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In this paper, we study a boundary value problem of fractional convection–diffusion equation with general two-sided fractional derivative. The well-posedness of the variation formulation is investigated under some properly assumptions. A Petrov-Galerkin method is developed, which employs the Jacobi poly-fractonomials for the trial and test space. The new approach allows the derivation of optimal error estimates in properly weighted Sobolev space and the matrix of the leading term is diagonal. We show that even for smooth data, we only obtain algebraic convergence due to the regularity of the solution. Some numerical examples are presented to demonstrate the validity of our theoretical results. [ABSTRACT FROM AUTHOR]

A novel crystalline high‐silica zeolite with 12×8‐membered ring (R) channel system is prepared with the aid of the 3D electron diffraction (3D ED) technique. A crystal with the same topology as one of the predicted daughter structures of CIT‐13 germanosilicate, named ECNU‐23 (East China Normal University 23) was coincidentally detected by the 3D ED investigation during the structure characterization of the "pure" powder sample of existing one‐dimension (1D) 10‐R ECNU‐21. By controlling the alkaline‐assisted hydrolysis under moderate conditions, we purified the phase of ECNU‐23 by selectively breaking and removing the chemically weak Ge(Si)‐O‐Ge and metastable Si‐O‐Si bonds. Its structure was determined based on the 3D ED data, and confirmed by high‐resolution TEM images and powder X‐ray diffraction (PXRD) data. The aluminosilicate Al‐ECNU‐23 shows unique catalytic properties in the isomerization/ disproportionation of m‐xylene as solid‐acid catalyst. [ABSTRACT FROM AUTHOR]

Abstract: An efficient strategy (enhanced metal oxide interaction and core–shell confinement to inhibit the sintering of noble metal) is presented confined ultrathin Pd‐CeOx nanowire (2.4 nm) catalysts for methane combustion, which enable CH4 total oxidation at a low temperature of 350 °C, much lower than that of a commercial Pd/Al2O3 catalyst (425 °C). Importantly, unexpected stability was observed even under harsh conditions (800 °C, water vapor, and SO2), owing to the confinement and shielding effect of the porous silica shell together with the promotion of CeO2. Pd‐CeOx solid solution nanowires (Pd‐Ce NW) as cores and porous silica as shells (Pd‐CeNW@SiO2) were rationally prepared by a facile and direct self‐assembly strategy for the first time. This strategy is expected to inspire more active and stable catalysts for use under severe conditions (vehicle emissions control, reforming, and water–gas shift reaction). [ABSTRACT FROM AUTHOR]

To study the shear behavior of post-cast concrete beams, six specimens with different shear-span ratios (0.3,0.5,0.8) and types of beam-column joints (cogging, straight seam with bent-up bars, cogging with bent-up bars) were designed and tested subjected to a monotonic load. Test results show that the share capacity of the joint is mainly composed of friction shear force, cogging shear force, reinforcement dowel force and bent bar shear force. Meanwhile, different shear-span ratios and beam-column joint types have significant effects on the shear capacity of the joints. The cogging shear force is the critical force with smaller shear-span ratios. The cogging force gradually decreases as the shear-span ratios grow. Meanwhile, bent-up bars could enhance the shear capacity of both cogging joints and straight seam joints. Based on the mechanism analysis and experimental research, the formula used to calculate the shear capacity of the connection was proposed in this paper. The calculation results from this formula agree with the testing results. So this formula can be regarded as a good theoretical reference for the shear capacity of post-cast concrete beams in engineering practice. [ABSTRACT FROM AUTHOR]

A novel crystalline high-silica zeolite with 12×8-membered ring (R) channel system is prepared with the aid of the 3D electron diffraction (3D ED) technique. A crystal with the same topology as one of the predicted daughter structures of CIT-13 germanosilicate, named ECNU-23 (East China Normal University 23) was coincidentally detected by the 3D ED investigation during the structure characterization of the "pure" powder sample of existing one-dimension (1D) 10-R ECNU-21. By controlling the alkaline-assisted hydrolysis under moderate conditions, we purified the phase of ECNU-23 by selectively breaking and removing the chemically weak Ge(Si)-O-Ge and metastable Si-O-Si bonds. Its structure was determined based on the 3D ED data, and confirmed by high-resolution TEM images and powder X-ray diffraction (PXRD) data. The aluminosilicate Al-ECNU-23 shows unique catalytic properties in the isomerization/ disproportionation of m-xylene as solid-acid catalyst., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The conversion of the alkali-treated intergrowth germanosilicate CIT-13 into the single-crystalline high-silica ECNU-21 (named after East China Normal University) zeolite, with a novel topology and a highly crystalline zeolite framework, has been realized through a creative top-down strategy involving a mild alkaline-induced multistep process consisting of structural degradation and reconstruction. Instead of acid treatment, hydrolysis in aqueous ammonia solution not only readily cleaved the chemically weak Ge(Si)-O-Ge bonds located within the interlayer double four ring (D4R) units of CIT-13, but also cleaved the metastable Si-O-Si bonds therein. This led to extensive removal of the D4R units, and also generated silanol groups on adjacent silica-rich layers, which then condensed to form a novel daughter structure upon calcination. Individual oxygen bridges in the reassembled ECNU-21 replaced the germanium-rich D4R units in CIT-13, thereby eliminating the original intergrowth phenomenon along the b axis. With an ordered crystalline structure of 10-ring (R) channels as well as suitable germanium-related Lewis acid sites, ECNU-21 serves as a stable solid Lewis acid catalyst for the shape-selective hydration of ethylene oxide (EO) to ethylene glycol (EG) at greatly reduced H 2 O/EO ratios and reaction temperature in comparison with the noncatalytic industrial process., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)