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Journal of Mountain Science 2021年第2期18卷 307-322页

作者： YANG Wei-lin HAN Ye-song PENG Xu RAN Ze-ze liu Qing liu geng-nian College of Urban and Environmental Sciences Peking UniversityBeijing 100871China

Owing to the remoteness of the Longriba area and the lack of dating records,it is extremely challenging to reconstruct the chronology and extent of the paleoglaciers in this *** this paper,we combined limited observational data with automated modelling for paleoglacial *** first identified a broadly distributed paleoglacier from satellite imagery and field investigation based on the sediment-landform assemblage principle and dated it to 23.1±1.4~19.5±1.2 ka by ^(10)Be exposure dating,corresponding to the global Last Glacial Maximum(gLGM).Then,we reconstructed the extent and ice surface of 171 paleoglaciers formed during the similar period based on geomorphological evidence and‘ice surface profile’*** results showed that the paleoglacial coverage was 426.5 km2,with an ice volume of 38.1 km^(3),in the Longriba *** reconstructed equilibrium line altitudes(ELAs)based on modelled ice surfaces yielded an average of 4245±66 m above sea level(asl),~725±73 m lower than the present ELA(4970±29 m asl).The temperature was~5.51-6.68℃lower,and the precipitation was~30-34%less in Longriba,during the gLGM compared to the present *** glacial advance was mainly driven by colder climate that was synchronous with Northern Hemisphere cooling events.

关键词： Ice surface profile ^(10)Be surface exposure dating Paleoglacial reconstruction Paleoclimate reconstruction Global Last Glacial Maximum Eastern Tibetan Plateau

The property, age and formation environment of the palaeokarst in Qinghai-Xizang Plateau

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Journal of Geographical Sciences 2002年第2期12卷 21-29页

作者： Gao Quan-zhou Cui Zhi-jiu Tao Zhen liu geng-nian Hong Yun Department of Geography Zhongshan University Guangzhou 510275 Department of Geography Peking University 北京 100871 State Environmental Protection Administration 北京 100035

The karst landforms distributed on the Qinghai-Xizang (Tibet) Plateau can be genetically classed with the Tertiary underground karst, which were gradually exhumed to the surface with the uplift of the plateau during Quaternary period. The relative deposits of the Tertiary palaeokarst processes, such as the residuum and speleothem, were discovered recently in the southern and southeastern fringe areas of the plateau, where has geological-currently been disintegrated by the headward erosion processes of the modern river systems. The major chemical components of the clay portion of the residuum consist mainly of SiO2, Al2O3 and Fe2O3. The clay minerals composition of the clay portion belongs to illite-kaolinite pattern for most of the residuum samples, and kaolinite-illite pattern for a few of the samples. It can be judged from the silicic acid index and the clay minerals composition that the formation of the residuum of the Plateau was in its initial phase. However, such a lower chemical weathering index only reflected the weathering degree in the bottom or lower parts of the lateritic weathering crust. The relatively intensive chemical weathering processes of the surface layers of the lateritic weathering crust could be logically speculated. The surface feature textures of quartz grains in the residuum were formed mainly by the chemical erosion, which revealed a long-term humid-tropical environment when the residuum and the palaeokarst formed.

关键词： palaeokarst lateritic residuum chemical weathering Tertiary Period planation surface Qinghai-Xizang Plateau

High-performance nickel metal hydride battery anode with enhanced durability and excellent low-temperature discharge capability

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Nano Research 2024年第10期17卷 8819-8825页

作者： Zhitao Chen Huitian liu Jean Nei nian liu School of Chemical and Biomolecular Engineering Georgia Institute of TechnologyAtlantaGA 30332USA GP Batteries HongkongChina

Current AB_(5)-type hydrogen storage alloys employed in nickel-metal hydride(NiMH)batteries exhibit exceptional low-temperature discharge performance but suffer from limited cycle life and insufficient high-temperature *** overcome these challenges,we introduce a hydrothermal synthesized LaF_(3)coating layer on the surface of the AB_(5)anode *** LaF_(3)coating layer adds a protective barrier for the active material,significantly improving the battery's cycle life and high-temperature *** findings indicate that(1)the LaF_(3)coated anode demonstrates an extended cycle life with increased specific capacity and a capacity retention of 88%after 40 cycles of abusive overcharging and rapid discharging at room temperature.(2)The synthesized anode exhibits a 97%recovery of its specific capacity of 292.7 mAh/g following 144 h of high-temperature storage.(3)The low-temperature discharge capacity of the synthesized anode remains on par with the pristine AB_(5)alloy at 230.4 mAh/g in a-40℃*** research presents a significant advancement in hydrogen storage alloy coatings and offers valuable insights for designing electrodes in NiMH batteries.

