Hydrothermal synthesis of FeS2 for lithium batteries

Nanocrystalline FeS₂ cathode material of lithium cell was synthesized from cheap materials of FeSO₄, Na₂S₂O₃, and sulfur by a hydrothermal process. The scanning electron microscopy analysis showed the obtained material was nano-sized, about 500 nm. The X-ray powder diffraction analysis showed that the synthetic FeS₂ material had two phases of the crystalline structure, pyrite and marcasite. The phase of marcasite seems to have no negative effect on the electrochemical performance of the material. The synthetic FeS₂ showed a significant improvement of electrochemical performance for Li/FeS₂ cells.     

Preparation of antimicrobial poly(vinyl alcohol) nanofibers containing silver nanoparticles

Polyvinyl alcohol (PVA) nanofibers containing Ag nanoparticles were prepared by electrospinning PVA/silver nitrate (AgNO₃) aqueous solutions, followed by short heat treatment, and their antimicrobial activity was investigated for wound dressing applications. Since PVA is a water soluble and biocompatible polymer, it is one of the best materials for the preparation of wound dressing nanofibers. After heat treatment at 155 °C for 3 min, the PVA/AgNO₃ nanofibers became insoluble, while the Ag⁺ ions therein were reduced so as to produce a large number of Ag nanoparticles situated preferentially on their surface. The residual Ag⁺ ions were reduced by subsequent UV irradiation for 3 h. The average diameter of the Ag nanoparticles after the heat treatment was 5.9 nm and this value increased slightly to 6.3 nm after UV irradiation. It was found that most of the Ag⁺ ions were reduced by the simple heat treatment. The PVA nanofibers containing Ag nanoparticles showed very strong antimicrobial activity. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2468–2474, 2006     

T-C模型中虚光子过程对光场压缩效应的影响

利用全量子理论,研究非旋波近似下TC模型中受激场的压缩效应.结果表明:非旋波近似下,由于虚光场的影响,Q的演化曲线出现了“小锯齿状”,表现为系统的量子噪声,随着ω和n的增大,量子噪声分别减小和增大,虚光子过程使光场的压缩程度明显加深;研究结果还揭示了原子场耦合系数λ及原子间耦合系数g与光场压缩效应的关系. 关键词： T-C模型 非旋波近似 压缩效应 量子噪声     

聚异丁烯高活性端基含量及相对分子质量测定方法的研究

综合使用核磁，VPO和近红外光谱分析技术对聚异丁烯活性端基含量以及相对分子质量的测定进行了详细研究，分别建立核测定聚异丁烯活性端基含量以及其他烯键含量和近红外光谱快速测量聚异聚丁烯活性端基含量。其他烯键含量和相对分子质量的分析方法。成对t检验结果表明，近红外光谱分析方法测定结果与核磁和VPO方法测定结果之间无显著性差异。     

Interaction of metals with an organic semiconductor: Ag and In on PTCDA

The interaction of Ag and In with a thin film of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) was studied by near-edge X-ray absorption fine structure (NEXAFS). Upon Ag deposition on a PTCDA film of 20 nm thickness the relative intensities and lineshapes, as well as the angular dependence of the spectra remains unchanged, illustrating the formation of a chemically unreactive Ag/PTCDA interface. On the other hand, the adsorption of 0.3 nm In strongly decreases the intensity of the π^* resonances in C and O K-edge NEXAFS spectra. This is attributed to a strong charge transfer between In and PTCDA, leading to a redistribution of the charge in the molecule. However, the absence of a strong shift or new features and negligible dependence of peak intensities corresponding to π^* resonances on the In thickness indicate that the interaction between In and PTCDA is not accompanied by a covalent bond formation.     

0.18μm CMOS工艺栅极氧化膜可靠性的衬底和工艺依存性

用斜坡电压法(Voltage Ramp, V-ramp)评价了0.18μm双栅极 CMOS工艺栅极氧化膜击穿电量(Charge to Breakdown, Q_bd)和击穿电压(Voltage to Breakdown, V_bd). 研究结果表明，低压器件(1.8V)的栅极氧化膜(薄氧)p型衬底MOS电容和N型衬底电容的击穿电量值相差较小，而高压器件(3.3V)栅极氧化膜(厚氧)p衬底MOS电容和n衬底MOS电容的击穿电量值相差较大，击穿电压测试值也发现与击穿电量 关键词： 薄氧 可靠性 击穿电压 击穿电量     

Synchronization of a class of chaotic dynamic systems with controller gain variations

In this paper, the nonfragile control problem for synchronization of a class of chaotic dynamical systems with controller gain variations is studied. Using the Lyapunov method and LMI (linear matrix inequality) technique, a criterion for the existence of the nonfragile controller for synchronization is derived in terms of LMI. To show the effectiveness of the proposed method, the control problem is applied to Genesio chaotic system.     

High-pressure effect on the crystal and magnetic structure of LuMnO3: Correlation between a distortion of the triangular lattice and the symmetry of the magnetic state in hexagonal frustrated manganites

The effect of a high pressure (up to 6 GPa) on the crystal and magnetic structure of the hexagonal manganite LuMnO₃ is studied by neutron diffraction in the temperature range 10–295 K. It is found that, as the pressure increases, the ordered magnetic moment of Mn ions at T = 10 K decreases noticeably from 2.48 (0 GPa) to 1.98 μ_B (6 GPa). This decrease is due to an enhancement of the geometrical frustration effects on the triangular lattice. At the same time, the symmetry of the triangular antiferromagnetic state (the irreducible representation Γ₂) remains unchanged. A correlation is revealed between the distortion parameter of the triangular lattice formed by Mn ions and the symmetry of the antiferromagnetic state of hexagonal manganites RMnO₃. Based on this correlation, a generalized magnetic phase diagram of these compounds is constructed. The obtained phase diagram provides an explanation for the changes observed in the magnetic state of hexagonal manganites caused by high pressure and chemical substitution.     

泛函梯度数值计算的一种新方法—正交试验法

本文研究并揭示了L_(2~a)(2~(2~a-1))型正交表行(列)间的递推规律,提出了一种泛函梯度数值计算的新方法——正交试验法,该方法在计算速度和精度上优于直接梯度法;在通用性及节省内存方面优于伴随算子法。     

Microwve inducdd catalytic decomposition of some alberta oil sands and bitumens

The processing of oil sands materials and upgrading of bitumens present a variety of problems for conventional technologies. This article describes a preliminary study of the concept of using microwave induced catalytic techniques to decompose the complex and viscous hydrocarbon compounds contained in these materials to allow efficient extraction of volatile and economically useful organic products such as C₂ and C₃ hydrocarbons. Addition of water to the tar sand material prior to reaction facilitated separation from the sand component as well as promoting the formation of economically very useful, liquid, oxygenated hydrocarbon products.