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Fractal Method for Statistical Analysis Geological Data 被引量:2
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作者 Meng Xianguo Zhao PengdaChina University of Geosciences , Wuhan 430074 《Journal of Earth Science》 SCIE CAS CSCD 1991年第1期114-119,共6页
This paper establishes the phase space in the light of spacial series data , discusses the fractal structure of geological data in terms of correlated functions and studies the chaos of these data . In addition , it i... This paper establishes the phase space in the light of spacial series data , discusses the fractal structure of geological data in terms of correlated functions and studies the chaos of these data . In addition , it introduces the R/S analysis for time series analysis into spacial series to calculate the structural fractal dimensions of ranges and standard deviation for spacial series data -and to establish the fractal dimension matrix and the procedures in plotting the fractal dimension anomaly diagram with vector distances of fractal dimension . At last , it has examples of its application . 展开更多
关键词 geological data fractal method fractal dimension space series r/S analysis .
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Research on nonlinear R/S method and its application in earthquake prediction 被引量:1
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作者 王碧泉 黄汉明 +2 位作者 范洪顺 王春珍 陈佩燕 《Acta Seismologica Sinica(English Edition)》 CSCD 1995年第4期653-658,共6页
ResearchonnonlinearR/SmethodanditspplicationinearthquakepredictionBi-QuanWANG(王碧泉);Han-MingHUANG(黄汉明);Hong-S... ResearchonnonlinearR/SmethodanditspplicationinearthquakepredictionBi-QuanWANG(王碧泉);Han-MingHUANG(黄汉明);Hong-ShunFAN(范洪顺);Chuen... 展开更多
关键词 nonlinear theory fractal dimension earthquake prediction r/S method
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Reduced Differential Transform Method for Solving Nonlinear Biomathematics Models 被引量:4
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作者 K.A.Gepreel A.M.S.Mahdy +1 位作者 M.S.Mohamed A.Al-Amiri 《Computers, Materials & Continua》 SCIE EI 2019年第9期979-994,共16页
In this paper,we study the approximate solutions for some of nonlinear Biomathematics models via the e-epidemic SI1I2R model characterizing the spread of viruses in a computer network and SIR childhood disease model.T... In this paper,we study the approximate solutions for some of nonlinear Biomathematics models via the e-epidemic SI1I2R model characterizing the spread of viruses in a computer network and SIR childhood disease model.The reduced differential transforms method(RDTM)is one of the interesting methods for finding the approximate solutions for nonlinear problems.We apply the RDTM to discuss the analytic approximate solutions to the SI1I2R model for the spread of virus HCV-subtype and SIR childhood disease model.We discuss the numerical results at some special values of parameters in the approximate solutions.We use the computer software package such as Mathematical to find more iteration when calculating the approximate solutions.Graphical results and discussed quantitatively are presented to illustrate behavior of the obtained approximate solutions. 展开更多
关键词 reduced differential transforms method nonlinear biomathematics models SI1I2r model SIr model analytic approximate solutions qualitative analysis stability and equilibrium.
