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Control of temperature dependent viscosity for manufacturing of Bi-doped active fiber

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International Journal of Extreme Manufacturing 2024年第3期6卷 522-530页

作者： Rui Duan Jingfei Chen Hao Ke Tianxia Wei Ke Zhang Xueliang Li Xu Feng Qiuju Zheng Zhixue He Jianrong Qiu Shifeng Zhou State Key Laboratory of Luminescent Materials and Devices School of Materials Science and EngineeringSouth China University of TechnologyGuangzhou 510640People’s Republic of China Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques Guangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and DevicesGuangzhou 510640People’s Republic of China School of Materials Science and engineering Qilu University of TechnologyJinanPeople’s Republic of China Peng Cheng Laboratory Shenzhen 518000People’s Republic of China College of Optical Science and engineering State Key Laboratory of Modern Optical InstrumentationZhejiang UniversityHangzhou 310027People’s Republic of China

Bi-activated photonic materials are promising for various applications in high-capacity telecommunication,tunable laser,and advanced bioimaging and *** various Bi-doped material candidates have been explored,manufacturing of Bi heavily doped fiber with excellent optical activity remains a long-standing ***,a novel viscosity evolutional behavior mediated strategy for manufacturing of Bi-doped active fiber with high dopant solubility is *** intrinsic relation among the evolution of Bi,reaction temperature and viscosity of the glass system is ***,the effective avenue to prevent the undesired deactivation of Bi during fiber drawing by tuning the temperature dependent viscosity evolution is *** applying the strategy,for the first time we demonstrate the success in fabrication of heavily doped Bi active ***,the principal fiber amplifier device is constructed and broadband optical signal amplification is *** findings indicate the effectiveness of the proposed temperature dependent viscosity mediated strategy for developing novel photonic active fiber,and they also demonstrate the great potential for application in the next-generation high-capacity telecommunication system.

关键词： infrared luminescence active fiber optical amplification

FMHADP: Design of an Efficient Pre-Forensic Layer for Mitigating Hybrid Attacks via Deep Learning Pattern Analysis

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Journal of Harbin institute of technology(New series) 2024年

作者： Meesala Sravani B Kiran Kumar M Rekha Sundari D Tejaswi Department of Computer Science and engineering， GMR institute of technology Information technology， Anil Neerukonda institute of technology & Science(Autonomous)

Network attack detection and mitigation require packet collection， pre-processing， feature analysis， classification， and post-processing. Models for these tasks sometimes become complex or inefficient when applied to real-time data samples. To mitigate hybrid assaults， this study designs an efficient forensic layer employing deep learning pattern analysis and multidomain feature extraction. In this paper， we provide a novel multidomain feature extraction method using Fourier， Z， Laplace， Discrete Cosine Transform (DCT)， 1D Haar Wavelet， Gabor， and Convolutional Operations. Evolutionary method dragon fly optimisation reduces feature dimensionality and improves feature selection accuracy. The selected features are fed into VGGNet and GoogLeNet models using binary cascaded neural networks to analyse network traffic patterns， detect anomalies， and warn network administrators. The suggested model tackles the inadequacies of existing approaches to hybrid threats， which are growing more common and challenge conventional security measures. Our model integrates multidomain feature extraction， deep learning pattern analysis， and the forensic layer to improve intrusion detection and prevention systems. In diverse attack scenarios， our technique has 3.5% higher accuracy， 4.3% higher precision， 8.5% higher recall， and 2.9% lower delay than previous models.

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Spatiotemporal variations in ecosystem services and their trade-offs and synergies against the background of the gully control and land consolidation project on the Loess Plateau,China

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Journal of Arid Land 2024年第1期16卷 131-145页

作者： WANG Jing WEI Yulu PENG Biao LIU Siqi LI Jianfeng Key Laboratory of Degraded and Unused Land Consolidation engineering Ministry of Natural and ResourcesXi'an 710075China institute of Land engineering and technology Shaanxi Provincial Land Engineering Construction Group Co.Ltd.Xi'an 710021China School of Human Settlements and Civil engineering Xi'an Jiaotong UniversityXi'an 710049China Shaanxi Key Laboratory of Land Consolidation Xi'an 710064China

