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Scalable nanocomposite parylene-based memristors:Multifilamentary resistive switching and neuromorphic applications

Nano Research 2023年第2期16卷 3207-3214页

作者： Anna N.Matsukatova Artem Yu.Vdovichenko Timofey D.Patsaev pavel A.Forsh pavel K.Kashkarov Vyacheslav A.Demin Andrey V.Emelyanov National Research Centre“Kurchatov Institute” Moscow 123182Russia Physics Department Lomonosov Moscow State UniversityMoscow 119991Russia Moscow Institute of Physics and Technology DolgoprudnyjMoscow oblast 141701Russia Enikolopov Institute of Synthetic Polymeric Materials Russian Academy of SciencesMoscow 117993Russia Physics Department Saint Petersburg State UniversitySt.Petersburg 199034Russia

Memristors are promising candidates for synapse emulation in brain-inspired neuromorphic computing *** main obstacle to their usage in such systems is high variability of memristive characteristics and its severe negative effect on the neural network *** paper addresses the issue from two points of view on the example of the parylene-based memristors:(i)the methods of the memristor internal stochasticity decrease and(ii)the methods of the memristive neural network architecture *** introduction of an optimal Ag nanoparticle concentration(3 vol.%–6 vol.%)to the memristive structure leads to a statistically significant decrease in the switching voltage variation and endurance ***,it is shown that post-fabrication annealing improves memristive characteristics,e.g.,resistive switching window increases by an order of magnitude and exceeds 106,the switching voltage variation decreases by a factor of 2(down to 7%for the set and 17%for the reset voltage),and thermostability is *** transmission electron microscopy and impedance spectroscopy analysis allowed establishing a multifilamentary resistive switching mechanism for nanocomposite parylene-based *** simulation of the formal neural network based on these memristors demonstrates high classification accuracy with low variation for an important biomedical task,heart disease prediction,after careful feature selection and network architecture *** prospects of the controlled incorporation of the nanocomposite parylene-based memristors in neural networks are brightened by their scaling possibility in crossbar geometry.

关键词： memristor resistive switching neuromorphic computing parylene nanocomposite

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Coordination Control of Power Flow Controller and Hybrid DC Circuit Breaker in MVDC Distribution Networks

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Journal of Modern Power Systems and Clean Energy 2021年第6期9卷 1257-1268页

作者： Jianquan Liao Niancheng Zhou Zian Qin pavel Purgat Qianggang Wang Pavol Bauer IEEE School of Electrical Engineering Sichuan University State Key Laboratory of Power Transmis-sion Equipment and System Security and New Technology Chongqing University Department of Electrical Sustainable Energy DC SystemsEnergy Conversion andStorage Group

The two main challenges of medium voltage direct current(MVDC)distribution network are the flexible control of power flow(PF)and fault *** this paper,the power flow controller(PFC)is introduced to regulate the PF and inhibit the fault current during the DC *** coordination strategy of series-parallel PFC(SP-PFC)and hybrid DC circuit breaker(DCCB)is *** regulating the polarity and magnitude of SP-PFC output voltage during the fault,the rising speed of fault current can be suppressed so as to reduce the breaking current of hybrid *** access mode of SP-PFC to the MVDC distribution network and its topology are analyzed,and the coordination strategy between SP-PFC and hybrid DCCB is ***,the emergency control and bypass control strategies of SP-PFC are *** this basis,the mathematical model of SP-PFC in different fault stages is *** the equivalent model of SP-PFC,the fault current of the MVDC distribution network can be calculated accurately.A simulation model of the MVDC distribution network containing SP-PFC is established in MATLAB/*** fault current calculation result is compared with the simulation result,and the effectiveness of the proposed coordination strategy is verified.

关键词： Medium voltage direct current(MVDC)distribution network fault current power flow controller(PFC) DC circuit breaker(DCCB)

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Numerical investigation of full scale coaxial main rotor aerodynamics in hover and vertical descent

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Chinese Journal of Aeronautics 2021年第5期34卷 666-683页

作者： pavel V.MAKEEV Yuri M.IGNATKIN Alexander I.SHOMOV Department of Helicopter Design Moscow Aviation Institute(National Research University)Moscow 125993Russia

The original free vortex wake model was used for numerical *** of the aerodynamic characteristics in hover and vertical descent modes in the range of vertical descent speed of 0–30 m/s including the Vortex Ring State(VRS)area was *** calculations were carried out under the condition of variable blade pitch angle values providing a fixed timeaverage thrust *** data of free vortex wake shapes,flow structures,and velocity fields were obtained and *** time-dependences of the rotor’s thrust and torque coefficients were obtained and *** obtained data allows determining the boundaries of the VRS area by various criteria such as rotor thrust and torque pulsations,growth of rotor power consumption relative to the hover,growth of rotor induced velocities relative to the hover,and growth of the required rotor blade pitch angles *** results of the study are compared with experimental and calculated data of other authors and can significantly supplement the available results of experimental and computational studies in this area.

