According to the 2019 Canadian infrastructure report card, a concerning amount of municipal infrastructure is in poor or very poor condition. The infrastructure in this condition requires immediate action for rehabilitation or replacement. For concrete infrastructure, an effective repair can extend its service life and ensure that the services it provides continue to meet the community expectations. However, unfavorable environmental factors such as repeated/cyclic loads and freezing and thawing cycles adversely affect the bond between substrate concrete and repair materials, which lowers the structural capacity of repaired structures. So far, researchers have found that bond strength of repair can be affected by surface roughness, surface moisture, chemical adhesion or cohesion, curing regime, properties of substrate and repair materials, use of bond agent, and curing regimes. These findings are mostly based on the studies that focused on cold-jointed cylinders or beams, but in real-life repair situations, repairs of beams or slabs are located at either tension or compression side of the structure. Currently, there is no comprehensive study that investigates the bond of concrete repair under a combination of freezing and thawing and repeated/cyclic loading conditions. In addition, it is challenging to provide a rapid and non-destructive evaluation of the bond deterioration of repair materials. To address these issues systematically, this dissertation breaks the task into four phases. Phase (I) focuses on the development of an engineered “crack-free” repair mix that contains polypropylene (PP) fiber. A novel method is used to surface treat the PP fibers with supplementary cementitious materials. The effectiveness of surface-treating fibers for improved bond strength and reduced cracking is investigated. The compressive, tensile, and flexural strength of this engineered repair mix are determined and compared with two commercially available repair materials. The results from Phase I show that by adding 0.2% (by weight) Metakaolin-treated fibers into concrete mix, the compressive strength improves by up to 15.7% compared to mixes with untreated fibers. This study achieved a strength increase of 13.5% as compared to the reported 3.3% in other studies that use 25 times the amount of metakaolin used in this study. The experimental results confirm that at 0.2% dosage level, the use of novel surface treating technique is a cost-effective way to improve the strength of repair materials. Phase (II) focuses on characterizing the bond strength of various repair systems after freezing-thawing (FT) damage using both non-destructive and destructive methods. Two innovative sounding methods, which overcome the subjectivity of the traditional chain drag method, are used to evaluate FT damage non-destructively. In the experimental study, beams with a U-shaped cut are made to simulate conditions experienced by a concrete structure during a typical repair project. Three types of repair materials are used including cementitious repair concrete, cementitious repair mortar, and polymer-modified cementitious mortar. After up to 300 cycles of freeze-thaw exposure, resonant frequency and bond flexural strength of the prismatic specimens are determined. The empirical equations relating Non-destructive test (NDT) measurements and flexural bond strength of the repaired structures after freeze-thaw (FT) exposure are proposed. The results from Phase II show that the change in dynamic modulus of elasticity determined from NDTs agrees well with the change in other measurements including flexural bond strength, interfacial crack width, and mass loss after freeze-thaw exposure. In this study, linear relationships are established between dynamic modulus of elasticity and flexural bond strength for both cementitious and polymer-modified cementitious repair mortar with a coefficient of determination ranging between 0.87 and 0.95. The proposed empirical models can be used to predict bond flexural strength of repaired structures based on NDT measurement. Also, it was found that the samples repaired with polymer-modified cementitious mortar (Mix P) have superior FT resistance compared to other repaired samples. Phase (III) focuses on investigating the structural capacity and bond performance of repaired beams after cyclic/repeated loading. To accelerate the test process, a novel modified loading regime consisting of cycle groups of increasing cyclic/repeated stress