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Creating and moving nanoantenna cold spots anywhere

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Light(Science & Applications) 2022年第10期11卷 2335-2344页

作者： Alex j.Vernon Francisco j.Rodriguez-Fortuno Department of Physics King's College LondonStrandLondon WC2R 2LSUnited Kingdom

Cold spots are sub-wavelength regions which might emerge near a nanoantenna,should one or more components of some far-field illumination cancel out with scattered *** show that by changing only the polarisation,amplitude,and phase of two plane waves,a unique,zero-magnitude and highly sub-wavelength cold spot can be created and moved anywhere in the space around a nanoantenna of any arbitrary *** can be achieved using ultra-fast modulated pulses,or a time-harmonic *** disturbed by a change in the nanoantenna's material or position,a manufactured cold spot is fragile and could be used in nanoscale *** technique exploits the linearity of Maxwell's equations and could be adapted to manipulate any phenomena governed by the linear wave equation,including acoustic *** is a means for potentially ultra-fast sub-wavelength electric field manipulation.

关键词： illumination scattered arbitrary

Thermoelastic Analysis of Non-uniform Pressurized Functionally Graded Cylinder with Variable Thickness Using First Order Shear Deformation Theory(FSDT) and Perturbation Method

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Chinese journal of Mechanical Engineering 2015年第6期28卷 1149-1156页

作者： KHOSHGOFTAR M j MIRZAALI M j RAHIMI G H Faculty of Mechanical Engineering Tarbiat Modares University Department of Mechanical Engineering Faculty of Engineering Arak University Department of Mechanical Engineering Politecnico di Milano

Recently application of functionally graded materials（FGMs） have attracted a great deal of interest. These materials are composed of various materials with different micro-structures which can vary spatially in FGMs. Such composites with varying thickness and non-uniform pressure can be used in the aerospace engineering. Therefore, analysis of such composite is of high importance in engineering problems. Thermoelastic analysis of functionally graded cylinder with variable thickness under non-uniform pressure is considered. First order shear deformation theory and total potential energy approach is applied to obtain the governing equations of non-homogeneous cylinder. Considering the inner and outer solutions, perturbation series are applied to solve the governing equations. Outer solution for out of boundaries and more sensitive variable in inner solution at the boundaries are considered. Combining of inner and outer solution for near and far points from boundaries leads to high accurate displacement field distribution. The main aim of this paper is to show the capability of matched asymptotic solution for different non-homogeneous cylinders with different shapes and different non-uniform pressures. The results can be used to design the optimum thickness of the cylinder and also some properties such as high temperature residence by applying non-homogeneous material.

关键词： non-homogenous cylinder First order Shear Deformation Theory matched asymptotic method perturbation method functionally graded material

Strip Casting of High Performance Structural Alloys

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journal of Rare Earths 2004年第z2期22卷 78-84页

作者： S S Park j G Lee Nack j Kim Center for Advanced Aerospace Materials Pohang University of Science and TechnologyPohang 790-784Korea Center for Advanced Aerospace MaterialsPohang University of Science and TechnologyPohang 790-784Korea Center for Advanced Aerospace MaterialsPohang University of Science and TechnologyPohang 790-784Korea

There exists a great need for the development of high performance alloys due to increasing demands for energy conservation and environmental protection. Application of strip casting shows a strong potential for the improvement of properties of existing alloys and also for the development of novel alloy systems with superior properties. The present paper reviews our Center's activities in the development of high performance alloys by strip casting. Examples include (1) Al alloys, (2) wrought Mg alloys, and (3) bulk metallic glass (BMG) alloys.

