检索结果-南通市图书馆

Trapped on the Roof of the World:taxonomic diversity and evolutionary patterns of Tibetan Plateau endemic freshwater snails(Gastropoda:Lymnaeidae:Tibetoradix)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2022年第5期17卷 825-848页

作者： maxim v.vinarski Parm viktor vON OHEIMB Olga v.AKSENOvA Mikhail Yu.GOFAROv Alexander v.KONDAKOv Ivan O.NEKHAEv Ivan N.BOLOTOv Laboratory of Macroecology and Biogeography Saint-Petersburg State UniversitySaint-PetersburgRussia Museum für Naturkunde-Leibniz Institute for Evolution and Biodiversity Science BerlinGermany N.Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences ArkhangelskRussia Department of Applied Ecology Saint-Petersburg State UniversitySaint-PetersburgRussia Northern(Arctic)Federal University ArkhangelskRussia

The high-elevation Tibetan Plateau(western China)is inhabited by a unique,though not particularly species-rich,community of *** explored the species content and evolutionary history of the Tibetan Plateau endemic freshwater snail genus *** relationships within the genus were reconstructed based on available sequence *** used a single-rate Poisson Tree Processes approach for species delimitation and compared putative species-level clades with already described *** found that the genus consists of at least 6 species,of which we described 4 as new to *** and soft body morphology was examined and the radula in Tibetoradix was described for theﬁrst *** on ourﬁndings,the diversiﬁcation of the genus did not result in a prominent morphological differentiation and a number of species can be regarded as morphologically *** species found in different drainage areas indicate relatively good passive dispersal abilities of the *** allopatric distribution of the species could result from competitive exclusion between *** absence of Tibetoradix *** the Tibetan Plateau could be explained by a scenario of an“evolutionary trap”,where adaptations to high elevation conditions prevented the taxa from a successful colonization of lower elevations.

关键词： biogeography High Asia molecular phylogenetics morphology species delimitation

Elucidating elusive quaternary selenide EuCeCuSe3:Synthesis,crystal structure,properties and theoretical studies

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 Rare Earths 2024年第1期42卷 163-171,I0006页

作者： maxim v.Grigoriev Anna v.Ruseikina maxim S.Molokeev vladimir A.Chernyshev Aleksandr S.Aleksandrovsky Alexander S.Krylov Svetlana N.Krylova Nikolai P.Shestakov Dmitriy A.velikanov Alexander A.Garmonov Alexey v.Matigorov Evgeny A.Ostapchuk Thomas Schleid Damir A.Safin Laboratory of Theory and Optimization of Chemical and Technological Processes University of TyumenVolodarskogo Str.6625003TyumenRussian Federation Kirensky Institute of Physics Federal Research Center KSC SB RASAkademgorodok 50 Bld.38660036KrasnoyarskRussian Federation Department of Physics Far Eastern State Transport UniversitySerysheva Str.47680021KrasnoyarskRussian Federation Institute of Natural Sciences and Mathematics Ural Federal University Named After the First President of Russia B.N.YeltsinMira Str.19620002EkaterinburgRussian Federation Department of Photonics and Laser Technology Siberian Federal UniversitySvobodnii Ave.79660079KrasnoyarskRussian Federation Institute of Physics and Technology University of TyumenVolodarskogo Str.6625003 TyumenRussian Federation Institute for Inorganic Chemistry University of StuttgartPfaffenwaldring 55D-70569StuttgartGermany Scientific and Educational and Innovation Center for Chemical and Pharmaceutical Technologies Ural Federal University named after the First President of Russia B.N.YeltsinMira Str.19620002 EkaterinburgRussian Federation University of Tyumen Volodarskogo Str.6625003TyumenRussian Federation

