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Coincidence Point and Common Fixed Point Theorems on b-Metric-like Spaces
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作者 LUO Ting 《应用数学》 北大核心 2025年第3期831-840,共10页
In this paper,we establish common fixed point theorems for expansive map?pings on b-metric-like space and coincidence point for f-weakly isotone increasing mappings in partially ordered b-metric-like space.The main re... In this paper,we establish common fixed point theorems for expansive map?pings on b-metric-like space and coincidence point for f-weakly isotone increasing mappings in partially ordered b-metric-like space.The main results generalize and extend several well-known comparable results from the existing literature.Moreover,some examples are provided to illustrate the main results. 展开更多
关键词 b-metric-like space Partially ordered b-metric-like space Expansive mapping f-weakly isotone mapping Coincidence point Common fixed point
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Products of multiplication,composition and differentiation on weighted Bergman spaces in the unit ball
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作者 ZHANG Chao QIN Yuehai 《中山大学学报(自然科学版)(中英文)》 北大核心 2025年第2期160-169,共10页
The boundness and compactness of products of multiplication,composition and differentiation on weighted Bergman spaces in the unit ball are studied.We define the differentiation operator on the space of holomorphic fu... The boundness and compactness of products of multiplication,composition and differentiation on weighted Bergman spaces in the unit ball are studied.We define the differentiation operator on the space of holomorphic functions in the unit ball by radial derivative.Then we extend the Sharma's results. 展开更多
关键词 composition operator multiplication operator differentiation operator weighted Bergman space
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The Paley-Wiener Theorem for General Weighted Hardy Spaces on Tube Domains
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作者 HUANG Yun ZHANG Dawei 《应用数学》 北大核心 2025年第3期841-849,共9页
In this paper,the Paley-Wiener theorem is extended to the analytic function spaces with general weights.We first generalize the theorem to weighted Hardy spaces Hp(0<p<∞)on tube domains by constructing a sequen... In this paper,the Paley-Wiener theorem is extended to the analytic function spaces with general weights.We first generalize the theorem to weighted Hardy spaces Hp(0<p<∞)on tube domains by constructing a sequence of L^(1)functions converging to the given function and verifying their representation in the form of Fourier transform to establish the desired result of the given function.Applying this main result,we further generalize the Paley-Wiener theorem for band-limited functions to the analytic function spaces L^(p)(0<p<∞)with general weights. 展开更多
关键词 Paley-Wiener Theorem Fourier transform Weighted Hardy space Tube domain
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Three-dimensional finite-time optimal cooperative guidance with integrated information fusion observer
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作者 Yiao Zhan Linwei Wang Di Zhou 《Defence Technology(防务技术)》 2025年第4期12-28,共17页
Intercepting high-maneuverability hypersonic targets in near-space environments poses significant challenges due to their extreme speeds and evasive capabilities.To address these challenges,this study presents an inte... Intercepting high-maneuverability hypersonic targets in near-space environments poses significant challenges due to their extreme speeds and evasive capabilities.To address these challenges,this study presents an integrated approach that combines a Three-Dimensional Finite-Time Optimal Cooperative Guidance Law(FTOC)with an Information Fusion Anti-saturation Predefined-time Observer(IFAPO).The proposed FTOC guidance law employs a nonlinear,non-quadratic finite-time optimal control strategy designed for rapid convergence within the limited timeframes of near-space interceptions,avoiding the need for remaining flight time estimation or linear decoupling inherent in traditional methods.To complement the guidance strategy,the IFAPO leverages multi-source information fusion theory and incorporates anti-saturation mechanisms to enhance target maneuver estimation.This method ensures accurate and real-time prediction of target acceleration while maintaining predefined convergence performance,even under complex interception conditions.By integrating the FTOC guidance law and IFAPO,the approach optimizes cooperative missile positioning,improves interception success rates,and minimizes fuel consumption,addressing practical constraints in military applications.Simulation results and comparative analyses confirm the effectiveness of the integrated approach,demonstrating its capability to achieve cooperative interception of highly maneuvering targets with enhanced efficiency and reduced economic costs,aligning with realistic combat scenarios. 展开更多
