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Equivalence of Dynamicity and Balance of Category in “INCEPTION”
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作者 胡艳彬 《海外英语》 2011年第7X期292-293,共2页
"INCEPTION" has become a blockbuster recently and this word reflects the phenomenon:meaning expanding in a specific context,which,as a matter of fact,lives in many fields such as literature,films and speeche... "INCEPTION" has become a blockbuster recently and this word reflects the phenomenon:meaning expanding in a specific context,which,as a matter of fact,lives in many fields such as literature,films and speeches.Such words or phrases have both surface and deep meanings whose translation research is mainly placed on literal or literary transfer,leaving out their dynamicity and balance in meaning category.This paper aims to give a brief analysis on such phenomenon and puts forward to a new translation principle:category equivalence in dynamicity and balance. 展开更多
关键词 MEANING EQUIVALENCE CATEGORY dynamicity BALANCE
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Tensile failure mode transitions from subzero to elevated deformation temperature in Mg-6Al-1Zn alloy
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作者 Hafiz Muhammad Rehan Tariq Umer Masood Chaudry +3 位作者 Jeong-Rim Lee Nooruddin Ansari Mansoor Ali Tea-Sung Jun 《International Journal of Minerals,Metallurgy and Materials》 2026年第1期242-251,共10页
Understanding the temperature dependent deformation behavior of Mg alloys is crucial for their expanding use in the aerospace sector.This study investigates the deformation mechanisms of hot-rolled AZ61 Mg alloy under... Understanding the temperature dependent deformation behavior of Mg alloys is crucial for their expanding use in the aerospace sector.This study investigates the deformation mechanisms of hot-rolled AZ61 Mg alloy under uniaxial tension along rolling direction(RD)and transverse direction(TD)at-50,25,50,and 150℃.Results reveal a transition from high strength with limited elongation at-50℃ to significant softening and maximum ductility at 150℃.TD samples consistently showed 2%-6%higher strength than RD;however,this yield anisotropy diminished at 150℃ due to the shift from twinning to thermally activated slip and recovery.Fractography indicated a change from semi-brittle to fully ductile fracture with increasing temperature.Electron backscattered diffraction(EBSD)analysis confirmed twinning-driven grain refinement at low temperatures,while deformation at high temperatures involved grain elongation along shear zones,enabling greater strain accommodation before material failure. 展开更多
关键词 Mg alloy deformation temperature twinning dynamics grain refinement dynamic recovery fracture mechanics
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Dynamic psychological vulnerability and adaptation in rheumatoid arthritis:Trajectories,predictors,and interventions
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作者 Xue-Meng Chen Xian Cheng Wei Wu 《World Journal of Psychiatry》 2026年第1期32-46,共15页
