Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing systems.However,the piezoelectric sensor strugg...Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing systems.However,the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix,and achieving sensitivity for detecting micrometer-scale deformations is also challenging.Herein,we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement,capable of detecting minute anisotropic deformations.The as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%,thereby enabling its utility in accurately discerning the 5μm-height wrinkles in thin films and in monitoring human pulse waves.The ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate phase.Additionally,when integrated with machine learning techniques,the sensor’s capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100%accuracy.The structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli,offering a novel perspective for enhancing recognition accuracy.展开更多
In this paper,the problem of brake orbits with minimal period estimates are considered for the first-order Hamiltonian systems with anisotropic growth,i.e.,the Hamiltonian functions may have super-quadratic,sub-quadra...In this paper,the problem of brake orbits with minimal period estimates are considered for the first-order Hamiltonian systems with anisotropic growth,i.e.,the Hamiltonian functions may have super-quadratic,sub-quadratic and quadratic behaviors simultaneously in different variable components.展开更多
Recently,a breakthrough in the high-pressure synthesis of sp^(3)-bonded clathrate-like R-3m-L_(a)B_(8)featuring Latrapped B_(26)cages was achieved.Although the superconducting critical temperature(T_(c))and Vickers ha...Recently,a breakthrough in the high-pressure synthesis of sp^(3)-bonded clathrate-like R-3m-L_(a)B_(8)featuring Latrapped B_(26)cages was achieved.Although the superconducting critical temperature(T_(c))and Vickers hardness(H_(v))of L_(a)B_(8)were estimated,the anisotropic superconductivity and superconducting gap nature remain unclear.The stability of pure B_(26)cages under ambient conditions is of interest for exploring the B_(26)hardness and the role of La atoms in the L_(a)B_(8)hardness.By resolving the Allen–Dynes modified Mc Millan equation and the anisotropic Eliashberg equations,it was found that L_(a)B_(8)exhibits anisotropic single-gap superconductivity with T_(c)=19.0~26.5 K,and the superconducting gap anisotropic ratio reaches 48.50%at 5 K.Most significantly,our work fundamentally validated the coupling of B-2p orbitals with the optical double-degenerate E_(g)phonon modes and A_(g)phonon mode from a novel perspective.The H_(v)of B_(26)cages was determined to be 18.6 GPa,which is lower than that of La-trapped B_(26)cages(i.e.,L_(a)B_(8)),indicating that La acts as a hardness enhancer for L_(a)B_(8).展开更多
P-and S-wave separation plays an important role in elastic reverse-time migration.It can reduce the artifacts caused by crosstalk between different modes and improve image quality.In addition,P-and Swave separation ca...P-and S-wave separation plays an important role in elastic reverse-time migration.It can reduce the artifacts caused by crosstalk between different modes and improve image quality.In addition,P-and Swave separation can also be used to better understand and distinguish wave types in complex media.At present,the methods for separating wave modes in anisotropic media mainly include spatial nonstationary filtering,low-rank approximation,and vector Poisson equation.Most of these methods require multiple Fourier transforms or the calculation of large matrices,which require high computational costs for problems with large scale.In this paper,an efficient method is proposed to separate the wave mode for anisotropic media by using a scalar anisotropic Poisson operator in the spatial domain.For 2D problems,the computational complexity required by this method is 1/2 of the methods based on solving a vector Poisson equation.Therefore,compared with existing methods based on pseudoHelmholtz decomposition operators,this method can significantly reduce the computational cost.Numerical examples also show that the P and S waves decomposed by this method not only have the correct amplitude and phase relative to the input wavefield but also can reduce the computational complexity significantly.展开更多
We analyze the properties of a focused Laguerre–Gaussian(LG)beam propagating through anisotropic ocean turbulence based on the Huygens–Fresnel principle.Under the Rytov approximation theory,we derive the analytical ...We analyze the properties of a focused Laguerre–Gaussian(LG)beam propagating through anisotropic ocean turbulence based on the Huygens–Fresnel principle.Under the Rytov approximation theory,we derive the analytical formula of the channel capacity of the focused LG beam in the anisotropic ocean turbulence,and analyze the relationship between the capacity and the light source parameters as well as the turbulent ocean parameters.It is found that the focusing mirror can greatly enhance the channel capacity of the system at the geometric focal plane in oceanic turbulence.The results also demonstrate that the communication link can obtain high channel capacity by adopting longer beam wavelength,greater initial beam waist radius,and larger number of transmission channels.Further,the capacity of the system increases with the decrease of the mean squared temperature dissipation rate,temperature-salinity contribution ratio and turbulence outer scale factor,and with the increase of the kinetic energy dissipation rate per unit mass of fluid,turbulence inner scale factor and anisotropy factor.Compared to a Hankel–Bessel beam with diffraction-free characteristics and unfocused LG beam,the focused LG beam shows superior anti-turbulence interference properties,which provide a theoretical reference for research and development of underwater optical communication links using focused LG beams.展开更多