We report on the novel heterometallic quaternary selenide EuCeCuSe3,the fabrication of which has been a challenge until this *** structure of the reported selenide was elucidated from the powder X-ray diffraction data,which revealed the formation of EuCeCuSe3with excellent yield(96.7%)accompanied with a minor fraction of CeSe2(3.3%),and was best solved in orthorhombic space group Pnma with the BaLaCuS3structural ***,the crystal structure of the title compound completes the row of the heterometallic quaternary selenides EuRECuSe3(RE=La,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y),of which the cerium-based derivative exclusively belongs to the BaLaCuS3structural *** distortion of the CuSe4polyhedron was compared for the whole series of EuRECuSe3compounds using theτ4-descriptor for four coordinated ions,which revealed the highest degree of distortion for the Ce3+-containing selenide,followed by the La3+-based ***,the crystallographic and geometrical parameters of the reported selenide were discussed in comparison to the Ce3+-based sulfides SrCeCuS3and *** initio calculations of the crystal structure,a phonon spectrum and elastic constants for the crystal of EuCeCuSe3were also *** types and wavenumbers of fundame ntal modes were determined and the involvement of ions participating in the phonon modes was *** experimental IR spectrum of the reported selenide was interpreted and found to be in agreement with the calculated *** experimental direct band gap of EuCeCuSe3was measured to be 1.36 ev that is consistent with the concept of its origin due to interband transitions between orbitals emerging mainly from 4f(valence band)and 5d(conduction band)levels of the Eu2+*** dependence of the Young’s modulus on the direction demonstrates the anisotropy of the elastic properties,while the vickers hardness for EuCeCuSe3was calculated to be 5.2 ***,the title compound is paramagnetic above 4 K.

关键词： Quaternary selenide Synthesis Crystal structure Ab initio calculations Magnetic measurements Spectroscopy

Expanded Porphyrin Exhibiting Off-Centered Out-of-Plane Coordination to Dysprosium

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2024年第7期6卷 1731-1738页

作者： Dmitry I.Nazarov Jorge Labella Alexey v.Kuzmin maxim A.Faraonov Evgenii N.Ivanov Salavat S.Khasanov Tomas Torres Mikhail K.Islyaikin Dmitri v.Konarev Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry RAS 142432 Chernogolovka Department of Organic Chemistry Universidad Autonoma de Madrid28049 Madrid Institute of Solid-State Physics RAS 142432 Chernogolovka Research Institute of Macroheterocycles Ivanovo State University of Chemistry and Technology15300 Ivanovo G.A.Krestov Institute of Solution Chemistry of the Russian Academy of Sciences 153045 Ivanovo Institute for Advanced Research in Chemical Sciences Universidad Autonoma de Madrid28049 Madrid IMDEA-Nanociencia 28049 Madrid

The complexation of high-spin lanthanides to porphyrinoids is a powerful strategy for the development of advanced molecular *** this context,the use of expanded porphyrinoids remains elusive since their coordination chemistry is challenging to ***,taking inspiration from on-surface chemistry,we explored the coordination of Dy^(3+)to a six-membered porphyrinoid,namely,the hemihexaphyrazine ***,we observed the selective formation of a mono-nuclear off-centered,out-of-plane H_(2)Hhp-Dy^(3+)complex when performing the complexation under reductive *** this reaction,the oxidation state of the macrocycle did not *** X-ray diffraction analysis,we found that the coordination number of Dy in this complex was *** macrocycle cocrystallized with decamethylcobaltocene(Cp_(2)^(*)Co)molecules,giving rise to a wellordered solid-state packing,governed byπ-π*** a result of this organization,a small magnetic coupling between the neighboring molecules was *** in all,this work provides key insights into the coordination of magnetically active metals with expanded porphyrinoids,thus motivating the development of advanced spintronic devices.

