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Synchronization of MIMO OFDM systems by perfect complete generalized complementary orthogonal loosely synchronous code groups

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The Journal of china.Universities of Posts and telecommunications 2009年第2期16卷 1-7页

作者： wang Jian YANG Xun LI Dao-ben school of Information Engineering,beijing university of Posts and {4.,beijing 100876,china [a]school of Information Engineering beijing university of Posts and telecommunications beijing 100876 china

This article proposes a time/frequency synchronization algorithm in the multiple input multiple output （MIMO） systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence. The synchronization algorithm is divided into four stages： 1） synchronization in time domain by signal autocorrelation; 2） synchronization in frequency domain by fast Fourier transform （FFT）; 3） multipath dissociation using coherent detection and fine time synchronization; 4. fine frequency offset estimation by phase rotation. As per the perfect complete generalized complementary orthogonal loosely synchronous code groups, the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The simulation results show that even in the multipath fast fading channel with low signal noise ratio （SNR）, the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.

关键词： MIMO OFDM synchronization complementary orthogonal code loosely synchronous (LS) code

Sol-gel Preparation and Infrared Radiation Property of Boron-substituted Cordierite Glass-ceramics

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Journal of Materials science & Technology 2010年第5期26卷 445-448页

作者： Shuming wang and Fenghua Kuang school of Materials science and Engineering,university of science & Technology beijing,beijing 100083,china [a] school of Materials science and Engineering university of science & Technology beijing beijing 100083 china

Boron for aluminum substitution in the cordierite structure has been examined by sol-gel preparation of different samples along the compositional junction Mg2Al4.xBxSi5O18 with x=0,0.5,1,*** increasing the x value from 0 to 1.5 the crystallization behavior changed *** amount B2O3 doping can promote the sintering of amorphous cordierite gel,effectively restrain the precipitation of μ-cordierite and enhance the crystallization of α-*** substitution of B3＋ for Al3＋ in cordierite crystal structure can effectively improve the near-infrared spectral emissivity of this cordierite based glass-ceramics.

关键词： Sol-gel Glass-ceramics Infrared radiation B3+ substitution Solid solution

Development and application of ergodicity model with FRCM and FLAR for hydrological process

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science china.Technological sciences) 2009年第2期52卷 379-386页

作者： wang HongRui1, FENG QiLei2, LIN Xin3 & ZENG WenYi4.1 College of Water science, Key Laboratory for Water and Sediment sciences of the Ministry of Education, beijing Normal {4., beijing 100875, china.2 school of science, beijing Institute of Education, beijing 100011, china.3 school of Mathematical sciences, beijing Normal {4., beijing 100875, china.4.College of Information science and Technology, beijing Normal {4., beijing 100875, china 1. College of Water science Key Laboratory for Water and Sediment Sciences of the Ministry of Education Beijing Normal University Beijing 100875 China 2. school of science Beijing Institute of Education Beijing 100011 China 3. school of Mathematical sciences Beijing Normal University Beijing 100875 China 4. College of Information science and Technology Beijing Normal University Beijing 100875 China

In this paper, a new ergodic property analysis model of hydrological process is proposed based on fuzzy-rough c-means clustering (FRCM), autocorrelogram, and fuzzy least absolute regression (FLAR). A precipitation time series (1951―2004. from Shanghai Hydrology Station is then analyzed with the model. The results show that the precipitation time series of April, May, June, and September has er-godic property. We conclude that in the long run, the precipitation of April, May, June, and September will not keep decreasing; it will converge to its mean value in some period.

关键词： hydrological process ergodic autocorrelogram fuzzy-rough c-means clustering fuzzy least absolute regression

RECOGNITION AND CLASSIFICATION FOR O(n)-EQUIVARIANT BIFURCATIONS WITH O(n)-CODIMENSION LESS THAN 5

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Chinese Annals of Mathematics,Series B 1998年第4期19卷 391-400页

作者： wang XIAOFENG (Department of Applied Mathematics, Tsinghua university, beijing 100084. china.)TANG YUN (Department of Applied Mathematics, Tsinghua university, beijing 100084. china.)wang DUO (school of Mathematical science, Peking universityl Beliing 10 Tsing Hua Univ Dept Appl Math Beijing 100084 Peoples R China Peking Univ Sch Math Sci Beijing 100080 Peoples R China

