检索结果-南通市图书馆

CSEE Journal of Power and Energy Systems 2019年第2期5卷 171-180页

作者： Panagiotis n.Papadopoulos Jovica v.Milanovic School of Electrical and Electronic Engineering The University of ManchesterManchesterM601QDU.K.

A methodology for online and offline dynamic stabil-ity assessment,suitable for power systems with high penetration of power electronics interface units is presented in this *** increasing penetration of renewable energy resources as well as changing market operations,new types of loads and storage technologies,are causing significant changes to power systems dynamic *** generator groups and generators exhibiting poorly damped oscillatory behavior are identified online,opening the possibility to corrective control actions in order to stabilize the ***,statistical analysis of the abundant data from simulations provides information on the overall impact of power electronics interface units on system stability.

关键词： Decision trees dynamicsecurityassessment probabilistictransientstability

Temporal and spatial variation in the sediment volume along the beaches between Ovari and Kanyakumari(SE InDIA)

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 Sediment Research 2013年第3期28卷 384-395页

作者： S.SARAvAnAn n.CHAnDRASEKAR v.JOEvIvEK Centre for GeoTechnology Manonmaniam Sundaranar University Civil Engineering Department Christ the King Engineering College

A 2-year set of profile data from Ovari to Kanyakumari Beach,SE India has been analysed by using empirical orthogonal function(EOF) techniques to identify characteristic patterns of temporal and spatial variation in the sediment volume of the *** results show that variation in the sediment volume of the beach is determined by interaction between the biennial and seasonal *** analysis the pattern of alongshore sediment exchange along the study *** method facilitated separation of onshore-offshore and alongshore modes of sediment transfer and identification of the patterns of alongshore sediment *** eigenfunction modes confirm the dominance of biennial,annual,and biannual sediment transfers occurring on study *** sediment movement along the shoreline of study area is mainly governed by the forces associated with the incoming waves and the availability of sediments within the *** present investigation has been made as an attempt to appreciate the sediment movement in relation to wave activity along the *** longshore sediment transport is intensive in the northerly direction as compared to southerly *** normal condition is for and to be moved annually or more frequently in the shallows and on the *** and wave-driven currents cause longshore drift of sand along the beach and offshore.

关键词： Beach Profile Sediment movement Beach volume change India

Electronic and optical properties of TiO_2 and its polymorphs by Z-scan method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第8期23卷 340-344页

作者： S. Divya v P n nampoori P Radhakrishnan A Mujeeb International School of Photonics Cochin University of Science and Technology

TiO2 is a material which has attracted considerable attention from the scientific community for its innumerable prop- erties. TiO2 is known to exist in nature in three different crystalline structures： rutile, anatase, and brookite. Anatase and rutile TiO2 films have been widely characterized for their potential applications in solar cells, self-cleaning coatings, and photocatalysis. In the present report, the third-order nonlinear susceptibilities of TiO2 and its polymorphs, anatase, and rutile, prepared by the sol-gel technique followed by heat treatment are investigated using the Z-scan technique at a wavelength of 532 nm with a duration of 7 ns. Imaginary and real values of Z（3） for amorphous, anatase, and rutile are also calculated and found to be 5 × 10^-19 m2/v2, 27 × 10^-19 m2/v2, 19 × 10^-19 m2/v2, respectively. It is found that the values of the optical constants of amorphous TiO2 after heat treatment vary considerably. It is assumed that this could be due to the variation in the electronic structure of TiO2 synchronous with the formation of its polymorphs, anatase, and rutile. Amorphous TiO2 is marked by the localization of the tail states near the band gap, whereas its crystalline counterparts are characterized by completely delocalized tail states.

关键词： excitons reverse saturable absorption (RSA) excitonic nonlinearity

DIFFEREnTIAL-ALGEBRAIC APPROACH TO COUPLED PROBLEMS OF DYnAMIC THERMOELASTICITY

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2006年第9期27卷 1185-1196页

作者： WAnG Lin-xiang Roderick v. n. Melnik MCI Faculty of Science and Engineering University of Southern Denmark Sonderborg DK-6400 Denmark Center for Coupled Dynamics ＆ Complex Systems Wilfrid Laurier University 75 University Avenue West Waterloo ON Canada N2L3C5

An efficient numerical approach for the general thermomechanical problems was developed and it was tested for a two-dimensional thermoelasticity problem. The main idea of our numerical method is based on the reduction procedure of the original system of PDEs describing coupled thermomechanical behavior to a system of Differential Algebraic Equations （DAEs） where the stress-strain relationships are treated as algebraic equations. The resulting system of DAEs was then solved with a Backward Differentiation Formula （BDF） using a fully implicit algorithm. The described procedure was explained in detail, and its effectiveness was demonstrated on the solution of a transient uncoupled thermoelastic problem, for which an analytical solution is known, as well as on a fully coupled problem in the two-dimensional case.

