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Urban effects and summer thunderstorms in a tropical cyclone affected situation over Guangzhou city

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Science China Earth Sciences 2007年第12期50卷 1867-1876页

作者： MENG WeiGuang1,3.YAN JingHua1 & HU HaiBo2 1 institute of Tropical and Marine meteorology,Chinese Meteorological Administration(CMA),Guangzhou 510080,China 2 institute of Urban meteorology,CMA,beijing 100089,China 3.State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,beijing 100081,China 1. institute of Tropical and Marine meteorology Chinese Meteorological Administration (CMA) Guangzhou 510080 China 3. State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China 2. institute of Urban meteorology CMA Beijing 100089 China

With data mainly from Guangzhou mesonet Automatic Weather Stations(AWS),Guangzhou Doppler Radar and satellite TBB data,characteristics and evolution of the urban heat island(UHI) over Guang-zhou City were analyzed in a tropical cyclone affected situation for early August *** particular,two thunderstorms occurring during this period respectively at the night of 4 August and in the afternoon of 7 August were investigated to study the relationships between the development of thunderstorms and the *** showed that two thunderstorms were associated with the UHI *** induced local air convergence and initiated the thunderstorm *** cases showed a general agreement in time and space for the locations of maximum UHI,convergence,convection,and *** was found to be more favorable to developing in time periods and locations with stronger intensity of *** also showed that,due to the urban effects,both thunderstorms got strengthened when moving over Guangzhou City,with maximum radar echoes observed right over the urban area and precipitation located within the *** these features reveal that two thunderstorms were urban-induced storms.

关键词： summer thunderstorms, urban heat islands (UHI), urban effects, tropical cyclone

A note on n-edge chromatic number

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Chinese Science Bulletin 1997年第23期42卷 1952-1954页

作者： SUN Liang and ZHANG Zhongfu1. Department of applied Mathematics, beijing institute of Technology, beijing 100081, China 2. institute of applied Mathematics, Lanzhou institute of Railway, Lanzhou 73.070, China Department of applied Mathematics Beijing Institute of Technology Beijing 100081 China

ALL graphs appearing in this note are simple. A graph with p vertices and q edges will becalled a (p, q )-graph. The maximum degree of G is denoted by Δ(G).Let n≥2 be an integer. The n-edge chromatic number X_n (G) of a simple graph G is theminimum cardinality of a set of colors with which one can assign the colors to the edges of Gsuch that the edges on a path of length less than or equal to n receive different *** aim of this note is to explore the bounds for X’_n (G) and X’_n (G) + X’_n (G). It is

关键词： graph complement n-edge chromatic number.

Fractal Structure of the Core Loss Spectrum of Co-based Amorphous Soft Magnetic Alloy with Constant Permeability

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International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 54-56页

作者： Yiping Chen (applied Science School, University of Science and Technology beijing, beijing 100083. China) applied Science School University of Science and Technology Beijing Beijing 100083 China

In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range from 10 kHz to 200 kHz and at Bm = 0. 1 T,the P(f) has the fractal structure P (f) = Po, and with the increasing of induced anisotropy energy Ku, the fractal dimension Dfrises, thus the total power loss at high frequency increases and the frequency characteristic of P(f) becomes worse.

关键词： amorphous soft magnetic alloy constant permeability core loss fractal

GENERAL INTERPOLATION FORMULAS FOR SPACES OF DISCRETE FUNCTIONS WITH NONUNIFORM MESHES

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Journal of Computational Mathematics 1995年第1期13卷 70-93页

作者： Zhou Yu-lin(institute of applied Physics and Computational Mathematics, beijing, China ) 北京应用物理和计算数学所北京

The unequal meshsteps are unavoidable in general for scientific and engineering computations especially in large Scale computations. The analysis of difference schemes with nonuniform meshes is very rare even by use of fully heuristic methods. For the purpose of the systematic and theoretical study of the finite difference method with nonuniform meshes for the problems of partial differential equations, the general interpolation formulas for the spaces of discrete functions of one index with unequal meshsteps are established in the present work. These formulas give the connected relationships among the norms of various types, such as' the sum of powers of discrete values, the discrete maximum modulo, the discrete Holder and Lipschitz coefficients.

关键词： Discrete functions Interpolation Mathematical constants Partial differential equations Difference quotients Real lines Finite difference methods Mathematical theorems Ratios Engineering

A NEW STEP-SIZE SKILL FOR SOLVING A CLASS OF NONLINEAR PROJECTION EQUATIONS

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Journal of Computational Mathematics 1995年第4期13卷 357-368页

作者： D. Sun(institute of applied Mathematics, Academia Sinica, beijing, China) ACAD SINICA INST APPL MATHBEIJING 100080PEOPLES R CHINA

In this paper, a new step-size skill for a projection and contraction method([10]) for linear programming is generalized to an iterative method([22]) for solving nonlinear projection equation. For linear programming, our scheme is the same as that of([10]). For complementarity problem and related problems, we give an improved algorithm by considering the new step-size skill and ALGORITHM B discussed in [22]. Numerical results are provided.

