检索结果-南通市图书馆

Multi-exponential model to describe pressure-dependent p-and s-wave velocities and its use to estimate the crack aspect ratio

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical engineering 2022年第2期14卷 385-395页

作者： Mihály Dobróka Norbert péter szabó Tünde edit Dobróka Mátyás Krisztián Baracza Department of Geophysics University of MiskolcMiskolc-Egyetemváros3515Hungary MTA-Me Geoengineering Research Group University of MiskolcMiskolc-Egyetemváros3515Hungary Research Institute of Applied earth sciences University of MiskolcMiskolc-Egyetemváros3515Hungary

We present new quantitative model describing the pressure dependence of acoustic p-and s-wave *** that a variety of individual mechanisms or defects(such as cracks,pore collapse and grain crushing)can contribute to the pressure-dependent change of the wave velocity,we order a characteristic pressure to all of them and allow a series of exponential terms in the description of the(pand s-waves)velocity-pressure *** estimate the parameters of the multi-exponential rock physical model in inversion procedures using laboratory measured p-and s-wave velocity *** is known,the conventional damped least squares method gives acceptable results only when one or two individual mechanisms are *** the number of exponential terms leads to highly nonlinear ill-posed inverse *** to this reason,we develop the spectral inversion method(sIM)in which the velocity amplitudes(the spectral lines in the characteristic pressure spectrum)are only considered as *** characteristic pressures(belonging to the velocity amplitudes)are excluded from the set of inversion unknowns,instead,they are defined in a set of fixed positions equidistantly distributed in the actual interval of the independent variable(pressure).Through this novel linear inversion method,we estimate the parameters of the multi-exponential rock physical model using laboratory measured p-and s-wave velocity *** characteristic pressures are related to the closing pressures of cracks which are described by well-known rock mechanical relationships depending on the aspect ratio of elliptical *** gives the possibility to estimate the aspect ratios in terms of the characteristic pressures.

关键词： Multi-exponential rock physical model spectral inversion method(sIM) Crack aspect ratio Characteristic pressures

Restructuring of plasmonic nanoparticle aggregates with arbitrary particle size distribution in pulsed laser fields

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 563-570页

作者： A e ershov A p Gavrilyuk s V karpov s p polyutov Institute of Computational Modeling Russian Academy of SciencesKrasnoyarsk 660036Russia L.V.Kirensky Institute of physics of the Russian Academy of sciences Krasnoyarsk 660036Russia siberian Federal University Krasnoyarsk 660028Russia siberian state Aerospace University Krasnoyarsk 660037Russia

We have studied processes of interaction of pulsed laser radia.ion with resonant groups of plasmonic nanoparticles（resonant domains） in large colloidal nanoparticle aggregates having different interparticle gaps and particle size *** processes are responsible for the origin of nonlinear optical effects and photochromic reactions in multiparticle *** describe photo-induced transformations in resonant domains and alterations in their absorption spectra remaining after the pulse action,we introduce the factor of spectral *** on calculation of changes in thermodynamic,mechanical,and optical characteristics of the domains,the histograms of the spectrum photomodification factor have been obtained for various interparticle gaps,an average particle size,and the degree of *** in spectra have been analyzed depending on the intensity of laser radia.ion and various combinations of size characteristics of *** obtained results can be used to predict manifestation of photochromic effects in composite materials containing different plasmonic nanoparticle aggregates in pulsed laser fields.

关键词： resonant arbitrary pulsed dipole manifestation alterations extinction remaining aggregate colloidal

emission colour tuning in KLnF_(4):Yb^(3+),er^(3+)/Ho^(3+)phosphor

在线全文

学校读者我要写书评

暂无评论

Journal of Rare earths 2024年第1期42卷 57-65,I0002页

作者： Janani K Gayathri e Vijayatha V Ramasubramanian s Thiyagarajan p Department of science and Humanities Nehru Institute of TechnologyKaliapuramThirumalayampalayamCoimbatoreIndia Department of sciences Amrita School of Physical SciencesAmrita Vishwa VidyapeethamCoimbatoreIndia Department of physics Anna UniversityChennaiIndia

