检索结果-南通市图书馆

Processing stages of Gd_2Sr(Al_(1-x)Fe_x)_2O_7 series

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2014年第1期33卷 47-53页

作者： Ekaterina Tugova victor Gusarov Laboratory of New Inorganic Materials Ioffe Physical Technical Institute of RAS Department of Physical Chemistry St. Petersburg State Institute of Technology Technical University

The continuous series of perovskite-related oxides with the general formula GdzSr（Al1-xFex）207 0 〈 x 〈 1 were prepared by conventional ceramic technology in air. The pro- cessing stages of Gd2Sr（Al1-xFex）207 0 〈 x 〈 1 phases were investigated by means of X-ray powder diffraction （XRD） and scanning electron microscopy （SEM） with the element phase analysis. The three main stages of GdeSr（All_~Fex）aO7 for- marion are pointed out. The analysis of the mutual influence of intermediate compounds on the synthesis of the target solid solutions of complex composition, in particular for Gd2Sr（All-xFex）207 was carried out. It is determined that the closeness of the reactive mixture composition to the composition of individual compounds Gd2SrA1207 or GdaSrFeaO7 is of importance for the realization of a partic- ular way of GdESr（Al1-xFex）207 solid solutions formation. It is shown that at x ,= 0.2 the reversing in scheme of Gd2Sr（Al1-Fex）207 series formation is observed. The formation of the Gd2Sr（Al1-xFex）207 continuous series is indicated by the monotonic dependence of molar unit cell volume on the iron content x.

关键词： Rare-earth metals Oxide materials Solid-state reactions Ceramics X-ray diffraction (XRD) Scanning electron microscopy (SEM)

Finite Element Analysis of Residual Stress and Distortion in an Eccentric Ring Induced by Quenching

在线全文

学校读者我要写书评

暂无评论

材料热处理学报 2004年第5B期25卷 746-751页

作者： LI M. victor Portland State University PO Box 751-ME Portland OR 97207-075J USA

The residual stresses and distortion induced by quenching in an eccentric ring were investigated in this study with finite element method. The ring was made of AISI 52100 steel. A fully coupled 3D temperature-displacement analysis was performed to simulate heat transfer, phase transformations, and mechanical stresses and strains during the heating and subsequent quenching processes. Commercial FEA package ABAQUS/Standard 6.4 was used for the analyses along with user subroutines developed by the authors to model the thermal and mechanical constitutive behavior. The simulation results show that transformation plasticity plays an important role on the residual stress distribution.

关键词：残余应力有限元分析变形偏心环相变塑性

Increasing effect of metamorphism on rock properties

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2015年第2期25卷 205-211页

作者： Akinbinu victor Abioye Department of Mining Engineering Federal University of Technology

This work studied the effect of increasing degree of metamorphism on the properties of *** properties investigated are the physical,mechanical and dynamic *** are important inputs in the design of many mining and civil engineering techniques such as in tunnelling,slope stability and dynamic activities associated with seismicity and *** work compared the degree of metamorphism examined through petrographic studies of the Transvaal Sequence in South Africa with the properties of the *** study shows that as the effect metamorphism increases,the state of stress,compaction of grains,cementation and the brittleness of the rocks *** addition,increase in the metamorphic effect increases the value of the rock *** degree of metamorphism of an outcrop is the key factor influencing its property *** the metamorphism effect of an outcrop may act as a guide to its engineering properties.

