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Reliable calculations of nuclear binding energies by the Gaussian process of machine learning

Nuclear science and Techniques 2024年第6期35卷 130-144页

作者： Zi-Yi Yuan Dong Bai Zhen Wang Zhong-Zhou ren school of Physics science and Engineering Tongji UniversityShanghai 200092China College of science Hohai UniversityNanjing 211100China Key Laboratory of Advanced Micro-structure Materials Ministry of EducationShanghai 200092China

Reliable calculations of nuclear binding energies are crucial for advancing the research of nuclear physics.Machine learning provides an innovative approach to exploring complex physical problems.In this study,the nuclear binding energies are modeled directly using a machine-learning method called the Gaussian process.First,the binding energies for 2238 nuclei with Z>20 and N>20 are calculated using the Gaussian process in a physically motivated feature space,yielding an average deviation of 0.046 MeV and a standard deviation of 0.066 MeV.The results show the good learning ability of the Gaussian process in the studies of binding energies.Then,the predictive power of the Gaussian process is studied by calculating the binding energies for 108 nuclei newly included in AME2020.The theoretical results are in good agreement with the experimental data,reflecting the good predictive power of the Gaussian process.Moreover,the-decay energies for 1169 nuclei with 50≤Z≤110 are derived from the theoretical binding energies calculated using the Gaussian process.The average deviation and the standard deviation are,respectively,0.047 MeV and 0.070 MeV.Noticeably,the calculated-decay energies for the two new isotopes 204 Ac(Huang et al.Phys Lett B 834,137484(2022))and 207 Th(Yang et al.Phys Rev C 105,L051302(2022))agree well with the latest experimental data.These results demonstrate that the Gaussian pro-cess is reliable for the calculations of nuclear binding energies.Finally,the-decay properties of some unknown actinide nuclei are predicted using the Gaussian process.The predicted results can be useful guides for future research on binding energies and-decay properties.

关键词： Nuclear binding energies decay Machine learning Gaussian process

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Prescribed time control based on the periodic delayed sliding mode surface without singularities

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science China(Information sciences) 2024年第7期67卷 256-270页

作者： Bin ZHOU Yi DING Kang-Kang ZHANG Guang-ren DUAN Center for Control Theory and Guidance Technology Harbin Institute of Technology

In this paper, nonsingular prescribed-time control is studied based on periodic delayed sliding mode surfaces. Different from the existing sliding mode control, where either singularity problems may appear or the convergence time depends on the initial state, the proposed sliding mode control approaches can achieve prescribed-time convergence without singularity. The proposed nonsingular sliding mode control approaches can be applied to both second-order and high-order nonlinear systems with prescribed-time convergence. As applications of the proposed sliding mode control approaches, the control of hypersonic vehicle systems is revisited. Numerical simulations on the nonlinear model of the hypersonic vehicle system show the effectiveness of the proposed methods.

关键词： prescribed-time control smooth periodic delayed feedback sliding mode control high-order nonlinear systems hypersonic vehicle systems

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The impact of demographic dynamics on food consumption and its environmental outcomes:Evidence from China

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Journal of Integrative Agriculture 2024年第2期23卷 414-429页

作者： shaoting Li Xuan Chen Yanjun ren Thomas Glauben College of Economics and Management Northwest A&F UniversityYangling 712100China Leibniz Institute of Agricultural Development in Transition Economies(IAMO) Halle(Saale)06120Germany sino-German Center for Agricultural and Food Economics Northwest A&F UniversityYangling 712100China

