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Compactness of Fractional Calderón Type Commutators on Morrey Spaces
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作者 LI Aobo MEI Ting WEI Qi 《数学进展》 北大核心 2025年第4期858-870,共13页
In this paper,the authors study the fractional Calderon type commutator T_(Ω,α)^(A)and its maximal operator M_(Ω,α)^(A)with kernels having some kinds of Log-type Dini-condition and obtain the compactness on Morrey... In this paper,the authors study the fractional Calderon type commutator T_(Ω,α)^(A)and its maximal operator M_(Ω,α)^(A)with kernels having some kinds of Log-type Dini-condition and obtain the compactness on Morrey spaces L^(p,λ)(R^(n)). 展开更多
关键词 Calderón type commutator compactness Log-type Dini-condition Morrey space
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TillerPET:High-throughput in-situ phenotyping of rice tiller number and compactness from post-harvest stubble
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作者 Letian Zhou Zhixin Tang +7 位作者 Songliang Cao Xiaonan Hu Wei Zhou Xuhui Zhu Xiaodong Bai Hao Lu Fan Chen Weijuan Hu 《The Crop Journal》 2025年第6期1928-1938,共11页
For fast in-situ assessment of tiller phenotypes in rice breeding,we introduce the TillerPET model,an improved transformer-based deep learning solution that permits phenotyping the number and compactness of rice tille... For fast in-situ assessment of tiller phenotypes in rice breeding,we introduce the TillerPET model,an improved transformer-based deep learning solution that permits phenotyping the number and compactness of rice tillers in images of post-harvest rice stubble.A rice tiller phenotype dataset covering three years of field data and four experimental sites across China was constructed to train and validate the model.TillerPET reports an R2 of 0.941 for counting tiller number,demonstrating state-of-the-art performance on the proposed RTP dataset.Beyond its minimal errors in estimating tiller number,TillerPET also achieves an R2 of 0.978 for characterizing tiller compactness.The two phenotypic parameters exhibit a high degree of consistency with expert breeders,offering reliable phenotypic indicators to guide further breeding. 展开更多
关键词 Plant phenotyping Rice tillers Tiller compactness Post-harvest stubble Plant counting
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A Short Note on Compactness in Aligned Spaces and Higgs Spaces 被引量:1
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作者 J. M. S. Sim6es-Pereira 《Journal of Mathematics and System Science》 2017年第6期151-153,共3页
We generalize to aligned spaces and to Higgs spaces the concept of compact topological spaces.
关键词 aligned spaces Higgs spaces compactness.
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GB/T 26656—2023标准解读
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作者 张振威 赵洁 +3 位作者 马裕辰 蒋锐 李雨蕾 朱宇瑾 《理化检验(物理分册)》 2026年第1期34-37,41,共5页
为了更好地理解和执行GB/T 26656—2023标准,针对其主要修订内容进行了详细解读。新标准新增了术语和定义,调整了蠕化率计算公式,修改了颗粒圆整度界限值,统一了组织含量的表示方法,优化了基体组织含量的计算规则,并重新绘制了参照图谱... 为了更好地理解和执行GB/T 26656—2023标准,针对其主要修订内容进行了详细解读。新标准新增了术语和定义,调整了蠕化率计算公式,修改了颗粒圆整度界限值,统一了组织含量的表示方法,优化了基体组织含量的计算规则,并重新绘制了参照图谱,整体具有一定的先进性。 展开更多
关键词 蠕墨铸铁 蠕化率 碳化物 磷共晶 标准修订
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无界区域上带有记忆项的反应扩散方程全局吸引子的存在性
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作者 郑好 张晋 《西北师范大学学报(自然科学版)》 2026年第1期59-66,共8页
证明具有记忆项的反应扩散方程u_(t)-Δu+λu-∫∞k(s)Δu(t-s)d s+f(u)=g,(x,t)∈R^(n)×R^(+)0在无界区域中存在全局吸引子,其中,函数g∈H^(-1)(R^(n)),函数f满足适当的增长性条件.使用非紧性测度方法,证明了该方程在空间L^(2)(R^... 证明具有记忆项的反应扩散方程u_(t)-Δu+λu-∫∞k(s)Δu(t-s)d s+f(u)=g,(x,t)∈R^(n)×R^(+)0在无界区域中存在全局吸引子,其中,函数g∈H^(-1)(R^(n)),函数f满足适当的增长性条件.使用非紧性测度方法,证明了该方程在空间L^(2)(R^(n))×L^(2)_(μ)(R^(+);H^(1)(R^(n)))中存在全局吸引子. 展开更多
关键词 全局吸引子 记忆项 反应扩散方程 无界区域 非紧性测度
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上颌第二前磨牙不同充填方法对牙根抗力影响的三维有限元分析
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作者 张俊杰 格根塔娜 《中国组织工程研究》 北大核心 2026年第14期3515-3523,共9页
