检索结果-南通市图书馆

Suppressing filamentation instability due to laser beam self-filtering

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2024年第3期12卷 51-61页

作者： dmitry Silin Efim Khazanov A.V.Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences Nizhny NovgorodRussia

The development of small-scale self-focusing in a nonlinear Kerr medium after preliminary self-filtering of a laser beam propagating in free space is studied *** is shown that,under definite conditions,due to self-filtering,filamentation instability(beam splitting into filaments)either occurs at significantly larger values of the B-integral,or does not occur at *** the latter case,there develops the honeycomb instability revealed in this *** instability is the formation of a random honeycomb structure in the beam *** is shown that self-filtering can significantly increase the permissible values of the B-integral,at which the beam quality remains acceptable.

关键词： filamentation instability honeycomb instability self-filtering small-scale self-focusing

Formation of diffuse and spark discharges between two needle electrodes with the scattering of particles

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2024年第9期26卷 32-39页

作者： Victor F TARASENKO dmitry V BELOPLOTOV Alexei N PANCHENKO dmitry A SOROKIN Institute of High Current Electronics Siberian BranchRussian Academy of SciencesTomsk 634055Russia National Research Tomsk State University Tomsk 634050Russia

The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark *** and negative nanosecond voltage pulses with an amplitude of tens of kilovolts were ***-resolved images of the discharge development were taken with a fourchannel Intensified Charge Coupled Device(ICCD)*** minimum delay between the camera channels could be as short as≈0.1 *** made it possible to study the gap breakdown process with subnanosecond *** was observed that a wide-diameter streamer develops from the high-voltage pointed *** ionization processes near the grounded pin electrode started when the streamer crossed half of the *** bridging the gap by the streamer,a diffuse discharge was *** development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next *** was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter *** thin luminous tracks were observed against the background of a discharge plasma *** has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.

关键词： needle electrodes short voltage pulses atmospheric air streamer breakdown diffuse and spark discharges scattering metal particles

A New Generation of Rules-based Approach:Mivar-based Intelligent Planning of Robot Actions(MIPRA)and Brains for Autonomous Robots

在线全文

学校读者我要写书评

暂无评论

Machine Intelligence Research 2024年第5期21卷 919-940页

作者： Oleg Varlamov dmitry Aladin Department of Information Processing and Management Systems RI MIVARBauman Moscow State Tchnical University(BMSTU)Moscow105005Russian Federation

To create autonomous robots,both hardware and software are *** enormous progress has already been made in the field of equipment,then robot software depends on the development of artificial *** article proposes a solution for creating“logical”brains for autonomous robots,namely,an approach for creating an intelligent robot action planner based on Mivar expert *** application of this approach provides opportunities to reduce the computational complexity of solving planning problems and the requirements for the computational characteristics of hardware platforms on which intelligent planning systems are *** theoretically and practically justify the expediency of using logically solving systems,in particular Mivar expert systems,to create intelligent planners,the MIPRA(Mivar-based Intelligent Planning of Robot Actions)planner was created to solve problems such as STRIPS for permutation cubes in the Blocks World *** planner is based on the platform for creating expert systems of the *** a result,the Mivar planner can process information about the state of the subject area based on the analysis of cause-effect relationships and an algorithm for automatically constructing logical inference(finding a solution from“Given”to“Find”).Moreover,an important feature of the MIPRA is that the system is built on the principles of a“white box”,due to which the system can explain any of its decisions and provide justification for the actions performed in the form of a retrospective of the stages of the decision-making *** preparing a set of robot actions aimed at changing control objects,expert knowledge is used,which is the basis for the functioning algorithms of the *** approach makes it possible to include an expert in the process of organizing the work of the intelligent planner and use existing knowledge about the subject *** experiments of this study have shown that instead of many hours and powerfu

关键词： Autonomous robot blocks world decision-making system expert systems intelligent planning

Source localization based on field signatures:Laboratory ultrasonic validation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2024年第3期22卷 47-56页

作者： Mahmoud Eissa dmitry Sukhanov Department of Radiophysics Tomsk State UniversityTomsk634050Russia Higher Institute for Applied Sciences and Technology(HIAST) Damascus31983Syria

Location awareness in wireless networks is essential for emergency services,navigation,gaming,and many other *** article presents a method for source localization based on measuring the amplitude-phase distribution of the field at the base *** existing scatterers in the target area create unique scattered field interference at each source *** unique field interference at each source location results in a unique field signature at the base station which is used for source *** the proposed method,the target area is divided into a grid with a step of less than half the *** grid node is characterized by its field signature at the base *** signatures corresponding to all nodes are normalized and stored in the base station as fingerprints for source *** normalization of the field signatures avoids the need for time synchronization between the base station and the *** a source transmits signals,the generated field signature at the base station is normalized and then correlated with the stored *** maximum correlation value is given by the node to which the source is the *** simulations and results of experiments on ultrasonic waves in the air show that the ultrasonic source is correctly localized using broadband field signatures with one base station and without time *** proposed method is potentially applicable for indoor localization and navigation of mobile robots.

关键词： Base station Field signature Fingerprints Localization Ultrasonic frequencies

Microstructure and thermal properties of dissimilar M300–CuCr1Zr alloys by multi-material laser-based powder bed fusion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 118-128页

作者： Xiaoshuang Li dmitry Sukhomlinov Zaiqing Que Aerosint SA B-4040 HerstalBelgium Aalto University Department of Chemical and Metallurgical EngineeringEspoo 02150Finland VTT Technical Research Centre of Finland Espoo 02044Finland

Multi-material laser-based powder bed fusion (PBF-LB) allows manufacturing of parts with 3-dimensional gradient and additional functionality in a single step. This research focuses on the combination of thermally-conductive CuCr1Zr with hard M300 tool *** interface configurations of M300 on CuCr1Zr and CuCr1Zr on M300 were investigated. Ultra-fine grains form at the interface due to the low mutual solubility of Cu and steel. The material mixing zone size is dependent on the configurations and tunable in the range of0.1–0.3 mm by introducing a separate set of parameters for the interface layers. Microcracks and pores mainly occur in the transition *** of these defects, the thermal diffusivity of bimetallic parts with 50vol% of CuCr1Zr significantly increases by 70%–150%compared to pure M300. The thermal diffusivity of CuCr1Zr and the hardness of M300 steel can be enhanced simultaneously by applying the aging heat treatment.

