Materials Literature
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The crystal structure of the new germanium selenide Ge4Se9 has been determined by powder X-ray diffraction. It shows a new feature for this class of compounds; corner sharing of tetrahedra via Se2 dimers with short Se–Se bonds. Structurally, Ge4Se9 is related to GeSe2 in that the edge-sharing tetrahedra in ambient pre…
Undoped ZnO films were deposited on Si substrates by DC reactive sputtering. The samples were annealed in air, pure O2 (1atm) and pure N2 (1atm) at 850℃,950℃,1000℃ for 1h. The X-ray diffraction patterns of the as-deposited and annealed samples all have a widened diffraction peak of ZnO (002). It is evident that all th…
The entropic contribution to the redox energetics of the grossly disordered high-temperature phase SrFeO3−δ is derived from the heat capacities of SrFeO2.500, SrFeO2.725 and SrFeO2.833 determined by adiabatic calorimetry. All three samples are structurally and magnetically ordered at low temperatures and the calorimet…
The solute redistribution law that predicts non-equilibrium phase constitution in compositionally cored binary alloys is usually attributed as Scheil's equation. Earlier studies on this subject by G. H. Gulliver are occasionally cited but are thought by some to be either approximate or incomplete. It is shown that Gul…
Core levels of silicon and carbon in the hexagonal form of silicon carbide have been studied by x-ray photoelectron spectroscopy. For this purpose, zirconium Lα (energy = 2042.4 eV) and magnesium Kα (energy = 1253.6 eV) radiations have been employed. The XPS data in the silicon 1s, 2s, 2p, and Auger KLL, and carbon 1s…
Considerable effort has gone into developing polymer formulations and cable designs to minimize failures through water tree growth. However, diagnostic techniques still are required to enable the estimation of the level of damage present within a service cable. This paper reports on progress regarding the application…
Optical diagnosis for aged mica-epoxy insulation of HV (3.0 to 6.6 kV), enclosed induction motors used in compressors has been studied. The developed optical fiber sensor consists of two optical fiber cables (one for light transmission, the other for light reception; each /spl sim/3 m long), two types of laser diodes…
The existing approaches to the detection of precipitation are largely based on room temperature measurements on quenched samples. However, the direct measurement of precipitation kinetics at high temperatures is also possible through analysis of the mechanical properties of the specimens. In this work, a creep method…
A great deal of mineralogy has focused on determining crystal structures of minerals. Amorphous materials are often compared to crystalline materials of the same composition in order to predict atomic structure in the disordered phase. However, there are many instances when such analogies will break down or no crystal…
A new stable icosahedral quasicrystal has been found in annealed Cd-Mg-Dy alloys. The composition of the icosahedral phase was determined to be approximately Cd66Mg21Dy13. Powder X-ray and electron diffraction patterns revealed that the phase has a primitive icosahedral lattice with a quasilattice parameter aR = 0.563…
A new dialdehyde monomer, 4,4′-(hexafluoroisopropylidine) bis(p-phenoxy) benzaldehyde, was prepared; it led to a number of novel poly-Schiff bases in reactions with different diamines, such as 4,4′-diaminidiphenyl ether, 4,4′-(isopropylidine) bis(p-phenoxy) dianiline, 4,4′-(hexafluoroisopropylidine) bis(p-phenoxy) dia…
Theoretical investigations (Density-Functional Tight-Binding-DFTB) about the functionalization of single wall carbon nanotubes (SWNTs) by fluorination are reported. It is shown that side-wall modified nanotubes may show a wide variety of electronic properties, but may open also possibilities for tailoring solubility a…
Severe stress conditions of modern structures and strict weight limitations call for continuous refining of the methods of strength and analysis and optimization of the technologies. This is the first handbook containing extensive information on the influence of the stress on the material properties. Strength and plas…
X-ray diffraction, optical absorption and photoluminescence were measured for anatase titanium dioxide under high pressures using a diamond anvil cell. Pressure dependence of the lattice constants was determined. Absorption spectra revealed that the absorption edge of anatase shifts at a rate of 10 meV/GPa. A broad lu…
A new series of perbrominated 2-nitro-5,10,15,20-tetraphenylporphyrins, H2TPPBrn(NO2) (n = 6 and 7) and their metal (CuII and ZnII) complexes have been synthesised and characterised. The presence of mixed electron withdrawing (bromo- and nitro-) substituents at the β-pyrrole positions induces interesting electrochemic…
The phase separation behavior of polymer blends modified by copolymer additives has been studied using light scattering techniques. Block and random copolymers with equal styrene and butadiene content as well as a random copolymer with unequal monomer composition were used as additives at a concentration of 2.5% (w/w)…
An opticallybased system for measuring cotton flow rate was designed and tested in both field and laboratoryenvironments. Accuracy was documented by comparing actual and predicted load weights. When fieldtested on a cottonharvester, results were positive, with an average absolute error of 4.7%. A laboratory test was s…
Transient liquid phase (TLP) bonding process of Ni using Ni–11.0 mass%P binary filler metal was simulated by using a mathematical model based on diffusion analysis. In the model, diffusion-controlled transformation was assumed, and the base metal dissolution in the early stage and the subsequent isothermal solidificat…
Stress-dependence of the intrinsic time of viscoelastic materials is investigated.The influenceof stress level on the intrinsic time is considered to be similar to that of lemperature,pressure,solvent con-centration,damage and physical aging.The time-lemperature-stress equivalence principle is proposed,byemploying whi…
The fabrication of carbon nanotube emitters with excellent emission properties is described. The nanotubes synthesized by arc discharge are used as electron emitters. The fibrous bundles containing nanotubes were crushed, mixed with conductive pastes, and slurries and then screen printed. The scanning electron microsc…