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Advances in Manufacturing 2024年第3期12卷 409-427页

作者： Zhong-Jie Yue Qiu-Ren Chen zu-guo bao Li Huang guo-Bi Tan Ze-Hong Hou Mu-Shi Li Shi-Yao Huang Hai-Long Zhao Jing-Yu Kong Jia Wang Qing Liu Key Laboratory for Light-weight Materials Nanjing Tech UniversityNanjing210009People’s Republic of China School of Advanced Technology Xi’an Jiaotong-Liverpool UniversitySuzhou215123JiangsuPeople’s Republic of China Material Academy JITRISuzhou215100JiangsuPeople’s Republic of China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240People’s Republic of China

This research presents an innovative approach to accurately predict the nugget diameter in resistance spot welding(RSW)by leveraging machine learning and transfer learning ***,low-fidelity(LF)data were obtained through finite element numerical simulation and design of experiments(DOEs)to train the LF machine learning ***,high-fidelity(HF)data were collected from RSW process experiments and used to fine-tune the LF model by transfer learning *** accuracy and generalization performance of the models were thoroughly *** results demonstrated that combining different fidelity datasets and employing transfer learning could significantly improve the prediction accuracy while minimize the costs associated with experimental trials,and provide an effective and valuable method for predicting critical process parameters in RSW.

关键词： Resistance spot welding(RSW) Nugget diameter prediction Multi-fidelity neural networks Transfer learning

Cosmological interpretation for the stochastic signal in pulsar timing arrays

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 43-50页

作者： Yu-Mei Wu zu-Cheng Chen Qing-guo Huang School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Astronomy Beijing Normal UniversityBeijing 100875China Advanced Institute of Natural Sciences Beijing Normal UniversityZhuhai 519087China Department of Physics and Synergistic Innovation Center for Quantum Effects and Applications Hunan Normal UniversityChangsha 410081China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China

The pulsar timing array(PTA)collaborations have recently reported compelling evidence for a stochastic signal consistent with a gravitational-wave *** this paper,we combine the latest data sets from NANOGrav,PPTA,and EPTA to explore cosmological interpretations for the PTA signal from first-order phase transitions,domain walls,and cosmic strings,*** find that the domain wall model is strongly disfavored with the Bayes factors compared with the first-order phase transitions and cosmic strings being 1/90 and 1/189,respectively,breaking the degeneracy among these models in individual data *** also find that:(1)a strong phase transition at temperatures below the electroweak scale is favored,and the bubble collisions make the dominant contribution to the energy density spectrum;(2)a small reconnection probability p<1.55×10^(-1)allowed by strings in(super)string theory is favored at the 95%confidence level,and ground-based detectors can further constrain the parameter space.

关键词： puslar timing arrays gravitational-wave background first-order phase transitions domain walls cosmic strings

Dinitrophenyl-oxadiazole compounds:Design strategy,synthesis,and properties of a series of new melt-cast explosives

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Defence Technology（防务技术） 2024年第5期35卷 100-107页

作者： bao-long Kuang Ting-wei Wang Cong Li Mou Sun Qamar-un-Nisa Tariq Chao Zhang Zhi-ming Xie zu-jia Lu Jian-guo Zhang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China China Wuzhou Engineering Group CO. LTD.Beijing 100053China

Melt-cast explosives are the most widely used energetic materials in military composite explosives,researchers have been unremittingly exploring high-energy and insensitive melt-cast *** this work,a series of dinitrophenyl-oxadiazole compounds were designed and *** compounds have an ideal low melting point(80-97℃),good detonation performance(detonation velocity D=6455-6971 m/s,detonation pressure P=18-19 GPa)and extreme insensitive nature(impact sensitivity≥60 J,friction sensitivity>360 N).All these compounds were well characterized by nuclear magnetic resonance,fourier transform infrared spectroscopy,elemental *** 2,3 were unambiguously confirmed by X-ray single crystal diffraction *** a result,their overall properties are superior to traditional melt-cast explosives trinitrotoluene(TNT)and dinitroanisole(DNAN)which may have excellent potential applications in insensitive melt-cast explosives.

关键词： Dinitrophenyl-oxadiazole Melt-cast explosive Low sensitivity

Fullerenes and derivatives as electrocatalysts: Promises and challenges

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Green Energy & Environment 2024年第1期9卷 7-27页

作者： Kun guo Ning Li Lipiao bao Xing Lu State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

Carbon-based metal-free nanomaterials are promising alternatives to precious metals as electrocatalysts of key energy storage and conversion *** paramount signiﬁcance are the establishment of design principles by understanding the catalytic mechanisms and identifying the active *** from sp2-conjugated graphene and carbon nanotube,fullerene possesses unique characteristics that are growingly being discovered and exploited by the electrocatalysis *** instance,the well-deﬁned atomic and molecular structures,the good electron afﬁnity to tune the electronic structures of other substances,the intermolecular self-assembly into superlattices,and the on-demand chemical modiﬁcation have endowed fullerene with incomparable advantages as electrocatalysts that are otherwise not applicable to other carbon *** increasing studies are being reported on this intriguing topic,it is necessary to provide a state-of-the-art overview of the recent *** review takes such an initiative by summarizing the promises and challenges in the electrocatalytic applications of fullerene and its *** content is structured according to the composition and structure of fullerene,including intact fullerene(e.g.,fullerene composite and superlattices)and fullerene derivatives(e.g.,doped,endohedral,and disintegrated fullerene).The synthesis,characterization,catalytic mechanisms,and deﬁciencies of these fullerene-based materials are explicitly *** conclude it by sharing our perspectives on the key aspects that future efforts shall consider.

