期刊文献+
共找到16,543篇文章
< 1 2 250 >
每页显示 20 50 100
Recent advances of transformable nanoparticles for theranostics 被引量:3
1
作者 Kuo Zhang Pei-Pei Yang +2 位作者 Jing-Ping Zhang Lei Wang Hao Wang 《Chinese Chemical Letters》 SCIE CAS CSCD 2017年第9期1808-1816,共9页
In recent years,various transformable nanoparticles(NPs)were successfully prepared and widely utilized for biomedical applications.The sizes,surface charges or morphologies of transformable NPs would affect their be... In recent years,various transformable nanoparticles(NPs)were successfully prepared and widely utilized for biomedical applications.The sizes,surface charges or morphologies of transformable NPs would affect their behavior in physiological/pathological conditions including circulation,penetration,accumulation and retention etc.The other way round,the NPs could be precisely modulated in the specific physiological/pathological condition for precision theranostics of diseases.Herein,we summarized recent advances of transformable NPs for disease diagnostics and therapy.In this review,the transformation of NPs was divided into three groups including changes in size,surface charge and morphology,which was induced by internal stimuli,such as p H,enzyme,receptor or external stimuli,such as light,temperature etc.Moreover,we focused on the characterization of structural transformation in vivo,as well as the transformation-induced biological effects for theranostics of disease. 展开更多
关键词 transformable Nanoparticles Tumor Imaging Therapy
原文传递
Spatiotemporal transformable nano-assembly for on-demand drug delivery to enhance anti-tumor immunotherapy
2
作者 Chenglin Liang Ge Zhang +5 位作者 Linlin Guo Xinyi Ding Heng Yang Hongling Zhang Zhenzhong Zhang Lin Hou 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2024年第1期103-118,共16页
Induction of tumor cell senescence has become a promising strategy for anti-tumor immunotherapy,but fibrotic matrix severely blocks senescence inducers penetration and immune cells infiltration.Herein,we designed a ca... Induction of tumor cell senescence has become a promising strategy for anti-tumor immunotherapy,but fibrotic matrix severely blocks senescence inducers penetration and immune cells infiltration.Herein,we designed a cancer-associated fibroblasts(CAFs)triggered structure-transformable nano-assembly(HSD-P@V),which can directionally deliver valsartan(Val,CAFs regulator)and doxorubicin(DOX,senescence inducer)to the specific targets.In detail,DOX is conjugated with hyaluronic acid(HA)via diselenide bonds(Se-Se)to form HSD micelles,while CAFs-sensitive peptide is grafted onto the HSD to form a hydrophilic polymer,which is coated on Val nanocrystals(VNs)surface for improving the stability and achieving responsive release.Once arriving at tumor microenvironment and touching CAFs,HSD-P@V disintegrates into VNs and HSD micelles due to sensitive peptide detachment.VNs can degrade the extracellularmatrix,leading to the enhanced penetration of HSD.HSD targets tumor cells,releases DOX to induce senescence,and recruits effector immune cells.Furthermore,senescent cells are cleared by the recruited immune cells to finish the integrated anti-tumor therapy.In vitro and in vivo results show that the nanoassembly remarkably inhibits tumor growth as well as lungmetastasis,and extends tumorbearing mice survival.This work provides a promising paradigm of programmed delivering multi-site nanomedicine for cancer immunotherapy. 展开更多
关键词 Cells senescence Tumor stroma Structure transformable Programmed delivery Anti-tumor immunotherapy
暂未订购
Nature and Kinetic Architecture: The Development of a New Type of Transformable Structure for Temporary Applications
3
作者 Maziar Asefi Aysan Foruzandeh 《Journal of Civil Engineering and Architecture》 2011年第6期513-526,共14页
The contemplation of contemporary architectural designs shows an increasing demand for the development of more adaptable, flexible and transformable structures. This type of structures can adapt with different environ... The contemplation of contemporary architectural designs shows an increasing demand for the development of more adaptable, flexible and transformable structures. This type of structures can adapt with different environmental conditions and meet different functions. This can help in reducing environmental waste and pollution associated with many buildings and above all can save on cost and time. Natural systems have inspired human being, since they began to build and design. Architects and designers have utilized nature as one of the main resources of information for the creation of innovative architectural spaces. One of the unique features of natural structures is the way that their components open and close in order to respond to a particular requirement or the environmental changes. This aspect has inspired many designers for the development of transformable architectural structures that can change their shape and geometry to be able to adapt with specific conditions. To make a way toward the design of transformable structure for temporary applications, the authors have developed a new type of adaptable structures according to natural forms. The proposed design applies the transformation principles that exist in potato's flower and the movement mechanisms used in a spider's leg. The design is able to fit to different topographies and have a potential to be folded to a very compact state in a very short period of time. The detailed design and the different configurations of the system applications will be presented in this paper. The result of the study shows that using modular triangular plates can create a changeable module that is not only able to respond to different functions and environmental changes but it is also able to shape different configuration to be able to respond to different user's ambitions. The compactability of this structure into 1/3 of its base dimensions; makes its transportation fast and with minimum costs. These capabilities make this structure suitable for temporary buildings such as exhibitions, temporary settlements or hospital in damaged areas. 展开更多
关键词 Flexible changeable transformable temporary structure natural lessons.
