University Wrzburg

Schönau am Königssee, Germany

University Wrzburg

Schönau am Königssee, Germany
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Munsch M.,CEA Grenoble | Claudon J.,CEA Grenoble | Malik N.S.,CEA Grenoble | Gilbert K.,CEA Grenoble | And 11 more authors.
Applied Physics Letters | Year: 2012

We demonstrate room temperature, continuous wave lasing of laser diodes based on AlGaAs whispering gallery mode (WGM) resonators (microcylinder and microring) embedding a quantum dot (QD) active layer. Using InGaAlAs QDs, high-Q (>60 000) lasing modes are observed around 910 nm, up to 50°C. Lasing with similar performance is obtained around 1230 nm, using InAs QDs. Furthermore, we show that the current injection in the active part of the device is improved in ring resonators, leading to threshold currents of approximately 4 mA for a device with 80 μm diameter. This geometry also suppresses WGMs with a high radial order, thus simplifying the lasing spectra. In these conditions, stable single-mode and two-color lasing can be obtained. © 2012 American Institute of Physics.

This systematic literature review evaluates the effectiveness of patient and parental education in the rehabilitative treatment of children and adolescents with atopic dermatitis. All relevant databases were used to accumulate, analyze, and evaluate guidelines, meta- analyses, reviews as well as primary studies dealing with patient or parental education for children and adolescents with atopic dermatitis. In all, 11 methodically sound studies were selected. In the treatment of atopic dermatitis in children and adolescents patient and parental education programs lead to an improvement in all age groups in terms of symptom reduction and significant improvements in quality of life scores experienced by families. Challenges regarding the development of evidence-based treatment standards for children and adolescent rehabilitation are highlighted. © Springer-Verlag 2010.

Reiserer A.A.,University Wrzburg | Huang J.-S.,University Wrzburg | Hecht B.,University Wrzburg | Brixner T.,University Wrzburg
Optics Express | Year: 2010

Numerical simulations and an analytic approach based on transmission line theory are used to design splitters for nano-plasmonic signal processing that allow to arbitrarily adjust the ratio of transmission from an input into two different output arms. By adjusting the geometrical parameters of the structure, either a high bandwidth or a sharp transmission resonance is obtained. Switching between the two arms can be achieved by modulating the effective refractive index of the waveguide. Employing the instantaneous Kerr effect, switching rates in the THz regime are potentially feasible. The suggested devices are of interest for future applications in nanoplasmonic information processing. © 2010 Optical Society of America.

Gross H.,University Wrzburg | Gross H.,Rutgers University | Bansal N.,Rutgers University | Kim Y.-S.,Rutgers University | Oh S.,Rutgers University
Journal of Applied Physics | Year: 2011

We report how argon bombardment induces metallic states on the surface of insulating SrTiO3 at different temperatures by combining in situ conductance measurements and model calculations. At cryogenic temperatures, ionic bombardment created a thin-but much thicker than the argon-penetration depth-steady-state oxygen-vacant layer, leading to a highly-concentric metallic state. Near room temperatures, however, significant thermal diffusion occurred and the metallic state continuously diffused into the bulk, leaving only low concentration of electron carriers on the surface. Analysis of the discrepancy between the experiments and the models also provided evidence for vacancy clustering, which seems to occur during any vacancy formation process and affects the observed conductance. © 2011 American Institute of Physics.

Bar M.,Helmholtz Center Berlin | Bar M.,University of Nevada, Las Vegas | Schubert B.-A.,Helmholtz Center Berlin | Marsen B.,Helmholtz Center Berlin | And 6 more authors.
Applied Physics Letters | Year: 2011

Air-exposed Cu2ZnSnS4 (CZTS) thin-film solar cell absorbers have been investigated by surface-sensitive x-ray photoelectron and x-ray-excited Auger electron spectroscopy, as well as by bulk-sensitive energy dispersive x-ray spectroscopy. We find a native surface oxidation of (mainly) tin, but also (to a lesser extent) of zinc and sulfur as well as evidence for a Cu-poor region at the surface of the absorber, best described by a Cu-free Zn-Sn-S surface layer. © 2011 American Institute of Physics.

