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Journal of Forestry Research 2020年第3期31卷 819-826页

作者： Marie Bartakova Eva Dvorackova Lucie Chromcova petr Hrdlicka Department of Chemistry and Biochemistry Mendel University in BrnoZemedelska 161300 BrnoCzech Republic

A comprehensive experimental design was developed to determine suitable conditions(volume, percentage of solvent, extraction temperature) for the ethanol extraction of phenolic compounds from ten tropical woody plants. Wenge, angelim vermelho, zebrano, merbau,tigerwood, angelim pedra, jatoba, angelim amargoso,massaranduba, and doussie woods were used in experiments. The effects of three independent variables and their interactions on the yields of cinnamic and benzoic acid derivates were analyzed using UHPLC-PDA. The most significant parameters were found to be solvent percentage,extraction volume, and extraction temperature. Optimal conditions for the extraction of phenolic compound contents were an 80℃ extraction temperature, a 30 mL extraction volume, and the use of pure water as the extraction solvent. The tested species of woods contained mainly cinnamic acid derivates. Water extracts after hydrolysis contained greater amounts of cinnamic acid derivates than those extracts from non-hydrolyzed *** total phenolics content was highest in water extracts of tigerwood, wenge and merbau;however, the extract of merbau wood was a stronger radical scavenger in ABTS?áassays: 34.11 ± 0.02 mM Trolox equivalents per g of dry extract. The main compounds possessing antioxidant activity in the extracts of vermelho wood assessed by UHPLC analysis were hydroxycinnamic acids.

关键词： Phenolic compounds Tropical woods Ultrahigh-performance liquid chromatography Antioxidant capacity

Numerical modeling of destress blasting for strata separation

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第9期15卷 2238-2249页

作者： petr Konicek Tuo Chen Hani S.Mitri Institute of Geonics Czech Academy of SciencesOstrava70800Czech Republic Department of Mining and Materials Engineering McGill UniversityMontrealH3A 0E8Canada

Destress blasting(DB)implemented along the perimeter of safety pillars is a special application of destressing in coal longwall *** goal is to separate relatively more deformed mined areas from safety pillars,such as shaft pillars or cross-cut pillars,to reduce the transfer of high stresses to the protective *** case study aims to numerically simulate selected destress blasts in the Czech part of the Upper Silesian Coal Basin and examine its impact on stress transfer to the safety pillar *** separate the area between the protective pillar and the longwall(LW),two fans of five 93-mm blast holes(length of 93e100 m)were drilled from the gate roads into the overburden *** set of blast holes was fired separately in two stages without time *** explosive charge(gelatin-type of explosive)of each stage is 3450 *** two DB stages were fired when the longwall face was approximately 158 m and 152 m away from the blast.A 3D mine-wide model is built and validated with in situ stress measured with *** and destressing in three 5-m thick coal seams are simulated in the *** modeling of DB is successfully conducted using a rock fragmentation factor a of 0.05 and a stress reduction/dissipation factor β of *** of transfer of additional stress from the mining area into the safety pillar is evaluated by comparison of yielding volume before and after *** is shown that yielding volume drops after DB by nearly 80%in the area of the destressing panel and near the safety shaft pillar.

关键词： Rockburst hazard Destress blasting(DB) Strata separation Safety pillar Numerical modeling Fragmentation factor Stress dissipation factor Longwall mining

Nano storage-boxes constructed by the vertical growth of MoS_(2 )on graphene for high-performance Li-S batteries

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Journal of Energy Chemistry 2022年第3期31卷 91-99,I0004页

作者： Bowen Cui Xiaomin Cai Wenqiang Wang petr Saha Gengchao Wang Shanghai Key Laboratory of Advanced Polymeric Materials Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China Centre of Polymer Systems University InstituteTomas Bata UniversityTř.T.Bati 5678Zlin 76001ZlínCzech Republic