Rheumatoid arthritis(RA)patients face significant psychological challenges alongside physical symptoms,necessitating a comprehensive understanding of how psychological vulnerability and adaptation patterns evolve thro... Rheumatoid arthritis(RA)patients face significant psychological challenges alongside physical symptoms,necessitating a comprehensive understanding of how psychological vulnerability and adaptation patterns evolve throughout the disease course.This review examined 95 studies(2000-2025)from PubMed,Web of Science,and CNKI databases including longitudinal cohorts,randomized controlled trials,and mixed-methods research,to characterize the complex interplay between biological,psychological,and social factors affecting RA patients’mental health.Findings revealed three distinct vulnerability trajectories(45%persistently low,30%fluctuating improvement,25%persistently high)and four adaptation stages,with critical intervention periods occurring 3-6 months postdiagnosis and during disease flares.Multiple factors significantly influence psychological outcomes,including gender(females showing 1.8-fold increased risk),age(younger patients experiencing 42%higher vulnerability),pain intensity,inflammatory markers,and neuroendocrine dysregulation(48%showing cortisol rhythm disruption).Early psychological intervention(within 3 months of diagnosis)demonstrated robust benefits,reducing depression incidence by 42%with effects persisting 24-36 months,while different modalities showed complementary advantages:Cognitive behavioral therapy for depression(Cohen’s d=0.68),mindfulness for pain acceptance(38%improvement),and peer support for meaning reconstruction(25.6%increase).These findings underscore the importance of integrating routine psychological assessment into standard RA care,developing stage-appropriate interventions,and advancing research toward personalized biopsychosocial approaches that address the dynamic psychological dimensions of the disease. 展开更多
关键词 Rheumatoid arthritis Psychological vulnerability Disease adaptation ability Dynamic changes Mental health
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Numerical Analysis and Geometric Assessment of Air Layer Distribution in a Ventilated Planing Hull in Calm Water
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作者 Massimiliano Chillemi Filippo Cucinotta Felice Sfravara 《哈尔滨工程大学学报(英文版)》 2026年第1期46-62,共17页
The issue of resistance reduction through hull ventilation is of particular interest in contemporary research.This paper presents multiphase computational fluid dynamics(CFD)simulations with 2-DOF motion of a planing ... The issue of resistance reduction through hull ventilation is of particular interest in contemporary research.This paper presents multiphase computational fluid dynamics(CFD)simulations with 2-DOF motion of a planing hull.The original hull was modified by introducing a step to allow air ventilation.Following an assessment of the hull performance,a simulation campaign in calm water was conducted to characterize the hull at various forward speeds and air insufflation rates for a defined single step geometry.Geometric analysis of the air layer thickness beneath the hull for each simulated condition was performed using a novel method for visualizing local air thickness.Additionally,two new parameters were introduced to understand the influence of spray rails on the air volume beneath the hull and to indicate the primary direction of ventilated air escape.A validation campaign and an assessment of uncertainty of the simulation has been conducted.The features offered by the CFD methodology include the evaluation of the air layer thickness as a function of hull velocity and injection flow rate and the air volume distribution beneath the hull.The air injection velocity can be adjusted across various operating conditions,thereby preventing performance or efficiency loss during navigation.Based on these findings,the study highlights the benefits of air insufflation in reducing hull resistance for high-speed planing vessels.This work lays a robust foundation for future research and new promising topics,as the exploration of air insufflation continues to be a topic of contemporary interest within naval architecture and hydrodynamics. 展开更多
