检索结果-内蒙古大学图书馆

Innentitelbild: Mechanistic Understanding of Efficient Polyethylene Hydrocracking over Two-Dimensional Platinum-Anchored Tungsten Trioxide (Angew. Chem. 40/2023)

引用

Angewandte Chemie 2023年第40期135卷

作者： Qimin Zhou Dr. Deliang Wang Prof. Dr. Qingyue Wang Dr. Kailin He Prof. Dr. Khak Ho Lim Prof. Dr. Xuan Yang Prof. Dr. Wen-Jun Wang Prof. Dr. Bo-Geng Li Prof. Dr. Pingwei Liu State Key Laboratory of Chemical Engineering College of Chemical and Biological Engineering Zhejiang University 866 Yuhangtang Rd Hangzhou 310027 Zhejiang P. R. China Institute of Zhejiang University-Quzhou 99 Zheda Rd Quzhou 324000 Zhejiang P. R. China Key Laboratory of Hunan Province for the Synergetic Control and Resource Reuse of the Multi-Pollutants of Flue Gas National Sintering and Pelletizing Equipment System Engineering Research Center Zhongye Changtian International Engineering Co. Ltd. Changsha 410205 Hunan P. R. China

来源：评论

学校读者我要写书评

暂无评论

Inside Cover: Mechanistic Understanding of Efficient Polyethylene Hydrocracking over Two-Dimensional Platinum-Anchored Tungsten Trioxide (Angew. Chem. Int. Ed. 40/2023)

引用

Angewandte Chemie International Edition 2023年第40期62卷

来源：评论

学校读者我要写书评

暂无评论

research on Integrated Navigation Algorithm Based on Radial Basis Function Neural Network

引用

Journal of Physics: Conference Series 2021年第1期1961卷

作者： Hang Liu Kaicheng Li Qiang Fu Lei Yuan The National Engineering Research Center for Rail Transportation Operation Control System Beijing Jiaotong University Beijing 100044 P.R. China The State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing 100044 P.R. China

The Qinghai-Tibet Railway is located on the Qinghai-Tibet Plateau in China. Due to its harsh climatic conditions and geographic environment, the line currently uses the Global Position system (GPS) to achieve train positioning. However, the navigation satellites are easily blocked by obstructions such as tunnels, resulting in a decrease in positioning accuracy. The conventional solution is to use multiple sensors such as an inertial navigation system (INS) for data fusion. But in the INS/GPS integrated navigation system, when the GPS signal is lost, the navigation accuracy will still decrease. In order to solve this problem, this paper proposes a radial basis function (RBF) neural network-assisted integrated navigation filtering algorithm. When the two systems are working normally, the measured raw information is used to train the RBF neural network. When the GPS fails, the measured and calculated values of the inertial navigation system are input to the trained network model to obtain the predicted error value, which is corrected to the inertial navigation system to obtain the final navigation information. The MATLAB simulation results show that when the short-term GPS information is missing, the integrated navigation system assisted by the RBF neural network has better estimation accuracy.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Channel Characterization for Vehicle-to-Infrastructure Communications at the Terahertz Band

Channel Characterization for Vehicle-to-Infrastructure Commu...

引用

IEEE International Conference on Communications Workshops, ICC

作者： Haofan Yi Ke Guan Bo Ai Danping He Fusheng Zhu Jianwu Dou Zhangdui Zhong State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China Beijing Engineering Research Center of High-speed Railway Broadband Mobile Communications Beijing China Guangdong Communications & Networks Institute Guangzhou China Wireless Algorithm Department Product R&D system ZTE Corporation Shenzhen China

ISBN: (数字)9781728174402

ISBN: (纸本)9781728174419

Although the vehicular communications began from the era of the Long Term Evolution (LTE), the strict requirements of the vehicular safety and advanced applications force the academic and industrial communities to continue the topic on the next-generation vehicular communications. In order to realize extremely high reliability and low latency, the frequency spectrum of terahertz (THz) band with ultra-large bandwidth is likely to be one of the candidates at the age of beyond 5th-generation communications (B5G). In this paper, a measurement-validated self-developed ray-tracing (RT) simulator of Beijing Jiaotong University is utilized to characterize the vehicle-to-infrastructure (V2I) channel at 300-308 GHz in highway scenario. Corresponding channel parameters, in line with the standard channel models, are then fed into the quasi deterministic radio channel generator (QuaDRiGa), which is a 3GPP 38.901 reference implementation. The differences in path loss and root-mean-square (RMS) delay spread between RT and QuaDRiGa are summarized, respectively. The good agreement in the power domain and the time domain indicates that the channel parameters provided in our work can operate well in the standard channel model. These results can be used to guide the design of the future vehicular communications at the THz band.

