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Mellin Transform-Based Correction Method for Linear Scale Inconsistency of Intrusion Events Identification in OFPS
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作者 Baocheng WANG Dandan QU +1 位作者 Qing TIAN Liping PANG 《Photonic Sensors》 SCIE EI CAS CSCD 2018年第3期220-227,共8页
为在光纤维警告前系统(OFPS ) 的侵入信号的线性规模是不一致的问题,这篇论文论述一个方法改正规模。第一,侵入信号被拦截,并且有相等的长度的片断的一个总数被获得。然后, Mellin 变换(MT ) 被使用把他们变换成一样的规模。光谱特... 为在光纤维警告前系统(OFPS ) 的侵入信号的线性规模是不一致的问题,这篇论文论述一个方法改正规模。第一,侵入信号被拦截,并且有相等的长度的片断的一个总数被获得。然后, Mellin 变换(MT ) 被使用把他们变换成一样的规模。光谱特征被 Fourier 变换获得。最后,我们采用识别侵入的神经网络打的背繁殖(BP ) ,它拿光谱是的特征输入。我们执行了地实验并且收集了包含拣的信号的光纤维侵入信号,铲信号,并且运用信号。试验性的结果证明建议算法罐头有效地改进侵入信号的识别精确性。 展开更多
关键词 侵入 修正方法 线性 FOURIER 鉴定 事件 光谱特征 神经网络
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High-efciency improved symmetric successive over-relaxation preconditioned conjugate gradient method for solving large-scale finite element linear equations 被引量:1
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作者 李根 唐春安 李连崇 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2013年第10期1225-1236,共12页
Fast solving large-scale linear equations in the finite element analysis is a classical subject in computational mechanics. It is a key technique in computer aided engineering (CAE) and computer aided manufacturing ... Fast solving large-scale linear equations in the finite element analysis is a classical subject in computational mechanics. It is a key technique in computer aided engineering (CAE) and computer aided manufacturing (CAM). This paper presents a high-efficiency improved symmetric successive over-relaxation (ISSOR) preconditioned conjugate gradient (PCG) method, which maintains lelism consistent with the original form. Ideally, the by 50% as compared with the original algorithm. the convergence and inherent paralcomputation can It is suitable for be reduced nearly high-performance computing with its inherent basic high-efficiency operations. By comparing with the numerical results, it is shown that the proposed method has the best performance. 展开更多
关键词 improved preconditioned conjugate gradient (PCG) method conjugate gradient method large-scale linear equation finite element method
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A Modification of the Relative Weightings of Symptoms Utilizing a Logistic Function to Enhance the Linearity of the Brief Psychiatric Rating Scale: A Retrospective Analysis
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作者 Jitsuki Sawamura Shigeru Morishita Jun Ishigooka 《Journal of Behavioral and Brain Science》 2012年第2期225-238,共14页
Introduction: Although the Brief Psychiatric Rating Scale (BPRS) is widely used for evaluating patients with schizophrenia, the meaning of the weights of the individual symptoms is ambiguous. The aims of the study wer... Introduction: Although the Brief Psychiatric Rating Scale (BPRS) is widely used for evaluating patients with schizophrenia, the meaning of the weights of the individual symptoms is ambiguous. The aims of the study were 1) to investigate whether the modification of relative weights of items of the BPRS is able to enhance its correlation with the Clinical Global Impression-Schizophrenia scale (CGI-SCH) and 2) to construct a potential modified BPRS. Methods: We evaluated 200 schizophrenia patients using the BPRS and the CGI-SCH and drew the scatter plot distributions of the two scales. Next, univariate regression for the CGI-SCH using individual symptoms of the BPRS was performed. Multivariate regression utilizing the ‘logistic function’ was then conducted to allocate marks to each item and Pearson’s r correlation coefficient and r-squared between the two scales were assessed. After that, we constructed an example of a potential modified BPRS. Results: With the scatter plot for the two scales, a logarithmic curve was obtained;this was described by [CGI-SCH] = 3.2248 × ln[18-item BPRS] – 7.2044 (p i” that could express the relative weights of individual symptoms. Subsequently, modification of point allocations according to “Pi” yielded a Pearson’s r of 0.8491 and an r-squared of 0.7718 (not changed) (both p < 0.001). An example of a potential modified BPRS was constructed. Conclusions: Within the limits of our data, the weightings of items of the BPRS improved the correlation of the BPRS with the CGI-SCH for evaluating schizophrenia. 展开更多
