The interaction of the novel tetra-carboxylphenyl calix[4]arene （TCPC） with the bovine heart cytochrome c （Cc） was first investigated by fluorescence spectroscopy and molecular modeling methods. The formation of a...The interaction of the novel tetra-carboxylphenyl calix[4]arene （TCPC） with the bovine heart cytochrome c （Cc） was first investigated by fluorescence spectroscopy and molecular modeling methods. The formation of a stable 1：1 complex was monitored by fluorescence titration, and its binding constant is 1.916 ×10^7 L mol^-1. Molecular modeling reveals the recognition mechanism of TCPC to the Cc surface, that is, the electrostatic interaction drives TCPC to the Cc surface, and the van der Waals interaction orientates TCPC parallel to the cleft of Cc.展开更多
Small-section hydraulic tunnels are characterized by small spaces and various section forms,under complex environments,which makes it difficult to carry out an inspection by the mobile acquisition equipment.To resolve...Small-section hydraulic tunnels are characterized by small spaces and various section forms,under complex environments,which makes it difficult to carry out an inspection by the mobile acquisition equipment.To resolve these problems,an arbitrarily adjustable camera module deployment method and the corresponding automatic image acquisition equipment with multi-area array cameras are proposed and developed.Such method enables the acquisition of full-length surface images of the hydraulic tunnels with different cross-section forms and diameters by a one-way travel,and the overlap rate and accuracy of the acquired image sets meet the requirements of three-dimensional reconstruction and panoramic image generation.In addition,to improve the speed and accuracy of traditional algorithms for tunnel surface defects detection,this paper proposes an improved YOLOv5s-DECA model.The algorithm introduces DenseNet to optimize the backbone feature extraction network and incorporates an efficient channel attention ECA module to make a better extraction of features of defects.The experimental results show that mAP,and F1-score of YOLOv5-DECA are 73.4%and 74.6%,respectively,which are better than the common model in terms of accuracy and robustness.The proposed YOLOv5-DECA has great detection performance for targets with variable shapes and can solve the problem of classification imbalance in surface defects.Then,by combining YOLOv5-DECA with the direction search algorithm,a“point-ring-section”method is established to allow rapid identification of common surface defects by detecting them layer by layer with the bottom image of the stitched panorama as the seed.The presented method in this paper effectively solves the problem that a single image fails to show the overall distribution of the defects and their accurate positioning in a whole large tunnel section and the effective features of defects in an excessively large panoramic image size are difficult to be captured by the neural network.Field applications demonstrated that the presented method is adequate for high-precision and intelligent surface defect detection and positioning for different small-section hydraulic tunnels such as circular,arch-wall,and box-shaped hydraulic tunnels.展开更多
With the aid of different types of mechanoreceptors,human is capable of perceiving stimuli from surrounding environments and manipulating various objects dexterously.In this paper,a bio-inspired tactile fingertip is d...With the aid of different types of mechanoreceptors,human is capable of perceiving stimuli from surrounding environments and manipulating various objects dexterously.In this paper,a bio-inspired tactile fingertip is designed mimicking human fingertip in both structures and functionalities.Two pairs of strain gages and(Polyvinylidene Fluoride)PVDF films are perpendicularly arranged to simulate the Fast-Adapting(FA)and Slowly Adapting(SA)type mechanoreceptors in human hands,while silicones,Polymethyl Methacrylate(PMMA),and electronic wires are applied to mimic the skin,bone and nerve fibers.Both static and dynamic forces can be perceived sensitively.A preprocessing electric circuit is further designed to transform the resistor changes into voltages,and then filter and amplify the four-channel signals.In addition to strong robustness due to the embedded structure,the developed fingertip is found sensitive to deformations via a force test experiment.Finally,two robotic experiments explore its recognition ability of contact status and object surface.Excellent performance is found with high accuracy of 99.72%achieved in discriminating six surfaces that are ubiquitous in daily life,which demonstrates the effectiveness of our designed tactile sensor.展开更多
A novel method to extract conic blending feature in reverse engineering is presented. Different from the methods to recover constant and variable radius blends from unorganized points, it contains not only novel segme...A novel method to extract conic blending feature in reverse engineering is presented. Different from the methods to recover constant and variable radius blends from unorganized points, it contains not only novel segmentation and feature recognition techniques, but also bias corrected technique to capture more reliable distribution of feature parameters along the spine curve. The segmentation depending on point classification separates the points in the conic blend region from the input point cloud. The available feature parameters of the cross-sectional curves are extracted with the processes of slicing point clouds with planes, conic curve fitting, and parameters estimation and compensation, The extracted parameters and its distribution laws are refined according to statistic theory such as regression analysis and hypothesis test. The proposed method can accurately capture the original design intentions and conveniently guide the reverse modeling process. Application examples are presented to verify the high precision and stability of the proposed method.展开更多
基金supported by the National Natural Science Foundation of China (No.90813018)the Youth Foundation of Shanxi Province (No.2006021009)as well as the Youth Scientific and Technical Foundation of Shanxi University (Nos.2006007 and 2007112).
