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computer SIMULATION OF RAYLEIGH FADING CHANNELS IN MC-CDMA SYSTEMS

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Journal of Electronics(china) 2007年第5期24卷 577-582页

作者： Han Fangming Zhang Xianda National Laboratory of Radar Signal Processing Xidian University Xi＇an 710071 China National Laboratory of tsinghua information science and technology Department of AutomationTsinghua University Beijing 100084 China

For Multi-Carrier-Code Division Multiple Access （MC-CDMA） systems, it is usually assumed that the fading of the subcarriers is frequency non-selective and independent of each other. This paper shows that the two assumptions are incompatible. In fact, the MC-CDMA signals at each subcarrier undergo fading that are highly correlated. Based on this observation, this paper develops a simulation algorithm for Rayleigh fading channels via frequency-domain correlation functionl which incorporates the Doppler effect simultaneously. Numerical examples are presented to demonstrate the effectiveness of the new algorithm, with the conclusion that the independence assumption of subcarrier fading overrates the system performance.

关键词： Multi-Carrier-Code Division Multiple Access (MC-CDMA) Rayleigh fading Channelsimulation Frequency-domain correlation

Mathematical Model for the Drying Process of Granular Materials in a Fluidized Bed

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 296-300页

作者： Xiulan Huai, Li Wang, Zhiyun Qu ( Mechanical Engineering School, university of science and technology beijing, beijing 100083, china Chemical Industry Research Institute of Shanxi, Taiyuan 030031, china) Mechanical Engineering School University of Science and Technology Beijing Beijing 100083 China Chemical Industry Research Institute of Shanxi Taiyuan 030031 China

The experiment of granular materials, barley, drying in a fluidized bed was carried out to investigate the influence of the factors, inlet air temperature, air moisture, bed height and original moisture content of the dried materials on drying process. Based on the experimental data, a corresponding mathematical model is presented. As a conclusion, a higher inlet air temperature and a reasonable bed height should be used so as to increase the dring rate and to improve the product quality.

关键词： fluidization granular materials drying, experimental investigation mathematical model information

Development of Chinese characterization factors for land use in life cycle impact assessment

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science china(Technological sciences) 2010年第6期53卷 1483-1488页

作者： LIU Yu,NIE ZuoRen,SUN BoXue,WANG ZhiHong & GONG XianZheng School of Materials science and Engineering,beijing university of technology,beijing 100124.china 1. School of Materials science and Engineering Beijing University of Technology Beijing 100124 China

A model with Chinese characterization factors for quantifying the damages to environment by land use in terms of the change in net primary productivity (NPP) of ecosystem was developed in the framework of life cycle assessment (LCA).In this method,the forms of land utilization were divided into two aspects involving long-term use of land (e.g.,for arable farming),namely "land occupation",and the change of land properties (e.g.,from agricultural area to urban area),namely "land transformation".Furthermore,the land use elementary flows (occupation and transformation) and parameters were linked to the impact indicators,and the characterization formulas of the two forms of land utilization were derived respectively according to the ecological ***,based on this method,the characterization factors of both land occupation and land transformation were calculated using Chinese empirical information on NPP,which can be incorporated into LCA framework and applied to Chinese LCA case study to fill up the important gap in life cycle impact assessment (LCIA) of land use.

关键词： life cycle assessment land use net primary productivity

Power allocation scheme for selfish cooperative communications based on game theory and particle swarm optimizer

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science china(information sciences) 2010年第9期53卷 1908-1912页

作者： ZHANG GuoPeng1*,YANG Kun2 & DING EnJie3 1School of computer science and technology,china {4. of Mining and technology,Xuzhou 221116,china 2School of computer science and Electronic Engineering,{4. of Essex Wivenhoe Park,Colchester CO_4.3SQ,UK 3School of information and Electrical Engineering,china {4. of Mining and technology,Xuzhou 221116,china 1. School of computer science and technology China University of Mining and Technology Xuzhou 221116 China2. School of Computer Science and Electronic Engineering University of Essex Wivenhoe Park Colchester CO4 3SQ UK3. School of Information and Electrical Engineering China University of Mining and Technology Xuzhou 221116 China

