检索结果-南通市图书馆

Tailoring the optical and magnetic properties of La-Bam hexaferrites by Ni substitution

Chinese Physics B 2022年第2期31卷 570-575页

作者： Hafiz T.Ali mRamzan m Imran Arshad nicola A.morley m.Hassan Abbas mohammad Yusuf Atta Ur Rehman Khalid mahmood Adnan Ali Nasir Amin mAjaz-un-Nabi Department of mechanical Engineering College of EngineeringTaif UniversityTaif 21944Saudi Arabia Department of Physics Government College UniversityFaisalabadPakistan Department of materials Science and Engineering University of SheffieldSir Robert Hadfield BuildingMapping St.SheffieldS13JDUK Department of Clinical Pharmacy College of PharmacyTaif UniversityTaif 21944Saudi Arabia

We investigate the impact of Ni insertion on the structural,optical,and magnetic properties of Ba_(0.8)La_(0.2)Fe_(12-x)Ni_(x)O_(19)hexaferrites(Ni substituted La-Bam hexaferrites).Samples were prepared using the conventional co-precipitation method and sintered at 1000℃for 4 hours to assist the crystallization *** analysis of the structure of the samples was carried out using an x-ray diffraction(XRD)*** m-type hexagonal structure of all the samples was confirmed using XRD *** lattice parameters a and c were found to be in the ranges of 5.8925±0.001 nm–5.8952±0.001 nm and 23.2123±0.001 nm–23.2219±0.001 nm,*** m-type hexagonal nature of the prepared samples was also indicated by the presence of corresponding FT-IR bands and Raman modes in the FT-IR and Raman spectra,*** results confirmed the successful synthesis of the samples according to the required stoichiometric ratio.A UV-vis spectrometer was used to record the absorption spectra of the prepared samples in the wavelength range of 200 nm–1100 *** optical energy bandgap of the samples was found to be in the range of 1.21 eV–3.39 *** m–H loops of the samples were measured at room temperature at an applied magnetic field range of 0 kOe–60 kOe.A high saturation magnetization of 99.92 emu/g was recorded in the sample with x=0 at a microwave operating frequency of 22.2 *** high value of saturation magnetization is due to the substitution of La3+ions at the spin-up(12k,2a,and 2b)*** Ni substitution is proven to be a potential candidate for the tuning of the optical and magnetic parameters of m-type ***,we suggest that the prepared samples are suitable for use in magneto-optic applications.

关键词： m-type hexaferrite nanostructured materials magnetic properties optical properties

来源：

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

Seasonal Rainfall Forecasts for the Yangtze River Basin of China in Summer 2019 from an Improved Climate Service

引用

Journal of meteorological Research 2020年第5期34卷 904-916页

作者： Philip E.BETT nicola mARTIN Adam A.SCAIFE Nick DUNSTONE Gill m.mARTIN nicola GOLDING Joanne CAmP Peiqun ZHANG Chris D.HEWITT Leon HERmANSON Chaofan LI Hong-Li REN Ying LIU min LIU met Office Hadley Centre Exeter EXI 3PBUK Plymouth marine Laboratory Plymouth PL13DHUK College of Engineering Mathematics and Physical SciencesUniversity of ExeterDevon EX44QFUK Laboratory for Climate Studies National Climate CenterChina Meteorological AdministrationBeijing 100081China University of Southern Queensland Toowoomba QLD 4350Australia Center for monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China Wuhan Regional Climate Center Wuhan 430074China