文摘The interaction of the novel tetra-carboxylphenyl calix[4]arene （TCPC） with the bovine heart cytochrome c （Cc） was first investigated by fluorescence spectroscopy and molecular modeling methods. The formation of a stable 1：1 complex was monitored by fluorescence titration, and its binding constant is 1.916 ×10^7 L mol^-1. Molecular modeling reveals the recognition mechanism of TCPC to the Cc surface, that is, the electrostatic interaction drives TCPC to the Cc surface, and the van der Waals interaction orientates TCPC parallel to the cleft of Cc.
基金funded by the Hunan Provincial Natural Science Foundation Project(Grant No.2023JJ30672)the Science and Technology Research and Development Program Project of China Railway Group Limited(Grant No.2021-Special-08(A))+1 种基金the Science and Technology Research and Development Plan Project of China National Railway Group Co.Ltd.(Grant No.L2022G003)the Open Foundation of National Engineering Laboratory for High-speed Railway Construction(No.HSR202005).
文摘Small-section hydraulic tunnels are characterized by small spaces and various section forms,under complex environments,which makes it difficult to carry out an inspection by the mobile acquisition equipment.To resolve these problems,an arbitrarily adjustable camera module deployment method and the corresponding automatic image acquisition equipment with multi-area array cameras are proposed and developed.Such method enables the acquisition of full-length surface images of the hydraulic tunnels with different cross-section forms and diameters by a one-way travel,and the overlap rate and accuracy of the acquired image sets meet the requirements of three-dimensional reconstruction and panoramic image generation.In addition,to improve the speed and accuracy of traditional algorithms for tunnel surface defects detection,this paper proposes an improved YOLOv5s-DECA model.The algorithm introduces DenseNet to optimize the backbone feature extraction network and incorporates an efficient channel attention ECA module to make a better extraction of features of defects.The experimental results show that mAP,and F1-score of YOLOv5-DECA are 73.4%and 74.6%,respectively,which are better than the common model in terms of accuracy and robustness.The proposed YOLOv5-DECA has great detection performance for targets with variable shapes and can solve the problem of classification imbalance in surface defects.Then,by combining YOLOv5-DECA with the direction search algorithm,a“point-ring-section”method is established to allow rapid identification of common surface defects by detecting them layer by layer with the bottom image of the stitched panorama as the seed.The presented method in this paper effectively solves the problem that a single image fails to show the overall distribution of the defects and their accurate positioning in a whole large tunnel section and the effective features of defects in an excessively large panoramic image size are difficult to be captured by the neural network.Field applications demonstrated that the presented method is adequate for high-precision and intelligent surface defect detection and positioning for different small-section hydraulic tunnels such as circular,arch-wall,and box-shaped hydraulic tunnels.
基金funded by National Natural Science Foundation of China under Grant No.52205009Natural Science Foundation of Jiangsu Province under Grant No.BK20210233Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems.
文摘With the aid of different types of mechanoreceptors,human is capable of perceiving stimuli from surrounding environments and manipulating various objects dexterously.In this paper,a bio-inspired tactile fingertip is designed mimicking human fingertip in both structures and functionalities.Two pairs of strain gages and(Polyvinylidene Fluoride)PVDF films are perpendicularly arranged to simulate the Fast-Adapting(FA)and Slowly Adapting(SA)type mechanoreceptors in human hands,while silicones,Polymethyl Methacrylate(PMMA),and electronic wires are applied to mimic the skin,bone and nerve fibers.Both static and dynamic forces can be perceived sensitively.A preprocessing electric circuit is further designed to transform the resistor changes into voltages,and then filter and amplify the four-channel signals.In addition to strong robustness due to the embedded structure,the developed fingertip is found sensitive to deformations via a force test experiment.Finally,two robotic experiments explore its recognition ability of contact status and object surface.Excellent performance is found with high accuracy of 99.72%achieved in discriminating six surfaces that are ubiquitous in daily life,which demonstrates the effectiveness of our designed tactile sensor.
基金This project is supported by General Electric Company and National Advanced Technology Project of China(No.863-511-942-018).
文摘A novel method to extract conic blending feature in reverse engineering is presented. Different from the methods to recover constant and variable radius blends from unorganized points, it contains not only novel segmentation and feature recognition techniques, but also bias corrected technique to capture more reliable distribution of feature parameters along the spine curve. The segmentation depending on point classification separates the points in the conic blend region from the input point cloud. The available feature parameters of the cross-sectional curves are extracted with the processes of slicing point clouds with planes, conic curve fitting, and parameters estimation and compensation, The extracted parameters and its distribution laws are refined according to statistic theory such as regression analysis and hypothesis test. The proposed method can accurately capture the original design intentions and conveniently guide the reverse modeling process. Application examples are presented to verify the high precision and stability of the proposed method.
