检索结果-南通市图书馆

Complementary examinations other than neuroimaging and neurosonology in acute stroke

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2017年第6期5卷 191-202页

作者： Adrià Arboix víctor Obach Maria José Sánchez Joan Massons Cerebrovascular Division Department of Neurology Hospital Universitari del Sagrat Cor University of Barcelona Acute Stroke Unit Department of Neurology Hospital Clínic University of Barcelona

The etiologic diagnosis of cerebrovascular diseases requires non-routine complementary examinations to be performed. Thus, in specific cases, after neuroimaging(computed tomography/magnetic resonance imaging cerebral scan sequences) and neurosonology(Doppler test of the supra-aortic trunks, transcranial echography and echocardiography), which academically allow us to classify the patients according to their etiologic stroke subtype, further examinations must be used to make a correct etiologic diagnostic. The present review aims to update knowledge about the usefulness of the different tests of blood and urine, plain chest radiography, X-ray of the spine, skull and abdomen, lumbar puncture, electroencephalography, evoked potentials, polysomnography, and pathologic examination after biopsy of the artery, skin, muscles, nerves, meninges, and brain, in the management of patients who have suffered an acute stroke.

关键词： Complementary examinations Cerebrovascular disorders Acute stroke Diagnostic techniques Blood biochemistry Polysomnography

Effect of initial microstructure on austenite formation kinetics in high-strength experimental microalloyed steels

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

International Journal of Minerals,Metallurgy and Materials 2015年第12期22卷 1304-1312页

作者： Edgar López-Martínez Octavio vázquez-Gómez Héctor Javier vergara-Hernández Bernardo Campillo Faculty of Chemistry Metallurgical Engineering Department Autonomous National University of Mexico National Council for Science and Technology Metallurgy Science Postgraduate Programme Morelia Institute of Technology Institute of Physical Sciences Autonomous National University of Mexico

Austenite formation kinetics in two high-strength experimental microalloyed steels with different initial microstructures comprising bainite-martensite and ferrite-martensite/austenite microconstituents was studied during continuous heating by dilatometric analysis. Austenite formation occurred in two steps：（1） carbide dissolution and precipitation and （2） transformation of residual ferrite to austenite. Dilatometric analysis was used to determine the critical temperatures of austenite formation and continuous heating transformation diagrams for heating rates ranging from 0.03°C.s^-1 to 0.67°C.s^-1. The austenite volume fraction was fitted using the Johnson-Mehl-Avrami-Kolmogorov equation to determine the kinetic parameters k and n as functions of the heating rate. Both n and k parameters increased with increasing heat- ing rate, which suggests an increase in the nucleation and growth rates of austenite. The activation energy of austenite formation was determined by the Kissinger method. Two activation energies were associated with each of the two austenite formation steps. In the first step, the austenite growth rate was controlled by carbon diffusion from carbide dissolution and precipitation; in the second step, it was controlled by the dissolution of residual ferrite to austenite.

关键词： non-isothermal kinetics microalloyed steel austenite heating dilatometry

Analysis of heterogeneous characteristics in a geothermal area with low permeability and high temperature

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2017年第5期8卷 1039-1050页

作者： Alfonso Aragón-Aguilar Georgina Izquierdo-Montalvo Siomara López-Blanco víctor Arellano-Gómez Instituto Nacional de Electricidad y Energías Limpias Reforma 113 Col.Palmira Cuernavaca Morelos CP 62490 Mexico

An analytical methodology for reservoir characterization was applied in the central and southwestern zones of Los Humeros geothermal field(LHGF). This study involves analysis of temperature, pressure,enthalpy and permeability in wells and their distribution along the area. The wells located in the central western side of the geothermal field are productive, whereas those located at the central-eastern side are non-productive. Through temperature profiles, determined at steady state in the analyzed wells, it was observed that at bottom conditions(approximately 2300 m depth), temperatures vary between 280 and360℃. The temperatures are higher at the eastern side of central zone of LHGF. A review of transient pressure tests, laboratory measurements of core samples, and correlation of circulation losses during drilling suggest that permeability of the formation is low. The enthalpy behavior in productive wells shows a tendency of increase in the steam fraction. It was found that productivity behavior has inverse relation with permeability of rock formation. Further, it is observed that an imbalance exists between exploitation and recharge. It is concluded from the results that the wells located at central-eastern area have low permeability and high temperature, which indicates possibility of heat storage.

