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Journal of Thermal Science 2024年第4期33卷 1509-1522页

作者： WANG Yuhao WANG Ruilin liu Lanhua XING Chenjian GUO Yafei YANG Qingshan YING Jiaheng SUN Jian LI Wenjia liu yuanyuan ZHAO Chuanwen School of Energy and Mechanical Engineering Nanjing Normal University China Huadian Group Co.LTD.Shanghai Branch Key Laboratory of Efficient Utilization of Low and Medium Grade Energy(Tianjin University) Ministry of Education of China Huadian Zhengzhou Mechanical Design Institute Company Limited

Coal-fired power plant is a major contributor to greenhouse gas emissions.The post-combustion capture is a promising method for CO2emission reduction but the high thermal demand is unbearable.To address this issue,solar thermal energy and CO2capture are jointly integrated into the coal-fired power plant in this study.The solar thermal energy is employed to meet the heat requirement of the CO2capture process,thereby avoiding the electricity loss caused by self-driven CO2capture.Furthermore,the heat released from the carbonation reaction of MgO adsorbent is integrated into the steam Rankine cycle.By partially substituting the extracted steam for feedwater heating,the electricity output of the power plant is further increased.According to the results from the developed model,the system could achieve a CO2capture rate of 86.5% and an electricity output enhancement of 9.8% compared to the reference system,which consists of a self-driven CO2capture coal-fired power plant and PV generation unit.The operational strategy is also optimized and the amount of CO2emission reduction on a typical day is increased by 11.06%.This work shows a way to combine fossil fuels and renewable energy for low carbon emissions and efficient power generation.

关键词： CO 2 capture parabolic trough collector solar aided coal-fired electricity generation

Synergic action of linear dispersion, second-order nonlinearity, and third-order nonlinearity in shaping the spectral profile of a femtosecond pulse transporting in a lithium niobate crystal

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Photonics Research 2024年第4期12卷 774-783页

作者： LIHONG HONG yuanyuan liu ZHI-YUAN LI State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

We present a detailed theoretical and numerical analysis on the temporal-spectral-spatial evolution of a highpeak-power femtosecond laser pulse in two sets of systems:a pure lithium niobate(LN)plate and a periodically poled lithium niobate(PPLN)plate.We develop a modified unidimensional pulse propagation model that considers all the prominent linear and nonlinear processes and carried out the simulation process based on an improved split-step Fourier transformation method.We theoretically analyze the synergic action of the linear dispersion effect,the second-order nonlinearity(2nd-NL)second-harmonic generation(SHG)effect,and the third-order nonlinearity(3rd-NL)self-phase modulation(SPM)effect,and clarify the physical mechanism underlying the peculiar and diverse spectral broadening patterns previously reported in LN and PPLN thin plate experiments.Such analysis and discussion provides a deeper insight into the synergetic contribution of these linear and nonlinear effects brought about by the interaction of a femtosecond laser pulse with the LN nonlinear crystal and helps to draw a picture to fully understand these fruitful optical physical processes,phenomena,and laws.

关键词： pulse nonlinearity lithium

Characteristics and sources of peroxyacetyl nitrate(PAN)in the rural North China Plain:Results from1-year continuous observations

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Journal of Environmental Sciences 2024年第4期138卷 719-731页

作者： Xin liu Xiaowei He Chenglong Zhang Yifei Song Shuyang Xie Chengtang liu Pengfei liu yuanyuan Zhang Yujing Mu Junfeng liu Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China

Peroxyacetyl nitrate(PAN)is an important photochemical pollutant in the troposphere,whereas long-term measurements are scarce in rural areas in North China Plain(NCP),resulting in unclear seasonal variations and sources of PAN in rural NCP.In this study,we conducted a 1-year observation of PAN during 2021-2022 at the rural NCP site.The average concentrations of PAN were 1.10,0.75,0.65,and 0.88 ppbv in spring,summer,autumn,and winter,respectively,with a 1-year average of 0.81±0.60 ppbv.Calculations indicate that the loss of PAN through thermal decomposition in summer accounts for 43.2% of the total formed PAN,which is an important reason for the low concentration of PAN in summer.We speculate that since the correlation between PAN and O_(3) in winter is significantly lower than that in other seasons,the observed regional transport of PAN cannot be ignored in winter.Through budget analysis,regional transport accounted for 12.8% and 55.9% of the observed PAN on the spring and winter pollution days,respectively,which showed that regional transport played key roles during the photochemical pollution of the rural NCP in winter.The potential source contribution function revealed that the transported PAN mainly comes from southern Hebei in spring.In winter,the transported PAN was mainly from Langfang,Hengshui,and southern Beijing.Our findings may aid in understanding PAN variations in different seasons in rural areas and highlight the impact of regional transport on the PAN budget.