关键词： Math A NEW STEP-SIZE SKILL FOR SOLVING A CLASS OF NONLINEAR PROJECTION EQUATIONS PX STEP

CONSERVATION LAWS OF NONHOLONOMIC NONCONSERVATIVE DYNAMICAL SYSTEMS

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Acta Mechanica Sinica 1989年第2期5卷 167-175页

作者： Liu Duan (Department of applied Mechanics,beijing institute of Technology) 1. Department of applied Mechanics Beijing Institute of Technology Beijing China

In this paper conservation laws of nonholonomic nonconservative dynamical systems are studied by using the differential variational principles of Jourdain and the generalized Noether's identi- ties of nonconservative ... 详细信息

关键词： conservation law nonholonomic constraint Noether's theorem

Solving the input data in error correc-tion of optical fabrication by finite Fourier coefficient algorithm

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Science China(Technological Sciences) 2006年第1期49卷 50-60页

作者： CHENG Haobo1,2, SUN Guozheng3.& FENG Zhijing2 1. Department of Optical Engineering, beijing institute of Technology, beijing 100081, China 2. Department of Precision Instruments and Mechanology, Tsinghua University, beijing 100084, China 3. China North Industries Group Corporation, beijing 100089, China 1. Department of Optical Engineering Beijing Institute of Technology Beijing 100081 China 2. Department of Precision Instruments and Mechanology Tsinghua University Beijing 100084 China 3. China North Industries Group Corporation Beijing 100089 China

A free-form lens (FFL) is a special surface that is difficult to be fabricated. FFL are usually fabricated by computer-controlled optical surfacing (CCOS) technique. During CCOS, the material removal amount is determined by the unit removal function (URF) convoluting with the input data――the dwell time. When the removal amount and the URF are known, how to solve the input data involves the special algorithm――deconvolution. Usually, the input data are solved by virtue of low pass filter or iterative methods. However, an approximation solution would destroy the machining stability nec-essary to perform precisely CCOS. In this paper, to solve the input data, a new method that is based on the finite Fourier coefficient is put forward. It can give a continuous and accurate solution for fabricating choice. Several parameters are simulated, which influ-ence the process of CCOS, and evaluating on the effect of the method is also carried out. Experimental results verify that this method is suitable for guiding the manufacturing of high precision FFL.

关键词： optical fabrication, computer controlled optical surfacing, free-form lens, finite Fourier coefficient, error correction.

Algorithm for Computation of Unstructured Real Stability Radius and Its Applications

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International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 245-250页

作者： Xiaodan Zhang Lequan Min(applied Science School, University of Science and Technology beijing, beijing 100083. China) applied Science School University of Science and Technology Beijing Beijing 100083 China

An algorithm for the computation of the unstructured real stability radius of high dimensional linearsystem is presented. Using the accurate formula of the real stability radius of 2-dimensional system linear systemchecks the algorithm. The result shows that the algorithm is reliable and efficient. As applications, the unstructuredreal stability radii of 2-dimensional Chua's circuit and 3.dimensional piecewise-linear system are calculated, thedynamical orbits of the corresponding perturbed systems are simulated.

关键词： lincar systems stability robustness parameter perturbation computational methods

Final Temperature Prediction Model of Molten Steel in RH-TOP Refining Process for IF Steel Production

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Journal of Iron and Steel Research International 2012年第3期19卷 1-5页

作者： WANG Yu-nan1, BAO Yan-ping1, CUI Heng2, CHEN Bin3. JI Chen-xi3.(1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology beijing, beijing 100083. China 2. Engineering Research institute, University of Science and Technology beijing, beijing 100083. China 3. Shougang Research institute of Technology, beijing 100041, China) [a] State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China [b] Engineering Research institute University of Science and Technology Beijing Beijing 100083 China [c] Shougang Research institute of Technology Beijing 100041 China

In order to precisely control the final temperature of molten steel in RH （Ruhrstahl Heraeus）-TOP blowing refining, the final temperature prediction models of molten steel in RH-TOP blowing refining process for Interstitial Free （IF） steel production were established under the condition of oxygen blowing and non-oxygen blowing respec- tively. The results show that the beginning molten steel temperature of refining and the amount of added scrap were influential factors, the baking temperature in vacuum chamber was a factor that had small influence. When the model was operated, the hitting probability was above 95%（under the condition of both oxygen blowing and non-oxygen blo- wing） of prediction deviation ±10℃. The accuracy is analyzed.

关键词： RH-TOP molten steel temperature prediction model