With increasing population and changing demographics,food consumption has experienced a significant transition in quantity and quality.However,a dearth of knowledge remains regarding its environmental impacts and how it responds to demographic dynamics,particularly in emerging economies like China.Using the two-stage Quadratic Almost Demand system(QUAIDs)model,this study empirically examines the impact of demographic dynamics on food consumption and its environmental outcomes based on the provincial data from 2000 to 2020 in China.Under various scenarios,according to changes in demographics,we extend our analysis to project the long-term trend of food consumption and its environmental impacts,including greenhouse gas(GHG)emissions,water footprint(WF),and land appropriation(LA).The results reveal that an increase in the proportion of senior people significantly decreases the consumption of grain and livestock meat and increases the consumption of poultry,egg,and aquatic products,particularly for urban residents.Moreover,an increase in the proportion of males in the population leads to higher consumption of poultry and aquatic products.Correspondingly,in the current scenario of an increased aging population and sex ratio,it is anticipated that GHG emissions,WF,and LA are likely to decrease by 1.37,2.52,and 3.56%,respectively.More importantly,in the scenario adhering to the standards of nutritional intake according to the Dietary Guidelines for Chinese Residents in 2022,GHG emissions,WF,and LA in urban areas would increase by 12.78,20.94,and 18.32%,respectively.Our findings suggest that changing demographics should be considered when designing policies to mitigate the diet-environment-health trilemma and achieve sustainable food consumption.

关键词： demographic dynamics food consumption environmental impacts nutrition intakes

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A model reduction approach for discrete-time linear time-variant systems with delayed inputs

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science China(Information sciences) 2024年第4期67卷 197-217页

作者： Ai-Guo WU Guang-ren DUAN Yu WANG Jie ZHANG school of Mechanical Engineering and Automation Harbin Institute of Technology(Shenzhen) HIT Wuhu Robot Technology Research Institute Center for Control science and Technology Southern University of Science and Technology

A model reduction approach is presented for discrete-time linear time-variant input-delayed systems. According to this proposed approach, a dynamical variable is constructed by taking advantage of the current state and historical information of input. It is revealed that the behavior of this dynamical variable is governed by a discrete-time linear delay-free system. It is worth noting that the presented variable transformation does not require the system matrix to be invertible. Based on the reduced delay-free models,stabilizing control laws can be easily obtained for the original delayed system. For the case with a single input delay, the constructed variable is an exact prediction for the future state, and thus the stabilizing control law could be designed by replacing the future state with its prediction. Finally, three discrete-time periodic systems with delayed input are employed to illustrate how to utilize the presented model reduction approaches.

关键词： reduction approach predictor-based feedback time-varying systems delayed input periodic system

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A convenient method for measuring gas-liquid volumetric mass transfer coefficient in micro reactors

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Chinese Chemical Letters 2024年第4期35卷 389-392页

作者： Haoyang Wang Ronghao Zhang Yanlun ren Li Zhang school of Mechanical and Power Engineering East China University of Science and TechnologyShanghai 200237China

The research on gas-liquid multiphase reactions using micro reactors is becoming increasingly widespread, given their excellent mass transfer performance. Establishing an accurate and reliable method to measure the gas-liquid mass transfer performance of micro reactors is crucial for evaluating and optimizing the design of micro reactor structure. In this paper, the physical absorption method of aqueous solution-CO_(2) and the chemical absorption method of sodium carbonate solution-CO_(2) were proposed. By analyzing the chemical reaction equilibrium during the absorption process, the relationship between the mass transfer of CO_(2) and the solubility of hydroxide ions in the solution was established, and the total gas-liquid mass transfer coefficient was immediately obtained by measuring the p H value. The corresponding testing platform and process have been established based on the characteristics of the proposed method to ensure fast and accurate measurement. In addition, the chemical absorption method takes into account temperature factors that were not previously considered. The volumetric mass transfer coefficient measured by these two methods is in the same range as those measured by other methods using the same microchannel structure in previous literature. The methods have the advantages of low equipment cost, faster measurement speed, and simpler procedures, which can facilitate its wide application to the evaluation of the mass transfer performance and hence can guide the structure optimization of microchannel reactors.

