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Bio-inspired Design and Inverse Kinematics Solution of an Omnidirectional Humanoid Robotic Arm with Geometric and Load Capacity Constraints

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Journal of Bionic Engineering 2024年第2期21卷 778-802页

作者： Zhichao Zhu Zirong luo Yiming Zhu tao Jiang Minghai Xia Shanjun Chen Boyu jin College of Intelligence Science and Technology National University of Defense TechnologyChangshaChina

Inspired by the driving muscles of the human arm,a 4-Degree of Freedom(DOF)concentrated driving humanoid robotic arm is proposed based on a spatial double parallel four-bar *** four-bar mechanism design reduces the inertia of the elbow-driving unit and the torque by 76.65%and 57.81%,*** the human pose regulation strategy that the human arm picks up a heavy object by adjusting its posture naturally without complicated control,the robotic arm features an integrated position-level closed-form inverse solution method considering both geometric and load capacity *** method consists of a geometric constraint model incorporating the arm angle(φ)and the Global Configuration(GC)to avoid joint limits and singularities,and a load capacity model to constrain the feasible domain of the arm ***,trajectory tracking simulations and experiments are conducted to validate the feasibility of the proposed inverse solution *** simulated maximum output torque,maximum output power and total energy consumption of the robotic arm are reduced by up to 2.0%,13.3%,and 33.3%,*** experimental results demonstrate that the robotic arm can bear heavy loads in a human-like posture,effectively reducing the maximum output torque and energy consumption of the robotic arm by 1.83%and 5.03%,respectively,while avoiding joints beyond geometric and load capacity *** proposed design provides a high payload–weight ratio and an efficient pose control solution for robotic arms,which can potentially broaden the application spectrum of humanoid robots.

关键词： Humanoid robotic arm Bio-inspired design Inverse kinematics solution Load capacity constraint Geometric constraint

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Holder continuous weak solutions of the 2D Boussinesq equation with thermal diffusion

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Science China Mathematics 2024年第8期67卷 1777-1806页

作者： Tianwen luo tao tao Liqun Zhang Yau Mathematical Sciences Center Tsinghua UniversityBeijing 100084China School of Mathematics Shandong UniversityJinan 250100China Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

We show the existence of Holder continuous periodic weak solutions of the 2D Boussinesq equation with thermal diffusion which satisfy the prescribed kinetic *** precisely,for any smooth e(t):[0,1]→R+andε∈(0,110),there exist v∈C 110−ε([0,1]×T2)andθ∈C 1,120−εt 2 C 2,1 x 10−ε([0,1]×T2),which satisfy(1.1)in the sense of distribution and e(t)=ˆT2|v(t,x)|2 dx,∀t∈[0,1].

关键词： 2D Boussinesq equation with thermal diffusion Holder continuous periodic weak solutions prescribed kinetic energy

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TOFD detection of shallow subsurface defects in aluminum alloy thin plates by half-skip mode-converted wave

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Chinese Journal of Aeronautics 2024年第6期37卷 454-463页

作者： Shijie jin Zhicheng WANG Zhongbing luo NDT&E Laboratory Dalian University of TechnologyDalian 116085China

Aluminum alloy is widely applied to the aerospace ***,the inspection of thin plates using Time-of-Flight Diffraction(TOFD)technique is restricted by the near-surface dead zone because of the coupling between diffracted longitudinal wave and lateral *** halfskip mode-converted wave is introduced to decrease dead zone and detect defects in aluminum alloy thin plates by increasing ray path and propagation *** quantitative correlation for the diffracted shear wave from longitudinal back-wall wave is deduced in combination with the acoustic path,realizing the accurate location of shallow subsurface *** and experimental results indicate that the dead zone is decreased by 38% by the half-skip mode-converted wave,and the location errors are within 5% for the aluminum alloy plate with a thickness of 7.0 *** to other alternative TOFD techniques,half-skip mode-converted wave has better response amplitude and positioning accuracy,demonstrating strong applicability in TOFD inspection of thin plates.

