Multiple-beam interference fringes applied to investigate the index profile of the optical fiber dip

A numerical-based phase shift method is presented to study optical fibers having a dip in the refractive index profile at the center of the core. Mathematical expressions for the shape of multiple-beam Fizeau fringes crossing a graded-index optical fiber (GRIN) comprising a central graded-index dip or GRIN fiber with a constant refractive index dip, immersed in a silvered liquid wedge, are derived. The index profile parameters of the central dip are determined by comparing the theoretical fringe shape across the fiber cross-section and the experimental fringe shape obtained from micro-interferograms of the wedge interferometer.     

Glow discharge plasma electrolysis for nanoparticles synthesis

There are many methods available to synthesize nanomaterials and the glow discharge plasma electrolysis is a novel and a green method in this category. It is seen that most of the papers are published after 2005 and the interest in it is growing due to its applicability in the industry for preparing nanomaterials at large scale. But, only few results are available yet and most of them are on metal nanoparticle preparation, so that more studies are needed to understand the nature of growth of the nanoparticles under glow discharge in liquid and its applicability in preparing semi-conductor nanomaterials. Many have tried many methods to prepare nanoparticles by the glow discharge and a review like this is the need of the time to understand its present status that helps to modify the present situation to a better one. This review classifies all the available methods of nanomaterials synthesis in liquid by glow discharge in to three and it is discussed in detail.     

On completely integrable coupled Burgers and coupled Korteweg–de Vries systems

In this work, we study two completely integrable equations, namely, coupled Burgers and Korteweg–de Vries systems. The modified form of Hirota’s bilinear method, established by Hereman, is employed to formally derive multiple-soliton solutions and multiple-singular-soliton solutions for each system. Hirota’s bilinear method is reliable and effective and can also be applied to solve other types of higher-dimensional integrable and non-integrable systems.     

Characterization of Mn doped ZnS nanocrystalline powder dispersed in polyvinyl alcohol: 1st Nano Update

Manganese doped zinc sulfide nanocrystalline powder was synthesized with sodium citrate and its films were formed by mixing it with polyvinyl alcohol to study optical absorption of Mn doped ZnS dispersed in polyvinyl alcohol. The characteristics of the prepared powder and film samples were studied by X-ray diffraction, transmission electron microscopy and UV–visible absorption spectroscopy. Samples exhibited optical absorption at lower wavelength region and particle sizes were calculated from X-ray diffractogram.     

A Versatile Synthesis,PM3‐Semiempirical,Antibacterial, and Antitumor Evaluation of Some Bioactive Pyrazoles

This research work describes the synthesis and biological properties of some novel isolated or fused heterocyclic ring systems with pyrazole, for example; enaminones containing pyrazolone ring photochromic functional unit, 4‐[(4‐chlorophenylamino)methylene]‐3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐one (3) and some analogous derivatives 4, 9, and 10, also as pyrazolo[3,4‐b]pyridine, pyrazolo[3,4‐b]quinoline, pyrazolo[3′,4′:4,5]thieno[2,3‐c]pyrazoline and pyrazolo[3,4‐c]pyrazole were synthesized and characterized. Newly synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR, mass spectral data and quantum mechanical calculations. Selected products were tested for their antibacterial and antitumor agents.     

High-performance liquid chromatography quantification of principal antioxidants in black seed (Nigella sativa L.) phytopharmaceuticals

A new, simple, sensitive, rapid, and accurate isocratic RP-HPLC method was developed and validated for simultaneous analysis of the principal antioxidants of Nigella sativa, i.e., thymoquinone (TQ), carvacrol (CR), and its isomer thymol (THY), in different phytopharmaceuticals. The mobile phase was water-methanol (40 + 60, v/v) at a flow rate of 1.5 mL/min. Quantification was achieved with UV detection at 254 nm, based on peak area. The method was validated for linearity, accuracy, precision, selectivity, and robustness. The proposed method is stability-indicating for determination of TQ in the presence of its degradants. The LOD and LOQ (microg/mL) were, respectively, 0.006 and 0.021 for TQ, 0.002 and 0.006 for CR, and 0.027 and 0.090 for THY. The mean recoveries measured at three concentrations were higher than 99%, with RSD <2%. This analytical method is suitable for quality control of the marker substances in this widely used natural protective and curative remedy.     

Effect of Li2O doping on electrical properties of CoFe2O4

The solid–solid interactions between cobalt and ferric oxides to produce CoFe₂O₄ were followed up using XRD investigation. The effect of Li₂O-doping on the ferrite formation was also studied. The electrical and dielectric parameters of pure and doped mixed solids precalcined at 1273 K were measured using d.c and a.c instruments.The dopant concentration was varied between 0.5 and 6 mol% Li₂O. The results obtained revealed that Li₂O doping much enhanced the ferrite formation due to an increase in the mobility of the reacting species.

