Materials Literature
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We introduce a microscopic model for the phase separation in block copolymers and carry out Monte Carlo simulations in two dimensions. We find that the equilibrium structure function satisfies a scaling relation with ${D}_{\mathrm{eq}}$, the thickness of the microdomains. We also find that ${D}_{\mathrm{eq}\mathrm{\en…
The authors have calculated the phonon dispersion curves of barium titanate (BaTiO 3 ) in the cubic phase. A nonlinear shell model is used, in which the fourth-order anharmonic core-shell interaction of the oxygen ion is considered within a self-consistent phonon approximation. The temperature dependence of the ferroe…
The use of obliquely SiO evaporated glass plates at grazing incidence and controlled thickness gives a surface twofold degenerate oblique orientation for the nematic liquid-crystal MBBA (p-methoxy-benzylidine-p-n-butyl-aniline). Using a horizontal electric field and the linear flexoelectric coupling, one can switch th…
The constant-NPT Monte Carlo method of statistical mechanics has been used to study a monolayer of hard oblate spheroids. The spheroids are free to rotate, but their centres are confined to a plane. Order parameters, configurational free energy, and singlet orientation distributions are calculated. It is found that or…
Abstract Asymptotic formulae are derived for the effective dielectric constants of composites containing densely packed spherical inclusions with dielectric constants differing greatly from that of the background. The asymptotic results are obtained by treating the influence of nearest-neighbouring inclusions analytic…
The synthesis, single-crystal x-ray structural characterization, and sorption properties of a microporous molybdenum phosphate, (Me(4)N)(1.3)(H(3)O)(0.7)[Mo(4)O(8)(PO(4))(2)] . 2H(2)O (Me, methyl), are presented. The three-dimensional framework is built up from Mo(4)O(8)(4+) cubes and PO(4)(3-) tetrahedra that are con…
The preferred grain orientation in polycrystals causes a direction dependence of the ultrasonic wave velocities. In an extensive study, the texture influence on different ultrasonic wave velocities is measured in series of cold‐rolled ferritic steel sheets. Based on that, ultrasonic techniques are developed to charact…
The authors present a general method for the generation of proper space fillings of Euclidean spaces with convex polytopes by projection from higher-dimensional spaces. As a special case, quasiperiodic tilings are obtained by the projection of periodic structures. The concept is general enough for the treatment of def…
Abstract Ultrahigh molecular weight polyethylene has been irradiated using a cobalt 60 source to give received dose between zeor and 50 Mrad. Irradiacted specimens were subjected to tensile characterization, dynamic mechanical analysis, and differential scanning calorimetry. Changes in tensile and dynamic mechnaical p…
Abstract The compounding of Kraft pulp with polypropylene was stuided using a laboratory higheshear roller blender. Dipsersion was characterized by measuring the size and number of agglomerates in a thin compression‐moldled sheet. The effects of parameters such as surface treatment and mixing conditions were investiga…
The dryout heat flux applicable to light water reactor fuel elements covered with porous deposits characterized by the presence of “steam channels,” or chimneys, is determined by the “wicking” or “choking” limit. The results of a study of these limits show that the dryout heat flux for thick, dense, or small particle…
Knowledge of the effective multiplication factor (keff) of variously configured damaged fuel at Three Mile Island Unit 2 (TMI-2) has greatly affected ongoing defueling operations. A recent DOT 4.3 discrete ordinates analysis has extended prior postaccident analyses of keff to “best-estimate”predictions of criticality…
Abstract The regularities of thermal degradation of Al(OH) 3 powders and the compositions of polydimethylsiloxane and fire retardant with different particle sizes (from 2 μm to 45 μm) were studied by the use of dynamic thermogravimetry (TG), mass spectrometry (MS) and high‐temperature pyrolysis. It was shown that the…
Abstract Recent studies have shown that the amount and rate of absorption of gases and organic liquids and vapors in rigid and plasticized PVC can be correlated with their molecular dimensions, solvent power, and thermodynamic activity. The amount absorbed at equilibrium depends upon the solvent power of the diffusant…
The electrical impedance of a disc-shaped sample of polycrystalline UO2 has been measured over a frequency range of 10 Hz to 10 MHz at temperatures between 108 and 380 K. Three distinct regions in the impedance profiles were observed; these have been associated with the region near the metallic electrodes, with the bu…
The successful preparation of Ta2S2C at 1150 °C has been found to be intimately linked to the presence of halogens in the reaction. Adventitious chlorine obtained either through the use of excess carbon or of graphite crucibles was apparently responsible for previously successful reactions. The purposeful introduction…
Abstract Unsymmetrically quinone-substituted porphyrin dimers were synthesized. The fluorescence of the both porphyrins in these models was effectively quenched by the attached quinone.
The Amphora species epiphytic on some freshwater species of fibulate diatoms is investigated and allocated to Amphora copulata var. epiphytica var. nov.
This study is the first to make a direct comparison between the distorting mirror and the distorting videocamera with the same group of nonclinical subjects. It also establishes the internal consistency, the test-retest reliability and the convergent validity of both techniques. Analysis indicates, as with other studi…
Stable icosahedral phases of Al-Fe-Cu and Al-Li-Cu, which are recognized as icosahedral quasicrystals corresponding to face-centered and simple 6D-hypercubic lattices, respectively, were examined by high-resolution electron microscopy with the incident beam parallel to the two-fold symmetry axis. Images observed were…