Search

Mechanical resonators, due to their capability to host ultralong-lived phonon modes, are particularly attractive for quantum state storage and as memory elements in conjunction with quantum computing and communication networks. Here we demonstrate absorptive-type coherent memory based on long-lived mechanical excitations. The itinerant coherent microwave field is captured, stored, and retrieved from a mechanical memory oscillator which is pre-cooled to the ground state. The phase space distribution allows us to distinguish between coherent and thermal components and study their evolution as a function of storage time. Our device exhibits attractive functions with an energy decay time of T1 = 15.9 s, a thermal decoherence rate of Γth = 2.85 Hz, and acquires less than one quantum noise during the τcoh = 55.7 ms storage period. We demonstrate that both the amplitude and phase information of microwave coherent states can be recovered, indicating the coherence of our memory device. These results suggest that high-Q mechanical resonators and long coherence time phonons could be ideal candidates for the construction of long-lived and on-demand microwave quantum memories. [ABSTRACT FROM AUTHOR]

Mesoporous AlPO4 materials have attracted much attention in catalysis due to their high thermal and chemical stability. Of particular interest for catalysis is the pure stoichiometry high surface area (> 500 m2/g) mesoporous AlPO4 (mAlPO4) glass prepared via a template-free aqueous sol–gel synthetic route. Toward the application of this material for catalysis, we have developed methods for loading it with nanoparticles (NPs) of catalytic metals—Pd and Rh—and carried out a detailed characterization study of the resulting doped materials by a wide array of analytical methods, including synchrotron X-ray absorption spectroscopy, inelastic neutron scattering and more. The applicability of this material for catalysis, both by itself and as a support for catalytic NPs, was then evaluated. The pure mAlPO4 exhibited excellent acid-catalyzed [3 + 2] cycloaddition of nitriles and sodium azide. mAlPO4 loaded with the Pd NPs catalyzed very efficiently deoxygenation reactions of benzyl alcohols. mAlPO4 loaded with Rh NPs catalyzed with high selectivity, the hydrogenation of phenols and cresols and full conversion the hydrogenation of the industrially very high-volume toluene to methylcyclohexane. The materials-science aspects of these successful catalysts were studied in detail, leading, for instance, to the understanding of the important role of the interfacial Rh/Pd–O-P bonds. [ABSTRACT FROM AUTHOR]

LaFeO3 modified with gold nanoparticles are synthesized by a simple wet chemical method. The structural and morphological characterizations of the Au-LaFeO3 nanocomposites are performed by various techniques such as X-ray diffraction, field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectrometer (XPS). In this experiment, the ethanol sensing performance of Au-LaFeO3 nanocomposites was studied by changing the amount of HAuCl4. The experimental results indicate that the sensors prepared with different volume of HAuCl4 solution show excellent gas sensing properties to ethanol. Au functionalization immensely improved the gas-sensing abilities of the LaFeO3 nanowires. At the optimum working temperature, the highest sensitivity of Au-LaFeO3 gas sensor to 100 ppm ethanol gas is 44, which is 27 times higher than that of LaFeO3 sensor. In addition, Au-LaFeO3 gas sensor has high selectivity and strong anti-interference ability to ethanol gas. The sensing mechanism of the Au-LaFeO3 gas sensor is also discussed in detail. [ABSTRACT FROM AUTHOR]

Full-Heusler alloy Fe2TiSn was predicted to be a potential thermoelectric material with high mechanical properties and stability. Fe2TiSn was usually prepared by arc-melting followed by annealing for 2 weeks, which takes a long time and consumes a large amount of energy. In this paper, Fe2TiSn was prepared by an ultra-fast method, self-propagating high-temperature synthesis (SHS) combined with spark plasma sintering. The bulk materials with uniform element distribution, well controlled composition and relative densities of over 97.5% were prepared. The undoped Fe2TiSn samples show p-type transport behavior. Co was heavily doped at the Fe site to prepare n-type Fe2−2xCo2xTiSn samples. The thermoelectric properties measurements carried out on the Co-doped samples show a highest ZT = 0.02 at 300 K, which is about tripe the performance of the pristine Fe2TiSn. This study provides a new approach for the rapid and low-cost preparation of full-Heusler thermoelectric materials. [ABSTRACT FROM AUTHOR]