为解决传统纸张表面缺陷检测人工依赖强、原始YOLOv5(You Only Look Once version 5)模型轻量化不足、多尺度缺陷检测精度低等问题,提出融合分组可分离卷积(Group Shuffle Convolution, GSconv)与双向加权特征金字塔网络(Bi-directional...为解决传统纸张表面缺陷检测人工依赖强、原始YOLOv5(You Only Look Once version 5)模型轻量化不足、多尺度缺陷检测精度低等问题,提出融合分组可分离卷积(Group Shuffle Convolution, GSconv)与双向加权特征金字塔网络(Bi-directional Feature Pyramid Network, BIFPN)的改进YOLOv5检测模型,构建纸张表面缺陷在线检测系统。模型通过GSconv替代骨干网络中的传统卷积实现轻量化,引入BIFPN强化多尺度特征融合,同时结合锚框优化与卷积块注意力模块提升小目标检测能力。实验结果显示,与原YOLOv5相比,改进模型骨干网络的参数减少28.3%,计算量降低31.5%;小目标缺陷检测精度提升12.3%,m AP达94.7%,较原始YOLOv5提升7.6%;推理速度达65 FPS,较原始模型提升32.1%。该系统满足了工业在线检测的实时性与精度需求,为纸张质量控制提供了新的技术支撑。展开更多
For high strength interstitial free （IF） steel containing P element, the salt and pepper （SP） defects exist on the strip surface and could not be eliminated effectively by optimizing the hot rolling process, such ...For high strength interstitial free （IF） steel containing P element, the salt and pepper （SP） defects exist on the strip surface and could not be eliminated effectively by optimizing the hot rolling process, such as temperature and cooling water. The combination effect of Si and P on the characteristic of tertiary scale has been studied comprehensively by scanning electron microscopy （SEM） and electron probe microanalysis （EPMA）, and the concept is proposed firstly that Si and P are of combination effect which can be utilized to eliminate the SP defect. The results show that the SP defects were induced by the rolled-in scale during finish rolling. P can be enriched at the interface between substrate and tertiary scale, which is easy to decrease the adhesion of tertiary scale. However, Si enrichment at the interface between substrate and tertiary scale can increase the adhesion. The SP defects can be eliminated completely, which is attributed to the accompanying enrichment of Si and P.展开更多
The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by...The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by forming defects in the transitional region.In this work,the feasibility of controlling forming defects and improving the process forming limit by adjusting die parameters is explored through finite element（FE） simulation.It is found that the common cavum and folding defects in the transitional region are significantly influenced by the fillet radii of left rib and middle rib,respectively.The cavum and folding defects can be effectively controlled by increasing the fillet radii of left rib and middle rib,respectively.The process forming limits considering forming defects in the transitional region are determined by the stepwise searching method under various die parameters.Moreover,the relationship between the process forming limit and die parameters is developed through the response surface methodology（RSM）.The developed RSM models suggest that increasing the fillet radii of left and middle ribs is effective to improve the process forming limit during local loading forming of rib-web components.The results will provide technical basis for the design of die parameters and the reduction amount,which is of great importance to control forming defects and improve the process forming limit in local loading forming of Ti-alloy large-scale rib-web components.展开更多
A multiple-time-scale algorithm is developed to numerically simulate certain structural components in civil structures where local defects inevitably exist. Spatially, the size of local defects is relatively small com...A multiple-time-scale algorithm is developed to numerically simulate certain structural components in civil structures where local defects inevitably exist. Spatially, the size of local defects is relatively small compared to the structural scale. Different length scales should be adopted considering the efficiency and computational cost. In the principle of physics, different length scales are stipulated to correspond to different time scales. This concept lays the foundation of the framework for this multiple-time-scale algorithm. A multiple-time-scale algorithm, which involves different time steps for different regions, while enforcing the compatibility of displacement, force and stress fields across the interface, is proposed. Furthermore, a defected beam component is studied as a numerical sample. The structural component is divided into two regions： a coarse one and a fine one; a micro-defect exists in the fine region and the finite element sizes of the two regions are diametrically different. Correspondingly, two different time steps are adopted. With dynamic load applied to the beam, stress and displacement distribution of the defected beam is investigated from the global and local perspectives. The numerical sample reflects that the proposed algorithm is physically rational and computationally efficient in the potential damage simulation of civil structures.展开更多