Studying the spatiotemporal variations in ecosystem services and their interrelationships on the Loess Plateau against the background of the gully control and land consolidation(GCLC)project has significant implications for ecological protection and quality development of the Yellow River ***,in this study,we took Yan'an City,Shaanxi Province of China,as the study area,selected four typical ecosystem services,including soil conservation service,water yield service,carbon storage service,and habitat quality service,and quantitatively evaluated the spatiotemporal variation characteristics and trade-offs and synergies of ecosystem services from 2010 to 2018 using the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)*** also analysed the relationship between the GCLC project and regional ecosystem service changes in various regions(including 1 city,2 districts,and 10 counties)of Yan'an City and proposed a coordinated development strategy between the GCLC project and the ecological *** results showed that,from 2010 to 2018,soil conservation service decreased by 7.76%,while the other three ecosystem services changed relatively little,with water yield service increasing by 0.56% and carbon storage service and habitat quality service decreasing by 0.16% and 0.14%,*** ecological environment of Yan'an City developed in a balanced way between 2010 and 2018,and the four ecosystem services showed synergistic relationships,among which the synergistic relationships between soil conservation service and water yield service and between carbon storage service and habitat quality service were *** GCLC project had a negative impact on the ecosystem services of Yan'an City,and the impact on carbon storage service was more *** study provides a theoretical basis for the scientific evaluation of the ecological benefits of the GCLC project and the realization of a win-win situation between food security and e

关键词： ecosystem services trade-offs and synergies gully control and land consolidation habitat quality Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model Loess Plateau

Effects of calendering state on coupled electrochemical-mechanical performance of silicon based composite electrodes

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Green Energy and Intelligent Transportation 2024年第5期3卷 34-41页

作者： Dawei Li Hongfei Wan Jiahui Liu Hainan Jiang Yikai Wang Junqian Zhang Yuejiu Zheng School of Mechanical engineering University of Shanghai for Science and TechnologyShanghai 200093China Department of engineering Physics Tsinghua UniversityBeijing100084China Department of Chemical and Materials engineering University of KentuckyLexingtonKY 40506USA Shanghai institute of Applied Mathematics and Mechanics School of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China

The super volume changes and severe mechanical degradation have been a hindrance in the wide application of silicon based composite electrodes in commercial lithium-ion batteries(LIBs).Calendering,one procedure in producing LIBs'electrodes,is indispensable to ensure low porosity and energy ***,the repercussions of the calendering process on the physical characteristics related to the behavior of silicon(Si)based electrodes during the electrochemical reaction have not been well ***,on account of the deformation characteristic of cantilever electrodes,an in-situ technique is employed to analyze the repercussions of calendering status on the coupled electro-chemo-mechanical *** the electrochemical cycling,Young's modulus and diffusion-induced stress in composite electrodes are *** results show that the swelling strain,the stress and the modulus of the Si-based electrode and the calendering degree are positively ***,the stress induced by diffusion in the active layer tends to increase in the stage of lithiation and reverses during the delithiation *** with the SEM analysis,we conclude that the calendering process can induce larger stress,driving the formation of cracks in *** findings can help understand how the calendering process could affect the capacity dissipating and lifetime of Si based electrodes.

关键词： Calendering degree In situ measurement Coupled electro-mechan-chemical properties Si composite electrode Stress evolution

Performance analysis of the tight combination of GPS, BDS, GALILEO, and QzsS mixed frequencies signals

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Geodesy and Geodynamics 2024年第4期15卷 366-378页

作者： Yu Han Fangjun Qin Xugang Lian Shengliang Wang Leiyuan Qian Wenhua Huang College of Electrical engineering Naval University of EngineeringWuhan 430033China College of Mining engineering Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Satellite Navigation System and Equipment technology Shijiazhuang 050081China State Key Laboratoryof Geodesy and Earth'sDynamics Innovation AcademyforPrecision Measurement Scienceand Technology Chinese Academy of SciencesWuhan 430077China China Energy engineering Group Shanxi Electric Power engineering CO.LTD. Taiyuan 030001China

