Lu2Si2O7∶Ce纳米晶的溶胶-凝胶法合成和闪烁性能

采用溶胶-凝胶法制备了Lu2Si2O7∶Ce纳米晶,利用X射线衍射(XRD)、扫描电镜(SEM)、荧光光谱仪、X射线激发发射谱仪对制备的Lu2Si2O7∶Ce纳米晶的晶相结构、微观形貌和光学性能进行了表征。结果表明,溶胶-凝胶法制备的Lu2Si2O7∶Ce前驱体在煅烧温度为1000℃时开始晶化,晶粒尺寸随着煅烧温度的升高而变大,1200℃煅烧2 h后的晶体颗粒均匀,分散性最优,平均晶粒尺寸约为28.9 nm,呈近球形;Lu2Si2O7∶Ce纳米晶的紫外吸收谱存在峰位分别为304 nm和350 nm两个吸收峰,源自于Ce^3+离子的4f→5d跃迁;光致发射谱和X射线激发发射谱都表现为典型的非对称双峰结构,归属于Ce^3+离子的5d^1→2F5/2和5d^1→2F7/2跃迁,Ce^3+离子的最佳掺杂浓度约为1%;荧光衰减时间约为37.2 ns,可满足高时间分辨X射线探测需要。     

基于Pt/Au双金属修饰针灸针的非酶葡萄糖传感器

通过在不锈钢针灸针（AN）表面依次电沉积金（Au）纳米颗粒和铂（Pt）纳米颗粒,基于它们在AN表面的协同作用,实现了一种用于非酶葡萄糖检测的电化学生物传感器。首先,通过扫描电子显微镜对其功能界面（Pt/Au/AN）进行表征,结果显示类似卷心菜的纳米材料均匀致密地分布在AN表面。然后,通过循环伏安法和电化学阻抗法对Pt/Au/AN电极的电化学特性进行了研究。结果表明,与Au/AN或Pt/AN电极相比,Pt/Au/AN电极对葡萄糖氧化表现出优越的电催化活性。这表明双金属Pt/Au的接触界面是葡萄糖氧化的重要电催化位点。在pH7.4的模拟生理介质中,制得传感器的线性范围为0.1~35 mmol·L^-1,检测限为0.0763 mmol·L^-1,对葡萄糖的检测表现出较高的灵敏度和良好的抗干扰性能、稳定性。此外,该传感器已成功用于人体血清葡萄糖的检测。     

基于不同碱基含量的[FeFe]-氢化酶模型化合物功能化聚合物的合成与表征

将含二炔基的[2Fe2S]模型化合物[Fe2(μ-SCH2C≡CH)2(CO)6](A)和双叠氮单体2,6-(N3CH2)Py(B,Py=吡啶)与含碱性基团的双炔单体(2-Py CH2)N(CH2C≡CH)2(C,Py=吡啶)通过"点击反应"以不同比例进行共聚,得到了6种含不同碱基量的[FeFe]-氢化酶模型化合物功能聚合物Polymer-1~Polymer-6。通过红外光谱、硫元素分析、热重、扫描电镜和电化学对这些聚合物进行了表征。红外光谱和电化学研究表明二铁六羰基单元A以二铁五羰基的形式存在于聚合物中。在共聚过程中,增加单体C的含量能显著改变聚合物的形貌和增加其在有机溶剂中的溶解度,同时热稳定性也有所增加。这些聚合物在含有醋酸的DMF介质中催化质子还原的行为表明,通过单体C引入的碱性基团所形成的次级配位环境对二铁中心的催化性能有显著影响。     

一类一阶中立型泛函微分方程周期解的存在与唯一性

利用重合度理论研究并获得了如下一类一阶中立型泛函微分方程T-周期解的存在与唯一性(x(t)+Bx(t-δ))′：g1(t,x(t))+g2(t,x(t-τ(t)))+p(t)．     

THE ASYMPTOTIC DISTRIBUTIONS OF EMPIRICAL LIKELIHOOD RATIO STATISTICS IN THE PRESENCE OF MEASUREMENT ERROR

Suppose that several different imperfect instruments and one perfect instrument are independently used to measure some characteristics of a population. Thus, measurements of two or more sets of samples with varying accuracies are obtained. Statistical inference should be based on the pooled samples. In this article, the authors also assumes that all the imperfect instruments are unbiased. They consider the problem of combining this information to make statistical tests for parameters more relevant. They define the empirical likelihood ratio functions and obtain their asymptotic distributions in the presence of measurement error.     

An anti-periodic LaSalle oscillation theorem for a class of functional differential equations

In this paper, we establish a result on the existence of anti-periodic solution for a class of functional differential equations, which substantially extends and improves some important results in the literature.     

Almost periodic solutions for shunting inhibitory cellular neural networks with time-varying delays

In this paper the shunting inhibitory cellular neural networks (SICNNs) with time-varying delays are considered. Without assuming the global Lipschitz and bounded conditions of activation functions, sufficient conditions for the existence of the almost periodic solutions are established by using a fixed point theorem. The results of this paper are new and complement previously known results.     

Synchronization stability of general complex dynamical networks with time-varying delays: A piecewise analysis method

The synchronization problem of some general complex dynamical networks with time-varying delays is investigated. Both time-varying delays in the network couplings and time-varying delays in the dynamical nodes are considered. The delays considered in this paper are assumed to vary in an interval, where the lower and upper bounds are known. Based on a piecewise analysis method, the variation interval of the time delay is firstly divided into several subintervals, by checking the variation of the derivative of a Lyapunov function in every subinterval, then the convexity of matrix function method and the free weighting matrix method are fully used in this paper. Some new delay-dependent synchronization stability criteria are derived in the form of linear matrix inequalities. Two numerical examples show that our method can lead to much less conservative results than those in the existing references.     

密立根油滴实验中影响油滴控制的因素分析及对策

本文分析了密里根油滴实验中影响油滴控制的主要因素,并提出了相应的对策。