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A SPECIAL MODULUS OF CONTINUITY AND THE K-FUNCTIONAL
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作者 Nadezhda DOLMATOVA 《Acta Mathematica Scientia》 SCIE CSCD 2016年第5期1531-1540,共10页
We consider the questions connected with the approximation of a real continuous 1-periodic functions and give a new proof of the equivalence of the special Boman-Shapiro modulus of continuity with Peetre’s K-function... We consider the questions connected with the approximation of a real continuous 1-periodic functions and give a new proof of the equivalence of the special Boman-Shapiro modulus of continuity with Peetre’s K-functional. We also prove Jackson’s inequality for the approximation by trigonometric polynomials. 展开更多
关键词 modulus of continuity K-FUNCTIONAL Jackson's theorem
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QUASI-MODULUS OF CONTINUITY AND BEST APPROXIMATIONS
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作者 Qiu Shuxi(Dept. of Math., Xiamen Univ.Xiamen 361005) 《数学研究》 CSCD 1994年第1期154-157,共4页
QUASI-MODULUSOFCONTINUITYANDBESTAPPROXIMATIONS¥QiuShuxi(Dept.ofMath.,XiamenUniv.Xiamen361005)Abstract:Inthis... QUASI-MODULUSOFCONTINUITYANDBESTAPPROXIMATIONS¥QiuShuxi(Dept.ofMath.,XiamenUniv.Xiamen361005)Abstract:Inthispaperaconceptofth... 展开更多
关键词 准系数连续 最佳逼近 唯一循环 哈迪空间
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Nonautonomous solitons in the continuous wave background of the variable-coefficient higher-order nonlinear Schrodinger equation
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作者 戴朝卿 陈未路 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第1期143-146,共4页
We reduce the variable-coefficient higher-order nonlinear Schrodinger equation (VCHNLSE) into the constantcoefficient (CC) one. Based on the reduction transformation and solutions of CCHNLSE, we obtain analytical ... We reduce the variable-coefficient higher-order nonlinear Schrodinger equation (VCHNLSE) into the constantcoefficient (CC) one. Based on the reduction transformation and solutions of CCHNLSE, we obtain analytical soliton solutions embedded in the continuous wave background for the VCHNLSE. Then the excitation in advancement and sustainment of soliton arrays, and postponed disappearance and sustainment of the bright soliton embedded in the background are discussed in an exponential system. 展开更多
关键词 higher-order nonlinear Schrodinger equation soliton solution continuous wave background postponed disappearance and sustainment of soliton
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On Wavelet Transform General Modulus Maxima Metric for Singularity Classification in Mammograms
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作者 Tomislav Bujanovic Ikhlas Abdel-Qader 《Open Journal of Medical Imaging》 2013年第1期17-30,共14页
Continuous wavelet transform is employed to detect singularities in 2-D signals by tracking modulus maxima along maxima lines and particularly applied to microcalcification detection in mammograms. The microcalcificat... Continuous wavelet transform is employed to detect singularities in 2-D signals by tracking modulus maxima along maxima lines and particularly applied to microcalcification detection in mammograms. The microcalcifications are modeled as smoothed positive impulse functions. Other target property detection can be performed by adjusting its mathematical model. In this application, the general modulus maximum and its scale of each singular point are detected and statistically analyzed locally in its neighborhood. The diagnosed microcalcification cluster results are compared with health tissue results, showing that general modulus maxima can serve as a suspicious spot detection tool with the detection performance no significantly sensitive to the breast tissue background properties. Performed fractal analysis of selected singularities supports the statistical findings. It is important to select the suitable computation parameters-thresholds of magnitude, argument and frequency range-in accordance to mathematical description of the target property as well as spatial and numerical resolution of the analyzed signal. The tests are performed on a set of images with empirically selected parameters for 200 μm/pixel spatial and 8 bits/pixel numerical resolution, appropriate for detection of the suspicious spots in a mammogram. The results show that the magnitude of a singularity general maximum can play a significant role in the detection of microcalcification, while zooming into a cluster in image finer spatial resolution both magnitude of general maximum and the spatial distribution of the selected set of singularities may lead to the breast abnormality characterization. 展开更多
关键词 continuous Wavelet Transform Fractal Dimension GENERAL modulus Maximum MICROCALCIFICATION SINGULARITY Smoothed IMPULSE Function
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Exact Convergence Rates of Functional Modulus of Continuity of a Wiener Process
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作者 王文胜 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2002年第4期507-514,共8页
Let {W(t),t > 0} be a standard Wiener process and S be the set of Strassen's functions. In this paper we investigate the exact rates of convergence to zero of the variables supp<t<1-h inff∈s sup0<x<... Let {W(t),t > 0} be a standard Wiener process and S be the set of Strassen's functions. In this paper we investigate the exact rates of convergence to zero of the variables supp<t<1-h inff∈s sup0<x<1 |(W(t + hx) - W(t))(2hlogh-1)-1/2 - f(x)| and inf0<t<1-h sup0<x<1|(W(t + hx) -W(t))(2hlogh-1)-1/2 - f(x)| for any f ∈ S. As a consequence, a relation between the modulus of non-differentiability and the functional modulus of continuity for a Wiener process is established. 展开更多
关键词 Wiener process functional modulus of continuity modulus of non-differentiability
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FUNCTIONAL MODULUS OF CONTINUITY FOR BROWNIAN MOTION IN HLDER NORM 被引量:10
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作者 WEI QICAI School of Economics, Zhejiang University, Hangzhou 310028, China. 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2001年第2期223-232,共10页
The author establishes a large deviation for k-dimensional Brownian motion B in stronger topology, by which the functional modulus of continuity for B in Holder norm can be obtained.
