二阶微分方程解的零点分布

应用角域Nevanlinna理论和Ahlfors覆盖曲面理论, 研究了二阶微分方程f’’+A(z)f=0的解的零点分布. 证明了在复平面上至少存在一条半直线, 使得二阶微分方程解在该直线上的零点的径向收敛指数为无穷. 用新的方法证明了伍胜健在文献[5]中的一个定理.     

SiO2和ZrO2纳米粒子的极化率

The polarizabilities of ZrO_2 and SiO_2 nanoparticles were studied on the basis of hyper Rayleigh scattering measurement.It was found that the polarizability of system depended on both particle size and concentration.     

由分数次导数所确定的L2(T)中的一元周期函数类在Lq(T)中的相对宽度

作者研究了相对宽度K_n(W₂^α(T), MW₂^β(T), L₂(T)), T=[0,2π], 确定了使等式K_n(W₂^α(T), MW₂^β(T), L₂(T))=d_n(W₂^α(T), L₂(T))成立的最小M值, 得到了相对宽度K_n(W₂^α(T), W₂^α(T), L_q(T))的渐近阶, 其中α≥β>0, 1≤q≤∞, K_n(., ., L_q(T)) 和 d_n(., L_q(T))分别表示Kolmogorov意义下L_q(T)尺度下的相对宽度和宽度, MW_p^α(T), 1≤ p≤∞, 表示有如下卷积表达式的2π 周期函数类, f(t)=c+(B_α* g)(t),c∈ R, B_α*g 表示 B_α 和g 的卷积, g∈L_p(T) 满足∫₀^2πg(τ)dτ=0 和||g||_p≤M, B_α∈ L₁(T) 有如下Fourier展开: B_α(t)=1/2π∑' _{k∈ Z}(ik)^-αe^ikt,∑^'表示去掉 k=0的项.     

二重 Dirichlet级数的增长性

首先研究了双平面上二重Dirichlet级数的系数和指数与增长性之间的关系, 得到了θ 线性下级的一个充要条件, 然后在适当的条件下, 对二重Dirichlet级数所确定的整函数在双水平直线上的θ 线性级进行了估计.     

完全不确定Hamburger矩阵矩量问题的有限阶解

该文描述带有矩量序列{v_m}_0~∞■C~(q×q)的完全不确定Hamburger矩阵矩量问题:v_m=integral from n=-∞to∞x~m dρ(x),m=0,1,…的有限阶解,即该问题的那些解ρ,使得C~(q×q)-值多项式的线性空间P在对应的空间L~2(R,dρ/E(x))内稠密,这里E(x)为在实轴R上取正值的某个数值多项式.作为预备知识,作者考虑所谓广义Akhiezer插值的矩阵变种与它的相关矩阵矩量问题之间的一种关系.     

关于高阶整函数系数微分方程解的增长性的进一步结果

本文研究一类高阶整函数系数微分方程的增长性问题，当存在某个系数对方程的解的性质起主要支配作用时，得到了齐次与非齐次方程解的超级的精确估计及方程的解与小函数的关系。     

Heavy metal concentrations in soil and wild plants growing around Pb-Zn sulfide terrain in the Kohistan region, northern Pakistan

This study investigates the soil and wild plants of the Pb-Zn sulfide bearing mineralized zone of Indian plate (IP) in the Pazang and Lahor sites, Kohistan region, northern Pakistan. Soil and plants were analyzed for major cations (Na, K, Ca, Mg, Fe, Mn) and heavy metals (Pb, Zn, Cd, Cu, Cr, Ni, Co) concentrations by using atomic absorption spectrometer. Metal concentrations were used to quantify pollution contamination factors such as pollution load index (PLI) and plant bioaccumulation in soil and plants developed in mineralized zones in the Lahor and Pazang sites and an unmineralized zone (reference sites) of the Besham area. Soil and plants of the mineralized zone and surrounding areas have higher heavy metal (HM) contamination (P < 0.01) as compared to the reference site, which can be attributed to the dispersion of metals due to mining. Furthermore, in mineralized zones, the Lahor site was more contaminated than the Pazang site. This high HM contamination may pose potential threats to local communities of Kohistan region. The results also showed that plant species (Plectranthus rugosus, Rumex hastatus, Fimbristylis dichotoma, Heteropogon conturtus and Myrsine Africana) were the best HM accumulators.     

一类高阶微分方程解的增长性

本文研究了微分方程f^（k）＋Ak（z）e^ακ-^12f^（κ-1）,…,＋A0（z）e^a0z=0的增长性,其中Aj（z）（j=0,1…κ-1）是整函数,其级小于1．在αj（j=0,1,…,κ-1）满足某条件下,得到该方程的任一超越解的超级等于1的结论．     

广义Besov类Bp, θΩ在一致和随机框架下的Gel'fand逼近

该文研究了广义Besov类B_p,θ^Ω在一致和随机框架下由Gel'fand方法的逼近问题. 利用Maiorov的离散化方法和pseudo-s-scale的性质, 给出了这一逼近问题在某些情况下的渐近阶.     

On the growth of solutions of a class of higher order linear differential equations with coefficients having the same order

In this paper, the authors investigate the growth of solutions of a class of higher order linear differential equations

f(k)+Ak−1f(k−1)+?+A₀f=0