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Preparation of Layered Potassium Titanate Whiskers with Large Length-diameter Ratio by KDC Method 被引量:4
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作者 吉晓莉 WU Shijiang +1 位作者 章嵩 ZHAO Xiujian 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第4期669-673,共5页
Pure K2Ti4O9 whiskers were prepared by KDC(Kneading-Drying-Calcination) method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio(RT/K), calcination temperature(TC) and cooling proces... Pure K2Ti4O9 whiskers were prepared by KDC(Kneading-Drying-Calcination) method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio(RT/K), calcination temperature(TC) and cooling process on phase composition and morphology of the whiskers were investigated by TG-DSC(thermo gravimetric-differential scanning calorimeter), XRD(X-ray diffraction), and SEM(scanning electron microscope). Pure K2Ti4O9 potassium titanate whiskers with large length-diameter ratio(r)(over 250) can be obtained at RT/K = 2.9 and TC = 950 ℃. 展开更多
关键词 KDC(kneading-drying-calcination) method potassium titanate whiskers TiO2/K2CO3 molar ratio(rT/K) length-diameter ratio(r
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云南昭通地区滑坡隐患InSAR广域识别与监测 被引量:5
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作者 张雪 魏云杰 +2 位作者 杨成生 刘勇 杨佳艺 《地球科学与环境学报》 北大核心 2025年第1期128-142,共15页
云南昭通地区位于我国西南山区,受自然条件和人类活动影响,成为我国地质灾害多发地区之一。针对该地区开展滑坡隐患识别与监测对防灾减灾工作具有重要意义。采用R-index方法,分析了升降轨Sentinel-1A数据在该区域进行滑坡隐患识别的适宜... 云南昭通地区位于我国西南山区,受自然条件和人类活动影响,成为我国地质灾害多发地区之一。针对该地区开展滑坡隐患识别与监测对防灾减灾工作具有重要意义。采用R-index方法,分析了升降轨Sentinel-1A数据在该区域进行滑坡隐患识别的适宜性,为后续滑坡识别提供参考;基于干涉图堆叠技术在研究区内共圈定出80处潜在滑坡隐患点,同时选取吉那古滑坡为典型灾害体,在获取升降轨Sentinel-1A数据雷达视线(LOS)向形变速率和形变时间序列的基础上,采用MSBAS InSAR技术获取吉那古滑坡2020~2021年的二维形变结果,并分析其二维时空形变特征。结果表明:2020年1月至2021年12月吉那古滑坡东西向累积形变最高达106.2 mm,垂直向累积形变达-100.3 mm。 展开更多
关键词 INSAr技术 r-index方法 干涉图堆叠技术 多维短基线集技术 适宜性 滑坡 隐患识别 分布规律
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On the Method of Multiplier-enlargement and Approximation of Unbounded Continuous Functions 被引量:1
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作者 郑成德 王仁宏 《Northeastern Mathematical Journal》 CSCD 2001年第2期231-235,共5页
By combining the classical appropriate functions “1, x, x 2” with the method of multiplier enlargement, this paper establishes a theorem to approximate any unbounded continuous functions with modified positive... By combining the classical appropriate functions “1, x, x 2” with the method of multiplier enlargement, this paper establishes a theorem to approximate any unbounded continuous functions with modified positive linear operators. As an example, Hermite Fejér interpolation polynomial operators are analysed and studied, and a general conclusion is obtained. 展开更多
关键词 positive linear operator approximation of unbounded continuous function method of multiplier enlargement Hermite Fejér interpolation polynomial operator
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Numerical stability of solution to delay differential equations under resolvent condition for Runge-Kutta methods
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作者 赵景军 刘明珠 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2001年第2期135-139,共5页
Deals with the application of Kreiss resolvent condition in the error growth analysis of numerical methods, and studies the stability of Runge Kutta method in respect of Kreiss resolvent condition with emphasis on the... Deals with the application of Kreiss resolvent condition in the error growth analysis of numerical methods, and studies the stability of Runge Kutta method in respect of Kreiss resolvent condition with emphasis on the study on the subclass of collocation methods with abscissas in [0,1] by applying the methods to the test equation U′(t)=λU(t)+μU(t-τ)τ>0 with complex constraints μ and λ, and proves under some assumptions on the R K methods that the error growth is uniformly bounded in the stability region. 展开更多
