期刊文献+
共找到807篇文章
< 1 2 41 >
每页显示 20 50 100
Highly Ordered Thermoplastic Polyurethane/Aramid Nanofiber Conductive Foams Modulated by Kevlar Polyanion for Piezoresistive Sensing and Electromagnetic Interference Shielding 被引量:6
1
作者 Kunpeng Qian Jianyu Zhou +4 位作者 Miao Miao Hongmin Wu Sineenat Thaiboonrod Jianhui Fang Xin Feng 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第6期335-352,共18页
Highly ordered and uniformly porous structure of conductive foams is a vital issue for various functional purposes such as piezoresistive sensing and electromagnetic interference(EMI) shielding. With the aids of Kevla... Highly ordered and uniformly porous structure of conductive foams is a vital issue for various functional purposes such as piezoresistive sensing and electromagnetic interference(EMI) shielding. With the aids of Kevlar polyanionic chains, thermoplastic polyurethane(TPU) foams reinforced by aramid nanofibers(ANF) with adjustable pore-size distribution were successfully obtained via a nonsolvent-induced phase separation. In this regard, the most outstanding result is the in situ formation of ANF in TPU foams after protonation of Kevlar polyanion during the NIPS process. Furthermore, in situ growth of copper nanoparticles(Cu NPs) on TPU/ANF foams was performed according to the electroless deposition by using the tiny amount of pre-blended Ti_(3)C_(2)T_(x) MXene as reducing agents. Particularly, the existence of Cu NPs layers significantly promoted the storage modulus in 2,932% increments, and the well-designed TPU/ANF/Ti_(3)C_(2)T_(x) MXene(PAM-Cu) composite foams showed distinguished compressive cycle stability. Taking virtues of the highly ordered and elastic porous architectures, the PAM-Cu foams were utilized as piezoresistive sensor exhibiting board compressive interval of 0–344.5 kPa(50% strain) with good sensitivity at 0.46 kPa^(-1). Meanwhile,the PAM-Cu foams displayed remarkable EMI shielding effectiveness at 79.09 dB in X band. This work provides an ideal strategy to fabricate highly ordered TPU foams with outstanding elastic recovery and excellent EMI shielding performance, which can be used as a promising candidate in integration of satisfactory piezoresistive sensor and EMI shielding applications for human–machine interfaces. 展开更多
关键词 Highly ordered conductive foams MXene NANofIBER thermoplastic Kevlar polyanion Piezoresistive sensing Electromagnetic interference shielding
下载PDF
Interlingual Interference in the English Language Word Order Structure of Chinese EFL Learners 被引量:1
2
作者 张俊杰 《海外英语》 2020年第14期109-110,共2页
This paper will focus on some common word order errors that Chinese students make.The author will present a body of contrastive material to illustrate what specific word order errors are in collected writing samples o... This paper will focus on some common word order errors that Chinese students make.The author will present a body of contrastive material to illustrate what specific word order errors are in collected writing samples of Chinese students.Then the er⁃rors will be broken down into certain error types and be analyzed in depth.At the end of this paper,each error type occurrence rate will be calculated and the statistics will be represented in a pie chart.The paper finds out interlingual interference leads to these common errors by Chinese English language learners. 展开更多
关键词 interlingual interference English writing word order errors
下载PDF
Third-order ghost interference with thermal light 被引量:1
3
作者 李洪国 张颖涛 +2 位作者 曹德忠 熊俊 汪凯戈 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第12期4510-4515,共6页
A scheme for third-order ghost interference with thermal light is proposed. The visibility and resolution of the interference fringe related to the bandwidth of the spatial frequency spectrum of the source are analyse... A scheme for third-order ghost interference with thermal light is proposed. The visibility and resolution of the interference fringe related to the bandwidth of the spatial frequency spectrum of the source are analysed. The results show that the visibility of the third-order ghost interference fringe is much higher than that of the second-order one. 展开更多