关键词： Geology of rock Rock property Brittleness Fragmentation and metamorphism

Investigation of electrophysical, photo- and gas-sensitive properties of ZnO–SnO_(2) sol–gel fflms

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Dielectrics 2024年第1期14卷 42-50页

作者： Irina A.Gulyaeva Alexandra P.Ivanisheva Maria G.Volkova victoria Yu.Storozhenko Soslan A.Khubezhov Ekaterina M.Bayan victor V.Petrov Research and Education Centre“Microsystem Technics and Multisensory Monitoring Systems”Southern Federal University Russia Department of Chemistry Southern Federal UniversityRussia Department of Physics North-Ossetian State University362025 VladikavkazRussia Department of Physics and Engineering ITMO University191002 PetersburgRussia

Thin nanocomposite fflms based on tin dioxide with a low content of zinc oxide(0.5–5 mol.%)were obtained by the sol–gel *** synthesized fflms are 300–600 nm thick and contains pore sizes of 19–29 *** resulting ZnO–SnO_(2) fflms were comprehensively studied by atomic force and Kelvin probe force microscopy,X-ray diffraction,scanning electron microscopy,and high-resolution X-ray photoelectron spectroscopy *** photoconductivity parameters on exposure to light with a wavelength of 470 nm were also *** study of the photosensitivity kinetics of ZnO–SnO_(2) fflms showed that the fflm with the Zn:Sn ratio equal to 0.5:99.5 has the minimum value of the charge carrier generation time *** of the activation energy of the conductivity,potential barrier,and surface potential of ZnO–SnO_(2) fflms showed that these parameters have maxima at ZnO concentrations of 0.5 mol.%and 1 mol.%.Films with 1 mol.%ZnO exhibit high response values when exposed to 5–50 ppm of nitrogen dioxide at operating temperatures of 200℃ and 250℃.

关键词： Sol–gel method,ZnO–SnO_(2) films gas-sensitive properties surface potential potential barrier conduction activation energy

Multi-temperature modeling of femtosecond laser pulse on metallic nanoparticles accounting for the temperature dependences of the parameters

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

Nanotechnology and Precision Engineering 2022年第4期5卷 26-45页

作者： victor K.Pustovalov Belarussian National Technical University Pr.Independency65Minsk 220013Belarus

This review considers the fundamental dynamical processes of metal nanoparticles during and after the impact of a femtosecond laser pulse on a nanoparticle,including the absorption of *** the sequence of events after photon absorption and their timescales is important for many applications of *** processes are discussed,starting with optical absorption by electrons,proceeding through the relaxation of the electrons due to electron–electron scattering and electron–phonon coupling,and ending with the dissipation of the nanoparticle energy into the *** goal is to consider the timescales,values,and temperature dependences of the electron heat capacity and the electron–phonon coupling parameter that describe these processes and how these dependences affect the electron energy ***-and four-temperature models for describing electron–phonon relaxation are *** emphasis is paid to the proposed analytical approach to modeling processes during the action of a femtosecond laser pulse on a metal *** consider the temperature dependences of the electron heat capacity and the electron–phonon coupling factor of the *** entire process is divided into four stages:(1)the heating of the electron system by a pulse,(2)electron thermalization,(3)electron–phonon energy exchange and the equalization of the temperature of the electrons with the lattice,and(4)cooling of the *** is an appropriate analytical description of each *** four-temperature model can estimate the parameters of the laser and nanoparticles needed for applications of femtosecond laser pulses and nanoparticles.

关键词： Femtosecond pulse Nanoparticle Metallic Model Thermal processes Analytical solution

ESTIMATION AND UNCERTAINTY QUANTIFICATION FOR PIECEWISE SMOOTH SIGNAL RECOVERY

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2023年第2期41卷 246-262页

作者： victor Churchill Anne Gelb Department of Mathematics The Ohio State UniversityColumbusOHUSA Department of Mathematics Dartmouth CollegeHanoverNHUSA

This paper presents an application of the sparse Bayesian learning(SBL)algorithm to linear inverse problems with a high order total variation(HOTV)sparsity *** the problem of sparse signal recovery,SBL often produces more accurate estimates than maximum a posteriori estimates,including those that useℓ1 ***,rather than a single signal estimate,SBL yields a full posterior density estimate which can be used for uncertainty ***,SBL is only immediately applicable to problems having a direct sparsity prior,or to those that can be formed via *** paper demonstrates how a problem with an HOTV sparsity prior can be formulated via synthesis,and then utilizes *** expands the class of problems available to Bayesian learning to include,e.g.,inverse problems dealing with the recovery of piecewise smooth functions or signals from *** examples are provided to demonstrate how this new technique is effectively employed.

