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Abstract Background Growth rate is a crucial economic trait for farmed animals, but the genetic regulation of this trait is largely unknown in non-model organisms such as shrimp. Results In this study, we performed genome-wide phenotypic quantitative trait loci (QTL) and expression quantitative trait loci (eQTL) mapping analyses to identify genes affecting the growth rate of Pacific white shrimp (Litopenaeus vannamei), which is the most commercially-farmed crustacean worldwide. We used RNA-sequencing of 268 individuals in a mapping population, and subsequently validated our findings through gene silencing and shrimp growth experiments. We constructed a high-density genetic linkage map comprising 5533 markers spanning 44 linkage groups, with a total distance of 6205.75 cM and an average marker interval of 1.12 cM. Our analyses identified 11 QTLs significantly correlated with growth rate, and 117,525 eQTLs. By integrating QTL and eQTL data, we identified a gene (metalloreductase STEAP4) highly associated with shrimp growth rate. RNA interference (RNAi) analysis and growth experiments confirmed that STEAP4 was significantly correlated with growth rate in L. vannamei. Conclusions Our results indicate that the comprehensive analysis of QTL and eQTL can effectively identify genes involved in complex animal traits. This is important for marker-assisted selection (MAS) of animals. Our work contributes to the development of shrimp breeding and available genetic resources.

Abstract Aircraft coating process has been an important part in manufacturing process of modern aviation products. For coating defect detection, the manual observation with naked eyes is usually utilized, which leads to low production efficiency. In this paper, the authors propose the improved YOLOv5‐OBB with the channel‐spatial attention block (CSAB), feature pyramid non‐local module (FPNM) and structured sparsity slimming criterion (SSSC). The CSAB can pay more attention to effective channel information features from the channel dimension and the target information area from the spatial dimension. The effective non‐local module called FPNM is proposed to further improve the detection accuracy. The authors utilize the oriented bounding boxes (OBB) to reduce redundant background information for coating defect detection. In addition, the SSSC is proposed to achieve network slimming and trade‐off between the efficiency and accuracy. The experimental results on several datasets demonstrate the effectiveness of the authors’ scheme, which achieves superior performance.

The aim of the study was to compare the effects and mechanism of tetrasodium pyrophosphate (TSPP) and sodium tripolyphosphate (STPP) as dispersants on the selective flotation of arsenopyrite from muscovite. The results of single-mineral flotation showed that the recovery of arsenopyrite was 81.4% when no dispersant was added. The recovery of arsenopyrite slightly decreased with increasing dosage of TSPP. When the dosage of STPP was 6 × 10−5 mol/L, the recovery of arsenopyrite was only 28.6%. Neither of the dispersants had significant influence on the muscovite flotation (

At present, the incidence of prostate cancer (PCa) in men is increasing year by year. So, the early diagnosis of PCa is of great significance. Transrectal ultrasonography (TRUS)-guided biopsy is a common method for diagnosing PCa. The biopsy process is performed manually by urologists but the diagnostic rate is only 20%–30% and its reliability and accuracy can no longer meet clinical needs. The image-guided prostate biopsy robot has the advantages of a high degree of automation, does not rely on the skills and experience of operators, reduces the work intensity and operation time of urologists and so on. Capable of delivering biopsy needles to pre-defined biopsy locations with minimal needle placement errors, it makes up for the shortcomings of traditional free-hand biopsy and improves the reliability and accuracy of biopsy. The integration of medical imaging technology and the robotic system is an important means for accurate tumor location, biopsy puncture path planning and visualization. This paper mainly reviews image-guided prostate biopsy robots. According to the existing literature, guidance modalities are divided into magnetic resonance imaging (MRI), ultrasound (US) and fusion image. First, the robot structure research by different guided methods is the main line and the actuators and material research of these guided modalities is the auxiliary line to introduce and compare. Second, the robot image-guided localization technology is discussed. Finally, the image-guided prostate biopsy robot is summarized and suggestions for future development are provided.

