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National Science Review 2020年第8期7卷 1288-1295页

作者： Rui Yu Y.X.Zhao Andreas P.Schnyder School of Physics and Technology Wuhan University National Laboratory of Solid State Microstructures and Department of Physics Nanjing University Collaborative Innovation center of Advanced Microstructures Nanjing University max-planck-Institute for Solid State Research

According to the mathematical classification of topological band structures, there exist a number of fascinating topological states in dimensions larger than three with exotic boundary phenomena and interesting topological responses. While these topological states are not accessible in condensed matter systems, recent works have shown that synthetic systems, such as photonic crystals or electric circuits, can realize higher-dimensional band structures. Here, we argue that, because of its symmetry properties, the 4D spinless topological insulator is particularly well suited for implementation in these synthetic systems. We explicitly construct a 2D electric circuit lattice, whose resonance frequency spectrum simulates the 4D spinless topological insulator. We perform detailed numerical calculations of the circuit lattice and show that the resonance frequency spectrum exhibits pairs of 3D Weyl boundary states, a hallmark of the nontrivial topology. These pairs of 3D Weyl states with the same chirality are protected by classical time-reversal symmetry that squares to +1, which is inherent in the proposed circuit lattice. We also discuss how the simulated 4D topological band structure can be observed in experiments.

关键词： topological circuit 4D topological states 4D topological Hall effect second Chern number Weyl states

Tunable and switchable polarization rotation with non-reciprocal plasmonic thin films at designated wavelengths

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Light(Science & Applications) 2015年第1期4卷 374-380页

作者： Dominik Floess Jessie Y Chin Akihito Kawatani Daniel Dregely Hanns-Ulrich Habermeier Thomas Weiss Harald Giessen th Physics Institute and Research center SCOPE University of Stuttgart70550 StuttgartGermany max planck Institute for Solid State Research 70569 StuttgartGermany

We experimentally demonstrate an ultra-thin plasmonic optical rotator in the visible regime that induces a polarization rotation that is continuously tunable and switchable by an external magnetic *** rotator is a magneto-plasmonic hybrid structure consisting of a magneto-optical EuSe slab and a one-dimensional plasmonic gold *** low temperatures,EuSe possesses a large Verdet constant and exhibits Faraday rotation,which does not saturate over a regime of several *** combining these properties with plasmonic Faraday rotation enhancement,a large tuning range of the polarization rotation of up to 8.4° for a film thickness of 220 nm is ***,through experiments and simulations,we demonstrate that the unique dispersion properties of the structure enable us to tailor the wavelengths of the tunable polarization rotation to arbitrary spectral positions within the transparency window of the magneto-optical *** demonstrated concept might lead to important,highly integrated,non-reciprocal,photonic devices for light modulation,optical isolation,and magnetic field optical *** simple fabrication of EuSe nanostructures by physical vapor deposition opens the way for many potentially interesting magneto-plasmonic systems and three-dimensional magneto-optical metamaterials.

关键词： active tuning Faraday rotation magneto-optics non-reciprocity optical rotator

Fabrication of freestanding Pt nanowires for use as thermal anemometry probes in turbulence measurements

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Microsystems & Nanoengineering 2021年第2期7卷 155-165页

作者： Hai Le-The Christian Küchler Albert van den Berg Eberhard Bodenschatz Detlef Lohse Dominik Krug Physics of Fluids Group MESA+InstituteUniversity of Twente7522 NBEnschedeThe Netherlands BIOS Lab-on-a-Chip Group MESA+InstituteUniversity of Twente7522 NBEnschedeThe Netherlands max planck-university of Twente center for Complex Fluid Dynamics GöttingenGermany max planck Institute for Dynamics and Self-Organization 37077GöttingenGermany

We report a robust fabrication method for patterning freestanding Pt nanowires for use as thermal anemometry probes for small-scale turbulence *** e-beam lithography,high aspect ratio Pt nanowires(~300 nm width,~70µm length,~100 nm thickness)were patterned on the surface of oxidized silicon(Si)*** wet etching processes with dry etching processes,these Pt nanowires were successfully released,rendering them freestanding between two silicon dioxide(SiO2)beams supported on Si ***,the unique design of the bridge holding the device allowed gentle release of the device without damaging the Pt *** total fabrication time was minimized by restricting the use of e-beam lithography to the patterning of the Pt nanowires,while standard photolithography was employed for other parts of the *** demonstrate that the fabricated sensors are suitable for turbulence measurements when operated in constant-current mode.A robust calibration between the output voltage and the fluid velocity was established over the velocity range from 0.5 to 5 m s−1 in a SF6 atmosphere at a pressure of 2 bar and a temperature of 21°*** sensing signal from the nanowires showed negligible drift over a period of several ***,we confirmed that the nanowires can withstand high dynamic pressures by testing them in air at room temperature for velocities up to 55 m s−1.