关键词 Anti-saturation predefined-time observer Nonlinear finite-time optimal control three-dimensional guidance Information fusion
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Research on three-dimensional attack area based on improved backtracking and ALPS-GP algorithms of air-to-air missile
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作者 ZHANG Haodi WANG Yuhui HE Jiale 《Journal of Systems Engineering and Electronics》 2025年第1期292-310,共19页
In the field of calculating the attack area of air-to-air missiles in modern air combat scenarios,the limitations of existing research,including real-time calculation,accuracy efficiency trade-off,and the absence of t... In the field of calculating the attack area of air-to-air missiles in modern air combat scenarios,the limitations of existing research,including real-time calculation,accuracy efficiency trade-off,and the absence of the three-dimensional attack area model,restrict their practical applications.To address these issues,an improved backtracking algorithm is proposed to improve calculation efficiency.A significant reduction in solution time and maintenance of accuracy in the three-dimensional attack area are achieved by using the proposed algorithm.Furthermore,the age-layered population structure genetic programming(ALPS-GP)algorithm is introduced to determine an analytical polynomial model of the three-dimensional attack area,considering real-time requirements.The accuracy of the polynomial model is enhanced through the coefficient correction using an improved gradient descent algorithm.The study reveals a remarkable combination of high accuracy and efficient real-time computation,with a mean error of 91.89 m using the analytical polynomial model of the three-dimensional attack area solved in just 10^(-4)s,thus meeting the requirements of real-time combat scenarios. 展开更多
关键词 air combat three-dimensional attack area improved backtracking algorithm age-layered population structure genetic programming(ALPS-GP) gradient descent algorithm
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The use of carbon-based particle electrodes in three-dimensional electrode reactors for wastewater treatment 被引量:1
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作者 LU Hua-yu LIU Wei-feng +1 位作者 QIN Lei LIU Xu-guang 《新型炭材料(中英文)》 SCIE EI CAS CSCD 北大核心 2024年第5期973-991,共19页
The use of three-dimensional(3D)electrodes in water treatment is competitive because of their high catalytic efficiency,low energy consumption and promising development.The use of particle electrodes is a key research... The use of three-dimensional(3D)electrodes in water treatment is competitive because of their high catalytic efficiency,low energy consumption and promising development.The use of particle electrodes is a key research focus in this technology.They are usually in the form of particles that fill the space between the cathode and anode,and the selection of materials used is important.Carbon-based materials are widely used because of their large specific surface area,good adsorption performance,high chemical stability and low cost.The principles of 3D electrode technology are introduced and recent research on its use for degrading organic pollutants using carbon-based particle electrodes is summarized.The classification of particle electrodes is introduced and the challenges for the future development of carbon-based particle electrodes in wastewater treatment are discussed. 展开更多
关键词 Environmental pollution three-dimensional electrode technology Carbon-based materials Carbon-based particle electrode
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Risk Assessment of Coal Mine Water Hazard Based on Three-Dimensional Model of Geology and Underground Space 被引量:1
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作者 Kai Zhang~1,Ming Huang~1,Bin Tang~2,Fan Cui~1 1.Laboratory of Coal Resources and Mine Safety,China University of Mining and Technology,Beijing 100083,China. 2.China Water Investment Co.Ltd,Beijing 100053,China 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期279-279,共1页
Mine safety have top-five disasters,which including the water,gas,fire,dust and geological dynamic disaster.The coal mine water disaster is one of the important factors which restricted the development of China’s coa... Mine safety have top-five disasters,which including the water,gas,fire,dust and geological dynamic disaster.The coal mine water disaster is one of the important factors which restricted the development of China’s coal production.It is showed by statistics that 60%of mine accidents are affected by groundwater,which not only result in the production losses,casualties and a variety of 展开更多