In the field of minimally invasive interventional therapy, the related research on the soft tissue puncture robot and its technology based on the flexible steerable needle as a research hot topic at present, and it has been developed rapidly in the past ten years. In order to better understand the development status of the flexible steerable needle puncture (FSNP) robot and provide reference for its design and improvement in subsequent research, it is necessary to introduce in two aspects of FSNP robot: the puncture path planning and the control methods. First, this article introduced the concept of the FSNP technology, and the necessity of the application of FSNP soft tissue robot in minimally invasive interventional surgery. Second, this article mainly introduced the principle of FSNP, the path planning of FSNP, the navigation and positioning control of the needle tip of the flexible steerable needle, the control method of FSNP system, and the controllable flexible needle. Finally, combined with the above analysis and introduction, it was pointed out that FSNP soft tissue robot and its related technology would be an important development direction in the field of minimally invasive interventional therapy in the future, and the current existing problems were pointed out. Meanwhile, the development trend of FSNP robot control technology was summarized and prospected.

The application of the stereoscopic parking robot makes it possible to relieve the pressure of urban traffic efficiently. With the aggravation of energy and environmental problems, the energy consumption of the stereoscopic parking robot is mainly concerned. In robot design, the kinematic performance reflects the motion transfer capability of the mechanism. A reasonable size of the mechanism can make energy transfer more efficient. This paper proposes a 2-DOF (Degree of Freedom) parallel lifting mechanism of the stereoscopic parking robot. Its branch contains double-constrained triangles that can perform symmetrical movements. Forward kinematics, inverse kinematics, workspace, and singular configuration are studied and analyzed. In this scheme, depending on the characteristics of the mechanism, the evaluation indices of motion consistency, workspace, and singularity performance are proposed. The energy-saving optimization design method based on the multiple kinematic performance indexes is used to find the optimum combination of structural parameters in the feasible region. Finally, the parallel lifting mechanism prototype is constructed, and the dynamic verification experiments are performed at driving speeds of 15.625, 12.5, and 10.42 mm/s. The results provide helpful guidance for the choice of driving speed to achieve optimal movement transfer capacity and stability of the mechanism. The multiple performance index design method can also be applied to other parallel mechanisms with low mobility, which require energy savings and steady motion.

Abstract Background The T-loop has been used clinically to close gap between teeth. And it is a typical orthodontic archwire bending method. However, the design of the T-loop parameters for different patients is based on the clinical experience of the dentists. The variation in dentists' clinical experience is the main reason for inadequate orthodontic treatment, even high incidence of postoperative complications. Methods Firstly, the tooth movement prediction model is established based on the analysis of the T-loop structure and the waxy model dynamic resistance. As well as the reverse reconstruction of the complete maxillary 3D model based on the patient CBCT images, the oral biomechanical FEM analysis is completed. A maxillary waxy dental model is manufactured to realize the water-bath measurement experiment in vitro mimicking the oral bio-environment. Thus, the calculated, simulation and experimental data are obtained, as well as obtaining a cloud of total deformation from the simulation analysis. Results The growth trend of the 11 sets of simulation data is the same as that of the experimental data. And all of them show that the tooth displacement is positively correlated with the cross-sectional size of the archwire, and the clearance distance. As well as the higher Young's modulus of the archwire material, the greater the tooth displacement. And the effect of archwire parameters on tooth displacement derived from simulation and experimental data is consistent with the prediction model. The experimental and calculated data are also compared and analyzed, and the two kinds of data are basically consistent in terms of growth trends and fluctuations, with deviation rates ranging from 2.17 to 10.00%. Conclusions This study shows that the accuracy and reliability of the tooth movement prediction model can be verified through the comparative analysis and deviation calculation of the obtained calculated, simulation and experimental data, which can assist dentists to safely and efficiently perform orthodontic treatment on patients. And the FEM analysis can achieve predictability of orthodontic treatment results.

