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Chinese Journal of Aeronautics 2024年第10期37卷 471-482页

作者： Yingke YANG Dongsheng LI Yunong ZHAI Jie WANG Lei XUE Zhiyong YANG School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Ningbo Institute of Technology Beihang UniversityNingbo 3158002China COMAC Shanghai Aircraft manufacturing Co. Ltd.Shanghai 201324China

Robots are finding increasing application in aircraft composite structure assembly due to their flexibility and the growing demand of aircraft manufacturers for high production *** contact force of the composite frame in a robotic assembly of the aircraft composite fuselage panel can hardly be controlled due to the multi-surface variable contact stiffness caused by compliance and complex shape with multiple mating *** paper proposes a robotic assembly system for the aircraft composite fuselage frame with a compliant contact force control strategy using the Gaussian process surrogate ***,a robotic assembly system is introduced,and the global coordinate system transformation model is ***,a compliant force control architecture is designed to generate the desired output ***,a Gaussian process surrogate model with uncertainties is utilized to model the complicated relationship between the robot’s output force and the normal contact force acting on the mating surface of the composite ***,an optimal contact force control strategy is implemented to improve the contact ***,an experiment demonstrates that the proposed methodology can ensure that the contact force on each surface is within the limit of the engineering specification and uniformly distributed,improving the quality compared to the traditional assembly process.

关键词： Aircraft Composite structure assembly Multi-surface contact Compliant control Gaussian process Uncertainty

Multi-Material Topology Optimization for Spatial-Varying Porous Structures

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工程与科学中的计算机建模(英文) 2024年第1期138卷 369-390页

作者： Chengwan Zhang Kai Long Zhuo Chen Xiaoyu Yang Feiyu Lu Jinhua Zhang Zunyi Duan State Key Laboratory for Alternate Electrical Power system with Renewable Energy Sources North China Electric Power UniversityBeijing102206China School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou510640China Faculty of Materials and manufacturing Beijing University of TechnologyBeijing100124China Institute of Structural Health Monitoring and Control School of MechanicsCivil Engineering&ArchitectureNorthwestern Polytechnical UniversityXi’an710072China

This paper aims to propose a topology optimization method on generating porous structures comprising multiple *** mathematical optimization formulation is established under the constraints of individual volume fraction of constituent phase or total mass,as well as the local volume fraction of all *** original optimization problem with numerous constraints is converted into a box-constrained optimization problem by incorporating all constraints to the augmented Lagrangian function,avoiding the parameter dependence in the conventional aggregation ***,the local volume percentage can be precisely *** effects including the globalmass bound,the influence radius and local volume percentage on final designs are exploited through numerical *** numerical results also reveal that porous structures keep a balance between the bulk design and periodic design in terms of the resulting *** results,including those for irregular structures andmultiple volume fraction constraints,demonstrate that the proposedmethod can provide an efficient solution for multiple material infill structures.

关键词： Topology optimization porous structures local volume fraction augmented lagrangian multiple materials

Interactive mechanism and friction modelling of transient tribological phenomena in metal forming processes: A review

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Friction 2024年第3期12卷 375-395页

作者： Xiao YANG Heli LIU Lemeng ZHANG Yiran HU Denis J.POLITIS Mohammad M.GHARBI Liliang WANG Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK Department of Mechanical and manufacturing Engineering University of CyprusNicosia 1678Cyprus Quaker Houghton Deutschland GmbH Dortmund 44319Germany

The accurate representation of tribological boundary conditions at the tool–workpiece interface is crucial for analysis and optimization of formability,material flow,and surface quality of components during metal forming *** has been found that these tribological conditions vary spatially and historically with process parameters and contact *** time-dependent tribological behaviours are also known as transient tribological phenomena,which are widely observed during forming processes and many other manufacturing application ***,constant friction values are usually assigned to represent complex and dynamic interfacial conditions,which would introduce deviations in the relevant *** this paper,transient tribological phenomena and the contemporary understanding of the interaction between friction and wear are reviewed,and it has been found that these phenomena are induced by the transitions of friction mechanisms and highly dependent on complex loading conditions at the *** modelling techniques for transient behaviours for metal forming applications are also *** accurately describe the evolutionary friction values and corresponding wear during forming,the advanced interactive friction modelling has been established for different application scenarios,including lubricated condition,dry sliding condition(metal-on-metal contact),and coated system.

