Halin图在环面上嵌入的灵活性

In this paper we show that the face-width of any embedding of a Halin graph(a type of planar graph) in the torus is one, and give a formula for determining the number of all nonequivalent embeddings of a Halin graph in the torus.     

两类广义Petersen 图的Euler亏格

广义 Petersen 图 P(n, m) 是这样的一个图:它的顶点集是{u_i, v_i | i=0,1, ^… , n-1}, 边集是 {u_iu_i+1, v_iv_i+m, u_iv_i | i=0,1, ^…, n-1}, 这里 m, n 是正整数、加法是在模n 下且 m<|n/2| . 这篇文章证明了P(2m+1, m)(m≥ 2) 的 Euler 亏格是1, 并且 P(2m+2, m)(m≥ 5) 的 Euler 亏格是2.     

具有非局部源的快扩散方程组解的熄灭

利用上下解的方法和积分估计, 研究了一类具有非局部源的快扩散方程组解熄灭的充分条件,证明当参数和初值满足一定条件时,解在有限时刻发生熄灭．     

He2分子b3∏g(v=9)态的预解离

The predissociation of the v=9 level in the b³Π_g state by the c³∑_g⁺ state of helium eximer(He₂) was studied based on the newly observed (9, 3) band in the b³Π_g-a³∑_u⁺ system inthe region of 12065～12445 cm^-1 employing optical heterodyne-concentration modulationabsorption spectroscopy. With the help of the previous potential energy curves and molecular constants of He₂, the corresponding predissociation mechanism for the b³Π_g (v=9) state was analyzed. An RKR potential energy curve of b³Π_g and an ab initio potential curve of c³∑_g⁺ were used to calculate the predissociation linewidths that show basic agreement withobservations, which can quantitatively explain the experiments.     

EPR Technology Spectroscopic Investigation of Generation of Reactive Oxygen Species Free Radicals in Laccase-Activated Jute Fiber

Lignins in jute fibers can be activated by laccase to generate reactive oxygen species (ROS) free radicals for subsequent use in radical graft polymerization. The effect of incubation conditions on the generation of ROS free radicals when jute powders were incubated with laccase was investigated through spin-trapping technique to detect the spin adduct of N-tert-butyl-α-phenylnitrone and ROS free radical using electron paramagnetic resonance spectroscopy. Results revealed that the highest concentrations of ROS free radicals were generated when jute was incubated with laccase (0.54 U/mL) and copper ions (10 mM) in solution at pH 3.5 and a temperature of 60 °C for 1 h.     

阿奇霉素在多壁碳纳米管修饰电极上的电化学行为及其测定

运用循环伏安法与线性扫描伏安法研究了阿奇霉素在多壁碳纳米管修饰玻碳电极上的电化学行为,建立了一种直接测定阿奇霉素的电化学分析方法。结果表明,与裸玻碳电极相比,多壁碳纳米管修饰电极能显著提高阿奇霉素的氧化峰电流,阿奇霉素的电极过程完全不可逆,存在典型的吸附特性。在优化的实验条件下,氧化峰电流与阿奇霉素浓度在3.0×10-7～2.5×10-5 mol/L和2.5×10-5～5.0×10-4 mol/L范围内呈现良好的线性关系,检出限为1.0×10-7 mol/L。     

纵向数据半参数Beta回归模型的影响分析

本将随机效应当作是缺失数据,基于Q函数和EM算法并利用P-样条拟合非参数部分,得到了纵向数据半参数Beta回归模型估计方法.基于数据删除模型,我们得到了模型参数部分的广义Cook距离以及非参数部分的广义DFIT.此外,本文还研究了在四种不同扰动情形下模型的局部影响分析,得到了相应的影响矩阵.最后,我们通过两个数值实例验证了所得诊断统计量的有效性.     

含右删失数据的ZIP模型及其应用

零膨胀Poisson回归(ZIP)是处理零频数过多计数资料的有效模型,而计数数据一般含有删失或不精密的特点.本文将删失数据引入到ZIP模型中来,分别建立含右删失数据的固定效应ZIP模型,随机效应ZIP模型,通过极大边际似然函数估计法对模型进行参数估计.最后,利用实例分析验证了上述模型的可行性.     

Metal exchange kinetics: uncatalyzed replacement of Ni(II) from tetramethylenediaminetetraacetatonickel(II) complex by Cu(II)

The kinetics of metal exchange between copper(II) and tetramethylenediaminetetraacetatonickel(II), [Ni(TMDTA)] has been studied between pH 3.4 and 4.8 at an ionic strength of 1.25 M (NaClO₄) and a temperature of 25.0 ± 0.1 °C. The reaction is first order in [Ni(TMDTA)]. The reaction order in [Cu²⁺] varies from first to zero and then back to first as [Cu²⁺] is increased. At low copper concentration, the first-order rate constant is pH independent and represents the attack of copper on the nickel complex through a pathway in which TMDTA is partially uncoordinated before reaction with copper. Evidence is presented for a stepwise dechelation mechanism followed by attack of copper to give a dinuclear intermediate. The zero-order rate is pH dependent. At higher [Cu²⁺], the swing back to first order is due to the formation of a weak copper-tetramethylenediaminetetraacetatonickelate complex which then converts to products through a dinuclear intermediate. A plausible mechanism, consistent with all the kinetic data, is presented.