关键词： nickel metal hydride(NiMH)batteries hydrothermal synthesis lanthanum fluoride discharge capacity low temperature

Synthesis and modification of nanowires anchored on electrodes for electrochemical and electrophysical applications

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Nano Research 2024年第10期17卷 8863-8884页

作者： Feiyang Mo Zhitao Chen nian liu Xing Xie School of Civil and Environmental Engineering Georgia Institute of Technology311 Ferst Drive NWAtlantaGA 30332USA School of Chemical and Biomolecular Engineering Georgia Institute of Technology311 Ferst Drive NWAtlantaGA 30332USA

The integration of nanowires onto electrode surfaces marks a significant advancement over traditional electrode materials,conferring upon nanowire-modified electrodes a vast array of applications within electrochemical and electrophysical *** nanowires used for electrode modification can be catalogized into two distinct types:anchored nanowires and free-standing nanowires.A critical advantage of anchored nanowires lies in their enhanced electrical connectivity with the substrate,which reduces electrode resistance and facilitates charge ***,the anchorage of nanowires onto electrodes provides additional mechanical support,bolstering the structural stability of the nanowire ***,we review the development of anchored nanowires designed for applications in energy storage,electrocatalysis,and electric field treatment(EFT)over the past *** focus on the synthesis and modification strategies employed for anchored nanowires,culminating in the evaluation of these fabrication and enhancement *** this analysis,we aim to furnish comprehensive insights into the preparation of anchored nanowires,guiding the selection of appropriate fabrication processes and subsequent functional modifications.

关键词： electrode modification direct growth etching energy storage electrocatalysis electric field treatment

AI for tribology:Present and future

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Friction 2024年第6期12卷 1060-1097页

作者： nian YIN Pufan YANG Songkai liu Shuaihang PAN Zhinan ZHANG State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical Engineering University of UtahSalt Lake CityUT 84112USA

With remarkable learning capabilities and swift operational speeds,artificial intelligence(AI)can assist researchers in swiftly extracting valuable patterns,trends,and associations from subjective *** behaviors are characterized by dependence on systems,evolution with time,and multidisciplinary *** friction process involves a variety of phenomena,including mechanics,thermology,electricity,optics,magnetics,and so ***,tribological information possesses the distinct characteristics of being multidisciplinary,multilevel,and multiscale,so that the application of AI in tribology is highly *** delineate the scope,classification,and recent trends of AI implementation in tribology,this review embarks on exploration of the tribology research *** comprehensively outlines the utilization of AI in basic theory of tribology,intelligent tribology,component tribology,extreme tribology,bio-tribology,green tribology,and other ***,considering the emergence of"tribo-informatics"as a novel interdisciplinary field,which combines tribology with informatics,this review elucidates the future directions and research framework of"AI for tribology".In this paper,tribo-system information is divided into 5 categories:input information(I),system intrinsic information(S),output information(O),tribological state information(Ts),and derived state information(Ds).Then,a fusion method among 5 types of tribo-system information and different AI technologies(regression,classification,clustering,and dimension reduction)has been proposed,which enables tribo-informatics methods to solve common problems such as tribological behavior state monitoring,behavior prediction,and system *** purpose of this review is to offer a systematic comprehension of tribo-informatics and to inspire new research ideas of ***,it aspires to enhance the efficiency of problem-solving in tribology.

关键词： artificial intelligence(AI) tribology machine learning tribo-informatics AI for tribology

AN EXPLANATION ON FOUR NEW DEFINITIONS OF FRACTIONAL OPERATORS

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Acta Mathematica Scientia 2024年第4期44卷 1271-1279页

作者： Jiangen liu Fazhan geng School of Mathematics and Statistics Changshu Institute of TechnologyChangshu 215500China Qin Institute of Mathematics Shanghai Hanjing Centre for Science and TechnologyShanghai 201609China

Fractional calculus has drawn more attentions of mathematicians and engineers in recent years.A lot of new fractional operators were used to handle various practical *** this article,we mainly study four new fractional operators,namely the CaputoFabrizio operator,the Atangana-Baleanu operator,the Sun-Hao-Zhang-Baleanu operator and the generalized Caputo type operator under the frame of the k-Prabhakar fractional integral ***,the theory of the k-Prabhakar fractional integral is regarded as a much broader than classical fractional ***,we firstly give a series expansion of the k-Prabhakar fractional integral by means of the k-Riemann-Liouville ***,a connection between the k-Prabhakar fractional integral and the four new fractional operators of the above mentioned was shown,*** terms of the above analysis,we can obtain this a basic fact that it only needs to consider the k-Prabhakar fractional integral to cover these results from the four new fractional operators.

关键词： k-Prabhakar fractional operator Caputo-Fabrizio operator Atangana-Baleanu operator Sun-Hao-Zhang-Baleanu operator generalized Caputo type operator

Prediction of bedload transport inside vegetation canopies with natural morphology

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Journal of Hydrodynamics 2024年第3期36卷 556-569页

作者： Li He Yu-qi Shan Chao liu Hui Cao Xing-nian liu Yakun Guo State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China Institute for Disaster Management and Reconstruction Sichuan UniversityChengdu610065China China Yangtze Power Co. Ltd.Yichang443002China Hubei Key Laboratory of Intelligent Yangtze and Hydroelectric Science Yichang443002China Faculty of Engineering and Informatics University of BradfordBradfordUK

