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A statistical inference for generalized Rayleigh model under Type-Ⅱ progressive censoring with binomial removals 预览
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作者 REN Junru GUI Wenhao 《系统工程与电子技术:英文版》 SCIE EI CSCD 2020年第1期206-223,共18页
This paper considers the parameters and reliability characteristics estimation problem of the generalized Rayleigh distribution under progressively Type-Ⅱ censoring with random removals,that is,the number of units re... This paper considers the parameters and reliability characteristics estimation problem of the generalized Rayleigh distribution under progressively Type-Ⅱ censoring with random removals,that is,the number of units removed at each failure time follows the binomial distribution.The maximum likelihood estimation and the Bayesian estimation are derived.In the meanwhile,through a great quantity of Monte Carlo simulation experiments we have studied different hyperparameters as well as symmetric and asymmetric loss functions in the Bayesian estimation procedure.A real industrial case is presented to justify and illustrate the proposed methods.We also investigate the expected experimentation time and discuss the influence of the parameters on the termination point to complete the censoring test. 展开更多
关键词 Type-Ⅱprogressive censoring with random removals generalized Rayleigh distribution reliability characteristic maximum likelihood estimation Markov chain Monte Carlo method expected experimentation time
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Spectrum evolution of Rayleigh backscattering in one‐dimensional waveguide 预览
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作者 Fuhui Li Tianyi Lan +3 位作者 Ligang Huang Iroegbu Paul Ikechukwu Wuming Liu Tao Zhu 《光电进展(英文)》 2019年第8期2-8,共7页
Despite the tremendous awareness of Rayleigh scattering characteristics and its considerable research interest for numerous fields,no report has been documented on the dynamic characteristics of spectrum evolution(SpE... Despite the tremendous awareness of Rayleigh scattering characteristics and its considerable research interest for numerous fields,no report has been documented on the dynamic characteristics of spectrum evolution(SpE)and physical law for Rayleigh scattering from a micro perspective.Herein,the dynamic characteristics of the SpE of Rayleigh scattering in a one-dimensional waveguide(ODW)is investigated based on the quantum theory and a SpE-model of Rayleigh backscattering(RBS)source is established.By means of simulation,the evolution law which represents the dynamic process of the spectrum linewidth at a state of continuous scattering is revealed,which is consistent with our previous experimental observation.Moreover,an approximate theoretical prediction of the existing relationship between the spectrum linewidth of RBS source and the transmission length in ODW is proposed,which theoretically provides the feasibility of constructing functional devices suitable to ascertain laser linewidth compression.The designed experimental scheme can be implemented provided the assumptions are fulfilled.In addition,a theoretical model of the micro-cavity structure to realize the deep compression of laser linewidth is proposed. 展开更多
关键词 SCATTERING RAYLEIGH SPECTRUM EVOLUTION LINEWIDTH functional device
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Estimation of Wave Crest Amplitudes Distribution and Freak Wave Occurrence in A Short Crested Mixed Sea 预览
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作者 WANG Ying-guang 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第4期484-492,共9页
