Materials Literature
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Native cellulose has been oriented in an ac electric field at both the macroscopic and colloidal level. Ramie fiber fragments suspended in chloroform have been shown to point along the field. Cellulose microcrystal suspensions in cyclohexane have also been allowed to evaporate in an electric field and have exhibited a…
We present a systematic experimental investigation of the reactions between hydrogen plasma and single-walled carbon nanotubes (SWNTs) at various temperatures. Microscopy, infrared (IR) and Raman spectroscopy, and electrical transport measurements are carried out to investigate the properties of SWNTs after hydrogenat…
We consider the formation and stability of the vibronic polaron arising in a degenerate or nearly degenerate electronic system coupled to an appropriate vibrational mode. We define the electron-phonon coupling as a mixing of the electronic states by the phonon mode. Our investigation is similar to that carried out rec…
Neutron radiography in many cases is the only non-destructive technique available for the analysis of a wide range of samples from metallurgy, materials engineering and materials testing. In this paper the potential of the technique is illustrated for a transient liquid phase (TLP) joint. TLP bonding produces interfac…
A class of proposed coherent precipitate structures (Guinier-Preston zones) in the Al-Mg-Si alloy are investigated using first-principles density functional theory methods. The cluster expansion method is used to extract effective interaction parameters, providing the means for large scale energy calculations of alloy…
This paper contains results of investigations of inhomogeneous states caused by the coexistence of ferroelectric and antiferroelectric phases in lead-zirconate-titanate based solid solutions. The domains of ferroelectric and antiferroelectric phases with sizes of the order of 20 to 30 nm coexist in the bulk of the sam…
Magneto-impedance (MI) of soft ferromagnetic materials is a sensitive function of the amplitude and frequency of exciting a.c magnetic field. MI (Z) of amorphous ferromagnetic ribbon of nominal composition Fe73.5Nb3 Cu1 Si13.5 B9 is measured at different excitation currents with frequency ranging from 30kHz to 120KHz…
We report a systematic study of the wetting of cylindrical alumina nanopores with polystyrene melts. A transition from partial to complete wetting was observed with increasing annealing temperature, resulting in the formation of very different one-dimensional polymeric nanostructures (nanorods and nanotubes) within cy…
Structural distortions in post-transition metal oxides are often explained in terms of the influence of sp hybrid "lone pairs." Evidence is presented here showing that this model must be revised. The electronic structures of prototypically distorted alpha-PbO and alpha-Bi2O3 have been measured by high-resolution x-ray…
Nanoparticles consisting of either a solid core of GdF 3 or an 80/20 mixture of GdF 3 and LaF 3 have been prepared for use as NMR and MRI relaxation agents. To obtain high aqueous solubilities, the particles were coated with either citrate ( cit ) groups (in the case of GdF 3 nanoparticles), giving the nanoparticle a…
Four molecules that have been proven to act as corrosion inhibitors of mild steel in acidic media are studied. The inhibitive efficiency of these molecules is explained by means of electronic structure calculations of the protonated species that seem to represent better the actual situation of the experimental conditi…
We present a simple method for fabricating superhydrophobic silicon surfaces. The method consists of irradiating silicon wafers with femtosecond laser pulses and then coating the surfaces with a layer of fluoroalkylsilane molecules. The laser irradiation creates a surface morphology that exhibits structure on the micr…
The application of variational density functional perturbation theory (DFPT) to lattice dynamics and dielectric properties is discussed within the plane-wave pseudopotential formalism. We derive a method to calculate the linear response of the exchange-correlation potential in the GGA at arbitrary wavevector. We intro…
Abstract Summary: Linear polymeric core, polyethylenimine (PEI), is successfully dendronized divergently using different‐generation polyamidoamine (PAMAM)‐type dendrons. The formed dendronized polymers are further end‐capped using long alkyl acrylate, hexyl acrylate, to give macromolecular amphiphiles, which perform a…
${\mathrm{Ba}}_{0.5}{\mathrm{Sr}}_{1.5}{\mathrm{Zn}}_{2}{\mathrm{Fe}}_{12}{\mathrm{O}}_{22}$ is a promising multiferroic compound in which the electric polarization is intimately connected to the magnetic state. In principle, ferroelectrity might exist above the room temperature, but the electrical conductivity that i…
Colloidal dispersions of Laponite platelets are known to age slowly from viscous sols to colloidal glasses. We follow this aging process by monitoring the diffusion of probe particles embedded in the sample via dynamic light scattering. Our results show that the time-dependent diffusion of the probe particles scales w…
Abstract Summary: Evidence of clay migration from the core to the surface of poly(propylene)/montmorillonite nanocomposites is provided. A three‐ to fivefold increase in the clay concentration of the surface is obtained during isothermal heating in oxidative atmosphere. The mechanism of migration is investigated by me…
Abstract For economic reasons, reaction rate and energy efficiency of ultrasonic devices need to be higher. In this investigation, it was found that the 850 kHz ultrasonic device achieves a higher energy efficiency and a higher sonochemical reaction rate than the 24 or 30 kHz device during the oxidation of KI or the d…
Abstract Transparent superhydrophobic surfaces were prepared by self‐assembly of hydrophobic n‐octa‐ decyltrimethoxysilane (H 3 C(CH 2 ) 17 Si(OCH 3 ) 3 , ODS) and (3,3,3‐trifluoropropyl)trimethoxysilane (F 3 C(CH 2 ) 2 Si(OCH 3 ) 3 , FAS3) monolayers from gas phase on transparent nanoporous alumina surfaces. Water co…
Abstract Summary: Chain‐growth polycondensations of 3‐aminobenzoic acid methyl esters 1a and 1b , bearing a tri‐ or tetra(ethylene glycol) methyl ether unit on the amino group, respectively, were carried out with lithium hexamethyldisilazide (LiHMDS) as a base and phenyl 4‐methylbenzoate ( 2 ) as an initiator in THF a…