Warrington, United Kingdom
Warrington, United Kingdom

Daresbury Laboratory is a scientific research laboratory near Daresbury in Cheshire, England, which began operations in 1962 and was officially opened on 16 June 1967 as the Daresbury Nuclear Physics Laboratory by the then Prime Minister of United Kingdom, Harold Wilson. It is run by the Science and Technology Facilities Council with around three hundred full-time staff. Wikipedia.


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Zan R.,University of Manchester | Ramasse Q.M.,Daresbury Laboratory | Bangert U.,University of Manchester | Novoselov K.S.,University of Manchester
Nano Letters | Year: 2012

Nanoholes, etched under an electron beam at room temperature in single-layer graphene sheets as a result of their interaction with metal impurities, are shown to heal spontaneously by filling up with either nonhexagon, graphene-like, or perfect hexagon 2D structures. Scanning transmission electron microscopy was employed to capture the healing process and study atom-by-atom the regrown structure. A combination of these nanoscale etching and reknitting processes could lead to new graphene tailoring approaches. © 2012 American Chemical Society.


Winter G.,Diamond Light Source | Winter G.,Daresbury Laboratory | Winter G.,University of Manchester
Journal of Applied Crystallography | Year: 2010

An expert system for macromolecular crystallography data reduction is presented, which builds on existing software to automate the complete data reduction process from images to merged structure factor amplitudes. This can automatically identify multi-wedge, multi-pass and multiwavelength data sets and includes explicit procedures to test for crystallographic special cases. With the push towards high-thoughput crystallography at synchrotron beamlines and automation of structure solution, the ability to reduce data with no user input fills an important gap in the pipeline. © 2010 International Union of Crystallography Printed in Singapore-all rights reserved.


Zan R.,University of Manchester | Bangert U.,University of Manchester | Ramasse Q.,Daresbury Laboratory | Novoselov K.S.,University of Manchester
Nano Letters | Year: 2011

Distributions and atomic sites of transition metals and gold on suspended graphene were investigated via high-resolution scanning transmission electron microscopy, especially using atomic resolution high angle dark field imaging. All metals, albeit as singular atoms or atom aggregates, reside in the omni-present hydrocarbon surface contamination; they do not form continuous films, but clusters or nanocrystals. No interaction was found between Au atoms and clean single-layer graphene surfaces, i.e., no Au atoms are retained on such surfaces. Au and also Fe atoms do, however, bond to clean few-layer graphene surfaces, where they assume T and B sites, respectively. Cr atoms were found to interact more strongly with clean monolayer graphene, they are possibly incorporated at graphene lattice imperfections and have been observed to catalyze dissociation of C-C bonds. This behavior might explain the observed high frequency of Cr-cluster nucleation, and the usefulness as wetting layer, for depositing electrical contacts on graphene. © 2011 American Chemical Society.


Grant
Agency: GTR | Branch: Innovate UK | Program: | Phase: Collaborative Research & Development | Award Amount: 222.55K | Year: 2014

The goal is to accelerate the introduction of new & better products into the market by the simulation of manufacturing processes for complex multiphase liquid products for fast moving consumer goods (FMCG), including skin care and food. The project team consists of Unilever, CDDMtec an SME with a novel mixing platform, the University of Manchester Modelling and Simulation Centre and Science and Technology Facilities Council (STFC) at Sci-Tech Daresbury. The technical challenge is the development of Computation Fluid Dynamics (CFD) to incorporate the evolving non-Newtonian liquid rheology as the product is assembled and processed. This requires the construction of coupled models detailing how the interaction of materials, process and equipment design affect product rheology and performance. The results of the simulations will be tested through rapid prototyping (eg 3D printing) of promising concepts.


Tomic S.,Daresbury Laboratory
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

We present a theoretical model for design and analysis of semiconductor quantum dot (QD) array-based intermediate-band solar cell (IBSC). The plane-wave method with periodic boundary conditions is used in expansion of the k·p Hamiltonian for calculation of the electronic and optical structures of InAs/GaAs QD array. Taking into account realistic QD shape, QD periodicity in the array, as well as effects such as band mixing between states in the conduction and valence band, strain and piezoelectric field, the model reveals the origin of the intermediate-band formation inside forbidden energy gap of the barrier material. Having established the interrelation between QD periodicity and the electronic structure across the QD array Brillouin zone, conditions are identified for the appearance of pure zero density-of-states regions, that separate intermediate band from the rest of the conduction band. For one realistic QD array we have estimated all important absorption coefficients in IBSC, and most important, radiative and nonradiative scattering times. Under radiative-limit approximation we have estimated efficiency of such IBSC to be 39%. © 2010 The American Physical Society.