关键词 Computational fluid dynamics Air cavity ships Planing hull HYDRODYNAMICS Maritime sustainability
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Future directions of image-guided thermal ablation in colorectal cancer lung oligometastases
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作者 Yu-Yin Wang Cui-Ping Zhang +3 位作者 Qing-Biao Zhang Xing-Yan Le Jun-Bang Feng Chuan-Ming Li 《World Journal of Gastroenterology》 2026年第2期162-166,共5页
Colorectal cancer(CRC)with lung oligometastases,particularly in the presence of extrapulmonary disease,poses considerable therapeutic challenges in clinical practice.We have carefully studied the multicenter study by ... Colorectal cancer(CRC)with lung oligometastases,particularly in the presence of extrapulmonary disease,poses considerable therapeutic challenges in clinical practice.We have carefully studied the multicenter study by Hu et al,which evaluated the survival outcomes of patients with metastatic CRC who received image-guided thermal ablation(IGTA).These findings provide valuable clinical evidence supporting IGTA as a feasible,minimally invasive approach and underscore the prognostic significance of metastatic distribution.However,the study by Hu et al has several limitations,including that not all pulmonary lesions were pathologically confirmed,postoperative follow-up mainly relied on dynamic contrast-enhanced computed tomography,no comparative analysis was performed with other local treatments,and the impact of other imaging features on efficacy and prognosis was not evaluated.Future studies should include complete pathological confirmation,integrate functional imaging and radiomics,and use prospective multicenter collaboration to optimize patient selection standards for IGTA treatment,strengthen its clinical evidence base,and ultimately promote individualized decision-making for patients with metastatic CRC. 展开更多
关键词 Colorectal cancer Lung oligometastases Extrapulmonary metastases Imageguided thermal ablation Dynamic contrast-enhanced computed tomography Functional imaging
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Lithium-Ion Dynamic Interface Engineering of Nano-Charged Composite Polymer Electrolytes for Solid-State Lithium-Metal Batteries
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作者 Shanshan Lv Jingwen Wang +7 位作者 Yuanming Zhai Yu Chen Jiarui Yang Zhiwei Zhu Rui Peng Xuewei Fu Wei Yang Yu Wang 《Nano-Micro Letters》 2026年第2期288-305,共18页