关键词： Road transportation Decorrelation Channel models Wireless communication Long Term Evolution MIMO communication

来源：评论

学校读者我要写书评

暂无评论

Gradient piezoelectric composites for ultrasonic transducer design and imaging applications

引用

Journal of Materiomics 2025年第6期11卷

作者： Chenxue Hou Zhaoxi Li Chunlong Fei Qibo Lin Xiaofei Luo Xiongwei Wei Yiheng Yang Qi Lu Yi Quan Guangzhi Dong Zeyu Chen Xiaozhou Lü Weimin Bao Yintang Yang Shaanxi Provincial Key Laboratory of Integrated Circuit and System Integration Faculty of Integrated Circuit Xidian University Xi'an 710071 China The State Key Laboratory of Analog and Mixed-Signal VLSl Institute of Microelectronics University of Macau Macao 999078 China School of Aerospace Science and Technology Xidian University Xi'an 710071 China State Key Laboratory of Precision Manufacturing for Extreme Service Performance College of Mechanical and Electrical Engineering Central South University Changsha 410083 China College of Automotive and Mechanical Engineering Changsha University of Science and Technology Changsha 410114 China Hunan Province University Key Laboratory of Intelligent Testing and Control Technology for Engineering Equipment Changsha 410114 China School of Advanced Materials and Nanotechnology Xidian University Xi'an 710126 China Furong Laboratory (Precision Medicine) Changsha 410008 China National Engineering Research Center of Personalized Diagnostic and Therapeutic Technology Xiangya Hospital Central South University Changsha 410008 China Hunan Engineering Research Center of Skin Health and Disease Xiangya Hospital Central South University Changsha 410008 China

Ultrasonic imaging technology has advanced rapidly, the escalating demand for imaging quality has driven the continuous development of ultrasonic transducers featuring high-performance. Among them, the crucial factors constraining the further enhancement of imaging quality are the frequency of the device and the intensity of the echo signal. Piezoelectric composites have become a hotspot for ultrasonic transducers and imaging applications due to their excellent properties. However, due to the limitations of the accuracy of the cutting process, the development of piezoelectric/polymer composites is often undermined by undesirable pseudo-vibrations, especially in high-frequency applications, which will significantly reduce energy conversion efficiency. In this study, a novel design method of 1–3 piezoelectric composites with gradient nanoparticle doped polymer is proposed to eliminate the undesired lateral vibrations. Based on the optimized composites, a high-performance composite ultrasonic transducer with a center frequency of 8.51 MHz is prepared. Compared with the traditional composite transducer, the optimized transducer improves the echo voltage amplitude significantly, reaching nearly 3 times. The above advantages are further verified in high-quality ultrasound and photoacoustic imaging. The optimization method has valuable guidance for the design of high-frequency composite transducers, which have great potential in ultrasonic and photoacoustic imaging applications.

关键词： Piezoelectric composites Ultrasonic transducer Imaging applications Lateral vibration Finite element analysis

来源：评论

学校读者我要写书评

暂无评论

Fault Diagnosis of the On-board Equipment in CTCS-3 Based on Timed Automata and Mutation Theoy

Fault Diagnosis of the On-board Equipment in CTCS-3 Based on...

引用

International Conference on Intelligent Transportation

作者： Zhuolin Hu Tao Tang Wanli Lu Wei Zheng Jidong Lv Shigen Gao Shuai Su State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China National Engineering Research Center of Rail Transportation Operation and Control System Beijing Jiaotong University Beijing China

ISBN: (纸本)9781538670255

In this paper, a method of fault diagnosis for the on-board equipment based on Timed Automata (TA) and mutation theory is proposed. Firstly, several kinds of mutation operators were injected in TA model to get Fault Timed Automta (FTA), in which the fault with timed features is described. Secondly, the approach of fault diagnosis and the verification of the diagnosability were proposed by parallel product A, in which the necessary and sufficient conditions of fault diagnosiability were discussed. Finally, we take the Ceiling Speed Monitoring (CSM) and Target Speed Monitoring (TSM) functions as a case study to present the feasibility of the method. Based on the CSM diagnoser, the fault set with events and time behaviors was effectively divided into two categories: diagnosable and non-diagnosable. The result is shown that the fault diagnosis and verification of diagnosability can be performed and it is of great significance for fault diagnosis of the on-board equipment.