关键词： strip casting 6061 Al alloy AZ Mg alloy bulk metallic glass (BMG) alloy dispersion hardening

Crystalline compounds for remediation of rare-earth fission products:A review

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journal of Rare Earths 2022年第3期40卷 365-380,I0001页

作者： Saehwa Chong Brian j.Riley Zayne j.Nelson Pacific Northwest National Laboratory RichlandWA99352USA

Rare earth(RE)-containing crystals have been investigated as media for the immobilization of RE fission products from nuclear waste *** reprocessing of spent nuclear fuel,fission products including REs,alkalis,and alkaline earths released from the *** viable option to immobilize the RE fission products is to incorporate them into chemically durable crystalline phases in specific waste *** study summarizes the crystal structures and synthesis methods of six RE-containing compounds that have applications in remediation of RE fission *** compounds include oxyapatite(AE_(2)RE_(8)(SiO_(4))_(6)O_(2)),oxychloride(REOCl),borosilicate(RE_(3)BSi_(2)O_(10)),pyrochlore(RE_(2)M_(2)O_(7)),monazite(REPO_(4)),and perovskite(REMO_(3))where AE denotes alkaline earth metals and M denotes transition *** review provides an overview of literature on the usage of these six compounds for immobilizing RE fission products and summarizes different synthesis methods for producing these *** of structural parameters with different REs in each compound are also discussed.

关键词： Rare-earth compounds Nuclear waste forms Crystal structures Synthesis of rare-earth compounds

A hybrid multi-degree-of-freedom vibration isolation platform for spacecrafts by the linear active disturbance rejection control

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Applied Mathematics and Mechanics(English Edition) 2020年第5期41卷 805-818页

作者： Weichao CHI S.j.MA j.Q.SUN College of Science Northeastern UniversityShenyang 100819China Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern UniversityShenyang 100819China Department of Mechanical Engineering School of EngineeringUniversity of CaliforniaMercedCA 95343U.S.A.

The hybrid vibration isolation, which takes advantages of both the passive and active approaches, has been an important solution for space missions. The objective of this paper is to design a vibration isolation platform for payloads on spacecrafts with the robust, wide bandwidth, and multi-degree-of-freedom(MDOF). The proposed solution is based on a parallel mechanism with six voice-coil motors(VCMs) as the actuators. The linear active disturbance resistance control(LADRC) algorithm is used for the active control. Numerical simulation results show that the vibration isolation platform performs effectively over a wide bandwidth, and the resonance introduced by the passive isolation is eliminated. The system robustness to the uncertainties of the structure is also verified by simulation.

关键词： hybrid vibration isolation Stewart platform linear active disturbance rejection control(LADRC) stability robustness

Two-fluid modelling for cylindrical fluidized beds using kinetic theory for rough spheres

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Particuology 2020年第3期18卷 25-34页

作者： Lei Yang j.T.Padding j.A.M.Kuipers Helmholtz Institute Erlangen-Nürnberg for Renewable Energy(IEK-11) Fürther Straβe 24890429 NurnbergGermany Department of Process and Energy Delft University of Technology2628CB DelftThe Netherlands Department of Chemical Engineering and Chemistry Eindhoven University of Technology5600MB EindhovenThe Netherlands

Recently,we have extended the kinetic theory of granular flow (KTGF) to include friction between the spherical particles and tested it in rectangular *** this study,the extended KTGF implemented in cylindrical coordinates is used to model the more-commonly employed cylindrical bubbling fluidized *** attention is paid to the anti-symmetric part of the velocity gradient in the solids stress *** verification of the implementation,a comparison of the present model in the limit of zero friction with the original (frictionless) KTGF model was ***,simulations of bubbling fluidized beds of inelastic particles were performed using our extended KTGF and an effective KTGF model for inelastic particles of jenkins and *** simulation results show good agreement for the time-averaged solids volume fraction distribution and solids circulation ***,our model is validated by predicting the individual bubble behavior in dense bubbling fluidized beds containing different granular materials in a comparison with experimental data from Verma et al.(2014).The extended KTGF leads to an improved agreement with experimental bubble *** to previous work (Yang et al.,2016b,2017c),and by introducing cylindrical coordinates,the current work demonstrates that the extended KTGF improves predictions for the temporal bubble behavior of cylindrical fluidized beds.

