Einfluss der Werkstoffzusammensetzung auf die Luftschallemission beim Trennschleifen von Beton

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Crystal structure of sodium gallium germanium oxide, NaGaGeO4

GaGeNaO4, monoclinic, P2(1)/n (no. 14), a = 8.8794(5) angstrom, b = 8.2679(5) angstrom, c = 15.5969(9) angstrom, beta = 90.129(5)degrees, V = 1144.20 angstrom(3), Z = 12, R(I) = 0.013, R(P) = 0.056, T = 293 K

Symmetry reduction due to gallium substitution in the garnet Li6.43(2)Ga0.52(3)La2.67(4)Zr2O12

Single-crystal structure refinements on lithium lanthanum zirconate (LLZO; Li7La3Zr2O12) substituted with gallium were successfully carried out in the cubic symmetry space group I [Formula: see text]3d. Gallium was found on two lithium sites as well as on the lanthanum position. Due to the structural distortion of the resulting Li6.43(2)Ga0.52(3)La2.67(4)Zr2O12 (Ga-LLZO) single crystals, a reduction of the LLZO cubic garnet symmetry from Ia[Formula: see text] d to I [Formula: see text]3d was necessary, which could hardly be analysed from X-ray powder diffraction data.DFG/TMG/GE1981/31DFG/TMG/GE1981/32Niedersächsisches Ministerium für Wissenschaft und Kultur (MWK)/PH/74ZN99

Brookite versus anatase TiO2 photocatalysts: Phase transformations and photocatalytic activities

Titanium dioxide nanoparticles consisting of pure anatase, anatase-rich, brookite-rich, and pure brookite modifications were synthesized and characterized by X-ray diffraction, field emission-scanning electron microscopy and nitrogen adsorption. The phase transformations among the three modifications of TiO2 (anatase, brookite, and rutile) and the photocatalytic activities of these nanoparticles were investigated by heat treatment over the temperature range from 400 to 800 °C and by the photooxidation of methanol, respectively. Direct transformation of anatase and brookite to rutile was observed, while in the case of the anatase–brookite mixture, anatase transforms firstly to brookite and then to rutile. The photocatalytic activity measurements indicate that brookite nanoparticles exhibit higher photocatalytic activities than anatase, and a comparable activity to that of the anatase-rich nanoparticles. The phase transformations and photocatalytic results are discussed regarding their dependence on crystallite size, surface area, and phase composition

Evaluating carbon dots as electron mediators in photochemical and photocatalytic processes of NiFe2O4

Spinel ferrites such as nickel ferrite are promising energy conversion photocatalysts as they are visible-light absorbers, chemically stable, earth abundant, and inexpensive. Nickel ferrite shows poor photocatalytic activity due to fast electron-hole recombination upon illumination. This study evaluates the capability of carbon dots (CDs) to improve charge-carrier separation in NiFe2O4. We report a facile solvothermal approach for synthesizing NiFe2O4 and CDs/NiFe2O4 nanoparticles at 200-215 °C. The photocatalysts were characterized using transmission and scanning electron microscopy, x-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, UV-VIS-NIR spectroscopy, photoelectrochemical analysis, and laser flash photolysis. Photocatalytic oxidation of methanol to formaldehyde under visible light was employed to test the effect of CDs on the photocatalytic efficacy of NiFe2O4. UV-VIS-NIR spectroscopy depicted a total quenching of NIR absorption and a diminished absorption of a peak at ∼745 nm in CDs/NiFe2O4 compared with NiFe2O4, indicating a transfer of electrons from NiFe2O4 to CDs. A 12-fold increment in the incident-photon-to-charge-efficiency was achievable with CDs/NiFe2O4 (0.36%) compared with NiFe2O4 (0.03%). Impedance spectroscopy exhibited a more efficient charge separation and faster interfacial charge transfer in CDs/NiFe2O4 compared with pure NiFe2O4. This was accounted for by the lower initial quantity of charge carrier upon irradiation in CDs/NiFe2O4 compared with NiFe2O4 as detected from laser flash photolysis, indicating that CDs acted as electron acceptors and reservoirs in CDs/NiFe2O4. Compared with NiFe2O4, CDs/NiFe2O4 showed an enhanced photocatalytic activity toward formaldehyde formation. Consequently, CDs are good electron mediators for NiFe2O4, capable of improving charge-carrier separation and the photocatalytic activity of NiFe2O4

