Materials Literature
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To further investigate favorable effects of divalent cations on the formation of protein crystals, three complexes of Salmonella typhimurium histidine-binding protein were crystallized with varying concentrations of cadmium salts. For each of the three histidine-binding protein complexes, cadmium cations were found to…
Violation of Friedel's law in the non-systematic many-beam case has been used to determine the absolute orientation of crystals without center of symmetry in the transmission electron microscope. Microdiffraction patterns of thin (thickness < extinction distance) crystals with practically homogeneous thickness have be…
Zinc oxide films were deposited by CVD in air and nitrogen under atmospheric conditions using zinc acetate and zinc oxyacetate as the precursors. Factors for obtaining reproducible depositions were identified. The activation energies using zinc acetate as the precursor were ∼ 45 kJ mol–1 (±20%) both in air and in nitr…
Composites are an important class of optical materials for use in nonlinear optics. Among them, layered materials are very interesting. In the present paper we describe optical linear and nonlinear properties of layered materials which follow a suitable process to realize a self-similar or fractal structure.
The tensile strength of α‐Si 3 N 4 whiskers synthesized by reacting amorphous Si 3 N 4 and TiO 2 at 1490°C under a N 2 pressure of 700 torr was measured using a microbalance, and the diameter dependence of the strength was investigated. The Si 3 N 4 whiskers had diameters of 0.04 and 0.8 μm and dominant [1011] and [10…
Birefringence (B(f)), refractive indices, and their temperature derivatives (dB(f)/dT) determine the temperature characteristics of nonlinear-optical laser devices. The birefringences at different temperatures are analyzed critically by use of a new physically meaningful Sellmeier equation for what is to the author's…
Copper bicrystals with isoaxial [1̄49] twist boundaries and a (1̄49)/(001) “random” boundary were notched at the interface, left or right regarding the slip geometry, and intergranular cracks were propagated under strain control, to study how dislocation structure, crystallography and strain localization affect crack…
The porosity-modulation technique has been applied to improve the emission properties of the previously reported surface-emitting cold cathodes based on electroluminescent porous silicon (PS) diodes. It is demonstrated here that by introducing a modified structure into the PS layer, the emission efficiency is signific…
The tensile mechanical behavior of an epoxy/amine system, with varying amounts of hardener, was evaluated. The results showed that a brittle to ductile transition occurs as the amount of hardener is increased. This behavior was associated with the change in the number of molecular segments that present mobility in the…
Abstract Main structural subdivisions of sulphate minerals and synthetic compounds were considered in the frame of a new structural classification of minerals, based on the strength distribution and directional character of the bonds. The specific features of their crystal chemistry were expressed by the corresponding…
A phase diagram based on dielectric‐permittivity‐versus‐temperature measurements and high‐temperature X‐ray diffractometry was proposed for 0.4Pb(Ni 1/3 ,Nb 1/3 )O 3 ‐ x PbZrO 3 ‐(0.6‐ x )PbTiO 3 (0.2 lessthan equal to x lessthan equal to 0.32) relaxor‐ferroelectric solid solution, and a morphotropic phase boundary th…
The phase behavior of pentylcyanobiphenyl (5CB) and octylcyanobiphenyl (8CB) liquid crystals confined to controlled porous glass of different characteristic void sizes $R$ is studied using deuteron NMR. In samples with the 5CB liquid crystal the discontinuous isotropic-nematic $(I\ensuremath{-}N)$ transition becomes g…
In situ Raman spectra of were recorded using a specially constructed spectroelectrochemical cell. A 1 M solution of in propylene carbonate‐dimethyl carbonate was used as the electrolyte and lithium foil as the anode. Three phases, γ', γ, and , are observed with increasing lithium content. The evolution of the Raman sp…
A series of flexible polyurethane slabstock foam samples were prepared with varying water content and studied using transmission electron microscopy (TEM), video-enhanced optical microscopy (VEM), and small-angle X-ray scattering (SAXS). A new TEM sample preparation technique was developed in which the foam is impregn…
All articles of this category pyrroles - formylation - pyrrole-2,5-dicarbaldehydes
The host-associated luminescence of highly dense transparent YAG ceramic material is characterized and compared to that of a single crystal. The UV emission from the ceramic shows a red shift of almost 100 nm from its position in the single crystal, along with major differences in excitation spectrum. The disparities…
An experimental investigation has been conducted to reduce NOx from combustion flue gases by means of corona discharge activated methane radical injection methods. Two types of corona radical injectors, the hollow needle type and the multihole type, are used in the present investigations. Experiments are conducted for…
Monolithic polymer-derived Si–C–N ceramics were processed by blending 70 vol% of both crosslinked and pyrolyzed Si–C–N powder particles with an oligomeric Si–C–N precursor (liquid polysilazane). The respective Si–C–N powder particles were prepared from the same liquid precursor, however, pre-heated at 300 and 1000 °C.…
We study the crack patterns produced by thermal shock in ceramic tableware. Cracks produced at sufficiently high-temperature gradients partition the surface plane of a ceramic material into cells forming a random two-dimensional space-filling cellular structure. The topological and geometrical properties of these stru…
There has been enormous interest in preparing the superhard material ${\mathrm{C}}_{3}{\mathrm{N}}_{4}$, with the large nitrogen concentration being one factor limiting preparation. Using an ab initio supercell approach we simulate the electronic structure about a N vacancy and investigate the effect it has on the bul…