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Self-diffusion coefficients of organic solvents in linear and branched high density polyethylene particles measured by PFG NMR

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Chinese Chemical Letters 2008年第1期19卷 110-114页

作者： Xiao Wei Yan Xiao Hong Ren Siegfried Stap Jing Dai Wang Yong Rong Yang Department of Chemical Engineering Zhejiang University Hangzhou 310027 China FG technische physik ll/polymerphysik Fakultat fiir Mathematik und Naturwissenschaften Technische Universitiit Ilmenau Postfach 100565 D-98684 Ilmenau Germany Institut fiir technische Chemie und Makromolekulare Chemie RWTH Aachen University Worringerweg 1 D-52056 Aachen Germany

Pulsed field gradient nuclear magnetic resonance （PFG NMR） has been performed to study the diffusion of organic solvents into semicrystalline polyethylene particles. Self-diffusion coefficients in different domains of the sample can be extracted through a bi- exponential fit to the echo intensity attenuation, which allows the precise determination of the tortuosity of the polyethylene particles. Further exploration comes from the measurements with branched polyethylene particles and it was found that the diffusion in polymer phase contributed significantly to the slow component of the exponential decay curve. 2007 Jing Dai Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： Self-diffusion coefficients Pulsed field gradient NMR Tortuosity Polyethylene particle

Impact of Die Materials on the Effect of New Polymer Processing Aids for Sharkskin Properties

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Journal of Materials Science and Chemical Engineering 2016年第9期4卷 17-27页

作者： Seyed Pooyan Sajjadi Polymertechnik/polymerphysik Technische Universit at Berlin Berlin Germany

Flows of polymeric liquids undergo instabilities whose origins are quite different from those of Newtonian flows, due to their elastic character and the complexity of the fluid/solid boundary condition. One of these instabilities is well known as “shark-skin” which damages the surface appearance and properties of polymer extrudate while processing in blowmolding or piping, while it can be suppressed by employing various methods including coating the die surface and/or adding Polymer Processing Aid’s (PPA) to the polymer. In this article, the effect of various die materials on the properties of Polyethylene glycol (PEG) as a new type of PPA for suppressing the sharkskin phenomenon has been studied.

关键词： Polymer Processing Aids (PPA) PEG Sharkskin Extrusion Instabilities

Review on Recent Advances of Cathode Materials for Potassium-ion Batteries

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Energy & Environmental Materials 2020年第1期3卷 56-66页

作者： Mo Sha Long Liu Huaping Zhao Yong Lei Fachgebiet Angewandte Nanophysik Institut fur Physik&IMN MacroNano■(ZIK)Technische Universitat IlmenauIlmenauGermany

Potassium-ion batteries(PIBs) as a promising supplement to lithium-ion batteries have drawn great attention attributing to the abundant potassium resources, the fast-ionic conductivity of potassium ions in electrolyte, and the low standard redox potential of potassium. However, the development of PIBs is still in its infancy, which is largely restricted by the fact that the electrode materials, especially the cathode materials of PIBs, are far from satisfactory in practical applications regarding the capacity, voltage, and cycle life. Therefore, most of current research efforts have been devoted to exploring new and high-performance electrode materials for achieving PIBs with high capacity and voltage as well as excellent cyclability. In this review,the recent advancements on cathode materials for PIBs are specially summarized. Besides, technological developments, scientific challenges, and future research opportunities of cathode materials for PIBs are also briefly outlooked.

关键词： cathode materials electrochemical properties potassium-ion batteries recent development

Quantum-optical spectroscopy of a twolevel system using an electrically driven micropillar laser as a resonant excitation source

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Light(Science & Applications) 2018年第1期7卷 681-689页

作者： Sören Kreinberg Tomislav Grbešić Max Strauß Alexander Carmele Monika Emmerling Christian Schneider Sven Höfling Xavier Porte Stephan Reitzenstein Institut für Festkörperphysik Technische Universität Berlin10623 BerlinGermany Institut für Theoretische physik Technische Universität Berlin10623 BerlinGermany technische physik Julius-Maximilians-Universität Würzburg97074 WürzburgGermany SUPA School of Physics and AstronomyUniversity of St AndrewsSt Andrews KY169SSUK

Two-level emitters are the main building blocks of photonic quantum technologies and are model systems for the exploration of quantum optics in the solid *** interesting is the strict resonant excitation of such emitters to control their occupation coherently and to generate close to ideal quantum light,which is of utmost importance for applications in photonic quantum *** date,the approaches and experiments in this field have been performed exclusively using bulky lasers,which hinders the application of resonantly driven two-level emitters in compact photonic quantum *** we address this issue and present a concept for a compact resonantly driven single-photon source by performing quantum-optical spectroscopy of a two-level system using a compact high-βmicrolaser as the excitation *** two-level system is based on a semiconductor quantum dot(QD),which is excited resonantly by a fiber-coupled electrically driven micropillar *** dress the excitonic state of the QD under continuous wave excitation,and trigger the emission of single photons with strong multi-photon suppression(ge2Te0T?0:02)and high photon indistinguishability(V=57±9%)via pulsed resonant excitation at 156 *** results clearly demonstrate the high potential of our resonant excitation scheme,which can pave the way for compact electrically driven quantum light sources with excellent quantum properties to enable the implementation of advanced quantum communication protocols.

