Materials Literature
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Nanocomposites (Si 3 N 4 /SiC) were studied by combined high‐resolution transmission electron microscopy and electron energy‐loss spectroscopic imaging (ESI) techniques. In ESI micrographs three types of crystalline grains were distinguished: Si 3 N 4 matrix grains (0.5 μΩ), nanosized SiC particles (<100 nm) embedd…
The third‐order nonlinear optical properties of donor‐acceptor substituted tetraethynylethenes (see figure and also the preceding contribution) are presented with special emphasis on the structure‐property relationships and the effect of conjugation paths on the optical nonlinearity. In one single class of materials t…
We have measured the subpicosecond optical response of a solid-state, semiconductor-to-metal phase transition excited by femtosecond laser pulses. We have determined the dynamic response of the complex refractive index of polycrystalline VO2 thin-films by making pump-probe optical transmission and reflection measureme…
Various blends of a commercial bismaleimide (BMI) mixture, a cyanate ester (CE) and a co-monomer with allyl and cyanate pendant groups were formulated and cured. Differential scanning calorimetry (DSC) data were used to monitor the cure of neat resins, while dynamic mechanical thermal analysis (DMTA) was used to asses…
The thermal conductivity of chemically, structurally, and isotopically highly pure germanium single crystals is investigated experimentally in the temperature range from 2 to 300 K. It is found that the thermal conductivity of germanium enriched to 99.99% 70 Ge is 8 times higher at the maximum than the thermal conduct…
This article describes properties of composites of collagen-hyaluronic acid shaped to layered materials. According to the results, interactions of these two polymers are very strong. The properties can be influenced by chemical crosslinking using glyoxal and starch dialdehyde. The different behavior during enzymatic d…
A function f 2 L 1 (R) tiles the line with a constant weight w using the discrete tile set A if P a2A f(x \\Gamma a) = w almost everywhere. A set A is of bounded density if there is a constant C such that #fa 2 A : n a n + 1g C for all integers n. This paper characterizes compactly supported f 2 L 1 (R) that admit a t…
A borosilicate glass of molar composition 0.${01\mathrm{E}\mathrm{u}}_{2}$${\mathrm{O}}_{3}$\ensuremath{\cdot}0.99(${25\mathrm{N}\mathrm{a}}_{2}$O\ensuremath{\cdot}${50\mathrm{B}}_{2}$${\mathrm{O}}_{3}$\ensuremath{\cdot}${25\mathrm{S}\mathrm{i}\mathrm{O}}_{2}$) has been studied through the optical spectroscopy of the…
Diatoms (Bacillariophyceae) are a widely distributed group of microscopic, unicellular algae that are characterized by siliceous cell walls (frustules). The size, shape and sculpturing of diatom frustules are taxonomically diagnostic. Moreover, because of their siliceous composition, diatoms are often well preserved i…
A method to prevent the reduction of CuO formed on Cu metal during x-ray photoelectron spectroscopy analysis is presented. When a bias voltage of -250 V was applied to the sample surface in the case of non-monochromatic Mg Kα1,2 irradiation, the reduction of CuO to the lower oxide (Cu2+Cu+) was suppressed by 80–90% as…
ABSTRACT Mechanical and barrier properties of corn zein films with butylated hydroxyanisole (BHA), bacterial enzyme, and emulsifier additives were investigated and compared to those of polyvinylidine chloride (PVDC) films. No significant differences (P < 0.05) occurred in elongation, tensile strength, or Young's mo…
Abstract The reaction of cellulose with methoxy‐substituted triphenylmethyl chlorides under homogeneous conditions in the presence of pyridine was carried out with the aim to develop new protective groups for cellulose simply introducable and completely removable under mild conditions. The obtained cellulose ethers di…
Refractory oxide barrier coatings are a promising approach for improving the environmental durability of silicon‐based ceramics in severe environments. The oxidation durability of a newly developed fully crystalline mullite coating on SiC and SiC/SiC composites was investigated under thermal cycling between room tempe…
The first four cumulants of a radial distribution function of diatomic molecules and the first three cumulants for linear triatomic systems have been derived quantum statistically. These moments are directly related to the second- to fourth-order force constants of the chemical bond. The temperature dependence of exte…
Abstract Vulcanization kinetics for a SBR compound was studied by using both curemeter and DSC methods by a kinetic approach. A simplified but realistic model reaction scheme was used to simulate both induction and curing periods simultaneously. Model parameters were extracted from isothermal curemeter experiments. Th…
Abstract Sulfur-cured SBR vulcanizates are devulcanized by high power ultrasonic irradiation in a continuous process under various processing conditions. Crosslink density and gel fraction of devulcanized rubber are measured. The unique dependence of crosslink density on gel fraction of devulcanized samples obtained a…
Calcined (Ba 0.8 Sr 0.2 )(Ti 0.9 Zr 0.1 )O 3 (BSTZ) with added CuO is used as an improved material with which to fabricate surface (or reduction-reoxidation) barrier layer capacitors (BLCs). The CuO-containing BSTZ appears to have less temperature, frequency, and bias dependence of the dielectric characteristics and a…
A new powder diffractometer for synchrotron radiation with six detector arms has been constructed. Five detector arms are attached radially at intervals of 25 degrees to the 2theta axis and form a multiple-detector system. Five scintillation counters coupled with flat Ge(111) crystal analyzers on the respective arms c…
We have examined the adsorption of CO, NO, and H2on modelPd/ceria catalysts, formed by vapor deposition of Pd metal ontoa flat, polycrystalline ceria support, using temperatureprogrammed desorption. For CO adsorption on freshly deposited Pdfilms, a substantial fraction of the CO reacts to CO2in TPD,between 450 and 550…
The embrittlement of poly(hydroxybutyrate), and its copolymers with hydroxyvalerate, on storage at room temperature has been considered in the light of the relaxation of the interlamellar glassy regions and also the development of secondary crystallisation. From a study of the kinetics of the two processes, the first…