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A new integrated model of deformation resistance and its application in prediction of rolling force of a thick plate

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Journal of Iron and Steel Research International 2024年第4期31卷 882-893页

作者： Shun-hu zhang Yan Li Li-zhi che Wen-hao Tian Shagang School of Iron and Steel Soochow UniversitySuzhou 215021JiangsuChina

The prediction accuracy of existing models of the rolling force of a thick plate is always very *** address this problem,a high-precision genetic algorithm-backpropagation network(GA-BP)model of deformation resistance was built,and its integration with the traditional fitted model was further ***,a novel rolling force model was obtained by embedding the integration model of deformation resistance in the original model of rolling *** to this research idea,the industrial data are normalized at *** this basis,the interactions among the process parameters were disclosed through the variance analysis,and then described by various virtual *** factors are set as part of input ***,the optimal structure of the GA-BP model of deformation resistance was determined and an integration model of deformation resistance was ***,a novel rolling force model is obtained by substituting the traditional fitted deformation resistance into the Sims model with the integration model of the deformation *** results proves that the introduction of virtual factors can increase the hit rate of±5%from 75.8%to 78%and can reduce the root mean square error from 4.72%to 4.48%.Besides,it is found that the mean relative error of the traditional fitted deformation resistance is 0.142,while that of the modified deformation resistance is only *** addition,the mean relative error in the original rolling force model is 0.145,while that of the present model is only 0.03.

关键词： Integration model-Deformation resistance Variance analysis Virtual factor Genetic algorithm-backpropagation network model

Evaluating the performance and influencing factors of three portable black carbon monitors for field measurement

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Journal of Environmental Sciences 2024年第5期139卷 320-333页

作者： Liqing Wu Yicheng Shen Fei che Yuzhe zhang Jian Gao Chong Wang State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China Jinan Ecological Environmental Protection Grid-Based Supervision Center Jinan 250013China

Black carbon(BC)is associated with adverse human health and climate *** BC spatial distribution imperatively requires low-cost and portable *** portable BC monitors are commercially available,but their accuracy and reliability are not always satisfactory during continuous field *** study evaluated three models of portable black carbon monitors,C12,MA350 and DST,and investigates the factors that affect their *** monitors were tested in urban Beijing,where portable devices running for one month alongside a regular-size reference aethalometer *** study considers several factors that could influence the monitors'performance,including ambient weather,aerosol composition,loading artifacts,and built-in *** results show that MA350and DST present considerable discrepancies to the reference instrument,mainly occurring at lower concentrations(0-500 ng/m^(3))and higher concentrations(2500-8000 ng/m^(3)),*** discrepancies were likely caused by the anomalous noise of MA350 and the loading artifacts of *** study also suggests that the ambient environment has limited influence on the monitors'performance,but loading artifacts and accompanying compensation algorithms can result in unrealistic *** on the evaluation,the study suggests that C12 is the best choice for unsupervised field measurement,DST should be used in scenarios where frequent maintenance is available,and MA350 is suitable for research purposes with post-processing *** study highlights the importance of assigning portable BC monitors to appropriate applications and the need for optimized real-time compensation algorithms.

关键词： Black carbon Aethalometer Loading artifact Performance evaluation Portable device

Chiral mesostructured hematite with temperature-independent magnetism due to spin confinement

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Nano Research 2024年第3期17卷 2019-2024页

作者： Baiwen zhang Jing Ai Yingying Duan Te Bai Lu Han Shunai che School of Physics Science and Engineering Tongji UniversityShanghai 200092China School of chemistry and chemical Engineering Tongji UniversityShanghai 200092China Wuxi Vocational College of Science and Technology Wuxi 214028China School of chemistry and chemical Engineering Frontiers Science Center for Transformative MoleculesState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China

Hematite(α-Fe_(2)O_(3))is known to undergo conversion from weak ferromagnetic to antiferromagnetic as the temperature decreases below the Morin temperature(TM=250 K)due to spin moment rotation occurring during the Morin transition(MT).Herein,we endowed hematite with mesostructured chirality to maintain weak ferromagnetism without *** mesostructured hematite(CMH)nanoparticles were prepared by a hydrothermal method with glutamic acid(Glu)as the symmetry-breaking *** triangular bipyramidal CMH nanoparticles were composed of helically cleaved nanoflakes with twisted crystal ***-cooled(FC)magnetization measurements showed that the magnetic moments of CMH were stabilized without MT within the temperature range of 10–300 *** loop measurements confirmed the weak ferromagnetism of *** enhanced Dzyaloshinskii–Moriya interaction(DMI)was speculated to be responsible for the temperature-independent weak ferromagnetism,in which the spin configuration would be confined with canted antiferromagnetic coupling due to the mesostructured chirality of CMH.

