Modification in structural,optical, morphological,and electrical properties of zinc oxide (ZnO) nanoparticles (NPs) by metal (Ni,Co) dopants for electronic device applications

In the present work, Zinc Oxide (ZnO) nanoparticles (NPs) were synthesized by the chemical co-precipitation method using Zinc Chloride as the initial chemical, while Nickel and Cobalt chloride as dopants. Phase identification of metal (Ni, Co) doped Zinc Oxide nanoparticles (NPs) was observed using x-ray diffraction (XRD). The small lattice distortion or phase changes appeared due to shifting of diffraction angles peaks towards larger angle in ZnO are corresponded to metal (Ni, Co) dopant. The average crystallite size appears to decrement in NP size from 7.67 nm to 6.52 nm and 5.35 nm to 5.17 nm with increasing 5 % to 80 % of metal (Ni, Co) dopant respectively. The optical characteristics, including the absorption spectra of the prepared sample were observed through UV–Vis spectroscopy, Meanwhile SEM confirmed the observation of composition change in specimen with metal (Ni, Co) dopant concentration. The bandgap value was also found decrement 5.23 eV to 5.05 eV with increment of metal (Ni, Co) dopant concentration. The functional groups were measured by Fourier transformation infrared spectroscopy (FTIR). FTIR peaks found the metal (Ni, Co) doped ZnO with the vibration mode of (Zn²⁺ –O^2?) ions due to the increment of dopant concentrations. Furthermore, electrical results show the ohmic behavior of prepared samples. These findings indicate the possibility of tuning optical, structural and electrical properties of metal (Ni, Co) doped ZnO with various dopant concentrations of Nickel and will have great potential to find application in optoelectronic devices.     

Optical Nonlinearity of Emerging ZrS2 and HfS2 Semiconductors

Compatible with existing processing technology, chemical vapor deposition method is used to synthesize ZrS₂ and HfS₂ films a a large scale. The nonlinear optical properties are characterized by Z-scan measurement with femtosecond pulses at 800 nm. The results show that saturable absorption happens in ZrS₂ owing to the larger ground state absorption than the excited state absorption, while reverse saturable absorption appears in HfS₂ due to the two-photon absorption. The figure of merit values of ZrS₂ (≈4.30 ± 0.12 × 10⁻¹⁵ esu cm) and HfS₂ (≈6.0 ± 1.4 × 10⁻¹⁵ esu cm) are much larger than those of MoS₂ and graphene in ultrafast nonlinear optical performance at the wavelength of 800 nm.     

Two identical conducting spheres with same potential in a uniform electric field

Interaction, polarization, and charges or electric field distribution of conducting spheres in applied electric field are in many fields including electrorheological fluids, electrophoresis, and electrical engineering. A system with two equipotential conducting spheres in an applied uniform electric field is analyzed by image method. A new method is put forward to calculate the image charges distribution when using image method, which ensures the validity of image method to analyze equipotential cases. An apparatus is constructed to measure the force experimentally as well. Results show that the distribution of electric field and electric interaction are different with the case not equipotential.     

TG-assisted determination of pyrene solubility in 1-pentanol

Thermogravimetry technique was used to analyze the composition of saturated solution in the measurement of solubility of pyrene in 1-pentanol. A proper heating curve was designed in order to evaporate solvent with a high speed completely and at the same time keep solute mass unchanged. The measured solubility was close to the data measured by traditional laser monitoring observation technique. The experimental data were correlated with the Apelblat model. The calculated values of Apelblat model were found to show a fine representation of the experimental data. Then the dissolution enthalpy and entropy of pyrene were predicted from the solubility data using van’t Hoff equation.     

Preparation and characterization of a novel dual‐retention mechanism mixed‐mode stationary phase with PEG 400 and succinic anhydride as ligand for protein separation in WCX and HIC modes

