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Remote sensing and its applications using GNSS reflected signals:advances and prospects

Satellite Navigation 2024年第1期5卷 10-51页

作者： Shuanggen Jin Adriano Camps Yan Jia Feng Wang Manuel Martin-Neira Feixiong Huang Qingyun Yan Shuangcheng Zhang Zhongyu Li Komi Edokossi Dongkai Yang zhiyu xiao Zhongmin Ma Weihua Bai Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai200030China School of Surveying and Land Information Engineering Henan Polytechnic UniversityJiaozuo454003China Department of Signal Theory and Communications Technical University of CataloniaBarcelona08034Spain Department of Surveying and Geoinformatics Nanjing University of Posts and TelecommunicationsNanjing210023China School of Electronics and Information Engineering Beihang UniversityBeijing100191China European Space Research and Technology Centre(ESTEC) European Space Agency2200-AGNoordwijkThe Netherlands National Space Science Center Chinese Academy of SciencesBeijing100190China School of Remote Sensing and Geomatics Engineering Nanjing University of Information Science and TechnologyNanjing210044China College of Geological Engineering and Geomatics Chang’an UniversityXi’an710054China University of Electronic Science and Technology of China Chengdu611731China

The Global Navigation Satellite Systems(GNSS),including the US’s GPS,China’s BDS,the European Union’s Galileo,and Russia’s GLONASS,offer real-time,all-weather,any-time,anywhere and high precision observations by transmitting L band signals continuously,which have been widely used for positioning,navigation and *** the development of GNSS technology,it has been found that GNSS-reflected signals can be used to detect Earth’s surface characteristics together with other signals of *** this paper,the current status and latest advances are presented on Global Navigation Satellite System-Reflectometry(GNSS-R)in theory,methods,techniques and *** developments and progresses in GNSS-R instruments,theoretical modeling,and signal processing,ground and space-/air-borne experiments,parameters retrieval(*** speed,sea surface height,soil moisture,ice thickness),sea surface altimetry and applications in the atmosphere,oceans,land,vegetation,and cryosphere are given and reviewed in ***,the challenges in the GNSS-R development of each field are also ***,the future applications and prospects of GNSS-R are discussed,including multi-GNSS reflectometry,new GNSS-R receivers,GNSS-R missions,and emerging applications,such as mesoscale ocean eddies,ocean phytoplankton blooms,microplastics detection,target recognition,river flow,desert studies,natural hazards and landslides monitoring.

关键词： GNSS Reflectometry Remote sensing Environmental change

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电气自动化控制设备的可靠性与稳定性分析

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时代汽车 2024年第9期 41-43页

作者：肖志余武汉软件工程职业学院(武汉开放大学) 湖北武汉430205

随着我国信息技术的不断发展,当前电气系统已经成为社会发展过程中的重要基础设施,凭借其自身运行的安全性以及稳定性能够满足各种生产工作的实际需求。同时,随着电气自动化技术的研发发展,电气自动化控制设备越发普及,为确保设备的正... 详细信息

随着我国信息技术的不断发展,当前电气系统已经成为社会发展过程中的重要基础设施,凭借其自身运行的安全性以及稳定性能够满足各种生产工作的实际需求。同时,随着电气自动化技术的研发发展,电气自动化控制设备越发普及,为确保设备的正常运行,需要对电气自动化控制设备的可靠性与稳定性进行分析,并综合电气自动化控制设备运行过程中存在的问题进行探讨,以提出针对性的改进措施,促进我国电气自动化控制设备的正常使用。基于此,本文将从电气自动化控制设备的可靠性与稳定性为出发点,探讨电气自动化控制设备可靠性与稳定性的有效措施,帮助促进我国电气行业健康稳定的发展提供一定意见。

关键词：电气自动化控制设备可靠性稳定性

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Optimized LDPC differential-encoded 16QAM scheme for high-speed transmission systems

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Journal of Systems Engineering and Electronics 2014年第5期25卷 728-734页

作者： Zhanji Wu Xiang Gao zhiyu xiao School of Information and Communication Engineering Beijing University of Posts and Telecommunications Huawei Technology Limited Corporation

The 16-ary quadrature amplitude modulation （16QAM） is a high spectral efficient scheme for high-speed transmission systems. To remove the phase ambiguity in the coherent detection system, differential-encoded 16QAM （DE-16QAM） is usually used, however, it will cause performance degradation about 3 dB as compared to the conventional 16QAM. To overcome the performance loss, a serial concatenated system with outer low density parity check （LDPC） codes and inner DE-16QAM is proposed. At the receiver, joint iterative differential demodulation and decoding （ID） is carried out to approach the maximum likelihood performance. Moreover, a genetic evolution algorithm based on the extrinsic information transfer chart is proposed to optimize the degree distribution of the outer LDPC codes. Both theoretical analyses and simulation results indicate that this algorithm not only compensates the performance loss, but also obtains a significant performance gain, which is up to 1 dB as compared to the conventional non-DE-16QAM.