关键词 ghost interference ghost imaging high-order field correlation
下载PDF
Second-order interference of two independent and tunable single-mode continuous-wave lasers 被引量:1
4
作者 刘建彬 卫栋 +5 位作者 陈辉 周宇 郑淮斌 高宏 李福利 徐卓 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第3期194-199,共6页
The second-order temporal interference of two independent single-mode continuous-wave lasers is discussed by em- ploying two-photon interference in Feynman's path integral theory. It is concluded that whether the sec... The second-order temporal interference of two independent single-mode continuous-wave lasers is discussed by em- ploying two-photon interference in Feynman's path integral theory. It is concluded that whether the second-order temporal interference pattern can or cannot be retrieved via two-photon coincidence counting rate is dependent on the resolution time of the detection system and the frequency difference between these two lasers. Two identical and tunable single-mode continuous-wave diode lasers are employed to verify the predictions. These studies are helpful to understand the physics of two-photon interference with photons of different spectra. 展开更多
关键词 second-order temporal beating two-photon interference Feynman's path integral theory
下载PDF
Sustainability Intelligent Evaluation of Regional Microgrid Interconnection System Based on Combination Entropy Weight Rank Order-TOPSIS and NILA-KELM
5
作者 Haichao Wang Yingying Fan +1 位作者 Weigao Meng Qiaoran Yang 《Energy Engineering》 EI 2022年第3期1075-1101,共27页
Sustainability evaluation of regional microgrid interconnection system is conducive to a profound and comprehensive understanding of the impact of interconnection system projects.In order to realize the comprehensive ... Sustainability evaluation of regional microgrid interconnection system is conducive to a profound and comprehensive understanding of the impact of interconnection system projects.In order to realize the comprehensive and scientific intelligent evaluation of the system,this paper proposes an evaluation model based on combination entropy weight rank order-technique for order preference by similarity to an ideal solution(TOPSIS)and Niche Immune Lion Algorithm-Extreme Learning Machine with Kernel(NILAKELM).Firstly,the sustainability evaluation indicator system of the regional microgrid interconnection system is constructed fromfour aspects of economic,environmental,social,and technical characteristics,and the evaluation indicators are explained.Then,the classical evaluationmodel based on TOPSIS is constructed,and the entropy weight method and rank order method(RO)are coupled to obtain the indicator weight.The niche immune algorithm is used to improve the lion algorithm,and the improved lion algorithm is used to optimize the parameters of KELM,and the intelligent evaluation model based on NILA-KELM is obtained to realize fast real-time calculation.Finally,the scientificity and accuracy of themodel proposed in this paper are verified.The model proposed in this paper has the lowest RMSE,MAE and RE values,indicating that its intelligent evaluation results are the most accurate.This study is conducive to the horizontal comparison of the overall performance of regional microgrid interconnection system projects,helps investors to choose the most promising project scheme,and helps the government to find feasible project. 展开更多
关键词 Regional microgrid interconnection system intelligent evaluation of sustainability combination entropy weight rank order TOPSIS NILA KELM
下载PDF
Generation-channel interference of high-order harmonics of an anharmonic oscillator driven by bi-chrime laser fields and its mechanism
6
作者 王黎明 蔡俊 乔豪学 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第7期142-150,共9页
