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Heterogeneous LBM Simulation Code with LRnLA Algorithms

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Communications in Computational Physics 2023年第1期33卷 214-244页

作者： Vadim levchenko Anastasia Perepelkina Keldysh Institute of Applied Mathematics RAS

A design of a new heterogeneous code for LBM simulations is *** heterogeneous computing wemean a collaborative computation on CPU and GPU,which is characterized by the following features:the data is distributed between CPU and GPU memory spaces taking advantage of both parallel hierarchies;the capabilities of both SIMT GPU and SIMD GPU parallelization are used for calculations;the algorithms in use efficiently conceal the CPU-GPU data exchange;the subdivision of the computing task is performed with an account for the strong points of both processing units:high performance of GPU,low latency,and advanced memory hierarchy of *** code is a continuation of our work in the development of LRnLA codes for *** LRnLA codes had good efficiency both for CPU and GPU computing,and allowed GPU simulation performed on data stored in CPU RAM without performance loss on CPU-GPU data *** the new code,we use methods and instruments that can be flexibly adapted to GPU and CPU instruction *** present the theoretical study of the performance of the proposed code and suggest implementation *** bottlenecks are *** a result,we conclude that larger problems can be simulated with higher efficiency in the heterogeneous system.

关键词： LBM Roofline memory-bound GPU LRnLA

Prediction of Moments in the Particles on Demand Method for LBM

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Communications in Computational Physics 2023年第1期33卷 144-173页

作者： Elizaveta Zipunova Anastasia Perepelkina Vadim levchenko German Zvezdin Keldysh Institute of Applied Mathematics RAS 4 Miusskaya sq.MoscowRussia125047 Moscow State University 1 Ulitsa KolmogorovaMoscowRussia119991

PonD is a method to extend LBM calculations to arbitrary ranges of Mach number and *** current work was motivated by the issue of mass,momentum and energy conservation in the PonD method for *** collision guarantees their conservation,thus,the study involves all aspects of the streaming step:both coordinate and velocity space discretizations,gauge transfer method,resolution of the scheme *** obtaining the expressions for the change of moments in the system in a time update of the scheme,it was found that the scheme can be formulated as explicit in some ***,we found the sufficient conditions to make Pond/RegPonD computations explicit and mass,momentum,and energy *** scheme was implemented in the explicit form,and validated for several test cases.

关键词： LBM compressible off-grid

Low-Energy Driven Ring-Opening Behavior of Benzocyclobutene Derivatives

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Chinese Journal of Chemistry 2023年第23期41卷 3238-3244页

作者： Ziwei Yuan Quan Sun Jinchong Xiao Pingxia Zhang Konstantin S.levchenko Dmitry Y.Demin Wenxin Fu Laboratory of Science and Technology on High-Tech Polymer Materials Institute of ChemistryChinese Academy of SciencesBeijing100190 China College of Chemistry and Material Science Hebei UniversityBaodingHebei071002 China University of Chinese Academy of Sciences Beijing100049 China MIREA — Russian Technological University Moscow119454 Russian Federation

It's urgent to develop benzocyclobutene(BCB)-based polymers with low curing temperature for temperature-sensitive applications such as liquid crystal displays(LCDs)and flexible ***,the effect of substituents on the ring-opening behavior of BCB derivatives was *** ring-opening activation energy barriers(ΔGA)of BCB derivatives with one or two substituents on the four-membered alkyl ring were systematically calculated using the B3LYP *** mono-and di-substituted BCBs adopted the conrotatory ring-opening process,obeying the Woodward-Hoffmann's Rules upon *** mono-/di-substituted BCBs exhibited 8.2%—69%lowerΔGA compared with BCB,attributed to the electronic effects of the *** BCBs with both electron-donating and electron-withdrawing groups,e.g.,1-NH_(2)-8-NO_(2)-BCB,demonstrated the lowestΔ*** addition,BCB derivatives with amide/ester/acyloxy group modified on C1 position were synthesized as model molecules,and their ring-opening temperature can be decreased by 20℃ compared to the unsubstituted one,also consistent with our calculation *** work combined theoretical calculation methods with experimental results to provide valuable insights into the design and synthesis of BCB derivatives and next-generation BCB functional packaging materials with low ring-opening temperature.

