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Journal articles on the topic 'CaIrO3'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Boffa Ballaran, Tiziana, Kanchana Kularatne, and Reidar Trønnes. "High-pressure structural behaviour of CaIrO3polymorphs." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C267. http://dx.doi.org/10.1107/s2053273314097320.

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The two known polymorphs of CaIrO3 crystallize int the orthorhombic space groups Pbnm and Cmcm. These compounds have been the focus of much research in the Earth sciences community because they are isostructural with MgSiO3 perovskite and post-perovskite structures which are likely the most abundant minerals in the Earth's lower mantle. CaIrO3 post-perovskite is stable at ambient conditions and transforms at 1-3 GPa and at temperatures above 13500C to the CaIrO3 perovskite structure providing an ideal low pressure and low temperature analogue for the MgSiO3 perovskite to post-perovskite phase transformation which occurs at the extreme conditions of 125 GPa and 2500 K. However, in order to assess whether the CaIrO3 compounds can be used as analogues of MgSiO3 phases, a correct knowledge of their atomic structures and their response to changes in pressure and temperature is essential. In this study the structural behavior of both CaIrO3 polymorphs has been investigated using single-crystal X-ray diffraction at different pressures up to 10 GPa. The orthorhombic distortion of CaIrO3 perovskite derives from the cubic perovskite aristotype by tilting of the octahedral units. These tilts are very large and their variation with pressure is clearly different from the tilting reported for other Ca-oxide perovskites giving rise to a much stiffer structure. The CaIrO3 post-perovskite phase has a layered structure consisting of alternating sheets of Ca atoms and distorted IrO6 octahedra which share edges to form rows running parallel to [100]. With increasing pressure the octahedral tilting remains practically constant and compression of the post-perovskite structure occurs as a result of compression of Ca layers. With increasing temperature, instead, the octahedral tilting increases giving rise to smaller distances between oxygens of adjacent octahedra whose repulsion likely causes the transformation to the CaIrO3 perovskite structure.

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OHGUSHI, Kenya, Hiroyuki OHSUMI, Jun-ichi YAMAURA, and Taka-hisa ARIMA. "Magnetic Structure of Post-Perovskite Compound CaIrO3." Nihon Kessho Gakkaishi 56, no. 1 (2014): 36–42. http://dx.doi.org/10.5940/jcrsj.56.36.

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3

Sugahara, M., A. Yoshiasa, A. Yoneda, et al. "Single-crystal X-ray diffraction study of CaIrO3." American Mineralogist 93, no. 7 (2008): 1148–52. http://dx.doi.org/10.2138/am.2008.2701.

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4

Liu, Wei, Matthew L. Whitaker, Qiong Liu, et al. "Thermal equation of state of CaIrO3 post-perovskite." Physics and Chemistry of Minerals 38, no. 5 (2011): 407–17. http://dx.doi.org/10.1007/s00269-010-0414-z.

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5

Ono, S. "Physics and chemistry of CaIrO3-type postperovskite phase." Geochimica et Cosmochimica Acta 70, no. 18 (2006): A459. http://dx.doi.org/10.1016/j.gca.2006.06.924.

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6

Hustoft, J., S. H. Shim, A. Kubo, and N. Nishiyama. "Raman spectroscopy of CaIrO3 postperovskite up to 30 GPa." American Mineralogist 93, no. 10 (2008): 1654–58. http://dx.doi.org/10.2138/am.2008.2938.

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7

Singh, Vijeta, and J. J. Pulikkotil. "Post-perovskite CaIrO3: a conventional Slater type antiferromagnetic insulator." Physical Chemistry Chemical Physics 18, no. 37 (2016): 26300–26305. http://dx.doi.org/10.1039/c6cp05026c.

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To resolve the controversy of whether or not the origin of an electronic gap in antiferromagnetic post-perovskite (pPv) CaIrO<sub>3</sub> is due to Coulomb repulsion or spin–orbit coupling, and/or both, we have performed comprehensive full potential density functional theory based calculations.

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8

KEAWPRAK, Nittaya, Rong TU, and Takashi GOTO. "Thermoelectricity of CaIrO3 ceramics prepared by spark plasma sintering." Journal of the Ceramic Society of Japan 117, no. 1364 (2009): 466–69. http://dx.doi.org/10.2109/jcersj2.117.466.

