Materials Literature
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We develope a theoretical model of first order resonant Raman scattering in spherical nanocrystals which includes excitonic effects. Using a matrix diagonalization technique, the exciton wavefunctions and energy states as a function of quantun dot radius are calculated. The Fröhlich interaction between excitons and op…
Layered double hydroxides (LDHs) of Mg with trivalent cations such as Al, Cr and Fe show two mass loss steps on heating; the low-temperature (25–250 °C) loss is due to dehydration and the high-temperature (250–450 °C) loss is due to decomposition. Both steps are reversible and the oxide residues obtained after calcina…
Non‐centrosymmetric arrangement of the chromophores is a prerequisite for non‐vanishing macroscopic second‐order nonlinear optical responses. It is shown that an acentric packing of a highly polarizable merocyanine dye, with optimized orientation for frequency conversions, can be induced by hydrogen‐bond‐directed self…
Thin films of polypyrrole (PPY) were deposited in-situ from aqueous polymerizing solutions of pyrrole onto the surface of various substrates. A relationship between the structure of the dopant ion, conductivity, and optical absorption in the near IR was observed. The changes in conductivity and spectra are related to…
The influence of fibre charge on fibre and paper properties was investigated using five industrially produced hardwood (Betula verrucosa) and five softwood (Pinus sylvestris) ECF and TCF bleached kraft pulps. All pulps had been dried before the experiments. The relationship between total charge and tensile strength of…
The effect of cavitating 22 kHz ultrasound on aqueous solutions of hydrogen peroxide-consuming enzymes, catalase and peroxidases, both plant (horseradish peroxidase) and animal (lactoperoxidase) was studied. Catalase did not undergo inactivation during sonication, whereas activity of peroxidases decreased with increas…
The walls of the mesoporous silicate MCM-41 can be functionalised with ferrocenyl end groups by reaction with an alkane solution of (1,1′-ferrocenediyl)dimethylsilane; the product is studied by solid-state NMR and EXAFS spectroscopies.
Abstract In this study it is shown that the antiferrodistortive phase transition in titanite, CaTiSiO In order to study the stepwise structural changes synchrotron radiation was used to collect X-ray diffraction data at 100 K, 295 K and 530 K on the 4-circle diffractometer at HASYLAB using a wavelength of 0.560(1) Å.…
Transfer of the recognition activity of a ferrocene ionophore to an electrode surface from the homogeneous phase has been successfully accomplished for the first time. The synthesis and electrochemical characterization of a new pyrrole‐substituted ferrocene crown ether are described, followed by the formation of the c…
Nanotubes of hexagonal boron nitride (h-BN) were discovered to be formed on amorphous boron (am-B) particles by annealing am-B in an h-BN crucible with metal Li. Furthermore, BN nanoballs of multi BN layers and a single BN layer were discovered.
The first hyperpolarizability, β, of one of the simplest heterocyclic pyridinium betaines, (1-pyridinio)benzimidazolate, was measured experimentally with the hyper-Rayleigh scattering technique and compared to the calculated values obtained by the semiempirical INDO/S and ab initio molecular orbital methods. Heterocyc…
Abstract Amino acids of differing hydrophobicity were tested as plasticizers in starch‐glycerol (4:1 weight ratio) blends and were compared to the more conventional plasticizers, urea, sucrose and ammonium chloride. In mechanical tests (tensile strength and percent elongation) on extruded ribbons containing up to 20 w…
A planar multi target sputtering approach was used to deposit self polarized PZT films on TiO2/Pt bottom electrodes for the use in thin film pyroelectric IR detector arrays. By using elevated substrate temperatures of about 450°C “in situ” growth of tetragonal PZT could be achieved. The films exhibited pyroelectric cu…
We present a generalization of dissipative particle dynamics that includes shear forces between particles. The new algorithm has the same structure as the (isothermal) smoothed particle dynamics algorithm, except that it conserves angular momentum and includes thermal fluctuations consistently with the principles of e…
Upon treating the corresponding oxalates with carbon disulfide (p CS2 =130 Torr) at a heating rate of 5 °C min -1 , it is shown that the cubic γ-phase of pure rare-earth sesquisulfides (γ-Ln 2 S 3 ) can be obtained at 800 °C from samarium to holmium (also yttrium) and at 1000 °C from neodymium to dysprosium. By workin…
Reaction of elemental manganese, antimony and selenium under mild solvothermal conditions yields the complex anion [Mn 4 (en) 9 (SbSe 4 ) 4 ] 4 - , the first example of a transition-metal complex with SbSe 4 3- anions acting as ligands; the anions are coordinated in a terminal position as well as a bridging ligand.
Hydrolysis and initial polycondensation processes in the Si(OEt) 4 (TEOS)–RSi(OEt) 3 –EtOH–water–HCl systems (R=Me, Ph) [TEOS:RSi(OEt) 3 :EtOH:water:HCl=1:1:24:x:y (x=12, 2/3; y=2×10 -3 , 4×10 -3 , 8×10 -2 )] have been investigated by using 29 Si NMR spectroscopy. For comparison, the alkoxysilanes [TEOS, MeSi(OEt) 3 (…
New cholesteric liquid crystals induced by intermolecular hydrogen bonding between 3-cholesteryloxycarbonylpropanoic acid (MCB) and 4-(4-alkoxybenzoyloxy)-4-stilbazoles (n SZ); between MCB and N -(4-pyridylmethylidiene)anilines (n -PMA) were prepared. Their liquid crystalline properties were investigated by DSC, polar…
A series of polythiaarene derivatives has been synthesised and their redox properties studied. The charge stabilizing effect of the aryl sulfide groups that surround the central aromatic core promotes nucleophilic substitution and markedly facilitates radical anion formation, leading to remarkably mild reduction poten…
In this, the last of three articles on the optical absorption of electrons in a half-filled Peierls-distorted chain, we address the dimerized extended Hubbard model in the limit of a large on-site interaction U. When the Hubbard interaction is large compared with both the bandwidth W and the nearest-neighbour interact…