AIM: To show the efficacy of reconstruction and rehabilitation of large acquired maxillofacial defects due to tumor resections and firearm injuries. METHODS: The study group comprised of 16 patients(10 men and 6 women...AIM: To show the efficacy of reconstruction and rehabilitation of large acquired maxillofacial defects due to tumor resections and firearm injuries. METHODS: The study group comprised of 16 patients(10 men and 6 women) who were operated on because of their maxillofacial defects under local and general anesthesia between June 2007 and June 2011. Prosthetic treatment with the aid of dental implants was performed for all of the patients. Eight patients received an implant supported fixed prosthesis; six patients received implant supported overdentures and two patients received both. Patients were followed up postoperatively for 1 to 4 years. Implant success and survival rates were recorded. Panoramic radiographs were taken preoperatively, immediately after surgery, immediately after loading and at every recall session. Peri-implant and prosthetic complications were recorded. Subjects were asked to grade their oral health satisfaction after treatment according to 100 mm visual analog scale(VAS) and the oral health related quality oflife of the patients was measured with the short-form Oral Health Impact Profile. RESULTS: Five implants(3 in the mandible, 2 in the maxilla) in five patients were lost, while the other 53 survived, which brings an overall survival rate of 91.37% on the implant basis, but 68.75% on patient basis. All the failed implants were lost before abutment connection and were therefore regarded as early failures. For all failed implants, new implants were placed after a 2 mo period and the planning was maintained. The mean marginal bone loss(MBL) was 1.4 mm on the mesial side and 1.6 mm on the distal side of the implants. Five of the implants showed MBL > 2 mm(mean MBL = 2.3 mm) but less than 1/2 of the implant bodies and therefore were regarded as not successful but surviving implants. The VAS General Comfort mean score was 85.07, the VAS Speech mean score was 75.25 and the VAS Esthetics mean score was 82.74. No patient reported low scores(score lower than 50) of satisfaction in any of the evaluated factors. The mean of OHIP-14 scores was 5.5. CONCLUSION: Although further follow up and larger case numbers will give more information about the success of dental implants as a treatment modality in maxillofacial defects patients, the actual results are encouraging and can be recommended for similar cases.展开更多
文摘为解决传统纸张表面缺陷检测人工依赖强、原始YOLOv5(You Only Look Once version 5)模型轻量化不足、多尺度缺陷检测精度低等问题,提出融合分组可分离卷积(Group Shuffle Convolution, GSconv)与双向加权特征金字塔网络(Bi-directional Feature Pyramid Network, BIFPN)的改进YOLOv5检测模型,构建纸张表面缺陷在线检测系统。模型通过GSconv替代骨干网络中的传统卷积实现轻量化,引入BIFPN强化多尺度特征融合,同时结合锚框优化与卷积块注意力模块提升小目标检测能力。实验结果显示,与原YOLOv5相比,改进模型骨干网络的参数减少28.3%,计算量降低31.5%;小目标缺陷检测精度提升12.3%,m AP达94.7%,较原始YOLOv5提升7.6%;推理速度达65 FPS,较原始模型提升32.1%。该系统满足了工业在线检测的实时性与精度需求,为纸张质量控制提供了新的技术支撑。
文摘For high strength interstitial free （IF） steel containing P element, the salt and pepper （SP） defects exist on the strip surface and could not be eliminated effectively by optimizing the hot rolling process, such as temperature and cooling water. The combination effect of Si and P on the characteristic of tertiary scale has been studied comprehensively by scanning electron microscopy （SEM） and electron probe microanalysis （EPMA）, and the concept is proposed firstly that Si and P are of combination effect which can be utilized to eliminate the SP defect. The results show that the SP defects were induced by the rolled-in scale during finish rolling. P can be enriched at the interface between substrate and tertiary scale, which is easy to decrease the adhesion of tertiary scale. However, Si enrichment at the interface between substrate and tertiary scale can increase the adhesion. The SP defects can be eliminated completely, which is attributed to the accompanying enrichment of Si and P.
