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310 results on '"Ulbrich, R."'

1. The CARMENES search for exoplanets around M dwarfs - HD 147379b: A nearby Neptune in the temperate zone of an early-M dwarf

Author

Reiners, A., Ribas, I., Zechmeister, M., Caballero, J. A., Trifonov, T., Dreizler, S., Morales, J. C., Tal-Or, L., Lafarga, M., Quirrenbach, A., Amado, P. J., Kaminski, A., Jeffers, S. V., Aceituno, J., Béjar, V. J. S., Guàrdia, J., Guenther, E. W., Hagen, H. -J., Montes, D., Passegger, V. M., Seifert, W., Schweitzer, A., Cortés-Contreras, M., Abril, M., Alonso-Floriano, F. J., Eiff, M. Ammler-von, Antona, R., Anglada-Escudé, G., Anwand-Heerwart, H., Arroyo-Torres, B., Azzaro, M., Baroch, D., Barrado, D., Bauer, F. F., Becerril, S., Benítez, D., Berdiñas, Z. M., Bergond, G., Blümcke, M., Brinkmöller, M., del Burgo, C., Cano, J., Vázquez, M. C. Cárdenas, Casal, E., Cifuentes, C., Claret, A., Colomé, J., Czesla, S., Díez-Alonso, E., Feiz, C., Fernández, M., Ferro, I. M., Fuhrmeister, B., Galadí-Enríquez, D., Garcia-Piquer, A., Vargas, M. L. García, Gesa, L., Galera, V. Gómez, Hernández, J. I. González, González-Peinado, R., Grözinger, U., Grohnert, S., Guijarro, A., de Guindos, E., Gutiérrez-Soto, J., Hatzes, A. P., Hauschildt, P. H., Hedrosa, R. P., Helmling, J., Henning, Th., Hermelo, I., Arabí, R. Hernández, Castaño, L. Hernández, Hernando, F. Hernández, Herrero, E., Huber, A., Huke, P., Johnson, E. N., de Juan, E., Kim, M., Klein, R., Klüter, J., Klutsch, A., Kürster, M., Labarga, F., Lamert, A., Lampón, M., Lara, L. M., Laun, W., Lemke, U., Lenzen, R., Launhardt, R., del Fresno, M. López, López-González, M. J., López-Puertas, M., Salas, J. F. López, López-Santiago, J., Luque, R., Madinabeitia, H. Magán, Mall, U., Mancini, L., Mandel, H., Marfil, E., Molina, J. A. Marín, Fernández, D. Maroto, Martín, E. L., Martín-Ruiz, S., Marvin, C. J., Mathar, R. J., Mirabet, E., Moreno-Raya, M. E., Moya, A., Mundt, R., Nagel, E., Naranjo, V., Nortmann, L., Nowak, G., Ofir, A., Oreiro, R., Pallé, E., Panduro, J., Pascual, J., Pavlov, A., Pedraz, S., Pérez-Calpena, A., Medialdea, D. Pérez, Perger, M., Perryman, M. A. C., Pluto, M., Rabaza, O., Ramón, A., Rebolo, R., Redondo, P., Reffert, S., Reinhart, S., Rhode, P., Rix, H. -W., Rodler, F., Rodríguez, E., Rodríguez-López, C., Trinidad, A. Rodríguez, Rohloff, R. -R., Rosich, A., Sadegi, S., Sánchez-Blanco, E., Carrasco, M. A. Sánchez, Sánchez-López, A., Sanz-Forcada, J., Sarkis, P., Sarmiento, L. F., Schäfer, S., Schmitt, J. H. M. M., Schiller, J., Schöfer, P., Solano, E., Stahl, O., Strachan, J. B. P., Stürmer, J., Suárez, J. C., Tabernero, H. M., Tala, M., Tulloch, S. M., Ulbrich, R. -G., Veredas, G., Linares, J. I. Vico, Vilardell, F., Wagner, K., Winkler, J., Wolthoff, V., Xu, W., Yan, F., and Osorio, M. R. Zapatero

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

We report on the first star discovered to host a planet detected by radial velocity (RV) observations obtained within the CARMENES survey for exoplanets around M dwarfs. HD 147379 ($V = 8.9$ mag, $M = 0.58 \pm 0.08$ M$_{\odot}$), a bright M0.0V star at a distance of 10.7 pc, is found to undergo periodic RV variations with a semi-amplitude of $K = 5.1\pm0.4$ m s$^{-1}$ and a period of $P = 86.54\pm0.06$ d. The RV signal is found in our CARMENES data, which were taken between 2016 and 2017, and is supported by HIRES/Keck observations that were obtained since 2000. The RV variations are interpreted as resulting from a planet of minimum mass $m_{\rm p}\sin{i} = 25 \pm 2$ M$_{\oplus}$, 1.5 times the mass of Neptune, with an orbital semi-major axis $a = 0.32$ au and low eccentricity ($e < 0.13$). HD 147379b is orbiting inside the temperate zone around the star, where water could exist in liquid form. The RV time-series and various spectroscopic indicators show additional hints of variations at an approximate period of 21.1d (and its first harmonic), which we attribute to the rotation period of the star., Comment: accepted for publication as A&A Letter

Published
2017
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2. The CARMENES search for exoplanets around M dwarfs: High-resolution optical and near-infrared spectroscopy of 324 survey stars