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9

Hirai, Daigorou, Jobu Matsuno, Daisuke Nishio-Hamane, and Hidenori Takagi. "Semimetallic transport properties of epitaxially stabilized perovskite CaIrO3 films." Applied Physics Letters 107, no. 1 (2015): 012104. http://dx.doi.org/10.1063/1.4926723.

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10

Gunasekera, J., Y. Chen, J. W. Kremenak, P. F. Miceli, and D. K. Singh. "Mott insulator-to-metal transition in yttrium-doped CaIrO3." Journal of Physics: Condensed Matter 27, no. 5 (2015): 052201. http://dx.doi.org/10.1088/0953-8984/27/5/052201.

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11

Niwa, Ken, Takehiko Yagi, and Kenya Ohgushi. "Elasticity of CaIrO3 with perovskite and post-perovskite structure." Physics and Chemistry of Minerals 38, no. 1 (2010): 21–31. http://dx.doi.org/10.1007/s00269-010-0378-z.

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12

Crichton, W. A., F. L. Bernal, J. Guignard, M. Hanfland, and S. Margadonna. "Observation of Sb2S3-type post-post-perovskite in NaFeF3. Implications for ABX3 and A2X3 systems at ultrahigh pressure." Mineralogical Magazine 80, no. 4 (2016): 659–74. http://dx.doi.org/10.1180/minmag.2016.080.017.

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AbstractWe describe the structures and transformations that lead to the crystallization of a post-post-perovskite of Sb2S3 type in a GdFeO3-type fluoroperovskite system at high-pressure conditions, through use of large-volume powder and single-crystal x-ray diffraction techniques. The results of this analysis gives unique access to the relative crystallographic orientations of all the polymorphs encountered (GdFeO3 type, CaIrO3 type and Sb2S3 type). We use this information to extend this description to include other calculated and observed forms that are competitive in ABX3 and A2X3 stoichiometries (e.g. α-Gd2S3 and Be3N2 types) and provide substantial information on inter-relationships between these structures. Such information is critical to the interpretation of transition mechanisms, predicting transition sequences and to the expression of directional properties in those transformed structures. The transformation from CaIrO3 type to Sb2S3 type is group-subgroup, from Cmcm with fc2a, to Pnma c5, with no observable volume change, but considerable change to the morphology of the lattice. There is a concomitant increase in coordination and average bond length compared to the post-perovskite form of NaFeF3.

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13

Lindsay-Scott, Alex, Ian G. Wood, and David P. Dobson. "Thermal expansion of CaIrO3 determined by X-ray powder diffraction." Physics of the Earth and Planetary Interiors 162, no. 1-2 (2007): 140–48. http://dx.doi.org/10.1016/j.pepi.2007.04.003.

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14

Ballaran, T. B., R. G. Tronnes, and D. J. Frost. "Equations of state of CaIrO3 perovskite and post-perovskite phases." American Mineralogist 92, no. 10 (2007): 1760–63. http://dx.doi.org/10.2138/am.2007.2715.

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15

Martin, C. David. "The local post-perovskite structure and its temperature dependence: atom-pair distances in CaIrO3revealed through analysis of the total X-ray scattering at high temperatures." Journal of Applied Crystallography 41, no. 4 (2008): 776–83. http://dx.doi.org/10.1107/s0021889808019365.

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The temperature-dependent post-perovskite structure model of MgSiO3is reinvestigated through analysis of the atom-pair distances observed experimentallyviaFourier transformation of X-ray diffraction and diffuse scattering, the total X-ray scattering, from CaIrO3. In contrast to the results of a previous Rietveld structure refinement, which shows a negative or null thermal expansion of Ir—O and Ca—O bond lengths within the average long-range structure, visual inspection of these atom-pair distances in the pair-distribution function, in addition to structure models fitted through least-squares refinement to this local-structure data, strongly suggests that these distances between atom pairs increase with temperature. The average long-range structure of CaIrO3, visible from Rietveld structure refinement, is distinct from the short-range structure (≤ 18 Å) at all of the temperatures examined in this study (325–1114 K) and is reproduced in structure models fitted to the pair-distribution function extending to sufficiently long atom-pair distances (≥ 50 Å). While previous data obtained with Rietveld structure refinement show the iridium coordination octahedra to distort with increasing temperature, models of the short-range structure demonstrate that these polyhedra instead reduce distortion and rotate in a manner similar to that occurring in the perovskite structure.