在线阅读 下载PDF
Geometric Study of Two-Dimension Stellated Reentrant Auxetic Structures to Transformable Architecture
4
作者 MªDoloresÁlvarez Elipe 《Journal of Architectural Environment & Structural Engineering Research》 2023年第1期17-24,共8页
Transformable architecture is totally linked to the study and knowledge of geometry.There are some materials in nature,whose geometric invariants establish equivalent structural behavior regarding the scalar transform... Transformable architecture is totally linked to the study and knowledge of geometry.There are some materials in nature,whose geometric invariants establish equivalent structural behavior regarding the scalar transformations,developing different spatial typologies according to dimensional variation.Auxetic materials are characterized by their negative Poisson’s ratio.They can change their geometric configuration from a line to a surface,and from a surface to a volume or spatial framework.This paper is based on establishing and comparing those stellated reentrant auxetic geometries to be able to build new spaces defined by their capacity for architectural transformation,studying analytically geometric properties of stellated reentrant auxetic structures that,from the molecular to the macroscopic level,can be part of the architecture construction.In this investigation,a comparative study by means of CAD of stellated reentrant auxetic patterns has been realized.A Computer-Aided Design study of stellated reentrant auxetic structures will be realized to use them in architecture.The geometric behavior of the different stellated reentrant auxetic patterns is analyzed from the developed study to generate a systematic comparison,evaluating properties of these forms,such as their maximum achievable area reductions in relation to the total length of bars of the structure,in order to obtain a growth factor. 展开更多
关键词 transformable ARCHITECTURE GEOMETRY AUXETIC Stellated REENTRANT CAD Growth factor
在线阅读 下载PDF
A Sub-Nanostructural Transformable Nanozyme for Tumor Photocatalytic Therapy 被引量:6
5
作者 Xi Hu Nan Wang +8 位作者 Xia Guo Zeyu Liang Heng Sun Hongwei Liao Fan Xia Yunan Guan Jiyoung Lee Daishun Ling Fangyuan Li 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第6期282-293,共12页
The structural change-mediated catalytic activity regulation plays a significant role in the biological functions of natural enzymes.However,there is virtually no artificial nanozyme reported that can achieve natural ... The structural change-mediated catalytic activity regulation plays a significant role in the biological functions of natural enzymes.However,there is virtually no artificial nanozyme reported that can achieve natural enzyme-like stringent spatiotemporal structure-based catalytic activity