Materials Literature
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We show that under compression on a Langmuir trough, a surfactant monolayer may have a mechanical instability similar to the buckling instability of a beam or a plate. In the buckled state, the wavelength of the surface undulations is the capillary length resulting from the balance between gravity and curvature energy…
A bismuth sodium titanate, (BiNa)1/2 TiO3 (BNT)-based solid solutions, (1−x) (BiNa)1/2TiO3 + x(a·SrTi03 +b·PbTiO3 +c·CaTiO3) (a + b + c = l), (BNTX [100x-100a/100b/100c]), were studied for their dielectric, piezoelectric and pyroelectric properties. X-ray diffraction data show that a rhombohedra1 (Fα-tetragonal (Fβ) p…
The intense acoustic wave generated at the focus of an extracorporeal shock wave lithotripter is modeled as the impulse response of a parallel RLC circuit. The shock wave consists of a zero rise time positive spike that falls to 0 at 1 microsecond followed by a negative pressure component 6 microseconds long with ampl…
The roots of the chemistry of conventional rod-like liquid crystals are briefly considered. The low-molecular-weight liquid crystals are analysed in terms of rigid groups (rod-like and disc-like ring systems), flexible groups, polar groups and short, linking segments. On the basis of this analysis, the liquid-crystall…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid-state CP/MAS carbon-13 NMR study of cellulose polymorphsAkira Isogai, Makoto Usuda, Takashi Kato, Toshiyuki Uryu, and Rajai H. AtallaCite this: Macromolecules 1989, 22, 7, 3168–3172Publication Date (Print):July 1, 1989Publication History Published online1 May 2002Publi…
The phase, designated as Sm C A * , which shows tristable switching was investigated in C 8 H 17 O– - -COO– -COO * CH(CH 3 )C 6 H 13 (MHPOBC) by means of thermal analyses, a miscibility test and microscope observation. The phase transition from Sm C * to Sm C A * is not observable by AC calorimetry but small peaks com…
At least two antiferroelectric liquid crystalline phases were discovered in MHPOBC. These phases appear below the usual ferroelectric Sm C * phase. Because of the alternation of the molecular tilt directions as well as the dipole orientations in successive layers, the optic axis is along the layer normal. This strong…
Motivated by recent mean-field theories of the structural glass transition and of the Potts glass model we formulate a scaling and droplet picture of an assumed ideal structural glass transition. The phase transition is a random first-order phase transition where the supercooled-liquid phase is composed of glassy clus…
The thermal boundary resistance present at interfaces between helium and solids (Kapitza resistance) and the thermal boundary resistance at interfaces between two solids are discussed for temperatures above 0.1 K. The apparent qualitative differences in the behavior of the boundary resistance at these two types of int…
This book is devoted to the fundamentals of the theoretical analysis of phase equilibrium diagrams. Phase diagrams are known to play an important role in met allurgy and materials science, chemical engineering, petroleum refining, etc. A study of phase diagrams can help in choosing the optimal composition of mixtures…
We report the first explicit measurements on the profile of a spreading edge of nonvolatile liquid, in support of the theory of Hervet and de Gennes on a one-dimensional thin spreading edge. From the laser light interference patterns, the meniscus shape of the edge was reconstructed and the advancing dynamic contact a…
Thin films have been deposited in a ‘‘dual frequency mode’’ plasma, in which differing amounts of radio frequency (rf, 13.56 MHz) power were applied to the substrate, while sustaining the plasma with constant microwave (2.45 GHz) power. We report results pertaining to deposition of silicon oxide and organosilicon thin…
We show that a layer rigidity model which includes the effects of elastic deformations of the host layers can account for the composition dependence of the c-axis lattice expansion of a variety of layered intercalation compounds. Rigidity parameters deduced from this model for each of the three classes of layered soli…
The pressure dependence of the magnetisation of Y 2 Fe 17 , Y 6 Fe 23 and YFe 2 at 4.2 K has been deduced from forced volume magnetostriction measurements in fields up to 12 T. The pressure dependence of the 89 Y hyperfine field in the above compounds and YFe 3 has been measured using NMR. The results are consistent w…
The authors have analysed the cathodoluminescence spectra from single-crystal diamonds grown by the decomposition of a methane-hydrogen mixture in a microwave plasma. Crystals grown using methane concentrations of <or approximately=1% exhibit 'edge emission' at around 5.3 eV due to the recombination of free excitons i…
Abstract The decay of polyenyl macroradicals in irradiated poly(vinylidene flouride) and its dependence on radiation crosslinking was studied by the ESR method. The decay rate constants were found to decrease in the lower temperatures region but they show some anomaly at higher temperatures with respect to radiation d…
Incoherent neutron scattering (INS) experiments have been performed on various polycrystalline derivatives of decylammonium manganese tetrachloride. This compound displays a solid state phase transition, often referenced as a ‘chain melting process’, quite similar to that observed in lipid membranes. The quasi-elastic…
Abstract Cellulose tricarbanilates (CTCs) were prepared from a range of cellulose samples (cotton linters, wood pulps, Avicel, amorphous cellulose, and cellulose II) for molecular weight distribution (MWD) studies by high performance size exclusion chromatography (HPSEC). The HPSEC columns were calibrated using CTC st…
Abstract Cellulose fractions of different molecular weights were subjected to dynamic thermogravimetric analysis in a nitrogen atmosphere. From the experimental data, activation energies and reaction orders were obtained following the Freeman–Carroll and Broido methods. The thermal stabilities of the samples were esti…
The crystal structure of α-methanol at 15K has been determined from neutron powder diffraction measurements. The structure is orthorhombic, space group P212121. The molecular geometry is found to be very similar to that in the gas phase, but the methyl group no longer has ideal 3-fold symmetry. The crystal is formed b…