关键词： Fluidization Frictional collision Rough particles Cylindrical bed hydrodynamics Two-fluid model

Impingement and mixing dynamics of micro-droplets on a solid surface

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Chinese journal of Chemical Engineering 2022年第12期52卷 66-77页

作者： Guina Yi Ziqi Cai Zhengming Gao j.j.Derksen Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of Chemical Resource Engineering School of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China School of Engineering University of AberdeenAberdeen AB243UEUK

The hydrodynamics and mixing during the nonaxisymmetry impingement of a micro-droplet and a sessile droplet of the same fluid are investigated by many-body dissipative particle dynamics(MDPD) *** this work,the range of the impingement angle(θ_(i)) between the impinging droplet and the sessile droplet is 0°-60° and the contact angle is set as 45° or 124°.The droplets impingement and mixing behavior is analyzed based on the droplet internal flow field,the concentration distribution and the time scale of the decay of the kinetic energy of the impinging *** dimensionless total mixing time(τ_(m)) is calculated by a modified mixing *** the Weber number(We) ranging from 5.65 to22.7 and the Ohnesorge number(Oh) ranging from 0.136 to 0.214,we find rm hardly changes with We and ***,θ_(i)and surface wettability are found to have a significant effect on τ_(m).We find that θ_(i)has no clear effect on τ_(m)on a hydrophobic surface,while on the hydrophilic surface,τ_(m)increase with the θ_(i).Thus,reducing the impinging angle is a valid method to shorten the τ_(m).

关键词： Droplets impingement Mixing behavior Mixing time Concentration distribution Many-body dissipative particle dynamics

OSCILLATION AND VARIATION OF THE LAGUERRE HEAT AND POISSON SEMIGROUPS AND RIESZ TRANSFORMS

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Acta Mathematica Scientia 2012年第3期32卷 907-928页

作者： j.j.Betancor R.Crescimbeni j.L.Torrea Departamento de An'aisis Matema'ico Universidad de La Laguna38271-La LagunaTenerifeIslas CanariasSpain Departamento de Matema'ica Universidad Nacional del ComahueBuenos Aires 14008300 Neuqu'enArgentina Departamento de Matem'aticas Facultad de CienciasUniversidad Auto'noma de Madrid28049 MadridSpain

In this article, we study LP-boundedness properties of the oscillation and vari- ation operators for the heat and Poissson semigroup and Riesz transforms in the Laguerre settings. Also, we characterize Hardy spaces as... 详细信息

关键词： Oscillation variation heat Laguerre semigroup Riesz transforms

Plasma density measurement and downstream etching of silicon and silicon oxide in Ar/NF3 mixture remote plasma source

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Plasma Science and Technology 2019年第6期21卷 52-57页

作者： H j YEOM D H CHOI Y S LEE j H KIM D j SEONG S j YOU H C LEE Korea Research Institute of Standards and Science(KRISS) Daejeon 34113 Republic of Korea Department of Physics Chungnam National University Daejeon 34134 Republic of Korea

In this study,plasma density measurements were performed near the plume region of the remote plasma source (RPS) in Ar/NF3 gas mixtures using a microwave cutoff *** measured plasma density is in the range of 1010-1011 cm-3 in the discharge conditions with RPS powers of 2-4 kW and gas pressures of 0.87-4 *** plasma density decreased with increasing gas pressures and RPS powers under various Ar/NF3 mixing *** decrease in the plasma density measured at the fixed measurement position (plume region) can be understood by the reduction of the electron energy relaxation length with increases in the gas pressures and mixing ratio of NF3/(Ar/NF3).We also performed downstream etching of silicon and silicon oxide films in this *** etch rate of the silicon films significantly increases while the silicon oxide is slightly etched with the gas pressures and *** was also found that the etch rate strongly depends on the wafer position on the processing chamber electrode,and that the etch selectivity reached 96-131 in the discharge conditions of RF powers (3730-4180 W) and gas pressures (3.6-4 Torr).

关键词： remote plasma source electron density cutoff probe downstream etch