关键词： Benzocyclobutene Thermosets Monomers Low curing temperature Activation energy barrier Electronic effect Captodative effect

Enhanced xylene sensing performance of hierarchical flower-like Co_(3)O_(4) via In doping

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Chinese Physics B 2023年第6期32卷 644-651页

作者：张京凌剑宇谷魁坤 Georgiy G.levchenko 梁霄 State Key Laboratory of Superhard Materials Physics of CollegeJilin UniversityChangchun 130012China Institute for Interdisciplinary Biomass Functional Materials Studies Jilin Provincial Key Laboratory of Straw-Based Functional MaterialsJilin Engineering Normal UniversityChangchun 130052China Donetsk Institute for Physics and Engineering named after O.O.Galkin NAS of UkraineKyiv 03028Ukraine

Metal ions doping is a typical approach for tuning sensing properties of metal oxide semiconductors based gas ***,hierarchical flower-like pure and In-doped Co_(3)O_(4) nanostructures assembled by porous two-dimensional(2D)nanosheets are synthesized via a solvothermal method and annealing *** sensing measurements display that the In@Co_(3)O_(4)-4 based sensor possesses high response value of 55.9 toward 100 ppm xylene at 150 ℃,which is nearly 3.8times larger than that of pure Co_(3)O_(4) ***,it possesses good selectivity and anti-humidity *** with the results of DFT calculations,the mechanism of enhanced gas sensing performance is analyzed systematically.

关键词： sensor Co_(3)O_(4) xylene density functional theory(DFT)

Fluorescence lifetime imaging for studying DNA compaction and gene activities

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Light(Science & Applications) 2021年第12期10卷 2349-2359页

作者： Svitlana M.levchenko Artem Pliss Xiao Peng Paras N.Prasad Junle Qu Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhenGuangdong 518060China Department of Cell Biophysics Faculty of BiochemistryBiophysics and BiotechnologyJagiellonian University30-387 KrakowPoland Institute for Lasers Photonics and BiophotonicsUniversity at BuffaloState University of New YorkBuffaloNY 14260-3000USA

Optical imaging is a most useful and widespread technique for the investigation of the structure and function of the cellular ***,an analysis of immensely convoluted and irregularly compacted DNA polymer is highly challenging even by modern super-resolution microscopy *** we propose fluorescence lifetime imaging(FLIM)for the advancement of studies of genomic structure including DNA compaction,replication as well as monitoring of gene *** proposed FLIM assay employs two independent mechanisms for DNA compaction *** mechanism relies on the inverse quadratic relation between the fluorescence lifetimes of fluorescence probes incorporated into DNA and their local refractive index,variable due to DNA compaction *** mechanism is based on the Förster resonance energy transfer(FRET)process between the donor and the acceptor fluorophores,both incorporated into *** these proposed mechanisms were validated in cultured *** obtained data unravel a significant difference in compaction of the gene-rich and gene-poor pools of genomic *** show that the gene-rich DNA is loosely compacted compared to the dense DNA domains devoid of active genes.

关键词： expression. lifetime donor

Entropy and equilibrium property of QCD-instanton induced final state in deep-inelastic scattering

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Chinese Physics C 2008年第1期32卷 13-17页

作者：邓为炳陆丁张纪英许明梅 Boris levchenko 刘连寿 Training Base for Research and Teaching in Fundamental Sciences(Physics)College of Physical Science and Technology Huazhong Normal University Institute of Particle Physics Huazhong Normal University Skobeltsyn Institute of Nuclear Physics Moscow State University 119992 MoscowRussia

The scaling and additivity properties of Rényi entropy in rapidity space of the instanton final state （IFS） and current jet identified by the r-sorting method from the QCDINS Monte Carlo event sample are studied. Asymptotic scaling of the Rényi entropy H2 is observed for the IFS while H2 for the current jet jtends to saturation with decreasing phase space scale. Furthermore, it is found that the additivity of H2 holds well for the IFS in narrow rapidity windows at different positions. These results indicate that the IFS produced in the instanton-induced process of deep inelastic scattering has reached local equilibrium.