Metz S.,Daresbury Laboratory | Thiel W.,Max-Planck-Institut für Kohlenforschung
Coordination Chemistry Reviews | Year: 2011

In recent years, advances in theoretical methods and computational capabilities have made it possible to investigate reaction mechanisms in enzymes. Density functional theory (DFT) is commonly used to study reactions in model systems, while combined quantum mechanical/molecular mechanical (QM/MM) approaches allow the treatment of the complete solvated enzyme and thus provide insight into the mechanistic influence of the protein environment. This review starts with a brief overview over the available DFT and QM/MM methodology and then summarizes recent theoretical studies on biocatalysis by molybdenum-containing enzymes. It focuses on the reactions in members of the dimethylsulfoxide reductase, sulfite oxidase, and xanthine oxidase families, with special emphasis on the QM/MM studies of the latter. It concludes with a brief survey of theoretical work on some other molybdenum- and tungsten-containing enzymes. © 2011 Elsevier B.V.


Morris C.,Daresbury Laboratory
Acta Crystallographica Section D: Biological Crystallography | Year: 2013

This is an introduction to four papers based on presentations given at a workshop entitled Integrated Software for Integrative Structural Biology. The use of hybrid techniques, and other trends in structural research, pose new challenges to software developers. A structural biology work bench that meets these needs would provide seamless data transfer between processing steps, and accumulate archival data and metadata without intruding into the scientist's work process. © 2013 International Union of Crystallography Printed in Singapore - all rights reserved.


Mcneil B.W.J.,University of Strathclyde | Thompson N.R.,Daresbury Laboratory
Nature Photonics | Year: 2010

With intensities 108-1010 times greater than other laboratory sources, X-ray free-electron lasers are currently opening up new frontiers across many areas of science. In this Review we describe how these unconventional lasers work, discuss the range of new sources being developed worldwide, and consider how such X-ray sources may develop over the coming years. © 2010 Macmillan Publishers Limited. All rights reserved.


Shang Z.,Daresbury Laboratory
Computer Physics Communications | Year: 2013

In order to run computational fluid dynamics (CFD) codes on large scales, parallel computing has to be employed. For instance, on Petascale computing, general parallel computing without any optimization is not enough, especially for complex industrial issues that employ a large number of mesh cells to capture the details of the geometry. How to distribute these mesh cells among the multi-processors for Terascale and Petascale systems to obtain a good performance on parallel computing is really a challenge. Some mesh partitioning software packages, such as Metis, ParMetis, PT-Scotch and Zoltan, were chosen as the candidates ported into CodeSaturne to test if they can lead CodeSaturne towards Petascale and Exascale parallel CFD computing. Through the studies, it was found that mesh partitioning optimization software packages based on the graph mesh partitioning method can help the CFD code obtain good mesh distributions for high performance computing (HPC). © 2012 Elsevier B.V. All rights reserved.


Geaney H.,University of Limerick | Mullane E.,University of Limerick | Ramasse Q.M.,Daresbury Laboratory | Ryan K.M.,University of Limerick
Nano Letters | Year: 2013

The growth of Si/Ge axial heterostructure nanowires in high yield using a versatile wet chemical approach is reported. Heterostructure growth is achieved using the vapor zone of a high boiling point solvent as a reaction medium with an evaporated tin layer as the catalyst. The low solubility of Si and Ge within the Sn catalyst allows the formation of extremely abrupt heterojunctions of the order of just 1-2 atomic planes between the Si and Ge nanowire segments. The compositional abruptness was confirmed using aberration corrected scanning transmission electron microscopy and atomic level electron energy loss spectroscopy. Additional analysis focused on the role of crystallographic defects in determining interfacial abruptness and the preferential incorporation of metal catalyst atoms near twin defects in the nanowires. © 2013 American Chemical Society.

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