Rainfall forecasts for the summer monsoon season in the Yangtze River basin(YRB) allow decision-makers to plan for possible flooding, which can affect the lives and livelihoods of millions of people. A trial climate service was developed in 2016, producing a prototype seasonal forecast product for use by stakeholders in the region, based on rainfall forecasts directly from a dynamical model. Here, we describe an improved service based on a simple statistical downscaling approach. Through using dynamical forecast of an East Asian summer monsoon(EASm) index, seasonal mean rainfall for the upper and middle/lower reaches of YRB can be forecast separately by use of the statistical downscaling, with significant skills for lead times of up to at least three months. The skill in different sub-basin regions of YRB varies with the target season. The rainfall forecast skill in the middle/lower reaches of YRB is significant in may–June–July(mJJ), and the forecast skill for rainfall in the upper reaches of YRB is significant in June–July–August(JJA). The mean rainfall for the basin as a whole can be skillfully forecast in both mJJ and JJA. The forecasts issued in 2019 gave good guidance for the enhanced rainfall in the mJJ period and the near-average conditions in JJA. Initial feedback from users in the basin suggests that the improved forecasts better meet their needs and will enable more robust decision-making.

关键词： seasonal rainfall forecasts climate service Yangtze River basin(YRB) East Asian summer monsoon(EASm)

来源：

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

Radio observations of the first three-months of Fermi AGN at 4.8 GHz

引用

Research in Astronomy and Astrophysics 2012年第2期12卷 147-157页

作者： nicola marchili Thomas P.Krichbaum Lars Fuhrmann Anton Zensus max-Plank-Institut fr Radioastronomie

Using the Urumqi 25 m radio telescope, sources from the first three months of the Fermi-large area telescope detected active galactic nuclei （AGN） catalog with a declination of 〉 0° were observed in 2009 at 4.8 GHz. The radio flux density ap- peared to correlate with the γ-ray intensity. Intra-day variability （IDV） observations were performed in march, April and may 2009 for 42 selected γ-ray bright blazars, and ~60% of them showed evidence of flux variability at 4.8 GHz during the IDV observations. The IDV detection rate was higher than that in previous flat-spectrum AGN samples. IDV appeared more often in the very long baseline interferometry-core dominant blazars, and the non-IDV blazars showed relatively ＂steeper＂ spectral in- dices than the IDV blazars. Pronounced inter-month variability was also found in two BL Lac objects： J0112＋2244 and J0238＋1636.

关键词： galaxies: active - quasars: general - radio continuum: galaxies -gamma-rays: observations

来源：

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

Thermodynamics and dielectric response of BaTiO_(3)by data-driven modeling

引用

npj Computational materials 2022年第1期8卷 1998-2014页

作者： Lorenzo Gigli max Veit michele Kotiuga Giovanni Pizzi nicola marzari michele Ceriotti Laboratory of Computational Science and modeling(COSmO) Institute of MaterialsÉcole Polytechnique Fédérale de LausanneCH-1015LausanneSwitzerland Theory and Simulation of materials(THEOS)and National Centre for Computational Design and Discovery of Novel materials(mARVEL) École Polytechnique Fédérale de LausanneCH-1015LausanneSwitzerland

modeling ferroelectric materials from first principles is one of the successes of density-functional theory and the driver of much development effort,requiring an accurate description of the electronic processes and the thermodynamic equilibrium that drive the spontaneous symmetry breaking and the emergence of macroscopic *** demonstrate the development and application of an integrated machine learning model that describes on the same footing structural,energetic,and functional properties of barium titanate(BaTiO_(3)),a prototypical *** model uses ab initio calculations as a reference and achieves accurate yet inexpensive predictions of energy and polarization on time and length scales that are not accessible to direct ab initio *** predictions allow us to assess the microscopic mechanism of the ferroelectric *** presence of an order-disorder transition for the Ti off-centered states is the main driver of the ferroelectric transition,even though the coupling between symmetry breaking and cell distortions determines the presence of intermediate,partly-ordered ***,we thoroughly probe the static and dynamical behavior of BaTiO_(3)across its phase diagram without the need to introduce a coarse-grained description of the ferroelectric ***,we apply the polarization model to calculate the dielectric response properties of the material in a full ab initio manner,again reproducing the correct qualitative experimental behavior.