Author

Reiners, A., Zechmeister, M., Caballero, J. A., Ribas, I., Morales, J. C., Jeffers, S. V., Schöfer, P., Tal-Or, L., Quirrenbach, A., Amado, P. J., Kaminski, A., Seifert, W., Abril, M., Aceituno, J., Alonso-Floriano, F. J., Eiff, M. Ammler-von, Antona, R., Anglada-Escudé, G., Anwand-Heerwart, H., Arroyo-Torres, B., Azzaro, M., Baroch, D., Barrado, D., Bauer, F. F., Becerril, S., Béjar, V. J. S., Benítez, D., Berdiñas, Z. M., Bergond, G., Blümcke, M., Brinkmöller, M., del Burgo, C., Cano, J., Vázquez, M. C. Cárdenas, Casal, E., Cifuentes, C., Claret, A., Colomé, J., Cortés-Contreras, M., Czesla, S., Díez-Alonso, E., Dreizler, S., Feiz, C., Fernández, M., Ferro, I. M., Fuhrmeister, B., Galadí-Enríquez, D., Garcia-Piquer, A., Vargas, M. L. García, Gesa, L., Gómez, V., Galera, Hernández, J. I. González, González-Peinado, R., Grözinger, U., Grohnert, S., Guàrdia, J., Guenther, E. W., Guijarro, A., de Guindos, E., Gutiérrez-Soto, J., Hagen, H. -J., Hatzes, A. P., Hauschildt, P. H., Hedrosa, R. P., Helmling, J., Henning, Th., Hermelo, I., Arabí, R. Hernández, Castaño, L. Hernández, Hernando, F. Hernández, Herrero, E., Huber, A., Huke, P., Johnson, E., de Juan, E., Kim, M., Klein, R., Klüter, J., Klutsch, A., Kürster, M., Lafarga, M., Lamert, A., Lampón, M., Lara, L. M., Laun, W., Lemke, U., Lenzen, R., Launhardt, R., del Fresno, M. López, López-González, J., López-Puertas, M., Salas, J. F. López, López-Santiago, J., Luque, R., Madinabeitia, H. Magán, Mall, U., Mancini, L., Mandel, H., Marfil, E., Molina, J. A. Marín, Maroto, D., Fernández, Martín, E. L., Martín-Ruiz, S., Marvin, C. J., Mathar, R. J., Mirabet, E., Montes, D., Moreno-Raya, M. E., Moya, A., Mundt, R., Nagel, E., Naranjo, V., Nortmann, L., Nowak, G., Ofir, A., Oreiro, R., Pallé, E., Panduro, J., Pascual, J., Passegger, V. M., Pavlov, A., Pedraz, S., Pérez-Calpena, A., Medialdea, D. Pérez, Perger, M., Perryman, M. A. C., Pluto, M., Rabaza, O., Ramón, A., Rebolo, R., Redondo, P., Reffert, S., Reinhart, S., Rhode, P., Rix, H. -W., Rodler, F., Rodríguez, E., Rodríguez-López, C., Trinidad, A. Rodríguez, Rohloff, R. -R., Rosich, A., Sadegi, S., Sánchez-Blanco, E., Carrasco, M. A. Sánchez, Sánchez-López, A., Sanz-Forcada, J., Sarkis, P., Sarmiento, L. F., Schäfer, S., Schmitt, J. H. M. M., Schiller, J., Schweitzer, A., Solano, E., Stahl, O., Strachan, J. B. P., Stürmer, J., Suárez, J. C., Tabernero, H. M., Tala, M., Trifonov, T., Tulloch, S. M., Ulbrich, R. G., Veredas, G., Linares, J. I. Vico, Vilardell, F., Wagner, K., Winkler, J., Wolthoff, V., Xu, W., Yan, F., and Osorio, M. R. Zapatero

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the survey sample by publishing one CARMENES spectrum for each M dwarf. These spectra cover the wavelength range 520--1710nm at a resolution of at least $R > 80,000$, and we measure its RV, H$\alpha$ emission, and projected rotation velocity. We present an atlas of high-resolution M-dwarf spectra and compare the spectra to atmospheric models. To quantify the RV precision that can be achieved in low-mass stars over the CARMENES wavelength range, we analyze our empirical information on the RV precision from more than 6500 observations. We compare our high-resolution M-dwarf spectra to atmospheric models where we determine the spectroscopic RV information content, $Q$, and signal-to-noise ratio. We find that for all M-type dwarfs, the highest RV precision can be reached in the wavelength range 700--900nm. Observations at longer wavelengths are equally precise only at the very latest spectral types (M8 and M9). We demonstrate that in this spectroscopic range, the large amount of absorption features compensates for the intrinsic faintness of an M7 star. To reach an RV precision of 1ms$^{-1}$ in very low mass M dwarfs at longer wavelengths likely requires the use of a 10m class telescope. For spectral types M6 and earlier, the combination of a red visual and a near-infrared spectrograph is ideal to search for low-mass planets and to distinguish between planets and stellar variability. At a 4m class telescope, an instrument like CARMENES has the potential to push the RV precision well below the typical jitter level of 3-4ms$^{-1}$., Comment: accepted for publication in A&A, 13 pages plus 40 pages spectral atlas, first 10 atlas pages are reduced in quality to fit arXiv size limit; one CARMENES spectrum for each of the 324 stars is published in electronic format at http://carmenes.cab.inta-csic.es/

Published
2017
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3. A laser-lock concept to reach cm/s-precision in Doppler experiments with Fabry-Perot wavelength calibrators

Author

Reiners, A., Banyal, R. K., and Ulbrich, R. G.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

State-of-the-art Doppler experiments require wavelength calibration with precision at the cm/s level. A low-finesse Fabry-Perot interferometer (FPI) can provide a wavelength comb with a very large bandwidth as required for astronomical experiments, but unavoidable spectral drifts are difficult to control. Instead of actively controlling the FPI cavity, we propose to passively stabilize the interferometer and track the time-dependent cavity length drift externally. A dual-finesse cavity allows drift tracking during observation. The drift of the cavity length is monitored in the high-finesse range relative to an external standard: a single narrow transmission peak is locked to an external cavity diode laser and compared to an atomic frequency. Following standard locking schemes, tracking at sub-mm/s precision can be achieved. This is several orders of magnitude better than currently planned high-precision Doppler experiments. It allows freedom for relaxed designs rendering this approach particularly interesting for upcoming Doppler experiments. We also show that the large number of interference modes used in an FPI allows us to unambiguously identify the interference mode of each FPI transmission peak defining its absolute wavelength solution. The accuracy reached in each resonance with the laser concept is then defined by the cavity length that is determined from the one locked peak and by the group velocity dispersion. The latter can vary by several 100m/s over the relevant frequency range and severely limits the accuracy of individual peak locations. A potential way to determine the absolute peak positions is to externally measure the frequency of each individual peak with a laser frequency comb (LFC). Thus, the concept of laser-locked FPIs may be useful for applying the absolute accuracy of an LFC to astronomical spectrographs without the need for an LFC at the observatory., Comment: 9 pages, accepted for publication in A&A, abstract abbreviated

