The spherical Ti particle(Ti_(p))reinforced Mg-5Zn-0.5Ca(Ti_(p)/ZX50)composite was prepared via the semisolid stirring casting process and the effects of Ti_(p)on the hot deformation and hot processing behavior of mat...The spherical Ti particle(Ti_(p))reinforced Mg-5Zn-0.5Ca(Ti_(p)/ZX50)composite was prepared via the semisolid stirring casting process and the effects of Ti_(p)on the hot deformation and hot processing behavior of matrix alloy were investigated through uniaxial hot compression testing.The results indicate that a particle deformation zone(PDZ)forms around the Ti_(p)with the deformation of the Ti_(p)/ZX50 composite,which is propitious to the dynamic recrystallization(DRX)of the matrix alloy.The range of the PDZ and the promoting effect of the Ti_(p)on DRXed nucleation are inversely related to the deformation degree of the Ti_(p).Moreover,the deformation of Ti_(p)alleviates the high stress in the matrix alloy during deformation,expanding the processing range and reducing the average deformation activation energy of the matrix alloy.Notably,the minimum processing temperature(493 K)of the Ti_(p)/ZX50 composite is significantly lower than that of hardened particle reinforced magnesium matrix composites.The hot deformation mechanism of the Ti_(p)/ZX50 composite is dislocation climb controlled by both lattice diffusion and pipe diffusion.展开更多
Birds have developed near-perfect structures and functionality over millions of years of natural evolution.To improve the efficiency of fixed-wing vehicles in different environments,researchers have developed deformab...Birds have developed near-perfect structures and functionality over millions of years of natural evolution.To improve the efficiency of fixed-wing vehicles in different environments,researchers have developed deformable wings inspired by the wing structures of birds.Shape Memory Alloy(SMA)is applied as a smart material to the deformable wing.Compared with other drive methods,SMA actuators have the advantages of high drive capacity and a simple structure for driving wing deformation.According to the shape memory effect,SMA actuators are classified as single-range and dual-range actuators.The wing structure designed for each SMA drive is unique.By comparing and analyzing the structures of airfoils,airfoils with similar drive forms and deformation structures are put together for review and discussion.The deformable wings are categorized into out-of-face deformation,in-face deformation,airfoil curvature deformation,and combined deformation with multiple degrees of freedom based on the structure and location of the wing that produces the deformation.An overview of the deformed wing is introduced by telling the bionic theory of seagulls.The principles of deformation of the wing,the mechanics of the SMA actuator mechanism,and the aerodynamic characteristics of the deformable wing are presented.The structure and working principle of SMA actuators for each type of deformable wing are explained in detail.Methods and approaches to study the deformability of deformable wings are analyzed and summarized.This work provides comprehensive insights and perspectives for future studies of SMA-driven deformable airfoils.展开更多
The early and precise identification of Alzheimer’s Disease(AD)continues to pose considerable clinical difficulty due to subtle structural alterations and overlapping symptoms across the disease phases.This study pre...The early and precise identification of Alzheimer’s Disease(AD)continues to pose considerable clinical difficulty due to subtle structural alterations and overlapping symptoms across the disease phases.This study presents a novel Deformable Attention Vision Transformer(DA-ViT)architecture that integrates deformable Multi-Head Self-Attention(MHSA)with a Multi-Layer Perceptron(MLP)block for efficient classification of Alzheimer’s disease(AD)using Magnetic resonance imaging(MRI)scans.In contrast to traditional vision transformers,our deformable MHSA module preferentially concentrates on spatially pertinent patches through learned offset predictions,markedly diminishing processing demands while improving localized feature representation.DA-ViT contains only 0.93 million parameters,making it exceptionally suitable for implementation in resource-limited settings.We evaluate the model using a class-imbalanced Alzheimer’s MRI dataset comprising 6400 images across four categories,achieving a test accuracy of 80.31%,a macro F1-score of 0.80,and an area under the receiver operating characteristic curve(AUC)of 1.00 for the Mild Demented category.Thorough ablation studies validate the ideal configuration of transformer depth,headcount,and embedding dimensions.Moreover,comparison research indicates that DA-ViT surpasses state-of-theart pre-trained Convolutional Neural Network(CNN)models in terms of accuracy and parameter efficiency.展开更多
This paper presents CW-HRNet,a high-resolution,lightweight crack segmentation network designed to address challenges in complex scenes with slender,deformable,and blurred crack structures.The model incorporates two ke...This paper presents CW-HRNet,a high-resolution,lightweight crack segmentation network designed to address challenges in complex scenes with slender,deformable,and blurred crack structures.The model incorporates two key modules:Constrained Deformable Convolution(CDC),which stabilizes geometric alignment by applying a tanh limiter and learnable scaling factor to the predicted offsets,and the Wavelet Frequency Enhancement Module(WFEM),which decomposes features using Haar wavelets to preserve low-frequency structures while enhancing high-frequency boundaries and textures.Evaluations on the CrackSeg9k benchmark demonstrate CW-HRNet’s superior performance,achieving 82.39%mIoU with only 7.49M parameters and 10.34 GFLOPs,outperforming HrSegNet-B48 by 1.83% in segmentation accuracy with minimal complexity overhead.The model also shows strong cross-dataset generalization,achieving 60.01%mIoU and 66.22%F1 on Asphalt3k without fine-tuning.These results highlight CW-HRNet’s favorable accuracyefficiency trade-off for real-world crack segmentation tasks.展开更多