amplitude is proposed. The models proposed by literature and current codes and standards are used to validate the results. Phase (IV) focuses on the development of the damage models for both individual and combined FT and cyclic loading exposure on repaired concrete structures. The results in phase III show the feasibility of using the Palmgren-Miner rule and Goodman linear model to estimate the fatigue life of repaired structures. This was confirmed within the context of this study. This study established the usefulness of using groups of increasing cyclic stress amplitude to accelerate the fatigue test process. The two-million cycle fatigue endurance limit estimated using cycle groups of Mix S (70.8%) was very similar to what was reported in the literature (71%) using the traditional time-consuming cyclic loading method. This study found that the formulas proposed by CSA 23.3 can effectively predict the moment resistance of both intact (control) and repaired RC beams. The ratio of experimental moment resistance values to its predictions ranges from 0.91 to 1.04. Based on the experimental results of previous three phases, an empirical model that predicted the fatigue service life of FT-damaged concrete structures is proposed. Future research requires a more comprehensive study on the FT performance of various polymer-modified cementitious mortars of different mix designs in repairing concrete structures. By increasing the number of tested specimens, a better relationship could be established between destructive and NDT methods. Future research is also required to explore the combined effect of FT and cyclic loading on repaired RC structures experimentally. / Graduate / 2023-03-22

The use of nanotechnology has become wide spread in all branches of science. Nanotechnology help us to understand microstructure and due to the world has started to produce new materials. One of many examples carbon nanotubes (CNTs). In diploma thesis I tried to find the way of successful introduction into concrete mixture. I was studying influence of CNTs and other nano particles and I was comparing them with referential samples (without CNTs). Also I tested the improvement of mechanical characteristics of concrete. The morphology of nano particles was studied using Scanning Electron Microscopy (SEM). The results show that introduction of nanoparticles to results in increasing strength and higher density. That is why High Performace Concrete so resistant and durable.

No description available.

PhD (Department of Biotechnology, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Tulbaghia violacea Harv. has found extensive uses in traditional medicine for the treatment of numerous ailments among which are tuberculosis, oesophageal cancer, diabetes and cardiovascular diseases. Current reports show that cardiovascular diseases are now the primary cause of mortality worldwide. Thus, the potential of T. violacea plant extracts against cardiovascular diseases should be explored. The objectives of this study were, (i) to conduct qualitative and quantitative preliminary phytochemical screening of T. violacea aqueous leaf extracts, (ii) to conduct Gas chromatography–mass spectrometry (GC-MS) analysis for screening of compounds present in the plant extract, (iii) to evaluate the antioxidant activity of the T. violacea crude extracts using the DPPH:1.1-diphenyl-2-picrylhydrazyl and ABTS: 2,2-azino-bis 3-ethylebenzthiazoline-6-sulfonic acid assays, (iv) to evaluate the antimicrobial activity of the T. violacea crude extracts using disk diffusion and Minimum inhibitory concentration/Minimum bactericidal concentration (MIC/MBC), (v) to evaluate the antithrombogenic properties of T. violacea crude extracts on polystyrene, (vi) to fabricate polycaprolactone (PCL) and PCL-T. violacea incorporated scaffolds, (vii) to evaluate the antithrombogenic properties of T. violacea crude extracts on the fabricated PCL and PCL-T. violacea fabricated scaffolds and, (viii) to evaluate the growth and differentiation of adipose derived stem cells (ADSCs) on the fabricated scaffolds. The qualitative and quantitative phytochemical screening was conducted using standard procedures. Folin-Ciocalteu method was used to evaluate both total phenolic content (TPC) and total tannin content (TTC), the Aluminium chloride method was used for total flavonoid content (TFC) and GC-MS was used to screen for compounds present in the plant extract. The antioxidant activity was evaluated using DPPH