Materials Literature
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Transverse magnetoresistance for paramagnetic ${\mathrm{Mn}}_{x}{\mathrm{TiS}}_{2}$ $(0.02<~x<~0.25)$ crystals has been measured at three fixed temperatures 77, 4.2, and 1.8 K at fields up to 31 T using a compact home-made pulsed magnet. We have found a large negative magnetoresistance $\ensuremath{\Delta}\ensur…
Integral skin foams consist of a cellular core and a near solid skin of the same material surrounding the core. A study of the effect of mica on the flexural properties of free rise and integral skin polyurethane foams is presented. Addition of a small amount of mica (5% v/v) is found to significantly increase the fle…
To evaluate the serviceability of a new textile product made of an unconventional fiber blend, it is important to determine if the fabric meets the specific standards required for the intended end-use. The value-added textile products of interest are fabrics made of 50/50 kenaf/cotton in the filling direction and 100%…
Shape memory alloys (SMA) show a high ratio of work capacity per material volume. This makes the application of SMA especially useful in micron-sized systems. The development of robotic grippers is one important prerequisite for the successful automation of the assembly of micro systems. Therefore the SMA may also pla…
The compounds Mn 8 [BeSiO 4 ] 6 X 2 (X = S, Se, Te) Mn 8 [BeGeO 4 ] 6 X 2 (X = S, Se) have been synthesized by solid state reactions of the constituent oxides and MnX at 1000−1100 °C in sealed quartz ampules. The materials crystallize with the cubic sodalite unit cell with an ordered Be/Z 4+ (Z 4+ = Ge/Si) framework i…
The structure of the superionic glass ${(\mathrm{L}\mathrm{i}}_{2}{\mathrm{S})}_{0.5}{(\mathrm{S}\mathrm{i}\mathrm{S}}_{2}{)}_{0.5}$ has been studied using Li-isotopic-substitution neutron diffraction. A marked difference has been observed in the intensity of the first sharp diffraction peak (FSDP) in the structure fa…
A student experiment is described concerning properties of ferromagnets near the Curie point. Gadolinium provides a good opportunity to determine the magnetic susceptibility above the transition point and to evaluate the critical exponent of the susceptibility. The temperature dependence of the electrical resistance o…
We present Cs2NaYF6:Ce3+ or Pr3+ as new x-ray storage phosphors. The radiation damage centers upon x irradiation were investigated using magneto-optical and magnetic resonance spectroscopy. F centers are the photostimulable electron trap centers. For the activator Pr3+ it could be shown that upon room temperature x ir…
Abstract Proton NMR second moments and spin-lattice relaxation times of polycrystalline C(NH 2 ) 3 PbI 3 and [C(NH 2 ) 3 ] 2 PbI 4 were studied in a wide temperature range. The order-disorder character of the existing solid-solid phase transitions was confirmed and for tetraiodoplumbate a new phase transition at 170 K…
Physicochemical and structural properties of microbial cell surfaces play an important role in their adhesion to surfaces and are determined by the chemical composition of the outermost cell surface. Many traditional methods used to determine microbial cell wall composition require fractionation of the organisms and c…
Secondary electron emission properties from crystalline and polycrystalline diamond films containing different boron concentrations were measured. The secondary electron yields δ were high. Yields were independent of incident beam angle and crystallographic orientation. The secondary electron yields were greatest for…
Transmission X-ray microscopy makes it possible to investigate biological specimens, i.e. cells and organelles, in their natural wet environment. The main processes determining the contrast in X-ray microscopy are photoelectric absorption and phase shift. X-ray microscopic experiments can therefore be carried out in b…
Sialons (Si−Al−O−N) are useful as engineering components because they combine the toughness of silicon nitride with phase stability. Competing reactions occur during conventional processing, making it difficult to form single-phase material without high-temperature/long-time heat treatments. Thermochemical insights in…
Abstract Racemization of optically active oligo- and poly(quinoxaline-2,3-diyl) derivatives with a single screw-sense, prepared by the polymerization of 3,6-diaryl-1,2-diisocyanobenzenes catalyzed by methylpalladium(II) initiator, was investigated. Pentameric and hexameric oligomers with a living palladium terminus we…
The birefringence and refractive indices of several liquid crystalline structures were measured throughout the visible wavelength region (400–900 nm) at different temperatures. Mixtures composed of members of the same homologous series were used in order to achieve the nematic phase at room temperature. Data on 28 mix…
We describe the experimental properties of metastable domains associated with the presence of an Inversion Wall (IW) and observed with homeotropically anchored nematic and cholesteric liquid crystals sandwiched between parallel glass plates. Such a distorted situation, stabilized by the application of an electric fiel…
By analytically solving some simple models of phase-ordering kinetics, we suggest a mechanism for the onset of nonequilibrium behavior in colloid-polymer mixtures. These mixtures can function as models of atomic systems; their physics therefore impinges on many areas of thermodynamics and phase ordering. An exact solu…
Diamond films of various thicknesses (1.5–12 μm) deposited on Pt (111) by microwave enhanced chemical vapor deposition (CVD) were studied by scanning electron microscopy (SEM) observation and x-ray diffraction pole figure measurements. The dependence of the surface morphology and structure of the films on the film thi…
We have studied the structure of bulk amorphous GaSb using the extended x-ray-absorption fine-structure (EXAFS) technique over the temperature range from 80 K to 293 K. The possibility of the presence of chemical disorder has been explored throughout the temperature range. The configurational (static) contribution to…
It is shown that the activation energy of a chemical reaction depends mainly on the difference between the hardness of the initial state of a reaction and the hardness of the transition state, that these two quantities may be estimated from the softnesses of the reacting molecules and the softnesses of the molecular f…