检索结果-南通市图书馆

Advanced topics on RF amplitude and phase detection for low-level RF systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2019年第10期30卷 9-20页

作者： Zhe-Qiao Geng roger Kalt Paul Scherrer Institut (PSI)

Low-level radio frequency(LLRF)systems stabilize the electromagnetic field in the RF cavities used for beam acceleration in particle ***,accurate,and precise detection of RF amplitude and phase is particularly important to achieve high field stability for pulsed accelerators of free-electron lasers(FEL).The digital LLRF systems employ analog-to-digital converters to sample the frequency down-converted RF signal and use digital demodulation algorithms to calculate the RF amplitude and *** sampling strategies and demodulation algorithms have been developed for these purposes and are introduced in this *** article focuses on advanced topics concerning RF detection,including accurate RF transient measurement,wideband RF detection,and RF detection with an asynchronous trigger,local oscillator,or *** analysis is based on the SwissFEL measurements,but the algorithms introduced are general for RF signal detection in particle accelerators.

关键词： Low-level radio frequency RF detector RF transient detection Asynchronous RF detection

The Severn Barrage and other tidal energy options:Hydrodynamic and power output modelling

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2009年第11期52卷 3413-3424页

作者： roger A. Falconer Reza Ahmadian Hydro-environmental Research Centre School of Engineering Cardiff University Cardiff UK

Details are given herein of the current main proposals for tidal energy provision from the Severn Estuary, in the UK, with particular emphasis being focused on the Severn Barrage project, as originally promoted by the Severn Tidal Power Group. In particular, emphasis has focused on assessing the potential hydro-environmental impacts and power outputs of a barrage across the estuary, with an unstructured grid, high resolution, model being developed and applied to the estuary to assess the implications of each of five shortlisted proposed schemes on the hydrodynamic, geomorphologic, flood risk and faecal indicator organism changes within the estuary. An outline is given of recent research on power refinements to the model to assess the options for power generation. The results show that the Severn Barrage has the potential to reduce the tidal currents in a highly dynamic estuary. This leads to the reduction of suspended sediment loads (particularly upstream of the barrage), an increase of light penetration within the water column and, potentially, an increase in the benthic bio-diversity and the level of aquatic life in the estuary. The results also show that the Severn Barrage will reduce markedly the risk of flooding upstream of the barrage and to a lesser extent downstream of the structure. In contrast the alternative options have far less impact on flood risk changes. In addition to the Severn Barrage some results are shown herein for a typical lagoon option, namely the Fleming Lagoon.

关键词： marine renewable energy Severn Estuary hydrodynamic processes tidal power finite volume models

Use of Microwave Radiances from Metop-C and Fengyun-3 C/D Satellites for a Northern European Limited-area Data Assimilation System

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2021年第8期38卷 1415-1428页

作者： Magnus LINDSKOG Adam DYBBROE roger RANDRIAMAMPIANINA Swedish Meteorological and Hydrological Institute Folkborgsvägen 1760361 NorrköpingSweden Norwegian Meteorological Institute Henrik Mohns Plass 10371 OsloNorway

MetCoOp is a Nordic collaboration on operational Numerical Weather Prediction based on a common limited-area km-scale ensemble system. The initial states are produced using a 3-dimensional variational data assimilation scheme utilizing a large amount of observations from conventional in-situ measurements, weather radars, global navigation satellite system, advanced scatterometer data and satellite radiances from various satellite platforms. A version of the forecasting system which is aimed for future operations has been prepared for an enhanced assimilation of microwave radiances. This enhanced data assimilation system will use radiances from the Microwave Humidity Sounder, the Advanced Microwave Sounding Unit-A and the Micro-Wave Humidity Sounder-2 instruments on-board the Metop-C and Fengyun-3 C/D polar orbiting satellites. The implementation process includes channel selection, set-up of an adaptive bias correction procedure, and careful monitoring of data usage and quality control of observations. The benefit of the additional microwave observations in terms of data coverage and impact on analyses, as derived using the degree of freedom of signal approach, is demonstrated. A positive impact on forecast quality is shown, and the effect on the precipitation for a case study is examined. Finally, the role of enhanced data assimilation techniques and adaptions towards nowcasting are discussed.

关键词： data assimilation regional numerical weather prediction microwave radiances

Science and Disaster Reduction

在线全文

学校读者我要写书评

暂无评论

International Journal of Disaster Risk Science 2010年第1期1卷 3-9页

作者： roger E.Kasperson Graduate School of Geography Clark University Worcester MA 01610 USA

A serious gap exists between science and disaster decision making, so that many scientific reports have little impact and fail to inform decision making. This article examines the complex linkages between science and disaster reduction, analyzing the barriers that prevent more effective use of science and suggesting how the gap between science and decision making may be narrowed.