The addition of the smallest amount of Li₂O (0.5 mol%) resulted in measurable variations in the electrical constants (ρ, E_a, ′, ″ and tan δ). Resistivity increased upon increasing the dopant concentration up to 1.5 mol% exceeding the values measured for the undoped sample. Furthermore, the presence of 6 mol% Li₂O brought about a significant decrease of electrical resistivity. Also, the activation energy decreased with increasing the dopant concentration. The dielectric constant behaves according to ε=const. 1/ρ^1/2.

The Li₂O-doping modified the values of different dielectric constants, the change in these constants was found to be strongly dependent on the amount of Li₂O added.These results have been discussed in terms of the potentiality of Li₂O in increasing the mobility of the reacting species involved in the ferrite formation.     

Cu(II)‐promoted cyclization of hydrazonophthalazine to triazolophthalazine; Synthesis and structure diversity of six novel Cu(II)‐triazolophthalazine complexes

A novel route for the synthesis of Cu(II)‐triazolophthalazine complexes using the Cu(II)‐promoted cyclization dehydrogenation reactions of hydrazonophthalazines under reflux was presented. Two hydrazonophthalazines were cyclized to the corresponding triazolophthalazine ligands, 3‐pyridin‐2‐yl‐3,10b‐dihydro‐[1,2,4]triazolo[3,4‐a]phthalazine ( TPP ) and 3‐(3,10b‐dihydro‐[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐benzoic acid ( TP3COOH ), followed by in situ complexation with Cu(II) yielding six novel Cu(II)‐triazolophthalazine complexes depending on the reaction conditions. The molecular and supramolecular structures of the Cu(II)‐triazolophthalazine complexes were discussed. The metal sites have rectangular pyramidal geometry in the [Cu(TPP)Cl₂]₂; 1 and [Cu(TP3COOEt)Cl₂(H₂O)]₂; 4 dinuclear complexes, distorted square planar in [Cu(TP3COOMe)₂Cl₂]; 3 , [Cu(TP3COOH)₂Cl₂]; 5 and [Cu(TP3COOH)₂Cl₂]·H₂O; 6 and a distorted octahedral in [Cu(TPP)(H₂O)₂(NO₃)₂]; 2 . Hirshfeld analysis showed that the O…H, C…H, Cl…H (except TP3COOH and 2 ), N…H and π‐π stacking interactions are the most important intermolecular contacts. The π‐π stacking interactions are the maximum for TP3COOH and complex 6 with net C…C/C…N contacts of 19.4% and 15.4%, respectively. The orbital–orbital interaction energies of the Cu‐N/Cu‐Cl bonds correlated inversely with the corresponding Cu‐N/Cu‐Cl distances, respectively. The charge transfer processes between Cu(II) and ligand groups were also discussed. The charge densities of the Cu(II) centers are reduced to 0.663–0.995 e due to the interactions with the ligand groups coordinating it.     

Mono- and penta-nuclear self-assembled silver(I) complexes of pyrazolyl s-triazine ligand; synthesis,structure and antimicrobial studies

The self-assembled [Ag (PTDM)NO₃] ( 1 ), [Ag (PTDM)₂(H₂O)]ClO₄^.H₂O ( 2 ) and [Ag₅(PTDM)₄(H₂O)₆(ClO₄)₄]ClO₄^.2H₂O ( 3 ) complexes were synthesized by the direct mixing of AgX (X = NO₃¯ or ClO₄¯) and 4,4′-[6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4-diyl]dimorpholine ( PTDM ) ligand in water–methanol mixture. The coordination numbers of silver range from three to five. Complex 3 is a rare case in which one nitrogen atom from the same s-triazine core of the PTDM ligand has a μ(1,1) bridging mode between Ag1 and Ag2 in the penta-nuclear array with Ag1–N1 and Ag2–N1 distances of 2.666(4) and 2.418(3) Å, respectively. Its 3D topology has a kind of primitive dense packing derived from the α-Po type structure. Hirshfeld analysis showed that the percentages of the O^…H hydrogen bonds were 32.4, 25.4, and 42.0% in complexes 1 – 3 , respectively. While the ligand showed no antimicrobial activity at the applicable concentration, the penta-nuclear complex 3 had higher antibacterial (MIC = 3.7 μmol/L) and antifungal (14.6 μmol/L) potencies toward the tested microbes compared with complexes 1 and 2 . Also, the killing doses of 3 were in the range of 7.3–58.5 μmol/L compared with 18.2–291.1 and 20.1–160.6 μmol/L for 1 and 2 , respectively. It is clear that the higher Ag-content in 3 could be the main reason for its higher antimicrobial activity.     

Erratum to “Simultaneous effects of magnetic field and space porosity on compressible Maxwell fluid transport induced by a surface acoustic wave in a microchannel”

We would like to acknowledge the misprinted terms in our published paper “Simultaneous effects of magnetic field and space porosity on compressible Maxwell fluid transport induced by a surface acoustic wave in a microchannel” [Chin. Phys. B 22 124702 (2013)]. Since only two misprints exist and the main results of the published paper are correct, we present the correct equations in this erratum.