In this study we have for the first time proposed a novel transformed linear simulation method for the estimation of wave crest amplitudes distribution and freak wave occurrence in a short crested mixed sea with a bim... In this study we have for the first time proposed a novel transformed linear simulation method for the estimation of wave crest amplitudes distribution and freak wave occurrence in a short crested mixed sea with a bimodal 3D spectrum. For implementing the proposed transformed linear simulation method, a Hermite transformation model expressed in a monotonic cubic polynomial has been constructed so that the first four moments of the original true process match the corresponding moments of the transformed model. The proposed novel simulation method has been applied to forecast the freak wave occurrence in two short crested mixed sea states, one with a directional wave spectrum based on the measured surface elevation data at the coast of Yura, and the other one with a typical directional bimodal Torsethaugen wave spectrum. It is shown in the two cases that the proposed novel simulation method can offer more accurate forecasting results than those obtained from the traditional linear simulation method or by using Rayleigh distribution model. It is also demonstrated in this article that the proposed novel simulation method is more efficient than the nonlinear simulation method. 展开更多
关键词 freak waves short crested MIXED SEA transformed linear simulation RAYLEIGH DISTRIBUTION model
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The Longnan MS5. 5 Earthquake on September 12, 2008:A Very Shallow Event Probably Triggered by the Wenchuan Earthquake 预览
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作者 LUO Xinyu ZENG Xiangfang +3 位作者 DONG Peiyu ZHOU Yong WEI Xing CHENG Huihong 《中国地震研究:英文版》 CSCD 2019年第3期403-417,共15页
The 2008 Wenchuan earthquake has a significant impact on the seismicity of nearby regions. The Longnan earthquake which occurred on September 12,2008 in Gansu Province was out of the aftershock zone. Reliable source p... The 2008 Wenchuan earthquake has a significant impact on the seismicity of nearby regions. The Longnan earthquake which occurred on September 12,2008 in Gansu Province was out of the aftershock zone. Reliable source parameters are essential for understanding the seismogenic process of this earthquake. Therefore,three approaches are adopted to study the source parameters of this event. The focal mechanism is obtained with the g CAP method that takes non-Double-Couple(non-DC)component into account. The two fault planes are NP1:150°/45°/81° and NP2:342°/45°/98°,while the non-DC component is about 53%. The focal depth is 1. 6 km,which indicates the Longnan earthquake is a shallow event. Furthermore,this result is also in good agreement with results obtained with two other approaches:amplitude spectra of Rayleigh wave and surface displacement from In SAR measurement. To analyze the cause of the event,coulomb failure stress change caused by the Wenchuan earthquake on the Longnan earthquake fault plane is calculated. The result shows that coulomb stress change is 30 k Pa around the Longnan earthquake hypocenter,which exceeds the typical triggering threshold of 10 k Pa. The research indicates that the Wenchuan earthquake probably promote the happening of the Longnan earthquake. 展开更多
关键词 Longnan earthquake Source parameter Rayleigh wave amplitude spectra Surface displacement Coulomb failure stress
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Effects of variable viscosity and temperature modulation on linear Rayleigh-Bénard convection in Newtonian dielectric liquid 预览
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作者 P.G.SIDDHESHWAR D.UMA S.BHAVYA 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第11期1601-1614,共14页
