Materials Literature
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As part of an effort to develop high performance/high temperature materials for composite fabrication via resin transfer molding (RTM) and resin infusion (RI), phenylethynyl-containing imide oligomers (PEIs) have been investigated. Uncured resins with low and stable melt viscosities and when cured, high glass transiti…
A concept combining optics and microwave pulses with the negative charge-state of the nitrogen-vacancy (NV—) center in diamond is demonstrated through experiments that are equivalent to single-qubit gates, and decoherence for this qubit is examined. The spin levels of the ground state provide the two-level system. Opt…
Thermal analyses (DTA and TG) were carried out on sturmanite and ettringite from the Kalahari Manganese Field, South Africa. The TG trace for sturmanite, approximately Ca6(Fe 3+ 1.5Al0.3Mn 2+ 0.2)2.0{[B(OH)4]1.2(SO4)2.3}3.5(OH)12•25H2O, indicates that H2O(g) is lost at about 135°C, SO3(g) is lost at about 1349°C, and…
Hexafluoro-2-propanol (HFIP) exhibits a unique ability to release and activate H2O2 from the urea-hydrogen peroxide adduct (UHP). This UHP/HFIP system was investigated in epoxidation of olefins, using various fluoroketones as catalysts. With reactive olefins, no catalyst was required. With monosubstituted olefins, epo…
Pré-polímeros fenólicos e lignofenólicos (substituição de 40% em massa de fenol por lignina, extraída do bagaço de cana) foram sintetizados para preparar compósitos com matrizes termofixas, usando bagaço de cana-de-açúcar como agente de reforço. Este material lignocelulósico foi modificado por métodos químicos e/ou fí…
The Favimat, a single fiber testing machine, is used to quantify the affects of cotton crimp on fibers from three samples consisting of cottons containing low, high, and ideal micronaire values for textile processing. In order to get a better representation of all fibers within these samples, the cotton is further div…
Abstract The principle of multilayer interphases was proposed earlier for modifying the mechanical properties and UV stability of various multicomponent polymer systems. This paper focuses on the applicability of this principle for improving the performance of intumescent flame‐retardant systems using melamine‐treated…
The first synthesis and characterization of gold−silica core−shell nanoparticles with a mercaptosilane interface between the core and shell is reported. These nanoparticles exploit the strong interaction between thiols and gold to create a well-defined interface of functional group organization between core and shell.…
Crystalline nanobelts of ZnO and SnO2 were prepared from a thermal evaporation of oxide powders inside an alumina tube in the absence of catalysts. Typical dimensions of the nanobelt samples ranged from approximately 10 to 100 microns in length, 30 to 300 nm in width, and 6 to 30 nm in thickness. Room temperature Rama…
In the present study the thermal decomposition of a freeze-dried copper(II) acetate monohydrate powder, (CH3COO)2Cu.H2O, (FDCuAcH2O), was analysed by a combination of high-temperature X-ray diffractometry; differential scanning calorimetry and thermogravimetry, up to 700 °C. The structure and morphology of the calcine…
Cu x S ( x → 2) thin films were obtained by sulfidization of copper thin films previously obtained by spin-coating from a dichloromethane solution of [Cu(II)(2-ethyl hexanoate) 2 (H 2 O) 2 ] deposited on ITO substrate, irradiated with UV light and electrochemically reduced. Through cyclic voltammetry experiences perfo…
Proton-controlled reversible inter-conversion between an achiral CuII molecular square, and a 1D spontaneously resolved chiral interpenetrated double-chain with Cu4 cavities, based on bis(3-propionyloxy)-1,5-diazacyclooctane (H2L), has been successfully achieved.
Survey studies of pressure−temperature-induced transformations of single-wall carbon nanotubes (SWNT) at 1.5, 8.0, and 9.5 GPa and temperatures ranging from 200 to 1500 °C in a piston-cylinder or “Toroid” type high pressure devices have been carried out. It was found that the combined effects of high pressures and hig…
To study structural changes with changing chemical composition in the octahedral sheet of trioctahedral potassium-rich 1M micas, 3 natural and 12 synthetic micas were examined by singlecrystal X-ray diffraction. Samples with Ni 2+ , Mg 2+ , Co 2+ , Fe 2+ , and Al 3+ in the octahedral sheet and with Si 4+ , Al 3+ and o…
The reaction of the (101̄4) calcite surface during dissolution was studied as a function of pH (HCl) by liquid-cell Atomic Force Microscopy (AFM) under ambient conditions of both temperature (22 °C) and partial pressure of carbon dioxide (P CO2 ). A flow through AFM liquid reaction cell was used, and solutions were re…
Based on a biomimetic design, Si 3 N 4 /BN composites with laminated structures have been prepared and investigated through composition control and structure design. To further improve the mechanical properties of the composites, Si 3 N 4 matrix layers were reinforced by SiC whiskers and BN separating layers were modi…
An Anderson-type polyoxometalate, [IVIIMo6O24]5–, has been used as a catalyst for the aerobic oxidation at 80 °C of vicinal diols (glycols). This is the first report on the use of such a polyoxometalate as an oxidation catalyst. Reactivity and selectivity were dependent on the substrate. Thus, aryl-substituted diols y…
The amination of ketoacids to amino acids by pyridoxamine is greatly accelerated when the pyridoxamine is covalently linked to polyethylenimine carrying N-methyl and N-lauryl groups. Michaelis-Menten kinetics is seen with all substrates, from which the effect of the lauryl groups and the methyl groups can be determine…
This paper proposes a model of core-type distribution transformers for electromagnetic (EM) transient studies. The model accurately reproduces not only the impedance characteristics seen from each terminal of a core-type distribution transformer but also the surge-transfer characteristics between the primary and secon…
Breakdown theories yield a specified time to breakdown for fields exceeding a critical value, whereas experiment shows that times-to-breakdown and breakdown fields are different on a sample-to-sample basis. This has forced the use of a statistical approach to failure, often without a clear physical understanding of th…