Vibrational and structural properties of lead-free piezoelectric (1-x)Na0.5Bi0.5TiO3–xCaTiO3 (0 < x < 1.00) solid solutions have been investigated using Raman spectroscopy and X-ray diffraction. Different anomalies were detected and analyzed taking into consideration the phase transition from rhombohedral to orthorhombic phase at room temperature. All Raman bands were interpreted through the variation in the peak positions (frequency) and the corresponding half-widths at half maximum (HWHM) as a function of x. XRD used as a complementary technique to Raman spectroscopy, showed that the rhombohedral – orthorhombic phase transition went gradually through an intermediate phase consisting of a mixture of rhombohedral (R3c) and orthorhombic (Pnma) structures and that the fraction of orthorhombic phase increased with CT composition. The results show that the morphotropic phase boundary (MPB) is located between 0.09 and 0.15.
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Light scattering is a fundamental property that can be exploited to create essential devices such as particle analysers. The most common particle size analyser relies on measuring the angle-dependent diffracted light from a sample illuminated by a laser beam. Compared to other non-light-based counterparts, such a laser diffraction scheme offers precision, but it does so at the expense of size, complexity and cost. In this paper, we introduce the concept of a new particle size analyser in a collimated beam configuration using a consumer electronic camera and machine learning. The key novelty is a small form factor angular spatial filter that allows for the collection of light scattered by the particles up to predefined discrete angles. The filter is combined with a light-emitting diode and a complementary metal-oxide-semiconductor image sensor array to acquire angularly resolved scattering images. From these images, a machine learning model predicts the volume median diameter of the particles. To validate the proposed device, glass beads with diameters ranging from 13 to 125 µm were measured in suspension at several concentrations. We were able to correct for multiple scattering effects and predict the particle size with mean absolute percentage errors of 5.09% and 2.5% for the cases without and with concentration as an input parameter, respectively. When only spherical particles were analysed, the former error was significantly reduced (0.72%). Given that it is compact (on the order of ten cm) and built with low-cost consumer electronics, the newly designed particle size analyser has significant potential for use outside a standard laboratory, for example, in online and in-line industrial process monitoring.
MULTIFILE
The reaction of the alkyl complexes Cp*2LnCH(SiMe 3)2 (Ln = Y 1-Y, Ce 1-Ce, La 1-La; Cp* = η5-C5Me5) and Me2Si(η 5-C5Me4)2LnCH(SiMe3) 2 (Ln = Ce 5-Ce) with 1-methylalk-2-ynes CH3C≡CR (R = Me 3a, Et 3b, nPr 3c, tBu 3d, SiMe3 3e, Ph 3f, C6H4Me-2 3g, C6H3Me 2-2,6 3h, C6H3iPr2-2,6 3i, C6F5 3j) affords the corresponding η3-propargyl/allenyl complexes Cp*2LnCH 2CCR (4a-j-Ln) and Me2Si(η5-C 5Me4)2CeCH2CCR (6a-j-Ce) via propargylic metalation. The hydride complexes [Cp*2Ln(μ-H)] 2 (Ln = Y 2-Y, Ce 2-Ce, La 2-La) react rapidly with 3 to produce mixtures of insertion and propargylic metalation products, and the relative rate of these processes depends on the metal and alkyne substituent. Selected η3-propargy/allenyl complexes Cp*2YCH 2CCR (R = Me 4a-Y, Ph 4f-Y), Cp*2CeCH2CCR (R = Me 4a-Ce, Ph 4f-Ce), Cp*2CeCH(Me)CCEt (9b-Ce), Cp*2LaCH2CCR (R = Ph 4f-La, C6H 3Me2-2,6 4h-La) are obtained on a preparative scale and characterized by NMR spectroscopy, IR spectroscopy, and cryoscopy. Compounds 4f-Y and 4f-La are also characterized by single-crystal X-ray diffraction. The reactions of the η3-propargyl/allenyl complexes with Brønsted acids, such as alcohols and acetylenes, afford the corresponding substituted allenes (RCH=C=CH2) and 1-methylalk-2-ynes (CH 3C≡CR) as organic products. The reactions of 4f-Y and 4f-La with Lewis bases, such as pyridine and THF, yield die corresponding base adducts. The adduct 4f-La · py is characterized by single-crystal X-ray diffraction, revealing an η3-coordinated propargyl/allenyl ligand. © 2008 American Chemical Society.
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