A comprehensive understanding of exact seismic P-wave reflection and transmission(R/T)coefficients at imperfectly welded or non-welded contact interfaces holds paramount importance in the realm of seismic exploration....A comprehensive understanding of exact seismic P-wave reflection and transmission(R/T)coefficients at imperfectly welded or non-welded contact interfaces holds paramount importance in the realm of seismic exploration.Nonetheless,scant attention has been devoted in previous literature to the investigation of stress-dependent exact R/T coefficients in horizontal transversely isotropic(HTI)media,characterized by a horizontal symmetry axis,at such interfaces.Addressing this scholarly gap,we present exact R/T coefficient formulations specifically tailored to an imperfectly welded contact interface separating two HTI media under the influence of in-situ horizontal stress.We begin by deriving the equation of motion for a stressed HTI medium,utilizing the theoretical framework of acoustoelasticity to examine the impact of in-situ horizontal stress on the overarching elastic properties of HTI media.Precise boundary conditions are then established at the imperfectly welded contact interface by applying generalized stress-strain relationships and linear-slip theory,with the influence of in-situ horizontal stress on the interface further explored through the linear-slip model.By integrating these elements with the seismic wave displacement equation,we derive exact R/T coefficient formulations applicable to an imperfectly welded contact interface between two HTI media.Numerical analyses are conducted to elucidate the effects of in-situ horizontal stress on critical parameters such as rock density,seismic wave velocity,Thomsen-type anisotropy parameters,R/T coefficients,and seismic reflection responses at the imperfectly welded contact interface.Furthermore,the proposed formulations are frequency-dependent,with the imperfectly welded contact interface acting as a frequency-selective filter for both reflected and transmitted waves.Notably,under conditions of sufficiently large incident angles,the sensitivity of R/T coefficients to key influencing factors increases significantly.The derived R/T coefficient formulations and the accompanying numerical results offer valuable insights for fracture characterization,stress-dependent parameter inversion,and in-situ stress detection.展开更多
The study of ligand-receptor interactions is of great significance in food flavor perception.In this study,a computer simulation method was used to investigate the mechanism of interaction between umami peptides and T...The study of ligand-receptor interactions is of great significance in food flavor perception.In this study,a computer simulation method was used to investigate the mechanism of interaction between umami peptides and T1R1/T1R3-Venus-flytrap domain(VFT)receptor.The binding site,conformational changes,and binding free energy between umami peptides and T1R1/T1R3-VFT were analyzed through molecular modeling,molecular docking,and molecular dynamics simulations.The receptor model constructed using AlphaFold2 has the best rationality.The molecular docking results showed that umami peptides primarily bound to T1R1-VFT through hydrogen bonding,with key binding residues such as Thr149,Arg151,and Asp108.The binding of umami peptides led to a more stable complex system,and the positively charged amino acids contributed positively to the overall binding free energy.This study provides theoretical support for the development of a better understanding of the interaction between umami substances and the umami receptor.展开更多
针对发射/接收(T/R)组件中键合焊点的高效率准确检测需求,提出了一种结合外观特征和高维特征的无监督键合焊点质量检测方法。利用基于YOLOv8的键合焊点检测模型构建数据集,并采用霍夫圆变换(Hough circle transform,HCT)检测算法和视觉...针对发射/接收(T/R)组件中键合焊点的高效率准确检测需求,提出了一种结合外观特征和高维特征的无监督键合焊点质量检测方法。利用基于YOLOv8的键合焊点检测模型构建数据集,并采用霍夫圆变换(Hough circle transform,HCT)检测算法和视觉几何组(visual geometry group,VGG)卷积神经网络从焊点图像中提取了外观特征和高维特征。通过实验并结合实际情况设定了合理的阈值,构建了基于K-means算法的无监督键合焊点质量检测模型。测试结果表明,提出的检测方法取得了良好效果,有效解决了样本中严重的类别不平衡问题,为金丝键合焊点的质量控制提供了有效手段。展开更多