regulation.Here,we report a subnanostructural transformable gold@ceria(STGC-PEG)nanozyme that performs tunable catalytic activities via near-infrared(NIR)light-mediated sub-nanostructural transformation.The gold core in STGC-PEG can generate energetic hot electrons upon NIR irradiation,wherein an internal sub-nanostructural transformation is initiated by the conversion between CeO;and electron-rich state of CeO;-x,and active oxygen vacancies generation via the hot-electron injection.Interestingly,the sub-nanostructural transformation of STGC-PEG enhances peroxidase-like activity and unprecedentedly activates plasmon-promoted oxidase-like activity,allowing highly efficient low-power NIR light(50 m W cm;)-activated photocatalytic therapy of tumors.Our atomic-level design and fabrication provide a platform to precisely regulate the catalytic activities of nanozymes via a light-mediated sub-nanostructural transformation,approaching natural enzyme-like activity control in complex living systems. 展开更多
关键词 Nanozymes Sub-nanostructural transformation Catalytic activity Reactive oxygen species Photocatalytic therapy
在线阅读 下载PDF
Effects of Al addition and cryogenic cyclic treatment on impact toughness of phase-transformable Ti-based bulk metallic glass composites 被引量:1
6
作者 Tingyi Yan Long Zhang +6 位作者 R.Lakshmi Narayan Jingyu Pang Yi Wu Huameng Fu Hong Li Upadrasta Ramamurty Haifeng Zhang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2023年第9期210-220,共11页
Developing bulk metallic glass composites(BMGCs)with high toughness is vital for their practical application.However,the influence of different microstructures on the impact toughness of BMGCs is still unclear.The eff... Developing bulk metallic glass composites(BMGCs)with high toughness is vital for their practical application.However,the influence of different microstructures on the impact toughness of BMGCs is still unclear.The effects of Al addition and cryogenic cyclic treatment(CCT)on the Charpy impact toughness,a K,at 298 and 77 K of a series of phase-transformable BMGCs are investigated in this work.It is found that deformation-induced martensitic transformation(DIMT)of theβ-Ti dendrites is the dominant toughening mechanism in the phase-transformable BMGCs at 298 K,but at 77 K,the toughness of BMGCs is primarily determined by the intrinsic toughness of the glass matrix.The addition of Al can moderately tune theβ-Ti phase stability,which then affects the amount of DIMT and impact toughness of the BMGCs at 298 K.However,at 77 K,Al addition causes a monotonic decrease in the toughness of the BMGCs due to the embrittlement of the glass matrix.It is found that CCT can effectively rejuvenate the phase-transformable BMGCs,which results in an enhanced impact toughness at 298 K.However,the toughness at 77 K monotonously decreases with increasing the number of CCT cycles,suggesting that the rejuvenation of the glass matrix affects the toughness at both 298 and 77 K of BMGCs,but in dramatically different ways.These findings reveal the influence of microstructures and CCT on the impact toughness of BMGCs and provide insights that could be useful for designing tougher BMGs and BMGCs. 