关键词： hematite chiral mesostructure Dzyaloshinskii–Moriya interaction weak ferromagnetism antiferromagnetic material temperature-independent magnetism

Efficient piezo-assisted near-infrared-light-driven Cr(Ⅵ)reduction over Bi_(2)S_(3) nanowires transformed from ultrathin Bi_(2)WO_(6) nanosheets

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Rare Metals 2024年第9期43卷 4333-4343页

作者： Qiang zhang Yuan-Hao cheng Wei Liu Hui-Nan che Yan-Hui Ao Key Laboratory of Integrated Regulation and Resource Development On Shallow Lakes Ministry of EducationCollege of EnvironmentHohai UniversityNanjing 210098China

The utilization of piezo-photocatalytic technol ogy for environmental remediation under full spectrum solar light is promising but still ***,one dimensional Bi_(2)S_(3)nanowires,which can utilize both mechanical energy and near-infrared(NIR)light to remov hexavalent chromium(Cr(Ⅵ))efficiently,were synthe sized by a restrained growth *** reaction rat constants of Cr(Ⅵ)reduction in piezo-photocatalyti process under NIR(800–2500 nm)reached 0.334 min^(-1)which were 3.2 and 12.4 times as that of single piezo and photocatalytic *** formation of polarized electri fields and one-dimensional structure allow ultrafast sepa ration of charge carriers,thereby promoting the catalyti ***,due to the strong penetrability o NIR light,the piezo-photocatalysis performance in turbid solutions under NIR light(0.188 min^(-1))was even com parable to that under visible light(0.186 min^(-1)).Thi study provides a new concept on the development of piezo photocatalytic technology for environmental remediation by utilization of NIR light and natural mechanical energy.

关键词： Piezo-photocatalysis NIR light Bi_(2)S_(3)nanowires Cr(Ⅵ)

Mechanical properties and damage evolution characteristics of waste tire steel fiber-modified cemented paste backfill

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International Journal of Mining Science and Technology 2024年第7期34卷 909-924页

作者： Shenggen Cao Chiyuan che Yun zhang Changhao Shan Yang Liu Changzheng Zhao Shuyu Du State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources School of MinesChina University of Mining and TechnologyXuzhou 221116China College of Energy Engineering Xi’an University of Science&TechnologyXi’an 710054China

During the process of constructional backfill mining,the cemented paste backfill(CPB)typically exhibits a high degree of brittleness and limited resistance to *** this study,the mechanical and damage evolution characteristics of waste tire steel fiber(WTSF)-modified CPB were studied through uniaxial compression tests,acoustic emission(AE)tests,and scanning electron microscopy(SEM).The results showed that the uniaxial compressive strength(UCS)decreased when the WTSF content was 0.5%,1%,and 1.5%.When the WTSF content reached 1%,the UCS of the modified CPB exhibited a minimal decrease(0.37 MPa)compared to that without *** the WTSF content was 0.5%,1%,and 1.5%,peak strain of the WTSF-modified CPB increased by 18%,31.33%,and 81.33%,while the elastic modulus decreased by 21.31%,26.21%,and 45.42%,*** addition of WTSF enhances the activity of AE events in the modified CPB,resulting in a slower progression of the entire failure *** the failure,the modified CPB retained a certain level of load-bearing ***,the failure of the CPB was dominated by tensile *** the addition of WTSF,a gradual increase in the proportion of tensile cracks was observed upon loading the modified CPB sample to the pore compaction *** three-dimensional localization of AE events showed that the WTSF-modified CPB underwent progressive damage during the loading,and the samples still showed good integrity after ***,the response relationship between energy evolution and damage development of WTSF-modified CPB during uniaxial compression was analyzed,and the damage constitutive model of CPB samples with different WTSF contents was *** study provides a theoretical basis for the enhancement of CPB modified by adding WTSF,serving as a valuable reference for the design of CPB constructional backfill.

关键词： Constructional backfill Cemented paste backfill Waste tire steel fiber Acoustic emission Damage characteristics

Tracking Regulatory Mechanism of Trace Fe on Graphene Electromagnetic Wave Absorption

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Nano-Micro Letters 2024年第4期16卷 79-96页

作者： Kaili zhang Yuhao Liu Yanan Liu Yuefeng Yan Guansheng Ma Bo Zhong Renchao che Xiaoxiao Huang School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001People’s Republic of China MIIT Key Laboratory of Advanced Structural‑Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001People’s Republic of China School of Materials Science and Engineering Harbin Institute of Technology at WeihaiWeihai 264209People’s Republic of China Laboratory of Advanced Materials Shanghai Key Lab of Molecular Catalysis and Innovative MaterialsFudan UniversityShanghai 200438People’s Republic of China

Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the first time, the reduced graphene oxide(RGO) based absorbers are developed with regulatory absorption properties and the absorption mechanism of RGO is mainly originated from the carrier injection behavior of trace metal Fe nanosheets on graphene. Accordingly, the minimum reflection loss(RLmin) of Fe/RGO-2composite reaches-53.38 dB(2.45 mm), and the effective absorption bandwidth achieves 7.52 GHz(2.62 mm) with lower filling loading of 2 wt%. Using off-axis electron hologram testing combined with simulation calculation and carrier transport property experiments, we demonstrate here the carrier injection behavior from Fe to graphene at the interface and the induced charge accumulation and rearrangement, resulting in the increased interfacial and dipole polarization and the conductance loss. This work has confirmed that regulating the dielectric property of graphene itself by adding trace metals can not only ensure good impedance matching, but also fully exploit the dielectric loss ability of graphene at low filler content,which opens up an efficient way for designing lightweight absorbers and may be extended to other types materials.

