scholarly journals Crystallographic Structure of Polycrystalline Ice

1978 ◽  
Vol 21 (85) ◽  
pp. 607-620 ◽  
Author(s):  
M. Matsuda ◽  
G. Wakahama
Keyword(s):  
Single Crystal ◽  
Great Majority ◽  
Mechanical Twinning ◽  
Boundary Structure ◽  
Crystallographic Structure ◽  
Oxygen Oxygen ◽  
Strong Shear ◽  
Polycrystalline Ice ◽  
Spatial Lattice ◽  
Glacier Ice

AbstractFor several types of polycrystalline ice of different origins, the spatial lattice orientation of each crystal was determined by measurements of both the a- and c-axis orientations. Analyses of the orientations of adjoining crystals showed that a great majority of adjoining crystals may be in a twinning relation. With special reference to the multi-maximum c-axis preferred-orientation fabric (the so-called “diamond pattern”), which is expected to occupy the largest part of a glacier ice mass, the crystal boundary structure was estimated. The preferred c-axis orientations of this fabric were explained as being the result of coincident oxygen-oxygen lines (hydrogen-bond lines) between adjoining crystals being concentrated in the orientations where seven oxygen-oxygen lines of one single crystal of ice are distributed. From the above result, it was concluded that the multi-maximum fabric is of the polycrystalline structure closest to the structure of a single crystal of ice among all the fabrics found in large ice masses.It is found that the occurrence, in glaciers and ice sheets, of a multi-maximum fabric has a bias to the parts which have undergone a strong shear deformation for a long time. It is thus suggested that plastic deformation of ice with this fabric may be attributed to mechanical twinning due to a strong shear stress.

Crystallographic Structure of Polycrystalline Ice

1978 ◽  
Vol 21 (85) ◽  
pp. 607-620 ◽  
Author(s):  
M. Matsuda ◽  
G. Wakahama
Keyword(s):  
Single Crystal ◽  
Great Majority ◽  
Mechanical Twinning ◽  
Boundary Structure ◽  
Crystallographic Structure ◽  
Oxygen Oxygen ◽  
Strong Shear ◽  
Polycrystalline Ice ◽  
Spatial Lattice ◽  
Glacier Ice

Abstract For several types of polycrystalline ice of different origins, the spatial lattice orientation of each crystal was determined by measurements of both the a- and c-axis orientations. Analyses of the orientations of adjoining crystals showed that a great majority of adjoining crystals may be in a twinning relation. With special reference to the multi-maximum c-axis preferred-orientation fabric (the so-called “diamond pattern”), which is expected to occupy the largest part of a glacier ice mass, the crystal boundary structure was estimated. The preferred c-axis orientations of this fabric were explained as being the result of coincident oxygen-oxygen lines (hydrogen-bond lines) between adjoining crystals being concentrated in the orientations where seven oxygen-oxygen lines of one single crystal of ice are distributed. From the above result, it was concluded that the multi-maximum fabric is of the polycrystalline structure closest to the structure of a single crystal of ice among all the fabrics found in large ice masses. It is found that the occurrence, in glaciers and ice sheets, of a multi-maximum fabric has a bias to the parts which have undergone a strong shear deformation for a long time. It is thus suggested that plastic deformation of ice with this fabric may be attributed to mechanical twinning due to a strong shear stress.

scholarly journals Determination of a-Axis Orientations of Polycrystalline Ice

1979 ◽  
Vol 22 (86) ◽  
pp. 165-169 ◽  
Author(s):  
Masuyoshi Matsuda
Keyword(s):  
Thin Section ◽  
Optical Measurement ◽  
Edge Length ◽  
Etch Pits ◽  
Axis Orientation ◽  
New Methods ◽  
Polycrystalline Ice ◽  
Glacier Ice ◽  
Oriented Parallel

AbstractTwo new methods have been devised for measurement of crystallographic lattice orientations of individual crystals in polycrystalline ice. The first uses edge-length ratios of etch pits. The second uses a combination of optical measurement on a thin section and etch-pit technique. Although the second method does not work for crystals with theirc-axis oriented parallel to the thin section, it is much simpler and more practical than the first method. When used on polycrystalline glacier ice, this method gave the threea-axes orientations as well asc-axis orientation for each crystal with an accuracy of 5°.

scholarly journals A digital workflow from crystallographic structure to single crystal particle attributes for predicting the formulation properties of terbutaline sulfate