基金the sponsorship of the National Natural Science Foundation of China(42474172,42130810)the Science and Technology Innovation Program of Hunan Province(2022RC1238)+1 种基金the Natural Science Foundation of Hunan Province(2025JJ20036,2023JJ30663)the Changzhou Science and Technology Support Project(CE20235069)。
文摘A comprehensive understanding of exact seismic P-wave reflection and transmission(R/T)coefficients at imperfectly welded or non-welded contact interfaces holds paramount importance in the realm of seismic exploration.Nonetheless,scant attention has been devoted in previous literature to the investigation of stress-dependent exact R/T coefficients in horizontal transversely isotropic(HTI)media,characterized by a horizontal symmetry axis,at such interfaces.Addressing this scholarly gap,we present exact R/T coefficient formulations specifically tailored to an imperfectly welded contact interface separating two HTI media under the influence of in-situ horizontal stress.We begin by deriving the equation of motion for a stressed HTI medium,utilizing the theoretical framework of acoustoelasticity to examine the impact of in-situ horizontal stress on the overarching elastic properties of HTI media.Precise boundary conditions are then established at the imperfectly welded contact interface by applying generalized stress-strain relationships and linear-slip theory,with the influence of in-situ horizontal stress on the interface further explored through the linear-slip model.By integrating these elements with the seismic wave displacement equation,we derive exact R/T coefficient formulations applicable to an imperfectly welded contact interface between two HTI media.Numerical analyses are conducted to elucidate the effects of in-situ horizontal stress on critical parameters such as rock density,seismic wave velocity,Thomsen-type anisotropy parameters,R/T coefficients,and seismic reflection responses at the imperfectly welded contact interface.Furthermore,the proposed formulations are frequency-dependent,with the imperfectly welded contact interface acting as a frequency-selective filter for both reflected and transmitted waves.Notably,under conditions of sufficiently large incident angles,the sensitivity of R/T coefficients to key influencing factors increases significantly.The derived R/T coefficient formulations and the accompanying numerical results offer valuable insights for fracture characterization,stress-dependent parameter inversion,and in-situ stress detection.
基金funded by the National Natural Science Foundation of China(32001824,31972198)supported by the Startup Fund for Young Faculty at SJTU(Shanghai Jiao Tong University)High Level Innovation Team and Distinguished Scholar Project of Guangxi Universities and Colleges(2020[6]).
文摘The study of ligand-receptor interactions is of great significance in food flavor perception.In this study,a computer simulation method was used to investigate the mechanism of interaction between umami peptides and T1R1/T1R3-Venus-flytrap domain(VFT)receptor.The binding site,conformational changes,and binding free energy between umami peptides and T1R1/T1R3-VFT were analyzed through molecular modeling,molecular docking,and molecular dynamics simulations.The receptor model constructed using AlphaFold2 has the best rationality.The molecular docking results showed that umami peptides primarily bound to T1R1-VFT through hydrogen bonding,with key binding residues such as Thr149,Arg151,and Asp108.The binding of umami peptides led to a more stable complex system,and the positively charged amino acids contributed positively to the overall binding free energy.This study provides theoretical support for the development of a better understanding of the interaction between umami substances and the umami receptor.
文摘针对发射/接收(T/R)组件中键合焊点的高效率准确检测需求,提出了一种结合外观特征和高维特征的无监督键合焊点质量检测方法。利用基于YOLOv8的键合焊点检测模型构建数据集,并采用霍夫圆变换(Hough circle transform,HCT)检测算法和视觉几何组(visual geometry group,VGG)卷积神经网络从焊点图像中提取了外观特征和高维特征。通过实验并结合实际情况设定了合理的阈值,构建了基于K-means算法的无监督键合焊点质量检测模型。测试结果表明,提出的检测方法取得了良好效果,有效解决了样本中严重的类别不平衡问题,为金丝键合焊点的质量控制提供了有效手段。