关键词： Fault diagnosis Delays Automata Delay effects Clocks Real-time systems Monitoring

来源：评论

学校读者我要写书评

暂无评论

Multiple residual dense networks for reconfigurable intelligent surfaces cascaded channel estimation

arXiv

引用

arXiv 2021年

作者： Jin, Yu Zhang, Jiayi Huang, Chongwen Yang, Liang Xiao, Huahua Ai, Bo Wang, Zhiqin The School of Electronic and Information Engineering Beijing Jiaotong University Beijing100044 China The Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong University Beijing100044 China Zhejiang Provincial Key Lab of Information Processing Communication and Networking Zhejiang University Hangzhou310007 China College of Computer Science and Electronic Engineering Hunan University Changsha410082 China ZTE Corporation State Key Laboratory of Mobile Network Mobile Multimedia Technology Shenzhen518057 China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing100044 China Henan Joint International Research Laboratory of Intelligent Networking and Data Analysis Zhengzhou University Zhengzhou450001 China Research Center of Networks and Communications Peng Cheng Laboratory Shenzhen518055 China China Academy of Information and Communications Technology Beijing100191 China

Reconfigurable intelligent surface (RIS) constitutes an essential and promising paradigm that relies programmable wireless environment and provides capability for space-intensive communications, due to the use of low-cost massive reflecting elements over the entire surfaces of man-made structures. However, accurate channel estimation is a fundamental technical prerequisite to achieve the huge performance gains from RIS. By leveraging the low rank structure of RIS channels, three practical residual neural networks, named convolutional blind denoising network, convolutional denoising generative adversarial networks and multiple residual dense network, are proposed to obtain accurate channel state information, which can reflect the impact of different methods on the estimation performance. Simulation results reveal the evolution direction of these three methods and reveal their superior performance compared with existing benchmark schemes. Copyright © 2021, The Authors. All rights reserved.

关键词： Channel estimation

来源：评论

学校读者我要写书评

暂无评论

INTRODUCTION

引用

Bulletin of the American Meteorological Society 2024年第8期105卷 S1-S11页

作者： Boyer, T. Blunden, J. Dunn, R.J.H. NOAA/NESDIS National Centers for Environmental Information Silver Spring Maryland NOAA/NESDIS National Centers for Environmental Information Asheville North Carolina Met Office Hadley Centre Exeter United Kingdom European Centre for Medium-Range Weather Forecasts Reading United Kingdom University of Maryland College Park Maryland Scripps Institution of Oceanography University of California San Diego La Jolla California NOAA/NWS National Centers for Environmental Prediction Climate Prediction Center College Park Maryland Brandenburg University of Technology (BTU) Cottbus-Senftenberg Germany Servicio Meteorológico Nacional Buenos Aires Argentina NOAA/OAR Physical Sciences Laboratory Boulder Colorado European Centre for Medium-Range Weather Forecasts Bonn Germany Center for Geophysical Research and School of Physics University of Costa Rica San José Costa Rica Department of Meteorology and National Centre for Earth Observation University of Reading Reading United Kingdom Centro Nacional de Monitoramento e Alertas de Desastres Naturais CEMADEN São Paulo Brazil Université Grenoble Alpes Institut des Géosciences de l’Environnement IRD CNRS Grenoble INP Grenoble France Hampton University Hampton Virginia Seychelles Meteorological Authority Mahe Seychelles Section for Glaciers Ice and Snow Norwegian Water Resources and Energy Directorate Oslo Norway National Research Institute for Agriculture Food and Environment (INRAE) CARRTEL Université Savoie Mont Blanc Thonon les Bains France Graduate School of Agriculture Osaka Metropolitan University Sakai Japan Science Faculty Universidad Nacional de Colombia Bogotá Colombia University of Bremen Bremen Germany NOAA Global Monitoring Laboratory Boulder Colorado Servicio Nacional de Meteorología e Hidrología del Perú Lima Perú Centro de Investigaciones sobre Desertificación – Spanish National Research Council (CSIC-UV-GVA) Valencia Spain Hydro-Climate Extremes Lab (H-CEL) Ghent University Ghent Belgium Department o

In 2023, La Niña conditions that generally prevailed in the eastern Pacific Ocean from mid-2020 into early 2023 gave way to a strong El Niño by October. Atmospheric concentrations of Earth’s major greenhouse gases—carbon dioxide, methane, and nitrous oxide—all increased to record-high levels. The annual global average carbon dioxide concentration in the atmosphere rose to 419.3±0.1 ppm, which is 50% greater than the pre-industrial level. The growth from 2022 to 2023 was 2.8 ppm, the fourth highest in the record since the 1960s. The combined short-term effects of El Niño and the long-term effects of increasing levels of heat-trapping gases in the atmosphere contributed to new records for many essential climate variables reported here. The annual global temperature across land and oceans was the highest in records dating as far back as 1850, with the last seven months (June–December) having each been record warm. Over land, the globally averaged temperature was also record high. Dozens of countries reported record or near-record warmth for the year, including China and continental Europe as a whole (warmest on record), India and Russia (second warmest), and Canada (third warmest). Intense and widespread heatwaves were reported around the world. In Vietnam, an all-time national maximum temperature record of 44.2°C was observed at Tuong Duong on 7 May, surpassing the previous record of 43.4°C at Huong Khe on 20 April 2019. In Brazil, the air temperature reached 44.8°C in Araçuaí in Minas Gerais on 20 November, potentially a new national record and 12.8°C above normal. The effect of rising temperatures was apparent in the cryosphere, where snow cover extent by June 2023 was the smallest in the 56-year record for North America and seventh smallest for the Northern Hemisphere overall. Heatwaves contributed to the greatest average mass balance loss for Alpine glaciers around the world since the start of the record in 1970. Due to rapid volume loss beginning in 2021, St. A

