In this paper,a linear optimization method(LOM)for the design of terahertz circuits is presented,aimed at enhancing the simulation efficacy and reducing the time of the circuit design workflow.This method enables the ...In this paper,a linear optimization method(LOM)for the design of terahertz circuits is presented,aimed at enhancing the simulation efficacy and reducing the time of the circuit design workflow.This method enables the rapid determination of optimal embedding impedance for diodes across a specific bandwidth to achieve maximum efficiency through harmonic balance simulations.By optimizing the linear matching circuit with the optimal embedding impedance,the method effectively segregates the simulation of the linear segments from the nonlinear segments in the frequency multiplier circuit,substantially improving the speed of simulations.The design of on-chip linear matching circuits adopts a modular circuit design strategy,incorporating fixed load resistors to simplify the matching challenge.Utilizing this approach,a 340 GHz frequency doubler was developed and measured.The results demonstrate that,across a bandwidth of 330 GHz to 342 GHz,the efficiency of the doubler remains above 10%,with an input power ranging from 98 mW to 141mW and an output power exceeding 13 mW.Notably,at an input power of 141 mW,a peak output power of 21.8 mW was achieved at 334 GHz,corresponding to an efficiency of 15.8%.展开更多
The three-dimensional(3D)geometry of a fault is a critical control on earthquake nucleation,dynamic rupture,stress triggering,and related seismic hazards.Therefore,a 3D model of an active fault can significantly impro...The three-dimensional(3D)geometry of a fault is a critical control on earthquake nucleation,dynamic rupture,stress triggering,and related seismic hazards.Therefore,a 3D model of an active fault can significantly improve our understanding of seismogenesis and our ability to evaluate seismic hazards.Utilising the SKUA GoCAD software,we constructed detailed seismic fault models for the 2021 M_(S)6.4 Yangbi earthquake in Yunnan,China,using two sets of relocated earthquake catalogs and focal mechanism solutions following a convenient 3D fault modeling workflow.Our analysis revealed a NW-striking main fault with a high-angle SW dip,accompanied by two branch faults.Interpretation of one dataset revealed a single NNW-striking branch fault SW of the main fault,whereas the other dataset indicated four steep NNE-striking segments with a left-echelon pattern.Additionally,a third ENE-striking short fault was identified NE of the main fault.In combination with the spatial distribution of pre-existing faults,our 3D fault models indicate that the Yangbi earthquake reactivated pre-existing NW-and NE-striking fault directions rather than the surface-exposed Weixi-Qiaohou-Weishan Fault zone.The occurrence of the Yangbi earthquake demonstrates that the reactivation of pre-existing faults away from active fault zones,through either cascade or conjugate rupture modes,can cause unexpected moderate-large earthquakes and severe disasters,necessitating attention in regions like southeast Xizang,which have complex fault systems.展开更多
Highway planning requires geological surveys and stability analysis of the surrounding area.In the early stage of the survey,the modeling and stability analysis of the survey area can be carried out by using GIS softw...Highway planning requires geological surveys and stability analysis of the surrounding area.In the early stage of the survey,the modeling and stability analysis of the survey area can be carried out by using GIS software to intuitively understand the topography of the study area.The use of DEM to extract terrain factors can be used for simple stability analysis and the source data is easy to obtain,simple to operate,fast to analyze,and reliable analysis results.In this paper,taking the X104 road section in Ganxian County as an example,the ArcGIS platform is used to carry out 3D modeling visualization and stability analysis,and the stability evaluation map of the study area is obtained.展开更多
With the development and popularization of computer application technology,the use of computer graphics and image processing technology has become the main means of modern engineering design and drawing.Learning and m...With the development and popularization of computer application technology,the use of computer graphics and image processing technology has become the main means of modern engineering design and drawing.Learning and mastering 3D modeling technology and mechanical information modeling technology have become an important goal of learning engineering drawing.To meet the teaching requirements of the“New Engineering”program,higher education should cultivate innovative talents with the ability to identify,express,analyze,and solve complex engineering problems;promote the transformation of teaching methods for the course of“Mechanical Drawing and Computer Drawing”from“teaching well”to“learning well.”This change is not only a change in course content,but also a change in training objectives.It introduces modern 3D design concepts into the drawing course,constructs a learning system with 3D modeling technology as the main line,solves the problem of imagination in traditional teaching,makes the learning process more in line with scientific cognitive laws,better meets the needs of modern manufacturing industry for new technologies,and improves students’drawing skills and ability to use modern tools(computer drawing).展开更多
Bacckground:Based on the 3C model,this study explores the current situation of HPV vaccine hesitancy among women of childbearing age and the factors influencing vaccine hesitancy.Methods:Based on the free cervical can...Bacckground:Based on the 3C model,this study explores the current situation of HPV vaccine hesitancy among women of childbearing age and the factors influencing vaccine hesitancy.Methods:Based on the free cervical cancer screening project in Baoan District,this study designed a questionnaire under the framework of vaccine hesitation 3C theory and carried out a self-filling electronic questionnaire survey among women of childbearing age.Results:The rate of HPV vaccination awareness among women of childbearing age in Bao’an District was 93.25%.HPV vaccine acceptance reached 71.55%,and 24.59%of the survey respondents experienced HPV vaccine hesitation,a high percentage of whom were hesitant.The influencing factors of HPV vaccine hesitation among women of childbearing age were perceived necessity of HPV vaccination(0.482),no one around them receiving the HPV vaccine(0.411),perception of the price of the vaccine(0.354),degree of trust in the safety of the vaccine(0.223),and degree of concern about the HPV vaccine(0.153).Conclusion:The 3C model can be used for the study of HPV vaccine hesitancy.Strengthening the publicity of HPV vaccination and improving women’s knowledge of the HPV vaccine can reduce their hesitation toward HPV vaccination.展开更多
