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Entropy-Based Global and Local Weight Adaptive Image Segmentation Models
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作者 Gang Li Yi Zhao +3 位作者 Ling Zhang Xingwei Wang Yueqin Zhang Fayun Guo 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2020年第1期149-160,共12页
This paper proposes a parameter adaptive hybrid model for image segmentation. The hybrid model combines the global and local information in an image, and provides an automated solution for adjusting the selection of t... This paper proposes a parameter adaptive hybrid model for image segmentation. The hybrid model combines the global and local information in an image, and provides an automated solution for adjusting the selection of the two weight parameters. Firstly, it combines an improved local model with the global Chan-Vese(CV) model, while the image’s local entropy is used to establish the index for measuring the image’s gray-level information. Parameter adjustment is then performed by the real-time acquisition of the ratio of the different functional energy in a self-adapting model responsive to gray-scale distribution in the image segmentation process.Compared with the traditional linear adjustment model, which is based on trial-and-error, this paper presents a more quantitative and intelligent method for achieving the dynamic nonlinear adjustment of global and local terms.Experiments show that the proposed model achieves fast and accurate segmentation for different types of noisy and non-uniform grayscale images and noise images. Moreover, the method demonstrates high stability and is insensitive to the position of the initial contour. 展开更多
关键词 IMAGE local ENTROPY PARAMETER ADAPTION IMAGE SEGMENTATION active CONTOUR
Experimental study of near-bed concentration and sediment verticalmixing parameter for vertical concentration distribution in the surfzone 预览
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作者 Yang Zhang Zhili Zou +1 位作者 Wushan Xue Dapeng Sun 《国际泥沙研究:英文版》 SCIE 2020年第1期27-41,共15页
Two formulae for the near-bed concentration(Ca)and the sediment vertical mixing parameter(m)are established based on a large scale wave flume experiment.The advantage of the new formulae is that the turbulent kinetic ... Two formulae for the near-bed concentration(Ca)and the sediment vertical mixing parameter(m)are established based on a large scale wave flume experiment.The advantage of the new formulae is that the turbulent kinetic energy induced by wave breaking can be taken into account;the formula for Ca is in terms of the near-bed,time-averaged turbulent kinetic energy,and the formula for m is in terms of depth-and time-averaged turbulent kinetic energy.A new expression for suspended sediment load also is established by depth integration of the vertical distribution of the suspended sediment concentration obtained on basis of the new formulae.Equation validation is done by comparing the predicted Ca and m to measurements for different types of waves(regular wave,wave group,and irregular wave),and good agreement is found.The advantages of the proposed formulae over previous formulae also are discussed. 展开更多
关键词 Near-bed concentration Sediment vertical mixing parameter Turbulent kinetic energy Surf zone Wave type