关键词： transient tribological phenomena interactive friction mechanism modelling techniques metal forming

Neutral color and self-healable electrochromic system based on CuI/Cu and I_(3)^(-)/I^(-)conversions

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Nano Research 2024年第5期17卷 4437-4443页

作者： Junsen Zhong Bingkun Huang Kunjie Yang Zuju Ma Lingyu Du Ning Luo Fengjiao Tang Chuanxin Hou Fuyi Jiang Litao Kang College of Environment and Materials Engineering Yantai UniversityYantai 264005China School of Energy and Power Engineering Shandong UniversityJinan 250061China Shandong Laboratory of Advanced Materials and Green manufacturing(Yantai) Yantai 264001China

The electrochromic(EC)mechanisms of inorganic materials are usually based on reversible cation insertion/extraction or metal deposition/dissolution,which are plagued by ion trapping and dendrite growth,*** this paper,a novel conversion-type electrochromic mechanism is proposed,by making good use of the CuI/Cu redox *** CuI-based electrochromic system shows a neutral color switching from transparent and dim *** simply increasing the bleaching voltage,I_(3)^(-)/I^(-)redox couple can be further *** generated I_(3)^(-)will readily react with Cu,effectively improving the conversion reversibility and thereby rejuvenating the degraded electrochromic *** to the well-designed electrode and the self-healing ability,this conversion electrochromic system achieves rapid response times(tcoloring:23 s,tbleaching:6 s),decant optical modulation amplitude(26.4%),high coloration efficiency(86.15 cm^(2)·C^(-1)),admirable cyclic durability(without performance degradation after 480 cycles)and excellent optical memory ability(transmittance variation<1%after 10 h open-circuit storage).The establishment of this conversion-type electrochromism may inspire the exploration of novel electrochromic materials and devices.

关键词： electrochromic CuI conversion reaction self-healing neutral color

Effect of Preload Force on Heat Generation of Li(Ni_(0.8)Co_(0.1)Mn_(0.1))O_(2)/SiO_(x)-C system Batteries:The Discharge Process

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Journal of Thermal Science 2024年第5期33卷 1809-1825页

作者： LIN Chunjing LAI Zhenxing BAI Guangli MA Biao WEI Zhen QI Chuang LIU Shiqiang Key Laboratory of Advanced manufacturing Technology for Automobile Parts Ministry of EducationChongqing University of TechnologyChongqing 400054China China Auto Research New Energy Vehicle Inspection Center(Tianjin)Co Tianjin 300300China

Lithium-ion batteries(LIBs)undergo various degradation phenomena such as material decomposition,structural change and uneven lithium ion distribution during long-term cycles,which would affect their performance and *** order to improve the performance of the LIBs during their life cycle,preload force is preset when the batteries are *** preload forces will in turn affect the cycle life and heat generation of the *** order to address this issue,this work carries out charge/discharge cycle tests on a NCM811 battery under different preload *** calorimetry tests are performed to investigate the battery heat generation under different states of health(SOHs)and preload *** on the test results,an empirical prediction model for heat generation power as a function of SOH is *** show that when the preload force is 5 N·m,the battery capacity decreases in the slowest rate and the average heat generation power is the *** in peaks of the incremental capacity curve can be used to characterize the loss of lithium at the electrode,which in turn characterizes the change of heat generation power of the *** average heat generation power is mainly affected by the SOH,going through a period of trough with the decrease of the SOH and continuing to increase after crossing the critical *** general,these findings emphasize the relationship between preload force,SOH and heat generation power,which is helpful for the judgment of optimal preload to improve the efficiency of LIBs.