关键词： Aerodynamic characteristics Coaxial rotor Free wake model Hover and vertical descent Vortex ring state mode

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Effect of the Laser Heating of Nanotube Nuclei on the Nanotube Type Population

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Nano Research 2009年第10期2卷 818-827页

作者： pavel Nikolaev William Holmes Edward Sosa Peter Boul Sivaram Arepalli Department of Energy Science Sungkyunkwan University300 Cheoncheon-dongJangan-guSuwon 440-746Korea Alan G.MacDiarmid NanoT ech Institute The University of Texas at Dallas800 West Campbell RoadRichardsonTX 75080USA ERC Inc./NASA Johnson Space Center Mail Stop ES-4P.O.Box 58561HoustonTX 77258USA

Many potential applications of carbon nanotubes are expected to benet from the availability of single-walled carbon nanotube materials enriched in metallic species,and specifically armchair *** present work focuses on the modification of the pulsed laser vaporization(PLV)technique to selectively produce certain carbon nanotube *** nuclei were“warmed-up”with an additional laser pulse,timed to coincide approximately with the nucleation *** effect of the second laser on the carbon vapor temperature was studied by emission *** type populations with and without warm-up were compared by means of absorption,photoluminescence,and Raman *** was found that the warm-up of nanotube nuclei with a laser pulse has a noticeable,albeit small,effect on the nanotube *** intensity of spectral features associated with(9,7)nanotube and its large chiral angle neighbors increased,while small chiral angle nanotubes decreased,with exception of the(15,0)*** experiment demonstrates that nanotube population during PLV synthesis can be manipulated in a controlled fashion.

关键词： Nanotube synthesis pulsed laser vaporization nanotube population

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Prognostics for Lithium-ion batteries for electric Vertical Take-off andLanding aircraft using data-driven machine learning

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能源与人工智能(英文) 2023年第2期12卷 145-162页

作者： Mihaela Mitici Birgitte Hennink Marilena pavel Jianning Dong Faculty of Science Utrecht UniversityHeidelberglaan 83584 CSUtrechtThe Netherlands Faculty of Aerospace Engineering Delft University of TechnologyKluyverweg 1HS 2926DelftThe Netherlands Electrical Engineering Mathematics and Computer Science FacultyTU Delft2628 CDDelftThe Netherlands

The health management of batteries is a key enabler for the adoption of Electric Vertical Take-off and Landingvehicles (eVTOLs). Currently, few studies consider the health management of eVTOL batteries. One distinctcharacteristic of batteries for eVTOLs is that the discharge rates are significantly larger during take-off andlanding, compared with the battery discharge rates needed for automotives. Such discharge protocols areexpected to impact the long-run health of batteries. This paper proposes a data-driven machine learningframework to estimate the state-of-health and remaining-useful-lifetime of eVTOL batteries under varying flightconditions and taking into account the entire flight profile of the eVTOLs. Three main features are consideredfor the assessment of the health of the batteries: charge, discharge and temperature. The importance of thesefeatures is also quantified. Considering battery charging before flight, a selection of missions for state-ofhealth and remaining-useful-lifetime prediction is performed. The results show that indeed, discharge-relatedfeatures have the highest importance when predicting battery state-of-health and *** several machine learning algorithms, it is shown that the battery state-of-health and remaining-useful-lifeare well estimated using Random Forest regression and Extreme Gradient Boosting, respectively.

关键词： Electric Vertical Take-off and Landing vehicles Lithium-ion battery State-of-health Machine learning Remaining-useful-life

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Population genetic structure in the paddyfield warbler （Acrocephalus agricola Jerd.）

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Current Zoology 2011年第1期57卷 63-71页

作者： pavel ZEHTINDJIEV Mihaela ILIEVA Bengt HANSSON Olga OPARINA Mihail OPARIN Staffan BENSCH Institute of Biodiversity and Ecosystem Research Bulgarian Academy of Sciences 2 Gagarin Street 1113 Sofia Bulgaria Department of Ecology Lund University Ecology Building SE-223 62 Lund Sweden A.N.Severtsov Institute of Ecology and Evolution Russian Academy of Sciences Saratov Branch 410028 Rabochaya Str.24 Saratov Russia

