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Advantageous mechanochemical synthesis of copper(Ⅰ)selenide semiconductor,characterization,and properties

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Frontiers of Chemical Science and Engineering 2022年第3期16卷 433-442页

作者： Katarína Gáborová marcela Achimovičová michal Hegedüs vladim.r Girman mária Kaňuchová Erika Dutková Institute of Geotechnics Slovak Academy of SciencesKošice04001Slovakia Institute of metallurgy Faculty of MaterialsMetallurgy and RecyclingTechnical UniversityKošice04201Slovakia Synthon s.r.o.Blansko67801Czech Republic Faculty of Science Pavol JozefŠafárik UniversityKošice04154Slovakia Institute of Earth resources Faculty of MiningEcologyProcess Control and GeotechnologiesTechnical UniversityKošice04200Slovakia

Copper(I)selenide-nanocrystalline semiconductor was synthesized via one-step mechanochemical synthesis after 5 min milling in a planetary ball *** kinetics of synthesis was followed by X-ray powder diffraction analysis and specific surface area measurements of milled 2Cu/Se *** X-ray diffraction confirmed the orthorhombic crystal structure of Cu_(2)Se with the crystallite size∼25 *** surface chemical structure was studied by X-ray photoelectron spectroscopy,whereby the binding energy of the Cu 2p and Se 3d signals corresponded to Cu^(+)and Se^(2−)oxidation *** electron microscopy revealed agglomerated nanocrystals and confirmed their orthorhombic structure,as *** optical properties were studied utilizing ultraviolet-visible spectroscopy and photoluminescence *** direct bandgap energy 3.7 eV indicated a blue-shift phenomenon due to the quantum size *** type of Cu_(2)Se synthesis can be easily adapted to production dimensions using an industrial vibratory *** advantages of mechanochemical synthesis represent the potential for inexpensive,environmentally-friendly,and waste-free manufacturing of Cu_(2)Se.

关键词： Cu_(2)Se berzelianite nanocrystalline semiconductor mechanochemical synthesis planetary ball mill

Applicability of high-temperature cooling systems in different European countries from the view of the condensation risk

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Building Simulation 2021年第5期14卷 1453-1466页

作者： vladim.r Zmrhal martin Bartak Czech Technical University in Prague Faculty of Mechanical EngineeringDepartment of Environmental Engineering Technicka 416000 Prague 6Czech Republic

Due to the different approaches in determining the ventilation airflow rate per person for workspaces,where high-temperature air conditioning systems are used for air conditioning,problems with the condensation of water vapour on the cold surfaces of the system can *** article analyses the risk of condensation in various European cities using the available climatic *** with cooling ceilings and cooling beams with a ventilation device operating in parallel are taken into *** ventilation airflow rates per person were *** the example of a room equipped with high-temperature cooling,an energy simulation calculation is performed,which includes a ventilation and air-conditioning system with the possibility of capacity *** is clear from the results that the condensation of water vapour can be prevented by technical measures at the cost of reducing the cooling capacity,which can affect the achievement of the thermal comfort of those *** the end,suitable solutions are discussed,which should already be adopted at the time the device is designed so that the risk of condensation is not a major obstacle in the operation of these energy-efficient *** irreplaceable role in the operation of high-temperature cooling systems is played by a measurement and control system with a suitable algorithm to prevent condensation.

关键词： ventilation air-conditioning cooled ceilings chilled beams low energy cooling risk of condensation

Determination of the sensible heat effectiveness and pressure loss of a rotary regenerative heat exchanger using CFD

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Building Simulation 2023年第6期16卷 869-887页

作者： vladim.r Zmrhal Petr Zelenský Jindřich Boháč martin Barták miroslav Kučera roman Vavřička Faculty of mechanical Engineering Department of Environmental EngineeringCzech Technical University in PragueTechnická416000Prague 6Czech Republic