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16

Hunt, Simon A., Andrew M. Walker, and Elisabetta Mariani. "In-situ measurement of texture development rate in CaIrO3 post-perovskite." Physics of the Earth and Planetary Interiors 257 (August 2016): 91–104. http://dx.doi.org/10.1016/j.pepi.2016.05.007.

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17

Ono, S. "Equation of state of CaIrO3-type MgSiO3 up to 144 GPa." American Mineralogist 91, no. 2-3 (2006): 475–78. http://dx.doi.org/10.2138/am.2006.2118.

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18

Biswas, Abhijit, and Yoon Hee Jeong. "Persistent semi-metal-like nature of epitaxial perovskite CaIrO3 thin films." Journal of Applied Physics 117, no. 19 (2015): 195305. http://dx.doi.org/10.1063/1.4921460.

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19

Aguado, F., S. Hirai, S. A. T. Redfern, and R. I. Smith. "Thermal expansion of CaIrO3 post-perovskite determined by time-of-flight measurements." Journal of Physics: Conference Series 549 (November 17, 2014): 012024. http://dx.doi.org/10.1088/1742-6596/549/1/012024.

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20

Negishi, Masamichi, Naoka Hiraoka, Daisuke Nishio-Hamane, and Hidenori Takagi. "Contrasted Sn substitution effects on Dirac line node semimetals SrIrO3 and CaIrO3." APL Materials 7, no. 12 (2019): 121101. http://dx.doi.org/10.1063/1.5129235.

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21

Kojitani, H., A. Furukawa, and M. Akaogi. "Thermochemistry and high-pressure equilibria of the post-perovskite phase transition in CaIrO3." American Mineralogist 92, no. 1 (2007): 229–32. http://dx.doi.org/10.2138/am.2007.2358.

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22

Inaguma, Yoshiyuki, Ken-ichiro Hasumi, Masashi Yoshida, Tomonori Ohba, and Tetsuhiro Katsumata. "High-Pressure Synthesis, Structure, and Characterization of a Post-perovskite CaPtO3with CaIrO3-Type Structure." Inorganic Chemistry 47, no. 6 (2008): 1868–70. http://dx.doi.org/10.1021/ic701851e.

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23

De Vero, J. C., I. Hwang, A. C. L. Santiago та ін. "Growth of Bi2Sr2CaCu2O8+δ thin films with enhanced superconducting properties by incorporating CaIrO3 nanoparticles". Applied Physics Letters 104, № 17 (2014): 172603. http://dx.doi.org/10.1063/1.4874333.

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24

Berryman, James G. "Computing elastic constants for random polycrystals of orthotropic MgSiO3, related polymorphs, and CaIrO3 analogs." Journal of Computational Physics 271 (August 2014): 379–96. http://dx.doi.org/10.1016/j.jcp.2013.06.038.

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25

Martin, C. D., K. W. Chapman, P. J. Chupas, et al. "Compression, thermal expansion, structure, and instability of CaIrO3, the structure model of MgSiO3 post-perovskite." American Mineralogist 92, no. 7 (2007): 1048–53. http://dx.doi.org/10.2138/am.2007.2473.

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26

Masuko, M., J. Fujioka, M. Nakamura, M. Kawasaki, and Y. Tokura. "Strain-engineering of charge transport in the correlated Dirac semimetal of perovskite CaIrO3 thin films." APL Materials 7, no. 8 (2019): 081115. http://dx.doi.org/10.1063/1.5109582.

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27

Niwa, Ken, Takehiko Yagi, Kenya Ohgushi, Sébastien Merkel, Nobuyoshi Miyajima, and Takumi Kikegawa. "Lattice preferred orientation in CaIrO3 perovskite and post-perovskite formed by plastic deformation under pressure." Physics and Chemistry of Minerals 34, no. 9 (2007): 679–86. http://dx.doi.org/10.1007/s00269-007-0182-6.

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28

Bykova, Elena, Maxim Bykov, Vitali Prakapenka, et al. "High-pressure behavior of Fe2O3." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C49. http://dx.doi.org/10.1107/s2053273314099501.

