Extra-large pore zeolite (ITQ-40) with the lowest framework density containing double four- and double three-rings

AbstractRock deterioration under freeze–thaw cycles is a concern for in-service tunnel in cold regions. Previous studies focused on the change of rock mechanical properties under unidirectional stress, but the natural rock mass is under three dimensional stresses. This paper investigates influences of the number of freeze–thaw cycle on sandstone under low confining pressure. Twelve sandstone samples were tested subjected to triaxial compression. Additionally, the damage characteristics of sandstone internal microstructure were obtained by using acoustic emission (AE) and mercury intrusion porosimetry. Results indicated that the mechanical properties of sandstone were significantly reduced by freeze–thaw effect. Sandstone’ peak strength and elastic modulus were 7.28–37.96% and 6.38–40.87% less than for the control, respectively. The proportion of super-large pore and large pore in sandstone increased by 19.53–81.19%. We attributed the reduced sandstone’ mechanical properties to the degenerated sandstone microstructure, which, in turn, was associated with increased sandstone macropores. The macroscopic failure pattern of sandstone changed from splitting failure to shear failure with an increasing of freeze–thaw cycles. Moreover, the activity of AE signal increased at each stage, and the cumulative ringing count also showed upward trend with the increase of freeze–thaw number.

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Nano-Confinement of Insulating Sulfur in the Cathode Composite of All-Solid-State Li–S Batteries Using Flexible Carbon Materials with Large Pore Volumes

ACS Applied Materials & Interfaces ◽

10.1021/acsami.1c10275 ◽

2021 ◽

Author(s):

Masanori Yamamoto ◽

Shunsuke Goto ◽

Rui Tang ◽

Keita Nomura ◽

Yuichiro Hayasaka ◽

...

Keyword(s):

Solid State ◽

Carbon Materials ◽

Large Pore

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Solvent-Free Powder Synthesis and MOF-CVD Thin Films of the Large-Pore Metal–Organic Framework MAF-6

Chemistry of Materials ◽

10.1021/acs.chemmater.9b03807 ◽

2020 ◽

Vol 32 (5) ◽

pp. 1784-1793 ◽

Cited By ~ 8

Author(s):

Timothée Stassin ◽

Ivo Stassen ◽

João Marreiros ◽

Alexander John Cruz ◽

Rhea Verbeke ◽

...

Keyword(s):

Thin Films ◽

Metal Organic Framework ◽

Solvent Free ◽

Powder Synthesis ◽

Large Pore ◽

Metal Organic ◽

Organic Framework

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Anion packing density: a universal quantity for both dense and porous crystalline inorganic phases

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768102002689 ◽

2002 ◽

Vol 58 (3) ◽

pp. 457-462 ◽

Cited By ~ 1

Author(s):

F. Liebau ◽

H. Küppers

Keyword(s):

High Pressure ◽

Packing Density ◽

Three Dimensional ◽

Ionic Radii ◽

Generalized Framework ◽

Molal Volumes ◽

Definition Of ◽

Anion Packing ◽

Very High ◽

Framework Density

To compare densities of inorganic high-pressure phases their molal volumes or specific gravities are usually employed, whereas for zeolites and other microporous materials the so-called framework density, FD, is applied. The definition of FD, which refers only to phases with three-dimensional tetrahedron frameworks, is extended to a `generalized framework density' d f, which is independent of the dimensionality of the framework and the coordination number(s) of the framework cations. In this paper the anion packing density, d ap, is introduced as a new quantity which is not only applicable to any inorganic phase but, in contrast to FD and d f, also allows quantitative comparisons to be made for crystalline inorganic phases of any kind. The anion packing density can readily be calculated if the volume and content of the unit cell and the radii of the anions of a phase are known. From d ap values calculated for high-pressure silica polymorphs studied under very high pressure, it is concluded that Shannon–Prewitt effective ionic radii do not sufficiently take into account the compressibility of the anions.

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