The most critical part of a neutron computed tomography(NCT) system is the image processing algorithm,which directly affects the quality and speed of the reconstructed images.Various types of noise in the system can d...The most critical part of a neutron computed tomography(NCT) system is the image processing algorithm,which directly affects the quality and speed of the reconstructed images.Various types of noise in the system can degrade the quality of the reconstructed images.Therefore,to improve the quality of the reconstructed images of NCT systems,efficient image processing algorithms must be used.The anisotropic diffusion filtering(ADF) algorithm can not only effectively suppress the noise in the projection data,but also preserve the image edge structure information by reducing the diffusion at the image edges.Therefore,we propose the application of the ADF algorithm for NCT image reconstruction.To compare the performance of different algorithms in NCT systems,we reconstructed images using the ordered subset simultaneous algebraic reconstruction technique(OS-SART) algorithm with different regular terms as image processing algorithms.In the iterative reconstruction,we selected two image processing algorithms,the Total Variation and split Bregman solved total variation algorithms,for comparison with the performance of the ADF algorithm.Additionally,the filtered back-projection algorithm was used for comparison with an iterative algorithm.By reconstructing the projection data of the numerical and clock models,we compared and analyzed the effects of each algorithm applied in the NCT system.Based on the reconstruction results,OS-SART-ADF outperformed the other algorithms in terms of denoising,preserving the edge structure,and suppressing artifacts.For example,when the 3D Shepp–Logan was reconstructed at 25 views,the root mean square error of OS-SART-ADF was the smallest among the four iterative algorithms,at only 0.0292.The universal quality index,mean structural similarity,and correlation coefficient of the reconstructed image were the largest among all algorithms,with values of 0.9877,0.9878,and 0.9887,respectively.展开更多
The unique in-plane and out-of-plane anisotropy of α-MoO_(3) has attracted considerable interest with regard to potential optoelectronic applications. However, most research has focused on the mid-infrared spectrum, ...The unique in-plane and out-of-plane anisotropy of α-MoO_(3) has attracted considerable interest with regard to potential optoelectronic applications. However, most research has focused on the mid-infrared spectrum, leaving its properties and applications in the visible and near-infrared light spectrum less explored. This study advances the understanding of waveguiding properties of α-MoO_(3) by near-field imaging of the waveguide modes along the [100] and [001] directions of α-MoO_(3) flakes at 633 nm and 785 nm. We investigate the effects of flake thickness and documented the modes' dispersion relationships, which is crucial for tailoring the optical responses of α-MoO_(3) in device applications. Our findings enhance the field of research into α-MoO_(3), highlighting its utility in fabricating next-generation optoelectronic devices due to its unique optically anisotropic waveguide.展开更多
We consider the interior transmission eigenvalue problem corresponding to the scattering for an anisotropic medium of the scalar Helmholtz equation in the case where the boundary?Ωis split into two disjoint parts and...We consider the interior transmission eigenvalue problem corresponding to the scattering for an anisotropic medium of the scalar Helmholtz equation in the case where the boundary?Ωis split into two disjoint parts and possesses different transmission conditions.Using the variational method,we obtain the well posedness of the interior transmission problem,which plays an important role in the proof of the discreteness of eigenvalues.Then we achieve the existence of an infinite discrete set of transmission eigenvalues provided that n≡1,where a fourth order differential operator is applied.In the case of n■1,we show the discreteness of the transmission eigenvalues under restrictive assumptions by the analytic Fredholm theory and the T-coercive method.展开更多
Let X={X(t)∈R^(d),t∈R^(N)}be a centered space-time anisotropic Gaussian field with indices H=(H_(1),…,H_(N))∈(0,1)~N,where the components X_(i)(i=1,…,d)of X are independent,and the canonical metric√(E(X_(i)(t)-X...Let X={X(t)∈R^(d),t∈R^(N)}be a centered space-time anisotropic Gaussian field with indices H=(H_(1),…,H_(N))∈(0,1)~N,where the components X_(i)(i=1,…,d)of X are independent,and the canonical metric√(E(X_(i)(t)-X_(i)(s))^(2))^(1/2)(i=1,…,d)is commensurate with■for s=(s_(1),…,s_(N)),t=(t_(1),…,t_(N))∈R~N,α_(i)∈(0,1],and with the continuous functionγ(·)satisfying certain conditions.First,the upper and lower bounds of the hitting probabilities of X can be derived from the corresponding generalized Hausdorff measure and capacity,which are based on the kernel functions depending explicitly onγ(·).Furthermore,the multiple intersections of the sample paths of two independent centered space-time anisotropic Gaussian fields with different distributions are considered.Our results extend the corresponding results for anisotropic Gaussian fields to a large class of space-time anisotropic Gaussian fields.展开更多
Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in t...Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes.The disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered structure on the structural degradation behavior is unclarified.Herein,we have designed three kinds of LiNi_(0.83)Co_(0.06)Mn_(0.11)O_(2) cathode materials with different primary particle orientations by regulating the precursor coprecipitation process.Combining finite element simulation and in-situ characterization,the Li^(+)transport and structure evolution behaviors of different materials are unraveled.Specifically,the smooth Li^(+)diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution behavior.Meanwhile,the optimized structure evolution ensures radial tight junctions of the primary particles,enabling enhanced Li^(+)diffusion during dynamic processes.Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance.This precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.展开更多
