Materials Literature
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Abstract A method for deriving kinetic equations of decomposition of thermally unstable chemicals from isothermal DSC experiments was developed. The following steps are included in the method: collecting experimental data in the form of heat flow versus time from isothermal DSC experiments at three or four different t…
X-ray-absorption fine-structure studies of the local structure of large Pb and Sn substitutional impurities in GeTe were carried out. The local environment of these atoms in ${\mathrm{Ge}}_{0.9}$${\mathrm{Pb}}_{0.1}$Te and ${\mathrm{Ge}}_{0.85}$${\mathrm{Sn}}_{0.15}$Te solid solutions was shown to be strongly distorte…
Summary The fine earth (<2 mm) and rock fragments (>2 mm) fractions of two soils derived from Oligocene sandstone have been examined to assess the origin of the discrepancies between cation exchange capacity (CEC) and effective CEC (ECEC). The soils differ in terms of acidity: soil A is more acid than soil B. Wh…
Cadmium sulfide (CdS) nanoparticles were prepared using the Aerosol-OT (AOT)/heptane inverse-micelle method. The particle size was controlled by changing the [H 2 O]/[AOT] ratio in the preparation process to be ca. 3 nm, which was estimated from their absorption maximum ( ca. 385 nm) and absorption edge ( ca. 450 nm)…
The thermoplastics processing of natural hydrophilic polymers in the presence of water is a recent development with very wide possible applications. Eventually, oil-based polymer materials could be replaced in many applications by inexpensive, natural products from renewable resources. As with conventional thermoplast…
The new compounds CsTaQ 3 (Q = S, Se, and Te) have been synthesized through stoichiometric reactions of the elements with Cs 2 Q n reactive fluxes at 923 K. Their crystal structures have been determined by single-crystal X-ray methods. CsTaQ 3 crystallize in the hexagonal space group − P 6 3 / mmc with two formula uni…
Abstract X-ray diffraction chlorite crystallinity (ChC) indices and major element chemical compositions of chlorites and bulk rocks were determined and correlated in meta-igneous rocks from different Mesozoic formations in various tectonic units of the Bükk Mountains, NE Hungary. The rocks, of basic to acidic composit…
The current status of photoelectron-diffraction studies of surface structures is briefly reviewed, and several recent developments and proposals for future areas of application are then discussed. The application of full-solid-angle diffraction data, together with simultaneous characterization by low-energy electron-d…
Triplet−triplet intramolecular energy transfer in a covalently linked copper(II) porphyrin−free base porphyrin hybrid dimer was examined by time-resolved (TR) ESR measurements of the lowest excited triplet (T 1 ) state of the free base porphyrin component after laser pulse excitation at 532 nm. The TRESR spectra of th…
The regeneration of LB films of (trimethylsilyl)cellulose (TMSC) ( 1 ) to ultrathin films of cellulose ( 2 ) is monitored by X-ray photoelectron spectroscopy (XPS). Subsequent chemical derivatization of these regenerated cellulose films with trifluoroacetic anhydride (TFAA) ( 3 ) to give the corresponding cellulose tr…
What exactly is an interface , and when is an interphase the more correct concept? The nature of interfaces and the phenomena occurring there are described before the role of interphases is illustrated with a series of examples taken from purely artificial systems (e.g., polymer and polymer‐metal “interfaces”) and nat…
From magnetic susceptibility measurements the J-value of (&mgr;-hydroxo)bis[pentaamminechromium(III)] chloride hydrate was found to be 32.3 cm(-)(1). The EPR spectra of the complex diluted in the analogous cobalt(III) complex have been recorded down to 4 K. The spectrum from the quintet state has been identified by th…
We have investigated the relationship between order parameter and physical constants (dielectric anisotropy and splay elastic constant) for fluorinated liquid crystals with a small temperature coefficient of the threshold voltage. In these special fluorinated liquid crystals, the dielectric anisotropy is proportional…
Organic nonlinear optical crystals have several advantages over inorganic crystals for frequency conversion and electro-optic modulation. In the present work, the effect of 100 MeV Ag14+ ion irradiation on the electrical and optical properties of organic nonlinear crystal para-hydroxy acetophenone (HAP) is investigate…
Abstract In this work a preliminary study on the viscoelastic behavior of polyolefinic foam sheets with different chemical (polyethylene and polypropylene) and cellular structure by means of Dynamical Mechanical Analysis (DMA), in the low frequency and low compression ranges, is presented. Differential Scanning Calori…
The reactivity of oxygen adatoms formed by dissociative adsorption of O 2 on Cu(100) at 100 K for CO oxidation and hydrogen abstraction from water was investigated by means of HREELS and TPD in comparison with the reactivity of adsorbed oxygen in thermally stable phases. The oxygen adatoms formed on the Cu(100) surfac…
Other| June 01, 1997 Octahedral versus tetrahedral coordination of Al in synthetic micas determined by XANES Annibale Mottana; Annibale Mottana Universita di Roma Tre, Dipartimento di Scienze Geologiche, Rome, Italy Search for other works by this author on: GSW Google Scholar Jean-Louis Robert; Jean-Louis Robert Searc…
Most methods of crystal structure prediction generate many trial structures. Because these may differ in choice of unit cell, it is not always immediately obvious whether or not two such structures are equivalent. A method to answer this question is described for the case where the asymmetric unit contains one molecul…
A detection system made with a silicon drift detector cooled by a Peltier element has been designed and tested. This system has been conceived to be implemented in electron probe microanalyzers for the x-ray microanalysis of the specimen. The good energy resolution of the detector, 155 eV full width at half-maximum at…
Operation of the planar-flow melt-spinning process in a regime where the wheelspeed is high relative to the (average) solidification rate is studied. A distinct solidification front occurs. An analysis based on the governing energy and momentum equations shows that heat transfer and solidification are only weakly coup…