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Prediction of ball-on-plate friction and wear by ANN with data-driven optimization

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Friction 2024年第6期12卷 1235-1249页

作者： alexander KOVALEV Yu TIAN Yonggang MENG State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

For training artificial neural network(ANN),big data either generated by machine or measured from experiments are used as input to"learn"the unspecified functions defining the *** experimental data are fed directly into the optimizer allowing training to be performed according to a predefined loss *** predict sliding friction and wear at mixed lubrication conditions,in this study a specific ANN structure was so designed that deep learning algorithms and data-driven optimization models can be *** ball-on-plate friction and wear data were analyzed using the specific training procedure to optimize the weights and biases incorporated into the neural layers of the ANN,and only two independent experimental data sets were used during the ANN optimization *** the training procedure,the ANN is capable to predict the contact and hydrodynamic pressure by adapting the output data according to the tribological condition implemented in the optimization algorithm.

关键词： machine learning deep learning artificial neural network mixed lubrication

Architecture of the Graphics System for Embedded Real-Time Operating Systems

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Tsinghua Science and Technology 2023年第3期28卷 541-551页

作者： alexander Giatsintov Kirill Mamrosenko Pavel Bazhenov Center of Visualization and Sattelite Information Technologies SRISA RASMoscow 117218Russia

This paper presents a new architecture of a graphics system for microkernel operating systems,including real-time operating *** following major parts of the architecture are presented:a user-level subsystem responsible for interaction with user applications;a bottom-level subsystem providing the functionality for graphics drivers,such as managing graphics output,video memory management,etc.;a kernel-level subsystem providing interaction with the kernel,and performing low-level operations,such as working with physical memory,processes,*** mechanisms of interaction of user applications with the user level of the graphics system,as well as interaction of the different levels of the graphics subsystem are *** paper pays much attention to various approaches to testing:the use of unit testing,testing using hardware and software *** important characteristic of a graphics system is its performance,in particular the performance of low-level operations such as memory allocation:the developed architecture suggests using a separate memory allocator which is faster than standard memory allocation *** of the performances of graphics system implementation for microkernel real-time operating system and graphics server Xorg is presented,showing significant superiority of the proposed architecture in a number of work scenarios.

关键词： operating system graphics system visualization system programming real-time operating system(RTOS) real-time

SnSi nanocrystals of zinc-blende structure in a Si matrix

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Nano Research 2015年第12期8卷 3905-3911页

作者： alexander Tonkikht Andrey Klavsyuk Nikolay Zakharov alexander Saletsky Peter Werner Max Planck Institute of Microstructure Physics Halle(Saale) 06120 Germany Faculty of Physics Moscow State University Moscow 119991 Russian Federation

A zinc-blende （sphalerite） crystallographic structure of SnSi nanocrystals generated by molecular-beam epitaxy is observed by electron microscopy techniques in a Si matrix. Ab initio density-functional modeling reveals a stabilizing effect of the Si matrix, which results in the lowest formation enthalpy of SnSi nanocrystals having the unexpected zinc-blende structure. Such nanocrystals could be applied in Si photonics to function as non-centrosymmetric media for the nonlinear optical process of second harmonic generation.

关键词： epitaxy density functional theory zinc-blende Si-Sn alloy

Improved proper motion determinations for 15 open clusters based on the UCAC4 catalog

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Research in Astronomy and Astrophysics 2016年第7期16卷 39-46页

作者： alexander Kurtenkov Nadezhda Dimitrova alexander Atanasov Teodor D.Aleksiev Department of Astronomy University of Sofia5 James Bourchier Blvd.1164 SofiaBulgaria Institute of Astronomy and National Astronomical Observatory Bulgarian Academy of Sciences72 Tsarigradsko Shose Blvd.1784 SofiaBulgaria Anglo-American School of Sofia 1 Siyanie Str.1138 SofiaBulgaria Geo Milev High School of Mathematics Storgozia5802 PlevenBulgaria Sofia High School of Mathematics 61 Iskar Str.1000 SofiaBulgaria

The proper motions of 15 nearby（d 〈 1 kpc） open clusters（OCs） were recalculated using data from the UCAC4 catalog. Only evolved or main sequence stars inside a certain radius from the center of the cluster were used. The results significantly differ from the ones presented by Dias et al.（2014）. This could be explained by a different approach in which we take the field star contamination into account. The present work aims to emphasize the importance of applying photometric criteria for the calculation of OC proper motions.