关键词： resonant excitation quantum

Emerging smart design of electrodes for micro-supercapacitors:A review

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SmartMat 2022年第3期3卷 447-473页

作者： Jiajia Qiu Huaping Zhao Yong Lei Fachgebiet Angewandte Nanophysik Institut für Physik&IMN MacroNanoTechnische Universität IlmenauIlmenauGermany

Owing to high power density and long cycle life,micro-supercapacitors(MSCs)are regarded as a prevalent energy storage unit for miniaturized electronics in modern life.A major bottleneck is achieving enhanced energy density without sacrificing both power density and cycle *** this end,designing electrodes in a“smart”way has emerged as an effective strategy to achieve a trade-off between the energy and power densities of *** the past few years,considerable research efforts have been devoted to exploring new electrode materials for high capacitance,but designing clever configurations for electrodes has rarely been investigated from a structural point of view,which is also important for MSCs within a limited footprint area,in *** review article categorizes and arranges these“smart”design strategies of electrodes into three design concepts:layer-by-layer,scaffoldassisted and rolling *** corresponding strengths and challenges are comprehensively summarized,and the potential solutions to resolve these challenges are pointed ***,the smart design principle of the electrodes of MSCs and key perspectives for future research in this field are outlined.

关键词： energy density layer-by-layer micro-supercapacitors rolling origami scaffold smart design of electrodes

Anode materials for potassium-ion batteries: Current status and prospects

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Carbon Energy 2020年第3期2卷 350-369页

作者： Mo Sha Long Liu Huaping Zhao Yong Lei Fachgebiet Angewandte Nanophysik Institut für Physik&IMN MacroNano®(ZIK)Technische Universität IlmenauIlmenauGermany

Potassium-ion batteries(KIBs)as one of the most promising alternatives to lithium-ion batteries have been highly valued in recent ***,progress in KIBs is largely restricted by the sluggish development in anode ***,it is imperative to systematically outline and evaluate the recent research advances in the field of anode materials for KIBs toward promoting the development of high-performance anode materials for *** this review,the recent achievements in anode materials for KIBs are *** electrochemical properties(*** storage mechanism,capacity,rate performance,and cycling stability)of these reported anode materials,as well as their advantages/disadvantages,are discerned and analyzed,enabling high-performance KIBs to meet the requirements for practical ***,technological developments,scientific challenges,and future research opportunities of anode materials for KIBs are briefly reviewed.

关键词： anode materials capacity and stability electrochemical properties energy density potassium-ion batteries

Advances on three-dimensional electrodes for micro-supercapacitors:A mini-review

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InfoMat 2019年第1期1卷 74-84页

作者： Long Liu Huaping Zhao Yong Lei Fachgebiet Angewandte Nanophysik Institut für Physik&IMN MacroNano®(ZIK)Technische Universität IlmenauIlmenauGermany

Owing to the high power density,long cycle life and maintain-free,micro-supercapacitors(MSCs)stand out as preferred miniaturized energy source for themiscellaneous autonomous electronic ***,the shortage of energy density is the main stumbling block for their practical *** solve this energy issue,constructing a three-dimensional(3D)electrode within the limited footprint area is proposed as a new solution for improving the energy storage capacity *** the last few years,extensive efforts have been devoted to developing 3D electrodes for MSCs,and significant progress and breakthrough have been ***,there is still lack of systematic summary on the 3D electrode design *** this end,it is imperative to outline the basic design conception,summarize the current states,and discuss the future research about 3D electrodes in MSCs based on the latest development.

关键词： in-plane configuration Internet of Things micro-supercapacitors sandwich configuration threedimensional electrodes

Bistability in Coupled Oscillators Exhibiting Synchronized Dynamics

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Communications in Theoretical Physics 2010年第5期53卷 815-824页

作者： O.I.Olusola U.E.Vincent A.N.Njah J.A.Olowofela Department of Physics University of Agriculture Department of Physics Lancaster University Institut fur Theoretische physik Technische Universitt Clausthal Department of Physics Olabisi Onabanjo University

We report some new results associated with the synchronization behavior of two coupled double-well Duffing oscillators （DDOs）. Some sufficient algebraic criteria for global chaos synchronization of the drive and response DDOs via linear state error feedback control are obtained by means of Lyapunov stability theory. The synchronization is achieved through a bistable state in which a periodic attractor co-exists with a chaotic attractor. Using the linear perturbation analysis, the prevalence of attractors in parameter space and the associated bifurcations are examined. Subcritical and supercritical Hopf bifurcations and abundance of Arnold tongues -- a signature of mode locking phenomenon are found.

关键词： chaos synchronization Duffing oscillator bistability Lyapunov stability theory

Non-Hermitian degeneracies of internal–external mode pairs in dielectric microdisks

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Photonics Research 2019年第4期7卷 464-472页

作者： CHANG-HWAN YI JULIUS KULLIG MARTINA HENTSCHEL JAN WIERSIG Institut für physik Otto-von-Guericke-Universit?t Magdeburg Institut für physik Technische Universit?t Ilmenau

Open quantum and wave systems can exhibit non-Hermitian degeneracies called exceptional points, where both the eigenvalues and the corresponding eigenstates coalesce. Previously, such exceptional points have been investigated in dielectric microcavities in terms of optical modes which are well confined inside the cavity. However,beside these so-called "internal modes" with a relatively high quality factor, there exists another kind of mode called "external modes," which have a large decay rate and almost zero intensity inside the cavity. In the present paper, we demonstrate the physical significance of the external modes via the occurrence of exceptional points of internal–external mode pairs for transverse electric polarization. Our numerical studies show that these exceptional points can be achieved by either a boundary deformation of the microdisk or by introducing absorption into a circular cavity.

关键词： electric optical wave can via Our be