关键词： Reduced graphene oxide Fe nanosheets Dielectric loss Electromagnetic wave absorption

Quantification of irrigation water transport processes in ZiZiphus jujuba garden using water stable isotopes

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Journal of Mountain Science 2024年第10期21卷 3263-3274页

作者： ZHONG Xiaofei zhang Mingjun che Cunwei LIU Zechen LI Beibei zhang Yuanyuan College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730000China Key Laboratory of Resource Environment and Sustainable Development of Oasis Lanzhou 730000China

ZiZiphus jujuba,which is native to China,has become one of the main crops widely planted in the western Loess Plateau because of its drought and flood-tolerance,adaptability,and higher nutritional value of the *** irrigation water infiltration in *** gardens is complex,and understanding its mechanisms is essential for efficient water use and sustainable *** knowledge helps ensure the long-term success of jujuba *** paper describes a field experiment that investigates the infiltration process of irrigation water from *** garden and quantifies the contribution of irrigation water to soil water at different depths using the MixSIAR *** to the FC(Field water holding Capacity)of ***,irrigation experiments with three volumes of 80%FC,60%FC,and 40%FC are set up in this *** study finds that water retention is better in *** garden soils with a higher proportion of coarse gravel in the soil particle *** water content exhibits a gradient change after irrigation,with deeper wetting front transport depth observed with increased irrigation ***,there is correlation between soil temperature and soil water *** soil water in *** garden generally exhibits a preferential flow signal in the 0-40 cm *** 40 cm,a piston flow pattern *** rate of soil water infiltration increases with the amount of irrigation *** the 0-40 cm range of the soil vertical profile,irrigation water was the main contributor to soil *** demonstrated flexibility in water uptake,primarily absorbing soil water at depths of 0-40 *** optimal growth of *** at this stage,40%FC irrigation is *** results are expected to be valuable future irrigation practices and land use planning for *** garden in arid zones,supporting sustainable agricultural development and water management.

关键词： Water stable isotopes Different irrigation volumes ZiZiphus jujuba Irrigation water infiltration process MixSIAR model

Novel modular quasi-zero stiffness vibration isolator with high linearity and integrated fluid damping

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Frontiers of Mechanical Engineering 2024年第1期19卷 105-128页

作者： Wei zhang Jixing che Zhiwei HUANG Ruiqi GAO Wei JIANG Xuedong cheN Jiulin WU State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

Passive vibration isolation systems have been widely applied due to their low power consumption and high ***,the design of vibration isolators is usually limited by the narrow space of installation,and the requirement of heavy loads needs the high supporting stiffness that leads to the narrow isolation frequency *** improve the vibration isolation performance of passive isolation systems for dynamic loaded equipment,a novel modular quasi-zero stiffness vibration isolator(MQZS-VI)with high linearity and integrated fluid damping is *** MQZS-VI can achieve high-performance vibration isolation under a constraint mounted space,which is realized by highly integrating a novel combined magnetic negative stiffness mechanism into a damping structure:The stator magnets are integrated into the cylinder block,and the moving magnets providing negative-stiffness force also function as the piston supplying damping force *** analytical model of the novel MQZS-VI is established and verified *** effects of geometric parameters on the characteristics of negative stiffness and damping are then elucidated in detail based on the analytical model,and the design procedure is proposed to provide guidelines for the performance optimization of the ***,static and dynamic experiments are conducted on the *** experimental results demonstrate the proposed analytical model can be effectively utilized in the optimal design of the MQZS-VI,and the optimized MQZS-VI broadened greatly the isolation frequency band and suppressed the resonance peak simultaneously,which presented a substantial potential for application in vibration isolation for dynamic loaded equipment.

关键词： vibration isolation quasi-zero stiffness damping magnetic spring integrated design

Cross-border E-commerce and China's Exports during the COVID-19 Pandemic

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China & World Economy 2024年第3期32卷 215-242页

作者： Yi che Meng Yuan Yan zhang Lin Zhao School of Business East China University of Science and TechnologyChina School of Business Xiangtan UniversityChina School of Economics Shanghai University of Finance and EconomicsChina

China's exports experienced a rapid recovery after the outbreak of the 2019 COVID-19 pandemic.A primary engine was cross-border e-commerce(CBEC)trade,which bucked the downward export trend during the *** exploring the variation in the number of CBEC comprehensive pilot zones across provinces,we identified the causal impact of CBEC on exports using monthly province-product-destination data for 2019 and *** found strong and robust evidence that CBEC contributed to exports during the pandemic by promoting the expansion of incumbent exports(intensive margin)rather than through the expansion of product categories and exporting partners(extensive margin).Specifically,higher pandemic risk suppressed the role of CBEC at the intensive margin while enhancing it at the extensive *** to developed countries benefited more from CBEC,both intensively and *** with final products,a larger number of intermediate products were exported through CBEC after the outbreak of the pandemic.

关键词： China's exports COVID-19 pandemic cross-border e-commerce extensive margin of trade intensive margin of trade