This study aims to discuss anisotropic solutions that are spherically symmetric in the quintessence field,which describe compact stellar objects in the modified Rastall teleparallel theory of gravity.To achieve this g...This study aims to discuss anisotropic solutions that are spherically symmetric in the quintessence field,which describe compact stellar objects in the modified Rastall teleparallel theory of gravity.To achieve this goal,the Krori and Barua arrangement for spherically symmetric components of the line element is incorporated.We explore the field equations by selecting appropriate off-diagonal tetrad fields.Born-Infeld function of torsion f(T)=β√λT+1-1 and power law form h(T)=δTn are used.The Born-Infeld gravity was the first modified teleparallel gravity to discuss inflation.We use the linear equation of state pr=ξρto separate the quintessence density.After obtaining the field equations,we investigate different physical parameters that demonstrate the stability and physical acceptability of the stellar models.We use observational data,such as the mass and radius of the compact star candidates PSRJ 1416-2230,Cen X-3,&4U 1820-30,to ensure the physical plausibility of our findings.展开更多
Doped HfO_(2)-based ferroelectric(FE)films are emerging as leading contenders for next-generation FE nonvolatile memories due to their excellent compatibility with complementary metal oxide semiconductor processes and...Doped HfO_(2)-based ferroelectric(FE)films are emerging as leading contenders for next-generation FE nonvolatile memories due to their excellent compatibility with complementary metal oxide semiconductor processes and robust ferroelectricity at nanoscale dimensions.Despite the considerable attention paid to the FE properties of HfO_(2)-based films in recent years,enhancing their polarization switching speed remains a critical research challenge.We demonstrate the strong ferroelectricity of sub-10nm Hf_(0.5)Zr_(0.5)O_(2)(HZO)thin films and show that the polarization switching speed of these thin films can be significantly affected by HZO thickness and anisotropically strained La_(0.67)Sr_(0.33)MO_(3)-buffered layer.Our observations indicate that the HZO thin film thickness and anisotropically strained La_(0.67)Sr_(0.33)MO_(3)layer influence the nucleation of reverse domains by altering the phase composition of the HZO thin film,thereby reducing the polarization switching time.Although the increase in HZO thickness and anisotropic compressive strain hinder the formation of the FE phase,they can enable faster switching.Our findings suggest that FE HZO ultrathin films with polar orthorhombic structures have broad application prospects in microelectronic devices.These insights into novel methods for increasing polarization switching speed are poised to advance the development of high-performance FE devices.展开更多
Fiber-reinforced composites possess anisotropic mechanical and heat transfer properties due to their anisotropic fibers and structure distribution.In C/Si C composites,the out-of-plane thermal conductivity has mainly ...Fiber-reinforced composites possess anisotropic mechanical and heat transfer properties due to their anisotropic fibers and structure distribution.In C/Si C composites,the out-of-plane thermal conductivity has mainly been studied,whereas the in-plane thermal conductivity has received less attention due to their limited thickness.展开更多
Phonon polaritons(PhPs)exhibit directional in-plane propagation and ultralow losses in van der Waals(vdW)crystals,offering new possibilities for controlling the flow of light at the nanoscale.However,these PhPs,includ...Phonon polaritons(PhPs)exhibit directional in-plane propagation and ultralow losses in van der Waals(vdW)crystals,offering new possibilities for controlling the flow of light at the nanoscale.However,these PhPs,including their directional propagation,are inherently determined by the anisotropic crystal structure of the host materials.Although in-plane anisotropic PhPs can be manipulated by twisting engineering,such as twisting individual vdW slabs,dynamically adjusting their propagation presents a significant challenge.The limited application of the twisted bilayer structure in bare films further restricts its usage.In this study,we present a technique in which anisotropic PhPs supported by bare biaxial vdW slabs can be actively tuned by modifying their local dielectric environment.Excitingly,we predict that the iso-frequency contour of PhPs can be reoriented to enable propagation along forbidden directions when the crystal is placed on a substrate with a moderate negative permittivity.Besides,we systematically investigate the impact of polaritonic coupling on near-field radiative heat transfer(NFRHT)between heterostructures integrated with different substrates that have negative permittivity.Our main findings reveal that through the analysis of dispersion contour and photon transmission coefficient,the excitation and reorientation of the fundamental mode facilitate increased photon tunneling,thereby enhancing heat transfer between heterostructures.Conversely,the annihilation of the fundamental mode hinders heat transfer.Furthermore,we find the enhancement or suppression of radiative energy transport depends on the relative magnitude of the slab thickness and the vacuum gap width.Finally,the effect of negative permittivity substrates on NFRHT along the[001]crystalline direction ofα-MoO3 is considered.The spectral band where the excited fundamental mode resulting from the negative permittivity substrates is shifted to the first Reststrahlen Band(RB 1)ofα-MoO_(3) and is widened,resulting in more significant enhancement of heat flux from RB 1.We anticipate our results will motivate new direction for dynamical tunability of the PhPs in photonic devices.展开更多
The main aim of this article is to study the approximation of a locking-free anisotropic nonconforming finite element for the pure displacement boundary value problem of planar linear elasticity. The optimal error est...The main aim of this article is to study the approximation of a locking-free anisotropic nonconforming finite element for the pure displacement boundary value problem of planar linear elasticity. The optimal error estimates are obtained by using some novel approaches and techniques. The method proposed in this article is robust in the sense that the convergence estimates in the energy and L^2-norms are independent-of the Lame parameter λ.展开更多