In commercial networks,autonomous user nodes operating on batteries are assumed to be selfish to consume their energy solely to maximize their own benefits,e.g.,data *** this letter a two-user cooperative game is proposed to perform the power allocation for selfish cooperative communication *** the game,one selfish user node could trade its transmission power for the other ones cooperative relaying directly,and both user nodes are willing to achieve an optimal data-rate increase through cooperative *** find the Nash bargaining solution(NBS) of the game,a low-complexity numerical particle swarm optimizer(PSO) algorithm is also *** results indicate that the NBS of the game is efficient,in that both users could experience better performance than they work independently,and fair,in that the degree of cooperation of a user node only depends on how much contribution its partner can make to improve its own performance.

关键词： cooperative communication power allocation game theory Nash bargaining solution particle swarm optimizer

XPS Studies of Magnetic Multilayers

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Journal of university of science and technology beijing 2001年第3期8卷 210-213页

作者： Guanghua Yu, Hongchen Zhao, Jiao Teng, Chunlin Chai, Fengwu Zhu, Yang Xia, Shumin Chai Material science and Engineering School, university of science and technology {4., {4. 100083, china Microelectronics Center, Chinese Academy of science, Beijin Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Chinese Acad Sci Ctr Microelect Beijing 100029 Peoples R China

NiOx/Ni81Fe19 and Co/AlOx/Co magnetic multilayers were fabricated by reactive RF/DC magnetron sputtering on clean glass substrates and oxidized Si (100) substrates, respectively. The exchange biasing field (H-ex) between NiO4.and Ni81Fe19 as a function of NiOx oxidation states was studied by X-ray photoelectron spectroscopy (XPS). The oxidation states and the oxide thickness of Al layers in magnetic multilayer films consisting of Co/AlOx/Co were also analyzed. It is found that the H-sr of NiOx/Ni81Fe19 films only depends on Ni2+ but not on Ni3+ or Ni. The bottom Co can be completely covered by depositing an A I layer thicker than 2.0 nm. The oxide layer was Al2O3, and its thickness was 1.15 mn.

关键词： NiOx exchange biasing field H-ex AlOx X-ray photoelectron spectroscopy (XPS)

The geometrical structure, electronic structure and magnetism of bimetallic Au_nM_2 (n=1, 2; M=Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd) clusters

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science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 1011-1020页

作者： GU Juan1,2, WANG ShanYing2 & GOU BingCong1 1 Department of Physics, beijing Institute of technology, beijing 100081, china 2 Department of Physics, {4., beijing 100084, china Department of Physics Beijing Institute of Technology Beijing 100081 China Department of Physics Tsinghua University Beijing 100084 China

The geometrical structure, stability, magnetism, and electronic structure of bimetallic clusters AuM2 and Au2M2, where M are 4. transition metal elements, are investigated systematically by using the first-principles method based on density functional theory. The calculation results show that there is a large amount of low-energy isomers with the very similar structure. AuM2 and Au2M2 clusters display dramatic magnetism. The magnetic moment of the 4. element is either enhanced or weakened with respect to the bulk value, which is largely dependent on the orbital exchange-splitting.

关键词： density functional theory first-principles cluster electronic structure magnetism

Perfect reconstruction image modulation based on BEMD and quaternionic analytic signals

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science china(information sciences) 2011年第12期54卷 2622-2634页

作者： QIAO LiHong 1 , NIU KaiFu 2 , WANG Ning 2 & PENG LiZhong 2 1 college of information science and Engineering, Henan university of {4., Zhengzhou 4.0001, china 2 School of Mathematical sciences, Peking university, beijing 100871, china 1. college of information science and Engineering Henan University of Technology Zhengzhou 450001 China2. School of Mathematical Sciences Peking University Beijing 100871 China

Image modulation represents image by meaningful characters such as image instantaneous amplitude and instantaneous frequency. A perfect reconstruction image modulation method is proposed. In detail, the bidimensional empirical mode decomposition (BEMD) is first improved to adaptively decompose image into monocomponents. Then by the quaternionic analytic method, suitable analytic signals is acquired. A new polar form is further proposed to modulate images, then seven characters are derived including instantaneous amplitude and instantaneous frequencies. We demonstrate the techniques on both synthetic and natural images, depict the needle program of the estimated frequencies and obtain the reconstructions that are the same with the original images. The applications in image segmentation and separation establish the validity of characterizing images of this type as sums of locally narrow band modulated components.