In order to accelerate the reaction kinetics of lithium-sulfur batteries, the introduction of electro catalysis and proper structural control of the sulfur cathode is urgently needed. MoS_(2) nano sheets was selectively grown vertically (V-MoS_(2)) on the microwave-reduced graphene (rGO) sheets through chemical coupling to construct a self-supporting sulfur cathode with a nano storage-box structure (V-MoS_(2) as the wall and rGO as the bottom). RGO, which has a high conductivity of 37 S cm^(−1), greatly accelerates the transfer of electrons from the active sites on the edge of the layer to the solution. The introduction of carbon tubes can connect the abundant pores in the foam and act as a long-range conductive path. The 2D-orthogonal-2D structure maximally exposes the edge active sites of MoS_(2), and together with graphene form a nano reactor of sulfur, intermediate lithium polysulfides and discharge product Li_(2)S(2). The effective combination of the microstructure confinement of the nano storage-boxes and the efficient synchronous catalytic mechanism of V-MoS_(2) greatly improves the electrochemical performance of the lithium-sulfur batteries. As a result, the assembled lithium-sulfur battery displays a high initial discharge capacity of 1379 mAh g^(−1), good cycle stability (86% capacity retention after 500 cycles at 0.1C) and superior rate performance.

关键词： Edge-rich MoS_(2) Nano boxes Catalytic conversion Lithium-sulfur batteries

Highly surface electron-deficient Co_(9)S_(8) nanoarrays for enhanced oxygen evolution

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Green Energy & Environment 2020年第4期5卷 492-498页

作者： Haoxuan Zhang Jingyu Wang Qilin Cheng petr Saha Hao Jiang Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai200237China Centre of Polymer Systems University InstituteTomas Bata University in ZlinTrida T.Bati 5678Zlin76001Czech Republic

Tailoring valence electron delocalization of transition metal center is of importance to achieve highly-active electrocatalysts for oxygen evolution reaction(OER).Herein,we demonstrate a“poor sulfur”route to synthesize surface electron-deficient Co_(9)S_(8) nanoarrays,where the binding energy(BE)of Co metal center is considerably higher than all reported Co_(9)S_(8)-based *** resulting Co_(9)S_(8) electrocatalysts only require the overpotentials(h)of 265 and 326 mV at 10 and 100 mA cm^(-2) with a low Tafel slope of 56 mV dec^-(1) and a 60 hlasting stability in alkaline *** OER kinetics are greatly expedited with a low reaction activation energy of 27.9 kJ mol^-(1) as well as abundant OOH*key intermediates(24%),thus exhibiting excellent catalytic *** surface electron-deficient engineering gives an available strategy to improve the catalytic activity of other advanced non-noble electrocatalysts.

关键词： Electron deficiency Co_(9)S_(8) Nanoarray Electrocatalyst Oxygen evolution reaction

Investigation of the tribological performance of ionic liquids in non-conformal EHL contacts under electric field activation

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Friction 2020年第5期8卷 982-994页

作者： Michal MICHALEC petr SVOBODA Ivan KRUPKA Martin HARTL Aleksandar VENCL Faculty of Mechanical Engineering Brno University of TechnologyBrno 61669Czech Republic Central European Institute of Technology Brno University of TechnologyBrno 61200Czech Republic Faculty of Mechanical Engineering University of BelgradeBelgrade 11120Serbia South Ural State University Chelyabinsk 454080Russia

Real-time external alteration of the internal properties of lubricants is highly desirable in all mechanical systems. However, fabricating a suitable and effective smart lubricant is a long-lasting experimental process. In this study, the film thickness and frictional response of ionic liquid-lubricated non-conformal contacts to an electric field excitation under elastohydrodynamic conditions were examined. Film thickness was evaluated using a "ball-on-disc" optical tribometer with an electric circuit. Friction tests were carried on a mini traction machine (MTM) tribometer with a "ball-on-disc" rotation module and an electric circuit for contact area excitation. The results demonstrate that there is a difference in the behaviour of the ionic liquid during electric field excitation at the evaluated film thicknesses. The results of evaluated film thicknesses demonstrate that there is a difference in the behaviour of the ionic liquid during electric field excitation. Therefore, the ionic liquids could be a new basis for the smart lubrication of mechanical components. Moreover, the proposed experimental approach can be used to identify electrosensitive fluids.

