检索结果-南通市图书馆

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

在线全文

学校读者我要写书评

暂无评论

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？

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

在线全文

学校读者我要写书评

暂无评论

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Characterization of Curing and Bonding of Wood with Adhesive Mixtures of Liquefied Wood and Hexamethylenediamine

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 Renewable Materials 2023年第2期11卷 991-1001页

作者： JureŽigon VitŠeda petrČermák MilanŠernek Department of Wood Science and Technology Biotechnical FacultyUniversity of LjubljanaLjubljana1000Slovenia Department of Wood Science and Technology Faculty of Forestry and Wood TechnologyMendel University in BrnoBrno61300Czech Republic

Various crosslinking agents can be added to the formulations of natural-based adhesives for wood bonding in order to achieve better durability and higher strength of the formed *** the present study,the effect of hexamethylenediamine(HMDA)addition on the performance of liquefied wood(LW)adhesive for wood bonding is *** scanning calorimetry showed the improved thermal stability and crosslinking of the LW adhesive with *** intensified presence of amide linkages(C–N bonds)was found in LW+HMDA with attenuated total reflection Fourier transform infrared *** of the bonded joints using an automated bonding evaluation system showed that a higher press temperature resulted in stronger bonds for both types of ***,the addition of HMDA to LW adhesive improved the bond strength of the joints and accelerated the crosslinking of the ***,with a tensile shear strength of(6.76±2.16)N×mm^(−2)(for LW)and(6.89±2.10)N×mm^(−2)(for LW+HMDA),both adhesives were found to be unsuitable for interior non-structural *** addition,the acidity of LW resulted in relatively high wood failure(70%)in the adhesive joints *** crosslinking of LW with HMDA was reflected in improved resistance of LW+HMDA adhesive joints to water *** conclusion,HMDA is a promising additive for improving the adhesive performance of LW adhesives.

关键词： Adhesive bonding hexamethylenediamine liquefied wood

On the possibility of identifying human subjects using behavioural complexity analyses

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Electrical and Electronic Engineering in China 2016年第4期4卷 261-269页

作者： petr Kloucek Armin von Gunten CAMPsyN SUPAA HSpital de Cery Route de Cery Lausanne University Hospital CH-1008 Prilly Lausanne Switzerland SUPAA Hopital de Cery Route de Cery Lausanne University Hospital CH-1008 Prilly Lausanne Switzerland

Identification of human subjects using a geometric approach to complexity analysis of behavioural data is designed to provide a basis for a more precise diagnosis leading towards personalised medicine. Methods： The approach is based on capturing behavioural time-series that can be characterized by a fractional dimension using non-invasive longer-time acquisitions of heart rate, perfusion, blood oxygenation, skin temperature, relative movement and steps frequency. The geometry based approach consists in the analysis of the area and centroid of convex hulls encapsulating the behavioural data represented in Euclidian index spaces based on the scaring properties of the self-similar normally distributed behavioural time-series of the above mentioned quantities. Results： An example demonstrating the presented approach of behavioural fingerprinting is provided using sensory data of eight healthy human subjects based on approximately fifteen hours of data acquisition. Our results show that healthy subjects can be factorized to different similarity groups based on a particular choice of a convex hull in the corresponding Euclidian space. One of the results indicates that healthy subjects share only a small part of the convex hull pertaining to a highly trained individual from the geometric comparison point of view. Similarly, the presented pair-wise individual geometric similarity measure indicates large differences among the subjects suggesting the possibility of neuro-fingerprinting. Conclusions： Recently introduced multi-channel body-attached sensors provide a possibility to acquire behavioural time-series that can be mathematically analysed to obtain various objective measures of behavioural patterns yielding behavioural diagnoses favouring personalised treatments of, e.g., neuropathologies or aging.

关键词： behavioural complexity indexing behavioural fingerprinting behavioural hysteresis non-disruptivepersonalized medicine

Soil erosion: An important indicator for the assessment of land degradation neutrality in Russia

在线全文

学校读者我要写书评

暂无评论

International Soil and Water Conservation Research 2020年第4期8卷 418-429页

作者： petr Tsvmbarovich German Kust Mikhail Kumani Valentin Golosov Olga Andreeva Institute of Geography RAS Russian Academy of SciencesMoscowRussia Lomonosov Moscow State University MoscowRussia Kursk State University KurskRussia

This review of soil erosion(SE)studies in Russia focuses on two main tasks:(i)ensuring the completeness and reliability of SE data in Russia,a large country(17.1 million km2)with a variety of natural and socio-economic causes of land degradation,(ii)assessing the possibility of including a SE indicator among the indicators of land degradation neutrality(LDN).A wide range of statistical,remote sensing,mathematical modeling *** results of scientific and field studies obtained at different levels were *** is asserted that in Russia the total area of eroded lands and those under erosion risk occupy more than 50%of all agricultural lands,whereas soil fertility of croplands decreased in Soviet time(from 1950s to 1980s)by 30-60%only due to water ***,recent scientific studies indicate a decrease in erosion rate and in the area of eroded land during the last 30-40 years as a result of abandonment of arable land and subsequent overgrown with natural *** climate change resulting in decrease of the depth of soil freezing,flow of spring runoff also adds to the decrease of soil *** SE indicator was suggested as an important complement to three global LDN *** national and subnational level,it can be interpreted through such indices as"Rate of soil loss"(ton ha-1 yr-1)and"Total soil loss"(1000 tons,in certain area during selected time period).At local level the set of indices can be wider and site-specific,including those obtained through remote sensing data by using the classifier of thematic applications of remote sensing technologies;the example was tested at the local site.

关键词： Russian Federation Soil erosion Land degradation neutrality

ZnO@MOF@PANI core-shell nanoarrays on carbon cloth for high-performance supercapacitor electrodes

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 Energy Chemistry 2019年第8期28卷 124-131,I0005页

作者： Chunmei Zhu Ying He Yijun Liu Natalia Kazantseva petr Saha Qilin Cheng Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and Engineering East China University of Science and TechnologyShanghai 200237 China Centre of Polymer Systems Tomas Bata University in Zlinnam. T. G. Masaryka 5555 760 01 Zlin Czechia

Hierarchical ZnO@metal-organic framework @polyaniline(ZnO@MOF@PANI) core-shell nanorod arrays on carbon cloth has been fabricated by combining electrodeposition and hydrothermal method. Well-ordered Zn O nanorods not only act as a scaffold for growth of MOF/PANI shell but also as Zn source for the formation of MOF. The morphology of ZnO@MOF@PANI composite is greatly influenced by the number of PANI electrodeposition cycles. Their structural and electrochemical properties were characterized with different techniques. The results indicate that the Zn O@MOF@PANI with 13 CV cycles of PANI deposition demonstrates the maximum specific capacitance of 340.7 F g-1 at 1.0 A g-1, good rate capability with84.3% capacitance retention from 1.0 to 10 A g-1 and excellent cycling life of 82.5% capacitance retention after 5000 cycles at high current density of 2.0 A g-1. This optimized core-shell nanoarchitecture endows the composite electrode with short ion diffusion pathway, rapid ion/electron transfer and high utilization of active materials, which thus result in excellent electrochemical performance of the ternary composite.

关键词： Metal-oragnic framework Polyaniline Core-shell nanoarrays Supercapacitor Electrochemical properties