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Statistical Analysis of Two-Parameter Generalized BS-Logistic Fatigue Life Distribution
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作者 XU Xiaoling WANG Ronghua GU Beiqing 《系统科学与复杂性学报:英文版》 SCIE EI CSCD 2019年第4期1231-1250,共20页
The logarithmic moment estimations of parameters are proposed for two-parameter generalized Birnbaum-Saunders Logistic fatigue life distribution GBS-Logistic(α,β)under the full sample.The precisions of point estimat... The logarithmic moment estimations of parameters are proposed for two-parameter generalized Birnbaum-Saunders Logistic fatigue life distribution GBS-Logistic(α,β)under the full sample.The precisions of point estimations are investigated and compared with other point estimations by Monte-Carlo simulations.The approximate interval estimations of parameters are given by using Taylor expansion,and the precisions of approximate interval estimations are investigated by Monte-Carlo simulations.Finally,several examples show the feasibility of the methods. 展开更多
关键词 Approximate interval ESTIMATION point ESTIMATION scale PARAMETER shape PARAMETER TWO-PARAMETER GENERALIZED Birnbaum-Saunders LOGISTIC fatigue life DISTRIBUTION
基于管道流量监测数据的城市雨洪模型实用性研究 预览
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作者 宋磊 杜龙刚 +3 位作者 黄涛 史德雯 杨卓 姜其贵 《水文》 CSCD 北大核心 2019年第3期22-28,共7页
在总结过去多年管道流量监测经验教训的基础上,创新使用多声道多普勒流量计,成功获取了5min频次的雨水管网流量过程,提升了监测的稳定性和监测结果的可靠性,使得利用多场次资料进行城市内涝模型参数率定以及验证成为可能。选取城市典型... 在总结过去多年管道流量监测经验教训的基础上,创新使用多声道多普勒流量计,成功获取了5min频次的雨水管网流量过程,提升了监测的稳定性和监测结果的可靠性,使得利用多场次资料进行城市内涝模型参数率定以及验证成为可能。选取城市典型区域,分别建立了MIKE、SWMM、InfoWorks一维管网模型,并按照有关规范要求,在对降雨资料和水位、流量资料进行科学分析后,利用经过筛选的有效数据进行模型的参数校核和率定,经过验证符合《内涝防治系统数学模型应用技术规程》要求。通过误差分析,率定后的模型,对典型区域的管网汇流模拟较好,在内涝分析预测预报中精度较高,其流量峰值预测值与实测值的误差在10%以内。 展开更多
关键词 城市水文 内涝 管道流量 模型参数 参数率定 研究
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Hydrodynamic characteristics of 30%TBP/kerosene-HNO3 solution system in an annular centrifugal contactor 预览
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作者 Hong-Lin Chen Jian-Chen Wang +1 位作者 Wu-Hua Duan Jing Chen 《核技术:英文版》 SCIE CAS CSCD 2019年第6期16-27,共12页
Annular centrifugal contactors (ACCs) have many advantages and are recognized as key solvent-extraction equipment for the future reprocessing of spent nuclear fuel (RSNF). To successfully design and operate ACCs for R... Annular centrifugal contactors (ACCs) have many advantages and are recognized as key solvent-extraction equipment for the future reprocessing of spent nuclear fuel (RSNF). To successfully design and operate ACCs for RSNF, it is necessary to understand the hydrodynamic characteristics of the extraction systems in ACCs. The phase ratio (R = Vaq/Vorg, A/O) and liquid holdup volume (V) of the ACC are important hydrodynamic characteristics. In this study, a liquid-fast-separation method was used to systematically investigate the effects of the operational and structural parameters on the V and R (A/O) of a φ20 ACC by using a 30%TBP/kerosene- HNO3 solution system. The results showed that the operational and structural parameters had different effects on the V and R (A/O) of the mixing and separating zones of the ACC, respectively. For the most frequently used structural parameters of the φ20 ACC, when the rotor speed was 3500 r/min, the total flow rate was 2.0 L/h, and the flow ratio (A/O) was 1, the liquid holdup volumes in the mixing zone and rotor were 8.03 and 14.0 mL, respectively, and the phase ratios (A/O) of the mixing zone and separating zone were 0.96 and 1.43, respectively. 展开更多