Published
2014
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4. Band structure related wave function symmetry of amphoteric Si dopants in GaAs

Author

Loth, S., Wenderoth, M., Teichmann, K., and Ulbrich, R. G.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Disordered Systems and Neural Networks
Abstract

Autocompensated Si-doped GaAs is studied with cross-sectional scanning tunneling spectroscopy (X-STS). The local electronic contrasts of substitutional Si(Ga) donors and Si(As) acceptors under the (110) cleavage plane are imaged with high resolution. Si(Ga) donor atoms exhibit radially symmetric contrasts. Si(As) acceptors have anisotropic features. The anisotropic acceptor contrasts are traced back to a tunnel process at the valence band edge. They reflect the probability density distribution of the localized acceptor hole state., Comment: 10 pages, 3 figures

Published
2007
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5. Influence of surface-related strain and electric field on acceptor wave functions in Zincblende semiconductors

Author

Loth, S., Wenderoth, M., and Ulbrich, R. G.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Disordered Systems and Neural Networks
Abstract

The spatial distribution of the local density of states (LDOS) at Mn acceptors near the (110) surface of p-doped InAs is investigated by Scanning Tunneling Microscopy (STM). The shapes of the acceptor contrasts for different dopant depths under the surface are analyzed. Acceptors located within the first ten subsurface layers of the semiconductor show a lower symmetry than expected from theoretical predictions of the bulk acceptor wave function. They exhibit a (001) mirror asymmetry. The degree of asymmetry depends on the acceptor atoms' depths. The measured contrasts for acceptors buried below the 10th subsurface layer closely match the theoretically derived shape. Two effects are able to explain the symmetry reduction: the strain field of the surface relaxation and the tip-induced electric field., Comment: 8 pages, 4 figures

Published
2007
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6. On the Connection of Anisotropic Conductivity to Tip Induced Space Charge Layers in Scanning Tunneling Spectroscopy of p-doped GaAs

Author

Loth, S., Wenderoth, M., Ulbrich, R. G., Malzer, S., and Döhler, G. H.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Disordered Systems and Neural Networks
Abstract

The electronic properties of shallow acceptors in p-doped GaAs{110} are investigated with scanning tunneling microscopy at low temperature. Shallow acceptors are known to exhibit distinct triangular contrasts in STM images for certain bias voltages. Spatially resolved I(V)-spectroscopy is performed to identify their energetic origin and behavior. A crucial parameter - the STM tip's work function - is determined experimentally. The voltage dependent potential configuration and band bending situation is derived. Ways to validate the calculations with the experiment are discussed. Differential conductivity maps reveal that the triangular contrasts are only observed with a depletion layer present under the STM tip. The tunnel process leading to the anisotropic contrasts calls for electrons to tunnel through vacuum gap and a finite region in the semiconductor., Comment: 11 pages, 8 figures

Published
2007
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7. On the Origin of Schottky Barriers in GaAs(110):Au contacts

Author

Reusch, T. C. G., Wenderoth, M., Winking, L., Quaas, N., and Ulbrich, R. G.

Subjects
Condensed Matter - Materials Science
Abstract

Scanning Tunnelling Spectroscopy of GaAs(110):Au Schottky contacts in cross-sectional configuration has been used to investigate the in-depth properties of the space charge layer as well as the interface region with nanometer resolution., Comment: withdrawn for major revisions

Published
2003

15. Pilot: sector- en grensoverschrijdend samenwerken voor innovatie

Author

Amador, M., Uijtewaal, A., Ulbrich, R., Bers, C. van, Amador, M., Uijtewaal, A., Ulbrich, R., and Bers, C. van

Abstract

Het Duits-Nederlandse project INTERREG-VA MEDUWA-Vecht(e) is onlangs afgerond. Het doel was de ontwikkeling van innovatieve methodieken om de emissie van humane en veterinaire medicijnen en antimicrobieel resistente micro-organismen naar bodem, oppervlakte- en grondwater te voorkomen. De MEDUWA-coalitie heeft in zeven van de tien schakels van de medicijnketen in totaal twaalf nieuwe gereedschappen voortgebracht voor de preventie, mitigatie, meting en monitoring van verontreiniging, alsmede simulatie, visualisatie en communicatie van oplossingen. Daarnaast heeft de sectoroverstijgende en grensoverschrijdende opzet voor samenwerking tussen partners uit meerdere niveau’s van de productketen in één enkel project zich in de praktijk bewezen.

