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STRAIN ENGINEERING OF THE ELECTRONIC STRUCTURE OF 2D MATERIALS
del Corro, Elena ; Peňa-Alvarez, M. ; Morales-García, A. ; Bouša, Milan ; Řáhová, Jaroslava ; Kavan, Ladislav ; Kalbáč, Martin ; Frank, Otakar
The research on graphene has attracted much attention since its first successful preparation in 2004. It possesses many unique properties, such as an extreme stiffness and strength, high electron mobility, ballistic transport even at room temperature, superior thermal conductivity and many others. The affection for graphene was followed swiftly by a keen interest in other two dimensional materials like transition metal dichalcogenides. As has been predicted and in part proven experimentally, the electronic properties of these materials can be modified by various means. The most common ones include covalent or non-covalent chemistry, electrochemical, gate or atomic doping, or quantum confinement. None of these methods has proven universal enough in terms of the devices' characteristics or scalability. However, another approach is known mechanical strain/stress, but experiments in that direction are scarce, in spite of their high promises.\nThe primary challenge consists in the understanding of the mechanical properties of 2D materials and in the ability to quantify the lattice deformation. Several techniques can be then used to apply strain to the specimens and thus to induce changes in their electronic structure. We will review their basic concepts and some of the examples so far documented experimentally and/or theoretically.
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Micro-electromembrane extraction across multiple aqueous and organic phases for selective pretreatment of raw biological samples
Kubáň, Pavel ; Boček, Petr ; Seip, K. F. ; Gjelstad, A. ; Pedersen-Bjergaard, S.
Micro-electromembrane extraction (μ-EME) across multiple aqueous and organic\nsolutions was developed for selective extractions of various analytes from untreated\nbiological samples. The novel approach requires μL volumes of samples and organic\nsolvents, which form consecutive immiscible plugs in a transparent polymeric capillary\nand the extraction process is accelerated by application of d.c. voltage. Number of the\nplugs, their composition, volume and sequence in the extraction capillary can be chosen\nspecifically for each particular application and high variability and selectivity of the\nextraction process can be achieved. In this contribution, we demonstrate suitability of\na five-phase μ-EME system for simultaneous extractions of cations and anions from\nurine and for selective extractions of basic analytes based on their acid-base strength\nfrom plasma.
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ELECTRON BEAM REMELTING OF PLASMA SPRAYED ALUMINA COATINGS
Matějíček, Jiří ; Veverka, J. ; Čížek, J. ; Kouřil, J.
Plasma sprayed alumina coatings find numerous applications in various fields, where they enhance the properties of the base material. Examples include thermal barriers, wear resistance, electrical insulation, and diffusion and corrosion barriers. A typical structure of plasma sprayed coatings, containing a multitude of voids and imperfectly bonded interfaces, gives them unique properties - particularly low thermal conductivity, high strain tolerance, etc. However, for certain applications such as permeation barriers or wear resistance, these voids may be detrimental.\nThis paper reports on the first experiments with remelting of plasma sprayed alumina coatings by electron beam technology, with the purpose of densifying the coatings and thereby eliminating the voids. Throughout the study, several parameters of the e-beam device were varied - beam current, traverse velocity and number of passes. The treated coatings were observed by light and electron microscopy and the thickness, structure and surface morphology of the remelted layer were determined and correlated with the process parameters. Based on the first series of experiments, the e-beam settings leading to dense and smooth remelted layer of sufficient thickness were obtained. In this layer, a change of phase composition and a marked increase in hardness were observed.\n
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San Minn (or) An Artist who prefer creating and paintings than his life
Zeya, Pyin Nyar ; JANEČEK, Vít (advisor) ; VOJTĚCHOVSKÝ, Miloš (referee)
No one can control a painter artist’s freely thoughts and ideas and although his paintings were under the high pressure and banned by force, the artistic value of his materials never go down. So that I am writing this paper.
He, San Minn has broken out the mainstream of Burmese painting field, he never made business paintings as well. He keeps his belief on the art of paints and he is always finding for the new way to make his paintings. His materials are very different from other Burmese painter artists’ materials. His style is unique in Burmese paintings. So I can get a chance to study of his style, ideas, ways of thinking and his determination on the art works.
My paper can show a painter artist’s life who grew up under the military rule for 50 years and the situation and history of Burmese painting field. Then not only people who are studying the painting subject, but also other people can know about the subject of Burmese painting and field of artists. I dare say that my paper must be colorful and fruitful.
