Low-temperature polymer-assisted synthesis of shape-tunable zinc oxide nanostructures dispersible in both aqueous and non-aqueous media

We report the shape-controlled synthesis of zinc oxide (ZnO) nanostructures by a poly(vinyl methyl ether) (PVME)-assisted alkaline hydrolysis of zinc acetate at low temperature (20 °C). In this method, ZnO nanostructures of various morphologies including dumbbells, lances and triangles have been successfully prepared via a simple variation of different reaction parameters such as polymer concentration, pH of the reaction mixture and precursor concentration. However, without PVME, ZnO of such structurally uniform morphologies were not formed; rather ZnO of a mixture of defined and undefined morphologies were obtained indicating PVME-assisted the growth of such regular shaped ZnO nanostructures. HRTEM analysis of lance- and triangle-shaped samples as well as SAED patterns of all kinds of samples (dumbbell, lance and triangle) revealed that the ZnO nanostrcutures are single crystalline in nature and might form through oriented growth. XRD analysis also revealed the formation of well crystalline ZnO with a hexagonal structure. FTIR spectroscopy and TGA analysis confirmed the adsorption of PVME on the surface of ZnO nanostructures. Being a solvent adaptable polymer, the adsorbed PVME makes these shaped ZnO nanostructures highly dispersible in both polar and non-polar organic solvents including water. The extent of dispersibility in different solvents was studied by spectroscopic and microscopic techniques. Such solvent adoptability of PVME-coated ZnO nanostructures increases its ease of applications in device fabrication as well as in biological systems.     

Determination of traces of hafnium in zirconium oxide by wavelength dispersive X-ray fluorescence spectrometry

An accurate and precise wavelength dispersive X-ray fluorescence spectrometric method is described for the quantitative analysis of hafnium impurities in zirconium oxide matrix in the range from 6.8 to 1004 g/g, using the HfL₁ line on 8420⁺ XRF Quantometer (ARL) with LiF (220) crystal and scintillation detector. The practical limit of measurement is 6.8 g/g. The precision is between 1 to 6% for higher and lower concentrations of hafnium, whereas accuracy in most cases is <5%.     

Laser produced soft x-ray spectra of silver

Spectral lines corresponding to the transitions 3d¹⁰4s - 3d¹⁰np, 3d¹⁰4s² - 3d¹⁰4snp and 3d¹⁰4s²4p - 3d¹⁰4s²nd, 3d¹⁰4s²ns of Ag XIX - Ag XVII have been identified in a laser produced soft X-ray spectrum of silver by computing the transition energies with the help of a self-consistent field, Hartree-Fock-Slater code and by extrapolation of our previous observations regarding the state of ionization of the plasma in the cases of Mg, Al, Fe and Cu.     

Measurement and analysis of the excitation functions for alpha particle induced reactions on niobium

Stacked foil activation technique and Ge(Li) gamma ray spectroscopy have been used for determining the excitation functions up to 45 MeV, of six reactions⁹³Nb[(α, n), (α, 2n) ^m , (α, 2n) ^g , (α, 3n), (α,p3n) and (α, αn)]. Excitation functions were also calculated theoretically by means of the hybrid model with and without the inclusion of pre-equilibrium emission of particles. A general agreement was found in (α, xn) type of reactions.     

The Synthesis of 4,11,18,25-Tetrachloro [14]metacyclophane-7,14,21,28-tetroi,Structural Analogues of Phloroglucides

The synthesis of the title compounds is described. Some of the compounds prepared exhibited antimicrobial activity in vitro. Structure-activity relationship is briefly discussed.     

Mini ozonizer for instant production of ozone required for oxidation reactions and its application in the foam flotation-separation technique

The fabrication of a mini ozonizer and its application in the foam flotation-separation technique are described. The system rapidly generates ozone for instant use in small-scale oxidation processes. Its application to the separation of Ce(III) from an alkaline solution is demonstrated.     

Extraction of mercury from aqueous iodide solutions by trilaurylamine N-oxide and its subsequent determination by atomic absorption spectrometry

A solvent extraction technique using 0.01M solution of trilaurylamine N-oxide in benzene as extractant has been used to concentrate mercury efficiently from water solutions with or without the presence of 0.02M KI in weakly acidic media. In addition to unmodified aqueous solutions, mercury can be extracted quantitatively from aqueous iodide solutions that are up to 1M in HCl, H₂SO₄, and HNO₃ in a single equilibration. Distribution coefficients and separation factors of several elements relative to mercury(II) are reported for media that contain 0.1 M HCl and 0.02M KI. The reagent is superior to aliphatic amines and quaternary amines for the extraction of mercury from aqueous iodide solutions.