Materials Literature
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Alzheimer's disease (AD) is characterized by the presence of amyloid-positive senile plaques and tau-positive neurofibrillary tangles. Aside from these two pathological hallmarks, a growing body of evidence indicates that the amount of oxidative alteration of vulnerable molecules such as proteins, DNA, and fatty acids…
Time-dependent density functionals in principle depend on the initial state of the system, but this is ignored in functional approximations presently in use. For one electron it is shown there is no initial-state dependence: for any density, only one initial state produces a well-behaved potential. For two non-interac…
Direct and unambiguous experimental evidence for the magnetic force density being of the form $M\nabla B$ in a certain geometry - rather than being the Kelvin force $M\nabla H$ - is provided for the first time. (M is the magnetization, H the field, and B the flux density.)
We show that nanostructure and resistivity of Pr0.5Ca0.5Mn0.98Cr0.02O3 are sensitive to whether the sample is zero-field-cooled (ZFC) of field-cooled (FC) either in the 'self magnetic field (H = 2 T)' of the electron microscope or under the external magnetic field of 2 T. FC resistivity at H = 2 T is lower than ZFC va…
The current efforts to fabricate non-volatile magnetic recording media with a high areal density is deteriorated by the increasing temporal instability of the stored information. If the stored energy per magnetic particle competes with the thermal energy, spontaneous magnetic reversal processes may occur. Deposition o…
We study the static and dynamic properties of bromine electrosorption onto single-crystal silver (100) electrodes by Monte Carlo simulation. At room temperature the system displays a second-order phase transition between a low-coverage disordered phase at more negative electrode potentials and a c(2x2) ordered phase w…
The hcp-fcc transformation induced in cobalt powder by ball milling at room temperature was studied using the excess Gibbs free energy for the metals, in nanometric form, to calculate the activation energy that the atoms need for the phase transformation to occur. The crystalline component of the nanocrystalline cobal…
Constitutive equations are derived for the viscoelastic response of rubbery polymers at finite strains. A polymer is thought of as a network of long chains connected to temporary junctions. At a random time, a chain detaches from a junction, which is treated at transition from its active state to the dangling state. A…
When two or more atoms bind to a solid surface, the substrate can mediate an interaction between them. In this paper, we use density-functional theory to quantify the substrate-mediated pair interaction between two adatoms on a compressively strained Ag(111) surface and on unstrained Ag(111). On the strained surface,…
Partially deacetylated chitins with different degrees of deacetylation (DD) were prepared by alkaline treatment under homogeneous conditions, and the effect of DD on their solubility was discussed in terms of crystal structure and mode of hydrogen bonding. With an increase in the treatment time, the DD of chitin incre…
The hydrogenation of acetylene and ethylene was studied on Au/Al 2 O 3 catalyst. Acetylene and hydrogen reacted readily to produce ethylene, but not to ethane on the catalyst in the temperature range between 313 and 523 K. The hydrogenation of ethylene on the catalyst occurred only at much higher temperatures over 573…
Single crystals of phenanthrene were successfully grown from melt using Bridgeman Crystal Growth System Type 365. The starting material was purified by sublimation and zone refining techniques in specially designed crystal growth tubes. Phenanthrene single crystals grow with the plane of maximum growth corresponding t…
Glasses were prepared from the system xLa<SUB>2</SUB>O<SUB>3</SUB>(DOT)(1-x)P<SUB>2</SUB>O<SUB>5</SUB>, where 0.00 <EQ x <EQ 0.30 (mole fraction), and densities, refractive indices and glass transition temperatures were determined. Inflections in the property/composition trends were observed at x approximately 0…
Rates of dehydroxylation of two Nd-doped metaphosphate laser glasses (LG-770 and LHG-8) are measured and modeled. Glass melts ranging in size from 100 g to 2.8 kg were bubbled with O<SUB>2</SUB> containing various H<SUB>2</SUB>O partial pressures (P<SUB>H(subscript 2</SUB>O)) and with O<SUB>2</SUB>/Cl<SUB>2</SUB> mixt…
Phosphate glasses containing metallic copper nanoparticles were prepared by melt-quenching and post heat treatment method. The average size, size-distribution, concentration, and dispersion of metallic copper nanoparticles in phosphate glasses were investigated by using both spectrophotometer and transmission electron…
Conditions for preparing samples of Yb<SUP>3+</SUP>-doped fluoroaluminate glasses of high optical quality ((Delta) n <EQ 2 X 10<SUP>-6</SUP>), their structure, and optical properties have been studied while varying the phosphate (5 to 40 mol%) and the Yb<SUP>3+</SUP> content (5 to 12 X 10<SUP>20</SUP> ions/cm<SUP>3</S…
The optical and mechanical properties of polycrystalline MgAl<SUB>2</SUB>O<SUB>4</SUB> spinel make this material of interest for transparent armor and for window and dome applications in the 0.3 micrometers to 5.5 micrometers range. Spinel was briefly produced commercially, and qualified for a range of dome and window…
Linear α,ω-vinyl-terminated poly(diethylsiloxane) (PDES) chains were synthesized and fractionated to obtain melts of low polydispersity. The fractionated samples were characterized using gel permeation chromatography and dilute solution viscometry. PDES elastomers were also prepared from the melts using hydrosilylatio…
Polyethers having well-defined comb-shaped architectures were prepared by using poly(4-hydroxystyrene) (PHSt) as a multifunctional initiator for graft polymerization of either ethylene oxide (EO) or a mixture of EO and propylene oxide (PO). The grafting process was performed in 1,4-dioxane using NaH as ionizer for the…
The field of molecule-based magnets is a relatively new branch of chemistry, which involves the design and study of molecular compounds that exhibit a spontaneous magnetic ordering below a critical temperature, Tc. One major goal involves the design of materials with tuneable Tc's for specific applications in memory s…