关键词 Large deviations Functional modulus of continuity k-dimensional Brownian motion Holder norm
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Local Continuity Modulus for Wiener and Infinite Dimensional OU Processes 被引量:3
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作者 Lu Chuanrong Shen Siwei Wang Xiuyun Department of Mathematics Hangzhou University Hangzhou, 310028 China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 1994年第2期219-224,共6页
In this paper, we gave a proof for the local continuity modulus theorem of the Wiener process, i. e., lim t→0 sup 0≤s≤t |W(s)|/(2s log log(1/s))<sup>1/2</sup>=1 a.s. This result was given by Csrg... In this paper, we gave a proof for the local continuity modulus theorem of the Wiener process, i. e., lim t→0 sup 0≤s≤t |W(s)|/(2s log log(1/s))<sup>1/2</sup>=1 a.s. This result was given by Csrg and Revesz (1981), but the proof gets them nowhere. We also gave a similar local continuity modulus result for the infinite dimensional OU processes. 展开更多
关键词 In OU Local continuity modulus for Wiener and Infinite Dimensional OU Processes
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一类Stancu型的Szász-Mirakjan-Durrmeyer算子的逼近性质研究
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作者 连博勇 蔡清波 《高校应用数学学报(A辑)》 北大核心 2024年第2期211-217,共7页
该文介绍了一类Stancu型的Szász-Mirakjan-Durrmeyer算子,计算了该算子的一阶到四阶矩.然后用连续模和K-泛函等工具,讨论了该算子的逼近性质,还研究了算子对Lipschitz函数类的估计.最后建立了该算子的Voronvskaya型渐近展开式.所... 该文介绍了一类Stancu型的Szász-Mirakjan-Durrmeyer算子,计算了该算子的一阶到四阶矩.然后用连续模和K-泛函等工具,讨论了该算子的逼近性质,还研究了算子对Lipschitz函数类的估计.最后建立了该算子的Voronvskaya型渐近展开式.所得定理扩展了Aslan(2022)的结果. 展开更多
关键词 Szász-Mirakjan-Durrmeyer算子 K-泛函 连续模 Voronvskaya型渐近展开公式
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振动轮两侧加速度差异及连续压实指标优化研究
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作者 赵辉 刘泽潮 +2 位作者 冯怀平 常建梅 马德良 《铁道学报》 EI CAS CSCD 北大核心 2024年第3期120-128,共9页
连续压实控制技术主要通过振动轮单侧振动响应描述土体压实状态,已在工程中得到广泛应用。然而,研究发现压实过程中存在振动轮两侧加速度响应不一致的现象,这可能导致现有测试方法在相同位置出现不同的刚度测试结果,因此研究振动轮两侧... 连续压实控制技术主要通过振动轮单侧振动响应描述土体压实状态,已在工程中得到广泛应用。然而,研究发现压实过程中存在振动轮两侧加速度响应不一致的现象,这可能导致现有测试方法在相同位置出现不同的刚度测试结果,因此研究振动轮两侧振动差异性对提高连续压实测试精度具有重要意义。结合现场试验,采集压路机振动轮两侧的加速度信号,重点分析了不同压实遍数、振动频率下两侧加速度峰值、倍频幅值的变化与分布规律;以双侧响应为基础提出平均指标,通过相关性分析对指标适用性进行验证。研究结果表明:随着压实遍数的增加,两侧加速度峰值差异逐渐减小,经4遍压实后差异由24.4%降至13.3%;振动轮结构偏心会造成振动轮两侧加速度频谱中基频幅值差异的产生,被压土体两侧刚度不均会造成2倍频、3倍频幅值差异的产生;双侧平均指标μAICV与动态变形模量的相关性为0.75,表明双侧平均指标μAICV可用于路基压实质量控制,相比单侧连续压实控制指标,可有效提高现场质量控制精度。 展开更多
关键词 连续压实控制 响应差异 振动轮结构 动态变形模量 控制精度 双侧平均指标
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改造的Catmull-Rom插值基函数及其逼近性质
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作者 刘星 章仁江 《高校应用数学学报(A辑)》 北大核心 2024年第4期391-403,共13页
此文利用多项式再生性和局部支撑性对著名的Catmull-Rom插值基函数进行改造,获得新的插值基函数,生成新的插值算子,并求得新插值算子精确的Lebesgue常数,估计了其逼近连续函数的收敛速度,理论和数值例子都表明新插值算子的逼近效果优于... 此文利用多项式再生性和局部支撑性对著名的Catmull-Rom插值基函数进行改造,获得新的插值基函数,生成新的插值算子,并求得新插值算子精确的Lebesgue常数,估计了其逼近连续函数的收敛速度,理论和数值例子都表明新插值算子的逼近效果优于其他各类插值算子. 展开更多
关键词 插值 连续模 逼近误差 LEBESGUE常数 基函数
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W^(m,p(t,x))-Estimate for a Class of Higher-Order Parabolic Equations with Partially BMO Coefficients
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作者 TIAN Hong HAO Shuai ZHENG Shenzhou 《Journal of Partial Differential Equations》 CSCD 2024年第2期198-234,共37页