关键词 Evaluation scale linearITY Weightings MODIFICATION BPRS SCHIZOPHRENIA
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DECENTRALIZED STABILIZATION OF LARGE-SCALE LINEAR INTERCONNECTED SYSTEMS WITH TIME-VARYING DELAYS
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作者 余昭旭 孙继涛 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2000年第9期1053-1057,共5页
The decentralized stabilization conditions for large-scale linear interconnection systems with time-varying delays were established by using some different decomposition cases of interconnection matrices, and a method... The decentralized stabilization conditions for large-scale linear interconnection systems with time-varying delays were established by using some different decomposition cases of interconnection matrices, and a method for designing the decentralized local memoryless state feedback controllers was proposed. All of the considered delays are continuous function, and satisfy some conditions. 展开更多
关键词 large-scale systems linear interconnection systems time-varying delay decentralized stabilization
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Combining Methods of Lyapunov for Exponential Stability of Linear Dynamic Systems on Time Scales
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作者 Nguyen Ngoc Huy Dang Dinh Chau 《Applied Mathematics》 2014年第21期3452-3459,共8页
Consider the linear dynamic equation on time scales (1) where , ,?is a rd-continuous function, T is a time scales. In this paper, we shall investigate some results for the exponential stability of the dynamic Equation... Consider the linear dynamic equation on time scales (1) where , ,?is a rd-continuous function, T is a time scales. In this paper, we shall investigate some results for the exponential stability of the dynamic Equation (1) by combinating the first approximate method and the second method of Lyapunov. 展开更多
关键词 Time scales EXPONENTIAL Stability linear Dynamic EQUATION
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Analysis of the Invariance and Generalizability of Multiple Linear Regression Model Results Obtained from Maslach Burnout Scale through Jackknife Method
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作者 Tolga Zaman Kamil Alakus 《Open Journal of Statistics》 2015年第7期645-651,共7页
The purpose of this study was to examine the burnout levels of research assistants in Ondokuz Mayis University and to examine the results of multiple linear regression model based on the results obtained from Maslach ... The purpose of this study was to examine the burnout levels of research assistants in Ondokuz Mayis University and to examine the results of multiple linear regression model based on the results obtained from Maslach Burnout Scale with Jackknife Method in terms of validity and generalizability. To do this, a questionnaire was given to 11 research assistants working at Ondokuz Mayis University and the burnout scores of this questionnaire were taken as the dependent variable of the multiple linear regression model. The variable of burnout was explained with the variables of age, weekly hours of classes taught, monthly average credit card debt, numbers of published articles and reports, gender, marital status, number of children and the departments of the research assistants. Dummy variables were assigned to the variables of gender, marital status, number of children and the departments of the research assistants and thus, they were made quantitative. The significance of the model as a result of multiple linear regressions was examined through backward elimination method. After this, for the five explanatory variables which influenced the variable of burnout, standardized model coefficients and coefficients of determination, and 95% confidence intervals of these values were estimated through Jackknife Method and the generalizability of the parameter estimation results of these variables on population was researched. 展开更多
关键词 JACKKNIFE METHOD INVARIANCE GENERALIZABILITY Maslach BURNOUT scale Multiple linear Regression Backward Elimination METHOD
