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Precipitation behavior of S' phase in rapid cold punched Al−Cu−Mg alloy
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作者 Ze-yi HU Pu-yu LI +4 位作者 Cai-he FAN Shuai WU Yi-ling LU Yin-chun XIAO Ling OU 《Transactions of Nonferrous Metals Society of China》 2026年第1期68-79,共12页
The evolution of the S'precipitate in Al−Cu−Mg alloy was investigated using transmission electron microscopy(TEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF−STEM),molecular dynam... The evolution of the S'precipitate in Al−Cu−Mg alloy was investigated using transmission electron microscopy(TEM),high-angle annular dark-field scanning transmission electron microscopy(HAADF−STEM),molecular dynamics(MD)simulations,and other analytical techniques.The precipitation behavior during different aging stages of the supersaturated solid solution formed after rapid cold punching was focused,which induces rapid dissolution of precipitates.The findings reveal that the precipitation sequence is significantly influenced by aging temperature.At higher aging temperatures,which mitigate lattice distortion in the matrix,the precipitation sequence follows the conventional path.Conversely,at lower aging temperatures,where lattice distortion persists,the sequence deviates,suppressing the formation of Guinier−Preston−Bagaryatsky(GPB)zones.MD simulations confirm that the variations in solute atom diffusion rates at different aging temperatures lead to the differences in the S'phase precipitation sequence. 展开更多
关键词 Al−Cu−Mg alloy aging treatment S'phase evolution rapid cold punching molecular dynamics simulations
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Manual Bowman-stroma onlay transplant for the treatment of symptoms post-radial keratotomy:proof of concept and preliminary results
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作者 Abdo Karim Tourkmani Jorge L.Alio del Barrio +1 位作者 Hao Zhang Jorge L.Alio 《International Journal of Ophthalmology(English edition)》 2026年第1期181-184,共4页
AIM:To describe the technique and the outcomes of manual Bowman layer and stroma transplant-onlay(BLST-o)for 2 cases of radial keratotomy(RK).METHODS:Two patients with visual fluctuations and corneal irregularity due ... AIM:To describe the technique and the outcomes of manual Bowman layer and stroma transplant-onlay(BLST-o)for 2 cases of radial keratotomy(RK).METHODS:Two patients with visual fluctuations and corneal irregularity due to RK were offered manual BLST-o as an alternative to penetrating keratoplasty(PKP).Visual acuity,refraction,corneal topography,corneal aberrometry,and corneal optical coherence tomography(OCT)pre-and postoperative were analyzed.Histology was obtained for 1 case.RESULTS:Both patients had corneal anatomical and morphological improvement,with elimination of the visual fluctuations.In one case,a subsequent excimer laser treatment improved corneal shape further,thus improving vision.The other case,whereas initially improved,developed epithelial ingrowth following suture removal.The latter was explanted and had a xenogeneic implant.The explanted sample was sent for histology,showing a viable graft of Bowman layer and anterior stroma.CONCLUSION:Manual BLST-o is a potential option for the management of symptoms post RK.These grafts may facilitate subsequent treatments such as laser corrections,and may not preclude from other interventions after explantation. 展开更多
