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state-of-the-art on the anchorage performance of rock bolts subjected to shear load

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International Journal of Coal science & Technology 2024年第1期11卷 1-30页

作者： yu chen Haodong Xiao school of Civil Engineering Sun Yat-sen UniversityZhuhai519082China

Rock bolts are extensively utilized in underground engineering as a means of offering support and stability to rock masses in tunnels,mines,and other underground *** environments of high ground stress,faults or weak zones can frequently arise in rock formations,presenting a significant challenge for engineering and potentially leading to underground engineering *** bolts serve as a crucial structural element for the transmission of tensile stress and are capable of withstanding shear loads to prevent sliding of weak zones within rock ***,a complete understanding of the behavior of rock bolts subjected to shear loads is *** paper presents a state-of-the-art review of the research progress of rock bolts subjected to shear load in three categories:experiment,numerical simulation,and analytical *** review focuses on the research s.udies and developments in this area since the 1970s,providing a comprehensive overview of numerous factors that influence the anchorage performance of rock *** factors include the diameter and angle of the rock bolt installation,rock strength,grouting material,bolt material,borehole diameter,rock bolt preload,normal stress,joint surface roughness and joint expansion *** paper reviews the improvement of mechanical parameter setting in numerical simulation of rock bolt ***,it delves into the optimization of the analytical model concerning rock bolt shear theory,approached from the perspectives of both Elastic foundation beam theory coupled with Elastoplasticity theory and structural mechanic *** significance of this review lies in its ability to provide insights into the mechanical behavior of rock *** paper also highlights the limitations of current research and guidelines for further research of rock bolts.

关键词： Rock bolt shear load shear test Numerical simulation Analytical model

Mott insulator-density ordered superfluid transition and‘shamrock transition’in a frustrated triangle lattice

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Communications in Theoretical Physics 2024年第3期76卷 157-164页

作者： Ce Wang yu chen school of Physics science and Engineering Tongji UniversityShanghai200092China Institute for Advanced s.udy Tsinghua UniversityBeijing100084China Graduate school of China Academy of Engineering Physics Beijing100193China

Density order is.usually a consequence of the competition between long-range and short-range *** we report a density ordered superfluid emergent from a homogeneous Mott insulator due to the competition between frustrations and local *** transition is found in a Bose–Hubbard model on a frustrated triangle lattice with an extra pairing ***,we find a quantum phase transition between two different density ordered superfluids,which is beyond the Landau–Ginzburg(LG)paradigm.A u(1)symmetry is emergent at the critical point,while the symmetry in each density ordered superfluid is Z_(2)×Z_(3).We call the transition a‘shamrock transition’,due to its degenerate ground state in the parameter space being a shamrock-like curve rather than a circle in an LG-type *** low energy theories are established for the two transitions mentioned above and we find their resemblance and differences with clock models.

关键词： frustrated magnets superfluid mott insulator density wave ordered phase clock model

Design and Gait Planning of a Worm-inspired Metameric Robot for Pipe Crawling

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Journal of Bionic Engineering 2024年第3期21卷 1265-1277页

作者： yu Liu Qingbiao shi Zhen chen Pen-Tung sah Institute of Micro-Nano science and Technology Xiamen UniversityXiamen361102China

The earthworm has been attracted much attention in the research and development of biomimetic robots due to their unique locomotion mechanism,compact structure,and small motion *** paper presents a new design and prototype of a worm-inspired metameric robot with a movement pattern similar to that of *** robot consists of multiple telescopic modules connected in series through joint *** telescopic module mimics the contraction and elongation motion modes of the earthworm segments.A kinematic and dynamic analysis is conducted on the telescopic module,and an input torque calculation method is provided to ensure sufficient friction between the robot and the pipe *** gait modes of the prototype robot for straight and turning locomotion are introduced,and these modes are extended to robots constructed by different numbers of telescopic *** addition,a method is proposed to increase the friction between the robot and the pipe wall in the aforementioned gait modes without changing the robot structure,thereby improving the robot’s motion ability in *** theoretical model of gait modes has also been validated through gait *** findings of this paper would provide a useful basis for the design,modeling,and control of future worm inspired robots.