关键词 DISASTER risk assessment three-dimensional model of GEOLOGY and UNDERGROUND space emergency RESCUE
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数据空间建设的实践进展与运营模式分析——基于Data Spaces Radar的案例 被引量:4
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作者 夏义堃 程铄 +1 位作者 王雪 钱锦琳 《图书与情报》 CSSCI 北大核心 2024年第2期18-32,共15页
数据空间建设为数据要素的价值实现提供了可资借鉴的实践经验,全面解析其实践进展与运营模式,有助于破解数据流通的现实堵点、拓展数据利用的发展思路。文章首先将结构主义分析方法中的案例研究法作为主要研究方法,综合运用文献调研、... 数据空间建设为数据要素的价值实现提供了可资借鉴的实践经验,全面解析其实践进展与运营模式,有助于破解数据流通的现实堵点、拓展数据利用的发展思路。文章首先将结构主义分析方法中的案例研究法作为主要研究方法,综合运用文献调研、比较分析等方法,以Data Spaces Radar为案例来源,从实践进展、运营模式、核心要素等维度提炼数据空间建设特征。其次,在制度与技术的双轮驱动下,数据空间建设秉持制度规范统一性、技术设计整体性和治理模式协同性的架构原则,并按照产业思维、底线思维、信任思维、链式思维、集约思维的底层逻辑,形成较为完整的运营体系。未来应着力探索和解决数据空间视域下的数据资源价值化开发路径,针对数据流通堵点、利用痛点及信任难点问题,从体制机制、政策框架与技术应用等角度为推进我国的数据要素流通利用提供有益参考。 展开更多
关键词 数据空间 数据流通利用 数据自主权 运营模式 数据信任
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Influence of sampling on three-dimensional surface shape measurement
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作者 QIAO Nao-sheng Shang Xue 《中国光学(中英文)》 EI CAS CSCD 北大核心 2024年第6期1512-1520,共9页
In order to accurately measure an object’s three-dimensional surface shape,the influence of sampling on it was studied.First,on the basis of deriving spectra expressions through the Fourier transform,the generation o... In order to accurately measure an object’s three-dimensional surface shape,the influence of sampling on it was studied.First,on the basis of deriving spectra expressions through the Fourier transform,the generation of CCD pixels was analyzed,and its expression was given.Then,based on the discrete expression of deformation fringes obtained after sampling,its Fourier spectrum expression was derived,resulting in an infinitely repeated"spectra island"in the frequency domain.Finally,on the basis of using a low-pass filter to remove high-order harmonic components and retaining only one fundamental frequency component,the inverse Fourier transform was used to reconstruct the signal strength.A method of reducing the sampling interval,i.e.,reducing the number of sampling points per fringe,was proposed to increase the ratio between the sampling frequency and the fundamental frequency of the grating.This was done to reconstruct the object’s surface shape more accurately under the condition of m>4.The basic principle was verified through simulation and experiment.In the simulation,the sampling intervals were 8 pixels,4 pixels,2 pixels,and 1 pixel,the maximum absolute error values obtained in the last three situations were 88.80%,38.38%,and 31.50%in the first situation,respectively,and the corresponding average absolute error values are 71.84%,43.27%,and 32.26%.It is demonstrated that the smaller the sampling interval,the better the recovery effect.Taking the same four sampling intervals in the experiment as in the simulation can also lead to the same conclusions.The simulated and experimental results show that reducing the sampling interval can improve the accuracy of object surface shape measurement and achieve better reconstruction results. 展开更多
关键词 three-dimensional surface shape measurement sampling interval spectra overlapping measurement accuracy
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Three-Dimensional Space Interpolation of Grey / Depth Image Sequence-A New Technique of Computer Graphics Synthesis
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作者 Wang Xincheng, Zhu Weile, Zhu Xiaokun and Gu DerenChengdu University of Electronic Science and Technology, Chengdu 610054 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1993年第3期70-77,共8页
This paper advances a three-dimensional space interpolation method of grey / depth image sequence, which breaks free from the limit of original practical photographing route. Pictures can cruise at will in space. By u... This paper advances a three-dimensional space interpolation method of grey / depth image sequence, which breaks free from the limit of original practical photographing route. Pictures can cruise at will in space. By using space sparse sampling, great memorial capacity can be saved and reproduced scenes can be controlled. To solve time consuming and complex computations in three-dimensional interpolation algorithm, we have studied a fast and practical algorithm of scattered space lattice and that of 'Warp' algorithm with proper depth. By several simple aspects of three dimensional space interpolation, we succeed in developing some simple and practical algorithms. Some results of simulated experiments with computers have shown that the new method is absolutely feasible. 展开更多
关键词 Grey / depth image three-dimensional space interpolation Computer graphics synthesis Algorithms.