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Robust non-fragile control for discrete-delay nonlinear large-scale systems
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作者 吴忠强 李卓 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2010年第4期481-485,共5页
Time-delays,due to the information transmission between subsystems,naturally exist in large-scale systems and the existence of the delay is frequently a source of instability. This paper considers the problems of robu... Time-delays,due to the information transmission between subsystems,naturally exist in large-scale systems and the existence of the delay is frequently a source of instability. This paper considers the problems of robust non-fragile fuzzy control for a class of uncertain discrete nonlinear large-scale systems with time-delay and controller gain perturbations described by T-S fuzzy model. An equivalent T-S fuzzy model is represented for discrete-delay nonlinear large-scale systems. A sufficient condition for the existence of such non-fragile controllers is further derived via the Lyapunov function and the linear matrix inequality( LMI) approach. Simulation results demonstrate the feasibility and the effectiveness of the proposed design and the proper stabilization of the system in spite of controller gain variations and uncertainties. 展开更多
关键词 non-fragile control discrete-delay nonlinear large-scale systems T-S fuzzy model linear matrix inequality
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林分和景观水平因子对松材线虫病发生的影响——以山东威海地区松林为例
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作者 李好男 俞琳锋 +3 位作者 詹钟易 迟世宽 任利利 骆有庆 《环境昆虫学报》 CSCD 北大核心 2024年第3期616-624,共9页
松材线虫病(Pine wilt disease)传入我国以来,造成了大面积松林枯死,严重威胁我国的林业和生态建设的发展,但目前分析林分和景观水平因子对松材线虫病综合影响的研究较少。本文基于松材线虫病危害后期的山东威海地区的松林,利用野外调... 松材线虫病(Pine wilt disease)传入我国以来,造成了大面积松林枯死,严重威胁我国的林业和生态建设的发展,但目前分析林分和景观水平因子对松材线虫病综合影响的研究较少。本文基于松材线虫病危害后期的山东威海地区的松林,利用野外调查数据、森林资源二类调查数据和高分辨率遥感影像,获取了影响松材线虫病危害的林分水平和景观水平的各种因子,通过逐步回归分析、线性回归分析和建立广义线性模型(GLM),探讨了景观分析的最适尺度,分析不同因子在解释松材线虫病危害程度方面的作用和相对重要性,以期为松材线虫病的防控技术及宏观管理政策制定提供科学依据。结果显示,750 m尺度下景观格局指数对松材线虫病发病率的解释效果最好。景观因子中,距疫源地距离、景观分离度与距人为活动区域距离对发病率影响最显著(相对重要性值为1.00),其中景观分离度和距疫源地距离与发病率呈负相关,距人为活动区域距离与发病率呈正相关;松林斑块连接度的相对重要性次之(相对重要性值为0.69),与发病率呈正相关;斑块丰富度密度、相关外接圆指数的相对重要性值较低(0.33)。林分因子中,林分密度的相对重要性值最低(0.23)。综合分析林分因子和景观因子的作用发现,在威海地区松材线虫病暴发后期的林分中,相较于林分因子,景观因子起主导作用。研究结果有助于提高对松材线虫病发生的驱动机制的了解。 展开更多
关键词 松材线虫病 林分因子 景观因子 最适尺度 广义线性模型
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Atomic Dispersed Hetero‑Pairs for Enhanced Electrocatalytic CO_(2)Reduction
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作者 Zhaoyong Jin Meiqi Yang +13 位作者 Yilong Dong Xingcheng Ma Ying Wang Jiandong Wu Jinchang Fan Dewen Wang Rongshen Xi Xiao Zhao Tianyi Xu Jingxiang Zhao Lei Zhang David J.Singh Weitao Zheng Xiaoqiang Cui 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第1期55-67,共13页
Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,in... Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,increasing the binding of the*COOH to the active site will generally increase the*CO desorption energy.Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO_(2)RR,but remains an unsolved challenge.Herein,we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier.This system shows an unprecedented CO_(2)RR intrinsic activity with TOF of 3336 h−1,high selectivity toward CO production,Faradaic efficiency of 95.96%at−0.60 V and excellent stability.Theoretical calculations show that the Mo-Fe diatomic sites increased the*COOH intermediate adsorption energy by bridging adsorption of*COOH intermediates.At the same time,d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of*CO intermediates.Thus,the undesirable correlation between these steps is broken.This work provides a promising approach,specifically the use of di-atoms,for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale. 展开更多
关键词 CO_(2)reduction reaction Atomic dispersed catalyst Hetero-diatomic pair Ad-desorption energy linear scaling relation
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利用改进的Hausdorff距离匹配多尺度线要素
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作者 铁占琦 《地理空间信息》 2024年第5期62-65,共4页
