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SPLITTING A CONCAVE DOMAIN TO CONVEX SUBDOMAINS

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Journal of Computational Mathematics 1998年第4期16卷 327-336页

作者： Li-ping Liu michal krizek(Mathematical Institute, Academy of Sciences, Zitna 25, CZ-11567 Prague 1, Czech Republic) Mathematical Institute Academy of Sciences 捷克斯洛伐克

We examine a steady-state heat radiation problem and its finite element approximation in Rd, d = 2, 3. A nonlinear Stefan-Boltzmann boundary condition is considered. Another nonlinearity is due to the fact that the temperature is always greater or equal than 0[K]. We prove two convergence theorems for piecewise linear finite element solutions.

关键词： Nonlinear elliptic boundary value problems, heat radiation problem finite elements variational inequalities

FINITE ELEMENT APPROXIMATION OF A NONLINEAR STEADY-STATE HEAT CONDUCTION PROBLEM

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Journal of Computational Mathematics 2001年第1期19卷 27-34页

作者： michal krizek (Mathematical Institute, Academy of Sciences, ■itn■ 25, CZ-115 67 Prague 1, Czech Republic) Mathematical Institute Academy of Sciences 捷克斯洛伐克 CZ-115 67

Examines a nonlinear partial differential equation of elliptic type with the homogeneous Dirichlet boundary conditions; Proof of the comparison and maximum principles; Approximation of the finite element; Introduction... 详细信息

关键词： Boundary value elliptic problems Comparison principle Maximum principle Finite element method Discrete maximum principle Nonobtuse partitions.

Antigravity—Its Manifestations and Origin

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International Journal of Astronomy and Astrophysics 2013年第3期3卷 227-235页

作者： michal krizek Lawrence Somer Institute of Mathematics Academy of SciencesPragueCzech Republic Department of Mathematics Catholic University of AmericaWashington DCUSA

Dark energy has been introduced in order to explain the observed acceleration of the expansion of our Universe. It seems to be distributed almost uniformly and it has an essential influence on the present value of the Hubble constant which characterizes the rate of this expansion. The Newtonian theory of gravitation is formulated so that the laws of conservation of energy and momentum hold. However, the Universe is designed so that the total amount of energy is slowly, but continually increasing, since its expansion is accelerating. Our examples show that even the Solar System and also our Galaxy imperceptibly expand thanks to dark energy whose origins are tiny antigravity forces. We claim that these forces appear due to the finite speed of gravitational interaction, which causes gravitational aberration effects. We show that effects of dark energy are observable;they are not only globally, but also in local systems. These effects can be measured and are comparable with the present value of the Hubble constant.

关键词： Hubble Parameter Dark Energy Antigravity Cosmological Constant Gravitational Aberration Conservation of Energy and Momentum Law Solar System

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有限元插值误差的下界估计

数学的实践与认识 2009年第15期39卷 159-164页

作者：陈蔚 michal krizek 山东大学经济学院山东济南250100 捷克科学院数学研究所捷克布拉格zitna25CZ-11567

基于一维区域上的拟一致剖分,证明了线性元插值误差的最优下界估计.基于此并利用超收敛理论,我们得到了有限元离散误差的上、下界.

关键词： Lagrange有限元 Cea's引理下界估计

Extracting multi-objective multigraph features for the shortest path cost prediction:Statistics-based or learning-based?

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Green Energy and Intelligent Transportation 2024年第1期3卷 1-15页

作者： Songwei Liu Xinwei Wang michal Weiszer Jun Chen School of Engineering and Materials Science Queen Mary University of LondonMile End RoadLondon E14NSUnited Kingdom

Efficient airport airside ground movement(AAGM)is key to successful operations of urban air *** studies have introduced the use of multi-objective multigraphs(MOMGs)as the conceptual prototype to formulate *** calculation of the shortest path costs is crucial for the algorithmic heuristic search on MOMGs,however,previous work chiefly focused on single-objective simple graphs(SOSGs),treated cost enquires as search problems,and failed to keep a low level of computational time and storage *** paper concentrates on the conceptual prototype MOMG,and investigates its node feature extraction,which lays the foundation for efficient prediction of shortest path *** extraction methods are implemented and compared:a statistics-based method that summarises 22 node physical patterns from graph theory principles,and a learning-based method that employs node embedding technique to encode graph structures into a discriminative vector *** former method can effectively evaluate the node physical patterns and reveals their individual importance for distance prediction,while the latter provides novel practices on processing multigraphs for node embedding algorithms that can merely handle *** regression models are applied to predict the shortest path costs to demonstrate the performance of *** experiments on randomly generated benchmark MOMGs show that(i)the statistics-based method underperforms on characterising small distance values due to severe overestimation;(ii)A subset of essential physical patterns can achieve comparable or slightly better prediction accuracy than that based on a complete set of patterns;and(iii)the learning-based method consistently outperforms the statistics-based method,while maintaining a competitive level of computational complexity.

