期刊文献+
共找到175,609篇文章
< 1 2 250 >
每页显示 20 50 100
基于Space P和K-means的货运航司航线网络特征分析研究
1
作者 罗凤娥 卫昌波 +1 位作者 韩晓彤 郭玲玉 《现代电子技术》 北大核心 2026年第1期102-107,共6页
针对航空货运行业的迅速扩张,航空货运网络结构变得更加复杂,文中通过Space P建模方法构建了货运航空公司航线网络模型,并运用K-means聚类算法对网络进行了深入分析。选取度、平均路径长度、聚类系数和中间度等关键网络特性指标对航线... 针对航空货运行业的迅速扩张,航空货运网络结构变得更加复杂,文中通过Space P建模方法构建了货运航空公司航线网络模型,并运用K-means聚类算法对网络进行了深入分析。选取度、平均路径长度、聚类系数和中间度等关键网络特性指标对航线网络进行层次化分类,揭示了网络的复杂特征和层次结构。通过仿真实验评估了网络的小世界特性,并利用轮廓系数得到不同K值下的聚类结果,进而确定最优聚类结果。同时,模拟了航线网络在遭受攻击时的鲁棒性,实验结果表明:在航线网络较为脆弱的情况下,该方法为货运航司航线网络的优化和抗风险能力的提升提供了重要参考。 展开更多
关键词 航空货运 space P 航线网络 复杂网络 聚类算法 网络特征
在线阅读 下载PDF
近二十年国内外图书馆学习空间研究的比较分析——基于Citespace和Bicomb的可视化计量分析
2
作者 诸葛晴怡 《建筑与文化》 2026年第2期165-168,共4页
文章基于CNKI、Web of Science两大数据库2005—2024年收录的图书馆学习空间研究文献,运用CiteSpace、Bicomb、SPSS软件进行可视化分析。结果显示,国外研究以技术驱动创新为主导,聚焦智能化技术与跨学科应用;而国内研究呈现理论创新与... 文章基于CNKI、Web of Science两大数据库2005—2024年收录的图书馆学习空间研究文献,运用CiteSpace、Bicomb、SPSS软件进行可视化分析。结果显示,国外研究以技术驱动创新为主导,聚焦智能化技术与跨学科应用;而国内研究呈现理论创新与实践探索并重,通过大数据、AI等技术形成本土化解决方案。文章提出通过数字技术与人文关怀的平衡发展、国际化视野与本土化创新的有机结合、理论研究与实践应用的深度融合,为我国图书馆学习空间的研究提供借鉴与参考。 展开更多
关键词 图书馆学习空间 知识图谱 可视化分析 比较分析
在线阅读 下载PDF
基于CiteSpace的国内高原特色农业发展研究领域文献计量及可视化分析
3
作者 赖胜君 贾小永 +1 位作者 谭华 程静 《陕西农业科学》 2026年第2期116-122,共7页
本研究基于CNKI收录数据,检索出2014-2023年关于高原特色农业发展的文章,通过CiteSpace软件进行可视化分析。本研究共将279篇文献纳入可视化分析,国内高原特色农业发展研究发文量呈现总体下滑的趋势。发文期刊以《云南农业》杂志为主;... 本研究基于CNKI收录数据,检索出2014-2023年关于高原特色农业发展的文章,通过CiteSpace软件进行可视化分析。本研究共将279篇文献纳入可视化分析,国内高原特色农业发展研究发文量呈现总体下滑的趋势。发文期刊以《云南农业》杂志为主;研究的主要阵地以西南地区的农业科研院所和高等农业院校为主;研究主题多聚焦于高原特色农业发展的对策、路径研究。因此我国高原特色农业发展研究领域亟待加大研究资金投入和研究力度,扩宽合作领域,聚焦热点和前沿,推动多学科交叉融合研究,促进我国高原特色农业发展研究领域的进步。 展开更多
关键词 高原 特色农业 农业发展 可视化分析 Cite space
在线阅读 下载PDF
Adaptive-length data-driven predictive control for post-operation of space robot non-cooperative target capture with disturbances 被引量:1
4
作者 Peiji WANG Bicheng CAI +2 位作者 Chengfei YUE Yong ZHAO Weiren WU 《Chinese Journal of Aeronautics》 2026年第2期485-498,共14页
This paper solves the problem of model-free dual-arm space robot maneuvering after non-cooperative target capture under high control quality requirements.The explicit system model is unavailable,and the maneuvering mi... This paper solves the problem of model-free dual-arm space robot maneuvering after non-cooperative target capture under high control quality requirements.The explicit system model is unavailable,and the maneuvering mission is disturbed by the measurement noise and the target adversarial behavior.To address these problems,a model-free Combined Adaptive-length Datadriven Predictive Controller(CADPC)is proposed.It consists of a separated subsystem identification method and a combined predictive control strategy.The subsystem identification method is composed of an adaptive data length,thereby reducing sensitivity to undetermined measurement noises and disturbances.Based on the subsystem identification,the combined predictive controller is established,reducing calculating resource.The stability of the CADPC is rigorously proven using the Input-to-State Stable(ISS)theorem and the small-gain theorem.Simulations demonstrate that CADPC effectively handles the model-free space robot post operation in the presence of significant disturbances,state measurement noise,and control input errors.It achieves improved steady-state accuracy,reduced steady-state control consumption,and minimized control input chattering. 展开更多
关键词 Combined control Data-driven predictive control Post operation Predictive control systems space non-cooperative target capture
原文传递
Hyponormal Block Toeplitz Operators on the Weighted Bergman Space with Circulant Symbols
5
