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Research on the mechanism of the two-dimensional ultrasonic surface burnishing process to enhance the wear resistance for aluminum alloy

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Friction 2024年第3期12卷 490-509页

作者： Zhen-yu ZHOU Qiu-Yang ZHENG yu LI Cong DING Guang-Jian PENG zhong-yu piao College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Ministry of Education and Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310014China

The gradient nanostructure is machined on the aluminum(Al)alloy by the two-dimensional ultrasonic surface burnishing process(2D-USBP).The mechanism of why the gradient nanostructure enhances wear resistance is *** mechanical properties and microstructure characterization for the gradient nanostructure are performed by operating a nanoindenter,transmission electron microscopy(TEM),and electron backscattered diffraction(EBSD).Dry wear tests are performed on the samples before and after machining to evaluate the wear resistance and *** effect of the gradient nanostructure on the wear resistance is explored by developing the crystal plasticity(CP)finite element and molecular dynamics(MD)*** characterization results show that the 2D-USBP sample prepared a gradient structure of~600μm thick on the aluminum surface,increasing the surface hardness from 1.13 to 1.71 GPa and reducing the elastic modulus from 78.84 to 70.14 *** optimization of the surface microstructure and the increase of the mechanical properties effectively enhance the wear resistance of the sample,with 41.20%,39.07%,and 54.58% of the wear scar areas for the 2D-USBP treated samples to the original samples under 5,10,and 15 N loads,*** gradient nanostructure hinders the slip of dislocations inside the sample during the wear process and reduces the size and scope of plastic deformation;meanwhile,the resistance to deformation,adhesion,and crack initiation and propagation of the sample surface is improved,resulting in enhanced wear resistance.

关键词： structural superlubricity lattice registry elastic deformation strained solitons crystal plasticity molecular dynamics simulations

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Accumulated damage process of thermal sprayed coating under rolling contact by acoustic emission technique

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Frontiers of Mechanical Engineering 2016年第3期11卷 227-232页

作者： Jia XU Zhen-yu ZHOU zhong-yu piao Key Laboratory of Special Purpose Equipment and Advanced Processing Technology (Zhejiang University of Technology) Ministry ofEducation and Zhejiang Province Hangzhou 310014 China Key Laboratory of Special Purpose Equipment and Advanced Processing Technology (Zhejiang University of Technology) Ministry ofEducation and Zhejiang Province Hangzhou 310014 China The StateKey Laboratory of Fluid Power Transmission and Control Hangzhou310027 China

The accumulated damage process of rolling contact fatigue （RCF） of plasma-sprayed coatings was investigated. The influences of surface roughness, loading condition, and stress cycle frequency on the accumulated damage status of the coatings were discussed. A ball-on- disc machine was employed to conduct RCF experiments. Acoustic emission （AE） technique was introduced to monitor thc RCF process of the coatings. AE signal characteristics were investigated to reveal the accumulated damage process. Result showed that the polished coating would resist the asperity contact and remit accumulated damage. The RCF lifetime would then extend. Heavy load would aggravate the accumulated damage status and induce surface fracture. Wear became the main failure mode that reduced the RCF lifetime. Frequent stress cycle would aggravate the accumulated damage status and induce interface fracture. Fatigue then became the main failure mode that also reduced the RCF lifetime.

关键词： accumulated damage spray coating rolling contact fatigue acoustic emission

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Clinical characteristics and treatment of splenic infarction in children with systemic lupus erythematosus

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World Journal of Pediatrics 2024年第5期20卷 525-531页

作者： Yan Li yu-Rong piao Tong-Xin Han Hua-Wei Mao Department of Immunology Ministry of Education Key Laboratory of Major Diseases in ChildrenBeijing Key Laboratory for Genetics of Birth DefectsNational Center for Children’s HealthBeijing Children’s HospitalCapital Medical UniversityNo.56 Nan Li Shi LuBeijing100045China

Splenic infarction(SI)is a rare clinical phenomenon that occurs when the blood supply to the spleen is interrupted,resulting in tissue ischemia and necrosis[1].There are many causes of SI;in adult patients,cardioembolism,hematological malignancy,and infectious disease are the most common[2].Rheumatic diseases,especially systemic lupus erythematosus(SLE)and granulomatosis with polyangitis,can also lead to SI[3];however,only a few cases have been *** are currently no statistically meaningful data on the etiology of SI in *** most patients with SI can recover after conservative treatment,a small number of patients develop complications,such as splenic abscess,splenic rupture,splenic hemorrhage,and hemoperitoneum,and may even undergo splenectomy in severe cases.

