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In this thesis, the surface properties of cassiterite due to the changes of two material properties, i.e. crystallographic orientation, and Fe as a minor element in the lattice, and their implication for selective separation are studied. In the study of the crystallographic orientation of cassiterite, the physicochemical behaviors of the surfaces SnO2(110), SnO2(100), as well as SnO2(001) were investigated by using high-resolution direct force spectroscopy. The measurements were conducted between a silica sphere and sample surfaces in 10 mmol/L KCl between pH 3.1 and 6.2 using colloidal probe atomic force microscopy (cp-AFM-hydrophilic). Dissimilar interactions were detected on different-oriented surfaces. The pH values where the force switched from positive to negative can be clearly distinguished and be ordered as SnO2(100) < SnO2(001) ≈ SnO2(110). The most potent attractive force was found to be on the (110) cassiterite surface compared to the (100) and (001) cassiterite surfaces at lower pH. By fitting the force curves in the DLVO theory framework, anisotropic surface potentials were computed between the three sample surfaces following a similar trend as force interaction. This differential surface potential might be due to the difference in Sn cation density and electron affinity. To study the implication of crystallographic orientation to surfactant adsorption, we used Aerosol22 (sulfosuccinamate) as an anionic collector for cassiterite flotation to functionalize the different samples at pH 3. The contact angle measurements, the topography visualizations by AFM, and the force measurement using cp-AFM with hydrophobized spheres (cp-AFM-hydrophobized) have shown that Aerosol22 was adsorbed on the sample surfaces inhomogeneously. The adsorption followed the order of SnO2(110) > SnO2(100) > SnO2(001) in the concentration from 1 × 10−6 mol/L to 1 × 10−4 mol/L. In the study of Fe as a minor element in the lattice of cassiterite, synthetic pure cassiterite, and cassi

The first Sino-German workshop on “Deep-sea mining of massive sulfides: balancing impacts on biodiversity and ecosystem, technological challenges and law of the sea” took place from September 17 to September 23, 2023 in Changsha, Hunan Province, China. Four themes were covered by 20 impulse talks, (1) seabed resources and mineralization systems, marine geology and geochemistry, (2) microbiology and marine ecology, (3) deep-sea mining technology, mineral processing and extractive metallurgy, and (4) law of the sea and international law applicable to the marine environment in Areas Beyond National Jurisdiction, respectively. In round table discussions, the interdisciplinary understanding deepened regarding (i) the distribution of submarine massive sulfides (SMS), their formation mechanisms and the abundance of SMS resources, (ii) the biodiversity linked to SMS and hydrothermal vents and the environmental protection requirements, (iii) the challenges of mining technology and processing of SMS, as well as (iv) the legal framework, the regulatory challenges, the international environmental liability regime and due diligence obligations for commercial seabed mining. The participants covered all four themes and are affiliated with various universities, research institutions, and governmental geoscientific authorities from China (seven) and Germany (six). During the workshop, a number of recommendations to ISA were defined regarding environmental, methodological, technical, and legal issues.

The first Sino-German workshop on “Deep-sea mining of massive sulfides: balancing impacts on biodiversity and ecosystem, technological challenges and law of the sea” took place from September 17 to September 23, 2023 in Changsha, Hunan Province, China. Four themes were covered by 20 impulse talks, (1) seabed resources and mineralization systems, marine geology and geochemistry, (2) microbiology and marine ecology, (3) deep-sea mining technology, mineral processing and extractive metallurgy, and (4) law of the sea and international law applicable to the marine environment in Areas Beyond National Jurisdiction, respectively. In round table discussions, the interdisciplinary understanding deepened regarding (i) the distribution of submarine massive sulfides (SMS), their formation mechanisms and the abundance of SMS resources, (ii) the biodiversity linked to SMS and hydrothermal vents and the environmental protection requirements, (iii) the challenges of mining technology and processing of SMS, as well as (iv) the legal framework, the regulatory challenges, the international environmental liability regime and due diligence obligations for commercial seabed mining. The participants covered all four themes and are affiliated with various universities, research institutions, and governmental geoscientific authorities from China (seven) and Germany (six). During the workshop, a number of recommendations to ISA were defined regarding environmental, methodological, technical, and legal issues.

High power impulse magnetron sputtering (HiPIMS) discharges with a zirconium target are studied experimentally and by applying the ionization region model (IRM). The measured ionized flux fraction lies in the range between 25% and 59% and increases with increased peak discharge current density ranging from 0.5 to 2 A/cm(2) at a working gas pressure of 1 Pa. At the same time, the sputter rate-normalized deposition rate determined by the IRM decreases in accordance with the HiPIMS compromise. For a given discharge current and voltage waveform, using the measured ionized flux fraction to lock the model, the IRM provides the temporal variation of the various species and the average electron energy within the ionization region, as well as internal discharge parameters such as the ionization probability and the back-attraction probability of the sputtered species. The ionization probability is found to be in the range 73%-91%, and the back-attraction probability is in the range 67%-77%. Significant working gas rarefaction is observed in these discharges. The degree of working gas rarefaction is in the range 45%-85%, higher for low pressure and higher peak discharge current density. We find electron impact ionization to be the main contributor to working gas rarefaction, with over 80% contribution, while kick-out by zirconium atoms and argon atoms from the target has a smaller contribution. The dominating contribution of electron impact ionization to working gas rarefaction is very similar to other low sputter yield materials., QC 20240828

The ionization region model (IRM) is applied to explore working gas rarefaction in high power impulse magnetron sputtering discharges operated with graphite, aluminum, copper, titanium, zirconium, and tungsten targets. For all cases the working gas rarefaction is found to be significant, the degree of working gas rarefaction reaches values of up to 83%. The various contributions to working gas rarefaction, including electron impact ionization, kick-out by the sputtered species or hot argon atoms, and diffusion, are evaluated and compared for the different target materials, and over a range of discharge current densities. The relative importance of the various processes varies between different target materials. In the case of a graphite target with argon as the working gas at 1 Pa, electron impact ionization (by both primary and secondary electrons) is the dominating contributor to working gas rarefaction, with over 90% contribution, while the contribution of sputter wind kick-out is small < 10 %. In the case of copper and tungsten targets, the kick-out dominates, with up to ∼60% contribution at 1 Pa. For metallic targets the kick-out is mainly due to metal atoms sputtered from the target, while for the graphite target the small kick-out contribution is mainly due to kick-out by hot argon atoms and to a smaller extent by carbon atoms. The main factors determining the relative contribution of the kick-out by the sputtered species to working gas rarefaction appear to be the sputter yield and the working gas pressure., QC 20240627