传统Hausdorff距离对噪声较敏感,在进行多尺度线要素匹配时,易导致漏匹配和误匹配。为提高匹配正确率,提出了一种改进的Hausdorff距离算法。针对部分匹配问题,采用曲线分割算法,以短曲线分割长曲线;针对点位分布差异问题,采用曲线加密算... 传统Hausdorff距离对噪声较敏感,在进行多尺度线要素匹配时,易导致漏匹配和误匹配。为提高匹配正确率,提出了一种改进的Hausdorff距离算法。针对部分匹配问题,采用曲线分割算法,以短曲线分割长曲线;针对点位分布差异问题,采用曲线加密算法,以匹配曲线的中间节点进行双向加密;针对曲线点集自身的噪声问题,以距离集合的中位数作为相似性指标,判断匹配要素是否为同名要素。选取不同尺度的行政区划界线和道路网数据进行匹配,以验证该算法。结果表明,该算法具有较好的匹配效果。 展开更多
关键词 多尺度线要素 要素匹配 HAUSDORFF距离 相似性指标
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可移动民宿的语义分析与设计策略
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作者 冯犇湲 蒋俊杰 《家具与室内装饰》 北大核心 2024年第1期120-127,共8页
可移动民宿是可移动建筑的衍生产品,其更符合现代人惬意随性、四处为家的旅行态度,并能促使民宿行业健康发展。文章首先梳理了可移动民宿这一概念,继而基于语义差分法,建立语义体系,结合意象尺度图寻求产品特定的语义偏好,分析语义呈现... 可移动民宿是可移动建筑的衍生产品,其更符合现代人惬意随性、四处为家的旅行态度,并能促使民宿行业健康发展。文章首先梳理了可移动民宿这一概念,继而基于语义差分法,建立语义体系,结合意象尺度图寻求产品特定的语义偏好,分析语义呈现与设计趋势,再后为进一步助推实践活动,以线性回归分析的方式挖掘语义项目对居住意愿的影响情况,明晰设计侧重,并以此输出案例。最终设计案例通过了语义评估,证明了设计策略的可行性。文章为可移动民宿正名,并为其设计发展提供了思路。 展开更多
关键词 可移动建筑 可移动民宿 语义差分法 意象尺度图 线性回归分析
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考虑声源尺度的声屏障插入损失优化算法
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作者 李志强 郑撼 +1 位作者 刘兰华 江楠 《环境影响评价》 2024年第1期62-66,共5页
声屏障与声源距离较近时,声源尺度对其插入损失计算结果有较大影响。将声源细化为多个子声源能提高准确度,但会导致计算过程复杂化。以靠近声屏障的线声源为研究对象,利用接收点至声屏障顶点的延伸线将声源划分为两部分,提出一种对声源... 声屏障与声源距离较近时,声源尺度对其插入损失计算结果有较大影响。将声源细化为多个子声源能提高准确度,但会导致计算过程复杂化。以靠近声屏障的线声源为研究对象,利用接收点至声屏障顶点的延伸线将声源划分为两部分,提出一种对声源动态划分的插入损失修正公式,从声屏障对噪声源不同区域的影响效果角度优化了插入损失计算方法。与将声源等效为单个线声源及划分为多个子线声源的计算结果对比表明,该优化算法的计算结果近似于将声源划分为无限个子线声源的计算结果,但计算复杂度并未显著增加,既解决了声影区边界处插入损失突变的问题,又提高了插入损失计算的准确度,对提升噪声预测的精度、规划适宜的声屏障结构、提出经济有效的噪声防护措施等具有重要意义。 展开更多
关键词 声屏障 插入损失 线声源 声源尺度
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政府补助规模对技术创新的非线性影响效应——基于探索式和利用式技术创新的比较分析
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作者 赵全厚 周学腾 《经济问题》 北大核心 2024年第6期10-17,F0003,共9页
进入21世纪以来,中国及世界其他主要发达国家都越来越重视采取政府补助手段来激励企业进行技术创新,但是政府补助如何影响企业的技术创新,现有文献并没有得出一致的研究结论。将技术创新划分为探索式和利用式技术创新,在成本和收益分析... 进入21世纪以来,中国及世界其他主要发达国家都越来越重视采取政府补助手段来激励企业进行技术创新,但是政府补助如何影响企业的技术创新,现有文献并没有得出一致的研究结论。将技术创新划分为探索式和利用式技术创新,在成本和收益分析框架下比较了政府补助对两种不同类型技术创新的差异化影响效应,并运用中国上市公司的数据对所提出的假设关系进行了实证检验。研究结果表明:政府补助规模对企业探索式技术创新具有“S”型影响效应,而对利用式技术创新则具有倒“U”型影响效应。这表明政府补助对探索式技术创新有先促进、后阻碍、再促进的三阶段影响效应,而对于利用式技术创新则起着先促进、后阻碍的两段式影响效应。研究结论为制定合理的政府补助政策提供了理论借鉴。 展开更多
关键词 政府补助规模 探索式技术创新 利用式技术创新 非线性关系
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Modified Augmented Lagrange Multiplier Methods for Large-Scale Chemical Process Optimization 被引量:6
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作者 梁昔明 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2001年第2期167-172,共6页
Chemical process optimization can be described as large-scale nonlinear constrained minimization. The modified augmented Lagrange multiplier methods (MALMM) for large-scale nonlinear constrained minimization are studi... Chemical process optimization can be described as large-scale nonlinear constrained minimization. The modified augmented Lagrange multiplier methods (MALMM) for large-scale nonlinear constrained minimization are studied in this paper. The Lagrange function contains the penalty terms on equality and inequality constraints and the methods can be applied to solve a series of bound constrained sub-problems instead of a series of unconstrained sub-problems. The steps of the methods are examined in full detail. Numerical experiments are made for a variety of problems, from small to very large-scale, which show the stability and effectiveness of the methods in large-scale problems. 展开更多
关键词 求解方法 大规模约束最小化问题 修改增广拉格朗日乘子法 化学工程 最优化 数值实验
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NON-LINEAR FORCED VIBRATION OF AXIALLY MOVING VISCOELASTIC BEAMS 被引量:17
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作者 Yang Xiaodong Chen Li-Qun 《Acta Mechanica Solida Sinica》 SCIE EI 2006年第4期365-373,共9页
