Crystal Morphology as an Evidence of Supramolecular Organization in Adducts of 1,2-Bis(chloromercurio)tetrafluorobenzene with Organic Esters

2011 ◽  
Vol 11 (9) ◽  
pp. 3964-3978 ◽  
Author(s):  
Andrey A. Yakovenko ◽  
Jose H. Gallegos ◽  
Mikhail Yu. Antipin ◽  
Artem Masunov ◽  
Tatiana V. Timofeeva
Author(s):  
Joseph D. C. Peng

The relative intensities of the ED spots in a cross-grating pattern can be calculated using N-beam electron diffraction theory. The scattering matrix formulation of N-beam ED theory has been previously applied to imperfect microcrystals of gold containing stacking disorder (coherent twinning) in the (111) crystal plane. In the present experiment an effort has been made to grow single-crystalline, defect-free (111) gold films of a uniform and accurately know thickness using vacuum evaporation techniques. These represent stringent conditions to be met experimentally; however, if a meaningful comparison is to be made between theory and experiment, these factors must be carefully controlled. It is well-known that crystal morphology, perfection, and orientation each have pronounced effects on relative intensities in single crystals.The double evaporation method first suggested by Pashley was employed with some modifications. Oriented silver films of a thickness of about 1500Å were first grown by vacuum evaporation on freshly cleaved mica, with the substrate temperature at 285° C during evaporation with the deposition rate at 500-800Å/sec.


Author(s):  
U. Aebi ◽  
L.E. Buhle ◽  
W.E. Fowler

Many important supramolecular structures such as filaments, microtubules, virus capsids and certain membrane proteins and bacterial cell walls exist as ordered polymers or two-dimensional crystalline arrays in vivo. In several instances it has been possible to induce soluble proteins to form ordered polymers or two-dimensional crystalline arrays in vitro. In both cases a combination of electron microscopy of negatively stained specimens with analog or digital image processing techniques has proven extremely useful for elucidating the molecular and supramolecular organization of the constituent proteins. However from the reconstructed stain exclusion patterns it is often difficult to identify distinct stain excluding regions with specific protein subunits. To this end it has been demonstrated that in some cases this ambiguity can be resolved by a combination of stoichiometric labeling of the ordered structures with subunit-specific antibody fragments (e.g. Fab) and image processing of the electron micrographs recorded from labeled and unlabeled structures.


Author(s):  
Diogo Andrade ◽  
Talita Janaina Heller ◽  
Moisés Marcelino Neto ◽  
Cezar Otaviano Ribeiro Negrao

1981 ◽  
Vol 104 (2) ◽  
pp. 215-217
Author(s):  
Harald Schwarz ◽  
Heinz Follner
Keyword(s):  

Author(s):  
Ted Janssen ◽  
Gervais Chapuis ◽  
Marc de Boissieu

The law of rational indices to describe crystal faces was one of the most fundamental law of crystallography and is strongly linked to the three-dimensional periodicity of solids. This chapter describes how this fundamental law has to be revised and generalized in order to include the structures of aperiodic crystals. The generalization consists in using for each face a number of integers, with the number corresponding to the rank of the structure, that is, the number of integer indices necessary to characterize each of the diffracted intensities generated by the aperiodic system. A series of examples including incommensurate multiferroics, icosahedral crystals, and decagonal quaiscrystals illustrates this topic. Aperiodicity is also encountered in surfaces where the same generalization can be applied. The chapter discusses aperiodic crystal morphology, including icosahedral quasicrystal morphology, decagonal quasicrystal morphology, and aperiodic crystal surfaces; magnetic quasiperiodic systems; aperiodic photonic crystals; mesoscopic quasicrystals, and the mineral calaverite.


CrystEngComm ◽  
2021 ◽  
Author(s):  
Yanpeng Zhao ◽  
Guanwen Su ◽  
Guozhao Liu ◽  
Hongyuan Wei ◽  
Leping Dang

The effects of thirteen binary solvent systems on the growth of CL-20 were studied by molecular dynamics simulation, and the effect of antisolvent properties on the solvent inhibition was systematically investigated.


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