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25 June 2004, Volume 2004 Issue 2 Previous Issue    Next Issue

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The Order of A Root of xp-x-1 over Fp SHI Jian-yi;WANG Zhen-hua 2004, 2004 (2):  1-4,23.  Abstract ( 2557 )   Save The present paper is concerned with the order o(αp) of a root αp of the polynomial xp-x-1 over a prime field Fp. We propose a conjecture that o(αp)=mp:=(pp-1)/(p-1) for any prime p. Then we introduce two methods to verify the conjecture in certain cases. Related Articles | Metrics

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C*-Algebras of Tracial Real Rank Zero YAO Hong-liang;;HU Shan-wen 2004, 2004 (2):  5-12.  Abstract ( 2870 )   Save In this paper, we introduce a class of C*-algebras which have tracially real rank zero. We show that if A is a unital C*-algebra with tracial real rank zero and B is a AF-algebra, then A×B has tracial real rank zero. If a unital simple C*-algebra has tracially real rank zero, then it has real rank zero. Related Articles | Metrics

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The Modifications of Trees and the Laplacian Spectrum YUAN Xi-ying;;WU Bao-feng;;XIAO En-li 2004, 2004 (2):  13-18.  Abstract ( 2893 )   Save In the first two parts of this paper, we investigate two kinds of modifications and their relations with the Laplacian spectrum of trees, then give an order of trees which have smaller Laplacian spectra radius. Related Articles | Metrics

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The Energy Growth Property for p-Harmonic Maps LIU Jian-cheng;LIAO Cai-sheng 2004, 2004 (2):  19-23.  Abstract ( 2626 )   Save In this paper, we study the p-energy growth property for a large class of p-harmonic maps. Using Hessian comparison theorem in Riemannian geometry, we obtain the special estimation of p-energy growth. Related Articles | Metrics

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An Optimal Poincaré Inequality LIU Yong-ming;LI Na 2004, 2004 (2):  24-30.  Abstract ( 3367 )   Save Poincaré integral inequality plays an inportant role in the nonlinear stability theorem of Arnold. In this paper, a best possible Poincaré integral inequality is obtained, which can be used to get a better estimation of disturbance bound for two-dimensional quasi-geostrophic flow and a better nonlinear stability criterion as well. Related Articles | Metrics

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Comparison of MINQUE and Simple Estimators under Entropy and Symmetry Loss Functions Abdul-Hussein Saber AL-MOUEL 2004, 2004 (2):  31-36,5.  Abstract ( 3254 )   Save This paper considers comparison of MINQUE and simple estimator of Σ in the multivariate normal linear model Y~N(XB, Σ×V) under the risk of entropy loss function and symmetry loss function criterion, where the design matrix X need not have full rank and the dispersion matrix V can be singular. It is interested to prove that MINQUE is superior to simple estimator under Entropy loss function. Related Articles | Metrics

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The Growth Optimal Portfolio in a General Market Driven by Jump-diffusion Processes XU Zhi-yan 2004, 2004 (2):  37-42.  Abstract ( 6357 )   Save In this paper, We generalize the results of Yan et al［1］ results on the growth optimal portfolio in a market driven by jump-diffusion processes with multi-risky assets. Sufficient conditions for existence of growth optimal portfolio in this case were given. Related Articles | Metrics

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Analysis and Realization of Bluetooth SDP and Its Improvement XIONG Jiang;GU Jun-zhong;XUE Mei 2004, 2004 (2):  43-50.  Abstract ( 3844 )   Save Wireless Network which is based on two protocols: IEEE802.11b and Bluetooth solves the problems of wire communication moving inconvenience, lacking in flexibility and use inconvenience. This paper analyzes and researches system architecture, service search engine and realization of SDP which is working in the embedded mobile environment, and suggests some improvement ideas on its shortage which is concluded from the comparison to IEEE802.11b to enhance its security and transfer speed. Related Articles | Metrics