背景:既往关于热牙胶及单尖法根管充填的研究主要集中于根管充填的密实度方面,关于牙根抗折性的研究则相对较少。明确牙根在不同充填方法下的应力分布和裂纹特性对提高根管治疗成功率具有重要意义。目的:比较热牙胶垂直加压充填与iRoot... 背景:既往关于热牙胶及单尖法根管充填的研究主要集中于根管充填的密实度方面,关于牙根抗折性的研究则相对较少。明确牙根在不同充填方法下的应力分布和裂纹特性对提高根管治疗成功率具有重要意义。目的:比较热牙胶垂直加压充填与iRoot SP单尖法充填后上颌第二前磨牙牙根的最大抗压载荷强度,同时分析应力集中区域、裂纹特征及牙根整体抗折性能。方法:①收集因正畸减数拔除的废弃上颌第二前磨牙,分别采用热牙胶垂直加压法和iRoot SP单尖法进行根管充填,利用电子万能试验机对牙齿进行垂直加载测试,检测牙根裂纹产生的部位及牙根最大屈服力、最大断裂抗力。②使用锥形束CT扫描获取上颌第二前磨牙原始数据,通过Mimics 21.0和Geomagic 2021软件进行三维重建,运用SolidWorks 2021进行模型组装,分别建立热牙胶垂直加压和iRoot SP单尖根管充填模型,使用ANSYS Workbench软件进行力学分析,分析牙根的最大主应力及应力集中部位。结果与结论:①显微镜观察显示两组牙根均在颊舌向产生裂纹,热牙胶垂直加压充填组牙根最大屈服力为336.4 N,最大断裂抗力为1124.6 N;iRoot SP单尖法充填组牙根最大屈服力为468.8 N、最大断裂抗力为1263.7 N。②有限元分析显示,随着加压力值的不断递增,两组牙根最大主应力值均呈现上升趋势,并且iRoot SP单尖法充填组牙根最大主应力值始终高于热牙胶垂直加压充填组;热牙胶垂直加压充填组牙根应力集中于根管充填物周围,iRoot SP单尖法充填组牙根应力主要分布在牙胶尖周围;在扁根管情况下,牙根应力集中区域及裂纹萌生位置均主要位于颊舌向。三维有限元仿真预测的裂纹萌生位置与体外实验中实际观察的牙根裂纹位置高度一致,证实了有限元模型的有效性。③研究表明,对于上颌第二前磨牙的扁根管,iRoot SP单尖法充填在牙根抗折性和应力分布方面表现出显著优势。 展开更多
关键词 扁根管 单尖法 热牙胶垂直加压技术 根管充填 有限元分析 牙根纵裂
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A NOTE IN APPROXIMATIVE COMPACTNESS AND MIDPOINT LOCALLY K-UNIFORM ROTUNDITY IN BANACH SPACES 被引量:4
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作者 刘春燕 张子厚 周宇 《Acta Mathematica Scientia》 SCIE CSCD 2018年第2期643-650,共8页
In this article, we prove the following results: (1) A Banach space X is weak midpoint locally k-uniformly rotund if and only if every closed ball of X is an approximatively weakly compact k-Chebyshev set; (2) A ... In this article, we prove the following results: (1) A Banach space X is weak midpoint locally k-uniformly rotund if and only if every closed ball of X is an approximatively weakly compact k-Chebyshev set; (2) A Banach space X is midpoint locally k-uniformly rotund if and only if every closed ball of X is an approximatively compact k-Chebyshev set. 展开更多
关键词 k-Chebyshev set approximatively weak compactness approximative compactness weak midpoint locally k-uniform rotundity midpoint locally k-uniform rotundity k-strict rotundity
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Measurement and Spatial Distribution of Urban Agglomeration Industrial Compactness in China 被引量:4
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作者 QI Weifeng FANG Chuanglin SONG Jitao 《Chinese Geographical Science》 SCIE CSCD 2008年第4期291-299,共9页
Urban agglomeration (UA) compactness means spatial concentration degree of physical entities, such as cities (towns), industries, resources, funds, traffic and technologies, whose concentration is formed according to ... Urban agglomeration (UA) compactness means spatial concentration degree of physical entities, such as cities (towns), industries, resources, funds, traffic and technologies, whose concentration is formed according to specified economic and technologic association in the process of UA formation and development. The UA industrial compactness means the concentration degree of industry and industry clusters with reference to the industrial, technologi- cal and economic relations among the cities in the UA in the process of rational industrial division and with the exten- sion of industrial chain. After analyzing the researches on compactness, this paper finds that the relevant measurement coefficient and methods reflecting industrial geographical concentration fail to link industries spatial concentration with urban spatial concentration. Taking 23 UAs as samples and classifying them by development degree, this paper probes into UA compactness and spatial distribution characteristics from the perspective of industry by adopting UA index systems of industry and measurement models. The research finds out: 1) there is obvious positive correlation between UA industrial compactness and UA development degree; 2) the spatial distribution difference of UA industrial compactness is relatively great; and 3) UA industrial compactness shows a gradually decreasing tendency from the eastern part, the middle part to the western part of China. From the research thoughts and approaches, this article suggests that studies on the UA integrated compactness measurement should be enhanced from a multidimensional perspective involving space, traffic, population density and so on. 展开更多