关键词： Bio-inspired robot spatial linkage mechanism Kinematics model Peristaltic locomotion

Generic Existence of Infinitely Many Non-contractible Closed Geodesics on Compact space Forms

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Acta Mathematica sinica,English series 2024年第7期40卷 1674-1684页

作者： Hui Liu yu chen Wang school of Mathematics and statistics Wuhan UniversityWuhan430072P.R.China school of Mathematics Tianjin Normal UniversityTianjin300384P.R.China

Let M=s^(n)/Γand h be a nontrivial element of finite order p inπ_(1)(Μ),where the integers n,p≥2,Γis a finite abelian group which acts freely and isometrically on the n-sphere and therefore M is diffeomorphic to a compact space *** this paper,we prove that there are infinitely many non-contractible closed geodesics of class[h]on the compact space form with C^(r)-generic Finsler metrics,where 4≤r≤∞.The conclusion also holds for Cr-generic Riemannian metrics for 2≤r≤∞.The proof is based on the resonance identity of non-contractible closed geodesics on compact space forms.

关键词： Compact space forms non-contractible closed geodesics generic Finsler metrics resonance identity

Progress on Bionic Textured Cutting Tools:A Review and Prospects

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Journal of Bionic Engineering 2024年第1期21卷 19-55页

作者： Hong Wei Guangjun chen Zhuang chen Zhiwei yu Jias.uai Huang Tianjin Key Laboratory of High speed Cutting and Precision Processing Tianjin 300222China school of Mechanical Engineering Tianjin University of Technology and EducationTianjin 300222China

Cutting tools are known as the“productivity”of the manufacturing industry,which affects the production efficiency and quality of the workpiece,and has become the focus of research and attention in academia and ***,traditional cutting tools often suffer from adhesion or wear during the cutting process,which considerably reduces the cutting efficiency and service life of the tools,and makes it difficult to meet current production *** solve the above problems,scholars have introduced bionics into the tool’s design,applying the microscopic structure of the biological surface to the tool surface to alleviate the tool’s *** paper mainly summarizes the research progress of bionic textured cutting ***,categorize whether the bionic texture design is inspired by a single organism or multiple ***,it is dis.ussed that the non-smooth surface of the biological surface has five characteristics:hydrophilic lubricity,wear resistance,drag reduction and hydrophobicity,anti-adhesion,and arrangement,and the non-smooth structure of these different characteristics are applied to the surface of the tool is designed with bionic ***,the cutting performance of bionic textured cutting tools is *** anti-friction and wear-resisting mechanism of bionic textured cutting tools is ***,some pending problems and perspectives have been proposed to provide new inspirations for the design of bionic textured cutting tools.

关键词： Bionic textured cutting tools Biological microstructure characteristics Cutting performance Anti-friction and wear-resisting mechanism

Enhancing visible-light-driven NO oxidation through molecular‐level insights of dye-loaded sea sands

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Rare Metals 2024年第2期43卷 543-554页

作者： yu-Han Li Bang-Fu chen sónia A.C.Carabineiro You-yu Duan Ping Tan Wing-Kei Ho Fan Dong Engineering Research Center for Waste Oil Recovery Technology and Equipment Ministry of EducationChongqing Key Laboratory of Catalysis and New Environmental MaterialsChongqing Technology and Business UniversityChongqing400067China Nanchang Institute of Technology Nanchang33044China LAQV-REQuIMTE Department of ChemistryNOVA School of Science and TechnologyUniversidade NOVA de Lisboa2829-516CaparicaPortugal College of Physics and Center of Quantum Materials and Devices Chongqing UniversityChongqing401331China Department of science and Environmental s.udies The Education University of Hong KongHong Kong999077China

Natural minerals,abundant and easily obtained through simple physical processing,offer a cost-effective and environmentally friendly solution for dyeing wastewater disposal and air pollution *** s.udy investigates the photocatalytic removal of NO using natural different types of dyes,loaded on natural sand,under visible light *** examining various coating concentrations of dyes and sand weights,we discovered that sand loaded with Rhodamine B(RhB)exhibits high activity for the photo-oxidation of NO.A combination results of X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPs),Fourier transform infrared spectroscopy(FTIR)and thermogravimetric(TG)analyses confirm the presence of siO_(2),CaCO_(3),Al_(2)O_(3)and iron oxides as the main components of the ***,s.udying RhB-loaded individual components reveals that CaCO_(3)plays a crucial role in enhancing the NO removal *** results and theoretical calculations demonstrate the establishment of a directional charge transfer channel from CaCO_(3)to RhB,facilitating the adsorption and activation of molecular NO and O_(2).This work not only promotes the utilization of natural mineral res.urces but also enriches the fields of environmental photochemistry and semiconductor photocatalysis.