The paper presents a new method to determine the sensible effectiveness and pressure loss of rotary regenerative heat exchangers using computational fluid dynamics(CFD).It is based on CFD simulations of a single thermal wheel microchannel with a small cross-sectional area and thin walls,with cyclic inlet and outlet boundary *** unique measurement set-ups were designed and built for the experimental measurement of the heat exchanger *** different types of thermal wheels were manufactured,measured,and simulated in ANSYS *** wheels achieve an effectiveness greater than 73%under certain(air flow)conditions,which is the minimum effectiveness required by Ecodesign(in the EU).For the examined exchangers,the effectiveness ranges from 66.5%to 83.3%,depending on the boundary conditions and geometric parameters of the *** highest sensible effectiveness is achieved by heat exchangers with the largest heat exchange surface Ac;on the other hand,these wheels have the largest pressure *** paper discusses the use of a simplifiedε-NTU correlation model for the HVAC systems(typically C*=1).The correlation model and CFD results were compared and found to be different from each *** results of the CFD simulation were compared with measurements to prove that the proposed simulation method can predict the behaviour of the real heat exchanger as a *** was demonstrated that the sensible effectiveness and pressure loss of the rotary heat exchanger predicted by the CFD simulations correspond well to the measured values within the measurement uncertainty±1.3%.The proposed method can be used for the comparison of different rotary regenerative heat exchangers before their manufacturing and for verification that they meet the EU Ecodesign requirements set by the current *** reduces the cost of the initial optimisation and testing of new designs.

关键词： rotary heat exchanger heat wheel microchannel heat recovery sensible effectiveness pressureloss computer fluid dynamics experiment

Is Chloroplast movement in Tobacco Plants Influenced Systemically after Local Illumination or Burning Stress?

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Journal of Integrative Plant Biology 2008年第10期50卷 1292-1299页

作者： Jan Nau monika rolencov vladim.ra Hlavkov Laboratory of Biophysics Department of Experimental Physics Palacky' University tr. Svobody 26 77146 Olomouc Czech Republic

Chloroplast movement has been studied in many plants mainly in relation to the local light, mechanical or stress effects. Here we investigated possible systemic responses of chloroplast movement to local light or burning stress in tobacco plants （Nicotisna tabacum cv. Samsun）. Chloroplast movement was measured using two independent methods： one with a SPAD 502 Chlorophyll meter and another by collimated transmittance at a selected wavelength （676 nm）. A sensitive periodic movement of chloroplasts was used in high or low （2 000 or 50 μmol/m2 per s photosynthetically active radiation, respectively） cold white light with periods of 50 or 130 min. measurements were carried out in the irradiated area, in the non-irradisted area of the same leaf or in the leaf located on the stem below the irradiated or bumed one. No significant changes in systemic chloroplast movement in non-irradiated parts of the leaf and in the non-treated leaf were detected. Our data indicate that chloroplast movement in tobacco is dependent dominantly on the intensity and spectral composition of the incident light and on the local stimulation and state of the target tissue. No systemic signal was strong enough to evoke a detectable systemic response in chloroplast movement in distant untreated tissues of tobacco plants.

关键词： buming chloroplast movement irradiance systemic response tobacco.

Computational simulation methods for fiber reinforced composites

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Frontiers of Structural and Civil Engineering 2010年第3期4卷 396-401页

作者： vladim.r KOmPIŠ Zuzana mUrČINKOVÁ Sergey rJASANOW richards GrZIBOVSKIS QinghuaQIN DSSI j.s.c.Wolkrova 482105 BratislavaSlovakia Technical University Košice Faculty of Manufacturing TechnologiesŠtúrova 3108001 PrešovSlovakia Department of mathematics and Computer Science University of SaarlandSaarbrückenGermany Department of Engineering Australian National UniversityACTAustralia

Trefftz-finite element method(Trefftz-FEm),adaptive cross approximation BEm(ACA BEm)and continuous source function method(CSFm)are used for the simulation of composites reinforced by short fibers(CrSF)with the aim of showing the possibilities of reducing the problem of complicated and important interactions in such composite materials.

关键词： Trefftz-finite element method(Trefftz-FEm) adaptive cross approximation BEm(ACA BEm) method of continuous source functions composite materials short fibers

Possibilities of GPS Kinematic measurements for Geological Survey in East Slovakia

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Geo-Spatial Information Science 2002年第4期5卷 21-25页

作者： vladim.r Sedlák Viera Huríková Sona molíková Department of Geodesy and Geophysics The Technical University of Kosice Park Komenskeho 19 SK-043 84 Kosice Slovakia

This paper deals with transformation procedures for observed GPS data from the world geodetic system WGS84 into the national geodetic grid datum SUTCN （system of united trigonometric cadaster network） and Baa（the Baltic Sea after adjustment）.Transformation from WGS84 into SUTCN is performed most frequently by means of the 7element Helmert transformation with three identical *** network was adjusted by two ways.

