Materials Literature
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We investigated the order−order and order−disorder transitions in a solution consisting of polystyrene- block -polyisoprene- block -polystyrene copolymer (Vector 4111 having weight-average molecular weights of 26 × 10 3 and 117 × 10 3 for polystyrene and polyisoprene block chains, respectively) and dioctyl phthalate (…
The shape and optical properties of Au nanoparticles electrochemically deposited within the pores of porous alumina membranes have been studied as a function of the temperature to which the Au/alumina composite was heated. Low aspect ratio Au nanoparticles begin as thin skinned particles, essentially flakes of Au with…
We review the mechanism of integrated circuit failure known as “electromigration.” Electromigration is a physical wearout process that operates primarily in the on-chip interconnections of an integrated circuit. It is caused by the currents that run through those interconnections. The first part of the review introduc…
A Knudsen cell mass spectrometric technique was used to study both the neutral and charged species that are in equilibrium in saturated vapor over lutetium trichloride. It was found that in the temperature range between between 885 and 1100 K the vapor is comprised of molecular (LuCl3), and ionic Cl−(LuCl3)n clusters…
Deuterium solid-state quadrupole-echo NMR techniques were used to probe the dynamics of bulk and silica-adsorbed methyl-labeled poly(methyl acrylate)- d 3 (PMA- d 3 ). For bulk PMA- d 3, collapse of the 2 H NMR powder pattern indicated a sudden increase in segmental motion at about 50 °C. This temperature was 40 °C ab…
The formalism for tetraatomic reactive scattering using row-orthonormal hyperspherical coordinates is presented. The transformation properties of these coordinates under kinematic rotations and symmetry operations are derived, as are the corresponding Hamiltonian and volume element. Each of the nine operators which co…
The sdh operon of Sulfolobus acidocaldarius DSM 639 is composed of four genes coding for the 63.1-kDa flavoprotein (SdhA), the 36.5-kDa iron-sulfur protein (SdhB), and the 32.1-kDa SdhC and 14.1-kDa SdhD subunits. The four structural genes of the sdhABCD operon are transcribed into one polycistronic mRNA of 4.2 kb, an…
A series of luminescent tetranuclear copper(I) and silver(I) chalcogenide complexes have been synthesized and characterized. The photophysical and photochemical properties of these complexes have also been investigated. The long-lived excited state of these luminescent clusters is believed to bear a high parentage of…
Abstract The size of glass transition cooperativity for 11 polymers and glycerol is determined from heat capacity spectroscopy (HCS) and differential scanning calorimetry (DSC) by using a calorimetric fluctuation formula. The data cover in total the 0.25 ≤ x ≤ 0.95 part of the reduced temperature interval between the…
Ligands 5 and 8, derived from the coupling of [3,5-bis[(diphenylphosphinyl)methyl]phenyl]oxy groups to bi- and trifunctional spacers, respectively, were cyclometalated with Pd[CH 3 CN] 4 (BF 4 ) 2, cis- [PtCl 2 (PPh 3 ) 2 ], or NiCl 2 ·6H 2 O. The cationic Pd and Pt complexes were converted into overall neutral Pd−Cl…
We propose a method based on high-resolution electron-energy-loss spectroscopy to measure in situ the neutral fragmentation products arising from the impact of low energy electrons on thin solid films at low temperature. We show more particularly that the detection of electronic states from a dissociation product is a…
The topography of water-soluble polymer chains immobilized on a rigid polymer surface underwater was studied using atomic force microscopy (AFM). As the substrate polymer a smooth poly(ethylene terephthalate) (PET) film was employed and polymer chains of various lengths were chemically immobilized by surface graft pol…
The constitutive response and failure behavior of a W-Ni-Fe alloy over the strain rate range of 10-4 to 5 X 105 s-1 is experimentally investigated. Experiments conducted are pressure-shear plate impact, torsional Kolsky bar, and quasi-static torsion. The material has a microstructure of hard tungsten grains embedded i…
A new microporous sol-pillared clay was prepared by the ion-exchange of the interlayer Na + ions of montmorillonite with SiO 2 −Fe 2 O 3 mixed oxide sol particles. The mixed oxide sol solution was prepared by titrating an Fe 3+ aqueous solution with NaOH in the presence of silica sol particles. Upon pillaring with the…
Polymerization and segregation behavior of n -decyl acrylate in a smectic liquid crystal were characterized. The polymerization rate increased dramatically as the temperature was decreased and the order of the liquid crystalline media increased. To ascertain the kinetic mechanisms behind this behavior, the kinetic con…
We have observed the surface-pressure driven flow of an arachidic (eicosanoic) acid Langmuir monolayer through a narrow channel using Brewster angle microscopy. By following distinctive features of the monolayer domain morphology we determined the velocity profile across the channel for various values of surface press…
Experimental results concerning end-linked poly(dimethylsiloxane) pregel clusters quenched at different distances from the gelation threshold are reported. Static and quasielastic light scattering experiments and intrinsic viscosity measurements allow us to verify that static properties of this chemical system are pro…
Abstract Hydrolytically stable phosphorus‐containing monomers, such as 4,4′‐bis(fluorophenyl)methylphosphine oxide (BFPMPO), 4,4′‐bis(hydroxyphenyl)methylphosphine oxide (BOHPMPO), and 4,4‐bis(hydroxyphenyl)phenylphosphine oxide (BOHPPO), were synthesized and used in nucleophilic aromatic substitution poly‐condensatio…
Micro- and nanocrystalline systems exhibit properties that differ markedly from bulk systems. Diamond, a prototypical system, demonstrates a broadening, shift, and emergence of Raman phonon modes that are believed to originate from finite-size effects. Such information should be useful in constraining confinement mode…
SiO 2 /Ge nanocrystal/SiO2 structures have been fabricated by deposition of Ge film on a SiO2 layer and subsequent oxidation of the structure at a temperature between 800 °C and 1000 °C. Secondary ion mass spectrometry results indicate that the Ge precipitates into the bulk SiO2 at a density of 1×1012 cm−2. Raman spec…