检索结果-南通市图书馆

Constitutive relations for the shear band evolution in granular matter under large strain

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2008年第6期6卷 501-505页

作者： Stefan Luding Multi Scale Mechanics TS CTW UTwente P.O. Box 217 7500 AE Enschede Netherlands

A so-called ＂split-bottom ring shear cell＂ leads to wide shear bands under slow, quasi-static deformation. Unlike normal cylindrical Couette shear cells or rheometers, the bottom plate is split such that the outer part of it can move with the outer wall, while the other part （inner disk） is immobile. From discrete element simulations （DEM）, several continuum fields like the density, velocity, deformation gradient and stress are computed and evaluated with the goal to formulate objective constitutive relations for the powder flow behavior. From a single simulation, by applying time- and （local） space-averaging, a non-linear yield surface is obtained with peculiar stress dependence. The anisotropy is always smaller than the macroscopic friction coefficient. However, the lower bound of anisotropy increases with the strain rate, approaching the maximum according to a stretched exponential with a specific rate that is consistent with a shear path of about one particle diameter.

关键词： Ring shear cell Shear bands DEM simulation Micro-macro transition Objective constitutive relations Yield stress fluid

Endo-microscopy beyond the Abbe and Nyquist limits

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2020年第1期9卷 1246-1257页

作者： Lyubov V.Amitonova Johannes F.de Boer LaserLaB Department of Physics and AstronomyVrije Universiteit AmsterdamDe Boelelaan 10811081 HV AmsterdamThe Netherlands Advanced Research Center for Nanolithography(ARCNL) Science Park 1061098 XG AmsterdamThe Netherlands

For several centuries,far-field optical microscopy has remained a key instrument in many scientific disciplines,including physical,chemical,and biomedical ***,far-field imaging has many limitations:the spatial resolution is controlled by the diffraction of light,and the imaging speed follows the Nyquist–Shannon sampling *** recent development of super-resolution techniques has pushed the limits of spatial ***,these methods typically require complicated setups and long acquisition times and are still not applicable to deeptissue ***,we report imaging through an ultra-thin fibre probe with a spatial resolution beyond the Abbe limit and a temporal resolution beyond the Nyquist limit simultaneously in a simple and compact *** use the random nature of mode coupling in a multimode fibre,the sparsity constraint and compressive sensing *** new approach of super-resolution endo-microscopy does not use any specific properties of the fluorescent label,such as depletion or stochastic activation of the molecular fluorescent state,and therefore can be used for label-free *** demonstrate a spatial resolution more than 2 times better than the diffraction limit and an imaging speed 20 times faster than the Nyquist *** proposed approach can significantly expand the realm of the application of nanoscopy for bioimaging.

关键词： beyond limit fibre

On the mystery of the absence of a spin-orbit gap in scanning tunneling microscopy spectra of germanene

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Semiconductors 2020年第8期41卷 59-62页

作者： Carolien Castenmiller Harold J.W.Zandvliet Physics of Interfaces and Nanomaterials&MESA+Institute for Nanotechnology University of Twente7500AE EnschedeThe Netherlands

Germanene,the germanium analogue of graphene,shares many properties with its carbon *** materials are two-dimensional materials that host Dirac *** are,however,also a few important differences between these two materials:(1)graphene has a planar honeycomb lattice,whereas germanene’s honeycomb lattice is buckled and(2)the spin-orbit gap in germanene is predicted to be about three orders of magnitude larger than the spin-orbit gap in graphene(24 meV for germanene versus 20μeV for graphene).Surprisingly,scanning tunneling spectra recorded on germanene layers synthesized on different substrates do not show any sign of the presence of a spin-orbit *** date the exact origin of the absence of this spin-orbit gap in the scanning tunneling spectra of germanene has remained a *** this work we show that the absence of the spin-orbit gap can be explained by germanene’s exceptionally low work function of only 3.8 *** difference in work function between germanene and the scanning tunneling microscopy tip(the work functions of most commonly used STM tips are in the range of 4.5 to 5.5 eV)gives rise to an electric field in the tunnel *** electric field results in a strong suppression of the size of the spin-orbit gap.

