检索结果-南通市图书馆

Microstructural Feature of As-cast A-356 Alloy Modifiers with the Addition of SrO

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 Wuhan University of Technology(Materials Science) 2014年第3期29卷 617-619页

作者： MU?IZ Rodrigo FLORES Alfredo ORTIZ Juan RODRíGUEZ Nelly MARTíNEZ fernando OROZCO Pilar LUNA Jesús Equihua Fabián garcía Adrián Faculty of Engineering Autonomous University of Coahuila Camporedondo UnitSaltillo Coahuila México CINVESTAV Saltillo Unit Department of Metal Mechanics Technological Institute of Saltillo Faculty of Engineering Autonomous University of Zacatecas FIME Autonomous University of Coahuila Unit

To explore the effect of strontium on the structure of as-cast A356 alloy, the strontium was incorporated to the alloy by metallothermic reduction of SrO where the mineral was added to the melt through the submerged powders injection technique. The evaluation of the modification of the eutectie silicon and the chemical analysis of samples were done using optical microscopy （OP） and inductively coupled plasma （ICP）, respectively, while microstructural analyses by scanning electron microscopy （SEM）, and the injection time was variable. Magnesium was added to the melt to increase the reactivity and reduce the surface tension of the molten aluminum. It was possible to increase the strontium content from 0 to 0.027% after 20 minutes treatment. This concentration was sufficient to bring about full modification structure of eutectic silicon of as cast alloy A 356 and the acceptable quality metallurgical of alloy.

关键词： modification microstmcture strontium eutectic silicon submerged powder injection

Using Cartesian Slice Plots of a Cosmological Simulation as Input of a Convolutional Neural Network

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第11期24卷 225-242页

作者： Guillermo Arreaga-garcía Departamento de Investigación en Física Universidad de Sonora.Apdo.Postal 14740C.P.83000HermosilloSonoraMexico

Using a uniform partitioning of cubic cells,we cover the total volume of aΛCDM cosmological simulation based on *** define a visualization cell as a spatial extension of the cubic cell,so that we collect all simulation particles contained in this visualization cell to create a series of Cartesian plots in which the overdensity of matter is clearly *** then use these plots as input to a convolutional neural network(CNN)based on the Keras library and TensorFlow for image *** assign a class to each plot,we approximate the Hessian of the gravitational potential in the center of the cubic *** selected cubic cell is then assigned a label of 1,2 or 3,depending on the number of positive eigenvalues obtained for the Householder reduction of the Hessian *** apply the CNN to several models,including two models with different visualization volumes,one with a cell size of type L(large)and the other with a cell type S(small).A third model combines the plots of the previous L and S cell *** far,we have mainly considered a slice parallel to the XY plane to make the *** last model is considered based on visualizations of cells that also include slices parallel to the ZX and ZY *** find that the accuracy in classification plots is acceptable,and the ability of the models to predict the class works *** results allow us to demonstrate the aim of this paper,namely that the usual Cartesian plots contain enough information to identify the observed structures of the cosmic web.

关键词： methods numerical cosmology theory (cosmology:)large scale structure of universe

Refractory hepatic encephalopathy in a patient with hypothyroidism: Another element in ammonia metabolism

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2017年第28期23卷 5246-5252页

作者： fernando Díaz-Fontenla Marta Castillo-Pradillo Arantxa Díaz-Gómez Luis Ibanez-Samaniego Pilar Gancedo Juan Adan Guzmán-de-Villoria Pilar Fernández-garcía Rafael Banares-Canizares Rita garcía-Martínez Unidad de Hepatología Servicio de Aparato DigestivoHospital General Universitario Gregorio Maranón Instituto de Investigación Sanitaria Hospital Gregorio Maranón Servicio de Aparato Digestivo Hospital Santa Bárbara Servicio de Radiodiagnóstico Hospital General Universitario Gregorio Maranón Centro de Investigación Biomédica en Red de Salud Mental Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas Facultad de Medicina Universidad San Pablo CEU

Hepatic encephalopathy(HE) remains a diagnosis of exclusion due to the lack of specific signs and symptoms. Refractory HE is an uncommon but serious condition that requires the search of hidden precipitating events(i.e.,portosystemic shunt) and alternative diagnosis. Hypothyroidism shares clinical manifestations with HE and is usually considered within the differential diagnosis of HE. Here,we describe a patient with refractory HE who presented a large portosystemic shunt and post-ablative hypothyroidism. Her cognitive impairment,hyperammonaemia,electroencephalograph alterations,impaired neuropsychological performance,and magnetic resonance imaging and spectroscopy disturbances were highly suggestive of HE,paralleled the course of hypothyroidism and normalized after thyroid hormone replacement. There was no need for intervention over the portosystemic shunt. The case findings support that hypothyroidism may precipitate HE in cirrhotic patients by inducing hyperammonaemia and/or enhancing ammonia brain toxicity. This case led us to consider hypothyroidism not only in the differential diagnosis but also as a precipitating factor of HE.