In this thesis, the surface properties of cassiterite due to the changes of two material properties, i.e. crystallographic orientation, and Fe as a minor element in the lattice, and their implication for selective separation are studied. In the study of the crystallographic orientation of cassiterite, the physicochemical behaviors of the surfaces SnO2(110), SnO2(100), as well as SnO2(001) were investigated by using high-resolution direct force spectroscopy. The measurements were conducted between a silica sphere and sample surfaces in 10 mmol/L KCl between pH 3.1 and 6.2 using colloidal probe atomic force microscopy (cp-AFM-hydrophilic). Dissimilar interactions were detected on different-oriented surfaces. The pH values where the force switched from positive to negative can be clearly distinguished and be ordered as SnO2(100) < SnO2(001) ≈ SnO2(110). The most potent attractive force was found to be on the (110) cassiterite surface compared to the (100) and (001) cassiterite surfaces at lower pH. By fitting the force curves in the DLVO theory framework, anisotropic surface potentials were computed between the three sample surfaces following a similar trend as force interaction. This differential surface potential might be due to the difference in Sn cation density and electron affinity. To study the implication of crystallographic orientation to surfactant adsorption, we used Aerosol22 (sulfosuccinamate) as an anionic collector for cassiterite flotation to functionalize the different samples at pH 3. The contact angle measurements, the topography visualizations by AFM, and the force measurement using cp-AFM with hydrophobized spheres (cp-AFM-hydrophobized) have shown that Aerosol22 was adsorbed on the sample surfaces inhomogeneously. The adsorption followed the order of SnO2(110) > SnO2(100) > SnO2(001) in the concentration from 1 × 10−6 mol/L to 1 × 10−4 mol/L. In the study of Fe as a minor element in the lattice of cassiterite, synthetic pure cassiterite, and cassi

Here, we compare the ionization region model (IRM) against experimental measurements of particle densities and electron temperature in a high power impulse magnetron sputtering discharge with a tungsten target. The semi-empirical model provides volume-averaged temporal variations of the various species densities as well as the electron energy for a particular cathode target material, when given the measured discharge current and voltage waveforms. The model results are compared to the temporal evolution of the electron density and the electron temperature determined by Thomson scattering measurements and the temporal evolution of the relative neutral and ion densities determined by optical emission spectrometry. While the model underestimates the electron density and overestimates the electron temperature, the temporal trends of the species densities and the electron temperature are well captured by the IRM., Funding Agencies|Icelandic Research Fund [196141]; Swedish Research Council [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

Here, we compare the ionization region model (IRM) against experimental measurements of particle densities and electron temperature in a high power impulse magnetron sputtering discharge with a tungsten target. The semi-empirical model provides volume-averaged temporal variations of the various species densities as well as the electron energy for a particular cathode target material, when given the measured discharge current and voltage waveforms. The model results are compared to the temporal evolution of the electron density and the electron temperature determined by Thomson scattering measurements and the temporal evolution of the relative neutral and ion densities determined by optical emission spectrometry. While the model underestimates the electron density and overestimates the electron temperature, the temporal trends of the species densities and the electron temperature are well captured by the IRM., Funding Agencies|Icelandic Research Fund [196141]; Swedish Research Council [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

Here, we compare the ionization region model (IRM) against experimental measurements of particle densities and electron temperature in a high power impulse magnetron sputtering discharge with a tungsten target. The semi-empirical model provides volume-averaged temporal variations of the various species densities as well as the electron energy for a particular cathode target material, when given the measured discharge current and voltage waveforms. The model results are compared to the temporal evolution of the electron density and the electron temperature determined by Thomson scattering measurements and the temporal evolution of the relative neutral and ion densities determined by optical emission spectrometry. While the model underestimates the electron density and overestimates the electron temperature, the temporal trends of the species densities and the electron temperature are well captured by the IRM., QC 20230412

Here, we compare the ionization region model (IRM) against experimental measurements of particle densities and electron temperature in a high power impulse magnetron sputtering discharge with a tungsten target. The semi-empirical model provides volume-averaged temporal variations of the various species densities as well as the electron energy for a particular cathode target material, when given the measured discharge current and voltage waveforms. The model results are compared to the temporal evolution of the electron density and the electron temperature determined by Thomson scattering measurements and the temporal evolution of the relative neutral and ion densities determined by optical emission spectrometry. While the model underestimates the electron density and overestimates the electron temperature, the temporal trends of the species densities and the electron temperature are well captured by the IRM., Funding Agencies|Icelandic Research Fund [196141]; Swedish Research Council [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

Here, we compare the ionization region model (IRM) against experimental measurements of particle densities and electron temperature in a high power impulse magnetron sputtering discharge with a tungsten target. The semi-empirical model provides volume-averaged temporal variations of the various species densities as well as the electron energy for a particular cathode target material, when given the measured discharge current and voltage waveforms. The model results are compared to the temporal evolution of the electron density and the electron temperature determined by Thomson scattering measurements and the temporal evolution of the relative neutral and ion densities determined by optical emission spectrometry. While the model underestimates the electron density and overestimates the electron temperature, the temporal trends of the species densities and the electron temperature are well captured by the IRM., Funding Agencies|Icelandic Research Fund [196141]; Swedish Research Council [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

Here, we compare the ionization region model (IRM) against experimental measurements of particle densities and electron temperature in a high power impulse magnetron sputtering discharge with a tungsten target. The semi-empirical model provides volume-averaged temporal variations of the various species densities as well as the electron energy for a particular cathode target material, when given the measured discharge current and voltage waveforms. The model results are compared to the temporal evolution of the electron density and the electron temperature determined by Thomson scattering measurements and the temporal evolution of the relative neutral and ion densities determined by optical emission spectrometry. While the model underestimates the electron density and overestimates the electron temperature, the temporal trends of the species densities and the electron temperature are well captured by the IRM., Funding Agencies|Icelandic Research Fund [196141]; Swedish Research Council [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

