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Full-Text Articles in Physical Sciences and Mathematics
The Progenitors Of The Compact Early-Type Galaxies At High Redshift, Christina C. Williams, Mauro Giavalisco, Paolo Cassata, Elena Tundo, Tommy Wiklind, Yicheng Guo, Bomee Lee, Guillermo Barro, Stijn Wuyts, Eric F. Bell, Christopher J. Conselice, Avishai Dekel, Sandra M. Faber, Henry C. Ferguson, Norman A. Grogin, Nimish Hathi, Kuang-Han Huang, Dalibor D. Kocevski, Anton M. Koekemoer, David C. Koo, Swara Ravindranath, Sarah Salimbeni
The Progenitors Of The Compact Early-Type Galaxies At High Redshift, Christina C. Williams, Mauro Giavalisco, Paolo Cassata, Elena Tundo, Tommy Wiklind, Yicheng Guo, Bomee Lee, Guillermo Barro, Stijn Wuyts, Eric F. Bell, Christopher J. Conselice, Avishai Dekel, Sandra M. Faber, Henry C. Ferguson, Norman A. Grogin, Nimish Hathi, Kuang-Han Huang, Dalibor D. Kocevski, Anton M. Koekemoer, David C. Koo, Swara Ravindranath, Sarah Salimbeni
Physics and Astronomy Faculty Publications
We use GOODS and CANDELS images to identify progenitors of massive (M > 1010 M ☉) compact early-type galaxies (ETGs) at z ~ 1.6. Because merging and accretion increase the size of the stellar component of galaxies, if the progenitors are among known star-forming galaxies, these must be compact themselves. We select candidate progenitors among compact Lyman-break galaxies at z ~ 3 on the basis of their mass, star-formation rate (SFR), and central stellar density, and we find that these account for a large fraction of, and possibly all, compact ETGs at z ~ 1.6. We find that …
The Properties Of Post-Starburst Quasars Based On Optical Spectroscopy, Sabrina L. Cales, Michael S. Brotherton, Zhaohui Shang, Jessie C. Runnoe, Michael A. Dipompeo, Vardha Nicola Bennert, Gabriela Canalizo, Kyle D. Hiner, R. Stoll, Rajib Ganguly, Aleksandar Diamond-Stanic
The Properties Of Post-Starburst Quasars Based On Optical Spectroscopy, Sabrina L. Cales, Michael S. Brotherton, Zhaohui Shang, Jessie C. Runnoe, Michael A. Dipompeo, Vardha Nicola Bennert, Gabriela Canalizo, Kyle D. Hiner, R. Stoll, Rajib Ganguly, Aleksandar Diamond-Stanic
Physics
We present optical spectroscopy of a sample of 38 post-starburst quasars (PSQs) at z ~ 0.3, 29 of which have morphological classifications based on Hubble Space Telescope imaging. These broad-lined active galactic nuclei (AGNs) possess the spectral signatures of massive intermediate-aged stellar populations, making them potentially useful for studying connections between nuclear activity and host galaxy evolution. We model the spectra in order to determine the ages and masses of the host stellar populations, and the black hole masses and Eddington fractions of the AGNs. Our model components include an instantaneous starburst, a power law, and emission lines. We find …
Microbially Induced Sedimentary Structures Recording An Ancient Ecosystem In The Ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia, Nora Noffke, Daniel Christian, David Wacey, Robert M. Hazen
Microbially Induced Sedimentary Structures Recording An Ancient Ecosystem In The Ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia, Nora Noffke, Daniel Christian, David Wacey, Robert M. Hazen
OES Faculty Publications
Microbially induced sedimentary structures (MISS) result from the response of microbial mats to physical sediment dynamics. MISS are cosmopolitan and found in many modern environments, including shelves, tidal flats, lagoons, riverine shores, lakes, interdune areas, and sabkhas. The structures record highly diverse communities of microbial mats and have been reported from numerous intervals in the geological record up to 3.2 billion years (Ga) old. This contribution describes a suite of MISS from some of the oldest well-preserved sedimentary rocks in the geological record, the early Archean (ca. 3.48 Ga) Dresser Formation, Western Australia. Outcrop mapping at the meter to …
Microstructural Origin For The Piezoelectricity Evolution In (K0.5na0.5)Nbo3-Based Lead-Free Ceramics, Hanzheng Guo, Shujun Zhang, Scott P. Beckman, Xiaoli Tan
Microstructural Origin For The Piezoelectricity Evolution In (K0.5na0.5)Nbo3-Based Lead-Free Ceramics, Hanzheng Guo, Shujun Zhang, Scott P. Beckman, Xiaoli Tan
Australian Institute for Innovative Materials - Papers
Chemically modified (K0.5Na0.5)NbO3 compositions with finely tuned polymorphic phase boundaries (PPBs) have shown excellent piezoelectric properties. The evolution of the domain morphology and crystal structure under applied electric fields of a model material, 0.948(K0.5Na0.5)NbO3-0.052LiSbO3, was directly visualized using in situ transmission electron microscopy. The in situ observations correlate extremely well with measurements of the electromechanical response on bulk samples. It is found that the origin of the excellent piezoelectric performance in this lead-free composition is due to a tilted monoclinic phase that emerges from the PPB when poling fields greater than 14 kV/cm are applied. 2013 AIP Publishing LLC.