展开更多
关键词 Bulk metallic glass composites Charpy impact toughness Deformation-induced martensitic transformation METASTABILITY Thermal cycling rejuvenation
原文传递
Elite,transformable haploid inducers in maize
7
作者 Brent Delzer Dawei Liang +22 位作者 David Szwerdszarf Isadora Rodriguez Gonzalo Mardones Sivamani Elumalai Francine Johnson Samson Nalapalli Rachel Egger Erin Burch Kerry Meier Juan Wei Xiujuan Zhang Huaping Gui Huaibing Jin Huan Guo Kun Yu Yubo Liu Becky Breitinger Ana Poets Jason Nichols Wan Shi David Skibbe Qiudeng Que Timothy Kelliher 《The Crop Journal》 SCIE CSCD 2024年第1期314-319,共6页
The introduction of alleles into commercial crop breeding pipelines is both time consuming and costly.Two technologies that are disrupting traditional breeding processes are doubled haploid(DH)breeding and genome edit... The introduction of alleles into commercial crop breeding pipelines is both time consuming and costly.Two technologies that are disrupting traditional breeding processes are doubled haploid(DH)breeding and genome editing(GE).Recently,these techniques were combined into a GE trait delivery system called HI-Edit(Haploid Inducer-Edit).In HI-Edit,the pollen of a haploid inducer line is reprogrammed to deliver GE traits to any variety,obviating recurrent selection.For HI-Edit to operate at scale,an efficient transformable HI line is needed,but most maize varieties are recalcitrant to transformation,and haploid inducers are especially difficult to transform given their aberrant reproductive behaviors.Leveraging marker assisted selection and a three-tiered testing scheme,we report the development of new Iodent and Stiff Stalk maize germplasm that are transformable,have high haploid induction rates,and exhibit a robust,genetically-dominant anthocyanin native trait that may be used for rapid haploid identification.We show that transformation of these elite‘‘HI-Edit”lines is enhanced using the BABYBOOM and WUSCHEL morphogenetic factors.Finally,we evaluate the HI-Edit performance of one of the lines against both Stiff Stalk and non-Stiff Stalk testers.The strategy and results of this study should facilitate the development of commercially scalable HI-Edit systems in diverse crops. 展开更多
关键词 Zea mays L Doubled haploids TRANSFORMATION Genome editing QTL
在线阅读 下载PDF
Transformable carbon nanotube network-reinforced hydrogels and organogels for phase change cold storage
