Molecules in the mirror: how SERS backgrounds arise from the quantum method of images

The Raman coupling of light to molecular vibrations is strongly modified when they are placed near a plasmonic metal surface, with the appearance of a strong broad continuum background in addition to the normal surface-enhanced Raman scattering (SERS) peaks. Using a quantum method of images approach, we produce a simple but quantitative explanation of the inevitable presence of the background, due to the resistive damping of the image molecule. This model thus suggests new strategies for enhancing the SERS peak to background ratio

Molecules in the mirror: how SERS backgrounds arise from the quantum method of images.

The Raman coupling of light to molecular vibrations is strongly modified when they are placed near a plasmonic metal surface, with the appearance of a strong broad continuum background in addition to the normal surface-enhanced Raman scattering (SERS) peaks. Using a quantum method of images approach, we produce a simple but quantitative explanation of the inevitable presence of the background, due to the resistive damping of the image molecule. This model thus suggests new strategies for enhancing the SERS peak to background ratio.This work was supported by UK EPSRC EP/C511786/1, EP/F011393, ERC 320503 LINASS, EU CUBIHOLES, 3M, the Royal Society and the Wolfson Foundation

CO2 Transport Systems Development: Status of Three Large European CCS Demonstration Projects with EEPR Funding

AbstractThis paper addresses technical and operational aspects pertaining to the transport of CO2. It deals with lessons learnt from the development of three large CCS demonstration projects: the UK-based Don Valley project, the Dutch ROAD project, and the Spanish Compostilla project. These projects were all selected by the European Commission in 2009 to receive funding under the European Energy Programme for Recovery (EEPR). The purpose of the demonstration projects is to verify feasible capture techniques (i.e. gasification, flue-gas cleaning, and oxy-coal combustion in circulating fluidised bed, respectively), and to demonstrate geological storage options, off-shore and on-shore. As the distance and elevation of the CO2 transport system are inherently given by the project, the transport conditions for the CO2 will generally differ from one project to another.The demonstration projects have shown that the thermophysical nature of CO2 is prone to complicate certain operational procedures mainly due to phenomena like phase change, hydrate formation and Joule-Thomson cooling. The front-end engineering design studies suggest, however, that the handling of CO2 is quite feasible during normal operation, although customised solutions may be required to handle transients like emergency shut-down and pipeline re-pressurisation. This implies that CO2 transport is not seen as an insuperable hurdle to the design and operation of large CCS systems

Contracting the Facebook API

In recent years, there has been an explosive growth in the popularity of online social networks such as Facebook. In a new twist, third party developers are now able to create their own web applications which plug into Facebook and work with Facebook's "social" data, enabling the entire Facebook user base of more than 400 million active users to use such applications. These client applications can contain subtle errors that can be hard to debug if they misuse the Facebook API. In this paper we present an experience report on applying Microsoft's new code contract system for the .NET framework to the Facebook API.We wrote contracts for several classes in the Facebook API wrapper which allows Microsoft .NET developers to implement Facebook applications. We evaluated the usefulness of these contracts during implementation of a new Facebook application. Our experience indicates that having code contracts provides a better and quicker software development experience.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330

A Parallel Non-Uniform Fast Fourier Transform Library Based on an "Exponential of Semicircle" Kernel

The nonuniform fast Fourier transform (NUFFT) generalizes the FFT to off-grid data. Its many applications include image reconstruction, data analysis, and the numerical solution of differential equations. We present FINUFFT, an efficient parallel library for type 1 (nonuniform to uniform), type 2 (uniform to nonuniform), or type 3 (nonuniform to nonuniform) transforms, in dimensions 1, 2, or 3. It uses minimal RAM, requires no precomputation or plan steps, and has a simple interface to several languages. We perform the expensive spreading/interpolation between nonuniform points and the fine grid via a simple new kernel---the ``exponential of semicircle"" e beta surd 1 - x2 in x in [ - 1, 1]---in a cache-aware load-balanced multithreaded implementation. The deconvolution step requires the Fourier transform of the kernel, for which we propose efficient numerical quadrature. For types 1 and 2, rigorous error bounds asymptotic in the kernel width approach the fastest known exponential rate, namely that of the Kaiser--Bessel kernel. We benchmark against several popular CPU-based libraries, showing favorable speed and memory footprint, especially in three dimensions when high accuracy and/or clustered point distributions are desired

The Future of Cybercrime: AI and Emerging Technologies Are Creating a Cybercrime Tsunami

This paper reviews the impact of AI and emerging technologies on the future of cybercrime and the necessary strategies to combat it effectively. Society faces a pressing challenge as cybercrime proliferates through AI and emerging technologies. At the same time, law enforcement and regulators struggle to keep it up. Our primary challenge is raising awareness as cybercrime operates within a distinct criminal ecosystem. We explore the hijacking of emerging technologies by criminals (CrimeTech) and their use in illicit activities, along with the tools and processes (InfoSec) to protect against future cybercrime. We also explore the role of AI and emerging technologies (DeepTech) in supporting law enforcement, regulation, and legal services (LawTech)