关键词： Multi-objective multigraph Feature extraction Shortest path cost prediction Node patterns Node embeddings Regression

Inertial mixing of acoustically levitated droplets for time-lapse protein crystallography

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Droplet 2024年第3期3卷 91-101页

作者： Soichiro Tsujino Yohei Sato Shichao Jia michal W.Kepa Sofia Trampari Takashi Tomizaki Division of Biology and Chemistry Paul Scherrer InstitutVilligenSwitzerland Swiss Nanoscience Institute University of BaselBaselSwitzerland Division Scientific Computing Theory and DataPaul Scherrer InstitutVilligenSwitzerland Biozentrum University of BaselBaselSwitzerland Photon Science Division Paul Scherrer InstitutVilligenSwitzerland

Varying the chemical consistency of acoustically levitated droplets opens up an in situ study of chemical and biochemical reactions in small ***,the opti-mization of the mixing time and the minimization of the positional instability induced by solution dispensing are necessary for practical applications such as the study of the transient state of macromolecules crystallography during the ligand binding *** this purpose,we study the inertial mixing in a configuration compatible with the room-temperature crystallography using the acoustic levitation diffractometer,therein solution drops ejected at high velocity collide and coalesce with droplets dis-pensed on acoustically levitated and rotating polymer thin-film sample *** the proposed method,we are able to achieve the mixing time of∼0.1 s for sub-micro and a few microliter *** observed short mixing time is ascribed to the rapid penetration of the solution into the droplets and confirmed by a computational fluid dynamic *** demonstrated accelerated solution mixing is tested in a pilot time-lapse protein crystallography experiment using the acoustic levitation *** results indicate the detection of transient ligand binding state within 2 s after the solution dispensing,suggesting the feasibility of the proposed method for studying slow biochemical processes.

关键词： mixing droplets transient

Structural correlation and chemistry of molten NaF-ScF_(3) with dissolved metal aluminium:TG/DTA,XRD,NMR and molecular dynamics simulations

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Rare Metals 2024年第7期43卷 3356-3369页

作者： Aydar Rakhmatullin Frantisek Simko Didier Zanghi Zuzana Netriová Ilya BPolovov Ayrat Dimiev Konstantin V.Maksimtsev Catherine Bessada michal Korenko Conditions Extrêmes et Materiaux:Haute Température et Irradiation CEMHTIUPR 3079-CNRS Univ Orleans45071 OrleansFrance Department of Molten Systems Institute of Inorganic ChemistrySlovak Academy of Sciences84536 BratislavaSlovakia Centre of Excellence for Advanced Materials Application-CEMEA Slovak Academy of Sciences84511Bratislava.Slovakia Department of Rare Metals and Nanomaterials Institute of Physics and TechnologyUral Federal UniversityUral Federal University620002 EkaterinburgRussia Alexander Butlerov Institute of Chemistry Kazan Federal University420008KazanRussia

For the first time,the mechanism of metal aluminum dissolution in NaF-ScF_(3) eutectic melts and the chemical interaction between the constituents of this mixture have been thoroughly studied by a combination of differential thermal analysis(DTA),high temperature and solid-state nuclear magnetic resonance(NMR),and X-ray diffraction(XRD) coupled with the molecular dynamic *** formation of an insoluble Al_(3)Sc alloy in molten(NaF-ScF_(3))_(eut)system was proven,and the chemical mechanism of this aluminothermic Al_(3)Sc alloy production was *** ex situ examinations bring to light the formation of NaScF_4 and solid solution of Na_(3)(Al,Sc)F_(6) in cooled *** molecular dynamics calculations of the bath allow us to construct the structural model and to predict viscosity,density and electrical conductivity of the reagent melt to help to optimize the conditions of the alloy synthesis.

