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Auto-parametric resonance of a continuous-beam-bridge model under two-point periodic excitation:an experimental investigation and stability analysis

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 445-454页

作者： Li Yuchun Shen Chao Liu Wei Li dong Department of Hydraulic Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

The auto-parametric resonance of a continuous-beam bridge model subjected to a two-point periodic excitation is experimentally and numerically investigated in this *** auto-parametric resonance experiment of the test model is conducted to observe and measure the auto-parametric resonance of a continuous beam under a two-point excitation on *** parametric vibration equation is established for the test model using the finite-element *** auto-parametric resonance stability of the structure is analyzed by using Newmark's method and the energy-growth exponent *** effects of the phase difference of the two-point excitation on the stability boundaries of auto-parametric resonance are studied for the test *** with the experiment,the numerical instability predictions of auto-parametric resonance are consistent with the test phenomena,and the numerical stability boundaries of auto-parametric resonance agree with the experimental *** a continuous beam bridge,when the ratio of multipoint excitation frequency(applied to the columns)to natural frequency of the continuous girder is approximately equal to 2,the continuous beam may undergo a strong auto-parametric *** with the present experiment and analysis,a hypothesis of Volgograd Bridge's serpentine vibration is discussed.

关键词： auto-parametric resonance continuous beam bridge model two-point excitation experimental investigation stability analysis vibration of Volgograd Bridge

Macro-superlubricity in sputtered MoS_(2)-based films by decreasing edge pinning effect

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Friction 2024年第1期12卷 52-63页

作者： Chunmeng dong dong JIANG Yanlong FU Desheng WANG Qinqin WANG Lijun WENG Ming HU Xiaoming GAO Jiayi SUN State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

To date,MoS_(2) can only be achieved at *** pinning effect caused by structure defects is the most obvious barrier to expand the size of structural superlubricity to ***,we plan to pin edge planes of MoS_(2) with nanospheres,and then the incommensurate structure can be formed between adjacent rolling nanoparticles to reduce *** sputtered MoS_(2) film was prepared by the physical vapor deposition(PVD)in *** enough Cu_(2)O nanospheres(~40 nm)were generated in situ at the edge plane of MoS_(2) layers by liquid phase *** incommensurate structure(mismatch angle(θ)=8°)caused by MoS_(2) layers was formed before *** friction coefficient of the films(5 N,1,000 r/min)was~6.0×10^(−3) at the *** friction,MoS_(2) layers pinned on numerous of Cu_(2)O nanoparticles reduced its edge pinning effect and decreased ***,much more incommensurate was formed,developing macro-superlubricity.

关键词： sputtered MoS_(2)film Cu_(2)O nanospheres edge pinning effect macro-superlubricity

Picotesla fiberized diamond-based AC magnetometer

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Photonics Research 2024年第6期12卷 1250-1261页

作者： SHAO-CHUN ZHANG YONG LIU LONG-KUN SHAN XUE-dong GAO JIA-QI GENG CUI YU YANG dong XIANG-dong CHEN GUANG-CAN GUO FANG-WEN SUN CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China National Key Laboratory of ASIC Hebei Semiconductor Research InstituteShijiazhuang 050051China Electric Power Quantum Sensing Joint Laboratory of Anhui Province State Grid Anhui Electric Power Research InstituteHefei 230601China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

Portable quantum sensors are crucial for developing practical quantum sensing and metrology *** nitrogen-vacancy(NV)centers in diamonds have emerged as one of the most promising candidates for compact quantum ***,due to the difficulty of coherently controlling the ensemble spin and noise suppression in a large volume,it often faces problems such as reduced sensitivity and narrowed bandwidth in integrated lensless ***,we propose a fluorescence signal treatment method for NV spin ensemble manipulation by the exponential fitting of spin polarization processes,instead of integrating the photon *** enables spin state readout with a high signal-to-noise ratio and applies to the pulse sensing protocols for large-volume NV *** on this,we further developed a fiberized diamond-based AC *** an XY8-N dynamical decoupling pulse sequence,we demonstrated a T_(2)-limited sensitivity of 8pT/√Hz and T_(1)-limited frequency resolution of 90 Hz over a wide frequency band from 100 kHz to 3 *** integrated diamond sensor leverages quantum coherence to achieve enhanced sensitivity in detecting AC magnetic fields,making it suitable for implementation in a compact and portable endoscopic sensor.