A method to describe the generation channels of high-order harmonics is proposed. According to this method, the mechanism of generation-channel interference of high-order harmonics is revealed clearly. We take the anh... A method to describe the generation channels of high-order harmonics is proposed. According to this method, the mechanism of generation-channel interference of high-order harmonics is revealed clearly. We take the anharmonic oscillator driven by bi-chrome fields as an example to illustrate that this method can be used to understand the effect of generation-channel interference. 展开更多
关键词 generation-channel interference anharmonic oscillator high-order harmonics
下载PDF
Influence of the initial electronic state on minima of high-order harmonic spectrum radiated from hydrogen molecular ion
7
作者 崔会芳 苗向阳 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第10期194-199,共6页
We theoretically investigate the high-order harmonic generation of the one-dimensional hydrogen molecular ion at fixed intermediate internuclear distance, driven by a multicycle laser field. Our results show that the ... We theoretically investigate the high-order harmonic generation of the one-dimensional hydrogen molecular ion at fixed intermediate internuclear distance, driven by a multicycle laser field. Our results show that the initial electronic state of the hydrogen molecular ion affects the modulation of the high-order harmonic spectrum, especially the positions of the minima. Based on the two-state model, the underlying physical mechanism of the minimum is analyzed and discussed. Further analysis shows that the different positions of the minima in the different initial electronic states can be understood via the different interferences of the two phase-adiabatic states at the ionization times. 展开更多
关键词 the minima of the high-order harmonic spectrum interference phase-adiabatic states
下载PDF
The Formation of Fringes of Equal Chromatic Order across Double Clad Fiber in the Presence of High Power Lasers
8
作者 Mona F. Omar Rania H. Abd El-Maksoud 《Optics and Photonics Journal》 2016年第2期29-38,共10页
Multiple-beam fringes of equal chromatic order interferometry is a powerful technique to extract optical properties over a continuous range of spectrum. In this paper we develop a theory for the spectral shape of the ... Multiple-beam fringes of equal chromatic order interferometry is a powerful technique to extract optical properties over a continuous range of spectrum. In this paper we develop a theory for the spectral shape of the fringes of equal chromatic order (FECO) that are formed across a double-clad fiber. The modified single term Sellmeier dispersion formula is used to construct the refractive index dispersion curves for the liquid, claddings, and core. Expressions for the paraxial optical path length for several rays passing through the fiber and the liquid are developed. The condition of bright fringe is applied to get an analytical expression for the spectral shape of the FECO across a double-clad fiber with an elliptical/circular inner cladding. A potential application of this theory is to determine the dispersion of Kerr constant of the claddings and the core of the fiber. To illustrate the theory and its application, simulation examples are provided and discussed. 展开更多
关键词 interference Physical Optics DISPERSION Nonlinear Optics Fringes of Equal Chromatic order Double-Clad Fibers
下载PDF
Third-order optical intensity correlation measurements of pseudo-thermal light
9
作者 陈希浩 吴炜 +1 位作者 孟少英 李明飞 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第9期148-153,共6页