We prove a global estimate in the Sobolev spaces with variable exponents to the solution of a class of higher-order divergence parabolic equations with measurable coefficients over the non-smooth domains.Here,it is ma... We prove a global estimate in the Sobolev spaces with variable exponents to the solution of a class of higher-order divergence parabolic equations with measurable coefficients over the non-smooth domains.Here,it is mainly assumed that the coefficients are allowed to be merely measurable in one of the spatial variables and have a small BMO quasi-norm in the other variables at a sufficiently small scale,while the boundary of the underlying domain belongs to the so-called Reifenberg flatness.This is a natural outgrowth of Dong-Kim-Zhang’s papers[1,2]from the W^(m,p)-regularity to the W^(m,p(t,x))-regularity for such higher-order parabolic equations with merely measurable coefficients with Reifenberg flat domain which is beyond the Lipschitz domain with small Lipschitz constant. 展开更多
关键词 A higher-order parabolic equation Sobolev spaces with variable exponents partially BMO quasi-norm Reifenberg flat domains log-Hölder continuity
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基于连续检测的高速铁路路基压实质量控制方法 被引量:1
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作者 安再展 蔡德钩 +3 位作者 叶阳升 朱宏伟 郑新国 李斯 《铁道建筑》 北大核心 2024年第2期13-19,共7页
针对传统检测方法无法满足路基压实质量实时、全面控制要求的问题,开展了高速铁路路基碾压足尺模型连续检测试验,分析了路基压实过程中振动轮振动能量变化规律,建立了能量压实值与动态变形模量、地基系数和压实度的相关关系,对基于连续... 针对传统检测方法无法满足路基压实质量实时、全面控制要求的问题,开展了高速铁路路基碾压足尺模型连续检测试验,分析了路基压实过程中振动轮振动能量变化规律,建立了能量压实值与动态变形模量、地基系数和压实度的相关关系,对基于连续检测的路基压实程度、压实稳定性和压实均匀性进行分析。结果表明:振动轮振动能量随碾压遍数增大而增大,能量压实值与常规检测指标具有强相关性,可以作为高速铁路路基压实质量连续检测指标;采用考虑90%置信水平预测区间下限的压实质量连续控制值判断路基压实程度更符合路基实际压实状态;碾压区域内能量压实值平均增长率应小于2%,出现过压现象时应停止碾压;碾压结束后,各检测单元能量压实值应在碾压区域平均能量压实值的80%~120%范围内。 展开更多
关键词 高速铁路路基 压实质量 连续检测 控制方法 能量压实值 动态变形模量 地基系数
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汽车空调安装卡扣模具设计
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作者 马朝平 李亚玲 +1 位作者 陈亚茹 湛强 《内燃机与配件》 2024年第14期38-40,共3页
分析了汽车空调安装卡扣的结构与冲压成形工艺,制定了冲压模具的工艺方案,阐述了排样设计方法与连续模的结构设计以及凸、凹模等关键模具零件的加工工艺,同时阐述了模具的工作过程,可为类似的汽车空调安装卡扣模具设计提供参考。
关键词 汽车空调安装卡扣 排样 连续模 工作过程
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Experimental and Theoretical Analyses on the Density and Modulus Development of Concrete Under Continued Hydration
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作者 Lanzhen Yu Jiankang Chen Hui Song 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2018年第2期161-173,共13页
In this paper, new models of the density and modulus development of concrete under continued hydration were studied. Experimental study was performed for different mixes of concrete. To avoid considering the effect of... In this paper, new models of the density and modulus development of concrete under continued hydration were studied. Experimental study was performed for different mixes of concrete. To avoid considering the effect of variation of Poisson's ratio, the one-dimensional ultrasonic technique was adopted to detect the modulus development of concrete under continued hydration. The