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Enhancing personalized exercise recommendation with student and exercise portraits

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Journal of Electronic Science and Technology 2024年第2期22卷 91-109页

作者： Wei-Wei Gao Hui-Fang ma Yan Zhao Jing Wang Quan-Hong tian College of Computer Science and Engineering Northwest Normal UniversityLanzhou730070China Computer Center of Gansu Province Lanzhou730070China

The exercise recommendation system is emerging as a promising application in online learning scenarios,providing personalized recommendations to assist students with explicit learning *** solutions generally follow a collaborative filtering paradigm,while the implicit connections between students(exercises)have been largely *** this study,we aim to propose an exercise recommendation paradigm that can reveal the latent connections between student-student(exercise-exercise).Specifically,a new framework was proposed,namely personalized exercise recommendation with student and exercise portraits(PERP).It consists of three sequential and interdependent modules:Collaborative student exercise graph(CSEG)construction,joint random walk,and recommendation list ***,CSEG is created as a unified heterogeneous graph with students’response behaviors and student(exercise)***,a joint random walk to take full advantage of the spectral properties of nearly uncoupled markov chains is performed on CSEG,which allows for full exploration of both similar exercises that students have finished and connections between students(exercises)with similar ***,we propose to optimize the recommendation list to obtain different exercise *** analyses of two public datasets,the results demonstrated that PERP can satisfy novelty,accuracy,and diversity.

关键词： Educational data mining Exercise recommend Joint random walk Nearly uncoupled markov chains Optimization Personalized learning

Simulation of magnetization process and Faraday effect of magnetic bilayer films

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Chinese Physics B 2024年第9期33卷 590-597页

作者： Sheng Gao An Du Lei Zhang tian-Guang Li Da-Cheng ma Department of Basic and General Studies Shenyang Institute of Science and TechnologyShenyang 110167China College of Science Northeastern UniversityShenyang 110819China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityShenyang 110819China Office of Academic Research Shenyang Institute of Science and TechnologyShenyang 110167China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy ofSciencesShenyang 110016China Institutes for Robotics and Intelligent manufacturing Chinese Academy of SciencesShenyang110016China

We described ferromagnetic film and bilayer films composed of two ferromagnetic layers coupled through antiferromagnetic interfacial interaction by classical Heisenberg model and simulated their magnetization state,magnetic permeability,and Faraday effect at zero and finite temperature by using the Landau–Lifshitz–Gilbert(LLG)*** results indicate that in a microwave field with positive circular polarization,the ferromagnetic film has one resonance peak while the bilayer film has two resonance ***,the resonance peak disappears in ferromagnetic film,and only one resonance peak emerges in bilayer film in the negative circularly polarized microwave *** the microwave field’s frequency exceeds the film’s resonance frequency,the Faraday rotation angle of the ferromagnetic film is the greatest,and it decreases when the thickness of the two halves of the bilayer is *** the microwave field’s frequency remains constant,the Faraday rotation angle fluctuates with temperature in the same manner as spontaneous magnetization *** a DC magnetic field is applied in the direction of the anisotropic axis of the film,the Faraday rotation angle varies with the DC magnetic field and shows a similar shape of the hysteresis loop.

关键词： magnetic bilayer films magnetic permeability hysteresis loop Faraday effect Landau–Lifshitz– Gilbert (LLG) equation

Additives strategies to improving cycling stability of Li metal batteries by modifying electrode electrolyte interphases

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Progress in Natural Science:materials International 2024年第2期34卷 338-344页

作者： Yuan Li Pengfei Huang Chunyu Cui Xiaoyuan ma Li Chen Zekun Li Linhai Li Yuhong tian School of Biological and Chemical Engineering Guangxi University of Science and Technology School of College of Chemistry and Chemical Engineering Hunan University Isky Future Energy Institute

