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Chinese Annals of Mathematics,Series B 1991年第1期12卷 13-25页

作者：林龙威 Department of Mathematics Zhongshan UniversityGuangzhouGuangdongChina.

Consider Riemann problem(E),(R)under the condition(M).It is proved that,as0 详细信息

Consider Riemann problem(E),(R)under the condition(M).It is proved that,as0

关键词： Riemann breakdown sufficiently proof vertex 切二成子 inequal implies belongs

An adaptive spatial clustering method for automatic brain MR image segmentation

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Progress in Natural Science:Materials International 2009年第10期19卷 1373-1382页

作者： Jingdan Zhang,Daoqing Dai Center for Computer Vision and Department of Mathematics,Sun Yat-Sen(zhongshan) university,Guangzhou 510275,China Center for Computer Vision and Department of Mathematics Sun Yat-Sen (Zhongshan) University Guangzhou 510275 China

In this paper,an adaptive spatial clustering method is presented for automatic brain MR image segmentation,which is based on a competitive learning algorithm-self-organizing map(SOM).We use a pattern recognition approach in terms of feature generation and classifier ***,a multi-dimensional feature vector is constructed using local spatial ***,an adaptive spatial growing hierarchical SOM(ASGHSOM) is proposed as the classifier,which is an extension of SOM,fusing multi-scale segmentation with the competitive learning clustering algorithm to overcome the problem of overlapping grey-scale intensities on boundary ***,an adaptive spatial distance is integrated with ASGHSOM,in which local spatial information is considered in the clustering process to reduce the noise effiect and the classification *** proposed method is validated by extensive experiments using both simulated and real MR data with varying noise level,and is compared with the state-of-the-art algorithms.

关键词： Self-organizing map Growing hierarchical SOM Adaptive spatial distance Image segmentation MR images

The Effect of Jump on Evaluating Natural Resource Investments

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Chinese Journal of Population,Resources and Environment 2004年第4期2卷 28-32页

作者： Yang Haisheng, Zhou Yongzhang, Wang Shugong Center for Earth Environment & Resources, zhongshan university, Guangzhou 510275, China Institute of Environmental Science, zhongshan university, Guangzhou 510275, China Center for Earth Environment and Resources Zhongshan University Guangzhou 510275 China Institute of Environmental Science Zhongshan University Guangzhou 510275 China

The evaluation of mining and other natural resource projects is made particularly difficult by the high degree of uncertainty attaching to output prices. It is shown that the techniques of continuous time arbitrage and stochastic control theory may be used not only to value such projects but also to determine the optimal policies for developing managing. This paper describes a model for evaluating natural resource investments under uncertainty from a new perspective. The previous works in this field mostly regard the movements of natural resource prices as a continuous GBM process, which pays few attentions to the shock of unexpected bad news. Our model provides the first theoretical method to analyze the impact of such 'jump' on investment decisions. It concludes that the more frequently bad news happens, the earlier a project will be invested.

关键词： Investment Uncertainty Natural resource Stochastic process

Population-size-dependent branching processes in Markovian random environments

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Chinese Science Bulletin 1998年第8期43卷 635-638页

作者： WANG Hanxing 1 and DAI Yonglong 2 1. Department of Mathematics, Shanghai university, Shanghai 201800, China 2. Department of Mathematics, zhongshan university, Guangzhou 510275, China Department of Mathematics Shanghai University Shanghai China Department of Mathematics Zhongshan University Gunngzhou China

A branching model {Z n} n≥0is considered where the offspring distribution of the population’s evolution is not only dependent on the population size, but also controlled by a Markovian environmental process {ξ n} n≥0. For this model, asymptotic behaviour is studied such as limn→∞Z n and limn→∞Z n/m n in the case that the mean m k, θof the offspring distribution converges to m>1 as the population size k grows to ∞. In the case that {ξ n} n≥0is an irreducible positive recurrent Markov chain, certain extinction (i.e. P(Z n=0 for some n)=1) and noncertain extinction (i.e. P(Z n=0 for some n)<1) are studied.

关键词： Markov chains in random environments stochastic population models branching processes.

TRANSFORMATION CHARACTERISTIC OF TWO WAY SHAPE MEMORY MATERIAL CONSTRAINED BY STRESS

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Acta Metallurgica Sinica(English Letters) 1990年第3期3卷 164-169页

作者： LIN Guangming HUANG Yuanshi ZHANG Jinxiu zhongshan university,Guangzhou,China LIN Guangming,Associate Professor,Dept.of Physics,zhongshan university,Guangzhou 510275,China

The snap-acting transition and two way shape memory (TWSM) effect have been obtained in a TWSM spring made of Ni51Ti49 alloy using the constrained effect of stress on driving force of TWSM *** the snap-acting transition has been realized:M_s= M_f and A_s=A_f;hysteresis is rectangular,the height (TWSM effect) and width (hysteresis) of the rectangle can be readjusted by means of constrained *** results of resistance measurments show that,the snap-acting TWSM effect mentioned above was supplied mainly from the transformation of P←→*** thermodynamic model has also been proposed to ac- count for the snap-acting transformation.