Accurate retrieval of casting 3D models is crucial for process reuse.Current methods primarily focus on shape similarity,neglecting process design features,which compromises reusability.In this study,a novel deep lear...Accurate retrieval of casting 3D models is crucial for process reuse.Current methods primarily focus on shape similarity,neglecting process design features,which compromises reusability.In this study,a novel deep learning retrieval method for process reuse was proposed,which integrates process design features into the retrieval of casting 3D models.This method leverages the comparative language-image pretraining(CLIP)model to extract shape features from the three views and sectional views of the casting model and combines them with process design features such as modulus,main wall thickness,symmetry,and length-to-height ratio to enhance process reusability.A database of 230 production casting models was established for model validation.Results indicate that incorporating process design features improves model accuracy by 6.09%,reaching 97.82%,and increases process similarity by 30.25%.The reusability of the process was further verified using the casting simulation software EasyCast.The results show that the process retrieved after integrating process design features produces the least shrinkage in the target model,demonstrating this method’s superior ability for process reuse.This approach does not require a large dataset for training and optimization,making it highly applicable to casting process design and related manufacturing processes.展开更多
Throughout the 20th century, several large megathrust earthquakes were observed in the Colombia–Ecuador subduction zone which widely ruptured plate interfaces, causing considerable damage and loss of life. The occurr...Throughout the 20th century, several large megathrust earthquakes were observed in the Colombia–Ecuador subduction zone which widely ruptured plate interfaces, causing considerable damage and loss of life. The occurrence of earthquakes in subduction zones is thought to be closely related to the thermal structure of the incoming plate. However, in the case of the subducting Nazca Plate beneath the Colombia–Ecuador zone, the thermal structure remains unclear, especially its hydraulic distribution. On the basis of 3D thermal models, we present new insights into the plate interface conditions of Colombia–Ecuador interplate and megathrust earthquakes. We show that the plate geometry strongly affects the along-strike thermal structure of the slab beneath Colombia and Ecuador, with the subduction of the Carnegie Ridge playing an important role. Our results further reveal that the unique geometry of the Nazca Plate is the primary reason for the relatively high temperatures of the slab beneath Colombia. We suggest that the positions of the100–200 ℃ and 350–450 ℃ isotherms on the plate interface determine the updip and downdip limits of the seismogenic zone. For Colombia–Ecuador interplate earthquakes, the released fluids control the distribution of shallow-depth earthquakes, whereas the age and geometry of the slab control the distribution of intermediate-depth earthquakes. The average temperature of the plate interface at the upper limit of large megathrust earthquakes is hotter than previously thought, which is more consistent with our understanding of the Colombia–Ecuador subduction zone. We predict that the potential location of future large seismic events could be in the rupture zone of past seismic events or offshore of northern Colombia.展开更多
Tree rings provide long-term records of tree growth and climate changes,which makes them ideal benchmarks for forest modeling.Tree-ring information has greatly improved the reliability of 3-PG,which is one of the most...Tree rings provide long-term records of tree growth and climate changes,which makes them ideal benchmarks for forest modeling.Tree-ring information has greatly improved the reliability of 3-PG,which is one of the most commonly used process-based forest growth models.Here,we strengthen 3-PG's ability to simulate tree-ring width and stable carbon isotopes(δ^(13)C)by enhancing its descriptions of tree physiology.The major upgrade was adding a carbon storage pool for tree-ring formation using stored carbohydrates.We also incorporated previous modifications(replacing the age modifier with a height modifier)of 3-PG and tested their efficacy in improving tree-ring simulations.We ran the model based on two grand fir(Abies grandis)stands.The updated model greatly improved the simulations for both tree-ring widths andδ^(13)C.The results represent one of the best tree-ringδ^(13)C simulations,which accurately captured the amplitude in annual variations ofδ^(13)C.The correlations(R^(2))between simulations and observations reached 0.50 and 0.73 at two stands,respectively.The new model also greatly improved the simulations of raw tree-ring widths and detrended ring-width index(RWI).Because of better descriptions of tree physiology and more accurate simulations of tree rings than the previous model version,the updated 3-PG should provide more reliable simulations than previous 3-PG versions when tree-ring information is used as a benchmark in future studies.展开更多
3D model classification has emerged as a significant research focus in computer vision.However,traditional convolutional neural networks(CNNs)often struggle to capture global dependencies across both height and width ...3D model classification has emerged as a significant research focus in computer vision.However,traditional convolutional neural networks(CNNs)often struggle to capture global dependencies across both height and width dimensions simultaneously,leading to limited feature representation capabilities when handling complex visual tasks.To address this challenge,we propose a novel 3D model classification network named ViT-GE(Vision Transformer with Global and Efficient Attention),which integrates Global Grouped Coordinate Attention(GGCA)and Efficient Channel Attention(ECA)mechanisms.Specifically,the Vision Transformer(ViT)is employed to extract comprehensive global features from multi-view inputs using its self-attention mechanism,effectively capturing 3D shape characteristics.To further enhance spatial feature modeling,the GGCA module introduces a grouping strategy and global context interactions.Concurrently,the ECA module strengthens inter-channel information flow,enabling the network to adaptively emphasize key features and improve feature fusion.Finally,a voting mechanism is adopted to enhance classification accuracy,robustness,and stability.Experimental results on the ModelNet10 dataset demonstrate that our method achieves a classification accuracy of 93.50%,validating its effectiveness and superior performance.展开更多
