Materials Literature
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Strong, tough, and almost fully dense BN/SiC‐coated Hi‐Nicalon‐fiber‐reinforced celsian‐matrix composites have been fabricated by impregnation of the fiber tows with the matrix slurry, winding on a drum, stacking the prepreg tapes in the desired orientation, and hot pressing. The monoclinic celsian phase in the matrix…
Phase transitions in solid solutions of strontium titanate with titanates of the divalent metals Pb, Ba, and Ca are considered. It is shown that the critical concentration x c in the well-known expression relating the transition temperature to the polar state in SrTiO 3 with the concentration x of divalent metals, T c…
The solution conformation of a peptide LYS(11-36), which corresponds to the beta-sheet region in T4 lysozyme, has been examined in aqueous solution, TFE, and SDS micelles by CD and 1H NMR spectroscopy. Secondary structure predictions suggest some beta-sheet and turn character in aqueous solution but predict a helical…
A chlorine precursor copolymer was synthesized from the monomers 1,4-bis(chloromethyl)-2,5-(dihexyloxy)benzene and the metal complexes [5,15-bis(mesityl)-10,20-bis(4-(chloromethyl)phenyl)porphyrin] in different ratios with potassium tert -butoxide. The precursor copolymers were readily soluble in common organic solven…
The tensile creep behavior of an (Al 2 O 3 ‐SiC) nanocomposite that contains 5 vol% of 0.15 μm SiC particles is examined in air under constant‐load conditions. For a stress level of 100 MPa and in the temperature range of 1200°–1300°C, the SiC reduces the creep rate of Al2O3 by 2–3 orders of magnitude. In contrast to…
This paper gives basic information pertaining to the plasma treatment of wool top considered as an industrially feasible process. The results presented here are based on experience gained over five years with the world's first prototype machine for continuous treatment of wool tops with glow discharges. The machine ca…
The assignments of Raman bands in the spectra of silicate and germanate glasses, including SiO2, GeO2, Rb2Si4O9, NaFe3+Si3O8, anhydrous and hydrous albite (NaAlSi3O8) and anhydrous and deuterated Ge-albite (NaAlGe3O8) and Ge-jadeite (NaAlGe2O6), were re-examined in the light of new information from Raman measurements…
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…