关键词： transformation thermodynamics snap action transformation snap action device two way shape memory effect

Water quality modelling of Dapeng Bay, China

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Journal of Environmental Sciences 1989年第2期1卷 76-80页

作者： Zhan Xiaoyong Institute of Environmental Science,zhongshan university,Guangzhou,China

A two-dimensional finite difference Alternating Direction Implicit (ADI) schematic numerical model to solve the vertically intergrated form of the convective-diffusion equation has been developed for description of water quality in Dapeng Bay of China. Computer software for the modelling is well designed to reduce costs of computation and storage. The results agree quite well with the observations available. Organic pollution in Dapeng Bay is discussed based on the computation and observation. Environmental problems relevant to the industrial enterprises along the coast of the bay are also mentioned briefly.

关键词： quality numerical modelling Dapeng Bay organic pollution.

ON THE INTERACTIVE FUNCTIONS OF TAG QUESTIONS

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Chinese Journal of Applied Linguistics 2000年第4期23卷 59-64页

作者： Zhang Yanmei zhongshan university

Tag questions are a distinctive feature in spokenEnglish,but seldom used by the non-native *** show that tags are employed by native speakersmainly to express their interactive and *** this paper,the writer explores the natureof tag questions,mainly their interactive and inter-personal functions in daily *** made with regard to the teaching of tags in theclassroom.

关键词： ON THE INTERACTIVE FUNCTIONS OF TAG QUESTIONS oral TAG

Synthesis of Syndiotactic Polystyrene with Novel Titanocene Catalysts Activated by Modified Methylaluminoxane

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Chinese Chemical Letters 1999年第2期10卷 171-174页

作者： Fang Ming ZHU Qun Fang WANG Yu Tang FANG Shang An LIN(Institute of Polymer Science, zhongshan university. Guangzhou 510275) Institute of Polymer Science Zhongshan University Guangzhou 510275 China

Novel highly active eta(5)-pentamethylcyclopentadienyltribenzyloxy titanium catalyst activated by modified methylaluminoxane (m-MAO) was prepared for styrene syndiospecific polymerization. The influences of the contents of trimethylaluminum (TMA) in m-MAO and external addition of tri-isobutylaluminum (TIBA) on the distribution of the oxidation states of titanium were investigated in detail. The Ti (III) is in favour of styrene syndiospecific polymerization in higher catalytic activity.

关键词： metallocene syndiotactic polystyrene methylaluminoxane

Periodic Number for Anosov Maps

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Acta Mathematica Sinica,English Series 1997年第2期13卷 169-174页

作者： Sun Wenxiang (Department of Computer Science,zhongshan university,Guangzhou 510275,China) 中山大学计算机系广东广州

Let X be a compact metric space and let f:X→X be an Anosov map,i.e.,an expansive selfmap with the pseudoorbit tracing property(***)(see Lemma 1).If Nn(f) denotes the number of fixed points of f^n which we name here the n-periodic number then we prove in the case as n tends to infinity that n^M ≤N_n(f)≤H^n,where M and H are two positive integers.

关键词： Specification property POTP Anosov map

STUDY ON CO-ELECTRODEPOSITION OF Bi-Fe ALLOY FILMS IN ORGANIC BATH

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Acta Metallurgica Sinica(English Letters) 2003年第6期16卷 507-512页

作者： G.R. Li, Y.X. Tong and G.K. LiuSchool of Chemistry and Chemical Engineering, zhongshan university, Guangzhou 510275, China Sch. of Chem. and Chem. Eng. Zhongshan Univ. Guangzhou 510275 China

The cyclic voltametry and potentiostatic electrolysis was used to investigate the preparation of Bi-Fe alloy films in LiClO4-DMSO (dimethylsulfoxide) system. The effects of several factors including the potential of deposition, current density and concentration of iron and bismuth in the solution on the Fe content in the alloy deposits were studied. Experimental results indicated that the amorphous alloy films of Bi-Fe containing Fe 4.40wt%-33.67wt% could be prepared by controlling the system composition and deposition conditions. They were gray, uniform, metallic luster and adhered firmly to the copper substrates analyzed by EDS, SEM and XRD. After heat treatment of crystallization at 270℃ for 1h, the crystal phase of Bi-Fe can be found in XRD patterns.

关键词： bismuth Bi-Fe alloy film electrodeposition DMSO (dimethyl-sulfoxide)