Bifurcation problems equivariant under the standard action of the orthogonal group O(n) up to O(n)-codimension 4.are classified into 19 classes. For each class the normal form and one universal unfolding are calculate... 详细信息

关键词： O(n)-equivariant bifurcation Normal form Universal unfolding Recognition problem

Mechanism of Cathode Process of B(Ⅲ) in LiF-NaF-KBF_4.Meltby Electrochemical Titration Technique

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International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 203-207页

作者： Qingrong Shi Xindong wang Lianyu Yuan Shuzhen Duan(Applied science school, university of science and Technology beijing, beijing 100083, china. Applied science school University of Science and Technology Beijing Beijing 100083 China

The mechanism of cathode process of B(Ⅲ) at molybdenum and platinum electrodes in LiF-NaF-KBF4.elt was studied and the transferred electron number of the reaction was calculated by means of cyclic *** effect of adsorption of electroactive component on the electrochemical response (e. g., the voltammetric i─Ecurves) was analyzed and discussed. The 'electrochemical spectra' for linear sweep voltammetry was used to elucidate the electrode reaction accompanied by a following transform process. The results show that the reduction ofB(Ⅲ) to B(0) proceeds in reversible one step three-electron reaction and the cathode process of B(Ⅲ) is affected byproduct adsorbed strongly at the electrode surface. It is assumed that the reduction and deposition of B(Ⅲ) at molybdenum and platinum electrodes proceed in two kinds of mechanism： (1) B(Ⅲ)＋ 3e = Bads→ B (surface diffusiondeposition mechanism) and (2) B(Ⅲ) ＋ 3e = B (direct deposition mechanism).

关键词： boron ions cathode process cyclic voltammetry fluoride melt

Nonequilibrium Thermodynamic and Dissipative Structure Mechanism of Fluidized Beds

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 90-93页

作者： Maozhan Qi Li wang Xuezi Ni (Mechanical Engineering school, university of science and Technology {4., {4. 100083, china. Mechanical Engineering school University of Science and Technology Beijing Beijing 100083 China

Fluidized beds are nonlinear dynamic systems that exchange mass and energy with outside. They are governed not only byfluid dynamics, but by thermodynamics, especially the second law of thermodynamics as well. According to Prigogine's dissipative structure theory, the following have been concluded: (l) a fixed bed is on thermodynamic blanch, and bubbling, turbulent and fast beds areon the dissipatve structure branches. (2) Entropy in fluidized beds is divided into tWo parts: entropy production and entropy flux. The latter increases with gas velocity and decreases with pressure of the systems. That means the entropy of a system may reduce and the systemwith higher gas velocity behaves as dissipative structure characteristics. (3) For a giVen velocity, a fluidized bed operates stably on thewhole, but it is unstable to local gas-solid phases. The unstable phases are described by fluid dynamic equations, While the minimum ofsystem energy function assures whole stability of the system. (4. A transition criterion of a bubbling bed is derived from Prigogine's stability theory.

关键词： fluidized bed nonequilibrium thermodynamics dissipative structure energy extremum

Refinement of packet size in low carbon bainitic steel by special thermo-mechanical control process

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Journal of university of science and Technology beijing 2004年第3期11卷 221-224页

作者： Chengjia Shang Xuemin wang Shanwu Yang Xinlai He Materials science and Engineering school, university of science and Technology beijing, beijing 100083, china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The packet size of bainitic steel can be refined by a specialrelaxation-precipitation-control phase transformation (RFC) technology. When processed by RPCprocess, the low carbon bainitic steel composes of two kinds of main intermediate transformationphases. One is ultra-fine lath-like bainitic ferrite and the lath is less than 1μm in width andabout 6 μm in length; the alignment of laths forms a refined packet, and the size of packets isabout 5-7 μm in length and about 3-4.m in width. The other is acicular structure. The morphologyand distribution of these acicular structures are influenced by relaxation process, the thin andshort acicular structures cut the prior austenite grain and refine the bainitic packet size. For theoptimum relaxation time, the packet size can be refined to the finest. The mechanical propertiesare influenced by relaxation time and the 800 MPa grade low carbon bainitic steel with excellenttoughness can be obtained by RPC process.