关键词： porphyrins dysprosium macrocycle coordination chemistry magnetism

Nonlinear Rydberg exciton-polaritons in Cu2O microcavities

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第4期13卷 619-627页

作者： maxim Makhonin Anthonin Delphan Kok Wee Song Paul Walker Tommi Isoniemi Peter Claronino Konstantinos Orfanakis Sai Kiran Rajendran Hamid Ohadi Julian Heckötter Marc Assmann Manfred Bayer Alexander Tartakovskii Maurice Skolnick Oleksandr Kyriienko Dmitry Krizhanovskii Department of Physics and Astronomy University of SheffieldSheffield S37RHUK. Department of Physics and Astronomy University of ExeterStocker RoadExeter EX44PYUK. SUPA School of Physics and AstronomyUniversity of St AndrewsSt Andrews KY169SSUK. Fakultät Physik TU DortmundAugust-Schmidt-Straße 444227 DortmundGermany

Rydberg excitons(analogues of Rydberg atoms in condensed matter systems)are highly excited bound electron-hole states with large Bohr *** interaction between them as well as exciton coupling to light may lead to strong optical nonlinearity,with applications in sensing and quantum information ***,we achieve strong effective photon–photon interactions(Kerr-like optical nonlinearity)via the Rydberg blockade phenomenon and the hybridisation of excitons and photons forming polaritons in a Cu2O-filled *** pulsed resonant excitation polariton resonance frequencies are renormalised due to the reduction of the photon-exciton coupling with increasing exciton *** analysis shows that the Rydberg blockade plays a major role in the experimentally observed scaling of the polariton nonlinearity coefficient as∝n4.4±1.8 for principal quantum numbers up to n=*** high principal quantum numbers studied in a polariton system for the first time are essential for realisation of high Rydberg optical nonlinearities,which paves the way towards quantum optical applications and fundamental studies of strongly correlated photonic(polaritonic)states in a solid state system.

关键词： density Rydberg polar

Learning surface molecular structures via machine vision

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2017年第1期3卷 194-202页

作者： maxim Ziatdinov Artem Maksov Sergei v.Kalinin Institute for Functional Imaging of Materials Oak Ridge National LaboratoryOak RidgeTN 37831USA Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA Bredesen Center for Interdisciplinary Research University of TennesseeKnoxvilleTN 37996USA

Recent advances in high resolution scanning transmission electron and scanning probe microscopies have allowed researchers to perform measurements of materials structural parameters and functional properties in real space with a picometre *** many technologically relevant atomic and/or molecular systems,however,the information of interest is distributed spatially in a non-uniform manner and may have a complex multi-dimensional *** of the critical issues,therefore,lies in being able to accurately identify(‘read out’)all the individual building blocks in different atomic/molecular architectures,as well as more complex patterns that these blocks may form,on a scale of hundreds and thousands of individual atomic/molecular *** we employ machine vision to read and recognize complex molecular assemblies on ***,we combine Markov random field model and convolutional neural networks to classify structural and rotational states of all individual building blocks in molecular assembly on the metallic surface visualized in high-resolution scanning tunneling microscopy *** show how the obtained full decoding of the system allows us to directly construct a pair density function—a centerpiece in analysis of disorderproperty relationship paradigm—as well as to analyze spatial correlations between multiple order parameters at the nanoscale,and elucidate reaction pathway involving molecular conformation *** method represents a significant shift in our way of analyzing atomic and/or molecular resolved microscopic images and can be applied to variety of other microscopic measurements of structural,electronic,and magnetic orders in different condensed matter systems.

关键词： allowed classify spatially

Off-the-shelf deep learning is not enough,and requires parsimony,Bayesianity,and causality

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 133-138页

作者： Rama K.vasudevan maxim Ziatdinov Lukas vlcek Sergei.v.Kalinin Center for Nanophase Materials Sciences Oak RidgeTN 37831USA Computational Sciences and Engineering Division Oak RidgeTN 37831USA Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Present address:Bayer St.LouisMO 63141USA

Deep neural networks(‘deep learning’)have emerged as a technology of choice to tackle problems in speech recognition,computer vision,finance,***,adoption of deep learning in physical domains brings substantial challenges stemming from the correlative nature of deep learning methods compared to the causal,hypothesis driven nature of modern *** argue that the broad adoption of Bayesian methods incorporating prior knowledge,development of solutions with incorporated physical constraints and parsimonious structural descriptors and generative models,and ultimately adoption of causal models,offers a path forward for fundamental and applied research.