The dependence of the subduction regime on three-dimensional slab geometry poses a challenge for accurately estimating the evolving thermal structure of megathrusts globally. Although slab dips and ages have gained at...The dependence of the subduction regime on three-dimensional slab geometry poses a challenge for accurately estimating the evolving thermal structure of megathrusts globally. Although slab dips and ages have gained attention, the specific impacts of oblique subduction remain unmeasured. Here, we present an integrated thermal model that quantifies how slab morphology can shape the thermal state of megathrusts, such as those in the Makran Subduction Zone. The model considers both slab obliquity and depth variations along the trench. We find a considerable match between the slab petrological dehydration zone and the distribution of great crustal earthquakes. We suggest that the accumulation of fluids along megathrusts by slab metamorphism can foster more polarized conditions for decreasing plate coupling and increasing interplate ruptures. It is thus imperative to improve model representation and more realistically represent how drivers of slab geometry affect metamorphic transitions and the occurrence of earthquakes at megathrusts.展开更多
The utilization of unused rooftops is a promising solution to meet the growing energy needs of urban areas.This study identifies the strategic locations for installing photovoltaic(PV)systems and assesses the energy p...The utilization of unused rooftops is a promising solution to meet the growing energy needs of urban areas.This study identifies the strategic locations for installing photovoltaic(PV)systems and assesses the energy production in Nador,Morocco,comparing various PV modules based on sunlight,while also integrating an economic analysis.A key innovation of this study lies in the novel application of LiDAR(Light Detection and Ranging)point clouds combined with photogrammetric restitution,enabling the construction of a 3D model of buildings.A Boolean multicriteria analysis was implemented to determine the effective surface area of each roof,considering param-eters,such as slope,orientation,shadow,and accessibility,while excluding unsuitable buildings.A substantial area of 336 ha suitable for solar systems was identified,representing 61%of the total area of existing structures,with an average annual irradiation of 1,413.71 kWh/m^(2).The CIS(copper/indium/selenium)PV module stands out as an attractive option,offering an energy capacity of 168.56 MWp and significant energy production of 311.35 GWh.Their moderate initial cost of 376.95 million USD makes themfinancially appealing with a feasible return on investment within 10 years.Environmentally,the CIS module contributes notably to reduced CO_(2) emissions,thereby mitigating its environmental impact.By implementing the CIS module,solar energy production is expected to significantly exceed the estimated demand of the urban population.The data were integrated into a Geographic Information System to target roofs suitable for solar panels,forming the basis of an accurate solar cadastre.This study actively contributes to shaping a sustainable energy landscape by promoting environment-friendly solutions,thereby playing a role in transitioning to a more sustainable energy future in Nador.展开更多
Jerada coal mining generates extensive coal mine waste rock(CMWR)piles rich in valuable minerals,posing environmental challenges and economic opportunities.This study examines reprocessing feasibility through 3D geome...Jerada coal mining generates extensive coal mine waste rock(CMWR)piles rich in valuable minerals,posing environmental challenges and economic opportunities.This study examines reprocessing feasibility through 3D geometallurgical characterization.Sampling used down the hole hammer drilling technique(DTH)and drone surveys for topographical precision.Over 620 samples from(T01,T02,T08)underwent comprehensive analyses including particle size distribution,x-ray fluorescence(XRF),total sulfur/carbon analysis(S/C),and inductively coupled plasma mass spectrometry(ICP-MS)for physical-chemical characterization.Mineralogical aspects were explored via optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),electron probe microanalysis(EPMA),and laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS).Quantitative mineral evaluation by scanning electron microscope(QEMSCAN)provided mineral insights.Chemical data was used in a 3D block model to quantify residual coal.Results for the three examined CMWR piles(T01,T02,and T08)showed varying D80 from 160 to 300μm,notable carbon content averaged 12.5 wt%(T01),16 wt%(T02),and 8.5 wt%(T08).Sulfur presence exceeded 1 wt%in T08,and potential environmental concerns due to iron sulfides.Anthracite liberation was below 30 wt%.3D modeling estimated a total volume of 7 Mm3,mainly from T08,equaling 11.2 Mt.With its high carbon content and substantial tonnages,re-exploitation or alternative applications could minimize these CMWR piles environmental impact.展开更多
Accurate vector extraction from design drawings is required first to automatically create 3D models from pixel-level engineering design drawings. However, this task faces the challenges of complicated design shapes as...Accurate vector extraction from design drawings is required first to automatically create 3D models from pixel-level engineering design drawings. However, this task faces the challenges of complicated design shapes as well as cumbersome and cluttered annotations on drawings, which interfere with the vector extraction heavily. In this article, the transmission tower containing the most complex structure is taken as the research object, and a semantic segmentation network is constructed to first segment the shape masks from the pixel-level drawings. Preprocessing and postprocessing are also proposed to ensure the stability and accuracy of the shape mask segmentation. Then, based on the obtained shape masks, a vector extraction network guided by heatmaps is designed to extract structural vectors by fusing the features from node heatmap and skeleton heatmap, respectively. Compared with the state-of-the-art methods, experiment results illustrate that the proposed semantic segmentation method can effectively eliminate the interference of many elements on drawings to segment the shape masks effectively, meanwhile, the model trained by the proposed vector extraction network can accurately extract the vectors such as nodes and line connections, avoiding redundant vector detection. The proposed method lays a solid foundation for automatic 3D model reconstruction and contributes to technological advancements in relevant fields.展开更多
