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Mass-spring model for elastic wave propagation in multilayered van der Waals metamaterials

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1107-1118页

作者： Yabin JING lifeng wang Yuqiang GAO State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China

Multilayered van der Waals(vdW)materials have attracted increasing interest because of the manipulability of their superior optical,electrical,thermal,and mechanical properties.A mass-spring model(MSM)for elastic wave propagation in multilayered vdW metamaterials is reported in this *** dynamics(MD)simulations are adopted to simulate the propagation of elastic waves in multilayered vdW *** results show that the graphene/MoS_(2)metamaterials have an elastic wave bandgap in the terahertz *** MSM for the multilayered vdW metamaterials is proposed,and the numerical simulation results show that this model can well describe the dispersion and transmission characteristics of the multilayered vdW *** MSM can predict elastic wave transmission characteristics in multilayered vdW metamaterials stacked with different two-dimensional(2D)*** results presented in this paper offer theoretical help for the vibration reduction of multilayered vdW semiconductors.

关键词： multilayered van der Waals(vd W)metamaterial molecular dynamics(MD) mass-spring model(MSM) dispersion relation transmission characteristic

Dynamic characteristics of multi-span spinning beams with elastic constraints under an axial compressive force

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 295-310页

作者： Xiaodong GUO Zhu SU lifeng wang State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A theoretical model for the multi-span spinning beams with elastic constraints under an axial compressive force is *** displacement and bending angle functions are represented through an improved Fourier series,which ensures the continuity of the derivative at the boundary and enhances the *** exact characteristic equations of the multi-span spinning beams with elastic constraints under an axial compressive force are derived by the Lagrange *** efficiency and accuracy of the present method are validated in comparison with the finite element method(FEM)and other *** effects of the boundary spring stiffness,the number of spans,the spinning velocity,and the axial compressive force on the dynamic characteristics of the multi-span spinning beams are *** results show that the present method can freely simulate any boundary constraints without modifying the solution *** elastic range of linear springs is larger than that of torsion springs,and it is not affected by the number of *** an increase in the axial compressive force,the attenuation rate of the natural frequency of a spinning beam with a large number of spans becomes larger,while the attenuation rate with an elastic boundary is lower than that under a classic simply supported boundary.

关键词： multi-span spinning beam elastic constraint improved Fourier series free vibration semi-analytical solution

Flexible Load Participation in Peaking Shaving and Valley Filling Based on Dynamic Price Incentives

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Energy Engineering 2024年第2期121卷 523-540页

作者： lifeng wang Jing Yu Wenlu Ji Nanjing Power Supply Company Nanjing210019China State Grid Jiangsu Electric Power Co. Ltd.Nanjing211103China

Considering the widening of the peak-valley difference in the power grid and the difficulty of the existing fixed time-of-use electricity price mechanism in meeting the energy demand of heterogeneous users at various moments or motivating users,the design of a reasonable dynamic pricing mechanism to actively engage users in demand response becomes imperative for power grid *** this purpose,a power grid-flexible load bilevel model is constructed based on dynamic pricing,where the leader is the dispatching center and the lower-level flexible load acts as the ***,an upper-level day-ahead dispatching model for the power grid is established,considering the lowest power grid dispatching cost as the objective function and incorporating the power grid-side ***,the lower level comprehensively considers the load characteristics of industrial load,energy storage,and data centers,and then establishes a lower-level flexible load operation model with the lowest user power-consuming cost as the objective ***,the proposed method is validated using the IEEE-118 system,and the findings indicate that the dynamic pricing mechanism for peaking shaving and valley filling can effectively guide users to respond actively,thereby reducing the peak-valley difference and decreasing users’purchasing costs.