Flexible multidirectional strain sensors are crucial to accurately determining the complex strain states involved in emerging sensing applications.Although considerable efforts have been made to construct anisotropic ...Flexible multidirectional strain sensors are crucial to accurately determining the complex strain states involved in emerging sensing applications.Although considerable efforts have been made to construct anisotropic structures for improved selective sensing capabilities,existing anisotropic sensors suffer from a trade-off between high sensitivity and high stretchability with acceptable linearity.Here,an ultrasensitive,highly selective multidirectional sensor is developed by rational design of functionally different anisotropic layers.The bilayer sensor consists of an aligned carbon nanotube(CNT)array assembled on top of a periodically wrinkled and cracked CNT-graphene oxide film.The transversely aligned CNT layer bridge the underlying longitudinal microcracks to effectively discourage their propagation even when highly stretched,leading to superior sensitivity with a gauge factor of 287.6 across a broad linear working range of up to 100%strain.The wrinkles generated through a pre-straining/releasing routine in the direction transverse to CNT alignment is responsible for exceptional selectivity of 6.3,to the benefit of accurate detection of loading directions by the multidirectional sensor.This work proposes a unique approach to leveraging the inherent merits of two cross-influential anisotropic structures to resolve the trade-off among sensitivity,selectivity,and stretchability,demonstrating promising applications in full-range,multi-axis human motion detection for wearable electronics and smart robotics.展开更多
The mechanism of the effects of anisotropic permeability on well patterns and reservoir development are investigated by coordinate transformation, fluid flow analysis, and reservoir development concepts. Anisotropy of...The mechanism of the effects of anisotropic permeability on well patterns and reservoir development are investigated by coordinate transformation, fluid flow analysis, and reservoir development concepts. Anisotropy of permeability has reconstructive effects on well patterns. The originally designed flooding units are broken up, and new pattern units are made up of the wells that belong to different original units. The behavior possesses strong randomness, and leads to a complicated relationship among the injection and production wells, and unpredictable productivity of the formations. To prevent the break-up of well patterns, well lines should be either parallel or perpendicular to the maximum principal direction of the anisotropic permeability （i.e. the fracture direction）. To optimize the development effects ofanisotropic formations, the latitudinal and longitudinal well spacing of the well network are calculated from the principal values of the anisotropic permeability.展开更多
Let p∈（0, 1], q∈（0, ∞] and A be a general expansive matrix on Rn. Let HAp,q （Rn） be the anisotropic Hardy-Lorentz spaces associated with A defined via the non-tangential grand maximal function. In this article,...Let p∈（0, 1], q∈（0, ∞] and A be a general expansive matrix on Rn. Let HAp,q （Rn） be the anisotropic Hardy-Lorentz spaces associated with A defined via the non-tangential grand maximal function. In this article, the authors characterize HAp,q（Rn） in terms of the Lusin-area function, the Littlewood-Paley g-function or the Littlewood-Paley gλ＊-function via first establishing an anisotropic Fefferman-Stein vector-valued inequality in the Lorentz space Lp,q（Rn）. All these characterizations are new even for the classical isotropic Hardy-Lorentz spaces on Rn. Moreover, the range of λ in the gλ＊-function characterization of HAp,q （Rn） coincides with the best known one in the classical Hardy space Hp（Rn） or in the anisotropic Hardy space HAp （Rn）.展开更多
The preparation process of electrically conductive filler for anisotropic conductive adhesive was performed and discussed.The spherical filler contains tri-layer structures: resin core,Ni-P intermediate coating layer,...The preparation process of electrically conductive filler for anisotropic conductive adhesive was performed and discussed.The spherical filler contains tri-layer structures: resin core,Ni-P intermediate coating layer,Au outer coating layer.The 4 μm resin spherical cores were synthesized by monodispersion polymerization method.Then they were contributed to electrical conductivity by electrolessly plating Ni-P layer and gold layer.These particles have good corrosion resistance,high stability,and enough mechanical strength.When mixed with thermosetting epoxy resin to produce anisotropic conductive adhesive(ACA),it can realize a good conductive bonding between bumps on dies and pads on substrates.This environmentally friendly conductive material offers numerous advantages over conventional solder technology and is an ideal substitute for the lead-contained solder in electronics packaging.展开更多
Analytical expressions of electric fields inside and outside an anisotropic dielectric sphere are presented by transforming an anisotropic medium into an isotropic one based on the multi-scale transformation of electr...Analytical expressions of electric fields inside and outside an anisotropic dielectric sphere are presented by transforming an anisotropic medium into an isotropic one based on the multi-scale transformation of electromagnetic theory. The theoretical expressions are consistent with those in the literature. The inside electric field, the outside electric field and the angle between their directions are derived in detail. Numerical simulations show that the direction of the outside field influences the magnitude of the inside field, while the dielectric constant tensor greatly affects its direction.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2022YFA1205300 and No.2022YFA1205304)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(SL2022ZD103).
文摘Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing systems.However,the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix,and achieving sensitivity for detecting micrometer-scale deformations is also challenging.Herein,we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement,capable of detecting minute anisotropic deformations.The as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%,thereby enabling its utility in accurately discerning the 5μm-height wrinkles in thin films and in monitoring human pulse waves.The ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate phase.Additionally,when integrated with machine learning techniques,the sensor’s capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100%accuracy.The structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli,offering a novel perspective for enhancing recognition accuracy.