关键词： transition ferroelectric dielectric

来源：

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

Electric Drive for an In-wheel Fractional-slot Axial Flux machine

引用

电力电子技术 2008年第10期42卷 7-10页

作者： Luigi Alberti nicola Bianchi Department of Electrical Engineering University of Padova via Gradenigo 61A 1-35131 Padova Italy

This paper describes the electric drive for an in-wheel fractional-slot axial flux machine,designed for achieving a wide flux-weakening operating *** using a slotted stator with fractional-slot windings and additional cores enclosing end windings,the axial flux machine reaches a wide constant power speed *** machine is designed for increasing flux-weakening capability while obtaining low harmonic back-electromotive force and low cogging torque.A 10 N.m axial flux machine exhibiting 3 to 1 flux-weakening speed range has been built.A flux-weakening controller,able to maximize the output torque in the flux-weakening region,is designed and *** goodness of both design and control algorithm is proved by experimental ***,such a fractional-slot machine has not only *** losses are very high,and they have to be properly considered during the design process.

关键词：电气传动技术轴向磁机电子技术传动系统

来源：

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

Recurrence and survival following microwave, radiofrequency ablation, and hepatic resection of colorectal liver metastases: A systematic review and network meta-analysis

引用

Hepatobiliary & Pancreatic Diseases International 2021年第4期20卷 307-314页

作者： Paschalis Gavriilidis Keith J Roberts nicola de’Angelis Luca Aldrighetti Robert P Sutcliffe Department of Hepato-Pancreato-Biliary and Liver Transplant Surgery Queen Elizabeth University Hospitals Birmingham NHS Foundation TrustB152THUnited Kingdom Department of Digestive Surgery University Hospital Henri Mondor(AP-HP)94010 Créteil and University of Paris EstCréteilFrance Division of Hepatobiliary surgery San Raffaele HospitalVia Olgettina 60Milan 20132Italy

Background: Gold standard for colorectal liver metastases(CRLm) remains hepatic resection(HR). However, patients with severe comorbidities, unresectable or deep-situated resectable CRLm are candidates for ablation. The aim of the study was to compare recurrence rate and survival benefit of the microwave ablation(mWA), radiofrequency ablation(RFA) and HR by conducting the first network meta-analysis. Data sources: Systematic search of the literature was conducted in the electronic databases. Both updated traditional and network meta-analyses were conducted and the results were compared between them. Results: HR cohort demonstrated significantly less local recurrence rate and better 3-and 5-year diseasefree(DFS) and overall survival(OS) compared to mWA and RFA cohorts. HR cohort included significantly younger patients and with significantly lower preoperative carcinoembryonic antigen(CEA) by 10.28 ng/m L compared to RFA cohort. Subgroup analysis of local recurrence and OS of solitary and ≤3 cm CRLms did not demonstrate any discrepancies when compared with the whole sample. Conclusions: For resectable CRLm the treatment of choice still remains HR. mWA and RFA can be used as a single or adjunct treatment in patients with unresectable CRLm and/or prohibitive comorbidities.

关键词： microwave ablation Radiofrequency ablation Hepatic resection Liver resection

来源：

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

Screw dislocation structure and mobility in body centered cubic Fe predicted by a Gaussian Approximation Potential

引用

npj Computational materials 2018年第1期4卷 90-96页

作者： Francesco maresca Daniele Dragoni Gábor Csányi nicola marzari William A.Curtin Laboratory for multiscale mechanics modeling(LAmmm) Institute of Mechanical EngineeringÉcole Polytechnique Fédérale de LausanneLausanne CH-1015Switzerland Theory and Simulation of materials(THEOS) and National Centre for Computational Design and Discovery of Novel Materials(NCCR MARVEL)École Polytechnique Fédérale de LausanneLausanne CH-1015Switzerland Dipartimento di Scienza dei materiali Universitàdi Milano-BicoccaVia R.Cozzi 55Milan I-20125Italy Department of Engineering University of CambridgeTrumpington StreetCambridge CB21PZUK