关键词： sand dyes Rhodamine B Photo-oxidation of NO Visible light illumination

Quantum spin Exchange Interactions to Accelerate the Redox Kinetics in Li–s Batteries

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Nano-Micro Letters 2024年第5期16卷 370-383页

作者： yu Du Weijie chen yu Wang yue yu Kai Guo Gan Qu Jianan Zhang Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation of Zhengzhou City College of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001People’s Republic of China

spin-engineering with electrocatalysts have been exploited to suppress the“s.uttle effect”in Li–s *** selec-tion,spin-dependent electron mobility and spin potentials in activation barriers can be optimized as quantum spin exchange interactions lead-ing to a significant reduction of the electronic repulsions in the orbitals of ***,we anchor the MgPc molecules on fluorinated carbon nanotubes(MgPc@FCNT),which exhibits the single active Mg sites with axial *** to the density functional theory calculations,the electronic spin polarization in MgPc@FCNT not only increases the adsorption energy toward LiPss intermediates but also facilitates the tunneling process of electron in Li–s *** a result,the MgPc@FCNT provides an initial capacity of 6.1 mAh cm^(-2) even when the high sulfur loading is 4.5 mg cm^(-2),and still maintains 5.1 mAh cm^(-2) after 100 *** work provides a new perspective to extend the main group single-atom catalysts enabling high-performance Li–s batteries.

关键词： Metal phthalocyanines spin polarization Electrocatalysis Li–s batteries

A resonant high-pres.ure microsensor based on a composite pres.ure-sensitive mechanism of diaphragm bending and volume compression

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Microsystems & Nanoengineering 2024年第2期10卷 57-66页

作者： Pan Qian Zongze yu Jie yu yulan Lu Bo Xie Jian chen Deyong chen Junbo Wang The state Key Laboratory of Trans.ucer Technology Aerospace Information Research InstituteChinese Academy of SciencesBeijing100190China The school of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing100049China

In this paper,a composite pres.ure-sensitive mechanism combining diaphragm bending and volume compression was developed for resonant pres.ure microsensors to achieve high-pres.ure measurements with excellent *** composite mechanism was explained,and the sensor structure was designed based on theoretical analysis and finite element *** all-silicon resonant high-pres.ure microsensor with multiple miniaturized cavities and dual resonators was developed,where dual resonators positioned in two resonant cavities with suitably different widths are used to perform opposite characteristics in pres.ure and the same characteristics at different temperatures,which can improve pres.ure sensitivities and realize temperature self-compensation by differential frequency *** microsensor was fabricated by microfabrication,and the experimental results showed that the sensor had an accuracy of±0.015%full scale(Fs)in a pres.ure range of 0.1~100 MPa and a temperature range of−10~50℃.The pres.ure sensitivity of the differential frequency was 261.10 Hz/MPa(~2523 ppm/MPa)at a temperature of 20℃,and the temperature sensitivities of the dual resonators were−1.54 Hz/℃(~−14.5 ppm/℃)and−1.57 Hz/℃(~−15.6 ppm/℃)at a pres.ure of 2 *** differential output had an outstanding stability within±0.02 Hz under constant temperature and ***,this research provides a convenient solution for high-pres.ure measurements because of its advantages,namely,large range,excellent accuracy and stability.

关键词： stability resonant bending

A novel domain decomposition-based model for efficient dynamic predictions of large composite machine tools

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science China(Technological sciences) 2024年第6期67卷 1765-1782页

作者： yu YangBo JI yu Lei chen YanRen Xu Kun BI QingZhen state Key Laboratory of Mechanical system and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China

We propose a large combined moving component composed of carbon fiber reinforced polymer(CFRP)laminates for making lightweight machine tools with high dynamic *** accurate dynamic prediction of composite machine tools is essential for the new generation machine *** paper aims to address two challenges in numerical dynamic modeling and the design of composite machine tools to enhance development efficiency.(1)Anisotropic composite laminates,which form the composite machine tool,exhibit coupling in various *** propose the generalized continuity condition of the boundary to tackle this dynamic modeling challenge.(2)Composite machine tools feature numerous composite-metal coupled *** mechanical model correction of isotropic metals is performed to address their *** take the example of a five-axis gantry machine tool with composite moving parts,establish a dynamic model for efficient prediction,and verify it through simulation and *** proposed method yields remarkable results,with an average relative error of only 3.85%in modal frequency prediction and a staggering 99.7%reduction in solution time compared to finite element *** further dis.uss the dynamic performance of the machine tool under varied stacking angles and layer numbers of the composite machine *** propose general design criteria for composite machine tools to consider the modal frequency and manufacturing cost of machine tools.

关键词： machine tool dynamics carbon fiber reinforced polymer composite laminates