Conventional deformable wheel systems in robots and other mechatronic systems face significant challenges in achieving miniaturization,intelligence,and integration.To address these issues,we propose a novel integrated...Conventional deformable wheel systems in robots and other mechatronic systems face significant challenges in achieving miniaturization,intelligence,and integration.To address these issues,we propose a novel integrated structural design method and four-dimensional printing strategy for deformable wheels capable of shaping among multiple programmable direct-driven deformation configurations.The load-bearing capacity of the printed wheel is strengthened by employing deformed components in various locations and actuated states.Additionally,a novel analytical design method is presented to determine the structure,actuation,and deformation parameters of each component under complex coupled deformation.Our findings reveal that the designed wheel can transform into three different configurations,exhibiting desired deformations of 12.5%in the radial direction and 19.6%in the axial direction.It also demonstrates robust deformation behavior and structural stability under multi-directional loads.By integrating a terrain sensing system,the designed wheel exhibits highly adaptive deformation capabilities on various terrains,showing great potential for exploring complex environments.展开更多
Self-propulsion of a deformable ellipse immersed in an unbounded inviscid fluid is discussed in order to explore the effect of the deformation and controlled rotation of the body coupled with the shift of its internal...Self-propulsion of a deformable ellipse immersed in an unbounded inviscid fluid is discussed in order to explore the effect of the deformation and controlled rotation of the body coupled with the shift of its internal mass on the self-motion.The ellipse is capable of symmetric deformation along the two orthogonal axes and endowed with some self-regulation ability via the shift and rotation of its internal mass.From the model,the appropriate velocity potential induced by the motion of the ellipse with the deformation in an otherwise undisturbed fluid is derived,and then the equations of motion are obtained by means of integrals of the unsteady fluid pressure.The equations are utilized to explore self-translational behaviors of the ellipse through the cyclic shift of its internal mass and deformation coupled with its own controllable rotation.Analysis and numerical results show that the ellipse can break the kinematic time-reversal symmetry by properly adjusting its own rotation to coordinate with the deformation and the cyclic shift of the inner mass to meet a forward criterion,and push itself to move persistently forward without a regression at zero system momentum,exhibiting some basic serpentine movements according as the ellipse performs complete revolutions or oscillates between two extreme yaw angles during its self-motion.展开更多
Shape prediction of deformable linear objects(DLO)plays critical roles in robotics,medical devices,aerospace,and manufacturing,especially in manipulating objects such as cables,wires,and fibers.Due to the inherent fle...Shape prediction of deformable linear objects(DLO)plays critical roles in robotics,medical devices,aerospace,and manufacturing,especially in manipulating objects such as cables,wires,and fibers.Due to the inherent flexibility of DLO and their complex deformation behaviors,such as bending and torsion,it is challenging to predict their dynamic characteristics accurately.Although the traditional physical modeling method can simulate the complex deformation behavior of DLO,the calculation cost is high and it is difficult to meet the demand of real-time prediction.In addition,the scarcity of data resources also limits the prediction accuracy of existing models.To solve these problems,a method of fiber shape prediction based on a physical information graph neural network(PIGNN)is proposed in this paper.This method cleverly combines the powerful expressive power of graph neural networks with the strict constraints of physical laws.Specifically,we learn the initial deformation model of the fiber through graph neural networks(GNN)to provide a good initial estimate for the model,which helps alleviate the problem of data resource scarcity.During the training process,we incorporate the physical prior knowledge of the dynamic deformation of the fiber optics into the loss function as a constraint,which is then fed back to the network model.This ensures that the shape of the fiber optics gradually approaches the true target shape,effectively solving the complex nonlinear behavior prediction problem of deformable linear objects.Experimental results demonstrate that,compared to traditional methods,the proposed method significantly reduces execution time and prediction error when handling the complex deformations of deformable fibers.This showcases its potential application value and superiority in fiber manipulation.展开更多
Magnesium matrix composites(MMCs)combine exceptional low density,high specific strength,and stiffness,positioning them as critical materials for aerospace,automotive,and electronics industries.This review highlights r...Magnesium matrix composites(MMCs)combine exceptional low density,high specific strength,and stiffness,positioning them as critical materials for aerospace,automotive,and electronics industries.This review highlights recent progress in the fabrication of Ti-Mg composites and analyzes the mechanisms behind their enhanced mechanical properties.A key focus is the interfacial deformation incompatibility between Ti and Mg phases,which generates strain gradients and promotes the accumulation of geometrically necessary dislocations(GNDs)at the interface.This process not only improves strain hardening and ductility but also reveals the need for advanced micromechanical models to capture the plastic behavior of both phases.The review critically examines the impact of different Mg matrix types(AZ,AM,VW series)and the role of interfacial product morphology and size on bonding and overall performance.Furthermore,Ti reinforcement endows the composites with superior wear resistance and thermal conductivity,indicating broad application potential.展开更多
The complex skin structure and insufficient intracellular entrapment limit the therapeutic effects of active substances,therefore appealing to a more effective transdermal drug delivery system design.Herein,a hyaluron...The complex skin structure and insufficient intracellular entrapment limit the therapeutic effects of active substances,therefore appealing to a more effective transdermal drug delivery system design.Herein,a hyaluronic acid(HA)modified steareth-2-based niosomes(HA-nio)with satisfactory deformability and targeting properties was designed for ergothioneine(EGT)(EGT@HA-nio)against ultraviolet(UV)-induced skin damage.The unique composition allows EGT@HA-nio to exhibit high mechanical softness,making it deformable to pass through the stratum corneum by the intercellular space without rupture.For further intracellular delivery,HA modification enables EGT to target human dermal cells(HDFs)with increased distribution in mitochondria without the restriction of specific EGT transporter-organic cation transporter1(OCTN-1).Benefiting from the above properties,an adequate amount of EGT in the active form was accumulated in the desired cellular sites,alleviating UV-radiation-induced reactive oxygen species(ROS)generation,inflammatory factor release,DNA damage,and mitochondrial dysfunction.The in vivo experimental results show that EGT@HA-nio could significantly decrease collagen degradation,restore epidermal thickness and morphology to healthy levels,and effectively prevent UV-induced skin damage.With the ability to penetrate biological barriers and deliver drugs,HA-nio may promote the development of inadequate drug penetration disease treatment including skin diseases,cancers,and bacterial infections.展开更多