关键词： Hepatic encephalopathy Hypothyroidism Cognitive impairment Cirrhosis Portosystemic shunt Magnetic resonance spectroscopy

Estimation of Equivalent Model of Photovoltaic Array Using Unscented Kalman Filters

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 Modern Power Systems and Clean Energy 2024年第3期12卷 819-827页

作者： M.A.González-Cagigal JoséA.Rosendo-macías A.Gómez-Expósito the Department of Electrical Engineering University of SevilleSpainand A.Gómez-Expósito is also with ENGREEN Laboratory of Engineering for Energy and Environmental SustainabilitySevilleSpain

This paper proposes the use of the unscented Kalman filter to estimate the equivalent model of a photovoltaic(PV)array,using external measurements of current and voltage at the inverter *** estimated model is of interest to predict the power output of PV plants,in both planning and operation scenarios,and thus improves the efficient operation of power systems with high penetration of renewable *** proposed technique has been assessed in several simulated scenarios under different operating *** results show that accurate estimates are provided for the model parameters,even in the presence of measurement noise and abrupt variations under the external conditions.

关键词： Equivalent model parameter estimation photovoltaic energy unscented Kalman filter

Seasonal variation in native hydraulic conductivity between two deciduous oak species

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2020年第1期13卷 78-86页

作者： Dilia Mota-Gutiérrez Guadalupe Arreola-González Rafael Aguilar-Romero Horacio Paz Jeannine Cavender-Bares Ken Oyama Antonio Gonzalez-Rodriguez fernando Pineda-garcía Facultad de Biología Universidad Michoacana de San Nicolás de Hidalgo.Edificio RCiudad UniversitariaGral.Francisco J.Múgica S/N A-1Felicitas de Río58030 MoreliaMichoacánMexico Escuela Nacional de Estudios Superiores Unidad MoreliaUniversidad Nacional Autónoma de México.Antigua Carretera a Pátzcuaro 8701Ex-Hacienda de San Joséde La Huerta58190 MoreliaMichoacánMexico Instituto de Investigaciones en Ecosistemas y Sustentabilidad Campus MoreliaUniversidad Nacional Autónoma de México.Antigua Carretera a Pátzcuaro 8701Ex-Hacienda de San Joséde La Huerta58190 MoreliaMichoacánMexico Deparment of Ecology Evolution and BehaviorUniversity of MinnesotaSaint PaulMN 55108USA

Aims Mechanisms of plant drought resistance include both tolerance and *** vulnerability to embolism and turgor loss point are considered traits that confer tolerance,while leaf abscission and deciduousness characterizes the avoidance *** these mechanisms are thought to trade-off expressing a continuum among species,little is known on how variation in the timing and duration of leaf shedding in response to drought affect the relationship between xylem and leaf *** the present study,we explored the extent to which drought tolerance differs between two oak(Quercus)species that exhibit different leaf shedding ***,we predicted that *** Trel.,which loses leaves at the end of the dry season(late-deciduous)and is thus exposed to a greater risk of cavitation,would be more drought tolerant and more conservative in its water use than *** Liebm.,which loses its leaves for only a short period of time in the middle of the dry season(brevideciduous).Methods The study was conducted in central Mexico in a single population of each of the two oak species,separated from each other by a distance of 1.58 km,and by an altitudinal difference of 191 *** deserticola(late deciduous)is more frequent down slope,while ***(brevideciduous)tends to occur at higher elevations along the *** assessed seasonal differences(rainy versus dry season)in native stem hydraulic conductivity,and tested for variation in xylem vulnerability to cavitation,leaf water use and leaf turgor loss point between the two *** Findings The two oak species did not differ in traits conferring drought tolerance,including xylem vulnerability to embolism,leaf turgor loss point,or stomatal ***,both species had different performance during the dry season;the brevideciduous species had lower negative impact in the xylem function than the late-deciduous ***,seasonal changes in plant physiological performance

关键词： Quercus hydraulic conductivity embolisms leaf phenology

An ACO-RFD hybrid method to solve NP-complete problems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2013年第5期7卷 729-744页

作者： Pablo RABANAL Ismael RODRIGUEZ fernando RUBIO Dept. Sistemas Inforrnaiticos y Computacion Facultad de Informatica Universidad Complutense de Madrid Madrid 28040 Spain

In this paper we hybridize ant colony optimiza- tion （ACt） and river formation dynamics （RFD）, two related swarm intelligence methods. In ACt, ants form paths （prob- lem solutions） by following each other＇s pheromone trails and reinforcing trails at best paths until eventually a single path is followed. On the other hand, RFD is based on copy- ing how drops form rivers by eroding the ground and de- positing sediments. In a rough sense, RFD can be seen as a gradient-oriented version of ACt. Several previous experi- ments have shown that the gradient orientation of RFD makes this method solve problems in a different way as ACt. In particular, RFD typically performs deeper searches, which in turn makes it find worse solutions than ACt in the first exe- cution steps in general, though RFD solutions surpass ACt solutions after some more time passes. In this paper we try to get the best features of both worlds by hybridizing RFD and ACt. We use a kind of ant-drop hybrid and consider both pheromone trails and altitudes in the environment. We apply the hybrid method, as well as ACt and RFD, to solve two NP-hard problems where ACt and RFD fit in a different manner： the traveling salesman problem （TSP） and the prob- lem of the minimum distances tree in a variable-cost graph （MDV）. We compare the results of each method and we an- alyze the advantages of using the hybrid approach in each case.