The ionization region model (IRM) is applied to model a high power impulse magnetron sputtering discharge with a tungsten target. The IRM gives the temporal variation of the various species and the average electron energy, as well as internal discharge parameters such as the ionization probability and the back-attraction probability of the sputtered species. It is shown that an initial peak in the discharge current is due to argon ions bombarding the cathode target. After the initial peak, the W+ ions become the dominating ions and remain as such to the end of the pulse. We demonstrate how the contribution of the W+ ions to the total discharge current at the target surface increases with increased discharge voltage for peak discharge current densities J (D,peak) in the range 0.33-0.73 A cm(-2). For the sputtered tungsten the ionization probability increases, while the back-attraction probability decreases with increasing discharge voltage. Furthermore, we discuss the findings in terms of the generalized recycling model and compare to experimentally determined deposition rates and find good agreement., Funding Agencies|Icelandic Research Fund [196141]; Free State of Saxony; European Regional Development Fund [100336119]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

The ionization region model (IRM) is applied to model a high power impulse magnetron sputtering discharge with a tungsten target. The IRM gives the temporal variation of the various species and the average electron energy, as well as internal discharge parameters such as the ionization probability and the back-attraction probability of the sputtered species. It is shown that an initial peak in the discharge current is due to argon ions bombarding the cathode target. After the initial peak, the W+ ions become the dominating ions and remain as such to the end of the pulse. We demonstrate how the contribution of the W+ ions to the total discharge current at the target surface increases with increased discharge voltage for peak discharge current densities J (D,peak) in the range 0.33-0.73 A cm(-2). For the sputtered tungsten the ionization probability increases, while the back-attraction probability decreases with increasing discharge voltage. Furthermore, we discuss the findings in terms of the generalized recycling model and compare to experimentally determined deposition rates and find good agreement., Funding Agencies|Icelandic Research Fund [196141]; Free State of Saxony; European Regional Development Fund [100336119]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

The ionization region model (IRM) is applied to model a high power impulse magnetron sputtering discharge with a tungsten target. The IRM gives the temporal variation of the various species and the average electron energy, as well as internal discharge parameters such as the ionization probability and the back-attraction probability of the sputtered species. It is shown that an initial peak in the discharge current is due to argon ions bombarding the cathode target. After the initial peak, the W+ ions become the dominating ions and remain as such to the end of the pulse. We demonstrate how the contribution of the W+ ions to the total discharge current at the target surface increases with increased discharge voltage for peak discharge current densities J (D,peak) in the range 0.33-0.73 A cm(-2). For the sputtered tungsten the ionization probability increases, while the back-attraction probability decreases with increasing discharge voltage. Furthermore, we discuss the findings in terms of the generalized recycling model and compare to experimentally determined deposition rates and find good agreement., QC 20230404

The ionization region model (IRM) is applied to model a high power impulse magnetron sputtering discharge with a tungsten target. The IRM gives the temporal variation of the various species and the average electron energy, as well as internal discharge parameters such as the ionization probability and the back-attraction probability of the sputtered species. It is shown that an initial peak in the discharge current is due to argon ions bombarding the cathode target. After the initial peak, the W+ ions become the dominating ions and remain as such to the end of the pulse. We demonstrate how the contribution of the W+ ions to the total discharge current at the target surface increases with increased discharge voltage for peak discharge current densities J (D,peak) in the range 0.33-0.73 A cm(-2). For the sputtered tungsten the ionization probability increases, while the back-attraction probability decreases with increasing discharge voltage. Furthermore, we discuss the findings in terms of the generalized recycling model and compare to experimentally determined deposition rates and find good agreement., Funding Agencies|Icelandic Research Fund [196141]; Free State of Saxony; European Regional Development Fund [100336119]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

In this paper, we present a novel method for integrating 3D LiDAR depth measurements into the existing ORB-SLAM3 by building upon the RGB-D mode. We propose and compare two methods of depth map generation: conventional computer vision methods, namely an inverse dilation operation, and a supervised deep learning-based approach. We integrate the former directly into the ORB-SLAM3 framework by adding a so-called RGB-L (LiDAR) mode that directly reads LiDAR point clouds. The proposed methods are evaluated on the KITTI Odometry dataset and compared to each other and the standard ORB-SLAM3 stereo method. We demonstrate that, depending on the environment, advantages in trajectory accuracy and robustness can be achieved. Furthermore, we demonstrate that the runtime of the ORB-SLAM3 algorithm can be reduced by more than 40 % compared to the stereo mode. The related code for the ORB-SLAM3 RGB-L mode will be available as open-source software under https://github.com/TUMFTM/ORB SLAM3 RGBL., Comment: Accepted at ICCCR 2023

The ionization region model (IRM) is applied to model a high power impulse magnetron sputtering discharge with a tungsten target. The IRM gives the temporal variation of the various species and the average electron energy, as well as internal discharge parameters such as the ionization probability and the back-attraction probability of the sputtered species. It is shown that an initial peak in the discharge current is due to argon ions bombarding the cathode target. After the initial peak, the W+ ions become the dominating ions and remain as such to the end of the pulse. We demonstrate how the contribution of the W+ ions to the total discharge current at the target surface increases with increased discharge voltage for peak discharge current densities J (D,peak) in the range 0.33-0.73 A cm(-2). For the sputtered tungsten the ionization probability increases, while the back-attraction probability decreases with increasing discharge voltage. Furthermore, we discuss the findings in terms of the generalized recycling model and compare to experimentally determined deposition rates and find good agreement., Funding Agencies|Icelandic Research Fund [196141]; Free State of Saxony; European Regional Development Fund [100336119]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

The ionization region model (IRM) is applied to model a high power impulse magnetron sputtering discharge with a tungsten target. The IRM gives the temporal variation of the various species and the average electron energy, as well as internal discharge parameters such as the ionization probability and the back-attraction probability of the sputtered species. It is shown that an initial peak in the discharge current is due to argon ions bombarding the cathode target. After the initial peak, the W+ ions become the dominating ions and remain as such to the end of the pulse. We demonstrate how the contribution of the W+ ions to the total discharge current at the target surface increases with increased discharge voltage for peak discharge current densities J (D,peak) in the range 0.33-0.73 A cm(-2). For the sputtered tungsten the ionization probability increases, while the back-attraction probability decreases with increasing discharge voltage. Furthermore, we discuss the findings in terms of the generalized recycling model and compare to experimentally determined deposition rates and find good agreement., Funding Agencies|Icelandic Research Fund [196141]; Free State of Saxony; European Regional Development Fund [100336119]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

