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https://www.readbyqxmd.com/read/28345655/large-electrocaloric-effect-in-relaxor-ferroelectric-and-antiferroelectric-lanthanum-doped-lead-zirconate-titanate-ceramics
#1
Biao Lu, Peilian Li, Zhenhua Tang, Yingbang Yao, Xingsen Gao, Wolfgang Kleemann, Sheng-Guo Lu
Both relaxor ferroelectric and antiferroelectric materials can individually demonstrate large electrocaloric effects (ECE). However, in order to further enhance the ECE it is crucial to find a material system, which can exhibit simultaneously both relaxor ferroelectric and antiferroelectric properties, or easily convert from one into another in terms of the compositional tailoring. Here we report on a system, in which the structure can readily change from antiferroelectric into relaxor ferroelectric and vice versa...
March 27, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28345044/continental-igneous-rock-composition-a-major-control-of-past-global-chemical-weathering
#2
Clément P Bataille, Amy Willis, Xiao Yang, Xiao-Ming Liu
The composition of igneous rocks in the continental crust has changed throughout Earth's history. However, the impact of these compositional variations on chemical weathering, and by extension on seawater and atmosphere evolution, is largely unknown. We use the strontium isotope ratio in seawater [((87)Sr/(86)Sr)seawater] as a proxy for chemical weathering, and we test the sensitivity of ((87)Sr/(86)Sr)seawater variations to the strontium isotopic composition ((87)Sr/(86)Sr) in igneous rocks generated through time...
March 2017: Science Advances
https://www.readbyqxmd.com/read/28338853/radiological-impacts-assessment-for-workers-in-ceramic-industry-in-serbia
#3
Nataša Todorovic, Dušan Mrda, Jan Hansman, Slavko Todorovic, Jovana Nikolov, Miodrag Krmar
Studies have been carried out to determine the natural radioactivity in some materials used in ceramic industry (zircon, zirkosil, Zircobit MO/S, zircon silicate, zirklonil frit, hematite, bentonite, wollastonite, raw kaolin, kaolinized granite, sileks ball, feldspar, pigment, white base serigraphic, engobe) and their associated radiation hazard. The external hazard index, Hex, values, radium equivalent activity, Raeq, total absorbed dose rates, D and annual effective dose, De were derived for all measured materials and compared with the recommended values to assess the external radiation hazards to workers who worked in ceramic industries in Serbia...
March 3, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28333626/temperature-dependence-of-domain-contributions-as-a-function-of-ageing-in-soft-and-hard-lead-zirconate-titanate-piezoelectric-ceramics
#4
Sayyed A Qaisar, Timothy P Comyn, Andrew J Bell
The stress and temperature dependence of three different PZT ceramics have been measured at 48 hours and 1 month after poling. The data were fitted to a modified Rayleigh law in which a negative quadratic stress term accounts for a saturation of the domain wall contributions at higher stress. The relative changes to the fitting parameters can be explained by the materials possessing differences in the concentration of orientable defect dipoles, but with similar distributions of relaxation time constants.
