Synthesis of cubic mesoporous silica and carbon using fly ash

A supernatant solution of silicate species extracted from coal fly ash in a power plant by alkali fusion was used under acidic conditions to prepare a mesoporous silica, SBA-16. SBA-16 was used as a template for the synthesis of a mesoporous carbon using sucrose as a carbon source. These mesoporous silica and carbon materials were characterized by XRD, N₂ adsorption-desorption, SEM, and TEM. Textural properties of the silica and carbon samples prepared using fly ash were found to be comparable to those prepared by pure chemicals, successfully demonstrating the feasibility of recycling fly ash for the synthesis of high quality porous materials.     

2-Amino-6-methylpyridinium nitrophenolate nitrophenol

Journal of Thermal Analysis and Calorimetry - Organic co-crystals fashioned with two or more different constituents through intermolecular non-covalent interactions (hydrogen and halogen bonds)...     

Boron-Thioketonates: A New Class of S,O-Chelated Boranes as Acceptors in Optoelectronic Devices

Development of new n-type semiconductors with tunable band gap and dielectric constant has significant implication in dissociating bound charge carrier relevant for demonstrating high performance optoelectronic devices. Boron-β-thioketonates (MTDKB), analogues to boron-β-diketonates containing a sulfur atom in the framework of β-diketones were synthesized. Bulk transport measurement exhibited an outstanding bulk electron mobility of ≈0.003 cm² V⁻¹ s⁻¹, which is among the best values reported till date in these class of semiconducting materials and correspondingly a single junction photo responsivity of upto 6 mA W⁻¹ was obtained. This new family of O,S-chelated boron compounds exhibited luminescence in the far red/near-infrared region. The remarkable red shift of 89 nm (fluorescence) observed for 4 a in comparison with analogues boron-β-diketonate signifies the importance of sulfur in these molecules. MTDKBs with amine functionality have also been investigated as an ON/OFF fluorescent sensor.     

Robust stability analysis of stochastic neural networks with Markovian jumping parameters and probabilistic time‐varying delays

This article discusses the issue of robust stability analysis for a class of Markovian jumping stochastic neural networks (NNs) with probabilistic time‐varying delays. The jumping parameters are represented as a continuous‐time discrete‐state Markov chain. Using the stochastic stability theory, properties of Brownian motion, the information of probabilistic time‐varying delay, the generalized Ito's formula, and linear matrix inequality (LMI) technique, some novel sufficient conditions are obtained to guarantee the stochastical stability of the given NNs. In particular, the activation functions considered in this article are reasonably general in view of the fact that they may depend on Markovian jump parameters and they are more general than those usual Lipschitz conditions. The main features of this article are described in the following: first one is that, based on generalized Finsler lemma, some improved delay‐dependent stability criteria are established and the second one is that the nonlinear stochastic perturbation acting on the system satisfies a class of Lipschitz linear growth conditions. By resorting to the Lyapunov–Krasovskii stability theory and the stochastic analysis tools, sufficient stability conditions are established using an efficient LMI approach. Finally, two numerical examples and its simulations are given to demonstrate the usefulness and effectiveness of the proposed results. © 2014 Wiley Periodicals, Inc. Complexity 21: 59–72, 2016     

Self‐Assembly of “Chalcone” Type Push‐Pull Dye Molecules into Organic Single Crystalline Microribbons and Rigid Microrods for Vis/NIR Range Photonic Cavity Applications

A novel supramolecular fluorescent donor–acceptor type dye molecule, (2E,4E)‐1‐(2‐hydroxyphenyl)‐5‐(pyren‐1‐yl)penta‐2,4‐dien‐1‐one (HPPD) self‐assembles in a mixture of ethanol/chloroform through intermolecular π–π stacking (distance ca. 3.384 Å) to form J‐aggregated single‐crystalline microribbons displaying Fabry–Pèrot (F‐P) type visible‐range optical resonance. The corresponding borondifluoride dye (HPPD‐BF), with a reduced HOMO–LUMO gap, self‐assembles into crystalline microrods acting as an F‐P type resonator in the near‐infrared (NIR) range.     

A dexterous feature selection artificial immune system algorithm for keystroke dynamics

The main problem in security protecting the computer or resources from intruders. The password and username are the most common means to provide security. But this method has many loop holes such as password sharing, shoulder surfing, brute-force attack, dictionary attack, guessing, and many more. Keystroke dynamics is one popular and inexpensive behavioral biometric technology, which identifies the authenticity of a user when the user is working via a keyboard. Keystroke features like dwell time and flight time of every user are evaluated in this paper by preprocessing techniques such as Hausdroff timing, mean, median, and standard deviation. The artificial immune system is used for feature selection, and comparison between preprocessing techniques is shown.     

Magnetic interactions in supramolecular N-O...H-C[triple bond]C- type hydrogen-bonded nitronylnitroxide radical chains

Two paramagnetic building blocks, 2-(4-ethynyl-1-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl (3) and 2-(5-ethynyl-2-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl (4) were synthesized and crystallized. Single crystal X-ray studies of 3 and 4 show the formation of supramolecular head-to-tail one-dimensional H-bonded (N-O...H-C[triple bond]C- type) chain structures with O...C distances of 3.181 and 3.155 A, respectively. High-resolution isotropic liquid state (c相似文献