关键词： thermoelasticity two-dimensional differential-algebraic solvers

Invariant and energy analysis of an axially retracting beam

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2016年第4期29卷 952-961页

作者： Yang Xiaodong Liu Ming Zhang Wei Roderick v.n.Melnik Beijing Key Laboratory of nonlinear vibrations and Strength of Mechanical Engineering College of Mechanical Engineering Beijing University of Technology M2neT Laboratory The MS2Discovery Interdisciplinary Research Institute Wilfrid Laurier University

The mechanism of a retracting cantilevered beam has been investigated by the invariant and energy-based analysis. The time-varying parameter partial differential equation governing the transverse vibrations of a beam with retracting motion is derived based on the momentum theorem. The assumed-mode method is used to truncate the governing partial differential equation into a set of ordinary differential equations (ODEs) with time-dependent coefficients. It is found that if the order of truncation is not less than the order of the initial conditions, the assumed-mode method can yield accurate results. The energy transfers among assumed modes are discussed during retraction. The total energy varying with time has been investigated by numerical and analytical methods, and the results have good agreement with each other. For the transverse vibrations of the axially retracting beam, the adiabatic invariant is derived by both the averaging method and the Bessel function method. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-nC-nD license.

关键词： Adiabatic invariants Asymptotic analysis Retracting beam Time-varying systems Transient dynamics

Laser speckle contrast imaging for monitoring of acutepancreatitis at ischemia-reperfusion injury of thepancreas in rats

在线全文

学校读者我要写书评

暂无评论

Journal of Innovative Optical Health Sciences 2022年第1期15卷 90-102页

作者： P.A.Dyachenko(Timoshina) A.n.Bashkatov D.A.Alexandrov v.I.Kochubey v.v.Tuchin Saratov State University SaratovRussia Laboratories of Biophotonics and Laser Molecular Imaging and Machine Learning national Research Tomsk State University TomskRussia Saratov State Medical University SaratovRussia Institute of Precision Mechanics and Control Russian Academy of SciencesRussia A.n.Bach Institute of Biochemistry Research Center of Biotechnology of the Russian Academy of Sciences MoscowRussia

The influence of ischemia-reperfusion(I/R)action on pancreatic blood flow(PBF)and the development of acute pancreatitis(AP)in laboratory rats is evaluated in vivo by using the laser speckle contrast imaging(LSCI).Additionally,the optical properties in norm and under condition of AP in rats were assessed using a modied integrating sphere spectrometer and inverse Monte Carlo(IMC)*** results of the experimental study of microcirculation of the pancreas in 82 rats in the ischemic model are *** data obtained conrm the fact that local ischemia and changes in the blood°ow velocity of the main vessels cause and provoke acute pancreatitis.

关键词： Laser speckles contrast of speckle images adaptive algorithm microcirculation blood flow acute pancreatitis pancreas rats optical properties integrating sphere spectroscopy

Photocatalytic activity of Eu^(3+)-doped ZnO nanorods synthesized via microwave assisted technique

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 Rare Earths 2014年第4期32卷 306-313页

作者： P.v.Korake A.n.Kadam K.M.Garadkar nanomaterials Research Laboratory Department of Chemistry Shivaji University

The doped ZnO nanorods as a photocatalyst with different Eu contents were prepared by microwave assisted method and they were characterized by means of X-ray diffraction （XRD）, energy-dispersive X-ray spectroscopy （EDS）, Uv-vis spectroscopy, surface area Brunauer-Emmett-Teller （BET）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The average crystallite size and band gap energy of Eu-doped ZnO were varied with the Eu content. The XRD pattern of Eu-doped ZnO indicated hexagonal crystal structure with an average crystallite size of 25 nm. The pres-ence of europium with trivalent state and its doping successfully into the crystal lattice of ZnO matrix were confirmed by XPS tech-nique. The photocatalytic activity of Eu-doped ZnO nanorods was evaluated for methyl orange degradation. The photocatalytic experi-ments showed^91%degradation of methyl orange over 0.2 mol.%Eu doped ZnO sample within 3 h under Uv light （365 nm）.