experimental results indicate the nonlinear characteristics of density and modulus evolution. At the initial stage of continued hydration, the density and modulus increase quickly, and then the increases slow down and finally tend to be constant. The mechanism of modulus enhancement is that the newly produced C-S-H gel in the continued hydration process not only leads to the decrease in porosity, but also repairs the initial defects of concrete. Based on this mechanism, simple differential equations for the density and modulus development of concrete were established by considering the chemical reactions of continued hydration, and new simple models for density and modulus development were proposed. 展开更多
关键词 CONCRETE continued hydration Density development modulus development Ultrasonic
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ON THE LEAST DOMINANT CONTINUOUS MODULUS AND ITS APPLICATION
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作者 CHENTIANPIN ZHUWENGE 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1996年第1期73-80,共8页
This paper discusses pointwise error estimates for the approximation by bounded linear operators of coatinuous functions defined on compact meric spaces (X, d). The authors introduce a new majorant of the modulus of t... This paper discusses pointwise error estimates for the approximation by bounded linear operators of coatinuous functions defined on compact meric spaces (X, d). The authors introduce a new majorant of the modulus of the coutinuity which is the smallest among those g(ξ)’s which have the following peoperties ω(f, ξ)≤g(f,ε) and g(f, λε)≤ (1 + λ)g(f,ε) and by tthe majorant a new quatitative Korovkin type theorem on any compact metric space is proved. 展开更多
关键词 Quantitative approximation modulus of the continuity Compact metric space
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Site Characterization Index for Continuous Power Quality Monitoring Based on Higher-order Statistics
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作者 Olivia Florencias-Oliveros Juan-José González-de-la-Rosa +3 位作者 Jose-María Sierra-Fernández Agustín Agüera-Pérez Manuel-Jesús Espinosa-Gavira José-Carlos Palomares-Salas 《Journal of Modern Power Systems and Clean Energy》 SCIE EI CSCD 2022年第1期222-231,共10页
The high penetration of distributed generation(DG)has set up a challenge for energy management and consequently for the monitoring and assessment of power quality(PQ).Besides,there are new types of disturbances owing ... The high penetration of distributed generation(DG)has set up a challenge for energy management and consequently for the monitoring and assessment of power quality(PQ).Besides,there are new types of disturbances owing to the uncontrolled connections of non-linear loads.The stochastic behaviour triggers the need for new holistic indicators which also deal with big data of PQ in terms of compression and scalability so as to extract the useful information regarding different network states and the prevailing PQ disturbances for future risk assessment and energy management systems.Permanent and continuous monitoring would guarantee the report to