With the widespread application of 3D visualization in digital exhibition halls and virtual reality,achieving efficient rendering and high-fidelity presentation has become a key challenge.This study proposes a hybrid ...With the widespread application of 3D visualization in digital exhibition halls and virtual reality,achieving efficient rendering and high-fidelity presentation has become a key challenge.This study proposes a hybrid point cloud generation method that combines traditional sampling with 3D Gaussian splatting,aiming to address the issues of rendering delay and missing details in existing 3D displays.By improving the OBJ model parsing process and incorporating an adaptive area-weighted sampling algorithm,we achieve adaptive point cloud generation based on triangle density.Innovatively,we advance the ellipsoidal parameter estimation process of 3D Gaussian splatting to the point cloud generation stage.By establishing a mathematical relationship between the covariance matrix and local curvature,the generated point cloud naturally exhibits Gaussian distribution characteristics.Experimental results show that,compared to traditional methods,our approach reduces point cloud data by 38% while maintaining equivalent visual quality at a 4096×4096 texture resolution.By introducing mipmap texture optimization strategies and a GPU-accelerated rasterization pipeline,stable rendering at 60 frames per second is achieved in a WebGL environment.Additionally,we quantize and compress the spherical harmonic function parameters specific to 3D Gaussian splatting,reducing network transmission bandwidth to 52% of the original data.This study provides a new technical pathway for fields requiring high-precision display,such as the digitization of cultural heritage.展开更多
Objective:Critically appraise the current state of alternate temporal bone training techniques(virtual reality(VR)simulation,3D-printed models,and mental practice(MP))compared to traditional and cadaver methods.Databa...Objective:Critically appraise the current state of alternate temporal bone training techniques(virtual reality(VR)simulation,3D-printed models,and mental practice(MP))compared to traditional and cadaver methods.Databases Reviewed:PubMed,Cochrane,Web of Science.Methods:Search terms utilized“temporal bone training”,“temporal bone surgical modalities”,and“training modalities temporal bone surgery”with“3D”,“rapid prototyp*”,“stereolithography”,“additive manufact*”,“plaster”,“VR”,“virtual reality”,“animal model”,“animal temporal bone”,and“synthetic”with“AND”for all literature.Exclusion criteria:non-ENT,non-English,and did not compare against alternative/traditional methods.Results:10 studies were included with 322 participants(83.9%ENT residents and 16.1%medical students).Costs include the FDM printer($300),materials($5/3D model),and<$5,000 for freeware simulator hardware.The Welling scale was used in 50%of studies.Alternate methods produced comparable or improved assessment scores to traditional and cadaver methods.Injuries were reported in three VR studies,with two reported significantly lower injury scores in the intervention groups.Time to completion was not significantly different in four VR studies,except for one finding that the time to visualize the incus was significantly lower in the intervention group.Performance after MP was not statistically different.Conclusion:More data are needed to assess whether the alternate methods are comparable to cadaveric dissection in temporal bone training.3D models and VR simulation demonstrate promising potential for novel trainees to acquire the basic skills and produce performance comparable to or significantly better than traditional methods of lectures,textbooks,CT images,and operative videos.展开更多
This paper presents a novel method for reconstructing a highly accurate 3D nose model of the human from 2D images and pre-marked landmarks based on algorithmic methods.The study focuses on the reconstruction of a 3D n...This paper presents a novel method for reconstructing a highly accurate 3D nose model of the human from 2D images and pre-marked landmarks based on algorithmic methods.The study focuses on the reconstruction of a 3D nose model tailored for applications in healthcare and cosmetic surgery.The approach leverages advanced image processing techniques,3D Morphable Models(3DMM),and deformation techniques to overcome the limita-tions of deep learning models,particularly addressing the interpretability issues commonly encountered in medical applications.The proposed method estimates the 3D coordinates of landmark points using a 3D structure estimation algorithm.Sub-landmarks are extracted through image processing techniques and interpolation.The initial surface is generated using a 3DMM,though its accuracy remains limited.To enhance precision,deformation techniques are applied,utilizing the coordinates of 76 identified landmarks and sub-landmarks.The resulting 3D nose model is constructed based on algorithmic methods and pre-marked landmarks.Evaluation of the 3D model is conducted by comparing landmark distances and shape similarity with expert-determined ground truth on 30 Vietnamese volunteers aged 18 to 47,all of whom were either preparing for or required nasal surgery.Experimental results demonstrate a strong agreement between the reconstructed 3D model and the ground truth.The method achieved a mean landmark distance error of 0.631 mm and a shape error of 1.738 mm,demonstrating its potential for medical applications.展开更多
基金Supported by the Beijing Municipal Science&Technology Commission(Z211100004421012),the Key Reaserch and Development Pro⁃gram of China(2022YFF0605902)。
文摘In this paper,a linear optimization method(LOM)for the design of terahertz circuits is presented,aimed at enhancing the simulation efficacy and reducing the time of the circuit design workflow.This method enables the rapid determination of optimal embedding impedance for diodes across a specific bandwidth to achieve maximum efficiency through harmonic balance simulations.By optimizing the linear matching circuit with the optimal embedding impedance,the method effectively segregates the simulation of the linear segments from the nonlinear segments in the frequency multiplier circuit,substantially improving the speed of simulations.The design of on-chip linear matching circuits adopts a modular circuit design strategy,incorporating fixed load resistors to simplify the matching challenge.Utilizing this approach,a 340 GHz frequency doubler was developed and measured.The results demonstrate that,across a bandwidth of 330 GHz to 342 GHz,the efficiency of the doubler remains above 10%,with an input power ranging from 98 mW to 141mW and an output power exceeding 13 mW.Notably,at an input power of 141 mW,a peak output power of 21.8 mW was achieved at 334 GHz,corresponding to an efficiency of 15.8%.
