Institution
Oak Ridge National Laboratory
Facility•Oak Ridge, Tennessee, United States•
About: Oak Ridge National Laboratory is a facility organization based out in Oak Ridge, Tennessee, United States. It is known for research contribution in the topics: Neutron & Ion. The organization has 31868 authors who have published 73724 publications receiving 2633689 citations. The organization is also known as: ORNL.
Topics: Neutron, Ion, Scattering, Neutron scattering, Microstructure
Papers published on a yearly basis
Papers
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TL;DR: In this paper, the authors reported the observation of local modes in La-filled skutterdite antimonides, using heat capacity, elastic constant and inelastic neutron scattering measurements.
Abstract: Filled skutterudite antimonides1,2 are cubic compounds with the formula RM4Sb12, where R is a rare-earth element (such as La or Ce), and M is a transition metal (for example, Fe or Co). The rare-earth ion is weakly bound in an oversized atomic cage formed by the other atoms. Its presence has been shown to cause a dramatic reduction in the lattice component of the thermal conductivity, while having little effect on the electronic properties3,4,5 of the compound. This combination of properties makes filled skutterudites of interest as thermoelectric materials. It has been suggested4 that localized, incoherent vibrations of the rare-earth ion are responsible for the reduction in thermal conductivity, but no direct evidence for these local vibrational modes exists. Here we report the observation of local modes in La-filled skutterudites, using heat capacity, elastic constant and inelastic neutron scattering measurements. The La atoms show unusual thermodynamic behaviour, characterized by the presence of two low-energy localized modes. Our results suggest that consideration of local modes will play an important role in the design of the next generation of thermoelectric materials.
473 citations
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TL;DR: This paper used a non-targeted, shotgun mass spectrometry-based whole community proteomics approach for the first deep proteome measurements of thousands of proteins in human fecal samples, thus demonstrating this approach on the most complex sample type to date.
Abstract: The human gut contains a dense, complex and diverse microbial community, comprising the gut microbiome. Metagenomics has recently revealed the composition of genes in the gut microbiome, but provides no direct information about which genes are expressed or functioning. Therefore, our goal was to develop a novel approach to directly identify microbial proteins in fecal samples to gain information about the genes expressed and about key microbial functions in the human gut. We used a non-targeted, shotgun mass spectrometry-based whole community proteomics, or metaproteomics, approach for the first deep proteome measurements of thousands of proteins in human fecal samples, thus demonstrating this approach on the most complex sample type to date. The resulting metaproteomes had a skewed distribution relative to the metagenome, with more proteins for translation, energy production and carbohydrate metabolism when compared to what was earlier predicted from metagenomics. Human proteins, including antimicrobial peptides, were also identified, providing a non-targeted glimpse of the host response to the microbiota. Several unknown proteins represented previously undescribed microbial pathways or host immune responses, revealing a novel complex interplay between the human host and its associated microbes.
472 citations
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TL;DR: Field-effect transistors made from the few-layer PdSe2 display tunable ambipolar charge carrier conduction with a high electron field-effect mobility of ∼158 cm2 V-1 s-1, indicating the promise of this anisotropic, air-stable, pentagonal 2D material for 2D electronics.
Abstract: Most studied two-dimensional (2D) materials exhibit isotropic behavior due to high lattice symmetry; however, lower-symmetry 2D materials such as phosphorene and other elemental 2D materials exhibit very interesting anisotropic properties. In this work, we report the atomic structure, electronic properties, and vibrational modes of few-layered PdSe2 exfoliated from bulk crystals, a pentagonal 2D layered noble transition metal dichalcogenide with a puckered morphology that is air-stable. Micro-absorption optical spectroscopy and first-principles calculations reveal a wide band gap variation in this material from 0 (bulk) to 1.3 eV (monolayer). The Raman-active vibrational modes of PdSe2 were identified using polarized Raman spectroscopy, and a strong interlayer interaction was revealed from large, thickness-dependent Raman peak shifts, agreeing with first-principles Raman simulations. Field-effect transistors made from the few-layer PdSe2 display tunable ambipolar charge carrier conduction with a high elec...
