Orthorhombic crystal structure of the A-DNA octamer d(GTACGTAC). Comparison with the tetragonal structure

1993 ◽  
Vol 213 (2) ◽  
pp. 673-682 ◽  
Author(s):  
Beatrice LANGLOIS d'ESTAINTOT ◽  
Alain DAUTANT ◽  
Christian COURSEILLE ◽  
Gilles PRECIGOUX
Keyword(s):  
Crystal Structure ◽  
Tetragonal Structure ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure

STUDY ON THE SUPERCONDUCTIVITY OF Ba2(Y1−xLax)Cu3O7−y

1988 ◽  
Vol 02 (03n04) ◽  
pp. 621-628
Author(s):  
C. DONG ◽  
J.K. LIANG ◽  
C.G. CUI ◽  
S.L. LI ◽  
Y.M. NI ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Continuous Solid Solution ◽  
Mixed Valence ◽  
Tetragonal Structure ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Semiconductor Behavior ◽  
Low Dimensional

A series of samples with the nominal composition Ba 2( Ba 1−x La x) Cu 3 O 7−y, (0≤x≤1), was synthesized by solid state reaction. An X-ray diffraction study showed that a continuous solid solution exists between Ba 2 YCu 3 O 7−y and Ba 2 LaCu 3 O 7−y and there is a composition induced order-disorder transition from an orthorhombic to a tetragonal structure when x value is near 0.9. All the samples with orthorhombic crystal structure are superconductors with Tc onset above 90K. The transition midpoint temperature decreases smoothly when La content increases. The samples with x≥0.9 have a tetragonal structure and show semiconductor behavior with an exception of the x=1.0 sample which is a superconductor. Based on our previous and present studies, we concluded that the low dimensional character of the crystal structure and the mixed-valence state of copper or oxygen are necessary conditions for high-Tc superconductivity in copper-containing oxides.

Growth, Microstructure and Properties of Epitaxial La1-XSrxMnO3 Thin Films on Various Substrates Using RF Magnetron Sputtering

2011 ◽  
Vol 14 ◽  
pp. 83-92 ◽  
Author(s):  
Y. Fang ◽  
V.R. Sakhalkar ◽  
J. He ◽  
H.Q. Jiang ◽  
Jiechao Jiang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Magnetron Sputtering ◽  
Bulk Material ◽  
Rf Magnetron Sputtering ◽  
Tetragonal Structure ◽  
Magnetic Studies ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Mgo Substrate

Synthesis of high quality epitaxial LaMnO3 and (La,Sr)MnO3 films on large areas is highly desirable. Recently, we have deposited LaMnO3 and (La,Sr)MnO3 films on the MgO (001) and LaAlO3 (001) substrates using RF magnetron sputtering. Highly epitaxial quality thin films have been successfully obtained at 750 °C by manipulating processing parameters as characterized by X-ray diffraction, electron diffraction and HRTEM. The epitaxial LaMnO3 and (La,Sr)MnO3 thin films have either a tetragonal or orthorhombic crystal structure depending on the film (target) composition and substrate type. The (La,Sr)MnO3 films were found to have an orthorhombic crystal structure when deposited on LaAlO3 substrate and a tetragonal structure when deposited on MgO substrate; whereas LaMnO3 films have a tetragonal structure when deposited on LaAlO3 substrate and an orthorhombic crystal structure when deposited on MgO substrate. The orthorhombic structures of the (La,Sr)MnO3 film on LaAlO3 and LaMnO3 on MgO are oriented with their c-axis on the film plane. Magnetic studies show that the epitaxial films have higher phase transition temperature than the corresponding bulk material and to those obtained using pulse laser deposition. Successful synthesis of highly epitaxial quality films by RF magnetron sputtering over a larger area can result in reduced cost for fabricating and processing epitaxial thin films.