8
作者 Qi Wang Nuo Shang +5 位作者 Lei Han Ziming Ye Meng Li Xiaobing Kong Zhifan Jiang Anyuan Cao 《Nano Research》 2026年第2期972-984,共13页
Water,salt solution,and many conventional organic solvents exhibit melting temperatures nearly or well below zero degree,and functional phase change composites based on these components will be useful in energy and en... Water,salt solution,and many conventional organic solvents exhibit melting temperatures nearly or well below zero degree,and functional phase change composites based on these components will be useful in energy and environmental areas.Here,we report the design and fabrication of a series of composite hydrogels and organogels consisting of water,NaCl/water eutectic solution,n-undecane,and n-heptanol held by a built-in carbon nanotube(CNT)-polymer skeleton,respectively.We adopt an initially uniform yet transformable CNT network to mix with gel precursors and obtain densified CNT-reinforced pore walls by in situgelation.These composite gels realized solid-liquid phase transition in temperatures ranging from−10 to−36℃,with reduced supercooling,large enthalpy(120 to 200 J/g),enhanced structural stability and anti-leakage property,and the effects of CNTs on thermal and mechanical properties are investigated systematically.We demonstrate that by wrapping the composite gels around pipe models with cold liquid flow,the temperature increase process could be substantially prolonged,owing to efficient latent heat release during phase change.Our CNT-reinforced hydrogels and organogels,made by a general,facile approach,have many potential applications as cold energy storage and transformation media in liquefied natural gas industry,food,and biomedical fields. 展开更多
关键词 carbon nanotube transformable network phase change composite cold storage HYDROGEL ORGANOGEL
原文传递
NIR light-driven transformable liquid metal-based nanovaccines restrain postoperative colorectal cancer recurrence
9
作者 Zheng Dai Feng Liu +8 位作者 Miaodeng Liu Yuqi Song Hongyan Zhang Cheng Zhou Wenyu Liu Xiaoqiong Li Guobin Wang Lin Wang Zheng Wang 《Bioactive Materials》 2025年第9期774-786,共13页
Cancer vaccines mount specific immune memory responses and hold great potential in suppressing postoperative colorectal cancer(CRC)recurrence.However,undesired lymph node trafficking and antigen cross-presentation ham... Cancer vaccines mount specific immune memory responses and hold great potential in suppressing postoperative colorectal cancer(CRC)recurrence.However,undesired lymph node trafficking and antigen cross-presentation hamper clinical translation of nanovaccines.Here,we propose a controllable transformable nanovaccine grounded on thermal fusion feature of liquid metal(LM)nanoparticles