Phase stability of Crn+ 1GaCn MAX phases from first principles and Cr2GaC thin‐film synthesis using magnetron sputtering from elemental targets

Ab‐initio calculations have been used to investigate the phase stability and magnetic state of Cr_{n+ 1}GaC_n MAX phase. Cr₂GaC (n = 1) was predicted to be stable, with a ground state corresponding to an antiferromagnetic spin configuration. Thin‐film synthesis by magnetron sputtering from elemental targets, including liquid Ga, shows the formation of Cr₂GaC, previously only attained from bulk synthesis methods. The films were deposited at 650 °C on MgO(111) substrates. X‐ray diffraction and high‐resolution transmission electron microscopy show epitaxial growth of (000?) MAX phase. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

从野生与突变株云芝IBL-04提纯锰过氧化物酶及其表征

由野生及突变株云芝IBL-04制得细胞外锰过氧化物酶(MnPs)，并经过硫酸铵沉淀、透析、离子交换和凝胶渗透层析法等步骤提纯.纯化的酶在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)上于43 kDa区域呈现单一谱带，它适宜的pH值和温度分别为5.0和40°C.突变株MnPs表现出比野生株MnPs更宽的活性pH值范围和更高的热稳定性.从所选突变株所得纯化的MnPs表现出与野生株MnP几乎相同的电泳性质、稳态动力学、金属离子和EDCs降解效率.该生物酶与Mn2+一起催化的反应速率最快，但最高的亲和性对应于ABTS、甲氧基羟苯基乙二醇、4-氨基苯酚和活性染料. Mn2+和Cu2+可显著提高MnPs的活性，但Zn2+， Fe2+， EDTA和半胱氨酸则会不同程度地抑制其活性， Hg2+是最强的活性抑制剂.所有来源的MnPs均可有效催化EDCs、壬基苯酚和二氯苯氧氯酚降解，处理3 h可除去80%以上，在MnPs-介质体系中可进一步提高到90%.综上，云芝MnPs生物酶具有较高的pH适用性和热稳定性、独特的Michaelis-Menten动力学参数和高的EDCs去除效率等特点，因而有望工业化应用.     

Electrical and Sensing Properties of Single‐Walled Carbon Nanotubes Network: Effect of Alignment and Selective Breakdown

The electrical transport and NH₃ sensing properties of randomly oriented and aligned SWNT networks were presented and discussed. The results indicate that aligned SWNT‐FETs have better FET characteristics due to the reduced number of interconnected nodes. This was particularly true as the resistance of the devices increased. Gated electrical breakdown was implemented to selectively remove metallic (m‐) SWNTs, thereby reducing scattering centers. This technique provided significant improvements in FET characteristics resulting in greater on/off ratio (e.g. 10⁴). AC dielectrophoretic alignment followed by selective electrical breakdown of m‐SWNTs can significantly enhance the semiconducting properties of SWNT networks which resulted in highly sensitive sensors.     

Thermochromism and Solvatochromism in Solution

 The thermochromic behaviour of various coordination compounds in solution is discussed, with a special focus on cyclic diamine chelates. Thermally induced spin-crossover phenomena of iron(II) complexes are also considered. The solvatochromic behaviour of mixed-ligand complexes is presented in detail.     

On the optimization properties of the correntropic loss function in data analysis

Similarity measures play a critical role in the solution quality of data analysis methods. Outliers or noise often taint the solution, hence, practical data analysis calls for robust measures. The correntropic loss function is a smooth and robust measure. In this paper, we present the properties of the correntropic loss function that can be utilized in optimization based data analysis methods.     

An efficient method for the construction of block cipher with multi-chaotic systems

In this article, we present a method to synthesize strong nonlinear components used in encryption algorithms. The proposed nonlinear component assists in transforming the intelligible message or plaintext into an enciphered format by the use of Lorenz and Rössler chaotic systems. A substitution box is generated that uses initial conditions, utilize multi-chaotic parameter values, and employ numerical simulations.     

Fabrication and characterization of amidoxime-functionalized silica decorated with copper: a catalytic assembly for rapid reduction of dyes

In this study, amidoxime-functionalized silica decorated with copper (AFS-Cu) was fabricated and tested for its catalytic application. Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction were employed to characterize its structure and morphology. The application of AFS-Cu as a catalyst for the catalytic reduction of methylene blue (MB) in aqueous media using NaBH₄ as reductant was evaluated. The ability to reuse as well as the effect of catalyst dose and pH of solution on the catalytic activity was investigated. The reduction of MB followed pseudo-first-order kinetics and the rate constant (k) was 0.6224 min^-1. AFS-Cu was found to be a highly effective catalyst for MB reduction reaction and can be easily recovered and reused several times with no appreciable loss of catalytic activity.     

α‐Hydroxymethylation of Pyridines at a Frustrated Lewis Pair Template

The “η²‐formylborane” moiety formed by CO reduction with HB(C₆F₅)₂ at a P/B frustrated Lewis pair template undergoes a hydroxymethylation reaction at the α‐position to nitrogen in pyridine or isoquinoline. The analogous reaction with pyrimidine revealed a mechanism related to the Tschitschibabin reaction.