Population genetic structure was studied in paddyfield warblers Acrocephalus agricola breeding in NE Bulgaria, SE Russia and S Kazakhstan. We were particularly interested in the degree of genetic differentiation and gene flow of the Bulgarian population due to its geographical isolation, recent origin and unique migratory strategy. Analyses of mitochondrial DNA （mtDNA） showed that there was no divergence between Bulgarian and Russian populations （FsT = 0.007）, whereas those in Ka- zakhstan differed significantly from the European breeding populations （Russia： FsT = 0.058; Bulgaria： FsT = 0.114）. The degree of differentiation between populations at nuclear markers （five microsatellite loci; FsT ~ 0） was weaker than for mtDNA. We suggest that this relatively weak differentiation over the range of this species reflects a recent postglacial expansion, and results from mismatch distribution analyses and Fu＇s Fs tests are in agreement. Preservation of small and geographically isolated popula- tions which may contain individuals with unique adaptive traits, such as the studied Bulgarian population of paddyfield warbler, is valuable for the long-term conservation of expanding migratory bird species

关键词： Phylogeography Post-glacial expansion Population structure Mitochondria Microsatellite

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Thermal state of ice-rich soils on the Tommot-Yakutsk Railroad right-of-way

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Research in Cold and Arid Regions 2014年第4期6卷 356-360页

作者： pavel Skryabin Melnikov Permafrost Institute Siberian Branch of the Russian Academy of SciencesYakutsk 677010 Russia

This paper summarizes the results of investigations carried out in the northern section of the Tommot-Yakutsk Railroad in eastern Siberia, underlain by ice-rich permafrost. The ongoing permafrost and geotechnical research program in support of railroad construction includes assessment of the ground thermal state on the right-of-way and adjacent areas based on long-term field observations using the method of terrain thermal physics. These studies focus on the upper permafrost within the depth of annual temperature variation. In undisturbed areas, inter-annual variability of the ground thermal state shows little response to recent climatic variations. However, forest clearing and surface disturbance during right-of-way construction cause an increase in permafrost temperature, deepening of the active layer, thaw settlement, and water accumulation along the embankment. The active layer is thickest along the sun-exposed left berm and is thinnest along the more shaded right berm. Measures to prevent thaw-related embankment problems are recommended.

关键词： railroad right-of-way temperature thaw depth dynamics permafrost

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The Research on User Profiling and Time Awareness-based Hybrid Approaches for Recommendation Systems

The Research on User Profiling and Time Awareness-based Hybr...

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作者： pavel Stakhiyevich 陕西师范大学

学位级别：硕士

当前,大多数互联网用户都面临着信息过载的问题。因此,学术界和工业界出现了各种推荐系统和方法来解决这一问题。推荐系统一般根据用户的个人信息库来预测用户对未知项目的评价或者为用户提供相关信息。混合推荐系统集成了不同的推荐方... 详细信息

当前,大多数互联网用户都面临着信息过载的问题。因此,学术界和工业界出现了各种推荐系统和方法来解决这一问题。推荐系统一般根据用户的个人信息库来预测用户对未知项目的评价或者为用户提供相关信息。混合推荐系统集成了不同的推荐方法和技术,利用它们各自的优点,克服它们各自的局限性,来获得更好的结果并提高预测和推荐的质量。然而,尽管推荐系统在工业界和学术界得到了广泛关注和快速发展,但它仍然面临着冷启动、数据稀疏、用户建模以及用户兴趣偏好转移等诸多挑战和限制。许多学术研究只关注用户与用户或者项目与用户之间的相似度算法,而忽略了用户个人信息库的重要性。此外,这些学术研究也没有给予用户兴趣的动态变化以足够的关注。因此,除了提高推荐结果的准确性外,还可以通过解决推荐系统的这些挑战和局限性,进一步提高推荐的效率和有效性。本文主要聚焦于用户建模和混合推荐方法,研究了不同的用户建模方法以解决在推荐系统中遇到的诸多挑战和缓解推荐系统的局限性。此外,用户生成的内容（如用户评论）也被用于用户建模,以改善用户个人信息库和提高推荐的性能。在用户建模研究的支持下,本文提出了一种新的用户混合推荐方法,该方法主要用来解决用户兴趣偏好变化问题和提高推荐的性能。本文所提出的混合推荐方法采用基于内容和神经协同过滤的方法,利用扩展的用户和项目信息执行用户建模、评分预测和Top N推荐任务。此外,该混合推荐系统还将扩展的用户和项目信息应用于知识图谱中,以利用用户、项目、属性和特征之间的关系来提高评分预测的性能。本文采用准确率、召回率、新颖性、多样性、MAE（Mean Absolute Error）和RMSE（Root Mean Square Error）等多种评价指标,把该混合推荐方法与几种基准推荐算法进行了全面地,详细地评估和比较。实验结果表明,本文提出的混合推荐方法解决了用户兴趣偏好变化的问题,而且在评分预测以及Top N推荐上优于目前这些基准方法。此外,本文还设计并实现了一个基于该推荐方法的推荐系统原型。该推荐系统原型提供了其管理的图形用户界面以及允许用户查看、执行和控制本文提出功能,此外,原型还包括查看和搜索系统中所有的用户和项目,构建和查看不同的知识图谱,为每个用户创建其个人信息库,生成评分预测以及Top N推荐。本研究有助于学术界在用户建模,混合推荐方法和推荐系统评估等方面的研究。而且,基于本文提出的混合推荐方法,本研究设计和开发了一个推荐系统原型,促进了推荐系统行业的发展。