against postoperative CRC recurrence.After draining to lymph nodes,LM-based nanovaccines(LMVs)aggregate and transform from spheres to fusiform sharp under NIR irradiation,conducive to cytoplasmic delivery of LMVs and subsequent antigen crosspresentation.Benefitting from the morphology transformation,LMVs prolong the retention of loaded vaccine molecules in lymph nodes,resulting in satisfactory dendritic cell(DC)recognition and maturation.Such dual effects of transformable LMVs efficiently activate DCs and cytotoxic CD8^(+)T cells,mediating strong systemic immune responses against local recurrence.Moreover,the transformable LMVs can induce potent specific im-mune memory,which is pivotal for eradicating metachronous liver and lung metastasis.This study provides a newly NIR light-regulated postoperative CRC prevention approach. 展开更多
关键词 Colorectal cancer Postoperative recurrence Liquid metal transformable nanovaccine IMMUNOTHERAPY
原文传递
深度学习在细胞图像自动分割中的应用与进展 被引量:1
10
作者 王旭 王晓燕 +3 位作者 郭英慧 蔡肖红 刘艳艳 张文凯 《计算机工程与应用》 北大核心 2026年第2期73-91,共19页
细胞分割研究对于细胞形态学分析、疾病早期诊断、药物筛选以及个性化医疗具有重要意义。细胞图像分割作为一种核心任务,旨在从复杂的生物图像中提取细胞边界和结构,支持疾病诊断和研究。因此,对细胞进行精确分割是解决细胞形态学分析... 细胞分割研究对于细胞形态学分析、疾病早期诊断、药物筛选以及个性化医疗具有重要意义。细胞图像分割作为一种核心任务,旨在从复杂的生物图像中提取细胞边界和结构,支持疾病诊断和研究。因此,对细胞进行精确分割是解决细胞形态学分析、肿瘤检测以及药物筛选等生物医学问题的首要任务。深度学习以其良好的特征提取和自适应学习能力,近年来成为细胞图像自动分割领域的重要技术手段。为推动细胞图像分割研究,在介绍常用细胞图像分割性能评价指标的基础上,梳理了CNN、U-Net、Mask R-CNN、GAN、Transformer、GNN、弱监督学习、迁移学习和视觉大模型以及混合架构在细胞图像分割中的应用,并通过对各模型优缺点进行对比分析,明确了当前研究中存在的主要问题,并展望了未来的研究方向。 展开更多
关键词 细胞分割 深度学习 TRANSFORMER 弱监督学习 混合架构
在线阅读 下载PDF
基于线性注意和类别关联特征学习的在线动作检测 被引量:1
11
作者 詹永照 孙慧敏 +1 位作者 夏惠芬 任晓鹏 《江苏大学学报(自然科学版)》 北大核心 2026年第1期39-47,63,共10页
为了在在线动作检测中充分合理利用动作的上下文特征、与类别关联的特征和预测的未来特征快速检测相应动作,提出基于线性注意和类别关联特征学习的在线动作检测方法.该方法改进了Transformer构架,采用哈达玛积的轻型线性自注意实现Trans... 为了在在线动作检测中充分合理利用动作的上下文特征、与类别关联的特征和预测的未来特征快速检测相应动作,提出基于线性注意和类别关联特征学习的在线动作检测方法.该方法改进了Transformer构架,采用哈达玛积的轻型线性自注意实现Transformer视频上下文特征学习,以减少计算开销;其次对训练样本动作特征进行聚类,将视频序列上下文特征与动作类别特征进行关联学习,有效获得与类别关联的特征表达;最后融合动作的上下文特征、与类别关联的特征和预测的未来特征检测相应时刻动作,以提升动作鉴别性.在典型数据集上进行性能试验,完成了超参取值分析,对比了不同方法的工作精度和运行效率.给出了消融试验和可视化分析.结果表明:在Thumos14(TSN-Anet)、Thumos14(TSN-Kinetics)和HDD数据集上,所提出方法的mAP比Colar方法分别提高了0.2、0.5、0.2百分点,可见新方法优于目前较先进的Colar方法. 展开更多
关键词 在线动作检测 深度学习 注意力机制 编码 上下文特征 TRANSFORMER 类别关联特征学习
在线阅读 下载PDF
基于改进自编码器和TFT的发动机剩余寿命预测模型 被引量:1
12
作者 谭娜 郭嘉玺 +3 位作者 李耀华 石瑞勃 黄金煜昊 雷欣然 《航空动力学报》 北大核心 2026年第2期144-155,共12页
针对航空发动机多源传感器数据在时变工况下退化特征难表征的问题,提出融合改进型卷积自编码器与temporal fusion transformer(TFT)解码器的预测模型,通过多尺度时空特征融合提升了剩余寿命单点预测精度与时变不确定性量化能力。改进的... 针对航空发动机多源传感器数据在时变工况下退化特征难表征的问题,提出融合改进型卷积自编码器与temporal fusion transformer(TFT)解码器的预测模型,通过多尺度时空特征融合提升了剩余寿命单点预测精度与时变不确定性量化能力。改进的卷积自编码器利用其多尺度卷积单元(MSCU)从多维传感器时序数据中提取不同尺度下的特征信息,灵活捕获序列中信息间的局部依赖关系,同时避免了信息丢失问题。TFT解码器通过特征选择模块和多头注意力机制有效捕捉了数据中的全局依赖关系,并通过这些机制揭示了特征的重要性,从而提供了对数据特征影响程度的解释。采用公开数据集进行实验验证,与先进预测模型的比较分析表明,MS1DCAE_TFT模型在FD001与FD003数据集上的方均根误差和分数指标至少提高了0.2%和65.5%,同时分位数回归预测了其寿命区间进行了不确定性量化,可为发动机剩余寿命预测提供可靠的解决方案。 展开更多