and ABTS and the antimicrobial activity was evaluated using disc diffusion and MIC/MBC assays. The antithrombogenic properties of the T. violacea aqueous leaf extracts was then evaluated using platelet activation and whole blood clotting kinetics on polystyrene discs which have been reported to induce platelet activation. The experiment was performed in the absence and presence of 100 and 1000 μg/ml T. violacea plant extracts for both the platelet activation study which used blood plasma and the whole blood clotting kinetics assay which used fresh whole blood. Platelet adhesion was evaluated using fluorescence microscopy and a scanning electron microscope (SEM) was used to evaluate their morphology. Three scaffolds designated as PCL, 10% Tvio and 15% Tvio were fabricated which consisted of a 10% PCL powder and 10% as well as 15% T. violacea aqueous plant extract with respect to the PCL powder weight. The scaffolds were then characterized using Fourier-transform infrared spectroscopy (FTIR) and Energy-dispersive x-ray spectroscopy (EDS). The scaffolds were then evaluated for their antithrombogenic properties in the presence and absence of 100 and 1000 μg/ml T. violacea plant extracts. Platelet adhesion was evaluated using a fluorescent microscope and the morphology was evaluated using SEM. For the cell study, adipose derived stem cells (ADSCs) were cultured on the designed scaffolds and evaluated for their toxicity, viability, adhesion, proliferation, morphology and differentiation into osteoblasts over a period of 3 weeks. Lactate dehydrogenase (LDH) assay was used for toxicity studies, alamar blue assay was used for viability, fluorescence microscopy was used to evaluate cellular adhesion and proliferation while the alkaline phosphate (ALP) assay was used to evaluate differentiation of the cells into osteoblasts. Cell morphology was evaluated using SEM. Phytochemical screening of the prepared T. violacea aqueous extract revealed the presence of terpenoids, flavonoids, cardiac glycosides, saponins, protein, phenols, tannins, carbohydrates and amino acids. This is the first study that has identified the presence of carbohydrates and amino acids in T. violacea aqueous leaf extracts. Different concentrations of 0.1, 1.0 and 10 mg/ml of plant extract were used to conduct the quantitative phytochemical screening assays. There was a concentration dependent increase in the amount of phenols, tannins and flavonoids as the concentration of the plant extracts increased. This was the first study that evaluated the total tannic content of T. violacea plant extracts. The amount of total phenols was higher than that of flavonoids and tannins at every concentration range studied followed by the total flavonoids and lastly total tannins. The GC-MS analysis showed the presence of 33 compounds among which were 2,4 – Dithiapentate - 2,2-dioxide, Cannabidiol, 2,4,5,7 –Tetrathiaoctane and 2,4,5,7 - Tetrathiaoctane 2-dioxide. The presence of sulphur compounds support the characteristic garlic-like smell as well as some of the biological activities of T. violacea plant extracts. The antioxidant activities based on DPPH (0.49 mg/ml) and ABTS (0.24 mg/ml) suggest that T. violacea can be used as potential antioxidant agents. For the antimicrobial activity using disc diffusion, the extracts exhibited appreciable antibacterial activities against Bacillus subtilis, Serratia marcescens, Staphylococcus aureus and S. epidermidis. The highest zone of inhibition was observed for S. epidermidis at 19.50 ± 0.87 mm. The MIC results revealed that the plant extract of T. violacea was moderately active against B. subtilis, S. aureus, S. epidermidis, E. coli, and S. marcescens with MIC value of 2.5 mg/ml. However, the antimicrobial effect of the extract on S. epidermidis was bactericidal when compared to the bacteriostatic effect on the other active microorganisms. The antithrombogenic results on the polystyrene discs showed a significant reduction in the number of platelets that adhered on the polystyrene surfaces treated with plasma mixed with 100 μg/ml of plant extract when compared to the untreated control and the 1000 μg/ml treatment. For the 1000 μg/ml treatment, there was a significant increase in the number of platelets that adhered to polystyrene surfaces. These results were confirmed by the fluorescence and SEM results which showed a higher platelet count for the 1000 μg/ml treatment when compared to the other groups. The whole blood clotting kinetics