Third-order Hanbrury Brown-Twiss and double-slit interference experiments with a pseudo-thermal light are performed by recording intensities in single, double and triple optical paths, respectively. The experimental r... Third-order Hanbrury Brown-Twiss and double-slit interference experiments with a pseudo-thermal light are performed by recording intensities in single, double and triple optical paths, respectively. The experimental results verifies the theoretical prediction that the indispensable condition for achieving a interference pattern or ghost image in Nth-order intensity correlation measurements is the synchronous detection of the same light field by each reference detector, no matter the intensities recorded in one, or two, or N optical paths. It is shown that, when the reference detectors are scanned in the opposite directions, the visibility and resolution of the third-order spatial correlation function of thermal light is much better than that scanned in the same direction, but it is no use for obtaining the Nth-order interference pattern or ghost image in the thermal Nth-order interference or ghost imaging. 展开更多
关键词 third-order intensity correlation thermal double-slit interference pseudo-thermal light
下载PDF
The Analysis of Strategic Driving Factors of Logistics Cost Based on Fuzzy Multiple-attribute Lattice-order Decision-making Method
10
《成都信息工程学院学报》 2012年第5期511-515,共5页
关键词 最优化 数学 理论 函数
下载PDF
核映射和Rank-Order距离的局部保持投影相似性度量方法 被引量:3
11
作者 秦玉华 张萌 +1 位作者 杨宁 单秋甫 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2021年第10期3117-3122,共6页
针对近红外光谱高维、高冗余、非线性和小样本等特点导致光谱相似性度量时出现的“维度灾难”,提出一种基于核映射和rank-order距离的局部保持投影(KRLPP)算法。首先将光谱数据经过核变换映射到更高维空间,有效保证了流形结构的非线性... 针对近红外光谱高维、高冗余、非线性和小样本等特点导致光谱相似性度量时出现的“维度灾难”,提出一种基于核映射和rank-order距离的局部保持投影(KRLPP)算法。首先将光谱数据经过核变换映射到更高维空间,有效保证了流形结构的非线性特征。然后改进局部保持投影(LPP)算法对数据进行降维操作,将rank-order距离替代传统的欧氏距离或测地线距离,通过共享邻近点的信息,得到更加准确的局部邻域关系。最后在低维空间通过距离的计算实现光谱的度量。该方法不仅有效解决了高维空间存在的“距离失效”问题,同时还提高了相似性度量结果的精度。为了验证KRLPP算法的有效性,首先根据降维前后数据集信息残差的变化确定了最佳参数近邻点的个数k和降维后的维数d。其次,从光谱降维投影效果和模型分类效果两个角度与PCA,LPP和INLPP算法进行了对比,结果表明KRLPP算法对于烟叶的部位有较好的区分能力,降维效果以及对于不同部位的正确识别率明显优于PCA,LPP和INLPP。最后,从某品牌卷烟叶组配方中选取了5个代表性烟叶作为目标烟叶,分别采用PCA,LPP和KRLPP方法从300个用于配方维护的烟叶样品中为每个目标烟叶寻找相似烟叶,并从化学成分和感官评价两方面对替换前后的烟叶及叶组配方进行了评价分析。其中LPP和KRLPP用于降维的参数选择保持一致,PCA选择前6个主成分。结果表明,由KRLPP选出的替换烟叶与替换配方在总糖、还原糖、总烟碱、总氮等化学成分以及香气、烟气、口感等感官指标上较PCA、LPP方法差异最小,相似性度量准确度最高。该方法可应用于配方产品替换原料的查找,辅助企业实现产品质量的维护。 展开更多
关键词 近红外光谱 局部保持投影算法 核映射 rank-order距离 相似性度量
下载PDF
Interference Alignment in Two-Way Relay Networks via Rank Constraints Rank Minimization 被引量:1
12
作者 Xue Jiang Baoyu Zheng Yuelin Du 《China Communications》 SCIE CSCD 2017年第7期195-203,共9页
Interference alignment(IA) is one of the promising measures for the multi-user network to manage interference. The rank constraints rank minimization means that interference spans the lowest dimensional subspace and t... Interference alignment(IA) is one of the promising measures for the multi-user network to manage interference. The rank constraints rank minimization means that interference spans the lowest dimensional subspace and the useful signal spans all available spatial dimensions. In order to improve the performance of two-way relay network, we can use rank constrained rank minimization(RCRM) to solve the IA problem. This paper proposes left reweighted nuclear norm minimization-γalgorithm and selective coupling reweighted nuclear norm minimization algorithm to implement interference alignment in two-way relay networks. The left reweighted nuclear norm minimization-γ algorithm is based on reweighted nuclear norm minimization algorithm and has a novel γ choosing rule. The selective coupling reweighted nuclear norm minimization algorithm weighting methods choose according to singular value of interference matrixes. Simulation results show that the proposed algorithms considerably improve the sum rate performance and achieve the higher average achievable multiplexing gain in two-way relay interference networks. 展开更多
关键词 wireless Communications interference alignment two-way relay networks rank constraints rank minimization
下载PDF
Optimizing Rank of Landscape Planning Works of Urban Wetland Park 被引量:1
13
作者 Qiao Li-fang Zhang Yi-chuan +1 位作者 Qi An-guo Li Xin-zheng 《Journal of Northeast Agricultural University(English Edition)》 CAS 2012年第3期87-91,共5页