关键词： quadrature amplitude modulation (QAM) low density parity check (LDPC) code genetic evolution (GE) algorithm iterative demodulation and decoding (ID) extrinsic information transfer (EXIT) chart.

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低成本TiH_(2)粉末制备Ti/(TiB+TiC)复合材料的组织与性能

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粉末冶金技术 2024年第2期42卷 135-143页

作者：林东键柳中强唐浩张建涛肖志瑜华南理工大学国家金属近净成形工程技术研究中心广州510640

使用低成本的TiH_(2)粉末代替纯钛粉,通过添加B4C原位生成TiB和TiC两种增强相,经过真空无压烧结及热挤压工艺制备出具有优异力学性能的Ti/(TiB+TiC)钛基复合材料,分析了制备工艺和增强相对复合材料组织与性能的影响。结果表明,TiH_(2)... 详细信息

使用低成本的TiH_(2)粉末代替纯钛粉,通过添加B4C原位生成TiB和TiC两种增强相,经过真空无压烧结及热挤压工艺制备出具有优异力学性能的Ti/(TiB+TiC)钛基复合材料,分析了制备工艺和增强相对复合材料组织与性能的影响。结果表明,TiH_(2)粉末具有较好的烧结活性,脱氢烧结样品的相对密度可达97.7%;经热挤压工艺,相对密度进一步提升到99.9%,接近于全致密。增强相TiB为短纤维状,TiC为颗粒状,均匀分布在等轴α-Ti基体中,能抑制等轴晶的长大,细化晶粒。热挤压工艺能进一步细化晶粒,使组织更加均匀致密,挤压态钛基复合材料具有高硬度和良好的强塑性匹配。TiH_(2)+4%B4C(体积分数)挤压态复合材料维氏硬度Hv0.3310,屈服强度683 MPa,抗拉强度851 MPa,断后伸长率15.1%。

关键词： TiH2粉末钛基复合材料热挤压显微组织力学性能

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Effect of Free-fall Nozzle Channel Dispersion Angle on TC4 Discontinuous Droplets Pre-breakup in EIGA

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Journal of Wuhan University of Technology(Materials Science) 2023年第1期38卷 171-183页

作者：邹海平 LI Fenglei NGAI Tungwai xiao zhiyu National Engineering Research Centre of Near-Net Shape Forming for Metallic Material South China University of TechnologyGuangzhou 510640China Jiangxi Qianyue New Materials Co. Ltd.Ganzhou 341003China Hejun College Ganzhou 342600China

The effect of the inlet gas pressure,supplementary gas pressure and nozzle channel dispersion angle on the pre-breakup behavior of Ti-6Al-4V(TC4)discontinuous droplets during EIGA was investigated by combining numerical simulation with *** results show that the axial velocity at the recirculation zone before the stagnation location was first increased and decreased then increased significantly after the peak value,while the pressure of the recirculation zone increased with the increase in inlet *** the supplementary pressure increasing,the velocity magnitude and range of the recirculation zone gradually *** the dispersion angle of the nozzle channel increased,the pre-breakup efficiency of droplets gradually decreased,but the adhesion phenomenon of droplets on the inner wall surface of the nozzle channel(IWSNC)gradually *** the inlet pressure of 4 MPa,a supplementary pressure of 0.05 MPa,and the dispersion angle of 15°,the uniform and spherical TC4 powders with diameter of 70μm were prepared,which was consistent with the simulation *** optimized process parameters is a balance between the size of the pre-atomized particles and the back-spraying and bonding phenomenons of droplets.