March 22, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28325934/cordillera-zealandia-a-mesozoic-arc-flare-up-on-the-palaeo-pacific-gondwana-margin
#5
L A Milan, N R Daczko, G L Clarke
Two geochemically and temporally distinct components of the Mesozoic Zealandia Cordilleran arc indicate a shift from low to high Sr/Y whole rock ratios at c. 130 Ma. Recent mapping and a reappraisal of published Sr-Nd data combined with new in-situ zircon Hf isotope analyses supports a genetic relationship between the two arc components. A reappraisal of geophysical, geochemical and P-T estimates demonstrates a doubling in thickness of the arc to at least 80 km at c. 130 Ma. Contemporaneously, magmatic addition rates shifted from ~14 km(3)/my per km of arc to a flare-up involving ~100 km(3)/my per km of arc...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28325908/tuning-of-large-piezoelectric-response-in-nanosheet-buffered-lead-zirconate-titanate-films-on-glass-substrates
#6
Anuj Chopra, Muharrem Bayraktar, Maarten Nijland, Johan E Ten Elshof, Fred Bijkerk, Guus Rijnders
Renewed interest has been witnessed in utilizing the piezoelectric response of PbZr0.52Ti0.48O3 (PZT) films on glass substrates for applications such as adaptive optics. Accordingly, new methodologies are being explored to grow well-oriented PZT thin films to harvest a large piezoelectric response. However, thin film piezoelectric response is significantly reduced compared to intrinsic response due to substrate induced clamping, even when films are well-oriented. Here, a novel method is presented to grow preferentially (100)-oriented PZT films on glass substrates by utilizing crystalline nanosheets as seed layers...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28282968/temporal-and-structural-evolution-of-the-early-pal%C3%A3-ogene-rocks-of-the-seychelles-microcontinent
#7
J Gregory Shellnutt, Meng-Wan Yeh, Kenshi Suga, Tung-Yi Lee, Hao-Yang Lee, Te-Hsien Lin
The Early Palæogene Silhouette/North Island volcano-plutonic complex was emplaced during the rifting of the Seychelles microcontinent from western India. The complex is thought to have been emplaced during magnetochron C28n. However, the magnetic polarities of the rocks are almost entirely reversed and inconsistent with a normal polarity. In this study we present new in situ zircon U/Pb geochronology of the different intrusive facies of the Silhouette/North Island complex in order to address the timing of emplacement and the apparent magnetic polarity dichotomy...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28273880/5-v-compatible-two-axis-pzt-driven-mems-scanning-mirror-with-mechanical-leverage-structure-for-miniature-lidar-application
#8
Liangchen Ye, Gaofei Zhang, Zheng You
The MEMS (Micro-Electronical Mechanical System) scanning mirror is an optical MEMS device that can scan laser beams across one or two dimensions. MEMS scanning mirrors can be applied in a variety of applications, such as laser display, bio-medical imaging and Light Detection and Ranging (LiDAR). These commercial applications have recently created a great demand for low-driving-voltage and low-power MEMS mirrors. However, no reported two-axis MEMS scanning mirror is available for usage in a universal supplying voltage such as 5 V...
March 5, 2017: Sensors
https://www.readbyqxmd.com/read/28257006/solid-state-nmr-and-short-range-order-in-crystalline-oxides-and-silicates-a-new-tool-in-paramagnetic-resonances
#9
Jonathan F Stebbins, Ryan J McCarty, Aaron C Palke
Most applications of high-resolution NMR to questions of short-range order/disorder in inorganic materials have been made in systems where ions with unpaired electron spins are of negligible concentration, with structural information extracted primarily from chemical shifts, quadrupolar coupling parameters, and nuclear dipolar couplings. In some cases, however, the often-large additional resonance shifts caused by interactions between unpaired electron and nuclear spins can provide unique new structural information in materials with contents of paramagnetic cations ranging from hundreds of ppm to several per cent and even higher...
March 1, 2017: Acta Crystallographica. Section C, Structural Chemistry
https://www.readbyqxmd.com/read/28247756/strongly-enhanced-piezoelectric-response-in-lead-zirconate-titanate-films-with-vertically-aligned-columnar-grains
#10
Minh D Nguyen, Evert P Houwman, Matthijn Dekkers, Guus Rijnders
Pb(Zr0.52Ti0.48)O3 (PZT) films with (001) orientation were deposited on Pt(111)/Ti/SiO2/Si(100) substrates using pulsed laser deposition. Variation of the laser pulse rate during the deposition of the PZT films was found to play a key role in the control of the microstructure and to change strongly the piezoelectric response of the thin film. The film deposited at low pulse rate has a denser columnar microstructure, which improves the transverse piezoelectric coefficient (d31f) and ferroelectric remanent polarization (Pr), whereas the less densely packed columnar grains in the film deposited at high pulse rates give rise to a significantly higher longitudinal piezoelectric coefficient (d33f) value...