关键词 radial keratotomy Bowman layer transplant Bowman layer and stroma transplant
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文化遗产数字化保护与应用研究综述 被引量:13
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作者 耿国华 高健 +7 位作者 汤汶 张敏 曾升 高宏娟 王小凤 许阳 张雨禾 周明全 《西北大学学报(自然科学版)》 北大核心 2025年第1期1-22,共22页
中国拥有丰富多样的物质与非物质文化遗产,利用数字化技术进行文化遗产的建模、保护与展示,已成为文化遗产保护领域以及计算机图形学、计算机视觉等相关领域的研究热点。西北大学文化遗产数字化国家地方联合工程研究中心主要在三代文物... 中国拥有丰富多样的物质与非物质文化遗产,利用数字化技术进行文化遗产的建模、保护与展示,已成为文化遗产保护领域以及计算机图形学、计算机视觉等相关领域的研究热点。西北大学文化遗产数字化国家地方联合工程研究中心主要在三代文物采集建模设备、智慧博物馆建设、陶瓷器文物虚拟复原、古代人物面貌复原以及秦腔的智能媒体融合全息展演5个方面展开研究。然而,由于物质文化遗产与非物质文化遗产的本质不同,在建模方法、修复保护技术以及展示形式方面遇到诸多挑战:①现有文物数字化建模设备效率不高,且需要大量人工干预;②文物种类繁多、特征复杂、形态各异、语义丰富,需要开发适合中国文物的知识抽取和知识图谱构建方法,以实现高效的文物组织与展示;③对破损文物碎片的形状表示、描述方法以及自动重组的研究;④古代人物面貌的虚拟复原及性别和种族的识别;⑤全息展演技术面临高计算性能需求、艺术与技术融合的精准度、硬件兼容性、实时性、沉浸感和互动性等挑战。针对这5个方面的需求和挑战,首先,对近些年的相关领域的研究进行综述;然后,总结西北大学文化遗产数字化国家地方联合工程研究中心的系列成果;最后,对文化遗产数字化领域的未来研究方向进行展望。 展开更多
关键词 文化遗产数字化 智慧博物馆 文物虚拟复原 知识图谱 全息展演技术
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提高WC-Co硬质合金高温性能的研究进展
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作者 胡泽艺 肖银春 +2 位作者 范才河 林孝良 卢益玲 《包装学报》 2025年第5期11-23,共13页
WC-Co硬质合金凭借其卓越的硬度、耐磨性和高温力学性能,被广泛应用于航空航天、矿山开采及装备制造等对材料要求极为苛刻的领域。然而,随着高端制造业的不断进步,对材料性能的要求日益提高,WC-Co硬质合金在高温环境下的服役稳定性、抗... WC-Co硬质合金凭借其卓越的硬度、耐磨性和高温力学性能,被广泛应用于航空航天、矿山开采及装备制造等对材料要求极为苛刻的领域。然而,随着高端制造业的不断进步,对材料性能的要求日益提高,WC-Co硬质合金在高温环境下的服役稳定性、抗氧化性及高温力学性能面临严峻挑战。本文系统综述了影响WC-Co硬质合金高温性能的诸多因素,涵盖合金成分、高温氧化行为及力学性能退化机制等方面,详细分析了这些因素对材料组织稳定性和性能的具体影响规律。同时,重点探讨了提升硬质合金高温性能的主要研究方法与最新进展,包括热处理与烧结工艺的优化、晶粒细化技术的应用、黏结相的优化替代,以及添加稀有金属碳化物等策略。此外,还简要介绍了分子动力学模拟技术在WC-Co硬质合金研究中的实际应用。 展开更多
关键词 WC-CO硬质合金 氧化行为 高温性能 分子动力学
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气象因子对绿茶游离氨基酸和咖啡碱含量的影响
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作者 孙奇芳 张璐寒 +4 位作者 余文杰 董方 李艳 范晓青 罗丽萍 《应用气象学报》 北大核心 2025年第3期307-315,共9页
收集整理2018—2023年我国10个省份绿茶的144条游离氨基酸含量和12个省市220条咖啡碱含量数据,应用Meta和相关分析揭示茶叶品质成分含量及影响的关键气象因子。结果表明:游离氨基酸含量空间分布自西南向东北逐渐增加,云南、贵州和四川... 收集整理2018—2023年我国10个省份绿茶的144条游离氨基酸含量和12个省市220条咖啡碱含量数据,应用Meta和相关分析揭示茶叶品质成分含量及影响的关键气象因子。结果表明:游离氨基酸含量空间分布自西南向东北逐渐增加,云南、贵州和四川游离氨基酸含量较低,浙江和安徽游离氨基酸含量最高。随茶叶采摘前30 d的有限日照日数(日照时数大于等于0.1 h但小于等于6 h的日数)增加,游离氨基酸含量逐渐减少(每增加1 d,游离氨基酸含量平均减少4.68%,最大可减少30.39%)。咖啡碱含量空间分布自东南至西北逐渐增加,河南、湖北和四川东北部咖啡碱含量较高,浙江、福建和广东东北部咖啡碱含量较低,随采摘前30 d大雨及以下日数(降水量大于等于1 mm但小于等于25 mm的日数)增加而减少(每增加1 d,咖啡碱含量含量平均减少4.43%,最大可减少25.58%)。有限日照日数、大雨及以下日数可能是影响游离氨基酸含量和咖啡碱含量的关键气象因子。 展开更多
关键词 绿茶 游离氨基酸 咖啡碱 气象因子
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动量-自适应人工神经网络下的舰船目标检测
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作者 贾世杰 陈伟 《舰船科学技术》 北大核心 2025年第11期175-179,共5页
舰船种类丰富、大小差异显著,从小型快艇到大型航空母舰,尺度范围跨度大,给舰船目标类型识别检测带来较大难度。为解决这一问题,提出了基于动量-自适应人工神经网络的舰船目标检测方法。此方法利用最大类间方差算法,结合图像灰度特性,... 舰船种类丰富、大小差异显著,从小型快艇到大型航空母舰,尺度范围跨度大,给舰船目标类型识别检测带来较大难度。为解决这一问题,提出了基于动量-自适应人工神经网络的舰船目标检测方法。此方法利用最大类间方差算法,结合图像灰度特性,通过计算类间方差最大化,将图像划分为目标与背景;采用最小外接矩形法提取舰船目标特征,通过计算能够完全包围舰船的最小矩形,获取目标的几何特征信息;将所提取特征输入基于改进人工神经网络的舰船目标检测模型,模型在权重调节中引入动量项,设计自适应学习率,增强网络对舰船特征的学习与识别能力,实现对舰船目标的识别检测。实验结果验证,该方法能够清晰地将舰船目标从背景中分离出来;对于单个舰船目标类型以及多目标类型的识别检测结果均稳定、准确。 展开更多
关键词 人工神经网络 舰船目标 识别检测 最大类间方差算法 最小外接矩形法
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国际视野下的农业绿色发展:政策前沿、技术创新与未来取向
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作者 王越 亢志华 《中国农学通报》 2025年第26期148-156,共9页
