Synthesis and characterization of Ag-doped p-type ZnO nanowires

P-type ZnO nanowires with silver (Ag) doping were synthesized via a chemical vapor deposition process. The incorporation of Ag was confirmed by selected-area energy-dispersive x-ray spectroscopy. The formation of acceptor states was demonstrated by temperature and excitation power-dependent photoluminescence measurements. Characterization of field-effect transistors using Ag-doped ZnO nanowires as channels showed p-type conductivity of the nanowires with a hole concentration of 4.9×10¹⁷ cm⁻³ and a carrier mobility of approximately 0.18 cm² V⁻¹ s⁻¹.     

Some research problems on the hadamard product and singular values of matrices

We pose some problems on the Hadamard product and singular values of matrices.     

LC–MS/MS method for the simultaneous determination of ethyl gallate and its major metabolite in rat plasma

A simple, rapid and sensitive liquid chromatography–tandem mass spectroscopy (LC–MS/MS) method was developed and validated for the determination of ethyl gallate, a pharmacologically active constituent isolated from Lagerstroemia speciosa (Linn.) Pers. This method was used to examine the pharmacokinetics of ethyl gallate and its major metabolite gallic acid in rat plasma using propyl gallate as an internal standard. After precipitation of the plasma proteins with acetonitrile, the analytes were separated on a Zorbax SB‐C₁₈ column (3.5 μm, 2.1 × 50 mm) with an isocratic mobile phase consisted of methanol–acetonitrile–10 mM ammonium acetate (10 : 25 : 65, v/v/v) containing 0.1% formic acid at a flow rate of 0.25 mL/min. The Agilent G6410A triple quadrupole LC/MS system was operated under the multiple‐reaction monitoring mode using the electrospray ionization technique in negative mode. The lower limits of quantification of gallic acid and ethyl gallate of the method were 0.5 and 1.0 ng/mL. The intra‐day and inter‐day accuracy and precision of the assay were less than 8.0%. This method has been applied successfully to a pharmacokinetic study involving the intragastric administration of ethyl gallate to rats. Copyright © 2009 John Wiley & Sons, Ltd.     

Lagrangian approach for dark soliton in nonlocal nonlinear media

We theoretically investigate the dynamics of dark solitons as well as their interaction in nonlocal media. Approximate equations describing the evolution of the beams are obtained via suitable trial functions of amplitude u and refractive index n in an averaged Lagrangian. Our results reveal that out-of-phase dark solitons can evolve into stable bound states in nonlocal materials. Moreover, it is found that the separations in the bound state monotonically increase with the degree of nonlocality in nonlocal limit. These results are in excellent agreement with the numerical simulations.     

Agent-based modelling and simulation of urban evacuation: relative effectiveness of simultaneous and staged evacuation strategies

This study investigates the effectiveness of simultaneous and staged evacuation strategies using agent-based simulation. In the simultaneous strategy, all residents are informed to evacuate simultaneously, whereas in the staged evacuation strategy, residents in different zones are organized to evacuate in an order based on different sequences of the zones within the affected area. This study uses an agent-based technique to model traffic flows at the level of individual vehicles and investigates the collective behaviours of evacuating vehicles. We conducted simulations using a microscopic simulation system called Paramics on three types of road network structures under different population densities. The three types of road network structures include a grid road structure, a ring road structure, and a real road structure from the City of San Marcos, Texas. Default rules in Paramics were used for trip generation, destination choice, and route choice. Simulation results indicate that (1) there is no evacuation strategy that can be considered as the best strategy across different road network structures, and the performance of the strategies depends on both road network structure and population density; (2) if the population density in the affected area is high and the underlying road network structure is a grid structure, then a staged evacuation strategy that alternates non-adjacent zones in the affected area is effective in reducing the overall evacuation time.     

Synthesis,electrochemical and an e.s.r study of heterodinuclear MIIZnII (M = Cu,Ni, and VO) complexes of asymmetric macrocyclic ligands made from 2,6-diacetyl-4-methylphenol

A series of heterodinuclear complexes, [MZnL][ClO4)2· nH2O (M = Cu, Ni, and VO) where L is a dinucleating Schiff base ligand derived from the condensation of 2,6-diacetyl-4-methylphenol (1mole), with ethylenediamine (1mole), 1,2-diaminopropane (1mole), or 1,3-diaminopropane (1mole) have been synthesized and evaluated. The complexes exhibit a single one-electron redox couple as anticipated. The e.s.r spectra for the CuZn complex shows an isotropic signal and the frozen glass spectra of VOZn complex is characterized by two sets of eight lines.     

Solvatochromic Behavior of Chiral Mesoporous Metal–Organic Frameworks and Their Applications for Sensing Small Molecules and Separating Cationic Dyes

Two anionic metal–organic frameworks (MOFs) with 1D mesoporous tubes ( 1 ) and chiral mesoporous cages ( 2 ) have been rationally constructed by means of a predesigned size‐extended hexatopic ligand, namely, 5,5′,5′′‐(1,3,5‐triazine‐2,4,6‐triyl)tris‐ (azanediyl)triisophthalate (TATAT). Charge neutrality is achieved by protonated dimethylamine cations. Notably, the two MOFs can be used to separate large molecules based on ionic selectivity rather than the size‐exclusion effect so far reported in the literature. Owing to the imino triazine backbone and carboxyl groups of the hexatopic ligand, which provide important host–guest interactions, rare solvatochromic phenomena of 1 and 2 are observed on incorporating acetone and ethanol guests. Furthermore, guest‐dependent luminescence properties of compound 2 were investigated, and the results show that luminescence intensity is significantly enhanced in toluene and benzene, while quenching effects are observed in acetone and ethanol. Thus, compound 2 may be a potential material for luminescent probes.     

Linearized oscillation theorems for neutral difference equations

Consider the nonlinear neutral difference equation {fx149-1} We establish a linearized oscillation theorem which is a discrete result of the open problem by Gyori and Ladas. This work is partially supported by NNSF (NO: 19671027) of China.