Due to vegetation drag and vegetation-generated turbulence,bedload transport in vegetated channels is more complicated than that in nonvegetated *** is challenging to obtain accurate predictions of bedload transport in vegetated *** studies generally used rigid circular cylinders to simulate vegetation,and the impact of plant morphology on bedload transport was typically ignored;these methods deviate from natural scenarios,resulting in prediction errors in transport rates of more than an order of *** study measured bedload transport rates inside ***,*** and *** canopies and in arrays of rigid cylinders for *** impact of plant morphology on bedload transport in vegetated channels was *** the canopies of natural morphology,the primary factor driving bedload transport is the near-bed turbulent kinetic energy(TKE),which consists of both bed-generated and vegetation-generated turbulence.A method was proposed to predict the near-bed TKE inside canopies with natural *** the same solid volume fraction of plants,the transport rate inside canopies with a natural morphology is greater than or equal to that within an array of rigid cylinders,depending on the plant *** finding indicates that plant morphology has a significant impact on transport rates in vegetated regions and cannot be ignored,which is typical in *** classic bedload transport equations(the Meyer-Peter-Müller,Einstein,Engelund and Dou equations),which are suitable for bare channels(no vegetation),were modified in terms of the near-bed *** predicted near-bed TKE was inserted into these four equations to predict the transport rate in canopies with natural morphology.A comparison of the predictions indicated that the Meyer-Peter-Müller equation had the highest accuracy in predicting the transport rate in vegetated landscapes.

关键词： Vegetated landscapes turbulent kinetic energy(TKE) bedload transport plant morphology predictive methods

Efficient cache replacement framework based on access hotness for spacecraft processors

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中国空间科学技术（中英文） 2024年第2期44卷 74-88页

作者： GAO Xin nian Jiawei liu Hongjin YANG Mengfei Beijing Institute of Control Engineering Beijing 100190China Beijing SunWise Space Technology Co. Ltd.Beijing 100190China School of Computer Science and Technology Xidian UniversityXi'an 710071China China Academy of Space Technology Beijing 100094China

A notable portion of cachelines in real-world workloads exhibits inner non-uniform access ***,modern cache management rarely considers this fine-grained feature,which impacts the effective cache capacity of contemporary high-performance spacecraft *** harness these non-uniform access behaviors,an efficient cache replacement framework featuring an auxiliary cache specifically designed to retain evicted hot data was *** framework reconstructs the cache replacement policy,facilitating data migration between the main cache and the auxiliary *** traditional cacheline-granularity policies,the approach excels at identifying and evicting infrequently used data,thereby optimizing cache *** evaluation shows impressive performance improvement,especially on workloads with irregular access *** from fine granularity,the proposal achieves superior storage efficiency compared with commonly used cache management schemes,providing a potential optimization opportunity for modern resource-constrained processors,such as spacecraft ***,the framework complements existing modern cache replacement policies and can be seamlessly integrated with minimal modifications,enhancing their overall efficacy.

关键词： spacecraft processors cache management replacement policy storage efficiency memory hierarchy microarchitecture

Seismic-induced surficial failure of cohesive slopes using three-dimensional limit analysis:A case study of the Wangjiayan landslide in Beichuan, China

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 537-545页

作者： Gao Yufeng liu Yang geng Weijuan Zhang Fei Key Laboratory of the Ministry of Education for Geomechanics and Embankment Engineering College of Civil and Transportation EngineeringHohai UniversityNanjing 210098China Department of Civil Engineering Faculty of Civil Engineering and MechanicsJiangsu UniversityZhenjiang 212013China

A seismic-induced landslide is a common geological catastrophe that occurs in *** Wangjiayan landslide,which was triggered by the Wenchuan earthquake,is a typical case in *** Wanjiayan landslide caused many casualties and resulted in enormous property *** study constructs a simple surficial failure model based on the upper bound approach of three-dimensional(3D)limit analysis to evaluate the slope stability of the Wangjiayan case,while a traditional two-dimensional(2D)analysis is also conducted as a reference for comparison with the results of the 3D analysis.A quasi-static calculation is used to study the effect of the earthquake in terms of horizontal ground acceleration,while a parametric study is conducted to evaluate the critical cohesion of *** than employing a 3D analysis,using the 2D analysis yields an underestimation regarding the safety *** the Wangjiayan landslide,the difference in the factors of safety between the 3D and 2D analyses can reach 20%.The sliding surface morphology as determined by the 3D method is similar to actual morphology,and the parameters of both are also compared to analyze the reliability of the proposed 3D method.

关键词： landslide Wenchuan earthquake surficial failure limit analysis stability quasi-static

Microfluidic-oriented synthesis of enriched iridium nanodots/carbon architecture for robust electrocatalytic nitrogen fixation

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Green Energy & Environment 2024年第3期9卷 544-555页

作者： Hengyuan liu Xingjiang Wu Yuhao geng Xin Li Jianhong Xu The State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing100084China

Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless ***,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic ***,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon *** to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption *** a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH ***,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) *** microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.

关键词： Iridium nanodots Carbon Microfluidic technology Efficient synthesis Electrocatalytic nitrogen fixation