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2001—2023年中国城市地下空间开发利用研究特征与趋势——基于CiteSpace和VOSviewer知识图谱分析 被引量:4
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作者 吴健波 岳伟涛 王恩元 《中国安全生产科学技术》 北大核心 2025年第2期83-89,共7页
为探究国内城市地下空间开发利用研究特征与趋势,选取2001—2023年中国知网(CNKI)数据库收录的1146篇城市地下空间开发利用领域文献,基于CiteSpace和VOSviewer文献计量软件从发文量趋势演化、作者和机构合作构成网络、关键词共现及聚类... 为探究国内城市地下空间开发利用研究特征与趋势,选取2001—2023年中国知网(CNKI)数据库收录的1146篇城市地下空间开发利用领域文献,基于CiteSpace和VOSviewer文献计量软件从发文量趋势演化、作者和机构合作构成网络、关键词共现及聚类特征进行可视化热度分析。研究结果表明:在发文量趋势演化方面,随着时间的推移,城市地下空间开发利用领域的文献数量总体呈现上升趋势,反映出该领域在我国城市化建设和能源资源转型过程中的重要性日益凸显,受到越来越多的关注和研究;从作者和机构合作构成网络来看,部分核心作者和研究机构在该领域发挥了重要的引领作用,但整体合作网络仍有进一步拓展和深化的空间,需要加强跨机构、跨地域的合作交流,以推动该领域研究的全面发展;通过关键词共现及聚类特征分析,明确了该领域的研究热点主要集中在地下交通、地下商业、人防工程、地下综合管廊等方面,同时也呈现出向智能化管理、生态环保、可持续发展等方向拓展的趋势,为未来的研究提供了方向指引。研究结果对安全生产意义显著,可精准防控风险、强化协同合作、助力规划安全布局,为地下空间开发筑牢安全根基。 展开更多
关键词 城市地下空间 开发利用 Citespace和VOSviewer 文献计量 知识图谱
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Study of bonding layer for integrated structure of space gravitational wave detector telescope
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作者 ZHAO Hong-chao LIU Chang +2 位作者 ZHOU Wen-ke ZHU Han-bin CHEN Wen-duo 《中国光学(中英文)》 北大核心 2025年第3期715-724,共10页
To detect space gravitational waves in the extremely low-frequency band,the telescope and optic-al platform require high stability and reliability.However,the cantilevered design presents challenges,espe-cially in the... To detect space gravitational waves in the extremely low-frequency band,the telescope and optic-al platform require high stability and reliability.However,the cantilevered design presents challenges,espe-cially in the glass-metal hetero-bonding process.This study focuses on the analysis and experimental re-search of the bonding layer in the integrated structure.By optimizing the structural configuration and select-ing suitable bonding processes,the reliability of the telescope system is enhanced.The research indicates that using J-133 adhesive achieves the best performance,with a bonding layer thickness of 0.30 mm and a metal substrate surface roughness of Ra 0.8.These findings significantly enhance the reliability of the optical sys-tem while minimizing potential risks. 展开更多
关键词 space gravitational-wave detector integrated structure glass-metal hetero-bonding
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习近平生态文明思想研究的演进、现状与展望——基于CNKI CSSCI文献的cite space知识图谱可视化分析
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作者 胡桂银 《东南大学学报(哲学社会科学版)》 北大核心 2025年第S1期9-13,共5页
习近平生态文明思想是习近平新时代中国特色社会主义思想体系的关键构成。目前对习近平生态文明思想的定量分析缺失。基于此,借助cite space可视化软件,对CNKI数据库篇名为“习近平生态文明思想”的364篇CSSCI文献进行分析。结果显示,... 习近平生态文明思想是习近平新时代中国特色社会主义思想体系的关键构成。目前对习近平生态文明思想的定量分析缺失。基于此,借助cite space可视化软件,对CNKI数据库篇名为“习近平生态文明思想”的364篇CSSCI文献进行分析。结果显示,研究领域主要呈现出增长—回落—再增长的演进趋势,表现为四个研究阶段。研究领域内现状一是研究者层面未形成高产作者群和高产作者;二是研究内容范围较广;三是研究热点较为集中。基于以上结果,分别从三方面展望未来对习近平生态文明思想研究,一是在研究群体方面,着力构建完善的习近平生态文明思想研究学术共同体。二是在研究主题方面,大力推动习近平生态文明思想的多学科融合与阐述。三是在世界意义方面,高度重视习近平生态文明思想的国际意义阐释。 展开更多
关键词 习近平生态文明思想 cite space 知识图谱 可视化分析
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基于CiteSpace的小麦赤霉病研究热点与趋势分析
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作者 关卫东 金牧兰 +2 位作者 李芮 李邦耀 董文成 《麦类作物学报》 北大核心 2025年第4期510-520,共11页