关键词： lithium ion battery cyclic aging preload force heat generation characteristic

Anomalous{1012}tensile twinning and subsequent detwinning in a friction stir processed carbon fiber-reinforced Mg composite

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Journal of Magnesium and Alloys 2024年第4期12卷 1511-1517页

作者： Wei Zhao Zhihao Jiang Xiang Wu Yujing Liu Haokun Yang Jun Wang Qi Liu Xiaochun Liu Institute of Metals College of Materials Science and EngineeringChangsha University of Science&TechnologyChangsha 410114China Department of Mechanical Engineering City University of Hong KongHong KongChina Smart manufacturing division Hong Kong Productivity CouncilHong Kong SAR 999077China Institute for Frontier Materials Deakin UniversityGeelongVIC 3216Australia Department of Industrial and systems Engineering The Hong Kong Polytechnic UniversityHong KongChina

*** text Owing to their low density and high specific strength,magnesium alloys and magnesium-based composites have great potential as structure metal materials in applications where lightweight matters[1–4].Deformation twins[5],especially the{1012}tension twins(also called tensile or extension twins)with a low critical resolved shear stress(CRSS)[6],are commonly observed in Mg *** can provide the much-needed deformation along the c-axis in their hcp structure resulting from the very few easily activated slip systems in this crystal structure[7].The tensile twinning activation usually follows the macroscopic Schmid factor law[2],i.e.,the twin variant with the highest Schmid factor occurs,and it only appears when its Schmid factor is positive.

关键词： friction deformation magnesium

Data-driven Anomaly Detection Method Based on Similarities of Multiple Wind Turbines

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Journal of Modern Power systems and Clean Energy 2024年第3期12卷 803-818页

作者： Xiangjun Zeng Ming Yang Chen Feng Mingqiang Wang Lingqin Xia the College of Electrical Engineering&New Energy China Three Gorges UniversityYichang 443002China the Key Laboratory of Power system Intelligent Dispatch and Control Shandong UniversityJinan 250061China

The operating conditions of wind turbines(WTs)in the same wind farm(WF)may share similarities due to their shared manufacturing process,control strategy,and operating ***,the similarities of WTs are seldom considered in WT anomaly detection,resulting in the disregard of useful *** paper proposes a method to improve the reliability and accuracy of WT anomaly detection using the supervisory control and data acquisition(SCADA)data of multiple WTs in the same ***,a similarity assessment method based on a comparison of different observation time series is proposed,which objectively quantifies the similarities of WT operating ***,the SCADA data of the target WT and selected WTs that are similar are used to establish several estimation models through a long short-term memory(LSTM)*** models that exhibit good estimation performance are used to construct a combined estimation model that estimates the variations in the monitored variables of the target ***,an anomaly detection method that jointly compares the effective value and information entropy of the residuals is proposed to identify *** effectiveness and accuracy of the proposed method are verified using the data of two actual WFs.

关键词： Anomaly detection information entropy long short-term memory similarity assessment wind farm wind turbines

Clinical and socioeconomic determinants of survival in biliary tract adenocarcinomas

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1374-1383页

作者： Laura Sahyoun Kay Chen Cynthia Tsay George Chen Petr Protiva Department of Gastroenterology and Hepatology Weill Cornell MedicineNew YorkNY 10065United States Gastroenterology Section Jennifer Moreno VA San Diego Healthcare SystemSan DiegoCA 92161United States division of Gastroenterology Department of MedicineUniversity of California San DiegoLa JollaCA 92093United States Department of Gastroenterology and Hepatology John Hopkins HospitalBaltimoreMD 21287United States Department of Digestive Diseases Yale New Haven HospitalNew HavenCT 06520United States Department of Gastroenterology VA Connecticut Health Care SystemWest HavenCT 06516United States