study showed delayed blood clotting with the 100 μg/ml treatment over a period of 60 min when compared to the untreated control and the 1000 μg/ml treatment. These results correspond with the lower platelet adhesion observation and thus confirm the anticlotting properties of T. violacea aqueous leaf extracts at lower concentrations. The mean diameter of the scaffolds was recorded on the SEM as 275.60 ± 60.65 nm, 193 ± 30 nm and 537 ± 138 nm for the PCL, 10% Tvio and 15% Tvio scaffolds, respectively. The FTIR spectrum revealed the presence of amide groups as well hydroxyl O–H stretching groups which were the characteristic groups for the presence of T. violacea plant extracts in the polycaprolactone. The EDS results showed the presence of potassium, chlorine and sulphur compounds which were only present in the T. violacea scaffolds in addition to the carbon, oxygen and silicon observed in the PCL scaffold. The fabricated scaffolds were then used to evaluate platelet adhesion and activation on blood plasma in the absence and presence of 100 and 1000 μg/ml T. violacea aqueous leaf extracts. The results showed that the 10% Tvio scaffold was more effective in inhibiting platelet adhesion and activation at every treatment group especially when plasma was used in the absence of T. violacea plant extracts. A similar observation to the polystyrene study was observed were addition of 1000 μg/ml of plant extract resulted in the highest number of activated platelets. The study suggests the potential of the 10% Tvio scaffold in the prevention of platelet adhesion and aggregation. The in vitro cell adhesion, proliferation and differentiation of adipose derived stem cells (ADSCs) on the fabricated T. violacea loaded PCL nanofibers was then evaluated. The LDH assay illustrated less activity on the 10% Tvio scaffold when compared to PCL and 15% Tvio scaffolds however, none of the scaffolds were considered as toxic. The alamar blue assay was used for viability after 4 and 7 days of culture. The results showed a significant increase in cell viability for all scaffolds from day 4 to day 7 with the 10% Tvio scaffold having the highest overall cell viability for both day 4 and day 7 of cell cultures. Immunofluorescence staining was then used to count the number of cells using DAPI (4′,6-diamidino-2-phenylindole) stained images and illustrated that the T. violacea incorporated scaffolds supported better cell growth compared to the PCL scaffold. Cell morphology on the T. violacea scaffolds was denser and spread out into cellular extensions when compared to the PCL scaffold after 7 days of cell culture, supporting the higher number of adhered cells from the fluorescence results. For the long term cell study after week 1 and 3, the ALP results showed a significant difference in ALP activity between week 1 and week 3 for all scaffolds. The highest ALP activity was observed for the 15% Tvio scaffolds which is a marker for initial phase of bone matrix deposition. The designed T. violacea scaffolds supported better cell growth compared to the PCL scaffold and their morphology was more spread out and covered the entire surface of the scaffolds after week 3. Lastly, the cell count and osteocalcin differentiation was more prominent on 10% Tvio scaffold indicating higher levels of the protein marker for bone formation. Thus, supporting the use of the 10% Tvio scaffold for long-term cell studies. In conclusion, the results of this study indicated that the aqueous extract of T. violacea is rich is phytochemicals and also possess a broad range of pharmaceutically important compounds which may be attributed to the high antioxidant and antimicrobial activities identified. The results from this study suggest that T. violacea aqueous extracts have antithrombogenic properties at lower concentrations. Scaffolds fabricated with the incorporation of T. violacea plant extract also confirm the potential antiplatelet activity of the fabricated 10% Tvio scaffold. The results also suggest the potential of the fabricated 10% Tvio scaffold to enhance cell adhesion, proliferation and differentiation over long-term cell studies. It can thus be recommended that T. violacea may be useful for tissue engineering applications and bone repair with prospects of preventing cardiovascular diseases associated with bone defects. This research study has provided the foundation for clinical evaluation and outlined the potential effects of T. violacea aqueous leaf extracts as a clinical drug.