In this paper we outline newly-developed control algorithms, designed to achieve high-precision feedback for a motor control system using a magnetic encoder. The magnetic encoder, combing single-pole and multi-pole magnetic steels, was adopted to extend the resolution of the magnetic encoder. First, with a view to settling the issue of the jump points of the multi-pole angle value at the convergence of two adjacent magnetic poles, the angle segmentation method, which uses the window filter discrimination method, is employed to determine the actual angle value. The appropriate filter window width is selected via the improved particle swarm optimization (IPSO) algorithm, and an expanded resolution is achieved. Second, a compensation table is completed via a linear compensation algorithm based on virtual cutting to enhance the accuracy of the combined magnetic encoder. On this basis, a linear difference algorithm is used to achieve deviation correction of the angle. Finally, the jump points can be restrained effectively via the angle segmentation method. The resolution reaches 0.05°, and the accuracy is 0.045°.

To enhance the sorption efficacy of attapulgite for heavy metals, mercapto-functionalized attapulgite (ATP-SH) was synthesized with mercaptan functional groups. When the mass-to-volume ratio of calcined attapulgite (ATP-C) to 3-Mercapropyltrimethoxysilane (MPTMS) was 1 g:0.5 mL (ATP-SH-0.5) and the pH was set to 8, a strong adsorption capacity for Cd (II) and Pb (II) was demonstrated. This indicates excellent adsorption performance for these heavy metals. ATP-SH-0.5 exhibited a maximum adsorption capacity of 43.81 mg/g and 274.83 mg/g for Cd (II) and Pb (II), respectively, in a single ion system. In a binary ion system, the maximum adsorption capacity was 31.86 mg/L and 254.45 mg/L for Cd (II) and Pb (II), respectively. Various characterizations and experiments showed that the adsorption of Cd (II) and Pb (II) onto ATP-SH-0.5 involves ion exchange reactions involving hydroxyl and thiol functional group complexation reactions. This adsorption process follows a single-molecule layer adsorption mechanism. XPS results indicate that hydroxyl and grafted thiol functional groups on the surface of mercapto-functionalized attapulgite participated in surface complexation reactions with Cd (II) and Pb (II), resulting in the formation of Cd-S and Pb-S species. Overall, this study provides a promising mercapto-functionalized modification material for the remediation of polluted water and soil.

In the paper, nonlinear vibration characteristics of a rotor system are investigated. Such a nonlinear rotor system is subjected to brush seal forces, which are obtained by integrating the bristle force along the entire ring. The nonlinear brush seal rotor system is constructed by merging a flexible rotor with nonlinear seal forces. The research is aimed at studying the nonlinear vibration characteristics and bifurcations of the motions under a variety of eccentricity circumstances. Different kinds of bifurcations are successfully obtained by mathematical discretization and mapping manipulation. Such a discrete mapping method successfully predicts the stable and unstable motions accurately. The period-doubling bifurcations and saddle node bifurcations of the rotor system are obtained. The sole unstable solutions are obtained, which are special, and a normal numerical integration method cannot solve this problem, which provides advantages in rotor design and motion control. According to the results, nonlinear resonances are found between the stable and unstable motions. The greater the eccentricity of the rotor, the greater the number of bifurcation points that occur during the rotor’s nonlinear motions, as well as the larger the ranges of speeds where the motions are unstable. Saddle node bifurcations generate unstable nonlinear motions and non-smooth motions, which may bring damage to the mechanical rotors. The period-doubling bifurcations produce the route from period-1 to period-2 motions in the nonlinear rotor system. The research provides a new perspective to study the bifurcations and stability of the nonlinear rotor systems.

In this paper, we are concerned with the following magnetic Schrödinger–Poisson system \begin{align*} \begin{cases} -(\nabla+i A(x))^{2}u+(\lambda V(x)+1)u+\phi u=\alpha f(\left | u\right |^{2})u+\vert u\vert^{4}u,& \text{ in }\mathbb{R}^{3}, \\ -\Delta \phi = u^{2}, & \text{ in } \mathbb{R}^{3}, \end{cases} \end{align*} where $\lambda>0$ is a parameter, $f$ is a subcritical nonlinearity, the potential $V:\mathbb{R}^{3}\rightarrow \mathbb{R}$ is a continuous function verifying some conditions, the magnetic potential $A \in L_{loc}^{2}(\mathbb{R}^{3}, \mathbb{R}^{3}) $. Assuming that the zero set of $V(x)$ has several isolated connected components $\Omega _{1},\dots,\Omega _{k}$ such that the interior of $\Omega _{j}$ is non-empty and $\partial \Omega_{j}$ is smooth, where $j\in \left \{1,\dots,k\right \}$, then for $\lambda>0$ large enough, we use the variational methods to show that the above system has at least $2^{k}-1$ multi-bump solutions.