Aging Effect Evolution During Ferroelectric-Ferroelectric Phase Transition: A Mechanism Study, Zuyong Feng, Zhenxiang Cheng, Dongqi Shi, S X. Dou
Aging Effect Evolution During Ferroelectric-Ferroelectric Phase Transition: A Mechanism Study, Zuyong Feng, Zhenxiang Cheng, Dongqi Shi, S X. Dou
Australian Institute for Innovative Materials - Papers
Aging can significantly modify the dielectric, piezoelectric, and ferroelectric performance of ferroelectrics. However, little attention has been paid to the aging effect during ferroelectric-ferroelectric phase transitions that is essentially correlated with real applications. In this letter, the authors report the aging effect evolution between two ferroelectric phases in an acceptor-doped piezoceramics. The results show that aging-induced double hysteresis loops were exhibited in different ferroelectric phases, but disappeared during ferroelectric-ferroelectric phase transitions, suggesting the mechanism that the intrinsic restoring force for the reversible switching of domains caused by the alignment of defect dipoles was weakened due to ferroelectric dipole reorientation.
Crystallization, Phase Evolution And Ferroelectric Properties Of Sol-Gel-Synthesized Ba(Ti0.8zr0.2)O3- X(Ba0.7ca0.3)Tio3 Thin Films, Zeng-Mei Wang, Kuan Zhao, Xin-Li Guo, Wei Sun, Hua-Long Jiang, Xue-Qin Han, Xu-Tang Tao, Zhen-Xiang Cheng, Hong-Yang Zhao, Hideo Kimura, Guo-Liang Yuan, Jiang Yin, Zhi-Guo Liu
Crystallization, Phase Evolution And Ferroelectric Properties Of Sol-Gel-Synthesized Ba(Ti0.8zr0.2)O3- X(Ba0.7ca0.3)Tio3 Thin Films, Zeng-Mei Wang, Kuan Zhao, Xin-Li Guo, Wei Sun, Hua-Long Jiang, Xue-Qin Han, Xu-Tang Tao, Zhen-Xiang Cheng, Hong-Yang Zhao, Hideo Kimura, Guo-Liang Yuan, Jiang Yin, Zhi-Guo Liu
Australian Institute for Innovative Materials - Papers
A lead-free piezoelectric material with ultra-high properties, Ba(Ti0.8Zr0.2)O3-x(Ba0.7Ca0.3)TiO3(BZT-xBCT) nanocrystals was synthesized via a sol-gel method, and the corresponding thin films were also deposited on Pt/Ti/SiO2/Si substrates by a spin-coating approach. The BZT-xBCT thin film exhibited a high remnant polarization of 22.15 mC cm2 with a large coercive field of 68.06 kV cm1. The resultant gel is calcined at various elevated temperatures and studied with FTIR/XRD/Raman/DSC-TGA/AFM/SEM techniques for gel composition, crystallization, phase transition, thermochemistry and the morphology of the film. Although the room temperature crystal structure of the BZT-xBCT nanocrystals appears to be a standard perovskite structure by conventional X-ray diffraction …