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Stop-and-go waves induced by correlated noise in pedestrian models without inertia

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Journal of Traffic and Transportation Engineering(English Edition) 2020年第1期7卷 52-60页

作者： Antoine Tordeux andreas Schadschneider Sylvain Lassarre School of Mechanical Engineering and Safety Engineering University of WuppertalWuppertal 42119Germany Institute for Theoretical Physics University of CologneCologne 50937Germany Engineering of Surface Transportation Networks and Advanced Computing Laboratory French Institute of Science and Technology for TransportDevelopment and NetworksMarne La Vallee E-77447France

Stop-and-go waves are commonly observed in traffic and pedestrian *** most microscopic traffic models,they occur through a phase transition and instability of the homogeneous solution after fine tuning of *** effects are believed to play an important role in this *** this article,we present a novel explanation for stop-and-go waves based on stochastic effects in the absence of *** model used is a first order optimal velocity(OV)model including an additive stochastic noise.A power spectral analysis for single-file pedestrian trajectories highlights the existence of Brownian speed *** use the Ornstein-Uhlenbeck process to describe such a correlated *** introduction of this specific colored noise in the first order OV model allows describing realistic stop-and-go behavior without requiring instabilities or phase transitions,the homogeneous configurations being systematically stochastically *** compare the stochastic model to deterministic unstable OV models and analyze individual speed autocorrelation to describe the nature of the waves in stationary *** apply the approach to pedestrian single-file motion and compare simulation results to real pedestrian *** simulation results are quantitatively very similar to the real *** discuss plausible values for the model parameters and their meaning.

关键词： Transportation engineering Pedestrian single-file motion Stop-and-go dynamics First order microscopic model Brownian noise Simulation

Between plaza and peak: a montological perspective on verticality and urbanization in highland Peru

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Journal of Mountain Science 2023年第10期20卷 2783-2803页

作者： andreas HALLER Domenico BRANCA Deyvis CANO Institute for Interdisciplinary Mountain Research Austrian Academy of SciencesInnsbruck 6020Austria Department of Humanities and Social Sciences University of SassariSassari 07100Italy Programa Académico de Ingeniería Ambiental Universidad de HuánucoHudnuco 10001Peru

Under the influence of concentrated and extended urbanization,Andean cities and the different altitudinal zones of their“hinterlands”are experiencing profound changes in land cover—from the central plazas up to the highest *** complex regional-geographic characteristics of these socioecological systems,such as the vertical complementarity of land use,require a montological perspective on verticality and urbanization:it transcends disciplinary approaches and can be crucial to properly interpret the trajectories of land cover change and formulate hypotheses for future practiceoriented *** trajectories of land cover change characterized altitudinal zones of Andean cities and their surroundings over the last three decades?Are there similarities that allow for the formulation of more general hypotheses?Using the Peruvian cases of Cusco and Huaraz,and combining a traditional altitudinal zonation model of land use in Peru with direct field observations and GIS-based analyses of remotely sensed data from 1991,2001,2011,and 2021,this study identifies the main trajectories of land cover change in the Quechua(>2300–3500 m),Suni(>3500–4000 m),and Puna(>4000–4800 m)regions—and finds insightful similarities between Cusco and Huaraz:(1)an impressive area of built-up land substitutes grassland in the Quechua,which,following regional altitudinal zonation models,is characterized by irrigated and rain-fed cropland;(2)an unexpected expansion of irrigated cropland takes place in the Suni,which,in theory,often lacks irrigation infrastructure and is mostly used for rain-fed tuber cultivation;and(3)a clear change from“other land”to grassland occurs in the Puna—where grassland is thought to predominate,anyway,since pre-Hispanic *** that these changes reflect the interplay between speculative fallow,agricultural intensification,and ecological restoration,the results can be read as vertically complementary,local manifestations of concentrated and extended urba

关键词： Mountain cities Mountain agriculture Land use change Land cover change Rural-urban linkages Montology

Extending the operational lifetimes of all-direct electron transfer enzymatic biofuel cells by magnetically assembling and exchanging the active biocatalyst layers on stationary electrodes

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Nano Research 2019年第4期12卷 767-775页

作者： Katharina Herkendell andreas Stemmer Ran Tel-Vered Saumerstrasse 4 Nanotechnology Group D-MAVT ETH Zurich Ruschlikon CH-8803 Switzerland

Enzymatic biofuel cells promise green power generation from a variety of natural resources, yet these systems all suffer from time-dependent degradati on effects, in particular progress! ng inactivation of enzymes, which severely limit the operati on al lifetimes of such power sources. To extend operational lifetimes, we introduce a method to magnetically exchange exhausted enzymes for fresh ones. To this end, anodic and cathodic enzymes or enzyme cascades are immobilized on carbon coated magnetic nanoparticles. Under the action of suitable magnetic field gradie nts, these nano particles are assembled on the respective stati onary electrodes, or released from the electrodes for collection and subsequent excha nge. We dem on strate this method on a fructose/oxygen con suming biofuel cell emplo ying fructose dehydroge nase and bilirubin oxidase as well as on anodic and cathodic cascades employing fructose dehydrogenase/invertase and bilirubin oxidase/catalase, respectively. The en zyme-modified nan oparticles support direct electro n transfer bioelectrocatalytic curre nts by wiring the redox active cofactors to the carbonaceous coating and from there to the electrode surfaces. The facile injection, assembly, and removal of enzyme-modified magnetic nan oparticles along with fuel solutio n provides a promisi ng approach to exte nd the operati on al lifetime of enzymatic biofuel cells without the need for exchanging entire systems including chambers and electrodes.