关键词： multi-material additive manufacturing laser-based powder bed fusion thermal diffusivity dissimilar metals copper alloy

Phase Transition in a Dense Swarm of Self-Propelled Bots

在线全文

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2024年第8期20卷 1785-1798页

作者： dmitry Bratsun Kirill Kostarev Applied Physics Department Perm National Research Polytechnic UniversityPerm614990Russia

Swarms of self-organizing bots are becoming important elements in various technical systems,which include the control of bacterial cyborgs in biomedical applications,technologies for creating new metamaterials with internal structure,self-assembly processes of complex supramolecular structures in disordered media,*** this work,we theoretically study the effect of sudden fluidization of a dense group of bots,each of which is a source of heat and follows a simple algorithm to move in the direction of the gradient of the global temperature *** show that,under certain conditions,an aggregate of self-propelled bots can fluidize,which leads to a second-order phase *** bots’program,which forces them to search for the temperature field maximum,acts as an effective buoyancy *** a consequence,one can observe a sudden macroscopic circulation of bots from the edge of the group to its center and back again,which resembles classical Rayleigh-Benard thermal *** the continuum approximation,we have developed a mathematical model of the phenomenon,which reduces to the equation of a self-gravitating porous disk saturated with an incompressible fluid that generates *** derive governing equations in the Darcy-Boussinesq approximation and formulate a nonlinear boundary value *** exact solution to the linearized problem for infinitesimal perturbations of the base state is obtained,and the critical values of the control parameter for the onset of the bot circulation are *** we apply weakly nonlinear analysis using the method of multiple time *** found that as the number of bots increases,the swarm exhibits increasingly complex patterns of circulation.

关键词： Active matter collective behavior self-organization convection

Alterations of protein homeostasis in Alzheimer's disease:beyond Procrustean bed of endoplasmic reticulum stress and unfolded protein response

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第8期19卷 1645-1646页

作者： dmitry Lim Alexei Verkhratsky Department of Pharmaceutical Sciences Universitàdel Piemonte Orientale“Amedeo Avogadro”NovaraItaly Faculty of Biology Medicine and HealthThe University of ManchesterManchesterUK Achucarro Center for Neuroscience IKERBASQUEBasque Foundation for ScienceBilbaoSpain&Department of NeurosciencesUniversity of the Basque Country UPV/EHU and CIBERNEDLeioaSpain Department of Stem Cell Biology State Research Institute Centre for Innovative MedicineVilniusLithuania Department of Forensic Analytical Toxicology School of Forensic MedicineChina Medical UniversityShenyangLiaoning ProvinceChina

Alzheimer’s disease(AD)is a major age-related form of dementia with a number of cases exponentially growing,causing enormous social and economic impact on individuals and *** hallmarks of AD,evident in postmortem AD brains,include a massive loss of the grey matter in the neocortex,extracellular deposition of amyloid-β(Aβ)in the form of senile plaques and cerebrovascular amyloid angiopathy,and intra-neuronal accumulation of neurofibrillary tangles,formed by hyper-phosphorylated tau protein.

关键词： Alzheimer homeostasis cortex

History of chronic gastritis:How our perceptions have changed

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第13期30卷 1851-1858页

作者： dmitry Bordin Maria Livzan Department of Pancreatic Biliary and Upper GI Tract DiseasesA.S.Loginov Moscow Clinical Scientific CenterMoscow 111123Russia Department of Propaedeutic of Internal Diseases and Gastroenterology Russian University of MedicineMoscow 127006Russia Department of Outpatient Therapy and Family Medicine Tver State Medical UniversityTver 170100Russia Department of Internal Medicine and Gastroenterology Omsk State Medical UniversityOmsk 644099Russia

Currently,the diagnostic strategy for chronic gastritis(CG)is aimed not just at fixing the presence of gastric mucosal inflammation,but also at gastric cancer(GC)risk stratification in a particular *** classification approach with the definition of the stage of gastritis determines the need,activities and frequency of dynamic monitoring of a ***,this attitude to the patient suffering from CG was far from *** present publication is a literature review describing the key milestones in the history of CG research,from the description of the first observations of inflammation of the gastric mucosa,assessment of gastritis as a predominantly functional disease,to the advent of endoscopy of the upper digestive tract and diagnostic gastric biopsy,assessment of the role of Helicobacter pylori infection in progression of inflammatory changes to atrophy,intestinal metaplasia,dysplasia and GC.

关键词： Chronic gastritis Intestinal metaplasia Dysplasia Gastric cancer Helicobacter pylori

Probing the endoplasmic reticulummitochondria interaction in Alzheimer's disease:searching far and wide

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第10期19卷 2103-2104页

作者： Giulia Dematteis Laura Tapella dmitry Lim Department of Pharmaceutical Sciences Universitàdel Piemonte Orientale“Amedeo Avogadro”NovaraItaly

Alzheimer's disease(AD)is the most frequent,form of dementia in elderly people and is an incurable disease with an exponentially growing number of *** deposition of amyloid-β(Aβ)plaques and intraneuronal formation o... 详细信息

关键词： Alzheimer Aβ reticulum