578 research outputs found
Ab initio spin-flip conductance of hydrogenated graphene nanoribbons: Spin-orbit interaction and scattering with local impurity spins
We calculate the spin-dependent zero-bias conductance in
armchair graphene nanoribbons with hydrogen adsorbates employing a DFT-based ab
initio transport formalism including spin-orbit interaction. We find that the
spin-flip conductance can reach the same order of
magnitude as the spin-conserving one, , due to
exchange-mediated spin scattering. In contrast, the genuine spin-orbit
interaction appears to play a secondary role, only
Ab initio quantum transport through armchair graphene nanoribbons: Streamlines in the current density
We calculate the local current density in pristine armchair graphene
nanoribbons (AGNRs) with varying width, , employing a
density-functional-theory-based ab initio transport formalism. We observe very
pronounced current patterns (streamlines) with threefold periodicity in
. They arise as a consequence of quantum confinement in the
transverse flow direction. Neighboring streamlines are separated by stripes of
almost vanishing flow. As a consequence, the response of the current to
functionalizing adsorbates is very sensitive to their placement: adsorbates
located within the current filaments lead to strong backscattering, while
adsorbates placed in other regions have almost no impact at all.Comment: 7 pages, 11 figure
Ab initio simulations of local current densities in mesoscopic films: Current vortices in functionalized graphene nanoribbons
This thesis presents DFT transport simulations of the local current density in functionalized graphene nanoribbons. The main results are current vortices which exceed the average through current significantly. Such current vortices are a source of orbital magnetism
Neue Ansätze fßr die funktionale Analyse von IGF-Effekten in vivo und vitro
Die Mitglieder des IGF-Systems regulieren das Wachstum auf unterschiedlichen Ebenen. In der Vergangenheit zog man zur Beschreibung des IGF-Systems ßberwiegend absolute Konzentrationen einzelner Hormone heran. Nach aktuellem Verständnis rßckt fßr die Beschreibung des IGF-Systems jedoch die Analyse der biologischen Aktivität in den Vordergrund. In der Arbeit wird die Interaktion mehrerer Faktoren zur Beschreibung der Wachstumsregulation in auf Wachstum selektierten und in transgenen Mauslinien stärker berßcksichtigt. Des Weiteren wird ein Bioassay fßr die In-vitro-Analyse mit vorgestellt.The members of the IGF system regulate growth at different levels. In the past, absolute concentrations of individual hormones were mainly used to describe the IGF system. According to current understanding, however, the analysis of the biological activity comes to the foreground for the description of the IGF system. In this work, the interaction of several factors is given greater consideration for the description of growth regulation in mouse lines selected for growth and in transgenic mouse lines. Furthermore, a bio-assay for in vitro analysis is presented
Emulating 802.11B And I/O Automata
The distributed systems solution to the World Wide Web is defined not only by the improvement of telephony, but also by the key need for replication. In our research, we validate the emulation of redundancy, which embodies the confusing principles of electrical engineering. In this paper we probe how 802.11b can be applied to the development of replication
Hazard uncertainty and related damage potentials of extra-tropical storms
Extra--tropical winter windstorms are among the most loss--intensive natural hazards in Europe. This thesis is dedicated to advance the understanding of these hazardous events and their uncertainty in various aspects. These aspects include the serial clustering and spatial variability of storm events, the seasonal predictability of extreme wind speeds associated with windstorms and an impact assessment of windstorms both in a climatological as well as from a loss--related perspective. The recurring element in all studies are large--scale drivers (e.g. North Atlantic Oscillation - NAO) which are linked to different features of extra--tropical windstorms, e.g. the inter--annual variability. It can be shown that large--scale drivers are able to explain a considerable amount of variability of windstorms. Seasonal forecast ensemble hindcasts are used to create a physical consistent virtual reality of more than 1500 years. Thus, the uncertainty of these extreme events can be estimated more accurately compared to using century--long reanalysis. This large sample size can also be used to estimate potential extremes with respect to intensity and severity of windstorms more accurately. The findings of these studies are presented in five scientific papers which are included as five chapters in this submitted thesis
MakroĂÂśkonomische Effekte von nachwachsenden Rohstoffen
The results of a current study point out the macroeconomic effects associated with the use and production of renewable resources (NAWARO) in Germany. It focuses on the direct and indirect employment effects in the NAWARO market segments biofuels, energy/electricity, chemical commodities and materials. Supply quantities of renewable resources and agricultural area in Germany required by the industrial production in the different market segments and associated employment effects in the German agricultural sector are also analyzed. Above all, if Germany succeeds to be a lead market in certain NAWARO market segments while retaining agricultural and industrial value chains in Germany considerable employment potentials emerge.renewable resources, new technologies, employment potentials, lead markets, scenarios, Labor and Human Capital, Resource /Energy Economics and Policy,
Psychoeducation: A Basic Psychotherapeutic Intervention for Patients With Schizophrenia and Their Families
Psychoeducation was originally conceived as a composite of numerous therapeutic elements within a complex family therapy intervention. Patients and their relatives were, by means of preliminary briefing concerning the illness, supposed to develop a fundamental understanding of the therapy and further be convinced to commit to more long-term involvement. Since the mid 1980s, psychoeducation in German-speaking countries has evolved into an independent therapeutic program with a focus on the didactically skillful communication of key information within the framework of a cognitive-behavioral approach. Through this, patients and their relatives should be empowered to understand and accept the illness and cope with it in a successful manner. Achievement of this basic-level competency is considered to constitute an âobligatory-exerciseâ program upon which additional âvoluntary-exerciseâ programs such as individual behavioral therapy, self-assertiveness training, problem-solving training, communication training, and further family therapy interventions can be built. Psychoeducation looks to combine the factor of empowerment of the affected with scientifically founded treatment expertise in as efficient a manner as possible. A randomized multicenter study based in Munich showed that within a 2-year period such a program was related to a significant reduction in rehospitalization rates from 58% to 41% and also a shortening of intermittent days spent in hospital from 78 to 39 days. Psychoeducation, in the form of an obligatory-exercise program, should be made available to all patients suffering from a schizophrenic disorder and their families
Practical application of AAPM Report 270 in display quality assurance: A report of Task Group 270
Published in January 2019, AAPM Report 270 provides an update to the recommendations of the AAPM\u27s TG18 report. Report 270 provides new definitions of display types, updated testing patterns, and revised performance standards for the modern, flat-panel displays used as part of medical image acquisition and review. The focus of the AAPM report is on consistent image quality and appearance, and how to establish a quality assurance program to achieve those two goals. This work highlights some of the key takeaways of AAPM Report 270 and makes comparisons with existing recommendations from other references. It also provides guidance for establishing a display quality assurance program for different-sized institutions. Finally, it describes future challenges for display quality assurance and what work remains
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