关键词 industrial compactness urban agglomeration(UA) China
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Application of Compactness Detection to Complicated Concrete-Filled Steel Tube by Ultrasonic Method 被引量:3
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作者 杨建江 王飞 +1 位作者 陆苏亮 王川 《Transactions of Tianjin University》 EI CAS 2014年第2期126-132,共7页
An example of using ultrasonic method to detect the compactness of complicated concrete-filled steel tube in certain high-rise building was discussed in this study.Because of the particularity of the complicated concr... An example of using ultrasonic method to detect the compactness of complicated concrete-filled steel tube in certain high-rise building was discussed in this study.Because of the particularity of the complicated concrete-filled steel tubular column,the plane detection method and embedded sounding pipe method were adopted in the process of effectively detecting the column.According to the results of the plane detection method and embedded sounding pipe method,the cementing status of steel tube and concrete can be concluded,which cannot be judged by the hammering method in the rectangular steel tube-reinforced concrete. 展开更多
关键词 ultrasonic method concrete-filled steel tube plane detection method embedded sounding pipe method compactness
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Compactness for the commutators of multilinear singular integral operators with non-smooth kernels 被引量:2
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作者 BU Rui CHEN Jie-cheng 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2019年第1期55-75,共21页
In this paper, the behavior for commutators of a class of bilinear singular integral operators associated with non-smooth kernels on the product of weighted Lebesgue spaces is considered. By some new maximal functions... In this paper, the behavior for commutators of a class of bilinear singular integral operators associated with non-smooth kernels on the product of weighted Lebesgue spaces is considered. By some new maximal functions to control the commutators of bilinear singular integral operators and CMO(Rn) functions, compactness for the commutators is proved. 展开更多
关键词 singular integral OPERATOR maximal function weighted norm inequality COMMUTATOR compact OPERATOR
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Compactness for Commutator of Fractional Integral on Non-homogeneous Morrey Spaces 被引量:2
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作者 Guanghui LU 《Journal of Mathematical Research with Applications》 CSCD 2022年第1期73-88,共16页
The aim of this paper is to establish the necessary and sufficient conditions for the compactness of fractional integral commutator[b,I_(γ)]which is generated by fractional integral I_(γ)and function b∈Lip_(β)(μ)... The aim of this paper is to establish the necessary and sufficient conditions for the compactness of fractional integral commutator[b,I_(γ)]which is generated by fractional integral I_(γ)and function b∈Lip_(β)(μ)on Morrey space over non-homogeneous metric measure space,which satisfies the geometrically doubling and upper doubling conditions in the sense of Hytonen.Under assumption that the dominating functionλsatisfies weak reverse doubling condition,the author proves that the commutator[b,I_(γ)]is compact from Morrey space M_(q)^(p)(μ)into Morrey space M_(t)^(s)(μ)if and only if b∈Lip_(β)(μ). 展开更多
关键词 non-homogeneous metric measure space compactness commutator of fractional integral Lipβ(μ) Morrey space
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Study on mechanical properties of soil-rock mixture of various compactness subjected to freeze-thaw cycles 被引量:2
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作者 Zhong Zhou HaoHui Ding +1 位作者 WenYuan Gao LinRong Xu 《Research in Cold and Arid Regions》 CSCD 2021年第5期450-462,共13页
