Growth mechanisms of NaClO3 and KBr from aqueous solutions under relatively high supersaturation ranges

The results of the effect of the growth history on Potassium Dihydrogen Phosphate (KDP) crystals growth mechanism are presented in the paper. Crystals were grown in temperature range of from aqueous solutions, saturated at . Two types of the experiments were performed. In both types, after the nucleation at crystals were grown at the same temperature for about 1.5 hour and then dissolved at temperature for about 15 min. After refaceting, in the first type, the crystal growth started at , followed by the temperature increasing in steps of to . In the second type, after refaceting the crystal growth started at , followed by the temperature decreasing in steps of to . Obtained results indicate that KDP crystals growth mechanisms do not depend on growth history. They are discussed in accordance with the current theories.

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Heat and Mass Transfer Effects on Ice Growth Mechanisms in Pure Water and Aqueous Solutions

Crystal Growth & Design ◽

10.1021/cg401428v ◽

2013 ◽

Vol 14 (1) ◽

pp. 389-395 ◽

Cited By ~ 12

Author(s):

Michael Kapembwa ◽

Marcos Rodríguez-Pascual ◽

Alison E. Lewis

Keyword(s):

Mass Transfer ◽

Aqueous Solutions ◽

Heat And Mass Transfer ◽

Pure Water ◽

Growth Mechanisms ◽

Transfer Effects ◽

Ice Growth

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Ultrathin frozen sections of yeast without aldehyde prefixation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081152 ◽

1978 ◽

Vol 36 (2) ◽

pp. 58-59

Author(s):

K. J. Böhm ◽

a. E. Unger

Keyword(s):

Aqueous Solutions ◽

Biological Material ◽

Yeast Cells ◽

Frozen Sections ◽

Good Preservation ◽

Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

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The growth of mica polytypes as studied by conventional and high-resolution TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074690 ◽

1983 ◽

Vol 41 ◽

pp. 174-177

Author(s):

A. Baronnet ◽

M. Amouric

Keyword(s):

Water Pressure ◽

Point Of View ◽

Temperature Fields ◽

Natural Occurrence ◽

Growth Mechanisms ◽

Long Period ◽

High Resolution Tem ◽

Layer Stacking ◽

Experimental Works ◽

Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

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Crystal structure images of large gold clusters and growing crystals by HRTEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011218x ◽

1984 ◽

Vol 42 ◽

pp. 428-429

Author(s):

L.R. Wallenberg ◽

J.-O. Bovin ◽

G. Schmid

Keyword(s):

Crystal Structure ◽

Nucleation And Growth ◽

Close Packing ◽

Gold Clusters ◽

Molecular Weight Determination ◽

Growth Mechanisms ◽

Starting Point ◽

Different Types ◽

Nucleation And Growth Mechanisms ◽

Points Of View

Metallic clusters are interesting from various points of view, e.g. as a mean of spreading expensive catalysts on a support, or following heterogeneous and homogeneous catalytic events. It is also possible to study nucleation and growth mechanisms for crystals with the cluster as known starting point.Gold-clusters containing 55 atoms were manufactured by reducing (C6H5)3PAuCl with B2H6 in benzene. The chemical composition was found to be Au9.2[P(C6H5)3]2Cl. Molecular-weight determination by means of an ultracentrifuge gave the formula Au55[P(C6H5)3]Cl6 A model was proposed from Mössbauer spectra by Schmid et al. with cubic close-packing of the 55 gold atoms in a cubeoctahedron as shown in Fig 1. The cluster is almost completely isolated from the surroundings by the twelve triphenylphosphane groups situated in each corner, and the chlorine atoms on the centre of the 3x3 square surfaces. This gives four groups of gold atoms, depending on the different types of surrounding.

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A TEM study of the microstructure of avian eggshells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130146 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1102-1103

Author(s):

S. Q. Xiao ◽

S. Baden ◽

A. H. Heuer

Keyword(s):

Electron Microscope ◽

Calcium Carbonate ◽

Nucleation And Growth ◽

Growth Mechanisms ◽

Shell Surface ◽

Thin Sections ◽

Polycrystalline Metals ◽

Transmission Electron ◽

Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

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Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152136 ◽

1989 ◽

Vol 47 ◽

pp. 32-33

Author(s):

S.A.C. Gould ◽

B. Drake ◽

C.B. Prater ◽

A.L. Weisenhorn ◽

S.M. Lindsay ◽

...

Keyword(s):

Amino Acids ◽

Dna Sequencing ◽

Aqueous Solutions ◽

Atomic Force Microscope ◽

Piezoelectric Crystal ◽

Atomic Force ◽

Structure Of Molecules ◽

Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

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