Many transition metal oxides exhibit a Metal-Insulator Transition (MIT). This is an interesting phenomenon where the material undergoes a structural phase transition, and the electronic charge is redistributed in the crystal lattice. The crystallographic, optical, electrical, and magnetic properties are drastically changed when a material undergoes a MIT. Vanadium oxides are thermochromic materials, which means that the optical properties change with temperature, closely connected to the MIT. Vanadium sesquioxide (V2O3) experiences a MIT at the transition temperature (Tt) 160-170 K. Below the transition temperature, it is a monoclinic ferromagnetic insulator, and above the transition temperature it becomes a paramagnetic rhombohedral corundum-type metal. In the insulating phase, infrared (IR) light is transmitted, whereas in the metallic phase, IR light is reflected. The aim of this Master thesis is to improve the methodology to produce V2O3 thin films, characterize them, and study how different parameters affect the structural and optical properties of the film. V2O3 thin films were synthesized by sol-gel and deposited by spin-coating on sapphire substrates. Thereafter, the resulting films underwent an annealing process in a reducing atmosphere to achieve crystalline V2O3. The obtained crystal phase was examined by X-ray diffraction. The surface structure and morphology were studied with an optical microscope and scanning electron microscope. The optical transmittance in the IR region was examined by Fourier transform infrared spectroscopy. At last, a laser test was performed on one of the samples. In conclusion, a majority of the thin films consisted of polycrystalline V2O3. The MIT was studied with the optical hysteresis loop, which showed great difference among the different samples studied. The thin film that exhibited best optical properties showed a maximum transmission of 66 % below the Tt, and a minimum transmission of 6 % above the Tt. In comparison to this one, the other samples exhibited lower transmission and a decrease in Tt. This difference was attributed to the different morphologies and crystal orientations of the samples.

<p>The Earth–atmosphere energy balance is dictated by incoming solar radiation and outgoing thermal radiation with greenhouse gases (GHG) and aerosols playing a major role in this effect. The atmospheric abundance and properties of airborne particles and gases lead to the redistribution of radiative energy, resulting in a warming or cooling effect. However, the extent of this effect remains to be insufficiently constrained. Improved quantification and characterization of GHG and aerosols are important requirements to inform current climate models. High-precision instrumentation and thoughtful experimental strategies are necessary to yield various analytical measurement datasets, despite complex meteorological and environmental conditions. This dissertation focuses on the assessment of CO₂and atmospheric particles from aircraft-based measurements enabling representative and spatially sampling of local regions of interest.</p> <p>Chapter 1 provides introductory discussion on the atmospheric implication of GHG and aerosols on the climate and related uncertainties. Chapter 2 summarizes the employed experimental techniques for quantification of GHG and characterization of atmospheric particles. We relied on an aircraft platform equipped with an air turbulence probe for 3D wind vector calculation and a high-precision cavity ring-down spectrometer for the quantification of ambient CO₂, CH₄, and H2O_<em>v</em>. Furthermore, the simultaneous composition and morphological information of aerosol samples were assessed using complementary chemical imaging techniques. Chemical composition of elements with Z > 23 was determined using computer-controlled scanning electron microscopy with energy dispersive X-ray spectroscopy (CCSEM/EDX). Scanning transmission X-ray microscopy coupled with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS) was used to determined spatially resolved elemental specific molecular information present in atmospheric particles.</p> <p>Chapter 3 presents our study focused on the characterization of mixed mineral dust and biomass burning (BB) aerosols during an intensive burning event. We identified distinct particle types based on individual elemental contribution pre-, syn-, and post-burning event including highly carbonaceous (54–83%) particles, aged mineral dust (1–6%), and sulfur-containing particles (17–41%). X-ray spectromicroscopy techniques were used to characterize the internal chemical heterogeneity of individual BB particles and the morphology of soot inclusions, as well as changes in the particle organic volume fraction (OVF). An estimation method for particle component masses (i.e., organics, elemental carbon, and inorganics) inferred from STXM measurements was used to determine quantitative mixing state metrics based on entropy-derived diversity measures for particles acquired at different periods of the BB event. In general, there was a small difference in the particle-specific diversity among the samples (<em>D</em>_<em>α</em> = 1.3–1.8). However, the disparity from the bulk population diversity observed during the intense periods was found to have high values of <em>D</em>_<em>γ</em> = 2.5–2.9, while particles collected outside of the burning event displayed lower bulk diversity of <em>D</em>_<em>γ</em> = 1.5–2.0. Quantitative methods obtained from chemical imaging measurements presented here will serve to accurately characterize the evolution of mixed BB aerosols within urban environments.