基金financial support from the National Key R&D Program of China (No. 2021YFC3000600)National Natural Science Foundation of China (No. 41872206)National Nonprofit Fundamental Research Grant of China, Institute of Geology, China, Earthquake Administration (No. IGCEA2010)
文摘The three-dimensional(3D)geometry of a fault is a critical control on earthquake nucleation,dynamic rupture,stress triggering,and related seismic hazards.Therefore,a 3D model of an active fault can significantly improve our understanding of seismogenesis and our ability to evaluate seismic hazards.Utilising the SKUA GoCAD software,we constructed detailed seismic fault models for the 2021 M_(S)6.4 Yangbi earthquake in Yunnan,China,using two sets of relocated earthquake catalogs and focal mechanism solutions following a convenient 3D fault modeling workflow.Our analysis revealed a NW-striking main fault with a high-angle SW dip,accompanied by two branch faults.Interpretation of one dataset revealed a single NNW-striking branch fault SW of the main fault,whereas the other dataset indicated four steep NNE-striking segments with a left-echelon pattern.Additionally,a third ENE-striking short fault was identified NE of the main fault.In combination with the spatial distribution of pre-existing faults,our 3D fault models indicate that the Yangbi earthquake reactivated pre-existing NW-and NE-striking fault directions rather than the surface-exposed Weixi-Qiaohou-Weishan Fault zone.The occurrence of the Yangbi earthquake demonstrates that the reactivation of pre-existing faults away from active fault zones,through either cascade or conjugate rupture modes,can cause unexpected moderate-large earthquakes and severe disasters,necessitating attention in regions like southeast Xizang,which have complex fault systems.
基金National Undergraduate Training Program for Innovation and Entrepreneurship(Project No.:202310407006)。
文摘Highway planning requires geological surveys and stability analysis of the surrounding area.In the early stage of the survey,the modeling and stability analysis of the survey area can be carried out by using GIS software to intuitively understand the topography of the study area.The use of DEM to extract terrain factors can be used for simple stability analysis and the source data is easy to obtain,simple to operate,fast to analyze,and reliable analysis results.In this paper,taking the X104 road section in Ganxian County as an example,the ArcGIS platform is used to carry out 3D modeling visualization and stability analysis,and the stability evaluation map of the study area is obtained.
文摘With the development and popularization of computer application technology,the use of computer graphics and image processing technology has become the main means of modern engineering design and drawing.Learning and mastering 3D modeling technology and mechanical information modeling technology have become an important goal of learning engineering drawing.To meet the teaching requirements of the“New Engineering”program,higher education should cultivate innovative talents with the ability to identify,express,analyze,and solve complex engineering problems;promote the transformation of teaching methods for the course of“Mechanical Drawing and Computer Drawing”from“teaching well”to“learning well.”This change is not only a change in course content,but also a change in training objectives.It introduces modern 3D design concepts into the drawing course,constructs a learning system with 3D modeling technology as the main line,solves the problem of imagination in traditional teaching,makes the learning process more in line with scientific cognitive laws,better meets the needs of modern manufacturing industry for new technologies,and improves students’drawing skills and ability to use modern tools(computer drawing).
基金District of Medical and Health Research Project(2023JD212)Shenzhen Bao’an District of Traditional Chinese Medicine Clinical Research Project(2023ZYYLCZX-12)+2 种基金Shenzhen“Medical and Health Three Projects”Project Grant(SZZYSM 202106003)Weifang Health Committee Scientific Research Project(wfwsjk-2023-170)Shenzhen Pingshan District of Health System Research Project(2024334).