The linear Rayleigh-Bénard electro-convective stability of the Newtonian dielectric liquid is determined theoretically subject to the temperature modulation with time.A perturbation method is used to compute the ... The linear Rayleigh-Bénard electro-convective stability of the Newtonian dielectric liquid is determined theoretically subject to the temperature modulation with time.A perturbation method is used to compute the critical Rayleigh number and the wave number.The critical Rayleigh number is calculated as a function of the frequency of modulation,the temperature-dependent variable viscosity,the electric field dependent variable viscosity,the Prandtl number,and the electric Rayleigh number.The effects of all three cases of modulations are established to delay or advance the onset of the convection process.In addition,how the effect of variable viscosity controls the onset of convection is studied. 展开更多
关键词 dielectric liquid TEMPERATURE DEPENDENT VARIABLE VISCOSITY ELECTRIC field DEPENDENT VARIABLE VISCOSITY ELECTRIC Rayleigh number TEMPERATURE modulation
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Dispersion and attenuation of compressional waves in tight oil reservoirs: Experiments and simulations 预览
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作者 Ma Ru-Peng Ba Jing +2 位作者 Carcione José Maria Zhou Xin Li Fan 《应用地球物理:英文版》 SCIE CSCD 2019年第1期33-45,共13页
We performed ultrasonic experiments in specimens from a tight oil reservoir. The P-wave attenuation of fl uid-saturated specimens was estimated by the spectral ratio method. The results suggest that at ultrasonic freq... We performed ultrasonic experiments in specimens from a tight oil reservoir. The P-wave attenuation of fl uid-saturated specimens was estimated by the spectral ratio method. The results suggest that at ultrasonic frequencies, most specimens have stronger attenuation under gas-saturated conditions than at water- or oil-saturated conditions. The P-wave attenuation positively correlates with permeability. Scanning electron microscopy observations and the triple-porosity structure model were used to simulate the wave propagation. The P-wave velocity dispersion and attenuation are discussed on the basis of the Biot, Biot– Rayleigh double-porosity medium, and the triple-porosity structure models. The results suggest that the Biot and Biot–Rayleigh models cannot explain the attenuation, whereas the triple-porosity structure model is in agreement with the experimental data. Furthermore, we infer that microcracks are common in a porosity of 5%–10%, and the size of microcracks increases in samples with higher porosity. However, the volume ratios of microcracks and clay inclusions remain constant regardless of porosity variations. The size of microcracks is signifi cantly larger than the clay inclusions, and the bulk modulus of microcracks is lower than the bulk modulus of clays. 展开更多
关键词 POROSITY Biot RAYLEIGH WAVE DISPERSION ATTENUATION
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On the formation of Basu’s Type Ⅲ(peeled orange) gunshot residues 预览
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作者 Felice Nunziata Matteo Donghi 《Defence Technology(防务技术)》 CAS CSCD 2019年第1期23-26,共4页
In a famous paper published in 1982,a very special class of gunshot residue particles(GSR)was named by Samarendra Basu“peeled orange”,due to their particular structure,consisting of a barium/antimony core covered by... In a famous paper published in 1982,a very special class of gunshot residue particles(GSR)was named by Samarendra Basu“peeled orange”,due to their particular structure,consisting of a barium/antimony core covered by an outer lead leaflet.In this class of GSR particles the surface may show nodular structures of lead.Basu proposed an explanation in terms of a nucleus of antimony and barium that