关键词： Los Humeros geothermal field Reservoir performance Hot rock Enthalpy Permeability Recharge

Efficient Handling of Lock Hand-off in DSM Multiprocessors with Buffering Coherence Controllers

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2012年第1期27卷 75-91页

作者： Benjamín Sahelices Agustín de Dios Pablo Ibáez víctor vials-Yúfera José María Llabería Computer Science Department and HiPEAC European Network of Excellence University of Valladolid Valladolid Spain Computer Science and Systems Engineering Department I3A Research Institute and HiPEAC European Network of Excellence University of Zaragoza Zaragoza Spain Computer Architecture Department and HiPEAC European Network of Excellence Polytechnic University of Catalua Barcelona Spain

Synchronization in parallel programs is a major performance bottleneck in multiprocessor systems. Shared data is protected by locks and a lot of time is spent on the competition arising at the lock hand-off. In order to be serialized, requests to the same cache line can either be bounced （NACKed） or buffered in the coherence controller. In this paper, we focus mainly on systems whose coherence controllers buffer requests. In a lock hand-off, a burst of requests to the same line arrive at the coherence controller. During lock hand-off only the requests from the winning processor contribute to progress of the computation, since the winning processor is the only one that will advance the work. This key observation leads us to propose a hardware mechanism we call request bypassing, which allows requests from the winning processor to bypass the requests buffered in the coherence controller keeping the lock line. We present an inexpensive implementation of request bypassing that reduces the time spent on all the execution phases of a critical section （acquiring the lock, accessing shared data, and releasing the lock） and which, as a consequence, speeds up the whole parallel computation. This mechanism requires neither compiler or programmer support nor ISA or coherence protocol changes. By simulating a 32-processor system, we show that using request bypassing does not degrade but rather improves performance in three applications with low synchronization rates, while in those having a large amount of synchronization activity （the remaining four）, we see reductions in execution time and in lock stall time ranging from 14% to 39% and from 52% to 7170, respectively. We compare request bypassing with a previously proposed technique called read combining and with a system that bounces requests, observing a significantly lower execution time with the bypassing scheme. Finally, we analyze the sensitivity of our results to some key hardware and software parameters.

关键词： distributed shared memory multiprocessors synchronization buffer coherence controller request bypass

Analysis of the Supply Chain in Industrial Companies in Guayaquil,Ecuador-A Secondary Publication

在线全文

学校读者我要写书评

暂无评论

Proceedings of Business and Economic Studies 2024年第1期7卷 242-255页

作者： Génesis Belén Linzán Soledispa Betty Janeth Soledispa Canarte víctor Alfonso ChávezSoledispa Oscar Rolando Fiallos González Universidad Politécnica Salesiana GuayaquilEcuador Universidad Estatal del Sur de Manabí ManabíEcuador Universidad Católica de Santiago de Guayaquil GuayaquilEcuador

This research clearly outlines the supply chain in a process of evolution and digital transformation,where the collaboration of its members is concentrated,having technological tools to help chain *** analyze the advantages that this transformation produces in the supply chain,as well as its different processes,this study has a systemic perspective that involves precise elements for organizational development,such as the different phases of each process,operations,logistics,and *** must be borne in mind that any strategy in industrial companies grants the automation of procedures in the supply chain and determines a product in any phase of production,making the organization more sensitive to any variation in *** methodology included a bibliographic and non-experimental review that allows a descriptive and analytical study,which details the various characteristics of the fact that is being investigated,collecting information through interviews with different people who are involved with industrial *** the results obtained,it was identified that digital transformation helps reduce costs and generates greater *** conclusion,it was obtained that the digital supply chain helps in each of the phases of the processes,these are supervised by devices that help to have fast and effective information.

关键词： Digital transformation Supply chain Industries 4.0 Sustainability

A regionalized IO-model to value seasonal recreational ecosystem services in a mountain National Park in Spain

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

Journal of Mountain Science 2022年第1期19卷 211-227页

作者： víctor MARTIN BARROSO Mónica de CASTRO-PARDO Pascual FERNÁNDEZ MARTÍNEZ João C.AZEvEDO Department of Applied Economics I and history and economic institutions Faculty of Law and Social SciencesUniversidad Rey Juan CarlosCampus of VicálvaroTulipanMóstoles 28933Spain Department of Financial and Actuarial Economics and Statistics-Statistics and Operational Research Complutense University of MadridCampus of SomosaguasPozuelo de Alarcon 28223Spain Centro de Investigação de Montanha Instituto Politécnico de BragançaCampus de Santa ApolóniaBragança 5300-253Portugal

