scholarly journals The Growth and Deformation of Ice Crystals

1954 ◽  
Vol 2 (16) ◽  
pp. 397-403 ◽  
Author(s):  
J. W. Glen ◽  
M. F. Perutz

AbstractX-ray diffraction photographs were taken of ice dendrites grown from water and from the vapour. In both cases [1120] was found to be the growth direction.A method of growing cylindrical single crystals of any desired orientation has been devised. Some of these crystals were extended to several times their original length. Slip took place exclusively on the basal plane. Experiments designed to locate the glide direction gave inconclusive results and suggested that, in general, crystals near the melting point can glide in any direction.Before deformation, ice crystals gave fairly sharp X-ray diffraction spots on Laue photographs. After deformation the spots are drawn out into streaks which later break up into rows of small spots. This indicates that bending of the crystals is followed by the formation of small crystallites of slightly differing orientations. Analogous effects are observed in metals.

1996 ◽  
Vol 11 (4) ◽  
pp. 804-812 ◽  
Author(s):  
Y. Namikawa ◽  
M. Egami ◽  
S. Koyama ◽  
Y. Shiohara ◽  
H. Kutami

Large YBa2Cu3O7−x (Y123) single crystals (larger than 13 mm cubed) have been grown along the c-axis reproducibly by the modified pulling method. The crystallinity of Y123 single crystal was investigated by x-ray diffraction and x-ray topography. Crystals grown from an MgO single crystal seed had some low angle subgrain boundaries which tilted 0.1–0.8° from each other. These grain boundaries originated from the seed crystal, and the subgrains were extended along the growth direction from the seed crystal. Y123 single crystals with no marked subgrains in the whole area were obtained by using Y123 single subgrain crystal seeds. FWHM of the x-ray rocking curve for the crystal so produced was about 0.14°, which was much better than the spectrum consisting of several separated peaks obtained from the previous crystals. Tc onset of the annealed sample was about 93.6 K, and the transition width was about 0.9 K. The low angle subgrain boundaries did not seem to be effective pinning centers for the magnetic flux.


1986 ◽  
Vol 77 ◽  
Author(s):  
C. J. Sparks ◽  
M. Hasaka ◽  
D. S. Easton ◽  
S. Baik ◽  
T. Habenschuss ◽  
...  

ABSTRACTThe perfection of epitaxial nickel films grown on the (00.ℓ) or basal plane of heated sapphire (A1203) single crystals were studied with X-ray diffraction techniques. Nickel films approximately 700 Å thick formed by vapor deposition increased in perfection as the temperature of the sapphire approached 1400°C. Although the nickel atom distances are 10.3% smaller than those of the closed-packed direction in sapphire, the strain was accommodated at the interface rather than being distributed through the thickness of the nickel film. Diffuse rods of X-ray scattering which are associated with diffraction from the interface gave information about the nature of the roughness at the interface.


1957 ◽  
Vol 35 (1) ◽  
pp. 38-47 ◽  
Author(s):  
G. B. Craig ◽  
B. Chalmers

The tensile plastic deformation of single-crystal and tricrystal specimens of zinc was investigated by analysis of the external change in shape of the specimens, and of the changes in X-ray diffraction patterns. It was demonstrated that the single crystals deformed by slip on the basal plane, but pyramidal as well as basal slip occurred in specimens containing grain boundaries.


2013 ◽  
Vol 46 (1) ◽  
pp. 276-278 ◽  
Author(s):  
B. Riscob ◽  
N. Vijayan ◽  
Mohd Shakir ◽  
M. A. Wahab ◽  
G. Bhagavannarayana

Good quality benzimidazole (BMZ) single crystals were successfully grown by the vertical Bridgman technique (VBT). The unavoidable thermal-induced structural grain boundaries formed in the normal VBT growth of these crystals with low melting point were controlled by using a double-wall ampoule. The grown single crystals were subjected to high-resolution X-ray diffraction to assess their crystallinity. The enhancement of optical properties due to the improvement in crystalline perfection is also reported.


2009 ◽  
Vol 615-617 ◽  
pp. 275-278 ◽  
Author(s):  
Justinas Palisaitis ◽  
Peder Bergman ◽  
P.O.Å. Persson

We have performed 2D X-ray diffraction mapping of the SiC lattice basal plane orientation over full 2” SiC substrates. Measurements of the omega angle were made in two perpendicular directions <11-20> and <1-100>, which gives the complete vectorized tilt of the basal planes. The Mapping revealed two characteristic bending behaviors on measured commercial wafers. The first is characterized by large variations in omega angle across the wafer in both crystallographic directions. The continuously changing omega angle in both directions gives the wafer an apparent rotationally symmetric bending which is concave towards the growth direction. The second characteristic behavior is seen in wafers with lower degree of omega angle variation. The variations in this type of wafers are not changing linearly, but are bending the basal planes with two-fold symmetry.


Author(s):  
Maciej Bujak ◽  
Marcin Podsiadło ◽  
Andrzej Katrusiak

Single crystals of isomeric 1,2,3-tribromobenzene (123TBB), 1,2,4-tribromobenzene (124TBB) and 1,3,5-tribromobenzene (135TBB) have been grown from different solvents and their structures determined by X-ray diffraction at 100, 200 and 270 K. The melting-point differences of ca 40 K between 135TBB, 123TBB and 124TBB have been correlated with the molecular symmetry and packing preferences in the crystal, as well as with the main types of intermolecular halogen interactions, i.e. Br...Br, Br...C (Br...π) and Br...H. The relationship between symmetry and melting point in Carnelley's rule has been extended to the accessibility of terminal atoms for the formation of intermolecular interactions, their occurrences and distribution, and the close packing. The electrostatic potential mapped on molecular surfaces demonstrates that in more symmetric molecules the more evenly distributed substituents are more accessible and form more optimum intermolecular interactions.


2000 ◽  
Vol 628 ◽  
Author(s):  
T.N. Blanton ◽  
D. Majumdar ◽  
S.M. Melpolder

ABSTRACTClay-polymer nanoparticulate composite materials are evaluated by the X-ray diffraction technique. The basal plane spacing provided information about the degree of intercalation and exfoliation of the 2: 1 layered clay structure. Both intercalation and exfoliation are controlled by the identity of the polymer and the clay:polymer ratio.


2019 ◽  
Author(s):  
Chem Int

Optically transparent single crystals of potassium acid phthalate (KAP, 0.5 g) 0.05 g and 0.1 g (1 and 2 mol %) trytophan were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X- ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by FTIR analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals. The thermal stability was evaluated by TG-DSC analysis.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4067
Author(s):  
Giovanni Ricci ◽  
Giuseppe Leone ◽  
Giorgia Zanchin ◽  
Benedetta Palucci ◽  
Alessandra Forni ◽  
...  

Some novel cobalt diphenylphosphine complexes were synthesized by reacting cobalt(II) chloride with (2-methoxyethyl)diphenylphosphine, (2-methoxyphenyl)diphenylphosphine, and 2-(1,1-dimethylpropyl)-6-(diphenylphosphino)pyridine. Single crystals suitable for X-ray diffraction studies were obtained for the first two complexes, and their crystal structure was determined. The novel compounds were then used in association with methylaluminoxane (MAO) for the polymerization of 1,3-butadiene, and their behavior was compared with that exhibited in the polymerization of the same monomer by the systems CoCl2(PnPrPh2)2/MAO and CoCl2(PPh3)2/MAO. Some significant differences were observed depending on the MAO/Co ratio used, and a plausible interpretation for such a different behavior is proposed.


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