Multi-axial perfectly matched layer(M-PML),known to have lost the perfect-matching property owing to multi-axial coordinate stretching,has been numerically validated to be long-time stable and it is thus used extensiv...Multi-axial perfectly matched layer(M-PML),known to have lost the perfect-matching property owing to multi-axial coordinate stretching,has been numerically validated to be long-time stable and it is thus used extensively in linear anisotropic wave simulation and in isotropic cases where the PML becomes unstable.We are concerned with the construction of the M-PML for anisotropic wave simulation based on a second order wave equation implemented with the displacement-based numerical method.We address the benefit of the incorrect chain rule,which is implicitly adopted in the previous derivation of the M-PML.We show that using the frequency-shifted stretching function improves the absorbing efficiency of the M-PML for near-grazing incident waves.Then,through multi-axial complex-coordinate stretching the second order anisotropic wave equation in a weak form,we derive a time-domain multi-axial unsplit frequency-shifted PML(M-UFSPML)using the frequency-shifted stretching function and the incorrect chain rule.A new approach is provided to reduce the number of memory variables needed for computing convolution terms in the M-UFSPML.The obtained M-UFSPML is well suited for implementation with a finite element or the spectral element method.By providing several typical examples,we numerically verify the accuracy and long-time stability of the implementation of our M-UFSPML by utilizing the Legendre spectral element method.展开更多
Buoyed by the extensive research on the wide-range biological activities of aminophosphonates, a novel class of aminated (cyclopropylmethyl)phosphor-nates compounds was synthesized from diethyl ((1-(3-chloropropyl)cyc...Buoyed by the extensive research on the wide-range biological activities of aminophosphonates, a novel class of aminated (cyclopropylmethyl)phosphor-nates compounds was synthesized from diethyl ((1-(3-chloropropyl)cyclopropyl)methyl)phosphonate and various amines in the presence of Hunig’s base. Upon biological activity screening these compounds demonstrated encouraging anti-pancreatic cancer properties at low micromolar concentrations.展开更多
We present second-order expressions for the free-surface elevation, velocity potential and pressure resulting from the interaction of surface waves in water of arbitrary depth. When the surface waves have nearly equal...We present second-order expressions for the free-surface elevation, velocity potential and pressure resulting from the interaction of surface waves in water of arbitrary depth. When the surface waves have nearly equal frequencies and nearly opposite directions, a second-order pressure can be felt all the way to the sea bottom. There are at least two areas of applications: reflective structures and microseisms. Microseisms generated by water waves in the ocean are small vibrations of the ground resulting from pressure oscillations associated with the coupling of ocean surface gravity waves and the sea floor. They are recorded on land-based seismic stations throughout the world and they are divided into primary and secondary types, as a function of spectral content. Secondary microseisms are generated by the interaction of surface waves with nearly equal frequencies and nearly opposite directions. The efficiency of microseism generation thus depends in part on ocean wave frequency and direction. Based on the second-order expressions for the dynamic pressure, a simple theoretical analysis that quantifies the degree of nearness in amplitude, frequency, and incidence angle, which must be reached to observe the phenomenon, is presented.展开更多
The sophisticated structures of flapping insect wings make it challenging to study the role of wing flexibility in insect flight.In this study,a mass-spring system is used to model wing structural dynamics as a thin,f...The sophisticated structures of flapping insect wings make it challenging to study the role of wing flexibility in insect flight.In this study,a mass-spring system is used to model wing structural dynamics as a thin,flexible membrane supported by a network of veins.The vein mechanical properties can be estimated based on their diameters and the Young's modulus of cuticle.In order to analyze the effect of wing flexibility,the Young's modulus is varied to make a comparison between two different wing models that we refer to as flexible and highly flexible.The wing models are coupled with a pseudo-spectral code solving the incompressible Navier–Stokes equations,allowing us to investigate the influence of wing deformation on the aerodynamic efficiency of a tethered flapping bumblebee.Compared to the bumblebee model with rigid wings,the one with flexible wings flies more efficiently,characterized by a larger lift-to-power ratio.展开更多
Abstract Accurate simulation of seismic wave propaga- tion in complex geological structures is of particular interest nowadays. However conventional methods may fail to simulate realistic wavefields in environments wi...Abstract Accurate simulation of seismic wave propaga- tion in complex geological structures is of particular interest nowadays. However conventional methods may fail to simulate realistic wavefields in environments with great and rapid structural changes, due for instance to the presence of shadow zones, diffractions and/or edge effects. Different methods, developed to improve seismic model- ing, are typically tested on synthetic configurations against analytical solutions for simple canonical problems or ref- erence methods, or via direct comparison with real data acquired in situ. Such approaches have limitations,especially if the propagation occurs in a complex envi- ronment with strong-contrast reflectors and surface irreg- ularities, as it can be difficult to determine the method which gives the best approximation of the "real" solution, or to interpret the results obtained without an a priori knowledge of the geologic environment. An alternative approach for seismics consists in comparing the synthetic data with high-quality data collected in laboratory experi- ments under controlled conditions for a known configuration. In contrast with numerical experiments, laboratory data possess many of the characteristics of field data, as real waves propagate through models with no numerical approximations. We thus present a comparison of laboratory-scaled measurements of 3D zero-offset wave reflection of broadband pulses from a strong topographic environment immersed in a water tank with numerical data simulated by means of a spectral-element method and a discretized Kirchhoff integral method. The results indicate a good quantitative fit in terms of time arrivals and acceptable fit in amplitudes for all datasets.展开更多
