Materials Literature
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Coupling agents in wood fiber and polymer composites (WFPC) play a very important role in improving the compatibility and adhesion between polar wood fibers and non-polar polymeric matrices. In this paper, we review coupling agents, pretrcatment, and mixing technology for wood fiber and polymer currently used in the m…
The aggregation of nanocrystals has long been believed to result in disordered solids. In his Perspective, Alivisatos discusses recent evidence that nanocrystals may also form oriented assemblies. He highlights the work by Banfield et al. in this issue, who show that such alignment can also occur in natural systems. T…
The radiation performance of a variety of complex oxides is predicted on the basis of a material's propensity to accommodate lattice point defects. The calculations indicate that a particular class of oxides possessing the fluorite crystal structure should accept radiation-induced defects into their lattices far more…
Particles in the nanometer size range are attracting increasing attention with the growth of interest in nanotechnological disciplines. Nanoparticles display fascinating electronic and optical properties as a consequence of their dimensions and they may be easily synthesized from a wide range of materials. The dimensi…
Certain biopolymers, such as DNA, have a double-stranded twisted structure and frequently exhibit a supercoiled conformation. Over the past decade, extensive conformational analyses of different biopolymers have been performed using atomic force microscopy. In this technique, a necessary step in sample preparation is…
The total vapor pressures of cerium trihalides CeCl 3, CeBr 3, and CeI 3 were measured by the torsion method, and their temperature dependence can be expressed by the following equations over the given temperature ranges: CeCl 3 (s), log( p /kPa) = (12.21 ± 0.20) − (16443 ± 150)K/ T, (955−1070) K; CeBr 3 (s), log( p /…
The poly(3-hydroxybutyrate) (PHB) synthase of Ralstonia eutropha, which was produced by a recombinant strain of Escherichia coli and purified in one step with a methyl-HIC column to a purity of more than 90%, was used to polymerize 3-hydroxypropionyl-CoA (3HPCoA) and to copolymerize 3HPCoA with 3-hydroxybutyryl-CoA (3…
Enzymatic copolymerization of lactones, divinyl esters, and glycols has been performed using lipase as catalyst to produce ester copolymers. The monomers used in this study were 12-, 13-, and 16-membered lactones, divinyl esters of adipic and sebasic acids, and alpha,omega-glycols. Candida antarctica and Pseudomonas c…
Triblock copolymer micelles have been used successfully as templates to form porous, highly uniform, and hollow MoO 3 nanospheres, with their diameter being equivalent to the micellar core size. By use of a combination of static and dynamic light scattering, small-angle X-ray scattering, and wide-angle X-ray diffracti…
In previous studies of capillary condensation of water between mica surfaces using the surface force apparatus (SFA) it has not been possible to obtain agreement with the Kelvin equation. The condensates in these studies exhibited refractive index values larger than that of bulk water and often deposited residues of i…
Organized mesoporous silica (OMS) constitutes new materials with many potential applications. These materials with very well organized pores can be obtained by lowering the pH of precursor systems, i.e., highly alkaline silicate solutions containing cationic surfactants such as cetyltrimethylammonium bromide (CTAB) or…
Reduction of a chiral cerium bisporphyrinate double-decker complex Ce(MOFPP) 2 (MOFPP = 5,15-bis(3,5-dimethoxyphenyl)- 10,20-bis(pentafluorophenyl)porphyrin dianion) with sodium anthracenide in dioxane at 20 °C resulted in acceleration of the porphyrin ligand rotation (= racemization) by a factor of more than 300. Pho…
Graphite, oxidized by HNO 3 and NaClO 3 to 25% (GO-25), 42% (GO-42), and 33% (GO-33), has been dispersed to partially exfoliated nanoplatelets and, along with poly(diallyldimethylammonium chloride) (PDDA) and poly(ethylene oxide) (PEO), layer-by-layer self-assembled to ultrathin S−(PDDA/GO) 10, S−PDDA/(GO/PEO) 10, and…
Nanocrystals or quantum dots of the IV-VI semiconductors PbS, PbSe, and PbTe provide unique properties for investigating the effects of strong confinement on electrons and phonons. The degree of confinement of charge carriers can be many times stronger than in most II-VI and III-V semiconductors, and lead salt nanostr…
The spin-state transition is an interesting and unresolved problem in layered perovskite La 2- x Sr x CoO 4 under doping, as it involves competition among different magnetic structures. Within the unrestricted Hartree-Fock approximation and using the real space recursion method we have studied the effect of Sr doping…
The crystal structure of chemically disordered lead scandium niobate, Pb(Sc 1/2 Nb 1/2 )O 3 , is studied by the high-resolution neutron powder diffraction method. The data, collected over the temperature range 2-653 K, are analysed using Rietveld refinement. From 653 K to 378 K, the symmetry of PSN is found to be cubi…
The crystal structure of DMABA has been determined at 293 and 180 K. It crystallizes in the monoclinic P 2 1 / c space group. The structure was refined to R 1 = 0.0466 for 1269 independent reflections at 293 K and R 1 = 0.038 for 1728 reflections at 180 K. DMABA is isomorphous with the chlorine analogue, DMACA. Its an…
We investigate the electron population dynamics in an ensemble of nearly isolated insulating nanoparticles, each nanoparticle modeled as an electronic two-level system coupled to a single vibrational mode. We find that at short times the ensemble-averaged excited-state population oscillates but has a decaying envelope…
Abstract The superplasticity exhibited by some fine-grained ceramics, notably 3-mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP), offers interesting possibilities to lower manufacturing costs by near net shape forming. Both glassy and crystalline materials have been added to pure 3 Y-TZP to limit grain…
The effect of niobium dopant and annealing (900°C, 8h) on the crystal structure, microstructure, and piezoelectric properties of 0.55Pb(Sc1/2Ta1/2)O3-0.45PbTiO3+xmass%Nb2O5 ceramics (Nb-doped PSTT) (x=1, 0.5%, 1.5%, 2%) were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and piezoelectric…