Li metal batteries（LMBs） have attracted much attention due to the ultra-high theoretical capacity of the Li metal anode（Lma）.However,the uncontrollable dendrites growth and low coulombic efficiency hinder their practical ***,we explore 3,5-difluoropyridine（2F-BD） as a novel electrolyte additive to enable highperformance *** 2F-BD additive participates in and modifies the solvation structure of Li ions by reducing the coordinated number of PF6-at the electrode surface,leading to the formation of a LiF and Li3N-rich solid electrolyte interphase（SEI）.The LiF component increases the robustness of SEI and suppresses the formation of Li dendrites,while the Li3N component facilitates the transportation and reaction kinetics of Li *** a result,the Li‖Li symmetric cell presents a stable cycling performance of up to 500 h at a current density of 1 ma *** coupling with LiFePO4cathode,the obtained full cell achieves high specific capacities of 106.06 ma h g-1and 84.98 ma h g-1at 2.55 ma cm-2and 5.10 ma cm-2,respectively,and maintains a high capacity retention of84.0% after 1000 cycles at 0.13 ma cm-2,with an average cycling CE of 99.58%.

关键词： Li metal batteries Li dendrites Electrolyte additive

Paleoclimatic application of spectral parameters to the eolian red clay of the Jianzha Basin,northeastern margin of the Tibetan Plateau

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Science China Earth Sciences 2024年第6期67卷 1952-1966页

作者： Chaofeng FU ju’e tian Xinwen XU Yougui SONG jun ZUO Feng WANG Lin CHEN Pengfei LI Xiaoke QIANG The School of Earth Science and Resources Chang’an UniversityXi’an 710054China State Key Laboratory of Loess and Quaternary Geology Institute of Earth and EnvironmentCASXi’an 710061China College of Urban and Environmental Science Northwest UniversityXi’an 710069China CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China

Reflectance spectroscopy is rapid,inexpensive,and non-destructive and can provide important information about the mineralogy of rocks and *** measured the reflectance spectroscopy of Miocene red clay deposits on the northeastern margin of the Tibetan Plateau,with the aim of developing a rapid methodology for detecting paleoclimatic *** obtained visible/near-infrared(VNIR)and short-wave infrared(SWIR)spectroscopy data from the red clay in the Jianzha Basin,and analyzed their relationship with independent paleoclimatic records,including mineral contents and environmental magnetic *** results show that the VNIR parameters,including D500,D900,R500,and R900(where D and R represent the depth and reflectance of the absorption peaks around 500 and 900 nm,respectively)are temperature-sensitive and correlated with the magnetic susceptibility,frequency-dependent magnetic susceptibility,and the marine δ^(18)O *** results of frequency-domain analysis of the VNIR parameters show that they reflect climate change on orbital *** parameters,such as AS1400,D1400/D1900 and D1900(where AS represents the asymmetry of the absorption peaks around1400 nm),are correlated with the illite and montmorillonite content,and they are sensitive to the weathering *** spectral parameters of the eolian red clay in the Jianzha Basin reflect regional climatic changes caused by the uplift of the Tibetan Plateau at~8.5 ma and global climatic cooling at~7.2 ma,and thus they are applicable as both regional and global paleoenvironmental indicators.

关键词： Visible/near-infrared spectroscopy Short-wave infrared spectroscopy Paleoclimatic indicators Red clay Tibetan Plateau

Scalable synthesis of lipid nanoparticles for nucleic acid drug delivery using an isometric channel-size enlarging strategy

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Nano Research 2024年第4期17卷 2899-2907页

作者： Zesen ma Haiyang Tong Sijin Lin Li Zhou Demeng Sun Baoqing Li Changlin tian Jiaru Chu Department of Precision machinery and Precision Instrumentation University of Science and Technology of ChinaHefei 230027China Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes University of Science and Technology of ChinaHefei 230027China Science Island Branch Graduate SchoolUniversity of Science and Technology of ChinaHefei 230026China Anhui Provincial Key Laboratory of High Field magnetic Resonance Imaging High Magnetic Field LaboratoryHefei Institute of Physical ScienceChinese Academy of SciencesHefei 230031China Anhui Provincial Engineering Laboratory of Peptide Drugs University of Science and Technology of ChinaHefei 230027China School of Biomedical Engineering Division of Life Sciences and MedicineUniversity of Science and Technology of ChinaSuzhou 215127China