In January 2015,the first quantum homomorphic signature scheme was proposed creatively.However,only one verifier is allowed to verify a signature once in this scheme.In order to support repeatable verification for gen...In January 2015,the first quantum homomorphic signature scheme was proposed creatively.However,only one verifier is allowed to verify a signature once in this scheme.In order to support repeatable verification for general scenario,we propose a new quantum homomorphic signature scheme with repeatable verification by introducing serial verification model and parallel verification model.Serial verification model solves the problem of signature verification by combining key distribution and Bell measurement.Parallel verification model solves the problem of signature duplication by logically treating one particle of an EPR pair as a quantum signature and physically preparing a new EPR pair.These models will be beneficial to the signature verification of general scenarios.Scheme analysis shows that both intermediate verifiers and terminal verifiers can successfully verify signatures in the same operation with fewer resource consumption,and especially the verified signature in entangled states can be used repeatedly.展开更多
A new simple fictitious domain method, the algebraic immersed interface and boundary (AIIB) method, is presented for elliptic equations with immersed interface conditions. This method allows jump conditions on immerse...A new simple fictitious domain method, the algebraic immersed interface and boundary (AIIB) method, is presented for elliptic equations with immersed interface conditions. This method allows jump conditions on immersed interfaces to be discretized with a good accuracy on a compact stencil. Auxiliary unknowns are created at existing grid locations to increase the degrees of freedom of the initial problem. These auxiliary unknowns allow imposing various constraints to the system on interfaces of complex shapes. For instance, the method is able to deal with immersed interfaces for elliptic equations with jump conditions on the solution or discontinuous coefficients with a second order of spatial accuracy. As the AIIB method acts on an algebraic level and only changes the problem matrix, no particular attention to the initial discretization is required. The method can be easily implemented in any structured grid code and can deal with immersed boundary problems too. Several validation problems are presented to demonstrate the interest and accuracy of the method.展开更多
The preparation of medium-sized benzo[b]azocines has always been challenging because of inherently unfavorable enthalpy and entropy factors.This report presents a novel approach for accessing 8-membered seleno-benzo[b...The preparation of medium-sized benzo[b]azocines has always been challenging because of inherently unfavorable enthalpy and entropy factors.This report presents a novel approach for accessing 8-membered seleno-benzo[b]azocines via electrochemically-driven seleno-cyclization.This method enables room-temperature preparation of various structurally diverse medium-sized seleno-benzo[b]azocines.The facile deselenation of the seleno-cyclization products to generate functionalized dienes is an additional benefit of this indispensable reaction.Mechanistic insights are presented based on radical inhibition experiments and cyclic voltammetry measurements,which elucidate the radical pathway.Finally,density functional theory calculations further rationalize the rate-determining step and the unique chemoselectivity observed in this transformation.展开更多
Laser-induced damage(LID)on high-power laser facilities is one of the limiting factors for the increase in power and energy.Inertial confinement fusion(ICF)facilities such as Laser Mégajoule or the National Ignit...Laser-induced damage(LID)on high-power laser facilities is one of the limiting factors for the increase in power and energy.Inertial confinement fusion(ICF)facilities such as Laser Mégajoule or the National Ignition Facility use spectral broadening of the laser pulse that may induce power modulations because of frequency modulation to amplitude modulation conversion.In this paper,we study the impact of low and fast power modulations of laser pulses both experimentally and numerically.The MELBA experimental testbed was used to shape a wide variety of laser pulses and to study their impact on LID.A 1D Lagrangian hydrodynamic code was used to understand the impact of different power profiles on LID.展开更多
The authors study the binary codes spanned by the adjacency matrices of the strongly regular graphs(SRGs)on at most two hundred vertices whose existence is unknown.The authors show that in length less than one hundred...The authors study the binary codes spanned by the adjacency matrices of the strongly regular graphs(SRGs)on at most two hundred vertices whose existence is unknown.The authors show that in length less than one hundred they cannot be cyclic,except for the exceptions of the SRGs of parameters(85,42,20,21)and(96,60,38,36).In particular,the adjacency code of a(85,42,20,21)is the zero-sum code.In the range[100,200]the authors find 29 SRGs that could possibly have a cyclic adjacency code.展开更多
