Environmental Impacts on Spiking Properties in Hodgkin-Huxley Neuron with Direct Current Stimulus

Based on the well accepted Hodgkin-Huxley neuron model, the neuronal intrinsic excitability is studied when the neuron is subject to varying environmental temperatures, the typical impact for its regulating ways. With computer simulation, it is found that altering environmental temperature can improve or inhibit the neuronal intrinsic excitability so as to influence the neuronal spiking properties. The impacts from environmental factors can be understood that,the neuronal spiking threshold is essentially influenced by the fluctuations in the environment. With the environmental temperature varying, burst spiking is realized for the neuronal membrane voltage because of the environment-dependent spiking threshold. This burst induced by changes in spiking threshold is different from that excited by input currents or other stimulus.     

有机硅试剂参与过渡金属催化的C-H官能团化反应形成C-C键的研究进展

作为一类重要的有机金属试剂,有机硅试剂在有机合成化学的C—C键形成中得到了广泛应用.综述了近年来有机硅试剂参与的过渡金属催化下C—H官能团化反应形成C—C键的研究进展,重点介绍了Pd催化下C—H官能团化的Hiyama偶联反应.     

关于电压、电势和电势差概念的理解

文章讨论了稳定涡旋电场中导体上的电压,并把该情况及似稳条件下导体上的"电势""电势差"与静电场中的电势、电势差作了比较。结果表明:只存在静电场时,空间任一点有电势,两点间有电势差;存在涡旋电场时,在一定条件下(形成稳定电流和似稳电流时)在导体上任一点有"电势",只在由导体连接着的两点间有"电势差"。当电场为只由静止电荷激发的静电场,此时一点的电势值与零点的选择有关,电势差与积分路径无关;当电场为全部电场中的保守场部分时,一点的"电势"值与零点的选择有关,"电势差"也与积分路径无关。两点间电势差是单位正电荷从一点经任意路径移到另一点时外力克服静电力做功而增加的能量,即静电势能的增量;两点间"电势差"是单位正电荷从导体上任一点经导体中的任意路径移到另一点时获得的(净)能量,是外力所做的功除去发热剩余的能量,数值上恰等于静电势能的增量。     

如何求解立体几何中二面角的问题

空间图形的位置关系是立体几何的重要内容,解决立体几何问题的关键在于三定:定性分析→定位作图→定量计算,其中定性是定位、定量的基础,而定量是定位、定性的深化.在面面关系中,二面角是其中的重要概念之一,它的度量归结为平面上角的度量.从以往的教学中发现,学生往往把握不住其定位的基本思路而导致思维混乱,甚至错误地定其位.本文就是针对这一点,来谈一谈平日教学中的体会.     

The synchronization of FitzHugh--Nagumo neuron network coupled by gap junction

It is well known that the strong coupling can synchronize a network of nonlinear oscillators. Synchronization provides the basis of the remarkable computational performance of the brain. In this paper the FitzHugh-Nagumo neuron network is constructed. The dependence of the synchronization on the coupling strength, the noise intensity and the size of the neuron network has been discussed. The results indicate that the coupling among neurons works to improve the synchronization, and noise increases the neuron random dynamics and the local fluctuations; the larger the size of network, the worse the synchronization. The dependence of the synchronization on the strength of the electric synapse coupling and chemical synapse coupling has also been discussed, which proves that electric synapse coupling can enhance the synchronization of the neuron network largely.     

统计收敛的测度理论

建立统计收敛的测度理论已经成为统计收敛研究领域的核心问题, 因为一种合理的理论不仅是把各种统计收敛统一起来, 而且是统计收敛通向测度理论、积分理论、概率论和数理统计的桥梁. 基于这个原因, 首先 证明了由N 的所有子集生成的σ-代数$\mathscr{A}$ 上的所有有限可加概率测度的表示定理; 证明了每个有限可加概率测度都可以唯一的分解为一个可数可加概率测度和一个统计测度(即一个有限可加概率测度μ, 对任意的单 点集{k} 有μ(k)=0)的凸组合. 本文还证明了经典统计测度的许多良好性质, 例如: 由所有经典统计测度组成的集合$\mathscr{S}$ 在$\mathscr{A}$上赋予逐点收敛的拓扑就成为紧凸的~Hausdorff 空间; 每一个经典统计测度都是连续型的~(所以是缺原子的); 对N中的任意子集，每一类特殊的统计测度都满足互余极大极小原理; 每一类统计收敛都可以在统计测度的意义下得到统一.