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Mag.etic control： Switchable ultrahig. mag.etic g.adients at Fe3O4 nanoparticles to enhance solution-phase mass transport

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Nano Research 2015年第10期8卷 3293-3306页

作者： Kamonwad Ng.mchuea Kristina Tschulik richard g. Compton DepartmentofChemistry Physical&TheoreticalChemistryLaboratoryUniversityofOxfordSouthParksRoadOxfordOX13QZUK

Enhancing.mass transport to electrodes is desired in almost all types of electrochemical sensing. electrocatalysis, and energ. storag. or conversion. Here, a method of doing.so by means of the mag.etic g.adient force g.nerated at mag.etic-nanoparticle-modified electrodes is presented. It is shown using.Fe3O4-nanoparticle-modified electrodes that the ultrahig. mag.etic g.adients （〉10^8 T·m^- 1） established at the mag.etized Fe3O4 nanoparticles speed up the transport of reactants and products at the electrode surface. Using.the Fe（Ⅲ）/ Fe（Ⅱ）-hexacyanoferrate redox couple, it is demonstrated that this mass transport enhancement can conveniently and repeatedly be switched on and off by applying.and removing.an external mag.etic properties of mag.etite nanoparticles field, owing.to the superparamag.etic Thus, it is shown for the first time that mag.etic nanoparticles can be used to control mass transport in electrochemical systems. Importantly, this approach does not require any means of mechanical ag.tation and is therefore particularly interesting.for application in micro- and nanofluidic systems and devices.

关键词： superparamag.eficmag.etite nanoparficles nanoparticle-modifiedelectrodes mag.etic field effects mag.etoelectrochemistry

An SPH Framework for Earthquake-Induced Liquefaction Hazard Assessment of g.otechnical Structures

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Computer Modeling.in Eng.neering.& Sciences 2025年第1期142卷 251-277页

作者： Sourabh Mhaski g.V.Ramana Department of Civil Eng.neering Indian Institute of Technology DelhiNew Delhi110016India

Earthquake-induced soil liquefaction poses sig.ificant risks to the stability of g.otechnical structures *** understanding.of the liquefaction trig.ering.and the post-failure larg. deformation behaviour is essential for desig.ing.resilient *** present study develops a Smoothed Particle Hydrodynamics(SPH)framework for earthquake-induced liquefaction hazard assessment of g.otechnical *** coupled flowdeformation behaviour of soils subjected to cyclic loading.is described using.the PM4Sand model implemented in a three-phase,sing.e-layer SPH framework.A stag.ered discretisation scheme based on the stress particle SPH approach is adopted to minimise numerical inaccuracies caused by zero-energ. modes and tensile ***,non-reflecting.boundary conditions for seismic analysis of semi-infinite soil domains using.the SPH method are *** numerical framework is employed for the analysis of cyclic direct simple shear test,seismic analysis of a level g.ound site,and liquefaction-induced failure of the Lower San Fernando *** ag.eement for liquefaction trig.ering.and post-failure behaviour demonstrates that the SPH framework can be utilised to assess the effect of seismic loading.on field-scale g.otechnical *** present study also serves as the basis for future advancements of the SPH method for applications related to earthquake g.otechnical eng.neering.

关键词： Earthquake seismic liquefaction stress particle PM4Sand smoothed particle hydrodynamics(SPH)

A Cilia-inspired Closed-loop Sensor-actuator Array

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Journal of Bionic Eng.neering 2018年第3期15卷 526-532页

作者： James g. H. Whiting.richard Mayne Chris Melhuish Andrew Adamatzky Unconventional Computing.Centre and Bristol Robotics Laboratory University of the West of England Bristol UK

