Spelling suggestions: "subject:"difuze""
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Analýza časoprostorové variability koncentrací ozonu v Jizerských horách / Temporal and spatial analysis of ozone in the Jizerske hory Mts.Stoklasová, Petra January 2012 (has links)
The aim of this thesis is to analyze and evaluate temporal and spatial patterns of concentrations of ambient ozone in the CHKO Jizerské hory. The Jizerské hory Mts. are an area where one of the highest concentrations of ambient ozone are measured every year and, therefore, our attention was focused on this area. The measurements were carried out between 2006 and 2010 at 13 sites (714-1000 m n. m.) in the CHKO Jizerské hory. From the input data, which were fortnightly average nitrate concentrations created on the filters of Ogawa passive samplers, fortnightly average concentrations of ambient ozone were computed using the empirical flow. Ambient ozone concentrations ranged from 13,8 ppb (year 2007) to 72,1 ppb (year 2006). From the five-year period under study defy the year 2006, when the highest concentrations of ambient ozone were measured. The lowest concentrations occurred in 2009. In all years, the concentrations of ambient ozone increased with increasing elevation and this gradient ranged from 2,7 to 4,6 ppb on 100 meters altitude. The accuracy and precision of measurement was very good (accuracy: R2 = 82 %; precision: R2 = 98 %). By multiple linear regression it was found, that ambient ozone concentration are influenced, in addition to the altitude, by ozone concentrations from previous...
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Stochastické modelování reakčně-difuzních procesů v biologii / Stochastické modelování reakčně-difuzních procesů v biologiiLipková, Jana January 2011 (has links)
Many biological processes can be described in terms of chemical reactions and diffusion. In this thesis, reaction-diusion mechanisms related to the formation of Turing patterns are studied. Necessary and sufficient conditions under which Turing instability occur is presented. Behaviour of Turing patterns is investigated with a use of deterministic approach, compartment-based stochastic simulation algorithm and molecular-based stochastic simulation algorithm.
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Studium antimikrobiálního efektu hroznových semenKoláčková, Ivana January 2017 (has links)
This paper is dedicated to gathering information about utilization of Vitis vinifera L. extracts, mainly grape seed extract (GSE), production of GSE in two variants (aqueous or methanol GSE) and description of its characteristics. Extract was rich in polyphenols (13462 mg/l GAE), measured by Folin-Ciocaltel method. Also 3615 mg/l GAE of flavonols was present in GSE. Antioxidant activity measured by DPPH method was high, 7978 mg/l GAE. Disc diffusion method was used for antimicrobial activity analysis. GSE's effect was tested on five common microorganisms. Results of the experiment show that GSE strongly inhibits growth of Bacillus cereus, Candida tropicalis and Enterococcus faecalis. However, it was not effective against Escherichia coli and Pseudomonas aeruginosa.
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Výpočet pokročilých difusních parametrů šedé hmoty mozku z DKI MRI obrazů / Calculation of advanced diffusion parameters in brain grey matter from DKI MRI imagesPánková, Olga January 2019 (has links)
Thesis named Calculation of advanced diffusion parameters in brain grey matter from DKI MRI images deals with processing of diffusion-weighted images from DKI. The thesis contains review of literature on principle of diffusion, influence of diffusion on MRI, calculation of DTI and DKI parameters and clinical application of diffusion-weighted maps with focus on grey matter. The thesis focuses on software tools for processing and pre-processing DTI and DKI. The practical part consisted of two sections. Two different softwares were used to calculate maps of diffusion parameters. Diffusion parameters from anatomical structure sunstantia nigra were compared between group of healthy controls and patients with Parkinson’s disease. This comparison did not show any statisticaly significant difference. In the second step, a script for creating diffusion maps in software Diffusinal Kurtosis Estimator was made.
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Rtg difrakce a difuzní rozpyl na Heuslerových slitinách / Rtg difrakce a difuzní rozpyl na Heuslerových slitináchCejpek, Petr January 2015 (has links)
Recently, Heusler alloys are studied for their interesting magnetic and electronic properties. These properties are strongly dependent on the crystallographic struc- ture. This work deals with Heusler alloys of the A2BC type. We have powder samples and single-crystaline samples for our study as well. An object of interest was a description of crystallographic structure of the samples, site occupation numbers of each type of atoms and their possible occupation disorder. Pow- der difraction and EXAFS have been measured on the powder samples. Clasical single-crystal diffractions has been meassured on the single-crystaline samples. In the case of a modulated structure in the samples, satelite difractions have been measured too. 1
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Variabilita koeficientů difuze vodní páry ve dřevě a její vliv na vlhkostní pole uvnitř vybrané konstrukceMaňák, Ondřej January 2015 (has links)
Hygroscopic properties of wood have significant impact on water vapor diffusion in this material. For the description of this phenomenon the water vapor permeability dependence on relative humidity or partial water vapor pressure can be used. Analytical expression of the diffusion coefficient of wood was modified in order to obtain values for the water vapor permeability. For the verification a cup method experiment at 25, 62.5 and 75% average relative humidity was performed and the results were compared to other researches. Calculated data formed the input of a numerical model, in which a stationary linear analysis with a nonlinear analysis was compared, taking the variability of diffusion properties into account in the construction details of vapor diffusion-open timber constructions. Differences in moisture fields were shown, which in some cases lead to underestimation of the risk of condensation or degradation of wood components in the building envelope, in other cases point to the actual better ability of wooden structures to divert moisture from the interior to the exterior of the building.