关键词： magnetometer quantum ensemble

Proposal for valleytronic materials:Ferrovalley metal and valley gapless semiconductor

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Frontiers of physics 2024年第2期19卷 131-139页

作者： San-dong Guo Yu-Ling Tao Guangzhao Wang Shaobo Chen dong Huang Yee Sin Ang School of Electronic Engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China Key Laboratory of Extraordinary Bond Engineering and Advanced Materials Technology of Chongqing School of Electronic Information EngineeringYangtze Normal UniversityChongqing 408100China College of Electronic and Information Engineering Anshun UniversityAnshun 561000China Science Mathematics and Technology(SMT)Singapore University of Technology and Design(SUTD)8 Somapah RoadSingapore 487372Singapore

Valleytronic materials can provide new degrees of freedom to future electronic *** this work,the concepts of the ferrovalley metal(FVM)and valley gapless semiconductor(VGS)are proposed,which can be achieved in valleytronic bilayer systems by electric field *** valleytronic bilayer systems,the interaction between out-of-plane ferroelectricity and A-type antiferromagnetism can induce layer-polarized anomalous valley Hall(LP-AVH)*** K and−K valleys of FVM are both metallic,and electron and hole carriers simultaneously *** the extreme case,the FVM can become VGS by analogizing spin gapless semiconductor(SGS).Moreover,it is proposed that the valley splitting enhancement and valley polarization reversal can be achieved by electric field engineering in valleytronic bilayer *** the bilayer RuBr_(2)as an example,our proposal is confirmed by the first-principle *** FVM and VGS can be achieved in bilayer RuBr_(2)by applying electric *** appropriate electric field range,increasing electric field can enhance valley splitting,and the valley polarization can be reversed by flipping electric field *** effectively tune valley properties by electric field in bilayer systems,the parent monolayer should possess out-of-plane magnetization,and have large valley *** results shed light on the possible role of electric field in tuning valleytronic bilayer systems,and provide a way to design the ferrovalley-related material by electric field.

关键词： valleytronics electric field bilayer

High-speed PGC demodulation model and method with subnanometer displacement resolution in a fiber-optic micro-probe laser interferometer

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Photonics Research 2024年第5期12卷 921-931页

作者： YISI dong WENWEN LI JiNRAN ZHANG WENRUI LUo HAIJIN FU XU XING PENGCHENG HU YONGKANG dong JIUBIN TAN Center of Ultra-precision Optoelectronic Instrument Harbin Institute of TechnologyHarbin 150080China Key Laboratory of Ultra-precision Intelligent Instrumentation(Harbin Institute of Technology) Ministry of Industry and Information TechnologyHarbin 150080China National Key Laboratory of Science and Technology on Tunable Laser Harbin Institute of TechnologyHarbin 150001China

As the key of embedded displacement measurement,a fiber-optic micro-probe laser interferometer(FMI)is of great interest in developing high-end equipment as well as precision ***,conventional phasegenerated carrier(PGC)approaches are for low-speed scenes and local error analysis,usually neglecting the global precision analysis and dynamic effect of system parameters under high-speed measurement,thus hindering their broad *** present a high-speed PGC demodulation model and method to achieve subnanometer displacement measurement precision in *** model includes a global equivalent resolution analysis and revelation of the demodulation error *** this model,the failure issues regarding the PGC demodulation method under high speed and large range are ***,an ultra-precision PGC demodulation algorithm based on the combination of static and dynamic delay adaptive regulation is proposed to enable high-speed and large-range displacement *** this paper,the proposed model and algorithm are validated through simulation and experimental *** results demonstrate a displacement resolution of 0.1 nm with a standard deviation of less than 0.5 nm when measuring at a high velocity of 1.5 m/s—nearly a tenfold increase of the latest study.

关键词： interferometer fiber displacement

Time-space multiplexed photonic-electronic digital multiplier

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Photonics Research 2024年第3期12卷 499-504页

作者： WENKAI ZHANG BO WU WENTAO GU JUNWEI CHENG HAILONG ZHOU LIAO CHEN WENCHAN dong JIANJI dong XINLIANG ZHANG Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Optical computing has shown immense application prospects in the post-Moore ***,as a crucial component of logic computing,the digital multiplier can only be realized on a small scale in optics,restrained by the limited functionalities and inevitable loss of optical *** this paper,we propose a time-space multiplexed architecture to realize large-scale photonic-electronic digital multiplication.

