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The influence of agitation of a frame impeller on thefluidizationperformance of Geldart D particles is experimentally and numericallystudied in a gas–solid stirred fluidized bed, using a three-dimensional(3D) unsteady computational fluid dynamics (CFD) simulation. The bedpressure drops obtained from simulations are in reasonable agreementwith those measured with pressure transducers, which validates theCFD models. The experimental results of the pressure fluctuation andthe simulated ones of the solid volume fraction distribution showthat Geldart D particles can perform homogeneous fluidization in thepresence of the impeller. The homogeneous fluidization regime expandsas the minimum bubbling velocity increases with the agitation speedwhile the minimum fluidizing velocity remains unaffected. In addition,the uniformity of particle velocities that are distributed in theentire fluidized bed is also improved by the agitation of the frameimpeller. [ABSTRACT FROM AUTHOR]

A versatile microporous metal-organic framework (MOF), {[Cu(TIA)]·1.5CH 3 OH} n ( Cu-1 ), was successfully obtained via the solvothermal reaction of cuprous(II) salt with the bifunctional ligand 3-(1 H -1,2,4-triazol-1-yl)isophthalic acid. Single-crystal X-ray diffraction studies indicate that Cu-1 contains an apo three-dimensional skeleton and two types of one-dimensional channels. The framework of Cu-1 has excellent acid-alkali resistance and thermal stability, which is stable in a pH = 2-13 aqueous solution and an 260 °C air environment. In addition, the microporous copper MOF shows very high uptakes of CO 2 (180 cm 3 ·g -1 ) and C 2 H 2 (113 cm 3 ·g -1 ) at 273 K and displays excellent adsorption selectivity for small molecular gases. The ideal adsorbed solution theory selectivity values for C 2 H 2 /C 2 H 4 , CO 2 /CH 4 , and CO 2 /N 2 are 2, 9, and 22 at 298 K, respectively. At the same time, breakthrough experiments for CO 2 /CH 4 , CO 2 /N 2 , and C 2 H 2 /C 2 H 4 were further conducted to verify the efficient separation performances.

Modulation of intermolecular interactions in response to external electric fields could be fundamental to the formation of unusual forms of water, such as water whiskers. However, a detailed understanding of the nature of intermolecular interactions in such systems is lacking. In this paper, we present novel theoretical results based on electron correlation calculations regarding the nature of H-bonds in water whiskers, which is revealed by studying their evolution under external electric fields with various field strengths. We find that the water whiskers consisting of 2-7 water molecules all have a chain-length dependent critical electric field. Under the critical electric field, the most compact chain structures are obtained, featuring very strong H-bonds, herein referred to as covalent H-bonds. In the case of a water dimer whisker, the bond length of the novel covalent H-bond shortens by 25%, the covalent bond order increases by 9 times, and accordingly the H-bond energy is strengthened by 5 times compared to the normal H-bond in a (H2O)2 cluster. Below the critical electric field, it is observed that, with increasing field strength, H-bonding orbitals display gradual evolutions in the orbital energy, orbital ordering, and orbital nature (i.e., from typical π-style orbital to unusual σ-style double H-bonding orbital). We also show that, beyond the critical electric field, a single water whisker may disintegrate to form a loosely bound zwitterionic chain due to a relay-style proton transfer, whereas two water whiskers may undergo intermolecular cross-linking to form a quasi-two-dimensional water network. Overall, these results help shed new insight on the effects of electric fields on water whisker formation.

Interesting effects of the cage unit size and number of cage units as well as bridge unit on the static first hyperpolarizabilities (β0) for novel multicage electrides are revealed. (1) The small cage unit C8 systems have larger β0 for cage unit size effect. (2) The β0 increases with increasing cage unit number. (3) The effect of the bridge between cage units on β0 is O > NH > CH2. Specially, a novel relationship between the excess electron cloud and β0 is revealed. Assembling the three effects, the constructed multicage electride structure with three small C8 cage units connected by the O-bridge (K···3C8(O)) is a electride salt K(+)[e@3C8(O)](-) and has the considerable β0 value of 7.1 × 10(5) au, which is about 55 times larger than the 13 000 au of the single-cage electride molecule Na3O(+)(e@C20F20)(-). The novel multicage strategy is effective to enhance nonlinear optical (NLO) response.

Using the strong electron hole cage C20F19 acceptor, the NH2...M/M3O (M = Li, Na, and K) complicated donors with excess electron, and the unusual σ chain (CH2)4 bridge, we construct a new kind of electride molecular salt e(-)@C20F19-(CH2)4-NH2...M(+)/M3O(+) (M = Li, Na, and K) with excess electron anion inside the hole cage (to be encapsulated excess electron-hole pair) serving as a new A-B-D strategy for enhancing nonlinear optical (NLO) response. An interesting push-pull mechanism of excess electron generation and its long-range transfer is exhibited. The excess electron is pushed out from the (super)alkali atom M/M3O by the lone pair of NH2 in the donor and further pulled inside the hole cage C20F19 acceptor through the efficient long σ chain (CH2)4 bridge. Owing to the long-range electron transfer, the new designed electride molecular salts with the excess electron-hole pair exhibit large NLO response. For the e(-)@C20F19-(CH2)4-NH2...Na(+), its large first hyperpolarizability (β0) reaches up to 9.5 × 10(6) au, which is about 2.4 × 10(4) times the 400 au for the relative e(-)@C20F20...Na(+) without the extended chain (CH2)4-NH2. It is shown that the new strategy is considerably efficient in enhancing the NLO response for the salts. In addition, the effects of different bridges and alkali atomic number on β0 are also exhibited. Further, three modulating factors are found for enhancing NLO response. They are the σ chain bridge, bridge-end group with lone pair, and (super)alkali atom. The new knowledge may be significant for designing new NLO materials and electronic devices with electrons inside the cages. They may also be the basis of establishing potential organic chemistry with electron-hole pair.