Search results for "SHIFT"
showing 10 items of 1226 documents
Super-orthogonal space-time trellis codes with differential phase modulation for noncoherent mobile communication systems
2010
In this paper, we show how to design super-orthogonal space-time trellis codes (SOSTTCs) using the differential binary phase-shift keying (PSK) modulation for noncoherent communication systems, for which the knowledge of the channel state information (CSI) at the receiver is not necessary. Moreover, a new decoding algorithm with reduced decoding complexity is proposed. In all simulations, a geometric two-ring channel model is employed to evaluate the performance of the SOSTTCs. The simulation results show that the proposed decoding algorithm has the same decoding performance compared with the traditional decoding strategy, while the new algorithm reduces significantly the overall computing …
Oligo(phenylenevinylene)s with reactive side chains: amine- and amide-bound alkoxysilanes
2002
Strongly luminescent oligo(phenylenevinylene) chromophores with monodisperse chain lengths are connected via short spacers containing a secondary amine or amide with di- and tri-ethoxysilane groups. The alkoxysilanes can be hydrolysed and condensed to cyclic and linear oligomers with high film forming capability and are also interesting functional units for hybrid materials for electro-optical applications. The luminescence properties in the solid state are influenced by hydrogen bonding of the amides resulting in strong hypsochromic shifts. The synthesis of the title compounds, their oligomerisation and the electronic spectra in the solution and solid state are presented.
Lamb shift of a uniformly accelerated hydrogen atom in the presence of a conducting plate
2009
We investigate the effects of acceleration on the energy-level shifts of a hydrogen atom interacting with the electromagnetic field and in the presence of an infinite perfectly conducting plate. We consider the contributions of vacuum fluctuations and of the radiation reaction field to the Lamb shift, and we discuss their dependence from the acceleration of the atom. We show that, because of the presence of the boundary, both vacuum field fluctuations and radiation reaction field contributions are affected by atomic acceleration. In particular, the effect of the vacuum field fluctuations on the energy-level shifts is not equivalent to that of a thermal field. We also discuss the dependence …
Luminescence of a self-trapped exciton in GeO2 crystal
1993
Abstract The self-trapped exciton (STE) is discovered in the GeO2 crystal. A PL band at 2.5 eV with a strong Stokes shift is excited only in the fundamental absorption range of GeO2 crystal with the quantum yield about 0.4 and the decay time constant 800 ± 5 μs at 80 K. The PL thermal quenching occurs at 200 K with the energy about 0.25 eV and the frequency factor 107. At 4.5 K the PL decay kinetics splits into two components with time constants 270 μs and 8000 μs, which can be due to a triplet state split in the zero magnetic field. The STE in GeO2 is very similar to a STE in SiO2.
The impact of space development structure on the level of ecological footprint - Shift share analysis for European Union countries
2022
The impact of the space development structure on the level of the ecological footprint is an important element of the sustainable development policy, determining not only its directions, but also indicating the manner of respecting en- vironmental principles. The aim of the research is to assess the impact of the spatial development structure on the eco- logical footprint level. The considerations are based on the assumption that the spatial development structure is a determinant of the ecological footprint level. The study used the shift share analysis method. Selected European coun- tries were the subject of the research. The research period covered the years 2009–2019. The spatial differ…
Depletion of coastal predatory fish sub-stocks coincided with the largest sea urchin grazing event observed in the NE Atlantic
2020
AbstractIn this contribution, we propose fishery driven predator release as the cause for the largest grazing event ever observed in the NE Atlantic. Based on the evolving appreciation of limits to population connectivity, published and previously unpublished data, we discuss whether overfishing caused a grazer bloom of the sea urchin (Strongylocentrotus droebachiensis) resulting in overgrazing of more than 2000 km2 kelp (Laminaria hyperborea) forest along Norwegian and Russian coasts during the 1970 s. We show that coastal fisheries likely depleted predatory coastal fish stocks through modernization of fishing methods and fleet. These fish were important predators on urchins and the reduct…
A Holistic Approach to Comprehending the Complexity of the Post-growth Era: The Emerging Profile
2015
The goal of this study is to investigate the problems caused by the rapid growth of the global economy, coupled with high population growth and the excessive exploitation of natural resources. The global economy will not be able to maintain its current speed of growth in the long term, so a paradigm shift in production and consumption is necessary, if the collapse of ecosystems and the concurrent depletion of natural resources are to be avoided. This is the reason why capitalism needs to take a turn towards a sustainable and naturally harmonized development model.
Experimental generation of optical flaticon pulses
2013
International audience; We experimentally investigate the nonlinear reshaping of a continuous wave which leads to chirp-free and flat-top intense pulses or flaticons exhibiting strong temporal oscillations at their edges and a stable self-similar expansion upon propagation of their central region. This study was performed in the normal dispersion regime of a non-zero dispersion-shifted fiber and involved a sinusoidal phase modulation of the continuous wave. Our fiber optics experiment is analogous to considering the collision between oppositely directed currents near the beach, and it may open the way to new investigations in the field of hydrodynamics.
Learning from Social Collaboration
2017
This chapter focuses on the challenge of evaluating game-based learning. It argues that linking game-based learning with the characteristics of a specific game or game-produced engagement is challenging. It further proposes a framework in which the game-based learning process is approached by considering (business) simulation games as Computer-Supported Collaborative Learning (CSCL) environments and presents an approach on how learning can be approached and evaluated from this perspective. In addition, it highlights how simulation game mechanics appears to be a potential way to promote learners' socio-emotional processes and give rise to social interaction and to structure collaboration amo…
Organoplatinum(II) Complexes Self-Assemble and Recognize AT-Rich Duplex DNA Sequences
2021
The specific recognition of AT-rich DNA sequences opens up the door to promising diagnostic and/or therapeutic strategies against gene-related diseases. Here, we demonstrate that amphiphilic PtII complexes of the type [Pt(dmba)(N∧N)]NO3 (dmba = N,N-dimethylbenzylamine-κN, κC; N∧N = dpq (3), dppz (4), and dppn (5)) recognize AT-rich oligonucleotides over other types of DNA, RNA, and model proteins. The crystal structure of 4 shows the presence of significant π-stacking interactions and a distorted coordination sphere of the d8 PtII atom. Complex 5, containing the largest π-conjugated ligand, forms supramolecular assemblies at high concentrations under aqueous environment. However, its aggreg…