Traditional methods for obtaining soil heavy metal content are expensive, inefficient, and limited in monitoring range. In order to meet the needs of soil environmental quality evaluation and health status assessment, visible near-infrared spectroscopy and XRF spectroscopy for monitoring heavy metal content in soil have attracted much attention, because of their rapid, nondestructive, economical, and environmentally friendly features. The use of either of these spectra alone cannot meet the accuracy requirements of traditional measurements, while the synergistic use of the two spectra can further improve the accuracy of monitoring heavy metal lead content in soil. Therefore, this study applied various spectral transformations and preprocessing to vis-NIR and XRF spectra; used the whale optimization algorithm (WOA) and competitive adaptive re-weighted sampling (CARS) algorithms to identify feature spectra; designed a combination variable model (CVM) based on multi-layer spectral data fusion, which improved the spectral preprocessing and spectral feature screening process to increase the efficiency of spectral fusion; and established a quantitative model for soil Pb concentration using partial least squares regression (PLSR). The estimation performance of three spectral fusion strategies, CVM, outer-product analysis (OPA), and Granger-Ramanathan averaging (GRA), was discussed. The results showed that the accuracy and efficiency of the CARS algorithm in the fused spectra estimation model were superior to those of the WOA algorithm, with an average coefficient of determination (R2) value of 0.9226 and an average root mean square error (RMSE) of 0.1984. The accuracy of the estimation models established, based on the different spectral types, to predict the Pb content of the soil was ranked as follows: the CVM model > the XRF spectral model > the vis-NIR spectral model. Within the CVM fusion strategy, the estimation model based on CARS and PLSR (CARS_D1+D2) performed the best, with R2 and RMSE values of 0.9546 and 0.2035, respectively. Among the three spectral fusion strategies, CVM had the highest accuracy, OPA had the smallest errors, and GRA showed a more balanced performance. This study provides technical means for on-site rapid estimation of Pb content based on multi-source spectral fusion and lays the foundation for subsequent research on dynamic, real-time, and large-scale quantitative monitoring of soil heavy metal pollution using high-spectral remote sensing images.

The bearing health in the traction motor is the prerequisite and guarantee for the safe operation of high-speed trains. The vibration signals of the bearing in traction motor feature high nonlinearity, non-stationarity, and background noise. Therefore, the features of the vibration signals are diverse and complex, making it hard to diagnose the faults of the bearing effectively and accurately. To overcome the difficulty, this paper puts forward a novel fault diagnosis method for the bearing of traction motor in high speed trains based on discrete wavelet transform (DWT) and improved deep belief network (DBN). Firstly, the vibration signals were extracted from various faulty bearings, and used to generate a two-dimensional (2D) time–frequency map. Then, the time–frequency map was preprocessed, and subjected to the deep learning (DL) by the improved DBN, aiming to identify the correlation between fault features and fault types. In this way, the fault state of the bearing in the traction motor was diagnosed and identified in a semi-supervised manner. To verify its effectiveness, the proposed method was applied to diagnose the bearing faults of traction motor in high-speed trains through comparative experiments. The results show that our method achieved better diagnosis accuracy than contrastive methods like backpropagation neural network (BPNN) and support vector machine (SVM).

