Conventional four-probe methods for measuring the resistance of Josephson junctions can damage superconducting thin films,making them unsuitable for frequency measurements of superconducting qubits.In this study,we pr...Conventional four-probe methods for measuring the resistance of Josephson junctions can damage superconducting thin films,making them unsuitable for frequency measurements of superconducting qubits.In this study,we present a custom probe station measurement system that employs the fritting contact technique to achieve in situ,non-destructive measurements of Josephson junction resistance.Our experimental results demonstrate that this method allows for accurate prediction of qubit frequency with an error margin of 17.2 MHz.Moreover,the fritting contact technique does not significantly affect qubit coherence time or the integrity of the superconducting film,confirming its non-destructive nature.This innovative approach provides a dependable foundation for frequency tuning and addressing frequency collision issues,thus supporting the advancement and practical deployment of superconducting quantum computing.展开更多
Longitudinal joint construction quality is critical to the life of flexible pavements.Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies.Improving the joint's quality thr...Longitudinal joint construction quality is critical to the life of flexible pavements.Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies.Improving the joint's quality through better compaction during construction can help achieve flexible pavements with longer service lives and less maintenance.Current quality control(QC)and quality assurance(QA)plans provide limited coverage.Consequently,the risk of missing areas with poor joint compaction is significant.A density profiling system(DPS)is a non-destructive alternative to conventional destructive evaluation methods.It can provide quick and continuous real-time coverage of the compaction during construction in dielectrics.The paper presents several case studies comparing various types of longitudinal joints and demonstrating the use of DPS to evaluate the joint's compaction quality.The paper shows that dielectric measurements can provide valuable insight into the ability of various construction techniques to achieve adequate levels of compaction at the longitudinal joint.The paper proposes a dielectric-based longitudinal joint quality index(LJQI)to evaluate the relative compaction of the joint during construction.It also shows that adopting DPS for assessing the compaction of longitudinal joints can minimize the risk of agencies accepting poorly constructed joints,identify locations of poor quality during construction,and achieve better-performing flexible pavements.展开更多
This article takes the actual construction project of a certain concrete bridge project as an example to analyze the application of acoustic non-destructive testing technology in its detection.It includes an overview ...This article takes the actual construction project of a certain concrete bridge project as an example to analyze the application of acoustic non-destructive testing technology in its detection.It includes an overview of a certain bridge construction project studied and acoustic non-destructive testing technology and the application of acoustic non-destructive testing technology in actual testing.This analysis hopes to provide some guidelines for acoustic non-destructive testing of modern concrete bridge projects.展开更多
动物实验是生物医学研究中的重要手段,是连接基础研究与临床试验的桥梁。动物实验的系统评价/Meta分析(systematic review/meta-analysis,SRs/MAs)是整合动物实验证据的重要手段,能够促进成果向临床研究转化,降低转化风险,并推动基础研...动物实验是生物医学研究中的重要手段,是连接基础研究与临床试验的桥梁。动物实验的系统评价/Meta分析(systematic review/meta-analysis,SRs/MAs)是整合动物实验证据的重要手段,能够促进成果向临床研究转化,降低转化风险,并推动基础研究的资源整合。随着证据推荐分级的评估、制订与评价(grading of recommendations assessment,development and evaluation,GRADE)方法的不断发展,其在动物实验SRs/MAs中的应用受到了越来越多的关注。本文首先阐述了GRADE方法在动物实验SRs/MAs中的应用原理及具体应用类型,包括定性描述的系统评价、Meta分析及网状Meta分析;接着深入分析了GRADE方法在实际应用中的误用情况,主要包括未正确进行证据体分级、证据体分级不当、误用于定性系统评价、升降级过程记录与结果不一致,以及误用于提供推荐意见;此外,还全面探讨了GRADE方法在动物实验SRs/MAs中的证据确信度升降级因素,包括偏倚风险、间接性、不一致性、不精确性和发表偏倚对证据降级的影响,以及大效应量和跨物种一致性对证据升级的作用;最后,针对上述问题提出了改进策略,包括进一步研究与优化GRADE方法在动物实验SRs/MAs中的应用细节、制定符合动物实验研究特点的SRs/MAs报告规范,以及加强研究人员在GRADE方法上的专业培训等。本文旨在通过提升动物实验SRs/MAs的证据质量,增强其在临床决策中的可靠性,促进动物实验研究成果更高效地转化为临床实践。展开更多
A novel elastic metamaterial is proposed with the aim of achieving lowfrequency broad bandgaps and bandgap regulation.The band structure of the proposed metamaterial is calculated based on the Floquet-Bloch theorem,an...A novel elastic metamaterial is proposed with the aim of achieving lowfrequency broad bandgaps and bandgap regulation.The band structure of the proposed metamaterial is calculated based on the Floquet-Bloch theorem,and the boundary modes of each bandgap are analyzed to understand the effects of each component of the unit cell on the bandgap formation.It is found that the metamaterials with a low elastic modulus of ligaments can generate flexural wave bandgaps below 300 Hz.Multi-frequency vibrations can be suppressed through the selective manipulation of bandgaps.The dual-graded design of metamaterials that can significantly improve the bandgap width is proposed based on parametric studies.A new way that can regulate the bandgap is revealed by studying the graded elastic modulus in the substrate.The results demonstrate that the nonlinear gradient of the elastic modulus in the substrate offers better bandgap performance.Based on these analyses,the proposed elastic metamaterials can pave the way for multi-frequency vibration control,low-frequency bandgap broadening,and bandgap tuning.展开更多
