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基于模态试验的连接结构状态表征参数研究 被引量:2
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作者 肖世富 刘信恩 杜强 《振动与冲击》 EI CSCD 北大核心 2011年第4期60-63,共4页
有效辨识螺栓连接结构的连接状态,是确保结构可靠性和安全性的基础。传统的基于模态参数辨识结构连接状态变化的方法效果不太理想,从模态理论出发,在基准模态空间中构造了相对模态复/实连接刚度两类特征参数表征结构的连接状态,并采用... 有效辨识螺栓连接结构的连接状态,是确保结构可靠性和安全性的基础。传统的基于模态参数辨识结构连接状态变化的方法效果不太理想,从模态理论出发,在基准模态空间中构造了相对模态复/实连接刚度两类特征参数表征结构的连接状态,并采用不同拧紧力矩下的螺栓连接梁模态试验对构造的表征参数的有效性进行了检验。结果表明,所构造的表征参数比固有频率对连接状态变化具有更好的敏感性。 展开更多
关键词 连接状态辨识 模态试验 相对模态连接刚度 放大系数
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基于模态柔度相对变化量的结构损伤识别
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作者 刘天怡 彭凯 《山西建筑》 2010年第10期63-64,共2页
介绍了支持向量机的分类算法,构造了基于模态柔度相对变化量的损伤识别指标,并将此指标作为支持向量机的特征参数进行训练和结构的损伤识别,通过对简支梁仿真计算及试验结果表明:支持向量机对结构损伤的识别有着良好的抗噪性能,该方法... 介绍了支持向量机的分类算法,构造了基于模态柔度相对变化量的损伤识别指标,并将此指标作为支持向量机的特征参数进行训练和结构的损伤识别,通过对简支梁仿真计算及试验结果表明:支持向量机对结构损伤的识别有着良好的抗噪性能,该方法对梁的损伤位置有较高的识别能力。 展开更多
关键词 支持向量机 结构损伤识别 模态柔度相对变化量 抗噪性能
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高速切削机床横梁的静态与动态分析 被引量:32
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作者 侯红玲 邱志惠 赵永强 《机械设计与制造》 北大核心 2006年第5期38-39,共2页
在机床设计的初期,利用有限元分析软件ANSYS,在材料和截面空间尺寸相似的情况下,对截面形状不同的几种结构的梁进行静力和模态分析,将强度较好的梁,用模态分析得到刚度更好的梁。通过结构的变形和一阶频率的振型研究比较,初步确定了较... 在机床设计的初期,利用有限元分析软件ANSYS,在材料和截面空间尺寸相似的情况下,对截面形状不同的几种结构的梁进行静力和模态分析,将强度较好的梁,用模态分析得到刚度更好的梁。通过结构的变形和一阶频率的振型研究比较,初步确定了较为合理的横梁结构。 展开更多
关键词 截面形状 强度 刚度 模态分析 振动模态相对位移量
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New Agegraphic Dark Energy in Brans-Dicke Theory 被引量:1
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作者 LIU Xiang-Lai ZHANG Xin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第10期761-768,共8页
In this paper, we investigate the new agegraphic dark energy model in the framework of Brans-Dicke theory, which is a natural extension of the Einstein's general relativity. In this framework the form of the new ageg... In this paper, we investigate the new agegraphic dark energy model in the framework of Brans-Dicke theory, which is a natural extension of the Einstein's general relativity. In this framework the form of the new agegraphic dark energy density takes as pq = 3n^2Ф(t)η^-2, where η is the conformal age of the universe and Ф(t) is the Brans-Dicke scalar field representing the inverse of the time-variable Newton's constant. We derive the equation of state of the new agegraphic dark energy and the deceleration parameter of the universe in the Brans-Dicke theory. It is very interesting to find that in the Brans-Dicke theory the agegraphic dark energy realizes quintom-like behavior, i.e., its equation of state crosses the phantom divide ω= -1 during the evolution. We also compare the situation of the agegraphic dark energy model in the Brans-Dicke theory with that in the Einstein's theory. In addition, we discuss the new agegraphic dark energy model with interaction in the framework of the Brans-Dicke theory. 展开更多
关键词 agegraphic dark energy quantum gravity cosmic acceleration Brans--Dicke theory
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Ground State Meson Spectrum in a Relativistic Model with Instanton Induced Interaction 被引量:1
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作者 Antony Prakash Monteiro K.B.Vijaya Kumar 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第2期325-330,共6页