Published
2021

21. CARMENES: high-resolution spectra and precise radial velocities in the red and infrared

Author

Quirrenbach, Andreas, primary, Amado, P. J., primary, Ribas, I., primary, Caballero, J. A., primary, Seifert, W., primary, Aceituno, J., primary, Azzaro, M., primary, Barrado, D., primary, Becerril, S., primary, Bèjar, V. J. S., primary, Benítez, D., primary, Brinkmöller, M., primary, Colomé, J., primary, Cortés-Contreras, M., primary, Czesla, S., primary, Frölich, K., primary, Galadí-Enríquez, D., primary, González Hernández, J. I., primary, González Peinado, R., primary, Guenther, E. W., primary, de Guindos, E., primary, Hagen, H.-J., primary, Henning, Th., primary, Hernández Castaño, L., primary, Herrero, E., primary, Hintz, D., primary, Jeffers, S. V., primary, Kaminski, A., primary, Klahr, H., primary, Marfil, E. G., primary, Martín, E. L., primary, Martín-Ruiz, S., primary, Mathar, R. J., primary, Montes, D., primary, Morales, J. C., primary, Nagel, E., primary, Pallé, E., primary, Pérez-Medialdea, D., primary, Perger, M., primary, Rebolo, R., primary, Reffert, S., primary, Rosich, A., primary, Sabotta, S., primary, Schäfer, S., primary, Schiller, J., primary, Schweitzer, A., primary, Solano, E., primary, Stahl, O., primary, Tala Pinto, M., primary, Trifonov, T., primary, Yan, F., primary, Zechmeister, M., primary, Abellán, F. J., primary, Abril, M., primary, Alonso-Floriano, F. J., primary, Ammler-von Eiff, M., primary, Anglada-Escudé, G., primary, Anwand-Heerwart, H., primary, Berdiñas, Z. M., primary, Bergondy, D., primary, del Burgo, C., primary, Cárdenas, M. C., primary, Casal, E., primary, Claret, A., primary, Ferro, I. M., primary, Gálvez-Ortiz, M. C., primary, Gesa, L., primary, Gómez Galera, V., primary, Guijarro, A., primary, Hedrosa, R. P., primary, Hermann, D., primary, Hermelo, I., primary, Hernández Arabí, R., primary, Hidalgo, D., primary, Huber, A., primary, Huber, K., primary, Kehr, M., primary, Klein, R., primary, Klüter, J., primary, Klutsch, A., primary, Labarga, F., primary, Labiche, N., primary, Lamert, A., primary, Lemke, U., primary, Lenzen, R., primary, Lizon, J.-L., primary, Lodieu, N., primary, López-Morales, M., primary, López Salas, J. F., primary, López-Santiago, J., primary, Martínez-Rodríguez, H., primary, Maroto Fernández, D., primary, Marvin, C. J., primary, Mirabet, E., primary, Moreno-Raya, M. E., primary, Moya, A., primary, Naranjo, V., primary, Pascual, J., primary, Pérez-Calpena, A., primary, Perryman, M. A. C., primary, Rohloff, R.-R., primary, Sánchez Carrasco, M. A., primary, Schmidt, C., primary, Strachan, J. B. P., primary, Tal-Or, L., primary, Tulloch, S. M., primary, Veredas, G., primary, Vilardell, F., primary, Wagner, K., primary, Zhao, Z., primary, Reiners, A., primary, Baroch, D., primary, Bauer, F., primary, Cardona Guillén, C., primary, Cifuentes, C., primary, Dreizler, S., primary, Fuhrmeister, B., primary, Hatzes, A. P., primary, Hauschildt, P. H., primary, Helmling, J., primary, Herbort, O., primary, Johnson, E. N., primary, de Juan, E., primary, Kürster, M., primary, Lafarga, M., primary, Sairam, L., primary, Lampón, M., primary, Lara, L. M., primary, Launhardt, R., primary, López del Fresno, M., primary, López-Puertas, M., primary, Luque, R., primary, Mandel, H., primary, Nortmann, L., primary, Nowak, G., primary, Passegger, V.-M., primary, Pavlov, A., primary, Pedraz, S., primary, Rodríguez, E., primary, Rodríguez López, C., primary, Sadegi, S., primary, Salz, M., primary, Sánchez-López, A., primary, Sanz-Forcada, J., primary, Sarkis, P., primary, Schmitt, J. H. M. M., primary, Schöfer, P., primary, Shulyak, D., primary, Zapatero Osorio, M. R., primary, Arroyo-Torres, B., primary, Blümcke, M., primary, Cano, J., primary, Carro, J., primary, Díez-Alonso, E., primary, Doellinger, M., primary, Dorda, R., primary, Feiz, C., primary, Fernández, M., primary, Gaisné, G., primary, Gallardo, I., primary, García-Piquer, A., primary, García-Vargas, M. L., primary, Garrido, R., primary, González-Álvarez, E., primary, González-Cuesta, L., primary, Grohnert, S., primary, Grözinger, U., primary, Guàrdia, J., primary, Hernández Hernando, F., primary, Holgado, G., primary, Huke, P., primary, Kim, M., primary, Laun, W., primary, Lázaro, F. J., primary, Llamas, M., primary, López González, M. J., primary, Magán Madinabeitia, H., primary, Mall, U., primary, Mancini, L., primary, Marín Molina, J. A., primary, Mundt, R., primary, Panduro, J., primary, Pluto, M., primary, Ramón, A., primary, Redondo, P., primary, Reinhart, S., primary, Rhode, P., primary, Rix, H.-W., primary, Rodler, F., primary, Sánchez-Blanco, E., primary, Sarmiento, L. F., primary, Storz, C., primary, Stürmer, J., primary, Suárez, J. C., primary, Tabernero, H. M., primary, Ulbrich, R.-G., primary, Vico Linares, J. L., primary, Vidal-Dasilva, M., primary, Winkler, J., primary, Wolthoff, V., primary, and Xu, W., primary

Published
2018
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22. The CARMENES search for exoplanets around M dwarfs