农业绿色发展作为世界农业发展的主流也将是中国建设农业强国的必由之路。本研究选取美国、欧盟和日本等主要发达经济体,回顾其农业绿色发展进程,瞄准政策改革前沿及科技创新导向,总结其发展特点及经验。研究发现,美国农业绿色转型主要... 农业绿色发展作为世界农业发展的主流也将是中国建设农业强国的必由之路。本研究选取美国、欧盟和日本等主要发达经济体,回顾其农业绿色发展进程,瞄准政策改革前沿及科技创新导向,总结其发展特点及经验。研究发现,美国农业绿色转型主要面临应对气候变化风险和减碳固碳压力,其政策改革兼顾环境保护与农业生产,以提高农业气候变化适应性为目标;欧盟主要面临生物多样性锐减问题,新一轮政策改革以单一生态修复为导向、以牺牲农作物产量为代价;日本则因全球气候变化影响,其政策强调稳定极端天气下高质量农产品的供给。不同发展政策导向下,三大经济体分别演化出了以生物技术为导向的美国农业绿色科技创新模式、基于自然解决方案的欧洲农业绿色科技创新模式、以信息技术与脱碳为导向的日本农业绿色科技创新模式。“十四五”时期中国农业绿色发展虽然已经取得了实质性进展,但与上述发达经济体相比在科技投入强度、科技研发前沿、政策激励效果方面仍存在差距,未来应注重细化绿色发展考核、完善绿色补贴机制、促进产业链主体协同、强化科技成果转化。 展开更多
关键词 农业绿色发展 政策前沿 技术创新 国际比较
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Comparative analysis of empirical and deep learning models for ionospheric sporadic E layer prediction
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作者 BingKun Yu PengHao Tian +6 位作者 XiangHui Xue Christopher JScott HaiLun Ye JianFei Wu Wen Yi TingDi Chen XianKang Dou 《Earth and Planetary Physics》 EI CAS 2025年第1期10-19,共10页
Sporadic E(Es)layers in the ionosphere are characterized by intense plasma irregularities in the E region at altitudes of 90-130 km.Because they can significantly influence radio communications and navigation systems,... Sporadic E(Es)layers in the ionosphere are characterized by intense plasma irregularities in the E region at altitudes of 90-130 km.Because they can significantly influence radio communications and navigation systems,accurate forecasting of Es layers is crucial for ensuring the precision and dependability of navigation satellite systems.In this study,we present Es predictions made by an empirical model and by a deep learning model,and analyze their differences comprehensively by comparing the model predictions to satellite RO measurements and ground-based ionosonde observations.The deep learning model exhibited significantly better performance,as indicated by its high coefficient of correlation(r=0.87)with RO observations and predictions,than did the empirical model(r=0.53).This study highlights the importance of integrating artificial intelligence technology into ionosphere modelling generally,and into predicting Es layer occurrences and characteristics,in particular. 展开更多
关键词 ionospheric sporadic E layer radio occultation ionosondes numerical model deep learning model artificial intelligence
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Accuracy of machine electrocardiogram interpretation and implementation of a de-prioritization protocol in the emergency department
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作者 Adam K Stanley Isobel Sonksen +2 位作者 Henry Morgan Nicola Hilton Sukhbir Bhullar 《World Journal of Emergency Medicine》 2025年第5期486-487,共2页
Computer analysis of electrocardiograms(ECGs)was introduced more than 50 years ago,with the aim to improve efficiency and clinical workflow.[1,2]However,inaccuracies have been documented in the literature.[3,4]Researc... Computer analysis of electrocardiograms(ECGs)was introduced more than 50 years ago,with the aim to improve efficiency and clinical workflow.[1,2]However,inaccuracies have been documented in the literature.[3,4]Research indicates that emergency department(ED)clinician interruptions occur every 4-10 min,which is significantly more common than in other specialties.[5]This increases the cognitive load and error rates and impacts patient care and clinical effi ciency.[1,2,5]De-prioritization protocols have been introduced in certain centers in the United Kingdom(UK),removing the need for clinician ECG interpretation where ECGs have been interpreted as normal by the machine. 展开更多