Classifying and ranking the huge amounts of landscape planning works of urban wetland park is always difficult due to the multi-functions (ecological, leisure, educational and disaster prevention) of the urban wetla... Classifying and ranking the huge amounts of landscape planning works of urban wetland park is always difficult due to the multi-functions (ecological, leisure, educational and disaster prevention) of the urban wetland park. Therefore, an optimizing rank system is urgently needed. Analytic Hierarchy Process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) models were used to rank the planning works of 30 urban wetland park based on four mainly factors, which included landscape ecological planning, landscape planning, ecological planning and economic planning. The study indicated that the AHP- TOPSIS model had good discrimination in the classification and ranking of landscape planning works of urban wetland park and it was also applicable to the planning works of other urban greenbelts. 展开更多
关键词 landscape planning work optimizing rank urban wetland park Analytic Hierarchy Process (AHP) Technique for order Preference by Similarity to Ideal Solution (TOPSIS)
下载PDF
Weakness Ranking Method for Subsystems of Heavy-Duty Machine Tools Based on FMECA Information 被引量:3
14
作者 Zhaojun Yang Jinyan Guo +3 位作者 Hailong Tian Chuanhai Chen Yongfu Zhu Jia Liu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第1期156-167,共12页
Heavy-duty machine tools are composed of many subsystems with different functions,and their reliability is governed by the reliabilities of these subsystems.It is important to rank the weaknesses of subsystems and ide... Heavy-duty machine tools are composed of many subsystems with different functions,and their reliability is governed by the reliabilities of these subsystems.It is important to rank the weaknesses of subsystems and identify the weakest subsystem to optimize products and improve their reliabilities.However,traditional ranking methods based on failure mode effect and critical analysis(FMECA)does not consider the complex maintenance of products.Herein,a weakness ranking method for the subsystems of heavy-duty machine tools is proposed based on generalized FMECA information.In this method,eight reliability indexes,including maintainability and maintenance cost,are considered in the generalized FMECA information.Subsequently,the cognition best worst method is used to calculate the weight of each screened index,and the weaknesses of the subsystems are ranked using a technique for order preference by similarity to an ideal solution.Finally,based on the failure data collected from certain domestic heavy-duty horizontal lathes,the weakness ranking result of the subsystems is obtained to verify the effectiveness of the proposed method.An improved weakness ranking method that can comprehensively analyze and identify weak subsystems is proposed herein for designing and improving the reliability of complex electromechanical products. 展开更多
关键词 Complex electromechanical products Weakness ranking method Failure mode effect and critical analysis(FMECA) Cognition best worst method(CBWM) Technique for order preference by similarity to an ideal solution(TOPSIS)
下载PDF
Two-center interference in high-harmonic generation of H2%+ in a combination of a mid-infrared laser field and a terahertz field
15
作者 Jun Zhang Xue-Fei Pan +4 位作者 Tong-Tong Xu Hong-Dan Zhang Hui Du Jing Guo Xue-Shen Liu 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第1期176-181,共6页
We theoretically investigate the two-center interference in high-order harmonics generated from the H2-+ in a combination of a mid-infrared laser and a terahertz field by numerically solving the time-dependent Schr &... We theoretically investigate the two-center interference in high-order harmonics generated from the H2-+ in a combination of a mid-infrared laser and a terahertz field by numerically solving the time-dependent Schr ¨odinger equation(TDSE).The interference minima in high-order harmonic generation(HHG) are effectively suppressed when a THz field is added.The contribution to HHG from the two separate nuclei is used to demonstrate the locating order of the harmonic minima.Furthermore, we also investigate the emission time of harmonics. The results show that the intensity of the short path around 60^th order after adding a THz field is stronger than that in the mid-infrared laser field, which further illustrates the suppression of the interference minima in HHG. 展开更多
