Corrigendum to “Effects of initial crystal structure of Fe2O3 and Mn promoter on effective active phase for syngas to light olefin” [Appl. Catal. B: Environ. 261 (2020) 118219]

2020 ◽  
Vol 278 ◽  
pp. 119287
Author(s):  
Yi Liu ◽  
Fangxu Lu ◽  
Yu Tang ◽  
Minyang Liu ◽  
Franklin Feng Tao ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Active Phase ◽  
Light Olefin ◽  
Initial Crystal

Effects of initial crystal structure of Fe2O3 and Mn promoter on effective active phase for syngas to light olefins

2020 ◽  
Vol 261 ◽  
pp. 118219 ◽  
Author(s):  
Yi Liu ◽  
Fangxu Lu ◽  
Yu Tang ◽  
Minyang Liu ◽  
Franklin Feng Tao ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Active Phase ◽  
Light Olefins ◽  
Initial Crystal

scholarly journals Investigation of Solvatomorphism and Its Photophysical Implications for Archetypal Trinuclear Au3(1-Methylimidazolate)3

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4404
Author(s):  
Shengyang Guan ◽  
David C. Mayer ◽  
Christian Jandl ◽  
Sebastian J. Weishäupl ◽  
Angela Casini ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Density Functional ◽  
Bulk Material ◽  
Variable Temperature ◽  
Active Phase ◽  
Solvent Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aurophilic Interactions

A new solvatomorph of [Au3(1-Methylimidazolate)3] (Au3(MeIm)3)—the simplest congener of imidazolate-based Au(I) cyclic trinuclear complexes (CTCs)—has been identified and structurally characterized. Single-crystal X-ray diffraction revealed a dichloromethane solvate exhibiting remarkably short intermolecular Au⋯Au distances (3.2190(7) Å). This goes along with a dimer formation in the solid state, which is not observed in a previously reported solvent-free crystal structure. Hirshfeld analysis, in combination with density functional theory (DFT) calculations, indicates that the dimerization is generally driven by attractive aurophilic interactions, which are commonly associated with the luminescence properties of CTCs. Since Au3(MeIm)3 has previously been reported to be emissive in the solid-state, we conducted a thorough photophysical study combined with phase analysis by means of powder X-ray diffraction (PXRD), to correctly attribute the photophysically active phase of the bulk material. Interestingly, all investigated powder samples accessed via different preparation methods can be assigned to the pristine solvent-free crystal structure, showing no aurophilic interactions. Finally, the observed strong thermochromism of the solid-state material was investigated by means of variable-temperature PXRD, ruling out a significant phase transition being responsible for the drastic change of the emission properties (hypsochromic shift from 710 nm to 510 nm) when lowering the temperature down to 77 K.

The symmetry origin of the austenite-cementite orientation relationships in steels

2019 ◽  
Vol 234 (4) ◽  
pp. 237-245 ◽  
Author(s):  
Valentin Kraposhin ◽  
Alexander Talis ◽  
Nenad Simich-Lafitskiy
Keyword(s):  
Crystal Structure ◽  
Orientation Relationship ◽  
Formation Mechanism ◽  
Mutual Orientation ◽  
Crystallographic Group ◽  
Mutual Transformation ◽  
Orientation Relationships ◽  
Nucleus Formation ◽  
Crystallographic Symmetry ◽  
Initial Crystal

Abstract The connection between austenite/cementite orientation relationships and crystal structure of both phases has been established. The nucleus formation mechanism at the mutual transformation of austenite and cementite structures has been proposed. Mechanism is based on the interpretation of the considered structures as crystallographic tiling onto triangulated polyhedra, and the said tiling can be transformed by diagonal flipping in a rhombus consisting of two adjacent triangular faces. The sequence of diagonal flipping in the fragment of the initial crystal determines the orientation of the fragment of the final crystal relative to the initial crystal. In case of the mutual austenite/cementite transformation the mutual orientation of the initial and final fragments is coinciding to the experimentally observed in steels Thomson-Howell orientation relationships: ${\left\{ {\bar 103} \right\}_{\rm{C}}}||{\left\{ {111} \right\}_{\rm{A}}};{\rm{}} < {\kern 1pt} 010{\kern 1pt} { > _{\rm{C}}}{\rm{||}} < {\kern 1pt} 10\bar 1{\kern 1pt} { > _{\rm{A}}};\; < {\kern 1pt} 30\bar 1{\kern 1pt} { > _{\rm{C}}}\;||\,\, < {\kern 1pt} \bar 12\bar 1{\kern 1pt} { > _{\rm{A}}}{\rm{}}$ The observed orientation relationship between FCC austenite and cementite is determined by crystallographic group-subgroup relationship between transformation participants, and non-crystallographic symmetry which is determining the transformation of triangulated clusters of transformation participants.

Influence of initial crystal structure and electrical pulsing on densification of nanocrystalline alumina powder

1998 ◽  
Vol 13 (1) ◽  
pp. 86-89 ◽  
Author(s):  
R. S. Mishra ◽  
S. H. Risbud ◽  
A. K. Mukherjee
Keyword(s):  
Crystal Structure ◽  
High Density ◽  
Theoretical Density ◽  
Alumina Powder ◽  
Temperature Range ◽  
Initial Crystal ◽  
Nanocrystalline Alumina

The effect of the crystal structure of starting alumina powder and electric pulsing on the initial stages of densification has been studied in the temperature range of 1200– 1500 °C. Multiple electric pulsing cycles enhance the densification significantly. The α-alumina powders consolidate more readily in comparison to γ-alumina powders. A high density α-alumina specimen (>98% of theoretical density) was obtained at 1300 °C in less than 10 min.