The mass spectrum of the S-wave mesons is considered in the frame work of relativistic harmonic model (RHM). The full Hamiltonian used in the investigation has the Lorentz scalar plus a vector harmonic-oscillator po... The mass spectrum of the S-wave mesons is considered in the frame work of relativistic harmonic model (RHM). The full Hamiltonian used in the investigation has the Lorentz scalar plus a vector harmonic-oscillator potential, the confined-one-gluon-exchange potential (COGEP) and the instanton-induced quark-antiquak interaction (Ⅲ). A good description of the mass spectrum is obtained. The respective role of Ⅲ and COGEP in the S-wave meson spectrum is discussed. 展开更多
关键词 quark model confined-one-gluon-exchange potential instanton induced interaction S-wave spectra
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Solubility of red palm oil in supercritical carbon dioxide: Measurement and modelling 被引量:1
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作者 Wan Jun Lee Chin Ping Tan +1 位作者 Rabiha Sulaiman Gun Hean Chong 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第5期964-969,共6页
The solubility of red palm oil (RPO) in supercritical carbon dioxide (scCO2) was determined using a dynamic method at 8.5-25 MPa and, 313.15-333.15 K and at a fixed scCO2 flow rate of 2.9 g. mn -1 using a full fac... The solubility of red palm oil (RPO) in supercritical carbon dioxide (scCO2) was determined using a dynamic method at 8.5-25 MPa and, 313.15-333.15 K and at a fixed scCO2 flow rate of 2.9 g. mn -1 using a full factorial design. The solubility was determined under low pressures and temperatures as a preliminary study for RPO par- ticle formation using scCO2. The solubility of RPO was 0.5-11.3 mg. (g CO2) -1 and was significantly affected by the pressure and temperature. RPO solubility increased with pressure and decreased with temperature. The Adachi-Lu model showed the best-fit for RPO solubility data with an average relative deviation of 14% with a high coefficient of determination, R2 of 0.9667, whereas the Peng-Robinson equation of state thermodynamic model recorded deviations of 17%-30%. 展开更多
关键词 SOLUBILITY Supercritical carbon dioxide Mathematical modelling THERMODYNAMICS Palm oil
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Support Vector Machines(SVM)-Markov Chain Prediction Model of Mining Water Inflow 被引量:2
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作者 Kai HUANG 《Agricultural Science & Technology》 CAS 2017年第8期1551-1554,1558,共5页
This study was conducted to establish a Support Vector Machines(SVM)-Markov Chain prediction model for prediction of mining water inflow. According to the raw data sequence, the Support Vector Machines(SVM) model was ... This study was conducted to establish a Support Vector Machines(SVM)-Markov Chain prediction model for prediction of mining water inflow. According to the raw data sequence, the Support Vector Machines(SVM) model was built, and then revised by means of a Markov state change probability matrix. Through dividing the state and analyzing absolute errors and relative errors and other indexes of the measured value and the fitted value of SVM, the prediction results were improved. Finally,the model was used to calculate relative errors. Through predicting and analyzing mining water inflow, the prediction results of the model were satisfactory. The results of this study enlarge the application scope of the Support Vector Machines(SVM) prediction model and provide a new method for scientific forecasting water inflow in coal mining. 展开更多
关键词 Mining water inflow Support Vector Machines (SVM) Markov Chain
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Time series prediction of mining subsidence based on a SVM 被引量:9
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作者 Li Peixian Tan Zhixiang +1 位作者 Yan Lili Deng Kazhong 《Mining Science and Technology》 EI CAS 2011年第4期557-562,共6页
