National Repository of Grey Literature 41 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Robotized workplace for palletizing parts
Valenta, Jan ; Bražina, Jakub (referee) ; Vetiška, Jan (advisor)
The subject of this thesis are robotic palletizing workplaces, which are theoretically analyzed ind the research part. In practical part of this thesis, these findings are used to design a specific robotic workplace. Thereafter, this design is developed in order to acquint the reader with each part of workplace. Subsequently the workplace is digitally commissioned. The result of this thesis is fully functional CAD model of the workplace with program ready to be uploaded to the robot.
Geophysical imaging of landslides in various geological settings
Haile, Ezra Tadesse ; Valenta, Jan (advisor) ; Tábořík, Petr (referee)
A geophysical survey using the seismic refraction tomography(SRT) was carried out to study a landslide areas in Mekele, Northern Ethiopia as a part of large investigation. The study area is characterized by steep topography and a road cut of Addis Ababa-Tigray main road which has a high economic benefit for the country. In the study areas landslides are one of the most frequent geo-hazard phenomena. They are frequently damaging the road as well as the farming land, mainly during the rainy seasons. The main objective of this investigation is to produce explanatory report providing information about geotechnical properties of rocks and soils and the cause of landslides in the area. The information is utilized for planning a land use and for various kinds of engineering constructions. In addition, the obtained data and interpretation models provides information about construction material resources, identification and remediation of another geo-hazards with impact on the location, design and construction of engineering structures, and selection of potential sites for the ongoing constructions. The landslide material was characterized by a low seismic velocity. A layer of consolidated clastic rocks are considered to be the landslide bedrock and it is represented by a relatively high velocity. The...
Optical responses of biomolecules on regular metal plasmonic nanostructures
Šubr, Martin ; Procházka, Marek (advisor) ; Michl, Martin (referee) ; Valenta, Jan (referee)
Title: Optical Responses of Biomolecules on Regular Metal Plasmonic Nanostructures Author: Martin Šubr Department: Institute of Physics of Charles University Supervisor of the doctoral thesis: prof. RNDr. Marek Procházka, Dr., Institute of Physics of Charles University Abstract: Adsorption of molecules on metal plasmonic nanostructures leads to significant enhancement of many optical processes, such as Raman scattering (surface-enhanced Raman scattering - SERS) or fluorescence (surface-enhanced fluorescence - SEF). Two groups of substrates were tested within this thesis: (i) Silver nanorods prepared by oblique angle vapor deposition, and (ii) silver and gold nanoislands growing on magnetron-sputtered polytetrafluoroethylene film. Step-by- step optimization process was performed on the nanoislands in order to obtain optimum SERS sensitivity and reproducibility. Detailed SERS intensity profiles were obtained using gradient nanostructures with the localized surface plasmon resonance (LSPR) condition varying across the sample and three different excitation wavelengths. It was also found that spectral position and height of the LSPR band can be controlled simultaneously using mixed gold/silver nanoislands. Detailed investigation of polarization- and angular- dependences of anisotropic silver nanorods was...
Theory and application of optical spectroscopic methods for structural molecular studies
Hudecová, Jana ; Bouř, Petr (advisor) ; Setnička, Vladimír (referee) ; Valenta, Jan (referee)
Title: Theory and application of optical spectroscopic methods for structural molecular studies Author: RNDr. Jana Hudecová Department / Institute: Institute of Organic Chemistry and Biochemistry Supervisor of the doctoral thesis: Prof. RNDr. Petr Bouř, DSc. Abstract: In the thesis, methods of the chiroptical spectroscopy (Raman optical activity, electronic and vibrational circular dichroism, circularly polarized luminescence) were utilized to obtain information on structure of chiral molecules. In four main projects, we focused on improving accuracy of quantum-chemical computations used for interpretation of experimental spectra by including anharmonic effects, solvent, molecular flexibility and dynamics. In the first project, the normal mode geometry optimization method was investigated and a suitable frequency limit providing realistic vibrational band broadening was found. Then the ability of harmonic and anharmonic computational approaches to describe the C-H stretching vibrations was explored for three terpene molecules and four spectroscopic methods. In the third project, we estimated the role of dispersion forces and different organic solvents for conformer equilibria and dynamics of cyclic dipeptides containing tryptophan. In the last project, circularly polarized luminiscence spectra, which were...