关键词 ANNULAR CENTRIFUGAL CONTACTOR Liquid-fastseparation method Phase ratio (A/O) LIQUID HOLDUP volume Structural PARAMETER Operational PARAMETER
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Parameter Optimization of Regularization Variational Merging and Its Application in GNSS/MET Water Vapor 预览
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作者 Wang Gen Zhou Shuxue +1 位作者 Ding Xia Liu Huilan 《气象与环境研究:英文版》 CAS 2019年第2期44-50,共7页
The paper discusses the core parameters of the 3 D and 4 D variational merging based on L1 norm regularization,namely optimization characteristic correlation length of background error covariance matrix and regulariza... The paper discusses the core parameters of the 3 D and 4 D variational merging based on L1 norm regularization,namely optimization characteristic correlation length of background error covariance matrix and regularization parameter. Classical 3 D/4 D variational merging is based on the theory that error follows Gaussian distribution. It involves the solution of the objective functional gradient in minimization iteration,which requires the data to have continuity and differentiability. Classic 3 D/4 D-dimensional variational merging method was extended,and L1 norm was used as the constraint coupling to the classical variational merged model. Experiment was carried out by using linear advection-diffusion equation as four-dimensional prediction model,and parameter optimization of this method is discussed. Considering the strong temporal and spatial variation of water vapor,this method is further applied to the precipitable water vapor( PWV) merging by calculating reanalysis data and GNSS retrieval.Parameters were adjusted gradually to analyze the influence of background field on the merging result,and the experiment results show that the mathematical algorithm adopted in this paper is feasible. 展开更多
关键词 VARIATIONAL MERGING L1 NORM PARAMETER optimization Precipitable water vapor REGULARIZATION PARAMETER
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真三轴条件下原状黄土的非线性本构模型
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作者 方瑾瑾 冯以鑫 +2 位作者 赵伟龙 王立平 余永强 《岩土力学》 EI CAS CSCD 北大核心 2019年第2期517-528,共12页
为了研究复杂应力条件下非饱和原状黄土的非线性本构模型,通过考虑真三轴条件下中主应力和吸力对大主应变的影响,提出了一个考虑中主应力影响的非饱和原状黄土的非线性本构模型。该模型包含12个参数,均可由常含水率非饱和土真三轴试验... 为了研究复杂应力条件下非饱和原状黄土的非线性本构模型,通过考虑真三轴条件下中主应力和吸力对大主应变的影响,提出了一个考虑中主应力影响的非饱和原状黄土的非线性本构模型。该模型包含12个参数,均可由常含水率非饱和土真三轴试验确定。研究了中主应力对土体变形和强度的影响,探讨了模型参数的变化规律。初始吸力一定时,土体的黏聚力随着中主应力的增大而增大,而内摩擦角随着中主应力的增大呈线性减小趋势。当吸力小于162 kPa时,吸力摩擦角等于21.8°;当吸力大于162 kPa时,吸力摩擦角等于5.5°。初始吸力相同时,不同中主应力条件下土体的体积模量可取为常数。利用该模型预估了常含水率真三轴等向固结试验的吸力变化规律,理论结果与试验结果比较接近。但是对于真三轴剪切试验吸力的预估还需要进行深入探讨。 展开更多
关键词 非线性本构模型 非饱和土真三轴仪 中主应力 参数
基于IM-GA-BPNN的网络入侵检测算法设计 预览
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作者 周丽娟 《山西大同大学学报:自然科学版》 2019年第5期40-43,共4页