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High pressure behavior of Fe2O3has been a long-standing subject of research due to its high importance for understanding Earth's interiors. At pressures from 40 to 60 GPa it undergoes a series of transformations, such as structural changes with a large volume discontinuity (~10 %), a drop of the resistivity, a spin crossover of Fe3+, and a disappearance of the ordered magnetic state. The crystal structure of the phase(s) observed on compression at ambient temperature above 50 GPa is still under question since only powder X-ray diffraction (XRD) data were available so far. Mössbauer and Raman spectroscopy studies cannot provide definitive structural information. Applying laser heating to Fe2O3, compressed up to 70 GPa and above, results in a distinct reconstructive phase transition to the CaIrO3-type structure, according to powder XRD. Poverty of the available structural data encouraged us to perform a series of high-pressure and high-temperature XRD experiments on single crystals of Fe2O3in diamond anvil cells. We have studied the behavior of Fe2O3at pressures up to 100 GPa and temperatures up to 2500 K. Here we report crystal structures of two novel high-pressure Fe2O3polymorphs, as well as the relations between a spin state of iron atoms and the crystal chemistry of the iron compound. In our compression experiments initially hematite-structured Fe2O3transformed to a new phase at ~54 GPa with 10 % of the volume reduction. This phase has a triclinic distorted perovskite-type structure. The second reconstructive transition occurred at 66–70 GPa with 3 % of the volume discontinuity and resulted in formation of an orthorhombic phase. Laser heating to ~21001100 K at pressures above 70 GPa promoted a transition to a Cmcm CaIrO3-type phase, whose crystal structure was refined by means of single crystal XRD to R1~ 9.7 %. Decompression experiments showed that the Cmcm phase transforms back to hematite at pressures between ~25 and 15 GPa.

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29

Miyagi, Lowell, Norimasa Nishiyama, Yanbin Wang, et al. "Deformation and texture development in CaIrO3 post-perovskite phase up to 6 GPa and 1300 K." Earth and Planetary Science Letters 268, no. 3-4 (2008): 515–25. http://dx.doi.org/10.1016/j.epsl.2008.02.005.

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30

Yoshino, Takashi, and Daisuke Yamazaki. "Grain growth kinetics of CaIrO3 perovskite and post-perovskite, with implications for rheology of D″ layer." Earth and Planetary Science Letters 255, no. 3-4 (2007): 485–93. http://dx.doi.org/10.1016/j.epsl.2007.01.010.

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31

Marbouh, N., M. Belabbes, F. Khelfaoui, B. Khalfallah, A. Bentayeb, and M. Driss Khodja. "Computational study of the structural, elastic, electronic and thermoelectric properties of the orthorhombic perovskite CaIrO3 compound." Computational Condensed Matter 29 (December 2021): e00594. http://dx.doi.org/10.1016/j.cocom.2021.e00594.

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32

Kato, J., K. Hirose, H. Ozawa, and Y. Ohishi. "High-pressure experiments on phase transition boundaries between corundum, Rh2O3(II)-and CaIrO3-type structures in Al2O3." American Mineralogist 98, no. 2-3 (2013): 335–39. http://dx.doi.org/10.2138/am.2013.4133.

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33

Metsue, Arnaud, Philippe Carrez, David Mainprice, and Patrick Cordier. "Numerical modelling of dislocations and deformation mechanisms in CaIrO3 and MgGeO3 post-perovskites—Comparison with MgSiO3 post-perovskite." Physics of the Earth and Planetary Interiors 174, no. 1-4 (2009): 165–73. http://dx.doi.org/10.1016/j.pepi.2008.04.003.

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34

Mao, Z., J. F. Lin, C. Jacobs, et al. "Electronic spin and valence states of Fe in CaIrO3-type silicate post-perovskite in the Earth's lowermost mantle." Geophysical Research Letters 37, no. 22 (2010): n/a. http://dx.doi.org/10.1029/2010gl045021.

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35

Jacob, K. T., T. H. Okabe, T. Uda, and Y. Waseda. "Solid‐State Cells with Buffer Electrodes for the Measurement of Thermodynamic Properties of IrO2, CaIrO3, Ca2IrO4, and Ca4IrO6." Journal of The Electrochemical Society 146, no. 5 (1999): 1854–61. http://dx.doi.org/10.1149/1.1391855.

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36

Kurk, Sophie, Petra H. M. Peeters, Rebecca K. Stellato, et al. "Impact of skeletal muscle index (SMI) loss during palliative systemic treatment (Tx) on time to progression and overall survival (OS) in metastatic colorectal cancer (mCRC) patients." Journal of Clinical Oncology 35, no. 15_suppl (2017): 10087. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.10087.

