Indium phosphide nanofibers prepared by electrospinning method: Synthesis and characterization

Nine sets of (3 × 3) InP nanofiber samples have been successfully prepared at three different voltages (20, 25, 30 kV) and at three separate heights (5, 7, 10 cm) by electrospinning with a constant precursor flow rate of 0.3 mLh⁻¹. The crystalline structure, thermal, morphologies and nanostructure, electrical, and optical properties of the samples are characterized by X‐ray powder diffractometer (XRD) and thermal gravity‐differential scanning calorimeter (TG‐DSC), scanning electron microscopy (SEM), by Four‐Point Probe Technique (FPPT,) and ultraviolet/visible spectrometry (UV/VIS), respectively. From these measurements, we have found the formation of stoichiometric nanostructured InP with zinc‐blende structure and having lattice parameter of a = 5.874 Å, weight loss of 64.59% and crystallization temperature of 500°C, average fiber diameter of 65.82 nm, the activation energies, E_a, of the samples, and band gap energy, E_g, of the nanofibers developed at constant applied voltage 30 kV. The band gap energies determined at different distances 5, 7, and 10 cm are found to be as 1.29, 1.37, and 1.30 eV, respectively.     

NMR, UV, FT-IR, FT-Raman spectra and molecular structure (monomeric and dimeric structures) investigation of nicotinic acid N-oxide: A combined experimental and theoretical study

In this work, the experimental and theoretical UV, NMR, and vibrational features of nicotinic acid N-oxide (abbreviated as NANO, C(6)H(5)NO(3)) were studied. The ultraviolet (UV) absorption spectrum of studied compound that dissolved in water was examined in the range of 200-800nm. FT-IR and FT-Raman spectra in solid state were observed in the region 4000-400cm(-1) and 3500-50cm(-1), respectively. The (1)H and (13)C NMR spectra in DMSO were recorded. The geometrical parameters, energies and the spectroscopic properties of NANO were obtained for all four conformers from density functional theory (DFT) B3LYP/6-311++G(d,p) basis set calculations. There are four conformers, C(n), n=1-4 for this molecule. The computational results identified the most stable conformer of title molecule as the C1 form. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. (13)C and (1)H nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, absorption wavelengths, HOMO and LUMO energies, were performed by CIS approach. Finally the calculation results were applied to simulate infrared, Raman, and UV spectra of the title compound which show good agreement with observed spectra.     

Effect of indium incorporation on the optical properties of spray pyrolyzed Cd0.22Zn0.78S thin films

In this study, effect of indium incorporation on the optical properties is investigated for the spray pyrolyzed onto glass substrates at 275°C substrate temperature undoped and indium doped Cd_0.22Zn_0.78S thin films. The average optical transmittance of all the films was over 77% in the wavelength range between 450 and 800 nm. The optical band gap energies of the thin films have been investigated by the measurement of the optical absorbance as a function of wavelength. The optical absorption studies reveal that the transitions are direct band gaps of 3.02 and 3.05 eV for undoped and doped indium Cd_0.22Zn_0.78S thin films, respectively. The Urbach tail parameter and optical constants such as refractive index, extinction coefficient, and dielectric constants were calculated for these films. The dispersion parameters such as single-oscillator energy and dispersive energy were discussed in terms oft he single-oscillator Wemple—DiDomenico model.     

Analysis of an M/G/∞ queue with batch arrivals and batch-dedicated servers

We analyze an M/G/∞ queue with batch arrivals, where jobs belonging to a batch have to be processed by the same server. The number of jobs in the system is characterized as a compound Poisson random variable through a scaling of the original arrival and batch size processes.     