为了提高网络入侵检测系统的检测率、实时性和误报率,实现对网络进行有效的入侵检测,设计了一种基于免疫遗传算法和BP神经网络的网络入侵检测方法,首先建立四层的网络模型,采用训练数据对BP神经网络进行训练;为了进一步优化参数,通过免... 为了提高网络入侵检测系统的检测率、实时性和误报率,实现对网络进行有效的入侵检测,设计了一种基于免疫遗传算法和BP神经网络的网络入侵检测方法,首先建立四层的网络模型,采用训练数据对BP神经网络进行训练;为了进一步优化参数,通过免疫遗传算法对神经网络的参数进行优化,通过个体的复制、选择、交叉和变异来提高解的多样性,实现最优参数的求解。将KDD99 CUP入侵检测数据库中的数据作为仿真数据实验,将所提的模型IM-GA-BPNN与其它方法如BPNN、PCA-NN和PCA-PSO-NN进行比较,结果表明所提模型具有最高的检测率,同时具有检测效率高的优点。 展开更多
关键词 网络入侵检测 神经网络 免疫遗传 参数
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Analysis of ship wake features and extraction of ship motion parameters from SAR images in the Yellow Sea
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作者 Kaiguo FAN Huaguo ZHANG +3 位作者 Jianjun LIANG Peng CHEN Bojian XU Ming ZHANG 《地球科学前沿:英文版》 CSCD 2019年第3期588-595,共8页
The identifying features of ship wakes in synthetic aperture radar (SAR) remote sensing images are of great importance for detecting ships and for extracting ship motion parameters. A statistical analysis was conducte... The identifying features of ship wakes in synthetic aperture radar (SAR) remote sensing images are of great importance for detecting ships and for extracting ship motion parameters. A statistical analysis was conducted on the identifying features of ship wakes in SAR images in the Yellow Sea. In this study, 1091 ship wake sub-images were selected from 327 SAR images in the Yellow Sea near Qingdao. Analysis of the identifying features of ship wakes in SAR images revealed that both turbulent wakes and Kelvin wakes account for the majority of ship wakes, with turbulent wakes occurring approximately four times as frequently as Kelvin wakes. Narrow-V wakes and internal wave wakes were comparatively rare, which is due to the peculiarities of the radar system parameters and marine environments required to observe these wakes. Additionally, we extracted ship motion parameters from four types of ship wakes in the SAR images. Specifically, internal wave wakes in SAR images in the Yellow Sea were also used to extract ship motion parameters. Validation of the extracted parameters indicated that the extraction of these parameters from ship wakes is a viable and accurate approach for the acquisition of ship motion parameters. These results provide a solid foundation for the commercialization of SAR-based technologies for detecting ships and extracting ship motion parameters. 展开更多
关键词 SYNTHETIC APERTURE RADAR remote sensing SHIP WAKE SHIP motion parameter
核电厂人员闸门数字样机应用技术研究
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作者 谢洪虎 马文勤 +2 位作者 张峰 何英勇 杨锦春 《核动力工程》 EI CAS CSCD 北大核心 2019年第4期139-144,共6页
为提高核电厂人员闸门的安全、可靠性,基于数字样机技术,构建人员闸门整机和关键零部件的参数化模型,结合故障模式及影响分析(FMEA)方法,对人员闸门参数化模型进行可靠性分析,找到薄弱环节。并借助动力学仿真分析软件(ADAMS)和有限元分... 为提高核电厂人员闸门的安全、可靠性,基于数字样机技术,构建人员闸门整机和关键零部件的参数化模型,结合故障模式及影响分析(FMEA)方法,对人员闸门参数化模型进行可靠性分析,找到薄弱环节。并借助动力学仿真分析软件(ADAMS)和有限元分析软件(ANSYS),对人员闸门顶升机构和筒体与密封门组成的承压部件薄弱环节进行了动力学仿真分析和应力计算与评定。结果表明,人员闸门自身存在的薄弱环节不会导致其产生功能或结构完整性失效事故,验证了人员闸门数字样机结构设计的合理性、装配关系的正确性。 展开更多
关键词 人员闸门 数字样机 可靠性 参数化 仿真分析
Compatibility Evaluation between Direct Coal Liquefaction Residue and Bitumen 预览
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作者 Ji Jie Wu Hao +5 位作者 Xu Ying Suo Zhi Wei Jianming Dai Qingli Zhang Ran Diab Aboelkasim 《中国炼油与石油化工:英文版》 SCIE CAS 2019年第1期90-100,共11页
