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Oak Ridge National Laboratory

FacilityOak Ridge, Tennessee, United States
About: Oak Ridge National Laboratory is a(n) facility organization based out in Oak Ridge, Tennessee, United States. It is known for research contribution in the topic(s): Neutron & Neutron scattering. The organization has 31868 authors who have published 73724 publication(s) receiving 2633689 citation(s). The organization is also known as: ORNL.

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Journal ArticleDOI
Abstract: The indentation load-displacement behavior of six materials tested with a Berkovich indenter has been carefully documented to establish an improved method for determining hardness and elastic modulus from indentation load-displacement data. The materials included fused silica, soda–lime glass, and single crystals of aluminum, tungsten, quartz, and sapphire. It is shown that the load–displacement curves during unloading in these materials are not linear, even in the initial stages, thereby suggesting that the flat punch approximation used so often in the analysis of unloading data is not entirely adequate. An analysis technique is presented that accounts for the curvature in the unloading data and provides a physically justifiable procedure for determining the depth which should be used in conjunction with the indenter shape function to establish the contact area at peak load. The hardnesses and elastic moduli of the six materials are computed using the analysis procedure and compared with values determined by independent means to assess the accuracy of the method. The results show that with good technique, moduli can be measured to within 5%.

20,195 citations

Journal ArticleDOI
Abstract: A new hybrid exchange–correlation functional named CAM-B3LYP is proposed. It combines the hybrid qualities of B3LYP and the long-range correction presented by Tawada et al. [J. Chem. Phys., in press]. We demonstrate that CAM-B3LYP yields atomization energies of similar quality to those from B3LYP, while also performing well for charge transfer excitations in a dipeptide model, which B3LYP underestimates enormously. The CAM-B3LYP functional comprises of 0.19 Hartree–Fock (HF) plus 0.81 Becke 1988 (B88) exchange interaction at short-range, and 0.65 HF plus 0.35 B88 at long-range. The intermediate region is smoothly described through the standard error function with parameter 0.33.

8,975 citations

Journal ArticleDOI
TL;DR: GROMACS is one of the most widely used open-source and free software codes in chemistry, used primarily for dynamical simulations of biomolecules, and provides a rich set of calculation types.
Abstract: GROMACS is one of the most widely used open-source and free software codes in chemistry, used primarily for dynamical simulations of biomolecules. It provides a rich set of calculation types, prepa ...

8,050 citations

Journal ArticleDOI
Curtis Huttenhower1, Curtis Huttenhower2, Dirk Gevers2, Rob Knight3  +250 moreInstitutions (42)
14 Jun 2012-Nature
Abstract: The Human Microbiome Project Consortium reports the first results of their analysis of microbial communities from distinct, clinically relevant body habitats in a human cohort; the insights into the microbial communities of a healthy population lay foundations for future exploration of the epidemiology, ecology and translational applications of the human microbiome.

6,805 citations

Journal ArticleDOI
Abstract: The method we introduced in 1992 for measuring hardness and elastic modulus by instrumented indentation techniques has widely been adopted and used in the characterization of small-scale mechanical behavior. Since its original development, the method has undergone numerous refinements and changes brought about by improvements to testing equipment and techniques as well as from advances in our understanding of the mechanics of elastic–plastic contact. Here, we review our current understanding of the mechanics governing elastic–plastic indentation as they pertain to load and depth-sensing indentation testing of monolithic materials and provide an update of how we now implement the method to make the most accurate mechanical property measurements. The limitations of the method are also discussed.

5,764 citations


Showing all 31868 results

Zhong Lin Wang2452529259003
Hyun-Chul Kim1764076183227
Bradley Cox1692150156200
Charles M. Lieber165521132811
Wei Li1581855124748
Joseph Jankovic153114693840
James M. Tiedje150688102287
Peter Lang140113698592
Andrew G. Clark140823123333
Josh Moss139101989255
Robert H. Purcell13966670366
Ad Bax13848697112
George C. Schatz137115594910
Daniel Thomas13484684224
Jerry M. Melillo13438368894
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