A new notion of bent sequence related to Hadamard matrices was introduced recently,motivated by a security application(Solé,et al.,2021).The authors study the self-dual class in length at most 196.The authors use...A new notion of bent sequence related to Hadamard matrices was introduced recently,motivated by a security application(Solé,et al.,2021).The authors study the self-dual class in length at most 196.The authors use three competing methods of generation:Exhaustion,Linear Algebra and Gr?bner bases.Regular Hadamard matrices and Bush-type Hadamard matrices provide many examples.The authors conjecture that if v is an even perfect square,a self-dual bent sequence of length v always exists.The authors introduce the strong automorphism group of Hadamard matrices,which acts on their associated self-dual bent sequences.The authors give an efficient algorithm to compute that group.展开更多
In this paper we demonstrated a method to reconstruct vector-valued lattice distortion fields within nanoscale crystals by optimization of a forward model of multi-reflection Bragg coherent diffraction imaging(MR-BCDI...In this paper we demonstrated a method to reconstruct vector-valued lattice distortion fields within nanoscale crystals by optimization of a forward model of multi-reflection Bragg coherent diffraction imaging(MR-BCDI)data.The method flexibly accounts for geometric factors that arise when making BCDI measurements,is amenable to efficient inversion with modern optimization toolkits,and allows for globally constraining a single image reconstruction to multiple Bragg peak measurements.This is enabled by a forward model that emulates the multiple Bragg peaks of a MR-BCDI experiment from a single estimate of the 3D crystal sample.We present this forward model,we implement it within the stochastic gradient descent optimization framework,and we demonstrate it with simulated and experimental data of nanocrystals with inhomogeneous internal lattice displacement.We find that utilizing a global optimization approach to MR-BCDI affords a reliable path to convergence of data which is otherwise challenging to reconstruct.展开更多
Coherent Raman scattering microscopy is a fast,label-free,and chemically specific imaging technique that shows high potential for future in vivo optical histology.However,the imaging depth in tissues is limited to the...Coherent Raman scattering microscopy is a fast,label-free,and chemically specific imaging technique that shows high potential for future in vivo optical histology.However,the imaging depth in tissues is limited to the sub-millimeter range because of absorption and scattering.Realization of coherent Raman imaging using a fiber endoscope system is a crucial step towards imaging deep inside living tissues and providing information that is inaccessible with current microscopy tools.Until now,the development of coherent Raman endoscopy has been hampered by several issues,mainly related to the fiber delivery of the excitation pulses and signal collection.Here,we present a flexible,compact,coherent Raman,and multimodal nonlinear endoscope(4.2mm outer diameter,71mm rigid length)based on a resonantly scanned hollow-core Kagomé-lattice double-clad fiber.The fiber design enables distortion-less,background-free delivery of femtosecond excitation pulses and back-collection of nonlinear signals through the same fiber.Sub-micrometer spatial resolution over a large field of view is obtained by combination of a miniature objective lens with a silica microsphere lens inserted into the fiber core.We demonstrate high-resolution,high-contrast coherent anti-Stokes Raman scattering,and second harmonic generation endoscopic imaging of biological tissues over a field of view of 320μm at a rate of 0.8 frames per second.These results pave the way for intraoperative label-free imaging applied to real-time histopathology diagnosis and surgery guidance.展开更多
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 field...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 chemicals.Disentangling the relative contribution of thermal and non-thermal contributions in plasmon-driven processes is,however,difficult.Nanoscale temperature measurements are technically challenging,and macroscale experiments are often characterized by collective heating effects,which tend to make the actual temperature increase unpredictable.This 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 literature.To 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 techniques.These 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.展开更多
Postoperative visual acuity can be limited by post-keratoplasty astigmatism,even with a clear corneal graft.Astigmatism management can be performed by selective suture removal,adjustment of sutures,optical correction,...Postoperative visual acuity can be limited by post-keratoplasty astigmatism,even with a clear corneal graft.Astigmatism management can be performed by selective suture removal,adjustment of sutures,optical correction,photorefractive procedures,wedge resection,intra-ocular lens implantation,intracorneal ring segments,relaxing incisions with or without compression sutures and repeated keratoplasty.Relaxing incisions can be made in the graft,graft-host interface or host cornea.Despite the unpredictability of the method because the flat and steep meridians are usually not orthogonal after penetrating keratoplasty,with asymmetric power distribution,all the studies showed an overall reduction of refractive,keratometric or topographic astigmatism,ranging from 30%to 72%with manual or femtosecond-assisted techniques.Most patients with astigmatism higher than 6 diopters had residual cylinder less than or equal to 3 diopters,which can be treated by laser excimer ablation or secondary intraocular lens implantation.展开更多
Depending on the geometry of the domain, one can define—at least—three different Stokes operators with Dirichlet boundary conditions. We describe how the resolvents of these Stokes operators converge with respect to...Depending on the geometry of the domain, one can define—at least—three different Stokes operators with Dirichlet boundary conditions. We describe how the resolvents of these Stokes operators converge with respect to a converging sequence of domains.展开更多
The authors show that for any ε∈]0, 1[, there exists an analytic outside zero solution to a uniformly elliptic conformal Hessian equation in a ball B ? R^5 which belongs to C^(1,ε)(B) \ C^(1,ε+)(B).
