Materials Literature
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With the use of high-resolution transmission electron microscopy the structure and morphology of montmorillonite (MMT), a material of current interest for use in polymer nanocomposites, was characterized. Using both imaging theory and experiment, the procedures needed to generate lattice images from MMT were establish…
We examine the structure and properties of cold drawn Ti-50.1 at % Ni and Ti-50.9 at % Ni shape memory alloy wires. Wires with both compositions possess a strong <111> fiber texture in the wire drawing direction, a grain size on the order of micrometers, and a high dislocation density. The more Ni rich wires contain f…
The first successful preparation of nanofibers of a polyampholyte (N-carboxyethylchitosan) by electrospinning was achieved by adding a non-ionogenic water-soluble polymer to the spinning solution. Using this approach, other polyelectrolytes, poly(2-acryloylamido-2-methylpropanesulphonic acid) (PAMPS), and copolymers o…
We used a resonant ultrasound spectroscopy technique to measure the nine independent elastic constants of cyclotrimethylene trinitramine C3H6N6O6 also known by its code designation RDX. The measurements were made on a single crystal grown from acetone containing RDX in solution. The elastic constants in gigapascal uni…
Ex situ transmission electron microscopy (TEM) was used to study the crystal morphology in sputtered amorphous Ge4Sb1Te5, Ge2Sb2Te5, and Ag0.055In0.065Sb0.59Te0.29 thin films used for phase change recording. Tilting of plan view samples revealed that each crystallized growth formation is a bent single crystal. Cross-s…
High-yield multiwalled boron nitride (BN) nanotubes have been produced using a ball milling−annealing method. The BN nanotubes with a diameter less than 10 nm and a well-crystallized multiwalled structure were formed via an in situ nitriding reaction. The systematic investigation of the formation process at different…
The selection of the optimum fluoroelastomer, from the vast range available, for a high temperature or chemically aggressive application is often hampered by insufficient data on the thermal stability of the materials, especially under transient conditions. This feature describes the use of strain energy density to as…
Surfactant templated mesoporous silica thin films were prepared as the intermetal dielectric for ultralarge scaled integrated circuit application, and the thermal and chemical stability of the Cu∕nitridedTa∕mesoporous silica film stack on the Si wafer was studied. Trimethylsilylation of the mesoporous silica thin film…
Ab initio calculations suggest the possibility of forming boric acid clusters in the laboratory. The most stable form of the boric acid dimer contains two hydrogen bonds, similar to the carboxylic acid dimers. Though the trimer and the tetramer form extensions of this geometry, the pentamer prefers a bowl shape. Any a…
Neste artigo é apresentado o mundo dos cristais líquidos: o que são e como são caracterizadas as mesofases líquido-cristalinas e suas aplicações. Abordam-se as teorias fenomenológicas existentes na literatura para descrever o meio líquido-cristalino, bem como os efeitos de superfícies de contorno. Além disso, é mostra…
The hypoglycaemic drug metformin is derived from galegine, which is found naturally in Goat’s rue (gallega officinalis). This plant is speading northwards in the UK.
Titanium alloys are widely used in various industrial, domestic, and medical applications such as turbine blades, bicycle frames, knee implants, etc. The two-phase titanium alloy Ti-6Al-4V (wt. percent) is considered to be a workhorse alloy for many applications in these diverse fields. Despite the large body of work…
The thickness of a skin layer on the parts made by a microcellular injection moulding process may influence its properties, including impact and tensile strength, density and sound transmission. Therefore it is necessary to study the variations in skin layer thickness with processing parameters. In this paper, the inf…
A short review of liquid crystal compounds with a low birefringence and ordinary refractive index is presented. Special attention is given to alkylcyclohexylalkyl carbonates, which belong to a family of LCs having high clearing point temperatures, low viscosity, and no as low as 1.442. Examples of multicomponent mixtu…
The frequency dependent dielectric properties of Ni 1 - x Cd x Cr x Fe 2 - x O 4 (x = 0.0, 0.3, 0.5, 0.7 and 1.0) spinel ferrite system are studied by measuring dielectric constant (e'), dielectric loss (D) and conductivity (σ a , c ) at 300 K in the frequency range 100 Hz-2 MHz. The highest value of σ a . c and e' is…
Transient safety characteristics of accelerator-driven systems using advanced minor actinide fuels have been investigated. Results for a molybdenum-based Ceramic-Metal (CerMet) fuel, a magnesia-based Ceramic-Ceramic fuel, and a zirconium-nitride–based fuel are reported. The focus is on the inherent safety aspects of c…
Polycrystalline samples of Pb 3 R 3 Ti 5 Nb 5 O 30 (R = La and Sm) have been synthesized by a high-temperature solid-state reaction technique. X-ray diffraction (XRD) analysis of the compounds showed the formation of single phase compounds in an orthorhombic crystal structure. Studies of dielectric constant (ϵ) of the…
The algological investigations in the protected landscape areas have started at the end of the 19th century. As a result of the intensive floristical and taxonomic research a large number of records were accumulated over a period of last century, which were summarised in a monograph (Németh 2004). In the book mentione…
Transmittance characteristic in a homogeneously aligned liquid crystal (LC) cell driven by a fringe-electric field is investigated as a function of cell gap using the LC with positive dielectric anisotropy. In this device, the fringe-electric field drives the LCs to rotate so that the dielectric torque is electrode-po…
Self-assembly of nanoporous silica shapes is of great interest for modern nanotechnology because of uniform pore size, simplicity, and low cost of production. However, there are two major problems that prevent broad use of the self-assembly process. First, the process brings too broad a variety of the assembled shapes…