关键词： nanowires turbulence thermal

Morphological Heredity of Intermetallic Nb_(5)Si_(3)Dendrites in Hypereutectic Nb-Si Based Alloys via Non-Equilibrium Solidification

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Chinese Journal of Mechanical Engineering 2022年第5期35卷 393-400页

作者： Yueling Guo Lina Jia Wenjun Lu Hu Zhang School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Research center of Light‑alloy Materials Frontier Institute of Science and Technology InnovationBeihang UniversityBeijing 100191China max-planck-Institut für Eisenforschung Max‑Planck‑Straße 140237 DüsseldorfGermany

For hypereutectic Nb-Si based alloys,primary Nb_(5)Si_(3)phases typically grow in a faceted mode during equilibrium or near-equilibrium solidification,which damages the ductility and *** address this issue,here we artificially manipulate the growth morphology of Nb_(5)Si_(3)using electron beam surface melting(EBSM)and subsequent annealing *** show that such a non-equilibrium solidification pathway enables the transition from faceted growth to non-faceted dendritic growth of Nb_(5)Si_(3),along with evident microstructure refinement,generation of metastableβ-Nb_(5)Si_(3)phases and elimination of chemical *** transformation fromβ-Nb_(5)Si_(3)toα-Nb_(5)Si_(3)and Nb solid solution(Nbss)particles is triggered by the annealing treatment at 1450°C for 5 ***,we find the annealing-mediated formation of inherited Nb_(5)Si_(3)dendrites that maintain the dendritic morphology of the original as-solidifiedβ-Nb_(5)Si_(3)*** work thus provides a feasible routine to obtain thermally stable and refinedα-Nb_(5)Si_(3)dendrites in hypereutectic Nb-Si based alloys.

关键词： Nb-Si alloy Intermetallics Nb_(5)Si_(3) Rapid solidification Dendritic growth

Small Ubiquitin-Like Modifier Conjugating Enzyme with Active Site Mutation Acts as Dominant Negative Inhibitor of SUMO Conjugation in Arabidopsis

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Journal of integrative Plant Biology 2013年第1期55卷 75-82页

作者： Konstantin Tomanov Christian Hardtke Ruchika Budhiraja Rebecca Hermkes George Coupland Andreas Bachmair Department of Biochemistry and Cell Biology Max F. Perutz Laboratories Center for Molecular Biology University of Vienna Department of Plant Molecular Biology University of Lausanne Department of Plant Developmental Biology Max Planck Institute for Plant Breeding Research

Small ubiquitin-like modifier （SUMO） conjugation affects a broad range of processes in plants, including growth, flower initiation, pathogen defense, and responses to abiotic stress. Here, we investigate in vivo and in vitro a SUMO conjugating enzyme with a Cys to Ser change in the active site, and show that it has a dominant negative effect. In planta expression significantly perturbs normal development, leading to growth retardation, early flowering and gene expression changes. We suggest that the mutant protein can serve as a probe to investigate sumoylation, also in plants for which poor genetic infrastructure precludes analysis via loss-of-function mutants.

关键词： Agroinfection conjugating enzyme dominant-negative active site mutation small ubiquitin-like modifier conjugation small ubiquitin-like modifier.

Lattice Boltzmann Modeling of Advection-Diffusion-Reaction Equations:Pattern Formation Under Uniform Differential Advection

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Communications in Computational Physics 2013年第3期13卷 741-756页

作者： S.G.Ayodele D.Raabe F.Varnik max-planck Institut fur EisenforschungMax-Planck StraBe 140237DusseldorfGermany Interdisciplinary center for Advanced Materials Simulation Ruhr University BochumStiepeler StraBe 12944780 BochumGermany

A lattice Boltzmann model for the study of advection-diffusion-reaction(ADR)problems is *** multiscale expansion analysis,we derive from the LB model the resulting macroscopic *** is shown that a linear equilibrium distribution is sufficient to produce ADR equations within error terms of the order of the Mach number ***,we study spatially varying structures arising from the interaction of advective transport with a cubic autocatalytic reaction-diffusion process under an imposed uniform *** advecting all the present species leads to trivial translation of the Turing patterns,differential advection leads to flow induced instability characterized with traveling stripes with a velocity dependent wave vector parallel to the flow *** from a linear stability analysis of the model equations are found to be in line with these observations.

