Materials Literature
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Bio- and chemical sensing, biomaterials, and in vivo electronics are some of the latest advances for porous silicon (p-Si) discussed in this review. p-Si is extremely versatile owing largely to its well-known luminescence properties (the Figure shows photoluminescence from patterned p-Si), high surface area, and facil…
Hundreds of acetyltransferases exist. All use a common acetyl donor--acetyl coenzyme A--and each exhibits remarkable specificity for acetyl acceptors, which include small molecules and proteins. Analysis of the primary sequences of these enzymes indicates that they can be sorted into several superfamilies. This review…
Techniques and methods to facilitate the solution of structures by simulated annealing have been developed from the starting point of a space group and lattice parameters. The simulated-annealing control parameters have been systematically investigated and optimum values characterized and determined. Most significant…
Polymers filled with low amounts of layered silicate dispersed at nanoscale level are most promising materials characterized by a combination of chemical, physical and mechanical properties that cannot be obtained with macro- or microscopic dispersions of inorganic fillers. Polymer layered silicate nanocomposites can…
Ordered nanoporous films have been generated via selective degradation of self-assembled block copolymer films of polystyrene (PS) and poly(methylmethacrylate) (PMMA), which contain oriented cylindrical microdomains. Deep UV irradiation degrades the PMMA, which can be rinsed away, leaving an ordered array of circular…
Functionalizing the termini of low-molecular-weight telechelic polymers with strongly associating hydrogen bonding units (see Figure) results in a new set of supramolecular materials, as reported here. These materials possess the unique combination of polymer-like properties at room temperature and monomer-like proper…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTStrong Luminescence of Solubilized Carbon NanotubesJason E. Riggs, Zhixin Guo, David L. Carroll, and Ya-Ping SunView Author Information Department of Chemistry and Center for Advanced Engineering Fibers and Films Howard L. Hunter Chemistry Laboratory Department of Phys…
Abstract Summary: DaliLite is a program for pairwise structure comparison and for structure database searching. It is a standalone version of the search engine of the popular Dali server. A web interface is provided to view the results, multiple alignments and 3D superimpositions of structures. Availability: DaliLite…
The majority of soluble and membrane-bound proteins in modern cells are symmetrical oligomeric complexes with two or more subunits. The evolutionary selection of symmetrical oligomeric complexes is driven by functional, genetic, and physicochemical needs. Large proteins are selected for specific morphological function…
Ferromagnetism of ZnO-based magnetic semiconductors was investigated by ab initio calculations based on the local density approximation. In a system of Mn atom doped ZnO, the ferromagnetic ordering of Mn magnetic moments was induced by hole doping. It was also found that 3 d transition metal atoms of V, Cr, Fe, Co and…
As the sizes of electronic and mechanical devices are decreased to the micron and nanometre level, it becomes particularly important to predict the thermal transport properties of the components. Using molecular level theories, such predictions are particularly important for modelling nano-electronic devices where sca…
The characterization of native point defects in ZnO is still a question of debate. For example, experimental evidence for ZnO with an excess of Zn is inconclusive as to whether the dominant defects are metal interstitials or oxygen vacancies. This information is essential to understand the behavior of the material and…
We report a comprehensive spectroscopic study of KY 3 F 10 doped with trivalent praseodymium. Employing both infrared absorption and laser excited fluorescence spectroscopy, we have constructed an energy level scheme of 39 crystal-field states. A C 4v symmetry, conventional crystal-field analysis can well account for…
Measurements of the complex elastic Young's modulus of PZT ceramics as a function of the frequency of a triangular switching electric field and of an ac dynamic mechanical stress were performed. The results show that the electrostrictive character of the ceramics provides a complex elastic Young's modulus, which depen…
We have measured the inelastic neutron scattering spectra of the glasses of six mono- and polyalcohols; 1-propanol, ethylene glycol, propylene glycol, 1,3-propanediol, glycerol and threitol. Broad excitation peaks with peak top energy of 3-5 meV appeared in all of the S (2θ, E ) spectra. These peaks were identified as…
4,4'-Bis(N-tert-butyloxylamino)-2,2'-bipyridine (4) and its 1:1 complexes with bis(hexafluoroacetylacetonato)manganese(II), -copper(II), and -zinc(II) were prepared. An X-ray structure analysis of free ligand 4 reveals that the molecule has a trans conformation with Ci symmetry and the aminoxyl radical center has a sh…
Crystal structures of human and rabbit cytosolic serine hydroxymethyltransferase have shown that Tyr65 is likely to be a key residue in the mechanism of the enzyme. In the ternary complex of Escherichia coli serine hydroxymethyltransferase with glycine and 5-formyltetrahydrofolate, the hydroxyl of Tyr65 is one of four…
α-decay damage and recrystallization in natural zircon (with dose ranging from 0.06 to 23.3 × 10 18 α-events g -1 ) were studied using polarized reflection infrared spectroscopy. The experimental results show that α-decay damage leads to a gradual decrease in reflectivity and a loss of anisotropy of IR spectra. Recrys…
Three conjugated polymers containing oligothiophene units (from one to three thiophene rings) and aromatic 1,3,4-oxadiazole moieties have been successfully synthesized. The polymer structures were characterized and confirmed by (1)H and (13)C NMR, FT-IR, and elemental analysis. Thermogravimetric analysis demonstrated…
The formation of cristobalite and tridymite compounds is described in the system SiO 2 -V 2 O 5 -M 2 CO 3 (M = Na, K). Syntheses were performed with various vanadium concentrations at annealing temperatures between room temperature and 1000°C. Crystallization of cristobalite occurs at much lower temperatures (about 80…