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Výzkum a vývoj technologie povrchových vrstev součástí valivých a kluzných ložisek / Research and Development of Technology for Surface Layers of Roll and Sliding Bearings ComponentsNěmcová, Aneta January 2008 (has links)
To increase of bearing steels properties are research and development of surface modifications well above dedicated, in present. Basic requirements to the surface modifications are high wear resistance and good temperature resistance (origin by friction). Surface modifications can not negatively influence properties of bearing steels as a substrate. One of the possibilities can be used surface modifications used for high temperature applications. These are based on saturation of substrate surface layer by Al (and Si) elements. This work deals with preparing of Al and Al-Si diffusion layers from slurries on 100Cr6 bearing steel surface and study of elements interaction between coating and bearing steel as a substrate during proceeding of protective layers at high temperatures. To elements interaction study light microscopy, scanning electron microscopy equipped by energy dispersive microanalyses, glow discharge optical emission spectrometry and microhardness measurement methods were used. To the evaluation of layer thickness image analyses was used.
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Pozorování amplitudových a fázových předmětů přes rozptylující prostředí pomocí holografického mikroskopu s kontrolovatelnou koherencí / Amplitude and phase objects observation through scattering media by means of coherence-controlled holographic microscopeEffenberger, Adam January 2015 (has links)
This diploma thesis deals with phase and amplitude objects observation through scattering media by means of a coherence-controlled holographic microscope (CCHM). A brief history of development and construction of the microscope, its advantages compared to the classical light microscopy and hologram processing are described. Quantitative phase imaging through scattering media by means of ballistic as well as diffuse light is verificated in the experimental part. A comparison of an image obtained through a scattering layer by means of CCHM and a classical microscopy in the light field is demonstrated.
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Multi-tensorové zobrazování detailu míchy z dMRI dat s vysokým úhlovým rozlišením / Multi-tensor imaging of spinal cord detail from high anglular resolution dMRI dataZimolka, Jakub January 2017 (has links)
The aim of this work was to establish a comprehensive processing pipeline of cervical spinal cord HARDI dMRI data and T2-weighted anatomical MRI images in high-resolution. In the research part we provide description of anatomical data processing, theoretical background of dMRI, description of current approaches to 3D anisotropic diffusion estimation as well as current imaging methods of spinal cord axonal bundles. As one of the first in the world, we are investigating multiple-direction diffusion models for human in-vivo spinal cord white matter minority bundles imaging. We designed our own processing pipeline utilizing Spinal Cord Toolbox (SCT), FSL, in-house developer scripts and TORQUE-based batch system for grid computation, tested on real data from cervical spinal cord area between segments C4-C6 from 26 healthy volunteers. Designed processing pipeline with one non-automatic step, works from pre-processing to parcelation of selected spinal cord structures based on co-registration with anatomical spinal cord template for 25 subjects. One person data includes motion artifacts for which the proces failed. There are visible waves in sagittal images of some subjects caused probably by blood-vessel pulsing. Local quantification metrics of spinal cord anatomy (fractional anisotropy – FA, fractional volumes of first – f1 and second – f2 direction of anisotropic diffusion) from different parts (white matter, gray matter, cortico-spinal tract) and from different population groups (men vs. women), were extracted from dMRI data. As we expected, FA maps show visible decreases in areas of gray matter. We also detected second diffusion dirrection in slices, where the spinal roots come out. In some areas, fractional volume of second diffusion direction reaches up to 40% of the total component of the dMRI signal. All mentioned parameters probability density functions for all mentioned groups are non-normal distributions. Between male and female groups there were no significant distribution differences for f1 and f2 volumes. The distribution of FA values between men and women is statistically different. Unfortunatelly, there is a significant inter-subject variability in results, which has much higher dispersion than differences between different group distributions. Despite the inter-subject variability, this work significantly extends the knowledge about data acquisiton capabilities and MRI and dMRI data from cervical spinal cord image processing. This work also lays down foundations for utilization of the imaging method in future and planned clinical research, where it will be possible to test the alteration of the spinal cord anatomy on the minor secondary bundles separately.
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Koherencí řízená holografická mikroskopie v opticky rozptylujících prostředích / COHERENCE-CONTROLLED HOLOGRAPHIC MICROSCOPY IN DIFFUSE MEDIALošťák, Martin January 2015 (has links)
This thesis deals with imaging through diffuse media in coherence-controlled holographic microscope (CCHM) developed in IPE FME BUT. The mutual coherence function as well as the signal dependence on the lateral mutual shift between both arms of the CCHM are calculated. Both functions are related to each other. The latter dependence is measured experimentally. A principle of imaging with CCHM through diffuse media with both ballistic and diffuse light is explained by a simple geometrical model. This model is then verified experimentally by imaging a sample through diffuse medium. The point spread function (PSF) of CCHM for imaging through diffuse media is then calculated. Results of PSF calculation are proved experimentally.
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