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The total flow control equations and the characteristics of unsteady gradually varied flow in open channels

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Journal of Hydrodynamics 2019年第1期31卷 177-185页

作者： shi-he Liu Qian-yi Zhao Qiu-shi luo State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Yellow River Engineering Consulting Co. LtdZhengzhou 450003China

Most unsteady channel flows in nature and practical engineering appear as gradually varied ones,and in the free surface,the deformation conforms to the long wave ***-dimensional total flow models were usually used to for the numerical simulation of long-term and long-distance reaches to describe the water movements,however,the models lack a clear relationship between the three-dimensional flow field and the total flow ***,few studies of the variations of the roughness coefficient against the time in unsteady flows were *** following results are obtained through the theoretical analysis and the numerical simulations in this paper.(1) One-dimensional total flow control equations of the unsteady gradually varied flow in open channels are obtained directly from the mathematical model of the viscous fluid motion,and can both reflect the influence of the turbulence and provide an explicit expression of the energy slope *** equations establish a direct connection between the descriptions of the three-dimensional flow fields and the one-dimensional total flows.(2) Synchronous prototype observation data and planar two-dimensional numerical simulation results are used to extract the one-dimensional total flow information and discuss the total flow characteristics.(3)The orders of magnitude for terms in the total flow motion equation are compared,and the variation of the roughness coefficient against the time is analyzed.

关键词： Open channel unsteady flow total flow characteristics control equations

SIMULATION OF LOW-CONCENTRATION SEDIMENT-LADEN FLOW BASED ON TWO-PHASE FLOW THEORY

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Journal of Hydrodynamics 2007年第5期19卷 653-660页

作者： LIU shi-he ZHAO shi-lai luo Qiu-shi School of Water Resource and Hydropower Wuhan University Wuhan 430072 China

Low concentration sediment-laden flow is usually involved in water conservancy, environmental protection, navigation and so on. In this article, a mathematical model for low-concentration sediment-laden flow was suggested based on the two-phase flow theory, and a solving scheme for the mathematical model in curvilinear grids was worked out. The observed data in the Zhang River in China was used for the ver/fication of the model, and the calculated results of the water level, velocity and river bed deformation are in agreement with the observed ones.

关键词： two-phase flow sediment-laden flow,numerical simulation

SIMULATION OF SEDIMENT-LADEN FLOW BY DEPTH-AVERAGED MODEL BASED ON UNSTRUCTURED COLLOCATED GRID

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Journal of Hydrodynamics 2007年第4期19卷 525-532页

作者： LIU shi-he luo Qiu-shi MEI Jun-ya School of Water Resource and Hydropower Wuhan University Wuhan 430072 China

The 2-D depth-averaged mathematical model for sediment-laden flows has been widely used in river control and other related engineering problems, and now it is usually solved on structured grids. Since the natural river is usually very complicated in plane boundary, and unstructured grids are more attractive in solving the problems with complicated domains, the following questions about solving 2-D depth-averaged model were discussed in this article：（1） a modified Bowyer algorithm was suggested to generate unstructured grids for natural rivers, （2） the Finite Volume Method （FVM） is employed to discretize the governing equations of the 2-D depth-averaged model and an implicit scheme was suggested with unstructured collocated grids, （3） the observed hydrological data of the Chenglingji Reach in the Yangtze River are used for verification of the presented method It seems that the suggested numerical scheme works very well, and the simulation results of both hydraulic characteristics and river bed deformation are in good agreement with the observed ones.

关键词： Bowyer algorithm unstructured grid SIMPLE algorithm

A Novel Technology for Preparation of High Performance Fiber by Radio Frequency Heating CVD

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Journal of Materials Science & Technology 2000年第6期16卷 637-638页

作者： Nanlin shi, Kun luo Chinese Acad Sci Inst Met Res Shenyang 110015 Peoples R China

In this paper, radio frequency (r.f.) heating CVD technology for preparation of high performance fiber has been introduced. SiC, B fibers have been produced by this technology.

关键词： A Novel Technology for Preparation of High Performance Fiber by Radio Frequency Heating CVD Radio

Gauss Sum of Index 4:(1)Cyclic Case

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Acta Mathematica Sinica,English Series 2005年第6期21卷 1425-1434页

作者： Ke Qin FENG Jing YANG shi Xin luo Department of Mathematical Science Tsinghua University Beijing 100084 P. R. China

Let p be a prime, m ≥ 2, and （m,p（p - 1）） = 1. In this paper, we will calculate explicitly the Gauss sum G（X） = ∑x∈F＊qX（x）ζ^Tp^（x） in the case of [（Z/mZ）＊：（p）] = 4, and -1 （不属于）（p）, wher... 详细信息

Let p be a prime, m ≥ 2, and （m,p（p - 1）） = 1. In this paper, we will calculate explicitly the Gauss sum G（X） = ∑x∈F＊qX（x）ζ^Tp^（x） in the case of [（Z/mZ）＊：（p）] = 4, and -1 （不属于）（p）, where q P^f, f =φ（m）/4, X is a multiplicative character of Fq with order m, and T is the trace map for Fq/Fp. Under the assumptions [（Z/mZ）＊：（p）] = 4 and 1（不属于）（p）, the decomposition field of p in the cyclotomic field Q（ζm） is an imaginary quartic （abelian） field. And G（X） is an integer in K. We deal with the case where K is cyclic in this oaDer and leave the non-cvclic case to the next paper.