小麦赤霉病研究对于农业生产和保障全球粮食安全具有重要意义。为深入了解小麦赤霉病研究进展和动态前沿,运用CiteSpace软件,对近20年来Web of Science核心合集中1236篇小麦赤霉病研究文献进行系统分析。结果表明,近20年来小麦赤霉病研... 小麦赤霉病研究对于农业生产和保障全球粮食安全具有重要意义。为深入了解小麦赤霉病研究进展和动态前沿,运用CiteSpace软件,对近20年来Web of Science核心合集中1236篇小麦赤霉病研究文献进行系统分析。结果表明,近20年来小麦赤霉病研究发文量总体呈上升趋势,美国以345篇的发文量位居榜首,中美、中英、中加等国际合作网络较为紧密。研究内容主要集中在病原菌特性、病害防治技术、抗病品种选育等方面;当前研究热点以抗病性鉴定、分子标记辅助选择、新型生物防治剂开发等为主;热门技术方法涉及分子代谢组学、基因组学、遥感监测技术等。展望未来,小麦赤霉病研究将更加注重跨学科合作,致力于开发高效、环保的病害防控策略,以应对全球粮食安全挑战。 展开更多
关键词 小麦赤霉病 Cite space软件 信息可视化 研究趋势
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Block sparse compressed sensing with frames:Null space property and l_(2)/l_(q)(0
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作者 WU Fengong ZHONG Penghong QIN Yuehai 《中山大学学报(自然科学版)(中英文)》 北大核心 2025年第3期173-182,共10页
This paper explores the recovery of block sparse signals in frame-based settings using the l_(2)/l_(q)-synthesis technique(0<q≤1).We propose a new null space property,referred to as block D-NSP_(q),which is based ... This paper explores the recovery of block sparse signals in frame-based settings using the l_(2)/l_(q)-synthesis technique(0<q≤1).We propose a new null space property,referred to as block D-NSP_(q),which is based on the dictionary D.We establish that matrices adhering to the block D-NSP_(q)condition are both necessary and sufficient for the exact recovery of block sparse signals via l_(2)/l_(q)-synthesis.Additionally,this condition is essential for the stable recovery of signals that are block-compressible with respect to D.This D-NSP_(q)property is identified as the first complete condition for successful signal recovery using l_(2)/l_(q)-synthesis.Furthermore,we assess the theoretical efficacy of the l2/lq-synthesis method under conditions of measurement noise. 展开更多
关键词 Compressed sensing block sparse l2/lq-synthesis method null space property
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MRI相位导航技术下2D T2-TSE与3D T2-SPACE序列在疑似隐匿性脊髓栓系综合征俯卧位扫描中的应用价值对比
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作者 李鹏 杨立棋 +5 位作者 徐守军 张艳慧 林飞飞 熊海芮 孙金磊 向葵 《磁共振成像》 北大核心 2025年第1期158-164,共7页
目的对比MRI相位导航技术下二维T2加权快速自旋回波(two dimensional T2 weighted imaging turbo spin echo,2D T2-TSE)序列与三维T2加权可变翻转角快速自旋回波(three dimensional T2 weighted imaging sampling perfection with appli... 目的对比MRI相位导航技术下二维T2加权快速自旋回波(two dimensional T2 weighted imaging turbo spin echo,2D T2-TSE)序列与三维T2加权可变翻转角快速自旋回波(three dimensional T2 weighted imaging sampling perfection with application optimized contrast using different flip angle evolution,3D T2-SPACE)序列在疑似隐匿性脊髓栓系综合征(occult tethered cord syndrome,OTCS)俯卧位扫描中的图像质量和临床应用价值。材料与方法回顾性分析2023年1月至2023年10月在我院接受MRI检查的疑似OTCS的6岁以下患者30例,均采用相位导航技术下俯卧位2D T2-TSE和3D T2-SPACE序列进行检查。根据所得图像整体质量、脊髓圆锥显示、马尾神经及终丝显示、蛛网膜下腔脑脊液信号显示、背景噪声显示情况进行主观评分,记录扫描时间,计算椎管内的图像信噪比(signal-to-noise ratio,SNR)和对比噪声比(contrast-to-noise ratio,CNR)。比较两种序列的图像质量的主观评分、扫描时间、椎管内SNR与CNR的客观分析。分别采用配对t检验、Mann-Whitney U检验,将两种检查方法的评估结果进行对比分析。通过Kappa检验分别评估两名医师主观评分的一致性,以及两名技师客观定量分析的一致性。结果图像质量的主观评分中,两名医师的评分一致性较强(Kappa=0.794,P<0.001),3D T2-SPACE序列图像整体质量、马尾神经及终丝显示、蛛网膜下腔脑脊液信号显示以及背景噪声显示评分均高于2D T2-TSE序列(Z=-2.305、-4.242、-3.453、-2.201,P均<0.05),在脊髓圆锥显示上,2D T2-TSE与3D T2-SPACE序列一致(Z=-0.948,P>0.05)。客观定量分析中,两名技师对椎管内SNR与CNR测量结果的一致性很强(Kappa=0.851、0.734,P均<0.001),2D T2-TSE对比3D T2-SPACE序列,两次测量的数据分析结果中3D T2-SPACE序列椎管内SNR和CNR均优于2D T2-TSE序列(第一次测量SNR与CNR:t=-3.058、-3.703;第二次测量SNR与CNR:t=-2.981、-2.965,P均<0.05)。3D T2-SPACE序列扫描时间较2D T2-TSE序列扫描时间长[(183.67±34.89)s vs.(120.53±27.93)s,t=-10.087,P<0.001]。结论在疑似OTCS患者的俯卧位MRI检查中,相位导航技术下的3D T2-SPACE序列相比2D T2-TSE序列可以提供更优良的椎管内图像质量、更小的FOV与体素,为临床诊治提供更多可靠信息。 展开更多
