Materials Literature
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We present experimental evidence that during rapid deformation of at least some crystalline and polymeric solids heat is generated at unexpectedly high temperatures beginning essentially at the moment deformation begins. The heat was observed by fast infrared sensors. Both the initial infrared emissions and the appare…
The microscopic ``spin-gas'' model reproduces and physically explains the sequence of liquid-crystal phases, nematic--smectic-${A}_{d}$--nematic--smectic-${A}_{d}$ --nematic--smectic-${A}_{1}$, which was observed with decreasing temperature in recent experiments. The microscopic frustration inherent to smectic structu…
High-purity (99·999%) and fully annealed copper specimens have been irradiated in the DR-3 reactor at Ris⊘ to doses of 1 × 1022 and 5 × 1022 neutrons (fast)m−2 (2 × 10−3 dpa and 1 × 10−2 dpa, respectively); the irradiation experiments were carried out at 250°C. The irradiated specimens were examined by transmission el…
The onchip power distribution problem for highly scaled technologies is investigated. Metal migration and line resistance problems as well as ways to optimize multilayer metal technology for low resistance, low current density, and maximum wirability are also investigated. Fundamental lower limits and the limiting fac…
The nrdB gene, which encodes the B2 subunit of Escherichia coli ribonucleotide reductase (EC 1.17.4.1), was cloned into multicopy plasmid pSPS2. This vector, which contains the pL promoter of bacteriophage lambda and the tetracycline resistance gene of pBR322, was transformed into a lysogenic host with a thermolabile…
Interactions between silicon nitride particles and hydroxide precipitates were investigated using electrophoresis measurements. Conditions under which stable suspensions of silicon nitride particles and flocculation and heteroflocculation of silicon nitride/hydroxide mixtures occur were Identified. On the basis of the…
Abstract If protein single crystals larger than those suitable for x‐ray analysis are obtained, various spectroscopic, thermal, mechanical, and electrical measurements become possible. To understand the factors governing the crystal size, tetragonal lysozyme crystals were grown in batches at 15°C from solutions of dif…
Abstract Upon shearing, some polymeric liquid crystals develop a particular texture, called “band texture,” consisting of fine equidistant black lines as viewed between crossed polarizers. In mesomorphic hydroxypropylcellulose–water solutions, these bands are due to relaxation of the shear. The band texture appears af…
By means of constant-temperature, constant-pressure molecular dynamics techniques, we simulate the melting and crystallization processes of a model system composed of 864 Lennard-Jones (LJ) particles under periodic boundary conditions. On heating an fcc crystal of LJ particles, it is ascertained that melting takes pla…
Abstract The study of infrared reflection spectra of SbSBr crystals necessitated redetermination of its structure and revision of its description, along the lines of the isostructural compounds BiSCl, BiSBr and SbSeI. The cell constants are: a = 8.2424(6), b = 9.7556(4), c = 3.9680(2) Å, Z = 4; space group Pnam . The…
Thin foils of polycrystalline α‐alumina were reacted with a potassium‐rich vapor at ≤900°C. Potassium β‐alumina formed along α‐alumina grain boundaries and protruded from holes in the foils. Conventional transmission electron microscopy was used to analyze the α‐alumina/β‐alumina phase boundary for possible orientatio…
Heterogeneously (film) and homogeneously low pressure chemically vapor deposited (“snow”) SiO 2 ‐ P 2 O 5 and SiO 2 ‐ GeO 2 glass samples have been prepared at various temperatures. Bulk glass samples have also been made by melting the oxides. High temperature transposed drop and solution calorimetry have provided the…
Crystals of yttria partially stabilized zirconia were grown by the arc‐image floating‐zone technique and studied by transmission electron microscopy. Crystals annealed at 1700°C consist of tetragonal precipitates and a cubic matrix. The platelike domains in a precipitate are twin‐related tetragonal variants stacked al…
To investigate the behaviour of hydrogen in irradiated iron at high temperature, electron-irradiation and defect analysis have been carried out in a high-voltage electron microscope after H+−ion implantation. After the implantation, visible interstitial-type loops were formed at room temperature. However, in iron impl…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRhodium-rhodium stretching frequencies in oxygen-16, oxygen-18, and trideuteromethyl derivatives of Rh2(O2CCH3)4(PPh3)2Robin J. H. Clark, Andrew J. Hempleman, and Colin D. FlintCite this: J. Am. Chem. Soc. 1986, 108, 3, 518–520Publication Date (Print):February 1, 1986Publica…
A new compound, 12SrO·7Al 2 O 3 , is formed from an amorphous material prepared by the simultaneous hydrolysis of strontium and aluminum alkoxides. It has a cubic unit cell with a =1.2325 nm. The structure contains tetrahedral AlO 4 groups and octahedral AlO 6 groups. This compound decomposes into 3SrO·Al 2 O 3 and Sr…
Abstract Reaction of mixtures of cobalt nitrate, colloidal silica, and a metal hydroxide (MOH) under hydrothermal conditions produced a range of cobalt hydroxysilicates, the components of which depended upon the identity of M, temperature, and reactant ratios. At 250°C, if M = Na, a smectite of composition Na 0.06 Co…
This paper presents the most significant results of multiyear research carried out in order to evaluate the thermal endurance properties of insulating materials. The thermal life model, proposed by Dakin, has been analyzed and compared with the experimental data; the importance of the selection of properties and their…
The system Ba 2 SiO 4 ‐Ca 2 SiO 4 was studied by heating mixtures of Ba 2 SiO 4 and Ca 2 SiO 4 at 1723 K. Six distinct phases resulted; they were examined by both X‐ray diffraction and differential thermal analysis. The phases β ‐(Ba 0.05 Ca 1.95 )SiO 4 and α‐(Ba 0.15 Ca 1.85 )SiO 4 are isostructural with correspondin…
The crystal structure of BiVO4, which has a monoclinic, distorted scheelite structure at ambient conditions, has been determined above the high-pressure transition at 1.6 and 4.3 GPa, and 23°C. At these pressures BiVO4 has the tetragonal scheelite structure, which is also observed at high temperature above 250°C at ro…