Aluminum alloys are widely used in industry due to their light weight.These alloys are generally exposed to abrasive wear,which diminishes their effective lifespan.The wear resistance of these alloys is enhanced by ad...Aluminum alloys are widely used in industry due to their light weight.These alloys are generally exposed to abrasive wear,which diminishes their effective lifespan.The wear resistance of these alloys is enhanced by adding various reinforcements,however,this enhancement comes at the cost of reduced fracture toughness.This paradox of increased wear resistance versus decreased fracture toughness in aluminum alloys can be resolved by using functionally graded materials (FGMs).This study focuses on the abrasive wear behavior of functional graded aluminum matrix composites reinforced with Al_(3)Ti particles.The wear properties of the composites were investigated by considering the characteristics of the composite such as matrix type and various composite zones,as well as the wear parameters such as abrasive particle diameter,load,sliding speed and distance.Taguchi method was used in the abrasive wear tests in order to get more reliable results in a timeefficient manner.Experiment recipes were created based on the L_(27)(3^(6)) orthogonal series.As a result of the study,it is observed that the wear resistance of the composites increases with an increase in Al_(3)Ti reinforcement content and hardness of the matrix.In addition,the size of abrasive particles and the applied load are significant factors affecting abrasive wear.展开更多
BACKGROUND Esophageal squamous cell carcinoma is a major histological subtype of esophageal cancer.Many molecular genetic changes are associated with its occurrence.Raman spectroscopy has become a new method for the e...BACKGROUND Esophageal squamous cell carcinoma is a major histological subtype of esophageal cancer.Many molecular genetic changes are associated with its occurrence.Raman spectroscopy has become a new method for the early diagnosis of tumors because it can reflect the structures of substances and their changes at the molecular level.AIM To detect alterations in Raman spectral information across different stages of esophageal neoplasia.METHODS Different grades of esophageal lesions were collected,and a total of 360 groups of Raman spectrum data were collected.A 1D-transformer network model was proposed to handle the task of classifying the spectral data of esophageal squamous cell carcinoma.In addition,a deep learning model was applied to visualize the Raman spectral data and interpret their molecular characteristics.RESULTS A comparison among Raman spectral data with different pathological grades and a visual analysis revealed that the Raman peaks with significant differences were concentrated mainly at 1095 cm^(-1)(DNA,symmetric PO,and stretching vibration),1132 cm^(-1)(cytochrome c),1171 cm^(-1)(acetoacetate),1216 cm^(-1)(amide III),and 1315 cm^(-1)(glycerol).A comparison among the training results of different models revealed that the 1Dtransformer network performed best.A 93.30%accuracy value,a 96.65%specificity value,a 93.30%sensitivity value,and a 93.17%F1 score were achieved.CONCLUSION Raman spectroscopy revealed significantly different waveforms for the different stages of esophageal neoplasia.The combination of Raman spectroscopy and deep learning methods could significantly improve the accuracy of classification.展开更多
Innovation in learning algorithms has made retinal vessel segmentation and automatic grading tech-niques crucial for clinical diagnosis and prevention of diabetic retinopathy.The traditional methods struggle with accu...Innovation in learning algorithms has made retinal vessel segmentation and automatic grading tech-niques crucial for clinical diagnosis and prevention of diabetic retinopathy.The traditional methods struggle with accuracy and reliability due to multi-scale variations in retinal blood vessels and the complex pathological relationship in fundus images associated with diabetic retinopathy.While the single-modal diabetic retinopathy grading network addresses class imbalance challenges and lesion representation in fundus image data,dual-modal diabetic retinopathy grading methods offer superior performance.However,the scarcity of dual-modal data and the lack of effective feature fusion methods limit their potential due to multi-scale variations.This paper addresses these issues by focusing on multi-scale retinal vessel segmentation,dual feature fusion,data augmentation,and attention-based grading.The proposed model aims to improve comprehensive segmentation for retinal images with varying vessel thicknesses.It employs a dual-branch parallel architecture that integrates a transformer encoder with a convolutional neural network encoder to extract local and global information for synergistic saliency learning.Besides that,the model uses residual structures and attention modules to extract critical lesions,enhancing the accuracy and reliability of diabetic retinopathy grading.To evaluate the efficacy of the proposed approach,this study compared it with other pre-trained publicly open models,ResNet152V2,ConvNext,Efficient Net,DenseNet,and Swin Transform,with the same developmental parameters.All models achieved approximately 85%accuracy with the same image preparation method.However,the proposed approach outperforms and optimizes existing models by achieving an accuracy of 99.17%,99.04%,and 99.24%,on Kaggle APTOS19,IDRiD,and EyePACS datasets,respectively.These results support the model’s utility in helping ophthalmologists diagnose diabetic retinopathy more rapidly and accurately.展开更多