A flexible and adaptable design method for the tooth crown is presented based on the direct manipulation of free-form deformation （FFD）. The correct shape of the tooth crown can be obtained by adding, modifying, and...A flexible and adaptable design method for the tooth crown is presented based on the direct manipulation of free-form deformation （FFD）. The correct shape of the tooth crown can be obtained by adding, modifying, and deleting constraint points or load points based on stretching and compressing operation. Finally, an example is given to illustrate the method to be efficient.展开更多
Health monitoring of structures and people requires the integration of sensors and devices on various 3D curvilinear,hierarchically structured,and even dynamically changing surfaces.Therefore,it is highly desirable to...Health monitoring of structures and people requires the integration of sensors and devices on various 3D curvilinear,hierarchically structured,and even dynamically changing surfaces.Therefore,it is highly desirable to explore conformal manufacturing techniques to fabricate and integrate soft deformable devices on complex 3D curvilinear surfaces.Although planar fabrication methods are not directly suitable to manufacture conformal devices on 3D curvilinear surfaces,they can be combined with stretchable structures and the use of transfer printing or assembly methods to enable the device integration on 3D surfaces.Combined with functional nanomaterials,various direct printing and writing methods have also been developed to fabricate conformal electronics on curved surfaces with intimate contact even over a large area.After a brief summary of the recent advancement of the recent conformal manufacturing techniques,we also discuss the challenges and potential opportunities for future development in this burgeoning field of conformal electronics on complex 3D surfaces.展开更多
Integrating deformable mirrors within the optical train of an adaptive telescope was one of the major innovations in astronomical observation technology,distinguished by its high optical throughput,reduced optical sur...Integrating deformable mirrors within the optical train of an adaptive telescope was one of the major innovations in astronomical observation technology,distinguished by its high optical throughput,reduced optical surfaces,and the incorporation of the deformable mirror.Typically,voice-coil actuators are used,which require additional position sensors,internal control electronics,and cooling systems,leading to a very complex structure.Piezoelectric deformable secondary mirror technologies were proposed to overcome these problems.Recently,a high-order piezoelectric deformable secondary mirror has been developed and installed on the 1.8-m telescope at Lijiang Observatory in China to make it an adaptive telescope.The system consists of a 241-actuator piezoelectric deformable secondary mirror,a 192-sub-aperture Shack-Hartmann wavefront sensor,and a multi-core-based real-time controller.The actuator spacing of the PDSM measures 19.3 mm,equivalent to approximately 12.6 cm when mapped onto the primary mirror,significantly less than the voicecoil-based adaptive telescopes such as LBT,Magellan and VLT.As a result,stellar images with Strehl ratios above 0.49 in the R band have been obtained.To our knowledge,these are the highest R band images captured by an adaptive telescope with deformable secondary mirrors.Here,we report the system description and on-sky performance of this adaptive telescope.展开更多
The soil plug phenomenon involving the rising of the surface soil inside the bucket chamber under the suction pressure and seepage forces was simulated and calculated by deformable discrete element method (DDEM) model...The soil plug phenomenon involving the rising of the surface soil inside the bucket chamber under the suction pressure and seepage forces was simulated and calculated by deformable discrete element method (DDEM) models. The seepage forces, the effective gravity of soil, the friction on the chamber wall and the suction inside the chamber are considered as the main external forces of DDEM specimen. Three typical types of soil (silty clay, silt and sand) in the Bohai Sea are set as the main environmental conditions in the formation process of soil plug. It is found that the heights of soil plug simulated by DDEM models are 161.85 mm in silty clay, 125.22 mm in silt and 167.56 mm in sand, which are close to model test results and higher than those estimated by discrete element method (DEM). DDEM is an effective method to estimate and predict the heights of soil plug before suction penetration of bucket foundations on site.展开更多
Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent year...Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent years,deformable catalysts for HER have made great progress and would become a research hotspot.The catalytic activities of deformable catalysts could be adjustable by the strain engineering and surface reconfiguration.The surface curvature of flexible catalytic materials is closely related to the electrocatalytic HER properties.Here,firstly,we systematically summarized self-adaptive catalytic performance of deformable catalysts and various micro–nanostructures evolution in catalytic HER process.Secondly,a series of strategies to design highly active catalysts based on the mechanical flexibility of lowdimensional nanomaterials were summarized.Last but not least,we presented the challenges and prospects of the study of flexible and deformable micro–nanostructures of electrocatalysts,which would further deepen the understanding of catalytic mechanisms of deformable HER catalyst.展开更多