关键词 cognitive load de prioritization protocol improve efficiency clinical workflow howeverinaccuracies computer analysis electrocardiograms ecgs computer analysis electrocardiograms machine electrocardiogram interpretation emergency department error rates
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Locally Enhanced Flow and Electric Fields Through a Tip Effect for Efficient Flow‑Electrode Capacitive Deionization
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作者 Ziquan Wang Xiangfeng Chen +5 位作者 Yuan Zhang Jie Ma Zhiqun Lin Amor Abdelkader Maria‑Magdalena Titirici Libo Deng 《Nano-Micro Letters》 SCIE EI CAS 2025年第2期1-17,共17页
Low-electrode capacitive deionization(FCDI)is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters.However,it still suffers from inefficient charge transfer... Low-electrode capacitive deionization(FCDI)is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters.However,it still suffers from inefficient charge transfer and ion transport kinetics due to weak turbulence and low electric intensity in flow electrodes,both restricted by the current collectors.Herein,a new tip-array current collector(designated as T-CC)was developed to replace the conventional planar current collectors,which intensifies both the charge transfer and ion transport significantly.The effects of tip arrays on flow and electric fields were studied by both computational simulations and electrochemical impedance spectroscopy,which revealed the reduction of ion transport barrier,charge transport barrier and internal resistance.With the voltage increased from 1.0 to 1.5 and 2.0 V,the T-CC-based FCDI system(T-FCDI)exhibited average salt removal rates(ASRR)of 0.18,0.50,and 0.89μmol cm^(-2) min^(-1),respectively,which are 1.82,2.65,and 2.48 folds higher than that of the conventional serpentine current collectors,and 1.48,1.67,and 1.49 folds higher than that of the planar current collectors.Meanwhile,with the solid content in flow electrodes increased from 1 to 5 wt%,the ASRR for T-FCDI increased from 0.29 to 0.50μmol cm^(-2) min^(-1),which are 1.70 and 1.67 folds higher than that of the planar current collectors.Additionally,a salt removal efficiency of 99.89%was achieved with T-FCDI and the charge efficiency remained above 95%after 24 h of operation,thus showing its superior long-term stability. 展开更多
关键词 Flow-electrode Capacitive deionization Current collector Tip effect DESALINATION
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Reduction of losses in electric power distribution system-dynamic reconfiguration case study
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作者 Branimir Novoselnik Drago Bago +1 位作者 Jadranko Matuško Mato Baotić 《Control Theory and Technology》 2025年第1期49-63,共15页
This paper deals with reduction of losses in electric power distribution system through a dynamic reconfiguration case study of a grid in the city of Mostar,Bosnia and Herzegovina.The proposed solution is based on a n... This paper deals with reduction of losses in electric power distribution system through a dynamic reconfiguration case study of a grid in the city of Mostar,Bosnia and Herzegovina.The proposed solution is based on a nonlinear model predictive control algorithm which determines the optimal switching operations of the distribution system.The goal of the control algorithm is to find the optimal radial network topology which minimizes cumulative active power losses and maximizes voltages across the network while simultaneously satisfying all system constraints.The optimization results are validated through multiple simulations(using real power demand data collected for a few characteristic days during winter and summer)which demonstrate the efficiency and usefulness of the developed control algorithm in reducing the grid losses by up to 14%. 展开更多