关键词： Scandium Alloy Molten salts NMR Molecular dynamics

Dormancy heterogeneity among Arabidopsis thaliana seeds is linked to individual seed size

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Plant Communications 2024年第2期5卷 215-227页

作者： michal Krzyszton Sebastian P.Sacharowski Veena Halale Manjunath Katarzyna Muter Grzegorz Bokota Ce Wang Dariusz Plewczynski Tereza Dobisova Szymon Swiezewski Laboratory of Seeds Molecular Biology Institute of Biochemistry and BiophysicsPAS02-106 WarsawPoland Laboratory of Functional and Structural Genomics Centre of New TechnologiesUniversity of WarsawWarsawPoland Laboratory of Bioinformatics and Computational Genomics Faculty of Mathematics and Information ScienceWarsaw University of TechnologyWarsawPoland Labdeers Ltd. 680-01 BoskoviceCzech Republic

Production of morphologically and physiologically variable seeds is an important strategy that helps plants to survive in unpredictable natural ***,the model plant Arabidopsis thaliana and most agronomically essential crops produce visually homogenous *** automated phenotype analysis,we observed that small seeds in Arabidopsis tend to have higher primary and secondary dormancy levels than large *** analysis revealed distinct gene expression profiles between large and small *** seeds have higher expression of translation-related genes implicated in germination *** contrast,small seeds have elevated expression of many positive regulators of dormancy,including a key regulator of this process,the DOG1 *** in DOG1 expression are associated with differential production of its alternative cleavage and polyadenylation isoforms;in small seeds,the proximal poly(A)site is selected,resulting in a short mRNA ***,single-seed RNA sequencing analysis demonstrated that large seeds resemble DOG1 knockout mutant ***,on the single-seed level,expression of genes affected by seed size is correlated with expression of genes that position seeds on the path toward *** results demonstrate an unexpected link between seed size and dormancy phenotypes in a species that produces highly homogenous seed pools,suggesting that the correlation between seed morphology and physiology is more widespread than initially assumed.

关键词： seed size dormancy DOG1 Arabidopsis

Sustaining forest biodiversity:Exploring the effect of long-term natural disturbance dynamics on contemporary lichen communities in primary forest ecosystems

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Forest Ecosystems 2024年第4期11卷 556-567页

作者： Rhiannon Gloor Marek Svitok Martin Mikolas Jenyk Hofmeister Josef Halda Pavel Janda Francesco Maria Sabatini Lucie Zemanova Arne Buechling Daniel Kozak Matej Ferencik michal Frankovic Martin Dusatko Miroslav Svoboda Department of Forest Ecology Faculty of Forestry and Wood SciencesCzech University of Life Sciences PragueKamycka 129Praha 6–Suchdol16500Czech Republic Faculty of Ecology and Environmental Sciences Technical University in ZvolenT.G.Masaryka 2496001ZvolenSlovakia Institute of Botany Plant Science and Biodiversity CenterSlovak Academy of SciencesDúbravska cesta 984523BratislavaSlovakia PRALES Odtrnovie 56301322RosinaSlovakia Faculty of Science University of Hradec KraloveHradecka 1285Hradec KraloveⅢ50003Czech Republic BIOME–Biogeography and Macroecology Department of BiologicalGeological and Environmental Sciences(BIGEA)Alma Mater Studiorum-University of Bolognavia Irnerio 42BolognaItaly

In this era of biodiversity loss and climate change,quantifying the impacts of natural disturbance on forest communities is imperative to improve biodiversity conservation *** and epixylic lichens are effective forest quality bioindicators,as they are generally long-lived organisms supported by continuity of specific forest structures and their associated microclimatic ***,how lichen communities respond to the effects of fluctuating historical disturbances remains *** a dendrochronological approach,this study investigates how natural disturbance dynamics indirectly influence various lichen community metrics in some of Europe's best-preserved primary mixed-beech *** modelling revealed that natural historical disturbance processes have decades-long effects on forest structural attributes,which had both congruent and divergent impacts on lichen community richness and *** species richness indirectly benefited from both historical and recent higher-severity disturbances via increased standing dead tree basal area and canopy openness respectively-likely through the presence of both pioneer and late-successional species associated with these ***-listed species richness showed a dependence on habitat continuity(old trees),and increased with disturbance-related structures(standing dead trees)whilst simultaneously benefiting from periods without severe disturbance events(old trees and reduced deadwood volume).However,if the disturbance occurred over a century in the past,no substantial effect on forest structure was ***,while disturbance-mediated forest structures can promote overall richness,threatened species appear vulnerable to more severe disturbance events-a concern,as disturbances are predicted to intensify with climate ***,the high number of threatened species found reinforce the critical role of primary forest structural attributes for biodiversity ***

关键词： Mixed-beech forests Species richness Old-growth forests Carpathian mountains Biodiversity conservation Dendroecology Fagus sylvatica