基金supported by the NSFC(12301138)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2021L377)+1 种基金the Doctoral Scientific Research Foundation of Shanxi Datong University(2018-B-15)The second author’s work was supported by the NSFC(12171108).
文摘In this paper,the problem of brake orbits with minimal period estimates are considered for the first-order Hamiltonian systems with anisotropic growth,i.e.,the Hamiltonian functions may have super-quadratic,sub-quadratic and quadratic behaviors simultaneously in different variable components.
基金supported by the National Natural Science Foundation of China(Grant Nos.11904067,12122405,52072188,1227416951632002)。
文摘Recently,a breakthrough in the high-pressure synthesis of sp^(3)-bonded clathrate-like R-3m-L_(a)B_(8)featuring Latrapped B_(26)cages was achieved.Although the superconducting critical temperature(T_(c))and Vickers hardness(H_(v))of L_(a)B_(8)were estimated,the anisotropic superconductivity and superconducting gap nature remain unclear.The stability of pure B_(26)cages under ambient conditions is of interest for exploring the B_(26)hardness and the role of La atoms in the L_(a)B_(8)hardness.By resolving the Allen–Dynes modified Mc Millan equation and the anisotropic Eliashberg equations,it was found that L_(a)B_(8)exhibits anisotropic single-gap superconductivity with T_(c)=19.0~26.5 K,and the superconducting gap anisotropic ratio reaches 48.50%at 5 K.Most significantly,our work fundamentally validated the coupling of B-2p orbitals with the optical double-degenerate E_(g)phonon modes and A_(g)phonon mode from a novel perspective.The H_(v)of B_(26)cages was determined to be 18.6 GPa,which is lower than that of La-trapped B_(26)cages(i.e.,L_(a)B_(8)),indicating that La acts as a hardness enhancer for L_(a)B_(8).
基金supported by the National Key R&D Program of China(No.2018YFA0702505)the project of CNOOC Limited(Grant No.CNOOC-KJ GJHXJSGG YF 2022-01)+1 种基金R&D Department of China National Petroleum Corporation(Investigations on fundamental experiments and advanced theoretical methods in geophysical prospecting application,2022DQ0604-02)NSFC(Grant Nos.U23B20159,41974142,42074129,12001311)。
文摘P-and S-wave separation plays an important role in elastic reverse-time migration.It can reduce the artifacts caused by crosstalk between different modes and improve image quality.In addition,P-and Swave separation can also be used to better understand and distinguish wave types in complex media.At present,the methods for separating wave modes in anisotropic media mainly include spatial nonstationary filtering,low-rank approximation,and vector Poisson equation.Most of these methods require multiple Fourier transforms or the calculation of large matrices,which require high computational costs for problems with large scale.In this paper,an efficient method is proposed to separate the wave mode for anisotropic media by using a scalar anisotropic Poisson operator in the spatial domain.For 2D problems,the computational complexity required by this method is 1/2 of the methods based on solving a vector Poisson equation.Therefore,compared with existing methods based on pseudoHelmholtz decomposition operators,this method can significantly reduce the computational cost.Numerical examples also show that the P and S waves decomposed by this method not only have the correct amplitude and phase relative to the input wavefield but also can reduce the computational complexity significantly.
基金This work was supported by the Science and Technology Innovation Training Program of Nanjing University of Posts and Telecommunications(Grant No.CXXZD2023080)the National Natural Science Foundation of China(Grant Nos.61871234 and 62001249)+1 种基金the Natural Science Foundation of Nanjing University of Posts and Telecommunications(Grant No.NY222133)the Open Research Fund of National Laboratory of Solid State Microstructures(Grant No.M36055).
文摘We analyze the properties of a focused Laguerre–Gaussian(LG)beam propagating through anisotropic ocean turbulence based on the Huygens–Fresnel principle.Under the Rytov approximation theory,we derive the analytical formula of the channel capacity of the focused LG beam in the anisotropic ocean turbulence,and analyze the relationship between the capacity and the light source parameters as well as the turbulent ocean parameters.It is found that the focusing mirror can greatly enhance the channel capacity of the system at the geometric focal plane in oceanic turbulence.The results also demonstrate that the communication link can obtain high channel capacity by adopting longer beam wavelength,greater initial beam waist radius,and larger number of transmission channels.Further,the capacity of the system increases with the decrease of the mean squared temperature dissipation rate,temperature-salinity contribution ratio and turbulence outer scale factor,and with the increase of the kinetic energy dissipation rate per unit mass of fluid,turbulence inner scale factor and anisotropy factor.Compared to a Hankel–Bessel beam with diffraction-free characteristics and unfocused LG beam,the focused LG beam shows superior anti-turbulence interference properties,which provide a theoretical reference for research and development of underwater optical communication links using focused LG beams.