The plastic flow behavior of bcc transition metals up to moderate temperatures is dominated by the thermally activated glide of screw dislocations,which in turn is determined by the atomic-scale screw dislocation core structure and the associated kink-pair nucleation mechanism for *** complex plasticity phenomena requires the simulation of many atoms and interacting dislocations and *** sizes are beyond the scope of first-principles methods and thus require empirical interatomic *** for the technological important case of bcc Fe,existing empirical interatomic potentials yield spurious ***,the structure and motion of the screw dislocations in Fe are studied using a new Gaussian Approximation Potential(GAP)for bcc Fe,which has been shown to reproduce the potential energy surface predicted by density-functional theory(DFT)and many associated *** Fe GAP predicts a compact,non-degenerate core structure,a single-hump Peierls potential,and glide on{110},consistent with DFT *** thermally activated motion at finite temperatures occurs by the expected kink-pair nucleation and propagation *** stress-dependent enthalpy barrier for screw motion,computed using the nudgedelastic-band method,follows closely a form predicted by standard theories with a zero-stress barrier of~1 eV,close to the experimental value of 0.84 eV,and a Peierls stress of~2 GPa consistent with DFT predictions of the Peierls potential.

关键词： structure dislocation cubic

来源：

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

Integrating Remote Sensing and GIS Techniques with Conventional methods to Assess and Characterize Surface and Groundwater Resources of Tendaho Graben, Ethiopia

引用

International Journal of Geosciences 2018年第5期9卷 272-288页

作者： Taddesse m. Bollollo nicola Perilli Surveying Geospatial and Civil Informatics Center ECDSWC Addis AbabaEthiopia Ethiopian Institute of Water Resources Addis Ababa University Addis Ababa Ethiopia Civil and Industrial Engineering Department Pisa University Pisa Italy

The study focused on water resource assessment through utilization of remote sensing, which is a powerful technique for the collection of multi-temporal synoptic data sets. Geographic Information System (GIS) has been also used for turning large volumes of spatial data into useful information by integrating spatial data such as topography, geology, precipitation, land cover, satellite images etc. for joint analysis. In this study Remote sensing techniques have offered useful information on regional geology, geomorphology, hydrology, soils and land use. Using Landsat 7 ETm+ path 167, row 52 drainage conditions, land use/cover, drainage patterns, lineaments and geomorphology (relief, morphology) analysis and interpretation have been made, all of which have influences on the movement and occurrence of groundwater. The interpretation of satellite data in conjunction with sufficient ground truth has made it possible to identify and outline various ground features that serve as direct or indirect indicators of the occurrence of groundwater. Different image processing techniques have been deployed to extract specific information for required analyses. Spatial filtering for tectonic structures identification, False Color Composite for identification of lithology, drainage etc. have been deployed. Through the spatial integration, it is observed that tectonic structures have controlled surface and sub surface water availability of the area. The present works in general have focused on the role of remote sensing and GIS techniques in surface and groundwater resources assessment with limited application of conventional methods. Remote sensing has invaluable capability in groundwater and surface water assessment of an area like this Graben where there is accessibility problem and challenging hot climatic conditions which hinders ground investigations.

关键词： Remote Sensing GIS Groundwater Afar Graben Tectonics

来源：

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

Using the *** website to obtain robust phylogenies for avian comparative studies： A primer

引用

Current Zoology 2015年第6期61卷 959-965页

作者： Diego RUBOLINI Andras LIKER Laszlo Z. GARAmSZEGI Anders P. mOLLEIR nicola SAINO Dipartimento di Bioscienze Universita degli Studi di Milano via Celoria 26 1-20133 Milano Italy Department of Limnology University of Pannonia Pf. 158 H-8201 Veszpr6m Hungary Department of Evolutionary Ecology Estaci6n Biol6gica de Dofiana-CSIC c/Americo Vespucio s/n E-41092 Seville Spain Laboratoire Ecologie Systematique et Evolution UMR 8079 CNRS Universit6 Paris-Sud XI-AgroParisTech Batiment 362 Universit6 Paris-Sud XI F-91405 Orsay Cedex France

