Preparation of SNOM probes with special properties

Tato bakalářská práce je zaměřena na přípravu funkčních sond z konvenčního dutého optického vlákna a jejich testování při měření na aparatuře SNOM. Dále se zde studují speciální vlastnosti těchto sond především jejich využití jako "nanoGIS". Předpokládá se vyřešení hlavních problémů spojených s přípravou sondy jako je například leptání vlákna zevnitř.This bachelor thesis is focused on preparation and testing of probes from a hollow optical fibre and their application in SNOM measurement. Further, special properties of these probes are studied, namely their use as a "nanoGIS". The main problems as etching from the inside are assumed to be solved.

Concordances in Positive Scalar Curvature and Index Theory

We apply the strategy to study of diffeomorphisms via block diffeomorphisms to the world of positive scalar curvature (psc) metrics. For each closed psc manifold $M$, we construct the cubical set $\widetilde{\mathcal{R}^{+}_{\bullet}}(M)$ of all psc block metrics, which only encodes concordance information of psc metrics within its homotopy type. We show that $\widetilde{\mathcal{R}^{+}_{\bullet}}(M)$ is a cubical Kan set, give a geometric description for the group structure of the combinatorial homotopy groups, and construct a comparison map from the cubical model $\mathcal{R}^+_{\bullet}(M)$ of the space of psc metrics on $M$ to $\widetilde{\mathcal{R}^{+}_{\bullet}}(M)$. Next, we build a concordance-themed model for real $K$-theory based on the notion of invertible block Dirac operators and use it to factor the index difference through $\widetilde{\mathcal{R}^{+}_{\bullet}}(M)$. In the final part of this thesis, we construct the psc Hatcher spectral sequence, which is a non-index-theoretic tool to get information about the difference of $\mathcal{R}^+_{\bullet}(M)$ and $\widetilde{\mathcal{R}^{+}_{\bullet}}(M)$.Comment: 259 pages, 10 figures, PhD-Thesi

Multireflector Antennas - Cascaded Structures with Frequency Selective Surfaces

The problem of increasing the gain of directional multiband antennas is solved in the paper. A single-fed multiband (wideband) planar dipole is combined with cascaded (sandwiched) reflectors made of frequency selective surfaces. Each of those reflectors is placed in a quarter-wavelength distance from the dipole at the frequency of operation. The impedance matching is particularly achieved by active element properties, and impedance symmetrization. Further transformation is made by a planar circuit, placed on the active element plane. The antenna gain is set by the reflector elements amount (reflector plane dimensions). The antenna structure enables its setting into arrays with in-phase feeding

Effective medium theory for bcc metals: Electronically non-adiabatic H atom scattering in full dimensions

In summary, we have extended the EMT formalism derived for fcc metals22 to the bcc case. We then fit the newly derived formulae to DFT data for H interacting with W and Mo, which led to full dimensional PESs and electron densities. We employed the PESs and the electron densities to carry out electronically non-adiabatic MD simulations of H atom scatter- ing, following previous work that used the LDFA approximation with a Langevin propagator. Specifically, we predict energy loss distributions for H scattering from (111) and (110) facets of these two metals at 2.76 eV incidence energy. Although no experiments are currently available for bcc metals, our results are similar to what has been seen for H scattering from fcc metals. This suggests that the current results are likely to be a reliable prediction of experiment. We find only subtle differ- ences in the energy loss distributions arising from the scatter- ing of H atom with these two metals; however, scattering from the (111) and (110) facets are distinctly different. Remarkably, on the (110) facet, we predict a clearly resolvable energy loss peak that arises from sub-surface scattering. The calculations Fig. 9 Distribution of specular scattering events as a function of the energy loss and the depth of penetration of H atom scattered from (a) Mo(110), (b) Mo(111), (c) W(110), and (d) W(111). The surface temperature is 70 K. The other conditions are the same as in Fig. 8. The signal above the black, dashed line indicate from which layer the projectiles repelled. The labels top, hcp and fcc refer to the high-symmetry sites of the (111) facet and are shown in Fig. 1(b). The bin sizes are 0.027 eV and 0.063 Å. Table 3 Sticking coefficient S0 computed from the same set of trajec- tories that were used for the calculation of the specular energy loss distributions shown in Fig. 8 System 300 K 70 K H/Mo(110) 0.44 0.44 H/Mo(111) 0.40 0.41 H/W(110) 0.42 0.41 H/W(111) 0.40 0.40 Paper PCCPOpen Access Article. Published on 04 April 2022. Downloaded on 6/8/2022 3:06:58 PM.This article is licensed under aCreative Commons Attribution 3.0 Unported Licence.View Article Online 8746 | Phys. Chem. Chem. Phys., 2022, 24, 8738–8748 This journal is © the Owner Societies 2022predict that the subsurface scattering is most easily seen for H scattering from W(110) at reduced surface temperatures

Laboratory Task - Measurement of Peristaltic Blood Pump Performance

Cílem mé práce je zhotovit laboratorní úlohu pro měření výkonu peristaltického čerpadla a navrhnout postup a měřící řetězec za pomoci desky NI ELVIS II a softwaru NI Labview. Řízení motoru pumpy obstará obvod (H – můstek) na desce NI ELVIS II a software NI Labview, které zároveň se postará o zpracování dat, které byly získány senzorem průtoku umístěným na výstupní části čerpadla.The main focus of my work is to create a laboratory task for measuring the performance of a peristaltic pump. To design a procedure and a measuring chain, using the NI ELVIS II board and NI Labview software. The engine control of the pump will provide the circuit (H – bridge) on the NI ELVIS II board and the NI Labview software, which will also take care of the processing of data obtained by the flow sensor located on the pump outlet.450 - Katedra kybernetiky a biomedicínského inženýrstvívelmi dobř