This study focuses on using spodumene flotation tailings (SFT) to prepare phosphoric acid-activated metakaolin geopolymer, in which the replacement of metakaolin (MK) by a high percentage (up to 75 wt.%) of tailings was achieved. The compressive strength of geopolymer mortar was significantly improved with SFT as aggregates. In addition, the mechanical properties could also be enhanced by an increased concentration of phosphoric acid (H3PO4) solution or a decreased aggregate particle size. The optimized geopolymer mortar composite was SFT:MK = 3:1, which was activated by H3PO4 solution with a concentration of 51 vol%, followed by curing at 55 °C for 24 h. On the other hand, properties of the geopolymer mortar could also be affected by the morphology of the aggregates. For example, SFT as aggregates could produce more interconnected pores compared to standard sand. The major chemical structural units of geopolymer mortar were -P-O-Al- and AlPO4, which could be spontaneously generated according to the thermodynamic calculation results. Finally, many aluminum ions and a small amount of silicon ions could be leached from the tailings under acidic conditions.

Dental caries is a common disease affecting the health of humans. Tooth preparation is an essential method for the treatment of dental caries, and its effect determines the quality of dental caries restoration directly. At present, the doctor-patient ratio of dentistry is incredibly unbalanced, and it is challenging to meet the increasing demand for tooth preparation. Besides, it is prone to produce visual deviation and positioning error if the tooth preparation is operated manually by doctors. This paper focuses on the adjacent surface tooth preparation of the full crown. By analyzing the preparation process, the robot body as well as the end-effector are selected. Further, the pose and position between the robot and the tooth are established. Through the inverse calculation and interpolation of the NURBS curve, the robot-assisted trajectory planning of adjacent surface tooth preparation is realized. On the basis of the traditional offline programming method, mobile App “Dental Preparation Assisting Software” is developed based on augmented reality, which can interactively display the planned adjacent preparation curves and preparation information. And the robot can be controlled by the mobile App, which improves the visualization and efficiency of the preparation process. Finally, the experimental system based on the Dobot Magician robot is established, and the robot experiments of adjacent surface tooth preparation are carried out. The maximum relative fixed-point error of each feature point in the XYZ axis is 0.24 mm, 0.29 mm and 0.37 mm, respectively. The confidence interval width of each feature point in the XYZ direction is stable at about 0.31 mm on average, and the correlation between the feature points in the three directional variables is not strong. The proposed method of robot-assisted trajectory planning based on augmented reality for adjacent surface tooth preparation can improve the efficiency of tooth preparation and relieve the pressure of manual tooth preparation within the margin of error, and its feasibility and validity are verified.

Precise regulation of angiogenesis is required for organ development, wound repair, and tumor progression. Here, we identified a novel gene, nxhl (New XingHuo light), that is conserved in vertebrates and that plays a crucial role in vascular integrity and angiogenesis. Bioinformatic analysis uncovered its essential roles in development based on co-expression with several key developmental genes. Knockdown of nxhl in zebrafish causes global and pericardial edema, loss of blood circulation, and vascular defects characterized by both reduced vascularization in intersegmental vessels and decreased sprouting in the caudal vein plexus. The nxhl gene also affects human endothelial cell behavior in vitro. We found that nxhl functions in part by targeting VE-PTP through interaction with NCL (nucleolin). Loss of ptprb (a VE-PTP ortholo) in zebrafish resulted in defects similar to nxhl knockdown. Moreover, nxhl deficiency attenuates tumor invasion and proteins (including VE-PTP and NCL) associated with angiogenesis and EMT. These findings illustrate that nxhl can regulate angiogenesis via a novel nxhl–NCL–VE-PTP axis, providing a new therapeutic target for modulating vascular formation and function, especially for cancer treatment.

The thermal deformation of high-speed motorized spindle will affect its reliability, so fully considering its thermal characteristics is the premise of optimal design. In order to study the thermal characteristics of high-speed motorized spindles, a coupled model of thermal-flow-structure was established. Through experiment and simulation, the thermal characteristics of spiral cooling motorized spindle are studied, and the U-shaped cooled motorized spindle is designed and optimized. The simulation results show that when the diameter of the cooling channel is 7 mm, the temperature of the spiral cooling system is lower than that of the U-shaped cooling system, but the radial thermal deformation is greater than that of the U-shaped cooling system. As the increase of the channel diameter of U-shaped cooling system, the temperature and radial thermal deformation decrease. When the diameter is 10 mm, the temperature and radial thermal deformation are lower than the spiral cooling system. And as the flow rate increases, the temperature and radial thermal deformation gradually decrease, which provides a basis for a reasonable choice of water flow rate. The maximum error between experiment and simulation is 2°C, and the error is small, which verifies the accuracy and lays the foundation for future research.