关键词： Ultrasonic testing Time-of-Flight Diffraction(TOFD) Dead zone Half-skip mode-converted wave Quantitative detection

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Effect of short-time low-temperature austenitizing on microstructure and mechanical properties of DT300 ultra-high strength steel fabricated by laser powder bed fusion

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Journal of Iron and Steel Research(International) 2024年第7期31卷 1763-1777页

作者： Chen-yang Jiang Xiao-qiang Li jin-tao Wang Hao luo Sheng-qing Gao Sheng-guan Qu Chao Yang National Engineering Research Centre of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640GuangdongChina Institute of New Materials Guangdong Academy of ScienceGuangzhou 510650GuangdongChina

To address the inhomogeneous microstructure and improve the mechanical properties of DT300 ultra-high strength steel specimens fabricated by laser powder bed fusion,different post-heat treatment schedules are *** the increase in austenitizing temperature and time,the migration rate of austenite grain boundaries continuously increases with the dissolution of nano-carbides,and the formation of nano-oxides and twin martensite is also inhibited *** rapid growth in the size of prior austenite grains and martensite laths,as well as the decrease in the content of nano-oxides and twin martensite,led to a rapid decrease in the strength(yield strength and ultimate tensile strength)from HT2 to HTF *** HT1 specimens(austenitizing at 830℃for 30 min,then oil quenching and tempering at 300℃for 120 min and finally air cooling)display excellent mechanical properties of yield strength of 1572 MPa,ultimate tensile strength of 1847 MPa,elongation of 9.84%,and fracture toughness of 106 MPa m^(1/2),which are counterparts to those of conventional DT300 steel forgings after heat treatment.

关键词： DT300 ultra-high strength steel Laser powder bed fusion-Short-time low-temperature austenitizing Microstructure Mechanical property

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Feedback linearization and equivalent-disturbance compensation control strategy for piezoelectric stage

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Nanotechnology and Precision Engineering 2024年第2期7卷 49-59页

作者： tao Huang Yingbin Wang Zhihong luo Huajun Cao Guibao tao Mingxiang Ling State Key Laboratory of Mechanical Transmissions for Advanced Equipment Chongqing UniversityChongqing 400044China College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China Hongdu Aviation Industry Group NanchangJiangxi 330000China Robotics and Microsystems Center Soochow UniversitySuzhou 215123China

Piezoelectric stages use piezoelectric actuators and flexure hinges as driving and amplifying mechanisms,*** systems have high positioning accuracy and high-frequency responses,and they are widely used in various precision/ultra-precision positioning ***,the main challenge with these devices is the inherent hysteresis nonlinearity of piezoelectric actuators,which seriously affects the tracking accuracy of a piezoelectric *** by this challenge,in this work,we developed a Hammerstein model to describe the hysteresis nonlinearity of a piezoelectric *** particular,in our proposed scheme,a feedback-linearization algorithm is used to eliminate the static hysteresis *** addition,a composite controller based on equivalent-disturbance compensation was designed to counteract model uncertainties and external *** analysis of the stability of a closed-loop system based on this feedback-linearization algorithm and composite controller was performed,and this was followed by extensive comparative experiments using a piezoelectric stage developed in the *** experimental results confirmed that the feedback-linearization algorithm and the composite controller offer improved linearization and trajectory-tracking performance.

关键词： Piezoelectric stage Hysteresis nonlinearity Feedback linearization Equivalent-disturbance compensation

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Causal temporal graph attention network for fault diagnosis of chemical processes

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Chinese Journal of Chemical Engineering 2024年第6期70卷 20-32页

作者： Jiaojiao luo Zhehao jin Heping jin Qian Li Xu Ji Yiyang Dai School of Chemical Engineering Sichuan UniversityChengdu 610065China China Three Gorges Corporation Beijing 100038China

Fault detection and diagnosis(FDD)plays a significant role in ensuring the safety and stability of chemical *** the development of artificial intelligence(AI)and big data technologies,data-driven approaches with excellent performance are widely used for FDD in chemical ***,improved predictive accuracy has often been achieved through increased model complexity,which turns models into black-box methods and causes uncertainty regarding their *** this study,a causal temporal graph attention network(CTGAN)is proposed for fault diagnosis of chemical processes.A chemical causal graph is built by causal inference to represent the propagation path of *** attention mechanism and chemical causal graph were combined to help us notice the key variables relating to fault *** in the Tennessee Eastman(TE)process and the green ammonia(GA)process showed that CTGAN achieved high performance and good explainability.