关键词： perfect reconstruction image modulation AM-FM representation BEMD quaternionic analytic signals

High Quality SiGe Layer Deposited by a New Ultrahigh Vacuum Chemical Vapor Deposition System

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Journal of Materials science & technology 2000年第1期16卷 94-96页

作者： Guangli LUO, Xiaofeng LIN, Peiyi CHEN and Peixin TSIAN (Institute of Microelectronics, tsinghua university, beijing 100084, china Institute of Microelectronics Tsinghua University Beijing 100084 China

An ultrahigh vacuum chemical vapor deposition (UHV/CVD) system is developed and the details of its construction and operation are reported. Using high purity SiH4.and GeH4.reactant gases, the Si0.82Ge0.18 layer is deposited at 550℃. With the measurements by double crystal X-ray diffraction (DCXRD), transmission electron microscopy (TEM) and Rutherford backscattering spectroscppy (RBS) techniques, it is shown that the crystalline quality of the SiGe layer is good, and the underlying SiGe/Si heterointerface is sharply defined.

关键词： SiGe high High Quality SiGe Layer Deposited by a New Ultrahigh Vacuum Chemical Vapor Deposition System

Construction of AFLP-based genetic linkage maps for the Chinese shrimp Fenneropaeneus chinensis

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Chinese science Bulletin 2008年第8期53卷 1205-1216页

作者： TIAN Yi1,2,3,4. KONG Jie1↑ & WANG WeiJi1 1 Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery science, Qingdao 266071, china 2 college of Life science and {4., Dalian Fisheries university, Dalian 116023, china 3 Institute of Oceanology, Chinese Academy of sciences, Qingdao 266071, china 4.Graduate university of Chinese Academy of sciences, beijing 10004., china Chinese Acad Fisheries Sci Yellow Sea Fisheries Res Inst Qingdao 266071 Peoples R China.

Fenneropaeneus chinensis is an important species in marine fishery resources and aquaculture in china. A genetic linkage map is essential for improving the efficiency of its breeding by marker-as- sisted selection and identifying commercially important genes. Linkage maps of F. chinensis were constructed with an F2 mapping population (110 progenies) using amplified fragment length polymor- phic (AFLP) marker in this study. Fifty-five AFLP primer combinations produced 532 AFLP markers fitting for map strategy in mapping family. The markers with 3:1 segregating ratios were analyzed using F2 intercross model for the common linkage map, while the markers with 1:1 ratio were analyzed using the pseudo-testcross strategy. The maps of male, female and common were constructed. The female map included 103 markers that formed 28 linkage groups, covering a total length of 1090 cM. All mark- ers were linked with the linkage groups. Segregation distortion was observed for 6 of 103 markers in the female map. The average distance between markers was 14.53 cM and ranged from 4.4.to 24.8 cM. The male map included 14. markers that formed 35 linkage groups. Ten markers remained unlinked in male map. Segregation distortion was observed for 7 of 14. markers in the male map. The total dis- tance of male map covered 1617 cM. The average distance between markers was 16.36 cM. The male map was 32.6% longer than the female map, which may reflect sex-specific recombination rates in Chinese shrimp. The common map was composed of 216 markers, including in 4. linkage groups covering a total distance of 1772.1 cM. Two markers remained unlinked. No distorted markers of 216 markers were shown in the common map. The distance between markers was 10.4. cM. An average estimated genome size for the Chinese shrimp was 24.0 cM, which was consistent with the relative size of the Penaeid genome. The distribution of AFLP markers was relatively even in chromosomes of Chi- nese shrimp maps. The linkage analysis

关键词： AFLP 海洋渔业虾中国