关键词： erythematosus lupus treatment

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Does the continuous wetting of the Tibetan Plateau contribute to the accelerated degradation of permafrost?

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Science China Earth Sciences 2024年第5期67卷 1714-1718页

作者： yuyang WANG Jinzhi DING Shilong piao Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking UniversityBeijing 100871China State Key Laboratory of Tibetan Plateau Earth System Environment and ResourcesInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

Global warming is causing the Tibetan permafrost to degrade, as evidenced by rising ground temperatures, thicker active layer thickness, thinner permafrost layer, and melting underground ice, etc.(Ran et al., 2018;Wang et al., 2020).The degradation of permafrost not only profoundly alters the carbon cycling processes in high-altitude ecosystems,thereby influencing the regional climate system, but also affects landscape hydrological connectivity。

关键词： Tibetan landscape altitude

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A Case of Brucellosis Concomitant with Severe Fever with Thrombocytopenia Syndrome—Weifang City,Shandong Province,China,2023

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China CDC weekly 2024年第27期6卷 677-680页

作者： Qingqing Xu Cuiping Wu Hui Liu Chao Geng Jinhui Zhang Dongri piao Hongyan Zhao yu Fan Guozhong Tian Hai Jiang National Key Laboratory of Intelligent Tracing and Forecasting for Infectious Diseases National Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina Department of Infectious Diseases Yidu Central Hospital of WeifangWeifang CityShandong ProvinceChina Institute of Bacterial Disease Jinan Center for Disease Control and PreventionJinan CityShandong ProvinceChina Tongliao Center for Disease Control and Prevention Tongliao CityInner Mongolia Autonomous RegionChina

Summary What is already known about this topic?Brucellosis and severe fever with thrombocytopenia syndrome(SFTS)are neglected zoonoses,attributable respectively to Brucella and the SFTS virus(SFTSV).While the incidence of these diseases has been rising,instances of co-infection remain *** is added by this report?This represents the first documented case of a rare coinfection involving Brucella and SFTSV.

关键词： neglected instance Shandong

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UAV maneuvering decision-making algorithm based on deep reinforcement learning under the guidance of expert experience

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Journal of Systems Engineering and Electronics 2024年第3期35卷 644-665页

作者： ZHAN Guang ZHANG Kun LI Ke piao Haiyin School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710072China Science and Technology on Electro-Optic Control Laboratory Luoyang 471009China

Autonomous umanned aerial vehicle(UAV) manipulation is necessary for the defense department to execute tactical missions given by commanders in the future unmanned battlefield. A large amount of research has been devoted to improving the autonomous decision-making ability of UAV in an interactive environment, where finding the optimal maneuvering decisionmaking policy became one of the key issues for enabling the intelligence of UAV. In this paper, we propose a maneuvering decision-making algorithm for autonomous air-delivery based on deep reinforcement learning under the guidance of expert experience. Specifically, we refine the guidance towards area and guidance towards specific point tasks for the air-delivery process based on the traditional air-to-surface fire control ***, we construct the UAV maneuvering decision-making model based on Markov decision processes(MDPs). Specifically, we present a reward shaping method for the guidance towards area and guidance towards specific point tasks using potential-based function and expert-guided advice. The proposed algorithm could accelerate the convergence of the maneuvering decision-making policy and increase the stability of the policy in terms of the output during the later stage of training process. The effectiveness of the proposed maneuvering decision-making policy is illustrated by the curves of training parameters and extensive experimental results for testing the trained policy.

