Materials Literature
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The pore structure stability of MCM-41 materials upon hydration/dehydration was studied by XRD, 29 Si MAS NMR, and gravimetric adsorption techniques. Results demonstrated that collapses of the pore structure of MCM-41 occurred upon rehydration at room temperature due to the hydrolysis of the bare Si−O−Si(Al) bonds in…
Forty-two years ago, Johannes Georg Bednorz and Karl Alex M̈ller startled the world with their unexpected discovery of superconductivity in layered copper oxide perovskites at temperatures substantially higher than previously thought possible. The history of this breakthrough is well known, and a large number of relat…
Abstract Kinetic studies of the bulk polymerization of methyl methacrylate at high temperature have been carried out first without any additives and then in the presence of 1-Butanethiol as a chain transfer agent. A pressurised dilatometric reactor operating at high temperature is used to determine the time-conversion…
The biosynthetic threonine deaminase from Escherichia coli, an allosteric tetramer with key regulatory functions, has been crystallized in several crystal forms. Two distinct forms, both belonging to either space group P3121 or P3221, with different sized asymmetric units that both contain a tetramer, grow under ident…
Low‐stress mechanical properties of fabrics are very important in many applications as well as in manufacturing process control. Discusses the importance and potential applications of an on‐line mechanical property measurement system. In addition, the working principles of existing off‐ line fabric bending testers hav…
Transition metal (TM) fluoride electron beam sensitive resists suitable for the in situ fabrication of arbitrarily shaped nanometer scale magnetic structures have been developed. 20 nm thick TM fluoride films are prepared by thermal evaporation onto thin carbon films. Nanopatterns are written directly into the TM fluo…
Results of quantum chemical computer simulations of close Frenkel defects in corundum crystals are presented and discussed. The conclusion is drawn that the energy barrier for a back recombination up to fourth nearest neighbours is less than 0.3 eV, i.e. such pairs should be unstable at temperatures above 40 K.
In crystal optics the concept of the geometric phases can be demonstrated to the naked eye with comparatively simple apparatus. Pancharatnam's phase is described by an area on the Poincaré sphere which is enclosed by geodesic lines (great circles) while the concept of the Berry phase does not restrict the nature of th…
Desolvation kinetics of two indomethacin (IMC) solvates namely methanolate and tert−butyl alcohol (TBA) solvate were studied at 60–100 °C by isothermal thermogravimetric analysis. The solvates can transform to one of two true polymorphic forms, α or γ Solid-state desolvation of IMC predominantly proceeds by a nucleati…
John C. Briggs; Thinking of Biology: Biotic replacements—extinction or clade interaction?, BioScience, Volume 48, Issue 5, 1 May 1998, Pages 389–395, https://do
Irradiation effects of γ-rays on corrosion rates of type 304ULC stainless steel in 9×10−3 mol/m3 boiling nitric acid containing an ionic additive of multivalence elements of Ce(IV), Cr(VI) or Ru(III) were studied by measuring weight losses of specimens immersed under the 60Co γ-ray irradiation of 1 kC/(kg·h) (4MR/h).…
P-CVD/CVI is used to densify model pores and to fabricate Nicalon/SiC microcomposites with pyrocarbon or (PyC-SiC)/sub n/ multilayered interphases. The gaseous precursors are hydrocarbons (CH/sub 4/ or C/sub 3/H/sub 8/) for pyrocarbon and CH/sub 3/SiCl/sub 3/-H/sub 2/ for SiC. The best densification conditions for 60;…
Les procédés de filtration tangentielle sont actuellement reconnus comme des techniques de séparation de haute performance depuis le laboratoire jusqu'à la production industrielle. le cur de ces techniques est la membrane. Le présent travail a pour objectif de mettre au point des membranes en argile à bas prix de revi…
Poly(2-methoxy-4-vinylphenol), polyMVP, and poly[(sodium 4-styrenesulfonate)-co-(2-methoxy-4-vinylphenol)], poly(SSS/MVP), were synthesized by radical polymerization using Vazo-64 or tributylborane as initiator. Poly(3,4-dihydroxystyrene) and poly[(sodium 4-styrenesulfonate)-co-(3,4-dihydroxystyrene)] were obtained by…
We have studied the epitaxial growth of GaSe, a layered van der Waals material, on GaAs, a zinc-blende-structure semiconductor. This heterostructure exhibits a 6% lattice mismatch, and is a prototypical example of van der Waals epitaxy, where the weak van der Waals interaction allows the misfit to be accommodated with…
Mixed crystals of the composition Sr5−yEuy(PO4)3Cl1−xFx with 0 ≤ x ≤ 1 and 0 ≤ y ≤ 0.05 were prepared by solid state reaction. The crystal structure, optical properties at room temperature, and the emission spectra of the polycrystalline materials at liquid nitrogen temperature are investigated. The structure paramete…
A CuO–ZnO/Al 2 O 3 , catalyst sample was prepared by wet impregnation methods using Al(OH) 3 , zinc and copper nitrate solutions followed by drying at 110°C and calcination at 600°C. The nominal molar composition of the resulting material was calculated to be 0.25CuO · 0.03ZnO/Al 2 O 3 Samples of this solid were expos…
Unit‐cell parameters and the space group of a new phase of dicalcium silicate (Ca 2 SiO 4 ) were determined by using powder X‐ray diffractometry and selected‐area electron diffraction techniques. This phase could be synthesized via the dissociation of hydrothermally synthesized alpha‐Ca 2 (SiO 4 H)OH at temperatures o…
YMnO 3 thin films with Y/Mn ratios from 1.00/1.05 to 1.00/0.90 were prepared by dip‐coating from solution, in which starting materials were refluxed, and the effects of the Y/Mn ratio on the structure and dielectric properties of YMnO 3 thin films were investigated. XRD measurements indicated that the films with the Y…
Bi 2 Te 3- x Se x (0≦ x <1) polycrystalline solids are prepared by a hot press method and their thermoelectric properties are studied. The samples show the maximum value of Z = 2.3×10 -3 K -1 at x =0.22. The lattice thermal conductivity is smaller than that of a single crystal. The lattice constant and power factor…