Composite polymer electrolytes(CPEs)offer a promising solution for all-solid-state lithium-metal batteries(ASSLMBs).However,conventional nanofillers with Lewis-acid-base surfaces make limited contribution to improving... Composite polymer electrolytes(CPEs)offer a promising solution for all-solid-state lithium-metal batteries(ASSLMBs).However,conventional nanofillers with Lewis-acid-base surfaces make limited contribution to improving the overall performance of CPEs due to their difficulty in achieving robust electrochemical and mechanical interfaces simultaneously.Here,by regulating the surface charge characteristics of halloysite nanotube(HNT),we propose a concept of lithium-ion dynamic interface(Li^(+)-DI)engineering in nano-charged CPE(NCCPE).Results show that the surface charge characteristics of HNTs fundamentally change the Li^(+)-DI,and thereof the mechanical and ion-conduction behaviors of the NCCPEs.Particularly,the HNTs with positively charged surface(HNTs+)lead to a higher Li^(+)transference number(0.86)than that of HNTs-(0.73),but a lower toughness(102.13 MJ m^(-3)for HNTs+and 159.69 MJ m^(-3)for HNTs-).Meanwhile,a strong interface compatibilization effect by Li^(+)is observed for especially the HNTs+-involved Li^(+)-DI,which improves the toughness by 2000%compared with the control.Moreover,HNTs+are more effective to weaken the Li^(+)-solvation strength and facilitate the formation of Li F-rich solid-electrolyte interphase of Li metal compared to HNTs-.The resultant Li|NCCPE|LiFePO4cell delivers a capacity of 144.9 m Ah g^(-1)after 400 cycles at 0.5 C and a capacity retention of 78.6%.This study provides deep insights into understanding the roles of surface charges of nanofillers in regulating the mechanical and electrochemical interfaces in ASSLMBs. 展开更多
关键词 Charged nanofillers Nanocomposite polymer electrolyte Dynamic lithium ion interface Solid ion-conductors Solidstate lithium-metal battery
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Mitochondrial dynamics dysfunction and neurodevelopmental disorders:From pathological mechanisms to clinical translation
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作者 Ziqi Yang Yiran Luo +5 位作者 Zaiqi Yang Zheng Liu Meihua Li Xiao Wu Like Chen Wenqiang Xin 《Neural Regeneration Research》 2026年第5期1926-1946,共21页
Mitochondrial dysfunction has emerged as a critical factor in the etiology of various neurodevelopmental disorders, including autism spectrum disorders, attention-deficit/hyperactivity disorder, and Rett syndrome. Alt... Mitochondrial dysfunction has emerged as a critical factor in the etiology of various neurodevelopmental disorders, including autism spectrum disorders, attention-deficit/hyperactivity disorder, and Rett syndrome. Although these conditions differ in clinical presentation, they share fundamental pathological features that may stem from abnormal mitochondrial dynamics and impaired autophagic clearance, which contribute to redox imbalance and oxidative stress in neurons. This review aimed to elucidate the relationship between mitochondrial dynamics dysfunction and neurodevelopmental disorders. Mitochondria are highly dynamic organelles that undergo continuous fusion and fission to meet the substantial energy demands of neural cells. Dysregulation of these processes, as observed in certain neurodevelopmental disorders, causes accumulation of damaged mitochondria, exacerbating oxidative damage and impairing neuronal function. The phosphatase and tensin homolog-induced putative kinase 1/E3 ubiquitin-protein ligase pathway is crucial for mitophagy, the process of selectively removing malfunctioning mitochondria. Mutations in genes encoding mitochondrial fusion proteins have been identified in autism spectrum disorders, linking disruptions in the fusion-fission equilibrium to neurodevelopmental impairments. Additionally, animal models of Rett syndrome have shown pronounced defects in