Cilia are fing.r-like cell-surface org.nelles that are used by certain varieties of aquatic unicellular org.nisms for motility, sensing.and obj ect manipulation. Initiated by internal g.nerators and external mechanical and chemical stimuli, coordinated undulations of cilia lead to the motion of a fluid surrounding.the org.nism. This motion transports micro-particles towards an oral cavity and provides motile force. Inspired by the emerg.nt properties of cilia possessed by the pond org.nism P. caudatum, we propose a novel smart surface with closed-loop control using.sensor-actuators pairing. that can manipulate objects. Each vibrating.motor actuator is controlled by a localised microcontroller which utilises proximity sensor information to initiate actuation. The circuit boards are desig.ed to be plug.and-play and are infinitely up-scalable and reconfig.rable. The smart surface is capable of moving.objects at a speed of 7.2 millimetres per second in forward or reverse direction. Further development of this platform will include more anatomically similar biomimetic cilia and control.

关键词： bioinspiration artificial cilia object manipulation sorting.platforms

Could brig.t γ-ray burst optical transients have been recorded historically?

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Research in Astronomy and Astrophysics 2012年第3期12卷 260-268页

作者： richard g. Strom Fu-Yuan Zhao Cheng.Min Zhang National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Netherlands Institute for Radio Astronomy （ASTRON） EO. Box 2 7990 AA DwingelooNetherlands Astronomical Institute University of Amsterdam Netherlands James Cook University Townsviile Queensland Australia

The brig.test optical flash from a γ-ray burst （g.B） was, briefly, a naked- eye object. Several other g.Bs have produced optical transients only slig.tly fainter. We arg.e that, based upon the recently accumulated data from hundreds of g.B transients, many such optical events should have been visible to the unaided eye in the course of human history. The most likely repositories of such observations are histor- ical records from the Orient, and we have located and discuss a number of candidates. We also consider the value of such observations, should any very likely ones be uncovered, to modern astrophysics.

关键词： γ-rays: bursts—optical transients—historical records

Koutecky-Levich analysis applied to nanoparticle modified rotating.disk electrodes： Electrocatalysis or misinterpretation？

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Nano Research 2014年第1期7卷 71-78页

作者： Justus Masa Christopher Batchelor-McAuley Wolfg.ng.Schuhmann richard g. Compton Department of Chemistry Physical and Theoretical Chemistry Laboratory University of Oxford South Parks Road Oxford OX13QZ UK Analytische Chemie and Center for Electrochemical Sciences-CES Ruhr-Universitat Bochum Universitatsstr 150 D-44780 Bochum Germany

The application of naive Koutecky-Levich analysis to micro- and nano-particle modified rotating.disk electrodes of partially covered and non-planar g.ometry is critically analysed. Assuming.strong.overlap of the diffusion fields of the particles such that transport to the entire surface is time-independent and one-dimensional, the observed voltammetric response reflects an apparent electrochemical rate o constant koapp, equal to the true rate constant ko describing.the redox reaction of interest on the surface of the nanoparticles and the ratio,ψ, of the total electroactive surface area to the g.ometric area of the rotating.disk surface. It is demonstrated that Koutecky-Levich analysis is applicable and yields the expected plots of I-1 versus ω-1 where I is the current and ω is the rotation speed but that the values of the electrochemical rate constants inferred are thereof koapp, not ko. Thus, for ψ 〉 1 apparent electrocatalysis mig.t be naively but wrong.y inferred whereas for ψ 〈 1 the deduced electrochemical rate constant will be less than ko. Moreover, the effect of ψ on the observed rotating.disk electrode voltammog.ams is sig.ificant, sig.alling.the need for care in the overly simplistic application of Koutecky-Levich analysis to modified rotating.electrodes, as is commonly applied for example in the analysis of possible oxyg.n reduction catalysts.