Increasing the Brønsted acidity of Ph2PO2H by the Lewis acid B(C6F5)3. Formation of an eight-membered boraphosphinate ring [Ph2POB(C6F5)2O]2

The Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged for financial support. The theoretical part of this work was supported by the Russian Science Foundation (Project 14-13-00832).Autoprotolysis of the metastable acid (C6F5)3BOPPh2OH, prepared in situ by the reaction of the rather weak Brønsted acid Ph2PO2H with the strong Lewis acid B(C6F5)3, gave rise to the formation of the eight-membered ring [Ph2POB(C6F5)2O]2 and C6F5H. The conjugate base was isolated as stable sodium crown ether salt [Na(15-crown-5)][Ph2PO2B(C6F5)3].Publisher PDFPeer reviewe

Report on Investigations to Examine LENR with CGDE

This paper is motivated by wish to witness LENR (Low Energy Nuclear Reaction) effect and to develop a step-by-step guide on how to build a basic LENR observation demonstrator, to introduce this topic to wider scientific discussion. The CGDE (Contact Glow Discharge Electrolysis) process is chosen to be used as the experimental means to investigate the feasibility of the LENR process

Dinuclear Face-Sharing Bi-octahedral Tungsten(VI) Core and Unusual Thermal Behavior in Complex Th Tungstates

Two new thorium tungstates A6Th6(WO4)14O (A=K and Rb) were synthesized by high-temperature solid-state reactions. The structures of both phases are based on a rare dinuclear confacial bi-octahedral [W2O9]6− core, encapsulated in a [Th6W7O46(W2O9)]32− cage showing a cross-section geometry similar to a six-leafed lily. The adjacent cages are connected in two dimensional layers by WO4 tetrahedral linkers. Due to the dissimilarities in mutual orientations of adjacent layers in these two structures, K6Th6(WO4)14O crystallizes in space group of R32 while Rb6Th6(WO4)14O stabilizes in Pequation image2c. The high-temperature phase transition was observed in Rb6Th6(WO4)14O and investigated using high-temperature PXRD technique. The results demonstrate a very unusual thermal behavior of this compound. The Raman and IR spectra of both phases were analyzed with respect to their complex structures

Disordered but primitive gallosilicate hydro-sodalite: Structure and thermal behaviour of a framework with novel cation distribution

The structure of a new gallosilicate sodalite |Na6.16(1)(H2O)8|[Ga1.04(1)Si0.96(1)O4]6 described in space group with lattice parameter a = 885.208(7) pm is reported. For such a sodalite with a deviation from a 1:1 ratio in the framework cations a body-centred structure in space group could be expected. The structure shows structural stress resulting from this unusual substitution by a high strain visible in reflections which are forbidden by symmetry in . Distinct amounts of Ga and Si are redistributed on the opposite crystallographic position. The second coordination sphere of Si was examined by 29Si MAS NMR, the absence of OH− in the sodalites cages was checked by FTIR- and Raman spectroscopy. The intensity distribution of MAS NMR signal is modelled using a new technique to calculate the framework metal second neighbour coordination. The confirmed distribution leads to a low thermal stability of the cubic sodalite indicated by a new intermediated phase which could be regarded as a triclinic distorted cancrinite with three-time increased c lattice parameter. This intermediate phase decomposes at around 1000 K to a beryllonite-type sodium gallosilicate.20621