关键词： Demand response fixed time-of-use electricity price mechanism dynamic price incentives mechanism bi-level model flexible load

Evaluation of the intracellular lipid-lowering effect of polyphenols extract from highland barley in HepG2 cells

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Food Science and Human Wellness 2024年第1期13卷 454-461页

作者： Yijun Yao Zhifang Li Bowen Qin Xingrong Ju lifeng wang College of Food Science and Engineering/Collaborative Innovation Centre for Modern Grain Circulation and Safety Nanjing University of Finance and EconomicsNanjing 210023China

Active ingredients from highland barley have received considerable attention as natural products for developing treatments and dietary supplements against *** practical application,the research of food combinations is more significant than a specific food *** study investigated the lipid-lowering effect of highland barley polyphenols via lipase assay in vitro and HepG2 cells induced by oleic acid(OA).Five indexes,triglyceride(TG),total cholesterol(T-CHO),low density lipoprotein-cholesterol(LDL-C),aspartate aminotransferase(AST),and alanine aminotransferase(ALT),were used to evaluate the lipidlowering effect of highland barley *** also preliminary studied the lipid-lowering mechanism by Realtime fluorescent quantitative polymerase chain reaction(q PCR).The results indicated that highland barley extract contains many components with lipid-lowering effects,such as hyperoside and *** vitro,the lipase assay showed an 18.4%lipase inhibition rate when the additive contents of highland barley extract were 100μg/m *** intracellular lipid-lowering effect of highland barley extract was examined using 0.25 mmol/L OA-induced HepG2 *** results showed that intracellular TG,LDL-C,and T-CHO content decreased by 34.4%,51.2%,and 18.4%,*** and AST decreased by 51.6%and 20.7%compared with the untreated hyperlipidemic HepG2 cells.q PCR results showed that highland barley polyphenols could up-regulation the expression of lipid metabolism-related genes such as PPARγand Fabp4.

关键词： Highland barley Polyphenols extract Lipid-lowering effect HepG2 cells

Slicing of large-size single crystals by ultrafast laser with external stress assistance

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CHINESE OPTICS LETTERS 2024年第8期22卷 081601-081601页

作者： wang, lifeng Liu, Lili wang, Yinan Li, Xun Li, Chenchen Li, Ming Chinese Acad Sci Xian Inst Opt & Precis Mech State Key Lab Transient Opt & Photon Xian 710119 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

The existing single-crystal slicing techniques result in significant material wastage and elevate the production cost of premium-quality thin slices of crystals. Here we report (for the first time, to our knowledge) an approach for vertical slicing of large-size single-crystal gain materials by ultrafast laser. By employing aberration correction techniques, the optimization of the optical field distribution within the high-refractive-index crystal enables the achievement of a continuous laser-modified layer with a thickness of less than 10 mu m, oriented perpendicular to the direction of the laser direction. The compressed focal spot facilitates crack initiation, enabling propagation under external forces, ultimately achieving the successful slicing of a Phi 12 mm crystal. The surface roughness of the sliced Yb:YAG is less than 2.5 mu m. The results illustrate the potential of low-loss slicing strategy for single-crystal fabrication and pave the way for the future development of thin disk lasers.

关键词： single-crystal gain materials ultrafast laser slicing YAG aberration correction FEMTOSECOND LASER DEFORMATION MECHANISM YAG

Preparation of single atom catalysts for high sensitive gas sensing

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International Journal of Extreme Manufacturing 2024年第3期6卷 216-248页

作者： Xinxin He Ping Guo Xuyang An Yuyang Li Jiatai Chen Xingyu Zhang lifeng wang Mingjin Dai Chaoliang Tan Jia Zhang Key Laboratory of Microsystems and Microstructure Manufacturing Ministry of EducationHarbin Institute of TechnologyHarbin 150080People’s Republic of China Institute for Frontier Materials Deakin UniversityWaurn Ponds CampusLocked Bag 20000Victoria 3220Australia School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore Department of Electrical and Electronic Engineering The University of Hong KongPokfulam RoadHong Kong Special Administrative Region of China 999077People’s Republic of China Chongqing Research Institute Harbin Institute of TechnologyChongqing 401120People’s Republic of China

Single atom catalysts(SACs)have garnered significant attention in the field of catalysis over the past decade due to their exceptional atom utilization efficiency and distinct physical and chemical *** the semiconductor-based electrical gas sensor,the core is the catalysis process of target gas molecules on the sensitive *** this context,the SACs offer great potential for highly sensitive and selective gas sensing,however,only some of the bubbles come to the *** facilitate practical applications,we present a comprehensive review of the preparation strategies for SACs,with a focus on overcoming the challenges of aggregation and low *** research efforts have been devoted to investigating the gas sensing mechanism,exploring sensitive materials,optimizing device structures,and refining signal post-processing ***,the challenges and future perspectives on the SACs based gas sensing are presented.

