Institution
Sandia National Laboratories
Facility•Livermore, California, United States•
About: Sandia National Laboratories is a facility organization based out in Livermore, California, United States. It is known for research contribution in the topics: Laser & Combustion. The organization has 21501 authors who have published 46724 publications receiving 1484388 citations. The organization is also known as: SNL & Sandia National Labs.
Topics: Laser, Combustion, Thin film, Hydrogen, Finite element method
Papers published on a yearly basis
Papers
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TL;DR: This work unambiguously solves the structure of molybdenum disulfide monolayer monolayers using high-resolution transmission electron microscopy supported by density functional theory and shows lithium intercalation to direct a preferential transformation of the basal plane from 2H (trigonal prismatic) to 1T′ (clustered Mo).
Abstract: Establishing processing–structure–property relationships for monolayer materials is crucial for a range of applications spanning optics, catalysis, electronics and energy. Presently, for molybdenum disulfide, a promising catalyst for artificial photosynthesis, considerable debate surrounds the structure/property relationships of its various allotropes. Here we unambiguously solve the structure of molybdenum disulfide monolayers using high-resolution transmission electron microscopy supported by density functional theory and show lithium intercalation to direct a preferential transformation of the basal plane from 2H (trigonal prismatic) to 1T′ (clustered Mo). These changes alter the energetics of molybdenum disulfide interactions with hydrogen (ΔGH), and, with respect to catalysis, the 1T′ transformation renders the normally inert basal plane amenable towards hydrogen adsorption and hydrogen evolution. Indeed, we show basal plane activation of 1T′ molybdenum disulfide and a lowering of ΔGH from +1.6 eV for 2H to +0.18 eV for 1T′, comparable to 2H molybdenum disulfide edges on Au(111), one of the most active hydrogen evolution catalysts known. Establishing structure–property relationships for catalytic materials is essential for optimization of performance. Here, the authors solve the structure of molybdenum disulfide monolayers, and probe the role of lithium intercalation and the subsequent effects on catalytic hydrogen activation.
253 citations
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01 Feb 2000TL;DR: The authors show that by adding additional inequalities, the ratio between the optimal integer solution and the optimal solution to the linear program relaxation can be improved significantly, and provide a polynomial-time approximation algorithm to achieve this bound.
Abstract: A capacitated covering IP is an integer program of the form min{l_brace}ex{vert_bar}Ux {ge} d, 0 {le} x {le} b, x {element_of} Z{sup +}{r_brace}, where all entries of c, U, and d are nonnegative. Given such a formulation, the ratio between the optimal integer solution and the optimal solution to the linear program relaxation can be as bad as {parallel}d{parallel}{sub {proportional_to}}, even when U consists of a single row. They show that by adding additional inequalities, this ratio can be improved significantly. In the general case, they show that the improved ratio is bounded by the maximum number of non-zero coefficients in a row of U, and provide a polynomial-time approximation algorithm to achieve this bound. This improves upon the results of Bertsimas and Vohra, strengthening their extension of Hall and Hochbaum.
253 citations
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TL;DR: In this article, the authors developed a cavity expansion penetration model for concrete targets based on idealized pressure-volumetric strain as incompressible or linear compressible and idealized shear strength-pressure as Mohr-Coulomb with a tension cutoff.
252 citations
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19 Nov 1997TL;DR: In this article, a method for integrating one or more microelectromechanical (MEM) devices with electronic circuitry on a common substrate is described, where the MEM device can be fabricated within a substrate cavity and encapsulated with a sacrificial material.
Abstract: A method is disclosed for integrating one or more microelectromechanical (MEM) devices with electronic circuitry on a common substrate. The MEM device can be fabricated within a substrate cavity and encapsulated with a sacrificial material. This allows the MEM device to be annealed and the substrate planarized prior to forming electronic circuitry on the substrate using a series of standard processing steps. After fabrication of the electronic circuitry, the electronic circuitry can be protected by a two-ply protection layer of titanium nitride (TiN) and tungsten (W) during an etch release process whereby the MEM device is released for operation by etching away a portion of a sacrificial material (e.g. silicon dioxide or a silicate glass) that encapsulates the MEM device. The etch release process is preferably performed using a mixture of hydrofluoric acid (HF) and hydrochloric acid (HCI) which reduces the time for releasing the MEM device compared to use of a buffered oxide etchant. After release of the MEM device, the TiN:W protection layer can be removed with a peroxide-based etchant without damaging the electronic circuitry.
252 citations
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TL;DR: In this paper, a unified analysis method for small-angle scattering data is demonstrated by surveying complex systems that display multiple size-scale structures using a function that is general enough to adequately describe systems ranging from particulates with fractally rough interfaces to mass fractals such as polymer coils.
Abstract: A unified analysis method for small-angle scattering data is demonstrated by surveying complex systems that display multiple size-scale structures. Using this approach the relationship between micro- and nano-structures can be ascertained. The method uses a function that is general enough to adequately describe systems ranging from particulates with fractally rough interfaces to mass fractals such as polymer coils. Additionally multiple Guinier and power-law regimes can be treated. The unified method can distinguish Guinier regimes buried between two power-law regimes. Data from particulate filled systems, low crystallinity polymers and low density polymer foams are analyzed.
252 citations
Authors
Showing all 21652 results
Name | H-index | Papers | Citations |
---|---|---|---|
Lily Yeh Jan | 162 | 467 | 73655 |
Jongmin Lee | 150 | 2257 | 134772 |
Jun Liu | 138 | 616 | 77099 |
Gerbrand Ceder | 137 | 682 | 76398 |
Kevin M. Smith | 114 | 1711 | 78470 |
Henry F. Schaefer | 111 | 1611 | 68695 |
Thomas Bein | 109 | 677 | 42800 |
David Chandler | 107 | 424 | 52396 |
Stephen J. Pearton | 104 | 1913 | 58669 |
Harold G. Craighead | 101 | 569 | 40357 |
Edward Ott | 101 | 669 | 44649 |
S. Das Sarma | 100 | 951 | 58803 |
Richard M. Crooks | 97 | 419 | 31105 |
David W. Murray | 97 | 699 | 43372 |
Alán Aspuru-Guzik | 97 | 628 | 44939 |