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Research on Application Model and Key Technology of Pervasive Computing JIANG Guo-hua;GU Jun-zhong 2004, 2004 (2):  51-57.  Abstract ( 2572 )   Save With the development of computer science and communication technologies, Computing patterns are changing. This thesis studies pervasive computing environment and traditional application models. On the research basis, we put forward an appropriate application model according to the characteristics in this new environment. Then we research the key element of the model -service gateway. At last, we adopt this model in the iHome project raised by SVA-IBM joint Lab. It proved its practicability. The proposition of pervasive application model is in the person ’of humanity. It provides a solution to the problems in pervasive computing and is a guide to the continued development of pervasive applications. Related Articles | Metrics

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Bragg Frequency Study of RF Distributed MEMS Phase Shifter QING Jian;SHI Yan-ling;LI Wei;ZHU Zi-qiang;LAI Zong-sheng 2004, 2004 (2):  58-63.  Abstract ( 2820 )   Save The Bragg frequency, which describes the upper limit frequency of distributed phase shifters, is a very important parameter of RF distributed MEMS phase shifters. This paper discusses in detail the underlying cause and analysis method of Bragg frequency. In addition, by using microwave network theory, the Bragg frequencies of MEMS phase shifters with different dimensions have been calculated. The simulated results demonstrate the Bragg frequency is decreased by increase of the dimension and spacing. The studied phase shifters consist of a CPW line (50 Ω) periodically with MEMS bridges at a spacing of 300 μm. When the widths of the center conductor are chosen to be 50 μm and 100μm, the Bragg frequency are 38.1 GHz and 27.6 GHz, respectively. As the width of the center conductor is fixed at 100 μm, the Bragg frequency reduces form 27.6 GHz to 19.6 GHz with the spacing increasing form 300 μm to 567 μm. Researching the Bragg frequency will benefit the design and optimization of the distributed MEMS phase shifters. Related Articles | Metrics

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Magneto-impedance Effect in BeCu/NiFeB Electroless-deposited Wire WANG Xin-zheng;YUAN Wang-zhi;M Oumarou;RUAN Jian-zhong;GONG Feng-fei;ZHAO Zhen-jie;YANG Xie-long 2004, 2004 (2):  64-68.  Abstract ( 2879 )   Save NiFeB films were electroless-deposited on 100 μm BeCu wires and were annealed at different temperatures in N2 atmosphere. The dependence of GMI on the annealing temperature and frequencies of driving current was studied. The maximum GMI ratio of 33% of these sample was observed by annealing at 200 ℃. After adding the insulator layer between BeCu and NiFeB layer the GMI ratio of the sample increases to 83%. Related Articles | Metrics

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Study on the Synthesis of 5-FAsA-DBF and Its Chromogenic Reaction with Thorium XU Feng;HAO Zheng-wen;GAO Mei-rong;WU Bing-cai 2004, 2004 (2):  69-71,8.  Abstract ( 2778 )   Save A new chromogenic reagent 5-FAsA -DBF was synthesized and its colour reaction with thorium was studied， In a perchloric acid medium of 3.84 mol•L-1， 5-FAsA-DBF reacted with thorium to form a stable coordinate-complex， having its absorption maxima at 630 nm.Its molar absorptivity was found to be 1.63×105 L•mol-1•cm-1 .Beer’s law holds in the concentration range of 0～40 μg of Th(Ⅳ) per 25 mL of solution.The method has been apllied to determinate thorium in seafood with satisfactory results. Related Articles | Metrics

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The Basic Character on Process of Runoff and Sediment Discharge at Datong Station of the Changjiang River Ⅰ. Analysis on Runoff Process WANG Pan-cheng;HE Song-lin 2004, 2004 (2):  72-80.  Abstract ( 3362 )   Save The Changjiang estuary is a typical estuary that fluvial factors plays a dominant role in fluvio-marine interaction. The process and its variation of runoff and sediment discharge have situation under control in respect of evolution of the estuarine environment. This paper studies main characters of runoff process at Datong Station with methods of time-series analysis. It is stated that the runoff series at Datong Station has little change trend since 1923, but a jumped decrease near 1955 and a jumped increase near 1988 have emerged. Meanwhile, it has a certain appearance of periodic variation with around 16,7 years. The distribution patterns of monthly flow, the matching state of high or low water between flood and dry season as well as the relevant causes are also discussed in the paper. Related Articles | Metrics