It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass.Based on digital speckle correlation(DSCM),acoustic emission(AE)and ...It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass.Based on digital speckle correlation(DSCM),acoustic emission(AE)and electromagnetic radiation(EMR),uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry,natural and saturated water content,to explore the fracture propagation,failure precursor characteristics and damage response mechanism under the influence of water content effect.The results show that with the increase of water content,the peak stress and crack initiation stress decrease gradually,and the decreases are 15.28%-21.11%and 17.64%-23.04%,respectively.The peak strain and crack initiation strain increase gradually,and the increases are 19.85%-44.53%and 19.15%-41.94%,respectively.The precracked rock with different water content is mainly characterized by tensile failure at different loading stages.However,with the increase of water content,the proportion of shear cracks gradually increases,while acoustic emission events gradually decrease,the dissipative energy and energy storage limits of the rock under peak load gradually decrease,and the charge signal increases significantly,which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.展开更多
The three-phase-lag(TPL)heat conduction model is an accurate representation of the actual heat transfer process.It would be interesting to investigate how the TPL model affects the thermal fracture behavior when there...The three-phase-lag(TPL)heat conduction model is an accurate representation of the actual heat transfer process.It would be interesting to investigate how the TPL model affects the thermal fracture behavior when there are defects existing in the medium.This paper aims to analyze the thermoelastic responses of two collinear cracks within a functionally graded half-space under thermal loadings by means of the TPL model.The thermoelastic problem is transformed into a series of singular integral equations using the integral transformation methods.The transient temperature and stress intensity factors(SIFs)are obtained through the application of Chebyshev polynomials.The effects of crack spacing and non-homogeneous parameters on the transient thermoelastic responses are presented,and the results of the TPL model are compared with those of the Fourier model,Cattaneo and Vernotte(CV)model,and dual-phase-lag(DPL)model.It is shown that crack spacing and non-homogeneous parameters have important effects on the thermoelastic responses,and the fluctuation phenomenon under the TPL model is the most pronounced due to the existence of the thermal displacement lag term.展开更多
This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM)that conveys fluids and is equipped with a retaining clip,focusing on primary resonance and subcr...This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM)that conveys fluids and is equipped with a retaining clip,focusing on primary resonance and subcritical dynamics.The nonlinear governing equations for the FGM pipe are derived by the extended Hamilton's principle,and subsequently discretized through the application of the Galerkin method.The direct method of multi-scales is then used to solve the derived equations.A thorough analysis of various parameters,including the clip stiffness,the power-law index,the porosity,and the clip location,is conducted to gain a comprehensive understanding of the system's nonlinear dynamics.Through the analysis of the first natural frequency,the study highlights the influence of the flow velocity and the clip stiffness,while the comparisons with metallic pipes emphasize the role of FGM composition.The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index,offering valuable insights into the system's nonlinear resonant behavior.Furthermore,the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness,revealing nuanced effects on the system response and resonance characteristics.This comprehensive analysis enhances the understanding of nonlinear behaviors in FGM porous pipes with a retaining clip,providing key insights for practical engineering applications in system design and optimization.展开更多
Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis r...Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.展开更多
This paper proposes a novel three-directional functionally graded(3D FG)vibration energy harvesting model based on a bimorph pipe structure.A rectangular pipe has material properties that vary continuously along the a...This paper proposes a novel three-directional functionally graded(3D FG)vibration energy harvesting model based on a bimorph pipe structure.A rectangular pipe has material properties that vary continuously along the axial,width,and height directions,and a steady fluid flows inside the pipe.Two piezoelectric layers are attached to the upper and lower surfaces of the pipe,and are connected in series with a load resistance.The output electricity is predicted theoretically and validated by finite element(FE) simulation.The complex mechanisms regulating the energy harvesting performance are investigated,focusing particularly on the effects of 3D FG material(FGM) parameters,load resistance,fluid-structure interaction(FSI),and geometry.Numerical results indicate that among several material gradient parameters,the axial gradient index has the most significant impact.Increasing the axial and height gradient indices can markedly enhance the energy harvesting performance.The optimal resistances differ between the first two modes.Overall,the maximum power is generated at lower resistances.The FSI effect can also improve the energy harvesting performance;however,higher flow velocities may destabilize the system,causing failure of harvesting energy.This research is capable of providing new insights into the design of a pipe energy harvester in engineering applications.展开更多