关键词： single atom catalysts preparation sensing mechanism gas sensing

Fully automatic AI segmentation of oral surgery-related tissues based on cone beam computed tomography images

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International Journal of Oral Science 2024年第3期16卷 413-424页

作者： Yu Liu Rui Xie lifeng wang Hongpeng Liu Chen Liu Yimin Zhao Shizhu Bai Wenyong Liu Beijing Yakebot Technology Co. Ltd.BeijingChina School of Mechanical Engineering and Automation Beihang UniversityBeijingChina State Key Laboratory of Oral&Maxillofacial Reconstruction and Regeneration National Clinical Research Center for Oral DiseasesShaanxi Key Laboratory of StomatologyDigital CenterSchool of StomatologyThe Fourth Military Medical UniversityXi’anChina Key Laboratory of Biomechanics and Mechanobiology of the Ministry of Education Beijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijingChina

Accurate segmentation of oral surgery-related tissues from cone beam computed tomography(CBCT)images can significantly accelerate treatment planning and improve surgical *** this paper,we propose a fully automated tissue segmentation system for dental implant ***,we propose an image preprocessing method based on data distribution histograms,which can adaptively process CBCT images with different *** on this,we use the bone segmentation network to obtain the segmentation results of alveolar bone,teeth,and maxillary *** use the tooth and mandibular regions as the ROI regions of tooth segmentation and mandibular nerve tube segmentation to achieve the corresponding *** tooth segmentation results can obtain the order information of the *** corresponding experimental results show that our method can achieve higher segmentation accuracy and efficiency compared to existing *** average Dice scores on the tooth,alveolar bone,maxillary sinus,and mandibular canal segmentation tasks were 96.5%,95.4%,93.6%,and 94.8%,*** results demonstrate that it can accelerate the development of digital dentistry.

关键词： surgery CBCT beam

China's International Hunt for Corrupt Fugitives

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China News Release 2024年第4期 70-71页

作者： wang lifeng the School of Public Administration at Jinlin University the Inner-Party Regulations Research Institute of the Jilin Province Law Society

China has been ramping up efforts to hunt down international fugitives and take this as a supplement and extension of domestic Party conduct and clean government construction and anti-corruption *** January 2014,Chinese President Xi Jinping told the third plenary session of the 18 th Central Commission for Discipline Inspection of the Communist Party of China(CPC)that efforts should be made to hunt down international fugitives.

关键词： Communist struggle forts

Photoswitchable Molecular Recognition Enabled by Dithienylethene-Mediated Structural Changes of Dynamic Covalent Hydrazone Bonds

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CCS Chemistry 2024年第2期6卷 497-506页

作者： lifeng wang Hanxun Zou Hebo Ye Yu Hai Hanwei Lu Junmiao Deng Lei You State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002 College of Chemistry and Material Science Fujian Normal UniversityFuzhou 350007 University of Chinese Academy of Sciences Beijing 100049 Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108

Light-induced recognition,assemblies,and materials are intensive areas of research due to their high spatiotemporal ***,we demonstrated photoswitchable molecular recognition via dithienylethene-triggeredreversible structural regulation of dynamic covalent hydrazone *** combining dithienylethenes and cyclic hemiacetals,the photochemical open-ring and closed-ring forms enabled turningoff and on the creation of awide range of hydrazones when ***-induced bidirectional switching between hydrazones and their cyclization structures promoted by a neighboring carboxyl group was further *** taking advantage of reversible structural changes totoggleon andoff the binding pocket,photoswitchable recognitionofmetal ionswas ***,the construction of an acylhydrazone polymer offered a facile way for light-mediated selective extraction/*** strategies and results reported here should find applications in many contexts,such asdynamicassemblies,molecular switches,and smart materials.

关键词： molecular recognition photoswitch dynamic covalent chemistry hydrazone selective extraction/release