captures lead vapours produced after the explosion of a cartridge into a firearm:as solidification points of antimony and barium are close one another,both higher than solidification point of lead,he stated that lead occurs as a layer around the core in peeled orange GSR particles.In this paper we study the thermodynamic of the barium/antimony alloy and we hypothesize a formation process in terms of colloidal metal growth,charged particles and electrostatic attraction.We propose an updated model of formation for peeled orange GSR particles that explains the existence of outer lead leaflet and nodules in terms of electrostatic attraction of lead nanoparticles and instability of lead droplets. 展开更多
关键词 Peeled ORANGE PARTICLES GSR CDR CHARGED PARTICLES Electrostatic ATTRACTION Rayleigh DROPLET stability
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Trees as large-scale natural phononic crystals: Simulation and experimental verification 预览
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作者 Jiankun Huang Yifan Liu Yaguang Li 《国际水土保持研究(英文)》 2019年第2期196-202,共7页
Urban trees are usually planted on a periodic layout in the spatial configuration.We regard urban trees as large-scale natural phononic crystals.The entire forest is reduced to a reasonable 'tree-soil' unit ce... Urban trees are usually planted on a periodic layout in the spatial configuration.We regard urban trees as large-scale natural phononic crystals.The entire forest is reduced to a reasonable 'tree-soil' unit cell based on the phononic crystal theory and finite element method by COMSOL software is used to obtain the dispersion curves.The Rayleigh wave band gaps of phononic trees are distinguished by the sound cone method.The influences of soil elastic modulus and tree height on band gaps are investigated.A three-dimensional simulation model and experiment test are applied to validate the effect of phononic trees on vibration control.The numerical frequency reduction zones coincide exactly with the theoretical band gaps.Increasing soil stiffness results in a higher-frequency and wider band gap.An increasing tree height is beneficial to obtain low-frequency band gaps.A periodically arranged plantation that Rayleigh wave band gaps at frequency ≤60 Hz could be designed.This study opens up a new theoretical basis for the quantitative analyses of urban trees to the ground vibration mitigation at a certain frequency range. 展开更多
关键词 URBAN trees Phononic crystal DISPERSION CURVE BAND gap RAYLEIGH wave
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Simulation of Natural Convection in a Cavity:Cooling with Top versus Bottom Partition` 预览
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作者 Emel Evren Selamet Ahmet Selamet 《能源与动力工程:英文版》 2019年第9期327-332,共6页
Natural convection in a square cavity is studied numerically with vertical hot walls and a cold partition located at the bottom or top walls. The effect of orientation of partition on isotherms, flow patterns, and hea... Natural convection in a square cavity is studied numerically with vertical hot walls and a cold partition located at the bottom or top walls. The effect of orientation of partition on isotherms, flow patterns, and heat transfer is analyzed for different fluids and Rayleigh numbers. The placement of partition is found to considerably influence the isotherms, flow patterns, and heat transfer. Heat transfer rate is observed always to increase when the partition is moved from bottom to top wall. 展开更多
关键词 Natural convection Rayleigh number Prandtl number
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Effects of Sodium Dodecyl Sulfate on a Single Cavitation Bubble
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作者 王奇 陈伟中 +1 位作者 王寻 赵太阳 《中国物理快报:英文版》 SCIE CAS CSCD 2018年第8期40-43,共4页