关键词： direct electron transfer magnetic nanoparticle enzymatic biofuel cell recharge lifetime enzyme cascade

Microstructure and physical properties of steel-ladle purging plug refractory materials

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International Journal of Minerals,Metallurgy and Materials 2017年第2期24卷 186-193页

作者： Bin Long Gui-ying Xu Buhr andreas School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Almatis Qingdao Co. Ltd. Qingdao 266071 China Almatis GmbH Frankfurt 60528 Germany

Three different castables were prepared as steel-ladle purging-plug refractory materials： corundum-based low-cement castable （C-LCC）, corundum-spinel-based low-cement castable （C-S-LCC）, and no-cement corundum-spinel castable （C-S-NCC）（hydratable alu- mina p-A1203 bonded）. The properties of these castables were characterized with regard to water demand/flow ability, cold crushing strength （CCS）, cold modulus of rupture （CMoR）, permanent linear change （PLC）, apparent porosity, and hot modulus of rupture （HMoR）. The re- sults show the CCS/CMoR and HMoR of C-LCC and C-S-LCC are greater than those of the castable C-S-NCC. According to the micro- structure analysis, the sintering effect and the bonding type of the matrix material differ among the three castables. The calcium hexaluminate （CA6） phase in the matrix of C-LCC enhances the cold and hot mechanical strengths. In the case of C-S-LCC, the CA6 and 2CaO·2MgO·14A12O3（C2MEA14） ternary phases generated from the matrix can greatly increase the cold and hot mechanical strengths. In the case of the no-cement castable, sintering becomes difficult, resulting in a lower mechanical strength.

关键词： refractory materials purging plugs castable physical properties microstructure

Study of borohydride ionic liquids as hydrogen storage materials

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Journal of Energy Chemistry 2019年第6期28卷 17-21页

作者： Loris Lombardo Heena Yang andreas Züttel Institute of Chemical Sciences and Engineering (ISIC) Basic Science Faculty (SB) école polytechnique fédérale de Lausanne (EPFL) Valais/WallisEnergypolisRue de I'lndustrie 17CH-1951 SionSwitzerland Empa Materials Science and Technology DiibendorfSwitzerland

Stability of borohydrides is determined by the localization of the negative charge on the boron *** liquids(ILs) allow to modify the stability of the borohydrides and promote new dehydrogenation pathways with a lower activation energy. The combination of borohydride and IL is very easy to realize and no expensive rare earth metals are required. The composite of the ILs with complex hydrides decreases the enthalpy and activation energy for the hydrogen desorption. The Coulomb interaction between borohydride and IL leads to a destabilization of the materials with a significantly lower enthalpy for hydrogen desorption. Here, we report a simple ion exchange reaction using various ILs, such as vinylbenzyltrimethylammonium chloride([VBTMA][Cl]), 1-butyl-3-methylimidazolium chloride([bmim][Cl]), and 1-ethyl-1-methylpyrrolidinium bromide([EMPY][Br]) with NaBH4 to decrease the hydrogen desorption temperature. Dehydrogenation of 1-butyl-3-methylimidazolium borohydride([bmim][BH4]) starts below 100℃. The quantity of desorbed hydrogen ranges between 2.4 wt% and 2.9 wt%, which is close to the theoretical content of hydrogen. The improvement in dehydrogenation is due to the strong amine cation that destabilizes borohydride by charge transfer.

关键词： Hydrogen storage Ionic liquid Sodium borohydride Thermolysis

Zinc-ion hybrid supercapacitors with ultrahigh areal and gravimetric energy densities and long cycling life

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Journal of Energy Chemistry 2022年第7期31卷 480-491,I0012页

作者： Ahmad Amiri M.Naraghi andreas A.Polycarpou J.Mike walker’66 mechanical engineering department texas a&m universitycollege stationTX 77843USA department of aerospace engineering texas a&m universitycollege stationTX 77843USA