关键词 Delay differential equations STABILITY Kreiss resolvent r K methods
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R/S method for evaluation of pollutant time series in environmental quality assessment
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作者 Bu Quanmin Bi Jun +1 位作者 Yuan Zengwei Huang Lei 《Water Science and Engineering》 EI CAS 2008年第4期82-88,共7页
The significance of the fluctuation and randomness of the time series of each pollutant in environmental quality assessment is described for the first time in this paper. A comparative study was made of three differen... The significance of the fluctuation and randomness of the time series of each pollutant in environmental quality assessment is described for the first time in this paper. A comparative study was made of three different computing methods: the same starting point method, the striding averaging method, and the stagger phase averaging method. All of them can be used to calculate the Hurst index, which quantifies fluctuation and randomness. This study used real water quality data from Shazhu monitoring station on Taihu Lake in Wuxi, Jiangsu Province. The results show that, of the three methods, the stagger phase averaging method is best for calculating the Hurst index of a pollutant time series from the perspective of statistical regularity. 展开更多
关键词 environmental quality assessment time series fractal dimension r/S statistical method Hurst index
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Projected Runge-Kutta methods for constrained Hamiltonian systems 被引量:4
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作者 Yi WEI Zichen DENG +1 位作者 Qingjun LI Bo WANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2016年第8期1077-1094,共18页
Projected Runge-Kutta (R-K) methods for constrained Hamiltonian systems are proposed. Dynamic equations of the systems, which are index-3 differential-algebraic equations (DAEs) in the Heisenberg form, are establi... Projected Runge-Kutta (R-K) methods for constrained Hamiltonian systems are proposed. Dynamic equations of the systems, which are index-3 differential-algebraic equations (DAEs) in the Heisenberg form, are established under the framework of Lagrangian multipliers. R-K methods combined with the technique of projections are then used to solve the DAEs. The basic idea of projections is to eliminate the constraint violations at the position, velocity, and acceleration levels, and to preserve the total energy of constrained Hamiltonian systems by correcting variables of the position, velocity, acceleration, and energy. Numerical results confirm the validity and show the high precision of the proposed method in preserving three levels of constraints and total energy compared with results reported in the literature. 展开更多
关键词 projected runge-Kutta r-K) method differential-algebraic equation(DAE) constrained Hamiltonian system energy and constraint preservation constraint violation
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PVTxSTUDYOFBINARYSYSTEMR22/R152aWITHBURNETTMETHOD
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作者 Su Zhijun Jiang Baocheng Yan Jialu (Shanghai Jiaotong University) (Harbin Institute of Technology) Zhu Mingshan Han Lizhong Fu Yidong (Tsinghua University) 《Journal of Shanghai Jiaotong university(Science)》 EI 1996年第1期7-11,共5页
This paper reports the PVT x properties of R22/R152a system in the ranges of temperature from 298.15K to 353.15K and pressure from 0.288 MPa to 1.288 MPa. Sixty seven PVT x measurements for three compositions, i... This paper reports the PVT x properties of R22/R152a system in the ranges of temperature from 298.15K to 353.15K and pressure from 0.288 MPa to 1.288 MPa. Sixty seven PVT x measurements for three compositions, i.e., 0.2712, 0.4094 and 0.7911 mole fraction of R22, have been measured along 16 isotherms. The uncertainties of temperature and pressure measurements are less than ±0.01K and ±500 Pa respectively. The reliability of the experimental measurements is confirmed by the CSD equation. 展开更多