We apply the ionization region model (IRM) and the Orsay Boltzmann equation for electrons coupled with ionization and excited states kinetics (OBELIX) model to study the electron kinetics of a high power impulse magnetron sputtering (HiPIMS) discharge. In the IRM the bulk (cold) electrons are assumed to exhibit a Maxwellian energy distribution and the secondary (hot) electrons, emitted from the target surface upon ion bombardment, are treated as a high energy tail, while in the OBELIX the electron energy distribution is calculated self-consistently using an isotropic Boltzmann equation. The two models are merged in the sense that the output from the IRM is used as an input for OBELIX. The temporal evolutions of the particle densities are found to agree very well between the two models. Furthermore, a very good agreement is demonstrated between the bi-Maxwellian electron energy distribution assumed by the IRM and the electron energy distribution calculated by the OBELIX model. It can therefore be concluded that assuming a bi-Maxwellian electron energy distribution, constituting a cold bulk electron group and a hot secondary electron group, is a good approximation for modeling the HiPIMS discharge., QC 20210601

The possibility to optimize a high-power impulse magnetron sputtering (HiPIMS) discharge through mixing two different power levels in the pulse pattern is investigated. Standard HiPIMS pulses are used to create the ions of the film-forming material. After each HiPIMS pulse an off-time follows, during which no voltage (or, optionally, a reversed voltage) is applied, letting the remaining ions in the magnetic trap escape towards the substrate. After these off-times, a long second pulse with lower amplitude, in the dc magnetron sputtering range, is applied. During this pulse, which is continued up to the following HiPIMS pulse, mainly neutrals of the film-forming material are produced. This pulse pattern makes it possible to achieve separate optimization of the ion production, and of the neutral atom production, that constitute the film-forming flux to the substrate. The optimization process is thereby separated into two sub-problems. The first sub-problem concerns minimizing the energy cost for ion production, and the second sub-problem deals with how to best split a given allowed discharge power between ion production and neutral production. The optimum power split is decided by the lowest ionized flux fraction that gives the desired film properties for a specific application. For the first sub-problem we describe a method where optimization is achieved by the selection of five process parameters: the HiPIMS pulse amplitude, the HiPIMS pulse length, the off-time, the working gas pressure, and the magnetic field strength. For the second sub-problem, the splitting of power between ion and neutral production, optimization is achieved by the selection of the values of two remaining process parameters, the HiPIMS pulse repetition frequency and the discharge voltage of the low-power pulse., QC 20210301

High-power impulse magnetron sputtering (HiPIMS) is an ionized physical vapor deposition technique that provides a high flux of ionized target species for thin film growth. Optimization of HiPIMS processes is, however, often difficult, since the influence of external process parameters, such as working gas pressure, magnetic field strength, and pulse configuration, on the deposition process characteristics is not well understood. The reason is that these external parameters are only indirectly connected to the two key flux parameters, the deposition rate and ionized flux fraction, via two internal discharge parameters: the target atom ionization probability alpha (t) and the target ion back-attraction probability beta (t). Until now, it has been difficult to assess alpha (t) and beta (t) without resorting to computational modeling, which has hampered knowledge-based optimization. Here, we present a simple method to deduce alpha (t) and beta (t) based on measured deposition rates of neutrals and ions. The core of the method is a refined analytical model, which is described in detail. This approach is furthermore validated by independent calculations of alpha (t) and beta (t) using the considerably more complex ionization region model, which is a plasma-chemical global discharge model., QC 20210211

We apply the ionization region model (IRM) and the Orsay Boltzmann equation for electrons coupled with ionization and excited states kinetics (OBELIX) model to study the electron kinetics of a high power impulse magnetron sputtering (HiPIMS) discharge. In the IRM the bulk (cold) electrons are assumed to exhibit a Maxwellian energy distribution and the secondary (hot) electrons, emitted from the target surface upon ion bombardment, are treated as a high energy tail, while in the OBELIX the electron energy distribution is calculated self-consistently using an isotropic Boltzmann equation. The two models are merged in the sense that the output from the IRM is used as an input for OBELIX. The temporal evolutions of the particle densities are found to agree very well between the two models. Furthermore, a very good agreement is demonstrated between the bi-Maxwellian electron energy distribution assumed by the IRM and the electron energy distribution calculated by the OBELIX model. It can therefore be concluded that assuming a bi-Maxwellian electron energy distribution, constituting a cold bulk electron group and a hot secondary electron group, is a good approximation for modeling the HiPIMS discharge., Funding Agencies|Free State of Saxony; European Regional Development FundEuropean Commission [100336119]; Icelandic Research Fund [130029, 196141]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [VR 201804139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]

The possibility to optimize a high-power impulse magnetron sputtering (HiPIMS) discharge through mixing two different power levels in the pulse pattern is investigated. Standard HiPIMS pulses are used to create the ions of the film-forming material. After each HiPIMS pulse an off-time follows, during which no voltage (or, optionally, a reversed voltage) is applied, letting the remaining ions in the magnetic trap escape towards the substrate. After these off-times, a long second pulse with lower amplitude, in the dc magnetron sputtering range, is applied. During this pulse, which is continued up to the following HiPIMS pulse, mainly neutrals of the film-forming material are produced. This pulse pattern makes it possible to achieve separate optimization of the ion production, and of the neutral atom production, that constitute the film-forming flux to the substrate. The optimization process is thereby separated into two sub-problems. The first sub-problem concerns minimizing the energy cost for ion production, and the second sub-problem deals with how to best split a given allowed discharge power between ion production and neutral production. The optimum power split is decided by the lowest ionized flux fraction that gives the desired film properties for a specific application. For the first sub-problem we describe a method where optimization is achieved by the selection of five process parameters: the HiPIMS pulse amplitude, the HiPIMS pulse length, the off-time, the working gas pressure, and the magnetic field strength. For the second sub-problem, the splitting of power between ion and neutral production, optimization is achieved by the selection of the values of two remaining process parameters, the HiPIMS pulse repetition frequency and the discharge voltage of the low-power pulse., Funding Agencies|Icelandic Research Fund [196141]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Free State of Saxony; European Regional Development FundEuropean Commission [100336119]; Svensk-Franska Stiftelsen