关键词 不确定性量化 多尺度卷积单元 temporal fusion transformers解码器 剩余寿命预测 分位数回归
原文传递
基于图像匹配的高空大斜视无源目标定位
13
作者 贾平 李昌灏 +3 位作者 孙辉 宋悦铭 祃卓荦 徐芳 《光学精密工程》 北大核心 2026年第1期124-138,共15页
提出一种基于图像匹配的无源定位方法,通过引入基于Transformer的特征增强与MiHo聚类筛选的两步匹配策略,减轻了高空大斜视条件下传统无源定位算法因微小角度误差导致的定位精度下降程度。根据粗定位结果与飞行参数对航拍图像进行近似... 提出一种基于图像匹配的无源定位方法,通过引入基于Transformer的特征增强与MiHo聚类筛选的两步匹配策略,减轻了高空大斜视条件下传统无源定位算法因微小角度误差导致的定位精度下降程度。根据粗定位结果与飞行参数对航拍图像进行近似正射变换,并截取对应区域的卫星图像。采用RepVGG提取图像粗特征,通过互最近邻实现初步匹配,并结合MiHo与归一化互相关(Normalized Cross Correlation,NCC)筛选匹配点对。最后,借助Transformer模块完成精细化匹配,再根据精匹配结果构建角度误差修正矩阵,多次迭代修正系统误差。实验结果表明,所提方法的定位精度较传统方法有较大幅度提升,在典型应用场景下提升约70%,在斜距90 km的情况下,定位精度可维持在120 m左右。该方法突破了传统无源定位对角度精度的高度依赖,验证了基于图像匹配的无源定位路径的可行性与有效性。 展开更多
关键词 图像匹配 目标定位 航空光电系统 无源定位 大斜视 TRANSFORMER
在线阅读 下载PDF
基于双重并行任务的无人机小目标两阶段检测方法
14
作者 杨艺 朱江睿 +3 位作者 王科平 张高鹏 钱伟 王田 《模式识别与人工智能》 北大核心 2026年第1期31-51,共21页
目标在图像中的尺寸过小是无人机目标检测面临的主要挑战之一,特别是当无人机飞行高度较高且成像分辨率较低时,小目标特征极易在深度神经网络的深层特征中弥散.为此,文中提出基于双重并行任务的无人机小目标两阶段检测方法,并行任务包... 目标在图像中的尺寸过小是无人机目标检测面临的主要挑战之一,特别是当无人机飞行高度较高且成像分辨率较低时,小目标特征极易在深度神经网络的深层特征中弥散.为此,文中提出基于双重并行任务的无人机小目标两阶段检测方法,并行任务包含小目标检测任务与超分辨率重建任务.在超分辨率重建任务分支中,构建空间先验模块和窗口注意力引导模块.小目标检测任务分支以Swin Transformer为基础,并且分别由空间先验模块和窗口注意力引导模块进行浅层特征的空间信息和深层特征的注意力的超分辨率重建.两阶段检测方法分为训练阶段和推理阶段.在训练阶段,超分辨率重建任务分支均以高分辨率特征为标签,从而增强小目标检测任务分支对细节特征的提取能力.在推理阶段,仅保留小目标检测任务分支,可提升方法的推理速度,降低资源开销.在公共数据集VisDrone和自制无人机数据集JZ-UAV上的实验表明,文中方法识别精度较高. 展开更多
关键词 无人机(UAV) Swin TRANSFORMER 小目标检测 超分辨率重建
在线阅读 下载PDF
面向遥感图像超分辨率重建的跨尺度余弦注意力网络
15
作者 李智杰 宋易宸 +3 位作者 李昌华 董玮 张颉 介军 《计算机工程与应用》 北大核心 2026年第1期285-296,共12页
为了解决现有遥感图像超分辨率网络无法充分利用跨尺度特征、参数过多和计算量大的问题,提出一种面向遥感图像超分辨率重建的跨尺度余弦注意力网络。通过引入特征蒸馏机制设计了一种级联特征蒸馏块,用来提取具有不同感知场和高频信息的... 为了解决现有遥感图像超分辨率网络无法充分利用跨尺度特征、参数过多和计算量大的问题,提出一种面向遥感图像超分辨率重建的跨尺度余弦注意力网络。通过引入特征蒸馏机制设计了一种级联特征蒸馏块,用来提取具有不同感知场和高频信息的更丰富的区域特征,同时保持模型轻量化。在级联特征蒸馏块中嵌入一种多分支空间注意力模块以进一步提升网络对关键空间信息的捕捉能力。此外,提出的跨尺度余弦注意力层可以在不增加计算复杂度的情况下有效计算高维和低维特征之间的相关性,从而增强模型对不同尺度特征的处理能力,而且其中的高效余弦自注意力机制解决了网络注意力被特定像素支配的问题,增强网络关注更多特征的能力。在UC Merced和AID数据集上的实验结果表明,所提算法与当前主流的超分辨率重建算法相比以相对较低的计算成本获得了更好的峰值信噪比和结构相似度,重建后的图像恢复了更多的纹理细节信息,验证了所提网络可以在较好地平衡模型轻量化的同时提升超分辨率重建性能。 展开更多
关键词 遥感图像 超分辨率重建 TRANSFORMER 轻量级 跨尺度
在线阅读 下载PDF
计及预案式失配冲击的响应驱动频率稳定紧急切负荷策略
16
作者 孙正龙 刘勇 +5 位作者 陈威翰 章锐 刘铖 华文 张程铭 蔡国伟 《电力系统保护与控制》 北大核心 2026年第1期117-129,共13页
在新型电力系统复杂工况下,以策略表为主体、通过“离线仿真、在线匹配”的预案式频率稳定控制方案存在较高失配风险,甚至因调控失当引发二次冲击,严重威胁电力系统的安全稳定运行。提出一种计及预案式失配冲击的响应驱动频率稳定紧急... 在新型电力系统复杂工况下,以策略表为主体、通过“离线仿真、在线匹配”的预案式频率稳定控制方案存在较高失配风险,甚至因调控失当引发二次冲击,严重威胁电力系统的安全稳定运行。提出一种计及预案式失配冲击的响应驱动频率稳定紧急切负荷策略。该策略动作在预案式控制之后,是对预案式控制的有益补充,能够有效提升系统频率稳定性。首先建立了基于系统频率响应(system frequency response,SFR)模型辨识的频率稳定切负荷量计算方法。提出了基于频率稀疏量测的SFR模型辨识方法,在此基础上建立了含稳定控制的SFR模型,根据频率稳定控制目标迭代求解切负荷量。其次,建立了基于Transformer网络的频率控制敏感点挖掘模型,通过分析关键发电机母线节点频率时序值和频率控制敏感点的映射关系,实现响应驱动的频率控制敏感点在线挖掘。最后,按照敏感点排序快速分配控制措施总量,构建频率稳定紧急控制方案。在某实际交直流混联万节点仿真系统验证了所提方法的有效性。 展开更多