关键词： rotating.disk electrodes nanoparticles electrocatalysis electrode kinetics electro-reduction ofoxyg.n Koutecky-Levich analysis

Stepping.up after spinal cord injury:neg.tiating.an obstacle during.walking

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Neural Reg.neration Research 2025年第7期20卷 1919-1929页

作者： Alain Frig.n Charly g.Lecomte Department of Pharmacolog.-Physiolog. Faculty of Medicine and Health SciencesUniversitéde SherbrookeCentre de recherche du Centre Hospitalier Universitaire de SherbrookeSherbrookeQCCanada

Every day walking.consists of frequent voluntary modifications in the g.it pattern to neg.tiate *** spinal cord injury,stepping.over an obstacle becomes *** over an obstacle requires sensorimotor transformations in several structures of the brain,including.the parietal cortex,premotor cortex,and motor *** information and planning.are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain *** spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including.humans,fail to voluntarily modify limb trajectory to step over an ***,in this review,we discuss the neuromechanical control of stepping.over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

关键词： biomechanics locomotion neurophysiolog. obstacle neg.tiation spinal cord injury

Is Compositionality a Trivial Principle？

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Frontiers of Philosophy in China 2013年第1期8卷 140-155页

作者： richard g. Heck, Jr. Department of Philosophy Brown University Providence RI 02912 USA

Primarily a response to Paul Horwich＇s ＂Composition of Meaning.,＂ this paper attempts to refute his claim that compositionality--roug.ly, the idea that the meaning.of a sentence is determined by the meaning. of its parts and how they are there combined--imposes no substantial constraints on semantic theory or on our conception of the meaning. of words or sentences.

关键词： compositionality Horwich meaning semantics

Stable and accurate schemes for smoothed dissipative particle dynamics

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Applied Mathematics and Mechanics(Eng.ish Edition) 2018年第1期39卷 83-102页

作者： g. FAURE g. STOLTZ CEA DAM DIF Arpajon F-91297 France Universite Paris-Est CERMICS (ENPC) INRIA Marne-la-Vallee F-77455 France

Smoothed dissipative particle dynamics （SDPD） is a mesoscopic particle method that allows to select the level of resolution at which a fluid is simulated. The numerical integ.ation of its equations of motion still suffers from the lack of numerical schemes satisfying.all the desired properties such as energ. conservation and stability. Similarities between SDPD and dissipative particle dynamics with energ. （DPDE） con- servation, which is another coarse-g.ained model, enable adaptation of recent numerical schemes developed for DPDE to the SDPD setting. In this article, a Metropolis step in the integ.ation of the fluctuation/dissipation part of SDPD is introduced to improve its stability.

关键词： smoothed dissipative particle dynamics (SDPD) numerical integ.ation Metropolis alg.rithm

Coulometric sizing.of nanoparticles： Cathodic and anodic impact experiments open two independent routes to electrochemical sizing.of Fez04 nanoparticles

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Nano Research 2013年第11期6卷 836-841页

作者： Kristina Tschulik Baptiste Haddou Dario Omanovi Neil V. Rees richard g. Compton Department of Chemistry Physical & Theoretical Chemistry Laboratory Oxford University South Parks Road Oxford OXI 3QZUnited Kingdom Center for Marine and Environmental Research Ruder Boskovic Institute P. O. Box 180 I0001 Zagreb Croatia

Anodic particle coulometry （APC） is a recently established method of sizing.individual metal nanoparticles by oxidising.them during.their impact on a micro electrode. Here it is demonstrated that the application of APC can be extended to sizing.of metal oxide nanoparticles, such as Fe304 mag.etite nanoparticles. Additionally, a new route to electrochemical nanoparticle sizing.is introduced-- cathodic particle coulometry （CPC）. This method uses the reduction of impacting.nanoparticles, e.g., metal oxide nanoparticles, and is demonstrated to yield correct size information for Fe304 nanoparticles. The combination of these two independent electrochemical methods of nanoparticle sizing. allows for purely electrochemical sizing.of sing.e nanoparticles and simultaneous verification of the obtained results.

关键词： nanoparticle sizing Fe3O4 anodic particle coulometry cathodic particle coulometry impact experiments metal oxide nanoparticles