mitophagy, reinforcing the notion that mitochondrial quality control is indispensable for neuronal health. Clinical studies have highlighted the importance of mitochondrial disturbances in neurodevelopmental disorders. In autism spectrum disorders, elevated oxidative stress markers and mitochondrial DNA deletions indicate compromised mitochondrial function. Attention-deficit/hyperactivity disorder has also been associated with cognitive deficits linked to mitochondrial dysfunction and oxidative stress. Moreover, induced pluripotent stem cell models derived from patients with Rett syndrome have shown impaired mitochondrial dynamics and heightened vulnerability to oxidative injury, suggesting the role of defective mitochondrial homeostasis in these disorders. From a translational standpoint, multiple therapeutic approaches targeting mitochondrial pathways show promise. Interventions aimed at preserving normal fusion-fission cycles or enhancing mitophagy can reduce oxidative damage by limiting the accumulation of defective mitochondria. Pharmacological modulation of mitochondrial permeability and upregulation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha, an essential regulator of mitochondrial biogenesis, may also ameliorate cellular energy deficits. Identifying early biomarkers of mitochondrial impairment is crucial for precision medicine, since it can help clinicians tailor interventions to individual patient profiles and improve prognoses. Furthermore, integrating mitochondria-focused strategies with established therapies, such as antioxidants or behavioral interventions, may enhance treatment efficacy and yield better clinical outcomes. Leveraging these pathways could open avenues for regenerative strategies, given the influence of mitochondria on neuronal repair and plasticity. In conclusion, this review indicates mitochondrial homeostasis as a unifying therapeutic axis within neurodevelopmental pathophysiology. Disruptions in mitochondrial dynamics and autophagic clearance converge on oxidative stress, and researchers should prioritize validating these interventions in clinical settings to advance precision medicine and enhance outcomes for individuals affected by neurodevelopmental disorders. 展开更多
关键词 autophagic clearance autism spectrum disorders cellular homeostasis fusion and fission mitochondrial dynamics MITOPHAGY neural regeneration neuronal energy metabolism neurodevelopmental disorders oxidative stress
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Magnetic resonance imaging tracing of superparamagnetic iron oxide nanoparticle-labeled mesenchymal stromal cells for repairing spinal cord injury
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作者 Xiaoli Mai Yuanyuan Xie +12 位作者 Zhichong Wu Junting Zou Jiacheng Du Yunpeng Shen Hao Liu Bo Chen Mengxia Zhu Jiong Shi Yang Chen Bing Zhang Zezhang Zhu Bin Wang Ning Gu 《Neural Regeneration Research》 2026年第5期2031-2039,共9页
Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in hu... Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury. 展开更多
关键词 acute spinal cord injury diffusion tensor imaging dynamic migration mesenchymal stromal cells neural function neuronal regeneration quantitative susceptibility mapping repairability ruicun superparamagnetic iron oxide nanoparticle
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基于YOLOv5的汽车液晶仪表图标符号检测方法研究
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作者 郭健忠 肖庆 +2 位作者 谢斌 闵锐 丁宁 《电子器件》 2025年第4期853-862,共10页
