Variable Range Hopping in Hydrogenated Amorphous Silicon-Nickel Alloys

On the insulating side of the metal-insulator transition (MIT), the study of the effect of low Temperatures T on the electrical transport in amorphous silicon-nickel alloys a-Si1-yNiy:H exhibits that the electrical conductivity follows, at the beginning, the Efros-Shklovskii Variable Range Hopping regime (ES VRH) with T-1/2. This behaviour showed that long range electron-electron interaction reduces the Density Of State of carriers (DOS) at the Fermi level and creates the Coulomb gap (CG). For T higher than a critical value of temperature TC, we obtained the Mott Variable Range Hopping regime with T-1/4, indicating that the DOS becomes almost constant in the vicinity of the Fermi level. The critical temperature TC decreases with nickel content in the alloys.

Enhanced Thermal Stability of Promising Nano-Porous Silicon Powder

A direct synthesis method is introduced to prepare nano-porous silicon-nickel nanocomposite (nPS/Ni) powder for thermal isolation applications. In this paper, we study the thermal stability of nanocomposites consisting of nanoparticles metal incorporated into the pores of a porous silicon by a very simple method. The nickel element is chemically deposited whereas the nanoparticles are precipitated on the pore surfaces. The (nPS) and (nPS/Ni) nano-materials are thermally measured under nitrogen at temperatures of 40&#8451 - 1000&#8451, noticeable, demonstrating better thermal stability of (nPS/Ni) until 900&#8451 than in the case of (nPS) at 600&#8451. Then, the improving of the thermal stability of the nPS powder is facilitated using it in many applications of the thermal insulation process.

Positive Magnetoresistance in Hydrogenated Amorphous Alloys Silicon Nickel a-Si_1-yNiy:H at Very Low Temperature with Magnetic Field

We present results of an experimental study of magnetoresistance phenomenon in an amorphous silicon-nickel alloys a-Si1-yNiy:H:H (where y = 0.23) on the insulating side of the metal-insulator transition (MIT) in presence of magnetic field up to 4.5 T and at very low temperature. The electrical resistivity is found to follow the Efros-Shklovskii Variable Range Hopping regime (ES VRH) with T -1/2. This behaviour indicates the existence of the Coulomb gap (CG) near the Fermi level.

Validation of polymer-based nano-iron oxide in further phosphorus removal from bioeffluent： laboratory and scaled- up study

The efficient removal of phosphorous from water is an important but challenging task. In this study, we validated the applicability of a new commercially available nanocomposite adsorbent, i.e., a polymer-based hydrated ferric oxide nanocomposite （HFO-201）, for the further removal of phosphorous from the bioefftuent discharged from a municipal wastewater treatment plant, and the operating parameters such as the flow rate, temperature and composition of the regenerants were optimized. Labora- tory-scale results indicate that phosphorous in real bioeffluent can be effectively removed from 0.92 mg· L^-1 to 〈 0.5 mg· L^-1 （or even 〈 0.1 mg·L^-1 as desired） by the new adsorbent at a flow rate of 50 bed volume （BV） per hour and treatable volume of 3500-4000BV per run. Phosphorous removal is independent of the ambient temperature in the range of 15℃-40℃. Moreover, the exhausted HFO-201 can be regenerated by a 2% NaOH ＋ 5% NaC1 binary solution for repeated use without significant capacity loss. A scaled-up study further indicated that even though the initial total phosphorus （TP） was as high as 2 mg·L^-1, it could be reduced to 〈 0.5 mg·L^-1, with a working capacity of 4.4-4.8 g·L^-1 HFO- 201. In general, HFO-201 adsorption is a choice method for the efficient removal of phosphate from biotreated waste effluent.

Preparation of Molecularly Imprinted Electrochemical Sensor for Detection of Vincristine Based on Reduced Graphene Oxide/Gold Nanoparticle Composite Film

An innovative molecularly imprinted electrochemical sensor was fabricated based on reduced graphene oxide （RGO） and gold nanocomposite （Au） for rapid detection of vincristine （VCR）. The RGO-Au composite membrane was obtained via direct one-step electrodeposition technique of graphene oxide （GO） and chloroauric acid （HAuCl4） on the surface of a glassy carbon electrode （GCE） by means of cyclic voltammetry （CV） in the potential range be- tween -1.5 and 0.6 V in phosphate buffer solution （PBS） of pH 9.18, which is capable of effectively utilizing its superior electrical conductivity, larger specific surface area due to its synergistic effect between RGO and Au. The molecularly imprinted polymers （MIPs） were synthesized on the RGO-Au modified glassy carbon electrode surface with VCR as the template molecular, methyl acrylic acid （MAA） as the functional monomer, and ethylene glycol maleic rosinate acrylate （EGMRA） as a cross-linker. The performance of the sensor was investigated by cyclic voltammetry （CV）, differential pulse voltammetry （DPV） and electrochemical impedance spectroscopy （EIS） in de- tail. Under the optimum conditions, the fabricated sensor exhibited a linear relationship between oxidation peak current and VCR concentration over the range of 5.0×10 8 5.0×10^-6 mol.L l with a correlation coefficient of 0.9952 and a detection limit （S/N=3） of 2.6×10 8 mol.L^-1. The results indicated that the imprinted polymer films exhibited an excellent selectivity for VCR. The imprinted sensor was successfully used to determine VCR in real samples with recoveries of 90%-- 120% by using the standard addition method.

Preparation and property characterization of PAA/Fe_(3)O_(4) nanocomposite

PAA/Fe_(3)O_(4) nanocomposites were prepared by mixing nano-Fe_(3)O_(4) and polyacrylic acid(PAA)ethanol solution and then evaporating the solvent.The materials were characterized by transmission electron microscope(TEM),Fourier transform infrared spectroscope(FTIR),thermogra-vimetry analysis(TGA),dynamic ultra-micro hardness tester(DUMHT)and superconducting quantum interference device(SQUID)magnetometer.Results showed that PAA coordi-nated with nano-Fe_(3)O_(4) to form a cross-linking structure.The presence of nano-Fe_(3)O_(4) enhanced the thermal stability of the nanocomposite.The elasticity and hardness of the nanocomposite increased,and the indentation depth reduced with the increase of Fe_(3)O_(4) content in the composites.The nanocomposites showed superparamagnetic properties at 300 K.