关键词 脊髓栓系综合征 隐匿性 三维T2加权可变翻转角快速自旋回波 俯卧位 相位导航技术 儿童 磁共振成像
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Microwave power transmission technologies for space solar power station
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作者 YANG Bo SHINOHARA Naoki 《中国空间科学技术(中英文)》 北大核心 2025年第2期1-14,共14页
The microwave wireless power transmission technologies for space solar power station are a crucial field in the international space sector,where various countries are competing in its development.This paper surveys th... The microwave wireless power transmission technologies for space solar power station are a crucial field in the international space sector,where various countries are competing in its development.This paper surveys the research experiments and development efforts related to space solar power stations and microwave wireless power transmission technologies worldwide.The objective is to assess the progress and current state of this technological foundation,determine the necessary focus for developing high-power microwave wireless power transmission technology,and provide clarity on the direction of future technology development in these areas.Finally,a distributed space solar power station plan that is immediately feasible is proposed. 展开更多
关键词 microwave power transmission space solar power station wireless power transfer microwave transmitter phased array rectenna array
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基于Cite Space的工业遗产景观研究现状与可视化分析
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作者 于美慧 齐佳 《现代园艺》 2025年第2期44-45,48,51,共4页
近年来,工业遗产保护与更新改造受到政府部门与学者的广泛关注。工业遗产作为城市发展的见证,是城市文化的组成部分,改造后的工业遗产更是变成了城市独特的“打卡区域”。为了进一步了解工业遗产景观领域的研究进展、热点及趋势,以中国... 近年来,工业遗产保护与更新改造受到政府部门与学者的广泛关注。工业遗产作为城市发展的见证,是城市文化的组成部分,改造后的工业遗产更是变成了城市独特的“打卡区域”。为了进一步了解工业遗产景观领域的研究进展、热点及趋势,以中国知网2010-2023年关于我国工业遗产景观研究的论文为研究数据,利用CiteSpace6.2.R 4软件进行可视化分析,通过应用相应的知识图谱,梳理出研究热点现状,并预测未来的研究方向,以期为我国工业遗产景观的研究和发展提供指导。 展开更多
关键词 工业遗产 景观 Cite space
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Research on the protection mechanism of methane explosion in underground space by flexible construction
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作者 Xianqi Duan Yulong Duan +3 位作者 Zishuang Zhang Jun Long Yaqiao Yang Rui Lang 《Defence Technology(防务技术)》 2025年第4期169-183,共15页
Urban growth has promoted the use of underground spaces,where explosion accidents can be catastrophic.In this study,we investigated the effect of placing flexible construction in front of rigid obstacles on methane ex... Urban growth has promoted the use of underground spaces,where explosion accidents can be catastrophic.In this study,we investigated the effect of placing flexible construction in front of rigid obstacles on methane explosion protection by using an experimental platform and adjusting the blockage rate and spacing of the obstacles.It aims to reduce the risk of gas explosions in