In this paper, the authors prove an analogue of Gibbons' conjecture for the extended fourth order Allen-Cahn equation in R^N, as well as Liouville type results for some solutions converging to the same value at in...In this paper, the authors prove an analogue of Gibbons' conjecture for the extended fourth order Allen-Cahn equation in R^N, as well as Liouville type results for some solutions converging to the same value at infinity in a given direction. The authors also prove a priori bounds and further one-dimensional symmetry and rigidity results for semilinear fourth order elliptic equations with more general nonlinearities.展开更多
Combining polarization modulation Fourier analysis and spatial information in a joint reconstruction algorithm for polarization-resolved fluorescence imaging provides not only a gain in spatial resolution but also a s...Combining polarization modulation Fourier analysis and spatial information in a joint reconstruction algorithm for polarization-resolved fluorescence imaging provides not only a gain in spatial resolution but also a sensitive readout of anisotropy in cell samples.展开更多
Scanning fluorescence microscopes are now able to image large biological samples at high spatial and temporal resolution.This comes at the expense of an increased light dose which is detrimental to fluorophore stabili...Scanning fluorescence microscopes are now able to image large biological samples at high spatial and temporal resolution.This comes at the expense of an increased light dose which is detrimental to fluorophore stability and cell physiology.To highly reduce the light dose,we designed an adaptive scanning fluorescence microscope with a scanning scheme optimized for the unsupervised imaging of cell sheets,which underly the shape of many embryos and organs.The surface of the tissue is first delineated from the acquisition of a very small subset(~0.1%)of sample space,using a robust estimation strategy.Two alternative scanning strategies are then proposed to image the tissue with an improved photon budget,without loss in resolution.The first strategy consists in scanning only a thin shell around the estimated surface of interest,allowing high reduction of light dose when the tissue is curved.The second strategy applies when structures of interest lie at the cell periphery(e.g.adherens junctions).An iterative approach is then used to propagate scanning along cell contours.We demonstrate the benefit of our approach imaging live epithelia from Drosophila melanogaster.On the examples shown,both approaches yield more than a 20-fold reduction in light dose-and up to more than 80-fold-compared to a full scan of the volume.These smart-scanning strategies can be easily implemented on most scanning fluorescent imaging modality.The dramatic reduction in light exposure of the sample should allow prolonged imaging of the live processes under investigation.展开更多
基金Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration under Grant No.2021EEEVL0102National Natural Science Foundation of China under Grant Nos.U2039209 and 51808516+1 种基金the National Key R&D Program of China under Grant No.2018YFC1504004Distinguished Young Scholars Program of the Natural Science Foundation of Heilongjiang province,China under Grant No.YQ2020E005。
文摘Multi-axial perfectly matched layer(M-PML),known to have lost the perfect-matching property owing to multi-axial coordinate stretching,has been numerically validated to be long-time stable and it is thus used extensively in linear anisotropic wave simulation and in isotropic cases where the PML becomes unstable.We are concerned with the construction of the M-PML for anisotropic wave simulation based on a second order wave equation implemented with the displacement-based numerical method.We address the benefit of the incorrect chain rule,which is implicitly adopted in the previous derivation of the M-PML.We show that using the frequency-shifted stretching function improves the absorbing efficiency of the M-PML for near-grazing incident waves.Then,through multi-axial complex-coordinate stretching the second order anisotropic wave equation in a weak form,we derive a time-domain multi-axial unsplit frequency-shifted PML(M-UFSPML)using the frequency-shifted stretching function and the incorrect chain rule.A new approach is provided to reduce the number of memory variables needed for computing convolution terms in the M-UFSPML.The obtained M-UFSPML is well suited for implementation with a finite element or the spectral element method.By providing several typical examples,we numerically verify the accuracy and long-time stability of the implementation of our M-UFSPML by utilizing the Legendre spectral element method.