The non-linear forced vibration of axially moving viscoelastic beams excited by the vibration of the supporting foundation is investigated. A non-linear partial-differential equation governing the transverse motion is... The non-linear forced vibration of axially moving viscoelastic beams excited by the vibration of the supporting foundation is investigated. A non-linear partial-differential equation governing the transverse motion is derived from the dynamical, constitutive equations and geometrical relations. By referring to the quasi-static stretch assumption, the partial-differential non-linearity is reduced to an integro-partial-differential one. The method of multiple scales is directly applied to the governing equations with the two types of non-linearity, respectively. The amplitude of near- and exact-resonant steady state is analyzed by use of the solvability condition of eliminating secular terms. Numerical results are presented to show the contributions of foundation vibration amplitude, viscoelastic damping, and nonlinearity to the response amplitude for the first and the second mode. 展开更多
关键词 axially moving beam VISCOELASTICITY non-linear forced vibration method of multiple scales
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Decentralized H-infinity state feedback control for discrete-time singular large-scale systems 被引量:3
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作者 Songlin WO 1 , Yun ZOU 2 , Shengyuan XU 2 (1.School of Electrical and Information Engineering, Jiangsu Teachers University of Technology, Changzhou Jiangsu 213001, China 2.School of Automation, Nanjing University of Science and Technology, Nanjing Jiangsu 210094, China) 《控制理论与应用(英文版)》 EI 2010年第2期200-204,共5页
The decentralized H-infinity control problem for discrete-time singular large-scale systems is considered. Based on the bounded real lemma of discrete-time singular systems, a sufficient condition for the existence of... The decentralized H-infinity control problem for discrete-time singular large-scale systems is considered. Based on the bounded real lemma of discrete-time singular systems, a sufficient condition for the existence of decentralized H-infinity controller for discrete-time singular large-scale systems is presented in terms of the solvability to a certain system of linear matrix inequalities by linear matrix inequality (LMI) approach, and the feasible solutions to the system of LMIs provide a parameterized representation of a set of decentralized H-infinity controller. The given example shows the application of the method. 展开更多
关键词 Discrete-time singular large-scale system linear matrix inequality (LMI) Decentralized H-infinity control
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Asymptotic analysis on weakly forced vibration of axially moving viscoelastic beam constituted by standard linear solid model
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作者 王波 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2012年第6期817-828,共12页
The weakly forced vibration of an axially moving viscoelastic beam is inves- tigated. The viscoelastic material of the beam is constituted by the standard linear solid model with the material time derivative involved.... The weakly forced vibration of an axially moving viscoelastic beam is inves- tigated. The viscoelastic material of the beam is constituted by the standard linear solid model with the material time derivative involved. The nonlinear equations governing the transverse vibration are derived from the dynamical, constitutive, and geometrical relations. The method of multiple scales is used to determine the steady-state response. The modulation equation is derived from the solvability condition of eliminating secular terms. Closed-form expressions of the amplitude and existence condition of nontrivial steady-state response are derived from the modulation equation. The stability of non- trivial steady-state response is examined via the Routh-Hurwitz criterion. 展开更多
关键词 axially moving beam weakly forced vibration standard linear solid model method of multiple scales steady-state response
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激光云粒子成像探测仪研制 被引量:1
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作者 史晓丁 冯力天 +3 位作者 刘英 杨泽后 伍波 石磊 《激光技术》 CAS CSCD 北大核心 2023年第1期67-72,共6页
为了研究云粒子微观特性,采用激光成像技术、高斯光束匀化处理技术、高分辨率阵列探测器以及图像抽帧还原算法,研制出激光云粒子成像仪。通过地面模拟测量及实际飞行试验,对仪器性能进行了测试。结果表明,研制仪器可实现对25μm~1550μ... 为了研究云粒子微观特性,采用激光成像技术、高斯光束匀化处理技术、高分辨率阵列探测器以及图像抽帧还原算法,研制出激光云粒子成像仪。通过地面模拟测量及实际飞行试验,对仪器性能进行了测试。结果表明,研制仪器可实现对25μm~1550μm云粒子的成像,分辨率为25μm,粒径测量误差小于9.5%;实测的冰晶粒子形态符合云粒子自然分布规律,粒子尺度谱符合指数分布,决定系数在0.58~0.97之间。该研制仪器可为云降水微物理研究提供基础观测数据。 展开更多
关键词 激光技术 云粒子探测仪 线阵成像 尺度谱