关键词： Photochemical pollution Peroxyacetyl nitrate(PAN) Seasonal variations Regional transport Rural area

Particle size dependence of the microsegregation and microstructure in the atomized Ni-based superalloy powders:Theoretical and experimental study

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Journal of Materials Science & Technology 2024年第4期171卷 54-65页

作者： Jikang Li Mingsheng Yang Yunfei Cai yuanyuan Zhang Qingshuai Feng Jiantao liu Tong liu Key Laboratory of Aerospace Materials and Performance(Ministry of Education)School of Materials Science and Engineering Beihang UniversityBeijing 100191China Central Iron and Steel Research Institute Beijing 100081China

The microstructure and microsegregation of atomized powder,which depend on their sizes,are of great importance to the mechanical properties of the consolidated bulk materials.Therefore,it is necessary to reveal the relationship between particle size and powder attributes.The effects of particle size on the so-lidification characterization of the atomized Ni-based superalloy powders were studied via finite element simulation.Based on the simulations,a model was developed to predict the microsegregation and mi-crostructure of atomized powders with different sizes and study the influence of thermal history on the powder attributes during the atomization processes.The radiation heat transfer and temperature gradi-ent within the rapid solidification alloy powders were taken into account in this model.For validating the accuracy of the model,the predictions of the present model were compared with the microsegregation and microstructure of the specific size powder close to the screen mesh size.The results showed that mi-crostructure depended primarily on the temperature gradient within the powder,while the solidification rate had a more significant effect on the microsegregation.The model predicted microstructure features in agreement with the experiment,and for microsegregation,the deviations of prediction for most ele-ments were less than 10%.This work provides a new model to precisely predict the microsegregation and microstructure of the atomized alloy powders and sets a foundation to control the powder features for various engineering applications.

关键词： Particle size Solidification microstructure Microsegregation Numerical simulation

A novel interpretable multilevel wavelet decomposition deep network for actual heartbeat classification

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Science China Technological Sciences 2024年第6期67卷 1842-1854页

作者： JIN YanRui LI ZhiYuan TIAN yuanyuan WEI XiaoYang liu ChengLiang School of Mechanical Engineering Shanghai Jiao Tong University

Arrhythmias may lead to sudden cardiac death if not detected and treated in time. A supraventricular premature beat(SPB) and premature ventricular contraction(PVC) are important categories of arrhythmia disease. Recently, deep learning methods have been applied to the PVC/SPB heartbeats detection. However, most researchers have focused on time-domain information of the electrocardiogram and there has been a lack of exploration of the interpretability of the model. In this study, we design an interpretable and accurate PVC/SPB recognition algorithm, called the interpretable multilevel wavelet decomposition deep network(IMWDDN). Wavelet decomposition is introduced into the deep network and the squeeze and excitation(SE)-Residual block is designed for extracting time-domain and frequency-domain features. Additionally, inspired by the idea of residual learning, we construct a novel loss function for the constant updating of the multilevel wavelet decomposition parameters.Finally, the IMWDDN is evaluated on the Third China Physiological Signal Challenge Dataset and the MIT-BIH Arrhythmia database. The comparison results show IMWDDN has better detection performance with 98.51% accuracy and a 93.75% F1-macro on average, and its areas of concern are similar to those of an expert diagnosis to a certain extent. Generally, the IMWDDN has good application value in the clinical screening of PVC/SPB heartbeats.