The compatibility between direct coal liquefaction residue(DCLR) and five kinds of pure bitumen(Shell-90,SK-90, ZSY-70, DM-70 and KLMY-50) was evaluated in this study. The rheological characteristics, glass transition... The compatibility between direct coal liquefaction residue(DCLR) and five kinds of pure bitumen(Shell-90,SK-90, ZSY-70, DM-70 and KLMY-50) was evaluated in this study. The rheological characteristics, glass transition temperatures(T_g), solubility parameters(SP) and SARA(saturates, aromatics, resins, and asphaltenes) fractions of DCLR,five kinds of pure bitumen and their blends(named as DCLR modified bitumen) were measured using the dynamic shear rheometer(DSR), differential scanning calorimetry(DSC), viscosity, and SARA tests, respectively. And the compatibility between DCLR and pure bitumen was characterized with three approaches, viz. the Cole-Cole plot,T_g, and the solubility parameter difference(SPD) method. Since each method has its own working mechanism, the compatibility ranking for the DCLR and five kinds of pure bitumen is slightly different according to the three approaches. However, the difference is pretty close and sometimes can be ignored. The general compatibility ranking decreases in the following order: Shell-90≈SK-90>DM-70≈ZSY-70>KLMY-50, which is affected by the asphaltenes content and the colloid index(I_c) value in the pure bitumen. Pure bitumen with lower asphaltenes content and colloid index(I_c) value has better compatibility with DCLR. 展开更多
关键词 direct coal LIQUEFACTION RESIDUE (DCLR) pure BITUMEN compatibility Cole-Cole PLOT glass state temperature (Tg) approach SOLUBILITY parameter difference (SPD) method
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Planar Cubic G1 Hermite Interpolant with Minimal Quadratic Oscillation in Average 预览
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作者 Li Jun-cheng 《数学研究通讯:英文版》 CSCD 2019年第3期219-224,共6页
In this paper we apply a new method to choose suitable free parameters of the planar cubic G1 Hermite interpolant. The method provides the cubic G1 Hermite interpolant with minimal quadratic oscillation in average. We... In this paper we apply a new method to choose suitable free parameters of the planar cubic G1 Hermite interpolant. The method provides the cubic G1 Hermite interpolant with minimal quadratic oscillation in average. We can use the method to construct the optimal shape-preserving interpolant. Some numerical examples are presented to illustrate the effectiveness of the method. 展开更多
关键词 CUBIC HERMITE interpolant free parameter optimization shape-preserving interpolant
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An improved radar detection and tracking method for small UAV under clutter environment
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作者 Cheng HU Yixuan WANG +3 位作者 Rui WANG Tianran ZHANG Jiong CAI Meiqin LIU 《中国科学:信息科学(英文版)》 SCIE EI CSCD 2019年第2期217-219,共3页
Dear editor,The unmanned aerial vehicle(UAV)is a popular aerial instrument in both military and civil fields [1].Radar is an efficient tool for aerial target surveillance and target parameter estimation [2]and has bee... Dear editor,The unmanned aerial vehicle(UAV)is a popular aerial instrument in both military and civil fields [1].Radar is an efficient tool for aerial target surveillance and target parameter estimation [2]and has been widely used for air control.However,in recent years,it has become a challenge for radar to monitor this kind of small and lowaltitude flying target [3].Therefore,it is necessary to investigate the detection and tracking techniques of UAVs. 展开更多
