We performed precise measurement of the refractive index of stable silicon isotopes 28Si, 29Si, and 30Si single crystals with enrichments above 99.9 at.% and a silicon single-crystal natSi of natural isotopic composition with the Fourier-transform interference refractometry method from 1.06 to more than 80 μm with 0.1 cm(-1) resolution and accuracy of 2×10(-5)…1×10(-4). The oxygen and carbon concentrations in all crystals are within 5×10(15) cm(-3), and the content of the metal impurities is 10(-5)…10(-6) at.%. The peculiar changes of the refractive index in the phonon absorption region of all silicon single crystals are shown. The coefficients of the generalized Cauchy dispersion function approximating the experimental refractive index values all over the measuring range are given. The transmission and Raman spectra are also studied.
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http://dx.doi.org/10.1364/AO.50.004633 | DOI Listing |
Nature
January 2025
Department of Materials Engineering, Indian Institute of Science, Bangalore, India.
Piezoelectric materials directly convert between electrical and mechanical energies. They are used as transducers in applications such as nano-positioning and ultrasound imaging. Improving the properties of these devices requires piezoelectric materials capable of delivering a large longitudinal strain on the application of an electric field.
View Article and Find Full Text PDFSci Rep
January 2025
ISQI, Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań, Poland.
High-resolution Brillouin spectroscopy was employed to investigate the anisotropy in surface wave velocities within a bulk single crystal of SbTe, a well-known layered van der Waals material. By leveraging the bulk elastic constants derived from various simulation methods, we were able to theoretically calculate the distribution of surface acoustic phonon velocities on the cleavage plane of the material. Upon analyzing multiple simulation results, it became evident that the most significant discrepancies arose in the calculations of the elastic constant c, with values ranging from 48 to 98 GPa.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
CSSB Centre for Structural Systems Biology, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
Dinucleases of the DEDD superfamily, such as oligoribonuclease, Rexo2 and nanoRNase C, catalyze the essential final step of RNA degradation, the conversion of di- to mononucleotides. The active sites of these enzymes are optimized for substrates that are two nucleotides long, and do not discriminate between RNA and DNA. Here, we identified a novel DEDD subfamily, members of which function as dedicated deoxydinucleases (diDNases) that specifically hydrolyze single-stranded DNA dinucleotides in a sequence-independent manner.
View Article and Find Full Text PDFBiosystems
January 2025
Lomonosov Moscow State University, Moscow, Russian Federation. Electronic address:
As an important part of lipid metabolism the liver produces large particles called very low density lipoproteins, filled mostly with triglyceride and cholesterol esters mixture. A large percentage of the mixture composition components has a melting point above physiological temperature. Thus solid cluster formation or phase transition could be expected.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Science, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560, Japan.
Two 3D/2D anionic metal-organic frameworks (MOFs), [Cu(HL)] () and [Mn(L)(DMF)] ( (DMF = ,-dimethylformamide), were synthesized by the solvothermal reaction of metal salts and 5'-(4-carboxyphenyl)-2',4',6'-triethyl-[1,1':3',1″-terphenyl]-4,4″-dicarboxylic acid (HL). Single-crystal X-ray diffraction analyses revealed that complex shows three-dimensional (3D) frameworks with a (3,6)-connected 3-fold interpenetrated topology with the Schläfli symbols of {4.6}{4.
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