关键词： actual heartbeat classification electrocardiogram interpretable deep network multilevel discrete wavelet decomposition layer SE-Residual block

Directional amine-based solvent extraction for simultaneous enhanced water recovery,salt separation and effective descaling from hypersaline brines

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Frontiers of Environmental Science & Engineering 2024年第3期18卷 83-92页

作者： Yuyao Zhang Litao Jia Jin Zhao Xuming liu Shuyu Dong Chuanyang liu yuanyuan Cui Shougang Research Institute of Technology Beijing 100043China Research Center of Environmental Technology in Water Pollution Source Identification and Precise Supervision School of EnvironmentTsinghua UniversityBeijing 100084China

The feasibility of simultaneous water recovery,salt separation and effective descaling of hypersaline brine was investigated by diisopropylamine(DIPA)-based directional solvent extraction(DSE),using diluted/concentrated seawater with initial saline concentration range of 12–237 g/L at extraction temperatures of 5 and 15℃,respectively.The water recovery shows an obvious boundary at saline concentration of 115 g/L under dual effect of specific water extraction efficiency and extraction cycles.High Cl^(–) ion concentration in product water is in sharp contrast to the nearly complete removal of SO_(4)^(2–)and hardness ions,indicating that DIPA-based DSE process indeed achieved efficient separation and purification of Cl^(–) ion from hypersaline brines.Especially,the radical precipitation of Mg^(2+)and Ca^(2+)ions in form of Mg(OH)_(2)and CaCO_(3)demonstrates effective descaling potential,although it leads to more DIPA residues in dewatered raffinate than product water.Moreover,an exponential correlation between the Cl^(–) removal efficiency and specific water extraction efficiency further reveals the intrinsic relationship of water extraction process and transfer of Cl^(–) ion to the product water.Overall,the study provides a novel approach for integrating the water recovery and separation of Cl^(–) ion from ultra-high-salinity brines with radical precipitation of Mg^(2+)and Ca^(2+) ions in one step.

关键词： Hypersaline brines Directional solvent extraction Salt separation Ca^(2+)and Mg^(2+)descaling

Stage separation of recoverable liquid launch vehicle by using moving pulsating ball analogue for propellant sloshing

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Chinese Journal of Aeronautics 2024年第2期37卷 360-370页

作者： Yu LU Baozeng YUE Bailong HAO Bole MA Feng liu yuanyuan CHANG School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Beijing Institute of Astronautical Systems Engineering Beijing 100076China

In the process of stage separation of recoverable liquid launch vehicles,because of the large amount of residual fuel in the storage tanks,the influence of liquid sloshing on separation safety must be considered.Considering calculation simplicity and operation practicability,the Moving Pulsating Ball Model(MPBM)of large amplitude liquid sloshing is introduced into the calculation of launch vehicle stage separation.Combining the dynamic equation of the model with the energy relationship during"breathing movement",the formula calculating the force of liquid on the rigid body is derived.Compared with the calculations of commercial CFD calculation software,the accuracy of MPBM model is verified.Then,all the external forces and moments are applied to the rigid body of the stages,so that the translational and rotational dynamic equations of the stages are obtained respectively.According to the relative position of the two stages,the geometric shape of the interstage section and the engine of the second stage,the minimum clearance in the separation process can be decided to guarantee that the separation process is safe.

关键词： Moving Pulsating Ball Model(MPBM) Dynamics of stage separation Large amplitude sloshing Recoverable liquid launch vehicle Flight dynamics

Covalently Bonded Ni Sites in Black Phosphorene with Electron Redistribution for Efficient Metal‑Lightweighted Water Electrolysis

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Nano-Micro Letters 2024年第6期16卷 233-245页

作者： Wenfang Zhai Ya Chen Yaoda liu yuanyuan Ma Paranthaman Vijayakumar Yuanbin Qin Yongquan Qu Zhengfei Dai State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi’an 710072People’s Republic of China SSN Research Centre SSN College of EngineeringChennaiTamil Nadu 603110India