One of the important characteristic of adaptive mirrors is the thermal stability of surface flatness. In this paper, the thermal stability from 13℃ to 25℃ of a 20-actuator bimorph deformable mirror is tested by a Sh...One of the important characteristic of adaptive mirrors is the thermal stability of surface flatness. In this paper, the thermal stability from 13℃ to 25℃ of a 20-actuator bimorph deformable mirror is tested by a Shack-Hartmann wavefront sensor. Experimental results show that, the surface P-V of bimorph increases nearly linearly with ambient temperature. The ratio is 0.11 μm/℃ and the major component of surface displacement is defocused, compared with which, astigmatism, coma and spherical aberration contribute very small. Besides, a finite element model is built up to analyse the influence of thickness, thermal expansion coefficient and Young＇s modulus of materials on thermal stability. Calculated results show that bimorph has the best thermal stability when the materials have the same thermal expansion coefficient. And when the thickness ratio of glass to PZT is 3 and Young＇s modulus ratio is approximately 0.4, the surface instability behaviour of the bimorph manifests itself most severely.展开更多
Accurate registration of chest radiographs plays an increasingly important role in medical applications.However, most current intensity-based registration methods rely on the assumption of intensity conservation that ...Accurate registration of chest radiographs plays an increasingly important role in medical applications.However, most current intensity-based registration methods rely on the assumption of intensity conservation that is not suitable for alignment of chest radiographs. In this study, we propose a novel algorithm to match chest radiographs, for which the conventional residual complexity(RC) is modified as the similarity measure and the cubic B-spline transformation is adopted for displacement estimation. The modified similarity measure is allowed to incorporate the neighborhood influence into variation of intensity in a justified manner of the weight, while the transformation is implemented with a registration framework of pyramid structure. The results show that the proposed algorithm is more accurate in registration of chest radiographs, compared with some widely used methods such as the sum-of-squared-differences(SSD), correlation coefficient(CC) and mutual information(MI)algorithms, as well as the conventional RC approaches.展开更多
We propose a slope-based decoupling algorithm to simultaneously control the dual deformable mirrors （DMs） in a woofer-tweeter adaptive optics system. This algorithm can directly use the woofer＇s response matrix mea...We propose a slope-based decoupling algorithm to simultaneously control the dual deformable mirrors （DMs） in a woofer-tweeter adaptive optics system. This algorithm can directly use the woofer＇s response matrix measured from a Shack-Hartmann wave-front sensor to construct a slope-based orthogonal basis, and then selectively distribute the large- amplitude low-order aberration to woofer DM and the remaining aberration to tweeter DM through the slope-based orthogonal basis. At the same moment, in order to avoid the two DMs generating opposite compensation, a constraint matrix used to reset tweeter control vector is convenient to be calculated with the slope-based orthogonal basis. Numeral simulation demonstrates that this algorithm has a good performance to control the adaptive optics system with dual DMs simultaneously. Compared with the typical decoupling algorithm, this algorithm can take full use of the compensation ability of woofer DM and release the stroke of tweeter DM to compensate high-order aberration. More importantly, it does not need to measure the accurate shape of tweeter＇s influence function and keeps better performance of restraining the coupling error with the continuous-dynamic aberration.展开更多
Soft pneumatic actuators have been widely used for implementing sophisticated and dexterous movements,due to numerous fascinating features compared with their rigid counterparts.Relatively speaking,modeling and analys...Soft pneumatic actuators have been widely used for implementing sophisticated and dexterous movements,due to numerous fascinating features compared with their rigid counterparts.Relatively speaking,modeling and analysis of an entire soft pneumatic actuator considering contact interaction between two adjacent air chambers is extremely rare,which is exactly what we are particularly interested in.Therefore,in order to establish an accurate mechanical model and analyze the overall configuration and stress distribution for the soft pneumatic actuator with large deflection,we consider the contact interaction of soft materials rather than hard materials,to produce an effective enhanced model for soft contact of a large deformable pneumatic actuator.In this article,a multiple-point contact approach is developed to circumvent the mutual penetration problem between adjacent air chambers of the soft actuator that occurs with the single-point contact approach employed in linear elastic rigid materials.In contrast to the previous simplified rod-based model that did not focus on contact interaction which was adopted to clarify the entire deformation of the actuator,the present model not only elaborates nonlinear large deformation and overall configuration variations,but also accurately delineates stress distribution law inside the chamber structure and the stress concentration phenomenon.By means of a corresponding static experiment,a comparison of the simulation results with experimental data validates the effectiveness and accuracy of this model employing a multiple-point contact approach.Excellent simulation of the actual bending deformation of the soft actuator is obtained,while mutual penetration is successfully circumvented,whereas the model with single-point contact cannot achieve those goals.Finally,as compared with the rod-based model,the results obtained using the proposed model are more consistent with experimental data,and simulation precision is improved.展开更多
A new method for iris recognition using a multi-matching system based on a simplified deformable model of the human iris was proposed. The method defined iris feature points and formed the feature space based on a wa...A new method for iris recognition using a multi-matching system based on a simplified deformable model of the human iris was proposed. The method defined iris feature points and formed the feature space based on a wavelet transform. In the matching stage it worked in a crude manner. Driven by a simplified deformable iris model, the crude matching was refined. By means of such multi-matching system, the task of iris recognition was accomplished. This process can preserve the elastic deformation between an input iris image and a template and improve precision for iris recognition. The experimental results indicate the va- lidity of this method.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52271109 and 52401162)Natural Science Foundation of Shanxi(Nos.202403021211064 and 202403011212003)the Major Special Plan for Science and Technology in Shanxi Province(No.202201050201012).