文摘Buoyed by the extensive research on the wide-range biological activities of aminophosphonates, a novel class of aminated (cyclopropylmethyl)phosphor-nates compounds was synthesized from diethyl ((1-(3-chloropropyl)cyclopropyl)methyl)phosphonate and various amines in the presence of Hunig’s base. Upon biological activity screening these compounds demonstrated encouraging anti-pancreatic cancer properties at low micromolar concentrations.
基金partly supported by the Science Foundation Ireland(SFI)under the research project "High-end computational modeling for wave energy systems"(SFI/10/IN.1/12996)in collaboration with Marine Renewable Energy Ireland(MaREI)the SFI Centre for Marine Renewable Energy Research(SFI/12/RC/2302)
文摘We present second-order expressions for the free-surface elevation, velocity potential and pressure resulting from the interaction of surface waves in water of arbitrary depth. When the surface waves have nearly equal frequencies and nearly opposite directions, a second-order pressure can be felt all the way to the sea bottom. There are at least two areas of applications: reflective structures and microseisms. Microseisms generated by water waves in the ocean are small vibrations of the ground resulting from pressure oscillations associated with the coupling of ocean surface gravity waves and the sea floor. They are recorded on land-based seismic stations throughout the world and they are divided into primary and secondary types, as a function of spectral content. Secondary microseisms are generated by the interaction of surface waves with nearly equal frequencies and nearly opposite directions. The efficiency of microseism generation thus depends in part on ocean wave frequency and direction. Based on the second-order expressions for the dynamic pressure, a simple theoretical analysis that quantifies the degree of nearness in amplitude, frequency, and incidence angle, which must be reached to observe the phenomenon, is presented.
基金Financial support from the Agence Nationale de la Recherche(ANR)(Grant 15-CE40-0019)and Deutsche Forschungsgemeinschaft(DFG)(Grant SE 824/26-1),project AIFITHPC resources of IDRIS under the allocation No.2018-91664 attributed by Grand Equipement National de Calcul Intensif(GENCI)+2 种基金Centre de Calcul Intensif d'Aix-Marseille is acknowledged for granting access to its high performance computing resources financed by the project Equip@Meso(No.ANR-10-EQPX-29-01)financial support granted by the ministeres des Affaires etrangeres et du developpement international(MAEDI)et de l'Education nationale et l'enseignement superieur,de la recherche et de l'innovation(MENESRI),the Deutscher Akademischer Austauschdienst(DAAD)within the French-German Procope project FIFITfinancial support from the JSPS KAKENHI Grant No.JP18K13693。
文摘The sophisticated structures of flapping insect wings make it challenging to study the role of wing flexibility in insect flight.In this study,a mass-spring system is used to model wing structural dynamics as a thin,flexible membrane supported by a network of veins.The vein mechanical properties can be estimated based on their diameters and the Young's modulus of cuticle.In order to analyze the effect of wing flexibility,the Young's modulus is varied to make a comparison between two different wing models that we refer to as flexible and highly flexible.The wing models are coupled with a pseudo-spectral code solving the incompressible Navier–Stokes equations,allowing us to investigate the influence of wing deformation on the aerodynamic efficiency of a tethered flapping bumblebee.Compared to the bumblebee model with rigid wings,the one with flexible wings flies more efficiently,characterized by a larger lift-to-power ratio.
基金the INSIS Institute of the French CNRS,Aix-Marseille Universitythe Carnot Star Institute,the VISTA Projectthe Norwegian Research Council through the ROSE Project for financial support
文摘Abstract Accurate simulation of seismic wave propaga- tion in complex geological structures is of particular interest nowadays. However conventional methods may fail to simulate realistic wavefields in environments with great and rapid structural changes, due for instance to the presence of shadow zones, diffractions and/or edge effects. Different methods, developed to improve seismic model- ing, are typically tested on synthetic configurations against analytical solutions for simple canonical problems or ref- erence methods, or via direct comparison with real data acquired in situ. Such approaches have limitations,especially if the propagation occurs in a complex envi- ronment with strong-contrast reflectors and surface irreg- ularities, as it can be difficult to determine the method which gives the best approximation of the "real" solution, or to interpret the results obtained without an a priori knowledge of the geologic environment. An alternative approach for seismics consists in comparing the synthetic data with high-quality data collected in laboratory experi- ments under controlled conditions for a known configuration. In contrast with numerical experiments, laboratory data possess many of the characteristics of field data, as real waves propagate through models with no numerical approximations. We thus present a comparison of laboratory-scaled measurements of 3D zero-offset wave reflection of broadband pulses from a strong topographic environment immersed in a water tank with numerical data simulated by means of a spectral-element method and a discretized Kirchhoff integral method. The results indicate a good quantitative fit in terms of time arrivals and acceptable fit in amplitudes for all datasets.
