He Scattering from Compact Clusters and from Diffusion-Limited Aggregates on Surfaces: Observable Signatures of Structure

The angular intensity distribution of He beams scattered from compact clusters and from diffusion limited aggregates, epitaxially grown on metal surfaces, is investigated theoretically. The purpose is twofold: to distinguish compact cluster structures from diffusion limited aggregates, and to find observable {\em signatures} that can characterize the compact clusters at the atomic level of detail. To simplify the collision dynamics, the study is carried out in the framework of the sudden approximation, which assumes that momentum changes perpendicular to the surface are large compared with momentum transfer due to surface corrugation. The diffusion limited aggregates on which the scattering calculations were done, were generated by kinetic Monte Carlo simulations. It is demonstrated, by focusing on the example of compact Pt Heptamers, that signatures of structure of compact clusters may indeed be extracted from the scattering distribution. These signatures enable both an experimental distinction between diffusion limited aggregates and compact clusters, and a determination of the cluster structure. The characteristics comprising the signatures are, to varying degrees, the Rainbow, Fraunhofer, specular and constructive interference peaks, all seen in the intensity distribution. It is also shown, how the distribution of adsorbate heights above the metal surface can be obtained by an analysis of the specular peak attenuation. The results contribute to establishing He scattering as a powerful tool in the investigation of surface disorder and epitaxial growth on surfaces, alongside with STM.Comment: 41 pages, 16 postscript figures. For more details see http://www.fh.huji.ac.il/~dan

Using Automatic Static Analysis to Identify Technical Debt

The technical debt (TD) metaphor describes a tradeoff between short-term and long-term goals in software development. Developers, in such situations, accept compromises in one dimension (e.g. maintainability) to meet an urgent demand in another dimension (e.g. delivering a release on time). Since TD produces interests in terms of time spent to correct the code and accomplish quality goals, accumulation of TD in software systems is dangerous because it could lead to more difficult and expensive maintenance. The research presented in this paper is focused on the usage of automatic static analysis to identify Technical Debt at code level with respect to different quality dimensions. The methodological approach is that of Empirical Software Engineering and both past and current achieved results are presented, focusing on functionality, efficiency and maintainabilit

Agent-based simulation of electricity markets: a literature review

Liberalisation, climate policy and promotion of renewable energy are challenges to players of the electricity sector in many countries. Policy makers have to consider issues like market power, bounded rationality of players and the appearance of fluctuating energy sources in order to provide adequate legislation. Furthermore the interactions between markets and environmental policy instruments become an issue of increasing importance. A promising approach for the scientific analysis of these developments is the field of agent-based simulation. The goal of this article is to provide an overview of the current work applying this methodology to the analysis of electricity markets. --

ERNST: Demonstrating Advanced Infrared Detection from a 12U CubeSat

The ERNST mission will demonstrate complex infrared detection capabilities using a 12U CubeSat platform. ERNST’s main payload is an advanced cryogenically-cooled infrared imager that implicates demanding requirements in terms of power demand, heat dissipation, and vibration response for a nanosatellite. The optical bench that integrates optics, a filter-wheel for switching between spectral bands, and the detector-cooler system has been additively designed and manufactured, giving it a bionic appearance and combined with a highly efficient radiator. An onboard radiation monitor and a COTS camera complete the mission payloads. The ERNST 12U platform is based on high-performance CubeSat subsystems for avionics, UHF, and X-band communication, attitude control, and power management. The commercial components are made compatible through a backplane solution. In-house developments include a fast DPU and an autonomous de-orbit dragsail. The platform provides 30 Watt (OAP) and \u3e6U payload volume. After comprehensive environmental and functional testing of the Engineering Model, the Flight Model is currently being integrated. Starting operations in February 2023, ERNST will verify early warning concepts and technology

Managing the interface between public sector applied research and technological development in the Chinese enterprise sector

China's technological capabilities are emerging rapidly and the country will become a major challenger to established nations in terms of R&D and innovation in the near future. For the moment, however, contradictory signals emerge from the Chinese economy leaving experts pondering about the country's true potential for technological upgrading on a broad scale. The integration of the domestic research system, international technology transfer, and technological development remains limited to a few high-tech companies, while large segments of the domestic private sector have limited access to knowledge and technologies to upgrade their activities. --China,Guangdong,interface,knowledge supply,knowledge demand,regional innovation system,science-industry relations

Public research spin-offs in Germany: Summary report

The growing importance of knowledge and the ensuing need to translate research results, and especially new scientific findings as quickly as possible into economic activities are drawing the attention of academia and politicans increasingly towards what is referred to as academic spin-off formations. These business foundations from higher education institutions and off-campus research facilities are a route to knowledge and technology transfer, which can ensure that the research results gathered in these facilities are transferred directly into marketable products or processes. Policymakers are expected to create favourable framework conditions for the formation of spin-offs. Several initiatives of the Federal State and Länder (e.g. the EXIST Programme of the BMBF) were started with the express goal of promoting and aiding such new businesses. --

Optical data processing using paraboloidal mirror segments

An optical data processing system using paraboloidal reflecting surfaces is disclosed. In the preferred embodiment the paraboloidal reflecting surfaces are segments of a paraboloidal mirror. A source of coherent light is in the focal plane of the first paraboloidal mirror segment which collimates the beam and reflects it toward a second paraboloidal mirror surface. The information to be analyzed, on a transparency for example, is placed in the collimated beam. The beam is reflected from the second paraboloidal mirror segment and focused on a Fourier transform plane. A photon detector could be placed in the Fourier transform plane or suitable spatial filters, with the filtered beam then being reflected from a third paraboloidal mirror segment to be focused on a reconstruction plane

Simultaneous multislice acquisition with multi-contrast segmented EPI for separation of signal contributions in dynamic contrast-enhanced imaging

We present a method to efficiently separate signal in magnetic resonance imaging (MRI) into a base signal S0, representing the mainly T1-weighted component without T2*-relaxation, and its T2*-weighted counterpart by the rapid acquisition of multiple contrasts for advanced pharmacokinetic modelling. This is achieved by incorporating simultaneous multislice (SMS) imaging into a multi-contrast, segmented echo planar imaging (EPI) sequence to allow extended spatial coverage, which covers larger body regions without time penalty. Simultaneous acquisition of four slices was combined with segmented EPI for fast imaging with three gradient echo times in a preclinical perfusion study. Six female domestic pigs, German-landrace or hybrid-form, were scanned for 11 minutes respectively during administration of gadolinium-based contrast agent. Influences of reconstruction methods and training data were investigated. The separation into T1- and T2*-dependent signal contributions was achieved by fitting a standard analytical model to the acquired multi-echo data. The application of SMS yielded sufficient temporal resolution for the detection of the arterial input function in major vessels, while anatomical coverage allowed perfusion analysis of muscle tissue. The separation of the MR signal into T1- and T2*-dependent components allowed the correction of susceptibility related changes. We demonstrate a novel sequence for dynamic contrast-enhanced MRI that meets the requirements of temporal resolution (Δt < 1.5 s) and image quality. The incorporation of SMS into multi-contrast, segmented EPI can overcome existing limitations of dynamic contrast enhancement and dynamic susceptibility contrast methods, when applied separately. The new approach allows both techniques to be combined in a single acquisition with a large spatial coverage