urban underground spaces.The results of the study show that the flame propagation peak speed and peak overpressure are reduced with the decrease in the blocking rate of the flexible obstacle when the blocking rate of the flexible obstacle is less than or equal to the blocking rate of the rigid obstacle,with the decrease in the spacing,the better the protection effect of the methane explosion.When the blockage rate of the flexible obstacle is greater than the blockage rate of the rigid obstacle and spacing is less than the height of the flexible obstacle,rigid and flexible obstacles are connected as a whole,increasing the strength of the explosion.This study can provide a theoretical basis and scientific guidance for optimizing rigid and flexible object hybrid layouts and methane explosion protection technology in urban underground spaces. 展开更多
关键词 Explosion protection Flexible construction Urban underground space Methane explosions
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Experimental study on the TNT equivalence for blast parameters in a confined space
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作者 Yu-lei Zhang Yan Liu +5 位作者 Pu Song Hao-zhe Liang Di Yang Lu Han Hai-yan Jiang Kai Zhong 《Defence Technology(防务技术)》 2025年第6期238-249,共12页
The concept of TNT(Trinitrotoluene,C_7H_5N_3O_6)equivalence is often invoked to evaluate the performance and predict the explosion parameters of different types of explosives.However,due to its low prediction accuracy... The concept of TNT(Trinitrotoluene,C_7H_5N_3O_6)equivalence is often invoked to evaluate the performance and predict the explosion parameters of different types of explosives.However,due to its low prediction accuracy and limited application range,the use of TNT equivalence for predicting explosion parameters in a confined space is rare.Compared with explosions in free fields,the process of explosive energy release in a confined space is closely related to various factors such as oxygen balance,combustible components content,and surrounding oxygen content.Studies have shown that in a confined space,negative oxygen balance explosives react with surrounding oxygen during afterburning,resulting in additional energy release and enhanced blast effects.The mechanism of energy release during afterburning is highly complex,making it challenging to determine the TNT equivalence for blast effects in a confined space.Therefore,this remains an active area of research.In this study,internal blast experiments were conducted using TNT and three other explosives under both air and N_2(Nitrogen)conditions to obtain explosion parameters including blast wave overpressure,quasi-static pressure,and temperature.The influences of oxygen balance and external oxygen content on energy release are analyzed.The author proposes principles for determining TNT equivalence for internal explosions while verifying the accuracy of obtained blast parameters through calculations based on TNT equivalence.These findings can serve as references for predicting blast performance. 展开更多
关键词 Explosion in confined space AFTERBURNING Oxygen balance Blast parameters TNT equivalence
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