Structural stability of crystalline compounds
A Comment on the Letter by D. G. Pettifor and R. Podloucky, Phys. Rev. Lett. 53, 1080 (1984).Received 23 January 1985DOI:https://doi.org/10.1103/PhysRevLett.55.260©1985 American Physical Society
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Nonlinear theory of domain walls and the anomalies of intercalation kinetics
A nonlinear theory of domain walls in intercalation compunds is presented. Realistic domain-wall energies and barriers to the relative motion of intercalate domains are calculated for the entire range of guest species intercalating into graphite. The different stackings of host layers found in stage-2 compounds are st…
Theory of the hcp-fcc transition in metals
A theory is developed for the hcp-fcc structural phase transition in close-packed metals as a function of the average electron concentration per atom. It is found that the transition can be continuous at low temperatures. Ordered polytypic stacking sequences are found near the transition point. Short-period structures…
Light-scattering study of a polymer nematic liquid crystal
We study the relaxation of thermally excited orientation fluctuations in a polymer nematic liquid crystal using photon correlation spectroscopy. The material studied is poly-\ensuremath{\gamma}-benzyl glutamate at a concentration just above the isotropic to nematic transition point. The relaxation rates of elastic def…
An unusual guanyl oligonucleotide regulates cellulose synthesis in Acetobacter xylinum
The mechanism of GTP-specific activation of the membrane-bound cellulose synthase system of Acetobacter xylinum has been further elucidated. The supernatant fraction derived from washed membranes of this organism contains an enzyme which reacts with GTP to form a low molecular mass, heat-stable compound,tentatively ch…
Direct observation of two-dimensional, dynamic clustering and ordering with colloids
We describe a system where the dynamics of reversible clustering, ordering, and growth in two dimensions can be directly observed. The system consists of uniform colloidal particles trapped at an air/water interface. We attribute the attraction between particles mainly to pairwise potential with a longer-range van der…
Opportunities in Magnetic Materials
Recent discoveries of new magnetic materials may greatly improve the performance of devices containing such materials and may lead to entirely new applications. For example, boron-based temary compounds for permanent magnets make new compact motor designs practical; amorphous transformer materials show greatly reduced…
Finite element simulation of time dependent fracture and fragmentation processes in rock blasting
Abstract Two constitutive models for the simulation of fracture and fragmentation processes in rapidly loaded rocks are studied. The models were included in a wave propagation finite element code. The results obtained from the two models were compared by a study of the intensity and extent of fracturing obtained from…
A model for the different crazing behaviour of amorphous polymer glasses
A molecular-level analysis that explains the differences in crazing behaviour encountered in polymeric glasses is presented. Considering the separation of molecules or segments of them as the controlling mechanism for crazing (at the initiation stage), it is found that in vinyl polymers such as polystyrene and polymet…
Fundamental Aspects of Polymer Degradation By High-Energy Radiation
Understanding of the mechanism of radiation degradation of polymer molecules is essential for development of improved and new industrial processes, for radiation-induced modification of polymer properties, and for selection of polymers for use in radiation environments. This means that the detailed chemical reactions…
Safety Evaluation of the Blanket Comparison and Selection Study
The results of the safety evaluation of the Blanket Comparison and Selection Study (BCSS) are presented. The safety evaluation measured the relative safety and environmental attractiveness of the final group of BCSS blanket concepts for application with either a tokamak or tandem mirror fusion reactor. Two types of bl…
Dielectric studies inN- (p-n-butoxybenzylidene)p-n-butylaniline
The dielectricconstant variation with temperature of N-(p-n-butoxybenzylidene)p-n-butylaniline is presented in the isotropic, nematic, smectic A and smectic B phases. A new transition in the nematic phase is reported. The derived parameter, molar susceptibility anisotropy, Δσ, is also determined.
Hydroliquefaction of Illinois No. 6 coal using iron pentacarbonyl
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydroliquefaction of Illinois No. 6 coal using iron pentacarbonylToshimitsu Suzuki, Osamu Yamada, Katsuhisa Fujita, Yoshinobu Takegami, and Yoshihisa WatanabeCite this: Ind. Eng. Chem. Process Des. Dev. 1985, 24, 3, 832–836Publication Date (Print):July 1, 1985Publication His…
The Phase Diagram of TbPO4 Measured by Linear Optical Birefringence
Abstract Measurements of the linear optical birefringence are used to determine the B–T phase diagram of TbPO 4 down to 1.5 K for two principal field directions. There are three ordered phases, a simple antiferromagnetic one with the moments along the tetragonal c ‐axis below T N1 = 2.28 K, a further colinear antiferr…
Corrosion of V 3TI 1SI in Flowing Lithium
The application of vanadium alloys as structural materials for the first wall or blanket of a fusion reactor will depend strongly on their compatibility with the coolants and breeding materials included in the blanket system. In the case of the use of liquid alkali metals, lithium offers the advantage of being an exce…
Effects of Heat on Cotton, Polyester, and Wool Fibers in Blended Fabrics - A Scanning Electron Microscopy Study
Treating cotton textile fabrics with phosphorus-containing flame retardant finishes reduces the flammability of the fabrics. The presence of fibers other than cotton in blended fabrics changes the burning rates and char lengths of the fabrics, as well as the nature of the resultant chars. To better understand the rela…
Structure refinement with X‐ray powder diffraction data for synthetic calcium hydroxyapatite by Rietveld method
Abstract Ca 5 (PO 4 ) 3 OH, M r = 502.3, hexagonal, P 6 3 /m, a = 9.4207(3), c = 6.8780(2) Å, V = 528.67 Å 3 , Z = 2, D x = 3.156 Mg · m −3 , CuKα, λKα 1 = 1.54051, λKα 2 = 1.54433 Å, μ = 26.25 mm −1 , F(000) = 500, T = 294 K. The powder diffraction pattern was analysed by the Rietveld method. The parameters were refi…
Focal shifts in parabolic reflectors
Given a parabolic reflector, the maximum directivity is not always achieved by placing the feed at the focal point. Depending on the nature of the feed, the maximum directivity can be obtained by axially displacing the feed either toward or away from the reflector. For low-tapered feeds, the shift should be toward the…
Program construction for macromolecule atomic model refinement based on the fast Fourier transform and fast differentiation algorithms
Structure refinement may be considered as a minimization of a function R(χ) of a large number of refineable parameters. A new type of function incorporating phase probability distribution is proposed. The minimization of the function utilizing gradient methods requires the computation of gradient ∇R, as well as the pr…
Thermomechanical Testing of Beryllium for Limiters in ISX-B and JET
Materials testing of S-65-B grade beryllium has been conducted in order to evaluate the use of this material for limiter surfaces in the ISX-B and JET tokamaks. Selected thermal and mechanical properties were measured at temperatures up to 700 °C. These measurements revealed that S-65-B has exceptionally high ductilit…