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

scholarly journals Crystal Structures of New Ivermectin Pseudopolymorphs

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 172
Author(s):  
Kirill Shubin ◽  
Agris Bērziņš ◽  
Sergey Belyakov
Keyword(s):  
Crystal Structure ◽  
Molecular Conformation ◽  
Methyl Tert Butyl Ether ◽  
Minor Role ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Monoclinic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
Structure Space

New pseudopolymorphs of ivermectin (IVM), a potential anti-COVID-19 drug, were prepared. The crystal structure for three pseudopolymorphic crystalline forms of IVM has been determined using single-crystal X-ray crystallographic analysis. The molecular conformation of IVM in crystals has been compared with the conformation of isolated molecules modeled by DFT calculations. In a solvent with relatively small molecules (ethanol), IVM forms monoclinic crystal structure (space group I2), which contains two types of voids. When crystallized from solvents with larger molecules, like γ-valerolactone (GVL) and methyl tert-butyl ether (MTBE), IVM forms orthorhombic crystal structure (space group P212121). Calculations of the lattice energy indicate that interactions between IVM and solvents play a minor role; the main contribution to energy is made by the interactions between the molecules of IVM itself, which form a framework in the crystal structure. Interactions between IVM and molecules of solvents were evaluated using Hirshfeld surface analysis. Thermal analysis of the new pseudopolymorphs of IVM was performed by differential scanning calorimetry and thermogravimetric analysis.

scholarly journals (R)-Baclofen [(R)-4-amino-3-(4-chlorophenyl)butanoic acid]

2022 ◽  
Vol 78 (1) ◽  
Author(s):  
Feodor Belov ◽  
Alexander Villinger ◽  
Jan von Langermann
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Title Compound ◽  
Single Crystal Xrd ◽  
Butanoic Acid ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
Structure Space

This article provides the first single-crystal XRD-based structure of enantiopure (R)-baclofen (form C), C10H12ClNO2, without any co-crystallized substances. In the enantiopure title compound, the molecules arrange themselves in an orthorhombic crystal structure (space group P212121). In the crystal, strong hydrogen bonds and C—H ... Cl bonds interconnect the zwitterionic molecules.

Thermal enhancement of 2H11/2→4I15/2 up-conversion luminescence of Er3+ doped K2Yb(PO4)(MoO4) phosphors

2021 ◽  
Author(s):  
Hongqiang Cui ◽  
Yongze Cao ◽  
Lei Zhang ◽  
Yuhang Zhang ◽  
Siying Ran ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Reaction Method ◽  
X Ray ◽  
Thermal Enhancement

Er3+ with different concentrations doped K2Yb(PO4)(MoO4) phosphors were prepared by a solid-state reaction method, and the layered orthorhombic crystal structure of the samples was confirmed by X-ray diffraction (XRD). Under...

Influence of Deposition Time on the Properties of Highly-Oriented SnS Thin Films Prepared Using the Thermal Evaporation Method

2012 ◽  
Vol 602-604 ◽  
pp. 1409-1412 ◽  
Author(s):  
Patrick. A. Nwofe ◽  
K. T. Ramakrishna Reddy ◽  
Robert W. Miles
Keyword(s):  
Crystal Structure ◽  
Single Phase ◽  
Deposition Time ◽  
Thermal Evaporation ◽  
Atomic Ratio ◽  
Energy Band Gap ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Thermal Evaporation Method ◽  
Sns Thin Films

The influence of deposition time on the properties of SnS films grown using the thermal evaporation was reported. The deposition time was varied between 0.7 – 3 min, keeping other deposition variables constant. The layers showed single phase with orthorhombic crystal structure, exhibiting a strong (040) reflection. With an increase of deposition time, the Sn/S atomic ratio and grain size and the number of crystallites in the layers increased while the dislocation density and bulk resistivity decreased. The increase of crystallinity of the layers was confirmed by the change of strain from tensile to compressive with increasing deposition time. The transmittance of the films were > 70% for deposition time ≤ 1min and decreased drastically otherwise. The energy band gap varied in the range 1.80 - 1.30 eV with the lower values obtained at longer deposition times.

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