Electrochemical Behavior of Herbal Antitumor Drug Aloe‐Emodin at Carbon‐Coated Nickel Magnetic Nanoparticles Modified Glassy Carbon Electrode

The electrochemical behavior of aloe‐emodin (AE), an important herbal antitumor drug, was investigated at a carbon‐coated nickel magnetic nanoparticles modified glassy carbon electrode (CNN/GCE). A couple of well‐defined redox peaks was obtained. Some electrochemical parameters of AE at a CNN/GCE, such as the charge number, exchange current density, standard heterogeneous rate constant, were measured. The square wave voltammetry (SWV) response of AE was linear with the concentration over two concentration intervals viz. 6.24×10^?9?1.13×10^?6 M and 1.13×10^?6?1.23×10^?5 M, with a detection limit of 2.08 nM. A fast, simple and sensitive detection and analysis of AE was developed.     

Solvothermal synthesis of well-defined TiO(2) mesoporous nanotubes with enhanced photocatalytic activity

High efficiency TiO(2) photocatalyst in porous nanotubes were prepared by solvothermal alcoholysis of TiOSO(4) in the presence of carbon nanotube template.     

Development of fluorescent FeIII sensor based on chalcone

In this paper, 4-dimethylamino 2,5-dihydroxy chalcone (DMADHC), which exhibits excited state intramolecular charge transfer (ICT) characteristics, was synthesized and characterized. A sensitive optochemical sensor for Fe³⁺ ion was developed using DMADHC as fluorescence receptor. The fluorescence of DMADHC was gradually quenched with the addition of Fe³⁺ ion, which attributed to the formation of 1:1 complex between DMADHC and Fe³⁺ ion. The sensor exhibited excellent selectivity for Fe³⁺ ion over a large number of cation ions such as alkali, alkaline earth and transitional metal ions with a linear range of 3.984×10⁻⁷-1.135×10⁻⁵ and a limit of detection of 8.223×10⁻⁸ mol/L. On this basis, the sensor was preliminary applied to the determination of the content of iron ions in multi-vitamin tablet with satisfied results and the recoveries were in the 95-100% interval, and precision (n=5) was better than 5%.     

Visualizing electronic chirality and Berry phases in graphene systems using photoemission with circularly polarized light

Electronic chirality near the Dirac point is a key property of graphene systems, which is revealed by the spectral intensity patterns as measured by angle-resolved photoemission spectroscopy under various polarization conditions. Specifically, the strongly modulated circular patterns for monolayer (bilayer) graphene rotate by ±90° (±45°) in changing from linearly to circularly polarized light; these angles are directly related to the phases of the wave functions and thus visually confirm the Berry's phase of π (2π) around the Dirac point. The details are verified by calculations.     

纳秒脉冲下聚合物电树枝引发实验方法

 借鉴直流、交流的研究经验,比较了纳秒脉冲条件下几种不同的电树枝老化实验方法。对单针-板电极和多针-板电极在纳秒脉冲下实验结果的一致性进行考察,结果表明,多针-板电极系统可以在提高实验效率的同时保证结果的准确性。采用步进法和累加法进行了不同频率下聚苯乙烯电树枝引发实验,结果表明:两种方法得到的纳秒脉冲下聚苯乙烯电树枝引发电压-频率特性基本一致,在50~500 Hz范围内,引发电压随频率的升高而降低;在500~800 Hz范围内,引发电压随频率的升高而增加。最后讨论了对于不同脉冲功率装置中绝缘材料老化试验设计的方法。     

Combining clustering and classification for remote-sensing images using unlabeled data

A joint clustering and classification approach is proposed.This approach exploits unlabeled data for efficient clustering,which is applied in the classification with support vector machine(SVM) in the case of small-size training samples.The proposed method requires no prior information on data labels,and yields better cluster structures.Through cluster assumption and the notions of support vectors,the most confident k cluster centers and data points near the cluster boundaries are labeled and used to train a reliable SVM classifier.Our method gains better estimation of data distributions and mitigates the unrepresentative problem of small-size training samples.The data set collected from Landsat Thematic Mapper(Landsat TM-5) validates the effectiveness of the proposed approach.     

X射线荧光光谱研究粮食中生命有机碳与碳化学循环

采用X射线荧光光谱(XRF)方法测定六种粮食:稻谷(大米)、小麦(面粉)、黄豆、小米、高粱和玉米中生命有机碳含量和化学元素组成,建立一种新方法测定它们的蛋白质含量.粮食中生命有机碳平均含量约为44%.黄豆中的蛋白质含量最高(42.74%),小米蛋白质含量28.56%,麦子蛋白质含量27.57%,玉米蛋白质含量24.99...     

SEM-EDXA分析不同生长应力木材细胞壁微区木质素沉积

选取具不同生长应力水平的人工林尾巨桉(Eucalyptus uroph ylla×E.grandis)正常木为研究对象,借助场发射环境扫描电子显微镜系统,结合以溴元素做标记的X射线能谱分析技术,分析了尾巨桉细胞壁微区木质素沉积与生长应力的关系.研究结果表明,木纤维细胞壁各微区间木质素含量的大小关系与生长应力高低无关,其...     

Schur Convexity for Two Classes of Symmetric Functions and Their Applications

For x =(x1, x2, ···, xn) ∈ Rn+∪ Rn-, the symmetric functions Fn(x, r) and Gn(x, r) are defined by r1 + xFij n(x, r) = Fn(x1, x2, ···, xn; r) =x1≤iij1i2···ir ≤n j=1and r1- xGij n(x, r) = Gn(x1, x2, ···, xn; r) =,x1≤i1i2···ir ≤n j=1ij respectively, where r = 1, 2, ···, n, and i1, i2, ···, in are positive integers. In this paper,the Schur convexity of Fn(x, r) and Gn(x, r) are discussed. As applications, by a bijective transformation of independent variable for a Schur convex function, the authors obtain Schur convexity for some other symmetric functions, which subsumes the main results in recent literature; and by use of the theory of majorization establish some inequalities. In particular, the authors derive from the results of this paper the Weierstrass inequalities and the Ky Fan's inequality, and give a generalization of Safta's conjecture in the n-dimensional space and others.     

Global Existence and Asymptotic Behavior for the 3D Compressible Non–isentropic Euler Equations with Damping

We investigate the global existence and asymptotic behavior of classical solutions for the 3D compressible non-isentropic damped Euler equations on a periodic domain. The global existence and uniqueness of classical solutions are obtained when the initial data is near an equilibrium. Furthermore, the exponential convergence rates of the pressure and velocity are also proved by delicate energy methods.