关键词： multiplier electronic restrained

Stabilizing High-Nickel Cathodes via Interfacial Hydrogen Bonding Effects Using a Hydrofluoric Acid-Scavenging Separator

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Engineering 2024年第8期39卷 117-126页

作者： Shijie Zhong Liwei dong Botao Yuan Yueyao dong Qun Li Yuanpeng Ji Yuanpeng Liu Jiecai Han Weidong He National Key Laboratory of Science and Technology on Advanced Composites in Special Environments &Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin 150080China MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001China Chongqing Research Institute Harbin Institute of TechnologyChongqing 401151China School of Mechanical Engineering Chengdu UniversityChengdu 610106China

Nickel-rich layered Li transition metal oxides are the most promising cathode materials for high-energydensity Li-ion ***,they exhibit rapid capacity degradation induced by transition metal dissolution and structural reconstruction,which are associated with hydrofluoric acid(HF)generation from lithium hexafluorophosphate *** potential for thermal runaway during the working process poses another *** are promising components to alleviate the aforementioned ***,an ultrathin double-layered separator with a 10 lm polyimide(PI)basement and a 2 lm polyvinylidene difluoride(PVDF)coating layer is designed and fabricated by combining a nonsolvent induced phase inversion process and coating *** PI skeleton provides good stability against potential thermal shrinkage,and the strong PI-PVDF bonding endows the composite separator with robust structural integrity;these characteristics jointly contribute to the extraordinary mechanical tolerance of the separator at elevated ***,unique HF-scavenging effects are achieved with the formation of-CO…H-F hydrogen bonds for the abundant HF coordination sites provided by the imide ring;hence,the layered Ni-rich cathodes are protected from HF attack,which ultimately reduces transition metal dissolution and facilitates long-term cyclability of the Ni-rich ***||NCM811 batteries(where“NCM”indicates LiNi_(x)Co_(y)Mn_(1-x-y)O_(2))with the proposed composite separator exhibit a 90.6%capacity retention after 400 cycles at room temperature and remain sustainable at 60℃with a 91.4%capacity retention after 200 *** adopting a new perspective on separators,this study presents a feasible and promising strategy for suppressing capacity degradation and enabling the safe operation of Ni-rich cathode materials.

关键词： Nickel-rich cathodes Composite separator HF scavenging Transition metal dissolution Long-term cyclability

A semi-analytical model for coupled flow in stress-sensitive multi-scale shale reservoirs with fractal characteristics

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Petroleum Science 2024年第1期21卷 327-342页

作者： Qian Zhang Wen-dong Wang Yu-Liang Su Wei Chen Zheng-dong Lei Lei Li Yong-Mao Hao Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao266580ShandongChina School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Shale Oil Development Branch Changqing Oilfield CompanyPetroChinaQingyang745708GansuChina PetroChina Research Institute of Petroleum Exploration&Development Beijing100083China

A large number of nanopores and complex fracture structures in shale reservoirs results in multi-scale flow of oil. With the development of shale oil reservoirs, the permeability of multi-scale media undergoes changes due to stress sensitivity, which plays a crucial role in controlling pressure propagation and oil flow. This paper proposes a multi-scale coupled flow mathematical model of matrix nanopores, induced fractures, and hydraulic fractures. In this model, the micro-scale effects of shale oil flow in fractal nanopores, fractal induced fracture network, and stress sensitivity of multi-scale media are considered. We solved the model iteratively using Pedrosa transform, semi-analytic Segmented Bessel function, Laplace transform. The results of this model exhibit good agreement with the numerical solution and field production data, confirming the high accuracy of the model. As well, the influence of stress sensitivity on permeability, pressure and production is analyzed. It is shown that the permeability and production decrease significantly when induced fractures are weakly supported. Closed induced fractures can inhibit interporosity flow in the stimulated reservoir volume (SRV). It has been shown in sensitivity analysis that hydraulic fractures are beneficial to early production, and induced fractures in SRV are beneficial to middle production. The model can characterize multi-scale flow characteristics of shale oil, providing theoretical guidance for rapid productivity evaluation.

关键词： Multi-scale coupled flow Stress sensitivity Shale oil Micro-scale effect Fractal theory

On hypersurfaces of H2×H2

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Science China Mathematics 2024年第2期67卷 339-366页

作者： dong Gao Hui Ma Zeke Yao School of Science Beijing University of Civil Engineering and Architecture Department of Mathematical Sciences Tsinghua University

In this paper, we study hypersurfaces of H2× H2. We first classify the hypersurfaces with constant principal curvatures and constant product angle functions. Then we classify homogeneous hypersurfaces and isoparametric hypersurfaces, respectively. Finally, we classify the hypersurfaces with at most two distinct constant principal curvatures, as well as those with three distinct constant principal curvatures under some additional conditions.

关键词： constant principal curvature homogeneous hypersurface isoparametric hypersurface 53C42 53B25 53C40