文摘The spherical Ti particle(Ti_(p))reinforced Mg-5Zn-0.5Ca(Ti_(p)/ZX50)composite was prepared via the semisolid stirring casting process and the effects of Ti_(p)on the hot deformation and hot processing behavior of matrix alloy were investigated through uniaxial hot compression testing.The results indicate that a particle deformation zone(PDZ)forms around the Ti_(p)with the deformation of the Ti_(p)/ZX50 composite,which is propitious to the dynamic recrystallization(DRX)of the matrix alloy.The range of the PDZ and the promoting effect of the Ti_(p)on DRXed nucleation are inversely related to the deformation degree of the Ti_(p).Moreover,the deformation of Ti_(p)alleviates the high stress in the matrix alloy during deformation,expanding the processing range and reducing the average deformation activation energy of the matrix alloy.Notably,the minimum processing temperature(493 K)of the Ti_(p)/ZX50 composite is significantly lower than that of hardened particle reinforced magnesium matrix composites.The hot deformation mechanism of the Ti_(p)/ZX50 composite is dislocation climb controlled by both lattice diffusion and pipe diffusion.
基金supported by the National Science Fund for Distinguished Young Scholars(No.52025053)National Natural Science Foundation of China(No.52305302)+1 种基金the Natural Science Foundation of Jilin Province(No.20220101216JC)the asterisk indicates the corresponding authors.
文摘Birds have developed near-perfect structures and functionality over millions of years of natural evolution.To improve the efficiency of fixed-wing vehicles in different environments,researchers have developed deformable wings inspired by the wing structures of birds.Shape Memory Alloy(SMA)is applied as a smart material to the deformable wing.Compared with other drive methods,SMA actuators have the advantages of high drive capacity and a simple structure for driving wing deformation.According to the shape memory effect,SMA actuators are classified as single-range and dual-range actuators.The wing structure designed for each SMA drive is unique.By comparing and analyzing the structures of airfoils,airfoils with similar drive forms and deformation structures are put together for review and discussion.The deformable wings are categorized into out-of-face deformation,in-face deformation,airfoil curvature deformation,and combined deformation with multiple degrees of freedom based on the structure and location of the wing that produces the deformation.An overview of the deformed wing is introduced by telling the bionic theory of seagulls.The principles of deformation of the wing,the mechanics of the SMA actuator mechanism,and the aerodynamic characteristics of the deformable wing are presented.The structure and working principle of SMA actuators for each type of deformable wing are explained in detail.Methods and approaches to study the deformability of deformable wings are analyzed and summarized.This work provides comprehensive insights and perspectives for future studies of SMA-driven deformable airfoils.
基金Prince Sattambin Abdulaziz University for funding this research work through the project number(PSAU/2025/R/1446).
文摘The early and precise identification of Alzheimer’s Disease(AD)continues to pose considerable clinical difficulty due to subtle structural alterations and overlapping symptoms across the disease phases.This study presents a novel Deformable Attention Vision Transformer(DA-ViT)architecture that integrates deformable Multi-Head Self-Attention(MHSA)with a Multi-Layer Perceptron(MLP)block for efficient classification of Alzheimer’s disease(AD)using Magnetic resonance imaging(MRI)scans.In contrast to traditional vision transformers,our deformable MHSA module preferentially concentrates on spatially pertinent patches through learned offset predictions,markedly diminishing processing demands while improving localized feature representation.DA-ViT contains only 0.93 million parameters,making it exceptionally suitable for implementation in resource-limited settings.We evaluate the model using a class-imbalanced Alzheimer’s MRI dataset comprising 6400 images across four categories,achieving a test accuracy of 80.31%,a macro F1-score of 0.80,and an area under the receiver operating characteristic curve(AUC)of 1.00 for the Mild Demented category.Thorough ablation studies validate the ideal configuration of transformer depth,headcount,and embedding dimensions.Moreover,comparison research indicates that DA-ViT surpasses state-of-theart pre-trained Convolutional Neural Network(CNN)models in terms of accuracy and parameter efficiency.
文摘This paper presents CW-HRNet,a high-resolution,lightweight crack segmentation network designed to address challenges in complex scenes with slender,deformable,and blurred crack structures.The model incorporates two key modules:Constrained Deformable Convolution(CDC),which stabilizes geometric alignment by applying a tanh limiter and learnable scaling factor to the predicted offsets,and the Wavelet Frequency Enhancement Module(WFEM),which decomposes features using Haar wavelets to preserve low-frequency structures while enhancing high-frequency boundaries and textures.Evaluations on the CrackSeg9k benchmark demonstrate CW-HRNet’s superior performance,achieving 82.39%mIoU with only 7.49M parameters and 10.34 GFLOPs,outperforming HrSegNet-B48 by 1.83% in segmentation accuracy with minimal complexity overhead.The model also shows strong cross-dataset generalization,achieving 60.01%mIoU and 66.22%F1 on Asphalt3k without fine-tuning.These results highlight CW-HRNet’s favorable accuracyefficiency trade-off for real-world crack segmentation tasks.
