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Joint Beam Scheduling and Power Optimization for Beam Hopping LEO Satellite Systems

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China Communications 2024年第10期21卷 226-239页

作者： Zheng Shuang zhang xing Wang Peng Wang Wenbo Key Laboratory of Universal Wireless Communication Ministry of EducationSchool of Information and Communication EngineeringBeijing University of Posts and TelecommunicationsBeijing 100876China

Low earth orbit(LEO) satellite communications can provide ubiquitous and reliable services,making it an essential part of the Internet of Everything network. Beam hopping(BH) is an emerging technology for effectively addressing the issue of low resource utilization caused by the non-uniform spatio-temporal distribution of traffic demands. However, how to allocate multi-dimensional resources in a timely and efficient way for the highly dynamic LEO satellite systems remains a challenge. This paper proposes a joint beam scheduling and power optimization beam hopping(JBSPO-BH) algorithm considering the differences in the geographic distribution of sink nodes. The JBSPO-BH algorithm decouples the original problem into two sub-problems. The beam scheduling problem is modelled as a potential game,and the Nash equilibrium(NE) point is obtained as the beam scheduling strategy. Moreover, the penalty function interior point method is applied to optimize the power allocation. Simulation results show that the JBSPO-BH algorithm has low time complexity and fast convergence and achieves better performance both in throughput and fairness. Compared with greedybased BH, greedy-based BH with the power optimization, round-robin BH, Max-SINR BH and satellite resource allocation algorithm, the throughput of the proposed algorithm is improved by 44.99%, 20.79%,156.06%, 15.39% and 8.17%, respectively.

关键词： beam hopping interior point method potential game resource allocation

Early diagnostic strategies for colorectal cancer

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World Journal of Gastroenterology 2024年第33期30卷 3818-3822页

作者： Shi-cai Liu Han zhang School of Medical Information Wannan Medical CollegeWuhu 241002Anhui ProvinceChina School of Basic Medical Sciences Wannan Medical CollegeWuhu 241002Anhui ProvinceChina

At present,cancer is still an important factor threatening human *** cancer(CRC)is one of the top three most common cancers worldwide and one of the deadliest malignancies in *** latest data showed that CRC incidence and mortality rank third and second,respectively,among global *** and accurate diagnosis is crucial to reduce the morbidity,mortality and improve survival of patients with CRC,but the current early diagnostic methods have *** effectiveness and compliance of diagnostic methods have a certain impact on whether people choose *** this editorial,we explore strategies for the early diagnosis of CRC,including stool-based,blood-based,direct visualization,and imaging examinations.

关键词： Colorectal cancer Diagnostic markers Colonoscopy Fecal immunochemical test Fecal occult blood test Circulating tumor cells Circulating tumor DNA

Numerical Study on Reduction in Aerodynamic Drag and Noise of High-Speed Pantograph

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 2155-2173页

作者： Deng Qin xing Du Tian Li Jiye zhang State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China School of Electrical Engineering Southwest Jiaotong UniversityChengdu610031China

Reducing the aerodynamic drag and noise levels of high-speed pantographs is important for promoting environmentally friendly,energy efficient and rapid advances in train *** computational fluid dynamics theory and the K-FWH acoustic equation,a numerical simulation is conducted to investigate the aerodynamic characteristics of high-speed pantographs.A component optimization method is proposed as a possible solution to the problemof aerodynamic drag and noise in high-speed *** results of the study indicate that the panhead,base and insulator are the main contributors to aerodynamic drag and noise in high-speed ***,a gradual optimization process is implemented to improve the most significant components that cause aerodynamic drag and *** optimizing the cross-sectional shape of the strips and insulators,the drag and noise caused by airflow separation and vortex shedding can be *** aerodynamic drag of insulator with circular cross section and strips with rectangular cross section is the *** insulators and optimizing the chamfer angle and height of the windward surface of the strips can improve the aerodynamic performance of the *** addition,the streamlined fairing attached to the base can eliminate the complex flow and shield the radiated *** contrast to the original pantograph design,the improved pantograph shows a 21.1%reduction in aerodynamic drag and a 1.65 dBA reduction in aerodynamic noise.