关键词： zinc oxide rare earths europium nanorods microwave dye degradation

Thermophysical properties of iridium at finite temperature

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第11期25卷 404-411页

作者： Priyank Kumar n K Bhatt P R vyas v B Gohel Department of Science Government PolytechnicGandhinagar Department of Physics Sardar Patel University Department of Physics School of Science Gujarat University

The bulk properties of materials in an extreme environment such as high temperature and high pressure can be understood by studying anharmonic effects due to the vibration of lattice ions and thermally excited *** this spirit,in the present paper,anharmonic effects are studied by using the recently proposed mean-field potential（MFP） approach and Mermin functional which arise due to the vibration of lattice ions and thermally excited electrons,*** MFP experienced by a wanderer atom in the presence of surrounding atoms is constructed in terms of cold energy using the local form of the *** have calculated the temperature variation of several thermophysical properties in an extreme environment up to melting *** results of our calculations are in excellent agreement with the experimental findings as well as the theoretical results obtained by using first principle *** conclude that presently used conjunction scheme（MFP＋pseudo potential） is simple computationally,transparent physically,and accurate in the sense that the results generated are comparable and sometimes better than the results obtained by first principle *** pseudopotential used is transferable to extreme environment without adjusting its parameters.

关键词： extreme experienced melting presently excited thermally sometimes understood comparable conclude

An approach to determination of shunt circuits parameters for damping vibrations

在线全文

学校读者我要写书评

暂无评论

International Journal of Smart and nano Materials 2018年第2期9卷 135-149,I0005页

作者： v.P.Matveenko n.A.Iurlova D.A.Oshmarin n.v.Sevodina M.A.Iurlov Department of complex problems of deformable solids mechanics Institute of Continuous Media Mechanics of the Ural Branch of RAS(ICMM UB RAS)PermRussian Federation

This paper considers the problem of natural vibrations of a deformable structure containing elements made of *** piezoelectric elements are connected through electrodes to an external electric circuit,which consists of resistive,inductive and capacitive *** on the solution of this problem,the parameters of external electric circuits are searched for to allow optimal passive control of the structural *** solution to the problem is complex natural vibration frequencies,the real part of which corresponds to the circular eigenfrequency of vibrations and the imaginary part corresponds to its damping rate(damping ratio).The analysis of behaviour of the imaginary parts of complex eigenfrequencies in the space of external circuit parameters allows one to damp given modes of structure *** effectiveness of the proposed approach is demonstrated using a cantilever-clamped plate and a shell structure in the form of a semi-cylinder connected to series resonant RL circuits.

关键词： Electoelasticity piezoelectric element shunt circuits damping natural vibrations numerical modeling

BRICS and International Collaborations in Higher Education in India

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 Education in China 2015年第1期10卷 46-65页

作者： n.v.vARGHESE Centre for Policy Research in Higher Education(CPRHE) National University of Educational Planning and AdministrationNew Delhi 110019India

International cooperation and collaborations played an important role in the economic and educational development of several *** the 1950s and 1960s external aid was an important modality to establish cooperation between countries,especially between developing and developed ***-border activities in higher education used to take place mostly through cooperation projects and academic exchange *** political returns to aid declined during the post-cold war ***,incentives to extend aid declined and markets and trade became more accepted modes of cooperation and collaboration in all sectors including *** collaborations of today are very often motivated by economic incentives and are mediated through *** franchising and twinning arrangements,establishment of branch campuses,and promotion of cross-border student mobility are examples of market-based collaborative efforts in higher *** paper discusses Indian cooperation and collaborations with foreign institutions focusing also on such efforts among the BRICS *** argues that the collaboration efforts among the BRICS countries may be more influenced by government-to-government efforts than mediated by *** paper shows that the BRICS countries at present are more engaged in cooperation and collaborations in higher education with developed *** among the BRICS countries are rather limited and are still at the nascent ***,government initiatives and public action are needed at this stage to promote cooperation and expand collaboration in higher education among BRICS countries.

关键词： international cooperation collaboration franchising twinning massification university ranking