</p> <p>Chapter 4 follows the investigation of the physicochemical properties of atmospheric particles collected onboard a research aircraft flown over the Azores using offline spectromicroscopy techniques. Particles were collected within the marine boundary layer (MBL) and free troposphere (FT) comparing samples after long-range atmospheric transport episodes facilitated by dry intrusion (DI) events. The quantification of the OVF of individual particles derived from X-ray spectromicroscopy, which relates to the multi-component internal composition of individual particles, showed a factor of 2.06±0.16 and 1.11±0.04 increase in the MBL and FT, respectively, among DI samples. We show that supplying particle OVF into the <em>κ</em>-Köhler equation can be used as a good approximation of field-measured <em>in situ</em> CCN concentrations. We also report changes in the <em>κ</em> values in the MBL from <em>κ</em>_{MBL, non-DI} = 0.48 to <em>κ</em>_{MBL, DI} = 0.41, while changes in the FT result in <em>κ</em>_{FT, non-D}_I = 0.36 to <em>κ</em>_{FT, DI} = 0.33, which is consistent with enhancements in OVF followed by the DI episodes. Our observations suggest that the entrainment of particles from long-range continental sources alters the mixing state population and CCN properties of aerosol in the region.</p> <p>Chapter 5 discusses the identification and characterization of fine-mode primary biogenic atmospheric particles (PBAP) from the harvesting of crops. Particle samples were analyzed using complementary chemical imaging techniques to apportion the particle-type population based on their size, morphology, and composition. The contribution of PBAP in the size range of 0.15−1.25 μm is estimated to be 10−12% of ∼39,000 analyzed particles. In addition, particle viscosity and phase state were inferred with X-ray spectromicroscopic analysis has shown that the fine-mode organic particles collected are viscous/semisolid (10²−10¹² Pa s) while the majority of PBAP fragments are solid (>10¹²Pa s). The observation of submicrometer, solid carbonaceous fragments of biogenic origin have implications for the regional CCN and ice nuclei budget. Therefore, the seasonal harvesting of crops may play an important, yet unrecognized, role in regional cloud formation and climate.</p> <p>Chapter 6  explores the measurements and quantification of latent heat, sensible heat, and CO₂ fluxes among different land covers in the surrounding area of urban regions using airborne flux techniques. Cities account for the majority of the global CO₂ emissions due to the consumption of energy, resources, infrastructure, and transportation demands. Accordingly, the accurate quantification of these emissions, with exceptional precision, is necessary so that progress towards emission reduction can be monitored. However, a major challenge in quantifying urban emission estimates arises from accurate background emission definitions and apportionment of emission sources in complex urban environments. Airborne eddy covariance measurements were performed to quantify the bidirectional exchange of latent heat, sensible heat, and CO₂ fluxes in the upwind region of Indianapolis within an active biosphere. Here, we observed differences in fluxes across different days and land covers (e.g., corn, soybean, and forests) allowing us to understand the impact of seasonal variability in urban emissions during the full growing season. These experiments illustrate the capability of a research aircraft to perform technically challenging near-direct measurements of atmosphere–surface exchange over local and regional scales.</p> <p>Chapter 7 presents a new method to spatially allocate airborne mass balance CO₂ emissions. We performed seven aircraft measurements downwind of New York City (NYC) quantifying CO₂ emissions during the non-growing seasons of 2018–2020. A series of prior inventories and footprint transport models were used to account for flux contribution outside the area of interest and attribute emission sources within policy-relevant boundaries of the five boroughs encompassing NYC and then employ the modeled enhancement fraction (Φ) to the bulk emission observations from the mass balance approach. Here, we calculated a campaign-averaged source apportioned mass balance CO₂ emission rate of 56±24 kmol/s. The performance and accuracy of this approach were evaluated against other published works including inventory scaling and inverse modeling, yielding a difference of 5.1% with respect to the average emission rate reported by the two complementary approaches. Utilizing the ensemble of emissions inventories and transport models, we also evaluated the overall sources of variability induced by the prior (1.7%), the transport (4.2%), and the daily variability (42.0%). This approach provides a solution to interpreting aircraft-based mass balance results in complex emission environments.</p> <p>Chapter 8 concludes with a brief discussion of technological advances and research outlooks for X-ray spectromicroscopy analysis on atmospheric particles and the quantification of GHG. Opportunities for future applications and novel development of CCSEM/EDX and STXM/NEXAFS to substantially extend the instrument capabilities and improve our understanding of the physicochemical properties of individual atmospheric particles. Chapter 8 also discusses recent developments in satellite-based CO₂ monitoring to complement direct airborne observations. In recent years, significant progress has been made in satellite-based measurements of CO₂ to reveal the spatio-temporal variation in atmospheric CO₂ concentration. The column-averaged dry air CO₂ mole have reached an accuracy of ~1 ppm with a spatial resolution of less than 4 km. Furthermore, column-averaged retrievals can be used to detect and estimate the surface CO₂ fluxes in an active biosphere, quantify anthropogenic emissions over megacities, and monitor the transport of fossil fuel plumes across different continents and seasons.</p>