March 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28246632/seeing-is-believing-visualization-of-he-distribution-in-zircon-and-implications-for-thermal-history-reconstruction-on-single-crystals
#11
Martin Danišík, Brent I A McInnes, Christopher L Kirkland, Brad J McDonald, Noreen J Evans, Thomas Becker
Zircon (U-Th)/He thermochronometry is an established radiometric dating technique used to place temporal constraints on a range of thermally sensitive geological events, such as crustal exhumation, volcanism, meteorite impact, and ore genesis. Isotopic, crystallographic, and/or mineralogical heterogeneities within analyzed grains can result in dispersed or anomalous (U-Th)/He ages. Understanding the effect of these grain-scale phenomena on the distribution of He in analyzed minerals should lead to improvements in data interpretation...
February 2017: Science Advances
https://www.readbyqxmd.com/read/28241503/measurement-of-the-length-of-installed-rock-bolt-based-on-stress-wave-reflection-by-using-a-giant-magnetostrictive-gms-actuator-and-a-pzt-sensor
#12
Mingzhang Luo, Weijie Li, Bo Wang, Qingqing Fu, Gangbing Song
Rock bolts, as a type of reinforcing element, are widely adopted in underground excavations and civil engineering structures. Given the importance of rock bolts, the research outlined in this paper attempts to develop a portable non-destructive evaluation method for assessing the length of installed rock bolts for inspection purposes. Traditionally, piezoelectric elements or hammer impacts were used to perform non-destructive evaluation of rock bolts. However, such methods suffered from many major issues, such as the weak energy generated and the requirement for permanent installation for piezoelectric elements, and the inconsistency of wave generation for hammer impact...
February 23, 2017: Sensors
https://www.readbyqxmd.com/read/28230080/demonstrating-the-potential-of-yttrium-doped-barium-zirconate-electrolyte-for-high-performance-fuel-cells
#13
Kiho Bae, Dong Young Jang, Hyung Jong Choi, Donghwan Kim, Jongsup Hong, Byung-Kook Kim, Jong-Ho Lee, Ji-Won Son, Joon Hyung Shim
In reducing the high operating temperatures (≥800 °C) of solid-oxide fuel cells, use of protonic ceramics as an alternative electrolyte material is attractive due to their high conductivity and low activation energy in a low-temperature regime (≤600 °C). Among many protonic ceramics, yttrium-doped barium zirconate has attracted attention due to its excellent chemical stability, which is the main issue in protonic-ceramic fuel cells. However, poor sinterability of yttrium-doped barium zirconate discourages its fabrication as a thin-film electrolyte and integration on porous anode supports, both of which are essential to achieve high performance...
February 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28140395/archaean-zircons-in-miocene-oceanic-hotspot-rocks-establish-ancient-continental-crust-beneath-mauritius
#14
Lewis D Ashwal, Michael Wiedenbeck, Trond H Torsvik
A fragment of continental crust has been postulated to underlie the young plume-related lavas of the Indian Ocean island of Mauritius based on the recovery of Proterozoic zircons from basaltic beach sands. Here we document the first U-Pb zircon ages recovered directly from 5.7 Ma Mauritian trachytic rocks. We identified concordant Archaean xenocrystic zircons ranging in age between 2.5 and 3.0 Ga within a trachyte plug that crosscuts Older Series plume-related basalts of Mauritius. Our results demonstrate the existence of ancient continental crust beneath Mauritius; based on the entire spectrum of U-Pb ages for old Mauritian zircons, we demonstrate that this ancient crust is of central-east Madagascar affinity, which is presently located ∼700 km west of Mauritius...
January 31, 2017: Nature Communications
https://www.readbyqxmd.com/read/28134296/critical-scattering-and-incommensurate-phase-transition-in-antiferroelectric-pbzro3-under-pressure
#15
R G Burkovsky, I Bronwald, D Andronikova, B Wehinger, M Krisch, J Jacobs, D Gambetti, K Roleder, A Majchrowski, A V Filimonov, A I Rudskoy, S B Vakhrushev, A K Tagantsev
Antiferroelectric lead zirconate is the key ingredient in modern ferroelectric and piezoelectric functional solid solutions. By itself it offers opportunities in new-type non-volatile memory and energy storage applications. A highly useful and scientifically puzzling feature of this material is the competition between the ferro- and antiferroelectric phases due to their energetic proximity, which leads to a challenge in understanding of the critical phenomena driving the formation of the antiferroelectric structure...