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10087 Background: Evidence for a strong link between skeletal muscle depletion and poor outcomes in mCRC is growing. However, the impact of SMI changes over time on progression and OS during palliative systemic Tx is not known. The CAIRO3 study (Simkens et al. Lancet 2015) randomized 556 mCRC patients after 6 cycles capecitabine+oxaliplatin+bevacizumab (CAPOX-B) to maintenance CAP-B Tx (Main) vs. observation (Obs). Upon 1st disease progression (PD1), CAPOX-B or other treatment was reintroduced until 2nddisease progression (PD2). This is the first analysis using scan data of multiple time-points to investigate SMI changes during palliative systemic treatment Tx and its association with survival. Methods: 1227 CT-scans of a random selection of 416 CAIRO3 patients (mean age 64±9 years, Main n = 206; Obs n = 210) were analyzed for SMI (skeletal muscle area at the L3 level in cm2/m2). Using mixed model analysis, SMI changes were analyzed for two intervals; interval 1: from randomization to PD1, and interval 2: from PD1 to PD2. Three Cox regression models were used to study the association between SMI loss and time to PD2 and death for interval 1, and time to death for interval 2. Main and Obs groups were combined in the analyses since the p-value for interaction was not significant. Hazard ratios (HR) were reported per 2 units change in SMI. Results: Median times from randomization to PD1, PD2 and death were 7.7, 13.5 and 24 months resp. During interval 1 (less intensive or no Tx) patients gained SMI on average (1.2 units; 95%CI 0.6-1.8), but 23% of patients still lost SMI. SMI loss was associated with shorter time to PD2 (HR 0.88; 0.81-0.98, p= .01), but not with shorter OS (HR 0.94; 0.86-1.02, p= .17). During interval 2 (more intensive Tx) average SMI loss was -2.2 units ( 1.5-2.8) and 63% of patients lost SMI. SMI loss was associated with shorter OS (HR 0.73; 0.62-0.86, p< .00). Conclusions: Loss of SMI was related to shorter time to progression during first line less intensive main Tx or obs and shorter overall survival during more intensive reinduction Tx. This large longitudinal study suggests that SMI preservation may be a therapeutic goal. Clinical trial information: NCT00442637.

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Martin, C. David, Yue Meng, Vitali Prakapenka, and John B. Parise. "Gasketing optimized for large sample volume in the diamond anvil cell: first application to MgGeO3and implications for structural systematics of the perovskite to post-perovskite transition." Journal of Applied Crystallography 41, no. 1 (2008): 38–43. http://dx.doi.org/10.1107/s0021889807050029.

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Structure models of MgGeO3post-perovskite (Cmcm) are presented, along with a structure survey, demonstrating that all perovskite, post-perovskite and CaIrO3-type structures (ABX3) have specific ranges of the volume ratio between cation-centered polyhedra (VA:VB). The quality of the reported diffraction data and MgGeO3structure models is enhancedviaimplementation of a new graphite gasket for the diamond anvil cell, which stabilizes a larger sample volume, improving powder statistics during X-ray diffraction, andviathe thermal insulation required to achieve ultra-high temperatures while laser-heating samples at pressures near 100 GPa. The structure survey supports the theory that the pressure–temperature conditions under which the perovskite/post-perovskite phase transition occurs can be estimated by extrapolating the change inVA:VBto a value of 4, which corresponds to a maximum tilt ofBX6octahedra in the perovskite structure (Pbnm) where inter-octahedral anion–anion distances match the average intra-octahedral anion–anion distance. Once these short inter-octahedral distances between anions are reached in the perovskite structure, further tilting of octahedra and decrease of theVA:VBratio does not occur, driving the transition to post-perovskite structure as pressure is increased.

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Lindsay-Scott, Alex, Ian G. Wood, David P. Dobson, et al. "Thermoelastic properties and crystal structure of CaPtO3post-perovskite from 0 to 9 GPa and from 2 to 973 K." Journal of Applied Crystallography 44, no. 5 (2011): 999–1016. http://dx.doi.org/10.1107/s0021889811023582.