This paper extends the one-dimensional(1D)nonlocal strain gradient integral model(NStraGIM)to the two-dimensional(2D)Kirchhoff axisymmetric nanoplates,based on nonlocal strain gradient integral relations formulated al...This paper extends the one-dimensional(1D)nonlocal strain gradient integral model(NStraGIM)to the two-dimensional(2D)Kirchhoff axisymmetric nanoplates,based on nonlocal strain gradient integral relations formulated along both the radial and circumferential directions.By transforming the proposed integral constitutive equations into the equivalent differential forms,complemented by the corresponding constitutive boundary conditions(CBCs),a well-posed mathematical formulation is established for analyzing the axisymmetric bending and buckling of annular/circular functionally graded(FG)sandwich nanoplates.The boundary conditions at the inner edge of a solid nanoplate are derived by L'H?spital's rule.The numerical solution is obtained by the generalized differential quadrature method(GDQM).The accuracy of the proposed model is validated through comparison with the data from the existing literature.A parameter study is conducted to demonstrate the effects of FG sandwich parameters,size parameters,and nonlocal gradient parameters.展开更多
Background: The low-grade fibromyxoid sarcoma (LGFMS) is an exceptionally uncommon sarcoma that primarily manifests in the extremities or trunk of young adults, presenting as painless lesions. The histological feature...Background: The low-grade fibromyxoid sarcoma (LGFMS) is an exceptionally uncommon sarcoma that primarily manifests in the extremities or trunk of young adults, presenting as painless lesions. The histological features of this tumor are benign, but it exhibits an exceptionally high rate of late recurrence and a significant potential for metastasis. Imaging examinations serve as a crucial method for detecting LGFMS, while the definitive diagnosis relies on histopathological assessment. Currently, the primary treatment modality for this neoplasm is surgical resection. Early aggressive surgery with negative margins is a critical factor in mitigating the risk of tumor recurrence and metastasis. The present study presented a case of LGFMS located in the right thigh. The patient underwent a mass resection procedure following an MRI examination. During the telephone follow-up one year post-surgery, despite the absence of an imaging review, the surgical site demonstrated satisfactory recovery with no reported abnormal symptoms. Case Presentation: The patient, a 31-year-old male, presented to our hospital for evaluation of an asymptomatic mass in his right thigh that was incidentally discovered 13 years ago. The MRI showed a well-defined mass measuring 8.2 cm × 6.8 cm × 9.6 cm in the right thigh. The tumor signals exhibit a mixed pattern, characterized by predominantly isointense and hypointense signals on T1-weighted imaging (T1WI), a central area of hyperintensity on T2-weighted imaging (T2WI), and peripheral circular enhancement observed on contrast-enhanced scans. The patient underwent surgical resection. Microscopically, the mass was composed of intricately interwoven fibrous matrix and a distinct mucoid region. The tumor cells exhibited a distinctive arrangement in a swirling or wheel-like pattern, with minimal variation in their karyotypic characteristics. The immunohistochemical examination revealed diffuse and intense MUC4 positivity in the tumor cells. The diagnosis of LGFMS was confirmed by post-operative histopathological examination. Conclusions: The LGFMS is an exceptionally uncommon mesenchymal tumor renowned for its benign histological manifestations and malignant behavior. It is crucial to provide a comprehensive summary of the research findings and thoroughly review the existing literature pertaining to this rare disease.展开更多
Phase aberration correction for medical ultrasound systems has attracted a great deal of attention. Since phased array techniques are now widely employed for industrial non-destructive testing （NDT） applications in ...Phase aberration correction for medical ultrasound systems has attracted a great deal of attention. Since phased array techniques are now widely employed for industrial non-destructive testing （NDT） applications in various fields, the problem of phase aberrations in the process of NDT testing is considered. The technique of cross-covariance for phase aberration correction is presented. The performance of the technique for phase aberration correction is tested by means of echo signals obtained in practical non-destructive testing experiment. The results show that the technique has the better accuracy of phase correction.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12034018 and 11625419).