Цель магистерской диссертации состояла в изучении влияния режимов анодирования и условий последующей температурной обработки на структурные и люминесцентные свойства нанопористого оксида алюминия. Рассмотрены основные структурные особенности анодированного оксида алюминия (АОА) и методики получения его упорядоченных структур, его области применения и люминесцентные свойства. Успешно синтезирована серия из 20 образцов АОА в условиях варьирования электрохимических, временных и температурных режимов. Проведена аттестация полученных образцов методами сканирующей электронной микроскопии и рентгеноструктурного анализа. Проведена статистическая обработка полученных снимков с помощью анализатора изображений SIAMS 700. Проанализированы зависимости среднего диаметра пор от напряжения анодирования и толщины оксидного слоя от времени анодирования. Рассчитана средняя скорость роста АОА для гальвано- и потенциостатических режимов. Изучены особенности и трансформация спектров диффузного отражения, фото- и катодолюминесценции образцов АОА в зависимости от условий электрохимического окисления и последующей термообработки. На основе сравнительного анализа литературных данных проведена идентификация активных центров свечения собственной (F-, F+-центры) и примесной (комплексы C2O42- и HC2O4-, ионы Cr3+ и Mn4+) природы. Рассмотрены перспективы дальнейших исследований и возможных применений синтезируемых мембран анодированного оксида алюминия. / The aim of this Master paper is to study the effect of anodizing modes and subsequent temperature treatment on structural and luminescent properties of nanoporous anodic alumina. Structural features of anodic aluminum oxide (AAO), its ordered structures obtaining methods, fields of application and luminescent properties were discussed. A series of twenty samples varying electrochemical, time and temperature regimes was obtained. Obtained samples were characterized by scanning electron microscopy and X-ray diffraction analysis techniques. Images of structures were quantitavely analyzed using SIAMS 700 software package. It was studied how average pore diameter and oxide layer thickness depend on anodizing voltage and duration accordingly. Average AAO growth rate for galvanostatic and potentiostaic modes was calculated. Features and transformation of diffuse reflection, photo- and cathodoluminescence of AAO samples obtained under various electrochemical oxidation conditions and after subsequent temperature treatment were studied. Active emission centers of intrinsic (F-, F+-centers) and impurity (C2O42- and HC2O4- complexes, Cr3+ и Mn4+ ions) nature were identified on the basis of literature data comparative analysis. Further promising directions of studies and possible applications of synthesized AAO membranes were discussed.

Due to the study basic structural features of ultrafine ceramics, using the scanning electron microscopy method, were identified. Dependency of particle sizes on thermal treatment modes was determined, and average size of the sample grains was determined due to statistical processing of the SEM images, using hardware and software image analysis package SIAMS 700. It has been established that photoluminescent properties of single-crystalline samples under the study correspond to the publicly available literature data. Photoluminescence spectra were measured after sample finishing and dependence of optical absorption on exposure dose was identified. The ultrafine ceramic FL was examined and comparison study of the resulting parameters with a single-crystalline sample was carried out. Excitation and emission spectra under various modes of ceramic synthesis were also produced. This study makes it possible to consider ultrafine ceramics as a non-conventional material for high-dose measurements. / В результате исследования были выявлены основные структурные особенности ультрадисперсной керамики методом растровой электронной микроскопии. Определена зависимость размеров частиц от режимов термической обработки, а так же найден средний размер зерен образцов за счет проведения статистической обработки изображений РЭМ на программно-аппаратном комплексе анализа изображений SIAMS 700. Установлено, что фотолюминесцентные свойства исследуемых монокристаллических образцов соответствуют общеизвестным литературными данными. Измерены спектры фотолюминесценции после полировки образцов и найдена зависимость оптического поглощения от дозы облучения. Рассмотрена ФЛ ультрадисперсной керамики и проведен сравнительный анализ полученных параметров с монокристаллическим образцом. Так же получены спектры возбуждения и излучения при различных режимах синтеза керамики. Данные исследования позволяют рассматривать ультрадисперсную керамику как перспективный материал для высокодозных измерений.

