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Influence of TiO_2 Mineralizer on the Crystalline Structure of Cordierite Synthesized from Aluminum Slag

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Chinese Journal of Structural Chemistry 2005年第5期24卷 596-600,493页

作者：阮玉忠吴任平于岩 College of Materials Science and Engineering Fuzhou University Fuzhou 350002 China

By adding small amount of TiO2, aluminum slag could be used to synthesize cor- dierite. α-Al2O3, TiO2 and dehydrated talc could generate solid solution to accelerate the solid-state reaction to form cordierite. The experimental results show that the content of cordierite increases with the increase of TiO2 added. 3.0% of TiO2 is determined to be the best amount, because all crystalline substances are converted into cordierite at this content. Philips X’pert plus software analysis shows that when the content of TiO2 is from 0 to 1.0%, cordierite has the same hexagonal structure as the single crystal and the lattice parameters change slightly; when the content of TiO2 is from 1.0 to 2.0%, the cordierite still keeps hexagonal structure but the lattice parameters change greatly; when the content of TiO2 is from 2.0 to 3.5%, the cordierite is converted from hexagonal into rhombic and the lattice parameters change accordingly.

关键词： aluminum slag TiO2 mineralizer cordierite crystalline structure

Cross-Band Spectrum Prediction Algorithm Based on Data Conversion Using Generative Adversarial Networks

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中国通信:英文版 2023年第10期20卷 136-152页

作者： Chuang Peng Rangang Zhu Mengbo Zhang Lunwen Wang College of Electronic Engineering National University of Defense TechnologyHefei 230037China

Spectrum prediction is one of the new techniques in cognitive radio that predicts changes in the spectrum state and plays a crucial role in improving spectrum sensing *** models previously trained in the source band tend to perform poorly in the new target band because of changes in the *** addition,cognitive radio devices require dynamic spectrum access,which means that the time to retrain the model in the new band is *** increase the amount of data in the target band,we use the GAN to convert the data of source band into target ***,we analyze the data differences between bands and calculate FID scores to identify the available bands with the slightest difference from the target predicted *** original GAN structure is unsuitable for converting spectrum data,and we propose the spectrum data conversion GAN(SDC-GAN).The generator module consists of a convolutional network and an LSTM module that can integrate multiple features of the data and can convert data from the source band to the target ***,we use the generated target band data to train the prediction *** experimental results validate the effectiveness of the proposed algorithm.

关键词： cognitive radio cross-band spectrum prediction deep learning generative adversarial network

Studies on the Structure and Properties of Multiphase Al_2O_3 Abrasion-resistant Ceramics

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Chinese Journal of Structural Chemistry 2006年第7期25卷 805-810页

作者： WU Ren-Ping YU Yan RUAN Yu-Zhong College of Materials Science and Engineering Fuzhou University Fuzhou 350002 China

The Al2O3 abrasion-resistant ceramics is successfully prepared by using waste aluminum sludge as the main raw material with the addition of a little clay, talc and barium carbonate. The crystal structure and microstructure of ceramic are characterized by means of XRD, SEM, etc., and the physical and mechanical properties are also tested. The results show that besides the phase of corundum, a little mullite, Mg-Al spinel and hyalophane phases also exist in the product. These phases are produced via reaction in-situ, which can inhibit the overgrowth of Al2O3 grain in grain boundary, and improve the integral property of the material.

关键词： Al2O3 ceramic crystal structure property in-situ synthesis

Effect of Cerium on Microstructures and High Temperature Oxidation Resistance of An Nb-Si System In-Situ Composite

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Journal of Rare Earths 2007年第4期25卷 474-479页

作者：刘爱勤孙璐李树索韩雅芳 School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics

Nb-16Si-24Ti-6Cr-6A1-2Hf-xCe （x =0, 0.05, 0.1,02.5, 0.5, 1 （%, atom fraction）） in situ composites were prepared by arc melting The microstmcture and the effect of rare earth element cerium on 1250℃ oxidation resistance of the composites were investigated with scanning electron microscopy （SEM） and X-ray energy disperse spectrum （EDS）, as well as X-ray diffraction （XRD）. The experimental results showed that the high temperature oxidation resistance of the alloy was improved by adding a proper amount of cerium （Ce）. The effect of Ce was considered as the concurrent of the following three factors： first, the oxide of Ce formed in the interface reduced the internal oxidation rate; second, the lath shaped oxide containing Ce increased the cracking resistance and reduced the expansion of the oxide scale; and third, the decrease of the sificide volume fraction on account of Ce addition reduces the power of the sample resisting oxygen penetration.

关键词： oxidation resistance in-situ composite Nb-Si alloy rare earths

A Four-Wavelength All-Fiber Laser for Wavelength Division Multiplexing System

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Chinese Physics Letters 2001年第3期18卷 376-378页

作者：丁镭开桂云徐雁军关柏鸥袁树忠董孝义葛春风 Institute of Modern Optics Nankai UniversityTianjin 300071 College of Precision Instrument&Optoelectronics Tianjin UniversityTianjin 300072

A novel four-wavelength all-fiber laser based on fiber Bragg gratings is *** four wavelengths are 1555.8,1556.6,1557.4 and 1558.2 nm,*** output laser is1 mW in *** suppression ratio between adjacent wavelengths is>30 *** laser was applied in a wavelength division multiplexing(WDM)system and the 100 km transmission of 1.2 Gb/s nonreturn-to-zero code,1.2 Gb/s return-to-zero code,2.5 GHz analogue signal and 5 GHz analogue signal was realized with it.