关键词 PVT x properties r22/r152a BINArY system Burnett method rEFrIGErANT alternatives
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Estimating GARCH Modeling Using Metropolis-Hastings Method in R
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作者 Min Wang Yunshun Wu 《Open Journal of Statistics》 2018年第6期931-938,共8页
This paper mainly talks about a popular approach of volatility of a GARCH-type model in R, while the disturbances are independent and have identical Student-t distribution. It uses the Metropolis-Hastings method to pe... This paper mainly talks about a popular approach of volatility of a GARCH-type model in R, while the disturbances are independent and have identical Student-t distribution. It uses the Metropolis-Hastings method to perform the computations and gives the programs in details in R. 展开更多
关键词 Student’s t Distribution DEGrEE of FrEEDOM GArCH t Model r METrOPOLIS-HASTINGS method
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绿色金融、R&D投入与碳排放的内在关联性研究——基于省际面板数据的实证检验 被引量:2
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作者 刘伟 纪明 +1 位作者 韩进 王竞一 《工业技术经济》 北大核心 2025年第3期45-55,共11页
“碳达峰”和“碳中和”目标下,如何推动中国碳减排与经济绿色低碳转型,已经成为中国高质量发展的重要议题。本文基于2010~2022年我国30个省(区、市)的面板数据,探析了绿色金融和科技研发对碳排放的影响,实证证明了绿色金融与R&D投... “碳达峰”和“碳中和”目标下,如何推动中国碳减排与经济绿色低碳转型,已经成为中国高质量发展的重要议题。本文基于2010~2022年我国30个省(区、市)的面板数据,探析了绿色金融和科技研发对碳排放的影响,实证证明了绿色金融与R&D投入均对碳排放起到显著的抑制作用,而且R&D投入在绿色金融与碳排放之间的起到显著的负向调节作用,它既是绿色金融政策落地的关键驱动力,也是减少碳排放的重要技术手段。因此,我国应当加强绿色金融政策支持、发挥R&D投入和技术创新在实现碳减排中的关键驱动作用,同时推动绿色金融与科技研发协同发展。 展开更多
关键词 绿色金融 科技创新 r&D投入 碳排放 熵权法 单位根检验 区域异质性 科技研发
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P25 Scoring Method for the Assessment of R/C Buildings
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作者 Kubilay Kaptan 《Journal of Civil Engineering and Architecture》 2012年第7期834-843,共10页
An effective rapid assessment technique, called "P25 Scoring Method", has been developed and tested on 26 different case studies recently, in order to predict the collapse vulnerability of the R/C buildings. After a... An effective rapid assessment technique, called "P25 Scoring Method", has been developed and tested on 26 different case studies recently, in order to predict the collapse vulnerability of the R/C buildings. After a short description of the approach, the study presents the sensitivity study of the method to the selected structural parameters by considering incremental deviation of the final scores from the base model. Further, the methodology was applied to an additional 100 damaged buildings in order to check the reliability of the method and some necessary modifications have been applied to the algorithm after considering this larger database. The evaluation of the results has been interpreted as a beneficial guidance for local authorities. The risk bands are defined according to the final scores and the effect of changing the band-width has also been studied through a safe but an economical procedure. A satisfactory correlation of the method with real damage states is obtained and a ready-to-use methodology has been introduced for future studies. 展开更多
关键词 rapid assessment technique P25 scoring method r/C Buildings.
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基于非线性拟合法的GNSS-R风暴潮监测
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作者 张光霁 匡翠林 陈春花 《大地测量与地球动力学》 北大核心 2025年第5期500-505,531,共7页
GNSS-R(global navigation satellite system-reflectometry)技术作为一种有效的海洋潮位监测手段已得到广泛验证,但目前常用的LSP(lomb-scargle periodogram)频谱分析方法在风暴潮监测中仍存在精度和时间分辨率偏低的问题。本文基于中... GNSS-R(global navigation satellite system-reflectometry)技术作为一种有效的海洋潮位监测手段已得到广泛验证,但目前常用的LSP(lomb-scargle periodogram)频谱分析方法在风暴潮监测中仍存在精度和时间分辨率偏低的问题。本文基于中国香港HKQT站点的观测数据,利用非线性拟合法对2018年“山竹”台风风暴潮事件开展反演研究。结合风暴潮期间风速变化数据,对比分析频谱分析法与非线性拟合法的潮位反演性能。结果显示,采用非线性拟合法的测量精度优于8 cm,与验潮站观测数据的相关系数达0.99,相较于频谱分析法潮位表达更光滑连续,有效提高了监测精度和时间分辨率,可为风暴潮灾害监测提供更加可靠的技术支持。 展开更多