在汽车液晶仪表的自动化测试领域,机器视觉学习取代人工检测液晶仪表已成为趋势。针对现有方法存在检测环境苛刻、准确度低以及通用性差等问题,提出了一种基于YOLOv5的汽车液晶仪表图标符号检测方法,实现对仪表常用指示及报警图标符号... 在汽车液晶仪表的自动化测试领域,机器视觉学习取代人工检测液晶仪表已成为趋势。针对现有方法存在检测环境苛刻、准确度低以及通用性差等问题,提出了一种基于YOLOv5的汽车液晶仪表图标符号检测方法,实现对仪表常用指示及报警图标符号的自动化检测工作。该方法通过在YOLOv5网络模型基础上添加ECA注意力机制以减少图标符号周围冗余信息的干扰、采用轻量级通用上采样算子CARAFE扩大特征图的感受野、采用多尺度检测结构增加小图标符号的检测层、引入Dynamic Head模块提高对图标符号的感知能力,从而提高网络模型的检测准确度;同时使用SIoU Loss作为回归定位损失函数,以加快网络模型的收敛速度。与原始YOLOv5模型进行对比实验,结果显示改进模型在多种类的汽车液晶仪表图标符号检测上表现更好,mAP0.5和mAP0.5:0.95分别提高了3.1%和3.6%,达到了95.9%和76.8%,这为汽车液晶仪表图标符号的自动化检测工作提供了方法上的参考。 展开更多
关键词 YOLOv5 多尺度检测 CARAFE dynamic head 仪表图标检测
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基于YOLOv5s的复杂场景下高效烟火检测算法YOLOv5s-MRD 被引量:3
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作者 侯阳 张琼 +2 位作者 赵紫煊 朱正宇 张晓博 《计算机应用》 北大核心 2025年第4期1317-1324,共8页
现有的烟火检测方法主要依赖员工现场巡视,效率低且实时性差,因此,提出一种基于YOLOv5s的复杂场景下的高效烟火检测算法YOLOv5s-MRD(YOLOv5s-MPDIoU-RevCol-Dyhead)。首先,采用MPDIoU(Maximized Position-Dependent Intersection over U... 现有的烟火检测方法主要依赖员工现场巡视,效率低且实时性差,因此,提出一种基于YOLOv5s的复杂场景下的高效烟火检测算法YOLOv5s-MRD(YOLOv5s-MPDIoU-RevCol-Dyhead)。首先,采用MPDIoU(Maximized Position-Dependent Intersection over Union)方法改进边框损失函数,以适应重叠或非重叠的边界框回归(BBR),从而提高BBR的准确性和效率;其次,利用可逆柱状结构RevCol(Reversible Column)网络模型思想重构YOLOv5s模型的主干网络,使它具有多柱状网络架构,并在模型的不同层之间加入可逆链接,从而最大限度地保持特征信息以提高网络的特征提取能力;最后,引入Dynamic head检测头,以统一尺度感知、空间感知和任务感知,从而在不额外增加计算开销的条件下显著提高目标检测头的准确性和有效性。实验结果表明:在DFS(Data of Fire and Smoke)数据集上,与原始YOLOv5s算法相比,所提算法的平均精度均值(mAP@0.5)提升了9.3%,预测准确率提升了6.6%,召回率提升了13.8%。可见,所提算法能满足当前烟火检测应用场景的要求。 展开更多
关键词 目标检测 RevCol网络 YOLOv5 Dynamic head检测头 MPDIoU 烟火检测
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SD-YOLO:一种多尺度小目标检测算法 被引量:1
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作者 赵滨淋 孙玲 +2 位作者 陈功 钟剑丹 付琳 《电光与控制》 北大核心 2025年第7期21-26,共6页
针对无人机航拍图像中小目标样本数量多且尺度变换范围大导致的漏检和误检现象严重等问题,提出一种基于YOLOv8s改进的小目标检测算法SD-YOLO。首先,使用DCNv2模块对C2f进行重构,使模型能够有效地捕捉目标的细粒度细节,自适应地调整卷积... 针对无人机航拍图像中小目标样本数量多且尺度变换范围大导致的漏检和误检现象严重等问题,提出一种基于YOLOv8s改进的小目标检测算法SD-YOLO。首先,使用DCNv2模块对C2f进行重构,使模型能够有效地捕捉目标的细粒度细节,自适应地调整卷积核的采样位置,从而能够准确地定位目标位置;其次,改进SPD-Conv模块,提升模型捕捉局部特征的能力,从而使模型能够保留更多的空间信息;最后,增加一个小目标检测头,并引入Dynamic head模块,提升模型在多尺度场景下的检测性能。在VisDrone2019数据集上的实验结果显示,SD-YOLO的mAP50为0.495,相较于原始YOLOv8s网络提升了0.1,并且能够保持较高帧率,对多尺度小目标的检测性能有显著提高。 展开更多
关键词 小目标检测 YOLOv8s 细粒度细节 Dynamic head
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一种动态窗口法和人工势场法融合的AGV路径规划算法 被引量:1
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作者 李玉清 梁忠楠 +1 位作者 赵衍昭 周坤 《科学技术与工程》 北大核心 2025年第14期5924-5933,共10页
针对原始动态窗口法(dynamic window approach,DWA)在路径规划中存在的振荡现象,设计了一种改进的DWA路径规划算法,该算法融合了人工势场法。首先,提升了DWA算法的安全性约束,并将原始DWA中的线性障碍物距离评价函数改进为人工势场法中... 针对原始动态窗口法(dynamic window approach,DWA)在路径规划中存在的振荡现象,设计了一种改进的DWA路径规划算法,该算法融合了人工势场法。首先,提升了DWA算法的安全性约束,并将原始DWA中的线性障碍物距离评价函数改进为人工势场法中的非线性障碍物势场函数。其次,将改进的DWA与梯度下降法的平滑A*路径相结合,以解决传统算法全局规划能力不足的问题。最后,通过仿真实验和实物实验验证了算法的可行性。在仿真实验中,与原始算法相比,本文算法在设计的障碍物场景中减少了9.84%的路径长度,运行时间缩短了31.71%,平滑度提升了6.49%。在自动导引车实物实验中,路径长度减少了10.76%,运行时间缩短了13.09%。因此,改进的DWA算法能够生成更平滑的路径、更短的路径长度和更短的运行时间。 展开更多
关键词 自动导引车 路径规划 动态窗口法(dynamic window approach DWA) 人工势场法
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Extraction of symmetry energy coefficient in heavy-ion reactions near the Fermi energies
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作者 冷强钟 曲国峰 +8 位作者 黄宇 张鑫 段茜 陈婉君 林炜平 郑华 任培培 刘星泉 韩纪锋 《四川大学学报(自然科学版)》 北大核心 2025年第1期153-161,共9页