关键词： kinematic GPS technology 3D coordinate transformations free adjustment adjustment with constraints

Assessment of sensory impairment in older adults with dementia

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Journal of Otology 2024年第4期19卷 220-226页

作者： Nikol Gottfriedová martina Kovalová Eva mrázková Ondrej machaczka Veronika Koutná vladim.r Janout Jana Janoutová Department of Epidemiology and Public Health Faculty of MedicineUniversity of OstravaCzech Republic Department of Healthcare management and Public Health Faculty of Health SciencesPalackýUniversity OlomoucCzech Republic Center for research and Science Faculty of Health SciencesPalackýUniversity OlomoucCzech Republic Department of Public Health Faculty of Medicine and DentistryPalackýUniversity OlomoucCzech Republic

Background:Over 55 million people worldwide are living with *** rate of cognitive decline increases with age,and loss of senses may be a contributing ***:This study aimed to analyze hearing,olfactory function,and color vision in patients with *** and methods:The sample comprised 40 patients with dementia and 37 cognitively normal controls aged 41–85 *** participants underwent conventional pure-tone audiometry and a screening version of the Hearing Handicap Inventory for Adults,the Odorized markers Test of olfactory function and the Ishihara color vision *** effects of comorbidities and lifestyle factors were also ***:Patients with dementia had significantly worse hearing at almost all frequencies tested and significantly greater olfactory impairment than cognitively normal *** vision impairment was found in less than 8%of the sample,with no significant difference between the *** of two senses(hearing and olfaction)was significantly more common in patients with dementia than in ***:Individuals with dementia were found to have sensory decline,namely hearing and olfactory *** vision was rarely impaired in the *** with dementia tended to have more multisensory impairments than controls.

关键词： Dementia Cognitive impairment Sensory impairment Hearing loss Olfactory loss Color vision

Entropy—A Universal Concept in Sciences

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Natural Science 2014年第7期6卷 552-564页

作者： vladim.r majerník mathematical Institute Slovak Academy of Sciences Bratislava Slovakia

Entropy represents a universal concept in science suitable for quantifying the uncertainty of a series of random events. We define and describe this notion in an appropriate manner for physicists. We start with a brief recapitulation of the basic concept of the theory probability being useful for the determination of the concept of entropy. The history of how this concept came into its to-day exact form is sketched. We show that the Shannon entropy represents the most adequate measure of the probabilistic uncertainty of a random object. Though the notion of entropy has been introduced in classical thermodynamics as a thermodynamic state variable it relies on concepts studied in the theory of probability and mathematical statistics. We point out that whole formalisms of statistical mechanics can be rewritten in terms of Shannon entropy. The notion “entropy” is differently understood in various science disciplines: in classical physics it represents the thermodynamical state variable;in communication theory it represents the efficiency of transmission of communication;in the theory of general systems the magnitude of the configurational order;in ecology the measure for bio-diversity;in statistics the degree of disorder, etc. All these notions can be mapped on the general mathematical concept of entropy. By means of entropy, the configurational order of complex systems can be exactly quantified. Besides the Shannon entropy, there exists a class of Shannon-like entropies which converge, under certain circumstances, toward Shannon entropy. The Shannon-like entropy is sometimes easier to handle mathematically then Shannon entropy. One of the important Shannon-like entropy is well-known Tsallis entropy. The application of the Shannon and Shannon-like entropies in science is really versatile. Besides the mentioned statistical physics, they play a fundamental role in the quantum information, communication theory, in the description of disorder, etc.

关键词： Probability Uncertainty Shannon Entropy Shannon-Like Entropies

Electric Spark Sensitivity of Polynitro Compounds. Part V. A relationship between Electric Spark and Impact Sensitivities of Energetic materials

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含能材料 2001年第2期9卷 60-65页

作者： vladim.rZEmAN SvatoplukZEmAN 等 DepartmentofTheoryandTechnologyofExplosives UniversityofPardubiceCZ－53210PardubictheCzechRepublic De

The spark energy, E ES , required for 50 percent initiation probability of 41 polynitro compounds was determined. The relationships between the E ES values and impact sensitivity, expressed as drop energies E d of the "first reaction", were established and discussed. The conclusion is made that depending on intermolecular interaction factors in crystals of energetic materials, the mechanism of impact energy transition to the reaction centre of their molecule can be differ from that of transition of energy of electric spark.

关键词：电火花灵敏性含能材料冲击敏感性