A novel dual‐retention mechanism mixed‐mode stationary phase based on silica gel functionalized with PEG 400 and succinic anhydride as the ligand was prepared and characterized by infrared spectra and elemental analysis. Because of the ligand containing PEG 400 and carboxyl function groups, it displayed hydrophobic interaction chromatography (HIC) characteristic in a high‐salt‐concentration mobile phase, and weak cation exchange chromatography (WCX) characteristic in a low‐salt‐concentration mobile phase. As a result, it can be employed to separate proteins with both WCX and HIC modes. The resolution and selectivity of the stationary phase was evaluated under both HIC and WCX modes with protein standards, and its performance was comparable to that of conventional ion‐exchange chromatography and HIC columns. The results indicated that the novel dual‐retention mechanism column, in many cases, could replace two individual WCX and HIC columns as a ‘2D column’. In addition, the mixed retention mechanism of proteins on this ‘2D column’ was investigated with stoichiometric displacement theory for retention of solute in liquid chromatography in detail in order to understand why the dual‐retention mechanism column has high resolution and selectivity for protein separation under WCX and HIC modes, respectively. Based on this ‘2D column’, a new 2DLC technology with a single column was developed. It is very important in proteome research and recombinant protein drug production to save column expense and simplify the processes in biotechnology. Copyright © 2013 John Wiley & Sons, Ltd.     

A multi-phase level set framework for source reconstruction in bioluminescence tomography

We propose a novel multi-phase level set algorithm for solving the inverse problem of bioluminescence tomography. The distribution of unknown interior source is considered as piecewise constant and represented by using multiple level set functions. The localization of interior bioluminescence source is implemented by tracing the evolution of level set function. An alternate search scheme is incorporated to ensure the global optimal of reconstruction. Both numerical and physical experiments are performed to evaluate the developed level set reconstruction method. Reconstruction results show that the proposed method can stably resolve the interior source of bioluminescence tomography.     

Quantitative HPLC method and pharmacokinetic studies of ergosta‐4,6,8(14),22‐tetraen‐3‐one,a natural product with diuretic activity from Polyporus umbellatus

A simple and specific HPLC method with dual wavelength UV detection for the determination of ergosta‐4,6,8(14),22‐tetraen‐3‐one (ergone) in rat plasma was developed and proved to be efficient. The method used ergosterol as internal standard (IS). Following a single‐step protein precipitation, the analyte and IS were separated on an Inertsil ODS‐3 column with a mobile phase containing methanol–water (99:1, v/v) at a flow rate of 1 mL/min. The analytes were detected by using UV detection at wavelength of 350 (ergone) and 283 (IS) nm, respectively. The calibration curve was linear over the range of 0.1–2.0 µg/mL and the lower limit of quantification was 0.1 µg/mL. The intra‐day and inter‐day precision studies showed good reproducibility with RSD less than 8.5%. The intra‐day and inter‐day accuracy ranged from 95.6 to 104%. Mean extraction recovery was above 95% at the low, medium and high concentrations. The present HPLC‐UV method was simple and reliable. The method described herein had been successfully applied for the pharmacokinetic studies in male SD rats after administration of 20 mg/kg dose of solution of ergone. Copyright © 2010 John Wiley & Sons, Ltd.     

Syntheses,crystal structures and magnetic properties of transition metal compounds with the 3-pyridylphosphonato ligand

Treatment of 3-pyridylphosphonic acid with Cu(OAc)₂·H₂O under hydrothermal conditions afforded the complex [Cu(η⁴,μ⁴:3-C₅H₄NPO₃)] (1), whereas the analogous reaction with Co(OAc)₂·4H₂O gave [Co(3-C₅H₄NPO₃)(H₂O)₅] (2) in good yield. Compounds 1 and 2 have been characterized by IR, elemental analyses and X-ray crystallography. Compound 1 shows a two-dimensional layer structure, in which each Cu center bridges to another Cu center via two pyridylphosphonato oxygen atoms of bridging ligands to form a one-dimensional ladder of {CuO₃N}{CPO₃} units. The pyridyl N atom further coordinates to the Cu center in the neighboring chain, thus forming a two-dimensional layer. Compound 2 contains molecules of [Co(3-C₅H₄NPO₃)(H₂O)₅] which link each other via hydrogen bonds to form a three-dimensional super-molecular framework. Complex 1 shows weak antiferromagnetic interactions between the closest copper centers.     

Decolorization of acid red B aqueous solution by positive and negative electrical discharge

We investigated the decolorization of acid red B in aqueous solution by atmospheric discharge. It was found that decolorization was significantly greater when the aqueous solution served as the cathode than when it served as the anode. Our investigation suggests that hydroxyl radicals could be a major factor for decolorization in the solution phase. An analysis of the energy transportation by charge carriers in the discharge processes revealed that the mean energy transported from positive ions to the aqueous cathode was considerably higher than that transported from electrons/negative ions to the aqueous anode, and this could probably have indirectly affected the decolorization.