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21.
This paper describes computational simulations of the propagation of a magnetised plasma to inner parts of porous solids or cavities. The geometry of such a problem requires generally three-dimensional simulations due to lack of symmetry. We propose a hybrid method to overcome limitations of commonly used particle and fluid models. The hybrid method combines particle and fluid parts in an iterative manner to obtain results in a short time preserving information about individual particles.The hybrid model is applied to a study of ion propagation to a cylindrical hole in a conductive solid. The influence of a magnetic field and its orientation is discussed. The presence of the magnetic field enhances the flux of ions to the hole; the influence of voltage bias on the substrate is highly important. 相似文献
22.
Vojtech VargaMichal Horá?ek Zdeněk BastlJan Merna Ivana Císa?ováJan Sýkora Ji?í Pinkas 《Catalysis Today》2012,179(1):130-139
The efficient catalytic dehydropolymerization of phenylsilane by homogeneous zirconocene bissilanolates ([{(c-C5H9)7Si8O12O}2Zr(η5-C5H5)2] (1a); [{(c-C5H9)7Si8O12O}2Zr(η5-C5H4Bu)2] (1b) [{(c-C5H9)7Si7O9(OSiMe3)O2}Zr(η5-C5H5)2] (4); [{(Me3CO)3SiO}2Zr(η5-C5H5)2] (5)) and chlorosilanolates ([{(c-C5H9)7Si8O12O}ZrCl(η5-C5H4Bu)2] (2); ([{(c-C5H9)7Si7O9O3}Zr2Cl(η5-C5H5)4] (3a); [{(c-C5H9)7Si7O9O3}Zr2Cl(η5-C5H4Bu)4] (3b)) has been demonstrated. The presence of at least one silanol ligand in the zirconocene moiety was found essential for high catalytic performance. Solid state structure of complex 1a was determined by single crystal X-ray diffraction analysis. A series of nine zirconocene-siliceous catalysts were prepared by grafting of zirconocene moiety onto silica using three general methods: (a) reaction of [(η5-C5H5)2ZrCl2] with silica in the presence of NEt3; (b) reaction of [(η5-C5H5)2ZrMe2] with silica; (c) reaction of solely [(η5-C5H5)2ZrCl2] with silica. Supported catalysts were characterized by ICP-MS, FT-IR, TGA and selected examples by XPS analysis. Those catalysts prepared by method (a) and (b) were found efficient in the phenylsilane polymerization although a higher Zr/monomer ratio had to be used in comparison with homogeneous analogues. The low concentration of residual silanol groups in supported catalysts was found essential for their high catalytic performance. Advantageous reusability of supported catalysts was demonstrated using SiO2(500)/Cp2ZrCl2/NEt3(5.8). The catalytic performance was retained in three consecutive cycles producing polymers with almost identical properties. 相似文献
23.
Dagmar Chudobova Lukas Nejdl Jaromir Gumulec Olga Krystofova Miguel Angel Merlos Rodrigo Jindrich Kynicky Branislav Ruttkay-Nedecky Pavel Kopel Petr Babula Vojtech Adam Rene Kizek 《International journal of molecular sciences》2013,14(7):13592-13614
Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes. 相似文献
24.
Martina Ussia Mario Urso Kristyna Dolezelikova Hana Michalkova Vojtech Adam Martin Pumera 《Advanced functional materials》2021,31(27):2101178
Bacterial biofilms are multicellular communities firmly attached to solid extracellular substrates. They are considered the primary cause of huge economic losses, from medicine due to medical implants’ failure to large infrastructure due to enhanced pipe corrosion. Therefore, their eradication is highly desirable. Here, the preparation of ZnO self-propelled micromotors is reported, programming their morphology and motion properties through Ag doping. The ZnO:Ag micromotors actively move upon light irradiation via a self-electrophoretic mechanism, showing excellent light-controlled on/off switching motion. At the same time, the rapid and effective removal of both gram-positive and gram-negative bacteria biofilms from the solid surface is demonstrated, exploiting the well-known antibacterial activity of both Ag and ZnO as well as the enhanced diffusion of the micromotors. The new concept for the low-cost and scalable preparation of chemically programmable Ag-doped ZnO micromotors here illustrated opens a new route toward the formulation of a new class of light-driven semiconducting self-propelled micromotors for environmental applications. 相似文献
25.
Sylva Prerostova Petre I. Dobrev Vojtech Knirsch Jana Jarosova Alena Gaudinova Barbara Zupkova Ilja T. Pril Tibor Janda Betislav Brzobohatý Jan Skalk Radomira Vankova 《International journal of molecular sciences》2021,22(5)
Plant survival in temperate zones requires efficient cold acclimation, which is strongly affected by light and temperature signal crosstalk, which converge in modulation of hormonal responses. Cold under low light conditions affected Arabidopsis responses predominantly in apices, possibly because energy supplies were too limited for requirements of these meristematic tissues, despite a relatively high steady-state quantum yield. Comparing cold responses at optimal light intensity and low light, we found activation of similar defence mechanisms—apart from CBF1–3 and CRF3–4 pathways, also transient stimulation of cytokinin type-A response regulators, accompanied by fast transient increase of trans-zeatin in roots. Upregulated expression of components of strigolactone (and karrikin) signalling pathway indicated involvement of these phytohormones in cold responses. Impaired response of phyA, phyB, cry1 and cry2 mutants reflected participation of these photoreceptors in acquiring freezing tolerance (especially cryptochrome CRY1 at optimal light intensity and phytochrome PHYA at low light). Efficient cold acclimation at optimal light was associated with upregulation of trans-zeatin in leaves and roots, while at low light, cytokinin (except cis-zeatin) content remained diminished. Cold stresses induced elevation of jasmonic acid and salicylic acid (in roots). Low light at optimal conditions resulted in strong suppression of cytokinins, jasmonic and salicylic acid. 相似文献
26.
