out based on the effective pair potentials. Diffusion coefficients, ionic conductivity and Haven ratio for these solutions were calculated from MD trajectories, and they qualitatively agree with those evaluated by experiments. Pair correlation functions g_LiO(r) (for Li⁺–O (PC) pair) and g_LiPF6(r) (for Li⁺–PF₆^– pair) or g_LiBF4(r) (for Li⁺–BF₄^– pair) revealed that the lithium ion weakly forms the contact ion pairs with PF₆^–, whilst strongly with BF₄^–, which supports the present experimental results. Moreover, the simulation results show that both anions in the contact ion pairs predominantly take the monodentate form, which is in contrast to the multidentate coordination predicted by ab initio calculation in gas phase.