检索结果-南通市图书馆

Evidence of Correlation between High Frequency Geomagnetic Variations and Seismicity in the Caribbean

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Earthquake Research 2021年第2期10卷 30-41页

作者： Bladimir moreno eric Calais Centro Nacional de Investigaciones Sismológicas CENAIS Santiago de Cuba Cuba Ecole Normale Superieure Department of Geoscience Paris France

An analysis between the hourly distribution of earthquakes in three areas of the Caribbean and the high-frequency variations of the geomagnetic field is presented. The number of earthquakes selected for each zone is between 10,000 and 43,000, which guarantees a statistically significant distribution. The hourly distributions of seismicity in all areas show a bay-shape distribution with a significant increase in the number of earthquakes at night, from 11 PM to 5 AM. For example, in eastern Cuba 36.7% of earthquakes occur at that time, representing 11.7% over 25% in the absence of any time preference. Geomagnetic disturbances were compiled from several years to be able to make a statistically significant hourly distribution of their occurrence, being determined by sudden changes in the magnetic field at a short period of 1 minute. In this sense, geomagnetic data were processed between the years 2011-2016, recorded by the geostationary satellite GOES13 and the magnetic ground station SJG in San Juan, Puerto Rico. The result shows a significant correlation between hourly earthquakes distribution and high-frequency geomagnetic variations. The time-varying conductivity response of Earth’s interior also correlates with seismicity. The theory behind this correlation could be related to the piezoelectric phenomena and the electromagnetic force induced when the magnetic field is disturbed.

关键词： Caribbean Seismicity Conductivity Response Geomagnetic Storms Hourly Earthquakes Frequency Electromagnetic Induction Eddy Currents Geomagnetic Field

Microstructural Development and Mechanical Properties of PM Ti-45Al-2Nb-2Mn-0.8 vol.%TiB_2 Processed by Field Assisted Hot Pressing

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 Materials Science & Technology 2014年第11期30卷 1145-1154页

作者： R.Muoz-moreno E.M.Ruiz-Navas B.Srinivasarao J.M.Torralba Department of Materials Science and Engineering Universidad Carlos Ⅲ de MadridAvda.Universidad 3028911 LeganésMadridSpain IMDEA Materials Institute C/Eric Kandel 228906 GetafeMadridSpain

A γ-TiAI intermetallic alloy, Ti-45Al-2Nb-2Mn （at.%）-0.8 vol.%TiB2, has been processed from gas atomized praalloyed powder by field assisted hot pressing （FAHP）. An initial analysis of the prealloyed powder helped on the understanding of the intermetallic sintering behavior. Atomized powder consisted of α metastable phase that transformed into α2＋γ equilibrium phases by thermal treating. Different powder particle microstructures were found, which influence the microstructure development of the FAHP T-TiAI material depending on the sintering temperature. Duplex, nearly lamellar and fully lamellar microstructures were obtained at the sintaring temperatures above 1000 ℃. Lower consolidation temperatures, below 1000 ℃, led to the formation of an AI rich phase at powder particle boundaries, which is deleterious to the mechanical properties. High compressive yield strength of 1050 MPa was observed in samples with FAHP duplex microstructures at room temperature. Whereas nearly lamellar and fully lamellar microstructures showed yield strength values of 655 and 626 MPa at room temperature and 440 and 425 MPa at 750 ℃, respectively, which are superior in comparison to similar alloys processed by other techniques. These excellent properties can be explained due to the different volume fractions of the α2 and γ phases and the refinement of the PM microstructures.

关键词： Titanium aluminides Powder metallurgy Microstructure Mechanical properties Field assisted sintering

Morphological Characterization in Wild Species of Heliconias(Heliconia spp)in Mexico

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2017年第6期8卷 1210-1223页

作者： Carlos Hugo Avendano-Arrazate Jorge Alberto Arrazate-Argueta Simitrio Ortíz-Curiel Esaú moreno-Pérez Leobardo Iracheta-Donjuan Delfino Reyes-López Manuel Grajales-Solís misael Martínez-Bola?os Moises Cortés-Cruz National Forestry Crops and Livestock Research Institute(INIFAP)-Experimental Station Rosario IzapaTuxtla ChicoMexico Postgraduate College Postgraduate in EdafologyMontecilloMexico Autonomus University of Chapingo Departament of FitotecniaChapingoMexico Autonomus University of Puebla TeziutlanMexico National Genetic Resources Center–INIFAP TepatitlanMexico