基金the support of the National Natural Science Foundation of China(Nos.51605388,51675433)111 Project(B08040)+2 种基金the Research Fund of the State Key Laboratory of Solidification Processing(NWPU)in China(Grant No.131-QP-2015)the Fundamental Research Funds for the Central Universitiesthe Open Research Fund of State Key Laboratory of Materials Processing and Die&Mold Technology at Huazhong University of Science and Technology
文摘The isothermal local loading forming technology provides a feasible way to form Ti-alloy large-scale rib-web components in aerospace and aviation fields.However,the local loading process forming limit is restricted by forming defects in the transitional region.In this work,the feasibility of controlling forming defects and improving the process forming limit by adjusting die parameters is explored through finite element（FE） simulation.It is found that the common cavum and folding defects in the transitional region are significantly influenced by the fillet radii of left rib and middle rib,respectively.The cavum and folding defects can be effectively controlled by increasing the fillet radii of left rib and middle rib,respectively.The process forming limits considering forming defects in the transitional region are determined by the stepwise searching method under various die parameters.Moreover,the relationship between the process forming limit and die parameters is developed through the response surface methodology（RSM）.The developed RSM models suggest that increasing the fillet radii of left and middle ribs is effective to improve the process forming limit during local loading forming of rib-web components.The results will provide technical basis for the design of die parameters and the reduction amount,which is of great importance to control forming defects and improve the process forming limit in local loading forming of Ti-alloy large-scale rib-web components.
基金supports from NSFC(No.11302078)China Postdoctoral Science Foundation(No.2013M531139)Shanghai Postdoctoral Sustentation Fund(No.12R21412000)
文摘A multiple-time-scale algorithm is developed to numerically simulate certain structural components in civil structures where local defects inevitably exist. Spatially, the size of local defects is relatively small compared to the structural scale. Different length scales should be adopted considering the efficiency and computational cost. In the principle of physics, different length scales are stipulated to correspond to different time scales. This concept lays the foundation of the framework for this multiple-time-scale algorithm. A multiple-time-scale algorithm, which involves different time steps for different regions, while enforcing the compatibility of displacement, force and stress fields across the interface, is proposed. Furthermore, a defected beam component is studied as a numerical sample. The structural component is divided into two regions： a coarse one and a fine one; a micro-defect exists in the fine region and the finite element sizes of the two regions are diametrically different. Correspondingly, two different time steps are adopted. With dynamic load applied to the beam, stress and displacement distribution of the defected beam is investigated from the global and local perspectives. The numerical sample reflects that the proposed algorithm is physically rational and computationally efficient in the potential damage simulation of civil structures.
文摘AIM: To show the efficacy of reconstruction and rehabilitation of large acquired maxillofacial defects due to tumor resections and firearm injuries. METHODS: The study group comprised of 16 patients(10 men and 6 women) who were operated on because of their maxillofacial defects under local and general anesthesia between June 2007 and June 2011. Prosthetic treatment with the aid of dental implants was performed for all of the patients. Eight patients received an implant supported fixed prosthesis; six patients received implant supported overdentures and two patients received both. Patients were followed up postoperatively for 1 to 4 years. Implant success and survival rates were recorded. Panoramic radiographs were taken preoperatively, immediately after surgery, immediately after loading and at every recall session. Peri-implant and prosthetic complications were recorded. Subjects were asked to grade their oral health satisfaction after treatment according to 100 mm visual analog scale(VAS) and the oral health related quality oflife of the patients was measured with the short-form Oral Health Impact Profile. RESULTS: Five implants(3 in the mandible, 2 in the maxilla) in five patients were lost, while the other 53 survived, which brings an overall survival rate of 91.37% on the implant basis, but 68.75% on patient basis. All the failed implants were lost before abutment connection and were therefore regarded as early failures. For all failed implants, new implants were placed after a 2 mo period and the planning was maintained. The mean marginal bone loss(MBL) was 1.4 mm on the mesial side and 1.6 mm on the distal side of the implants. Five of the implants showed MBL > 2 mm(mean MBL = 2.3 mm) but less than 1/2 of the implant bodies and therefore were regarded as not successful but surviving implants. The VAS General Comfort mean score was 85.07, the VAS Speech mean score was 75.25 and the VAS Esthetics mean score was 82.74. No patient reported low scores(score lower than 50) of satisfaction in any of the evaluated factors. The mean of OHIP-14 scores was 5.5. CONCLUSION: Although further follow up and larger case numbers will give more information about the success of dental implants as a treatment modality in maxillofacial defects patients, the actual results are encouraging and can be recommended for similar cases.