关键词： Advective transport differential advection Turing patterns linear stability lattice Boltzmann

Systematic characterization of cleanroom-free fabricated macrovalves,demonstrating pumps and mixers for automated fluid handling tuned for organ-on-chip applications

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Microsystems & Nanoengineering 2022年第3期8卷 163-176页

作者： Elsbeth G.B.M.Bossink Anke R.Vollertsen Joshua T.Loessberg-Zahl Andries D.van der Meer Loe l.Segerink Mathieu Odijk BIOs Lab on a Chip Group MESA+instituteTechnical Medical CenterMax Planck Institute for Complex Fluid DynamicsUniversity of TwenteEnschedeThe Netherlands Applied Stem Cell Technologies Group Technical Medical CenterUniversity of TwenteEnschedeThe Netherlands

Integrated valves enable automated control in microfuidic systems,as they can be applied for mixing,pumping and compartmentalization *** automation would be highly valuable for applications in organ-on-chip(OoC)***,OoC systems typically have channel dimensions in the range of hundreds of micrometers,which is an order of magnitude larger than those of typical microfluidic *** most-used fabrication process for integrated,normally open polydimethylsiloxane(PDMS)valves requires a reflow photoresist that limits the achievable channel *** addition,the low stroke volumes of these valves make it challenging to achieve flow rates of microliters per minute,which are typically required in OoC ***,we present a mechanical'macrovalve'fabricated by multilayer soft lithography using micromilled direct *** demonstrate that these valves can close off rounded channels of up to 700μm high and 1000μm ***,we used these macrovalves to create a peristaltic pump with a pumping rate of up to 48μL/min and a mixing and metering device that can achieve the complete mixing of a volume of 6.4μL within only 17 *** initial cell culture experiment demonstrated that a device with integrated macrovalves is biocompatible and allows the cell culture of endothelial cells over multiple days under continuous perfusion and automated medium refreshment.

关键词： pumping mixer pump

Unique biogenesis and kinetics of hornwort Rubiscos revealed by synthetic biology systems

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Molecular Plant 2024年第12期17卷 1833-1849页

作者： Zhen Guo Oh Tanner Ashton Robison Dan Hong Loh Warren Shou Leong Ang Jediael Zheng Ying Ng Fay-Wei Li Laura Helen Gunn School of integrative Plant Science Cornell UniversityIthacaNY 14853USA Boyce Thompson Institute IthacaNY 14853USA max planck Institute for Terrestrial Microbiology 35043 MarburgGermany Department of Cell and Molecular Biology Uppsala University75124 UppsalaSweden

Hornworts are the only land plants that employ a pyrenoid to optimize Rubisco’s CO_(2) fixation,yet hornwort Rubisco remains poorly *** we assembled the hornwort Anthoceros agrestis Rubisco(AaRubisco)using the Arabidopsis thaliana SynBio expression system and observed the formation of stalled intermediates,prompting us to develop a new SynBio system with *** cognate *** successfully assembled AaRubisco and Rubisco from three other hornwort *** *** Rubisco,AaRubisco assembly is not dependent on RbcX or *** characterization reveals that hornwort Rubiscos exhibit a range of catalytic rates(3–10 s−1),but with similar affinity(∼30μM)and specificity(∼70)for CO_(2).These results suggest that hornwort Rubiscos do not comply with the long-held canonical catalytic trade-off observed in other land plants,providing experimental support that Rubisco kinetics may be phylogenetically ***,we observed a 50%increase in AaRubisco catalytic rates when RbcX was removed from our SynBio system,without any reduction in *** biology,biochemistry,and proteomic analysis suggest that subtle differences in Rubisco large-subunit interactions,when RbcX is absent during biogenesis,increases the accessibility of active sites and catalytic turnover ***,this study uncovered a previously unknown Rubisco kinetic parameter space and provides a SynBio chassis to expand the survey of other Rubisco *** discoveries will contribute to developing new approaches for engineering Rubisco with superior kinetics.

关键词： hornworts CO_(2)fixation Rubisco synthetic biology structural biology assembly factors

Message Spreading and Forget-Remember Mechanism on a Scale-Free Network

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Chinese Physics Letters 2008年第6期25卷 2303-2306页

作者：李炜辜娇蔡勖 Complexity Science center and Institute of Particle Physics Huazhong Normal University Wuhan 430079 max-planck-Institute for Mathematics in the Sciences Inselstr. 2204103 Leipzig Germany

We study message spreading on a scale-free network, by introducing a novel forget-remember mechanism. Message, a general term which can refer to email, news, rumor or disease, etc, can be forgotten and remembered by its holder. The way the message is forgotten and remembered is governed by the forget and remember function, F and R, respectively. Both F and R are functions of history time t concerrdng individual＇s previous states, namely being active （with message） or inactive （without message）. Our systematic simulations show at the low transmission rate whether or not the spreading can be efficient is primarily determined by the corresponding parameters for F and R.

关键词： COMPLEX NETWORKS EPIDEMIC