Search results for "PLASMA"
showing 10 items of 4043 documents
Tunable morphologies of ZnO films via the solution precursor plasma spray process for improved photocatalytic degradation performance
2018
Abstract The Solution Precursor Plasma Spray (SPPS) process is a novel, versatile and one-step route for building photocatalytic films. Herein, the influence of the precursor solution composition on the microstructure and on the properties of ZnO films prepared via the SPPS process was studied. Nanostructured ZnO particles (i.e. nanorods (NRs) and nanowires (NWs)) were obtained by using a solution of pure Zn(OAc)2 rather than pure Zn(NO3)2. Upon adding urea to the Zn(NO3)2 solution, NRs structured ZnO films were formed as well. The addition of acetic acid into the Zn(OAc)2 solution led to a damage of the nanostructured morphologies likely due to the inhibition of the zinc-containing cluster…
New process of silicon carbide purification intended for silicon passivation
2017
Abstract In this work, we report on a new, efficient and low cost process of silicon carbide (SiC) powder purification intended to be used in photovoltaic applications. This process consists on the preparation of porous silicon carbide layers followed by a photo-thermal annealing under oxygen atmosphere and chemical treatment. The effect of etching time on impurities removal efficiency was studied. Inductively coupled plasma atomic emission spectrometry (ICP-AES) results showed that the best result was achieved for an etching time of 10 min followed by gettering at 900 °C during 1 h. SiC purity is improved from 3N (99.9771%) to 4N (99.9946%). Silicon carbide thin films were deposited onto s…
Minority Carrier Lifetime Variations in Multicrystalline Silicon Wafers with Temperature and Ingot Position
2017
The minority carrier lifetimes of multicrystalline silicon wafers are mapped using microwave photoconductive decay for different temperatures and ingot positions. Wafers from the top of the ingot display larger areas with lower lifetimes compared to wafers from the bottom. The lifetimes of low-lifetime areas are found to increase with the temperature, while the lifetimes of some high-lifetime areas decrease or remain unchanged. The relative improvement of the low-lifetime areas is considerably larger than the relative change in the high-lifetime areas. We suggest that the above-mentioned observations explain, at least partially, why previous studies have found the relative temperature coeff…
Thermoelectric properties of spark-plasma sintered nanoparticular FeSb2prepared via a solution chemistry approach
2013
Nanoparticular FeSb2 was prepared in solution from cyclopentadienyl iron(ii) dicarbonyl dimer [Fe(Cp(CO)2)]2 and antimony nanoparticles. Spark plasma sintering was used as consolidation method to maintain the particle size. The thermoelectric performance of FeSb2 is limited by its high thermal conductivity. In this work, the thermal conductivity was suppressed by nearly 80% compared to the bulk value by introducing grain boundary scattering of phonons on the nanoscale. The thermoelectric properties of the consolidated FeSb2 emphasize the possibility of altering thermal transport of promising thermoelectric compounds by phonon scattering by engineering the interfaces at the nanoscale.
Extending the applicability of an open-ring trap to perform experiments with a single laser-cooled ion.
2015
An open-ring ion trap, also referred to as transparent trap was initially built up to perform $\beta$-$\nu$ correlation experiments with radioactive ions. This trap geometry is also well suited to perform experiments with laser-cooled ions, serving for the development of a new type of Penning trap, in the framework of the project TRAPSENSOR at the University of Granada. The goal of this project is to use a single $^{40}$Ca$^+$ ion as detector for single-ion mass spectrometry. Within this project and without any modification to the initial electrode configuration, it was possible to perform Doppler cooling on $^{40}$Ca$^+$ ions, starting from large clouds and reaching single ion sensitivity.…
Trapping of ions from high energy sources into a radiofrequency ion trap
1982
An attempt is described to confine ions, created externally and accelerated to some energy, in an rf quadrupole trap. 4 keV Ba+ ions were stopped on a Ni foil, placed in an aperture of one trap electrode. The Ba then was evaporated from the heated foil and ionized by electron impact. At background pressure of about 10−5 mbar of various light buffer gases (He, H2, N2), the trap was filled once with 105 ions, at a minimum primary ion number of 1010. The storage time was 10 min. From the data obtained the possibility of spectroseopic experiments on rare isotopes, created with accelerators or nuclear reactors, is discussed.
Graphene in strong laser field: experiment and theory
2015
The interaction of graphene nanoparticles and strong 64 fs pulses is examined. We demonstrate high-order harmonic generation in the plasma contained in crumpled sheets of graphene. The morphological studies of the debris of ablated graphene, application of single-color and two-color pumps of graphene-containing plasma, and theoretical consideration of the high-order harmonic generation in this medium are presented.
INTERPRETATION OF POTENTIAL INTERMITTENCE TITRATION TECHNIQUE EXPERIMENTS FOR VARIOUS Li-INTERCALATION ELECTRODES
2002
In this paper we compare two different approaches for the calculation of the enhancement factor Wi , based on its definition as the ratio of the chemical and the component diffusion coefficients for species in mixed-conduction electrodes, originated from the “dilute solution” or “lattice gas” models for the ion system. The former approach is only applicable for small changes of the ion concentration while the latter allows one to consider a broad range of intercalation levels. The component diffusion coefficient of lithium ions has been determined for a series of lithium intercalation anodes and cathodes. A new “enhancement factor” for the ion transport has been defined and its relations to…
In-situ small-angle x-ray scattering study of nanoparticles in the plasma plume induced by pulsed laser irradiation of metallic targets
2012
Import JabRef; International audience; Small angle x-ray scattering was used to probe in-situ the formation of nanoparticles in the plasma plume generated by pulsed laser irradiation of a titanium metal surface under atmospheric conditions. The size and morphology of the nanoparticles were characterized as function of laser irradiance. Two families of nanoparticles were identified with sizes on the order of 10 and 70 nm, respectively. These results were confirmed by ex-situ transmission electron microscopy experiments.
The effect of extracellular matrix proteins on the cellular response of HUVECS and HOBS after covalent immobilization onto titanium
2014
Biomimetic surface modifications are regarded as promising approach to stimulate cellular behavior at the interface of implant materials. Aim of the study was an evaluation of the cellular response of human umbilical cord cells (HUVECS) and human osteoblasts (HOBS) on titanium covalently coated with the extracellular matrix (ECM) proteins fibrinogen, collagen, laminin, and osteopontin. For the surface modification, titanium discs were first amino-functionalized by plasma polymerization of allylamine. The ECM protein conjugation was performed using the linker molecule α, ω-bis-N-hydroxysuccinimide polyethylene glycol (Di-NHS linker). For surface characterization, infrared spectroscopy and fl…