作者 FU Guangyang ZHOU Jiang 《数学进展》 北大核心 2026年第1期183-191,共9页
In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and... In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and G(z)=∑^(N)_(i)=1 A_(−i)z^(i),A_(i)ae culants. 展开更多
关键词 block Toeplitz operator hyponormal weighted Bergman space CIRCULANT COMMUTATOR
原文传递
Mixed Quasi-martingale Hardy Spaces
6
作者 ZHANG Chuanzhou LI Shimeng HE Zhibin 《应用数学》 北大核心 2026年第1期221-231,共11页
In this article,we conduct a study on mixed quasi-martingale Hardy spaces that are defined by means of the mixed L_(p)-norm.By utilizing Doob’s inequalities,we explore the atomic decomposition and quasi-martingale in... In this article,we conduct a study on mixed quasi-martingale Hardy spaces that are defined by means of the mixed L_(p)-norm.By utilizing Doob’s inequalities,we explore the atomic decomposition and quasi-martingale inequalities of mixed quasi-martingale Hardy spaces.Moreover,we furnish sufficient conditions for the boundedness ofσ-sublinear operators in these spaces.These findings extend the existing conclusions regarding mixed quasi-martingale Hardy spaces defined with the help of the mixed L_(p)-norm. 展开更多
关键词 Mixed quasi-martingale Hardy space Atomic Decomposition σ-sublinear operator
在线阅读 下载PDF
Triboelectric Nanogenerators for Future Space Missions
7
作者 Rayyan Ali Shaukat Muhammad Muqeet Rehman +4 位作者 Maryam Khan Rui Chang Carlo Saverio Iorio Yarjan Abdul Samad Yijun Shi 《Nano-Micro Letters》 2026年第3期630-684,共55页
Space exploration is significant for scientific innovation,resource utilization,and planetary security.Space exploration involves several systems including satellites,space suits,communication systems,and robotics,whi... Space exploration is significant for scientific innovation,resource utilization,and planetary security.Space exploration involves several systems including satellites,space suits,communication systems,and robotics,which have to function under harsh space conditions such as extreme temperatures(−270 to 1650℃),microgravity(10^(-6)g),unhealthy humidity(<20%RH or>60%RH),high atmospheric pressure(~1450 psi),and radiation(4000–5000 mSv).Conventional energy-harvesting technologies(solar cells,fuel cells,and nuclear energy),that are normally used to power these space systems have certain limitations(e.g.,sunlight dependence,weight,degradation,big size,high cost,low capacity,radioactivity,complexity,and low efficiency).The constraints in conventional energy resources have made it imperative to look for non-conventional yet efficient alternatives.A great potential for enhancing efficiency,sustainability,and mission duration in space exploration can be offered by integrating triboelectric nanogenerators(TENGs)with existing energy sources.Recently,the potential of TENG including energy harvesting(from vibrations/movements in satellites and spacecraft),self-powered sensing,and microgravity,for multiple applications in different space missions has been discussed.This review comprehensively covers the use of TENGs for various space applications,such as planetary exploration missions(Mars environment monitoring),manned space equipment,In-orbit robotic operations/collision monitoring,spacecraft’s design and structural health monitoring,Aeronautical systems,and conventional energy harvesting(solar and nuclear).This review also discusses the use of self-powered TENG sensors for deep space object perception.At the same time,this review compares TENGs with conventional energy harvesting technologies for space systems.Lastly,this review talks about energy harvesting in satellites,TENG-based satellite communication systems,and future practical implementation challenges(with possible solutions). 展开更多