关键词： river formation dynamics ant colony optimization heuristic algorithms NP-hard problems

Automotive Lighting Systems Based on Luminance/Intensity Grids: A Proposal Based on Real-Time Monitoring and Control for Safer Driving

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第3期66卷 2373-2383页

作者： Antonio Peña-garcía Huchang Liao Department of Civil Engineering&Research Group“Lighting Technology for Safety and Sustainability” University of GranadaGranada18071Spain Business School Sichuan UniversityChengdu610064China

The requirements for automotive lighting systems,especially the light patterns ensuring driver perception,are based on criteria related to the headlamps,rather than the light perceived by drivers and road ***,important factors such as pavement reflectance,driver age,or time of night,are largely *** factors such as presence of other vehicles,vehicle speed and weather conditions are considered by the Adaptive Driving Beam(ADB)and Adaptive Front-lighting System(AFS)respectively,though with no information regarding the visual perception of drivers and other road ***,it is simpler to simulate and measure the light emitted by the lamps than the light reflected by the pavement or emitted by other *** the current technology in cameras and light sensors,communication protocols,and control of Light Emitting Diodes(LED),combined with decision-making techniques applied to large amounts of data,can open a new era in the operation of headlamps and thus ensure the visual needs of drivers in real time and under actual road *** solution lies in an interaction road-sensor-headlamp,which is not based on the light emitted by headlamps,but rather on the light perceived by the *** study thus proposes a dual grid based on luminance and luminous intensity,which would manage the headlamps by optimizing driver perception and the safety of all road users.

关键词： Vehicle systems optical sensing LED control automotive lighting

How Africa Is Promoting Agricultural Innovations and Technologies amidst the COVID-19 Pandemic

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2020年第10期13卷 1345-1346页

作者： Angela Joseph fernando Consultant-The Alliance of Bioversity International and CIAT Km 17 Recta Cali-PalmiraApartado Aéreo 6713763537 CaliColombia

The COVID-19 pandemic has left an indelible mark on Africa's Agribusiness *** of households whose livelihoods depend on farming are facing a huge food *** mitigate these effects,the African Agricultural Technology Foundation(AATF)gathered a panel of renowned agricultural experts through an interactive webinar themed"Promotion of Agricultural Technologies and Innovations for Agri-Business Resilience in Africa in the Wake of COVID-19",the first in a series of several interactive seminars to be held virtually until the end of December *** seminars will focus on several topics specific to agricultural transformation,which revolve around smallholder farmers in Sub-Saharan Africa(SSA)and aim to help them come out of the cataclysmic effect of COVID-19 and recover their business and livelihoods.

关键词： Agricultural Africa interactive

Comparison of Laparoscopic Versus Open Gastrectomy with D2 Lymph Node Dissection for Advanced Gastric Cancer: a Meta-analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Comparison of Laparoscopic Versus Open Gastrectomy with D2 L...

作者： mac SANDRIE MARIELLA 重庆医科大学

学位级别：硕士

For many decades,D2 procedure has been accepted in Far East as the standard treatment for both early(EGC)and advanced gastric cancer(AGC).In case of AGC,the debate on the extent of nodal dissection has been open for many years in order to highlight the safety and efficacy of treatment,hence this study.A comprehensive literature research was performed in PubMed to identify studies that compared laparoscopic-assisted gastrectomy(LAG)and open gastrectomy(OG)with D2 lymph node dissection(D2-LND)for treatment of AGC for the last five *** of interest were checked and subjected to meta-analysis with RevMan 5.3 *** pooled risk ratios(RR)and weighted mean difference(WMD)with 95%confidence intervals(CI)were ***,19 studies were included in this *** had some advantages over OG,including shorter hospitalization(WMD-2.31;95%CI-4.09 to-0.53;P = 0.01),less blood loss(WMD-120.49;95%CI-174.27 to-66.71;P<0.01),faster bowel recovery(WMD-0.55;95%CI-0.86 to-0.24;P 0.01)and earlier ambulation(WMD-0.75;95%CI-1.38 to-0.11;P = 0.02).In terms of surgical and oncological safety,LG could achieve similar lymph nodes(WMD,-0.94,95%CI,-2.95 to 1.06;P＝0.36),a lower complication rate[odds ratio(OR),0.80;95%CI 0.68,0.97;P = 0.02],and overall survival(OS)and disease-free survival(DFS)comparable to *** conclusion:for AGCs,both techniques(LAG and OG)appeared comparable in short-and long-term *** time was needed to perform LAG;nonetheless,it had some advantages in achieving faster postoperative recovery over *** order to clarify this controversial issue ongoing trials and future studies are needed.

关键词： Advanced gastric cancer Laparoscopic gastrectomy Open gastrectomy D2 lymph node dissection meta-analysis