Precise regulation of angiogenesis is required for organ development, wound repair, and tumor progression. Here, we identified a novel gene, nxhl (New XingHuo light), that is conserved in vertebrates and that plays a crucial role in vascular integrity and angiogenesis. Bioinformatic analysis uncovered its essential roles in development based on co-expression with several key developmental genes. Knockdown of nxhl in zebrafish causes global and pericardial edema, loss of blood circulation, and vascular defects characterized by both reduced vascularization in intersegmental vessels and decreased sprouting in the caudal vein plexus. The nxhl gene also affects human endothelial cell behavior in vitro. We found that nxhl functions in part by targeting VE-PTP through interaction with NCL (nucleolin). Loss of ptprb (a VE-PTP ortholo) in zebrafish resulted in defects similar to nxhl knockdown. Moreover, nxhl deficiency attenuates tumor invasion and proteins (including VE-PTP and NCL) associated with angiogenesis and EMT. These findings illustrate that nxhl can regulate angiogenesis via a novel nxhl-NCL-VE-PTP axis, providing a new therapeutic target for modulating vascular formation and function, especially for cancer treatment. [ABSTRACT FROM AUTHOR]

Breast cancer is one of the most frequent cancers and a major cause of cancer death in women. In this article, the design and control of a novel magnetic resonance imaging-compatible breast intervention robot are proposed. The dimensions and tolerance of the robot system are considered, and a novel pitching mechanism is designed to achieve a dexterous operation in the limited space. The magnetic resonance imaging compatibility of the robot materials is tested. The nonmagnetic structure and compact Cartesian mechanism of the robot allow it to operate safely in a magnetic resonance imaging scanner. According to the robot’s structure, a kinematics analysis based on a coupled motions model is established. The workspace simulation analysis of the robot proves that it is suitable for the whole breast surgery. To control the needle insertion tasks, the overall control system in the form of “personal computer (PC) + single-chip micyoco (SCM)” is designed. Finally, the motion control experiment is carried out, and the robot positioning error is 0.37 mm, which proves that the breast intervention robot and its control system designed in this article can meet the requirements of breast intervention.

Cancer represents a major threat to human health. Magnetic resonance imaging (MRI) provides superior performance to other imaging-based examination methods in the detection of tumors and offers distinct advantages in biopsy and seed implantation. However, because of the MRI environment, the material requirements for actuating devices for the medical robots used in MRI are incredibly demanding. This paper describes a novel double tendon-sheath transmission device for use in MRI applications. LeBus grooves are used in the original transmission wheels, thus enabling the system to realize long-distance and large-stroke transmission with improved accuracy. The friction model of the transmission system and the transmission characteristics model of the novel tendon-sheath structure are then established. To address the problem that tension sensors cannot be installed in large-stroke transmission systems, a three-point force measurement method is used to measure and set an appropriate preload in the novel tendon-sheath transmission system. Additionally, experiments are conducted to verify the accuracy of the theoretical model and multiple groups of tests are performed to explore the transmission characteristics. Finally, the novel tendon-sheath transmission system is compensated to improve its accuracy and the experimental results acquired after compensation show that the system satisfies the design requirements.