基金supported by the National Key Research and Development Program of China (No. 2022YFB1902700)the National Natural Science Foundation of China (No. 11875129)+3 种基金the Fund of the State Key Laboratory of Intense Pulsed Radiation Simulation and Effect (No. SKLIPR1810)Fund of Innovation Center of Radiation Application (No. KFZC2020020402)Fund of the State Key Laboratory of Nuclear Physics and Technology,Peking University (No. NPT2020KFY08)the Joint Innovation Fund of China National Uranium Co.,Ltd.,State Key Laboratory of Nuclear Resources and Environment,East China University of Technology (No. 2022NRE-LH-02)。
文摘The most critical part of a neutron computed tomography(NCT) system is the image processing algorithm,which directly affects the quality and speed of the reconstructed images.Various types of noise in the system can degrade the quality of the reconstructed images.Therefore,to improve the quality of the reconstructed images of NCT systems,efficient image processing algorithms must be used.The anisotropic diffusion filtering(ADF) algorithm can not only effectively suppress the noise in the projection data,but also preserve the image edge structure information by reducing the diffusion at the image edges.Therefore,we propose the application of the ADF algorithm for NCT image reconstruction.To compare the performance of different algorithms in NCT systems,we reconstructed images using the ordered subset simultaneous algebraic reconstruction technique(OS-SART) algorithm with different regular terms as image processing algorithms.In the iterative reconstruction,we selected two image processing algorithms,the Total Variation and split Bregman solved total variation algorithms,for comparison with the performance of the ADF algorithm.Additionally,the filtered back-projection algorithm was used for comparison with an iterative algorithm.By reconstructing the projection data of the numerical and clock models,we compared and analyzed the effects of each algorithm applied in the NCT system.Based on the reconstruction results,OS-SART-ADF outperformed the other algorithms in terms of denoising,preserving the edge structure,and suppressing artifacts.For example,when the 3D Shepp–Logan was reconstructed at 25 views,the root mean square error of OS-SART-ADF was the smallest among the four iterative algorithms,at only 0.0292.The universal quality index,mean structural similarity,and correlation coefficient of the reconstructed image were the largest among all algorithms,with values of 0.9877,0.9878,and 0.9887,respectively.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFA1203500)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB30000000)the CAS Youth Interdisciplinary Team。
文摘The unique in-plane and out-of-plane anisotropy of α-MoO_(3) has attracted considerable interest with regard to potential optoelectronic applications. However, most research has focused on the mid-infrared spectrum, leaving its properties and applications in the visible and near-infrared light spectrum less explored. This study advances the understanding of waveguiding properties of α-MoO_(3) by near-field imaging of the waveguide modes along the [100] and [001] directions of α-MoO_(3) flakes at 633 nm and 785 nm. We investigate the effects of flake thickness and documented the modes' dispersion relationships, which is crucial for tailoring the optical responses of α-MoO_(3) in device applications. Our findings enhance the field of research into α-MoO_(3), highlighting its utility in fabricating next-generation optoelectronic devices due to its unique optically anisotropic waveguide.
基金supported by the National Natural Science Foundation of China(11571132,12301542)the Natural Science Foundation of Hubei(2022CFB725)the Natural Science Foundation of Yichang(A23-2-027)。
文摘We consider the interior transmission eigenvalue problem corresponding to the scattering for an anisotropic medium of the scalar Helmholtz equation in the case where the boundary?Ωis split into two disjoint parts and possesses different transmission conditions.Using the variational method,we obtain the well posedness of the interior transmission problem,which plays an important role in the proof of the discreteness of eigenvalues.Then we achieve the existence of an infinite discrete set of transmission eigenvalues provided that n≡1,where a fourth order differential operator is applied.In the case of n■1,we show the discreteness of the transmission eigenvalues under restrictive assumptions by the analytic Fredholm theory and the T-coercive method.
基金supported by the National Natural Science Foundation of China(12371150,11971432)the Natural Science Foundation of Zhejiang Province(LY21G010003)+2 种基金the Management Project of"Digital+"Discipline Construction of Zhejiang Gongshang University(SZJ2022A012,SZJ2022B017)the Characteristic&Preponderant Discipline of Key Construction Universities in Zhejiang Province(Zhejiang Gongshang University-Statistics)the Scientific Research Projects of Universities in Anhui Province(2022AH050955)。
文摘Let X={X(t)∈R^(d),t∈R^(N)}be a centered space-time anisotropic Gaussian field with indices H=(H_(1),…,H_(N))∈(0,1)~N,where the components X_(i)(i=1,…,d)of X are independent,and the canonical metric√(E(X_(i)(t)-X_(i)(s))^(2))^(1/2)(i=1,…,d)is commensurate with■for s=(s_(1),…,s_(N)),t=(t_(1),…,t_(N))∈R~N,α_(i)∈(0,1],and with the continuous functionγ(·)satisfying certain conditions.First,the upper and lower bounds of the hitting probabilities of X can be derived from the corresponding generalized Hausdorff measure and capacity,which are based on the kernel functions depending explicitly onγ(·).Furthermore,the multiple intersections of the sample paths of two independent centered space-time anisotropic Gaussian fields with different distributions are considered.Our results extend the corresponding results for anisotropic Gaussian fields to a large class of space-time anisotropic Gaussian fields.
基金supported by National Natural Science Foundation of China (52070194,52073309)Natural Science Foundation of Hunan Province (2022JJ20069)。
文摘Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes.The disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered structure on the structural degradation behavior is unclarified.Herein,we have designed three kinds of LiNi_(0.83)Co_(0.06)Mn_(0.11)O_(2) cathode materials with different primary particle orientations by regulating the precursor coprecipitation process.Combining finite element simulation and in-situ characterization,the Li^(+)transport and structure evolution behaviors of different materials are unraveled.Specifically,the smooth Li^(+)diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution behavior.Meanwhile,the optimized structure evolution ensures radial tight junctions of the primary particles,enabling enhanced Li^(+)diffusion during dynamic processes.Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance.This precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.