关键词： germanene spin-orbit coupling quantum spin Hall effect two-dimensional Dirac material

Transcomplementation, but not Physical Association of the CC-NB-ARC and LRR Domains of Tomato R Protein Mi-1.2 is Altered by Mutations in the ARC2 Subdomain

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2008年第3期1卷 401-410页

作者： Gerben van Ooijen Gabriele Mayr Mario Albrecht Ben J. C. Cornelissen Frank L.W. Takken Plant Pathology Swammerdam Institute for Life Sciences University of Amsterdam PO Box 94062 1090 GB Amsterdam the Netherlands Max Planck Institute for Informatics Stuhlsatzenhausweg 85 66123 Saarbrücken Germany

Race-specific disease resistance in plants is mediated by Resistance （R） proteins that recognize pathogen at- tack and initiate defence responses. Most R proteins contain a central NB-ARC domain and a C-terminal leucine-rich repeat （LRR） domain. We analyzed the intramolecular interaction of the LRR domain of tomato R protein Mi-1.2 with its N- terminus. We expressed the CC-NB-ARC and LRR parts in trans and analyzed functional transcomplementation and physical interactions. We show that these domains functionally transcomplement when expressed in trans. Known autoactivating LRR domain swaps were found to induce a hypersensitive response （HR） upon co-expression. Likewise, autoactivating mutants in the NB subdomain transcomplemented to induce HR. Point mutations in the ARC2 subdomain that induce strong autoactivation in the full-length Mi-1.2 protein, however, fail to induce HR in the transcomplementation assay, These data indicate distinct functions for the NB-ARC subdomains in induction of HR signalling. Furthermore, dissociation of the LRR is not required to release its negative regulation, as in all combinations of CC-NB-ARC and LRR domains tested, a physical interaction was observed.

关键词： RESISTANCE PROTEIN DISEASE RESISTANCE NUCLEOTIDE-BINDING CELL-DEATH HYPERSENSITIVE RESPONSE

Translating the action of molecular motors to supramolecular polymers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Aggregate

Aggregate 2022年第3期3卷 100-101页

作者： Magda M.J.Dekker Ghislaine Vantomme Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry Eindhoven University of TechnologyEindhovenThe Netherlands

The amplification of asymmetry from the molecular level to the macroscopic scale is an intriguing mechanism operative in natural systems to control complex *** by nature,strategies for transferring chiral information across length scales in purely synthetic systems have been investigated.[1,2]Thereof,chiral molecules are embedded into well-defined ordered supramolecular structures with the dynamics of noncovalent interactions leading to the amplification effect.

关键词： amplification of asymmetry chirality molecular motor supramolecular polymer

Evolution of real area of contact due to combined normal load and sub-surface straining in sheet metal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2021年第4期9卷 840-855页

作者： Meghshyam SHISODE Javad HAZRAT Tanmaya MISHRA Matthijn DE ROOIJ Ton VAN DEN BOOGAAED Nonlinear Solid Mechanics Faculty of Engineering TechnologyUniversity of TwenteEnschede 7522 NBThe Netherlands Surface Technology and Tribology Faculty of Engineering TechnologyUniversity of TwenteEnschede 7522 NBThe Netherlands

Understanding asperity flattening is vital for a reliable macro-scale modeling of friction and *** sheet metal forming processes,sheet surface asperities are deformed due to contact forces between the tools and the *** addition,as the sheet metal is strained while retaining the normal load,the asperity deformation increases *** of the asperities determines the real area of contact which influences the friction and wear at the tool-sheet metal *** real area of contact between two contacting rough surfaces depends on type of loading,material behavior,and topography of the contacting *** this study,an experimental setup is developed to investigate the effect of a combined normal load and sub-surface strain on real area of *** and zinc coated steel sheets(GI)with different coating thicknesses,surface topographies,and substrate materials are used in the experimental *** element(FE)analyses are performed on measured surface profiles to further analyze the behavior observed in the experiments and to understand the effect of surface topography,and coating thickness on the evolution of the real area of ***,an analytical model is presented to determine the real area contact under combined normal load and sub-surface *** results show that accounting for combined normal load and sub-surface straining effects is necessary for accurate predictions of the real area of contact.

关键词： asperity flattening real area of contact sub-surface strain zinc coating sheet metal forming

Electrodynamics of Abrikosov vortices： the field theoretical formulation

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2011年第4期6卷 357-369页

作者： Aron J. Beekman Jan Zaanen Instituut-Lorentz for Theoretical Physics Universiteit Leiden P. O. Box 9506 2300 RA Leiden The Netherlands

Electrodynamic phenomena related to vortices in superconductors have been studied since their prediction by Abrikosov, and seem to hold no fundamental mysteries. However, most of the effects are treated separately, with no guiding principles. We demonstrate that the relativistic vortex worldsheet in spacetime is the object that naturally conveys all electric and magnetic information, for which we obtain simple and concise equations. Breaking Lorentz invariance leads to down-to-earth Abrikosov vortices, and special limits of these equations include for instance dynamic Meissner screening and the AC Josephson relation. On a deeper level, we explore the electrodynamics of two-form sources in the absence of electric monopoles, in which the electromagnetic field strength itself acquires the characteristics of a gauge field. This novel framework leaves room for unexpected surprises .