关键词 terahertz field high-order harmonic two-center interference
下载PDF
Quantum interference of multi-orbital effects in high-harmonic spectra from aligned carbon dioxide and nitrous oxide
16
作者 Hong-Jing Liang Xin Fan +5 位作者 Shuang Feng Li-Yu Shan Qing-Hua Gao Bo Yan Ri Ma Hai-Feng Xu 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第9期27-31,共5页
We investigate experimentally multi-orbital effects in high-order harmonic generation(HHG) from aligned CO2 and N2O molecules by intense femtosecond laser fields with linear and elliptical polarizations.For either of ... We investigate experimentally multi-orbital effects in high-order harmonic generation(HHG) from aligned CO2 and N2O molecules by intense femtosecond laser fields with linear and elliptical polarizations.For either of the aligned molecules, a minimum in the harmonic spectrum is observed, the position of which shifts to lower-order harmonics when decreasing the intensity or increasing the ellipticity of the driving laser.This indicates that the minimum originates from the dynamic interference of different channels, of which the tunneling ionization and recombination are contributed via different molecular orbitals.The results show that both the highest occupied molecular orbital(HOMO) and low-lying HOMO-2 in CO2(or HOMO-1 in N2O) contribute to the molecular HHG in both linearly and elliptically polarized strong laser fields.Our study would pave a way for understanding multi-electron dynamics from polyatomic molecules irradiated by strong laser fields. 展开更多
关键词 high-order HARMONIC generation ALIGNED molecule multi-orbital effect dynamic interference
下载PDF
Probing dynamic interference in high-order harmonic generation from long-range molecular ion:Bohmian trajectory investigation
17
作者 王俊 王兵兵 +5 位作者 郭福明 李苏宇 丁大军 陈基根 曾思良 杨玉军 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第5期233-237,共5页
Using Bohmlan trajectory (151) method, we investigate the dynamic interference in nlgn-orcter narmonlc generauon from diatomic molecular ions. It is demonstrated that the main characteristics of the molecular harmon... Using Bohmlan trajectory (151) method, we investigate the dynamic interference in nlgn-orcter narmonlc generauon from diatomic molecular ions. It is demonstrated that the main characteristics of the molecular harmonic spectrum can be well reproduced by only two BTs which are located at the two ions. This haiapens because these two localized trajectories can receive and store the whole collision information coming from all of the other re-collision trajectories. Therefore, the amplitudes and frequencies of these two trajectories represent the intensity and frequency distribution of the harmonic generation. Moreover, the interference between these two trajectories shows a dip in the harmonic spectrum, which reveals the molecular structure information. 展开更多
关键词 Bohmian trajectory molecular high-order harmonic generation dynamic interference
下载PDF
An analysis of quantitative PCR reliability through replicates using the C_(t)method
18
作者 Chris C.Stowers Frederick R.Haselton Erik M.Boczko 《Journal of Biomedical Science and Engineering》 2010年第5期459-469,共11页