关键词： Gb/s fiber laser

Initial pre-stress finding procedure and structural performance research for Levy cable dome based on linear adjustment theory

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第9期8卷 1366-1372页

作者： ZHANG Li-mei CHEN Wu-jun DONG Shi-lin Space Structures Research Center Shanghai Jiao Tong University Shanghai 200030 China

The cable-strut structural system is statically and kinematically indeterminate. The initial pre-stress is a key factor for determining the shape and load carrying capacity. A new numerical algorithm is presented herein for the initial pre-stress finding procedure of complete cable-strut assembly. This method is based on the linear adjustment theory and does not take into account the material behavior. By using this method,the initial pre-stress of the multi self-stress modes can be found easily and the cal-culation process is simplified and efficient also. Finally,the initial pre-stress and structural performances of a particular Levy cable dome are analyzed comprehensively. The algorithm has proven to be efficient and correct,and the numerical results are valuable for practical design of Levy cable dome.

关键词：线型调节理论缆索支撑结构初始前压力建筑结构结构性能分析

Distribution and resource evaluation of natural gas hydrate in South China sea by combing phase equilibrium mechanism and volumetric method

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Petroleum Science 2022年第1期19卷 26-36页

作者： Tong Wang Tao Hu Xiong-Qi Pang Xing-Wen Zhang Xiao-Han Liu Zhi Xu En-Ze Wang Zhuo-Ya Wu State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China College of Geosciences China University of Petroleum(Beijing)Beijing102249China School of Earth&Space Sciences Peking UniversityBeijing100871China Research Institute of Petroleum Exploration and Development PetroChina Company LimitedBeijing100083China

China Geological Survey conducted the second trial production of natural gas hydrate(NGH)in the Shenhu Area in South China Sea(SCS)from 2019 to *** with the first trial production in 2017,the second trial showed significantly increased daily gas production and total gas production,and removed some technical obstacles for large-scale NGH resource developments in the ***,current NGH resource evaluation in the SCS is still at the stage of prospective gas content assessment,which is unable to guide further NGH exploration and *** study utilized the hydrate phase balance to delineate the NGH distribution range and effective thickness and volumetric method to evaluate NGH *** on the latest exploration and production data from the Shenhu Area,Monte Carlo simulation was performed to calculate the NGH resource amount with different *** assuming a 50%cumulative probability,the in-situ NGH resources in the SCS was estimated to be11.7×10^(12)m^(3) and the recoverable NGH resources was 2.8×10^(12)m^(3).These results will provide a more reliable resource basis for China to formulate comprehensive development strategies for oil and gas exploration in the SCS.

关键词： South China Sea Oil and gas resource Natural gas hydrate In-situ resource Recoverable resources

Analysis and Simulation for Capacity of Time Division-Synchronous Code Division Multiple Access System

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Journal of Systems Engineering and Electronics 2002年第4期13卷 91-97页

作者： Sun Chengjun, Zhang Zhongzhao, Ba Yong2 & Cao Pengzhi (Communication Research ("enter, Harbin Institute of Technology, Harbin 150001, P. R. China Department of Electronic Engineering, Tsinghua University, Beijing 100084, P. R. China Research and Development Division, Shanghai Bell Company Limited, Shanghai 200092, P. R. China) Communication Research Center Harbin Institute of Technology Harbin 150001 P. R. China Department ot Electronic Engineering Isinghua University Beijing 100084 P. R. China Research and Development Division Shanghai Bell Company Lirmted Shanghai 200092 P. R. China

Capcity both in uplink and downlink of TD-SCDMA (time division-synchronous code division multiple access) system is studied in a multi-cell environment. The theoretical expressions of the mean of intercell interference in uplink and the mean of sum of power allocation in downlink are given, by which uplink and downlink capacity is analyzed. Furthermore, we give the simulation models for both uplink and downlink capacity. The results from theoretical analysis and simulation fit very well. In the end, the maximum number of users that TD-SCDMA system can serve for 12.2 k speech service is given.

关键词： Code division multiple access Probability Resource allocation Simulation Time division multiple access

Design and performance simulation of a molecular Doppler wind lidar

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Chinese Optics Letters 2009年第7期7卷 593-597页

作者：沈法华 Hyunki Cha 董吉辉 Dukhyeon Kim 孙东松 Sung Ok Kwon Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Korea Atomic Energy Research Institute Hanbat National University

A mobile molecular Doppler wind lidar at an eye-safe wavelength of 355 nm based on double-edge technique is being built in Hefei （China） for wind measurement from 10-to 40-km altitude. The structure of this lidar system is described. A triple Fabry-Perot etalon is employed as a frequency discriminator whose parameters are optimized. The receiver system is designed to achieve compactness and stability by putting in a standard 19-inch socket bench. Simulation results show that within the wind speed dynamic range of ±100 m/s, the horizontal wind errors due to noise are less than 1 m/s bdow 20-km altitude for 100-m vertical resolution, and less than 5.5 m/s from 20 km up to 40 km for 500-m vertical resolution with 400-mJ laser energy, 30-min temporal resolution, and a 45-cm aperture telescooe.

关键词： Optical radar