基金This project was supported by the National Natural Science Foundation of China(No.61571024)the National Key Research and Development Program of China(No.2016YFC1000307)for valuable helps.
文摘In January 2015,the first quantum homomorphic signature scheme was proposed creatively.However,only one verifier is allowed to verify a signature once in this scheme.In order to support repeatable verification for general scenario,we propose a new quantum homomorphic signature scheme with repeatable verification by introducing serial verification model and parallel verification model.Serial verification model solves the problem of signature verification by combining key distribution and Bell measurement.Parallel verification model solves the problem of signature duplication by logically treating one particle of an EPR pair as a quantum signature and physically preparing a new EPR pair.These models will be beneficial to the signature verification of general scenarios.Scheme analysis shows that both intermediate verifiers and terminal verifiers can successfully verify signatures in the same operation with fewer resource consumption,and especially the verified signature in entangled states can be used repeatedly.
文摘A new simple fictitious domain method, the algebraic immersed interface and boundary (AIIB) method, is presented for elliptic equations with immersed interface conditions. This method allows jump conditions on immersed interfaces to be discretized with a good accuracy on a compact stencil. Auxiliary unknowns are created at existing grid locations to increase the degrees of freedom of the initial problem. These auxiliary unknowns allow imposing various constraints to the system on interfaces of complex shapes. For instance, the method is able to deal with immersed interfaces for elliptic equations with jump conditions on the solution or discontinuous coefficients with a second order of spatial accuracy. As the AIIB method acts on an algebraic level and only changes the problem matrix, no particular attention to the initial discretization is required. The method can be easily implemented in any structured grid code and can deal with immersed boundary problems too. Several validation problems are presented to demonstrate the interest and accuracy of the method.
基金supported by the National Natural Science Foundation of China(No.21801007)Qingchuang Technology Support Program of University in Shandong Province(No.2021KJ066)S.-F.Ni acknowledges funding from the STU Scientific Research Foundation for Talents(No.NTF20022).
文摘The preparation of medium-sized benzo[b]azocines has always been challenging because of inherently unfavorable enthalpy and entropy factors.This report presents a novel approach for accessing 8-membered seleno-benzo[b]azocines via electrochemically-driven seleno-cyclization.This method enables room-temperature preparation of various structurally diverse medium-sized seleno-benzo[b]azocines.The facile deselenation of the seleno-cyclization products to generate functionalized dienes is an additional benefit of this indispensable reaction.Mechanistic insights are presented based on radical inhibition experiments and cyclic voltammetry measurements,which elucidate the radical pathway.Finally,density functional theory calculations further rationalize the rate-determining step and the unique chemoselectivity observed in this transformation.
文摘Laser-induced damage(LID)on high-power laser facilities is one of the limiting factors for the increase in power and energy.Inertial confinement fusion(ICF)facilities such as Laser Mégajoule or the National Ignition Facility use spectral broadening of the laser pulse that may induce power modulations because of frequency modulation to amplitude modulation conversion.In this paper,we study the impact of low and fast power modulations of laser pulses both experimentally and numerically.The MELBA experimental testbed was used to shape a wide variety of laser pulses and to study their impact on LID.A 1D Lagrangian hydrodynamic code was used to understand the impact of different power profiles on LID.
基金supported by the National Natural Science Foundation of China under Grant Nos. 120710012021 University Graduate Research Project under Grant Nos. Y020410077+1 种基金the National Natural Science Foundation of China under Grant No. 12201170the Natural Science Foundation of Anhui Province under Grant No. 2108085QA03
文摘The authors study the binary codes spanned by the adjacency matrices of the strongly regular graphs(SRGs)on at most two hundred vertices whose existence is unknown.The authors show that in length less than one hundred they cannot be cyclic,except for the exceptions of the SRGs of parameters(85,42,20,21)and(96,60,38,36).In particular,the adjacency code of a(85,42,20,21)is the zero-sum code.In the range[100,200]the authors find 29 SRGs that could possibly have a cyclic adjacency code.
基金supported in part by the National Natural Science Foundation of China under Grant No.12071001The work of Dean Crnkovi?is supported by Croatian Science Foundation under the project 6732。
文摘A new notion of bent sequence related to Hadamard matrices was introduced recently,motivated by a security application(Solé,et al.,2021).The authors study the self-dual class in length at most 196.The authors use three competing methods of generation:Exhaustion,Linear Algebra and Gr?bner bases.Regular Hadamard matrices and Bush-type Hadamard matrices provide many examples.The authors conjecture that if v is an even perfect square,a self-dual bent sequence of length v always exists.The authors introduce the strong automorphism group of Hadamard matrices,which acts on their associated self-dual bent sequences.The authors give an efficient algorithm to compute that group.