关键词： Volumetric mass transfer coefficient measurement Gas-liquid two phase Micro reactors Physical absorption Chemical absorption

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Reinforcement Learning-Based Dynamic Order Recommendation for On-Demand Food Delivery

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Tsinghua science and Technology 2024年第2期29卷 356-367页

作者： Xing Wang Ling Wang Chenxin Dong Hao ren Ke Xing Department of Automation Tsinghua UniversityBeijing 100080China school of Mechanical and Automotive Engineering Qingdao Hengxing University of Science and TechnologyQingdao 266100China Meituan Beijing 100015China

On-demand food delivery(OFD)is gaining more and more popularity in modern society.As a kernel order assignment manner in OFD scenario,order recommendation directly influences the delivery efficiency of the platform and the delivery experience of riders.This paper addresses the dynamism of the order recommendation problem and proposes a reinforcement learning solution method.An actor-critic network based on long short term memory(LsTM)unit is designed to deal with the order-grabbing conflict between different riders.Besides,three rider sequencing rules are accordingly proposed to match different time steps of the LsTM unit with different riders.To test the performance of the proposed method,extensive experiments are conducted based on real data from Meituan delivery platform.The results demonstrate that the proposed reinforcement learning based order recommendation method can significantly increase the number of grabbed orders and reduce the number of order-grabbing conflicts,resulting in better delivery efficiency and experience for the platform and riders.

关键词： on-demand food delivery order recommendation reinforcement learning actor-critic network long short term memory

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Parameter-Free shifted Laplacian Reconstruction for Multiple Kernel Clustering

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IEEE/CAA Journal of Automatica sinica 2024年第4期11卷 1072-1074页

作者： Xi Wu Zhenwen ren F.Richard Yu the school of National Defence science and Technology Southwest University of Science and TechnologyMianyang 621010China the school of National Defence science and Technology Southwest University of Science and TechnologyMianyang 621010 the Guangxi Key Laboratory of Machine Vision and Intelligent Control Wuzhou UniversityWuzhou 543002 the Guangdong Laboratory of Artificial Intelligence and Digital Economy(sZ) Shenzhen 518060China

Dear Editor,This letter proposes a parameter-free multiple kernel clustering(MKC)method by using shifted Laplacian reconstruction.Traditional MKC can effectively cluster nonlinear data,but it faces two main challenges:1)As an unsupervised method,it is up against parameter problems which makes the parameters intractable to tune and is unfeasible in real-life applications;2)Only considers the clustering information,but ignores the interference of noise within Laplacian.

关键词： parameter letter Parameter

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Cavity-enhanced photoacoustic dual-comb spectroscopy

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Light(science & Applications) 2024年第4期13卷 610-618页

作者： Zhen Wang Qinxue Nie Haojia sun Qiang Wang simone Borri Paolo De Natale Wei ren Department of Mechanical and Automation Engineering The Chinese University of Hong KongNew TerritoriesHong Kong SARChina. state Key Laboratory of Applied Optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of Sciences130033 ChangchunChina. CNRINO-Istituto Nazionale di Ottica and LENS-European Laboratory for Nonlinear Spectroscopy50019 Sesto FiorentinoItaly

Photoacoustic dual-comb spectroscopy(DCs),converting spectral information in the optical frequency domain to the audio frequency domain via multi-heterodyne beating,enables background-free spectral measurements with high resolution and broad bandwidth.However,the detection sensitivity remains limited due to the low power of individual comb lines and the lack of broadband acoustic resonators.Here,we develop cavity-enhanced photoacoustic DCs,which overcomes these limitations by using a high-finesse optical cavity for the power amplification of dual-frequency combs and a broadband acoustic resonator with a flat-top frequency response.We demonstrate high-resolution spectroscopic measurements of trace amounts of C2H2,NH3 and CO in the entire telecommunications C-band.The method shows a minimum detection limit of 0.6 ppb C2H2 at the measurement time of 100 s,corresponding to the noise equivalent absorption coefficient of 7×10−10 cm−1.The proposed cavityenhanced photoacoustic DCs may open new avenues for ultrasensitive,high-resolution,and multi-species gas detection with widespread applications.