An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.Thi... An improved method is proposed for the extraction of the symmetry energy coefficient relative to the temperature,a_(sym)/T,in the heavy-ion reactions near the Fermi energy region,based on the modified Fisher Model.This method is applied to the primary fragments of antisymmetrized molecular dynamics(AMD)simulations for ^(46)Fe+^(46)Fe,^(40)Ca+^(40)Ca and ^(48)Ca+^(48)Ca at 35 MeV/nucleon,in order to make direct comparison to the results from the K(N,Z)method of Ono et al.In our improved method,the extracted values of a_(sym)/T increase as the size of isotopes increases whereas,in the K(N,Z)method,the results show rather constant behavior.This increase in our result is attributed to the surface contribution of the symmetry energy in finite nuclei.In order to evaluate the surface contribution,the relation a_(sym)/T=[a_(sym)^((V))(1-k_(S/V) A^(-1/3))]/T is applied and k_(S/V)=1.20~1.25 was extracted.This value is smaller than those extracted from the mass table,reflecting the weakened surface contribution at higher temperature regime.Δμ/T,the difference of the neutron-proton chemical potentials relative to the temperature,is also extracted in this method at the same time.The average values of the extractedΔμ/T,Δμ/T show a linear dependence on the proton-neutron a_(sym)metry parameter of the system,δ_(sys),andΔμ/T=(15.1±0.2)δ_(sys)-(0.5±0.1)is obtained. 展开更多
关键词 Heavy-ion reactions Symmetry energy Antisymmetrized molecular dynamics model
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融合激光测高数据的无控GF-7卫星影像矿区DSM改进方法
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作者 张云龙 胡文敏 +3 位作者 魏伟 秦凯 徐嘉兴 张炜 《遥感学报》 北大核心 2025年第9期2700-2713,共14页
针对沟壑发育地表无地面控制点GCPs(Ground Control Points)条件下卫星遥感立体影像地形三维重建精度较低、大面积GCPs采集困难或成本高等问题,本文提出融合卫星激光测高数据的高分七号(GF-7)卫星影像数字表面模型DSM(Digital Surface M... 针对沟壑发育地表无地面控制点GCPs(Ground Control Points)条件下卫星遥感立体影像地形三维重建精度较低、大面积GCPs采集困难或成本高等问题,本文提出融合卫星激光测高数据的高分七号(GF-7)卫星影像数字表面模型DSM(Digital Surface Model)BP神经网络方法。该方法通过建立无控条件下GF-7卫星立体影像生成的DSM、地理位置经度与纬度、地形坡度、地形误差等多因子与激光测高点GEDI(Global Ecosystem Dynamics Investigation)之间的关系,获取融合结果以改进无控条件下地形DSM精度。实验结果表明,沟壑发育地表矿区无控条件下GF-7卫星立体影像生成的DSM高程精度可高达20.49 m,而本文融合生成的DSM平均高程精度为1.63 m,与有控制点条件下地形DSM 1.44 m的高程精度基本相当。本文方法有效改善了沟壑发育地表矿区无控条件下卫星立体影像生成DSM高程精度质量低的问题,为国产高分影像推广应用与高精度地形建模提供新思路。 展开更多
关键词 数字表面模型 地面控制点 神经网络 沟壑发育地表 GF-7卫星立体影像 GEDI(Global Ecosystem Dynamics Investigation)
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基于改进YOLOv8n的松材线虫病疫木检测方法
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作者 王余康 黄雷君 李洋 《林草资源研究》 北大核心 2025年第1期114-125,共12页
松材线虫病对全球松树资源和生态环境造成严重威胁,准确检测疫木对于控制疫情蔓延具有重要意义。借助无人机遥感技术,能够高效获取覆盖广泛、分辨率高的森林影像数据,为松材线虫病疫木检测提供了关键的数据支持。针对复杂森林环境下无... 松材线虫病对全球松树资源和生态环境造成严重威胁,准确检测疫木对于控制疫情蔓延具有重要意义。借助无人机遥感技术,能够高效获取覆盖广泛、分辨率高的森林影像数据,为松材线虫病疫木检测提供了关键的数据支持。针对复杂森林环境下无人机遥感影像中松材线虫病疫木检测识别能力受限的问题,提出一种改进的YOLOv8n检测模型(YOLOv8n-RCD)。使用RepVit作为主干网络,提升特征提取能力;通过引入跨尺度特征融合模块(CCFM),增强模型对多层次特征的提取;采用动态头(Dynamic Head)替换原有检测头,提高模型在复杂背景下的目标识别能力和适应性。结果表明:改进后的YOLOv8n-RCD在精确率(P)、召回率(R)和F1分数上比基准模型(YOLOv8n)分别提升了3.37%、3.00%和3.19%,AP50和AP50-95分别提升了1.93%和1.49%。改进后的模型提升了在复杂森林环境下的识别精度和能力,为松材线虫病疫木的精确化检测和无人机遥感驱动的智能化动态防控提供了有力的技术支持。 展开更多
关键词 目标检测 松材线虫病 YOLOv8n RepVit CCFM Dynamic Head
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改进YOLOv8的铸件多肉缺陷检测
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作者 刘琦 马行 穆春阳 《现代电子技术》 北大核心 2025年第11期131-135,共5页
