Preparation of Silicophosphate Alternating Hybrid Copolymers via Nonaqueous Acid-Base Reactions of Phosphoric Acid and Organo-Bridged Bis(chlorosilane).

A design of atomic and oligomer level structure in organic-inorganic hybrid materials is highly important for various applications. Nonaqueous acid-base reaction allows us to prepare silicophosphates with controlled inorganic networks (-(O-P-O-Si)) at atomic level because phosphorous and silicon-based precursors can react directly, resulting in an alternating copolymer network. Organic functionalization in those materials has been realized so far by using organic-modified phosphorous acid and/or organo-chlorosilane as precursors.

Removal of radioactive Cs from gravel conglomerate using water containing air bubbles.

Remediation of sites contaminated with radioactive material such as Cs is important because of the risk posed to human health. Here, we report the effectiveness of water containing air bubbles with a diameter around 100 nm (nanobubbled water, NB water) for the removal of radioactive Cs. Laboratory experiments confirmed that NB water is more effective than purified water and as effective as water with neutral detergent in the removal of Cs-137 from gravel.

Correlation between emission property and concentration of Sn2+ center in the SnO-ZnO-P2O5 glass.

The authors report on the correlation between the photoluminescence (PL) property and the SnO amount in SnO-ZnO-P2O5 (SZP) glass. In the PL excitation (PLE) spectra of the SZP glass containing Sn2+ emission center, two S1 states, one of which is strongly affected by SnO amount, are assumed to exist. The PLE band closely correlates with the optical band edge originating from Sn2+ species, and they both largely red-shifts with increasing amount of SnO.

White light emission of Mn-doped SnO-ZnO-P2O5 glass containing no rare earth cation.

The authors have demonstrated white light emission of rare earth (RE)-free Mn-doped SnO-ZnO-P(2)O(5) glass. The RE-free glass shows white light emission with a high value of quantum efficiency (QE) comparable to conventional crystalline phosphor. It is notable that the high QE value is attained for RE-free transparent glass, and the broad emission can be continuously tuned by both the amount of activator and the composition of the glass.

Effects of organic groups on structure and viscoelastic properties of organic-inorganic polysiloxane hybrid system.

The structure and viscoelastic properties of an organic-inorganic hybrid system composed of an organically modified polysiloxane network were examined, and the influence of organic groups on elastic-modulus variation by heat treatment was studied. The increase in the number of phenyl (Ph) groups per silicon decelerates the increase in elastic modulus; the substitution of the Ph group for a methyl (Me) group accelerates it. The system basically consists of R4-mSi[O-]m/2 units, where R is the organic group.

Template-free magnesium oxide hollow sphere inclusion in organic-inorganic hybrid films via sol-gel reaction.

Magnesium oxide hollow spheres without a template core were conveniently prepared by stabilized bubble formation in a hybrid solution containing a magnesium acetate precursor, thus avoiding the complicated preparation process using a template. The hollow sphere could be aligned along the radial striation by spin coating, and its diameter from a micrometer to submicrometer dimension could be easily modified by the solution composition. It was also possible to control the open or closed hollow sphere by changing the solvent.

Viscoelastic and structural properties of a phenyl-modified polysiloxane system with a three-dimensional structure.

The relationships between the viscoelastic and structural properties of glass-forming materials with polysiloxane bonds, which serve as network formers, and phenyl groups, which act as network terminators, are examined based on shear viscoelasticity, (29)Si MAS NMR, and GPC measurements during the early stages of the network-forming process. The viscosities of the present samples do not depend on the frequency at temperatures up to 200 degrees C, suggesting that the origin of the viscous flow does not include intermolecular entanglement. According to the results of the strain dependence of the elastic modulus, the bridging-oxygen number, and molecular weight, the present polysiloxane system has a complex structure, or distribution of various-sized molecules composed of a polysiloxane network with various dimensionalities, and furthermore an elementary process of the viscosity is simple flow of these molecules.

Photosensitive GeO2-SiO2 films for ultraviolet laser writing of channel waveguides and bragg gratings with Cr-loaded waveguide structure.

Irradiation with intense ultraviolet laser pulses induced a large refractive-index change in 30GeO2-70SiO2 waveguide-grade thin films prepared by the plasma-enhanced chemical vapor deposition method, which contained a large amount of photoactive Ge2+ defects. The maximum index change in the as-deposited films by KrF and XeF excimer laser irradiation was estimated to be 1.2 x 10(-3) and 0.