Lipid nanoparticles(LNPs)have emerged as highly effective delivery systems for nucleic acid-based ***,the broad clinical translation of LNP-based drugs is hampered by the lack of robust and scalable synthesis techniques that can consistently produce formulations from early development to clinical *** this work,we proposed a method to achieve scalable synthesis of LNPs by scaling inertial microfluidic mixers isometrically in three ***,a theoretical predictive method,which controls the mixing time to be equal across different chips,is developed to ensure consistent particle size and size distribution of the synthesized *** loaded with small interfering RNA(siRNA)were synthesized at different flow rates,exhibiting consistent physical properties,including particle size,size distribution and encapsulation *** work provides a practical approach for scalable synthesis of LNPs consistently,offering the potential to accelerate the transition of nucleic acid drug development into clinical application.

关键词： lipid nanoparticles nucleic acid delivery microfluidics scalable synthesis consistent particle size

Hemispherical resonator with low subsurface damage machined by small ball-end fine diamond grinding wheel:A novel grinding technique

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Chinese Journal of Aeronautics 2024年第5期37卷 570-585页

作者： Biao QIN Henan LIU Jian CHENG Jinchuan tian Jiangang SUN Zihan ZHOU Chuanzhen ma Mingjun CHEN State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China Center for Precision Engineering Harbin Institute of TechnologyHarbin 150001China

As for the ultra-precision grinding of the hemispherical fused silica resonator,due to the hard and brittle nature of fused silica,subsurface damage(SSD)is easily generated,which enormously influences the performance of such ***,ultra-precision grinding experiments are carried out to investigate the surface/subsurface quality of the hemispherical resonator machined by the small ball-end fine diamond grinding *** influence of grinding parameters on the surface roughness(SR)and SSD depth of fused silica samples is then *** experimental results indicate that the SR and SSD depth decreased with the increase of grinding speed and the decrease of feed rate and grinding *** addition,based on the material strain rate and the maximum undeformed chip thickness,the effect of grinding parameters on the subsurface damage mechanism of fused silica samples is ***,a multi-step ultra-precision grinding technique of the hemispherical resonator is proposed based on the interaction influence between grinding depth and feed ***,the hemispherical resonator is processed by the proposed grinding technique,and the SR is improved from 454.328 nm to 110.449 nm while the SSD depth is reduced by 94%from 40μm to 2.379μ*** multi-step grinding technique proposed in this paper can guide the fabrication of the hemispherical resonator.

关键词： Fused silica Ultra-precision grinding Hemispherical resonator Subsurface damage Grinding technique

Multi-field Coupled Inverse Hall–Petch Relations for Ferroelectric Nanocrystals

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Acta Mechanica Solida Sinica 2024年第1期37卷 139-147页

作者： Xiaodong Zhang Wei Yan Xuhui Lou Yujun Chen Zhihong Zhou Qingyuan Wang Lianhua ma Xiaobao tian Non-Destructive Testing Laboratory School of Quality and Technical SupervisionHebei UniversityBaoding 071002China AVIC Huiyang Aviation Propeller Co. LtdBaoding 071051China Department of Mechanics and Engineering Sichuan UniversityChengdu 610065China Yibin Institute of Industrial Technology Sichuan University Yibin ParkYibin 644000China Research Institute of Interdisciplinary Sciences(RISE) Dongguan University of TechnologyDongguan 523808China School of materials Science and Engineering Dongguan University of TechnologyDongguan 523808China

Tailoring grain size can improve the strength of polycrystals by regulating the proportion of grains to grain boundaries and the interaction *** the grain size decreases to the nanoscale,the deformation mechanism in polycrystals shifts from being primarily mediated by dislocations to deformation occurring within the grains and grain ***,the mechanism responsible for fine-grain strengthening in ferroelectric materials remains unclear,primarily due to the complex multi-field coupling effect arising from spontaneous *** molecular dynamics simulations,we investigate the strengthening mechanism of barium titanate(BaTiO3),with extremely fine-grain *** material exhibits an inverse Hall–Petch relationship between grain size and strength,rooting in the inhomogeneous concentration of atomic strain and grain ***,we present a theoretical model to predict the transition from the inverse Hall–Petch stage to the Hall–Petch stage based on strength variations with size,which aligns well with the simulation *** has been found that the piezoelectric properties of the BaTiO3 are affected by polarization domain switching at various grain *** study enhances our understanding of the atomic-scale mechanisms that contribute to the performance evolution of fine-grain nano-ferroelectric *** also provides valuable insights into the design of extremely small-scale ferroelectric components.