claim for damages and to assess the risk of PQ distortions.In this context,we propose a measurement method that postulates the use of two-dimensional(2D)diagrams based on higher-order statistics(HOSs)and a previous voltage quality index that assesses the voltage supply waveform in a continous monitoring campaign.Being suitable for both PQ and reliability applications,the results conclude that the inclusion of HOS measurements in the industrial metrological reports helps characterize the deviations of the voltage supply waveform,extracting the individual customers’pattern fingerprint,and compressing the data from both time and spatial aspects.The method allows a continuous and robust performance needed in the SG framework.Consequently,the method can be used by an average consumer as a probabilistic method to assess the risk of PQ deviations in site characterization. 展开更多
关键词 continuous statistical monitoring big data data compression higher-order statistics(HOSs) power quality(PQ)
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输电线路单端行波故障测距新算法 被引量:40
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作者 高洪雨 陈青 +2 位作者 徐丙垠 王磊 宋卫平 《电力系统自动化》 EI CSCD 北大核心 2017年第5期121-127,共7页
输电线路发生故障后,行波从故障点出发向不同方向行进,基于单端行波测距原理,故障点反射波以及其他折射反射行波到达检测母线的各个行波波头极性组合,反映了线路的不同故障区段,可以直接判断出故障点所属区段。文中对随机故障发生的4个... 输电线路发生故障后,行波从故障点出发向不同方向行进,基于单端行波测距原理,故障点反射波以及其他折射反射行波到达检测母线的各个行波波头极性组合,反映了线路的不同故障区段,可以直接判断出故障点所属区段。文中对随机故障发生的4个区段,利用各类行波到达检测母线的时间,分别推导了不受行波速度影响的故障测距算法。现场应用验证了该算法的有效性。 展开更多
关键词 输电线路 行波测距 行波波头 连续小波变换 模极大值
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结构裂缝损伤识别的连续小波分析方法 被引量:12
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作者 滕海文 许树峰 +1 位作者 李秀芬 霍达 《振动与冲击》 EI CSCD 北大核心 2008年第8期155-157,共3页
应变模态是对结构局部特征变化比较敏感的参数,以应变模态作为响应信号,利用小波变换在时域和频域都具有的强局部化性质、易提取信号奇异部分的特点,采用连续小波进行裂缝损伤定位及定量化研究,建立了模极大值与裂缝位置、李氏指数与损... 应变模态是对结构局部特征变化比较敏感的参数,以应变模态作为响应信号,利用小波变换在时域和频域都具有的强局部化性质、易提取信号奇异部分的特点,采用连续小波进行裂缝损伤定位及定量化研究,建立了模极大值与裂缝位置、李氏指数与损伤程度之间的关系,解决了仅从应变模态数值的变化不能完全反映结构损伤程度的问题。数值模拟表明,连续小波分析的损伤识别方法不仅实现精确损伤定位,而且小波变换的李氏指数能较好的表征损伤程度,无论单处裂缝损伤还是多处裂缝损伤李氏指数均随着裂缝深度的增大而减小。 展开更多
关键词 结构裂缝识别 连续小波分析 模极大值 李氏指数
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预应力混凝土连续梁桥动力特性及影响因素分析 被引量:8
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作者 任翔 谭潇 +2 位作者 宋飞 齐海鹏 马敏 《重庆交通大学学报(自然科学版)》 CAS 北大核心 2018年第10期8-12,共5页
为了探明新建桥梁动载试验实测一阶频率与理论计算结果产生偏差的原因,以某预应力混凝土变截面连续梁成桥动载试验为背景,实测了在脉动荷载下桥梁的一阶频率和振型,建立了有限元模型,同时计算了桥梁一阶频率的理论值,并对二者进行了对比... 为了探明新建桥梁动载试验实测一阶频率与理论计算结果产生偏差的原因,以某预应力混凝土变截面连续梁成桥动载试验为背景,实测了在脉动荷载下桥梁的一阶频率和振型,建立了有限元模型,同时计算了桥梁一阶频率的理论值,并对二者进行了对比;分析了纵向普通钢筋、预应力钢筋、护栏、混凝土动弹性模量等4个因素对桥梁动力特性的影响。结果表明:一阶频率实测值为1.760 Hz,理论计算值为1.395 Hz,二者偏差约21%;在有限元模型中计入纵向普通钢筋、预应力钢筋、护栏和混凝土动弹性模量后,结构的一阶频率分别为1.416、1.413、1.384和1.634 Hz,综合考虑4个因素的一阶频率为1.684 Hz;4个因素中,混凝土动弹性模量对结构一阶频率影响最为显著,其它因素影响较小可不考虑。建议利用桥梁基频进行结构刚度评定时,应在有限元模型中计入混凝土动弹性模量,使其更为接近实际状态。 展开更多
关键词 桥梁工程 连续梁桥 动载试验 动弹性模量
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一类混合型算子的点态逼近结果 被引量:3
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作者 郭顺生 张更生 杜同凯 《西南师范大学学报(自然科学版)》 CAS CSCD 北大核心 2003年第3期352-357,共6页
将连续模ω2φλ(f,t)应用到一类混合型算子上,得到了其点态逼近结果的正逆定理.
关键词 混合型算子 点态逼近 连续模 算子逼近 正定理 逆定理
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