关键词： Abrikosov vortex, electromagnetism, Maxwell equations, differential geometry multivalued fields

Simple experimental procedures to distinguish photothermal from hot-carrier processes in plasmonics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2020年第1期9卷 974-989页

作者： Guillaume Baffou Ivan Bordacchini Andrea Baldi Romain Quidant Institut Fresnel CNRSAix Marseille UniversityCentrale MarseilleMarseilleFrance ICFO-Institut de Ciencies Fotoniques The Barcelona Institute of Science and Technology08860CastelldefelsBarcelonaSpain DIFFER-Dutch Institute for Fundamental Energy Research De Zaale 205612 AJ EindhovenThe Netherlands Vrije Universiteit Amsterdam De Boelelaan 10811081 HV AmsterdamThe Netherlands ICREA-Institucio Catalana de Recerca i Estudis Avancats 08010 BarcelonaSpain Nanophotonic Systems Laboratory Department of Mechanical and Process EngineeringETH Zurich8092ZurichSwitzerland

Light absorption and scattering of plasmonic metal nanoparticles can lead to non-equilibrium charge carriers,intense electromagnetic near-fields,and heat generation,with promising applications in a vast range of fields,from chemical and physical sensing to nanomedicine and photocatalysis for the sustainable production of fuels and *** the relative contribution of thermal and non-thermal contributions in plasmon-driven processes is,however,*** temperature measurements are technically challenging,and macroscale experiments are often characterized by collective heating effects,which tend to make the actual temperature increase *** work is intended to help the reader experimentally detect and quantify photothermal effects in plasmon-driven chemical reactions,to discriminate their contribution from that due to photochemical processes and to cast a critical eye on the current *** this aim,we review,and in some cases propose,seven simple experimental procedures that do not require the use of complex or expensive thermal microscopy *** proposed procedures are adaptable to a wide range of experiments and fields of research where photothermal effects need to be assessed,such as plasmonic-assisted chemistry,heterogeneous catalysis,photovoltaics,biosensing,and enhanced molecular spectroscopy.

关键词： collective photochemical intense

An international study on implementation and facilitators and barriers for parent-infant closeness in neonatal units

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pediatric Investigation 2022年第3期6卷 179-188页

作者： Nicole R.van Veenendaal Nanon H.M.Labrie Silke Mader Anne A.M.W.van Kempen Sophie R.D.van der Schoor Johannes B.van Goudoever CROWN Study Group Department of Pediatrics and Neonatology OLVGAmsterdamThe Netherlands Amsterdam UMC location Vrije Universiteit and location University of AmsterdamDepartment of PediatricsEmma Children’s HospitalAmsterdamThe Netherlands Department of Language Literature and CommunicationVrije Universiteit AmsterdamAmsterdamThe Netherlands European Foundation for Care of Newborn Infants MunichGermany

Importance:Parent-infant closeness and active parent participation in neonatal care are important for parent and infant ***:To give an overview of current neonatal settings and gain an in-depth understanding of facilitators and barriers to parent-infant closeness,zero-separation,in 19 ***:Neonatal intensive care unit(NICU)professionals,representing 45 NICUs from a range of geographic regions in Europe and Canada,were purposefully selected and interviewed June–December *** analysis was conducted to identify,analyze and report patterns(themes)for parent-infant closeness across the entire series of ***:Parent-infant separation during infant and/or maternity care is very common(42/45 units,93%),despite the implementation of family integrated care(FICare)practices,including parent participation in medical rounds(17/45,38%),structured education sessions for parents(16/45,36%)and structured training for healthcare professionals(22/45,49%).NICU professionals encountered four main themes with facilitators and barriers for parent-infant closeness on and between the hospital,unit,staff,and family level:Culture(jointly held characteristics,values,thinking and behaviors about parental presence and participation in the unit),Collaboration(the act of working together between and within different levels),Capacities(resources and policies),andCoaching(education to acquire and transfer knowledge and skills).Interpretation:Implementing parent-infant closeness in the NICU is still challenging for healthcare *** optimization in neonatal care towards zero-separation and parent-infant closeness can be achieved by enforcing the’’four Cs for Closeness’:Culture,Collaboration,Capacities,andCoaching.

关键词： Parent-infant closeness Family centered care Family integrated care Couplet-care Neonatalogy Parent-collaboration Zero-separation