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ABX3post-perovskite (PPV) phases that are stable (or strongly metastable) at ambient pressure are important as analogues of PPV-MgSiO3, a deep-Earth phase stable only at very high pressure. The thermoelastic and structural properties of orthorhombic PPV-structured CaPtO3have been determined to 9.27 GPa at ambient temperature and from 2 to 973 K at ambient pressure by time-of-flight neutron powder diffraction. The equation-of-state from this high-pressure study is consistent with that found by Lindsay-Scott, Wood, Dobson, Vočadlo, Brodholt, Crichton, Hanfland & Taniguchi [(2010).Phys. Earth Planet. Inter.182, 113–118] using X-ray powder diffraction to 40 GPa. However, the neutron data have also enabled the determination of the crystal structure. Thebaxis is the most compressible and thecaxis the least, with theaandcaxes shortening under pressure by a similar amount. Above 300 K, the volumetric coefficient of thermal expansion, α(T), of CaPtO3can be represented by α(T) =a0+a1(T), witha0= 2.37 (3) × 10−5 K−1anda1= 5.1 (5) × 10−9 K−2. Over the full range of temperature investigated, the unit-cell volume of CaPtO3can be described by a second-order Grüneisen approximation to the zero-pressure equation of state, with the internal energy calculatedviaa Debye model and parameters θD(Debye temperature) = 615 (8) K,V0(unit-cell colume at 0 K) = 227.186 (3) Å3,K′0(first derivative with respect to pressure of the isothermal incompressibilityK0) = 7.9 (8) and (V0K0/γ′) = 3.16 (3) × 10−17 J, where γ′ is a Grüneisen parameter. Combining the present measurements with heat-capacity data gives a thermodynamic Grüneisen parameter γ = 1.16 (1) at 291 K. PPV-CaPtO3, PPV-MgSiO3and PPV-CaIrO3have the same axial incompressibility sequence, κc > κa > κb. However, when heated, CaPtO3shows axial expansion in the form αc > αb > αa, a sequence which is not simply the inverse of the axial incompressibilities. In this respect, CaPtO3differs from both MgSiO3(where the sequence αb > αa > αcis the same as 1/κi) and CaIrO3(where αb > αc > αa). Thus, PPV-CaPtO3and PPV-CaIrO3are better analogues for PPV-MgSiO3in compression than on heating. The behaviour of the unit-cell axes of all three compounds was analysed using a model based on nearest-neighbourB—XandA—Xdistances and angles specifying the geometry and orientation of theBX6octahedra. Under pressure, all contract mainly by reduction in theB—XandA—Xdistances. On heating, MgSiO3expands (at high pressure) mainly by lengthening of the Si—O and Mg—O bonds. In contrast, the expansion of CaPtO3(and possibly also CaIrO3), at atmospheric pressure, arises more from changes in angles than from increased bond distances.

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39

Miyajima, Nobuyoshi, and Nicolas Walte. "Burgers vector determination in deformed perovskite and post-perovskite of CaIrO3 using thickness fringes in weak-beam dark-field images." Ultramicroscopy 109, no. 6 (2009): 683–92. http://dx.doi.org/10.1016/j.ultramic.2009.01.010.

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40

Avdeev, Maxim, El'ad N. Caspi, and Sergey Yakovlev. "On the polyhedral volume ratios VA /VB in perovskites ABX 3." Acta Crystallographica Section B Structural Science 63, no. 3 (2007): 363–72. http://dx.doi.org/10.1107/s0108768107001140.

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This paper presents analytical expressions for the calculation of ratios of cation coordination polyhedra volumes (VA /VB ) for perovskites ABX 3 of the Stokes–Howard diagram directly from atomic coordinates. We show the advantages of quantifying perovskite structure distortion with polyhedral volume ratios rather than with tilting angles, and discuss why space groups with multiple crystallographically inequivalent A or B sites (I4/mmm, Immm, P42/nmc etc.) are much less common than those with a single A and B site (I4/mcm, R\bar 3c, Pnma etc.). Analysis of crystallographic data for approximately 1300 perovskite structures of oxides, halides and chalcogenides from the Inorganic Crystal Structure Database revealed that the most highly distorted perovskites belong to the space group Pnma and formally lower-symmetry perovskites (I2/m, I2/a) are less distorted geometrically. Critical values of the VA /VB ratios for the most common phase transitions Pnma ↔ I4/mcm and Pnma↔ R\bar 3c are estimated to be ∼ 4.85 with the possible intermediate space group Imma stable in the very narrow range of VA /VB ≃ 4.8–4.9. Transitions to post-perovskite CaIrO3-type structures may be expected for VA /VB < 3.8.