Объект изучения – модуль плазмохимического травления и осаждения на базе нанотехнологического комплекса Нанофаб-100. Цель работы — плазмохимический синтез тонких покрытий на основе нитридов алюминия и титана. Методы исследования: плазмостимулированное химическое осаждение из газовой фазы, электрохимическое окисление, плазменное азотирование, сканирующая электронная и атомно-силовая микроскопия, оптическая спектроскопия, наноиндентирование. В результате исследования разработана методика синтеза нитрида алюминия на установке плазмохимического синтеза. Синтезированы тонкие пленки нитрида алюминия толщиной 50-200 нм. Продемонстрирована возможность получения наноточек нитрида алюминия. С помощью плазмохимического азотирования модифицирована поверхность металлического титана с увеличением твердости в 4 раза. Показана возможность получения нанотубулярных структур нитрида титана, являющихся перспективными в целях создания электронных устройств, фотокаталитических ячеек и др. Результаты работы отражены в тезисах докладов III Международной молодежной научной конференции «Физика. Технологии. Инновации. ФТИ-2016». / The object of this study is the module of plasma chemical etching and deposition based on nanotechnology complex Nanofab-100. The goal of the current paper is the plasma-chemical synthesis of thin coatings based on aluminum and titanium nitrides. As a result of the research, a technological map for the routine of the plasma-chemical synthesis and a technique for obtaining nanomaterials on the example of aluminum nitride have been developed. There were synthesized thin films of aluminum nitride with 50-200 nm thickness. The possibility of synthesis nano-dots of AlN is demonstrated. The surface of metallic titanium has been modified with an increase in hardness by 4 times using plasma-assisted nitriding process. The possibility of obtaining nanotubular structures of titanium nitride, which are promising for microelectronic and photocatalysis, is shown. The results of the work are reported in abstracts of the III International Youth Scientific Conference «Physics. Technologies. Innovation. FTI-2016».

Основными технологическими и трудно определяемыми примесями в h-BN выступают углерод и кислород. На производстве возникает необходимость в контроле качества с высоким пространственным разрешением как отдельных нанослоев h-BN, так и готовых гетероструктур на его основе. Целью работы является разработка способа неразрушающего контроля дефектности и примесного состава тонких слоев h-BN методами комбинационного рассеяния света и катодолюминесцентной спектрометрии. Выполнен литературный обзор особенностей материала гексагонального нитрида бора и его люминесцентных свойств. Проведены измерения исследуемых образцов при помощи рамановского спектрометра, сканирующего электронного микроскопа с катодолюминесцентной приставкой и электронно-зондового микроанализатора. Выполнен анализ полученных результатов. / The main technological and difficult-to-determine impurities in h-BN are carbon and oxygen. In production, there is a need for quality control with high spatial resolution of both individual h-BN nanolayers and heterostructures based on it. The aim of the work is to develop a method for non-destructive testing of the defects and impurity composition of h-BN thin layers by Raman scattering and cathodoluminescence spectrometry. A literature review of the features of the material of hexagonal boron nitride and its luminescent properties is performed. The samples were measured using a Raman spectrometer, a scanning electron microscope with a cathodoluminescent attachment, and an electron probe microanalyzer. The analysis of the obtained results is performed. Areas of application: diagnostics and quality control.