关键词： discontinuous droplets dispersion angle numerical simulation pre-breakup EIGA

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Structural characteristics and magnetic properties of bulk nanocrystalline Fe_(84)Zr_2Nb_4B_(10) alloy prepared by mechanical alloying and spark plasma sintering consolidation

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Rare Metals 2012年第3期31卷 255-259页

作者： Tang, Cuiyong xiao, zhiyu Luo, Fei Wang, Jun Ma, Chunyu Zhang, Wen National Engineering Research Center South China University of Technology Guangzhou 510640 China

Magnetic properties of Fe84Zr2Nb4B10 sample were investigated. The sample was produced from nanocrystalline powders made by the mechanical alloying (MA) and consolidation using the spark plasma sintering (SPS) technique. Effects of milling time on phase transformation, structural characteristics, and magnetic properties of powders were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and physical property measure system (PPMS), respectively. Results show that nanostructured α-Fe supersaturated solid solution is obtained in the final MAed products. The saturation magnetization (Ms) increased with increasing milling time and became constant at 130 h, but the coercivity (Hc) increased firstly and then decreased. The consolidated bulk sample exhibited a high density of 6.893 g·cm-3, there was no phase change during SPS process, and the saturation magnetization and susceptibility of the SPSed bulk sample improved in comparison with the milled powders. The variation of magnetic parameters can be explained by nano-scale effect and Herzer model.

关键词： mechanical alloying nanostructured materials sintering magnetization

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WEAR AND SEALING CHARACTERISTICS OF ENGINE VALVE GUIDE

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Chinese Journal of Mechanical Engineering 2005年第3期18卷 434-438页

作者： Qu Shengguan Xia Wei Han Lifa xiao zhiyu Chen Weiping LiYuanyuan College of Mechanical Engineering South China University of Technology Guangzhou 510640 China

A novel powder metallurgy （P/M） material with high wear resistance is developed in order to decrease the wear and lubricant-leakage of a diesel engine valve guide. The friction and wear tests of this material are conducted. It indicates that the wear resistance of the newly developed P/M material has been improved and much better than that of the formerly used alloy steel. Moreover, three different sealing structures are designed and theoretically analyzed with respect to the characteristic of hydrodynamic sealing. Through comparative experiments of component leakage and engine run-in for different valve guide structures, it proves that the structure with a machined sealing groove but not installed with a seal-ring cannot only reduce the specific lubricant consumption （SLC） of cylinder head, but also decrease the wear of valve stern and valve guide.

关键词： Engine valve guide Powder metallurgy material Friction and wear Sealing

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结肠癌胰头转移1例

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中华内分泌外科杂志（中英文） 2024年第3期18卷 463-464页

作者：刘琦尧张镰竞王聪敏薛亚丽肖智钰胡月杨冬艳吉林大学中日联谊医院超声科长春130033

原发于结肠癌的胰腺转移瘤在临床上非常少见,关于其影像学表现的报道更少,本文通过报道1例结肠癌胰头转移瘤并重点分析其超声造影表现,以提高临床对该疾病的诊断。

关键词：胰头转移结肠癌超声造影

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汽车覆盖件模具工艺前期流程的优化设计策略分析

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时代汽车 2024年第3期 116-118页

作者：肖志余武汉软件工程职业学院(武汉开放大学) 湖北省武汉市430205

文章通过对汽车覆盖件模具工艺前期流程的优化设计,使汽车覆盖件模具工艺前期流程更加科学合理,提高汽车覆盖件模具的整体性能和使用寿命,同时也能为其他相关行业的发展提供借鉴经验。

关键词：汽车覆盖件模具工艺前期流程优化设计

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改进的基于信任网络和随机游走策略的评分预测模型

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南京理工大学学报 2015年第5期39卷 602-608页

作者：肖志宇翟玉庆东南大学计算机科学与工程学院江苏南京211189 东南大学计算机网络和信息集成教育部重点实验室江苏南京211189

为了提高推荐算法评分预测的准确度,该文在Trust Walker模型的基础上,提出了一个改进的基于信任网络和随机游走策略的评分预测模型——Referential User Walker模型。该模型通过随机游走策略,利用信任网络中的信任朋友对目标物品或与目... 详细信息

为了提高推荐算法评分预测的准确度,该文在Trust Walker模型的基础上,提出了一个改进的基于信任网络和随机游走策略的评分预测模型——Referential User Walker模型。该模型通过随机游走策略,利用信任网络中的信任朋友对目标物品或与目标物品相似的物品的评分进行评分预测,并在信任网络中找到最可信的Top N评分参考用户,同时引入信任度权重,降低了噪声数据的影响。实验结果表明,与Trust Walker模型相比,Referential User Walker模型的评分预测准确度有所提高。

关键词：推荐信任网络随机游走评分预测 TrustWalker 用户相似度 Top N 评分参考用户

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