文摘Conventional four-probe methods for measuring the resistance of Josephson junctions can damage superconducting thin films,making them unsuitable for frequency measurements of superconducting qubits.In this study,we present a custom probe station measurement system that employs the fritting contact technique to achieve in situ,non-destructive measurements of Josephson junction resistance.Our experimental results demonstrate that this method allows for accurate prediction of qubit frequency with an error margin of 17.2 MHz.Moreover,the fritting contact technique does not significantly affect qubit coherence time or the integrity of the superconducting film,confirming its non-destructive nature.This innovative approach provides a dependable foundation for frequency tuning and addressing frequency collision issues,thus supporting the advancement and practical deployment of superconducting quantum computing.
文摘Longitudinal joint construction quality is critical to the life of flexible pavements.Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies.Improving the joint's quality through better compaction during construction can help achieve flexible pavements with longer service lives and less maintenance.Current quality control(QC)and quality assurance(QA)plans provide limited coverage.Consequently,the risk of missing areas with poor joint compaction is significant.A density profiling system(DPS)is a non-destructive alternative to conventional destructive evaluation methods.It can provide quick and continuous real-time coverage of the compaction during construction in dielectrics.The paper presents several case studies comparing various types of longitudinal joints and demonstrating the use of DPS to evaluate the joint's compaction quality.The paper shows that dielectric measurements can provide valuable insight into the ability of various construction techniques to achieve adequate levels of compaction at the longitudinal joint.The paper proposes a dielectric-based longitudinal joint quality index(LJQI)to evaluate the relative compaction of the joint during construction.It also shows that adopting DPS for assessing the compaction of longitudinal joints can minimize the risk of agencies accepting poorly constructed joints,identify locations of poor quality during construction,and achieve better-performing flexible pavements.
文摘This article takes the actual construction project of a certain concrete bridge project as an example to analyze the application of acoustic non-destructive testing technology in its detection.It includes an overview of a certain bridge construction project studied and acoustic non-destructive testing technology and the application of acoustic non-destructive testing technology in actual testing.This analysis hopes to provide some guidelines for acoustic non-destructive testing of modern concrete bridge projects.
文摘动物实验是生物医学研究中的重要手段,是连接基础研究与临床试验的桥梁。动物实验的系统评价/Meta分析(systematic review/meta-analysis,SRs/MAs)是整合动物实验证据的重要手段,能够促进成果向临床研究转化,降低转化风险,并推动基础研究的资源整合。随着证据推荐分级的评估、制订与评价(grading of recommendations assessment,development and evaluation,GRADE)方法的不断发展,其在动物实验SRs/MAs中的应用受到了越来越多的关注。本文首先阐述了GRADE方法在动物实验SRs/MAs中的应用原理及具体应用类型,包括定性描述的系统评价、Meta分析及网状Meta分析;接着深入分析了GRADE方法在实际应用中的误用情况,主要包括未正确进行证据体分级、证据体分级不当、误用于定性系统评价、升降级过程记录与结果不一致,以及误用于提供推荐意见;此外,还全面探讨了GRADE方法在动物实验SRs/MAs中的证据确信度升降级因素,包括偏倚风险、间接性、不一致性、不精确性和发表偏倚对证据降级的影响,以及大效应量和跨物种一致性对证据升级的作用;最后,针对上述问题提出了改进策略,包括进一步研究与优化GRADE方法在动物实验SRs/MAs中的应用细节、制定符合动物实验研究特点的SRs/MAs报告规范,以及加强研究人员在GRADE方法上的专业培训等。本文旨在通过提升动物实验SRs/MAs的证据质量,增强其在临床决策中的可靠性,促进动物实验研究成果更高效地转化为临床实践。
基金Project supported by the National Natural Science Foundation of China(Nos.11872233,U2341231,and 12102245)。
文摘A novel elastic metamaterial is proposed with the aim of achieving lowfrequency broad bandgaps and bandgap regulation.The band structure of the proposed metamaterial is calculated based on the Floquet-Bloch theorem,and the boundary modes of each bandgap are analyzed to understand the effects of each component of the unit cell on the bandgap formation.It is found that the metamaterials with a low elastic modulus of ligaments can generate flexural wave bandgaps below 300 Hz.Multi-frequency vibrations can be suppressed through the selective manipulation of bandgaps.The dual-graded design of metamaterials that can significantly improve the bandgap width is proposed based on parametric studies.A new way that can regulate the bandgap is revealed by studying the graded elastic modulus in the substrate.The results demonstrate that the nonlinear gradient of the elastic modulus in the substrate offers better bandgap performance.Based on these analyses,the proposed elastic metamaterials can pave the way for multi-frequency vibration control,low-frequency bandgap broadening,and bandgap tuning.