The metal-lightweighted electrocatalysts for water splitting are highly desired for sustainable and economic hydrogen energy deployments,but challengeable.In this work,a low-content Ni-functionalized approach triggers the high capability of black phosphorene(BP)with hydrogen and oxygen evolution reaction(HER/OER)bifunctionality.Through a facile in situ electro-exfoliation route,the ionized Ni sites are covalently functionalized in BP nanosheets with electron redistribution and controllable metal contents.It is found that the as-fabricated Ni-BP electrocatalysts can drive the water splitting with much enhanced HER and OER activities.In 1.0 M KOH electrolyte,the optimized 1.5 wt%Nifunctionalized BP nanosheets have readily achieved low overpotentials of 136 mV for HER and 230 mV for OER at 10 mA cm^(−2).Moreover,the covalently bonding between Ni and P has also strengthened the catalytic stability of the Ni-functionalized BP electrocatalyst,stably delivering the overall water splitting for 50 h at 20 mA cm^(−2).Theoretical calculations have revealed that Ni–P covalent binding can regulate the electronic structure and optimize the reaction energy barrier to improve the catalytic activity effectively.This work confirms that Ni-functionalized BP is a suitable candidate for electrocatalytic overall water splitting,and provides effective strategies for constructing metal-lightweighted economic electrocatalysts.

关键词： Black phosphorus Water electrolysis Electrocatalyst Electron redistribution Covalent functionalization

Variations in the Prevalence of Anemia of Varying Severity Among Urban Non-Pregnant Women—China,2021

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China CDC weekly 2024年第10期6卷 175-180页

作者： Xiaoxi liu Bo Wang Sailimai Man Heling Bao yuanyuan Huang Canqing Yu Jun Lyu Linhong Wang Liming Li Hui liu Institute of Medical Information Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijingChina Peking University Health Science Center Meinian Public Health Institute BeijingChina Meinian Institute of Health BeijingChina Peking University Center for Public Health and Epidemic Preparedness&Response BeijingChina Department of Epidemiology and Biostatistics School of Public HealthPeking UniversityBeijingChina Key Laboratory of Epidemiology of Major Diseases(Peking University) Ministry of EducationBeijingChina National Center for Chronic and Non-communicable Disease Control and Prevention Chinese Center for Disease Control and PreventionBeijingChina

Summary What is already known about this topic?Anemia is a significant public health issue affecting women globally.Prior studies in China predominantly concentrated on anemia in pregnant or reproductiveage women,leav... 详细信息

关键词： Anemia anemia China.

Tuning the crystalline and electronic structure of ZrO_(2)via oxygen vacancies and nano-structuring for polysulfides conversion in lithium-sulfur batteries

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Journal of Energy Chemistry 2024年第1期88卷 82-93,I0003页

作者： Shengnan Fu Chaowei Hu Jing Li Hongtao Cui yuanyuan liu Kaihua liu Yanzhao Yang Meiri Wang Shandong Key Laboratory for Chemical Engineering and Processing School of Chemistry&Chemical EngineeringYantai UniversityYantai 264000ShandongChina Key Laboratory for Special Functional Aggregate Materials of Education Ministry School of Chemistry and Chemical EngineeringShandong UniversityJinan 250100ShandongChina

The recent emergence of tetragonal phases zirconium dioxide(ZrO_(2))with vacancies has generated significant interest as a highly efficient and stable electrocatalyst with potential applications in trapping polysulfides and facilitating rapid conversion in lithium-sulfur batteries(LSBs).However,the reduction of ZrO_(2)is challenging,even under strong reducing atmospheres at high temperatures and pressures.Consequently,the limited presence of oxygen vacancies results in insufficient active sites and reaction interfaces,thereby hindering practical implementation.Herein,we successfully introduced abundant oxygen vacancies into ZrO_(2)at the nanoscale with the help of carbon nanotubes(CNTs-OH)through hydrogen-etching at lower temperatures and pressures.The introduced oxygen vacancies on ZrO_(2-x)/CNTs-OH can effectively rearrange charge distribution,enhance sulfiphilicity and increase active sites,contributing to high ionic and electronic transfer kinetics,strong binding energy and low redox barriers between polysulfides and ZrO_(2-x).These findings have been experimentally validated and supported by theory calculations.As a result,LSBs assembled with the ZrO_(2-x)/CNTs-OH modified separators demonstrate excellent rate performance,superior cycling stability,and ultra-high sulfur utilization.Especially,at high sulfur loading of 6 mg cm^(-2),the area capacity is still up to 6.3 mA h cm^(-2).This work provides valuable insights into the structural and functional optimization of electrocatalysts for batteries.

关键词： Lithium-sulfur batteries Oxygen vacancies Zirconium dioxide/carbon nanotubes with–OH Improved redox kinetics Superior cycling stability