Introduction. Magnetic Resonance Imaging has better resolution for soft tissue; at the same time, the robot can work in a stable manner for a long time. MRI image-guided breast interventional robots have attracted much attention due to their minimally invasive nature and accuracy. In this paper, a hydraulic-driven MRI-compatible breast interventional robot is proposed to perform breast interventional procedure. Methods. First is the analysis of the design requirements of the hydraulic-driven MRI-compatible breast interventional robot, and then the design scheme is determined. Second, the three-dimensional model and the link frames are established. The workspace of the robot end point is solved by MATLAB/Simulink software. Then, the 3D printing technology is used to make a physical model of the MRI-compatible breast interventional robot. After assembly and debugging, the physical model is used for workspace verification, and the simulation result of the workspace shows that it is correct. Finally, the experimental research on the positioning error of the hydraulic drive is carried out, which established the theoretical foundation for the follow-up control research of the robot. Results. The positioning error has nothing to do with the motion distance, speed, and length of the selected tubing. The errors are 0.564 mm, 0.534 mm, and 0.533 mm at different distances of 40 mm, 80 mm, and 120 mm, respectively. The errors are 0.552 mm, 0.564 mm, and 0.559 mm at different speeds of 3 mm/s, 5 mm/s, and 8 mm/s, respectively. The errors are 0.564 mm, 0.568 mm, and 0.548 mm for different lengths of 0.5 m, 1 m, and 1.6 m, respectively. Then, the robot’s working space on the XOZ plane and the XOY plane meets the conditions. Conclusion. The structure of a differential rotary breast interventional robot is determined, with the link frames assigned to the mechanism and the Denavit-Hartenberg parameters given. Workspace simulation of MRI-compatible breast interventional robot is done in MATLAB. The 3D printed MRI-compatible breast interventional robot is assembled and debugged to verify that its working space and positioning error meet the requirements.

The 3D printing process lacks real-time inspection, which is still an open-loop manufacturing process, and the molding accuracy is low. Based on the 3D reconstruction theory of machine vision, in order to meet the applicability requirements of 3D printing process detection, a matching fusion method is proposed. The fast nearest neighbor (FNN) method is used to search matching point pairs. The matching point information of FFT-SIFT algorithm based on fast Fourier transform is superimposed with the matching point information of AKAZE algorithm, and then fused to obtain more dense feature point matching information and rich edge feature information. Combining incremental SFM algorithm with global SFM algorithm, an integrated SFM sparse point cloud reconstruction method is developed. The dense point cloud is reconstructed by PMVs algorithm, the point cloud model is meshed by Delaunay triangulation, and then the accurate 3D reconstruction model is obtained by texture mapping. The experimental results show that compared with the classical SIFT algorithm, the speed of feature extraction is increased by 25.0%, the number of feature matching is increased by 72%, and the relative error of 3D reconstruction results is about 0.014%, which is close to the theoretical error.

The robotic archwire bending technology has been used clinically to free orthodontic doctors from the heavy labor because of the improvement of the digital medical technology, and the digital expression of orthodontic archwire is necessary to realize the robotic archwire bending. Because of the differences between the human tooth arrangement and the difficulty of archwire shape design, it is difficult to realize the digital expression of orthodontic archwire. A method for the digital expression and interactive adjustment of personalized orthodontic archwire is presented in this paper. The straight section and the transitional section of the brackets are defined according to the reference points of the brackets. The transitional sections of the brackets are built by the mathematical model of Cubic Bezier curve. The process of handmade archwire bending, the method of discretization and combination are considered in the establishment of the mathematical model and model library about special function arch curve. The ways of the adjustment of the straight sections, the deformation of the transitional section shape, the selections of the position and type of special function arch curve are used in the study of the method for the digital expression and interactive adjustment of personalized orthodontic archwire. The interactive adjustment software is designed by the LABVIEW software. The archwire bending experiment is carried out, the error rate of the bent archwire ranged between 1.1% and 6.7% which proves the digital expression and interactive adjustment method of personalized orthodontic archwire for robotic bending is feasible and effective.

Proton heavy ion radiotherapy is widely used and currently represents the most advanced radiotherapy technology. However, at present, proton heavy ion radiotherapy chairs in fixed beam radiotherapy rooms do not have a head and neck positioning function. This paper presents a novel design for a proton heavy ion radiotherapy chair with a head and neck positioning device. The design of the posture adjustment mechanism and the head and neck positioning device of the treatment chair is based on U-TRIZ theory and ergonomics, respectively. A positive kinematic analysis of the posture adjusting mechanism was carried out, as well as a workspace analysis of the head and neck positioning device. Finally, positioning error experiment and ergonomic evaluation were performed on a prototype of the head and neck positioning device. The proposed design of the treatment chair satisfies the requirements for posture adjustment and achieves the head and neck positioning function. The experimental results also provide a basis for further optimization of the design.