关键词： High order total variation regularization Sparse Bayesian learning Analysis and synthesis Piecewise smooth function recovery

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

Temporal aiming

Light(Science & Applications) 2020年第1期9卷 741-752页

作者： victor Pacheco-Pena Nader Engheta School of Mathematics Statistics and PhysicsNewcastle UniversityNewcastle Upon Tyne NE17RUUK Department of Electrical and Systems Engineering University of PennsylvaniaPhiladelphiaPA 19104USA

Deflecting and changing the direction of propagation of electromagnetic waves are needed in multiple applications,such as in lens-antenna systems,point-to-point communications and *** this realm,metamaterials have been demonstrated to be great candidates for controlling wave propagation and wave-matter interactions by offering manipulation of their electromagnetic properties at *** have been studied mainly in the frequency domain,but their temporal manipulation has become a topic of great interest during the past few years in the design of spatiotemporally modulated artificial *** this work,we propose an idea for changing the direction of the energy propagation of electromagnetic waves by using time-dependent metamaterials,the permittivity of which is rapidly changed from isotropic to anisotropic values,an approach that we call temporal *** so doing,here,we show how the direction of the Poynting vector becomes different from that of the *** scenarios are analytically and numerically evaluated,such as plane waves under oblique incidence and Gaussian beams,demonstrating how proper engineering of the isotropic-anisotropic temporal function of ε_(r)(t)can lead to a redirection of waves to different spatial locations in real time.

关键词： anisotropic wave oblique

Opportunities and challenges in CO_(2) utilization

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 Environmental Sciences 2022年第3期34卷 322-344页

作者： Sriram Valluri victor Claremboux Surendra Kawatra Department of Chemical Engineering Michigan Technological UniversityHoughtonMI 49931USA

CO_(2) utilizations are essential to curbing the greenhouse gas effect and managing the environmental pollutant in an energy-efficient and economically-sound *** paper seeks to critically analyze these technologies in the context of each other and highlight the most important utilization avenues available thus *** review will introduce and analyze each major pathway,and discuss the overall applicability,potential extent,and major limitations of each of these pathways to utilizing CO_(2).This will include the analysis of some previously underreported utilization avenues,including CO_(2) utilization in industrial filtration and the processing of raw industrial materials such as iron and *** core theme of this paper is to seek to treat CO_(2) as a commodity instead of a liability.

关键词： CO_(2)utilization Clean energy Supercritical CO_(2) Electrochemical reduction

FORGING ASIA′S GLOBAL TRANSPARK IN THE PEARL RIVER DELTA AT ZHUHAI

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2003年第4期13卷 300-309页

作者： victor F S SIT .

The main purpose of the paper is to introduce the concept of the Global TransPark (GTP). It is a critical time to develop air logistics infrastructure in the New Economy. The paper also presents a brief review of the air cargo industry in the Asian-Pacific region and China,in particular China’s development in the industry as its economy has grown rapidly and globalized in the past two decades. The paper argues that China needs to develop a GTP to support its future growth,and explains why the Pearl River Delta-Hong Kong-Macao city-region or Extended Metropolitan Region (EMR) is the best location. Finally,it proposes that Zhuhai Airport,one of the five airports in the EMR,is the best site for the GTP. New policies from Chinese government as well as close cooperation between local governments of Guangdong and the two Special Administrative Regions of Hong Kong and Macao will be needed to make the establishment of the GTP possible.

关键词： Global TransPark airport air cargo transport Hong Kong Extended Metropolitan Region the Pearl River Delta New Economy