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Ge-containing Lewis acidic zeolites are typically synthesized using a conventional hydrothermal strategy from amorphous silica sources, through a long time- and energy-consuming approach limiting their wide applications. This study reports a rapid synthesis strategy for a series of IWV aluminogermanosilicate zeolites (T-x-Al) with a wide range of Si/Ge molar ratios (5–15) by interzeolite transformation of dealuminated FAU (DA-FAU). Notably, Ge-rich IWV could be obtained with crystallization time as short as one day by the equimolecular Si/Ge ratio gel. The effect of synthetic parameters was investigated and the obtained T-x-Al samples were characterized by XRD, SEM, EDS, ICP, 29Si and 27Al MAS NMR, FTIR, and N2 physisorption analyses. Compared with a previously reported IWV germanosilicate (H-3), T-x-Al displayed a better catalytic activity in Baeyer-Villiger (BV) oxidation, attributed to the presence of the active framework Ge sites with the assistance of the extra-framework Al species. The cyclic catalysis tests revealed that the presence of framework Al species contributed to the stability of the T-x-Al. Specifically, T-x-Al, with 14-membered ring (MR) supercages, outperformed the typical 12-MR Sn-beta catalyst in the BV oxidation of large ketone-like 2-admantanone, indicating a promising potential application in the macromolecular catalytic process. [ABSTRACT FROM AUTHOR]

This paper is concerned with event-triggered H∞ control of sampled-data systems. Its novelties lie in three aspects: (i) A novel accumulated-state-error-based event-triggered scheme is introduced by comparing the integral of the state error from tk to t with the system state sampled at tk. This condition works well due to the fact that the so-called Zeno behaviour does not occur. (ii) A novel Lyapunov functional is constructed to establish a criterion to ensure some certain H∞ performance of the closed-loop system. This Lyapunov functional is dependent on the integral of the state error involved in the event-triggered scheme. (iii) Under the event-triggered sampling scheme, suitable state-feedback controllers can be designed rather than be given a priori. Moreover, a self-triggered implementation of the proposed event-triggered sampling scheme is presented as well. Finally, a batch reactor model and an inverted pendulum system are given to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Elemental Te is important for semiconductor applications including thermoelectric energy conversion. Introducing dopants such as As, Sb, and Bi has been proven critical for improving its thermoelectric performance. However, the remarkably low solubility of these elements in Te raises questions about the mechanism with which these dopants can improve the thermoelectric properties. Indeed, these dopants overwhelmingly form precipitates rather than dissolve in the Te lattice. To distinguish the role of doping and precipitation on the properties, we have developed a correlative method to locally determine the structure-property relationship for an individual matrix or precipitate. We reveal that the conspicuous enhancement of electrical conductivity and power factor of bulk Te stems from the dopant-induced metavalently bonded telluride precipitates. These precipitates form electrically beneficial interfaces with the Te matrix. A quantum-mechanical-derived map uncovers more candidates for advancing Te thermoelectrics. This unconventional doping scenario adds another recipe to the design options for thermoelectrics and opens interesting pathways for microstructure design. Doping is a common strategy to improve thermoelectric performance yet limited to the solid solubility of dopants. Here, the authors find that forming metavalently bonded precipitates is key to property enhancement in Te rather than modifying the matrix lattice. [ABSTRACT FROM AUTHOR]

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