Characterization of 1-D Nanostructures by SPM Methods

Dizertační práce je zaměřena na charakterizaci uhlíkových nanotrubic a stříbrných nanodrátu rastrovací sondovou mikroskopií -- rastrující tunelovou mikroskopií (STM), mikroskopií atomárních sil (AFM), vodivostní mikroskopií AFM (CAFM) a mikroskopií blízkého pole (SNOM). Uhlíkové nanotrubice byly analyzovány mikroskopiemi STM, AFM a CAFM. V navržené aparatuře byly připraveny stříbrné nanodráty depozicí do polykarbonátových membrán, analyzovány z hlediska geometrie (AFM), lokální vodivosti (CAFM) a optických vlastností (SNOM, mikroreflexní spektroskopie). Bylo zjištěno, že preferenční typ uhlíkových nanotrubic závisí na zpusobu jejich výroby. Vodivostní měření prokázala obdobnou citlivost na rozložení multivrstev nanotrubic jako u STM. Stříbrné nanodráty odpovídají svojí geometrií depozičním podmínkám (AFM), vykazují polovodičové chování (CAFM) a po osvětlení bílým světlem vyzakazují lokalizované plasmonové rezonance.The thesis is aimed at the characterization of carbon nanotubes and silver nanowires by Scanning Probe Microscopy, namely Scanning Tunneling Microscopy (STM), Atomic Force Microscopy (AFM), Conductive AFM (CAFM) and Scanning Near-Field Optical Microscopy (SNOM). Carbon nanotubes were analyzed by STM, AFM and CAFM microscopy. In a designed apparatus the silver nanowires were fabricated by template assisted deposition and were analyzed with respect to their geometry (AFM), local conductivity (CAFM) and optical properties (SNOM, microreflex spectroscopy). It was found that preferential type of carbon nanowires depends on the fabrication process. The measurements of local conductivity of the nanotubes revealed the similarity with the STM measurements. The AFM measurements of silver nanowires confirmed their growth inside the pores of polycarbonate template. Single nanowires exhibits the semiconducting behavior according to I--V measurement and localized plasmon resonances.

Mechanism of efficiency of selected nanosystems intended for consolidation of porous materials

Over the past 20 years, the possible usage of disperse and colloid systems of organic consolidation agents as well as mineral systems with particle size in nanodimensions in the context of cultural heritage care has been examined. Nanomaterials, with particle size of up to 1 mu m whose properties are at a certain intersection between properties at the level of molecules and mass are the subject-matter of extensive scientific research for their positive physical and mechanical properties such as high chemical efficiency, excellent plastic, consolidation and diffusion properties, low sintering temperature, cleaning capabilities and others. Nanomaterials whose consolidation efficiency has been tested by experimental research, include, in particular, hydroxide nanodispersions. The article summarises basic conditions for application and principles of efficiency of selected nanosystems for consolidation of historic lime-based porous materials, i.e. in particular lime-based plasters that form integral part of historic buildingsNAKI [DG16P02M055

Analysis of ads in the selected segment from perspective of Logos, Pathos, Ethos

Předložená diplomová práce se zabývá apely v reklamních spotech z pohledu Logos Pathos Ethos. Cílem práce je analyzovat reklamní obsahy s finanční tématikou předních bankovních institucí působících na českém trhu. Jedná se o Fio Banku, Air Bank, Raiffeisenbank ČR, ČSOB a Monetu Money Bank. Jádrem práce je zjistit, jakým způsobem realizují svá reklamní sdělení a jaký dopad mohou mít na cílové publikum. Především řeší využívání reklamních apelů z pohledu informačního, emocionálního a autoritativního typu sdělení. Výzkum byl realizován prostřednictvím kvantitativní obsahové analýzy reklamních spotů jednotlivých bank. Výsledky a konečné výstupy výzkumu jsou obsaženy ve výzkumné zprávě.ObhájenoThe presented master's thesis deals with appeals in advertising spots from the perspective of Logos Pathos Ethos. The aim of the work is to analyze the financial-themed advertising content of leading banking institutions operating on the Czech market. These are Fio Bank, Air Bank, Raiffeisenbank ČR, ČSOB and Moneta Money Bank. The core of the work is to find out how they implement their advertising messages and what impact they can have on the target audience. Above all, it deals with the use of advertising appeals from the perspective of informational, emotional and authoritative types of messages. The research was carried out through a quantitative content analysis of advertising spots of individual banks. The results and final outputs of the research are contained in the research report