关键词： individual cavity spectroscopy

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Investigating the elliptic anisotropy of identified particles in p-Pb collisions with a multi-phase transport model

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Nuclear science and Techniques 2024年第2期35卷 160-169页

作者： si-Yu Tang Liang Zheng Xiao-Ming Zhang ren-Zhuo Wan school of Mathematical and Physical sciences Wuhan Textile UniversityWuhan 430200China school of Mathematics and Physics China University of Geosciences(Wuhan)Wuhan 430074China Key Laboratory of Quark and Lepton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan 430079China Hubei Key Laboratory of Digital Textile Equipment Wuhan Textile UniversityWuhan 430200China school of Electronic and Electrical Engineering Wuhan Textile UniversityWuhan 430200China

The elliptic azimuthal anisotropy coefficient(v_(2))of the identified particles at midrapidity(|η|<0.8)was investigated in p-Pb collisions at√s_(NN)=5.02 TeV using a multi-phase transport model(AMPT).The calculatio... 详细信息

The elliptic azimuthal anisotropy coefficient(v_(2))of the identified particles at midrapidity(|η|s investigated in p-Pb collisions at√s_(NN)=5.02 TeV using a multi-phase transport model(AMPT).The calculations of differential v_(2)based on the advanced flow extraction method of light flavor hadrons(pions,kaons,protons,andΛ)in small collision systems were extended to a wider transverse momentum(p_(T))range of up to 8 GeV/c for the first time.The string-melting version of the AMPT model provides a good description of the measured p_(T)-differential v_(2)of the mesons but exhibits a slight deviation from the baryon v_(2).In addition,we observed the features of mass ordering at low p_(T)and the approximate number-of-constituentquark(NCQ)scaling at intermediate p_(T).Moreover,we demonstrate that hadronic rescattering does not have a significant impact on v_(2)in p-Pb collisions for different centrality selections,whereas partonic scattering dominates in generating the elliptic anisotropy of the final particles.This study provides further insight into the origin of collective-like behavior in small collision systems and has referential value for future measurements of azimuthal anisotropy.

关键词： Azimuthal anisotropy small collision systems Transport model

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Effects of acid mine drainage on photochemical and biological degradation of dissolved organic matter in karst river water

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Journal of Environmental sciences 2024年第1期135卷 26-38页

作者： Linwei Li Xingxing Cao Chujie Bu Pan Wu Biao Tian Yongheng Dai Yeye ren College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Karst Georesources and Environment Ministry of EducationGuizhou UniversityGuiyang 550025China Guizhou Karst Environmental Ecosystems Observation and Research station Ministry of EducationGuizhou UniversityGuiyang 550025China

Dissolved organic matter(DOM)can be removed or transformed by photochemical and biological processes,producing the negative effect of transforming organic carbon into inorganic carbon,which plays a vital role in the karst carbon cycle.However,acid mine drainage(AMD)will affect this process,so the degradation of DOM in karst river water(KRW)needs to be studied in this context.In this study,to reveal the evolution processes of DOM under photochemical and biological conditions in AMD-impacted KRW,AMD and KRW were mixed in different ratios under conditions of visible light irradiation(VL),biodegradation(BD),ultraviolet irradiation(UV)and ultraviolet irradiation+biodegradation(UV+BD).The average DOC concentrations in samples after mixing AMD and KRW in different proportions decreased significantly(by 23%)in UV+BD,which was 1.2–1.4 times higher than under the other conditions and would lead to a significant release of inorganic carbon.Further analysis of the fluorescence parameters via parallel factor analysis(PARAFAC)revealed that the DOM fluorescence components in AMD comprised mainly protein-like substances derived from autochthonous components,while the DOM fluorescence components in KRW were mainly humic-like substances with both autochthonous and allochthonous sources.Therefore,AMD could promote both the photochemical and biological degradation of DOM in karst receiving streams,resulting in the conversion of DOC to inorganic carbon.The results showed that the synergistic effects of UV+BD and AMD accelerated the degradation of DOM and the release of inorganic carbon in KRW,thus affecting the stability of the karst carbon cycle.

关键词： Acid mine drainage Dissolved organic matter Karst river water Photochemical degradation Biological degradation

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