Author

Reiners, A., primary, Zechmeister, M., additional, Caballero, J. A., additional, Ribas, I., additional, Morales, J. C., additional, Jeffers, S. V., additional, Schöfer, P., additional, Tal-Or, L., additional, Quirrenbach, A., additional, Amado, P. J., additional, Kaminski, A., additional, Seifert, W., additional, Abril, M., additional, Aceituno, J., additional, Alonso-Floriano, F. J., additional, Ammler-von Eiff, M., additional, Antona, R., additional, Anglada-Escudé, G., additional, Anwand-Heerwart, H., additional, Arroyo-Torres, B., additional, Azzaro, M., additional, Baroch, D., additional, Barrado, D., additional, Bauer, F. F., additional, Becerril, S., additional, Béjar, V. J. S., additional, Benítez, D., additional, Berdinas̃, Z. M., additional, Bergond, G., additional, Blümcke, M., additional, Brinkmöller, M., additional, del Burgo, C., additional, Cano, J., additional, Cárdenas Vázquez, M. C., additional, Casal, E., additional, Cifuentes, C., additional, Claret, A., additional, Colomé, J., additional, Cortés-Contreras, M., additional, Czesla, S., additional, Díez-Alonso, E., additional, Dreizler, S., additional, Feiz, C., additional, Fernández, M., additional, Ferro, I. M., additional, Fuhrmeister, B., additional, Galadí-Enríquez, D., additional, Garcia-Piquer, A., additional, García Vargas, M. L., additional, Gesa, L., additional, Gómez Galera, V., additional, González Hernández, J. I., additional, González-Peinado, R., additional, Grözinger, U., additional, Grohnert, S., additional, Guàrdia, J., additional, Guenther, E. W., additional, Guijarro, A., additional, de Guindos, E., additional, Gutiérrez-Soto, J., additional, Hagen, H.-J., additional, Hatzes, A. P., additional, Hauschildt, P. H., additional, Hedrosa, R. P., additional, Helmling, J., additional, Henning, Th., additional, Hermelo, I., additional, Hernández Arabí, R., additional, Hernández Castaño, L., additional, Hernández Hernando, F., additional, Herrero, E., additional, Huber, A., additional, Huke, P., additional, Johnson, E. N., additional, de Juan, E., additional, Kim, M., additional, Klein, R., additional, Klüter, J., additional, Klutsch, A., additional, Kürster, M., additional, Lafarga, M., additional, Lamert, A., additional, Lampón, M., additional, Lara, L. M., additional, Laun, W., additional, Lemke, U., additional, Lenzen, R., additional, Launhardt, R., additional, López del Fresno, M., additional, López-González, J., additional, López-Puertas, M., additional, López Salas, J. F., additional, López-Santiago, J., additional, Luque, R., additional, Magán Madinabeitia, H., additional, Mall, U., additional, Mancini, L., additional, Mandel, H., additional, Marfil, E., additional, Marín Molina, J. A., additional, Maroto Fernández, D., additional, Martín, E. L., additional, Martín-Ruiz, S., additional, Marvin, C. J., additional, Mathar, R. J., additional, Mirabet, E., additional, Montes, D., additional, Moreno-Raya, M. E., additional, Moya, A., additional, Mundt, R., additional, Nagel, E., additional, Naranjo, V., additional, Nortmann, L., additional, Nowak, G., additional, Ofir, A., additional, Oreiro, R., additional, Pallé, E., additional, Panduro, J., additional, Pascual, J., additional, Passegger, V. M., additional, Pavlov, A., additional, Pedraz, S., additional, Pérez-Calpena, A., additional, Pérez Medialdea, D., additional, Perger, M., additional, Perryman, M. A. C., additional, Pluto, M., additional, Rabaza, O., additional, Ramón, A., additional, Rebolo, R., additional, Redondo, P., additional, Reffert, S., additional, Reinhart, S., additional, Rhode, P., additional, Rix, H.-W., additional, Rodler, F., additional, Rodríguez, E., additional, Rodríguez-López, C., additional, Rodríguez Trinidad, A., additional, Rohloff, R.-R., additional, Rosich, A., additional, Sadegi, S., additional, Sánchez-Blanco, E., additional, Sánchez Carrasco, M. A., additional, Sánchez-López, A., additional, Sanz-Forcada, J., additional, Sarkis, P., additional, Sarmiento, L. F., additional, Schäfer, S., additional, Schmitt, J. H. M. M., additional, Schiller, J., additional, Schweitzer, A., additional, Solano, E., additional, Stahl, O., additional, Strachan, J. B. P., additional, Stürmer, J., additional, Suárez, J. C., additional, Tabernero, H. M., additional, Tala, M., additional, Trifonov, T., additional, Tulloch, S. M., additional, Ulbrich, R. G., additional, Veredas, G., additional, Vico Linares, J. I., additional, Vilardell, F., additional, Wagner, K., additional, Winkler, J., additional, Wolthoff, V., additional, Xu, W., additional, Yan, F., additional, and Zapatero Osorio, M. R., additional

Published
2018
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30. Kurzvorträge und Poster zum Thema Schwangerschaftsabbruch

Author

Höbich, D., Brünig, R., Schmidt-Gollwitzer, K., Hoyme, U., Decker, K., Wilken, H., Eckardt, W., Peters, F. D., Hirsch, H. A., v. Trotha, A., Behrendt, M., Walz, K. A., Fischer, W. M., Ludwig, H., Höbich, D., Gaerret-Bleek, N., Granitzka, S., Siedentopf, H. -G., Nuripur, M., Mangold, S., Anderer, M., Schweppe, K. -W., Immand, H., Lueken, R. P., Gallinat, A., Lindemann, H. J., Kunz, J., Gerig, B., Sievers, S., Wiest, W., Dallenbach-Hellweg, G., Schleich, A., Mignon, P., Lippert, T. H., Peters, F. D., Kunz, S., Anderer, M., Rauskolb, R., Schiller, V., Maack, N., Bayer, H., Halle, H., Walz, K. A., Behrendt, M., Trotha, A. v., Fischer, W. M., Ludwig, H., Beck, A., Sterijev, K., Feichter, G. E., Tauber, P. F., Rosenthal, E., Nohlen, M., Ludwig, H., Sarembe, B., Lichtenegger, W., Lirmberger, M., Runte, K. P., Maas, D. H. A., Cornely, M., Weitzel, H., Hoppen, H. -O., Gethmann, U., Gethmann, U., Oberheuser, F., Schmidt-Gollwitzer, K., Schüssler, B., Schmidt-Gollwitzer, M., Schmidt-Gollwitzer, M., Schüssler, B., Schmidt-Gollwitzer, K., Steiner, H., Zahradnik, H. P., Robrecht, D., Hillemanns, H. -G., Lichtenegger, W., Zahradnik, H. P., Beyer, J., Schillfart, R., Steiner, H., Duenhoelter, J. H., Göretzlehner, G., Wilken, H., Rudolf, K., Frahm, R., Wiechell, H., Vujić, J., Ciglar, S., Djurić, N., Profeta, K., Mickan, H., Landherr, F., Zander, J., Hölzel, D., Berle, P., Cornely, M., Kühnle, H., Rath, W., Theobald, P., Ulbrich, R., Grande, P., Grande, P., Kühnle, H., Rath, W., Knabe, H., Lehmann, F., Rath, W., Theobald, P., Ulbrich, R., Grande, P., Kühnle, H., Theobald, P., Ulbrich, R., Grande, P., Kühnle, H., Rath, W., Trolp, R., Beyer, J., Schillfahrt, R., Steiner, H., Zahradnik, H. P., von Ritter, St., Rauskolb, R., Spätling, L., Stähler, E., Ulbrich, R., Grande, P., Kühnle, H., Rath, W., Theobald, P., Heinzl, S., Schneider, M., Andor, J., Kunz, J., Bänninger, U., Keller, P. J., Möller, C. -P., Lehmann, F., Briel, R. C., Lippert, Th., Kidess, E., Roemer, V. M., Dennemark, N., Dreher, E., Müller, M., Zahradnik, H. P., Stengele, E., Scherb, L., and Breckwoldt, M.