SELECTION OF BEST CRYSTAL STRUCTURE FOR INITIATING DOCKING-BASED VIRTUAL SCREENING STUDIES OF CDK2 INHIBITORS: A CROSS-DOCKING AND DUD SET VALIDATION APPROACH

INDIAN DRUGS ◽  
2019 ◽  
Vol 56 (06) ◽  
pp. 77-85
Author(s):  
A. Joshi ◽  
◽  
H Bhojwani ◽  
U Joshi
Keyword(s):  
Crystal Structure ◽  
Virtual Screening ◽  
Crystal Structures ◽  
Active Site ◽  
Docking Studies ◽  
Cross Docking ◽  
Screening Protocol ◽  
Initial Crystal ◽  
Docking Accuracy ◽  
Selection Of

A total of 95 crystal structures of CDK2 were selected after considering criteria such as resolution and absence of missing residues in the active site; and subjected to cross-docking. 14 out of 95 crystal structures exhibited docking accuracy for greater than 70% of ligands at RMSD cut off 2Å in the cross- docking studies. These 14 crystal structures were selected for the second part of the study, which included validation using DUD sets and enrichment calculations. 8 out of 14 crystal structures possessed the enrichment factor of >10 at 1% of the ranked database. ROC-AUC, AUAC, RIE, and BEDROC were calculated for these 8 crystal structures. 2WXV produced maximum BEDROC (0.768, at α=8) and RIE (11.22). 2WXV as a single initial crystal structure in the virtual screening protocol is likely to produce more accurate results than any other single crystal structure.

scholarly journals Phase Behaviors of Ionic Liquids Heating from Different Crystal Polymorphs toward the Same Smectic-A Ionic Liquid Crystal by Molecular Dynamics Simulation

Crystals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 26 ◽  
Author(s):  
Wudi Cao ◽  
Yanting Wang
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Molecular Dynamics ◽  
Ionic Liquid ◽  
Liquid Crystal ◽  
Dynamics Simulation ◽  
Smectic A ◽  
Dynamics Simulations ◽  
Phase Behaviors ◽  
Initial Crystal

Five distinct crystal structures, based on experimental data or constructed manually, of ionic liquid [C14Mim][NO3] were heated in NPT molecular dynamics simulations under the same pressure such that they melted into the liquid crystal (LC) phase and then into the liquid phase. It was found that the more entropy-favored structure had a higher solid-LC transition temperature: Before the transition into the LC, all systems had to go through a metastable state with the side chains almost perpendicular to the polar layers. All those crystals finally melted into the same smectic-A LC structure irrelevant of the initial crystal structure.

scholarly journals THE EFFECT OF THE EXTERNAL MEDIUM ON THE STRUCTURAL-PHASE TRANSFORMATIONS OF QUARTZITE UPON HIGH-ENERGY ELECTRON IRRADIATION

2019 ◽  
pp. 30-34
Author(s):  
E.P. Bereznyak ◽  
I.V. Kolodiy ◽  
Yu.S. Khodyreva
Keyword(s):  
Crystal Structure ◽  
Electron Irradiation ◽  
Structural Phase ◽  
High Energy ◽  
Water Medium ◽  
X Ray Diffraction ◽  
Water Stream ◽  
Radiation Annealing ◽  
Initial Crystal ◽  
Structural Phase Transformations

The structural transformations of the natural quartzite under the electron irradiation in doses range of 107…108 Gy in various medium were studied using IR-spectroscopy, X-ray diffraction, and crystal-optical analyzes. It was established that under the irradiation, both in air and in a water stream, intense crystallization of the amorphous component occurs, which is siliceous cement. The initial crystal structure of quartzite is also improved as a result of radiation annealing of defects and impurities present in the initial quartz. It was found that the water medium significantly accelerates these processes, however, in the studied doses range for both types of irradiation, degradation of the quartzite crystal structure is not observed.

scholarly journals The first spontaneous resolution of a sulfoxide: Dianin's compound analogue, (R)-4-(4-hydroxyphenyl)-2,2,4-trimethylthiachroman-1-oxide

2018 ◽  
Vol 74 (11) ◽  
pp. 1633-1636
Author(s):  
James H. Gall ◽  
J. Derek White ◽  
David D. MacNicol ◽  
Christopher S. Frampton
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Crystal Structure Analysis ◽  
Spontaneous Resolution ◽  
Orthorhombic Space Group ◽  
Aromatic Substituent ◽  
Methyl Group ◽  
Dianin's Compound ◽  
Initial Crystal

The title sulfoxide, C18H20O2S, was prepared by controlled oxidation of thia-Dianin's compound using hydrogen peroxide in glacial acetic acid. On recrystallization from glacial acetic acid, it was found to form unsolvated, spontaneously resolved crystals, the initial crystal structure analysis revealing the presence of both sulfoxide epimers in the crystal. On multiple recrystallization a single epimer was observed, with crystallization occurring in the unchanged orthorhombic space group P212121, with Z′ = 1. The molecule possesses a distal conformation, referring to the juxtaposition of the p-hydoxyphenyl substituent with respect to its syn-related methyl group, with the sulfoxide oxygen atom anti to the aromatic substituent. The molecular packing features O—H...O hydrogen bond chains running parallel to the b axis of the unit cell.

Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

1977 ◽  
Vol 35 ◽  
pp. 24-25
Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Surface ◽  
Coherent Scattering ◽  
Crystal Structure Determination ◽  
Electron Diffraction Data ◽  
Polar Group ◽  
Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

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