The Armstrong-Frederick Plasticity model with Cosserat effects

We propose an extension of equations formulated by Armstrong and Frederick which includes micropolar effects. We study existence of solutions to the quasistatic Armstrong-Frederick model with Cosserat effects which is still of non-monotone type. It was shown that the limit in the Yosida approximation process satisfies the energy inequality. The limit functions have a better regularity than it could be found in the literature, where the original Armstrong-Frederick model was studied. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

A low complexity block-based adaptive lossless image compression

For low power and lossless image compression, in this paper, a low complexity, block-based decomposition of subbands technology is proposed for embedded compression (EC) algorithm, which is ready for being implemented on a single-chip of FPGA. The proposed algorithm is based on high-speed pipeline architecture of 2-D lossless integer wavelet transformation (IWT) with 2-D Lossless Hadamard Transformation (LHT). In the proposed algorithm, the coefficients of a 2-D IWT are decomposed by 4 × 4 blocks to further remove redundancy, compared with direct encoder by EBCOT of JPEG2000. Considering the feature of the 2-D IWT, a different strategy is designed for LL-subband and non-LL subbands, which denotes DC prediction (DCP) and adaptive transformation method (ATM), respectively. DCP is used to remove the correlation between two adjacent blocks of LL-subband, and ATM is used to transform non-LL subbands by 2-D LHT selectivity. After further transformation, the coefficients are decomposed as truncated integer part (TIP) and truncated residue parts (TRP), considering the complexity of hardware implementation, TIP is encoded by Zero Running Length (ZRL) and Exp-Golomb (EG). TRP is encoded by a fixed length (FL) encoder after removed redundancy by the feature of 2-D LHT, when seen as bit patterns [1]. Experimental results show that the proposed EC algorithm can achieve a good compression performance as JPEG2000, and the coding latency can be decreased at an average of 43.9%. Another innovation of this paper is EC's hardware-friendly feature and easy hardware implementation, which are presented by a simple addition or subtraction of the LIWT and LHT, and need a small on-chip memory.     

Effects of Ionic Liquids on Fluorescence Characteristics of 17α- and 17β-estradiol

Herein, we report the effects of six different room temperature ionic liquids (RTILs) on fluorescence spectra of 17α-estradiol (EE1) and 17β-estradiol (E2). The selected RTILs belonged to the compound classes of 1-alkyl-3-methylimidazolium tetrafluoroborate ([C_nMIM]BF₄) and 1-alkyl-3-methyl imidazolium hexafluorophosphate ([C_nMIM]PF₆). RTILs had a gradual quenching effect on fluorescence intensity (FI) of EE1 and E2, and the quenching process followed the well-known Stern-Volmer theory. The quenching mechanism of EE1 and E2 by RTILs was demonstrated to be dynamic quenching. Additionally, the overall quenching efficiency by [C_nMIM]BF₄ was higher than [C_nMIM]PF₆. The increased carbon chain length of RTILs did not lead to obvious differences in FI for EE1 and E2. The quenching efficiency showed irregular trend at three different temperatures (25, 35 and 45 °C). RTILs such as [C₄MIM]PF₆ had the different fluorescent effects on organic chemicals with different fluorophores. The enhancing effects of [C₄MIM]PF₆ were observed on strong fluorescence chemicals (dansyl chloride, rhrodamine B, 1,10-phenanthroline, norfloxacin), while quenching effect on weak fluorescence chemicals (EE1 and E2). In theory, these results provide a theoretical foundation for deep insight into their interaction mechanism between RTILs and estradiol.     

Aggregation Behavior of Copolymer Containing Sulfobetaine Structure in Aqueous Solution

Copolymers containing sulfobetaine (P(AM/DMAPS)) were synthesized by aqueous copolymerization of acrylamide with 3-[N-(2-methacroyloylethyl)-N,N- dimethylammonio]-propane sulfonate. Aggregation and disaggregation of P(AM/ DMAPS) copolymer in aqueous solution as a function of copolymer concentration, added salts, and temperature were studied by dynamic laser light scattering. P(AM/DMAPS) copolymers exist as a mixture of individual chains and interchain aggregation in deionized water. At low copolymer concentrations (below 1.0 g L^?1), the intrachain aggregation is dominant. With increasing copolymer concentration, the interchain aggregation is enhanced. The addition of a small amount of salts (C_NaCl < 0.1 mol L^?1; C_MgCl2/CaCl2 < 0.05 mol L^?1) leads to the disaggregation of the intra- and interchain aggregation. Further addition of salts results in the enhancement of interchain aggregation. The influence of various cations (Na⁺, Ca²⁺, Mg²⁺) on the aggregation behavior increases in the order Na⁺ < Ca²⁺ < Mg²⁺. The increase of temperature from 25°C to 60°C facilitates the breakup of intrachain aggregation and the enhancement of interchain aggregation.     