关键词： friction thin film lubrication electro-rheological fluid smart fluid lubrication

Physics and applications of charged domain walls

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npj Computational Materials 2018年第1期4卷 119-129页

作者： petr S.Bednyakov Boris I.Sturman Tomas Sluka Alexander K.Tagantsev petr V.Yudin Institute of Physics Czech Academy of SciencesNa Slovance 218221 Prague 8Czech Republic Institute of Automation and Electrometry SB RAS Koptyug ave.1Novosibirsk 630090Russia CREAL3D SA Chemin du Paqueret 1 ACH-1025 Saint-SulpiceSwitzerland Swiss Federal Institute of Technology(EPFL) CH-1015 LausanneSwitzerland Ioffe Institute 194021 St.PetersburgRussia

The charged domain wall is an ultrathin(typically nanosized)interface between two domains;it carries bound charge owing to a change of normal component of spontaneous polarization on crossing the *** contrast to hetero-interfaces between different materials,charged domain walls(CDWs)can be created,displaced,erased,and recreated again in the bulk of a *** of the bound charge with free carriers is often necessary for stability of CDWs,which can result in giant two-dimensional conductivity along the *** in nominally insulating ferroelectrics,the concentration of free carriers at the walls can approach metallic ***,CDWs can be viewed as ultrathin reconfigurable strongly conductive sheets embedded into the bulk of an insulating *** feature is highly attractive for future *** last decade was marked by a surge of research interest in *** resulted in numerous breakthroughs in controllable and reproducible fabrication of CDWs in different materials,in investigation of CDW properties and charge compensation mechanisms,in discovery of light-induced effects,and,finally,in detection of giant two-dimensional *** present review is aiming at a concise presentation of the main physical ideas behind CDWs and a brief overview of the most important theoretical and experimental findings in the field.

关键词： walls breakthrough nominal

Do predator energy demands or previous exposure influence protection by aposematic coloration of prey？

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Current Zoology 2017年第3期63卷 259-267页

作者： petr VESELY Barbora ERNESTOVA OIdrich NEDVED Roman FUCHS Faculty of Science University of South Bohemia Branisovska 1760 37005 Ceske Budejovice Czech Republic

Growing evidence exists that aposematic and toxic prey may be included in a predator＇s diet when the predator experiences physiological stress. The tree sparrow Passer montanus is known to have a significant portion of aposematic and toxic ladybirds in its natural diet. Here, we present experi- ments testing the attack and eating rate of the tree sparrow toward the invasive aposematic harle- quin ladybird Harmonia axyridis. We wondered whether the sparrow＇s ability to prey on native ladybirds predisposes them to also prey on harlequin ladybirds. We compared the attack and eat- ing rates of tree sparrows of particular age and/or experience classes to test for any changes during ontogeny （hand-reared x young wild-caught xadult wild-caught） and with differing perceived lev- els of physiological stress （summer adult ~ winter adult）. Winter adult tree sparrows commonly at- tacked and ate the offered ladybirds with no evidence of disgust or metabolic difficulties after in- gestion. Naive and wild immature tree sparrows attacked the ladybirds but hesitated to eat them. Adult tree sparrows caught in the summer avoided attacking the ladybirds. These results suggest that tree sparrows are able to cope with chemicals ingested along with the ladybirds. This pre- adaptation enables them to include ladybirds in their diet; though they commonly do this only in times of shortage in insect availability （winter）. Young sparrows showed avoidance toward the chemical protection of the ladybirds.

关键词： chemical protection toxic prey predation visual signal warning signal.

New Physicochemical Treatment Method of Poppy Seeds for Agriculture and Food Industries

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Plasma Science and Technology 2013年第9期15卷 935-938页

作者： Bozena ER Iveta GAJDOV Michal ER'Y petr PATENKA Institute of Nanobiology and Structural Biology GCRC Academy of Sciences of the Czech RepublicDepartment of NanobiotechnologyNa Sadkach 7Ceske Budejovicecz-37005Czech Republic Department of Biology Faculty of EducationUniversity of South Bohemia in Ceske BudejoviceJeronymova 10Ceske Budejovicecz-37115Czech Republic Department of Applied Physics and Technics Faculty of EducationUniversity of South Bohemia in Ceske BudejoviceJeronymova 10Ceske Budejovicecz-37115Czech Republic