基金funded by the National Natural Science Foundation of China (Grant No. 11975145)
文摘This study aims to discuss anisotropic solutions that are spherically symmetric in the quintessence field,which describe compact stellar objects in the modified Rastall teleparallel theory of gravity.To achieve this goal,the Krori and Barua arrangement for spherically symmetric components of the line element is incorporated.We explore the field equations by selecting appropriate off-diagonal tetrad fields.Born-Infeld function of torsion f(T)=β√λT+1-1 and power law form h(T)=δTn are used.The Born-Infeld gravity was the first modified teleparallel gravity to discuss inflation.We use the linear equation of state pr=ξρto separate the quintessence density.After obtaining the field equations,we investigate different physical parameters that demonstrate the stability and physical acceptability of the stellar models.We use observational data,such as the mass and radius of the compact star candidates PSRJ 1416-2230,Cen X-3,&4U 1820-30,to ensure the physical plausibility of our findings.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406404 and 2020YFA0309100)the National Natural Science Foundation of China(Grant Nos.12074365,12374094,12304153,U2032218,and 11974326),the National Natural Science Foundation of China(Grant No.12274120)+4 种基金CAS Project for Young Scientists in Basic Research(Grant No.YSBR-084)the Fundamental Research Funds for the Central Universities(Grant Nos.WK9990000102 and WK2030000035)Anhui Provincial Natural Science Foundation(Grant No.2308085MA15)Hefei Science Center CAS Foundation(Grant Nos.2021HSC-CIP017 and 2016HSC-IU06)the China Postdoctoral Science Foundation(Grant No.2022M713060)。
文摘Doped HfO_(2)-based ferroelectric(FE)films are emerging as leading contenders for next-generation FE nonvolatile memories due to their excellent compatibility with complementary metal oxide semiconductor processes and robust ferroelectricity at nanoscale dimensions.Despite the considerable attention paid to the FE properties of HfO_(2)-based films in recent years,enhancing their polarization switching speed remains a critical research challenge.We demonstrate the strong ferroelectricity of sub-10nm Hf_(0.5)Zr_(0.5)O_(2)(HZO)thin films and show that the polarization switching speed of these thin films can be significantly affected by HZO thickness and anisotropically strained La_(0.67)Sr_(0.33)MO_(3)-buffered layer.Our observations indicate that the HZO thin film thickness and anisotropically strained La_(0.67)Sr_(0.33)MO_(3)layer influence the nucleation of reverse domains by altering the phase composition of the HZO thin film,thereby reducing the polarization switching time.Although the increase in HZO thickness and anisotropic compressive strain hinder the formation of the FE phase,they can enable faster switching.Our findings suggest that FE HZO ultrathin films with polar orthorhombic structures have broad application prospects in microelectronic devices.These insights into novel methods for increasing polarization switching speed are poised to advance the development of high-performance FE devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.52276086 and 52130604)the Basic Research Program of China(Grant No.514010303-102)the K.C.Wong Education Foundation。
文摘Fiber-reinforced composites possess anisotropic mechanical and heat transfer properties due to their anisotropic fibers and structure distribution.In C/Si C composites,the out-of-plane thermal conductivity has mainly been studied,whereas the in-plane thermal conductivity has received less attention due to their limited thickness.
基金supported by the National Natural Science Foundation of China(Nos.52106099 and 51576004)the Natural Science Foundation of Shandong Province(No.ZR2022YQ57)the Taishan Scholars Program.
文摘Phonon polaritons(PhPs)exhibit directional in-plane propagation and ultralow losses in van der Waals(vdW)crystals,offering new possibilities for controlling the flow of light at the nanoscale.However,these PhPs,including their directional propagation,are inherently determined by the anisotropic crystal structure of the host materials.Although in-plane anisotropic PhPs can be manipulated by twisting engineering,such as twisting individual vdW slabs,dynamically adjusting their propagation presents a significant challenge.The limited application of the twisted bilayer structure in bare films further restricts its usage.In this study,we present a technique in which anisotropic PhPs supported by bare biaxial vdW slabs can be actively tuned by modifying their local dielectric environment.Excitingly,we predict that the iso-frequency contour of PhPs can be reoriented to enable propagation along forbidden directions when the crystal is placed on a substrate with a moderate negative permittivity.Besides,we systematically investigate the impact of polaritonic coupling on near-field radiative heat transfer(NFRHT)between heterostructures integrated with different substrates that have negative permittivity.Our main findings reveal that through the analysis of dispersion contour and photon transmission coefficient,the excitation and reorientation of the fundamental mode facilitate increased photon tunneling,thereby enhancing heat transfer between heterostructures.Conversely,the annihilation of the fundamental mode hinders heat transfer.Furthermore,we find the enhancement or suppression of radiative energy transport depends on the relative magnitude of the slab thickness and the vacuum gap width.Finally,the effect of negative permittivity substrates on NFRHT along the[001]crystalline direction ofα-MoO3 is considered.The spectral band where the excited fundamental mode resulting from the negative permittivity substrates is shifted to the first Reststrahlen Band(RB 1)ofα-MoO_(3) and is widened,resulting in more significant enhancement of heat flux from RB 1.We anticipate our results will motivate new direction for dynamical tunability of the PhPs in photonic devices.