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The Basic Character on Process of Runoff and Sediment Discharge at Datong Station of the Changjiang River Ⅱ. Analysis on sediment transport process HE Song-lin;WANG Pan-cheng 2004, 2004 (2):  81-86,1.  Abstract ( 3188 )   Save The Changjiang river is rich in sediment supply which exerts an important influence on development of the Changjiang delta, evolution of shoals and channels in the estuary, realignment and utilization of the estuary. Trend analysis and period analysis on the sediment transport series at Datong Station state that an obvious decrease trend has emerged in the annual series of sediment transport at Datong Station although the sediment discharge at Yichang Station and the annual runoff series at Datong Station have little change trend. The situation is mainly related to shoaling of Dongting Lake, Poyang Lake and other lakes. The sediment-producing region is mostly located in the upper reach and sediment-producing effect of upper, middle and lower reaches is obviously different, so that sediment transporting situation is responded with runoff discharge only about 30% of years in the series. As for monthly distribution of sediment discharge, some 87.7% of suspension loads are discharged through the Datong section from May to Octorber. In addition, the matching status of sediment discharge between flood and dry seasons is preliminarily analyzed in the paper. Related Articles | Metrics

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Observation and Modeling Analysis of Dynamic Mechanism of the Upwelling at Lusi ZHU Jian-rong;QI Ding-man;WU Hui 2004, 2004 (2):  87-91,1.  Abstract ( 2920 )   Save Based on the analysis of the observation we organized in August of 2000 off the Changjiag mouth,we found for the first time that there exists upwelling phenomenon at Lusi fish ground.The upwelling can bring the colder water and nutrient from the lower layer to the upper layer,and has an important effect on the environment and ecosystem.In order to understand the dynamic mechanism of the upwelling phenomenon,we used a three-dimension high resolution turbulent closure circulation model in spherical coordinates based on the modified ECOM_si model to study this upwelling.The calculated domain includes the East China Sea,Yellow Sea and Bohai Sea,and the real coastline and water depth were considered.In the case of considering all dynamic factors (water volume flux at the open boundaries,density gradient forcing and wind stress),the numerical model reconstructed successfully the upwelling phenomenon which is fairly consistent with the observations.The numerical experiments show that the dynamic mechanism of the upwelling is mainly produced by the baroclinic effect that is induced by the mixing between fresh water from the Changjiang River and the saline water.The wind stress has a little effect on it,and the water volume flux at open boundaries has no effect on it.The combination force of the slop of bottom with the baroclinic effect and wind stress makes the upwelling stronger. Related Articles | Metrics

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Effects of Procyanidins on Preventing Mitochondria Damage in Rat Liver Induced by •OH CHEN Ji-wu;ZHU Zhen-qin;SU Yu;WANG Ni;CAO Jia-qi;LIU Guo-wei;HU Bing;ZHAI Wan-yin 2004, 2004 (2):  92-96.  Abstract ( 3325 )   Save Oxidative damage of the mitochondria plays an important role in generating and developing process of many diseases.Hydroxyl radical (•OH) has been considered an important factor inducing mitochondria damage.Therefore,it has important significance to study and exploit medicines protecting mitochondria damage caused by •OH.We measured effects of procyanidins preventing mitochondria damage induced by•OH using spectrophotometry and fluorescent polarimetry.The results showed that procyanidins increased effectively membrane lipids fluidity of damaged mitochondria,decreased significantly the mitochondria swelling and lipid peroxidation product formation.As a result,procyanidins can maintain the integrity of structure and function of mitochondria.Above results can provide new data for further exploitation of procyanidins. Related Articles | Metrics

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The Definition and Types of Urban Ecological Sensitive Area with the Case Study in Pudong New Area,Shanghai,China DA Liang-jun;LI Li-na;LI Wan-lian;CHEN Ming 2004, 2004 (2):  97-103.  Abstract ( 3547 )   Save This paper discusses different points of view about the concept of ecological sensitive area and proposes that the green field should be included in the conception of urban sensitive areas to prevent the irregular expand of urban.Based on this conception,the ecological sensitive areas are classified into five types namely ①nature-protection type,②environment-improvement type,③field-control type,④pollution-effect type and ⑤resource-reserve type.As a case study,the types of eological sensitive area in Pudong New Area were classified and the suggestions on the consrtuction of ecological sensitive area were put forward. Related Articles | Metrics