Technology of preparation of barium and magnesium hydroxide nanodispersion and possibilities of their use in monument care

An application of hydroxide nanoparticles in preservation of cultural heritage attracted great interest. The nanodispersions of calcium, magnesium or barium hydroxides exhibit high performance in consolidation abilities. In this work we focused on preparation of magnesium and barium hydroxide nanoparticles. For the synthetic procedure we used acetate precursors and sodium hydroxide. Obtained particles were dispersed in 2-propanol. Hydroxide nanoparticles were characterized by powder X-Ray diffraction, infrared spectroscopy and scanning electron microscopy. It was observed that smaller particles were achieved in case of magnesium hydroxide. Presented work demonstrates that this reaction procedure can be applied for preparation of materials used in cultural heritage preservation.NAKI research project "Development and Research of Materials, Methods and Technologies for the Restoration, Preservation and Strengthening of Historic Masonry Constructions and Surfaces and Systems of Preventive Conservation of Cultural Heritage Buildings [DG16P02M055

Paraloid B72 nanodispersion preparation technology and its possibilities for use in the monument care

The paper summarizes the results of laboratory research on acrylate polymer Paraloid B72, the use of which is widespread in the consolidation and protection of historical materials. The aim of laboratory research was primarily to analyze the possibilities of modifying particle sizes, given that this material characteristic plays an important role in the penetration process and hence the effectiveness of the consolidator. The contribution shows and compares the basic properties of the tested dispersions of Paraloid B72. The tested polymer system has a smaller particle size and it is possible to assume the possibility of proper use in monument care.NAKI [DG16P02M055

The power of non-hydrolytic sol-gel chemistry: A review

This review is devoted to non-hydrolytic sol-gel chemistry. During the last 25 years, non-hydrolytic sol-gel (NHSG) techniques were found to be attractive and versatile methods for the preparation of oxide materials. Compared to conventional hydrolytic approaches, the NHSG route allows reaction control at the atomic scale resulting in homogeneous and well defined products. Due to these features and the ability to design specific materials, the products of NHSG reactions have been used in many fields of application. The aim of this review is to present an overview of NHSG research in recent years with an emphasis on the syntheses of mixed oxides, silicates and phosphates. The first part of the review highlights well known condensation reactions with some deeper insights into their mechanism and also presents novel condensation reactions established in NHSG chemistry in recent years. In the second section we discuss porosity control and novel compositions of selected materials. In the last part, the applications of NHSG derived materials as heterogeneous catalysts and supports, luminescent materials and electrode materials in Li-ion batteries are described. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.LO1504, MŠMT, Ministerstvo Školství, Mládeže a Tělovýchovy; LQ1601, MŠMT, Ministerstvo Školství, Mládeže a TělovýchovyMinistry of Education, Youth and Sports of the Czech Republic under the project CEITEC [LQ1601]; Ministry of Education, Youth and Sports of the Czech Republic under Program NPU I [LO1504]; Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio); Energy Frontier Research Center - U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences [DESC0000997]; DOE BES [DE-FG02-01ER15259

Nanotechnology in the cultural heritage - influence of nanospensions adopted by nanoparticles of TiO2 for cleaning the surface of historical plasters

The continuous development of nanostructure and the study of physico - chemical processes in the nanometer range lead to new methods that can slow down the degradation processes of a work of art, or even restore damage caused, for example, by an inappropriate restoration process. The use of nanosuspensions based on calcium hydroxide is probably the most widespread application of nanomaterials in heritage care, especially in the field of hardening of lime building materials (plaster, limestone, etc.). In combination with titanium dioxide, it should be a successful suspension in the fight against biological agents, surface contamination or in the protection of UV-resistant building materials.NAKI II [DG16P02M005

Comparison of selected physical properties of tested nanosuspensions - The results of the experimental research of the degree of sedimentation and the depth of penetration in reference materials in laboratory conditions