Poppy seeds （Papaver somniferum L.） are often attacked by various fungal dis- eases, and their field germination rate is low. The aim of this experiment was to increase the germination rate and growth of seedlings by modifying the poppy seeds using cold plasma dis- charge. The seeds were treated in a Plasonic AR-550-M under power of 500 W with argon gas flow of 50 mL/min, oxygen gas flow of 50 mL/min for different time durations in seconds （0, 180, 300, 600, 1800, 3000, 4200, and 5400）. The seed germination rate and growth of the seedlings were recorded. Cold plasma positively affected the seed germination rate for time exposure between 180～3000 s. Seedling acceleration on the sixth day of the experiment showed the highest values at exposure 180～600 s. Cold plasma seems to be a good physicochemical way to modify seeds without chemical agronomical application.

关键词： biotechnology early growth low-pressure discharge Papaver somniferum,seed modification seed germination

Greenhouse gas emissions from thermal treatment o non-recyclable municipal waste

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Frontiers of Chemical Science and Engineering 2018年第4期12卷 815-831页

作者： Tomas Ferdan Martin Pavlas Vlastimlr Nevrly Radovan Sompllak petr Stehllk Institute of Process Engineering Faculty of Mechanical EngineeringBmo University of Technology61669 BmoCzech Republic Sustainable Process Integration Laboratory-SPIL NETME CentreFaculty of Mechanical Engineering Bmo University of Technology61669 BmoCzech Republic

This paper analyses factors affecting the production of greenhouse gases from the treatment of residual municipal waste. The analysis is conducted so that the environmentally-friendly decision-making criteria may be later implemented into an optimisation task, which allocates waste treatment capacities. A simplified method of life cycle assessment is applied to describe environmental impact of the allocation. Global warming potential (GWP) is employed as a unit to quantify greenhouse gases (GHG) emissions. The objective is to identify the environmental burdens and credits measured by GWP for the three fundamental methods for treatment of residual waste unsuitable for material recovery. The three methods are waste-to-energy (WTE), landfilling and mechanical-biological treatment (MBT) with subsequent utilization of refuse-derived fuel. The composition of the waste itself and content of fossil-derived carbon and biogenic carbon are important parameters to identify amounts of GHG. In case of WTE, subsequent use of the energy, e.g., in district heating systems in case of heat, is another important parameter to be considered. GWP function dependant on WTE capacity is introduced. The conclusion of this paper provides an assessment of the potential benefits of the results in optimisation tasks for the planning of overall strategy in waste management.

关键词： waste management greenhouse gases global warming potential allocation planning waste-to-energy

Numerical Simulation of Airfoil Vibrations Induced by Turbulent Flow

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Communications in Computational Physics 2015年第1期17卷 146-188页

作者： Miloslav Feistauer Jaromır Horacek petr Svacek Charles University in Prague Faculty of Mathematics and PhysicsSokolovska 8318675 Praha 8Czech Republic Institute of Thermomechanics Academy of Sciences of the Czech RepublicDolejskova 518200 Praha 8Czech Republic Czech Technical University Prague Faculty of Mechanical EngineeringKarlovo nam.1312135 Praha 2Czech Republic

The subject of the paper is the numerical simulation of the interaction of two-dimensional incompressible viscous flow and a vibrating airfoil with large *** airfoil with three degrees of freedom performs rotation around an elastic axis,oscillations in the vertical direction and rotation of a *** numerical simulation consists of the finite element solution of the Reynolds averaged Navier-Stokes equations combined with Spalart-Allmaras or k−ω turbulence models,coupled with a system of nonlinear ordinary differential equations describing the airfoil motion with consideration of large *** time-dependent computational domain and approximation on a moving grid are treated by the Arbitrary Lagrangian-Eulerian formulation of the flow *** to large values of the involved Reynolds numbers an application of a suitable stabilization of the finite element discretization is *** developed method is used for the computation of flow-induced oscillations of the airfoil near the flutter instability,when the displacements of the airfoil are large,up to±40 degrees in *** paper contains the comparison of the numerical results obtained by both turbulence models.

关键词： Fluid-structure interaction flow induced vibrations Reynolds averaged NavierStokes equations turbulence models finite element method coupling algorithm