关键词 GNSS-r 风暴潮 潮位测量 非线性拟合法
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挤入变挤出?R&D补贴挪用对企业创新绩效的影响效应与作用机制 被引量:3
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作者 刘璐 花昀 李昕 《统计研究》 北大核心 2025年第8期72-83,共12页
以往基于研发(R&D)补贴对企业创新净效应的研究尚未得出一致结论,主要矛盾集中于企业创新是否会因补贴的挤出效应而遭受损失。已有文献多围绕导致挤出效应的客观因素进行讨论,鲜有从企业主观因素出发,研究补贴挪用行为对企业创新的... 以往基于研发(R&D)补贴对企业创新净效应的研究尚未得出一致结论,主要矛盾集中于企业创新是否会因补贴的挤出效应而遭受损失。已有文献多围绕导致挤出效应的客观因素进行讨论,鲜有从企业主观因素出发,研究补贴挪用行为对企业创新的影响。本文使用2007—2023年上市企业数据,采用熵平衡和加权两阶段最小二乘估计方法,对企业存在单方违约情况对研发补贴造成的挤出程度进行研究,为研发补贴的道德风险研究提供一个定量评估机制。研究发现,研发补贴政策对企业创新的激励效果取决于企业是否存在挪用研发补贴的机会主义行为。在挪用行为影响下,政府研发补贴会部分挤出企业的自主研发投入,反之,政府研发补贴对企业研发投入具有杠杆的挤入效应。研发补贴规模、企业创新能力、企业内源资金、企业规模及与政府的联系是影响挪用行为的关键因素。而政府规范财政资金投入监管,加强研发经费投入绩效评价,能有效降低企业单方违约的主观挪用行为,并促进企业创新。本研究丰富了研发补贴挪用行为对企业创新绩效的影响在微观层面的实证证据,为我国研发补贴精准施策提供实证参考。 展开更多
关键词 研发补贴 挪用行为 熵平衡法 挤出效应 挤入效应
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Electron impact excitation of Ni-like gold studied by Dirac R-matrix method
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作者 范全平 汪文慧 +4 位作者 胡峰 曹磊峰 张强强 刘钰薇 蒋刚 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第11期261-267,共7页
We calculate the electron impact excitation of Ni-like gold by using the Dirac R-matrix theory, and the cor- responding collision strengths and effective collision strengths are obtained. In the calculations of the le... We calculate the electron impact excitation of Ni-like gold by using the Dirac R-matrix theory, and the cor- responding collision strengths and effective collision strengths are obtained. In the calculations of the level energy, (1sZ2sZ2p6)3sZ3p63d10, 3s23p63d94/, 3s23p53d104/, and 3s3p63d104/(l = 0, 1,2,3) configurations are included and 107 fine-structure levels are generated. In the calculations of the collision strengths, only the first 59 levels are included. Com- parisons are made with the distorted wave (DW) results of Zeng et al. for both collision strengths and effective collision strengths. For the collision strengths, the two sets of calculations are in excellent agreement for most of the transitions. However, because of the inclusion of the resonances, our effective collision strengths are generally several times larger than those of Zeng et al.. The accuracy of our calculations is assessed. 展开更多
关键词 electron impact excitation r-matrix method Ni-like gold
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Optimization Design of McPherson Suspension Steering System Based on R-W Method
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作者 卞学良 马国清 王志强 《Defence Technology(防务技术)》 SCIE EI CAS 2010年第2期144-149,共6页
The kinematical equations of McPherson suspension and steering system were set up by using R-W method of multi-rigid body system dynamics.The incidence matrix,route matrix,hinge vector matrix and system constraint equ... The kinematical equations of McPherson suspension and steering system were set up by using R-W method of multi-rigid body system dynamics.The incidence matrix,route matrix,hinge vector matrix and system constraint equations were educed.The optimization model of McPherson suspension steering mechanism was founded by regarding the McPherson suspension and steering system as an integrated system.In order to gain the best optimization effect,a continuous weighting function was created according to the requirement of steering system performance.Taking example for TJ7136U,the optimization design of McPherson suspension steering system was conducted in this paper. 展开更多
关键词 MECHANICS r-W method McPherson suspension optimization design weighting function
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阈值效应分析的应用和R软件实现