关键词：

来源：评论

学校读者我要写书评

暂无评论

Lattice Evolution, Ordering Transformation and Microwave Dielectric Properties of Rock-Salt Li3+xMg2-2xNb1-XTi2xO6 Solid-Solution system: A Newly Developed Pseudo Ternary Phase Diagram

SSRN

引用

SSRN 2020年

作者： Zhang, Xing Zhang, Xiao Fang, Zixuan Yang, Hongyu Xiong, Zhe Yang, Hongcheng Zhang, Shuren Tang, Bin State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Chengdu610054 China National Engineering Research Center of Electromagnetic Radiation Control Materials University of Electronic Science and Technology of China Chengdu610054 China China Key System & Integrated Circuit Co. Ltd. Wuxi214035 China

The new types of multi-component Li3+xMg2-2xNb1-xTi2xO6 (0≤x≤1) solid-solution ceramics were designed based on the Li2TiO3-Li3NbO4-MgO pseudo ternary phase diagram and studied for millimeter-wave applications. The ceramics showed a full range of solid solubility between the Li3Mg2NbO6 and Li2TiO3 endmembers. As the doping content (x) increased, we detected the phase transitions among the orthorhombic, cubic, and monoclinic phase driven by the compositional changes, as well as accompanied with an order-disorder-order transformation. Besides, the smooth orthorhombic-cubic phase transition interfaces were observed in the electron diffraction images for the sample with the low dopant concentration (x=0.2), and the reconstructed superlattices based on the orthorhombic or the cubic structure were both observed nearby the orthorhombic-cubic phase transition interface. The change of Q×f values showed a considerable increase with the emergence of the superlattices, and the enhancement of the Q×f values was related to the very small lattice vibrational anharmonicity in the structures that contain the reconstructed superlattices. Typically, when sintered at 1250 ℃ for 4 h, the ultra-low dielectric loss was achieved in the x=0.2 sample with the properties of εr=16.1, Q×f=128,600 GHz (f=9.2 GHz) and τf=-30.4 ppm/℃, and the temperature stable properties were obtained in the x=0.9 sample with εr=20.4, Q×f=90,300 GHz (f=7.9 GHz), and τf=2.9 ppm/℃. © 2020, The Authors. All rights reserved.

关键词： Lithium compounds

来源：评论

学校读者我要写书评

暂无评论

Construction of an example system for AC/DC hybrid power grid with high-proportion renewable energy

Construction of an example system for AC/DC hybrid power gri...

引用

作者： Zhao, Dawei Ma, Jin Qian, Minhui Zhu, Lingzhi Yao, Liangzhong Ding, Kun Han, Hualing State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Changping District Beijing China State Key Laboratory of Operation and Control of Renewable Energy and Storage Systems Jiangsu Engineering Technology Research Center for Energy Storage Conversion and Application China Electric Power Research Institute Gulou District Nanjing China Wind Power Technology Center of Gansu Electric Power Company Qilihe District Lanzhou China

Large-scale wind and solar power generations have got rapid development in recent years in China and abroad. They always connect to load centres through high-voltage direct current (HVDC) transmission or ultra HVDC (UHVDC) transmission lines. Such systems are so large and it is necessary to make appropriate equivalence according to the purpose of different research. At present, the analysis model of this kind of real system is few, and simplified single-machine infinite-bus system or IEEE example system is adopted most of the time, which may affect the accuracy of analysis results. Here, the UHVDC project from a practical renewable energy base to load centres in China is chosen as an example, the actual structure and parameters are used to establish a typical example system for AC/DC hybrid power grid with high-proportion renewable energy. The new-generation synchronous condenser with large capacity and the supporting synchronous generators are all considered. First, the installed power generation, power grid structure, and load configuration of example system are introduced. Then the load flow distribution and transient stability characteristics are analysed by using DIgSILENT PowerFactory software. Finally, the feasibility of the proposed example system is shown by simulation results. © 2019 Institution of engineering and *** right reserved.

关键词： Electric load flow

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：