Multibounce and subsurface scattering of H atoms colliding with a van der Waals solid

We report the results of inelastic differential scattering experiments and full-dimensional molecular dynamics trajectory simulations for 2.76 eV H atoms colliding at a surface of solid xenon. The interaction potential is based on an effective medium theory (EMT) fit to density functional theory (DFT) energies. The translational energy-loss distributions derived from experiment and theory are in excellent agreement. By analyzing trajectories, we find that only a minority of the scattering results from simple single-bounce dynamics. The majority comes from multibounce collisions including subsurface scattering where the H atoms penetrate below the first layer of Xe atoms and subsequently re-emerge to the gas phase. This behavior leads to observable energy-losses as large as 0.5 eV, much larger than a prediction of the binary collision model (0.082 eV), which is often used to estimate the highest possible energy-loss in direct inelastic surface scattering. The sticking probability computed with the EMT-PES (0.15) is dramatically reduced (5 × 10–6) if we employ a full-dimensional potential energy surface (PES) based on Lennard-Jones (LJ) pairwise interactions. Although the LJ-PES accurately describes the interactions near the H–Xe and Xe–Xe energy minima, it drastically overestimates the effective size of the Xe atom seen by the colliding H atom at incidence energies above about 0.1 eV

Simulation of Viscoelastic Behavior of 3D Printed Rubber

Tato diplomová práce se zabývá nalezením vhodného konstitutivního modelu pro gumu vytištěnou na 3D tiskárně. Úvodní část práce je věnována problematice 3D tisku a přehledu dostupných technologií. Následující kapitoly jsou věnovány teoriím potřebným pro popis chování vytištěné gumy. Mezi tyto teorie patří konečné deformace, hyperelasticita a viskoelasticita. V praktické části byla nejprve provedena experimentální měření, konkrétně jednoosé tahové zkoušky a relaxační testy. Následně byl vybrán vhodný materiálový model, jedná se o kombinaci hyperelastického Yeohova modelu a viskoelastického modelu Pronyho řad. Po identifikaci materiálových parametrů modelu byly provedeny MKP simulace pro verifikaci, zda nalezený model dokáže popsat naměřené experimentální zkoušky.The aim of this diploma thesis was to find a suitable constitutive model of 3D Printed Rubber. The introduction of the thesis is dedicated to the problematics of 3D printing and 3D printing technologies overview. In the next chapters, the theories needed for the description of rubber behaviour are discussed. These theories are Finite strain theory, Hyperelasticity and Viscoelasticity. In practical part, experimental measurements were performed (uniaxial tensile tests and relaxation tests). The constitutive model was found and parameters of the model were identified based on the tests. The constitutive model consists of the hyperelastic Yeoh model and the viscoelastic Prony series. At the end of the thesis, FEM simulations were performed to verify whether the found model is able to describe the behaviour of the material during the performed tests.330 - Katedra aplikované mechanikyvýborn

Identität, Authentizität und Gemeinschaft. Warum Social Communities und Religion etwas gemeinsam haben

Soziale Netzwerke im Internet können schon seit einiger Zeit enorme Zuwächse ihrer Nutzerzahlen verbuchen. Bereits zwei Drittel aller Internetnutzer in Deutschland haben damit Erfahrungen gesammelt. Papst Benedikt ermuntert Katholiken – besonders auch Priester und junge Menschen –, die Chancen zu nutzen, die diese Medien für die Kommunikation und die Verkündigung des Evangeliums bieten. Viele religiös interessierte Internetnutzer sind bereits in Diskussionsgruppen aktiv, die sich mit religiösen Fragen beschäftigen und wünschen sich ein stärkeres Engagement der Kirche in den Sozialen Netzwerken. Die aktuelle lebhafte Diskussion über Datensicherheit in den Netzwerken zeigt die Notwendigkeit einer Vermittlung von Medienkompetenz. Dabei ist auch die Kirche als Bildungsanbieter angesprochen. Das Internet und die Sozialen Netzwerke dienen der Kommunikation in einer doppelten Weise: In der internen Kommunikation (in geschlossenen Foren und Gruppen) stärken sie den Glauben und helfen dabei, die eigene katholische Identität immer besser kennenzulernen und zu entwickeln. In der externen Kommunikation tragen sie diesen Glauben in die säkulare Welt und machen dadurch das Evangelium anderen Menschen zugänglich. Trotz aller berechtigten Kritik an den Sozialen Netzwerken sollten die Kirche und ihre Repräsentanten ihre Aktivitäten in diesem Bereich ausbauen. EnglishMichael Hertl: Identity, authenticity and community. Why Social Commu- nities and religion habe a lot in common Social Networking Services on the Internet have seen a huge rise in the number of users in recent times. In Germany already two thirds of internet users have experienced with these services. Pope Benedict encouraged Catholics – especially priests and young people – to risk enga- ging in new media for communication and proclaiming the gospel. Many users who are interested in religion are already engaged in religious discussion groups and demand a stronger involvment of the Church in Social Networking Services. The current lively discussion about security issues illustrates the need for the teaching of media literacy education, a topic that adresses the Church as provider of education. The Internet and the Social Networking Services serve communication in two ways: through internal communication (in closed forums and groups) they strengthen the faith and help individuals find and develop one‘s own catholic identity. In external communication they carry this faith into the secular world and give others access to the gospel. Despite all the justified criticism of Social Networking Services it is imperative that the Church and her agents extend their activites in this field.