关键词：混合推荐用户建模用户信息知识图推荐系统原型

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Etiology and functional status of liver cirrhosis by ^(31)P MR spectroscopy

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World Journal of Gastroenterology 2005年第44期11卷 6926-6931页

作者： Monika Dezortova pavel Taimr Antonin Skoch Julius Spicak Milan Hajek MR Unit Institute for Clinical and Experimental Medicine Prague Czech Republic Department of Hepatogastroenterology Institute for Clinical and Experimental Medicine

AIM: To assess the functional status and etiology of liver cirrhosis by quantitative 31p magnetic resonance spectroscopy (MRS).METHODS: A total of 80 patients with liver cirrhosis of different etiology and functional status described by Child-Pugh score were examined and compared to 11 healthy volunteers. MR examination was performed on a 1.5 T imager using a 1H/31P surface coil by the 2D chemical shift imaging *** concentrations of phosphomonoesters (PME),phosphodiesters (PDE), inorganic phosphate (Pi) and adenosine triphosphate (ATP) were ***: MRS changes reflected the degree of liver dysfunction in all the patients as well as in individual etiological groups. The most important change was a decrease of PDE. It was possible to distinguish alcoholic,viral and cholestatic etiologies based on MR *** and viral etiology differed in PDE (alcoholic,viral, controls: 6.5±2.3, 6.5±3.1, 10.8±2.7 mmol/L,P＜0.001) and ATP (alcoholic, viral, controls: 2.9±0.8, 2.8±0.9, 3.7±1.0 mmol/L, P＜0.01) from the control *** viral etiology, patients with alcoholic etiology also differed in Pi (alcoholic, controls: 1.2±0.4, 1.6±0.6mmol/L, P＜0.05) from controls. No significant changes were found in patients with cholestatic disease and controls; nevertheless, this group differed from both alcoholic and viral groups (cholestatic, alcoholic, viral: 9.4±2.7, 6.5±2.3, 6.5±3.1 mmol/L, P＜0.005) in ***: 31p MRS can significantly help in noninvasive separation of different etiological groups leading to liver cirrhosis. In addition, MRS changes reflect functional liver injury.

关键词： Liver cirrhosis ^ 31p MR spectroscopy Absolute concentration Child-Pugh score Etiology

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Understanding livestock production and sustainability of grassland ecosystems in the Asian Dryland Belt

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Ecological Processes 2017年第1期6卷 225-234页

作者： Jiaguo Qi Xiaoping Xin Ranjeet John pavel Groisman Jiquan Chen Department of Geography Environmentand Spatial Sciences and Center for Global Change and Earth ObservationsMichigan State UniversityEast LansingMIUSA Chinese Academy of Agricultural Sciences BeijingChina University Corp.for Atmospheric Research NOAA National Centers for Environmental Information AshevilleNCUSA Zhejiang University HangzhouChina

Background:Companioned by economic development,a dietary shift toward higher meat consumption is seen in developing countries and transitional economies,where the demand for livestock production has been increasing in response to such a dietary *** the Asian Dryland Belt,approaches to meet this demand have focused on grazing intensification,cropland conversion for animal feed,and supplemental *** the scarcity of water,energy,and food in the region,a key question is whether or not the current approaches are *** not,what are the pathways to increase livestock production while protecting the region’s environment for a sustainable future?We provide our reviews and discuss current approaches in response to these dietary shifts and assess their environmental resilience with a focus on the grassland ecosystems in the Asian Dryland ***:While current approaches alleviate the urgent need for short-term livestock production,they lead to longterm vulnerability in food ***-offs between short gains and long-term losses,between food for humans and for animals,and between agricultural intensification and environmental degradation need to be holistically examined for the sustainable development of the region.A grassland water,energy,and food nexus framework is proposed with specific recommendations to increase livestock production while considering other ecosystem services of the dryland grassland ecosystems in the Asian Dryland ***:Current practices to increase livestock production are likely to lead to long-term,large-scale ecological degradation of the grassland ecosystems in the Asian Dryland Belt and are thus *** considering the trade-offs in the nexus of water,land,food,and livelihoods,sustainable pathways were articulated and *** pilot studies are needed for validation and adoption.

关键词： Dietary shift Livestock production Sustainability Grassland WEF nexus Drylands

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