关键词： Ferroelectrics Multi-field coupling Molecular dynamics Fine-grain reinforcement Inverse Hall-Petch effect

Biomimetic microchannel network with functional endothelium formed by sacrificial electrospun fibers inside 3D gelatin methacryloyl(Gelma)hydrogel models

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第1期25卷 79-96页

作者： Haoyu SUN Haiyang ma Li WANG Yang LIU tian HOU Wenjie TANG Qing YU Meiwen AN Meiling WEN Institute of Biomedical Engineering College of Biomedical EngineeringTaiyuan University of TechnologyTaiyuan030024China

Three-dimensional(3D)hydrogel models play a crucial role in tissue engineering for promoting tissue regeneration.A biomimetic microchannel network system in the 3D hydrogel model is necessary for optimal cellular *** report describes the preparation of a biomimetic hydrogel scaffold with an internal microchannel network,using electrospinning techniques and the sacrificial template method for 3D cell *** and cavities were created within the gelatin methacryloyl(Gelma)hydrogel by sacrificing polyvinyl alcohol(PVA)electrospun fibers(>10µm),resulting in the creation of microvessel-like *** characterizations,swelling properties,and biodegradation analysis were conducted to investigate the feasibility of a biomimetic microchannel network hydrogel scaffold for 3D cell culture *** to pure Gelma hydrogel,the hydrogel with microchannels promoted cell proliferation,adhesion,and endothelial tube ***,the results confirmed that the biomimetic microchannel network scaffold had a major impact on the distribution and arrangement of human umbilical vein endothelial cells(HUVECs)and can enable the formation of artificial microvasculature by the culture of HUVECs and cell media perfusion.

关键词： Biomimetic scaffold Photocrosslinking Microchannel network Tissue engineering Artificial microvascular

Multifunctional dual-anion compensation of amphoteric glycine hydrochloride enabled highly stable perovskite solar cells with prolonged carrier lifetime

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Nano Research 2024年第6期17卷 5131-5137页

作者： Lina Qin Mengfei Zhu Yuren Xia Xingkai ma Daocheng Hong Yuxi tian Zuoxiu Tie Zhong Jin State Key Laboratory of Coordination Chemistry MOE Key Laboratory of Mesoscopic ChemistryMOE Key Laboratory of High Performance Polymer Materials and TechnologyJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China Nanjing Tieming Energy Technology Co.Ltd. Nanjing 210093China Suzhou Tierui New Energy Technology Co.Ltd. Suzhou 215228China

Throughout years,the two-step spin-coating process is the most common method to prepare organic lead halide perovskite ***,the short reaction time of dropping the solution at the second step means that PbI2 cannot be completely transformed into perovskite *** solve this problem,we report the introduction of glycine hydrochloride(GlyHCl)into the second step of the two-step spin-coating process to prepare a FA_(0.9)ma_(0.1)PbI_(3-x)%-GlyHCl perovskite material(namely FAma-x%-GlyHCl,where FA=formamidinium,ma=methylammonium,and x%stands for the molar ratio of GlyHCl added in FA iodide/ma iodide(FAI/maI)precursor solution).The Cl−ion in GlyHCl assists the formation ofα-phase perovskite,and the-COO−group coordinates with Pb2+cation in a bridging way,making up for the anion vacancy in perovskite lattice and resulting in high absorption *** perovskite solar cells(PSCs)based on FAma-9%-GlyHCl achieve a long carrier lifetime(527.0 ns),a photoelectric conversion efficiency(PCE)of 19.40%and good thermal stability,maintaining 85.8%of the initial PCE after being continuously heated at 60℃for 500 *** study helps to solve the problem of incomplete reaction in the two-step spin-coating process and puts forward a new solution for preparing high coverage perovskite films with large grain size.

关键词： dual-anion compensation glycine hydrochloride perovskite solar cells carrier lifetime thermal and moisture stability