关键词 硫酸盐 成穴 RAYLEIGH 动力学模型 起泡 表面活化剂 SDS
A Blind Spectrum Sensing Based on Low-Rank and Sparse Matrix Decomposition 预览
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作者 Junsheng Mu Xiaojun Jing +1 位作者 Hai Huang Ning Gao 《中国通信:英文版》 SCIE CSCD 2018年第8期118-125,共8页
关键词 矩阵分解 GAUSSIAN 白噪音 关键部件 模拟实验 收音机 信号 适用性
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Study of various few-body systems using Gaussian expansion method (GEM)
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作者 Emiko Hiyama Masayasu Kamimura 《物理学前沿:英文版》 SCIE CSCD 2018年第6期49-78,共30页
关键词 GAUSSIAN 身体结构 子系统 宝石 SCHR dinger RAYLEIGH 轻原子核 学习
Phase velocity maps of Rayleigh waves in the Ordos block and adjacent regions
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作者 Shaoxing Hui Wenhua Yan +2 位作者 Yifei Xu Liping Fan Hongwu Feng 《地震学报:英文版》 CSCD 2018年第5期234-241,共8页
We analyze continuous waveform data from 257 broadband stations of the portable seismic array deployed under the 'China Seismic Array-northern part of NS seismic belt' project as well as data from a permanent ... We analyze continuous waveform data from 257 broadband stations of the portable seismic array deployed under the 'China Seismic Array-northern part of NS seismic belt' project as well as data from a permanent seismic network from January 2014 to December 2015. The phase velocity dispersion curve of 7,185 Rayleigh waves is obtained with a method based on the image analysis of phase velocity extraction, and the inversion is obtained. The period of Rayleigh wave phase velocity distribution has a range of 5–40 s, and minimum resolution close to 20 km. The results show that the phase velocity structure image well reflects the geological structural characteristics of the crust and uppermost mantle, and that the phase velocity distribution has obvious lateral heterogeneity. The phase velocity of the 5–15 s period is closely linked to the surface layer and sedimentary layer, the low-velocity anomalies correspond to loose sedimentary cover, and the high-velocity anomalies correspond to orogenic belts and uplifts and the boundary between high and low velocity anomalies is consistent with the block boundary. The phase velocity of the 5–15 s period is strongly affected by the crust layer thickness, the northeastern Tibetan plateau has low-velocity anomalies in the middle to lower crust, the west side of the Ordos block is consistent with the northeastern Tibetan plateau, which may imply the material exchange and fusion in this area. The velocity variation is inversely related to the Moho depth in the 40 s period of Swave, and the lateral velocity heterogeneity represents the lateral variation of the Moho depth. The Ordos block and the northern margin of Sichuan basin are located in the uppermost mantle at this depth, and the depth in the transition zone is still located in the lower crust. 展开更多
关键词 ORDOS block AMBIENT noise tomography RAYLEIGH wave phase velocity
Simulation of the Rayleigh–Benard Convection in a T-Shaped Cavity 预览
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作者 E. Evren Selamet A. Selamet R. Dehner 《能源与动力工程:英文版》 2018年第11期545-552,共8页
Rayleigh-Benard convection driven by the temperature difference between top and bottom surfaces of a T-shaped cavity with two different boundary conditions is studied numerically. Steady or unsteady cellular flow stru... Rayleigh-Benard convection driven by the temperature difference between top and bottom surfaces of a T-shaped cavity with two different boundary conditions is studied numerically. Steady or unsteady cellular flow structures and temperature patterns are illustrated along with the evolution of heat transfer rates (Nusselt number, Nu). The cavity is filled with fluids of various Pr (Prandtl number), including 0.024, 0.71, 6, and 450. The effect of Pr and Ra (Rayleigh number) on the flow regime and heat transfer is established, while comparing the results also with those of the square cavity. 展开更多
