Dalian University of Technology

About: Dalian University of Technology is a education organization based out in Dalian, China. It is known for research contribution in the topics: Catalysis & Finite element method. The organization has 60890 authors who have published 71921 publications receiving 1188356 citations. The organization is also known as: Dàlián Lǐgōng Dàxué.

New Membrane Architecture with High Performance: ZIF-8 Membrane Supported on Vertically Aligned ZnO Nanorods for Gas Permeation and Separation

Abstract: A new ZIF-8 membrane architecture with high performance supported on vertically aligned ZnO nanorods was successfully prepared. The vertically aligned, single crystal ZnO nanorods were grown seamlessly from porous ceramic support to form an intermediate support layer for the ZIF-8 membrane. They provide multiple anchorages for the ZIF-8 membrane that are both strong and flexible. The nanorods were activated to induce a uniform nucleation of ZIF nuclei on their surface to initiate and guide the growth of a defect-free ZIF-8 membrane. Single gas permeations and binary separations carried out to investigate the transport properties of these new membrane architectures confirmed that the ZIF-8 membranes were free of defects and stable at a higher temperature (473 K).

Synchrotron X-ray computed microtomography study on gas hydrate decomposition in a sedimentary matrix

Abstract: In-situ synchrotron X-ray computed microtomography with sub-micrometer voxel size was used to study the decomposition of gas hydrates in a sedimentary matrix. Xenon-hydrate was used instead of methane hydrate to enhance the absorption contrast. The microstructural features of the decomposition process were elucidated indicating that the decomposition starts at the hydrate-gas interface; it does not proceed at the contacts with quartz grains. Melt water accumulates at retreating hydrate surface. The decomposition is not homogeneous and the decomposition rates depend on the distance of the hydrate surface to the gas phase indicating a diffusion-limitation of the gas transport through the water phase. Gas is found to be metastably enriched in the water phase with a concentration decreasing away from the hydrate-water interface. The initial decomposition process facilitates redistribution of fluid phases in the pore space and local re-formation of gas hydrates. The observations allow also rationalizing earlier conjectures from experiments with low spatial resolutions and suggest that the hydrate-sediment assemblies remain intact until the hydrate spacers between sediment grains finally collapse; possible effects on mechanical stability and permeability are discussed. The resulting time resolved characteristics of gas hydrate decomposition and the influence of melt water on the reaction rate are of importance for a suggested gas recovery from marine sediments by depressurization. This article is protected by copyright. All rights reserved.

Crossings and Nestings of Matchings and Partitions

Abstract: We present results on the enumeration of crossings and nestings for matchings and set partitions. Using a bijection between partitions and vacillating tableaux, we show that if we fix the sets of minimal block elements and maximal block elements, the crossing number and the nesting number of partitions have a symmetric joint distribution. It follows that the crossing numbers and the nesting numbers are distributed symmetrically over all partitions of $[n]$, as well as over all matchings on $[2n]$. As a corollary, the number of $k$-noncrossing partitions is equal to the number of $k$-nonnesting partitions. The same is also true for matchings. An application is given to the enumeration of matchings with no $k$-crossing (or with no $k$-nesting).

MXene Ti3C2Tx for phase change composite with superior photothermal storage capability

Abstract: The latent heat storage of PCMs has gained increasing attention in the solar energy application field due to their high thermal energy storage density. However, the lack of energy conversion ability of the organic PCMs results in the low utilization efficiency of solar energy. Herein, we report a novel PEG/Ti3C2Tx layered composite PCM with superior photothermal storage capability, which consists of stacked Ti3C2Tx nanosheets and PEG filled within the spaces between the flakes. The resulting composites exhibited a strong absorption capacity for electromagnetic waves at the UV-Vis-NIR region. Notably, there are two enhanced absorption bands at the visible and near-infrared regions due to the localized surface plasmon resonance (LSPR) effect of the Ti3C2Tx nanosheets, which endows the composite PCM with excellent photo-to-thermal storage efficiencies (up to 94.5%) under actual solar light irradiation. In addition, the composite PCM also possesses a high energy storage density and form-stable property before and after the phase transition. These results indicate that the synthesized composite presents superior comprehensive properties suitable for solar energy storage applications.