基金financially supported by the Scientific Research Project Coordinatorship (BAP) of Yildiz Technical University (YTU) (Project No: FYL-2021-3825)。
文摘Aluminum alloys are widely used in industry due to their light weight.These alloys are generally exposed to abrasive wear,which diminishes their effective lifespan.The wear resistance of these alloys is enhanced by adding various reinforcements,however,this enhancement comes at the cost of reduced fracture toughness.This paradox of increased wear resistance versus decreased fracture toughness in aluminum alloys can be resolved by using functionally graded materials (FGMs).This study focuses on the abrasive wear behavior of functional graded aluminum matrix composites reinforced with Al_(3)Ti particles.The wear properties of the composites were investigated by considering the characteristics of the composite such as matrix type and various composite zones,as well as the wear parameters such as abrasive particle diameter,load,sliding speed and distance.Taguchi method was used in the abrasive wear tests in order to get more reliable results in a timeefficient manner.Experiment recipes were created based on the L_(27)(3^(6)) orthogonal series.As a result of the study,it is observed that the wear resistance of the composites increases with an increase in Al_(3)Ti reinforcement content and hardness of the matrix.In addition,the size of abrasive particles and the applied load are significant factors affecting abrasive wear.
基金Supported by Beijing Hospitals Authority Youth Programme,No.QML20200505.
文摘BACKGROUND Esophageal squamous cell carcinoma is a major histological subtype of esophageal cancer.Many molecular genetic changes are associated with its occurrence.Raman spectroscopy has become a new method for the early diagnosis of tumors because it can reflect the structures of substances and their changes at the molecular level.AIM To detect alterations in Raman spectral information across different stages of esophageal neoplasia.METHODS Different grades of esophageal lesions were collected,and a total of 360 groups of Raman spectrum data were collected.A 1D-transformer network model was proposed to handle the task of classifying the spectral data of esophageal squamous cell carcinoma.In addition,a deep learning model was applied to visualize the Raman spectral data and interpret their molecular characteristics.RESULTS A comparison among Raman spectral data with different pathological grades and a visual analysis revealed that the Raman peaks with significant differences were concentrated mainly at 1095 cm^(-1)(DNA,symmetric PO,and stretching vibration),1132 cm^(-1)(cytochrome c),1171 cm^(-1)(acetoacetate),1216 cm^(-1)(amide III),and 1315 cm^(-1)(glycerol).A comparison among the training results of different models revealed that the 1Dtransformer network performed best.A 93.30%accuracy value,a 96.65%specificity value,a 93.30%sensitivity value,and a 93.17%F1 score were achieved.CONCLUSION Raman spectroscopy revealed significantly different waveforms for the different stages of esophageal neoplasia.The combination of Raman spectroscopy and deep learning methods could significantly improve the accuracy of classification.
基金funded by Princess Nourah bint Abdulrahman University and Researchers Supporting Project number(PNURSP2025R346)Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia.