January 30, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28134066/laser-assisted-atom-probe-tomography-of-deformed-minerals-a-zircon-case-study
#16
Alexandre La Fontaine, Sandra Piazolo, Patrick Trimby, Limei Yang, Julie M Cairney
The application of atom probe tomography to the study of minerals is a rapidly growing area. Picosecond-pulsed, ultraviolet laser (UV-355 nm) assisted atom probe tomography has been used to analyze trace element mobility within dislocations and low-angle boundaries in plastically deformed specimens of the nonconductive mineral zircon (ZrSiO4), a key material to date the earth's geological events. Here we discuss important experimental aspects inherent in the atom probe tomography investigation of this important mineral, providing insights into the challenges in atom probe tomography characterization of minerals as a whole...
January 30, 2017: Microscopy and Microanalysis
https://www.readbyqxmd.com/read/28120860/magma-reservoir-dynamics-at-toba-caldera-indonesia-recorded-by-oxygen-isotope-zoning-in-quartz
#17
David A Budd, Valentin R Troll, Frances M Deegan, Ester M Jolis, Victoria C Smith, Martin J Whitehouse, Chris Harris, Carmela Freda, David R Hilton, Sæmundur A Halldórsson, Ilya N Bindeman
Quartz is a common phase in high-silica igneous rocks and is resistant to post-eruptive alteration, thus offering a reliable record of magmatic processes in silicic magma systems. Here we employ the 75 ka Toba super-eruption as a case study to show that quartz can resolve late-stage temporal changes in magmatic δ(18)O values. Overall, Toba quartz crystals exhibit comparatively high δ(18)O values, up to 10.2‰, due to magma residence within, and assimilation of, local granite basement. However, some 40% of the analysed quartz crystals display a decrease in δ(18)O values in outermost growth zones compared to their cores, with values as low as 6...
January 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28117834/refined-ordovician-timescale-reveals-no-link-between-asteroid-breakup-and-biodiversification
#18
A Lindskog, M M Costa, C M Ø Rasmussen, J N Connelly, M E Eriksson
The catastrophic disruption of the L chondrite parent body in the asteroid belt c. 470 Ma initiated a prolonged meteorite bombardment of Earth that started in the Ordovician and continues today. Abundant L chondrite meteorites in Middle Ordovician strata have been interpreted to be the consequence of the asteroid breakup event. Here we report a zircon U-Pb date of 467.50±0.28 Ma from a distinct bed within the meteorite-bearing interval of southern Sweden that, combined with published cosmic-ray exposure ages of co-occurring meteoritic material, provides a precise age for the L chondrite breakup at 468...
January 24, 2017: Nature Communications
https://www.readbyqxmd.com/read/28106012/high-pressure-structural-elastic-and-thermodynamic-properties-of-zircon-type-hopo4-and-tmpo4
#19
O Gomis, B Lavina, P Rodríguez-Hernández, A Muñoz, R Errandonea, D Errandonea, M Bettinelli
Zircon-type holmium phosphate (HoPO4) and thulium phosphate (TmPO4) have been studied by single-crystal x-ray diffraction and ab initio calculations. We report on the influence of pressure on the crystal structure, and on the elastic and thermodynamic properties. The equation of state for both compounds is accurately determined. We have also obtained information on the polyhedral compressibility which is used to explain the anisotropic axial compressibility and the bulk compressibility. Both compounds are ductile and more resistive to volume compression than to shear deformation at all pressures...
March 8, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28103275/a-theoretical-model-for-predicting-residual-stress-generation-in-fabrication-process-of-double-ceramic-layer-thermal-barrier-coating-system
#20
Yan Song, Weijie Wu, Feng Xie, Yilun Liu, Tiejun Wang
Residual stress arisen in fabrication process of Double-Ceramic-Layer Thermal Barrier Coating System (DCL-TBCs) has a significant effect on its quality and reliability. In this work, based on the practical fabrication process of DCL-TBCs and the force and moment equilibrium, a theoretical model was proposed at first to predict residual stress generation in its fabrication process, in which the temperature dependent material properties of DCL-TBCs were incorporated. Then, a Finite Element method (FEM) has been carried out to verify our theoretical model...
2017: PloS One
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