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Stølen, Svein, and Reidar G. Trønnes. "The perovskite to post-perovskite transition in CaIrO3: Clapeyron slope and changes in bulk and shear moduli by density functional theory." Physics of the Earth and Planetary Interiors 164, no. 1-2 (2007): 50–62. http://dx.doi.org/10.1016/j.pepi.2007.05.009.

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Kurk, Sophie A., Petra H. M. Peeters, Bram Dorresteijn, et al. "Loss of skeletal muscle index and survival in patients with metastatic colorectal cancer: Secondary analysis of the phase 3 CAIRO3 trial." Cancer Medicine 9, no. 3 (2019): 1033–43. http://dx.doi.org/10.1002/cam4.2787.

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Nakatsuka, Akihiko, Kazumasa Sugiyama, Akira Yoneda, Keiko Fujiwara, and Akira Yoshiasa. "Crystal structure of post-perovskite-type CaIrO3reinvestigated: new insights into atomic thermal vibration behaviors." Acta Crystallographica Section E Crystallographic Communications 71, no. 9 (2015): 1109–13. http://dx.doi.org/10.1107/s2056989015015649.

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Single crystals of the title compound, the post-perovskite-type CaIrO3[calcium iridium(IV) trioxide], have been grown from a CaCl2flux at atmospheric pressure. The crystal structure consists of an alternate stacking of IrO6octahedral layers and CaO8hendecahedral layers along [010]. Chains formed by edge-sharing of IrO6octahedra (point-group symmetry 2/m..) run along [100] and are interconnected along [001] by sharing apical O atoms to build up the IrO6octahedral layers. Chains formed by face-sharing of CaO8hendecahedra (point-group symmetrym2m) run along [100] and are interconnected along [001] by edge-sharing to build up the CaO8hendecahedral layers. The IrO6octahedral layers and CaO8hendecahedral layers are interconnected by sharing edges. The present structure refinement using a high-power X-ray source confirms the atomic positions determined by Hiraiet al.(2009) [Z. Kristallogr.224, 345–350], who had revised our previous report [Sugaharaet al.(2008).Am. Mineral.93, 1148–1152]. However, the displacement ellipsoids of the Ir and Ca atoms based on the present refinement can be approximated as uniaxial ellipsoids elongating along [100], unlike those reported by Hiraiet al.(2009). This suggests that the thermal vibrations of the Ir and Ca atoms are mutually suppressed towards the Ir...Ca direction across the shared edge because of the dominant repulsion between the two atoms.

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Martin, C. D., R. I. Smith, W. G. Marshall, and J. B. Parise. "High-pressure structure and bonding in CaIrO3: The structure model of MgSiO3 post-perovskite investigated with time-of-flight neutron powder diffraction." American Mineralogist 92, no. 11-12 (2007): 1912–18. http://dx.doi.org/10.2138/am.2007.2585.

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Simkens, Lieke H. J., Harm van Tinteren, Anne May, et al. "Maintenance treatment with capecitabine and bevacizumab in metastatic colorectal cancer (CAIRO3): a phase 3 randomised controlled trial of the Dutch Colorectal Cancer Group." Lancet 385, no. 9980 (2015): 1843–52. http://dx.doi.org/10.1016/s0140-6736(14)62004-3.

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Goey, K. K. H., S. G. Elias, H. van Tinteren, et al. "Maintenance treatment with capecitabine and bevacizumab versus observation in metastatic colorectal cancer: updated results and molecular subgroup analyses of the phase 3 CAIRO3 study." Annals of Oncology 28, no. 9 (2017): 2128–34. http://dx.doi.org/10.1093/annonc/mdx322.

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Kurk, S. A., P. H. M. Peeters, B. Dorresteijn, et al. "Evolution of skeletal muscle mass (SMM) during palliative systemic treatment in metastatic colorectal cancer (mCRC) patients participating in the randomized phase 3 CAIRO3 study." Annals of Oncology 27 (October 2016): vi199. http://dx.doi.org/10.1093/annonc/mdw370.142.

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48

MESTYAN, ADAM. "Power and music in Cairo: Azbakiyya." Urban History 40, no. 4 (2013): 681–704. http://dx.doi.org/10.1017/s0963926813000229.