Electrochemical Determination of Copper(II) in Water Samples Using a Novel Ion-Selective Electrode Based on a Graphite Oxide–Imprinted Polymer Composite

A novel copper(II)-selective electrode based on graphite oxide/imprinted polymer composite was developed for the electrochemical monitoring of copper(II) (Cu²⁺) ions. The electrode exhibited highly selective potentiometric response to Cu²⁺ with respect to common alkaline, alkaline earth and heavy metal cations. The composite composition studies indicated that the most suitable composite composition performing the most promising potentiometric properties was 20.0% ionophore (Cu²⁺-ion imprinted polymer), 10.0% paraffin oil, 5.0% multiwalled carbon nanotubes, and 65.0% graphite oxide. The fabricated electrode exhibited a linear response to Cu²⁺ over the concentration range of 1.0?×?10^??6–1.0?×?10^??1?M (correlation coefficient of 0.9998) with a sensitivity of 26.1?±?0.9?mV decade^??1. The detection limit of the fabricated electrode was determined to be 4.0?×?10^??7?M. The electrode worked well in the pH range of 4.0–8.0. The electrode had stable, reversible and fast potentiometric response (3?s). In addition, the electrode had a lifetime of more than 1 year. The analytical applications of the proposed electrode were performed using as an indicator electrode for the potentiometric titration of Cu²⁺ with ethylene diamine tetraacetic acid solution and for the determination of Cu²⁺ of spiked river, dam, and tap water samples. The obtained results for potentiometric titration and water samples were satisfactory.     

Polymerlzatlon of 1-Ethynyl-1-Cyclohexanol by Radiation,Electroinitiation, and Chemical Catalysts

Abstract

Solid-state polymerization of 1-ethynyl-1-cyclohexanol was carried out by irradiation in vacuum and in open air at 20°C. Radiation-induced polymerization was also done in a benzene solution. The products were mixtures of oligomers and polymers. IR, NMR, U V, and x-ray investigations showed the initial formation of trimer, oligomer, and polymer. The polymer fraction increased with an increase of conversion. Electro-initiated polymerization gave soluble and insoluble fractions. The soluble fraction was an ether. However, the results were not reproducible. No polymers were obtained with n-butyllithium and borontrifluoride etherate as chemical catalysts.     

A model proposal for the chaotic structure of Istanbul stock exchange

Chaos theory is considered a novel way of understanding the behaviour of nonlinear dynamic systems. It is well known that the evaluation of chaotic systems is dependent on initial conditions since exponential growth error is a common characteristic. This present paper evaluates the effects of a nonlinear dynamic system in Istanbul Stock Exchange, based on time series. The reliability of predicting stock behaviour depends on this fact. In other words, the aim is to prove that if ISE daily index return shows chaotic behaviour.     

Electrical coupling in proton exchange membrane fuel cell stacks: mathematical and computational modelling

^** Corresponding author. Email: wetton{at}math.ubc.ca^*** Email: Peter.Berg{at}uoit.ca^**** Email: caglara{at}uwgb.edu^***** Email: kpromisl{at}math.msu.edu^****** Email: jean.st-pierre{at}ballard.com A mathematical model describing the effects of electrical couplingof proton exchange membrane unit fuel cells through shared bipolarplates is developed. Here, the unit cells are described by simple,steady-state, 1D models appropriate for straight reactant gaschannel designs. A linear asymptotic version of the model isused to give analytic insight into the effect of the coupling,including estimates of the extent of the coupling in terms ofthe number of adjacent cells affected. An efficient numericalmethod is developed to solve the non-linear coupled system.Numerical results showing the effects on stack voltage due toa single cell with anomalous oxidant flow rate are given. Theeffects on stack performance due to end plate effects are alsogiven. It is shown that electrical coupling has a significanteffect on fuel cell performance.     

Maxim GMSL SerDes器件的预加重和均衡

发送端的预加重和接收端的均衡能够使串行器/解串器(SerDes)采用廉价的电缆传输数据或延长数据传输距离。本文介绍了电缆对信号传输的影响,以及如何补偿。此外,文章介绍了使用有损电缆时,如何利用Maxim的多媒体串行链路(GMSL)产品构建可靠链路。本文还简要介绍了线路均衡技术。