Comparative studies of trait evolution require accounting for the shared evolutionary history. This is done by includ- ing phylogenetic hypotheses into statistical analyses of species＇ traits, for which birds often serve as excellent models. The online publication of the most complete molecular phylogeny of extant bird species （***, BirdTree hereafter） now allows evolutionary biologists to rapidly obtain sets of equally plausible phylogenetic trees for any set of species to be incorporated as a phylogenetic hypothesis in comparative analyses. We discuss methods to use BirdTree tree sets for comparative studies, either by building a consensus tree that can be incorporated into standard comparative analyses, or by using tree sets to account for the ef- fect of phylogenetie uncertainty. methods accounting for phylogenetic uncertainty should be preferred whenever possible because they should provide more reliable parameter estimates and realistic confidence intervals around them. Based on a real compara- tive dataset, we ran simulations to investigate the effect of variation in the size of the random tree sets downloaded from BirdTree on the variability of parameter estimates from a bivariate relationship between mass-specific productivity and body mass. Irre- spective of the method of analysis, using at least 1,000 trees allows obtaining parameter estimates with very small （〈 0.15%） co- efficients of variation. We argue that BirdTree, due to the ease of use and the major advantages over previous ＇traditional＇ meth- ods to obtain phylogenetic hypotheses of bird species （e.g. supertrees or manual coding of published phylogenies）, will become the standard reference in avian comparative studies for years to come.

关键词： Birds BirdTree Comparative method PGLm PGLS Phylogenetic uncertainty

来源：

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

Planktonic foraminifera as bio-indicators for monitoring the climatic changes that have occurred over the past 2000 years in the southeastern Tyrrhenian Sea

引用

Integrative Zoology 2014年第4期9卷 542-554页

作者： Fabrizio LIRER mario SPROVIERI mattia VALLEFUOCO Luciana FERRARO nicola PELOSI Laura GIORDANO Lucilla CAPOTONDI Institute for Coastal marine Environment National Research CouncilNaplesItaly Institute for Coastal marine Environment National Research CouncilTorretta Granitola(Fraz.Campobello di MazaraTp)Italy Istituto Scienze marine Istituto per l’Ambiente Marino CostieroConsiglio Nazionale delle RicercheConsiglio Nazionale delle RicercheBolognaItaly and Institute of Marine SciencesNational Research CouncilBolognaItaly

A high-resolution integrated study has been performed in a super-expanded marine record(sedimentation rate spanning from 11 cm/100 years to 20 cm/100 years)from the continental shelf area of the southeastern Tyrrhenian *** foraminiferal distribution illustrates 6 major environmental changes during the past 2000 years:(i)the Roman Period-Dark Age transition(from herbivorous-opportunistic to carnivorous species);(ii)the Dark Age-mCA transition(from carnivorous to herbivorous-opportunistic species);(iii)the medieval Classic Anomaly-Little Ice Age transition(a further and definitive change from carnivorous to herbivorous-opportunistic species);(iv)the period during the maunder event between approximately 1720 AD and 1740 AD(turnover from the carnivorous planktonic foraminifer Globigerinodes ruber to the herbivorous-opportunistic planktonic foraminifer Turborotalita quinqueloba);(v)the Industrial Period(dominance of herbivorous-opportunistic planktonic foraminifera);and(vi)the modern Warm Period at approximately 1940 AD(the last turnover in favor of herbivorous-opportunistic planktonic foraminifers,associated with an increase in benthic foraminifera).Our studies lead us to link this latter feature to an anthropogenic impact associated with the damming of Sele River(Salerno Gulf)at 1934 AD,which induced a change in the sediment input with a strong decrease in coarse-grained fraction and a probable alteration in nutrient ***δ^(18)O_(***) record of the past 2000 years shows the alternation of warm/wet and cold/dry events related to the Roman Period,the Dark Age,the medieval Classic Anomaly,the Little Ice Age,the Industrial Period and the modern Warm *** 5 evidentδ^(18)O_(***) oscillations(between approximately 1325 AD and 1940 AD)coincide with the 5 minima in the solar activity record(Wolf,Spörer,maunder,Dalton and Damon events).

关键词： mediterranean Basin oxygen stable isotopes planktonic foraminifera southeastern Tyrrhenian Sea

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：