关键词： unmanned aerial vehicle(UAV) maneuvering decision-making autonomous air-delivery deep reinforcement learning reward shaping expert experience

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Tube-based robust reinforcement learning for autonomous maneuver decision for UCAVs

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Chinese Journal of Aeronautics 2024年第7期37卷 391-405页

作者： Lixin WANG Sizhuang ZHENG Haiyin piao Changqian LU Ting yuE Hailiang LIU School of Aeronautical Science and Engineering Beihang UniversityBeijing 100191China Shenyang Aircraft Design&Research Institute Shenyang 110035China

Reinforcement Learning(RL)algorithms enhance intelligence of air combat AutonomousManeuver Decision(AMD)policy,but they may underperform in target combat environmentswith *** enhance the robustness of the AMD strategy learned by RL,thisstudy proposes a Tube-based Robust RL(TRRL)***,this study introduces a tube todescribe reachable trajectories under disturbances,formulates a method for calculating tubes basedon sum-of-squares programming,and proposes the TRRL algorithm that enhances robustness byutilizing tube size as a quantitative ***,this study introduces offline techniques forregressing the tube size function and establishing a tube library before policy learning,aiming toeliminate complex online tube solving and reduce the computational burden during ***,an analysis of the tube library demonstrates that the mitigated AMD strategy achievesgreater robustness,as smaller tube sizes correspond to more cautious *** finding highlightsthat TRRL enhances robustness by promoting a conservative *** effectively balanceaggressiveness and robustness,the proposed TRRL algorithm introduces a“laziness factor”as aweight of ***,combat simulations in an environment with disturbances confirm thatthe AMD policy learned by the TRRL algorithm exhibits superior air combat performance comparedto selected robust RL baselines.

关键词： Air combat Autonomous maneuver decision Robust reinforcement learning Tube-based algorithm Combat simulation

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Mapping the intellectual structure and emerging trends for the application of nanomaterials in gastric cancer:A bibliometric study

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 2181-2199页

作者： Bo-Na Liu Xiao-Li Gao Ying piao Department of Oncology General Hospital of Northern Theater CommandShenyang 110015Liaoning ProvinceChina

BACKGROUND Recent reviews have outlined the main nanomaterials used in relation to gastrointestinal tumors and described the basic properties of these ***,the research hotspots and trends in the application of nanomaterials in gastric cancer(GC)remain *** To demonstrate the knowledge structure and evolutionary trends of research into the application of nanomaterials in *** Publications related to the application of nanomaterials in GC were retrieved from the Web of Science Core Collection for this systematic review and bibliometric *** and CiteSpace were used for bibliometric and visualization *** From 2000 to 2022,the application of nanomaterials in GC developed *** keyword co-occurrence analysis showed that the related research topics were divided into three clusters:(1)The application of nanomaterials in GC treatment;(2)The application and toxicity of nanomaterials in GC diagnosis;and(3)The effects of nanomaterials on the biological behavior of GC ***,silver nanoparticles,and green synthesis are the latest high-frequency keywords that represent promising future research *** The application of nanomaterials in GC diagnosis and treatment and the mechanisms of their effects on GC cells have been major themes in this field over the past 23 years.

关键词： Nanomaterials Gastric cancer Bibliometrics Drug delivery VOSviewer CiteSpace Systematic review

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The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

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Genes & Diseases 2024年第3期11卷 155-187页

作者： Michael yu Kevin Qin Jiaming Fan Guozhi Zhao piao Zhao Wei Zeng Connie Chen Annie Wang Yonghui Wang jiamin zhong Yi Zhu William Wagstaff Rex C.Haydon Hue H.Luu Sherwin Ho Michael J.Lee Jason Strelzow Russell R.Reid Tong-Chuan He School of Medicine Rosalind Franklin University of Medicine and ScienceNorth ChicagoIL 60064USA Molecular Oncology Laboratory Department of Orthopedic Surgery and Rehabilitation MedicineThe University of Chicago Medical CenterChicagoIL 60637USA Ministry of Education Key Laboratory of Diagnostic Medicine and Department of Clinical BiochemistryThe School of Laboratory MedicineChongqing Medical UniversityChongqing 400016China Department of Orthopedic Surgery The First Affliated Hospital of Chongqing Medical UniversityChongqing 400016China Department of Urology The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016China Department of Clinical Laboratory Medicine Shanghai Jiaotong University School of MedicineShanghai 200000China Department of Orthopaedic Surgery Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100730China Laboratory of Craniofacial Suture Biology and Development Department of Surgery Section of Plastic SurgeryThe University of Chicago Medical CenterChicagoIL 60637USA Department of Neurology The First Dongguan Affiliated HospitalGuangdong Medical UniversityDongguanGuangdong 523475China