High-power impulse magnetron sputtering (HiPIMS) is an ionized physical vapor deposition technique that provides a high flux of ionized target species for thin film growth. Optimization of HiPIMS processes is, however, often difficult, since the influence of external process parameters, such as working gas pressure, magnetic field strength, and pulse configuration, on the deposition process characteristics is not well understood. The reason is that these external parameters are only indirectly connected to the two key flux parameters, the deposition rate and ionized flux fraction, via two internal discharge parameters: the target atom ionization probability alpha (t) and the target ion back-attraction probability beta (t). Until now, it has been difficult to assess alpha (t) and beta (t) without resorting to computational modeling, which has hampered knowledge-based optimization. Here, we present a simple method to deduce alpha (t) and beta (t) based on measured deposition rates of neutrals and ions. The core of the method is a refined analytical model, which is described in detail. This approach is furthermore validated by independent calculations of alpha (t) and beta (t) using the considerably more complex ionization region model, which is a plasma-chemical global discharge model., Funding Agencies|Free State of Saxony; European Regional Development FundEuropean Union (EU) [100336119]; Icelandic Research Fund [130029, 196141]; Swedish Research CouncilSwedish Research Council [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]

In high power impulse magnetron sputtering (HiPIMS) operation, there are basically two goals: a high ionized flux fraction of the sputtered target material and a high deposition rate. In this work, it is demonstrated that the former always comes at the cost of the latter. This makes a choice necessary, referred to as the HiPIMS compromise. It is here proposed that this compromise is most easily made by varying the discharge current amplitude, which opens up for optimization of additionally four external process parameters: the pulse length, the working gas pressure, the magnetic field strength, and the degree of magnetic unbalance to achieve the optimum combination of the ionized flux fraction and the deposition rate. As a figure of merit, useful for comparing different discharges, ( 1 - beta t ) is identified, which is the fraction of ionized sputtered material that escapes back-attraction toward the cathode target. It is shown that a discharge with a higher value of ( 1 - beta t ) always can be arranged to give better combinations of ionization and deposition rate than a discharge with a lower ( 1 - beta t ). Maximization of ( 1 - beta t ) is carried out empirically, based on data from two discharges with Ti targets in Ar working gas. These discharges were first modeled in order to convert measured plasma parameters to values of ( 1 - beta t ). The combined effects of varying the different process parameters were then analyzed using a process flow chart model. The effect of varying the degree of unbalance in the studied range was small. For the remaining three parameters, it is found that optimum is achieved by minimizing the magnetic field strength, minimizing the working gas pressure, and minimizing the pulse length as far as compatible with the requirement to ignite and maintain a stable discharge., QC 20200525

High power impulse magnetron sputtering (HiPIMS) is an ionized physical vapour deposition technique. While HiPIMS provides a high flux of metal ions to the substrate, the disadvantage is a reduced deposition rate compared to direct current magnetron sputtering (dcMS) at equal average power. This is mainly due to the high target back-attraction probability of the metal ions with typical values in the range 70%-90% during the pulse. In this work, we investigate how to reduce this effect by quantifying the contribution of the metal ion flux after each HiPIMS pulse, a period also known as afterglow. Without a negative potential on the target at this stage of the HiPIMS process, the back-attracting electric field disappears allowing remaining ions to escape the ionization region. In order to analyze the fate of the film-forming ions, we extend the time-dependent ionization region model (IRM) by adding consideration of an afterglow. This approach allows to distinguish between fluxes from the ionization region during the pulse and during the afterglow. We show that by shortening the pulse length of a titanium HiPIMS discharge, the contribution to the outward flux of film-forming species from the afterglow increases significantly. The IRM predicts a gain in deposition rate of 46% and 47% for two discharges with different peak discharge currents, when using 40 mu s compared to 100 mu s-long pulses at the same average power. This is without compromising the ionized flux fraction that remains constant for the range of pulse lengths investigated here., QC 20200608

High power impulse magnetron sputtering (HiPIMS) is an ionized physical vapour deposition technique. While HiPIMS provides a high flux of metal ions to the substrate, the disadvantage is a reduced deposition rate compared to direct current magnetron sputtering (dcMS) at equal average power. This is mainly due to the high target back-attraction probability of the metal ions with typical values in the range 70%-90% during the pulse. In this work, we investigate how to reduce this effect by quantifying the contribution of the metal ion flux after each HiPIMS pulse, a period also known as afterglow. Without a negative potential on the target at this stage of the HiPIMS process, the back-attracting electric field disappears allowing remaining ions to escape the ionization region. In order to analyze the fate of the film-forming ions, we extend the time-dependent ionization region model (IRM) by adding consideration of an afterglow. This approach allows to distinguish between fluxes from the ionization region during the pulse and during the afterglow. We show that by shortening the pulse length of a titanium HiPIMS discharge, the contribution to the outward flux of film-forming species from the afterglow increases significantly. The IRM predicts a gain in deposition rate of 46% and 47% for two discharges with different peak discharge currents, when using 40 mu s compared to 100 mu s-long pulses at the same average power. This is without compromising the ionized flux fraction that remains constant for the range of pulse lengths investigated here., Funding Agencies|Free State of Saxony [100336119]; European Regional Development FundEuropean Union (EU) [100336119]; University of Iceland Research Fund for Doctoral students; Icelandic Research Fund [196141]; Swedish Research CouncilSwedish Research Council [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]

In high power impulse magnetron sputtering (HiPIMS) operation, there are basically two goals: a high ionized flux fraction of the sputtered target material and a high deposition rate. In this work, it is demonstrated that the former always comes at the cost of the latter. This makes a choice necessary, referred to as the HiPIMS compromise. It is here proposed that this compromise is most easily made by varying the discharge current amplitude, which opens up for optimization of additionally four external process parameters: the pulse length, the working gas pressure, the magnetic field strength, and the degree of magnetic unbalance to achieve the optimum combination of the ionized flux fraction and the deposition rate. As a figure of merit, useful for comparing different discharges, ( 1 - beta t ) is identified, which is the fraction of ionized sputtered material that escapes back-attraction toward the cathode target. It is shown that a discharge with a higher value of ( 1 - beta t ) always can be arranged to give better combinations of ionization and deposition rate than a discharge with a lower ( 1 - beta t ). Maximization of ( 1 - beta t ) is carried out empirically, based on data from two discharges with Ti targets in Ar working gas. These discharges were first modeled in order to convert measured plasma parameters to values of ( 1 - beta t ). The combined effects of varying the different process parameters were then analyzed using a process flow chart model. The effect of varying the degree of unbalance in the studied range was small. For the remaining three parameters, it is found that optimum is achieved by minimizing the magnetic field strength, minimizing the working gas pressure, and minimizing the pulse length as far as compatible with the requirement to ignite and maintain a stable discharge., Funding Agencies|Svensk-Franska Stiftelsen; Icelandic Research Fund [130029, 196141]; Swedish Research CouncilSwedish Research Council [VR 2018-04139]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Free State of Saxony [100336119]; European Regional Development FundEuropean Union (EU) [100336119]