关键词 Nonlinear model predictive control Dynamic reconfiguration Power distribution system Mixed-integer programming Real-life case study
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Framework for adaptive multimodal serious games for early intervention of autistic children
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作者 Zhiqi XU Yuyong ZHAO +2 位作者 Jie WANG Jian CHANG Yuetian ZHANG 《虚拟现实与智能硬件(中英文)》 2025年第5期523-542,共20页
Background Autism spectrum disorder(ASD)is a pervasive developmental disorder characterized by difficulties in social communication and restricted,repetitive behaviors.Early intervention is essential to improve develo... Background Autism spectrum disorder(ASD)is a pervasive developmental disorder characterized by difficulties in social communication and restricted,repetitive behaviors.Early intervention is essential to improve developmental outcomes in children with ASD.Serious games,which combine educational objectives with game based interactions,have shown potential as tools for early intervention in patients with ASD.However,in China,the development of serious games specifically designed for children with ASD remains in its infancy,with significant gaps in technical frameworks and effective data management methods.Method This paper proposes a framework aimed at facilitating the development of multimodal serious games designed for ASD interventions.We demonstrated the feasibility of the framework by developing and integrating several components,such as web applications,mobile games,and augmented reality games.These tools are interconnected to achieve data connectivity and management.Additionally,adaptive mechanics were employed within the framework to analyze real-time player data,which allowed the game difficulty to be dynamically adjusted and provide a personalized experience for each child.Results The framework successfully integrated various multimodal games,ensuring that real-time data management supported personalized game experiences.This approach ensured that the interventions remained appropriately challenging while still achievable.Conclusion The results indicate that the proposed framework enhances collaboration among therapists,parents,and developers while also improving the effectiveness of ASD interventions.By delivering personalized gameplay experiences that are both challenging and achievable,the framework offers a scalable platform for the future development of serious games. 展开更多
关键词 Autism spectrum disorder(ASD) Serious games Multimodal games Early intervention Technical framework Augmented reality(AR)Games Mobile games
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基于Internet的远程音乐教育模式的探讨 被引量:1
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作者 唐小波 《星海音乐学院学报》 2002年第1期68-70,共3页
本文简要地介绍了远程音乐教育的优越性和基本特点,并就其结构模式及其 功能、教学方式和远程音乐考试系统作了较具体的阐述。
关键词 Internet 远程教育 课件 BBS E-MAIL 题库系统
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Renewable energy and its impact on agricultural and economic development in the Netherlands and South Africa
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作者 Saul NGARAVA Alois Aldridge MUGADZA 《Regional Sustainability》 2025年第2期1-16,共16页
