Search results for "Interfaces."
showing 10 items of 1252 documents
3D photonic crystal intermediate reflector for micromorph thin-film tandem solar cell
2008
The concept of 3D photonic intermediate reflectors for micromorph silicon tandem solar cells has been investigated. In thin-film silicon tandem solar cells consisting of amorphous and microcrystalline silicon with two junctions of a-Si/μc-Si, efficiency enhancements can be achieved by increasing the current density in the a-Si top cell. It is one goal to provide an optimized current matching at high current densities. For an ideal photon-management between top and bottom cell, a spectrally selective intermediate reflective layer (IRL) is necessary, which is less dependent of the angle of incidence than state-of-the-art thickness dependent massive interlayers. The design, preparation and cha…
Assessment and inter-comparison of recently developed/reprocessed microwave satellite soil moisture products using ISMN ground-based measurements
2019
Soil moisture (SM) is a key state variable in understanding the climate system through its control on the land surface energy, water budget partitioning, and the carbon cycle. Monitoring SM at regional scale has become possible thanks to microwave remote sensing. In the past two decades, several satellites were launched carrying on board either radiometer (passive) or radar (active) or both sensors in different frequency bands with various spatial and temporal resolutions. Soil moisture algorithms are in rapid development and their improvements/revisions are ongoing. The latest SM retrieval products and versions of products that have been recently released are not yet, to our knowledge, com…
Energetics of Water−Dodecyl Surfactant−Macrocyclic Compound Ternary Systems
1996
Enthalpies of dilution and osmotic coefficients of sodium dodecyl sulfate (NaDS) and dodecyltrimethylammonium bromide (DTAB) in water + 18-crown-6 ether (CR) and water + β-cyclodextrin (CD) at a fixed cosolvent concentration were measured at 298 and 310 K, respectively, as functions of the surfactant concentration (mS). Enthalpies of transfer ΔH (W → W + S) of CR (0.03 m) from water to NaDS and DTAB aqueous solutions as functions of mS were also determined at 298 K. From the enthalpies of dilution the apparent (LΦ,S) and partial (L2,S) molar relative enthalpies of both surfactants were calculated. Despite CR forms inclusion complexes with the anionic surfactant only, the L2,S vs mS profiles…
A remark on hyperplane sections of rational normal scrolls
2017
We present algebraic and geometric arguments that give a complete classification of the rational normal scrolls that are hyperplane section of a given rational normal scrolls.
Optimizing the Binding Energy of the Surfactant to Iron Oxide Yields Truly Monodisperse Nanoparticles.
2018
Despite the great progress in the synthesis of iron oxide nanoparticles (NPs) using a thermal decomposition method, the production of NPs with low polydispersity index is still challenging. In a thermal decomposition synthesis, oleic acid (OAC) and oleylamine (OAM) are used as surfactants. The surfactants bind to the growth species, thereby controlling the reaction kinetics and hence playing a critical role in the final size and size distribution of the NPs. Finding an optimum molar ratio between the surfactants oleic OAC/OAM is therefore crucial. A systematic experimental and theoretical study, however, on the role of the surfactant ratio is still missing. Here, we present a detailed exper…
Adsorption of m-Xylene on Prehydrated Zeolite BaX: Correlation between Temperature-Programmed Desorption and Low-Temperature Neutron Powder Diffract…
1999
Adsorption of m-xylene on partially hydrated zeolite BaX is studied by thermogravimetry, mass spectrometry, temperature-programmed desorption and neutron diffraction for different m-xylene loadings of the zeolite. Macroscopic and microscopic measurements, for both molecules, were correlated and relationships were found between the crystallographic positions of the adsorbed molecules on the zeolite and macroscopic properties such as the number and the area of the peaks in the desorption spectra for m-xylene or water. The influence of water molecules on the adsorption phenomenon of m-xylene on BaX zeolite was characterized. In particular, it was shown that the increase of the filling of the p…
Determination of cluster binding energies on metal surfaces by statistics
2000
Abstract Two simple formulae to determine binding energies of two-dimensional clusters on surfaces in thermal equilibrium are derived. One requires measurement of monomer and cluster populations and of the surface temperature. The cluster dissociation rate is derived and related to the atom hopping rate, allowing the theory to be extended to adatom populations that are not in chemical equilibrium. The result gives a recipe for determining dissociation energies that requires measurements of only two rates at a single temperature.
Influence of titanium-vanadium alloys on cell morphology: electron microscopy and ESCA studies
2000
Titanium and its alloys provide optimum metallurgical properties for implants. The formation of an oxide layer favours compatibility with the adjacent hard and soft tissues. Research focuses on further optimizing the passive layer, particularly with respect to minimizing metal ion migration into the tissues. The present study concentrates on two alloys (Ti6A14V and Til.5A125V) coated with oxide layers generated by different techniques: thermal oxidation, anodic oxidation and sol-gel treatment. Only thermal oxidation fails to reduce surface and subsurface concentrations of vanadium, whereas other treatments avoid the element in the outermost surface areas of the alloys. Additionally, the the…
Surface modification of luminescent lanthanide phosphate nanorods with cationic "Quat-primer" polymers.
2011
"Quat-primer" polymers bearing cationic groups were investigated as a surface modifier for Tb-doped cerium phosphate green-emitting fluorescent nanorods (NRs). The NRs were synthesized by a microwave process without using any complex agents or ligands and were characterized with different analytical tools such as X-ray diffraction, transmission electron microscopy, and fluorescence spectroscopy. Poly(ethyleneimine) partially quarternized with glycidyltrimethylammonium chloride was synthesized separately and characterized in detail. (1)H and (13)C NMR spectroscopic studies revealed that the quaternary ammonium group was covalently attached to the polymer. UV-vis spectroscopy was used to exam…
Simulation of abrasion–corrosion at high temperatures by in situ pulsed laser spallation of oxide films
1999
Abstract A pulsed Nd:YAG laser combined with a thermogravimetric cell has been used to spall in situ the oxide films grown on a Fe–2.25Cr–1Mo steel at high temperature in oxidizing media. This technique allows to define the oxidation rate of bare metal surfaces, which can be used to simulate the corrosion-dominated regime during slurry–erosion tests.