KLnF_(4):Yb^(3+),er^(3+)/Ho^(3+)(Ln=Y,Yb,Gd)phosphors were prepared by solid-state reaction *** each of the Yb^(3+)/er^(3+)and Yb^(3+)/Ho^(3+)co-doped phosphors independently,phase confirmation and morphological examination were accomplished using the X-ray diffraction technique and scanning electron microscope analysis.X-ray photoelectron spectroscopy analysis shows the charge state and existence of lanthanides and *** luminescence emissions of green and red colour were detected for the synthesized *** changes in the upconverted emission intensities and colour output pertaining to the change of the lanthanide host matrix along with dopants were investigated for the prepared *** the upconversion luminescence,erbium-doped samples exhibit a predominance of red emission while holmium-doped samples display a prevalence of green *** rare-earth er/Ho doped KYbF4shows strong red emission compared to other ***_(4):Yb,er/Ho exhibits relatively significant green upconve rsion emissions,while Yb,er-doped KGdF_(4)host displays a 10-fold increase in green/red emission ratio with an increase in the input power of 20-780 *** photoluminescence studies and decay curve analysis were carried out using UV light excitation for the developed phosphors.A higher lifetime of 2.2 ms was measured for the downshifting red emission in the Ho doped KYbF_(4)*** study suggests a potential for colour tunability in the upconversion and downshifting emissions through host modifications to the fluoride phosphor.

关键词： Rare earths energy transfer upconversion Downshifting Colour coordinates

processes underlying the laser photochromic effect in colloidal plasmonic nanoparticle aggregates

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2020年第3期29卷 412-419页

作者： A e ershov V s Gerasimov I L Isaev A p Gavrilyuk s V karpov Institute of Computational Modeling sB RAs 660036KrasnoyarskRussia siberian Federal University Krasnoyarsk660041Russia Kirensky Institute of physics Federal Research Center KSC SB RAS660036KrasnoyarskRussia siberian state University of science and Technology Krasnoyarsk 660014Russia

We have studied the dynamic and static processes occurring in disordered multiparticle colloidal Ag aggregates with natural structure and affecting their plasmonic absorption spectra under pico-and nanosecond pulsed laser radia.ions, as well as the physical origin responsible for these processes. We have shown that depending on the duration of the laser pulse,the mechanisms of laser modification of such aggregates can be associated both with changes in the resonant properties of the particles due to their heating and melting(picosecond irradia.ion mode) and with the particle shifts in the resonant domains of the aggregates(nanosecond pulses) which depend on the wavelength, intensity, and polarization of the *** mechanisms result in formation of a narrow dip in the plasmonic absorption spectrum of the aggregates near the laser radia.ion wavelength and affect the shape and position of the dip. The effect of polydispersity of nanoparticle aggregates on laser photochromic reaction has been studied.

关键词： nanoparticle surface plasmon resonance photochromic process pulsed laser radia.ion

Theoretical investigation of micropolar fluid flow between two porous disks

在线全文

学校读者我要写书评

暂无评论

Journal of Central south University 2015年第7期22卷 2825-2832页

作者： p.Valipour s.e.Ghasemi M.Vatani Department of Textile and Apparel Qaemshahr Branch Islamic Azad University Young Researchers and elite Club Qaemshahr Branch Islamic Azad University Department oaf Mechanical engineering Babol University of Technology

The steady, laminar, incompressible and two dimensional micropolar flow between two porous disks was investigated using optimal homotopy asymptotic method(OHAM) and fourth order Runge–Kutta numerical method. Comparison between OHAM and numerical method shows that OHAM is an exact and high efficient method for solving these kinds of problems. The results are presented to study the velocity and rotation profiles for different physical parameters such as Reynolds number, vortex viscosity parameter, spin gradient viscosity and microinertia density parameter. As an important outcome, the magnitude of the microrotation increases with an increase in the values of injection velocity while it decreases by increasing the values of suction velocity.

