Materials Literature
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The dynamics of polymeric salt solutions are presented. The salt consists of chains $\rm A$ and $\rm B$, which are chemically different and interact with a Flory-interaction parameter $χ$, the $\rm A$ chain ends carry a positive charge whereas the $\rm B$ chain ends are modified by negative charges. The static structu…
Within the Kubo-Greenwood formalism we use the fully relativistic, spin-polarized, screened Korringa-Kohn-Rostoker method together with the coherent-potential approximation for layered systems to calculate the resistivity for the permalloy series Ni$_{c}$Fe$_{1-c}$. We are able to reproduce the variation of the resist…
In this paper we study reflection of holes in direct-band semiconductors from the linear potential barrier. It is shown that light-heavy hole transformation matrix is universal. It depends only on a dimensionless product of the light hole longitudinal momentum and the characteristic length determined by the slope of t…
Thin films of hydrogenated amorphous carbon (a-C:H) deposited by radio frequency plasma-enhanced chemical vapour deposition (rf-PECVD) have been studied for various applications. An interesting property of these films is their high breakdown strength (107 Vcm-1). This property of a-C:H can be exploited in high breakdo…
We propose a systematic, {\em a priori} approach to the problem of the calculation of solvation energies using continuum dielectric models coupled to quantum mechanical description of reacting molecules. Our method does not rely on empirically scaled van der Waals radii to create a dielectric cavity, but rather uses t…
Hydrogenated amorphous carbon (a-C:H), deposited by the rf-plasma enhanced chemical vapour deposition (rf-PECVD) technique, is a promising material for large area electronic and interlayer dielectric applications. The structural and electronic properties of rf-PECVD a-C:H, deposited at room temperature from CH4/He and…
Degassing of bundles of single-walled carbon nanotubes in vacuum at 500 K is found to drive the thermoelectricpower (TEP) strongly negative, indicating that the degassed metallic tubes in a bundle are n type. The magnitude of the negative TEP indicates that important asymmetry in the electronic carbon pi bands exists…
Dense, thick films of aligned single wall carbon nanotubes and nanotube ropes have been produced by filtration/deposition from suspension in strong magnetic fields. Electrical resistivity exhibits moderate anisotropy with respect to the alignment axis, while the thermopower is the same when measured parallel or perpen…
Zinc oxide, a wide-band-gap semiconductor with many technological applications, typically exhibits n-type conductivity. The cause of this conductivity has been widely debated. A first-principles investigation, based on density functional theory, produces strong evidence that hydrogen acts as a source of conductivity:…
We present a systematic trend study of the symmetric tilt grain boundaries about the <110> axis in molybdenum. Our results show that multiple structural phases, some incorporating vacancies, compete for the boundary ground state. We find that at low external stress vacancies prefer to bind to the boundaries in high co…
Synthetic methods for introduction of two substituents into the rings of octafluoroparacyclophane are presented. Nitration gives three isomers with nitro substituents on different rings: pseudo-ortho, pseudo-meta, and pseudo-para, in equal amounts. These dinitro compounds are shown to be precursors of a variety of oth…
Sandia National Laboratories (SNL) has produced limited quantities of fission-produced molybdenum-99 ( 99 Mo) within industry purity specifications using the Cintichem production process. Molybdenum-99 is produced by the irradiation of a target which has an electrochemically deposited layer of enriched uranium oxide.…
The adsorption of water on Nd 2 O 3 has been investigated by measuring the adsorption isotherm of water, water content, temperature-programmed desorption (TPD), and near-infrared (NIR) spectra and also by dielectric measurement. The water content of Nd 2 O 3 was found to be appreciably larger than that of typical meta…
We present new kinds of conducting gels of octylthiophene. Contrary to the gels previously obtained in our laboratory, they present two “high” gelation thresholds (i.e., related to high crosslink ratios). Consequently, systems close to the gelation threshold can be prepared with accuracy. Furthermore, they are calibra…
Two-dimensional arrays of Pd nanocrystals of varying diameters (1.8−6.0 nm) have been obtained after thiolization with alkane thiols of different chain lengths (C 4 −C 16 ). The stability and structure of these arrays have been explained in terms of the ratio of the particle diameter ( d ) and the alkane chain length…
Two liquid crystal diepoxides [1,4-phenylene bis(4-(2,3-epoxypropoxy)benzoate) ( A ) and 4,4‘-diglycidyloxydiphenyl ( B )] were cured with a diamine [4,4‘-diaminobiphenyl ( C )] in the nematic phase to obtain liquid crystalline thermoset (LCT) materials. The systems were studied using different curing conditions and d…
This is the first of a series of papers focusing on an experimental investigation of mechanisms contributing to the sequestration of hydrophobic organic compounds (HOCs) by macromolecular natural organic matter (NOM). It presents the results of a detailed study by differential scanning calorimetry (DSC) of NOM-related…
The electronic structure of the TiO 2 −SiO 2 interface has been investigated using X-ray absorption spectroscopy (XAS). TiO 2 overlayers have been grown on two substrates, amorphous SiO 2 and highly oriented pyrolytic graphite (for comparison), by evaporation of Ti in an oxygen atmosphere at room temperature. The evap…
A new prediction model for the autocatalytic random hydrolysis of aliphatic polyesters is proposed. The model predicts changes in the number- and weight-average degrees of polymerization. The model enables to avoid certain errors liable to occur in the estimation of hydrolysis with only the number-average molecular we…
The identification of a window of viscosities of poly(tetrafluoroethylene)s is described that permits standard melt-processing of this unique polymer into mechanically coherent, tough objects a polymer that, heretofore, has been characterized as “intractable” and “not melt-processable”.