关键词： disaster narrow decision

Environmental insults:critical triggers for amyotrophic lateral sclerosis

在线全文

学校读者我要写书评

暂无评论

Translational Neurodegeneration 2017年第1期6卷 147-156页

作者： Bing Yu roger Pamphlett Sydney Medical School(Central) The University of SydneyCamperdownNSW 2006Australia Department of Medical Genomics Royal Prince Alfred Hospital and NSW Health PathologyCamperdownNSW 2050Australia Discipline of Pathology Brain and Mind CentreThe University of Sydney94 Mallett StCamperdownNSW 2050Australia Department of Neuropathology Royal Prince Alfred HospitalCamperdownNSW 2050Australia

Background:Amyotrophic lateral sclerosis(ALS)is a fatal neurodegenerative disease characterised by a rapid loss of lower and upper motor *** a complex disease,the ageing process and complicated gene-environment interactions are involved in the majority of *** body:Significant advances have been made in unravelling the genetic susceptibility to ALS with massively parallel sequencing technologies,while environmental insults remain a suspected but largely unexplored source of *** studies applying the strategy of Mendelian randomisation have strengthened the link between environmental insults and ALS,but none so far has proved *** propose a new ALS model which links the current knowledge of genetic factors,ageing and environmental *** model provides a mechanism as to how ALS is initiated,with environmental insults playing a critical ***:The available evidence has suggested that inherited defect(s)could cause mitochondrial dysfunction,which would establish the primary susceptibility to *** study of the underlying mechanism may shed light on ALS *** insults are a critical trigger for ALS,particularly in the aged individuals with other toxicant susceptible *** identification of ALS triggers could lead to preventive strategies for those individuals at risk.

关键词： Amyotrophic lateral sclerosis Environmental risk factors Mendelian randomisation Mitochondrial dysfunction Trigger Initiation Spread

Making topological protein links using enzymatic reactions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第3期11卷 50-51页

作者： roger Castells-Graells Todd O.Yeates Department of Chemistry and Biochemistry University of California UCLA-DOE Institute for Genomics and Proteomics

Proteins are exceedingly complex molecules though, at their heart, they are essentially linear polymers. Pull at their ends and one obtains an extended backbone. While that is true in most cases, some natural proteins...

关键词：

Nanoparticles for targeted cancer radiotherapy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2020年第11期13卷 2887-2897页

作者： roger M.Pallares Rebecca J.Abergel Chemical Sciences Division Lawrence Berkeley National LaboratoryBerkeleyCA94720USA Department of Nuclear Engineering University of CaliforniaBerkeleyCA94720USA

Radiotherapy,where ionizing radiation is locally delivered either through an external beam or by surgically implanting radionuclide-based seeds in the tumor,is one of the gold standard treatments for *** to the non-selective nature of radiation,healthy tissue surrounding the cancerous region is usually affected by the ***,new strategies,including targeted alpha therapy,are being studied to improve the selectivity of the treatment and minimize side *** challenges,however,limit the current development of targeted radiotherapy,such as the functionalization of the therapeutic agent with targeting vectors and controlling the release of recoiling *** offer unique opportunities as drug delivery vehicles,since they are biocompatible,enhance the cellular uptake of drugs,and are easily functionalized with targeting *** this review,we examine how nanoparticles can be used for targeted radiotherapy,either as sensitizers of external beams or as delivery vehicles for therapeutic *** describe the clinical relevance of different types of nanoparticles,followed by an analysis of how these nanoconstructs can solve some of the main limitations of conventional ***,we critically discuss the current situation of nanoparticle-based radiotherapy in clinical settings and challenges that need to be overcome in the future for further development of the field.

关键词： radiotherapy targeted cancer radiotherapy nanoparticles cancer targeted alpha therapy external beam

Is it time to abandon the biological species concept? No

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2020年第8期7卷 1400-1401页

作者： roger K.Butlin Sean Stankowski Department of Animal and Plant Sciences University of Sheffield Department of Marine Sciences University of Gothenburg

The Oxford English Dictionary defines a concept as, ‘an idea of a class of objects, a general notion’. It follows from this definition that a concept cannot be rejected in the way that a hypothesis might be rejected if its predictions are inconsistent with observations. Instead, a concept must be judged by its heuristic value:does it help in making sense of the natural world?

关键词：

New Food Safety Law of China and the special issue on food safety in China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2015年第11期14卷 2136-2141页

作者： Shu Geng LIU Xu roger Beachy Journal of Integrative Agriculture Chinese Academy of Agricultural Sciences Sino-US Joint Food Safety Research Center Northwest A&F University Chinese Academy of Engineering World Food Center University of California

1. IntroductionThere have been a number of serious incidents of compro- mised food safety in China in recent years. To list a few, these include： a Salmonella outbreak, the use of horse- meat in burgers, the illegal use of phthalates as a clouding agent, the contamination of formula milk by melamine, the meat scandal of Shanghai Husi Food Company which sold reprocessed stale meat to many fast food chains includ- ing McDonald＇s, Burger King, and KFC across theworld,

关键词： New Food Safety Law of China and the special issue on food safety in China FSMA