With the gradual development and modernization of satellite navigation systems,using observation information from multi-GNss has become one of the hot-spot issues in recent ***-system loose combinations form double-difference observation equations within their respective systems,and the positioning effect is ***,the interchangeability and compatible interoperability between global navigation satellite systems(GNSS)cannot be truly *** the same time,when the number of visible satellites decreases abruptly,the positioning performance deteriorates *** paper focuses on the GNsS multi-system tight combination relative positioning technique,gives a mathe-matical model of multi-system tight combination relative positioning considering differential inter-system bias(DISB),and analyzes the time-varying characteristics of DISB at overlapping and non-overlapping frequencies among GPS/Galileo,GPS/BDS,and GPS/QZSS in terms of receiver brand,tem-perature,and receiver *** GNsS tight combination relative positioning performance is verified by static data from Curtin University and dynamic data measured at Taiyuan University of *** results show that compared with loose combination,the ambiguity-fixed rate increases from 62.18%to 97.60%for static data and from 74.97%to 99.53%for dynamic data when the elevation mask angle is 50°,resulting in a significant improvement in positioning performance.

关键词： GNSS Mix frequencies Redundancy Tightcombination Differential inter-system bias

Novel insights into the dehalogenation mechanism and ecotoxicity assessment of 6:2 Cl-PFESA from density functional theory calculations

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Emerging Contaminants 2024年第2期10卷 115-122页

作者： Youxin Xu Chenxi Zhang Zhe Wang Bing Chen Xiaomin Sun Shuguang Wang Huifang Tian institute of Environmental Biotechnology and Functional Materials School of Environmental Science and EngineeringShandong UniversityQingdaoShandong266237China Shandong engineering Laboratory for Clean Utilization of Chemical Resources Weifang University of Science and TechnologyWeifang262700China Northern Region Persistent Organic Pollution Control(NRPOP)Laboratory Faculty of Engineering and Applied ScienceMemorial University of NewfoundlandSt.John'sNLA1B 3X5Canada Environment research institute Shandong UniversityQingdaoShandong266237China Sino-French research institute for Ecology and Environment(ISFREE) Shandong UniversityQingdaoShandong266237China

The electroplating industry is the main source of 6:2 chlorinated polyfluorinated ether sulfonate(6:2 Cl-PFESA)pollution,which presents risks to human health and the *** is therefore crucial to develop effective 6:2 Cl-PFESA degradation *** oxidation is a potential treatment method for 6:2 Cl-PFESA due to its outstanding oxidative degradability following the generation of the sulfate radical(SO_(4)^(•−))and hydroxyl radical(•OH).It has proven difficult to acquire a full understanding of the reaction mechanism and formation of intermediate(IM)products through conventional experimental studies because they are costly and ***,a theoretical analysis method based on density functional theory(DFT)calculations was *** DFT results showed that electron transfer for the degradation of 6:2 Cl-PFESA could be initiated by the protonated sulfate radical(HSO_(4)•,ΔG≠SET=9.16 kcal/mol),rather than SO4•−(ΔG≠SET=41.60 kcal/mol).After desulfonation,the reaction underwent stepwise decarboxylation cycles under the action of•OH,leading to the elimination of the CF_(2) units until there was complete mineralization into HCl,HF,and CO_(2).Furthermore,the IMs and the end products of 6:2 Cl-PFESA were evaluated using ECOSAR and TEST *** low bioaccumulation of the short-chain IMs meant that they could be considered safe in terms of ecotoxicity and health *** research determined the theoretical and mechanistic basis of the effects of persulfate in the treatment of water containing 6:2 Cl-PFESA,and its structural analogues.

关键词： Active free radicals Dehalogenation reaction Degradation mechanisms Theoretical prediction Ecotoxicity assessment

GNSS gyroscopes:determination of angular velocity and acceleration with very high-rate GNSS

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Satellite Navigation 2024年第1期5卷 74-90页

作者： Yun Shi Peiliang Xu Yuanming Shu Xiaolin Meng School of Geomatics Xi’an University of Science and TechnologyXi’an710054People’s Republic of China Disaster Prevention research institute Kyoto UniversityUjiKyoto611-0011Japan College of Marine Geosciences Ocean University of ChinaQingdaoPeople’s Republic of China School of Instrument Science and engineering Southeast UniversityNanjing210096People’s Republic of China