文摘Bacckground:Based on the 3C model,this study explores the current situation of HPV vaccine hesitancy among women of childbearing age and the factors influencing vaccine hesitancy.Methods:Based on the free cervical cancer screening project in Baoan District,this study designed a questionnaire under the framework of vaccine hesitation 3C theory and carried out a self-filling electronic questionnaire survey among women of childbearing age.Results:The rate of HPV vaccination awareness among women of childbearing age in Bao’an District was 93.25%.HPV vaccine acceptance reached 71.55%,and 24.59%of the survey respondents experienced HPV vaccine hesitation,a high percentage of whom were hesitant.The influencing factors of HPV vaccine hesitation among women of childbearing age were perceived necessity of HPV vaccination(0.482),no one around them receiving the HPV vaccine(0.411),perception of the price of the vaccine(0.354),degree of trust in the safety of the vaccine(0.223),and degree of concern about the HPV vaccine(0.153).Conclusion:The 3C model can be used for the study of HPV vaccine hesitancy.Strengthening the publicity of HPV vaccination and improving women’s knowledge of the HPV vaccine can reduce their hesitation toward HPV vaccination.
基金supported by the National Natural Science Foundation of China(Nos.52074246,52275390,52375394)the National Defense Basic Scientific Research Program of China(No.JCKY2020408B002)the Key R&D Program of Shanxi Province(No.202102050201011).
文摘Accurate retrieval of casting 3D models is crucial for process reuse.Current methods primarily focus on shape similarity,neglecting process design features,which compromises reusability.In this study,a novel deep learning retrieval method for process reuse was proposed,which integrates process design features into the retrieval of casting 3D models.This method leverages the comparative language-image pretraining(CLIP)model to extract shape features from the three views and sectional views of the casting model and combines them with process design features such as modulus,main wall thickness,symmetry,and length-to-height ratio to enhance process reusability.A database of 230 production casting models was established for model validation.Results indicate that incorporating process design features improves model accuracy by 6.09%,reaching 97.82%,and increases process similarity by 30.25%.The reusability of the process was further verified using the casting simulation software EasyCast.The results show that the process retrieved after integrating process design features produces the least shrinkage in the target model,demonstrating this method’s superior ability for process reuse.This approach does not require a large dataset for training and optimization,making it highly applicable to casting process design and related manufacturing processes.
基金benefited from the financial support of the CAS Pioneer Hundred Talents Program and the Second Tibetan Plateau Scientific Expedition and Research Program (2019QZKK0708)。
文摘Throughout the 20th century, several large megathrust earthquakes were observed in the Colombia–Ecuador subduction zone which widely ruptured plate interfaces, causing considerable damage and loss of life. The occurrence of earthquakes in subduction zones is thought to be closely related to the thermal structure of the incoming plate. However, in the case of the subducting Nazca Plate beneath the Colombia–Ecuador zone, the thermal structure remains unclear, especially its hydraulic distribution. On the basis of 3D thermal models, we present new insights into the plate interface conditions of Colombia–Ecuador interplate and megathrust earthquakes. We show that the plate geometry strongly affects the along-strike thermal structure of the slab beneath Colombia and Ecuador, with the subduction of the Carnegie Ridge playing an important role. Our results further reveal that the unique geometry of the Nazca Plate is the primary reason for the relatively high temperatures of the slab beneath Colombia. We suggest that the positions of the100–200 ℃ and 350–450 ℃ isotherms on the plate interface determine the updip and downdip limits of the seismogenic zone. For Colombia–Ecuador interplate earthquakes, the released fluids control the distribution of shallow-depth earthquakes, whereas the age and geometry of the slab control the distribution of intermediate-depth earthquakes. The average temperature of the plate interface at the upper limit of large megathrust earthquakes is hotter than previously thought, which is more consistent with our understanding of the Colombia–Ecuador subduction zone. We predict that the potential location of future large seismic events could be in the rupture zone of past seismic events or offshore of northern Colombia.
基金supported by the National Natural Science Foundation of China(Nos.42271048,42430503,and 31971492).
文摘Tree rings provide long-term records of tree growth and climate changes,which makes them ideal benchmarks for forest modeling.Tree-ring information has greatly improved the reliability of 3-PG,which is one of the most commonly used process-based forest growth models.Here,we strengthen 3-PG's ability to simulate tree-ring width and stable carbon isotopes(δ^(13)C)by enhancing its descriptions of tree physiology.The major upgrade was adding a carbon storage pool for tree-ring formation using stored carbohydrates.We also incorporated previous modifications(replacing the age modifier with a height modifier)of 3-PG and tested their efficacy in improving tree-ring simulations.We ran the model based on two grand fir(Abies grandis)stands.The updated model greatly improved the simulations for both tree-ring widths andδ^(13)C.The results represent one of the best tree-ringδ^(13)C simulations,which accurately captured the amplitude in annual variations ofδ^(13)C.The correlations(R^(2))between simulations and observations reached 0.50 and 0.73 at two stands,respectively.The new model also greatly improved the simulations of raw tree-ring widths and detrended ring-width index(RWI).Because of better descriptions of tree physiology and more accurate simulations of tree rings than the previous model version,the updated 3-PG should provide more reliable simulations than previous 3-PG versions when tree-ring information is used as a benchmark in future studies.
基金funded by the project supported by the Heilongjiang Provincial Natural Science Foundation of China(Grant Number LH2022F030).
