Materials Literature
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The energy distribution of the electrons backscattered in the direction of the surface normal of polycrystalline silver samples was studied using reflected electron energy loss spectroscopy (REELS) at 200 eV and 2 keV primary beam energies. For modeling the electron scattering processes, the Monte Carlo simulation tec…
The influence of poly(octadecyl acrylate) (PODA), which is a comb-like polymer with ethylenic side chains, on the crystallization and morphological behavior of high-density polyethylene (HDPE) in a binary blend was investigated. The studied parameters were the cooling rate, degree of crystallinity, spherulite size, an…
In this work, confirmation of the molecular formula and investigation of the structural stability of the prepared various types of heteropoly acids and their salts by TGA are reported. Specific surface areas of the samples were determined by the BET-single point N2 adsorption method. Scanning electron microscopy (SEM)…
A new design philosophy was tried out on a carbide-reinforced tool for hot working of stainless steel. The carbide particle in the micro structure of the new tool was selected so as to meet the relatively large optimum size. Attention has been focused, in the conventional tool, on the enlargement of the area fraction…
The electronic structures of the layered ternary tellurides Ta 3 Pd 3 Te 14 and Ta 4 Pd 3 Te 16 are examined. It is found that the presence of bicapped trigonal prismatic chains with extensive Te···Te interactions results in very wide tellurium-based bands along the direction of the chains. The local octahedral coordi…
This paper deals with optimization of a class of linear time-varying dynamic systems with n states and m control inputs commanded to move between two fixed states in a prescribed final time. Using a conventional procedure with Lagrange multipliers, it is well known that the optimal solution must satisfy 2n first-order…
In the electron-beam fabrication of interferogram-type diffractive elements, such as diffractive lenses, continuous fringes are often approximated by polygons to reduce the data volume. Local wave-front errors are then generated that scatter light and give rise to background noise. A roughness parameter beta is introd…
A thin, one-dimensional, gradient-index slab lens with a parabolic profile was designed and fabricated in fluorine-doped silica by use of plasma-enhanced chemical vapor deposition in a Helicon plasma reactor. The refractive-index profile of the fabricated lens was determined by the application of an inversion techniqu…
Pb- and Te-doped borosilicate glasses are transformed by appropriate heat treatment into a composite material consisting of a vitreous matrix in which semiconductor PbTe nanocrystals are embedded. This composite exhibits interesting non-linear optical properties in the infrared region, in the range 10–20 000 Å. The sh…
We analyze conformational stereoisomerism in the sterically hindered 4a,4b-dihydrophenanthrenes of C 2 symmetry. In these labile photointermediates, steric hindrance brought about by disubstitution at the 4 and 5 positions or by benzoannelation at the [c] and [g] bonds allows observation of two interconvertible interm…
We have demonstrated the evaluation of nonlinear optical properties and the determination of the molecular orientation of the mixed crystals of p -nitroaniline ( p -NA) and N -ethyl-4-nitroaniline (NENA) in powder form. Although neither material shows second-order nonlinearity due to the crystalline structure, the obt…
In order to develop an on-line system to characterize fabric bending rigidity, four potential loop shapes are proposed. Loop shapes are chosen such that they can be formed under dynamic conditions. Results from theoretical models of these loops show the nature of the response of loop shapes to varying fabric bending b…
Using an internally contracted multireference configuration interaction approach, threedimensional potential energy functions of the X2Σ+ (AlOH+) and X2Π (HAlO+) states have been generated. The variational calculations of the vibrational levels of AlOH+ showed that the large amplitude bending modes exhibit inverse anh…
The temperature dependences (80–500 K) of the Hall coefficient and the resistivity of samples of schungite of types I and III (schungite I and schungite III), as well as a commercial glassy carbon, with carbon contents equal to 98, 30, and 99.99%, respectively, are measured. The character of the dependences of the res…
The new compounds Cr(3)Si(2)O(7).(1)/(4)MX (MX = NaCl, NaBr, KCl, KBr) form a series of chromous disilicates hosting alkali-metal halides in a framework structure. Purple crystals with edge lengths up to 1 mm were prepared by reacting mixtures of Cr(2)O(3), Cr, SiO(2), and the respective alkali-metal halide in evacuat…
We report rotation of a single director in a nematic monodomain, acrylate based side-chain elastomer which was subjected to mechanical fields applied at angles in the range to the director, , present at the time of network formation. Time and spatially resolving wide angle X-ray scattering, together with polarised lig…
Abstract Well-formed crystals of chlorapatite [Ca5Cl(PO4)3] were first grown from a sodium chloride flux. The solubility of Ca5Cl(PO4)3 in NaCl increased with increasing temperature. At 1100 °C, Ca5Cl(PO4)3 had a solubility of about 0.15 mol%. The crystal growth of Ca5Cl(PO4)3 was conducted by heating a mixture of sol…
In this paper we present a 1-D model for the behavior of U-Nb shape memory alloys that accounts for the effect of plastic deformations on recovery strains. In particular, we account for the erasure of memory effect that occurs with increasing plastic strains. An algorithmic approximation to the model is discussed in d…
The properties of a series of stable diradicals based either on iminonitroxide (IN) or nitronylnitroxide (NN) are described. Both radical fragments are coupled by various phenylene and phenylethynylene (triple bond) bridges. They are characterized by EPR studies both in solution and in glassy state. Magnetic coupling…
Poly( S -thioester)s were successfully synthesized by a new addition reaction of bis(thiirane)s with diacyl chlorides catalyzed by quaternary onium salts or crown ether complexes. The polyaddition of Bisphenol A bis(2,3-epithiopropyl) ether (BPTE) or butanediol bis(2,3-epithiopropyl) ether with certain diacyl chloride…