In order to study dynamic laws of surface movements over coal mines due to mining activities,a dynamic prediction model of surface movements was established,based on the theory of support vector machines(SVM) and time... In order to study dynamic laws of surface movements over coal mines due to mining activities,a dynamic prediction model of surface movements was established,based on the theory of support vector machines(SVM) and times-series analysis.An engineering application was used to verify the correctness of the model.Measurements from observation stations were analyzed and processed to obtain equal-time interval surface movement data and subjected to tests of stationary,zero means and normality.Then the data were used to train the SVM model.A time series model was established to predict mining subsidence by rational choices of embedding dimensions and SVM parameters.MAPE and WIA were used as indicators to evaluate the accuracy of the model and for generalization performance.In the end,the model was used to predict future surface movements.Data from observation stations in Huaibei coal mining area were used as an example.The results show that the maximum absolute error of subsidence is 9 mm,the maximum relative error 1.5%,the maximum absolute error of displacement 7 mm and the maximum relative error 1.8%.The accuracy and reliability of the model meet the requirements of on-site engineering.The results of the study provide a new approach to investigate the dynamics of surface movements. 展开更多
关键词 Support vector machine Mining subsidence Time series Dynamic prediction
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从可能到必然——贯穿普兰丁格本体论证明的逻辑之旅 被引量:2
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作者 张力锋 《学术月刊》 CSSCI 北大核心 2011年第9期51-59,共9页
普兰丁格使用模态逻辑S5及其可能世界语义学作为论证工具,并运用可能世界、世界索引性质、个体本质和示例等基本哲学概念之间的内在逻辑联系,在辩明极大伟大性、极大美德性及全能、全知和道德完美三者之间关系的基础之上,证明上帝的存... 普兰丁格使用模态逻辑S5及其可能世界语义学作为论证工具,并运用可能世界、世界索引性质、个体本质和示例等基本哲学概念之间的内在逻辑联系,在辩明极大伟大性、极大美德性及全能、全知和道德完美三者之间关系的基础之上,证明上帝的存在。这一本体论证明的最大贡献在于摆脱了康德式"存在不是谓词"的责难。它不但在形式上是有效的,而且更为形象直观,极大扩展了本质主义学说的内涵。但其主要前提的可靠性并未得到有力证成,至大可能性的模态直觉辩护需要更详尽的澄清,至大的可能性属于相对模态,绝非形而上学模态,二者不可等同视之;它使用的论证工具模态逻辑S5是否正确的形而上学模态逻辑也存在着广泛争议。 展开更多
关键词 上帝 可能世界 个体本质 示例 模态逻辑S5 形而上学模态 认知模态 相对模态
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Experimental measurement of covariance matrix of two-mode entangled state 被引量:2
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作者 YU XuDong LI Wei +1 位作者 JIN YuanBin ZHANG Jing 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第5期875-879,共5页
A two-mode entangled state was generated experimentally through mixing two squeezed lights from two optical parametric amplifiers on a 50/50 beam splitter.The entangled beams were measured by means of two pairs of bal... A two-mode entangled state was generated experimentally through mixing two squeezed lights from two optical parametric amplifiers on a 50/50 beam splitter.The entangled beams were measured by means of two pairs of balanced homodyne detection systems respectively.The relative phases between the local beams and the detected beams can be locked by using the optical phase modulation technique.The covariance matrix of the two-mode entangled state was obtained when the relative phase of the local beam and the detected beam in one homodyne detection system is locked and the other is scanned.This method provides a way by which one can extract the covariance matrix of any selected quadrature components of two-mode Gaussian state. 展开更多
关键词 optical parametric amplifier Gaussian entangled state covariance matrix
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