针对铸造生产过程中铸件表面多肉缺陷数据集少、复杂环境下人工检测困难以及检测效率较低等问题,文中基于YOLOv8提出改进算法。对数据进行增强处理,以便提升模型的鲁棒性,更贴合实际环境;引入残差网络Resnet替换网络主干部分,提高模型... 针对铸造生产过程中铸件表面多肉缺陷数据集少、复杂环境下人工检测困难以及检测效率较低等问题,文中基于YOLOv8提出改进算法。对数据进行增强处理,以便提升模型的鲁棒性,更贴合实际环境;引入残差网络Resnet替换网络主干部分,提高模型提取目标特征的能力;对Neck部分进行重构,避免参数量的增加;在网络的输出末端加入具有注意力机制的Dynamic Head检测头,将模型对目标感知和表达的能力进一步提高;在训练模型能力过程中加入MPDIoU损失函数,强化模型对于目标边框的处理,提高模型对铸件多肉缺陷的识别精准度。实验结果表明,改进的YOLOv8模型在检测铸件多肉缺陷数据集上的mAP相比原模型提升2.2%,提升了小目标识别精度,正确检测率提高了16.1%。 展开更多
关键词 缺陷检测 铸件多肉缺陷 YOLOv8 注意力机制 Resnet Dynamic Head
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基于改进YOLO v8-FDE的大豆田间杂草识别方法
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作者 李孝晖 谭峰 +1 位作者 陈雪 宁韶瞳 《江苏农业科学》 北大核心 2025年第20期202-210,共9页
针对大豆田间杂草识别中存在的背景复杂、识别准确率低、模型参数量大、计算量高以及难以部署到边缘设备等问题,提出一种改进的轻量化YOLO v8-FDE大豆田间杂草识别方法。首先对无人机采集到的杂草图像进行噪声增强、亮度增强、对比度增... 针对大豆田间杂草识别中存在的背景复杂、识别准确率低、模型参数量大、计算量高以及难以部署到边缘设备等问题,提出一种改进的轻量化YOLO v8-FDE大豆田间杂草识别方法。首先对无人机采集到的杂草图像进行噪声增强、亮度增强、对比度增强,提高数据集的丰富度;其次在YOLO v8-Seg实例分割网络的基础上,优化模型架构,使用轻量级网络FasterNet替代主干网络中的C2f模块,以减少计算量和模型参数,引入DynamicHead动态检测头,增强上下文信息融合能力,以支持多尺度目标的识别,通过结合Focal-EIoU损失函数加速模型收敛,提升训练效率和目标定位能力。结果表明,改进后的YOLO v8-FDE模型在检测精度和模型复杂度方面均表现优异;改进模型的平均检测精度(mAP)为98.2%,与原始YOLO v8n-Seg相比仅降低0.5百分点,但模型参数量为2.68 MB,减少21.4%;模型的计算量为6.0GFLOPs,降低53.1%;模型存储大小为5.77 MB,降低11.6%。改进的轻量化YOLO v8-FDE模型在保持较高检测精度的同时降低了模型存储大小、参数量、计算量,期待可为田间杂草识别模型在资源受限的边缘设备上的实际部署提供技术参考。 展开更多
关键词 大豆 杂草识别 实例分割 YOLO v8 FasterNet Dynamic Head Focal-EIoU
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Structural Color Dynamic Graphics Display Based on Microlens Array 被引量:1
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作者 LI Xue-han LIU Ling-zhi +1 位作者 HUANG Min LI Xiu 《印刷与数字媒体技术研究》 北大核心 2025年第2期162-168,共7页
It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be... It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display. 展开更多
关键词 Structural color Microlens array Dynamic graphics display Moirémagnification Optical anti-counterfeiting
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Data driven prediction of fragment velocity distribution under explosive loading conditions 被引量:4
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作者 Donghwan Noh Piemaan Fazily +4 位作者 Songwon Seo Jaekun Lee Seungjae Seo Hoon Huh Jeong Whan Yoon 《Defence Technology(防务技术)》 2025年第1期109-119,共11页
This study presents a machine learning-based method for predicting fragment velocity distribution in warhead fragmentation under explosive loading condition.The fragment resultant velocities are correlated with key de... This study presents a machine learning-based method for predicting fragment velocity distribution in warhead fragmentation under explosive loading condition.The fragment resultant velocities are correlated with key design parameters including casing dimensions and detonation positions.The paper details the finite element analysis for fragmentation,the characterizations of the dynamic hardening and fracture models,the generation of comprehensive datasets,and the training of the ANN model.The results show the influence of casing dimensions on fragment velocity distributions,with the tendencies indicating increased resultant velocity with reduced thickness,increased length and diameter.The model's predictive capability is demonstrated through the accurate predictions for both training and testing datasets,showing its potential for the real-time prediction of fragmentation performance. 展开更多
关键词 Data driven prediction Dynamic fracture model Dynamic hardening model FRAGMENTATION Fragment velocity distribution High strain rate Machine learning
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