Published
1979
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31. Influence of aperture diameter on image contrast and resolution in scanning near-field optical microscopy.

Author

Scho¨fer, J., Gregor, M. J., Blome, P. G., and Ulbrich, R. G.

Subjects
NEAR-field microscopy, HOLES, IMAGE processing
Abstract

The influence of aperture diameter on image contrast and resolution in scanning near-field optical microscopy has been investigated. Evanescent standing wave fields at glass-air interfaces were probed with well-characterized aluminum-coated fiber tips. A strong decrease in image contrast was found when the aperture diameter exceeds a critical value. Numerical simulations with the concept of an intensity transfer function using the axial component of the Poynting vector inside the probe demonstrate that this phenomenon is the result of the increasing influence of higher-order waveguide modes on power transmission through the probe. It has been shown that standing wave patterns are convenient and reliable reference devices for individual probe characterization and quantification of their resolving power. [ABSTRACT FROM AUTHOR]

Published
1997
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34. Atomic and electronic structure of the nonpolar GaN (1 1̄ 00) surface

Author

Bertelli, Matteo, Löptien, P., Wenderoth, M., Rizzi, Angela, Ulbrich, R. G., Righi, Maria Clelia, Ferretti, Andrea, Martin Samos, L., Bertoni, Carlo Maria, Catellani, A., Bertelli, Matteo, Löptien, P., Wenderoth, M., Rizzi, Angela, Ulbrich, R. G., Righi, Maria Clelia, Ferretti, Andrea, Martin Samos, L., Bertoni, Carlo Maria, and Catellani, A.

Subjects
Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Electronic, Condensed Matter Physic, Optical and Magnetic Materials
Abstract

We present a cross-section scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS) and ab initio density-functional theory simulations study of the cleaved nonpolar (1 1̄ 00) surface (m -plane) of n -type HVPE GaN free-standing quasisubstrates. Atomically resolved empty and filled states STM topographies show that no reconstruction occurs upon cleavage, as predicted by theory. STS measurements on clean and atomically flat cleaved surfaces (defect concentration σd ≤2× 1012 cm-2) show that the Fermi energy is not pinned and the tunneling current flows through Ga-like electronic states lying outside the fundamental band gap. On surface areas with defect concentration σd 3× 1013 cm-2, the Fermi energy is pinned inside the band gap in defect-derived surface states and tunneling through filled (empty) N-like (Ga-like) states takes place. © 2009 The American Physical Society.

Published
2009

35. Atomic and electronic structure of the cleaved 6H-SiC (11 2̄ 0) surface

Author

BERTELLI, MATTEO, Homoth, J., Wenderoth, M., RIZZI, Angela, Ulbrich, R. G., RIGHI, Maria Clelia, BERTONI, Carlo Maria, Catellani, A., Bertelli, Matteo, Homoth, J., Wenderoth, M., Rizzi, Angela, Ulbrich, R. G., Righi, Maria Clelia, Bertoni, Carlo Maria, and Catellani, A.

Subjects
Condensed Matter::Materials Science, Condensed Matter::Superconductivity, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Condensed Matter Physics
Abstract

We present a combined cross-section scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) and ab initio simulations study of the nonpolar (11 2̄ 0) cleaved surface of 6H-SiC. The experimental results show an unreconstructed surface in agreement with theory. Upon truncation, two surface bands appear inside the semiconductor band gap: one empty band localized on the Si atoms and one filled band on the C atoms. According to the STS experimental results on n -doped samples, the Fermi energy is pinned at the surface inside the band gap. By comparison of STM filled and empty states topographies we propose that on the fresh cleaved surface the Fermi level lies at the bottom of the Si-like band. The calculated STM images reproduce the experimental contrast of the 6H stacking sequence and its bias dependence very well. © 2007 The American Physical Society.

Published
2007

36. Practising change(s): Analysing the German niche of permaculture with a Social Learning perspective to monitor social change in sustainability transitions

Author

Ulbrich, R. (author) and Ulbrich, R. (author)

Abstract

The Master’s programme Industrial Ecology is jointly organised by Leiden University and Delft University of Technology. - Grassroots initiatives that are inspired by the framework of permaculture try to design effective social and ecological systems. These are aimed to provide ecosystem services, build communities, give opportunities to learn and practice and support the establishment of circular nutrient systems. This they do, guided by a dynamic and systemic “manual” that helps to integrate and create many functions and draw on synergistic effects. Many results of such a design are commonly perceived as positive externalities. Drawing on principles and practices that run counter the current way “things are done”, the permaculture community offers potential insights into transformative processes that question the current growth paradigm and mainstream practices. One of the reasons for the growth of the permaculture community lies within its set-up as a community with strong core values and practices. These shared values and practices align members whilst recognising each individual's competences. However, being embedded in an environment that plays according to very different rules, the community also has to deal with tensions at its boundaries. Applying a systems perspective to complex problems allows seeing interwoven dynamics more differentiated. This thesis investigates the potential of combining two analytical lenses to better accommodate the diverse dynamics intrinsic to social systems in sustainability transitions: While Social Learning Systems allow for a close review of dynamics that make up social learning processes, the framework from transition studies stretches the time frame and puts dynamics in the perspective of broader external factors. With the goal to investigate the internal dynamics in a grassroots initiative that shape social learning processes and the potential for such communities to reach out to their environment this thesis establishes a c, Technology, Policy and Management, Industrial Ecology, 4413 TRP 30Y Thesis Research project