关键词： Fullerene Fullerene derivative Metal-free catalyst Structural defect Electrocatalyst

Microplastics in sediment of the Three Gorges Reservoir:abundance and characteristics under different environmental conditions

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Journal of Oceanology and Limnology 2024年第1期42卷 101-112页

作者： Wang LI Bo zu Yiwei LIU Juncheng guo Jiawen LI College of River and Ocean Engineering Chongqing Jiaotong UniversityChongqing 400074China Chongqing Research Academy of Ecology and Environmental Sciences Chongqing 401147China

Freshwater microplastic pollution is an urgent issue of global concern,and research on the distribution in reservoirs is *** investigated the microplastic pollution levels in wet sediments collected from the Three Gorges Reservoir,the largest reservoir of *** show that microplastics were ubiquitous in the sediments of the Three Gorges Reservoir,and their abundance ranged from 59 to 276 pp/kg(plastic particles per kg,dry weight).Economic development and total population were important factors affecting the spatial heterogeneity of microplastic abundance,and the contribution of large cities along the reservoir to microplastic pollution should be paid with more *** microplastics were the most abundant type of microplastic particles in reservoir sediments,whereas polystyrene,polypropylene,and polyamide were the main types of *** apparent spatial heterogeneity in morphology and color of microplastics is attributed to different anthropogenic or landbased pollution ***,the accumulation of microplastics near the inlet of tributaries reflects the role of potential contributors of *** importantly,multiple bisphenols(BPs)and heavy metals detected at the microplastic surfaces indicate that microplastics can act as carriers of these pollutants in the environment in the same way as sediments did,which may alter the environmental fate and toxicity of these ***,we conclude that the Three Gorges Reservoir had been contaminated with microplastics,which posed a stress risk for organisms who ingest them along with their associated pollutants(BPs,heavy metals).

关键词： microplastics Three Gorges Reservoir sediment bisphenol heavy metal

Status and trends of carbon emissions research at the county level in China

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Advances in Climate Change Research 2024年第2期15卷 338-352页

作者： Ang-zu CAI Ru guo Yu-Hao ZHANG Jiang WU College of Environmental Science and Engineering Institute of Environmental Planning and ManagementTongji UniversityShanghai 200092China Institute of Carbon Neutrality Tongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China College of Architecture and Urban Planning Tongji UniversityShanghai 200092China Megacity Elaborated Urban Governance Institute Tongji UniversityShanghai 200092China

This study provides a comprehensive overview of the challenges to achieving carbon neutrality at the county level in China and offers targeted recommendations,laying the groundwork for future specialized research in this area.A total of 283 relevant studies(2004-2023)were analyzed to assess county-level carbon emissions through three phases:bibliometric analysis,frontier analysis,and future *** findings reveal that publication trends were largely influenced by domestic and foreign *** cluster discerns ten primary themes,ranging from conceptual frameworks to research *** frontier analysis of the literature highlights the leading research areas,which include carbon neutrality pathway,driving factors,spatiotemporal variation of carbon emissions,the co-effects of pollutants and carbon reduction,and carbon emissions in China's rural *** from the results of bibliometric and frontier analyses,this study elucidates the recommendations for achieving carbon neutrality at the county level from three perspectives:effective regional policy guidance,emphasis on ecological conservation,and the deployment of advanced carbon reduction and sequestration *** study enriches the body of knowledge on carbon emissions at the county level and holds significant implications for China's comprehensive push towards achieving its carbon neutrality objectives.

关键词： Carbon emissions Emission reduction County Carbon neutrality Sustainability

Fast and Adaptive Multi-Agent Planning under Collaborative Temporal Logic Tasks via Poset Products

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Research 2024年第2期2024卷 81-94页

作者： Zesen Liu Meng guo Weimin bao Zhongkui Li Deparment of Mechanics and Engineering Science College of EngineeringPeking UniversityBejing 0081 China Science and Technology Commission of China Aerospace Science and Technology Corporation Beijing 100048China

Efficient coordination and planning is essential for large-scale multi-agent systems that collaborate in a shared dynamic environment. Heuristic search methods or learning-based approaches often lack the guarantee on correctness and performance. Moreover, when the collaborative tasks contain both spatial and temporal requirements, e.g., as linear temporal logic (LTL) formulas, formal methods provide a verifiable framework for task planning. However, since the planning complexity grows exponentially with the number of agents and the length of the task formula, existing studies are mostly limited to small artificial cases. To address this issue, a new planning paradigm is proposed in this work for system-wide temporal task formulas that are released online and continually. It avoids two common bottlenecks in the traditional methods, i.e., (a) the direct translation of the complete task formula to the associated B點hi automaton and (b) the synchronized product between the B點hi automaton and the transition models of all agents. Instead, an adaptive planning algorithm is proposed, which computes the product of relaxed partially ordered sets (R-posets) on-the-fly and assigns these subtasks to the agents subject to the ordering constraints. It is shown that the first valid plan can be derived with a polynomial time and memory complexity with respect to the system size and the formula length. Our method can take into account task formulas with a length of more than 400 and a fleet with more than 400 agents, while most existing methods fail at the formula length of 25 within a reasonable duration. The proposed method is validated on large fleets of service robots in both simulation and hardware experiments.