关键词： Chemical processes Safety Fault diagnosis Causal discovery Attention mechanism Explainability

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Increasing operational stability of journal bearing in hydraulic suspension micro-pump by herringbone grooved structure

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Science China(Technological Sciences) 2024年第3期67卷 853-862页

作者： HONG tao XING GuanYing ZUO HuaiYu XUE Song luo XiaoBing State Key Laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The operational stability of radial journal bearings is the bottleneck that limits the reliability of hydraulic suspension micropump. Due to self-excited vibrations, the whirl amplitude of the plain journal bearing(PJB) is large at high rotational speeds,which will accelerate wear failure. It has been proven that employing herringbone grooved journal bearing(HGJB) is an effective method to reduce the whirl amplitude and improve operational stability. However, enhancing the stability of journal bearings in micro-pumps by herringbone grooved structures has rarely been studied, and its effect needs to be verified. We validated the mechanism of the stability improvement with the CFD method and compared the dynamic characteristics of HGJB and PJB by rotor dynamics evaluation and experiment. The experimental results show that under the same conditions the whirl amplitude of the HGJB decreases by 29.61% in the x direction and by 24.09% in the y direction compared with that of the PJB. This study reveals the effect of the herringbone grooved structure on the operational stability of bearings and may provide guidance for the reliability improvement of hydraulic suspension micro-pump.

关键词： journal bearing herringbone groove hydrodynamic effect micro-pump

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A combined experimental and DEM investigation of grain interlocking in sheared granular assemblies

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Particuology 2024年第7期90卷 436-451页

作者： Rui Lu Qiang luo Tengfei Wang David P.Connolly tao Xie School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of High-Speed Railway Engineering(Southwest Jiaotong University) Ministry of EducationChengdu 610031China School of Civil Engineering University of LeedsLeeds LS29JTUK Department of Civil Engineering McMaster UniversityHamiltonONCanada

Compacted granular material,integral to geotechnical engineering,undergoes translation,rotation,and interlocking when subject to shear displacements or external *** present study focuses on the interlocking of heterogeneous granular materials,a complex behavior influenced by gradation,compaction,and varying particle geometry,and has consequently received limited attention in existing *** address this research gap,we conducted an analysis on the effect of grain interlocking on the shear resistance of granular assemblies,using a combination of laboratory testing and the discrete element method(DEM).Initially,large-scale direct shear tests were conducted on gravel−sand mixes with varying degrees of compaction and normal *** of the mixes also underwent subsequent shear reversal to explore the differences in grain interlocking between the two shearing processes on the shear *** analyzing the laboratory results,a mesoscopic scale investigation was performed by replicating the test using discrete element *** facilitate this,granular particle geometries were measured using 3D laser scanning based on the physical lab ***,based on these scans,discrete element R-block and ball models were utilized to construct both the coarse and fine particles within the *** vibro-compaction was employed to regulate the degree of *** results indicate that an increase in vertical pressure,coupled with a zero dilatancy angle,results in a rising stress ratio,indicative of grain *** interlocking exhibits a positive correlation with both the coarse content and the degree of compaction,and varies depending on the shear *** interlocking progresses,the shear band,induced by particle movement,expands and is associated with reduced particle rotation near the shear *** study further reveals a consistent positive correlation between interlocking and the principal orientation angle of strong normal c

关键词： Granular material Interlocking Shear resistance Direct shear Discrete element method Vibro-compaction

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A universal and ultrafast method for fabricating a library of nanocellulose-supported metal nanoparticles

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Progress in Natural Science:Materials International 2024年第2期34卷 389-395页