关键词： theoretical investigation porous disks micropolar fluid flow optimal homotopy asymptotic method(OHAM) microrotation

Cellular automata modelling of grain coarsening during reheating——Ⅱ. Abnormal grain growth

在线全文

学校读者我要写书评

暂无评论

Journal of University of science and Technology Beijing 2005年第1期12卷 26-32页

作者： WanhuaYu e.J.palmiere s.p.Banks JingtaoHan DepartmentofMaterialsengineering UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofengineeringMaterials UniversityofSheffieldS13JDSheffieldUK DepartmentofAutomaticControlandsystemsengineering UniversityofSheffieldS13JDSheffieldUK

The 2-dimensional cellular automata (CA) simulation technique has been utilized to investigate the abnormal grain coarsening. The growth of abnormal grains is modelled under this assumption that different grains have different boundary energies and boundary mobilities. As temperature increases, some grains may first get rid of the particle pinning effect. Thus a high probability is obtained for atoms to jump over the boundary, so that they can consume other primary retained grains quickly. From the simulation, the characteristics of the abnormal grain coarsening under different conditions are demonstrated successfully. An experiment has also been carried out to reflect the abnormal grain coarsening on the microalloy steel. simulation results are quite close to the experimental evidence.

关键词： computer simulation grain growth microstructure reheating

Cellular automata modelling of austenite grain coarsening during reheating——I. Normal grain coarsening

在线全文

学校读者我要写书评

暂无评论

Journal of University of science and Technology Beijing 2004年第6期11卷 517-523页

作者： WanhuaYU e.J.palmiere s.p.Banks JingtaoHan Materialsscienceandengineeringschool UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofengineeringMaterials UniversityofSheffieldSheffieldS13JDUK DepartmentofAutomaticControlandsystemsengineering UniversityofSheffieldSheffieldS13JDUK

A two-dimensional cellular automaton (CA) model has been developed for thedescription of the normal grain coarsening process. The probabilistic CA method incorporatingMoore's definition of the neighbourhood is used to simulate the normal grain coarsening process witha new transition rule. The model simulates the grain coarsening process in as much detail that ispossible, from the point of initial nucleation to subsequent coarsening with computational *** unique result is that the grain coarsening speed can be controlled by the specific method, thisresult is vital to model the grain coarsening quantitatively. In order to make this model valid,experimental work has been done to provide solid evidence for this model. Comparison of themodelling result and the experimental result has been carried out.

关键词： computer simulation grain growth microstructure reheating

effect of local environment in resonant domains of polydisperse plasmonic nanoparticle aggregates on optodynamic processes in pulsed laser fields

在线全文

学校读者我要写书评

暂无评论

Chinese physics B 2015年第4期24卷 467-474页

作者： A.e.ershov A.p.Gavrilyuk s.V.karpov p.N.semina L.V.Kirensky Institute of physics Russian Academy of Sciences Institute of Computational Modeling Russian Academy of Sciences siberian state Aerospace University siberian Federal University

Interactions of pulsed laser radia.ion with resonance domains of multiparticle colloidal aggregates having an increasingly complex local environment are studied via an optodynamic model. The model is applied to the simplest configurations, such as single particles, dimers, and trimers consisting of mono- and polydisperse Ag nanoparticles. We analyze how the local environment and the associated local feld enhancement by surrounding particles affect the optodynamic processes in domains, including their photomodification and optical properties.

关键词： nanoparticle surface plasmon colloid aggregate optodynarnics

Optimized model-based control of main mine ventilation air flows with minimized energy consumption

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining science and Technology 2020年第4期30卷 533-539页

作者： s.sjostrom e.Klintenas p.Johansson J.Nyqvist Department IApI–Mining Automation ABB ABUmeå140090124Sweden

In early 2018,the Boliden Garpenberg operation implemented an optimized control strategy as an addition to the existing ventilation on demand *** purpose of the strategy is to further minimize energy use for main and booster fans,whilst also fulfilling airflow setpoints without violating constraints such as min/max differential pressure over fans and interaction of air between areas in *** air flow measurements and a dynamical model of the ventilation system,a mine-wide coordination control of fans can be carried *** numerical model is data driven and derived from historical operational data or step changes *** makes both initial deployment and lifetime model maintenance,as the mine evolves,a comparably easy *** control has been proven to operate in a stable manner over long periods without having to re-calibrate the *** prove a 40%decrease in energy use for the fans involved and a greater controllability of air ***,a 15%decrease of the total air flow into the mine will give additional proportional heating savings during winter *** in all,the multivariable controller shows a correlation between production in the mine and the ventilation system performance superior to all of its predecessors.

关键词： Mine ventilation Ventilation on demand Optimized model-based control Minimized energy consumption Advanced process control