Hydrothermally stable restructured mesoporous silica
Pure silica mesoporous materials that exhibit remarkable hydrothermal stability may be prepared by restructuring calcined MCM-41 via secondary synthesis involving extended recrystallisation.
Materials Literature
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Preparation, characterization and photocatalytic properties of singly and doubly titania-modified mesoporous silicate MCM-41 by varying titanium precursors
A series of titania-modified MCM-41 have been synthesized from varying three kinds of titanium precursors [Ti(OBun)4, Ti(OBun)3(acac), Ti(OBun)2(acac)2] respectively and mesoporous molecular sieve MCM-41, in which titania existed as single or double layers. The samples were characterized by powder X-ray diffraction (X…
Structure and properties of casting films blended with starch and waterborne polyurethane
A series of casting films blended from starch and waterborne polyurethane (STPU) in aqueous solution were prepared. The structure and properties of the films were investigated by infrared spectroscopy, ultraviolet spectroscopy, scanning electron micrography, strength test, thermogravimetric analysis, and different sca…
A simple, novel method for the preparation of polymer-tetherable, zwitterionic merocyanine NLO-chromophores
A suite of polymer-ready nonlinear optical merocyanines has been synthesised and characterised. The tethering functionality—a vicinal dihydroxypropyl residue—is introduced onto the donor nitrogen of the chromophore precursor without the need for protection/deprotection steps, thereby giving ready access to potentially…
Use the power of sonocrystallization for improved properties
High-intensity sound initiates nucleation and helps to control crystal size and habit to yield products that better meet users' specifications.
Platinum colloids stabilized by bifunctional ligands: self-organization and connection to gold
Platinum nanoparticles accomodating bifunctional thiolate ligands self-assemble into regular superstructures or organize around a large gold particle; the shape of the superstructures can be modulated by addition of water.
Porous Mullite Preforms via Fused Deposition
Nonrandom porous mullite ceramic preforms were fabricated by the indirect fused deposition process. MgO was added to commercial mullite powders as a sintering aid. The influence of porosity and the amount of MgO on the densification and mechanical properties was studied. The shrinkage and compressive strength of the p…
XPS characterisation of catalysts during production of multiwalled carbon nanotubes
Characterisation of alumina supported catalysts was performed by TEM and XPS spectroscopy during formation of multiwalled carbon nanotubes from acetylene at 1000 K. TEM images showed that thick carbon fibres (outer diameter is around 20–40 nm) were generated on Fe/Al2O3 and Co/Al2O3 samples. The only sample producing…
Diffusion coefficient of hydrogen in α-phase palladium and palladium–platinum alloy
Diffusion of hydrogen in the α-phase Pd– and Pd81Pt19–H systems was investigated at 298 K by electrochemical methods in an aqueous solution of H2SO4. Smooth or Pd-black covered specimens were used. The concentration of hydrogen in the metal matrix was gradually increased by control of the electrode potential; equilibr…
Partition Coefficients and the Free Energy of Confinement from Simulations of Nonideal Polymer Systems
The investigation of the partitioning equilibrium in real polymer systems by Monte Carlo (MC) simulations is reported. In contrast to ideal chain treatments the factors such as flexibility and excluded volume in real chains, the finite concentration of macromolecules φ, and polymer adsorption on pore walls of the attr…
Investigation of porphyrin-forming reactions. Part 1. Pyrrole + aldehyde oligomerization in two-step, one-flask syntheses of meso-substituted porphyrins †
A deep understanding of the two-step, one-flask synthesis of meso-substituted porphyrins requires characterization of the acyclic oligomers, which typically constitute ≥50% of the products. We have employed laser desorption mass spectrometry (LD-MS) to obtain a qualitative yet high resolution view of the oligomer cont…
Equiaxed Solidification of Steel Nucleating on Titanium Nitride
Equiaxed solidification of steel was investigated with emphasis on the nucleation on titanium nitride (TiN). Ferritic stainless steels bearing different amounts of titanium and nitrogen were remelted using a gas-tungsten-arc welding, and equiaxed grain formation was examined in the as-solidified welds. It was found th…
Preparation and Properties of Hydrothermally Stable γ‐Alumina Membranes
Supported mesoporous γ‐Al 2 O 3 membranes deteriorate and blister in steam‐containing environments at high temperatures. This deterioration led us to the development of a new type of supported γ‐Al 2 O 3 membrane with significantly improved stability under hostile conditions. Two measures were taken to achieve this re…
Dissecting a Charged Network at the Active Site of Orotidine-5′-phosphate Decarboxylase
The crystal structure of yeast orotidine-5'-phosphate decarboxylase in complex with the postulated transition state analog, 6-hydroxyuridine-5'-phosphate, reveals contacts between this inhibitor and a novel quartet of charged residues (Lys-59, Asp-91, Lys-93, and Asp-96) within the active site. The structure also sugg…
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.
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…