基金The research is supported by NSF of China (10371113 10471133)
文摘The main aim of this article is to study the approximation of a locking-free anisotropic nonconforming finite element for the pure displacement boundary value problem of planar linear elasticity. The optimal error estimates are obtained by using some novel approaches and techniques. The method proposed in this article is robust in the sense that the convergence estimates in the energy and L^2-norms are independent-of the Lame parameter λ.
基金This project was financially supported by the Research Grants Council(GRF Projects:16229216,16209917,16205517)the Innovation and Technology Commission(ITS/012/19)of Hong Kong SAR.
文摘Flexible multidirectional strain sensors are crucial to accurately determining the complex strain states involved in emerging sensing applications.Although considerable efforts have been made to construct anisotropic structures for improved selective sensing capabilities,existing anisotropic sensors suffer from a trade-off between high sensitivity and high stretchability with acceptable linearity.Here,an ultrasensitive,highly selective multidirectional sensor is developed by rational design of functionally different anisotropic layers.The bilayer sensor consists of an aligned carbon nanotube(CNT)array assembled on top of a periodically wrinkled and cracked CNT-graphene oxide film.The transversely aligned CNT layer bridge the underlying longitudinal microcracks to effectively discourage their propagation even when highly stretched,leading to superior sensitivity with a gauge factor of 287.6 across a broad linear working range of up to 100%strain.The wrinkles generated through a pre-straining/releasing routine in the direction transverse to CNT alignment is responsible for exceptional selectivity of 6.3,to the benefit of accurate detection of loading directions by the multidirectional sensor.This work proposes a unique approach to leveraging the inherent merits of two cross-influential anisotropic structures to resolve the trade-off among sensitivity,selectivity,and stretchability,demonstrating promising applications in full-range,multi-axis human motion detection for wearable electronics and smart robotics.
文摘The mechanism of the effects of anisotropic permeability on well patterns and reservoir development are investigated by coordinate transformation, fluid flow analysis, and reservoir development concepts. Anisotropy of permeability has reconstructive effects on well patterns. The originally designed flooding units are broken up, and new pattern units are made up of the wells that belong to different original units. The behavior possesses strong randomness, and leads to a complicated relationship among the injection and production wells, and unpredictable productivity of the formations. To prevent the break-up of well patterns, well lines should be either parallel or perpendicular to the maximum principal direction of the anisotropic permeability （i.e. the fracture direction）. To optimize the development effects ofanisotropic formations, the latitudinal and longitudinal well spacing of the well network are calculated from the principal values of the anisotropic permeability.
基金supported by the National Natural Science Foundation of China(11571039 and 11671185)supported by the National Natural Science Foundation of China(11471042)
文摘Let p∈（0, 1], q∈（0, ∞] and A be a general expansive matrix on Rn. Let HAp,q （Rn） be the anisotropic Hardy-Lorentz spaces associated with A defined via the non-tangential grand maximal function. In this article, the authors characterize HAp,q（Rn） in terms of the Lusin-area function, the Littlewood-Paley g-function or the Littlewood-Paley gλ＊-function via first establishing an anisotropic Fefferman-Stein vector-valued inequality in the Lorentz space Lp,q（Rn）. All these characterizations are new even for the classical isotropic Hardy-Lorentz spaces on Rn. Moreover, the range of λ in the gλ＊-function characterization of HAp,q （Rn） coincides with the best known one in the classical Hardy space Hp（Rn） or in the anisotropic Hardy space HAp （Rn）.
基金The National Natural Science Foundation of China(No.10474024)NSFC-RGC Joint Research Scheme(No.60318002)+1 种基金Youth Chenguang Project of Science and Technology of Wuhan City of China(No.20065004116-10)StateKey Lab.of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology,No.WUT2004 M08)
文摘The preparation process of electrically conductive filler for anisotropic conductive adhesive was performed and discussed.The spherical filler contains tri-layer structures: resin core,Ni-P intermediate coating layer,Au outer coating layer.The 4 μm resin spherical cores were synthesized by monodispersion polymerization method.Then they were contributed to electrical conductivity by electrolessly plating Ni-P layer and gold layer.These particles have good corrosion resistance,high stability,and enough mechanical strength.When mixed with thermosetting epoxy resin to produce anisotropic conductive adhesive(ACA),it can realize a good conductive bonding between bumps on dies and pads on substrates.This environmentally friendly conductive material offers numerous advantages over conventional solder technology and is an ideal substitute for the lead-contained solder in electronics packaging.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60741003 and 60871047)
文摘Analytical expressions of electric fields inside and outside an anisotropic dielectric sphere are presented by transforming an anisotropic medium into an isotropic one based on the multi-scale transformation of electromagnetic theory. The theoretical expressions are consistent with those in the literature. The inside electric field, the outside electric field and the angle between their directions are derived in detail. Numerical simulations show that the direction of the outside field influences the magnitude of the inside field, while the dielectric constant tensor greatly affects its direction.