Geophysical prospection of volcanic structures, in the area of Rybí loučky, Jizerské mountains
Fait, Václav ; Valenta, Jan (advisor) ; Skácelová, Zuzana (referee)
This thesis briefly depicts fundamental principles of three geophysical methods (gravimetry, magnetometry and electrical resistivity profiling), which had been used during research at the Rybí lou ky site in order to clarify local geological conditions. Furthermore, the reader gets acquainted with formation of a maar-diatreme, which is thought to be present at the researched site. The next part describes principles of field measurements and the procedure for evaluation of results. The results are graphically plotted in the last part. Also, the results are compared to previous investigations conducted at this site. Geophysical measurements showed that geological structures on the Rybí lou ky site are much more complex than expected. The simple diatreme structure is most likely not applicable in this case. In contrast, it is not a structure formed solely by a glacier. The origin is most likely a combination of tectonic predisposition, volcanic activity and subsequent selective erosion.
Determination of absolute quantum yield of luminescence
Smísitel, Petr ; Valenta, Jan (advisor) ; Herynková, Kateřina (referee)
In this bachelor thesis we will study the determination of absolute quantum yields (efficiency) of photoluminiscence, which is equal to the ratio of number of emitted photons and number of absorbed photons. The common approach is to compare the absorption and luminescence spectrum. The main experimental problem is to eliminate the influence of angular dependence of reflection, emission and scattering. Therefore it is convenient to use the integrating sphere which eliminate most of the problems of relative measurements of quantum yield. In detail we will describe the method to determine the quantum yields of luminescence using the integrating sphere including the description of the experimental equipment and the procedure of processing data and estimation of uncertainty. Finally, we apply the procedure to solid and liquid samples containing silicon nanocrystals. We will measure the dependence of quantum yields on the applied excitation wavelength. 1
Advanced spectroscopic characterization of quantum dot ensembles
Greben, Michael ; Valenta, Jan (advisor) ; Linnros, Jan (referee) ; Vácha, Martin (referee)
Title: Advanced spectroscopic characterization of quantum dot ensembles Author: Michael Greben Department: Department of Chemical Physics and Optics Supervisor of the doctoral thesis: Prof. Jan Valenta, Ph.D. Abstract: Semiconductor quantum dots (QDs) are small crystallites whose sizes (of the order of nm) cause spatial confinement of carriers in all 3 dimensions. As result, QDs often reveal very different physical properties in comparison with their bulk counterparts. From the optical point of view, the broadening of bandgap with QD-size shrinking is particularly interesting. It is a purely quantum mechanical effect that results from quantum confinement (QC), i.e. dimensional limitations of excitons. A strong spatial confinement leads to a relaxation of momentum (Heisenberg uncertainty principle), consequently, larger overlap of the wave-functions of carriers results in significant increase of probability of radiative recombination. Therefore ensembles of QDs are promising candidates for new generations of photonic and photovoltaic devices. This PhD thesis is primary focused on detailed spectroscopic characterization of ensembles of direct (PbS) and indirect (Si) semiconductor QDs in both colloidal (toluene) and matrix-embedded (oxide or oxinitrides multilayers) forms. The oleic- acid capped PbS QDs were...
Advanced spectroscopic characterization of quantum dot ensembles
Greben, Michael ; Valenta, Jan (advisor)
Title: Advanced spectroscopic characterization of quantum dot ensembles Author: Michael Greben Department: Department of Chemical Physics and Optics Supervisor of the doctoral thesis: Prof. Jan Valenta, Ph.D. Abstract: Semiconductor quantum dots (QDs) are small crystallites whose sizes (of the order of nm) cause spatial confinement of carriers in all 3 dimensions. As result, QDs often reveal very different physical properties in comparison with their bulk counterparts. From the optical point of view, the broadening of bandgap with QD-size shrinking is particularly interesting. It is a purely quantum mechanical effect that results from quantum confinement (QC), i.e. dimensional limitations of excitons. A strong spatial confinement leads to a relaxation of momentum (Heisenberg uncertainty principle), consequently, larger overlap of the wave-functions of carriers results in significant increase of probability of radiative recombination. Therefore ensembles of QDs are promising candidates for new generations of photonic and photovoltaic devices. This PhD thesis is primary focused on detailed spectroscopic characterization of ensembles of direct (PbS) and indirect (Si) semiconductor QDs in both colloidal (toluene) and matrix-embedded (oxide or oxinitrides multilayers) forms. The oleic- acid capped PbS QDs were...