基金supported by the National Key Research and Development Program of China(Grant No 2022YFB4600102)the National Natural Science Foundation of China(Grant No.U23A20637 and Grant No 52275561)。
文摘Conventional deformable wheel systems in robots and other mechatronic systems face significant challenges in achieving miniaturization,intelligence,and integration.To address these issues,we propose a novel integrated structural design method and four-dimensional printing strategy for deformable wheels capable of shaping among multiple programmable direct-driven deformation configurations.The load-bearing capacity of the printed wheel is strengthened by employing deformed components in various locations and actuated states.Additionally,a novel analytical design method is presented to determine the structure,actuation,and deformation parameters of each component under complex coupled deformation.Our findings reveal that the designed wheel can transform into three different configurations,exhibiting desired deformations of 12.5%in the radial direction and 19.6%in the axial direction.It also demonstrates robust deformation behavior and structural stability under multi-directional loads.By integrating a terrain sensing system,the designed wheel exhibits highly adaptive deformation capabilities on various terrains,showing great potential for exploring complex environments.
基金supported by the National Natural Science Foundation of China(Grant No.11672182).
文摘Self-propulsion of a deformable ellipse immersed in an unbounded inviscid fluid is discussed in order to explore the effect of the deformation and controlled rotation of the body coupled with the shift of its internal mass on the self-motion.The ellipse is capable of symmetric deformation along the two orthogonal axes and endowed with some self-regulation ability via the shift and rotation of its internal mass.From the model,the appropriate velocity potential induced by the motion of the ellipse with the deformation in an otherwise undisturbed fluid is derived,and then the equations of motion are obtained by means of integrals of the unsteady fluid pressure.The equations are utilized to explore self-translational behaviors of the ellipse through the cyclic shift of its internal mass and deformation coupled with its own controllable rotation.Analysis and numerical results show that the ellipse can break the kinematic time-reversal symmetry by properly adjusting its own rotation to coordinate with the deformation and the cyclic shift of the inner mass to meet a forward criterion,and push itself to move persistently forward without a regression at zero system momentum,exhibiting some basic serpentine movements according as the ellipse performs complete revolutions or oscillates between two extreme yaw angles during its self-motion.
基金Supported by the Fundamental Research Funds for the Central Universities(Grant Nos.2232024Y-01,LZB2023001)DHU Distinguished Young Professor Program+1 种基金National Natural Science Foundation of China(Grant No.52275478)AI-Enhanced Research Program of Shanghai Municipal Education Commission(Grant No.SMEC-AI-DHUY-05)。
文摘Shape prediction of deformable linear objects(DLO)plays critical roles in robotics,medical devices,aerospace,and manufacturing,especially in manipulating objects such as cables,wires,and fibers.Due to the inherent flexibility of DLO and their complex deformation behaviors,such as bending and torsion,it is challenging to predict their dynamic characteristics accurately.Although the traditional physical modeling method can simulate the complex deformation behavior of DLO,the calculation cost is high and it is difficult to meet the demand of real-time prediction.In addition,the scarcity of data resources also limits the prediction accuracy of existing models.To solve these problems,a method of fiber shape prediction based on a physical information graph neural network(PIGNN)is proposed in this paper.This method cleverly combines the powerful expressive power of graph neural networks with the strict constraints of physical laws.Specifically,we learn the initial deformation model of the fiber through graph neural networks(GNN)to provide a good initial estimate for the model,which helps alleviate the problem of data resource scarcity.During the training process,we incorporate the physical prior knowledge of the dynamic deformation of the fiber optics into the loss function as a constraint,which is then fed back to the network model.This ensures that the shape of the fiber optics gradually approaches the true target shape,effectively solving the complex nonlinear behavior prediction problem of deformable linear objects.Experimental results demonstrate that,compared to traditional methods,the proposed method significantly reduces execution time and prediction error when handling the complex deformations of deformable fibers.This showcases its potential application value and superiority in fiber manipulation.
基金the financial support from the National Key R&D Program of China(No.2022YFB3708400)National Natural Science Foundation of China(No.52171133,52225101)Basic and Applied Basic Research Foundation of Guangdong(No.2020B0301030006)。
文摘Magnesium matrix composites(MMCs)combine exceptional low density,high specific strength,and stiffness,positioning them as critical materials for aerospace,automotive,and electronics industries.This review highlights recent progress in the fabrication of Ti-Mg composites and analyzes the mechanisms behind their enhanced mechanical properties.A key focus is the interfacial deformation incompatibility between Ti and Mg phases,which generates strain gradients and promotes the accumulation of geometrically necessary dislocations(GNDs)at the interface.This process not only improves strain hardening and ductility but also reveals the need for advanced micromechanical models to capture the plastic behavior of both phases.The review critically examines the impact of different Mg matrix types(AZ,AM,VW series)and the role of interfacial product morphology and size on bonding and overall performance.Furthermore,Ti reinforcement endows the composites with superior wear resistance and thermal conductivity,indicating broad application potential.
基金supported by the National Natural Science Foundation of China(No.82222066)the National Key Research and Development Program of China(No.2022YFC2304104)。
文摘The complex skin structure and insufficient intracellular entrapment limit the therapeutic effects of active substances,therefore appealing to a more effective transdermal drug delivery system design.Herein,a hyaluronic acid(HA)modified steareth-2-based niosomes(HA-nio)with satisfactory deformability and targeting properties was designed for ergothioneine(EGT)(EGT@HA-nio)against ultraviolet(UV)-induced skin damage.The unique composition allows EGT@HA-nio to exhibit high mechanical softness,making it deformable to pass through the stratum corneum by the intercellular space without rupture.For further intracellular delivery,HA modification enables EGT to target human dermal cells(HDFs)with increased distribution in mitochondria without the restriction of specific EGT transporter-organic cation transporter1(OCTN-1).Benefiting from the above properties,an adequate amount of EGT in the active form was accumulated in the desired cellular sites,alleviating UV-radiation-induced reactive oxygen species(ROS)generation,inflammatory factor release,DNA damage,and mitochondrial dysfunction.The in vivo experimental results show that EGT@HA-nio could significantly decrease collagen degradation,restore epidermal thickness and morphology to healthy levels,and effectively prevent UV-induced skin damage.With the ability to penetrate biological barriers and deliver drugs,HA-nio may promote the development of inadequate drug penetration disease treatment including skin diseases,cancers,and bacterial infections.