There is considerable interest in quantitatively measuring nucleic acids from single cells to small populations. The most commonly employed laboratory method is the real-time polymerase chain reaction (PCR) analyzed w... There is considerable interest in quantitatively measuring nucleic acids from single cells to small populations. The most commonly employed laboratory method is the real-time polymerase chain reaction (PCR) analyzed with the crossing point or crossing threshold (Ct) method. Utilizing a multiwell plate reader we have performed hundreds of replicate reactions each at a set of initial conditions whose initial number of copies span a concentration range of ten orders of magnitude. The resultant Ct value distributions are analyzed with standard and novel statistical techniques to assess the variability/reliability of the PCR process. Our analysis supports the following conclusions. Given sufficient replicates, the mean and/or median Ct values are statistically distinguishable and can be rank ordered across ten orders of magnitude in initial template concentration. As expected, the variances in the Ct distributions grow as the number of initial copies declines to 1. We demonstrate that these variances are large enough to confound quantitative classi?cation of the initial condition at low template concentrations. The data indicate that a misclassi?cation transition is centered around 3000 initial copies of template DNA and that the transition region correlates with independent data on the thermal wear of the TAQ polymerase enzyme. We provide data that indicate that an alternative endpoint detection strategy based on the theory of well mixing and plate ?lling statistics is accurate below the mis- classi?cation transition where the real time method becomes unreliable. 展开更多
关键词 Misclassification Transition Single Molecule Counting rank ordering Running Title PCR Replicates and Reliability
下载PDF
Comparison of Block Design Nonparametric Subset Selection Rules Based on Alternative Scoring Rules
19
作者 Gary C. McDonald Sajidah Alsaeed 《Applied Mathematics》 2024年第5期355-389,共35页
This article compares the size of selected subsets using nonparametric subset selection rules with two different scoring rules for the observations. The scoring rules are based on the expected values of order statisti... This article compares the size of selected subsets using nonparametric subset selection rules with two different scoring rules for the observations. The scoring rules are based on the expected values of order statistics of the uniform distribution (yielding rank values) and of the normal distribution (yielding normal score values). The comparison is made using state motor vehicle traffic fatality rates, published in a 2016 article, with fifty-one states (including DC as a state) and over a nineteen-year period (1994 through 2012). The earlier study considered four block design selection rules—two for choosing a subset to contain the “best” population (i.e., state with lowest mean fatality rate) and two for the “worst” population (i.e., highest mean rate) with a probability of correct selection chosen to be 0.90. Two selection rules based on normal scores resulted in selected subset sizes substantially smaller than corresponding rules based on ranks (7 vs. 16 and 3 vs. 12). For two other selection rules, the subsets chosen were very close in size (within one). A comparison is also made using state homicide rates, published in a 2022 article, with fifty states and covering eight years. The results are qualitatively the same as those obtained with the motor vehicle traffic fatality rates. 展开更多
关键词 order Statistics rank Scoring Methods Probability of a Correct Selection Subset Size Motor Vehicle Traffic Fatality Rates Homicide Rates Asymptotic Distributions
下载PDF
基于Low rank近似的黏弹性介质衰减补偿微地震逆时定位与裂缝成像 被引量:5
20
作者 唐杰 刘英昌 +1 位作者 李聪 孙成禹 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2021年第8期2858-2876,共19页
真实地下介质具有黏弹性,地震波在传播过程中会发生耗散与频散.忽视黏弹性介质的吸收衰减效应,逆时延拓过程中地震波将会出现振幅减弱、相位失真等现象,无法准确定位震源真实位置,因此需要对黏弹性介质中传播的波场进行衰减补偿,并通过... 真实地下介质具有黏弹性,地震波在传播过程中会发生耗散与频散.忽视黏弹性介质的吸收衰减效应,逆时延拓过程中地震波将会出现振幅减弱、相位失真等现象,无法准确定位震源真实位置,因此需要对黏弹性介质中传播的波场进行衰减补偿,并通过采用合适的成像算子对微地震震源进行定位与裂缝成像.本文基于耗散与频散解耦的分数阶黏弹性波动方程模拟波场,采用low rank分解近似混合域算子,分离衰减相关项并反转耗散项符号,并在补偿的衰减项波场的波数域中进行低通滤波,压制噪声的影响;使用优化后的成像算子进行微地震震源定位,并通过分离散射波场,对散射波进行逆时反传寻找裂缝.数值实验证明,本文方法通过low rank近似有效提高了计算效率,衰减补偿算子在滤波器约束下能够稳定地补偿反向延拓的波场,优化后的成像算子能够在压制随机噪声的同时进一步提高计算效率和定位分辨率. 展开更多
关键词 黏弹性 分数阶 Low rank 衰减补偿 微地震 逆时定位
下载PDF
上一页 1 2 41 下一页 到第
使用帮助 返回顶部