Design of lifting beam with load capacity 15 tons.
Valenta, Jan ; Pokorný, Přemysl (referee) ; Šťastný, Antonín (advisor)
This bachelor work describes the design of the construction analysis of lifting beam simple whit fixed-distance of suspension elements. The work includes research of basic types of lifting beams, own design of the beam, solidity calculating, 3D model and drawing documentation.
New Possibilities in Fluorescence Correlation Spectroscopy
Benda, Aleš ; Hof, Martin (advisor) ; Hozák, Pavel (referee) ; Valenta, Jan (referee) ; Vácha, František (referee)
rg l sit lillltili al s i1ttl11tigl a uD ... EEJ Ěts ; i išl it gilBg*E Ě i: : .liiEt t liiiiH aŮ i ĚÉ;Eg gšgiiíilgaggi$Ěgi$Éiiiť6!= gggii;gggpiiigiífugii!.ilii;i iglgi iĚiigíiiliiiil F giii it gi ii Ě{iiÉÉ{ĚĚÉEá}iIEEE;gEÉEEÉi Igig;i';;;i *'i'*ĚiiE ; E'iEĚš gEEEĚB] ggg;gálsgggltĚaa*aĚ:áisil! titlltgiitgillrĚllĚgE'! iEeIĚEEiEEE: glii ttgit11tglá1,š šl ilti1laig : x o o. G o- x o CL (o o- o o (u .9 CL CL q a) ts 3 9.= P ;i!!= řpEšE'- ža:- ':9YE,E TEPšij=;^yo 9EBV-' H g ya I eĚĚ99Ě=Éo o Ě.q9€y EEŽsp r'tr.=k e5;S* ?a.E9'YE,XŤóxqĚrl - .= t O L,-GUT :E!.i.o óěEx= .^5ě(n6 oEEt+4 €E€ýp= B:ž:řb Hšťo;^F"č'= 9;ŤĚE:*řoo EiSšJbDY ěřxF 9,E fr -'3 gEg ĚĚěiE ĚigE -,, --"a; Ě??E=: ič99 C) Ep,E Ě.E!E.P EE2'E E ĚřiEÉEEiEeEĚŤE i g€EEřEÉaEř Eitěi a EE;É€lĚEEĚ EĚBóa : t:gi;Ť!Eá**i.;E€ř.gÉE É"E Ť.g g ř tí€ tc E #-! E $ .} i ;t íe];a= E E ÉěE E : t E,,! 2 EÉÉEÉĚĚEiEEĚEĚEěEia g:ei!:€EÉĚtEEEEE#ii i!= H g"a" *is; :F- ; gÉE3 Eé = o a o o o d hD o € bo E o l-.. JO ,o i>ro 1 ójt )é) 4O Na tu-E- ýc ž.( oo) o;o' o' € F. 6 o G0 o r o o ,o lÉ I^ )o JQ !ř € 9 E E E ?: E '$E,3; E EB: Eei€Ř iEi e*ĚE-: Ée EF.9 už ÉE E;E;E E,g tE;iÉ ;Ě fi Ě i š; ? t t Ě€Eř g ó o.a E á! t e E E :5i.q6':É9= EEE:EagEĚ igEHÉEEE! ĚgEiĚtÉě.'z éz; E ě i = t E a E ; ae:: € E o bo oo aEEiEÉEiEigEEEiiEÉi EEÍeĚE*EIĚIěiiI:EEi EŤ€ĚiÉi!EE{E€EE5;tĚ aiEĚt?€iiŤÉÉEEitÍzÉ...

National Repository of Grey Literature : 41 records found   1 - 10nextend  jump to record:
See also: similar author names
6 Valenta, Jakub
14 Valenta, Jaroslav
5 Valenta, Jiří
3 Valenta, Josef
Interested in being notified about new results for this query?
Subscribe to the RSS feed.