Materials Literature
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The shikimate pathway synthesizes aromatic amino acids and other essential metabolites that are necessary for bacteria, plants and fungi to survive. This pathway is not present in vertebrates and therefore represents an attractive target for antibacterial agents. We have successfully crystallized and solved the struct…
Scanning tunnelling microscopy (STM) and current imaging tunnelling current spectroscopy (CITS) methods were performed on polycrystalline diamond films grown on silicon substrates grown by microwave plasma-enhanced chemical vapour deposition. Large tunnelling currents were observed at some grain boundaries and crystal…
We have investigated the dynamics of phenylene rings in a glassy polysulfone (bisphenol-A-polysulfone) by means of quasielastic neutron scattering. Nowadays it is well known that these molecular motions are directly connected with the mechanical properties of engineering thermoplastics in general. The particular syste…
We investigate ring formation of single-walled carbon nanotubes theoretically in this paper. The conformation energy of the nanotubes is identified as the curvature elastic energy of a curved graphite and the intertube van der Waals interaction. The entropy of ring nanotubes depends on the total number of carbon atoms…
Stress induced voiding (SIV) is explored from the aspects of design attribute and geometry parameters. Two kinds of test structures were used to evaluate resistance change in relation to reliability and to understand the SIV mechanism. Thus, a reliability-robustness guideline from a consideration of geometry configura…
Results from a molecular dynamics simulation of a melt of unentangled polymers are presented. The translational motion, the large-scale and the local reorientation processes of the chains, as well as their relations with the so-called "normal" and "segmental" dielectric relaxation modes are thoroughly investigated in…
Time-dependent dielectric breakdown (TDDB) of sub-half-micron Cu interconnects was investigated with regard to the waiting time between Cu-CMP and barrier dielectric deposition. Breakdown voltage and TDDB lifetime between adjacent Cu wires deteriorated abruptly as the waiting time in air passed 4 days. This is due to…
Abstract The adsorption of several chitosan samples with different degrees of deacetylation (65, 73, 85, and 92%) and their interactions with the main components of reed pulp suspensions were investigated with gel permeation chromatography, phenol/sulfuric acid spectrophotometry, microelctrophoresis, and retention/dra…
It is increasingly realised that the status of measuring the thermal properties of thermal interface materials (TIMs) and the proliferation of these data cause much irritation to vendors and users alike. This paper discusses the various problems underlying the status quo and offers a strategy to overcome the problems…
Molecular dynamics computer simulations are used to determine the self-diffusion coefficients for a Gay-Berne model mesogen GB (4.4,20,1,1) in the isotropic, nematic and smectic A phases along two isobars. The values of the parallel and perpendicular diffusion coefficients, D(parallel) and D(perpendicular), are calcul…
In this work the study of the dynamics of the segmental motions close to T g of a poly(methyl methacrylate), PMMA , network was analysed by distinct mechanical spectroscopy techniques. Three techniques were employed: dynamic mechanical analysis (DMA), creep and thermally stimulated recovery (TSR). The time–temperature…
The device and circuit implications of carbon nanotube field effect transistors (CNFET) as a logic technology are assessed. The salient device characteristics and fabrication techniques are described based on measured device parameters. The device/circuit performance of CNFET are estimated and the key technical challe…
Abstract The reinforcement mechanics of viscose‐fiber‐reinforced polypropylene (PP) composites were studied. The effect of the coupling agent, maleated polypropylene (MAPP), was of special interest. The fibers, coupling agent, and PP were extruded and injection‐molded. The composition, mechanical properties, fracture…
We present a discrete solvent reaction field (DRF) model for the calculation of frequency-dependent hyperpolarizabilities of molecules in solution. In this model the solute is described using density functional theory (DFT) and the discrete solvent molecules are described with a classical polarizable model. The first…
We have synthesized ZnCNi 3 in which Zn replaces Mg of the superconducting intermetallic perovskite MgCNi 3 ( K). Dc-resistivity and magnetic measurements show that ZnCNi 3 is a paramagnetic metal without onset of superconductivity down to 2 K. Furthermore, even though the two compounds have the same lattice structure…
A new approach for obtaining an estimate of the effective size of the free neutral clusters is proposed. The approach relies on an experimental measure of the surface and interior or "bulk" cluster atoms provided by the x-ray photoelectron spectroscopy and on a model for the attenuation of photoelectrons ejected from…
We study the thermodynamics and single-chain statistics of wormlike polymer solutions with Maier–Saupe-type interactions using self-consistent-field (SCF) theory. The SCF equations are derived using a systematic field-theoretical approach which yields the SCF equations as the lowest order approximation, but permits fl…
Abstract An experimental study of the peroxide‐induced degradation of polypropylene in a corotating twin‐screw extruder, operating under various conditions, was reported. Runs were performed without and with peroxide in different concentrations. The evolution of the chemical reactions along the extruder was characteri…
Polycrystalline samples of titanium oxide were prepared by thermal sintering, in argon and air atmospheres at temperatures ranging from 1100 to 1500 °C, from powders of anatase and rutile phases. The samples sintered in argon were further treated in oxygen at the temperature of 800 °C for intervals of time up to 8 h.…
With the increase of impact velocity, penetration mechanism may change at a transition point from nondeformable projectile penetration regime to semihydrodynamic penetration regime. Analysis is presented to predict this transition point. Good agreements between analytical predictions and experimental results are obtai…