关键词： learning enough finance

On the primitive divisors of the recurrent sequence un＋1=(4cos^2(2π/7)-1)un-un-1 with applications to group theory

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2018年第11期61卷 2101-2110页

作者： maxim vsemirnov St. Petersburg Department of v.A. Steklov Institute of Mathematics St. Petersburg 191023 Russia Department of Mathematics and Mechanics St. Petersburg State University St. Petersburg 198504 Russia

Consider the sequence of algebraic integers un given by the starting values u0=0,u1=1 and the recurrence u_(n+1)=(4cos^2(2π/7)-1)u_n-u_(n-1).We prove that for any n ■{1,2,3,5,8,12,18,28,30}the n-th term of the sequence has a primitive divisor in Z[2 cos(2π/7)].As a consequence we deduce that for any sufficiently large n there exists a prime power q such that the groupcan be generated by a pair x,y with χ~2=y^3=(xy)~7=1 and the order of the commutator[x,y]is exactly *** latter result answers in affirmative a question of Holt and Plesken.

关键词： recurrent sequences primitive divisors Hurwitz groups

Ensemble learning-iterative training machine learning for uncertainty quantification and automated experiment in atom-resolved microscopy

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 909-916页

作者： Ayana Ghosh Bobby G.Sumpter Ondrej Dyck Sergei v.Kalinin maxim Ziatdinov Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTNUSA Computational Sciences and Engineering Division Oak Ridge National LaboratoryOak RidgeTNUSA

Deep learning has emerged as a technique of choice for rapid feature extraction across imaging disciplines,allowing rapid conversion of the data streams to spatial or spatiotemporal arrays of features of ***,applications of deep learning in experimental domains are often limited by the out-of-distribution drift between the experiments,where the network trained for one set of imaging conditions becomes sub-optimal for different *** limitation is particularly stringent in the quest to have an automated experiment setting,where retraining or transfer learning becomes impractical due to the need for human intervention and associated *** we explore the reproducibility of deep learning for feature extraction in atom-resolved electron microscopy and introduce workflows based on ensemble learning and iterative training to greatly improve feature *** approach allows incorporating uncertainty quantification into the deep learning analysis and also enables rapid automated experimental workflows where retraining of the network to compensate for out-of-distribution drift due to subtle change in imaging conditions is substituted for human operator or programmatic selection of networks from the *** methodology can be further applied to machine learning workflows in other imaging areas including optical and chemical imaging.

关键词： learning experiment enable

Gaussian process analysis of electron energy loss spectroscopy data:multivariate reconstruction and kernel control

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 1395-1404页

作者： Sergei v.Kalinin Andrew R.Lupini Rama K.vasudevan maxim Ziatdinov Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTNUSA

Advances in hyperspectral imaging including electron energy loss spectroscopy bring forth the challenges of exploratory and physics-based analysis of multidimensional data *** multivariate linear unmixing methods generally explore similarities in the energy dimension,but ignore correlations in the spatial *** the same time,Gaussian process(GP)explicitly incorporate spatial correlations in the form of kernel functions but is computationally ***,we implement a GP method operating on the full spatial domain and reduced representations in the energy *** this multivariate GP,the information between the components is shared via a common spatial kernel structure,while allowing for variability in the relative noise magnitude or image *** explore the role of kernel constraints on the quality of the reconstruction,and suggest an approach for estimating them from the experimental *** further show that spatial information contained in higher-order components can be reconstructed and spatially localized.

关键词： domain kernel multivariate