Between used and already verified technologies for the reinforcement of plasters mainly include nanosuspension containing nanoparticles of calcium hydroxide and nanomaterials based on magnesium hydroxide and barium carbonate [1]. Individual lime nanosuspension, which consists of nanoparticles of calcium hydroxide, are dispersed in an alcoholic environment and they differ from each concentration and type of alcohol. When the material is cured, carbonatation occurs, as well as in the case of fresh plaster, where the calcium hydroxide reacts with atmospheric carbon dioxide to produce calcium carbonate. Due to the deposition of calcium carbonate in the damaged material, occurs re-strengthened ties and its hardening. The undoubted advantage of the consolidation of plaster using nanolime is the low number of impregnation cycles, where after a few applications nanosuspension occurs to the reinforcement of degraded material.NAKI II [DG16P02M005

Facile microwave-assisted synthesis of casein derived carbon nanodots

Belonging to the carbon family, yet standing apart, carbon nanodots are materials with excellent properties. Among them, they are well known for their attractive optical properties. The insight into this outstanding strength has resulted in the discovery of unique design of materials. These nanodots can be prepared via various methods to obtain a good optical response. In our research, we synthesized them using a microwave reactor, which is simple, fast and productive. As a carbon source casein, a low-cost precursor was used. Since this is a protein composed of amino acids, no additional passivation was required. Polyvinylpyrrolidone was used as a stabilizer for the nanodots. The synthesis was carried out at 200 °C for 30 minutes. The color change of the resulting solution to orange brown indicates the formation of carbon nanodots. These nanodots were filtered and dialyzed to be used for further characterizations. The carbon nanodots were spherical with the average size of about 9.7 nm. They showed a strong blue emission in the visible region with an appreciable quantum yield. One of the important characteristics of this method is the availability of reasonably good product yield. The prepared carbon nanodots have potential applications in the field of electrochemistry, optoelectronics and biological imaging. © 2021 TANGER Ltd., Ostrava.Ministry of Education, Youth and Sports of the Czech Republic Program-DKRVO [RP/CPS/2020/006]RP/CPS/2020/00

Sonochemical synthesis of Gd3+ doped CoFe2O4 spinel ferrite nanoparticles and its physical properties

In this work, a facile and green method for gadolinium doped cobalt ferrite (CoFe2−xGdxO4; x = 0.00, 0.05, 0.10, 0.15, 0.20) nanoparticles by using ultrasonic irradiation was reported. The impact of Gd3+ substitution on the structural, magnetic, dielectric and electrical properties of cobalt ferrite nanoparticles was evaluated. The sonochemically synthesized spinel ferrite nanoparticles were characterized by X-ray Diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM). X-ray diffraction (XRD) study confirmed the formation of single phase spinel ferrite of CoFe2−xGdxO4 nanoparticles. XRD results also revealed that ultrasonic irradiation seems to be favourable to achieve highly crystalline single crystal phase gadolinium doped cobalt ferrite nanoparticles without any post annealing process. Fourier Transform Infrared and Raman Spectra confirmed the formation of spinel ferrite crystal structure. X-ray photoelectron spectroscopy revealed the impact of Gd3+ substitution in CoFe2O4 nanoparticles on cation distribution at the tetrahedral and octahedral site in spinel ferrite crystal system. The electrical properties showed that the Gd3+ doped cobalt ferrite (CoFe2−xGdxO4; x = 0.20) exhibit enhanced dielectric constant (277 at 100 Hz) and ac conductivity (20.2 × 10−9 S/cm at 100 Hz). The modulus spectroscopy demonstrated the impact of Gd3+ substitution in cobalt ferrite nanoparticles on grain boundary relaxation time, capacitance and resistance. Magnetic property measurement revealed that the coercivity decreases with Gd3+ substitution from 234.32 Oe (x = 0.00) to 12.60 Oe (x = 0.05) and further increases from 12.60 Oe (x = 0.05) to 68.62 Oe (x = 0.20). Moreover, saturation magnetization decreases with Gd3+ substitution from 40.19 emu/g (x = 0.00) to 21.58 emu/g (x = 0.20). This work demonstrates that the grain size and cation distribution in Gd3+ doped cobalt ferrite nanoparticles synthesized by sonochemical method, is effective in controlling the structural, magnetic, and electrical properties, and can be find very promising applications. © 2017 Elsevier B.V.Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504