关键词： High-speed pantograph aerodynamic drag aerodynamic noise reduction optimizing

Intelligent secure near-field communication

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Science China(Information Sciences) 2024年第9期67卷 340-341页

作者： Nan zhang Jifa zhang Chengwen xing Na DENG Nan ZHAO School of Information and Communication Engineering Dalian University of Technology School of Information and Electronics Beijing Institute of Technology

The research and development efforts for the sixth generation(6G) wireless communication are underway to fulfill the growing demands for wireless communications. 6G is expected to become the key enabler for diverse new applications and services [1]. To achieve the excellent performance, 6G will implement extremely large-scale antenna arrays(ELAAs), terahertz [2], and new types of antennas with metamaterials, leading to a paradigm shift for the electromagnetic characteristics.

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Theoretical understanding of correlation between magnetic phase transition and the superconducting dome in high-Tc cuprates

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 167-173页

作者： Chen zhang cai-Xin zhang Su-Huai Wei Haiqing Lin Hui-Xiong Deng State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Beijing Computational Science Research Center Beijing 100193China

Many issues concerning the origin of high-temperature superconductivity(HTS)are still under *** example,how the magnetic order varies with doping and its relationship with the superconducting temperature(Tc);and why Tcalways peaks near the quantum critical *** this paper,taking hole-doped La_(2)CuO_(4)as a classical example,we employ the first-principles band structure and total energy calculations with Monte Carlo simulations to explore how the symmetry-breaking magnetic ground state evolves with hole doping and the origin of a dome-shaped superconductivity region in the phase *** demonstrate that the local antiferromagnetic order and doping play key roles in determining the electron-phonon coupling,thus ***,the La_(2)CuO_(4)possesses a checkerboard local antiferromagnetic ground *** the hole doping increases,Tcincreases with the enhanced electron-phonon coupling *** as the doping increases further,the strength of the antiferromagnetic interaction weakens and spin fluctuation *** the critical doping level,a magnetic phase transition occurs that reduces the local antiferromagnetism-assisted electron-phonon coupling,thus diminishing the *** superconductivity disappears in the heavily overdoped region when the ferromagnetic order *** observations could account for why cuprates have a dome-shaped superconductivity region in the phase *** study,thus,contributes to a fundamental understanding of the correlation between doping,local magnetic order,and superconductivity of HTS.

关键词： high-temperature superconductivity antiferromagnetic order electron-phonon coupling doping effect cuprates

Characterization and quantification of multi-field coupling in lithium-ion batteries under mechanical constraints

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Journal of Energy Chemistry 2024年第8期95卷 364-379,I0009页

作者： Xue cai caiping zhang Zeping Chen Linjing zhang Dirk Uwe Sauer Weihan Li National Active Distribution Network Technology Research Center Beijing Jiaotong UniversityBeijing 100044China Chair for Electrochemical Energy Conversion and Storage Systems Institute for Power Electronics and Electrical Drives(ISEA)RWTH Aachen UniversityCampus Boulevard 8952074 AachenGermany Center for Ageing Reliability and Lifetime Prediction of Electrochemical and Power Electronic Systems(CARL)Campus-Boulevard 8952074 AachenGermany Juelich Aachen Research Alliance JARA-EnergyAachenGermany Helmholtz Institute Münster(HI MS) IEK-12Forschungszentrum JülichGermany

The safety and durability of lithium-ion batteries under mechanical constraints depend significantly on electrochemical,thermal,and mechanical fields in *** and quantifying the multi-field coupling behaviors requires interdisciplinary ***,we design experiments under mechanical constraints and introduce an in-situ analytical framework to clarify the complex interaction mechanisms and coupling degrees among multi-physics *** proposed analytical framework integrates the parameterization of equivalent models,in-situ mechanical analysis,and quantitative assessment of coupling *** results indicate that the significant impact of pressure on impedance at low temperatures results from the diffusion-controlled step,enhancing kinetics when external pressure,like 180 to 240 k Pa at 10℃,is *** diversity in control steps for the electrochemical reaction accounts for the varying impact of pressure on battery performance across different *** thermal expansion rate suggests that the swelling force varies by less than 1.60%per unit of elevated temperature during the lithiation *** introducing a composite metric,we quantify the coupling correlation and intensity between characteristic parameters and physical fields,uncovering the highest coupling degree in electrochemical-thermal *** results underscore the potential of analytical approaches in revealing the mechanisms of interaction among multi-fields,with the goal of enhancing battery performance and advancing battery management.