In der sozialpädagogischen Arbeit können Situationen entstehen, in denen Fachkräften vertrauliche Informationen zuteil werden, deren Schutz im Eigeninteresse der Adressat*innen oder des Staates liegen kann. Insbesondere die niedrigschwellige Arbeit mit Personen und Gruppen, die aus verschiedenen Gründen eine skeptische bis ablehnende Haltung gegenüber institutionellen Strukturen einnehmen – also mitunter auch Einrichtungen, für die Sozialarbeiter*innen tätig sind – oder mit Menschen, die beispielsweise aufgrund stoffgebundener Abhängigkeiten oder Verwicklungen in als extremistisch definierten Gruppen Strafverfolgung befürchten, erfordert von Sozialarbeiter*innen ein hohes Maß an Sensibilität für die eigene Rolle als Geheimnisträger nach § 203 Strafgesetzbuch (StGB). Gleiches gilt für Hilfesuchende, die sich an Opferberatungsstellen wenden und womöglich aus persönlichen Gründen ein Strafverfahren ablehnen, auch wenn sie selbst nicht beschuldigt wären. Die im Vertrauen von Adressat*innen erlangte Erkenntnis unterliegt zwar der Schweigepflicht, dies sichert den Sozialarbeiter*innen mit staatlicher Anerkennung im Strafverfahren allerdings kein Zeugnisverweigerungsrecht nach § 53 Strafprozessordnung (StPO) zu. Beides sind unterschiedliche rechtliche Regelungen, allerdings gibt es mit Ärzt*innen, Rechtsanwält*innen, Psycholog*innen, Journalist*innen, etc. Berufsgruppen, die in beiden Gesetzestexten berücksichtigt werden. Für Sozialarbeiter*innen gilt dieser Umstand nicht, ein Zeugnisverweigerungsrecht steht ihnen im Strafverfahren, mit Ausnahme von entsprechend qualifizierten Mitarbeiter*innen in Schwangerschaftsberatungsstellen sowie Beratungsstellen für Betäubungsmittelabhängige, nicht zu. Die vorliegende Masterarbeit beleuchtet die rechtliche und fachliche Aspekte des fehlenden Zeugnisverweigerungsrecht in der Sozialen Arbeit, die aktuellen Reformbemühungen aus Praxis und Wissenschaft sowie die Auswirkungen des fehlenden Zeugnisverweigerungsrechts auf die Praxis aus Si

In der sozialpädagogischen Arbeit können Situationen entstehen, in denen Fachkräften vertrauliche Informationen zuteil werden, deren Schutz im Eigeninteresse der Adressat*innen oder des Staates liegen kann. Insbesondere die niedrigschwellige Arbeit mit Personen und Gruppen, die aus verschiedenen Gründen eine skeptische bis ablehnende Haltung gegenüber institutionellen Strukturen einnehmen – also mitunter auch Einrichtungen, für die Sozialarbeiter*innen tätig sind – oder mit Menschen, die beispielsweise aufgrund stoffgebundener Abhängigkeiten oder Verwicklungen in als extremistisch definierten Gruppen Strafverfolgung befürchten, erfordert von Sozialarbeiter*innen ein hohes Maß an Sensibilität für die eigene Rolle als Geheimnisträger nach § 203 Strafgesetzbuch (StGB). Gleiches gilt für Hilfesuchende, die sich an Opferberatungsstellen wenden und womöglich aus persönlichen Gründen ein Strafverfahren ablehnen, auch wenn sie selbst nicht beschuldigt wären. Die im Vertrauen von Adressat*innen erlangte Erkenntnis unterliegt zwar der Schweigepflicht, dies sichert den Sozialarbeiter*innen mit staatlicher Anerkennung im Strafverfahren allerdings kein Zeugnisverweigerungsrecht nach § 53 Strafprozessordnung (StPO) zu. Beides sind unterschiedliche rechtliche Regelungen, allerdings gibt es mit Ärzt*innen, Rechtsanwält*innen, Psycholog*innen, Journalist*innen, etc. Berufsgruppen, die in beiden Gesetzestexten berücksichtigt werden. Für Sozialarbeiter*innen gilt dieser Umstand nicht, ein Zeugnisverweigerungsrecht steht ihnen im Strafverfahren, mit Ausnahme von entsprechend qualifizierten Mitarbeiter*innen in Schwangerschaftsberatungsstellen sowie Beratungsstellen für Betäubungsmittelabhängige, nicht zu. Die vorliegende Masterarbeit beleuchtet die rechtliche und fachliche Aspekte des fehlenden Zeugnisverweigerungsrecht in der Sozialen Arbeit, die aktuellen Reformbemühungen aus Praxis und Wissenschaft sowie die Auswirkungen des fehlenden Zeugnisverweigerungsrechts auf die Praxis aus Si

The main objective of OPTIMORE is to optimize the crushing, milling and separation processing technologies for tungsten and tantalum. Optimization is realized by means of improved fast and flexible fine tuning production process control based on new software models, advanced sensing and deeper understanding of processes to increase yield and increase energy savings. The results explained in this work show this fulfilment with developed or simplified models for crushing, milling, gravity, magnetic and froth flotation separations. A new control system has been developed in this last part of the project, using the developed process models and advanced sensor systems. Validation of models in the simulation environment has been carried out. A pilot plant and real plant validation is planned for the end of the project. Knowledge transfer throughout the project between the Tungsten and Tantalum industry and the project partners has resulted in a strong relation between both which will continue to grow as the project concludes.

The main objective of OPTIMORE is to optimize the crushing, milling and separation processing technologies for tungsten and tantalum. Optimization is realized by means of improved fast and flexible fine tuning production process control based on new software models, advanced sensing and deeper understanding of processes to increase yield and increase energy savings. The results explained in this work show this fulfilment with developed or simplified models for crushing, milling, gravity, magnetic and froth flotation separations. A new control system has been developed in this last part of the project, using the developed process models and advanced sensor systems. Validation of models in the simulation environment has been carried out. A pilot plant and real plant validation is planned for the end of the project. Knowledge transfer throughout the project between the Tungsten and Tantalum industry and the project partners has resulted in a strong relation between both which will continue to grow as the project concludes.