关键词： proper motions Galaxy open clusters and associations general

How big can a walking fish be?A theoretical inference based on observations on four land-dwelling fish genera of South Vietnam

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Integrative Zoology 2022年第5期17卷 849-878页

作者： alexander N.KUZNETSOV Borissiak Paleontological Institute Russian Academy of SciencesMoscowRussia

Comparative study of terrestrial locomotion of 4ﬁsh genera including Anabas,Channa,Clarias,and Monopterus,was performed in experimental setting with the substrate surface of wet *** special adaptations for terrestrial locomotion were ***ﬁsh uses for propulsion on land what it already ***-shaped Monopterus crawls by body undulations in a serpentine or sidewinding technique,the latter of which was not previously observed beyond *** other 3ﬁsh genera walk by body oscillations using stiff appendages as *** they are located anteriorly,as the serrate operculum in Anabas and the preaxial spine of the pectoralﬁn in Clarias,the propulsion is termed prolocomotor,when posteriorly,as the spiny analﬁn in Channa—*** is the heaviestﬁsh walking out of water in our days,quite comparable in size withﬁrst Devonian tetrapods Acan-thostega and Tulerpeton.A theoretical calculation is suggested for the upper size limit of aﬁsh capable of terrestrial walking without special locomotor *** should be roughly 20 cm in the vertical dimension of the trunk,which is just a little above the known size of Devonian tetrapodomorphﬁshes Panderichthys and *** metalocomotor walking technique of Channa is suggested as the closest extant model for terrestrial locomotion at theﬁsh-tetrapod *** major difference is that the metalocomotor propulsor in Channa is represented by the analﬁn,while in tetrapodomorphs by the pelvicﬁ*** sprawled pelvicﬁns were advantageous in respect of reduced requirement for side-to-side tail swinging.

关键词： ﬁsh-tetrapod transition metalocomotor propulsion prolocomotor propulsion snakehead

Statistical Estimation of the Shannon Entropy

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Acta Mathematica Sinica,English Series 2019年第1期35卷 17-46页

作者： alexander BULINSKI Denis DIMITROV Steklov Mathematical Institute of Russian Academy of Sciences and Department of Mathematics and Mechanics Lomonosov Moscow State UniversityMoscow 119234Russia

The behavior of the Kozachenko–Leonenko estimates for the(differential) Shannon entropy is studied when the number of i.i.d. vector-valued observations tends to infinity. The asymptotic unbiasedness and L^2-consistency of the estimates are established. The conditions employed involve the analogues of the Hardy–Littlewood maximal function. It is shown that the results are valid in particular for the entropy estimation of any nondegenerate Gaussian vector.

关键词： Shannon differential entropy Kozachenko-Leonenko estimates Hardy-Littlewood maxi-mal function analogues asymptotic unbiasedness and L^2-consistency Gaussian vectors

Examples of unbounded homogeneous domains in complex space

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Science China Mathematics 2005年第Z1期48卷 248-261页

作者： Michael Eastwood alexander Isaev Department of Pure Mathematics University of Adelaide South Australia 5005AustraliaDepartment of Mathematics The Australian National UniversityCanberraACT 0200Australia

We present several examples of homogeneous domains in complex space that do not have bounded realisations. The domains are equivalent to tubes over affinely homogeneous domains in real space.

关键词： homogeneous unbounded domains.

Hebbian plasticity:the elusive missing link at the heart of Alzheimer’s disease pathogenesis?

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Neural Regeneration Research 2023年第1期18卷 123-124页

作者： alexander F.Jeans Department of Pharmacology University of OxfordOxfordUK

The amyloid cascade hypothesis of Alzheimer’s pathogenesis:The amyloid cascade hypothesis of Alzheimer’s disease(AD)pathogenesis will shortly celebrate its thirtieth birthday(Hardy and Higgins,1992).Based on abundant genetic and biochemical evidence,it proposes that deposition of the amyloid-β(Aβ)peptide in brain parenchyma is an essential upstream trigger in AD pathogenesis that drives a cascade of events,specifically including the recruitment and pathological hyper-phosphorylation of the micro-tubule-associated protein tau,that culminate in derangement of synaptic function and,eventually,neuronal death.

关键词： pathogenesis Alzheimer eventually

Strategies to prevent and detect intraoperative spinal cord ischemia during complex aortic surgery:from drainages and biomarkers

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Neural Regeneration Research 2021年第4期16卷 678-679页

作者： alexander Gombert Florian Simon Department of Vascular Surgery University Hospital RWTH Aachen AachenGermany Department of Vascular and Endovascular Surgery Heinrich-Heine-University of DüsseldorfDüsseldorfGermany

Spinal cord ischemia(SCI),a frequent complication following open and endovascular thoracoabdominal aortic aneurysm(TAAA)repair,is a feared complication with relevant impact on a patient's quality of *** the early days of open TAAA repair,more than one third of the patients suffered from ***,due to improved preventive measures and the option of staged endovascular TAAA repair,10%of all patients are affected by spinal cord problems after TAAA repair(Rocha et al.,2020).

关键词： ischemia aortic SCI