1,721,508 research outputs found
Nonlinear Ptychographic coherent diffractive imaging
No full textPtychographic Coherent Diffractive Imaging (PCDI) is
a significant advance in imaging allowing the measurement of the full electric field at a sample without use of any imaging optics. So far it has been confined solely to imaging of linear optical responses. In this paper we show that because of the coherence-preserving nature of nonlinear optical interactions, PCDI can be generalised to nonlinear optical imaging. We demonstrate second harmonic generation PCDI, directly revealing phase information about the nonlinear coefficients, and showing the general applicability of PCDI to nonlinear interactions.
Data supports the paper "Odstrcil, Michal, Baksh, Peter, Gawith, Corin, Vrcelj, Ranko, Frey, Jeremy and Brocklesby, William (2016) Nonlinear ptychographic coherent diffractive imaging. Optics Express"</span
Science ajar: how e-science can help (more) open science
No full textMy talk will look at how varying degrees of openness aid scientific collaboration with the underlying theme that accurate recording of process and data in experiments is essential. I will take the view that the laboratory, equipment and people are potentially equal partners in this process, which can be facilitated by the right choice of software. I will discuss how the developments of the Web and the Semantic Web have changed the way we can enable collaborations especially for long tail science generating large amounts of heterogeneous data
A new topological descriptor for water network structure
Full text linkBulk water molecular dynamics simulations based on a series of atomistic water potentials (TIP3P, TIP4P/Ew, SPC/E and OPC) are compared using new techniques from the field of topological data analysis. The topological invariants (the different degrees of homology) derived from each simulation frame are used to create a series of persistence diagrams from the atomic positions. These are averaged over the simulation time using the persistence image formalism, before being normalised by their total magnitude (the L1 norm) to ensure a size independent descriptor (L1NPI). We demonstrate that the L1NPI formalism is suitable for the analysis of systems where the number of molecules varies by at least a factor of 10. Using standard machine learning techniques, a basic linear SVM, it is shown that differences in water models are able to be isolated to different degrees of homology. In particular, whereas first degree homology is able to distinguish between all atomistic potentials studied, OPC is the only potential that differs in its second degree homology. The L1 normalised persistence images are then used in the comparison of a series of Stillinger–Weber potential simulations to the atomistic potentials and the effects of changing the strength of three-body interactions on the structures is easily evident in L1NPI space, with a reduction in variance of structures as interaction strength increases being the most obvious result. Furthermore, there is a clear tracking in L1NPI space of the λ parameter. The L1NPI formalism presents a useful new technique for the analysis of water and other materials. It is approximately size-independent, and has been shown to contain information as to real structures in the system. We finally present a perspective on the use of L1NPIs and other persistent homology techniques as a descriptor for water solubility
Curation of laboratory experimental data as part of the overall data lifecycle
Full text linkThe explosion in the production of scientific data in recent years is placing strains upon conventional systems supporting integration, analysis, interpretation and dissemination of data and thus constraining the whole scientific process. Support for handling large quantities of diverse information can be provided by e-Science methodologies and the cyber-infrastructure that enables collaborative handling of such data. Regard needs to be taken of the whole process involved in scientific discovery. This includes the consideration of the requirements of the users and consumers further down the information chain and what they might ideally prefer to impose on the generators of those data. As the degree of digital capture in the laboratory increases, it is possible to improve the automatic acquisition of the ‘context of the data’ as well as the data themselves. This process provides an opportunity for the data creators to ensure that many of the problems they often encounter in later stages are avoided. We wish to elevate curation to an operation to be considered by the laboratory scientist as part of good laboratory practice, not a procedure of concern merely to the few specialising in archival processes. Designing curation into experiments is an effective solution to the provision of high-quality metadata that leads to better, more re-usable data and to better science
Physical Science Research Spaces: Key issues for science researchers
No full textThe relationship between physical science research in universities and libraries is discussed looking at issues raised by the location and nature of the research, details how and where do we find, access and interact with, research materials? How do we deposit research data (and what do we deposit) and the influence of the growing dominance of the e-World
From open access to intelligently accessible data in Open Notebooks
No full textProgress in science depends on access to results and data from earlier work. E-Science and Web 2.0 have in principle provided new tools to enable the communication of data that underpins scientific discovery. Professor Frey will explore the ways in which the open agenda serves to improve productivity and reduce and manage uncertainty and consider if “Open Science” was and is an inevitable outcome of the e-Science programme”
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