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ABSTRACTIn this article, the origins of the modern metropolis are reconsidered, using the example of Cairo within its Ottoman and global context. I argue that Cairo's Azbakiyya Garden served as a central ground for fashioning a dynastic capital throughout the nineteenth century. This argument sheds new light on the politics of Khedive Ismail, who introduced a new state representation through urban planning and music theatre. The social history of music in Azbakiyya proves that, instead of functioning as an example of colonial division, Cairo encompassed competing conceptions of class, taste and power.

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van Dijk, Erik, Hedde D. Biesma, Martijn Cordes, et al. "Loss of Chromosome 18q11.2-q12.1 Is Predictive for Survival in Patients With Metastatic Colorectal Cancer Treated With Bevacizumab." Journal of Clinical Oncology 36, no. 20 (2018): 2052–60. http://dx.doi.org/10.1200/jco.2017.77.1782.

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Purpose Patients with metastatic colorectal cancer (mCRC) have limited benefit from the addition of bevacizumab to standard chemotherapy. However, a subset probably benefits substantially, highlighting an unmet clinical need for a biomarker of response to bevacizumab. Previously, we demonstrated that losses of chromosomes 5q34, 17q12, and 18q11.2-q12.1 had a significant correlation with progression-free survival (PFS) in patients with mCRC treated with bevacizumab in the CAIRO2 clinical trial but not in patients who did not receive bevacizumab in the CAIRO trial. This study was designed to validate these findings. Materials and Methods Primary mCRC samples were analyzed from two cohorts of patients who received bevacizumab as first-line treatment; 96 samples from the European multicenter study Angiopredict (APD) and 81 samples from the Italian multicenter study, MOMA. A third cohort of 90 samples from patients with mCRC who did not receive bevacizumab was analyzed. Copy number aberrations of tumor biopsy specimens were measured by shallow whole-genome sequencing and were correlated with PFS, overall survival (OS), and response. Results Loss of chromosome 18q11.2-q12.1 was associated with prolonged PFS most significantly in both the cohorts that received bevacizumab (APD: hazard ratio, 0.54; P = .01; PFS difference, 65 days; MOMA: hazard ratio, 0.55; P = .019; PFS difference, 49 days). A similar association was found for OS and overall response rate in these two cohorts, which became significant when combined with the CAIRO2 cohort. Median PFS in the cohort of patients with mCRC who did not receive bevacizumab and in the CAIRO cohort was similar to that of the APD, MOMA, and CAIRO2 patients without an 18q11.2-q12.1 loss. Conclusion We conclude that the loss of chromosome 18q11.2-q12.1 is consistently predictive for prolonged PFS in patients receiving bevacizumab. The predictive value of this loss is substantiated by a significant gain in OS and overall response rate.

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Dubrovinsky, Leonid. "Polymorphism and electronic transformations of deep Earth minerals." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C37. http://dx.doi.org/10.1107/s2053273314099628.

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While powder X-ray diffraction studies stepped over a megabar in pressure already in the 1970s, single crystal experiments remained much rarer and covered until recently a very limited pressure range barely reaching 15 GPa. Recent technological advances resulted in a revolutionary breakthrough in the high-pressure crystallography. The structure solution and the full refinement are now possible at pressures over 100 GPa. A comprehensive understanding of the iron- and aluminum-bearing magnesium silicate perovskite (Pv) and post-perovskite (PPv, CaIrO3-type) crystal structures and their evolution under pressure and temperature is vital for evaluating seismic data of the Earth's lower mantle. We investigated materials with different compositions and iron oxidation states by means of single-crystal X-ray diffraction at pressures over 150 GPa and temperatures over 2500 K, and by Mössbauer spectroscopy. By structural studies of Pv at extreme conditions, we found (a) no spin state crossover in ferric iron occupying the bicapped trigonal prism ("A" crystallographic site), and (b) no crystal-chemically significant amount of ferric iron in the octahedral "B-site at any conditions of our experiments. We synthesized single crystals of PPv, refined their structure and distribution of iron between the structural sites. We demonstrated that incorporation of ferric iron and aluminum significantly increases the compressibility of magnesium silicate Pv and PPv. Based on experimental data we constrained the thermal equation of state for Pv and PPv with a variable content of iron (ferrous and ferric) and aluminum. We concluded that variation of Fe3+/ΣFe can lead to significant changes of Pv bulk sound velocity (over 1%) demonstrating that the oxidation state of iron is a critical parameter for interpretation of seismic tomography data.

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