Tunable graphene-based mid-infrared band-pass planar filter and its application

We have designed and proposed the edge modes supported by graphene ribbons and the planar band-pass filter consisting of graphene ribbons coupled to a graphene ring resonator by using the finite-difference time-domain numerical method.Simulation results show that the edge modes improve the electromagnetic coupling between devices. This structure works as a novel, tunable mid-infrared band-pass filter. Our studies will benefit the fabrication of planar, ultra-compact nano-scale devices in the mid-infrared region. A power splitter consisting of two output ribbons that is useful in photonic integrated devices and circuits is also designed and simulated. These devices are useful for designing ultra-compact planar devices in photonic integrated circuits.     

Green synthesis of bis-coumarin derivatives using Fe(SD)3 as a catalyst and investigation of their biological activities

A convenient, practical, green, and environmentally friendly method was developed for the synthesis of biscoumarins and corresponding tetrakis products from the reaction of 4-hydroxycoumarin and various aldehydes. The bis-coumarins were synthesized in high yield under mild reaction conditions. Products were obtained in the presence of in situ prepared Fe(SD)₃ [Iron(III) dodecyl sulfate] as a combined Lewis acid–surfactant catalyst (LASC) in water in short reaction times. Also, the antibacterial activity of compounds was screened against Pseudomonas aeruginosa and Escherichia coli as Gram-negative bacteria and Micrococcus luteus and Staphylococcus aureus as Gram-positive bacterial strains. Products 3g , 3k–l were most active than cefotaxime against E. coli and also compounds 3c and 3g were most active than cefotaxime against S. aureus.     

Synthesis and antibacterial evaluation of diaminomaleonitrile-based azo-Schiff bases and 8,9-dihydro-7H-purine-6-carboxamides

Research on Chemical Intermediates - Some new DAMN-based Schiff base 6a–6g were synthesized via a condensation reaction of the corresponding azo dyes with...     

Complete analysis of photonic crystal fibers by full-vectorial 2D-FDTD method

In this paper, an extended finite difference time domain (FDTD) algorithm for the full-vectorial analysis of photonic crystal fibers has been derived. For achieving a good convergence and high accuracy, a kind of modified conformal FDTD method has been applied. An anisotropic perfectly matched layer for truncation of boundary conditions has been introduced. Material and chromatic dispersions are numerically investigated for the photonic crystal fibers with different dimensions and geometrical parameters and different dispersion behaviors are exhibited.     

A convenient synthesis of 1,5-diarylpyrazoles from Baylis-Hillman adducts using HY-zeolite

<正>A facile and convenient protocol was developed for the synthesis of 1,5-diarylpyrazoles using Baylis-Hillman adducts in the presence of HY-zeolite as an efficient recyclable heterogeneous catalyst in reasonable reaction times(1.5-2.5 h) and high yields (78-90%).     

Analysis and design of a dye-doped polymer optical fiber amplifier

A rhodamine-B-doped polymer optical fiber amplifier (RBDPOFA) has been successfully fabricated and tested. In this paper, all parameters affecting the gain of the RBDPOFA are recognized. The time-dependent and time-independent rate equations are solved. By using Runge–Kutta and finite-element methods, different conditions are described and fluctuations of the fiber laser are analyzed. From the time-dependent rate equations, the gain and level-density variations with time can be predicted. These fiber amplifiers have unstable conditions. In experiments, the decay of dye dopants in the high pump power regime has been observed. For example, in a high pump power rhodamine-B is converted from the zwitterion isomer to the colorless lactone isomer [1]. Therefore, for complete coincidence of theoretical and experimental results, this effect must be included in the analysis, which is however beyond the scope of this paper and will be discussed in the near future. PACS 42.60.Da; 42.81.Wg; 31.15.Fx; 33.80.-b; 42.55.WdAn erratum to this article can be found at     

Studies on 3,5-diaminopyrazole derivatives

The behaviour of 3,5-diamino-4-phenylazopyrazole toward a variety of reagents is reported. Several new 3,5-diaminopyrazole derivatives as well as amino derivatives of fused pyrazoles have been prepared.

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Untersuchungen an 3,5-Diaminopyrazol-Derivaten

Zusammenfassung Es wird über das Verhalten von 3,5-Diamino-4-phenylazopyrazol gegenüber verschiedenen Agentien berichtet. Es wurden sowohl einige neue 3,5-Diaminooyrazol-Derivate als auch einige Aminoderivate von kondensierten Pyrazolen dargestellt.