471 citations
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Smithsonian Conservation Biology Institute1, Smithsonian Tropical Research Institute2, National Museum of Natural History3, University of Alabama4, Stanford University5, Wilfrid Laurier University6, Mahidol University7, Department of National Parks, Wildlife and Plant Conservation8, University of Aberdeen9, University of Queensland10, Environmental Change Institute11, Xishuangbanna Tropical Botanical Garden12, University of Buea13, Indiana University14, United States Forest Service15, Indian Institute of Science16, Chinese Academy of Sciences17, National University of Colombia18, Forest Research Institute Malaysia19, University of California, Santa Cruz20, University of Peradeniya21, University of Hong Kong22, University of Alberta23, Oak Ridge National Laboratory24, University of Wisconsin–Green Bay25, University of California, Los Angeles26, College of Tropical Agriculture and Human Resources27, Wageningen University and Research Centre28, Kyoto University29, University of Nairobi30, Wildlife Conservation Society31, University of Montana32, Nanyang Technological University33, Utah State University34, Smithsonian Environmental Research Center35, Centre national de la recherche scientifique36, Natural England37, Washington University in St. Louis38, Academy of Sciences of the Czech Republic39, University of São Paulo40, University of the Philippines Diliman41, Harvard University42, University of Hawaii at Hilo43, Maejo University44, National Dong Hwa University45, University of Toronto46, Washington State University Vancouver47, University of Puerto Rico, Río Piedras48, Columbia University49, Pontificia Universidad Católica del Ecuador50, National Institute of Amazonian Research51, East China Normal University52, University of Minnesota53
TL;DR: The broad suite of measurements made at CTFS-ForestGEO sites makes it possible to investigate the complex ways in which global change is impacting forest dynamics, and continued monitoring will provide vital contributions to understanding worldwide forest diversity and dynamics in an era of global change.
Abstract: Global change is impacting forests worldwide, threatening biodiversity and ecosystem services including climate regulation. Understanding how forests respond is critical to forest conservation and climate protection. This review describes an international network of 59 long-term forest dynamics research sites (CTFS-ForestGEO) useful for characterizing forest responses to global change. Within very large plots (median size 25ha), all stems 1cm diameter are identified to species, mapped, and regularly recensused according to standardized protocols. CTFS-ForestGEO spans 25 degrees S-61 degrees N latitude, is generally representative of the range of bioclimatic, edaphic, and topographic conditions experienced by forests worldwide, and is the only forest monitoring network that applies a standardized protocol to each of the world's major forest biomes. Supplementary standardized measurements at subsets of the sites provide additional information on plants, animals, and ecosystem and environmental variables. CTFS-ForestGEO sites are experiencing multifaceted anthropogenic global change pressures including warming (average 0.61 degrees C), changes in precipitation (up to +/- 30% change), atmospheric deposition of nitrogen and sulfur compounds (up to 3.8g Nm(-2)yr(-1) and 3.1g Sm(-2)yr(-1)), and forest fragmentation in the surrounding landscape (up to 88% reduced tree cover within 5km). The broad suite of measurements made at CTFS-ForestGEO sites makes it possible to investigate the complex ways in which global change is impacting forest dynamics. Ongoing research across the CTFS-ForestGEO network is yielding insights into how and why the forests are changing, and continued monitoring will provide vital contributions to understanding worldwide forest diversity and dynamics in an era of global change.
470 citations
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TL;DR: In this paper, a framework for identifying useful indicators for quantifying the costs and benefits of agricultural systems for the range of ecosystem services interrelated to agriculture is presented. And the relationship between agricultural practices and land-use change and erosion impact on chemical use is also discussed.
469 citations
Authors
Showing all 32112 results
Name | H-index | Papers | Citations |
---|---|---|---|
Zhong Lin Wang | 245 | 2529 | 259003 |
Hyun-Chul Kim | 176 | 4076 | 183227 |
Bradley Cox | 169 | 2150 | 156200 |
Charles M. Lieber | 165 | 521 | 132811 |
Wei Li | 158 | 1855 | 124748 |
Joseph Jankovic | 153 | 1146 | 93840 |
James M. Tiedje | 150 | 688 | 102287 |
Peter Lang | 140 | 1136 | 98592 |
Andrew G. Clark | 140 | 823 | 123333 |
Josh Moss | 139 | 1019 | 89255 |
Robert H. Purcell | 139 | 666 | 70366 |
Ad Bax | 138 | 486 | 97112 |
George C. Schatz | 137 | 1155 | 94910 |
Daniel Thomas | 134 | 846 | 84224 |
Jerry M. Melillo | 134 | 383 | 68894 |