文摘3D model classification has emerged as a significant research focus in computer vision.However,traditional convolutional neural networks(CNNs)often struggle to capture global dependencies across both height and width dimensions simultaneously,leading to limited feature representation capabilities when handling complex visual tasks.To address this challenge,we propose a novel 3D model classification network named ViT-GE(Vision Transformer with Global and Efficient Attention),which integrates Global Grouped Coordinate Attention(GGCA)and Efficient Channel Attention(ECA)mechanisms.Specifically,the Vision Transformer(ViT)is employed to extract comprehensive global features from multi-view inputs using its self-attention mechanism,effectively capturing 3D shape characteristics.To further enhance spatial feature modeling,the GGCA module introduces a grouping strategy and global context interactions.Concurrently,the ECA module strengthens inter-channel information flow,enabling the network to adaptively emphasize key features and improve feature fusion.Finally,a voting mechanism is adopted to enhance classification accuracy,robustness,and stability.Experimental results on the ModelNet10 dataset demonstrate that our method achieves a classification accuracy of 93.50%,validating its effectiveness and superior performance.
基金benefited from the financial support of the Chinese Academy of Sciences Pioneer Hundred Talents Programthe Second Tibetan Plateau Scientific Expedition and Research Program (Grant No. 2019QZKK0708)+2 种基金the MEXT KAKENHI grant (Grant No. 21H05203)the Kobe University Strategic International Collaborative Research Grant (Type B Fostering Joint Research)the “Science of Slowto-Fast Earthquakes” project。
文摘The dependence of the subduction regime on three-dimensional slab geometry poses a challenge for accurately estimating the evolving thermal structure of megathrusts globally. Although slab dips and ages have gained attention, the specific impacts of oblique subduction remain unmeasured. Here, we present an integrated thermal model that quantifies how slab morphology can shape the thermal state of megathrusts, such as those in the Makran Subduction Zone. The model considers both slab obliquity and depth variations along the trench. We find a considerable match between the slab petrological dehydration zone and the distribution of great crustal earthquakes. We suggest that the accumulation of fluids along megathrusts by slab metamorphism can foster more polarized conditions for decreasing plate coupling and increasing interplate ruptures. It is thus imperative to improve model representation and more realistically represent how drivers of slab geometry affect metamorphic transitions and the occurrence of earthquakes at megathrusts.
文摘The utilization of unused rooftops is a promising solution to meet the growing energy needs of urban areas.This study identifies the strategic locations for installing photovoltaic(PV)systems and assesses the energy production in Nador,Morocco,comparing various PV modules based on sunlight,while also integrating an economic analysis.A key innovation of this study lies in the novel application of LiDAR(Light Detection and Ranging)point clouds combined with photogrammetric restitution,enabling the construction of a 3D model of buildings.A Boolean multicriteria analysis was implemented to determine the effective surface area of each roof,considering param-eters,such as slope,orientation,shadow,and accessibility,while excluding unsuitable buildings.A substantial area of 336 ha suitable for solar systems was identified,representing 61%of the total area of existing structures,with an average annual irradiation of 1,413.71 kWh/m^(2).The CIS(copper/indium/selenium)PV module stands out as an attractive option,offering an energy capacity of 168.56 MWp and significant energy production of 311.35 GWh.Their moderate initial cost of 376.95 million USD makes themfinancially appealing with a feasible return on investment within 10 years.Environmentally,the CIS module contributes notably to reduced CO_(2) emissions,thereby mitigating its environmental impact.By implementing the CIS module,solar energy production is expected to significantly exceed the estimated demand of the urban population.The data were integrated into a Geographic Information System to target roofs suitable for solar panels,forming the basis of an accurate solar cadastre.This study actively contributes to shaping a sustainable energy landscape by promoting environment-friendly solutions,thereby playing a role in transitioning to a more sustainable energy future in Nador.
基金financial support from the International Research Chairs Initiativea program funded by the International Development Research Centre,Canada(IDRC)facilitated by the Canadian Research Chairs Program(108469-001 and 109418-006).
文摘Jerada coal mining generates extensive coal mine waste rock(CMWR)piles rich in valuable minerals,posing environmental challenges and economic opportunities.This study examines reprocessing feasibility through 3D geometallurgical characterization.Sampling used down the hole hammer drilling technique(DTH)and drone surveys for topographical precision.Over 620 samples from(T01,T02,T08)underwent comprehensive analyses including particle size distribution,x-ray fluorescence(XRF),total sulfur/carbon analysis(S/C),and inductively coupled plasma mass spectrometry(ICP-MS)for physical-chemical characterization.Mineralogical aspects were explored via optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),electron probe microanalysis(EPMA),and laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS).Quantitative mineral evaluation by scanning electron microscope(QEMSCAN)provided mineral insights.Chemical data was used in a 3D block model to quantify residual coal.Results for the three examined CMWR piles(T01,T02,and T08)showed varying D80 from 160 to 300μm,notable carbon content averaged 12.5 wt%(T01),16 wt%(T02),and 8.5 wt%(T08).Sulfur presence exceeded 1 wt%in T08,and potential environmental concerns due to iron sulfides.Anthracite liberation was below 30 wt%.3D modeling estimated a total volume of 7 Mm3,mainly from T08,equaling 11.2 Mt.With its high carbon content and substantial tonnages,re-exploitation or alternative applications could minimize these CMWR piles environmental impact.