基金The development of the MR-BCDI forward model and inversion approach,experimental demonstration,and design and fabrication of the SiC nanoparticles was supported by the U.S.Department of Energy(DOE),Office of Science,Basic Energy Sciences,Materials Science and Engineering Division.Additional support for materials preparation came from the Q-NEXT Quantum Center,a U.S.Department of Energy,Office of Science,National Quantum Information Science Research Center,under Award Number DE-FOA-0002253Silicon carbide deterministic nanoparticle fabrication and SEM characterization work was performed under proposals 72483 and 775514 in the Center for Nanoscale Materials clean room.Work performed at the Center for Nanoscale Materials,a U.S+3 种基金Department of Energy Office of Science User Facility,was supported by the U.S.DOE,Office of Basic Energy Sciences,under Contract No.DE-AC02-06CH11357Refinement of the geometric,computational and optimization concepts was supported by the European Research Council(European Union’s Horizon H2020 research and innovation program grant agreement No.724881).Generation of the simulated structures and the BCDI data acquisition was supported by the Laboratory Directed Research and Development(LDRD)funding from Argonne National Laboratory,provided by the Director,Office of Science,of the U.S.Department of Energy under Contract No.DE-AC02-06CH11357This research uses the resources of the Advanced Photon Source,a U.S.DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract No.DE-AC02-06CH11357The authors gratefully acknowledge numerous valuable discussions with Drs.Anthony Rollett,Robert Suter and Matthew Wilkin(Carnegie Mellon University),Nicholas Porter and Dr.Richard Sandberg(Brigham Young University),Dr.Ross Harder(Argonne National Laboratory)and Dr.Anastasios Pateras(DESY).The authors gratefully acknowledge numerous valuable discussions and experimental guidance from Dr.David A.Czaplewski,Suzanne Miller,and Dr.Ralu Divan of the Center of Nanoscale Materials.
文摘In this paper we demonstrated a method to reconstruct vector-valued lattice distortion fields within nanoscale crystals by optimization of a forward model of multi-reflection Bragg coherent diffraction imaging(MR-BCDI)data.The method flexibly accounts for geometric factors that arise when making BCDI measurements,is amenable to efficient inversion with modern optimization toolkits,and allows for globally constraining a single image reconstruction to multiple Bragg peak measurements.This is enabled by a forward model that emulates the multiple Bragg peaks of a MR-BCDI experiment from a single estimate of the 3D crystal sample.We present this forward model,we implement it within the stochastic gradient descent optimization framework,and we demonstrate it with simulated and experimental data of nanocrystals with inhomogeneous internal lattice displacement.We find that utilizing a global optimization approach to MR-BCDI affords a reliable path to convergence of data which is otherwise challenging to reconstruct.
基金supported by EU-ITN-607842-2013-FINON,FR-“Investissement d’Avenir”-11-IDEX-0001-02,11-INSB-0006,11-EQPX-0017,11-LABX-0007,FR-ANR-14-CE17-0004-01,FR-INSERM-PC201508,EU Regional Development Fund(ERDF)Centre National de la Recherche Scientifique(IRCICA USR 3380)the Chinese Science Council(China)for funding support.
文摘Coherent Raman scattering microscopy is a fast,label-free,and chemically specific imaging technique that shows high potential for future in vivo optical histology.However,the imaging depth in tissues is limited to the sub-millimeter range because of absorption and scattering.Realization of coherent Raman imaging using a fiber endoscope system is a crucial step towards imaging deep inside living tissues and providing information that is inaccessible with current microscopy tools.Until now,the development of coherent Raman endoscopy has been hampered by several issues,mainly related to the fiber delivery of the excitation pulses and signal collection.Here,we present a flexible,compact,coherent Raman,and multimodal nonlinear endoscope(4.2mm outer diameter,71mm rigid length)based on a resonantly scanned hollow-core Kagomé-lattice double-clad fiber.The fiber design enables distortion-less,background-free delivery of femtosecond excitation pulses and back-collection of nonlinear signals through the same fiber.Sub-micrometer spatial resolution over a large field of view is obtained by combination of a miniature objective lens with a silica microsphere lens inserted into the fiber core.We demonstrate high-resolution,high-contrast coherent anti-Stokes Raman scattering,and second harmonic generation endoscopic imaging of biological tissues over a field of view of 320μm at a rate of 0.8 frames per second.These results pave the way for intraoperative label-free imaging applied to real-time histopathology diagnosis and surgery guidance.
基金support by the Dutch Research Council(Nederlandse Organisatie voor Wetenschappelijk Onderzoek)via the NWO Vidi award 680-47-550.