作者： Ziyi luo Xiaoyang Wang Baihua Cui Hao luo tao Zhang Jia Ding Yanan Chen Yida Deng Wenbin Hu School of Materials Science and Engineering Tianjin University Department of Chemistry National University of Singapore State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and Engineering Hainan University

Using nanocatalysts to catalyze water electrolysis for hydrogen production is an ideal solution to address the energy *** most well-adopted fabrication methods for nanocatalysts are tube furnace annealing,Hydrothermal method,etc.,hardly satisfying the trade-off among coarsening,dispersity,and particle size due to mutual ***,a universal,ultrafast and facile cellulose nanometer whiskers-high temperature shock（CNWHTS） method was reported for fabricating a library of ultrafine metal nanoparticles with uniform dispersion and narrow size *** metal-anchor functional groups in CNW（i.e.,-OH and-COOH） and the characteristics of the HTS method for ultrafast heating and powerful quenching synergistically contribute to the successful synthesis of metal *** an initial demonstration,the as-prepared Pt nanocatalyst(η10 mA cm-2=51.8 mV) shows more excellent catalytic hydrogen evolution reaction（HER） performance than the Pt catalyst prepared in the tubular furnace(η10 mA cm-2=169.4 mV).This rapid and universal CNW-HTS method can pave the way for nanomanufacturing to produce high-quality metal nanoparticles,thereby expanding applications of energy conversion and electrocatalysis.

关键词： Electrocatalysis High-temperature shock Hydrogen evolution reaction (HER) Nanocellulose Nanomanufacturing Nanoparticles

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Analysis of the causes of primary revision after unicompartmental knee arthroplasty: A case series

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World Journal of Clinical Cases 2024年第9期12卷 1560-1568页

作者： jin-Long Zhao Xiao jin He-tao Huang Wei-Yi Yang Jia-Hui Li Ming-Hui luo Jun Liu Jian-Ke Pan The Second Clinical Medical College Guangzhou University of Chinese MedicineGuangzhou 510405Guangdong ProvinceChina Department of Chinese Medicine The First Affiliated HospitalJinan UniversityGuangzhou 510630Guangdong ProvinceChina The Second School of Clinical Medical Sciences Guangzhou University of Chinese MedicineGuangdong Academy of Traditional Chinese MedicineGuangzhou 510405Guangdong ProvinceChina The Second Affiliated Hospital Guangzhou University of Chinese Medicine(Guangdong Provincial Hospital of Chinese Medicine)Guangzhou 510120Guangdong ProvinceChina The Affiliated TCM Hospital Guangzhou Medical UniversityGuangzhou 510405Guangdong ProvinceChina The Research Team on Bone and Joint Degeneration and Injury Guangdong Provincial Academy of Chinese Medical SciencesGuangzhou 510405Guangdong ProvinceChina

BACKGROUND Unicompartmental knee arthroplasty(UKA)has great advantages in the treatment of unicompartmental knee osteoarthritis,but its revision rate is higher than that of total knee *** To summarize and analyse the causes of revision after *** This is a retrospective case series study in which the reasons for the first revision after UKA are *** analysed the clinical symptoms,medical histories,laboratory test results,imaging examination results and treatment processes of the patients who underwent revision and summarized the reasons for primary revision after *** A total of 13 patients,including 3 males and 10 females,underwent revision surgery after *** average age of the included patients was 67.62 *** prosthesis was used for 3 d to 72 *** main reasons for revision after UKA were improper suturing of the surgical opening(1 patient),osteophytes(2 patients),intra-articular loose bodies(2 patients),tibial prosthesis loosening(2 patients),rheumatoid arthritis(1 patient),gasket dislocation(3 patients),anterior cruciate ligament injury(1 patient),and medial collateral ligament injury with residual bone cement(1 patient).CONCLUSION The causes of primary revision after UKA were gasket dislocation,osteophytes,intra-articular loose bodies and tibial prosthesis *** of these factors may greatly reduce the rate of revision after UKA,improve patient satisfaction and reduce medical burden.

关键词： Unicompartmental knee arthroplasty Total knee arthroplasty Causes Revision Case series

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