Materials Literature
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The new pure silica polymorph ITQ-4, structure code IFR, Si32O64, monoclinic I2/m a = 18.65243(13), b = 13.49597(8), c = 7.63109(6) Å, β = 101.9781(5)°, is a zeolitic material containing a large sinusoidal channel with 12-member ring windows as minimum apertures. Its void volume (0.21 cm3/g) is surpassed only by that…
The dynamics of diglycidyl ether of bisphenol-A (DGEBA) was studied by employing broadband dielectric spectroscopy over a wide temperature range extending from below to above the glass-transition temperature. Dielectric spectra reveal the existence of two relaxation processes: the structural relaxation, slowing down f…
The characteristic sizes of perovskite ferroelectrics have been examined by mean-field theory in a three dimensional base, leading to a detailed evaluation of the ultimate limits of physical sizes in nanostructured ferroelectrics with the stable polar phase in situations where the influence of depolarizing field can b…
The irreversible electro-optical response (memory effect) of 'liquid crystal-aerosil' suspensions under the influence of an electric field is investigated. Thereby, the influence of the aerosil concentration on the efficiency of the memory effect is studied. The experimental results are discussed in the frame of a mod…
The curing of unsaturated polyesters in the presence of organic and inorganic fillers was studied by rheology and differential scanning calorimetry (DSC). A commercial resin was used as unsaturated polyester and pressed olive stones, which are an agricultural by-product, talc and quartz in different concentrations wer…
Evolved gas analysis−Fourier transform infrared spectroscopy was used to investigate the pyrolysis of tris(2,4-pentanedionato)aluminum on glass surfaces between 500 and 900 K in vacuum and in low-pressure water vapor atmospheres. Pyrolysis of tris(2,4-pentanedionato)aluminum in vacuum produced Al 2 O 3, carbon, water…
High-resolution ac calorimetry has been used to characterize the excess heat capacity $\ensuremath{\Delta}{C}_{p}(T)$ associated with the smectic-$A$ $(\mathrm{Sm}A)$ --hexatic-$B$ $(\mathrm{Hex}B)$ transition in $n$-hexyl-${4}^{\ensuremath{'}}\ensuremath{-}n$-pentyloxybiphenyl-4-carboxylate (65OBC). For temperature o…
A primary motivation for this research is the interpretation of nonclassical phenomena observed during the relaxation of highly viscous liquids, in particular those composed of polymeric materials. The chemical structure of macromolecules is well understood, and their syntheses are well monitored. This is probably not…
Solid‐state reaction and annealing of melts of samples in the R 2 O 3 ‐Ta 2 O 5 system (R is a rare‐earth element, i.e., La, Nd, Sm, Ho, Er, and Yb) revealed a defect‐fluorite phase (F‐phase) at high temperatures. The formation region of this F‐phase was in the region of ˜70‐80 mol% R 2 O 3 for small rare‐earth ions,…
This research explores the application of an image transform technique, the Hough transform (ht), to measuring fiber orientation distribution in nonwoven fabrics. In this paper, various forms of the ht for straight lines and the implementing algorithms are presented, the factors that may influence the accuracy of ht r…
Abstract The 3-regular (“3-connected”) nets with four and six vertices per unit cell are enumerated. The large number of nets obtained (five and 269, resp.) is in stark contrast to the small number (two and twelve, resp.) which are of crystallographic interest. This subset of crystallographically interesting nets is c…
Abstract The kinetic of the reaction of sand with aqueous NaOH corresponding to the ratio SiO 2 /Na 2 O = 2 was studied in a pressure vessel at 220°C and 2.7 MPa. Since the kinetic curves could not be obtained directly from the experimental data, a new method is proposed to plot the entire kinetic graph from experimen…
The utility of the growth mechanism to influence relative particle growth is investigated in a semi-batch reactor. A dynamic competitive growth model is developed and used to simulate the growth of two monodisperse polystyrene particle populations (bidisperse system) at 50 °C. Validation of the model with on-line dens…
Abstract. We study dynamical hysteresis in a simple class of nonlinear ordinary differential equations, namely first-order equations subject to sinusoidal forcing. The assumed nonlinearities are such that the area of the hysteresis loop vanishes as the forcing frequency tends to zero; in other words, there is no stati…
The sound radiation of 3-MHz acoustically driven air bubbles in liquid is analyzed with respect to possible applications in second harmonic ultrasound diagnostics devices, which have recently come into clinical use. In the forcing pressure amplitude Pa=1–10 atm and ambient radius R0=0.5–5 μm parameter domain, a narrow…
We describe a new method for assessing the Ca/P ratio of bone in vivo using gamma-ray photon absorptiometry. The theoretical approach of the method and the estimation of the variance are presented. Two radiation sources, Gd-153 (100 keV), and I-125 (27.5 keV), and a germanium detector were used to determine this ratio…
▪ Abstract The structural dependence of the optical and dielectric physical properties of liquid crystal (LC) materials is investigated with the aid of molecular modeling. A material characterization of LC materials is made using fundamental physical measurement values, e.g. optical, dielectric, elastic, and viscous p…
Blends of acrylic polymer (containing acrylonitrile 91.7%, methyl acrylate 7%, and sodium methyl propenyl sulfonate 1.3% [wt %], denoted as PAC) with silk fibroin (SF) were studied in the form of drawn fibers with varied compositions. The strength, elongation, and specific work of rupture of the blend fibers decrease…
Two series of polysiloxane-block-polyimides were synthesized by the method of solution imidization of the polyamic acids prepared from the dianhydride/diamine combinations of 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA)/2,2-bis[4-(4-aminophenoxy) phenyl] propane (BAPP) (Series A) and 3,3′,4,4′-benzophen…
Synthesis and Structure of a Binuclear Gadolinium(III) Complex: Magnetic Exchange Interactions in Alkoxy Bridged Lanthanide Complexes The Schiff Base ligand N ‐salicylidene‐2‐(bis‐(2‐hydroxyethyl)amino)ethylamine (H 3 sabhea) reacts with Gd(NO 3 ) 3 · 6 H 2 O in methanol solution to yield the alkoxy bridged binuclear…