The soil-rock mixture,a collection of soil particles and rock blocks,is inherently heterogeneous and anisotropic due to significant particle size and material strength differences.This study conducts triaxial tests on... The soil-rock mixture,a collection of soil particles and rock blocks,is inherently heterogeneous and anisotropic due to significant particle size and material strength differences.This study conducts triaxial tests on soil-rock mixture samples of various compactness subjected to varying freeze-thaw cycles.A mesoscopic simulation is carried out by particle flow code(PFC)to analyze the effects of freeze-thaw cycles on the mechanical properties of soil and rock particles.The results show that the mechanical properties of the soil-rock mixture under freeze-thaw cycles are greatly affected by the initial compaction.In general,when the degree of compaction is higher,the influence of freeze-thaw cycles on the soil-rock mixture is greater.The stress-strain curves of the samples with different compactness demonstrate strain-softening behavior.The freeze-thaw cycles greatly influence the failure strength of the samples with a higher degree of compaction but have little impact on the samples with a lower degree of compaction.On the microscopic level,during freeze-thaw cycles,the pore volume in the highly compacted sample is too small to accommodate the volume expansion from ice crystal formation,causing significant strength loss among the soil and rock particles and deterioration of the macroscopic properties of the soil-rock mixture. 展开更多
关键词 soil-rock mixtures freeze-thaw cycle degree of compaction particle flow code
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STRONG COMPACTNESS OF APPROXIMATE SOLUTIONS TO DEGENERATE ELLIPTIC-HYPERBOLIC EQUATIONS WITH DISCONTINUOUS FLUX FUNCTION 被引量:1
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作者 Helge Holden Kenneth H. Karlsen +1 位作者 Darko Mitrovic Evgueni Yu. Panov 《Acta Mathematica Scientia》 SCIE CSCD 2009年第6期1573-1612,共40页
Under a non-degeneracy condition on the nonlinearities we show that sequences of approximate entropy solutions of mixed elliptic-hyperbolic equations are strongly precompact in the general case of a Caratheodory flux ... Under a non-degeneracy condition on the nonlinearities we show that sequences of approximate entropy solutions of mixed elliptic-hyperbolic equations are strongly precompact in the general case of a Caratheodory flux vector. The proofs are based on deriving localization principles for H-measures associated to sequences of measurevalued functions. This main result implies existence of solutions to degenerate parabolic convection-diffusion equations with discontinuous flux. Moreover, it provides a framework in which one can prove convergence of various types of approximate solutions, such as those generated by the vanishing viscosity method and numerical schemes. 展开更多
关键词 degenerate hyperbolic-elliptic equation degenerate convection-diffusion equation conservation law discontinuous flux approximate solutions compactness
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电驱式自激振动深松减阻单体的设计与试验
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作者 张晓伟 赵举文 +1 位作者 张印生 胡科全 《农机化研究》 北大核心 2026年第1期72-78,共7页
为解决目前深松作业机具耕作阻力大、耕作质量低、能耗高的问题,基于电驱式振动减阻原理设计研制了电驱式自激振动深松减阻单体。对电驱式自激振动深松减阻装置和浮动镇压碎土装置进行优化设计,铲柄采用垂直双翼形结构,铲柄上部末端设... 为解决目前深松作业机具耕作阻力大、耕作质量低、能耗高的问题,基于电驱式振动减阻原理设计研制了电驱式自激振动深松减阻单体。对电驱式自激振动深松减阻装置和浮动镇压碎土装置进行优化设计,铲柄采用垂直双翼形结构,铲柄上部末端设有铰接连接孔,下端设有翼板连接孔,并安装有张角为65°的翼铲,深松铲入土角为23.8°,并进行了田间试验。利用Design-Expert 10.0软件对响应曲面模型展开多因素交互作用分析,选取振动频率、振动振幅、深松深度为影响因素,以牵引阻力为评价指标,优化后得到最佳组合参数:振动频率8 Hz、振动振幅25 mm、深松深度400 mm,此时振动模式下,牵引阻力为13.56 kN,牵引阻力平均降幅为15.56%,减阻效果明显。整机性能可靠,满足深松机评定指标,可为振动深松机特性分析与性能参数优化提供参考。 展开更多
关键词 自激振动 减阻 电驱 浮动镇压碎土 性能参数 响应分析
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ON COMPACTNESS FOR ITERATED COMMUTATORS 被引量:1
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作者 刘永民 于燕燕 《Acta Mathematica Scientia》 SCIE CSCD 2011年第2期491-500,共10页
The authors study the iterated commutators on the weighted Bergman spaces A2(φ), and prove that Cnh is compact on A2(φ) if and only if h ∈ B0.
