On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

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The Observation of Gravitational Waves from a Binary Black Hole Merger

Jenny Schneider,*,† Masaya Matsuoka,‡ Masato Takeuchi,‡ Jinlong Zhang, Yu Horiuchi,‡ Masakazu Anpo,‡ and Detlef W. Bahnemann*,† †Institut fur Technische Chemie, Leibniz Universitaẗ Hannover, Callinstrasse 3, D-30167 Hannover, Germany ‡Faculty of Engineering, Osaka Prefecture University, 1 Gakuen-cho, Sakai Osaka 599-8531, Japan Key Lab for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China

Understanding TiO2 photocatalysis: mechanisms and materials.

Through a combined use of experimental and theoretical approaches such as XRPD, EXAFS, IR, and UV−vis spectroscopies and ab initio periodic DFT calculations, we report a detailed characterization of structural, vibrational, and electronic properties of UiO-66 (Zr-BDC MOF) in its hydroxylated and dehydroxylated forms. The stability of the materials with respect to the most common solvents, acids, and bases is determined by combining XRPD and TGA/MS techniques. The structures of the two forms of UiO-66 are refined through an interactive XRPD/EXAFS approach and validated by ab initio calculations. Experimental and calculated IR spectra are reported and compared to enlighten the nature of vibrational modes upon dehydroxylation and to show the complete reversibility of the dehydration/hydration phenomenon. Experimental and calculated band gaps are also reported and compared. In this work, we show the necessity to combine, in a synergic way, different experimental techniques and periodic ab initio approaches to...

Disclosing the Complex Structure of UiO-66 Metal Organic Framework: A Synergic Combination of Experiment and Theory

Acid catalysts in industrial hydrocarbon chemistry.

https://pureadmin.qub.ac.uk/ws/files/15831115/polymeric.pdf

Polymeric materials based on silk proteins

Ten zirconia powders have been characterized by XRD, FT-IR/FT-FIR and Raman skeletal spectroscopies and DR-UV electronic spectroscopy. The vibrational features of a yttria-stabilized cubic zirconia and of tetragonal, monoclinic and tetragonal + monoclinic pure zirconia mixtures have been discussed. Assignments for the vibrational features of cubic and tetragonal samples are proposed. The origin of very broad vibrational peaks in tetragonal zirconia is briefly addressed. The vibrational spectra provide evidence for the presence of trigonal oxide ions in the monoclinic phase only. The UV spectra show that monoclinic zirconia (where the coordination of zirconium is sevenfold) absorbs at lower energy than the cubic and tetragonal phases (where the coordination of zirconium is eightfold). However, it absorbs at higher energy than the perovskite SrZrO3 where Zr adopts octahedral coordination. The origin of the shifts of the corresponding
absorption edges is discussed.

Vibrational and electronic spectroscopic properties of zirconia powders

Raman characterisation of powder of cubic RE2O3 (RE = Nd, Gd, Dy, Tm, and Lu), Sc2O3 and Y2O3

A structural study of Sm- and Gd-doped ceria was performed with the aim to clarify some unexplained structural features. (Ce1-xREx)O2-x/2 samples (RE ≡ Sm, Gd; x = 0, 0.1, ..., 1) were prepared by coprecipitation of mixed oxalates and subsequent thermal treatment at 1473, 1173, or 1073 K in air; they were then analyzed at room temperature both by synchrotron X-ray diffraction and μ-Raman spectroscopy. Two structural models were adopted to fit the experimental data, namely, a fluoritic one, resembling the CeO2 structure at low RE content, and a hybrid one at higher RE content, intermediate between the CeO2 and the RE2O3 structures. Two main transitions were detected along the compositional range: (a) an RE-dependent transition at the boundary between the fluoritic and the hybrid regions, of a chemical nature; (b) an RE-independent transition within the hybrid region at ∼0.5, having a purely geometrical nature. The presence of two finely interlaced F- and C-based structures within the hybrid region was confirmed, and hints of their composition were obtained by μ-Raman spectroscopy. The obtained results indicate a possible explanation for the non-Vegard behavioral trend of the cell parameters.

Structural features of Sm- and Gd-doped ceria studied by synchrotron X-ray diffraction and μ-Raman spectroscopy.

The N-doped TiO2 has been synthesized by sol–gel method, using titanium isopropoxide, isopropanol and an aqueous solution of ammonia with ratio 2:1:10. The concentrations used for the NH3 aqueous solution were 3, 7, 10 and 15 %. The samples have been analysed by X-ray diffraction, electron microscopy (SEM and TEM) thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), micro-Raman spectroscopy and diffuse reflectivity. TEM, SEM, DSC and TGA showed that the morphology is influenced by the presence of N3− ions but not by the concentration of the solution. Instead reflectance gave us a relation between values of the energy gap and the concentration of N3− ions: the gap between valence and conduction band lowers as the concentration of NH3 in the starting solution increases. From these results we can say that the properties of the material have been tuned by doping with nitrogen ions because the particles absorb more light in the visible range, and this is important for photovoltaic and photocatalytic applications.

https://link.springer.com/content/pdf/10.1007%2Fs10971-012-2756-0.pdf

Synthesis and characterization of nitrogen-doped TiO2 nanoparticles prepared by sol–gel method

A room temperature structural study has been performed through the whole compositional range of the (Ce1–xLux)O2–x/2 system by synchrotron X-ray diffraction and μ-Raman spectroscopy. Samples were synthesized by thermal treatment in air at 1373 K of coprecipitated mixed oxalates. A CeO2-based solid solution with a fluorite-type structure (F) was found to be stable up to x = 0.4, while at higher Lu content a (F + C) biphasic region was observed, with C being the cubic atomic arrangement typical of sesquioxides of the heaviest rare earths. A comparative approach including also results deriving from other (Ce1–xREx)O2–x/2 systems (RE ≡ Gd and Sm) allowed us to conclude that the compositional extent of the F solid solution is a complex function of RE3+ size and RE compressibility. On this basis, the dependence of ionic conductivity on the RE identity was interpreted as related both to the Ce4+/RE3+ size closeness and to RE compressibility. Ce4+/RE3+ dimensional issues were also revealed to rule the appearance ...

Maria Maddalena Carnasciali

Papers

Vibrational and electronic spectroscopic properties of zirconia powders

Raman characterisation of powder of cubic RE2O3 (RE = Nd, Gd, Dy, Tm, and Lu), Sc2O3 and Y2O3

Structural features of Sm- and Gd-doped ceria studied by synchrotron X-ray diffraction and μ-Raman spectroscopy.

Synthesis and characterization of nitrogen-doped TiO2 nanoparticles prepared by sol–gel method

Lu-, Sm-, and Gd-Doped Ceria: A Comparative Approach to Their Structural Properties