Buhmann H.,University Wrzburg
Journal of Applied Physics | Year: 2011

In a two-dimensional system the quantum spin Hall effect (QSHE) state is characterized by an insulating bulk and two counter-propagating helical edge states. These edge channels are protected by time reversal symmetry and spin currents propagate without dissipation. It was shown that HgTe-based quantum well structures are the most suitable candidates for its experimental realization. Here, the experimental requirements are discussed which lead to the observation of quantized edge channel transport which is one of the main signatures of the QSHE. Experiments will be presented which demonstrate the stability of the quantized conductance and its nonlocal character. Furthermore, evidence for the spin polarization of the QSHE edge channels is shown in an all-electrical measurement which demonstrates the potential of the QSHE for spin injection and detection applications in spintronics. © 2011 American Institute of Physics.

Gross H.,University Wrzburg | Oh S.,Rutgers University
Applied Physics Letters | Year: 2011

We show that ionic-bombardment leads to noticeable resistive memory effect on pure SrTiO 3 (STO). In an Ar-bombarded STO crystal, two orders of resistance difference was observed between the high and low resistive states. We found that Ar-bombardment is more efficient than thermal-reduction in creating memory-effective oxygen vacancies. One of the advantages of the ionic-bombardment scheme is that it can be easily combined with lithographic processes to create spatially selective memory effect. © 2011 American Institute of Physics.

Ilchmann A.,TU Ilmenau | Wirth F.,University Wrzburg
At-Automatisierungstechnik | Year: 2013

We discuss the concept of 'minimum phase' for scalar semi Hurwitz transfer functions. The latter are rational functions where the denominator polynomial has its roots in the closed left half complex plane. In the present note, minimum phase is defined in terms of the derivative of the argument function of the transfer function. The main tool to characterize minimum phase is the Hurwitz reflection. The factorization of a weakly stable transfer function into an all-pass and a minimum phase system leads to the result that any semi Hurwitz transfer function is minimum phase if, and only if, its numerator polynomial is semi Hurwitz. To characterize the zero dynamics, we use the Byrnes-Isidori form in the time domain and the internal loop form in the frequency domain. The uniqueness of both forms is shown. This is used to show in particular that asymptotic stable zero dynamics of a minimal realization of a transfer function yields minimum phase, but not vice versa. © Oldenbourg Wissenschaftsverlag.

Evita M.,Bandung Institute of Technology | Evita M.,University Wrzburg | Djamal M.,Bandung Institute of Technology | Zimanowski B.,University Wrzburg | Schilling K.,University Wrzburg
Proceedings - 2015 4th International Conference on Instrumentation, Communications, Information Technology and Biomedical Engineering, ICICI-BME 2015 | Year: 2015

A new combination between Wireless Sensor Network (WSN), mobile robot and satellite technology for Indonesian volcano monitoring system, Mobile Monitoring System for Indonesian Volcano (MONICA) has been developed. This system divided into two modes: fixed-mode and mobile mode. The first mode has shown a good performance. For a small event of volcano activity, the system only uses power 1 million times lower than the power from existing equipment (seismometer). Bandwidth management technique results in 1 normalized throughput with average delay 6 ms as perfect as quality management technique which detects no false alarm and 100% delivery rate. © 2015 IEEE.

Muthig M.,University Wrzburg | Hebestreit A.,University Wrzburg | Ziegler U.,Missionsarztliche Klinik GmbH | Seidler M.,University of Heidelberg | And 2 more authors.
Medical Mycology | Year: 2010

It is still controversial as to whether Candida spp. are transient or persistent colonizers of the respiratory tract of cystic fibrosis (CF) patients. We conducted a prospective study of 56 CF patients over a 30 month period to assess the distribution and persistence of different Candida spp. In vitro antifungal susceptibility testing was performed and the C. albicans isolates were typed with CARE-2 hybridization and other Candida spp. by RAPD-PCR for persistence and transmission. We found that the mean persistence of the most frequent Candida spp. was ≥ 9 months. In patients from whom more than 10 isolates were recovered, we noted that at least 30% were genetically related and transmission of C. albicans in siblings was observed. The majority of all isolates were susceptible to all antifungals tested. We concluded that there was long-term persistence of Candida in the respiratory tract of CF patients and that transmission between siblings may be one possible means of acquisition. Whether long-term colonization with Candida strains can contribute to the chronic infection and inflammation in the CF lung requires further investigation. © 2010 ISHAM.

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