Recreational Ecosystem Services(RES)are among the most frequently evaluated ecosystem *** are seen as a major opportunity for sustainable development in areas of high ecological value resulting from the presence of emblematic species,habitats or scenery,often integrated in conservation areas,in particular in mountain areas affected by depopulation,rising environmental risks and ***,the assessment of RES has been based on Contingent valuation and Choice Experiments,methods with limitations related to their ***,Input-Output(IO)models provide a very accurate and effective way of valuation of RES with regional information regarding interindustry *** data on nature tourist expenditure may be only available annually,tourism inflows have a strong seasonal behavior,which impacts the profitability of several local economic *** this paper,we firstly constructed a novel regionalized IO-model based on Cross-Industry Location Quotients using employment data and,secondly,based on Monte Carlo simulation,we estimated nature tourist expenditure monthly using data on nature tourism *** method allowed for a more precise RES evaluation,estimating direct,indirect and induced monthly economic impacts of nature-based *** method was applied to the Ordesa and Monte Perdido(OMP)National Park in the Spanish *** estimate the average tourist expenditure,we collected and analyzed spending on commerce,hospitality and restaurants,leisure,and transport of 385 *** suggest that using a regionalized IO model leads to a considerable reduction of over-estimation of the economic impact of tourist expenditure estimated by conventional *** into consideration the direct,indirect and induced effects of tourist expenditure in 2016-2018,the total annual output effect in the OMP National Park amounted to€208.8 million,while the total income effect amounted to€86.29 ***,a total of

关键词： Input-Output Monte Carlo Simulation Location quotients Recreational Ecosystem Services Nature tourism Sustainable mountain development

Recent Advances in Synthesis and Properties of Hybrid Halide Perovskites for Photovoltaics

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2018年第4期10卷 167-200页

作者： C.C.vidyasagar Blanca M.Muoz Flores víctor M.Jimnez Prez Universidad Autónoma de Nuevo León Facultad de Ciencias Químicas Ciudad Universitaria School of Basic Sciences and Research in Chemistry Rani Channamma University

The progress made by the scientific community in emerging photovoltaic technologies over the past two decades has been outstanding. Numerous methods have been developed for the preparation of hybrid organic–inorganic perovskite solar cells. The power conversion efficiency has been up to 14% by a one-step vacuum deposition technique. A serious concern is the toxicity of the materials. In this review, several methods aimed at resolving these problems to some extent have been compiled, including eco-friendly synthesis. Further efficiency enhancements are expected following optimization, and a better fundamental understanding of the internal electron charge transfer, electron–hole diffusion to the corresponding layers, flexibility, and stability-dependent bandgaps is reported. This paper explores the green synthesis of organic–inorganic perovskites for industrialization. Concerning the above facts, a simple low-cost model called‘‘dispersed photovoltaic cells' ' is presented.

关键词： Perovskites Solar cells Organic–inorganic perovskites Synthetic routes Fluorescence

EXTRACTING BEHAvIOURAL MODELS FROM 2010FIFA WORLD CUP

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2013年第1期26卷 43-61页

作者： MENNDEZ Héctor BELLO-ORGAZ Gema CAMACHO David Department of Computer Science Universidad Autnoma de Madrid

The FIFA World Cup^(TM) is the most profitable worldwide *** FIFA publishes global statistics of this competition which provide global data about the players and teams during the *** work is focused on the extraction of behavioural patterns for both,players and teams strategies,through the automated analysis of this *** knowledge and models extracted in this work could be applied to soccer leagues or even it could be oriented to sport ***,the main contribution is related to the study on several automatic knowledge extraction techniques,such as clustering methods,and how these techniques can be used to obtain useful behavioural models from a global statistics *** information provided by the clustering algorithms shows similar properties which have been combined to define the models,making the human interpretation of these statistics ***,the most successful teams strategies have been analysed and compared.

关键词： Behavioural patterns clustering FIFA World Cup football soccer web mining.

Regulating lithium nucleation and growth by zinc modified current collectors

在线全文

学校读者我要写书评

暂无评论

Nano Research 2020年第1期13卷 45-51页

作者： Na Zhang Seung-Ho Yu Héctor D.Abruna Baker Laboratory Department of Chemistry and Chemical BiologyCornell UniversityIthacaNew York14853USA Department of Chemical and Biological Engineering Korea University145 Anam-roSeongbuk-guSeoul02841Republic of Korea

Lithium metal is commonly regarded as the“Holy Grail”anode material for high energy density rechargeable ***,the uncontrollable growth of Li dendrites has posed safety concerns and thus greatly hindered its large-scale *** we have modified the surface of a commercial anode current collector,Cu foil,with a thin layer of Zn by a facile electroplating method,in order to regulate the Li nucleation and the following growth *** of the formation of a solid solution buffer layer and Li-Zn alloy phases,the Li nucleation overpotential was dramatically reduced,realizing a uniform Li nucleation and a smooth Li plating *** a result,significantly improved long-term cycling performance with a high Coulombic efficiency was achieved by the lithiophilic Zn coated Cu foil as a current *** cells of Li-LiFePO4 and Li-S using the Li deposited on the Zn modified Cu as the anode,showed increased capacity with low voltage hysteresis and greatly enhanced cycling stability,ascribed to the uniform Li deposition and formation of a stable SEI *** work demonstrates the feasibility of employing lithiophilic modified Cu foils as Li metal current collectors for practical applications.

关键词： lithium metal anode lithium dendrite current collector zinc layer