The use ofrenewable energyisan important way toachieve sustainable agriculturalandeconomic development.However,there are differences in accessto renewable energy between the Global North and Global South.This study ut... The use ofrenewable energyisan important way toachieve sustainable agriculturalandeconomic development.However,there are differences in accessto renewable energy between the Global North and Global South.This study utilisedan autoregressive distributed lag-error correctionmodel and thedata spanning from 1991to 2021 to comparatively analyse the dynamic relationship amongrenewable energy consumption,the value of agricultural production,gross domestic product(GDP),economic diversificationindex,urban population,the total water extraction for agricultural withdrawal,and trade balancein the Netherlands and South Africa.In the shortrun,renewable energy consumption was increased by the value of agricultural productionbut decreased by GDPin South Africa.In the longrun,renewable energy consumption and GDP increased the value of agricultural production,while the value of agricultural production also increased GDP in South Africa.However,in the Netherlands,there was no short-and long-run relationship betweenrenewable energy consumption and agricultural and economic development.The results revealedthat there was a short-and long-run relationship in South Africa.Moreover,in the Netherlands,the adjustment speed was-1.46 forrenewable energy consumption with an error correction of 0.68 a(8.22 months).In South Africa,the adjustment speedwas-1.28 forrenewable energy consumption with an error correction of 0.78 a(9.38 months).Therefore,compared to South Africa,renewable energy consumptionin the Netherlands takes less time to return to balance after a shock.Thesefindings signify different trajectories on sectoral and economic transition initiatives spurred usingrenewable energy between the Netherlands and South Africa.Policy relating to initiatives such as“agro-energy communities”in Global South countries such as South Africa should be emphasised to promote the use of renewable energy in the agricultural sector. 展开更多
关键词 Autoregressive distributed lag-error correction model(ARDL-ECM) Renewable energy consumption Agricultural production Economic development The Netherlands South Africa
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Advancements in the diagnosis of biliopancreatic diseases:A comparative review and study on future insights
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作者 Eyad Gadour Bogdan Miutescu +2 位作者 Zeinab Hassan Emad S Aljahdli Khurram Raees 《World Journal of Gastrointestinal Endoscopy》 2025年第4期6-23,共18页
Owing to the complex and often asymptomatic presentations,the diagnosis of biliopancreatic diseases,including pancreatic and biliary malignancies,remains challenging.Recent technological advancements have remarkably i... Owing to the complex and often asymptomatic presentations,the diagnosis of biliopancreatic diseases,including pancreatic and biliary malignancies,remains challenging.Recent technological advancements have remarkably improved the diagnostic accuracy and patient outcomes in these diseases.This review explores key advancements in diagnostic modalities,including biomarkers,imaging techniques,and artificial intelligence(AI)-based technologies.Biomarkers,such as cancer antigen 19-9,KRAS