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Direct Structural Identification of Gas Induced Gate‐Opening Coupled with Commensurate Adsorption in a Microporous Metal–Organic Framework 下载免费PDF全文
Dr. Debasis Banerjee Hao Wang Dr. Anna M. Plonka Dr. Thomas J. Emge Dr. John B. Parise Prof. Dr. Jing Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11816-11825
Gate‐opening is a unique and interesting phenomenon commonly observed in flexible porous frameworks, where the pore characteristics and/or crystal structures change in response to external stimuli such as adding or removing guest molecules. For gate‐opening that is induced by gas adsorption, the pore‐opening pressure often varies for different adsorbate molecules and, thus, can be applied to selectively separate a gas mixture. The detailed understanding of this phenomenon is of fundamental importance to the design of industrially applicable gas‐selective sorbents, which remains under investigated due to the lack of direct structural evidence for such systems. We report a mechanistic study of gas‐induced gate‐opening process of a microporous metal–organic framework, [Mn(ina)2] (ina=isonicotinate) associated with commensurate adsorption, by a combination of several analytical techniques including single crystal X‐ray diffraction, in situ powder X‐ray diffraction coupled with differential scanning calorimetry (XRD‐DSC), and gas adsorption–desorption methods. Our study reveals that the pronounced and reversible gate opening/closing phenomena observed in [Mn(ina)2] are coupled with a structural transition that involves rotation of the organic linker molecules as a result of interaction of the framework with adsorbed gas molecules including carbon dioxide and propane. The onset pressure to open the gate correlates with the extent of such interaction. 相似文献
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Gerlind Plonka Hagen Schumacher Manfred Tasche 《Advances in Computational Mathematics》2008,29(1):1-25
Biorthogonal wavelets are essential tools for numerous practical applications. It is very important that wavelet transforms
work numerically stable in floating point arithmetic. This paper presents new results on the worst-case analysis of roundoff
errors occurring in floating point computation of periodic biorthogonal wavelet transforms, i.e. multilevel wavelet decompositions
and reconstructions. Both of these wavelet algorithms can be realized by matrix–vector products with sparse structured matrices.
It is shown that under certain conditions the wavelet algorithms can be remarkably stable. Numerous tests demonstrate the
performance of the results.
相似文献
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The problem of recovering translates and corresponding amplitudes of sparse sums of Gaussians out of sampling values as well as reconstructing sparse sums of exponentials are nonlinear inverse problems that can be solved for example by Prony's method. Here, we want to demonstrate a new extension to multivariate input data. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Anna M. Plonka Debasis Banerjee John B. Parise 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(11):m335-m337
The title compound, [Mg2(C12H14O4)2]n, is the first example of an s‐block metal adamantanedicarboxylate coordination polymer. The asymmetric unit comprises two crystallographically unique MgII centers and two adamantane‐1,3‐dicarboxylate ligands. The compound is constructed from a combination of chains of corner‐sharing magnesium‐centered polyhedra, parallel to the a axis, connected by organic linkers to form a layered polymer. The two MgII centers are present in distorted tetrahedral and octahedral coordination environments derived from carboxylate O atoms. Tetrahedrally coordinated MgII centers have been reported in organometallic compounds, but this is the first time that such coordination has been observed in a magnesium‐based coordination polymer. The bond valance sums of the two MgII centers are 2.05 and 2.11 valence units, matching well with the expected value of 2. 相似文献
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C. Düsing P. Geltenbort C. Plonka Yu. N. Pokotilovski 《Physics of Particles and Nuclei Letters》2018,15(5):541-550
The experimental setup for examining the low-molecular-weight CF3(CF2)3–O–CF2–O–(CF2)3CF3 fluoropolymer, which is a promising coating material for the walls of storage chambers for ultracold neutrons, is described. The results are detailed. The measurement data are interpreted in the model of a multilayer complex quantum-mechanical potential of the chamber walls. 相似文献
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The post-irradiation decay of electrons trapped in low-temperature glasses has been analyzed either in terms of tunnelling models which invoke direct transfer of electrons from initial solvent traps to acceptors or in terms of a first order reaction with a time-dependent rate constant of the form
, O<1. This particular form of time-dependent rate constant was believed to be unique for the CTRW model of MONTROLL and WEISS. It is shown that the time-dependent rate constant calculated from the tunnelling models can be adequately approximated by this particular form with O<0.1. 相似文献
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We derive a new method for optimal ℓ2-approximation of discrete signals on ℓ2(ℕ0) whose entries can be represented as an exponential sum of finite length. Our approach employs Prony's method in a first step to recover the exponential sum that is determined by the signal. In the second step we use the theory of Adamjan, Arov and Krein (AAK) to derive an algorithm for computing a shorter exponential sum that approximates the original signal in the ℓ2-norm well. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Daniela Ro?ca Gerlind Plonka 《Journal of Computational and Applied Mathematics》2011,236(6):1033-1041
We construct an area preserving map from a cube to the unit sphere S2, both centered at the origin. More precisely, each face Fi of the cube is first projected to a curved square Si of the same area, and then each Si is projected onto the sphere by inverse Lambert azimuthal equal area projection, with respect to the points situated at the intersection of the coordinate axes with S2. This map is then used to construct uniform and refinable grids on a sphere, starting from any grid on a square. 相似文献