Published
2016

37. CARMENES: an overview six months after first light

Author

Quirrenbach, A., additional, Amado, P. J., additional, Caballero, J. A., additional, Mundt, R., additional, Reiners, A., additional, Ribas, I., additional, Seifert, W., additional, Abril, M., additional, Aceituno, J., additional, Alonso-Floriano, F. J., additional, Anwand-Heerwart, H., additional, Azzaro, M., additional, Bauer, F., additional, Barrado, D., additional, Becerril, S., additional, Bejar, V. J. S., additional, Benitez, D., additional, Berdinas, Z. M., additional, Brinkmöller, M., additional, Cardenas, M. C., additional, Casal, E., additional, Claret, A., additional, Colomé, J., additional, Cortes-Contreras, M., additional, Czesla, S., additional, Doellinger, M., additional, Dreizler, S., additional, Feiz, C., additional, Fernandez, M., additional, Ferro, I. M., additional, Fuhrmeister, B., additional, Galadi, D., additional, Gallardo, I., additional, Gálvez-Ortiz, M. C., additional, Garcia-Piquer, A., additional, Garrido, R., additional, Gesa, L., additional, Gómez Galera, V., additional, González Hernández, J. I., additional, Gonzalez Peinado, R., additional, Grözinger, U., additional, Guàrdia, J., additional, Guenther, E. W., additional, de Guindos, E., additional, Hagen, H.-J., additional, Hatzes, A. P., additional, Hauschildt, P. H., additional, Helmling, J., additional, Henning, T., additional, Hermann, D., additional, Hernández Arabi, R., additional, Hernández Castaño, L., additional, Hernández Hernando, F., additional, Herrero, E., additional, Huber, A., additional, Huber, K. F., additional, Huke, P., additional, Jeffers, S. V., additional, de Juan, E., additional, Kaminski, A., additional, Kehr, M., additional, Kim, M., additional, Klein, R., additional, Klüter, J., additional, Kürster, M., additional, Lafarga, M., additional, Lara, L. M., additional, Lamert, A., additional, Laun, W., additional, Launhardt, R., additional, Lemke, U., additional, Lenzen, R., additional, Llamas, M., additional, Lopez del Fresno, M., additional, López-Puertas, M., additional, López-Santiago, J., additional, Lopez Salas, J. F., additional, Magan Madinabeitia, H., additional, Mall, U., additional, Mandel, H., additional, Mancini, L., additional, Marin Molina, J. A., additional, Maroto Fernández, D., additional, Martín, E. L., additional, Martín-Ruiz, S., additional, Marvin, C., additional, Mathar, R. J., additional, Mirabet, E., additional, Montes, D., additional, Morales, J. C., additional, Morales Muñoz, R., additional, Nagel, E., additional, Naranjo, V., additional, Nowak, G., additional, Palle, E., additional, Panduro, J., additional, Passegger, V. M., additional, Pavlov, A., additional, Pedraz, S., additional, Perez, E., additional, Pérez-Medialdea, D., additional, Perger, M., additional, Pluto, M., additional, Ramón, A., additional, Rebolo, R., additional, Redondo, P., additional, Reffert, S., additional, Reinhart, S., additional, Rhode, P., additional, Rix, H.-W., additional, Rodler, F., additional, Rodríguez, E., additional, Rodríguez López, C., additional, Rohloff, R. R., additional, Rosich, A., additional, Sanchez Carrasco, M A., additional, Sanz-Forcada, J., additional, Sarkis, P., additional, Sarmiento, L. F., additional, Schäfer, S., additional, Schiller, J., additional, Schmidt, C., additional, Schmitt, J. H. M. M., additional, Schöfer, P., additional, Schweitzer, A., additional, Shulyak, D., additional, Solano, E., additional, Stahl, O., additional, Storz, C., additional, Tabernero, H. M., additional, Tala, M., additional, Tal-Or, L., additional, Ulbrich, R.-G., additional, Veredas, G., additional, Vico Linares, J. I., additional, Vilardell, F., additional, Wagner, K., additional, Winkler, J., additional, Zapatero Osorio, M.-R., additional, Zechmeister, M., additional, Ammler-von Eiff, M., additional, Anglada-Escudé, G., additional, del Burgo, C., additional, Garcia-Vargas, M. L., additional, Klutsch, A., additional, Lizon, J.-L., additional, Lopez-Morales, M., additional, Ofir, A., additional, Pérez-Calpena, A., additional, Perryman, M. A. C., additional, Sánchez-Blanco, E., additional, Strachan, J. B. P., additional, Stürmer, J., additional, Suárez, J. C., additional, Trifonov, T., additional, Tulloch, S. M., additional, and Xu, W., additional

Published
2016
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41. Therapie der wachstumsretardierung

Author

Moll, W., Grünberger, W., Künzel, W., Petersen, E. E., Schweikhart, G., Kaufmann, P., Stoz, F., Schuhman, R. A., Schröck, R., Junge, H. D., Bauer, K. H., Schuhmann, R., Halberstadt, E., Hertel, K., Quaas, L., Kaltenbach, F. -J., Hillemanns, H. -G., Schuhmann, R., Halberstadt, E., Friedrich, K., Pahnke, V. G., Russewa, R., Kitschke, H. J., Heilmann, L., Siekmann, U., Ludwig, H., Siekmann, U., Heilmann, L., Oggolter-Siekmann, H., Schwenzer, T., Schumann, R., Halberstadt, E., Vetter, K., Fähnrich, J., Keller, P. J., Schneider, H., Roemer, V. M., Bühler, K., Rabe, T., Beth, M., Rüttgers, H., Wille, L., Lorenz, U., Kubli, F., Leucht, W., Rabe, D., Rüttgers, H., Kubli, F., Schneider, H., Baumann, H., Huch, R., Huch, A., Bastert, G., Schuhmann, R., Halberstadt, E., Wolff, F., Fischer, J. H., Bolte, A., Husstedt, W., Erbersdobler, H., Schneider, H., Sodha, R. J., Young, M., Spätling, L., Huch, R., Huch, A., Klöpper, A., Goecke, C., Meinen, K., Breinl, H., Stofft, E., Spätling, L., Fallenstein, F., Schneider, H., Huch, A., Huch, R., Hiltmann, W. -D., Wiest, W., Wiest, W., Hiltmann, W. D., Hettenbach, A., Kachel, W., Pohl, R., Spelger, B., Delucca, A., Moroder, W., Welponer, F., Berić, B., Kranz, F., Marjanović, M., Rath, W., König, A., Hilgers, R., Ulbrich, R., Kuske, R., Kühnle, H., Kuhn, W., Husslein, P., Kofler, E., Rasmussen, A., Fuchs, F., and Fuchs, A. R.