关键词： packet size refinement bainitic steel RPC process

Cancer cell membrane-coated bacterial ghosts for highly efficient paclitaxel delivery against metastatic lung cancer

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Acta Pharmaceutica Sinica B 2024年第1期14卷 365-377页

作者： Dandan Ling xueli Jia Ke wang Qiucheng Yan Bochuan Yuan Lina Du Miao Li Yiguang Jin Anhui Medical university Hefei 230032China Department of Pharmaceutical sciences Beijing Institute of Radiation MedicineBeijing 100850China

Chemotherapy is one of the major approaches for the treatment of metastatic lung cancer,although it is limited by the low tumor delivery efficacy of anticancer *** therapy is emerging for cancer treatment due to its high immune stimulation effect;however,excessively generated immunogenicity will cause serious inflammatory response ***,we prepared cancer cell membrane-coated liposomal paclitaxel-loaded bacterial ghosts(LP@BG@CCM)by layer-by-layer encapsulation for the treatment of metastatic lung *** preparation processes were simple,only involving film formation,electroporation,and pore ***@BG@CCM owned much higher 4.1 cancer cell toxicity than LP@BG due to its faster fusion with cancer *** the 4.1 breast cancer metastatic lung cancer mouse models,the remarkably higher lung targeting of intravenously injected LP@BG@CCM was observed with the almost normalized lung appearance,the reduced lung weight,the clear lung tissue structure,and the enhanced cancer cell apoptosis compared to its ***,several major immune factors were improved after administration of LP@BG@CCM,including the CD4.(+)/CD8a^(+)T cells in the spleen and the TNF-α,IFN-γ,and IL-4.in the ***@BG@CCM exhibits the optimal synergistic chemo-immunotherapy,which is a promising medication for the treatment of metastatic lung cancer.

关键词： Apoptosis Bacterial ghost Cancer cell membrane Immune stimulation Liposome Lung targeting Metastatic lung cancer Paclitaxel

Microstructure and Hot Tearing Sensitivity Simulation and Parameters Optimization for the Centrifugal Casting of Al-Cu Alloy

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Computers, Materials & Continua 2024年第8期80卷 2873-2895页

作者： xueli He Shengkun Lv Ruifeng Dou Yanying Zhang Junsheng wang Xunliang Liu Zhi Wen school of Energy and Environmental Engineering(SEEE) University of Science and Technology Beijing(USTB)Beijing100083China Advanced Research Institute of Multidisciplinary science(ARIM) Beijing Institute of Technology(BIT)Beijing100081China

Four typical theories on the formation of thermal tears:strength,liquid film,intergranular bridging,and solidifica-tion shrinkage compensation *** these theories,a number of criteria have been derived for predicting the formation of thermal cracks,such as the stress-based Niyama,Clyne,and RDG(Rapaz-Dreiser-Grimaud)*** this paper,a mathematical model of horizontal centrifugal casting was established,and numerical simulation analysis was conducted for the centrifugal casting process of cylindrical Al-Cu alloy castings to investigate the effect of the centrifugal casting process conditions on the microstructure and hot tearing sensitivity of alloy castings by using the modified RDG hot tearing *** show that increasing the centrifugal rotation and pouring speeds can refine the microstructure of the alloy but increasing the pouring and mold preheating temperatures can lead to an increase in grain *** grain size gradually transitions from fine grain on the outer layer to coarse grain on the inner ***,combined with the modified RDG hot tearing criterion,the overall distribution of the castings’hot tearing sensitivity was *** analysis results indicate that the porosity in the middle region of the casting was large,and hot tearing defects were prone to *** hot tearing tendency on the inner side of the casting was greater than that on the outer *** effects of centrifugal rotation speed,pouring temperature,and preheating temperature on the thermal sensitivity of Al-Cu alloy castings are summarized in this *** study revealed that the tendency of alloy hot cracking decreases with the increase of the centrifugal speed,and the maximum porosity of castings decreases first and then increases with the pouring *** the preheating temperature increases,the overall maximum porosity of castings shows a decreasing trend.

关键词： Centrifugal casting Al-Cu alloy microstructure hot tearing simulation