文摘A flexible and adaptable design method for the tooth crown is presented based on the direct manipulation of free-form deformation （FFD）. The correct shape of the tooth crown can be obtained by adding, modifying, and deleting constraint points or load points based on stretching and compressing operation. Finally, an example is given to illustrate the method to be efficient.
基金This research is supported by the National Science Foundation(Grant No.ECCS-1933072)the Doctoral New Investigator grant from the American Chemical Society Petro-leum Research Fund(59021-DNI7)the National Heart,Lung,And Blood Institute of the National Institutes of Health under Award Number R61HL154215,and Penn State University.
文摘Health monitoring of structures and people requires the integration of sensors and devices on various 3D curvilinear,hierarchically structured,and even dynamically changing surfaces.Therefore,it is highly desirable to explore conformal manufacturing techniques to fabricate and integrate soft deformable devices on complex 3D curvilinear surfaces.Although planar fabrication methods are not directly suitable to manufacture conformal devices on 3D curvilinear surfaces,they can be combined with stretchable structures and the use of transfer printing or assembly methods to enable the device integration on 3D surfaces.Combined with functional nanomaterials,various direct printing and writing methods have also been developed to fabricate conformal electronics on curved surfaces with intimate contact even over a large area.After a brief summary of the recent advancement of the recent conformal manufacturing techniques,we also discuss the challenges and potential opportunities for future development in this burgeoning field of conformal electronics on complex 3D surfaces.
基金funded by the National Natural Science Foundation of China(No.11733005,12173041,11727805)Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2020376)Frontier Research Fund of Institute of Optics and Electronics,Chinese Academy of Sciences(No.C21K002).
文摘Integrating deformable mirrors within the optical train of an adaptive telescope was one of the major innovations in astronomical observation technology,distinguished by its high optical throughput,reduced optical surfaces,and the incorporation of the deformable mirror.Typically,voice-coil actuators are used,which require additional position sensors,internal control electronics,and cooling systems,leading to a very complex structure.Piezoelectric deformable secondary mirror technologies were proposed to overcome these problems.Recently,a high-order piezoelectric deformable secondary mirror has been developed and installed on the 1.8-m telescope at Lijiang Observatory in China to make it an adaptive telescope.The system consists of a 241-actuator piezoelectric deformable secondary mirror,a 192-sub-aperture Shack-Hartmann wavefront sensor,and a multi-core-based real-time controller.The actuator spacing of the PDSM measures 19.3 mm,equivalent to approximately 12.6 cm when mapped onto the primary mirror,significantly less than the voicecoil-based adaptive telescopes such as LBT,Magellan and VLT.As a result,stellar images with Strehl ratios above 0.49 in the R band have been obtained.To our knowledge,these are the highest R band images captured by an adaptive telescope with deformable secondary mirrors.Here,we report the system description and on-sky performance of this adaptive telescope.
基金Supported by National Natural Science Foundation of China(50079016) .
文摘The soil plug phenomenon involving the rising of the surface soil inside the bucket chamber under the suction pressure and seepage forces was simulated and calculated by deformable discrete element method (DDEM) models. The seepage forces, the effective gravity of soil, the friction on the chamber wall and the suction inside the chamber are considered as the main external forces of DDEM specimen. Three typical types of soil (silty clay, silt and sand) in the Bohai Sea are set as the main environmental conditions in the formation process of soil plug. It is found that the heights of soil plug simulated by DDEM models are 161.85 mm in silty clay, 125.22 mm in silt and 167.56 mm in sand, which are close to model test results and higher than those estimated by discrete element method (DEM). DDEM is an effective method to estimate and predict the heights of soil plug before suction penetration of bucket foundations on site.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51902101 and 21875203)the Natural Science Foundation of Hunan Province(Nos.2021JJ40044 and 2023JJ50287)Natural Science Foundation of Jiangsu Province(No.BK20201381).
文摘Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent years,deformable catalysts for HER have made great progress and would become a research hotspot.The catalytic activities of deformable catalysts could be adjustable by the strain engineering and surface reconfiguration.The surface curvature of flexible catalytic materials is closely related to the electrocatalytic HER properties.Here,firstly,we systematically summarized self-adaptive catalytic performance of deformable catalysts and various micro–nanostructures evolution in catalytic HER process.Secondly,a series of strategies to design highly active catalysts based on the mechanical flexibility of lowdimensional nanomaterials were summarized.Last but not least,we presented the challenges and prospects of the study of flexible and deformable micro–nanostructures of electrocatalysts,which would further deepen the understanding of catalytic mechanisms of deformable HER catalyst.