关键词 CONVECTION Prandtl NUMBER RAYLEIGH NUMBER INSTABILITY
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The optical/UV excess of X-ray-dim isolated neutron star II. Nonuniformity of plasma on a strangeon star surface
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作者 Wei-Yang Wang Yi Feng +4 位作者 Xiao-Yu Lai Yun-Yang Li Ji-Guang Lu Xuelei Chen Ren-Xin Xu 《天文和天体物理学研究:英文版》 SCIE CAS CSCD 2018年第7期81-92,共12页
关键词 中子星 紫外 孤立 血浆 表面 RAYLEIGH Gaussian 普朗克常数
Error bounds of Lanczos approach for trust-region subproblem
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作者 Leihong ZHANG Weihong YANG +1 位作者 Chungen SHEN Jiang FENG 《中国数学前沿:英文版》 SCIE CSCD 2018年第2期459-481,共23页
因为它在各种各样的应用的信任区域 subproblem (TRS ) 的重要角色,例如在优化并且处于提出病的问题,为解决大规模稀少的 TRS 有几个没有因式分解的算法。截断的 Lanczos 途径由 N.I · M ·古尔德求婚了, S。Lucidi, M。... 因为它在各种各样的应用的信任区域 subproblem (TRS ) 的重要角色,例如在优化并且处于提出病的问题,为解决大规模稀少的 TRS 有几个没有因式分解的算法。截断的 Lanczos 途径由 N.I · M ·古尔德求婚了, S。Lucidi, M。罗马,和 P. L。Toint [暹罗 J。Optim, 1999, 9:504-525 ] 是为对称的线性系统和特征值问题的古典 Lanczos 方法的自然延期并且,确实为特征值计算跟随古典 Rayleigh 夸耀过程。它由 1 组成) 投射原来的 TRS 到 Krylov subspaces 产出更小的尺寸 TRS 然后 2 ) 解决结果的 TRS 得到原来的 TRS 的 approximates。这份报纸论述一个以后的错误为在原来的 TRS 和他们的投射对应物之间的全球最佳的价值和最佳的答案的界限。我们的错误界限主要从 Lanczos 进程以及原来的 TRS 的数据依靠因素并且,能在为截断的 Lanczos 途径设计某些停止的标准有用。 展开更多
关键词 信任 RAYLEIGH 特征值问题 TRS OPTIM 因式分解 线性系统 古尔德
瑞利多普勒激光雷达超窄带滤光器的设计 预览
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作者 李梓霂 陈廷娣 +3 位作者 刘恒嘉 孙东松(导师) 王国成 唐磊 《红外与激光工程》 CSCD 北大核心 2018年第10期78-84,共7页
目前中国科学技术大学车载激光雷达已经实现了对于15~60km中性大气风场的夜间连续观测,鉴于白天观测的信噪比受到背景光的限制,因此,设计了一种利用现有干涉滤光片结合固态FP标准具的超窄带滤光器,用于实现背景噪声的降低。提出了... 目前中国科学技术大学车载激光雷达已经实现了对于15~60km中性大气风场的夜间连续观测,鉴于白天观测的信噪比受到背景光的限制,因此,设计了一种利用现有干涉滤光片结合固态FP标准具的超窄带滤光器,用于实现背景噪声的降低。提出了一种结合鉴频器参数确定FP最佳参数的方法,得出了FP标准具的参数,实现了带宽为8.4pm、中心波长为354.73nm、自由光谱间距为150pm、峰值透过率高于0.67的滤光器,将背景噪声降低到原来的十八分之一。该滤光器有效提高了系统信噪比,减小了风速误差,同时计算了温度、角度变化对滤光器带宽、中心波长和透过率的影响,设计了一种角度调谐的方法。实验结果与理论值具有较高的一致性。 展开更多
关键词 激光雷达 超窄带 瑞利 多普勒 法布里-珀罗标准具
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Weakly Nonlinear Rayleigh–Taylor Instability in Cylindrically Convergent Geometry
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作者 郭宏宇 王立锋 +2 位作者 叶文华 吴俊峰 张维岩 《中国物理快报:英文版》 SCIE CAS CSCD 2018年第5期65-68,共4页
关键词 RAYLEIGH 弱非线性 不稳定性 几何学 会聚 圆柱 泰勒 模式数
轴流转桨式水轮机的湍流数值模拟——水轮机性能预测准确性评估
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作者 PKo(日) 郭全宝 《国外大电机》 2018年第2期52-59,共8页
对轴流转桨式(卡普兰)水轮机空化和压力脉动等流态现象进行深入了解并准确预测,可以设计出使用寿命更长和效率更高的高性能水轮机。在本文中,提出了一种基于轴流转桨式水轮机全流道的高精度水轮机效率和水轮机空化性能预测方法并进... 对轴流转桨式(卡普兰)水轮机空化和压力脉动等流态现象进行深入了解并准确预测,可以设计出使用寿命更长和效率更高的高性能水轮机。在本文中,提出了一种基于轴流转桨式水轮机全流道的高精度水轮机效率和水轮机空化性能预测方法并进行评估。用基于雷诺平均纳维叶.斯托克斯(Reynolds-Averaged Navier-Stokes)方程的流体体积法跟踪自由表面并结合雷诺应力湍流模型对两相流流场进行预测,空化气泡的发胀和溃灭由修正的Rayleigh.Plesset方程进行建模,将预测结果与Ns400轴流转桨式水轮机模型的试验结果进行比较并评估预测的准确性。预测结果与包括水轮机效率,空化性能和压力脉动等试验数据进行比较,预测结果非常准确。此外,还讨论了转轮桨叶表面气穴现象对流道水力损失的影响。为了更好的设计和研究轴流转桨式水轮机,还介绍了水轮机流量和水轮机性能的预测方法并进行评估。 展开更多
关键词 轴流转桨式水轮机 性能预测 湍流数值模拟 评估 RAYLEIGH 水轮机空化 水轮机效率 set方程
分布式多参数光纤传感技术研究进展 预览 被引量:1
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作者 况洋 吴昊庭 +7 位作者 张敬栋 周欢 郑华 黄礼刚 白永忠 屈定荣 邱枫 朱涛 《光电工程》 CSCD 北大核心 2018年第9期62-77,共16页
分布式光纤传感系统利用光纤既能传感又能传输信号的特性实现对光纤沿线振动、应变、温度等物理量的长距离连续测量,在周界安防、电网管道监控、大型结构健康监测等领域具有十分广阔的应用前景。上述的实际应用中,事件或故障的发生通常... 分布式光纤传感系统利用光纤既能传感又能传输信号的特性实现对光纤沿线振动、应变、温度等物理量的长距离连续测量,在周界安防、电网管道监控、大型结构健康监测等领域具有十分广阔的应用前景。上述的实际应用中,事件或故障的发生通常表现为振动、应变以及温度等物理量的改变,振动的探测频响高低、应变探测的动态响应能力以及多参数的同时测量都会影响事件的定位或预警。因此,振动的宽频测量、应变的动态测量以及多参数测量,对事件定位和信息完整捕获起着至关重要的作用,能够推动分布式光纤传感的应用发展。本文介绍了近年来在分布式光纤传感系统中,基于瑞利散射的宽频振动测量、基于布里渊散射的应变动态测量以及基于多散射的多参数测量取得的研究进展。 展开更多
关键词 分布式光纤传感 多参数测量 瑞利 布里渊 拉曼
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