关键词 Triboelectric nanogenerators(TENGs) space missions Sustainable energy harvesting Harsh space conditions Selfpowered sensors Satellite missions
在线阅读 下载PDF
THE BOUNDEDNESS OF INHOMOGENEOUS CALDERÓN-ZYGMUND CONVOLUTION OPERATORS ON LOCAL PRODUCT HARDY SPACES
8
作者 Shaoyong HE Jiecheng CHEN 《Acta Mathematica Scientia》 2026年第1期99-111,共13页
It is well known that the inhomogeneous Calderón-Zygmund convolution operators are bounded on the local Hardy spaces.In this paper,we prove that these operators are bounded on the local product Hardy spaces and t... It is well known that the inhomogeneous Calderón-Zygmund convolution operators are bounded on the local Hardy spaces.In this paper,we prove that these operators are bounded on the local product Hardy spaces and the Lipschitz spaces.The key ideas used here are the discrete local Calderón identity and a density argument for the inhomogeneous product Lipschitz spaces in the weak sense. 展开更多
关键词 local Hardy space Lipschitz space inhomogeneous Calderón-Zygmund operator discrete Calderón identity
在线阅读 下载PDF
Sky's the Limit In Wenchang, commercial aerospace is soaring to new heights, propelled by Hainan FTP's island-wide special customs operations
9
作者 Xia Yuanyuan 《China Report ASEAN》 2026年第3期30-31,共2页
At 11:00 p.m. on January 13, 2026, floodlights illuminated the launch pad at the Hainan Commercial Space Launch Site in Wenchang,south China’s Hainan Province. A Long March-8A (CZ-8A) carrier rocket lifted off with a... At 11:00 p.m. on January 13, 2026, floodlights illuminated the launch pad at the Hainan Commercial Space Launch Site in Wenchang,south China’s Hainan Province. A Long March-8A (CZ-8A) carrier rocket lifted off with a steady roar, its exhaust lighting up the night sky as it delivered a satellite into its designated orbit.The development of China’s first commercial space launch site has been striking. Since its inaugural launch in2024, it has completed 11 missions in less than 14 months—each a success. 展开更多
关键词 Long March space launch site satellite launch special customs operations commercial space launch launch pad Hainan Wenchang commercial aerospace
在线阅读 下载PDF
A GENERALIZED HILBERT OPERATOR ACTING ON HARDY SPACES
10
作者 Huiling CHEN Shanli YE 《Acta Mathematica Scientia》 2026年第1期145-163,共19页
Letα>0 and letμbe a positive Borel measure on the interval[0,1).The Hankel matrix■with entries■induces,formally,the generalized-Hilbert operator■where f(z)■is an analytic function in D.This article is devoted... Letα>0 and letμbe a positive Borel measure on the interval[0,1).The Hankel matrix■with entries■induces,formally,the generalized-Hilbert operator■where f(z)■is an analytic function in D.This article is devoted to study the measuresμfor which Hμ,αis a bounded(resp.,compact)operator from Hp(0<p≤1)into H^(p)(1≤q<∞).We also study the analogous problem in the Hardy spaces H^(p)(1≤p≤2).Finally,we obtain the essential norm of H_(μ,α)from H^(p)(0<p≤1)into H^(p)(1≤q<∞). 展开更多
关键词 Hilbert operator Hardy space Carleson measure essential norm
在线阅读 下载PDF
基于Cite Space文献计量分析的学分银行研究现状与展望
11
作者 刘云龙 《太原城市职业技术学院学报》 2026年第1期66-68,共3页
以2002—2022年核心期刊和CSSCI数据库中关于学分银行研究的523篇文献为研究对象。基于Cite Space中关键词共现分析、关键词共现的时区分析绘出学分银行研究知识图谱。数据显示以下两点结论:学分银行研究演变规律分为三个阶段,分别为初... 以2002—2022年核心期刊和CSSCI数据库中关于学分银行研究的523篇文献为研究对象。基于Cite Space中关键词共现分析、关键词共现的时区分析绘出学分银行研究知识图谱。数据显示以下两点结论:学分银行研究演变规律分为三个阶段,分别为初始阶段、繁荣阶段和深入阶段。学分银行研究主要围绕学分认定和学分转换两个主题延伸,两个主题之间彼此相互融合;学分银行研究前沿指向于高突变度的关键词如开放大学、终身教育、社区教育、资历框架和职业教育。未来时期内,学分银行研究要着重“学分银行”和“资历框架”的研究具有一定的相关性,加强统一的协调机制、相关法律制度、成果转换为学分的标准研究;应着重多学科融合,构建学分银行的研究理论方法体系。 展开更多