As a painter artist, it seems that he wants his audience to feel his materials but he rare to show his real life behind the pictures. For me, I can get a chance to know about his real life for my thesis paper.
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Thesis Statement
My thesis can be useful for everybody who is interested in Burmese contemporary art field.
This is the biggest chance to read about one of the most famous, important and significant artists and art movements of Burma. His paintings are reflecting his journey through over 40 years of censorship, but he was not afraid to tackle political and social issues.
Many of San Minn's art works are based on autobiographical, making sharp social commentary on the popular culture, social values and scenario circumstances where he has lived in.
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Nutrition of pregnant - reccomendation and reality
FAJMONOVÁ, Simona
For my bachelor thesis I have chosen the theme : Nutrition of pregnant women recommendations and reality. The theoretical part includes the specifics of nutrition in preconception period and pregnancy, risk groups of pregnant women, high-risk behavior and a chapter about dietary supplementation in pregnancy. Pregnancy is an important period in a woman's life. The changes that accompany pregnancy also impose increased demands on the supply of the body with nutrients. I have chosen the method of a survey for the processing of the research part of my thesis. The practical part includes the results of the survey, which was attended by 80 women in the 7th-9th month of pregnancy. The questionnaire asked for basic information besides the weight, height and weight gain in pregnancy, also eating habits, fluid intake, inadequate habits (alcohol, smoking), use of dietary supplements, awareness of pregnant women and their physical activity. The questionnaires were processed in Microsoft Excel using tables and graphs. All collected pieces of information about dietary habits were compared with the recommendations for pregnant women. The aim of this thesis was to find out what is the reality of eating habits of pregnant women compared with recommendations. Another aim was to determine, whether pregnant women are well informed about the nutrition recommendations during their pregnancy and where they get the information from. Further aim was to explore, whether pregnant women use nutritional supplements before or during pregnancy and what kind of them. The last aim was to determine some of the bad habits during pregnancy (e.g. alcohol , smoking). The results of the questionnaire survey showed that by the majority of pregnant women the reality and recommendations coincided in water intake and beverage preference. Most of them preferred water or tea. Coffee consumption was also by the majority of them problem-free. Eating meat and eggs corresponded with the recommendations for a large group of respondents. As for legumes, fish and fish products, their consumption corresponded with the recommendations by only about half of the women. Eating fruits and vegetables were in the majority of pregnant women unfortunately insufficient as well as the consumption of milk and dairy products, nuts and seeds. It would be very appropriate to increase consumption of these groups of food. Conversely, the consumption of sausages and sweets, which turned out to be more frequent, should be reduced . Most women were well informed about the nutrition recommendations during their pregnancy, in most cases from the media or pregnancy counseling from a doctor. Here, I would suggest creating a website for pregnant women offering really reliable information. Nutritional supplements related to pregnancy were used by about half of the respondents. Only less than a half of the surveyed women supplemented folic acid in preconception period. I would suggest to create some information leaflets about the suitability of folic acid supplementation in preconception period and place them in the gynecological outpatient's clinics . Pregnant women ordinarily didn't smoke and consume alcohol. Occasional alcohol consumption stated 14 % of women. It seems that women are informed enough about the risk of smoking and alcohol consumption.