基金funded by the Chinese State Grid Jiangsu Electric Power Co.,Ltd.Science and Technology Project Funding,Grant Number J2023031.
文摘Accurate vector extraction from design drawings is required first to automatically create 3D models from pixel-level engineering design drawings. However, this task faces the challenges of complicated design shapes as well as cumbersome and cluttered annotations on drawings, which interfere with the vector extraction heavily. In this article, the transmission tower containing the most complex structure is taken as the research object, and a semantic segmentation network is constructed to first segment the shape masks from the pixel-level drawings. Preprocessing and postprocessing are also proposed to ensure the stability and accuracy of the shape mask segmentation. Then, based on the obtained shape masks, a vector extraction network guided by heatmaps is designed to extract structural vectors by fusing the features from node heatmap and skeleton heatmap, respectively. Compared with the state-of-the-art methods, experiment results illustrate that the proposed semantic segmentation method can effectively eliminate the interference of many elements on drawings to segment the shape masks effectively, meanwhile, the model trained by the proposed vector extraction network can accurately extract the vectors such as nodes and line connections, avoiding redundant vector detection. The proposed method lays a solid foundation for automatic 3D model reconstruction and contributes to technological advancements in relevant fields.
文摘With the widespread application of 3D visualization in digital exhibition halls and virtual reality,achieving efficient rendering and high-fidelity presentation has become a key challenge.This study proposes a hybrid point cloud generation method that combines traditional sampling with 3D Gaussian splatting,aiming to address the issues of rendering delay and missing details in existing 3D displays.By improving the OBJ model parsing process and incorporating an adaptive area-weighted sampling algorithm,we achieve adaptive point cloud generation based on triangle density.Innovatively,we advance the ellipsoidal parameter estimation process of 3D Gaussian splatting to the point cloud generation stage.By establishing a mathematical relationship between the covariance matrix and local curvature,the generated point cloud naturally exhibits Gaussian distribution characteristics.Experimental results show that,compared to traditional methods,our approach reduces point cloud data by 38% while maintaining equivalent visual quality at a 4096×4096 texture resolution.By introducing mipmap texture optimization strategies and a GPU-accelerated rasterization pipeline,stable rendering at 60 frames per second is achieved in a WebGL environment.Additionally,we quantize and compress the spherical harmonic function parameters specific to 3D Gaussian splatting,reducing network transmission bandwidth to 52% of the original data.This study provides a new technical pathway for fields requiring high-precision display,such as the digitization of cultural heritage.
文摘Objective:Critically appraise the current state of alternate temporal bone training techniques(virtual reality(VR)simulation,3D-printed models,and mental practice(MP))compared to traditional and cadaver methods.Databases Reviewed:PubMed,Cochrane,Web of Science.Methods:Search terms utilized“temporal bone training”,“temporal bone surgical modalities”,and“training modalities temporal bone surgery”with“3D”,“rapid prototyp*”,“stereolithography”,“additive manufact*”,“plaster”,“VR”,“virtual reality”,“animal model”,“animal temporal bone”,and“synthetic”with“AND”for all literature.Exclusion criteria:non-ENT,non-English,and did not compare against alternative/traditional methods.Results:10 studies were included with 322 participants(83.9%ENT residents and 16.1%medical students).Costs include the FDM printer($300),materials($5/3D model),and<$5,000 for freeware simulator hardware.The Welling scale was used in 50%of studies.Alternate methods produced comparable or improved assessment scores to traditional and cadaver methods.Injuries were reported in three VR studies,with two reported significantly lower injury scores in the intervention groups.Time to completion was not significantly different in four VR studies,except for one finding that the time to visualize the incus was significantly lower in the intervention group.Performance after MP was not statistically different.Conclusion:More data are needed to assess whether the alternate methods are comparable to cadaveric dissection in temporal bone training.3D models and VR simulation demonstrate promising potential for novel trainees to acquire the basic skills and produce performance comparable to or significantly better than traditional methods of lectures,textbooks,CT images,and operative videos.
文摘This paper presents a novel method for reconstructing a highly accurate 3D nose model of the human from 2D images and pre-marked landmarks based on algorithmic methods.The study focuses on the reconstruction of a 3D nose model tailored for applications in healthcare and cosmetic surgery.The approach leverages advanced image processing techniques,3D Morphable Models(3DMM),and deformation techniques to overcome the limita-tions of deep learning models,particularly addressing the interpretability issues commonly encountered in medical applications.The proposed method estimates the 3D coordinates of landmark points using a 3D structure estimation algorithm.Sub-landmarks are extracted through image processing techniques and interpolation.The initial surface is generated using a 3DMM,though its accuracy remains limited.To enhance precision,deformation techniques are applied,utilizing the coordinates of 76 identified landmarks and sub-landmarks.The resulting 3D nose model is constructed based on algorithmic methods and pre-marked landmarks.Evaluation of the 3D model is conducted by comparing landmark distances and shape similarity with expert-determined ground truth on 30 Vietnamese volunteers aged 18 to 47,all of whom were either preparing for or required nasal surgery.Experimental results demonstrate a strong agreement between the reconstructed 3D model and the ground truth.The method achieved a mean landmark distance error of 0.631 mm and a shape error of 1.738 mm,demonstrating its potential for medical applications.