A new robust proportional‐integral‐derivative (PID)–proportional‐sum‐derivative (PSD) controller design method based on linear (bilinear) matrix inequalities (LMI, BMI) is proposed for uncertain affine linear system. The design procedure guarantees the parameter dependent quadratic stability, and guaranteed cost control with a new quadratic cost function (LQRS) including the derivative term for the state vector as a tool to influence the overshoot and response rate. The second approach to the PSD controller design procedure is based on a Lyapunov function with a special term corresponding to the time‐delay part of the control algorithm. The results obtained are illustrated on three examples to show the robust PID, PSD control design procedure and the influence of the choice of matrix S in the extended cost function. 相似文献
27.
Vojtech Svoboda Heinz Wenzl Rudi Kaiser Andreas Jossen Ian Baring-Gould James Manwell Per Lundsager Henrik Bindner Tom Cronin Per Nrgrd Alan Ruddell Adolfo Perujo Kevin Douglas Carlos Rodrigues Antnio Joyce Stathis Tselepis Nico van der Borg Frans Nieuwenhout Nigel Wilmot Florence Mattera Dirk Uwe Sauer 《Solar Energy》2007,81(11):1409-1425
Operating conditions in off-grid renewable energy systems (RES) vary significantly in different applications and locations. To describe RES and the operating conditions of their components it is useful to define categories of similar operating conditions. Categories can also be used for lifetime considerations of RES components, for making recommendations and for analysing the properties and performance of a RES and its components. Categories support system designers and an economic analysis. This paper describes the process and the results of creating RES categories of similar operating conditions for batteries. Categories are defined in such a way that batteries belonging to the same category are subjected to similar operating conditions and a similar combination of stress factors. The results provide a comprehensive overview of battery operating conditions in existing off-grid renewable energy systems. This work is part of the EU research project Benchmarking.1 相似文献
28.
Michal Pechoucek Ales Riha Jiri Vokrinek Vladimir Marik Vojtech Prazma 《国际生产研究杂志》2013,51(15):3681-3692
This paper presents work carried out within the 'ExPlanTech' project (IST-1999-20171) funded in part by the European Commission's Information Technologies Programme. The mission of the ExPlanTech technology transfer project is to introduce, customize and exploit the multi-agent production planning technology (ProPlanT multi-agent system research prototype) in two specific industrial enterprises. An agent-driven service negotiations and decision process, based on usagecentred knowledge about task requirements, substitutes the traditional production planning activity. We introduce a methodology for integration of the projectdriven production planning based on agent-based engineering within the existing enterprise resource planning system. This novel production planning technology will facilitate optimization of resource utilization and supplier chain while meeting the customer demands. This paper describes a FIPA-compliant implementation of the ExPlanTech technology at the LIAZ Pattern Shop manufacturing company. We describe the structure of the agent community, types of agents, implementation of the planning strategy and its incorporation within the real production environment. 相似文献
29.
Jaromir Gumulec Michaela Fojtu Martina Raudenska Marketa Sztalmachova Anna Skotakova Jana Vlachova Sylvie Skalickova Lukas Nejdl Pavel Kopel Lucia Knopfova Vojtech Adam Rene Kizek Marie Stiborova Petr Babula Michal Masarik 《International journal of molecular sciences》2014,15(12):22960-22977
Doxorubicin is an effective chemotherapeutic drug, however, its toxicity is a significant limitation in therapy. Encapsulation of doxorubicin inside liposomes or ferritin cages decreases cardiotoxicity while maintaining anticancer potency. We synthesized novel apoferritin- and liposome-encapsulated forms of doxorubicin (“Apodox” and “lip-8-dox”) and compared its toxicity with doxorubicin and Myocet on prostate cell lines. Three different prostatic cell lines PNT1A, 22Rv1, and LNCaP were chosen. The toxicity of the modified doxorubicin forms was compared to conventional doxorubicin using the MTT assay, real-time cell impedance-based cell growth method (RTCA), and flow cytometry. The efficiency of doxorubicin entrapment was 56% in apoferritin cages and 42% in the liposome carrier. The accuracy of the RTCA system was verified by flow-cytometric analysis of cell viability. The doxorubicin half maximal inhibition concentrations (IC50) were determined as 170.5, 234.0, and 169.0 nM for PNT1A, 22Rv1, and LNCaP, respectively by RTCA. Lip8-dox is less toxic on the non-tumor cell line PNT1A compared to doxorubicin, while still maintaining the toxicity to tumorous cell lines similar to doxorubicin or epirubicin (IC50 = 2076.7 nM for PNT1A vs. 935.3 and 729.0 nM for 22Rv1 and LNCaP). Apodox IC50 was determined as follows: 603.1, 1344.2, and 931.2 nM for PNT1A, 22Rv1, and LNCaP. 相似文献
30.
The paper addresses the problem of designing a robust output/state model predictive control for linear polytopic systems with input constraints. The new predictive and control horizon model is derived as a linear polytopic system. Lyapunov function approach guarantees the quadratic stability and guaranteed cost for closed-loop system. The invariant set and an algorithm approach similar to Soft Variable-Structure Control (SVSC), ensures input constraints for the model predictive plant control system. In the proposed control scheme, the required on-line computation load is significantly less than in MPC literature, which opens the possibility to use these control design schemes not only for plants with slow dynamics, but also for faster ones. 相似文献