关键词 预案式控制 频率稳定 紧急控制 频率响应模型 TRANSFORMER
在线阅读 下载PDF
基于深度神经网络的声波远探测成像图像解释生成方法
17
作者 吴兴能 唐保勇 +6 位作者 张承森 罗生强 郝志强 黄若坤 段文星 陈旭 鲁明宇 《大庆石油地质与开发》 北大核心 2026年第2期131-141,共11页
声波远探测成像技术作为一种“透过井、向远看”的测井利器,近年来在碳酸盐岩裂缝及缝洞探测等领域中发挥着重要作用。然而,由于声波远探测成像解释存在多解性,并且对解释人员的专业背景要求较高,在一定程度上限制了该技术的进一步应用... 声波远探测成像技术作为一种“透过井、向远看”的测井利器,近年来在碳酸盐岩裂缝及缝洞探测等领域中发挥着重要作用。然而,由于声波远探测成像解释存在多解性,并且对解释人员的专业背景要求较高,在一定程度上限制了该技术的进一步应用。提出了一种基于深度神经网络Transformer架构的声波远探测成像图像自动解释生成方法(CNN):针对声波远探测图像特征提取不准确的问题,该方法有效实现了声波远探测成像的自动化解释。首先通过卷积神经网络捕获图像的视觉特征;然后利用Transformer编码器捕捉图像的长距离依赖关系;其次,引入跨模态特征融合模块,增强模型在图像与文本特征之间的映射关系捕捉能力;然后,通过类别记忆特征矩阵学习不同类型的解释报告特征,进一步优化模型的解释效果;最后,将相同种类的文本向量与文本序列进行融合,最终获得能够准确描述井旁地质异常体的地质解释结论。通过现场实例对比分析声波远探测热图成像结果与酸化压裂曲线,验证了该方法的有效性,为大规模成像样本的训练奠定了基础。研究成果为测井图像解释(如电成像、声波远探测成像等)提供了新的研究思路,并具有广泛的应用前景。 展开更多
关键词 声波远探测 深度神经网络 Transformer网络 解释生成
在线阅读 下载PDF
用于低剂量CT图像降噪的多路特征生成对抗网络
18
作者 王丽芳 任文婧 +2 位作者 郭晓东 张荣国 胡立华 《计算机应用》 北大核心 2026年第1期270-279,共10页
近些年,把生成对抗网络(GAN)应用于低剂量计算机断层扫描(LDCT)图像降噪取得了显著进展。然而,现有方法存在对复杂噪声分布建模能力不足以及结构细节保留能力有限等问题。因此,提出一种用于LDCT图像降噪的多路特征GAN——Trident GAN。... 近些年,把生成对抗网络(GAN)应用于低剂量计算机断层扫描(LDCT)图像降噪取得了显著进展。然而,现有方法存在对复杂噪声分布建模能力不足以及结构细节保留能力有限等问题。因此,提出一种用于LDCT图像降噪的多路特征GAN——Trident GAN。首先,设计特征引导生成器Trident Uformer,通过在U-Net结构的瓶颈层增加特征聚合注意力(FPA)模块解决U型结构空间分辨率较低的问题;其次,设计多路特征提取子模块Trident Block,并在3个分支中分别引入局部细节增强模块(LDEB)提取细节特征,轻量通道注意力模块(LCAB)增强通道特征,以及空间交互注意力模块(SIAB)获得重要空间特征;在SIAB中采用多级交互式注意力函数和评估机制设计空间上下文注意力机制(SCAM),解决单一注意力受限的问题;最后,设计多特征融合(MFF)模块来在三分支末端进行特征聚合,并对局部细节信息和全局语义信息进行建模,解决不同层次之间细节不连续的问题。此外,利用多尺度金字塔判别器(MSPD)在不同维度下检查生成结果的质量,指导具有全局一致性图像的生成。实验结果表明,在Mayo和Piglet数据集上,Trident GAN的平均峰值信噪比(PSNR)和结构相似性(SSIM)分别达到了31.5193 dB/0.8830和33.6331 dB/0.9478,与高频敏感GAN(HFSGAN)相比,参数量降低75.58%,测试时间缩短36.36%。可见,与HFSGAN等方法相比,Trident GAN可在较少的计算负荷下提高了图像质量。 展开更多
关键词 低剂量计算机断层扫描 图像降噪 注意力机制 TRANSFORMER 生成对抗网络
在线阅读 下载PDF
一种面向地图综合建筑多边形化简的Transformer模型
19
作者 刘鹏程 成晓强 +2 位作者 肖天元 杨敏 艾廷华 《测绘学报》 北大核心 2026年第1期124-137,共14页
针对地图综合中建筑多边形化简方法依赖人工规则、自动化程度低且难以利用已有化简成果的问题,本文提出了一种基于Transformer机制的建筑多边形化简模型。该模型首先把建筑多边形映射至一定范围的网格空间,将建筑多边形的坐标串表达为... 针对地图综合中建筑多边形化简方法依赖人工规则、自动化程度低且难以利用已有化简成果的问题,本文提出了一种基于Transformer机制的建筑多边形化简模型。该模型首先把建筑多边形映射至一定范围的网格空间,将建筑多边形的坐标串表达为网格序列,从而获取建筑多边形化简前后的Token序列,构建出建筑多边形化简样本对数据;随后采用Transformer架构建立模型,基于样本数据利用模型的掩码自注意力机制学习点序列之间的依赖关系,最终逐点生成新的简化多边形,从而实现建筑多边形的化简。在训练过程中,模型使用结构化的样本数据,设计了忽略特定索引的交叉熵损失函数以提升化简质量。试验设计包括主试验与泛化验证两部分。主试验基于洛杉矶1∶2000建筑数据集,分别采用0.2、0.3和0.5 mm 3种网格尺寸对多边形进行编码,实现了目标比例尺为1∶5000与1∶10000的化简。试验结果表明,在0.3 mm的网格尺寸下模型性能最优,验证集上的化简结果与人工标注的一致率超过92.0%,且针对北京部分区域的建筑多边形数据的泛化试验验证了模型的迁移能力;与LSTM模型的对比分析显示,在参数规模相近的条件下,LSTM模型无法形成有效收敛,并生成可用结果。本文证实了Transformer在处理空间几何序列任务中的潜力,且能够有效复用已有化简样本,为智能建筑多边形化简提供了具有工程实用价值的途径。 展开更多
关键词 地图综合 建筑多边形化简 TOKENIZATION Transformer模型 上下文工程
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部