CrystEngComm ◽  
2020 ◽  
Vol 22 (19) ◽  
pp. 3347-3360
Author(s):  
Thai T. H. Nguyen ◽  
Robert B. Hammond ◽  
Ioanna D. Styliari ◽  
Darragh Murnane ◽  
Kevin J. Roberts
Keyword(s):  
Surface Energy ◽  
Surface Chemistry ◽  
Single Crystal ◽  
Crystal Morphology ◽  
Crystal Surface ◽  
Drug Formulation ◽  
Crystallographic Structure ◽  
Terbutaline Sulfate ◽  
Crystal Particle ◽  
Ionic Addition

A detailed inter-molecular (synthonic) analysis of terbutaline sulfate, an ionic addition salt for inhalation drug formulation, is related to its crystal morphology, the surface chemistry of the habit faces and hence to its crystal surface energy.

scholarly journals Photoreversible interconversion of a phytochrome photosensory module in the crystalline state

2019 ◽  
Vol 117 (1) ◽  
pp. 300-307 ◽  
Author(s):  
E. Sethe Burgie ◽  
Jonathan A. Clinger ◽  
Mitchell D. Miller ◽  
Aaron S. Brewster ◽  
Pierre Aller ◽  
...  
Keyword(s):  
Single Crystal ◽  
Blue Light ◽  
Green Light ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Major Barrier ◽  
X Ray ◽  
Spectroscopic Analyses ◽  
Serial Femtosecond Crystallography

A major barrier to defining the structural intermediates that arise during the reversible photointerconversion of phytochromes between their biologically inactive and active states has been the lack of crystals that faithfully undergo this transition within the crystal lattice. Here, we describe a crystalline form of the cyclic GMP phosphodiesterases/adenylyl cyclase/FhlA (GAF) domain from the cyanobacteriochrome PixJ inThermosynechococcus elongatusassembled with phycocyanobilin that permits reversible photoconversion between the blue light-absorbing Pb and green light-absorbing Pg states, as well as thermal reversion of Pg back to Pb. The X-ray crystallographic structure of Pb matches previous models, including autocatalytic conversion of phycocyanobilin to phycoviolobilin upon binding and its tandem thioether linkage to the GAF domain. Cryocrystallography at 150 K, which compared diffraction data from a single crystal as Pb or after irradiation with blue light, detected photoconversion product(s) based on Fobs− Fobsdifference maps that were consistent with rotation of the bonds connecting pyrrole rings C and D. Further spectroscopic analyses showed that phycoviolobilin is susceptible to X-ray radiation damage, especially as Pg, during single-crystal X-ray diffraction analyses, which could complicate fine mapping of the various intermediate states. Fortunately, we found that PixJ crystals are amenable to serial femtosecond crystallography (SFX) analyses using X-ray free-electron lasers (XFELs). As proof of principle, we solved by room temperature SFX the GAF domain structure of Pb to 1.55-Å resolution, which was strongly congruent with synchrotron-based models. Analysis of these crystals by SFX should now enable structural characterization of the early events that drive phytochrome photoconversion.

Electric field-induced crack growth and domain-structure evolution for [100]- and [101]-oriented 72%Pb(Mg1/3Nb2/3) O3–28%PbTiO3 ferroelectric single crystals

2008 ◽  
Vol 23 (12) ◽  
pp. 3387-3395 ◽  
Author(s):  
F. Fang ◽  
W. Yang ◽  
F.C. Zhang ◽  
H. Qing
Keyword(s):  
Electric Field ◽  
Crack Propagation ◽  
Single Crystal ◽  
Single Crystals ◽  
Crack Growth ◽  
Domain Structure ◽  
Boundary Structure ◽  
Structure Evolution ◽  
In Situ Observation ◽  
Oriented Single Crystal

In situ observation of the electrically induced crack growth and domain-structure evolution is carried out for [100]- and [101]-oriented 72%Pb(Mg1/3Nb2/3)O3–28% PbTiO3 (PMN–PT 72/28) ferroelectric single crystals under static (poling) and alternating electric fields. On the same poling electric field, domains are in the stable engineered domain state where four equivalent polarization variants coexist for [100]-oriented single crystal, while parallel lines representing the 71° domain boundaries appear for [101]-oriented one. Under the same cyclic electric field, the [100]-oriented single crystal shows much higher crack propagation resistance than that of a [101]-oriented crystal. Apart from the material aspects, such as crystallographic fracture anisotropy and non-180° domain boundary structure, crack boundary condition plays an important role in determining the crack propagation behavior.