In der sozialpädagogischen Arbeit können Situationen entstehen, in denen Fachkräften vertrauliche Informationen zuteil werden, deren Schutz im Eigeninteresse der Adressat*innen oder des Staates liegen kann. Insbesondere die niedrigschwellige Arbeit mit Personen und Gruppen, die aus verschiedenen Gründen eine skeptische bis ablehnende Haltung gegenüber institutionellen Strukturen einnehmen – also mitunter auch Einrichtungen, für die Sozialarbeiter*innen tätig sind – oder mit Menschen, die beispielsweise aufgrund stoffgebundener Abhängigkeiten oder Verwicklungen in als extremistisch definierten Gruppen Strafverfolgung befürchten, erfordert von Sozialarbeiter*innen ein hohes Maß an Sensibilität für die eigene Rolle als Geheimnisträger nach § 203 Strafgesetzbuch (StGB). Gleiches gilt für Hilfesuchende, die sich an Opferberatungsstellen wenden und womöglich aus persönlichen Gründen ein Strafverfahren ablehnen, auch wenn sie selbst nicht beschuldigt wären. Die im Vertrauen von Adressat*innen erlangte Erkenntnis unterliegt zwar der Schweigepflicht, dies sichert den Sozialarbeiter*innen mit staatlicher Anerkennung im Strafverfahren allerdings kein Zeugnisverweigerungsrecht nach § 53 Strafprozessordnung (StPO) zu. Beides sind unterschiedliche rechtliche Regelungen, allerdings gibt es mit Ärzt*innen, Rechtsanwält*innen, Psycholog*innen, Journalist*innen, etc. Berufsgruppen, die in beiden Gesetzestexten berücksichtigt werden. Für Sozialarbeiter*innen gilt dieser Umstand nicht, ein Zeugnisverweigerungsrecht steht ihnen im Strafverfahren, mit Ausnahme von entsprechend qualifizierten Mitarbeiter*innen in Schwangerschaftsberatungsstellen sowie Beratungsstellen für Betäubungsmittelabhängige, nicht zu. Die vorliegende Masterarbeit beleuchtet die rechtliche und fachliche Aspekte des fehlenden Zeugnisverweigerungsrecht in der Sozialen Arbeit, die aktuellen Reformbemühungen aus Praxis und Wissenschaft sowie die Auswirkungen des fehlenden Zeugnisverweigerungsrechts auf die Praxis aus Si

The main objective of OPTIMORE is to optimize the crushing, milling and separation processing technologies for tungsten and tantalum. Optimization is realized by means of improved fast and flexible fine tuning production process control based on new software models, advanced sensing and deeper understanding of processes to increase yield and increase energy savings. The results explained in this work show this fulfilment with developed or simplified models for crushing, milling, gravity, magnetic and froth flotation separations. A new control system has been developed in this last part of the project, using the developed process models and advanced sensor systems. Validation of models in the simulation environment has been carried out. A pilot plant and real plant validation is planned for the end of the project. Knowledge transfer throughout the project between the Tungsten and Tantalum industry and the project partners has resulted in a strong relation between both which will continue to grow as the project concludes.

The main objective of OPTIMORE is to optimize the crushing, milling and separation processing technologies for tungsten and tantalum. Optimization is realized by means of improved fast and flexible fine tuning production process control based on new software models, advanced sensing and deeper understanding of processes to increase yield and increase energy savings. The results explained in this work show this fulfilment with developed or simplified models for crushing, milling, gravity, magnetic and froth flotation separations. A new control system has been developed in this last part of the project, using the developed process models and advanced sensor systems. Validation of models in the simulation environment has been carried out. A pilot plant and real plant validation is planned for the end of the project. Knowledge transfer throughout the project between the Tungsten and Tantalum industry and the project partners has resulted in a strong relation between both which will continue to grow as the project concludes.

In der sozialpädagogischen Arbeit können Situationen entstehen, in denen Fachkräften vertrauliche Informationen zuteil werden, deren Schutz im Eigeninteresse der Adressat*innen oder des Staates liegen kann. Insbesondere die niedrigschwellige Arbeit mit Personen und Gruppen, die aus verschiedenen Gründen eine skeptische bis ablehnende Haltung gegenüber institutionellen Strukturen einnehmen – also mitunter auch Einrichtungen, für die Sozialarbeiter*innen tätig sind – oder mit Menschen, die beispielsweise aufgrund stoffgebundener Abhängigkeiten oder Verwicklungen in als extremistisch definierten Gruppen Strafverfolgung befürchten, erfordert von Sozialarbeiter*innen ein hohes Maß an Sensibilität für die eigene Rolle als Geheimnisträger nach § 203 Strafgesetzbuch (StGB). Gleiches gilt für Hilfesuchende, die sich an Opferberatungsstellen wenden und womöglich aus persönlichen Gründen ein Strafverfahren ablehnen, auch wenn sie selbst nicht beschuldigt wären. Die im Vertrauen von Adressat*innen erlangte Erkenntnis unterliegt zwar der Schweigepflicht, dies sichert den Sozialarbeiter*innen mit staatlicher Anerkennung im Strafverfahren allerdings kein Zeugnisverweigerungsrecht nach § 53 Strafprozessordnung (StPO) zu. Beides sind unterschiedliche rechtliche Regelungen, allerdings gibt es mit Ärzt*innen, Rechtsanwält*innen, Psycholog*innen, Journalist*innen, etc. Berufsgruppen, die in beiden Gesetzestexten berücksichtigt werden. Für Sozialarbeiter*innen gilt dieser Umstand nicht, ein Zeugnisverweigerungsrecht steht ihnen im Strafverfahren, mit Ausnahme von entsprechend qualifizierten Mitarbeiter*innen in Schwangerschaftsberatungsstellen sowie Beratungsstellen für Betäubungsmittelabhängige, nicht zu. Die vorliegende Masterarbeit beleuchtet die rechtliche und fachliche Aspekte des fehlenden Zeugnisverweigerungsrecht in der Sozialen Arbeit, die aktuellen Reformbemühungen aus Praxis und Wissenschaft sowie die Auswirkungen des fehlenden Zeugnisverweigerungsrechts auf die Praxis aus Si

In bacteria, the regulation of gene expression by cis-acting transcriptional riboswitches located in the 5'-untranslated regions of messenger RNA requires the temporal synchronization of RNA synthesis and ligand binding-dependent conformational refolding. Ligand binding to the aptamer domain of the riboswitch induces premature termination of the mRNA synthesis of ligand-associated genes due to the coupled formation of 3'-structural elements acting as terminators. To date, there has been no high resolution structural description of the concerted process of synthesis and ligand-induced restructuring of the regulatory RNA element. Here, we show that for the guanine-sensing xpt-pbuX riboswitch from Bacillus subtilis, the conformation of the full-length transcripts is static: it exclusively populates the functional off-state but cannot switch to the on-state, regardless of the presence or absence of ligand. We show that only the combined matching of transcription rates and ligand binding enables transcription intermediates to undergo ligand-dependent conformational refolding.