文摘Innovation in learning algorithms has made retinal vessel segmentation and automatic grading tech-niques crucial for clinical diagnosis and prevention of diabetic retinopathy.The traditional methods struggle with accuracy and reliability due to multi-scale variations in retinal blood vessels and the complex pathological relationship in fundus images associated with diabetic retinopathy.While the single-modal diabetic retinopathy grading network addresses class imbalance challenges and lesion representation in fundus image data,dual-modal diabetic retinopathy grading methods offer superior performance.However,the scarcity of dual-modal data and the lack of effective feature fusion methods limit their potential due to multi-scale variations.This paper addresses these issues by focusing on multi-scale retinal vessel segmentation,dual feature fusion,data augmentation,and attention-based grading.The proposed model aims to improve comprehensive segmentation for retinal images with varying vessel thicknesses.It employs a dual-branch parallel architecture that integrates a transformer encoder with a convolutional neural network encoder to extract local and global information for synergistic saliency learning.Besides that,the model uses residual structures and attention modules to extract critical lesions,enhancing the accuracy and reliability of diabetic retinopathy grading.To evaluate the efficacy of the proposed approach,this study compared it with other pre-trained publicly open models,ResNet152V2,ConvNext,Efficient Net,DenseNet,and Swin Transform,with the same developmental parameters.All models achieved approximately 85%accuracy with the same image preparation method.However,the proposed approach outperforms and optimizes existing models by achieving an accuracy of 99.17%,99.04%,and 99.24%,on Kaggle APTOS19,IDRiD,and EyePACS datasets,respectively.These results support the model’s utility in helping ophthalmologists diagnose diabetic retinopathy more rapidly and accurately.
基金financially supported by National Natural Science Foundation of China(No.52304136)Young Talent of Lifting Engineering for Science and Technology in Shandong,China(No.SDAST2024QTA060)Key Project of Research and Development in Liaocheng(No.2023YD02)。
文摘It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass.Based on digital speckle correlation(DSCM),acoustic emission(AE)and electromagnetic radiation(EMR),uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry,natural and saturated water content,to explore the fracture propagation,failure precursor characteristics and damage response mechanism under the influence of water content effect.The results show that with the increase of water content,the peak stress and crack initiation stress decrease gradually,and the decreases are 15.28%-21.11%and 17.64%-23.04%,respectively.The peak strain and crack initiation strain increase gradually,and the increases are 19.85%-44.53%and 19.15%-41.94%,respectively.The precracked rock with different water content is mainly characterized by tensile failure at different loading stages.However,with the increase of water content,the proportion of shear cracks gradually increases,while acoustic emission events gradually decrease,the dissipative energy and energy storage limits of the rock under peak load gradually decrease,and the charge signal increases significantly,which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.
基金Project supported by the Natural Science Foundation of Shandong Province of China(No.ZR2024MA085)the Science and Technology Plan Project of Zhejiang Province of China(No.2023C03143)the Fundamental Research Funds for the Central Universities of China。
文摘The three-phase-lag(TPL)heat conduction model is an accurate representation of the actual heat transfer process.It would be interesting to investigate how the TPL model affects the thermal fracture behavior when there are defects existing in the medium.This paper aims to analyze the thermoelastic responses of two collinear cracks within a functionally graded half-space under thermal loadings by means of the TPL model.The thermoelastic problem is transformed into a series of singular integral equations using the integral transformation methods.The transient temperature and stress intensity factors(SIFs)are obtained through the application of Chebyshev polynomials.The effects of crack spacing and non-homogeneous parameters on the transient thermoelastic responses are presented,and the results of the TPL model are compared with those of the Fourier model,Cattaneo and Vernotte(CV)model,and dual-phase-lag(DPL)model.It is shown that crack spacing and non-homogeneous parameters have important effects on the thermoelastic responses,and the fluctuation phenomenon under the TPL model is the most pronounced due to the existence of the thermal displacement lag term.
文摘This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM)that conveys fluids and is equipped with a retaining clip,focusing on primary resonance and subcritical dynamics.The nonlinear governing equations for the FGM pipe are derived by the extended Hamilton's principle,and subsequently discretized through the application of the Galerkin method.The direct method of multi-scales is then used to solve the derived equations.A thorough analysis of various parameters,including the clip stiffness,the power-law index,the porosity,and the clip location,is conducted to gain a comprehensive understanding of the system's nonlinear dynamics.Through the analysis of the first natural frequency,the study highlights the influence of the flow velocity and the clip stiffness,while the comparisons with metallic pipes emphasize the role of FGM composition.The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index,offering valuable insights into the system's nonlinear resonant behavior.Furthermore,the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness,revealing nuanced effects on the system response and resonance characteristics.This comprehensive analysis enhances the understanding of nonlinear behaviors in FGM porous pipes with a retaining clip,providing key insights for practical engineering applications in system design and optimization.
文摘Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.