Published
1983
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43. Allgemeines

Author

Brachetti, A. K. J., Emmrich, J., Limburg, H., Albrecht, M., Trams, G., Lehmann, F., Schulz, K. -D., Schmidt-Rhode, P., Weymar, P., Geiger, W., Künzig, H. J., Schleich, A., Wiest, W., Grumbrecht, C., Stosiek, U., Nord, D., Bastert, G., Michel, R. T., Fortmeyer, H. P., Schmidt-Matthiesen, H., Teufel, G., Ritter, R., Pfleiderer, A., Bastert, G., Schmidt-Matthiesen, G., Theobald, P., Pfau, P., Rahlf, G., Keller, E., Schmelzle, R., Maier, W., Schindler, A. E., Schrage, R., Schmid, H., Ulbrich, R., Rath, W., Limburg, H., Brachetti, A. K. J., Riede, U. N., Weymar, P., Schulz, K. D., Noldus, B., Schmidt-Rhode, P., Kaltenbach, F. J., Fettig, O., Kapp-Schwoerer, H., Ladner, H. -A., Hillemanns, H. -G., v. Fournier, D., Kubli, F., Bauer, M., Schneider-Affeld, F., Kaufmann, M., Sander, H., Wigand, K., Schulze, S., Keçecicoğlu, Y., Abts, H., Semm, K., Drähne, A., Kaufmann, I., and Kunz, S.

Published
1979
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44. Electronic disorder of P- and B-doped Si at the metal-insulator transition investigated by scanning tunnelling microscopy and electronic transport

Author

Sürgers, C., Wenderoth, M., Löser, K., Garleff, J. K., Ulbrich, R. G., Lukas, M., and Löhneysen, Hilbert Von

Subjects
Physics, scanning tunnelling microscopy, Electronic disorder, ddc:530
Abstract

he (111)-2 × 1 surface of in situ cleaved heavily P- or B-doped Si is investigated by scanning tunnelling microscopy and spectroscopy at room temperature and at low temperature. P atoms have been identified on different sites of the Si(111)-2 × 1 surface by their characteristic voltage-dependent contrast for positive as well as negative buckling of the π-bonded chains. The distributions of dopants per surface area and of nearest-neighbour distances are found to be in agreement with a random arrangement of dopants in Si up to doping levels well above the metal–insulator transition. In addition, P atoms have been identified by their depth-dependent contrast down to the third layer beneath the surface with a volume density in agreement with the bulk doping density. The random electronic disorder supports the view of an Anderson transition driven by disorder close to the critical concentration or critical uniaxial stress. peerReviewed

Published
2013

46. Analysis of Biomass ORC Plant Connected to a District Heating Network

Author

Strzalka, R., Ulbrich, R., and Eicker, U.

Subjects
Biomass
Abstract

Today, biomass is most efficiently used in decentralized cogeneration plants. Through the use of the ORC (Organic Rankine Cycle) technology, power plants below 10 MWth thermal output can be operated at lower temperature and pressure than conventional steam plants, thus requiring less operation and maintenance effort. Due to high efficiency of part load operation such plants are an interesting alternative for municipal and commercial heat supply. However, the technology is rather new and practical experience is required to access the real performance and operational reliability.The energy supply system of the urban area Scharnhauser Park is a practical example for the utilization of the ORC technology. An urban quarter with a living space of 130000 m2 and 48000 m2 office space is heated by a cogeneration plant connected to a district heating network with a length of 13.5 km. The plant is fired mainly by park waste wood and forest residues are burned additionally. The cogeneration system is equipped with a 6.3 MWth biomass furnace and covers the main part of the heat demands of the quarter. The installation has a pilot project character and can be used for investigations of wood-fired cogeneration systems.The paper contains a review about the practical experience and investigation results that have been gathered since begin of the plant operation. A wood chip boiler with a cogeneration module, connected to a district heating network is being completely monitored from the fuel delivery to heat distribution. More than 60 process parameters have been continuously archived by a data acquisition system. The analysis aims to estimate the efficiency and the ecological parameters of the combination of the ORC module and biomass furnace by consideration of the requirements of a district heating network., Proceedings of the 18th European Biomass Conference and Exhibition, 3-7 May 2010, Lyon, France, pp. 1347-1351

Published
2010
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47. Atomic and electronic structure of the nonpolar GaN(11-00) surface

Author

Bertelli M. a, Loeptien P. a, Wenderoth M a., Rizzi A. a, Ulbrich R. a, Righi M.C. b, Ferretti A. b, Martin-Samos L. b, Bertoni C. b, and Catellani A. c

Subjects
ab initio calculations, Atomic structure, Nitrides
Abstract

We present a cross-section scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS) and ab initio density-functional theory simulations study of the cleaved nonpolar (1100) surface (m-plane) of n-type HVPE GaN free-standing quasisubstrates. Atomically resolved empty and filled states STM topographies show that no reconstruction occurs upon cleavage, as predicted by theory. STS measurements on clean and atomically flat cleaved surfaces (defect concentration sigmad=3×1013 cm−2, the Fermi energy is pinned inside the band gap in defect-derived surface states and tunneling through filled (empty) N-like (Ga-like) states takes place.

Published
2009
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