A space group assignment of ZrP2O7 obtained by 31P solid state NMR
2-D 31P dipolar recoupling magic angle spinning NMR has been used to determine the true symmetry of the low temperature structure of ZrP2O7 for the first time.
Materials Literature
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Curing Reaction and Phase Change in a Liquid Crystalline Monomer
An epoxy monomer was cured in liquid crystalline phase with three different amines to form (LCT). The thermal transitions of the LCT were studied by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarized optical microscopy (POM). Different curing features are observed depending on t…
Interfacial contributions in lignocellulosic fiber-reinforced polyurethane composites
Whereas lignocellulosic fibers have received considerable attention as a reinforcing agent in thermoplastic composites, their applicability to reactive polymer systems remains of considerable interest. The hydroxyl-rich nature of natural lignocellulosic fibers suggests that they are particularly useful in thermosettin…
Morphological Effects on the Electrical and Electrochemical Properties of Carbon Aerogels
Carbon aerogels are prepared by a sol-gel process. By controlling the mass ratio of reactants and the molar ratio of resorcinol to catalyst (R/C), carbon aerogels with different microstructures can be developed. The electrical conductivity is measured by the van der Pauw method. The results show that the electrical co…
Tripyrrin—the missing link in the series of oligopyrrolic ligands
The first derivative of the hitherto elusive tripyrrin 2 was prepared and characterized; the X-ray structural analysis of its trifluoracetato-palladium(II) complex 7 displays a highly flexible N3 ligand.
Dynamics of extracellular matrix production and turnover in tissue engineered cardiovascular structures
Appropriate matrix formation, turnover and remodeling in tissue-engineered small diameter vascular conduits are crucial requirements for their long-term patency and function. This complex process requires the deposition and accumulation of extracellular matrix molecules as well as the remodeling of this extracellular…
Synthesis of Gd[sub 1−x]Eu[sub x]Al[sub 3](BO[sub 3])[sub 4] (0<x≤1) and Its Photoluminescence Properties under UV and Vacuum Ultraviolet Regions
Single phase europium-activated gadolinium aluminum borate, was obtained by the evaporation of its nitrate solution, and calcination at 900 to 1100°C in air. All the solid solution was identified as the isomorphs of huntite. activated showed intense red emission with CIE chromaticity coordinates of (0.645, 0.330) unde…
Interfacial adhesion of copper-low k interconnects
Adhesion energies of Cu-low k dielectric interfaces, measured with the technique of four-point bending, show a correlation to chemical mechanical polish results. A limit of 5 J/m/sup 2/ is established, below which thin film delamination and cracking are observed. In general, spin-on polymer dielectrics exhibit better…
Solvothermal synthesis of tantalum(V) oxide nanoparticles and their photocatalytic activities in aqueous suspension systems
Tantalum(V) oxide (Ta2O5) powders were synthesized by a solvothermal reaction of tantalum pentabutoxide (TPB) in toluene at 473–573 K in the presence of water. Ta2O5 powder with a large surface area (>200 m2 g−1) was obtained at 473 and 523 K, and its X-ray diffraction patterns showed no clear peaks of crystallites, w…
Reversible trans–cis photoisomerization of azobenzene-attached bipyridine ligands coordinated to cobalt using a single UV light source and the Co(iii)/Co(ii) redox change
The trans/cis ratio of the azobenzene-attached bipyridine ligands in a cobalt complex is reversibly altered by a combination of photoirradiation with a single UV light source and the reversible redox change between Co(II) and Co(III).
Photochromism of spirobenzopyranindolines and spironaphthopyranindolines
The photocolouration of five spiro[2H-1-benzopyran-2,2′-indoline] compounds (1–5) and two spironaphthopyranindolines (6, 7) to give the ring-opened merocyanine(s) and the subsequent thermal relaxation back to the closed form was studied. A trans-merocyanine but no cis-photoisomer were detected for 1–7 using λexc = 308…
Dislocation Loop Formation in Nonstoichiometric (Ba,Ca)TiO 3 and BaTiO 3 Ceramics
Dislocation loops observed in nonstoichiometric and stoichiometric (Ba,Ca)TiO 3 , and in stoichiometric BaTiO 3 sintered in a reducing atmosphere, were characterized by conventional transmission electron microscopy (TEM) under two‐beam conditions and high‐resolution TEM atomic structure analysis. Dislocation loops mos…
Synthesis of gold-decorated latexes via conducting polymer redox templates
The efficient electroless deposition of gold from aqueous solutions has been achieved via redox interaction between Au(III) ions and conducting polymers such polypyrrole, polyaniline and poly(3,4-ethylenedioxythiophene). When using the doped, conductive bulk powder forms of these polymers, the average size of the gold…
Effects of Photo-Controlled Nanophase Segregation in a Re-entrant Nematic Liquid Crystal
Liquid crystals composed of photoactive groups, such as azobenzene, are promising materials for optical switching and image storage applications. On exposure to light LC materials commonly undergo an order-to disorder transition. Here, an unusual disorder-to-order transition is presented (the Figure shows a photo-indu…
Synthesis and characterization of aragonite whiskers by a novel and simple route
A novel and simple synthetic method for the preparation of aragonite whiskers has been developed, whereby aqueous solutions of CaCl2 and Na2CO3 are combined in the presence of a suitable surfactant, poly(ethylene glycol)-20 000 (abbreviated as PEG), under ambient reaction conditions. The whiskers have high aspect rati…
Strain-induced crystallization and strength of elastomers. I.cis-1,4-polybutadiene
Crosslinked samples of cis-1,4-polybutadiene (BR) were crystallized at low temperatures and then slowly melted. From volume changes and differential scanning calorimetry measurements, the degree of crystallization in the unstrained state was estimated to be about 20%, much lower than for natural rubber (NR). Crystalli…
Gadolinium DO3A derivatives mimicking phospholipids; preparation and in vitro evaluation as pH responsive MRI contrast agents
A series of Gd-DO3A derivatives (8a–d) mimicking phospholipids have been prepared. Two of the complexes, Gd-HADB-DO3A (8a) and Gd-HADO-DO3A (8b), have been evaluated as pH responsive MRI contrast agents in vitro. The T1-relaxivity (r1) of Gd-HADO-DO3A (8b) increased 142% on changing the pH from 6 to 8. The pH dependen…
Solubility, Diffusivity, and Retrograde Vitrification in PMMA—CO 2 , and Development of Sub-micron Cellular Structures
A magnetic suspension balance was used to measure solubility of CO 2 in PMMA in the temperature range 0 to 167 ° C and at pressures to 61.2 atm. CO 2 dissolves to considerable extent in PMMA, reaching a value of about 30 wt% at 0 ° C and 34 atm. Diffusion coefficients, derived from the sorption kinetics, were analyzed…
Properties of CdO Thin Films Produced by Chemical Vapor Deposition
The properties of CdO films formed by low-pressure chemical vapor deposition were investigated as a function of deposition temperatures from 150-450°C. Atomic force microscopy, X-ray diffraction, and transmission electron microscopy revealed that the grain size, bulk crystallinity, and intragrain quality all improved…
Structural and Mössbauer study of Sr2FeO3X (X = F, Cl, Br) and the magnetic structure of Sr2FeO3F
The structures of Sr2FeO3F, Sr2FeO3Cl and Sr2FeO3Br have been investigated using powder neutron diffraction (PND). All three ferrates crystallise in the primitive tetragonal space group P4/nmm and the anions are fully ordered giving iron oxygen square pyramids separated by rock salt type layers of strontium halide. 57…