关键词： Lithium-ion battery Muti-field coupling Mechanical constraints Interaction mechanisms Quantitative analysis

Iron single-atom/clusters catalysts derived from iron-rich Enteromorpha after urea-saturation for Fenton-like reaction

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Chinese Chemical Letters 2024年第3期35卷 149-152页

作者： Yujie zhang Siyi Liu Dongdong Chen xing Xu School of Environmental Science and Engineering Shandong UniversityQingdao 266237China

Fabrication of single atom catalysts(SACs)by a green and gentle method is important for their practical Fenton-like *** this work,a high effective iron-based catalyst was prepared from the iron-rich Enteromorpha for NPX degradation via peroxymonosulfate(PMS).Both Fe-SACs and iron-clusters was fabricated from the intrinsic iron element in Enteromorpha after the urea *** Fe-SACs/clusters can achieve 100%of NPX oxidation within 20 min with the k_(obs)of 0.282 min^(-1).Quenching tests indicated that the radical pathways were not dominated in the catalytic systems,and strong electron transfer process can be induced in the Fe-SACs/clusters+PMS system by using the NPX as electron donor and FeSACs/clusters/PMS^*complexes as electron *** result was consistent with the phenomenon observed in the galvanic oxidation *** addition,the Fe-SACs/clusters was deposited onto the ceramic membrane(CM)by the spraying-crosslinking process to form a Fe-SACs/clusters@CM,which showed an effective and continuous NPX degradation in a heterogeneous PMS system.

关键词： SACs Iron Clusters Fenton-like reaction Enteromorpha

Intrinsic lithiophilic carbon host derived from bacterial cellulose nanofiber for dendrite-free and long-life lithium metal anode

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Nano Research 2024年第5期17卷 4203-4210页

作者： Gangyi Xiong Jiayu Yu Yalan xing Puheng Yang Shichao zhang School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Physics Science and Nuclear Energy Engineering Beihang UniversityBeijing 100191China

Although lithium metal is considered a promising anode for advanced Li-S and Li-air batteries,the uncontrolled dendrite growth and infinite volume change impede its practical ***,we report an ideal framework composed of carbonized bacterial cellulose(CBC)nanofibers,which shows intrinsic lithiophilicity to molten lithium without any lithiophilic surface *** wetting behavior of molten lithium can be significantly improved because its surface functional groups provide thermodynamical driving force,and the high surface roughness derived from nanocracks leads to rapid infusion in *** hybrid anode exhibits long cycle life up to 2000 h and excellent deep stripping-platting capacity up to 20 mAh·cm^(-2).When the anode is assembled with LiFePO_(4) cathode,the full cell delivers a good cycling stability up to 700 *** is attributed to the intrinsic lithiophilic scaffold,which can not only lower the nucleation barrier of Li and provide uniform nucleation sites for stable Li stripping/plating,but also offer interspace to accommodate volume fluctuation of lithium during long *** work provides a new manner to achieve a series of intrinsic lithiophilic carbon skeletons based on the large family of biomass materials and organic materials.

关键词： intrinsic lithiophilicity lithium metal anode bacterial cellulose lithium dendrite long cycling life

First-Arrival Picking Method for Active Source Data with Ocean Bottom Seismometers Based on Spatial Waveform Variation Characteristics

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Journal of Ocean University of China 2024年第4期23卷 970-980页

作者： LIU Hongwei xing Lei ZHU Henghua zhang Jin zhang Jing LIU Huaishan Key Laboratory of Submarine Geosciences and Prospecting Techniques Ministry of EducationCollege of Marine GeosciencesOcean University of ChinaQingdao 266100China Laboratory for Marine Mineral Resources Qingdao Marine Science and Technology CenterQingdao 266071China College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China Shandong Institute of Geological Survey Jinan 250014China

The precision and reliability of first-arrival picking are crucial for determining the accuracy of geological structure inversion using active source ocean bottom seismometer(OBS)refraction *** methods for first-arrival picking based on sample points are characterized by theoretical errors,especially in low-sampling-frequency OBS data because the travel time of seismic waves is not an integer multiple of the sampling *** this paper,a first-arrival picking method that utilizes the spatial waveform variation characteristics of active source OBS data is ***,the distribution law of theoretical error is examined;adjacent traces exhibit variation characteristics in their ***,a label cross-correlation superposition method for extracting highfrequency signals is presented to enhance the first-arrival picking *** from synthetic and field data verify that the proposed approach is robust,successfully overcomes the limitations of low sampling frequency,and achieves precise outcomes that are comparable with those of high-sampling-frequency data.

关键词： first-arrival picking spatial waveform variation label cross-correlation superposition method