Materials Literature
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A general framework for the theory of electron–intramolecular vibration (e–mv) interaction in charge-transfer (CT) compounds is presented, particular attention being devoted to the effect of this interaction on the optical spectra of quasi-one-dimensional organic semiconductors. The common physical basis of different…
We present the first direct calculation by simulation of the excess surface free energy of a crystal–liquid interface. We perform these calculations on the (111), (100), and (110) interfaces of a truncated Lennard-Jones face-centered-cubic crystal–liquid system at the triple point by the molecular dynamics technique.…
To utilize the excellent properties of silica (SiO2) glass for a glass laser host, neodymium-aluminum (Nd–Al) and neodymium-phosphorous (Nd–P) co-doped SiO2 glasses were studied. They were prepared by plasma-torch chemical vapor deposition (CVD). It was found that a doping level less than ten times the number of Nd fo…
Data are presented on the variation of the dielectric constant and the tribo-electric coefficient for a series of pigmented, melt mixed, polymer materials. Dielectric spectra are also presented for other pigmented polymeric materials. On the basis of these data it is shown that in certain situations a correlation may…
The transient hot-strip (THS) method has been used for thermal conductivity and thermal diffusivity studies of electrically conducting materials by introducing a thin electrically insulating layer between the hot strip and the metallic material under study. The insulating layer introduces a certain thermal contact res…
Caracteristique d'un lac de Finlande. Phyto-, bacteriozooplancton. Production primaire et respiration. Poissons
A decagonal quasicrystal with point group 10/mmm has been found in Al-14-at.%-Fe alloy. Zone-axis patterns of the decagonal phase appearing at the icosahedral positions are reminiscent of the appropriate icosahedral patterns. The symmetry and the angular separation of the zone axes can be obtained from the icosahedral…
A nematic liquid crystal should present an order electric polarization associated with the gradient of order parameter, in addition to the flexoelectric polarization associated with the gradient of orientation. Using thermodynamical arguments, we show that the order-electricity coefficients are of the same order as th…
Grain boundaries are known to reduce significantly the electrical dc conductivity of polycrystalline metallic materials. In this paper, we give a quantum mechanical calculation of the grain-boundary resistance based on the transfer-matrix approach. The results show an exponential decrease of the conductivity with resp…
The observation of very-low-frequency bands by Raman scattering in a nucleated cordierite glass is described. The frequency of the maximum of scattering is proportional to the inverse diameter of the particles, which are spherical spinel microcrystallites. It is shown that vibrational surface modes of particles are re…
Abstract A series of [BaxCsy][(Ti, Al)3+2x + yTi4+8-2x-y]O16 hollandites, synthesized at 1250°C and coexisting with ‘reduced ’ rutile, demonstrates complete solid solution between barium and caesium endmembers, and simultaneously between Ti3+ and Al3+. The presence or absence of rutile has only a minor effect on stoic…
Abstract Phosphorous, as sodium dihydrogen phosphate, and nitrogen, in the form of a urea–for‐maldehyde condensate, were applied to cotton fabric. The flame‐retarding character of each treated fabric was assessed by determining the respective limiting oxygen index. Analysis of the results showed that at the lowest lev…
Abstract Radiation induced graft copolymerization of ethyl acrylate onto sisal fibers was investigated. It was fond that the percent added‐on of ethyl acrylate to sisal fibers was prohibitively low when using the direct grafting method due to excessive hompolymerization. The preirradiation method was found to be inval…
Abstract Two hydroxy‐functionalized liquid rubbers, one a commercially available polybutadiene (PB) and the other a specially synthesized polymyrcene (PM), have been converted into homopolyurethane elastomers by reaction with 4,&4prime;‐diphenylmethane diisocyanate (MDI). Additionally, PB and PM, each in admixture…
We have measured Young's modulus $Y$ and internal friction $\ensuremath{\delta}$ of the charge-density-wave (CDW) conductors Ta${\mathrm{S}}_{3}$ and Nb${\mathrm{Se}}_{3}$, in the presence of combined ac and dc electric fields. In the pinned CDW state, the elastic properties are sensitive to even small ac-field amplit…
Poly(2-ethyl-2-oxazoline) is prepared by the ring-opening polymerization of 2-ethyl-2-oxazoline with a cationic initiator. Many of the polymer's characteristics stem from its molecular structure, which has a backbone of alternating two carbon atoms and one nitrogen with a pendent propionyl group off the nitrogen. Rheo…
We report experimental studies of the statics and dynamics of diffusion-limited polymerization. The fractals obtained were produced electrochemically from neutral precursors, and have a Hausdorff dimension of 1.74\ifmmode\pm\else\textpm\fi{}0.03. The width of the active growth zone increases at the same rate as the fr…
Abstract Dipole relaxation dielectric loss behavior of a fiberglass–epoxy composite has been studied as a function of moisture uptake. A single widely distributed loss peak, centered at −16°C for 10 kHz measurement, is observed in the dry composite. Very low moisture concentrations (<0.1%) interact with the composi…
We suggest that dendritic sidebranches may, under some circumstances, be generated by selective amplification of noisy fluctuations near the tip. Our proposal is based on numerical and analytic studies of the dynamics of the two-dimensional boundary-layer model with kinetic crystalline anisotropy. Certain features of…
Abstract not Available.