mutations,and inflammatory markers,provide crucial insights into disease progression and treatment responses.Advanced imaging modalities include enhanced computed tomography(CT),positron emission tomography-CT,magnetic resonance cholangiopancreatography,and endoscopic ultrasound.AI integration in imaging and pathology has enhanced diagnostic precision through deep learning algorithms that analyze medical images,automate routine diagnostic tasks,and provide predictive analytics for personalized treatment strategies.The applications of these technologies are diverse,ranging from early cancer detection to therapeutic guidance and real-time imaging.Biomarker-based liquid biopsies and AI-assisted imaging tools are essential for non-invasive diagnostics and individualized patient management.Furthermore,AI-driven models are transforming disease stratification,thus enhancing risk assessment and decision-making.Future studies should explore standardizing biomarker validation,improving AI-driven diagnostics,and expanding the accessibility of advanced imaging technologies in resource-limited settings.The continued development of non-invasive diagnostic techniques and precision medicine approaches is crucial for optimizing the detection and management of biliopancreatic diseases.Collaborative efforts between clinicians,researchers,and industry stakeholders will be pivotal in applying these advancements in clinical practice. 展开更多
关键词 Biliopancreatic diseases Endoscopic ultrasound Endoscopic retrograde cholangiopancreatography Magnetic resonance cholangiopancreatography Peroral cholangiopancreatoscopy Diagnostic advancements Biomarkers in biliopancreatic diseases Artificial intelligence in gastroenterology
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Sunlight promotes aboveground carbon loss by producing polysaccharides from litter decomposition in a temperate forest
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作者 Lu Chang Jiaojiao Deng +7 位作者 Juanjuan Zhang Qinglong Fu Tao Wang Takashi Osono Huan Peng Thomas Matthew Robson Hiroko Kurokawa Qing-Wei Wang 《Journal of Forestry Research》 2025年第2期187-197,共11页
Photodegradation is considered as a universal contributing factor to litter decomposition and carbon(C)cycling within the Earth’s biomes.Identifying how solar radiation modifies the molecular structure of litter is e... Photodegradation is considered as a universal contributing factor to litter decomposition and carbon(C)cycling within the Earth’s biomes.Identifying how solar radiation modifies the molecular structure of litter is essen-tial to understand the mechanism controlling its decom-position and reaction to shifts in climatic conditions and land-use.In this study,we performed a spectral-attenuation experiment following litter decomposition in an understory and gap of a temperate deciduous forest.We found that short-wavelength visible light,especially blue light,was the main factor driving variation in litter molecular struc-ture of Fagus crenata Blume,Quercus crispula Blume,Acer carpinifolium Siebold&Zuccarini and Betula platyphylla Sukaczev,explaining respectively 56.5%,19.4%,66.3%,and 16.7%of variation in its chemical composition.However,the variation also depended on canopy openness:Only in the forest gap was lignin aromatic C negatively associated with C-oxygen(C–O)bonding in polysaccharides receiv-ing treatments containing blue light of the full spectrum of solar