Peer Reviewed, Postprint (published version)

Froth flotation is a separation process which plays a major role in the mining industry. It is essentially employed to recover a vast array of different valuable commodities such as rare earth minerals essential to the manufacture of high-tech products. Owing to its simplicity, the process is also widely used for the de-inking of recycled paper fibres and for the removal of pollutants from waste water. The flotation process essentially relies on the attachment of solid particles on the surface of gas bubbles immersed in water. The present study seeks to investigate the effect of the particle shape on the attachment mechanism. Using an in-house optical micro-bubble sensor the approach, the sliding and the adhesion of micron milled glass fibres on the surface of a stationary air bubble immersed in stagnant water is thoroughly investigated. The translational and rotational velocities were measured for fibres of various aspect ratios. The results are compared with a theoretical model and with experimental data obtained with spherical glass beads. It is found that the fibre orientation during the sliding motion largely depends on the collision area. Upon collision near the upstream pole of the gas bubble the major axis of the fibre aligns with the local bubble surface (tangential fibre alignment). If collision occurs at least 30° further downstream only head of the fibre is in contact with the gas–liquid interface (radial fibre alignment).

Systems with strong spin-orbit coupling are of particular interest in solid state physics as an avenue for observing and manipulating spin physics using standard electrical techniques. This dissertation focuses on the characteristics of elemental bismuth (Bi), which exhibits some of the strongest intrinsic spin-orbit coupling of all elements, and InSb, which exhibits some of the strongest intrinsic spin-orbit coupling of all compound semiconductors. The experiments performed study the quantum transport signatures of nano- and micron-scale lithographically defined devices as well as spin-orbit coupled material/ferromagnet interfaces. All Bi structures are fabricated from Bi thin "films, and hence a detailed analysis of the characteristics of Bi "film growth by thermal evaporation is provided. Morphologically and electrically high quality "films are grown using a two stage deposition procedure. The phase and spin coherence of Bi geometries constrained in one, two, and three dimensions are systematically studied by analysis of the weak antilocalization transport signature, a quantum interference phenomenon sensitive to spin-orbit coupling. The "findings indicate that the phase coherence scales proportionally to the limiting dimension of the structure for sizes less than 500 nm. Specifically, in Bi wires, the phase coherence length is approximately as long as the wire width. Dephasing due to quantum confinement e"ffects limit the phase coherence in small Bi structures, impairing the observation of controlled interference phenomena in nano-scale Bi rings. The spin coherence length is independent of dimensional constraint by the film thickness, but increases significantly as the lateral dimensions, such as wire width, are constrained. This is a consequence of the quantum transport contribution from the strongly spin-orbit coupled Bi(001) surface state. To probe the Bi surface state further, Bi/CoFe junctions are fabricated. The anisotropic magnetoresistance of the Co

Systems with strong spin-orbit coupling are of particular interest in solid state physics as an avenue for observing and manipulating spin physics using standard electrical techniques. This dissertation focuses on the characteristics of elemental bismuth (Bi), which exhibits some of the strongest intrinsic spin-orbit coupling of all elements, and InSb, which exhibits some of the strongest intrinsic spin-orbit coupling of all compound semiconductors. The experiments performed study the quantum transport signatures of nano- and micron-scale lithographically defined devices as well as spin-orbit coupled material/ferromagnet interfaces. All Bi structures are fabricated from Bi thin "films, and hence a detailed analysis of the characteristics of Bi "film growth by thermal evaporation is provided. Morphologically and electrically high quality "films are grown using a two stage deposition procedure. The phase and spin coherence of Bi geometries constrained in one, two, and three dimensions are systematically studied by analysis of the weak antilocalization transport signature, a quantum interference phenomenon sensitive to spin-orbit coupling. The "findings indicate that the phase coherence scales proportionally to the limiting dimension of the structure for sizes less than 500 nm. Specifically, in Bi wires, the phase coherence length is approximately as long as the wire width. Dephasing due to quantum confinement e"ffects limit the phase coherence in small Bi structures, impairing the observation of controlled interference phenomena in nano-scale Bi rings. The spin coherence length is independent of dimensional constraint by the film thickness, but increases significantly as the lateral dimensions, such as wire width, are constrained. This is a consequence of the quantum transport contribution from the strongly spin-orbit coupled Bi(001) surface state. To probe the Bi surface state further, Bi/CoFe junctions are fabricated. The anisotropic magnetoresistance of the Co

Remote sensing systems exploit optical properties to gain information about a target. In the majority of the cases, this is done by exploiting the spectral domain. Only little effort is spend on looking for alternatives. The idea, that is investigated in this study, is to take advantage of the bidirectional reflectance which may carry information about the type of material, of which the target is composed. This method may be interesting especially for urban regions, where targets with different inclinations and orientations are distributed on a small area. A camera, which views two targets of the same material receives different fluxes according to the inclination of each target. That can disturb a classification process that is based on spectral information only, and does not take into account bidirectional reflectances. As for spectral data, bidirectional reflectance data is available for many types of materials. However, data sets are mostly restricted to incidence and reflection zenith angles of 60°. Therefore, to start with, measurements are conducted to acquire data which covers the whole upper hemisphere of a sample, i.e. a solid angle of 2pi. For this first phase, the goniometer available at ONERA in Toulouse is used, which, as well, is restricted to 60° zenith angle. An inclination wedge is used in order to measure angles up to a zenith angle of 80°. Limitations of this method are found. Seven real-world urban samples have been measured respecting the limitations of the measurement method. They represent well the diversity of materials which can be found in a city. Surprinsingly, for some of the samples, measurements show an increase in reflectance in the forward direction for grazing zenith angles. Three of the seven data sets are fitted to recent successful BRDF models. A model which is able to successfully describe BRDFs of urban materials has not been found. However, the model developed by R.L. Cook and K.E. Torrance describes the above mentioned effect, Validerat; 20101217 (root)

Schlüsselseiten aus dem Exemplar der BSB München: 4 Diss. 144, Vorlageform des Erscheinungsvermerks: Wittenbergae, Literis Christiani Schrödteri, Acad. Typ.