The evolutionarily conserved Wnt signaling pathway plays a central role in develop-ment and adult tissue homeostasis across *** proteins are secreted,lipid-modified signaling molecules that activate the canonical(β-catenin dependent)and non-canonical(β-catenin independent)Wnt signaling *** behaviors such as proliferation,differ-entiation,maturation,and proper body-axis specification are carried out by the canonical pathway,which is the best characterized of the known Wnt signaling *** signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various *** includes but is not limited to embryonic,hematopoietic,mesenchymal,gut,neural,and epidermal stem *** signaling has also been implicated in tumor cells that exhibit stem cell-like *** signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone *** surprisingly,aberrant Wnt signaling is also associated with a wide variety of diseases,including *** of Wnt pathway members in cancer can lead to unchecked cell proliferation,epithelial-mesenchymal transition,and ***,advances in the understand-ing of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt *** with a brief overview of the mechanisms of canonical and non-canonical Wnt,this review aims to summarize the cur-rent knowledge of Wnt signaling in stem cells,aberrations to the Wnt pathway associated with diseases,and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

关键词： β-Catenin Cancer Canonical Wnt Disease Non-canonical Wnt Stem cells Targeted therapy Wnt signaling

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Growth performance,serum parameters,inflammatory responses,intestinal morphology and microbiota of weaned piglets fed 18%crude protein diets with different ratios of standardized ileal digestible isoleucine to lysine

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Animal Nutrition 2024年第1期16卷 313-325页

作者： Jian Wang Sujie Liu Jiayu Ma Xiaoli Dong Shenfei Long Xiangshu piao State Key Laboratory of Animal Nutrition College of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China Beijing Jingwa Agricultural Science and Technology Innovation Center Beijing101206China CJ International Trading Co. LtdShanghai 201107China

The present study was to explore the Ile requirement of piglets fed 18%crude protein(CP)*** hundred and fifty 28-day-old Duroc×Landrace×Yorkshire piglets(8.37±1.92 kg)were randomly divided into 5 dietary treatments(10 piglets per replicate,5 barrows and 5 gilts per replicate)with 45%,50%,55%,60%,65%standardized ileal digestible(SID)Ile-to-Lys ratios,and the SID Lys was formulated to1.19%.The experimental design consisted of two phases(d 1 to 14 and d 15 to 28).Results showed that average daily gain(ADG)had a tendency to quadratically increase as the SID Ile-to-Lys ratio increased(P=0.09),and the optimum SID Ile-to-Lys ratios required to maximize ADG were 48.33%and 54.63%for broken-line linear model and quadratic polynomial model,*** SID Ile-to-Lys ratios had no significant effects on average daily feed intake and gain-to-feed *** matter(P<0.01),CP(P=0.01),ether extract(P=0.04),gross energy(P<0.01)and organic matter(P<0.01)digestibility increased *** total cholesterol levels decreased linearly(P=0.01)and quadratically(P<0.01);aspartate aminotransferase(P<0.01),interleukin-1β(P=0.01),and tumor necrosis factor-a(P<0.01)levels decreased quadratically;immunoglobulin G(P=0.03)and immunoglobulin M(P=0.01)concentrations increased *** Ser levels decreased linearly(P<0.01)and quadratically(P=0.01);Glu(P=0.02),Arg(P=0.05),and Thr(P=0.03)levels decreased quadratically;Gly(P<0.01)and Leu(P=0.01)levels decreased linearly;Ile(P<0.01)concentration increased *** villus height(P<0.01)and villus height to crypt depth ratio(P<0.01)increased *** deficiency or excess of Ile decreased short chain fatty acid-producing bacteria abundance and increased pathogenic bacteria ***,taking ADG as the effect index,the optimum SID Ile-to-Lys ratios of piglets offered 18%CP diets were 48.33%and 54.63%based on two different statistical models,respectively,and the deficiency or excess of lle negative

关键词： Weaned piglet Growth performance Intestinal health Isoleucine Reduced crude protein diet

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