radiation.Regardless of species,the decomposition index of litter that explained changes in mass and lignin loss was driven by the relative content of C–O stretching in poly-saccharides and lignin aromatic C.The results suggest that the availability of readily degradable polysaccharides pro-duced by the reduction in lignin aromatic C most plausibly explains the rate of litter photodegradation.Photo-products of photodegradation might augment the C pool destabilized by the input of readily degradable organic compounds(i.e.,polysaccharides). 展开更多
关键词 Forest carbon cycling Solar radiation PHOTODEGRADATION Litter molecular structure Fourier transform infrared(FTIR)spectroscopy
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人工智能算法在铁道车辆动力学仿真中的应用进展 被引量:11
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作者 唐兆 董少迪 +3 位作者 罗仁 蒋涛 邓锐 张建军 《交通运输工程学报》 EI CSCD 北大核心 2021年第1期250-266,共17页
梳理了人工智能算法在铁道车辆系统动力学仿真中的应用实例和国内外相关文献,概述了铁道车辆动力学仿真中常用的机器学习和深度学习算法,归纳和评述了2种学习算法在铁道车辆系统动力学建模与仿真中的应用分类;从铁道车辆系统动力学建模... 梳理了人工智能算法在铁道车辆系统动力学仿真中的应用实例和国内外相关文献,概述了铁道车辆动力学仿真中常用的机器学习和深度学习算法,归纳和评述了2种学习算法在铁道车辆系统动力学建模与仿真中的应用分类;从铁道车辆系统动力学建模、动力学性能预测与动力学性能优化等方面入手,详细讨论了人工智能算法应用在力元建模和仿真、轨道不平顺预测、运行平稳性预测、噪声预测、侧风安全性预测、运行安全性预测、悬挂优化、轮轨匹配优化、结构优化以及主动与半主动控制等领域的优势和局限性,指出了现阶段人工智能算法在动力学仿真应用中主要面临的训练样本缺乏、泛化能力不够、可解释性欠缺等问题;展望了今后人工智能算法和车辆系统动力学交叉研究的发展方向和重点研究内容。研究结果表明:融合经典力学和人工智能算法结合的混合建模理论可作为之后的重点研究方向;人工智能算法对解决随机动力学中的随机不确定性,提高随机动力学的性能具有较大的应用潜力;通过人工智能算法与优化算法相结合来实现动力学性能优化,可充分发挥人工智能算法的优势。 展开更多
关键词 铁道车辆 人工智能算法 动力学建模与仿真 性能预测 性能优化 机器学习 深度学习
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自然旅游地社区居民旅游发展期望与旅游影响感知对其旅游态度的影响--对中国九寨沟和英国NF国家公园的比较研究 被引量:61
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作者 程绍文 张捷 +1 位作者 徐菲菲 梁玥琳 《地理研究》 CSCD 北大核心 2010年第12期2179-2188,共10页
现有研究表明,旅游目的地社区居民的旅游影响感知会影响他们对旅游的态度;但鲜有研究去分析旅游地社区居民的旅游发展期望对居民旅游态度的影响。本文以中国九寨沟和英国New Forest国家公园为例,运用SPSS统计分析技术,分析了两地居民旅... 现有研究表明,旅游目的地社区居民的旅游影响感知会影响他们对旅游的态度;但鲜有研究去分析旅游地社区居民的旅游发展期望对居民旅游态度的影响。本文以中国九寨沟和英国New Forest国家公园为例,运用SPSS统计分析技术,分析了两地居民旅游发展期望与旅游影响感知特点及其对居民旅游态度的影响路径及可能原因。研究结论表明:(1)居民的旅游获益感知直接影响居民的旅游支持度;(2)目的地居民的旅游发展期望直接影响着居民的旅游影响感知,尤其是旅游获益感知;并通过旅游影响感知的中介作用,间接影响居民的旅游态度;(3)自然旅游地居民的旅游发展期望都很积极正面,并存在明显的文化差异;尽管两地居民的旅游获益感知均显著逊于其旅游发展期望,但两地居民并没有因为期望落差而对当地旅游开发持否定态度。 展开更多
关键词 旅游发展期望 旅游影响感知 旅游态度 九寨沟 英国New Forest国家公园
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点到隐式曲面的正交投影计算 被引量:5
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作者 徐海银 方雄兵 胡利安 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2008年第12期1641-1646,1652,共7页
针对点到隐式曲面的正交投影问题,提出一种稳定的几何迭代算法.首先构造初始点处的一条特殊的法截线,并给出沿着该法截线追踪投影点的二阶泰勒迭代方法;然后将给定点向初始点处的法截线的曲率圆作投影,提出基于曲率的步长控制策略,在此... 针对点到隐式曲面的正交投影问题,提出一种稳定的几何迭代算法.首先构造初始点处的一条特殊的法截线,并给出沿着该法截线追踪投影点的二阶泰勒迭代方法;然后将给定点向初始点处的法截线的曲率圆作投影,提出基于曲率的步长控制策略,在此基础上给出了基于梯度的迭代误差矫正方法.仿真结果表明,该算法具有良好的收敛性、鲁棒性以及精确性. 展开更多
关键词 正交投影 隐式曲面 法截面 法截线 曲率圆 步长
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从“变色龙效应”到“镜像神经元”再到“模仿过多症”--作为社会交流产物的人类无意识模仿 被引量:10
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作者 汪寅 臧寅垠 陈巍 《心理科学进展》 CSSCI CSCD 北大核心 2011年第6期916-924,共9页
人类无意识模仿是指人们在社会交流时会相互无意识地模仿对方的一些动作、表情和行为方式。其在个体社会认知以及人际交流上扮演着重要的角色。通过回顾近十年来人类无意识模仿的各个领域内的研究进展,以及分析无意识模仿的行为学效应,... 人类无意识模仿是指人们在社会交流时会相互无意识地模仿对方的一些动作、表情和行为方式。其在个体社会认知以及人际交流上扮演着重要的角色。通过回顾近十年来人类无意识模仿的各个领域内的研究进展,以及分析无意识模仿的行为学效应,脑神经机制以及病理学调控,可以得出如下结论:所有神经层面以及行为层面的人类无意识模仿现象都是社会交流的产物。该观点在澄清无意识模仿神经机制以及促进幼儿社会认知发展方面具有一定启示意义,而探索孤独症患者无意识模仿障碍的病理机制有望为该领域的未来研究开启新的方向。 展开更多
关键词 人类无意识模仿 变色龙效应 镜像神经元 联想学习学说 模仿过多症 社会交流 孤独症
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