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作者 盛松 张艳虹 +5 位作者 环璐瑶 郭曼萍 马杭琨 高洪阳 赵阳 黄烨 《中国循证心血管医学杂志》 2025年第2期161-163,174,共4页
当一研究因素超过某一阈值后,其作用大小或/和方向发生显著变化称为阈值效应。阈值效应分析作为一种统计工具,可以推测病变的发生、发展和预后,具有重大意义。目前尚缺乏开源、免费、简便、有效的工具实现阈值效应分析,确定阈值的过程... 当一研究因素超过某一阈值后,其作用大小或/和方向发生显著变化称为阈值效应。阈值效应分析作为一种统计工具,可以推测病变的发生、发展和预后,具有重大意义。目前尚缺乏开源、免费、简便、有效的工具实现阈值效应分析,确定阈值的过程复杂、工作量大,需要较高的编程技巧,因此本文通过实例展示如何通过编写的R脚本文件、精简代码等流程简化这一过程并且降低对编程技巧的要求,使非统计专业人员也能够进行阈值效应分析。首先,通过平滑曲线拟合观察研究因素(X)与结局(Y)间是否存在非线性关系,如果目测存在阈值,采用最大似然法、递归法、分段线性模型和似然比检验确定阈值、阈值前后两段效应量和前后两段的效应量是否显著。 展开更多
关键词 阈值效应 最大似然法 递归法 分段线性回归 r软件
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基于Farneback光流法和U-Net网络的雷达短临降雨预报研究
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作者 张淞淋 柴志勇 李建柱 《水文》 北大核心 2025年第3期1-8,16,共9页
雷达观测的降雨数据相比雨量站观测的降雨数据更能反映降雨的时空分布,对研究流域的产汇流机理、延长洪水预报预见期有重要意义。为研究雷达在流域短临降雨预报的潜力,基于柳林实验流域雷达回波图像数据集,采用Farneback光流法和U-Net... 雷达观测的降雨数据相比雨量站观测的降雨数据更能反映降雨的时空分布,对研究流域的产汇流机理、延长洪水预报预见期有重要意义。为研究雷达在流域短临降雨预报的潜力,基于柳林实验流域雷达回波图像数据集,采用Farneback光流法和U-Net网络模型对雷达回波图像进行不同时间的外推,并基于动态Z-R关系对降雨进行定量估计,将短临降雨预报结果与雨量站实测数据进行对比分析。结果表明:在30 min预见期下,Farneback光流法的预报效果更好,POD达到0.933;而1 h和2 h预见期下,U-Net网络预报效果更佳,POD分别为0.956和0.948。Farneback光流法随着预见期延长,预报效果显著下降,U-Net网络预报效果与预见期关系不密切。 展开更多
关键词 短临降雨预报 雷达回波外推 Farneback光流法 U-Net网络 动态Z-r关系
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Studies on the Synthesis, Growth and Characterization of ([Paranitrophenyl]Imino)Benzene NLO Crystal by Sankaranarayanan-Ramasamy Method
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作者 S. Anbarasu T. Kishore Kumar Prem Anand Devarajan 《Journal of Minerals and Materials Characterization and Engineering》 2013年第3期110-116,共7页
The study of imine-bridged organics has been the hot spot synthesis of second order nonlinear optical (SONLO) and photo-responsive materials in recent years. Herein we present a study of synthesis, growth, and charact... The study of imine-bridged organics has been the hot spot synthesis of second order nonlinear optical (SONLO) and photo-responsive materials in recent years. Herein we present a study of synthesis, growth, and characterization of ([paranitrophenyl]imino)benzene (PNPIB) NLO single crystal. The title compound was synthesized in one step by Schiff base formation. PNPIB single crystal of diameter of 40 mmand length 50 mmwas successfully grown by SR method using a seed as the nucleus. The growth rate formula is derived for the SR method. PNPIB single crystals of 10 mmdiameter and 60 mmheight have been grown at an average growth rate of 3 mmper day from the point seed in a glass crystallizer. Almost 100% stable crystal conversion efficiency was achieved. The as grown PNPIB crystals were characterized using single crystal X-ray diffraction (XRD), X-ray powder diffraction (XRPD), Fourier Transform Infrared (FTIR), Ultraviolet-Visible-Near Infrared (UV-Vis-NIR), 1H & 13C NMR spectral studies, dielectric measurement and NLO studies. Single crystal XRD analysis confirms that the grown ingot belongs to the space group of P2 of monoclinic system thus exhibiting noncentrosymmetric structure. The crystalline perfection was assessed by XRPD. The powder diffraction pattern of the grown crystal has been indexed. The presence of C=N bond with intramolecular hydrogen bonding and the protonation of ions were confirmed by FTIR analysis. The UV-Vis-NIR spectrum of the crystal shows that the crystal has a cut-off at 298 nm. The 1H & 13C NMR spectra confirm the molecular structure. The dielectric behaviour was measured in the frequency range 1 KHz - 10 KHz for the temperature range from 30℃ to 170℃. The slight decrease in dielectric constant has been observed as the frequency is increased and the dielectric loss is very low for the entire frequency range. The second harmonic generation (SHG) in the crystal was observed by Kurtz powder technique. 展开更多
关键词 Single CrYSTAL GrOWTH S-r method Nonlinear Optical Materials
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