Mechanical twinning in stoichiometric lithium niobate single crystal

1997 ◽  
Vol 180 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Bong Mo Park ◽  
Kenji Kitamura ◽  
Kazuya Terabe ◽  
Yasunori Furukawa ◽  
Yangyang Ji ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Single Crystal ◽  
Mechanical Twinning ◽  
Lithium Niobate Single Crystal

A Highly Reliable Al Line with Controlled Texture and Grain Boundaries

1995 ◽  
Vol 391 ◽  
Author(s):  
M. Hasunuma ◽  
H. Toyoda ◽  
T. Kawanoue ◽  
S. Ito ◽  
H. Kaneko ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Single Crystal ◽  
Grain Boundaries ◽  
Empirical Relation ◽  
Boundary Structure ◽  
Homogeneous Microstructure ◽  
Grain Boundary Structure ◽  
Dislocation Arrays ◽  
Order Of Magnitude ◽  
Individual Grains

AbstractIn order to clarify the relationship between Al line reliability and film microstructure, especially grain boundary structure and crystal texture, we have tested three kinds of highly textured Al lines, namely, single-crystal Al line, quasi-single-crystal Al line and hypertextured Al line, and two kinds of conventional Al lines deposited on TiN/Ti and on SiO2. Consequently, the empirical relation between the electromigration (EM) lifetime of Al line † and the (111) full width at half maximum (FWHM) value ω is described by † ∝ ω-2 [1]. This improvement of Al line reliability results from as following reasons; firstly, homogeneous microstructure and high activation energy of 1.28eV for the single-crystal Al line (ω=0.18°); secondly, sub-grain boundaries which consisted of dislocation arrays found in the quasi-single-crystal Al line (ω=0.26°) has turned out to be no more effective mass transport paths because dislocation lines are perpendicular to the direction of electron wind. Although there exist plural grain boundary diffusion paths in the newly developed hypertextured Al line (ω=0.5°) formed by using an amorphous Ta-Al underlayer {1], the vacancy flux along the line has been suppressed to the same order of magnitude of single crystal line. It has been clarified that the decrease of FWHM value has promoted the formation of sub-grain boundaries and low-angle boundaries with detailed orientation analysis of individual grains in the hypertextured film. The longer EM lifetime for the hypertextured Al line is considered to be due to the small grain boundary diffusivities for these stable grain boundaries, and this diffusivity reduction resulted in the suppression of void/hillock pair in the Al lines. These results have confirmed that controlling texture and/or grain boundary itself is a promising approach to develop reliable Al lines which withstand higher current densities required in future ULSIs.

Crystallographic structure and elastic measurements of La2−xSrxCuO4 single crystal

1991 ◽  
Vol 77 (12) ◽  
pp. 945-948 ◽  
Author(s):  
M. Slaski ◽  
O. Steinsvoll ◽  
E.J. Samuelsen ◽  
O-M. Nes ◽  
Wu Ting ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystallographic Structure

scholarly journals On the Significance of Normal Stress Effects in the Flow of Glaciers

1987 ◽  
Vol 33 (115) ◽  
pp. 268-273 ◽  
Author(s):  
Chi-Sing Man ◽  
Quan-Xin Sun
Keyword(s):  
Normal Stress ◽  
Creep Behaviour ◽  
Laboratory Data ◽  
Constitutive Models ◽  
Second Order ◽  
Material Parameters ◽  
Stress Effects ◽  
Polycrystalline Ice ◽  
Glacier Ice ◽  
Flow Law

AbstractMcTigue and others (1985) identified a possible problem in the type of constitutive equation usually used for modeling the creep behaviour of polycrystalline ice. They pointed out that Glen’s flow law necessarily excludes the consideration of normal stress effects, which are of great significance in other disciplines that consider non-Newtonian fluids. Using the second-order fluid (with material parameters evaluated from laboratory data) as a tentative model for ice, they reached the conclusion that normal stress effects may be discernible in natural glacier flow. But, as noted by McTigue and others, the second-order fluid “fails to represent the non-linear rate dependence of ice in shear”; therefore it is in fact not a suitable constitutive model for glacier ice in shearing flow. In this note, parallel to what McTigue and others did for the second-order fluid, we present a similar analysis for (I) the modified second-order fluid and (II) the power-law fluid of grade 2, both of which are constitutive models recently proposed by Man as a tentative generalization of Glen’s flow law. Both models (I) and (II) can represent normal stress effects, and both agree with Glen’s flow law in the prediction of the depth profile of velocity in the steady laminar flow of glaciers. For ease of comparison, the same creep data of McTigue and others are used in quantifying the material parameters in these two models. Both models (I) and (II) predict far less pronounced normal stress effects in glaciers than those estimated by McTigue and others (whose data analysis in fact suffered from inconsistencies and over-parameterization).

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