Materials Literature
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Abstract The softening of the wood polymers is very important in the utilization of wood fiber products. To better to understand how the hemicelluloses interact with the other wood polymers in the fiber ultrastructure and contribute to the mechanical properties of the wood, their softening inside the cell wall of pulp…
The luminescence of synthetic rare earth (RE)-doped zircons and three natural zircons has been studied by ion beam excitation (ion beam luminescence or ionoluminescence (IL)). Luminescence results from electronic transitions between energy levels of the RE ions, giving emissions with characteristic energies. Studies o…
An essential property of combustion catalysts is long-term (>8000 h) stability at high temperatures in an environment (approximately 1 atm of both oxygen and water vapor) that aggressively promotes sintering of the supporting oxide and coarsening of the active component. Extrapolation of accelerated coarsening rate me…
Abstract In this article, the graft copolymerization of methyl methacrylate (MMA) onto sago starch (AGU) was carried out in aqueous medium using potassium persulfate (PPS) under nitrogen gas atmosphere. The maximum percentage of grafting achieved was 90% under optimized conditions of reaction temperature, monomer, PPS…
Abstract The presence of naphthalene, phenol and benzoic acid derivatives in natural waters constitutes a public health issue. The toxicity and chemical activity of these chemicals and their persistence in the environment depend on the types of functional groups attached to their basic aromatic structure. Surface‐enha…
Whereas tetrahydrofolate is an essential cofactor in all bacteria, the gene that encodes the enzyme dihydrofolate reductase (DHFR) could not be identified in many of the bacteria whose genomes have been entirely sequenced. In this communication we show that the halophilic archaea Halobacterium salinarum and Haloarcula…
The absorption of dyes within hydrogen-bonded and electrostatically assembled multilayers and subsequent release of the dyes from the films were studied in situ using FTIR-ATR. Multilayers were composed of poly(methacrylic acid), PMAA, and poly(ethylene oxide), PEO (hydrogen-bonded multilayers), or of PMAA and 22% qua…
Abstract Summary: New epoxy materials are needed with low dielectric constants ( Dk or ε r ), low loss ( Df or tan δ ) in the giga‐hertz frequency range and high glass transition temperatures ( T g s) for next generation fiber reinforced printed circuit boards. In this work, the incorporation of adamantane into an epo…
Abstract Ausgehend von den Ursachen, den Quellen des elektrochemischen Rauschens, wird an mehreren Beispielen die gute Korrelation zwischen verschiedenen Systemparametern und den Rauscherscheinungen gezeigt. Bei Beachtung einiger Randbedingungen bieten sich sehr gute Möglichkeiten, das Rauschen für eine Art Frühwarnsy…
The fundamental principle underlying the selective catalytic reduction (SCR) of NO x to N 2 is the promotion of reactions of reductant with NO x over competing, and thermodynamically preferred, reactions with a large excess of O 2 . A similar competition between NO x and O 2 exists in the noncatalytic, thermal reducti…
The behavior of ammonia absorption and desorption was studied for CaCl 2 −CaBr 2 halide mixtures with various molar ratios prepared via the aqueous solution method. The CaCl 2 −CaBr 2 halide mixture was revealed to form solid solutions in any molar contents. Ammonia absorption abruptly increased at some pressure, form…
A series of N-confused tetraphenylporphyrins (H(2)NCTPPs) with substituents on either the para- or the 3,5-positions of the meso phenyl rings were prepared using Lindsey conditions. Both electron-withdrawing and electron-donating groups were chosen in order to probe the effects of peripheral substitution on the proper…
The idea of combining the anisotropic behaviour of liquid crystalline materials with the properties of macromolecular systems was first suggested by Onsanger and subsequently Flory. The actual realization that such systems could exist came from studies of natural polymers such as the tobacco mosaic virus. Interest in…
Both zero-point and classical thermal effects on the chemical shift of transition metals have been calculated at appropriate levels of density functional theory for a number of complexes of titanium, vanadium, manganese and iron. The zero-point effects were computed by applying a perturbational approach, whereas class…
We propose an extension to the phenomenological thermodynamic Landau-Devonshire theory to include the contribution of inhomogeneous strains caused by lattice defects to the Gibbs free energy. The model yields correction terms for dielectric and ferroelectric quantities as a function of both elastic misfit strain and d…
Pressure-induced phase transitions in ${\mathrm{Eu}}_{2}{({\mathrm{MoO}}_{4})}_{3}$ single crystals were studied by fluorescence spectroscopy in the range of ambient pressure to $10\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. The spectral range investigated was limited to the $^{5}D_{0}\ensuremath{\rightarrow}^{7}F_{J}$,…
Abstract The role of rigid particle size in the deformation and fracture behavior of filled semicrystalline polymer was investigated with systems based on polypropylene (PP) and model rigid fillers [glass beads, Al(OH) 3 ]. The regularities of the influence of particle content and size on the microdeformation mechanis…
The methods of synthesis of new oxide compounds and thin-film materials based on the use of heteroepitaxy are considered. The thermodynamic model and the theory of the epitaxial stabilisation phenomenon are outlined, the role of thermodynamic and structure-geometric factors determining the possibility of epitaxial sta…
The variation with microwave frequency and temperature of previously reported anomalous peaks in the EPR spectra of ${\mathrm{Mn}}_{12}$-acetate, under large transverse fields, reveals that the molecular easy magnetization axes are tilted with respect to the global symmetry direction. More importantly, on the basis of…
[reaction: see text] Starting from diactylene diacarboxylic acids, we have synthesized a series of photopolymerizable organogelators that possess simple amide structures, different alkylene chain lengths, and either optically active or racemic 3,7-dimethyl-1-octylamine units. The alkylene chain length of these compoun…