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Multi-scale Simulation Method with Coupled Finite/Discrete Element Model and Its Application 被引量:1
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作者 FANG Xiwu LIU Zhenyu +2 位作者 TAN Jianrong QIU Chan CHEN Fengbei 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第4期659-667,共9页
The existing research on continuous structure is usually analyzed with finite element method (FEM) and granular medium with discrete element method (DEM), but there are few researches on the coupling interaction betwe... The existing research on continuous structure is usually analyzed with finite element method (FEM) and granular medium with discrete element method (DEM), but there are few researches on the coupling interaction between continuous structure and discrete medium. To the issue of this coupling interaction, a multi-scale simulation method with coupled finite/discrete element model is put forward, in their respective domains of discrete and finite elements, the nodes follow force law and motion law of their own method, and on the their interaction interface, the touch type between discrete and finite elements is distinguished as two types: full touch and partial touch, the interaction force between them is calculated with linear elastic model. For full touch, the contact force is proportional to the overlap distance between discrete element and finite element patch. For partial touch, first the finite element patch is extended on all sides indefinitely to be a complete plane, the full contact force can be obtained with the touch type between discrete element and plane being viewed as full touch, then the full overlap area between them and the actual overlap area between discrete element and finite element patch are computed, the actual contact force is obtained by scaling the full contact force with a factor which is determined by the ratio of the actual overlap area to the full overlap area. The contact force is equivalent to the finite element nodes and the force and displacement on the nodes can be computed, so the ideal simulation results can be got. This method has been used to simulate the cutter disk of the earth pressure balance shield machine (EPBSM) made in North Heavy Industry (NHI) with its excavation diameter of 6.28 m cutting and digging the sandy clay layer. The simulation results show that as the gradual increase of excavating depth of the cutter head, the maximum stress occurs at the roots of cutters on the cutter head, while for the soil, the largest stress is distributed at the region which directly contacted with the cutters. The proposed research can provide good solutions for correct design and installation of cutters, and it is necessary to design mounting bracket to fix cutters on cutter head. 展开更多
关键词 MULTI-scale finite element discrete element linear elastic model
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Exponential Dichotomies and Fredholm Operators of Dynamic Equations on Time Scales
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作者 Le Huy Tien Le Duc Nhien 《Applied Mathematics》 2019年第1期39-50,共12页
For time-varying non-regressive linear dynamic equations on a time scale with bounded graininess, we introduce the concept of the associative operator with linear systems on time scales. The purpose of this research i... For time-varying non-regressive linear dynamic equations on a time scale with bounded graininess, we introduce the concept of the associative operator with linear systems on time scales. The purpose of this research is the characterizations of the exponential dichotomy obtained in terms of Fredholm property of that associative operator. Particularly, we use Perron’s method, which was generalized on time scales by J. Zhang, M. Fan, H. Zhu in?[1], to show that if the associative operator is semi-Fredholm then the corresponding linear nonautonomous equation has an exponential dichotomy on both?T?+?and?T-.??Moreover, we also give the converse result that the linear systems have?an exponential dichotomy on both?T?+?andT-??then the associative operator is Fredholm on?T. 展开更多
关键词 EXPONENTIAL DICHOTOMY FREDHOLM OPERATOR Time scales linear Dynamic EQUATION
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