关键词 学分银行 Cite space 知识图谱 可视化
在线阅读 下载PDF
Collision risk assessment for constellation satellites based on a space debris environment topological network model
12
作者 Yurun YUAN Jingrui ZHANG +2 位作者 Keying YANG Lincheng LI Hao WU 《Chinese Journal of Aeronautics》 2026年第2期472-484,共13页
In recent years,the rapid development of mega-constellations has significantly exacerbated the deterioration of the space debris environment,posing substantial and escalating threats to the safety of spacecraft.This s... In recent years,the rapid development of mega-constellations has significantly exacerbated the deterioration of the space debris environment,posing substantial and escalating threats to the safety of spacecraft.This study aims to explore the complex evolution of the space debris environment and assess the collision risks associated with spacecraft.First,a space debris environment topological network model is proposed,which incorporates interdisciplinary methods from topological networks,fluid mechanics,and spacecraft dynamics.This model enables a structured representation of the relationships among space objects and provides rapid predictions of the space debris environment.Then,a collision probability algorithm based on the topological network model is introduced.This algorithm inherits the efficiency advantages of the topological network model and has been validated for reliability through comparison with the classical ESA’s DRAMA software.Finally,based on the above models,the collision risks of constellation satellites in Low Earth Orbit(LEO)are analyzed,including both operational and deorbit processes.The study reveals that constellation satellites face a much higher risk of internal collisions with satellites from the same constellation during operations than that with other space objects.Additionally,during the satellite deorbit process,the collision risk peaks when satellites traverse the operational region of Starlink satellites. 展开更多
关键词 Collision probability Computing resource CONSTELLATION space debris Topological network model
原文传递
Color of the Year 2026: Cloud Dancer, a hue of serenity and space
13
《China Textile》 2026年第1期54-55,共2页
The Pantone Color of the Year 2026,PANTONE 11-4201 Cloud Dancer,has been introduced as a soft,lofty white symbolizing calm and clarity in an increasingly noisy world.This gentle shade invites a sense of peace and spac... The Pantone Color of the Year 2026,PANTONE 11-4201 Cloud Dancer,has been introduced as a soft,lofty white symbolizing calm and clarity in an increasingly noisy world.This gentle shade invites a sense of peace and spaciousness,encouraging focus and creating room for creativity and reflection.Cloud Dancer embodies a desire for simplicity and renewal-a blank canvas that allows our minds to wander and new ideas to take shape.Its expansive presence fosters environments where tranquility meets inspiration,offering visual calm that supports wellbeing and mental lightness. 展开更多
关键词 pantone color SERENITY space clarity creativity blank canvas reflection cloud dancerhas
在线阅读 下载PDF
REFINED BOHR INEQUALITIES AND A REFINED BOHR-ROGOSINSKI INEQUALITY ON COMPLEX BANACH SPACES
14
作者 Molla Basir AHAMED Sabir AHAMMED Hidetaka HAMADA 《Acta Mathematica Scientia》 2026年第1期19-38,共20页
