A Study on Photoacoustic Phase Spectra of Rare Earth Complexes with Oxine

Photoacoustic phase is the time delay that occurs from light to acoustic signal. the phase includes two components: one is the time delay that occurs during the process in which light absorbed by a sample converts into heat; the other is the time delay caused from heat to acoustic signal. a modified formula of PA phase is presented based on the R-G theory considering the phase caused by non-radiative relaxation processes. the phase is associated with absorption coefficient (β), thermal diffusion length of sample (μ_s), the longest lifetime of all excited states (r), and the ratio of rapid to slow heat component (R). When the photoacoustic signal is saturated the phase is associated with only T and R. the effect of different rare earth ions on the PA phase spectra of the ligand (oxine) in the rare earth complexes are reported and are well explained by using the phase formula of PA saturation.     

Highly transparent cerium doped gadolinium gallium aluminum garnet ceramic prepared with precursors fabricated by ultrasonic enhanced chemical co-precipitation

Cerium doped gadolinium gallium aluminum garnet (GGAG:Ce) ceramic precursors have been synthesized with an ultrasonic chemical co-precipitation method (UCC) and for comparison with a traditional chemical co-precipitation method (TCC). The effect of ultra-sonication on the morphology of powders and the transmittance of GGAG:Ce ceramics are studied. The results indicate that the UCC method can effectively improve the homogenization and sinterability of GGAG:Ce powders, which contribute to obtain high transparent GGAG ceramic with the highest transmittance of 81%.     

Nickel-Catalyzed Cross-Coupling of Ethyl Chlorofluoroacetate with Aryl Bromides

A combinatorial nickel-catalyzed monofluoroalkylation of aryl bromides with the industrial raw regent ethyl chlorofluoroacetate has been developed. The two key factors to successful conversion are the combination of nickel with readily available nitrogen and phosphine ligands and the using of a mixture of different solvents. Mechanistic investigations indicated a new zinc regent might generated in situ and be involved in the reaction process.     

Extended phase diagram of La1-xCaxMnO3 by interfacial engineering

The interfacial enhanced ferromagnetism in maganite/ruthenate system is regarded as a promising path to broaden the potential of oxide-based electronic device applications. Here, we systematically studied the physical properties of LaLa_1-xCa_xMnO₃/SrRuO₃ superlattices and compared them with the LaLa_1-xCa_xMnO₃ thin films and bulk compounds. The LaLa_1-xCa_xMnO₃/SrRuO₃ superlattices exhibit significant enhancement of Curie temperature (T_C) beyond the corresponding thin films and bulks. Based on these results, we constructed an extended phase diagram of LaLa_1-xCa_xMnO₃ under interfacial engineering. We considered the interfacial charge transfer and structural proximity effects as the origin of the interface-induced high T_C. The structural characterizations revealed a pronounced increase of B-O-B bond angle, which could be the main driving force for the high T_C in the superlattices. Our work inspires a deeper understanding of the collective effects of interfacial charge transfer and structural proximity on the physical properties of oxide heterostructures.     

Brin–Katok formula for the measure theoretic r-entropy

Entropy is undoubtedly among the most essential characteristics of dynamical systems. Calculations of various entropies are important but often difficult. This article is devoted to constructing the Brin–Katok formula for the measure theoretic r-entropy.     

Association,emulsifying, and solubilization properties of amphiphilic hyperbranched poly(acrylic acid) with short polystyrene stickers

Amphiphilic hyperbranched copolymer chains made of large hyperbranched poly(acrylic acid) cores grafted with short polystyrene stickers (HB‐PAA_n‐g‐PS_{n + 1}) with different n values (n = 1, 10, 47) were well prepared and confirmed by size exclusion chromatography, Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance. The study on the interchain association behavior of these amphiphilic chains indicates that larger HB‐(PAA)_n‐g‐(PS)_{n + 1} copolymer chains have a less tendency to undergo interchain association. Moreover, the simple vial‐inversion and rheological experiments show that the apparent critical gel concentration (C_g) decreases with n, but no sol–gel transition was observed for triblock PS‐PAA‐PS even when the concentration is up to 200 g L^?1. Further transmission electron microscopy study of the latex particles prepared with HB‐(PAA)_n‐g‐(PS)_{n + 1} as surfactant reveals that the latex particles are spherical and narrowly dispersed; while the measured latex particle number (N_p) indicates the surfactant efficiency of HB‐(PAA)₄₇‐g‐(PS)₄₈ is poorer than that of triblock PS‐PAA‐PS (n = 1). Finally, pyrene solubilization measurement shows the solubilization efficiency of HB‐(PAA)_n‐g‐(PS)_{n + 1} copolymers decreases with n, consistent with the previous observed interchain association result. The present study demonstrates that both the chain topology and the styrene weight fraction dominates the final solution properties of amphiphilic HB‐(PAA)_n‐g‐(PS)_{n + 1} chains in aqueous solution. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 128–138     

Synthesis of worm-like superparamagnetic P(St-AA)@Fe3O4/SiO2 Janus composite particles

Novel Janus nanocomposite particles with superparamagnetic P(St-AA)@Fe₃O₄ seed microspheres as head and worm-like SiO₂ as body were successfully prepared. The effects of different variables such as the amount of cetyltrimethyl ammonium bromide (CTAB), tetraethyl orthosilicate (TEOS), and ammonia and the composition of inorganic precursors and surfactants on the morphologies of final particles were studied by transmission electron microscopy (TEM) and field-emission scanning electron microscopy (SEM). Due to the amphiphilic difference between the two parts as well as their special morphologies, the fabricated worm-like particles could be applied to stabilize oil/water mixtures even if owing relative hydrophilic properties that might provide a new category of functional solid surfactants in Pickering emulsions and the fabrication of hierarchical materials.