不同压力下介质阻挡放电等离子体诱导流场演化的实验研究

采用粒子图像测速技术, 获得了不同环境压力下介质阻挡放电等离子体诱导流场启动涡随时间的演化规律和诱导流场分布的变化规律. 实验表明: 不同环境压力下, 诱导流场都会出现启动涡, 压力较高, 启动涡逐渐向右即向植入电极一侧扩散并最终消失, 扩散速度随时间递减, 压力较小, 诱导漩涡不会随放电时间的增大而消失; 环境压力减小, 等离子体诱导流场的启动时间减小, 诱导流场的法向分量增强、横向分量减弱, 诱导流线形状的变化规律是:L→U→V, L 型流线没有诱导漩涡, U 型流线有两个诱导旋涡, 分别分布在U 型凹槽和右侧, V 型流线有一个诱导漩涡, 分布在V 中间. 关键词： 介质阻挡放电 诱导流场 启动涡 演化     

超高压下碘的结构相变

 采用DAC高压X光技术，在320 GPa压力下，对碘进行了结构相变的研究。用耐腐蚀材料Mo作封垫，在室温和无保护气氛下装样。采用Mo内标和红宝石荧光测量进行压力校准。结果表明，在21 GPa时，开始发生结构相变，由面心正交相（Ⅰ相），转变为体心正交相（Ⅱ相），体积缩小2%左右。在21~25 GPa之间为两相共存区；在25 GPa以上完全转变为新的高压单相（Ⅱ相）。此相变为可逆相变。     

Reaction Dynamics with Molecular Beams and Oriented Molecular Beams: A Tool for Looking Closer to Chemical Reactions and Photodissociations

Experimental studies on reaction dynamics by use of molecular beams and oriented molecular beams are reviewed in order for looking closer to chemical reactions as well as photodissociations at the molecular level. We discuss about versatility and usefulness of the electrostatic hexapole sate‐selector as a non‐destructive selector for molecular structure analysis. Some experimental evidences on novel reaction dynamics in photodissociation and stereodynamics are presented followed by concluding remarks and future perspectives for controlling chemical reactions from the point of view of green chemistry, by manipulating molecular orientation without any catalyst nor by applying any external forces like intense electromagnetic field.     

Two acentric mononuclear molecular complexes with unusual magnetic and ferroelectric properties

Two acentric, i.e., noncentrosymmetric, mononuclear complexes, Co(5-ATZ)(4)Cl(2), 1, and Cu(5-ATZ)(4)Cl(2), 2, where 5-ATZ is the monodentate 5-amino-1-H-tetrazole ligand, have been prepared and characterized. Both complexes crystallize in the tetragonal system with the P4nc space group, a member of the polar noncentrosymmetric 4mm class, and thus both 1 and 2 can exhibit ferroelectric and nonlinear optical properties. Magnetic studies indicate that 1 is a paramagnetic high-spin cobalt(II) complex with a rather extensive spin-orbit coupling, modeled as a zero-field splitting parameter, D, of ±91(3) cm(-1) and with very weak long-range antiferromagnetic exchange interactions. Direct current (dc) and ac magnetic studies indicate that 2 is a paramagnetic copper(II) complex that exhibits weak ferromagnetic exchange interactions below 15 K. Both 1 and 2 exhibit ferroelectric hysteresis loops at room temperature with remanent polarizations of 0.015 μC/cm(2) and coercive electric fields of 5.5 and 5.7 kV/cm, respectively.     

6-Hydroxyindole-based borondipyrromethene: synthesis and spectroscopic studies

A 6-hydroxyindole-based BODIPY, named BODIPY-OH, with distinct spectroscopic characteristics is reported. Through a systematic study of the spectroscopic characteristics of BODIPY-OH and BODIPY-O(-) in various solvents containing an organic base, we found that the light-color of the fluorophore can be tuned over a wide range by changing the polarity of solvent/base combinations. The absorption color of the solution can be tuned over a range of 100 nm and the emission color within a wide range from 571 to 681 nm by simply converting the phenol form of BODIPY-OH to the phenolate form. Fluorescence of BODIPY-O(-) with high quantum yield shows relatively large Stokes shift in solvent/base combinations, which are ascribed to the excited state deprotonation from (BODIPY-OH)* to (BODIPY-O(-))*, followed by emission from the ion form.