关键词 unmanned AERIAL necessary to INVESTIGATE PARAMETER ESTIMATION
Fuzzy impedance control of an electro-hydraulic actuator with an extended disturbance observer
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作者 Mingjie LI Jian-hua WEI +2 位作者 Jin-hui FANG Wen-zhuo SHI Kai GUO 《信息与电子工程前沿:英文版》 SCIE EI CSCD 2019年第9期1221-1233,共13页
In this paper,we deal with both velocity control and force control of a single-rod electro-hydraulic actuator subject to external disturbances and parameter uncertainties.In some implementations,both velocity control ... In this paper,we deal with both velocity control and force control of a single-rod electro-hydraulic actuator subject to external disturbances and parameter uncertainties.In some implementations,both velocity control and force control are required.Impedance control and an extended disturbance observer are combined to solve this issue.Impedance control is applied to regulate the dynamic relationship between the velocity and output force of the actuator,which can help avoid impact and keep a proper contact force on the environment or workpieces.Parameters of impedance rules are regulated by a fuzzy algorithm.An extended disturbance observer is employed to account for external disturbances and parameter uncertainties to achieve an accurate velocity tracking.A detailed model of load force dynamics is presented for the development of the extended disturbance observer.The stability of the whole system is analyzed.Experimental results demonstrate that the proposed control strategy has not only a high velocity tracking performance,but also a good force adjustment performance,and that it should be widely applied in construction and assembly. 展开更多
关键词 FUZZY CONTROL Impedance CONTROL Disturbance observer Parameter UNCERTAINTIES ELECTRO-HYDRAULIC ACTUATOR
一种利用射频仿真软件优化键合线形的方法
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作者 杨建军 冯斌 刘英坤 《微纳电子技术》 北大核心 2019年第6期499-504,共6页
半导体器件内键合线的线形复杂程度决定键合工序和调试工序的效率。以提高键合工序生产效率为目的,利用射频仿真软件对某成熟半导体器件内匹配线进行从手动键合向自动键合的优化。结合金丝球焊线形特点,进行研究方案设计,通过仿真和测... 半导体器件内键合线的线形复杂程度决定键合工序和调试工序的效率。以提高键合工序生产效率为目的,利用射频仿真软件对某成熟半导体器件内匹配线进行从手动键合向自动键合的优化。结合金丝球焊线形特点,进行研究方案设计,通过仿真和测试的方法,最终将手动键合丝形状优化为适合自动球焊键合机键合的线形。射频测试结果表明,优化前后器件的S参数测试结果一致性较好。该优化方案缩短了仿真周期,实现了器件生产从手动键合向自动键合转化,提高了生产效率,改善了器件的一致性,使该器件实现了调测阶段的免调试,满足了大批量生产要求。 展开更多
关键词 内匹配器件 自动键合 射频测试 自动球焊键合机 S参数
Derivation of lattice Boltzmann equation via analytical characteristic integral
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作者 叶欢锋 匡波 杨燕华 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期431-441,共11页
