Institution
Queen's University Belfast
Education•Belfast, United Kingdom•
About: Queen's University Belfast is a education organization based out in Belfast, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 25457 authors who have published 55463 publications receiving 1751346 citations. The organization is also known as: Queen's College, Belfast & Queen's College.
Topics: Population, Context (language use), Laser, Catalysis, Ionic liquid
Papers published on a yearly basis
Papers
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TL;DR: O(2) dissociation on Au surfaces including particles cannot occur at low temperatures, and it is suggested that CO oxidation on Au/active-materials also follows the two-step mechanism with reactions occurring at the interface.
Abstract: Gold-based catalysts have been of intense interests in recent years, being regarded as a new generation of catalysts due to their unusually high catalytic performance. For example, CO oxidation on Au/TiO(2) has been found to occur at a temperature as low as 200 K. Despite extensive studies in the field, the microscopic mechanism of CO oxidation on Au-based catalysts remains controversial. Aiming to provide insight into the catalytic roles of Au, we have performed extensive density functional theory calculations for the elementary steps in CO oxidation on Au surfaces. O atom adsorption, CO adsorption, O(2) dissociation, and CO oxidation on a series of Au surfaces, including flat surfaces, defects and small clusters, have been investigated in detail. Many transition states involved are located, and the lowest energy pathways are determined. We find the following: (i) the most stable site for O atom on Au is the bridge site of step edge, not a kink site; (ii) O(2) dissociation on Au (O(2)-->2O(ad)) is hindered by high barriers with the lowest barrier being 0.93 eV on a step edge; (iii) CO can react with atomic O with a substantially lower barrier, 0.25 eV, on Au steps where CO can adsorb; (iv) CO can react with molecular O(2) on Au steps with a low barrier of 0.46 eV, which features an unsymmetrical four-center intermediate state (O-O-CO); and (v) O(2) can adsorb on the interface of Au/TiO(2) with a reasonable chemisorption energy. On the basis of our calculations, we suggest that (i) O(2) dissociation on Au surfaces including particles cannot occur at low temperatures; (ii) CO oxidation on Au/inactive-materials occurs on Au steps via a two-step mechanism: CO+O(2)-->CO(2)+O, and CO+O-->CO(2); and (iii) CO oxidation on Au/active-materials also follows the two-step mechanism with reactions occurring at the interface.
500 citations
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TL;DR: The R-matrix concept of atomic processes was first introduced by Wigner and Eisenbud as mentioned in this paper with the fundamental idea that configuration space describes the scattered particle, and the target is divided into two regions.
Abstract: Publisher Summary This chapter discusses the R-matrix concept of atomic processes. The R-matrix method was first introduced by Wigner and Eisenbud with a fundamental idea that configuration space describes the scattered particle, and the target is divided into two regions. In the internal region (r
498 citations
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TL;DR: There is evidence of increasing frequency of MG with year of study and improved study quality, which probably reflects improved case ascertainment and other factors must also influence disease onset resulting in the observed variation in IR across geographically and genetically similar populations.
Abstract: The aim was to collate all myasthenia gravis (MG) epidemiological studies including AChR MG and MuSK MG specific studies. To synthesize data on incidence rate (IR), prevalence rate (PR) and mortality rate (MR) of the condition and investigate the influence of environmental and technical factors on any trends or variation observed. Studies were identified using multiple sources and meta-analysis performed to calculate pooled estimates for IR, PR and MR. 55 studies performed between 1950 and 2007 were included, representing 1.7 billion population-years. For All MG estimated pooled IR (eIR): 5.3 per million person-years (C.I.:4.4, 6.1), range: 1.7 to 21.3; estimated pooled PR: 77.7 per million persons (C.I.:64.0, 94.3), range 15 to 179; MR range 0.1 to 0.9 per millions person-years. AChR MG eIR: 7.3 (C.I.:5.5, 7.8), range: 4.3 to 18.0; MuSK MG IR range: 0.1 to 0.32. However marked variation persisted between populations studied with similar methodology and in similar areas. We report marked variation in observed frequencies of MG. We show evidence of increasing frequency of MG with year of study and improved study quality. This probably reflects improved case ascertainment. But other factors must also influence disease onset resulting in the observed variation in IR across geographically and genetically similar populations.
498 citations
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University College London1, University of Helsinki2, Finnish Institute of Occupational Health3, French Institute of Health and Medical Research4, Stockholm University5, Karolinska Institutet6, RMIT University7, Stockholm County Council8, Federal Institute for Occupational Safety and Health9, Université libre de Bruxelles10, Ghent University11, University of Düsseldorf12, University of Duisburg-Essen13, Mid Sweden University14, Umeå University15, University of Copenhagen16, University of Turku17, University of Skövde18, Turku University Hospital19, Uppsala University20, Queen's University Belfast21, University of Essex22, University of Edinburgh23, University of Bristol24
TL;DR: Employees who work long hours have a higher risk of stroke than those working standard hours; the association with coronary heart disease is weaker; these findings suggest that more attention should be paid to the management of vascular risk factors in individuals whoWork long hours.
497 citations
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01 Mar 2018TL;DR: This work considers the cell-free massive multiple-input multiple-output (MIMO) downlink, where a very large number of distributed multiple-antenna access points (APs) serve many single-ant antenna users in the same time-frequency resource, and derives a closed-form expression for the spectral efficiency taking into account the effects of channel estimation errors and power control.
Abstract: We consider the cell-free massive multiple-input multiple-output (MIMO) downlink, where a very large number of distributed multiple-antenna access points (APs) serve many single-antenna users in the same time-frequency resource. A simple (distributed) conjugate beamforming scheme is applied at each AP via the use of local channel state information (CSI). This CSI is acquired through time-division duplex operation and the reception of uplink training signals transmitted by the users. We derive a closed-form expression for the spectral efficiency taking into account the effects of channel estimation errors and power control. This closed-form result enables us to analyze the effects of backhaul power consumption, the number of APs, and the number of antennas per AP on the total energy efficiency, as well as, to design an optimal power allocation algorithm. The optimal power allocation algorithm aims at maximizing the total energy efficiency, subject to a per-user spectral efficiency constraint and a per-AP power constraint. Compared with the equal power control, our proposed power allocation scheme can double the total energy efficiency. Furthermore, we propose AP selections schemes, in which each user chooses a subset of APs, to reduce the power consumption caused by the backhaul links. With our proposed AP selection schemes, the total energy efficiency increases significantly, especially for large numbers of APs. Moreover, under a requirement of good quality-of-service for all users, cell-free massive MIMO outperforms the colocated counterpart in terms of energy efficiency.
497 citations
Authors
Showing all 25808 results
Name | H-index | Papers | Citations |
---|---|---|---|
George Davey Smith | 224 | 2540 | 248373 |
David J. Hunter | 213 | 1836 | 207050 |
Grant W. Montgomery | 157 | 926 | 108118 |
Caroline S. Fox | 155 | 599 | 138951 |
Debbie A Lawlor | 147 | 1114 | 101123 |
Markus Ackermann | 146 | 610 | 71071 |
Hermann Kolanoski | 145 | 1279 | 96152 |
Paul Jackson | 141 | 1372 | 93464 |
Alan Ashworth | 134 | 578 | 72089 |
Conor Henderson | 133 | 1387 | 88725 |
David Smith | 129 | 2184 | 100917 |
Stuart J. Connolly | 125 | 610 | 75925 |
G. Merino | 123 | 687 | 66163 |
Richard J.H. Smith | 118 | 1308 | 61779 |
Yong-Guan Zhu | 115 | 684 | 46973 |