BACKGROUND Despite advances in detection and treatments,biliary tract cancers continue to have poor survival ***,there is limited data investigating the significance of socioeconomic status,race/ethnicity,and environmental factors in biliary tract cancer *** from the Surveillance,Epidemiology,and End Results database for biliary and gallbladder adenocarcinomas were extracted from 1975 to ***-conomic data included smoking,poverty level,education,adjusted household income,and percentage of foreign-born persons and urban *** was calculated with Cox proportional hazards models for death in the 5-year period following *** Our study included 15883 gallbladder,11466 intrahepatic biliary,12869 extrahepatic biliary and 7268 ampulla of Vater adenocarcinoma *** analyzing county-specific demographics,patients from counties with higher incomes were associated with higher survival rates[hazard ratio(HR)=0.97,P<0.05].Similarly,counties with a higher percentage of patients with a college level education and counties with a higher urban population had higher 5-year survival rates(HR=0.96,P=0.002 and HR=0.97,P=0.004,respectively).CONCLUSION Worse survival outcomes were observed in lower income counties while higher income and education level were associated with higher 5-year overall survival among gallbladder and biliary malignancies.

关键词： Biliary tract cancers Survival Outcomes research Socioeconomic factors Healthcare disparities

Impact of vaccination on the dynamics of COVID-19:A mathematical study using fractional derivatives

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International Journal of Biomathematics 2024年第2期17卷 201-232页

作者： Shraddha Ramdas Bandekar Mini Ghosh C.Rajivganthi division of Mathematics School of Advanced Sciences Vellore Institute of TechnologyChennaiIndia

Arrival of a new disease marks a yearlong destruction of human lives and economy in general,and if the disease turns out to be a pandemic the loss is ***-19 is one such pandemic that has claimed millions of lives till *** is a suffering throughout the world due to various factors associated with the pandemic,be it loss of livelihoods because of sudden shutdown of companies and lockdown,or loss of lives due to lack of medical aid and inadequate vaccination *** this study,we develop a six-compartmental epidemiological model incorporating *** motivation behind the study is to analyze the significance of higher vaccination efficacy and higher rate of population getting vaccinated in controlling the rise in infectives and thereby the untimely demise of various *** work begins with an ordinary differential equation model followed by stability analysis of the same,after which a fractional-order derivative model of the same is formulated and the existence of uniformly stable solution for the system is *** addition to this,we present the stability of the equilibria in general for the fractional model *** sensitivity analysis of the basic reproduction number along with its correlation with various parameters is *** addition to this,sensitivity of certain state variables in the fractional model with respect to *** orders as well with respect to different infection rate is exhibited in this *** related to lockdown and usage of face shields are incorporated in the entire study,and importance of these is highlighted in the study as *** major takeaway from the study is that mere vaccination will not sufice in eradication of the *** vaccine efficacy plays a major role along with other intervention included in the *** numerical simulations are carried out in MATLAB software using ode45 and fdel2.

关键词： Caputo fractional derivative basic reproduction number stability analysis sensitivityanalysis vaccination

Focal Nodular Hyperplasia: A Comprehensive Review with a Particular Focus on Pathogenesis and Complications

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Journal of Clinical and Translational Hepatology 2024年第2期12卷 182-190页

作者： Jaimy Villavicencio Kim George Y.Wu division of Gastroenterology-Hepatology University of Connecticut Health CenterFarmingtonCTUSA

Focal nodular hyperplasia is a benign tumor of the liver that is often found incidentally with *** purpose of this review is to discuss the pathophysiology,rare complications that can occur due to these lesions,and management options.A literature review was performed on clinical trials and case reports involving focal nodular hyperplasia complications and management of these,as well as the proposed pathogenesis underlying these *** exposure to oral contraceptive pills and endogenous hormones have been thought to play a role in the development of these lesions,this has not been *** recently,they are thought to arise as a consequence of a vascular anomaly causing alterations in the expression of angiopoietin *** are rare,but previous cases have reported associated pain,rupture and compression of nearby structures(hepatic vein,stomach,biliary system).Resection of focal nodular hyperplasia is not usually ***,if there is associated pain with no other identifiable cause or presence of a large or growing lesion with risk of causing a complication,then surgical resection,radiofrequency ablation or arterial embolization should be considered.

关键词： Focal nodular hyperplasia Oral contraceptives Liver lesion