In this paper,we first establish refined versions of the Bohr inequalities for the class of holomorphic functions from the unit ball BX of a complex Banach space X into ℂ.As applications,we will establish refined Bohr... In this paper,we first establish refined versions of the Bohr inequalities for the class of holomorphic functions from the unit ball BX of a complex Banach space X into ℂ.As applications,we will establish refined Bohr inequalities of functional type or of norm type for holomorphic mappings with lacunary series on the unit ball BX with values in higher dimensional spaces.Next,we obtain the Bohr-Rogosinski inequality for the class of holomorphic functions on BX.In addition,we establish an improved version of the Bohr inequality for holomorphic functions on BX.All the results are proved to be sharp. 展开更多
关键词 Banach spaces Bohr inequality Bohr-Rogosinski inequality homogeneous polynomial expansion Lacunary series
在线阅读 下载PDF
Design of the support structure for a space-based concave thin mirror
15
作者 Ming Bu Kejun Wang 《Astronomical Techniques and Instruments》 2026年第1期55-63,共9页
The neutral surface of a concave thin mirror is too close to the mirror surface,which makes it difficult to effectively mount the flexible structure and increases the mirror surface shape error.To address this problem... The neutral surface of a concave thin mirror is too close to the mirror surface,which makes it difficult to effectively mount the flexible structure and increases the mirror surface shape error.To address this problem,we design a flexible support structure including connectors,a support plate,and flexible structures,and construct an equivalent mirror by installing connectors and a support plate on the back of the mirror.While ensuring that the neutral surface of the equivalent mirror is moved away from the mirror surface,we optimize the support structure so that the rotary center of the flexible structure is located on the neutral surface of the equivalent mirror,avoiding the tilting moment.Following design and modeling of the structure,we analyze the static and dynamic characteristics using a finite element simulation,finding a root-mean-square(RMS)value for the surface shape error of 9.28 nm under the coupled effects of 1g gravity load,4℃ temperature rise,and 0.005 mm unevenness assembly error,with a fundamental frequency of 170.75 Hz,which all meet the design requirements.Finally,we carry out a surface shape error test of the mirror assembly,confirming it to meet the design index requirement of the mirror assembly.Simulation and test results verify the reliability and effectiveness of our proposed support structure. 展开更多
关键词 space optics Thin mirror Flexible support Neutral surface Surface shape error
在线阅读 下载PDF
A NORM INEQUALITY ON NONCOMMUTATIVE SYMMETRIC SPACES RELATED TO A QUESTION OF BOURIN
16
作者 Jinchen LIU Kan HE Xingpeng ZHAO 《Acta Mathematica Scientia》 2026年第1期62-68,共7页
In this note,we study a question introduced by Bourin[1]and extend the conclusion from[2]to the case of operators on noncommutative fully symmetric spaces.The conclusion is as follows.Let 0≤x,y∈E(M),If t∈[0,1/4]∪[... In this note,we study a question introduced by Bourin[1]and extend the conclusion from[2]to the case of operators on noncommutative fully symmetric spaces.The conclusion is as follows.Let 0≤x,y∈E(M),If t∈[0,1/4]∪[3/4,1],then∥x^(t)y^(1-t)+ytx^(1-t)∥E(M)≤2^(2t-3/2)∥x+y∥E(M). 展开更多
关键词 τ-measurable operators fully symmetric spaces von Neumann algebra
在线阅读 下载PDF
UNIFORMLY COPIES OF l_(P)^(N) IN THE SPACES OF POLYNOMIALS
17
作者 Dumitru POPA 《Acta Mathematica Scientia》 2026年第1期112-118,共7页
