Searching low sintering temperature material with ultra-high Curie temperature (>800 °C) is urgent to seafloor hydrothermal vents detection. Bi 2 WO 6 , as the simplest member of the Aurivillius family was improved to possess ultra-high Curie temperature and ultra-high depolarization temperature by experiment at first time. The crystal structure was determined by ab initio and Rietveld refinement calculations. The symmetry group of ultra-high Curie temperature Bi 2 WO 6 is Aba 2 (41). The Curie temperatures of Bi 2(1−x) La 2x WO 6 (x=0, 0.005, 0.01, 0.02, 0.04) with increasing x are 952 °C, 1008 °C, 905 °C, 853 °C, 822 °C, respectively, and depolarization temperatures of them are around 915 °C, 905 °C, 880 °C, 800 °C, and 725 °C, respectively. The typical properties are as follows: Curie temperature T c =905 °C, depolarization temperature T d =880 °C, mechanical quality factor Q m =621.8, d 33 =17 pC/ N, K 33 =82.01, tanδ=0.19×10 −2 with x value of 0.01.

Herein a well-sealed and thermostated kinetics assembly is designed and built, which can run stirred at different reaction temperatures. With the reaction assembly above and the volumetric method together, the hydrogen peroxide (H 2 O 2) decomposition reaction kinetics is systematically investigated under a variety of reaction conditions over a copper-doped buserite-type layer manganese oxide (referred to as Cu-buserite) as a heterogeneous catalyst. The overall secondorder rate law is fitted out by the linear regression analysis, with the reaction orders with respect to both H 2 O 2 and Cu-buserite determined to each be equal to 1, and then explicitly explained by the proposed Michaelis-Menten like mechanism. The apparent activation energy E a is estimated as 33.5 ± 2.5 kJ mol −1 .

Micropower energy harvesting is one of key technologies for the micromation and practical development of wireless sensor and communication node networks. A self‐adaptive piezoelectric vibration system based on modified homogeneous strain asymmetric PZT piezoelectric ceramic cantilever beam for the micropower energy harvesting was designed and prepared. A vertical cantilever was designed at the first time to obtain the homogeneous state of stress which can largely increase the power output and energy harvesting efficiency of piezoelectric cantilevers. In order to achieve the self‐adaptive vibration, the asymmetric structure was adopted. Asymmetric cantilevers moved horizontally and changed the length of main cantilevers when affected by the variation in external frequency excitation, thus, the switching of resonant frequency was archived automatically without dissipating additional energy.

We study the characteristics of temperature fluctuation in two-dimensional turbulent Rayleigh-Bénard convection in a suqare cavity by means of direct numerical simulations. The Rayleigh number range is 1×108 ≤ Ra ≤ 1×1013, and the Prandtl number is selected as Pr=0.7 and Pr=4.3. It is found that, the temperature fluctuation profiles with respect to Ra exhibit two different distribution patterns. In the thermal boundary layer, the normalized fluctuation θ rms /θ rms,max is independent on Ra and a power law relation is identified, i.e., θ rms /θ rms,max ~(z/δ)0.99±0.01, where z/δ is a dimensionless distance to the boundary (δ is the thickness of thermal boundary layer). Out of the boundary layer, when Ra ≤ 5×109, the profiles of θ rms /θ rms,max descend, then ascend, and finally drop dramatically as z/δ increases. While for Ra ≥ 1×1010, the profiles continuously decrease and finally overlap with each other. The two different characteristics of temperature fluctuations are closely related to the formation of stable large-scale circulations and corner rolls. Besides, there is a critical value of Ra indicating the transition, beyond which the fluctuation <θ rms > V has a power law dependence on Ra, given by <θ rms > V ~Ra -0.14±0.01.