基金supported by the Key Project of National Natural Science Foundation of China (Grant No 60438030)
文摘One of the important characteristic of adaptive mirrors is the thermal stability of surface flatness. In this paper, the thermal stability from 13℃ to 25℃ of a 20-actuator bimorph deformable mirror is tested by a Shack-Hartmann wavefront sensor. Experimental results show that, the surface P-V of bimorph increases nearly linearly with ambient temperature. The ratio is 0.11 μm/℃ and the major component of surface displacement is defocused, compared with which, astigmatism, coma and spherical aberration contribute very small. Besides, a finite element model is built up to analyse the influence of thickness, thermal expansion coefficient and Young＇s modulus of materials on thermal stability. Calculated results show that bimorph has the best thermal stability when the materials have the same thermal expansion coefficient. And when the thickness ratio of glass to PZT is 3 and Young＇s modulus ratio is approximately 0.4, the surface instability behaviour of the bimorph manifests itself most severely.
基金the Fundamental Research Funds for the Central Universities of China(No.30918011104)the National Natural Science Foundation of China(Nos.61501241 and 61571230)+3 种基金the Natural Science Foundation of Jiangsu Province(No.BK20150792)the Foundation of Shandong Provincial Key Laboratory of Digital Medicine and Computer assisted Surgery(No.SDKL-DMCAS-2018-04)the China Postdoctoral Science Foundation(No.2015M570450)the Visiting Scholar Foundation of Key Laboratory of Biorheological Science and Technology(Chongqing University)of Ministry of Education(No.CQKLBST-2018-011)
文摘Accurate registration of chest radiographs plays an increasingly important role in medical applications.However, most current intensity-based registration methods rely on the assumption of intensity conservation that is not suitable for alignment of chest radiographs. In this study, we propose a novel algorithm to match chest radiographs, for which the conventional residual complexity(RC) is modified as the similarity measure and the cubic B-spline transformation is adopted for displacement estimation. The modified similarity measure is allowed to incorporate the neighborhood influence into variation of intensity in a justified manner of the weight, while the transformation is implemented with a registration framework of pyramid structure. The results show that the proposed algorithm is more accurate in registration of chest radiographs, compared with some widely used methods such as the sum-of-squared-differences(SSD), correlation coefficient(CC) and mutual information(MI)algorithms, as well as the conventional RC approaches.
基金Project supported by the Key Scientific Equipment Development Project of China(Grant No.ZDYZ2013-2)the National High-Tech R&D Program of China(Grant Nos.G128201-G158201 and G128603-G158603)+2 种基金the Innovation Fund of Chinese Academy of Science(Grant No.CXJJ-16M208)the Youth Innovation Promotion Association of the Chinese Academy of Sciencesthe Outstanding Young Scientists,Chinese Academy of Sciences
文摘We propose a slope-based decoupling algorithm to simultaneously control the dual deformable mirrors （DMs） in a woofer-tweeter adaptive optics system. This algorithm can directly use the woofer＇s response matrix measured from a Shack-Hartmann wave-front sensor to construct a slope-based orthogonal basis, and then selectively distribute the large- amplitude low-order aberration to woofer DM and the remaining aberration to tweeter DM through the slope-based orthogonal basis. At the same moment, in order to avoid the two DMs generating opposite compensation, a constraint matrix used to reset tweeter control vector is convenient to be calculated with the slope-based orthogonal basis. Numeral simulation demonstrates that this algorithm has a good performance to control the adaptive optics system with dual DMs simultaneously. Compared with the typical decoupling algorithm, this algorithm can take full use of the compensation ability of woofer DM and release the stroke of tweeter DM to compensate high-order aberration. More importantly, it does not need to measure the accurate shape of tweeter＇s influence function and keeps better performance of restraining the coupling error with the continuous-dynamic aberration.
基金the National Natural Science Foundation of China(Grants 11772186 and 11272203).
文摘Soft pneumatic actuators have been widely used for implementing sophisticated and dexterous movements,due to numerous fascinating features compared with their rigid counterparts.Relatively speaking,modeling and analysis of an entire soft pneumatic actuator considering contact interaction between two adjacent air chambers is extremely rare,which is exactly what we are particularly interested in.Therefore,in order to establish an accurate mechanical model and analyze the overall configuration and stress distribution for the soft pneumatic actuator with large deflection,we consider the contact interaction of soft materials rather than hard materials,to produce an effective enhanced model for soft contact of a large deformable pneumatic actuator.In this article,a multiple-point contact approach is developed to circumvent the mutual penetration problem between adjacent air chambers of the soft actuator that occurs with the single-point contact approach employed in linear elastic rigid materials.In contrast to the previous simplified rod-based model that did not focus on contact interaction which was adopted to clarify the entire deformation of the actuator,the present model not only elaborates nonlinear large deformation and overall configuration variations,but also accurately delineates stress distribution law inside the chamber structure and the stress concentration phenomenon.By means of a corresponding static experiment,a comparison of the simulation results with experimental data validates the effectiveness and accuracy of this model employing a multiple-point contact approach.Excellent simulation of the actual bending deformation of the soft actuator is obtained,while mutual penetration is successfully circumvented,whereas the model with single-point contact cannot achieve those goals.Finally,as compared with the rod-based model,the results obtained using the proposed model are more consistent with experimental data,and simulation precision is improved.
文摘A new method for iris recognition using a multi-matching system based on a simplified deformable model of the human iris was proposed. The method defined iris feature points and formed the feature space based on a wavelet transform. In the matching stage it worked in a crude manner. Driven by a simplified deformable iris model, the crude matching was refined. By means of such multi-matching system, the task of iris recognition was accomplished. This process can preserve the elastic deformation between an input iris image and a template and improve precision for iris recognition. The experimental results indicate the va- lidity of this method.