Zinc ion hybrid supercapacitor (ZIHSC) with promising energy and power densities is an excellent answer to the ever-growing demand for energy storage *** restricted lifespan due to the dendrite formation on metallic zinc (Zn) is one of the main ***,we investigate the electrochemical capability of oxygen-enriched porous carbon nanofibers (A-CNF) and nitrogen,oxygen-enriched porous carbon nanofibers (N-CNF) cathode materials for structural *** this end,a series of samples with different chemical compositions (N and O contents) are prepared to present deep insight into the electrochemical mechanism between N/O doping and Zn-ion *** as-prepared ZIHSC in the presence of N-CNF cathode and Zn Cl_(2) electrolyte offers a battery-level gravimetric energy density of 143.2 Wh kg^(-1)at a power density of 367.1 W kg^(-1).The free-standing N-CNF electrodes in ZIHSCs enjoy delivering an outstanding areal energy density of 110.4μWh cm^(-2)at 0.24 m W cm^(-2),excellent rate capability,and noticeable cycling stability over 10,000 cycles at 10 A g^(-1)with less than 7%*** was also concluded that active pyrrolic N dopants might deliver and facilitate more pseudocapacitance in ZIHSCs than other N configurations,resulting in higher adsorption/desorption and insertion/extraction process of Zn Cl^(+).Taking advantage of the beneficial properties of a free-standing continuous cathode,this novel generation of structural cathode material offers high areal and gravimetric energy densities and mechanical properties in a single zinc-ion-based package.

关键词： Porous carbon nanofibers Zinc chloride electrolyte Zinc ion hybrid supercapacitors Nitrogen-doping Activation Energy density

Highly reactive chemicals meet haploidization

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Molecular Plant 2022年第6期15卷 937-939页

作者： Alevtina Ruban andreas Houben KWS SAAT SE&Co.KGaA Grimsehlstraße 3137574 EinbeckGermany Leibniz Institute of Plant Genetics and Crop Plant Research(IPK)Gatersleben Corrensstraße 306466 Stadt SeelandGermany

The ability to generate(di)haploid plants has provided a strategy to significantly accelerate the crop-breeding *** major advantage of doubled haploids to breeders lies in the simultaneous genetic fixation at every locus within a single generational ***,each doubled haploid(DH)represents a pure line that can be further evaluated for the range of agronomically important *** have been induced mainly through the generation of plants from cultivated gametophytic(haploid)cells,i.e.,in vitro haploid technologies,or through the selective loss of one parental chromosome set upon inter-or intraspecific hybridization,i.e.,in vivo haploid ***,in many crop species,efficient haploid technology is not yet available or only applicable to a limited number of genotypes(reviewed by Jacquier et al.,2020).Due to the limits and costs of current haploid technologies,plant breeders are highly interested in any methodological *** efficient DH production system with low genotype dependency based on the in vivo approach exists so far only in *** haploid-inducing capacity of the inbred line Stock6,originally reported to cause haploid induction rates of 2.3%–3.2%(Coe,1959),was further increased to above 8%in various inducer breeding programs(reviewed by Jacquier et al.,2020).The underlying genetics of the in vivo haploid induction process is quite ***,in recent years significant advances have been made in elucidating the major players.

关键词： breeding doubled Highly

Diverging rationalities between forest fire management services and the general public after the 21st-century mega-fires in Greece

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Journal of Forestry Research 2022年第2期33卷 553-564页

作者： andreas Y.Troumbis Kostas Kalabokidis Palaiologos Palaiologou Department of Environment University of the Aegean81100 MytileneLesvos IslandGreece Department of Geography University of the Aegean81100 MytileneLesvos IslandGreece

Wildfire risk related to hazards on people and assets is expected to increase in the face of climate change,especially in fire-prone environments such as the Mediterranean *** rationalities,i.e.,the complex profile of multi-thematic,wildfire-related perceptions that collectively characterize and quantify all of a society’s responses,its interrelations,and influence on its insights,are of primary importance to understand the degree of preparedness and the direction that wildfire management policies are *** is a country that suffered mega-wildfire events during the first years of the twenty-first *** paper presents a scheme of advanced multivariate statistical procedures applied on standard social survey questionnaires to uncover different or similar rationalities between fire management services and the general ***-centered versus message-oriented rationalities is *** differ mainly on the priorities attributed to strengthening personnel and equipment capacities versus the need for public education and *** are evaluated against the needs of long-term risk assessment and forest management policies in *** main conclusion is that Greek society,although traumatized by recent fire disasters,is not yet prepared for long-term strategic forestry adaptation and planning.

关键词： Wildfire Qualitative research Rationality Fire governance Public Perception Risk assessment

Efficient Algorithms for Approximating Particular Solutions of Elliptic Equations Using Chebyshev Polynomials

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Communications in Computational Physics 2007年第3期2卷 501-521页

作者： andreas Karageorghis Irene Kyza Department of Mathematics and Statistics University of CyprusP.O.Box 205371678 NicosiaCyprus Department of Mathematics University of CreteP.O.Box 2208GR-71409 HeraklionGreece.

In this paper,we propose efficient algorithms for approximating particular solutions of second and fourth order elliptic *** approximation of the particular solution by a truncated series of Chebyshev polynomials and the satisfaction of the differential equation lead to upper triangular block systems,each block being an upper triangular *** systems can be solved efficiently by standard *** numerical examples are presented for each case.

关键词： Chebyshev polynomials Poisson equation biharmonic equation method of particular solutions.