Although global navigation satellite systems(GNSS)have been routinely applied to determine attitudes,there exists no literature on determining angular velocity and/or angular acceleration from *** by the invention of computerized accelerometers of the correspondence author and following the success of accurately recovering translational velocity and acceleration waveforms from very high-rate GNSS precise positioning by Xu and his collaborators in 2021,we propose the concept of GNSS gyroscopes and reconstruct angular velocity and acceleration from very high-rate GNSS attitudes by applying regularization under the criterion of minimum mean squared *** major results from the experiments can be summarized in the following:(i)angular velocity and acceleration waveforms computed by applying the difference methods to high-rate GNSS attitudes are too noisy and can be physically not meaningful and numerically *** same can be said about inertial measurement unit(IMU)attitudes,if IMU gyros are not of very high accuracy;(ii)regularization is successfully applied to reconstruct the high-rate angular velocity and acceleration waveforms from 50 Hz GNSS attitudes and significantly outperforms the difference methods,validating the proposed concept of GNSS *** comparing the angular velocity and acceleration results by using the difference methods and regularization,we find that the peak values of angular velocity and acceleration by regularization are much smaller by a maximum factor of 1.57 in the angular velocity to a maximum factor of 8662.53 times in the angular acceleration in the case of high-rate GNSS,and by a maximum factor of 1.26 in the angular velocity to a maximum factor of 2819.85 times in the angular acceleration in the case of IMU,respectively;and(iii)the IMU attitudes apparently lead to better regularized angular velocity and acceleration waveforms than the high-rate GNSS attitudes,which can well be explained by the fact that the

关键词： Angular velocity Angular acceleration High-rate GNSS GNSS attitudes GNSS gyroscopes Regularization

Enhancing Software Effort Estimation:A Hybrid Model Combining LSTM and Random Forest

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Journal of Harbin institute of technology(New Series) 2024年第4期31卷 42-51页

作者： Badana Mahesh Mandava Kranthi Kiran Department of Computer Science and engineering GITAM Deemed to be UniversityVishakhapatnam 561203India Department of Computer Science and engineering Anil Neerukonda Institute of Technology&SciencesVishakhapatnam 531162India

Effort estimation plays a crucial role in software development projects,aiding in resource allocation,project planning,and risk *** estimation techniques often struggle to provide accurate estimates due to the complex nature of software *** recent years,machine learning approaches have shown promise in improving the accuracy of effort estimation *** study proposes a hybrid model that combines Long Short-Term Memory(LSTM)and Random Forest(RF)algorithms to enhance software effort *** proposed hybrid model takes advantage of the strengths of both LSTM and RF *** evaluate the performance of the hybrid model,an extensive set of software development projects is used as the experimental *** experimental results demonstrate that the proposed hybrid model outperforms traditional estimation techniques in terms of accuracy and *** integration of LSTM and RF enables the model to efficiently capture temporal dependencies and non-linear interactions in the software development *** hybrid model enhances estimation accuracy,enabling project managers and stakeholders to make more precise predictions of effort needed for upcoming software projects.

关键词： software effort estimation hybrid model ensemble learning LSTM temporal dependencies non⁃linear relationships

The exploration and practice of low-altitude airspace flight service and traffic management in China

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Green Energy and Intelligent Transportation 2024年第2期3卷 1-8页

作者： Xiangmin Guan Hongxia Shi Dongsong Xu Binhua Zhang Jian Wei Jun Chen CAAC Key Laboratory of General Aviation Operation Department of General AviationCivil Aviation Management Institute of ChinaBeijing 100102China research institute of Civil Aviation Regulations and Standardization China Academy of Civil Aviation Science and TechnologyBeijing 100028China Department of technology Platform Phoenix Wings Technology(Shen zhen)Co.LtdShenZhen 518054China Shenzhen Highgreat Innovation technology Development Co. Ltd dShenzhen 518000China School of engineering and Materials Science Queen Mary University of LondonLondonE14NSUK

Due to the inherent nature of being highly digitalized,networked and intelligent,Unmanned Aerial System(UAS)operations pose a huge challenge to traditional aviation regulation and technical *** to keep safe,efficient and integrated operation for different Airspace users has become a pressing issue faced by civil aviation around the *** paper focuses on the main operational scenarios and characteristics of unmanned aviation development in *** operational characteristics and associated challenges due to diverse low-altitude users are analyzed,including operation concepts,UAS traffic management,technological test and verification,and *** light on the practices in Europe and the United States,this paper summarizes China's practices and progress in low-altitude operations management,and analyzes future technological development needs and trends,as well as feasible implementation pathways and measures based on actual needs.

关键词： UAS Low-altitude airspace UAS traffic management Exploration and practice