Let n≥2 be a natural number,1≤p≤∞and X a Banach space.We prove that if X^(*)containsλ-uniformly copies of l^(k)^(p),then:P(^(n)X) contains cKλ^(n)-uniformly copies of■.in the case p^(*)>n(ii)P(^(n)X) contain... Let n≥2 be a natural number,1≤p≤∞and X a Banach space.We prove that if X^(*)containsλ-uniformly copies of l^(k)^(p),then:P(^(n)X) contains cKλ^(n)-uniformly copies of■.in the case p^(*)>n(ii)P(^(n)X) containsλ^(n)-uniformly copies of l^(k)_(∞)in the case p^(*)≤n.This complete a result of S.Dineen’s from 1995. 展开更多
关键词 polynomials on Banach spaces uniformly copies of lnp finitely represented
在线阅读 下载PDF
NONLINEAR RIEMANN AND HILBERT BOUNDARY VALUE PROBLEMS WITH SQUARE ROOTS IN VARIABLE EXPONENT SPACES
18
作者 Yajun Hu Fuli He 《Acta Mathematica Scientia》 2026年第1期1-18,共18页
In this paper,we study the nonlinear Riemann boundary value problem with square roots that is represented by a Cauchy-type integral with kernel density in variable exponent Lebesgue spaces.We discuss the odd-order zer... In this paper,we study the nonlinear Riemann boundary value problem with square roots that is represented by a Cauchy-type integral with kernel density in variable exponent Lebesgue spaces.We discuss the odd-order zero-points distribution of the solutions and separate the single valued analytic branch of the solutions with square roots,then convert the problem to a Riemann boundary value problem in variable exponent Lebesgue spaces and discuss the singularity of solutions at individual zeros belonging to curve.We consider two types of cases those where the coefficient is Hölder and those where it is piecewise Hölder.Then we solve the Hilbert boundary value problem with square roots in variable exponent Lebesgue spaces.By discussing the distribution of the odd-order zero-points for solutions and the method of symmetric extension,we convert the Hilbert problem to a Riemann boundary value problem.The equivalence of the transformation is discussed.Finally,we get the solvable conditions and the direct expressions of the solutions in variable exponent Lebesgue spaces. 展开更多
关键词 boundary value problem Cauchy-type integral variable exponent spaces non-linearity piecewise Lyapunov curve
在线阅读 下载PDF
λ-BIHARMONIC HYPERSURFACES IN 6-DIMENSIONAL PSEUDO-RIEMANNIAN SPACE FORMS
19
作者 DUAN Zhen-ping YANG Chao +1 位作者 LIU Jian-cheng CHEN Jia-rui 《数学杂志》 2026年第1期1-19,共19页
In this paper,we studyλ-biharmonic hypersurfaces M_(r)^(5) of 6-dimensional pseudo Riemannian space form N_(p)^(6)(c)with the indexs 0≤p≤6,r=p−1 or p,and constant curvature c.It was proved that if the shape operato... In this paper,we studyλ-biharmonic hypersurfaces M_(r)^(5) of 6-dimensional pseudo Riemannian space form N_(p)^(6)(c)with the indexs 0≤p≤6,r=p−1 or p,and constant curvature c.It was proved that if the shape operator of M_(r)^(5) is diagonalizable,then the mean curvature is a constant.As an application,we find some types of biharmonic hypersurfaces of N_(p)^(6)(c)are minimal. 展开更多
关键词 λ-biharmonic hypersurface pseudo-Riemannian space form constant mean curvature shape operator minimal
在线阅读 下载PDF
Earth Space Lab赋能初中地理抽象概念教学研究——以“地球的运动”为例
20
作者 吴燕萍 马蒙 叶淑红 《地理教育》 2026年第2期24-28,共5页
数字化赋能教学已成为当前教学的新趋势,本文借助Earth Space Lab程序赋能“地球的运动”教学,帮助学生从本质上理解较为抽象的地理概念,同时,基于Earth Space Lab的教学不仅能实现学生对抽象概念的熟练掌握与灵活应用,促进作业质量与... 数字化赋能教学已成为当前教学的新趋势,本文借助Earth Space Lab程序赋能“地球的运动”教学,帮助学生从本质上理解较为抽象的地理概念,同时,基于Earth Space Lab的教学不仅能实现学生对抽象概念的熟练掌握与灵活应用,促进作业质量与学习效果显著提升,还能进一步提升学生学习兴趣、地理实践力与综合思维,促进其地理核心素养的培育。 展开更多
关键词 Earth space Lab 地理抽象概念教学 地球的运动
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