关键词 Weighted Bergman space iterated commutator normal function littleBloch function compactness
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COMPACTNESS FOR THE COMMUTATOR OF BOCHNER-RIESZ OPERATOR 被引量:1
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作者 卜瑞 陈杰诚 胡国恩 《Acta Mathematica Scientia》 SCIE CSCD 2017年第5期1373-1384,共12页
Let α ∈0,(n-1)/2 and T~α be the Bochner-Riesz operator of order α. In this paper, for n = 2 and n ≥ 3, the compactness on Lebesgue spaces and Morrey spaces are considered for the commutator of Bochner-Riesz opera... Let α ∈0,(n-1)/2 and T~α be the Bochner-Riesz operator of order α. In this paper, for n = 2 and n ≥ 3, the compactness on Lebesgue spaces and Morrey spaces are considered for the commutator of Bochner-Riesz operator generated by CMO(R^n) function and T~α. 展开更多
关键词 Bochner-Riesz operator COMMUTATOR compact operator Fourier transform estimate
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EQUI-ATTRACTION AND BACKWARD COMPACTNESS OF PULLBACK ATTRACTORS FOR POINT-DISSIPATIVE GINZBURG-LANDAU EQUATIONS 被引量:1
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作者 李扬荣 佘连兵 尹金艳 《Acta Mathematica Scientia》 SCIE CSCD 2018年第2期591-609,共19页
A new concept of an equi-attractor is introduced, and defined by the minimal compact set that attracts bounded sets uniformly in the past, for a non-autonomous dynam- ical system. It is shown that the compact equi-att... A new concept of an equi-attractor is introduced, and defined by the minimal compact set that attracts bounded sets uniformly in the past, for a non-autonomous dynam- ical system. It is shown that the compact equi-attraction implies the backward compactness of a pullback attractor. Also, an eventually equi-continuous and strongly bounded process has an equi-attractor if and only if it is strongly point dissipative and strongly asymptotically compact. Those results primely strengthen the known existence result of a backward bounded pullback attractor in the literature. Finally, the theoretical criteria are applied to prove the existence of both equi-attractor and backward compact attractor for a Ginzburg-Landau equation with some varying coefficients and a backward tempered external force. 展开更多
关键词 Non-autonomous systems point dissipative processes pullback attractors backward compact attractors equi-attractors Ginzburg-Landau equations
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THE COMPACTNESS OF A KIND OF GENERALIZED HANKEL OPERATORS ON THE BERGMAN SPACE OF THE UNIT BALL 被引量:1
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作者 罗罗 史济怀 《Acta Mathematica Scientia》 SCIE CSCD 2000年第4期471-475,共5页
This paper gives the compactness criteria for a kind of generalized Hankel operators on Bergman spaces Lpa(B) defined by M. M. Peloso.
关键词 Hankel operator compactness Bergman spa?
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紧凑城市背景下日本中小城市土地区划整理的经验与启示
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作者 阴博文 《华中建筑》 2026年第1期29-32,共4页
该文探讨了日本土地区划整理的原理与类型,并分析了中小城市中住宅用地格局调整和市区公共设施布局优化的实践。通过鹿儿岛市和山形县鹤冈市的案例研究发现,小规模且精细的土地区划整理能够有效改变住宅用地的区块形状并更新或改造公共... 该文探讨了日本土地区划整理的原理与类型,并分析了中小城市中住宅用地格局调整和市区公共设施布局优化的实践。通过鹿儿岛市和山形县鹤冈市的案例研究发现,小规模且精细的土地区划整理能够有效改变住宅用地的区块形状并更新或改造公共设施。鹿儿岛市通过土地整理和基础设施现代化增强了市中心的商业功能;而鹤冈市则通过整合低效用地和空置住宅,促进了经济和人口的再聚集。该文提出中国的中小城市应采用灵活多样的土地区划整理方法,并引入多元化的城市建设参与者,运用求同存异的城市更新策略,以应对城市发展中的多元化挑战,推动城市的可持续发展。 展开更多
关键词 紧凑城市 土地区划整理 中小城市 鹿儿岛市 鹤冈市
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Compactness of Composition Operators from the p-Bloch Space to the q-Bloch Space on the Classical Bounded Symmetric Domains 被引量:1
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作者 Jianbing Su Huijuan Li +1 位作者 Xingxing Miao Rui Wang 《Advances in Pure Mathematics》 2014年第12期649-664,共16页
In this paper, we introduce the weighted Bloch spaces on the first type of classical bounded symmetric domains , and prove the equivalence of the norms and . Furthermore, we study the compactness of composition operat... In this paper, we introduce the weighted Bloch spaces on the first type of classical bounded symmetric domains , and prove the equivalence of the norms and . Furthermore, we study the compactness of composition operator from to , and obtain a sufficient and necessary condition for to be compact. 展开更多
关键词 BLOCH Space Classical Bounded Symmetric DOMAINS Composition Operators compactness BERGMAN Metric
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