关键词： hardware service system

Seasonal variation of mesoscale eddy intensity in the global ocean

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Acta Oceanologica Sinica 2024年第1期43卷 48-58页

作者： Yongcan zu Yue Fang Shuangwen Sun Libao Gao Yang Yang Guijun guo First Institute of Oceanography/Key Laboratory of Marine Science and Numerical Modeling Ministry of Natural ResourcesQingdao 266061China Laboratory for Regional Oceanography and Numerical Modeling Laoshan LaboratoryQingdao 266237China Shandong Key Laboratory of Marine Science and Numerical Modeling Qingdao 266061China

Mesoscale eddies are a prominent oceanic phenomenon that plays an important role in oceanic mass transport and energy *** by rotational speed,the eddy intensity is one of the most fundamental properties of an ***,the seasonal spatiotemporal variation in eddy intensity has not been examined from a global ocean *** this study,we unveil the seasonal spatiotemporal characteristics of eddy intensity in the global ocean by using the latest satellite-altimetry-derived eddy trajectory data *** results suggest that the eddy intensity has a distinct seasonal variation,reaching a peak in spring while attaining a minimum in autumn in the Northern Hemisphere and the opposite in the Southern *** seasonal variation of eddy intensity is more intense in the tropical-subtropical transition zones within latitudinal bands between 15°and 30°in the western Pacific Ocean,the northwestern Atlantic Ocean,and the eastern Indian Ocean because baroclinic instability in these areas changes *** analysis found that the seasonal variation of baroclinic instability precedes the eddy intensity by a phase of 2–3 months due to the initial perturbations needing time to grow into mesoscale eddies.

关键词： seasonal variation mesoscale eddy intensity baroclinic instability global ocean

New process for treating boron-bearing iron ore by flash reduction coupled with magnetic separation

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 473-484页

作者： Qipeng bao Lei guo Hong Yong Sohn Haibin zuo Feng Liu Yongliang Gao Zhancheng guo State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Department of Materials Science&Engineering University of UtahUtah 84112USA China ENFI Engineering Corporation Beijing 100038China

Boron is an important industrial raw material often sourced from minerals containing different compounds that cocrystallize,which makes it difficult to separate the mineral phases through conventional *** study proposed a new treatment called flash reduction-melting separation(FRMS)for boron-bearing iron *** this method,the concentrates were first flash-reduced at the temperature under which the particles melt,and the slag and the reduced iron phases disengaged at the particle *** reduc-tion and melting effects were achieved above 1550℃.The B_(2)O_(3) content in the separated slag was over 18wt%,and the B content in the iron was less than 0.03wt%.The proposed FRMS method was tested to investigate the effects of factors such as ore particle size and tem-perature on the reduction and melting steps with and without pre-reducing the raw *** mineral phase transformation and morphology evolution in the ore particles during FRMS were also comprehensively analyzed.

关键词： ludwigite boron-bearing iron concentrate flash reduction melting separation boron

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玉米和胡萝卜的体胚发生与蛋白质表达

安徽农业科学 2010年第19期38卷 9979-9980页

作者：郭祖宝潍坊学院生物工程学院山东潍坊261061

[目的]研究玉米和胡萝卜体胚发生中的生理生化变化,从而为调控其体胚发生过程提供依据。[方法]研究单子叶植物代表玉米和双子叶植物代表胡萝卜体胚发生的适合培养基,并利用电泳技术对其体胚发生过程中的可溶性蛋白进行比较。[结果]培养... 详细信息

[目的]研究玉米和胡萝卜体胚发生中的生理生化变化,从而为调控其体胚发生过程提供依据。[方法]研究单子叶植物代表玉米和双子叶植物代表胡萝卜体胚发生的适合培养基,并利用电泳技术对其体胚发生过程中的可溶性蛋白进行比较。[结果]培养基MS+6-BA1.0mg/L+2,4-D0.2mg/L+CH500mg/L较适于玉米愈伤组织的发生;培养基B5+2,4-D0.2mg/L+6-BA0.2mg/L较适于胡萝卜愈伤组织的发生。玉米愈伤组织中存在活跃的蛋白表达;而胡萝卜愈伤组织中的蛋白表达水平则比下胚轴对照明显下降。二者蛋白质表达的差异可能与物种差异有关。[结论]发现了单子叶植物和双子叶植物体胚发生中蛋白质表达的规律。

关键词：玉米胡萝卜体胚发生蛋白质表达