In Mexico, the utilization of native heliconias germplasm for preservation and genetic improvement purposes, has been limited partly because of the unawareness between their population similarities and differences, and because of the degree of genetic divergence that exists among the interspecific and intraspecific ecotypes originated from different regions of the humid tropics. The objective of the present study was to morphological characterization wild species of the genus Heliconias in Mexico through some qualitative and quantitative morphological descriptors. Fifty-five qualitative and quantitative morphological characters were studied in 25 accessions from 11 native species. Characters of plant, leaf, inflorescence, flower, fruit, and seed were taken into account. Data was analyzed by Principal Component Analysis (PCA) and Hierarchical Cluster Analysis. Two analyses were carried out: the first one was for the 25 accessions that included characters of flower (55 variables), whereas the second was for only 19 accessions (66 variables) concluded until seed. The first six components explained a 69.4% of the total variation based on PCA. The variables which contributed most significantly were: leaf length (p < 0.001), limb width (p < 0.001), limb's petiole length (p < 0.001), pseudostem thickness (p < 0.05)/width at 60 cm (p < 0.05), rachis width (p < 0.05)/thickness (p < 0.001), second bract width (p < 0.001), growth (p < 0.001) and type of inflorescence (p < 0.05), petiole (p < 0.05) and peduncle length (p < 0.05), rachis color (p < 0.05), and wax in limb (p < 0.05) and in pseudostem (p < 0.05). Thirty-eight descriptors were suggested to differentiate wild species of heliconias in Mexico.

关键词： Heliconia Morphological Descriptors Principal Components

Cantharellus(Cantharellales,Basidiomycota)revisited in Europe through a multigene phylogeny

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fungal Diversity 2017年第2期83卷 263-292页

作者： Ibai Olariaga Gabriel moreno Jose Luis Manjon Isabel Salcedo Valerie Hofstetter Diego Rodrıguez Bart Buyck Department of Life Sciences(Botany) University of Alcala28805 Alcalade HenaresMadridSpain Department of Plant Biology and Ecology(Botany) University of the Basque Country(UPV/EHU)Apdo 64448080 BilbaoSpain Department of Plant Protection Agroscope ChanginsWadenswil Research StationACWRte de Duiller1260 NyonSwitzerland Kherdzmari St.Microdistrict 11.Block 58 Flat 69TemkaTbilisiGeorgia Departement Systematique et Evolution CP 39ISYEBUMR 7205 CNRS MNHN UPMC EPHEMuseum National d’Histoire Naturelle12 Rue Buffon75005 ParisFrance

Resolving species delimitation issues of European Cantharellus is crucial to correctly name chanterelles around the globe.Thirty names referring to Cantharellus s.***.have been described in Europe,some of which are used in other continents.Based on combined analyses of ITS2,LSU,RPB2 and TEF-1,merely eight species are here recognized in Europe applying the genealogical concordance phylogenetic species recognition criteria,one of which,C.roseofagetorum,is described as new.Morphological characters used in species delimitation are mapped and their variability evaluated.The colour of the hymenophore in young specimens is found to be a rather constant morphological character of taxonomic use.European species of Cantharellus are morphologically distinguished by unique combinations of characters,such as the presence of a pink pileal coating,pileus and hymenophore colour when young,and in some cases,the mean spore length and ecology.Eighteen type specimens from Europe are sequenced.Based on revised species concepts sixteen novel taxonomic synonyms are here proposed for European chanterelles:C.alborufescens(=C.henrici,C.ilicis,C.lilacinopruinatus),C.amethysteus(=C.cibarius subsp.squamulosus,C.cibarius var.umbrinus,C.rufipes),C.cibarius(=C.cibarius var.atlanticus,C.parviluteus),C.ferruginascens(=C.cibarius var.flavipes),C.friesii(=C.ignescens),C.pallens(=C.cibarius var.albidus,C.cibarius var.bicolor,C.subpruinosus),and C.romagnesianus(=C.pseudominimus,C.lourizanianus,C.romagnesianus var.parvisporus).The type of Cantharellus,C.cibarius,is epitypified.Descriptions,colour illustrations and a key to all European species are provided.

关键词： Cantharelloid clade Cantharellaceae Epitype Edible fungi Genealogical concordance Species delimitation

直接作用抗病毒治疗后的持续病毒反应在6,600余名患者中持续较长时间:吉利德持续病毒学反应登记研究结果

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

直接作用抗病毒治疗后的持续病毒反应在6,600余名患者中持续较长...