基金Project supported by the National Natural Science Foundation of China (Nos. 12372025 and 12072311)。
文摘This paper proposes a novel three-directional functionally graded(3D FG)vibration energy harvesting model based on a bimorph pipe structure.A rectangular pipe has material properties that vary continuously along the axial,width,and height directions,and a steady fluid flows inside the pipe.Two piezoelectric layers are attached to the upper and lower surfaces of the pipe,and are connected in series with a load resistance.The output electricity is predicted theoretically and validated by finite element(FE) simulation.The complex mechanisms regulating the energy harvesting performance are investigated,focusing particularly on the effects of 3D FG material(FGM) parameters,load resistance,fluid-structure interaction(FSI),and geometry.Numerical results indicate that among several material gradient parameters,the axial gradient index has the most significant impact.Increasing the axial and height gradient indices can markedly enhance the energy harvesting performance.The optimal resistances differ between the first two modes.Overall,the maximum power is generated at lower resistances.The FSI effect can also improve the energy harvesting performance;however,higher flow velocities may destabilize the system,causing failure of harvesting energy.This research is capable of providing new insights into the design of a pipe energy harvester in engineering applications.
基金Project supported by the National Natural Science Foundation of China(No.12172169)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘This paper extends the one-dimensional(1D)nonlocal strain gradient integral model(NStraGIM)to the two-dimensional(2D)Kirchhoff axisymmetric nanoplates,based on nonlocal strain gradient integral relations formulated along both the radial and circumferential directions.By transforming the proposed integral constitutive equations into the equivalent differential forms,complemented by the corresponding constitutive boundary conditions(CBCs),a well-posed mathematical formulation is established for analyzing the axisymmetric bending and buckling of annular/circular functionally graded(FG)sandwich nanoplates.The boundary conditions at the inner edge of a solid nanoplate are derived by L'H?spital's rule.The numerical solution is obtained by the generalized differential quadrature method(GDQM).The accuracy of the proposed model is validated through comparison with the data from the existing literature.A parameter study is conducted to demonstrate the effects of FG sandwich parameters,size parameters,and nonlocal gradient parameters.
文摘Background: The low-grade fibromyxoid sarcoma (LGFMS) is an exceptionally uncommon sarcoma that primarily manifests in the extremities or trunk of young adults, presenting as painless lesions. The histological features of this tumor are benign, but it exhibits an exceptionally high rate of late recurrence and a significant potential for metastasis. Imaging examinations serve as a crucial method for detecting LGFMS, while the definitive diagnosis relies on histopathological assessment. Currently, the primary treatment modality for this neoplasm is surgical resection. Early aggressive surgery with negative margins is a critical factor in mitigating the risk of tumor recurrence and metastasis. The present study presented a case of LGFMS located in the right thigh. The patient underwent a mass resection procedure following an MRI examination. During the telephone follow-up one year post-surgery, despite the absence of an imaging review, the surgical site demonstrated satisfactory recovery with no reported abnormal symptoms. Case Presentation: The patient, a 31-year-old male, presented to our hospital for evaluation of an asymptomatic mass in his right thigh that was incidentally discovered 13 years ago. The MRI showed a well-defined mass measuring 8.2 cm × 6.8 cm × 9.6 cm in the right thigh. The tumor signals exhibit a mixed pattern, characterized by predominantly isointense and hypointense signals on T1-weighted imaging (T1WI), a central area of hyperintensity on T2-weighted imaging (T2WI), and peripheral circular enhancement observed on contrast-enhanced scans. The patient underwent surgical resection. Microscopically, the mass was composed of intricately interwoven fibrous matrix and a distinct mucoid region. The tumor cells exhibited a distinctive arrangement in a swirling or wheel-like pattern, with minimal variation in their karyotypic characteristics. The immunohistochemical examination revealed diffuse and intense MUC4 positivity in the tumor cells. The diagnosis of LGFMS was confirmed by post-operative histopathological examination. Conclusions: The LGFMS is an exceptionally uncommon mesenchymal tumor renowned for its benign histological manifestations and malignant behavior. It is crucial to provide a comprehensive summary of the research findings and thoroughly review the existing literature pertaining to this rare disease.
基金National Natural Science Foundation of China(No.61201412)Ntural Science Foundation of Shanxi Province(No.2012021011-5)
文摘Phase aberration correction for medical ultrasound systems has attracted a great deal of attention. Since phased array techniques are now widely employed for industrial non-destructive testing （NDT） applications in various fields, the problem of phase aberrations in the process of NDT testing is considered. The technique of cross-covariance for phase aberration correction is presented. The performance of the technique for phase aberration correction is tested by means of echo signals obtained in practical non-destructive testing experiment. The results show that the technique has the better accuracy of phase correction.
