MTP: A Movie Transmission Protocol for Multimedia Applications

Typical color video adapters of today's PCs and workstationsuse 8 bits per pixel as an index into the color lookup table (CLUT). Full color pictures and movies have to be reduced to 256 colors. In order to avoid false colors between two frames of a digital movie, a novel technique for computing the CLUT's is proposed: A subset of the CLUT entries is reserved for new colors of the next frame. The paper presents an algorithm for the gradual adaption of the color lookup table during the transmission of a movie. First experience is reported in the framework of the XMovie project

Fabry-Perot enhanced Faraday rotation in graphene

We demonstrate that giant Faraday rotation in graphene in the terahertz range due to the cyclotron resonance is further increased by constructive Fabry-Perot interference in the supporting substrate. Simultaneously, an enhanced total transmission is achieved, making this effect doubly advantageous for graphene-based magneto-optical applications. As an example, we present far-infrared spectra of epitaxial multilayer graphene grown on the C-face of 6H-SiC, where the interference fringes are spectrally resolved and a Faraday rotation up to 0.15 radians (9{\deg}) is attained. Further, we discuss and compare other ways to increase the Faraday rotation using the principle of an optical cavity

The conduction pathway of potassium channels is water free under physiological conditions.

Ion conduction through potassium channels is a fundamental process of life. On the basis of crystallographic data, it was originally proposed that potassium ions and water molecules are transported through the selectivity filter in an alternating arrangement, suggesting a "water-mediated" knock-on mechanism. Later on, this view was challenged by results from molecular dynamics simulations that revealed a "direct" knock-on mechanism where ions are in direct contact. Using solid-state nuclear magnetic resonance techniques tailored to characterize the interaction between water molecules and the ion channel, we show here that the selectivity filter of a potassium channel is free of water under physiological conditions. Our results are fully consistent with the direct knock-on mechanism of ion conduction but contradict the previously proposed water-mediated knock-on mechanism

Perfect alignment and preferential orientation of nitrogen-vacancy centers during CVD growth of diamond on (111) surfaces

Synthetic diamond production is key to the development of quantum metrology and quantum information applications of diamond. The major quantum sensor and qubit candidate in diamond is the nitrogen-vacancy (NV) color center. This lattice defect comes in four different crystallographic orientations leading to an intrinsic inhomogeneity among NV centers that is undesirable in some applications. Here, we report a microwave plasma-assisted chemical vapor decomposition (MPCVD) diamond growth technique on (111)-oriented substrates that yields perfect alignment ($94\pm2$) of as-grown NV centers along a single crystallographic direction. In addition, clear evidence is found that the majority ($74\pm4$) of the aligned NV centers were formed by the nitrogen being first included in the (111) growth surface and then followed by the formation of a neighboring vacancy on top. The achieved homogeneity of the grown NV centers will tremendously benefit quantum information and metrology applications.Comment: 6 pages, 4 figures, changes to previous version: added acknowledgemen

Multiscale investigations in a mesoscale catchment ? hydrological modelling in the Gera catchment

International audienceThe application of the hydrological process-oriented model J2000 (J2K) is part of a cooperation project between the Thuringian Environmental Agency (Thüringer Landesanstalt für Umwelt und Geologie ? TLUG) and the Department of Geoinformatics of the Friedrich-Schiller-University Jena focussing on the implementation of the EU water framework directive (WFD). In the first project phase J2K was parametrised and calibrated for a mesoscale catchment to quantify if it can be used as hydrological part of a multi-objective tool-box needed for the implementation of the WFD. The main objectives for that pilot study were: The development and application of a suitable distribution concept which provide the spatial data basis for various tasks and which reflects the specific physiogeographical variability and heterogeneity of river basins adequately. This distribution concept should consider the following constraints: The absolute number of spatial entities, which forms the basis for any distributive modelling should be as small as possible, but the spatial distributed factors, which controls quantitative and qualitative hydrological processes should not be generalised to much. The distribution concept of hydrological response units HRUs (Flügel, 1995) was selected and enhanced by a topological routing scheme (Staudenrausch, 2001) for the simulation of lateral flow processes. J2K should be calibrated for one subbasin of the pilot watershed only. Then the parameter set should be used on the other subbasins (referred as transfer basins) to investigate and quantify the transferability of a calibrated model and potential spatial dependencies of its parameter set. In addition, potential structural problems in the process description should be identified by the transfer to basins which show a different process dominance as the one which was used for calibration does. Model calibration and selection of efficiency criteria for the quantification of the model quality should be based on a comprehensive sensitivity and uncertainty analysis (Bäse, 2005) and multi-response validations with independent data sets (Krause and Flügel, 2005) carried out in advance in the headwater part of the calibration basin. To obtain good results in the transfer basins the calibrated parameter set could be adjusted slightly. This step was considered as necessary because of specific constraints which were not of significant importance in the calibration basin. This readjustment should be carried out on parameters which show a sensitive reaction on the identified differences in the environmental setup. Potential scaling problems of the process description, distribution concept or model structure should be identified by the comparison of the modelling results obtained in a small headwater region of the calibration basin with observed streamflow to find out if the selected efficiency measures show a significant change

Precipitated iron: a limit on gettering efficacy in multicrystalline silicon

A phosphorus diffusion gettering model is used to examine the efficacy of a standard gettering process on interstitial and precipitated iron in multicrystalline silicon. The model predicts a large concentration of precipitated iron remaining after standard gettering for most as-grown iron distributions. Although changes in the precipitated iron distribution are predicted to be small, the simulated post-processing interstitial iron concentration is predicted to depend strongly on the as-grown distribution of precipitates, indicating that precipitates must be considered as internal sources of contamination during processing. To inform and validate the model, the iron distributions before and after a standard phosphorus diffusion step are studied in samples from the bottom, middle, and top of an intentionally Fe-contaminated laboratory ingot. A census of iron-silicide precipitates taken by synchrotron-based X-ray fluorescence microscopy confirms the presence of a high density of iron-silicide precipitates both before and after phosphorus diffusion. A comparable precipitated iron distribution was measured in a sister wafer after hydrogenation during a firing step. The similar distributions of precipitated iron seen after each step in the solar cell process confirm that the effect of standard gettering on precipitated iron is strongly limited as predicted by simulation. Good agreement between the experimental and simulated data supports the hypothesis that gettering kinetics is governed by not only the total iron concentration but also by the distribution of precipitated iron. Finally, future directions based on the modeling are suggested for the improvement of effective minority carrier lifetime in multicrystalline silicon solar cells

Full-Wafer Roller-NIL Processes for Silicon Solar Cell Texturisation

The highest solar cell efficiencies both for c-Si and mc-Si were reached using template based texturing processes. Especially for mc-Si the benefit of a defined texture, the so called honeycomb texture, was demonstrated impressively. However, up until now, no industrially feasible process has been available to pattern the necessary etching masks with the sufficient resolution. Roller-Nanoimprint Lithography (Roller-NIL) has the potential to overcome these limitations and to allow high quality pattern transfers, even in the sub-micron regime, in continuous in-line processes. Therefore, this etch-mask patterning technique is a suitable solution to bring such elaborate features like the honeycomb texture to an industrial realization. Beyond that, this fast printing-like technology opens up new possibilities to introduce promising concepts like photonic structures into solar cells