关键词： instanton quark-gluon fusion deep-inelastic scattering entropy local equilibrium

Experience in the Production of Horizontal Ingots of Platinum Metals and Alloys

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贵金属 2012年第A1期33卷 250-252页

作者： levchenko S. D. VERSHININA E. N. OJSC "SIC 'Supermetal'" Moscow Russia.

The quality of semi-products of platinum metals and alloys, produced by way of plastic working, essentially depends on or, in many cases, is completely determined by the quality of ingots. Plastic working does not make it possible to eliminate or localize metallurgical defects. In many cases it promotes the occurence thereof. Low-rate casting with directional crystallization can ensure the production of dense ingots free of non-metallic inclusions, shrinkage and gas weakness, with observance of certain temperature/rate modes. After comparative tests of vertical and horizontal molds, preference has been given to horizontal water-cooled molds, allowing to cast all alloys in the conditions of directional crystallization.

关键词： ingot directional crystallization low-rate casting mold crystallization front metallurgical defect sticking pyrometallurgical refining

Towards efficient data exchange and sharing for big-data driven materials science:metadata and data formats

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npj Computational Materials 2017年第1期3卷 70-78页

作者： Luca M.Ghiringhelli Christian Carbogno Sergey levchenko Fawzi Mohamed Georg Huhs Martin Luders Micael Oliveira Matthias Scheffler Fritz Haber Institute of the Max Planck Society BerlinGermany Barcelona Supercomputing Center BarcelonaSpain Humboldt-Universitat zu Berlin BerlinGermany Daresbury Laboratory WarringtonUK University of Liege LiegeBelgium Max Planck Institute for the Structure and Dynamics of Matter HamburgGermany Department of Chemistry and Biochemistry and Materials Department University of California-Santa BarbaraSanta BarbaraCA 93106-5050USA

With big-data driven materials research,the new paradigm of materials science,sharing and wide accessibility of data are becoming crucial ***,a prerequisite for data exchange and big-data analytics is standardization,which means using consistent and unique conventions for,e.g.,units,zero base lines,and file *** are two main strategies to achieve this *** accepts the heterogeneous nature of the community,which comprises scientists from physics,chemistry,bio-physics,and materials science,by complying with the diverse ecosystem of computer codes and thus develops“converters”for the input and output files of all important *** converters then translate the data of each code into a standardized,codeindependent *** other strategy is to provide standardized open libraries that code developers can adopt for shaping their inputs,outputs,and restart files,directly into the same code-independent *** this perspective paper,we present both strategies and argue that they can and should be regarded as complementary,if not even *** represented appropriate format and conventions were agreed upon by two teams,the Electronic Structure Library(ESL)of the European Center for Atomic and Molecular Computations(CECAM)and the NOvel MAterials Discovery(NOMAD)Laboratory,a European Centre of Excellence(CoE).A key element of this work is the definition of hierarchical metadata describing state-of-the-art electronic-structure calculations.

关键词： metadata exchange translate

Graphene Flakes in Arc Plasma: Conditions for the Fast Single-Layer Growth

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Graphene 2016年第2期5卷 81-89页

作者： Igor levchenko Uroš Cvelbar Michael Keidar School of Chemistry Physics and Mechanical Engineering Queensland University of Technology Brisbane Australia Jozef Stefan Institute Ljubljana Slovenia George Washington University Washington DC USA

The results of systematic numerical studies of graphene flakes growth in low-temperature arc discharge plasmas are presented. Diffusion-based growth model was developed, verified using the previously published experiments, and used to investigate the principal effects of the process parameters such as plasma density, electron temperature, surface temperature and time of growth on the size and structure of the plasma-grown graphene flakes. It was demonstrated that the higher growth temperatures result in larger graphene flakes reaching 5 μm, and simultaneously, lead to much lower density of the carbon atoms adsorbed on the flake surface. The low density of the carbon adatoms reduces the probability of the additional graphene layer nucleation on surface of growing flake, thus eventually resulting in the synthesis of the most valuable single-layered graphenes.

关键词： Graphene Flakes Arc Plasma Growth Few-Layer Graphene