关键词： Gauss sum Stickelberger theorem Davenport-Hasse formula cyclic quartic number field

Gauss Sum of Index 4:(2)Non-cyclic Case

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Acta Mathematica Sinica,English Series 2006年第3期22卷 833-844页

作者： Jing YANG shi Xin luo Ke Qin FENG Department of Mathematical Science Tsinghua University

Assume that m ≥ 2, p is a prime number, （m,p（p - 1）） = 1,-1 not belong to 〈p〉 belong to （Z/mZ）^＊ and [（Z/mZ）^＊：〈p〉]=*** this paper, we calculate the value of Gauss sum G（X）=∑x∈F^＊x（x）ζp^T（x） over Fq,where q=p^f,f=φ（m）/4,x is a multiplicative character of Fq and T is the trace map from Fq to *** our assumptions,G（x） belongs to the decomposition field K of p in Q（ζm） and K is an imaginary quartic abelian unmber *** the Galois group Gal（K/Q） is cyclic,we have studied this cyclic case in anotyer paper：＂Gauss sums of index four：（1）cyclic case＂（accepted by Acta Mathematica Sinica,2003）.In this paper we deal with the non-cyclic case.

关键词： Gauss sum Stickelberger Theorem Davenport-Hawse formula class number of imaginary quadratic field

A Mechanism Study of a Novel Acid-Activatable Michael-Type Fluorescent Probe for Thiols

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Chinese Journal of Chemical Physics 2015年第3期28卷 277-287,I0001页

作者： Yao Tong Chun-guang Dai Yi Ren shi-wei luo Department of Chemistry University of Science and Technology of China Hefei 230026 China College of Chemistry and State Key Laboratory of Biotherapy Sichuan University Chengdu 610064 China

A Michael addition is usually taken as a base-catalysed reaction. However, our synthesized 2-（quinolin-2-ylmethylene） malonic acid （QMA） as a Michael-type thiol fluorescent probe is acid-active in its sensing reaction. In this work, based on theoretic calculation and experimental study on 7-hydroxy-2-（quinolin-2-ylmethylene） malonic acid, we demonstrated that QMA as a Michael acceptor is acid-activatable, i.e., it works only in solutions at pH〈7, and the lower the pH of solutions is, the higher reactivity QMA has. In alkaline solution, the malonate QMA[-2H＋]2- cannot react with both RSand RSH. In contrast, 2-（quinolin-2- ylmethylene） malonic ester （QME）, the ester of QMA, reveal a contrary pH effect on its sensing reaction, that is, it can sense thiols in alkaline solutions but not in acidic solutions, like a normal base-catalysed Michael addition. The values of activation enthalpies from theoretic calculation support the above sensing behavior of two probes under different pH conditions. In acidic solutions, the protonated QMA is more highly reactive towards electrophilic attack over its other ionized states in neutral and alkaline solutions, and so can react with lowly reactive RSH. In contrast, there is a big energy barrier in the interaction of QME with RSH （acidic solutions）, and the reaction of QME with the highly reactive nucleophile RS- is a low activation energy process （in alkaline solutions）. Theoretic calculation reveals that the sensing reaction of QMA undergoes a 1,4-addition process with neutral thiols （RSH）, and a 1,2-addition pathway for the sensing reaction of QME with RS-. Therefore, the sensing reaction of QMA is an acid-catalysed Michael addition via a 1,4-addition, and a normal base-catalysed Michael addition via a 1,2-addition.

关键词： Fluorescent probe Thiols Michael addition DFT calculation Transitionstate Activation enthalpy

Robust cubature Kalman filter method for the nonlinear alignment of SINS

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Defence Technology（防务技术） 2021年第2期17卷 593-598页

作者： shi-luo Guo Ying-jie Sun Li-min Chang Yang Li Department of Instrument Electric Aviation University Air ForceChangchunPeople’s Republic of China

Nonlinear initial alignment is a significant research topic for strapdown inertial navigation system(SINS).Cubature Kalman filter(CKF)is a popular tool for nonlinear initial *** CKF assumes that the statics of the observation noise are pre-given before the filtering ***,any unpredicted outliers in observation noise will decrease the stability of the *** view of this problem,improved CKF method with robustness is *** fading factors are introduced to rescale the observation noise *** the update stage of the filter can be autonomously tuned,and if there are outliers exist in the observations,the update should be less *** the Gaussian assumption of KF,the Mahalanobis distance of the innovation vector is supposed to be Chi-square *** a judging index based on Chi-square test is designed to detect the noise outliers,determining whether the fading tune are *** proposed method is applied in the nonlinear alignment of SINS,and vehicle experiment proves the effective of the proposed method.

关键词： SINS Nonlinear alignment Cubature Kalman filter Robust Multiple fading factors Hypothesis test

Identification of LPV system using locally weighted technique

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Applied Mathematics(A Journal of Chinese Universities) 2010年第4期25卷 411-419页

作者： ZENG Jiu-sun GAO Chuan-hou luo shi-hua Department of Mathematics Zhejiang University Hangzhou 310027 China School of Management Jiangxi University of Finance and Economics Nanchang 331300 China

The problem of linear parameter varying （LPV） system identification is considered based on the locally weighted technique which provides estimation of the LPV model parameters at each distinct data time point by giving large weights to measurements that are ＂close＂ to the current time point and small weights to measurements ＂far＂ from the current time point. Issues such as choice of distance function, weighting function and bandwidth selection are discussed. The developed method is easy to implement and simulation results illustrate its efficiency.

关键词： Linear parameter varying system locally weighted technique identification.