Materials Literature
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The molecular dynamics method is used to study the liquid–vapor interface of the Stockmayer fluid. We compare our results for the singlet density-orientation distribution function and surface tension with the predictions of integral equation and perturbation theory. We find that at low temperature and high moment cond…
Mixed crystals of potassium dihydrogen phosphate and ammonium dihydrogen phosphate (K 1- x (NH 4 ) x H 2 PO 4 ) have been investigated. Dielectric constants ε 11 and ε 33 and elastic compliance ( s 45°- Z ) on the 45°– Z -cut bars were measured. The crystals with \(0{\leqq}x{\lesssim}0.17\) show temperature dependence…
It is demonstrated that electronic structure calculations using the local-density approximation with density-functional theory accounts for the distinctly different behaviors in the equilibrium phase diagrams among Cu-Ag, Cu-Au, and Ag-Au alloy systems. A detailed microscopic analysis is made based on the prescription…
The temperature dependence of the resistance and of the Seebeck coefficient of ${\mathrm{TaSe}}_{3}$ were measured between 80 and 430 K. The Seebeck coefficient changes sign around 220 K, suggesting two-carrier transport. The magnitude of this coefficient at the ends of the temperature range and the poor metallic cond…
Effects of grain size, hardness, and stress on the magnetic hysteresis loops of AISI 410 stainless steel and SAE 4340 steel specimens were investigated experimentally. It was observed that both hardness and stress significantly influenced the hysteresis loops, while the grain size had a minimal effect. For each materi…
The Raman spectrum of hexagonal BaTiO 3 has been investigated in the temperature range from 2 K to room temperature. Below the structural-phase-transition temperature of T a (∼222 K), we find the corresponding underdamped soft-phonon modes; the mode frequencies are proportional to ( T a - T ) β with β∼1/3 in a wide te…
Contrast ratio is an important measure of the performance of an electrooptic display. From measurements of film brightness and transmittance, we determined contrast ratios of thin polymer films containing microdroplets of liquid crystalline material. Contrast ratios based on brightness were typically ~3 for all sample…
Ultraviolet photoelectron spectroscopy (UPS) and electron spectroscopy by deexcitation of metastable noble gas atoms (MDS) were used to follow the continuous oxidation of Cs films. While UPS has a finite information depth, MDS probes only the properties of the outermost atomic layer. Small doses of O2 cause the format…
We report time-resolved measurements of photoluminescence in bulk a-${\mathrm{SiO}}_{2}$ using 7.9- and 6.4-eV excitation. Time-resolved spectra have been obtained at room temperature and 25 K, and the intensity and decay rates of various luminescence bands have been measured as a function of temperature. Bands at 1.9…
The electronic structure of amorphous carbon and hydrogenated amorphous carbon (a-C:H) has been investigated through calculations on a number of model structures containing different configurations of ${\mathrm{sp}}^{2}$ and ${\mathrm{sp}}^{3}$ sites. We find that the most stable arrangement of ${\mathrm{sp}}^{2}$ sit…
Two important factors that determine the mechanism and temperature of the alpha - beta phase transition in solid oxygen are analysed: the magneto-elastic coupling which increases the temperature of the transition, and the antiferromagnetic order in the beta -phase which stabilises this phase at low temperatures, thus…
Order parameters, as measured from N.M.R. experiments, are reported for a series of small rigid molecules dissolved in the liquid crystals N-(p-ethoxybenzylidene)-p′-n-butylaniline, Merck ZLI 1132, and a 55 wt per cent 1132 mixture of the two. Previous studies have shown that in this mixture the external electric fiel…
Neutron spin-echo measurements have been performed on the ionic system ${\mathrm{Ca}}_{0.4}$${\mathrm{K}}_{0.6}$(${\mathrm{NO}}_{3}$${)}_{1.4}$ around the glass transition temperature ${\mathrm{T}}_{0}$, in order to determine the time dependence of the density correlation function ${\mathrm{\ensuremath{\varphi}}}_{\ma…
Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafl…
The kinetics of tetrabutyl titanate catalyzed transesterification of dimethyl terephthalate with poly(tetramethylene ether) glycol of various molecular weight has been studied in the presence and absence of 1,4-butanediol. Detailed analysis of experimental data with a proposed kinetic model indicates that the equal re…
Tensile properties of polyethertherketone (PEEK) have been studied at 125, 25, and −100°C for thin films prepared with different thermal histories. Initial morphology was controlled by rate of cooling from the melt. Amorphous films resulted from quenching the melt, while semicrystalline films were obtained by cooling…
Hydrolysis of polyester fabrics with sodium hydroxide has been studied with a view to imparting hydrophilicity and other comfort-related properties to polyester textiles. Effect of reaction parameters such as treatment time concentration of alkali, and temperature on the extent of hydrolysis is examined and the modifi…
Abstract The 2,7‐diazapyrenium group (DAP 2+ ) combines the features of pyrene, of methylviologen, and of nucleicacid intercalators and may thus present a variety of interesting properties. The cations 1 and 2 and the bis‐diazapyrenium species 3 have been synthesized and shown to bind molecular anions like aromatic po…
A new, low bias tilt field-effect liquid crystal display (LCD) is presented with better image quality than supertwist or superbirefringence LCD’s at the same high level of multiplexing. In its positive contrast mode, the display image is black on white with virtually no inherent coloration and with a comparably large…
We have used surface extended x-ray absorption fine structure (SEXAFS) to study the local geometry around barium atoms on thermionic cathodes. On the surfaces of tungsten and tungsten-osmium alloy dispenser cathodes Ba is bonded to oxygen with a well-defined short-range order. The Ba-O distance is similar (2.62\ifmmod…