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Nutrition and other factors, which have influence on the formation and prevention of colorectal cancer
BENEŠOVÁ, Lucie
The full title of my bachelor thesis is Nutrition and Other Factors Influencing the Development and Prevention of Colorectal Cancer. In the theory section of the paper I have concentrated on clarifying the term "colorectal cancer", its epidemiology, and furthermore, on diet and other risk factors concerning the development and prevention of this disease. In this theory section I have included information about screening tests for occult bleeding. I have addressed the key objectives in the practical section of the thesis. I had set two key objectives. The first was to research how well respondents were informed concerning diets beneficial in the prevention of colorectal cancer, and the second objective concentrated on assessing the respondents' behaviour in relation to the information they had acquired. The research questions were formulated thus: "How well are people informed about diets aimed at preventing colorectal cancer?" and "Do people behave according to information thus gained?" The qualitative research method a semi-structured interview was used for the research section. Ten male respondents over the age of 45 took part in the interview. Five of these males were Dr Ilona Paseková's outpatients all with a genetic disposition to colorectal cancer, with most experiencing problems related to this disease. The other five respondents were without any predispositions. After receiving answers to the questions posed to the respondents, I wanted to compare both groups in order to ascertain whether those with a genetic predisposition showed a greater interest in this disease. Furthermore, I wanted to find out whether those respondents were actively seeking information concerning the prevention or treatment of colorectal and anal cancer. All those interviewed were very open and willing to answer questions. Collection of data was carried out from January 2014 to March 2014. The conclusions of this thesis show that public awareness of colorectal cancer and its prevention is inadequate. Public awareness of diets beneficial in the prevention of colorectal cancer is markedly poor, even among high-risk respondents. Having observed this lack of awareness, I proceeded to question respondents as to their dietary and lifestyle habits. Furthermore, the respondents were asked if they were aware that colorectal cancer screening was available in the Czech Republic. The results showed that some respondents, however unaware of diets beneficial in the prevention of colorectal cancer, follow a healthy diet, thus fulfilling dieticians' recommendations concerning the prevention of this disease. When asked about preventive foods, respondents most often mentioned brassicas broccoli and cabbage, etc. Conversely, the most often mentioned foods said to increase the risk of disease were smoked meat and red meat. One respondent mentioned the preventive affects of shark cartilage. I was very surprised by this assertion and subsequently searched the internet for information relating to shark cartilage. To my surprise, I found that the respondent was indeed not mistaken, and that statements to that effect can be found on websites promoting dietary supplements containing shark cartilage extract. According to these sources sharks do not suffer from cancer and therefore, their cartilage is closely studied and dietary supplements containing its extracts are produced. Furthermore, I intended to compare two groups of respondents those with genetic dispositions and those without. After carrying out the respective interviews, their comparison appeared to be futile. In both groups I identified respondents who followed a healthy diet and lifestyle as well as those who did not. I found that there is no relation between high-risk habits and predisposition to colorectal cancer. Whether a respondent with such a predisposition decided to follow a healthy diet or change his dietary habits and lifestyle or not was purely a question of his personal preferences.
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Sorption and Stabilization of Metals/Mettalloids by Innovative Synthesized Sorbent Amochar.
Ouředníček, P. ; Trakal, L. ; Komárek, M. ; Pohořelý, Michael
Remediation of contaminated soil which is based on stabilization and immobilization of potential\nhazardous substance by sorption materials has been studied intensively nowadays. Biochar – activated organic carbon belongs to this group of stabilizing agents which can adsorb wide range of contaminants, including metals/metalloids. Surface area of the biochars is quite large in general and functional groups (e.g. COO–) can form chelates or alkaline elements on the surface, which is represented by cation exchange capacity. Altogether with the high pH values (7.00 – 10.00), biochars are quite effective sorbents and can adsorb metals/metalloids from the solution (ground water), especially in acidic soils (in the environments affected by intensive mining activities). Sorption\neffectiveness can be increased (especially for As (V) or Cr (VI) sorption) by modification of biochar by various types of secondary oxides. Innovative sorbent AMOchar (AMO + biochar) has been synthesized currently. The product was prepared by adding of biochar to the reaction solution during amorphous manganese oxide (AMO) synthesis. The AMOchar was formed mainly by Mn-oxalates which had coated surface of the pristine biochar. AMOchar composite was able to remove significantly higher amounts of various metal(loid)s from the solution despite the rather high pH of the material. Sorption effectiveness was high not only in case of Pb (II) sorption (almost 99%), and Cd(II) (51.2%), but also a very high amount of As(V), 91.4%. Additionally, both AMOchar composite was able to reduce Mn leaching. This can avoid potential post-contamination caused by the dissolution of less stable Mn-oxalates as observed in the pure AMO.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_22316111113040 - PDF
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Plasma spraying from liquids: plasma liquid interaction and coating build up
Tesař, Tomáš ; Mušálek, Radek ; Medřický, Jan ; Lukáč, František
Plasma spraying from liquid feedstocks is a rapidly developing field of thermal spraying since the coatings prepared from liquids exhibit some unique features, such as high hardness, thermal shock resistance or low thermal and electric conductivity. The key factor influencing the final coating character and properties is the input material which may be in the form of a suspension or a solution. Parameters of the selected suspension (solids concentration, viscosity, surface tension, chemical composition, etc.) or solution (concentration, etc.) determine its interaction with the plasma jet which strongly influences the coating buildup. This proceeding introduces the problematics of the interaction between the liquid feedstock material with the plasma jet and presents the way of evaluation of the coating buildup.
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