文摘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 chemicals.Disentangling the relative contribution of thermal and non-thermal contributions in plasmon-driven processes is,however,difficult.Nanoscale temperature measurements are technically challenging,and macroscale experiments are often characterized by collective heating effects,which tend to make the actual temperature increase unpredictable.This 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 literature.To 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 techniques.These 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.
文摘Postoperative visual acuity can be limited by post-keratoplasty astigmatism,even with a clear corneal graft.Astigmatism management can be performed by selective suture removal,adjustment of sutures,optical correction,photorefractive procedures,wedge resection,intra-ocular lens implantation,intracorneal ring segments,relaxing incisions with or without compression sutures and repeated keratoplasty.Relaxing incisions can be made in the graft,graft-host interface or host cornea.Despite the unpredictability of the method because the flat and steep meridians are usually not orthogonal after penetrating keratoplasty,with asymmetric power distribution,all the studies showed an overall reduction of refractive,keratometric or topographic astigmatism,ranging from 30%to 72%with manual or femtosecond-assisted techniques.Most patients with astigmatism higher than 6 diopters had residual cylinder less than or equal to 3 diopters,which can be treated by laser excimer ablation or secondary intraocular lens implantation.
基金supported by the ANR Project INFAMIE (Grant No. ANR-15-CE40001)
文摘Depending on the geometry of the domain, one can define—at least—three different Stokes operators with Dirichlet boundary conditions. We describe how the resolvents of these Stokes operators converge with respect to a converging sequence of domains.
文摘The authors show that for any ε∈]0, 1[, there exists an analytic outside zero solution to a uniformly elliptic conformal Hessian equation in a ball B ? R^5 which belongs to C^(1,ε)(B) \ C^(1,ε+)(B).
基金carried out in the framework of the Labex Archimède(ANR-11-LABX-0033)the A*MIDEX project(ANR-11-IDEX-0001-02)+6 种基金funded by the "Investissements d’Avenir" French Government program managed by the French National Research Agency(ANR)funding from the European Research Council under the European Union’s Seventh Framework Programme(FP/2007-2013)ERC Grant Agreement n.321186-ReaDiReaction-Diffusion Equations,Propagation and Modelling and from the ANR NONLOCAL project(ANR-14-CE25-0013)supported by INRIA-Team MEPHYSTOMIS F.4508.14(FNRS)PDR T.1110.14F(FNRS)ARC AUWB-2012-12/17-ULB1-IAPAS
文摘In this paper, the authors prove an analogue of Gibbons' conjecture for the extended fourth order Allen-Cahn equation in R^N, as well as Liouville type results for some solutions converging to the same value at infinity in a given direction. The authors also prove a priori bounds and further one-dimensional symmetry and rigidity results for semilinear fourth order elliptic equations with more general nonlinearities.
文摘Combining polarization modulation Fourier analysis and spatial information in a joint reconstruction algorithm for polarization-resolved fluorescence imaging provides not only a gain in spatial resolution but also a sensitive readout of anisotropy in cell samples.
基金This work was funded by the following agencies:Agence Nationale de la Recherche(ANR-18-CE13-028,ANR-17-CE30-0007)Excellence Initiative of Aix-Marseille University-A*Midex(capostromex),a French Investissements d’Avenir programme+4 种基金Centre National de la Recherche Scientifique,Mission pour l’InterdisciplinariteInstitut Carnot starSATT-SudEstThe project leading to this publication has received funding from the“Investissements d’Avenir”French Government program managed by the French National Research Agency(ANR-16-CONV-0001)from Excellence Initiative of Aix-Marseille University-A*MIDEX.
文摘Scanning fluorescence microscopes are now able to image large biological samples at high spatial and temporal resolution.This comes at the expense of an increased light dose which is detrimental to fluorophore stability and cell physiology.To highly reduce the light dose,we designed an adaptive scanning fluorescence microscope with a scanning scheme optimized for the unsupervised imaging of cell sheets,which underly the shape of many embryos and organs.The surface of the tissue is first delineated from the acquisition of a very small subset(~0.1%)of sample space,using a robust estimation strategy.Two alternative scanning strategies are then proposed to image the tissue with an improved photon budget,without loss in resolution.The first strategy consists in scanning only a thin shell around the estimated surface of interest,allowing high reduction of light dose when the tissue is curved.The second strategy applies when structures of interest lie at the cell periphery(e.g.adherens junctions).An iterative approach is then used to propagate scanning along cell contours.We demonstrate the benefit of our approach imaging live epithelia from Drosophila melanogaster.On the examples shown,both approaches yield more than a 20-fold reduction in light dose-and up to more than 80-fold-compared to a full scan of the volume.These smart-scanning strategies can be easily implemented on most scanning fluorescent imaging modality.The dramatic reduction in light exposure of the sample should allow prolonged imaging of the live processes under investigation.