A lattice Boltzmann(LB) theory, the analytical characteristic integral(ACI) LB theory, is proposed in this paper.ACI LB theory takes the Bhatnagar–Gross–Krook(BGK)-Boltzmann equation as the exact kinetic equation be... A lattice Boltzmann(LB) theory, the analytical characteristic integral(ACI) LB theory, is proposed in this paper.ACI LB theory takes the Bhatnagar–Gross–Krook(BGK)-Boltzmann equation as the exact kinetic equation behind Navier–Stokes continuum and momentum equations and constructs an LB equation by rigorously integrating the BGK-Boltzmann equation along characteristics. It is a general theory, supporting most existing LB equations including the standard lattice BGK(LBGK) equation inherited from lattice-gas automata, whose theoretical foundation had been questioned. ACI LB theory also indicates that the characteristic parameter of an LB equation is collision number, depicting the particle-interaction intensity in the time span of the LB equation, instead of the traditionally assumed relaxation time, and the over-relaxation time problem is merely a manifestation of the temporal evolution of equilibrium distribution along characteristics under high collision number, irrelevant to particle kinetics. In ACI LB theory, the temporal evolution of equilibrium distribution along characteristics is the determinant of LB method accuracy and we numerically prove this. 展开更多
关键词 LATTICE Boltzmann(LB) equation ANALYTICAL CHARACTERISTIC INTEGRAL CHARACTERISTIC parameter
夹套结构内管泄漏声发射检测与评价方法 预览
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作者 于永亮 龙飞飞 刘永轩 《无损检测》 2019年第3期17-19,84共4页
由于夹套结构的遮蔽性,其内管泄漏很难及时发现。采用声发射检测技术,利用其实时性、高灵敏度等特点对夹套结构内管泄漏进行检测。构造了一个用于评价夹套内管泄漏的新的声发射参量,以提高评价的准确度。通过开展内管泄漏模拟试验,对传... 由于夹套结构的遮蔽性,其内管泄漏很难及时发现。采用声发射检测技术,利用其实时性、高灵敏度等特点对夹套结构内管泄漏进行检测。构造了一个用于评价夹套内管泄漏的新的声发射参量,以提高评价的准确度。通过开展内管泄漏模拟试验,对传统声发射参量与新参量评价效果进行了对比,结果表明新参量评价效果更准确。同时,采用互相关定位方法对夹套结构模拟泄漏点进行了定位,定位结果误差低于10%。结果表明,新构造的参量能准确地对泄漏强度进行评价,互相关定位可以确定内管泄漏的位置。 展开更多
关键词 夹套结构 内管泄漏 声发射 参量 定位
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基于响应面法的碎石道床离散元模型参数研究(英文)
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作者 Jie-ling XIAO Gan-zhong LIU +3 位作者 Jian-xing LIU Jia-cheng DAI Hao LIU Ping WANG 《浙江大学学报:A卷英文版》 SCIE EI CAS CSCD 2019年第9期685-700,共16页
目的:采用响应面方法研究特级道砟休止角的离散元参数仿真试验,建立多次回归模型并对其进行优化,以及对道砟接触参数进行优选。通过多参数的响应面法为碎石道床离散元参数的快速标定提供有效途径。创新点:1.基于响应面法对离散元道砟接... 目的:采用响应面方法研究特级道砟休止角的离散元参数仿真试验,建立多次回归模型并对其进行优化,以及对道砟接触参数进行优选。通过多参数的响应面法为碎石道床离散元参数的快速标定提供有效途径。创新点:1.基于响应面法对离散元道砟接触参数进行统计分析,提出道砟最优参数的回归方程及回归曲面。2.以道砟堆积体在多个正交平面的均值为道砟休止角,构建基于一致线性描述方式的道砟休止角实测试验与离散元仿真试验。3.提出道砟参数的动态标定思想。方法:1.通过道砟休止角的室内试验,测量出道砟休止角度的有效均值。2.以实测结果为目标,采用响应面法对道砟离散元仿真参数进行优选。3.验证所提方法的可行性和有效性。结论:1.通过采用休止角的4个正交面取均值的方法对中国特级道砟休止角进行实测所得到的平均值为(39.78±1.27)°。2.以实测结果为目标,采用响应面方法对特级道砟离散元仿真参数进行优选,由方差分析可得2个显著的一次项参数(静摩擦系数和滚动摩擦系数)以及多个显著的多次项参数组合;最优参数组合为:泊松比为0.24,密度为2600 kg/m~3,杨氏模量为5.45×1010 Pa,碰撞恢复系数为0.72,静摩擦系数为0.56,滚动摩擦系数为0.27。3.利用特级道砟离散元最优参数建立了离散元轨排模型,并进行了轨枕横向阻力试验;仿真结果与室内试验实测阻力曲线趋势基本一致,表明响应面法获得的接触参数取值可用于碎石道床相关的离散元仿真。 展开更多
关键词 有砟轨道 道砟 离散元 参数 标定 响应面法
基于减振孔降振及其影响参数数值模拟研究 预览
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作者 沈顺平 《福建建设科技》 2019年第4期50-54,共5页
在地铁爆破施工中,部分线路的周围环境十分复杂,产生爆破振动给周边人员、建(构)筑物、道路等造成影响。本文对减振孔的减振机理和影响参数进行了分析,运用ANSYS/LS-DYNA软件,模拟和分析了减振孔影响参数(如孔径d、深度差值△H、爆心距... 在地铁爆破施工中,部分线路的周围环境十分复杂,产生爆破振动给周边人员、建(构)筑物、道路等造成影响。本文对减振孔的减振机理和影响参数进行了分析,运用ANSYS/LS-DYNA软件,模拟和分析了减振孔影响参数(如孔径d、深度差值△H、爆心距离e、孔距a等)的降振效果,并定量给出了不同参数对降振率影响的一般规律,为今后爆破施工中减振孔参数设计及优化提供参考。 展开更多
关键词 减振孔 减振效果 参数 数值模拟
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出口澳大利亚砂石漏斗车 预览
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作者 王剑 《铁道车辆》 2019年第9期23-24,40,I0001共4页
介绍了出口澳大利亚砂石漏斗车的主要结构、技术参数、计算和试验情况。
关键词 砂石漏斗车 结构 参数 试验
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