The Royal Institute of Technology is a university in Stockholm, Sweden. KTH was founded in 1827 as Sweden's first polytechnic and is one of Scandinavia's largest institutions of higher education in technology. KTH accounts for one-third of Sweden's technical research and engineering education capacity at university level. KTH offers programmes leading to a Master of Architecture, Master of Science in Engineering, Bachelor of Science in Engineering, Bachelor of Science, Master of Science, licentiate or doctoral degree. The university also offers a technical preparatory programme for non-scientists and further education.There are a total of just over 14 000 full-year equivalent undergraduate students, more than 1700 active postgraduate students and 4600 full-time-equivalent employees. KTH is one of the leading technical universities in Europe and highly respected worldwide, especially in the domains of technology and natural science. Wikipedia.
Wiklund M.,KTH Royal Institute of Technology
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2012
Manipulation of biological cells by acoustic radiation forces is often motivated by its improved biocompatibility relative to alternative available methods. On the other hand, it is well known that acoustic exposure is capable of causing damage to tissue or cells, primarily due to heating or cavitation effects. Therefore, it is important to define safety guidelines for the design and operation of the utilized devices. This tutorial discusses the biocompatibility of devices designed for acoustic manipulation of mammalian cells, and different methods for quantifying the cell viability in such devices. © 2012 The Royal Society of Chemistry.
Gouteraux B.,KTH Royal Institute of Technology
Journal of High Energy Physics | Year: 2014
In this work, we examine how charge is transported in a theory where momentum is relaxed by spatially dependent, massless scalars. We analyze the possible IR phases in terms of various scaling exponents and the (ir)relevance of operators in the IR effective holographic theory with a dilaton. We compute the (finite) resistivity and encounter broad families of (in)coherent metals and insulators, characterized by universal scaling behaviour. The optical conductivity at zero temperature and low frequencies exhibits power tails which can violate scaling symmetries, due to the running of the dilaton. At low temperatures, our model captures features of random-field disorder. © The Authors.
Lourdudoss S.,KTH Royal Institute of Technology
Current Opinion in Solid State and Materials Science | Year: 2012
This article reviews the major achievements in recent years on heteroepitaxy and selective area heteroepitaxy that are relevant to silicon photonics. Material aspects are given due importance without trying to cover all kinds of devices. Under heteroepitaxy several systems based on GaAs, InP and GaSb and their related materials and dilute III-nitrides all on Si substrates are covered and assessed. Quantum dot and quantum well lasers are taken as device examples. The potential of the emerging SnGeSi/Si system is highlighted. Under selective area heteroepitaxy, growth of InP from SiO 2 trenches in Si and epitaxial lateral overgrowth of InP on silicon are exemplified as the potential routes for monolithic integration on silicon. The expected trends and anticipated advances are indicated. © 2012 Elsevier Ltd. All rights reserved.
Miao G.,KTH Royal Institute of Technology
IEEE Transactions on Wireless Communications | Year: 2013
This paper addresses optimal energy-efficient design for uplink (UL) MU-MIMO in a single cell environment. The energy efficiency is measured by throughput per Joule, while both RF transmission power and device electronic circuit power are considered. We define the energy efficiency (EE) capacity for UL MU-MIMO and study the power allocation that achieves this capacity. First we assume all users consume a fixed amount of circuit power and show that user antennas should be used only when the corresponding spatial channels are sufficiently good and using them improves the overall network EE. Mobile devices may have improved circuit management capability and turn off circuit operations when some antennas are not used to reduce circuit power consumption. Therefore we further study energy-efficient UL MU-MIMO with improved circuit management and show that some antennas should not be used even when their channel states are good because turning them on consumes too much circuit power. Based on theoretical analysis, we further develop low-complexity yet globally optimal energy-efficient power allocation algorithms that converge to the optimum exponentially. Simulation results are provided to demonstrate the significant gain in network energy efficiency. © 2002-2012 IEEE.
Briat C.,KTH Royal Institute of Technology
IEEE Transactions on Automatic Control | Year: 2011
The Jensen's inequality plays a crucial role in the analysis of time-delay and sampled-data systems. Its conservatism is studied through the use of the Grüss Inequality. It has been reported in the literature that fragmentation (or partitioning) schemes allow to empirically improve the results. We prove here that the Jensen's gap can be made arbitrarily small provided that the order of uniform fragmentation is chosen sufficiently large. Nonuniform fragmentation schemes are also shown to speed up the convergence in certain cases. Finally, a family of bounds is characterized and a comparison with other bounds of the literature is provided. It is shown that the other bounds are equivalent to Jensen's and that they exhibit interesting well-posedness and linearity properties which can be exploited to obtain better numerical results. © 2011 IEEE.
Moberg C.,KTH Royal Institute of Technology
Angewandte Chemie - International Edition | Year: 2013
Two views: The mechanism of the conjugate addition of linear aldehydes to nitro olefins has been investigated by two research groups. In spite of extensive experimental data, important questions remain unanswered (see scheme; TMS=trimethylsilyl, En=enamine). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Walter M.V.,KTH Royal Institute of Technology |
Malkoch M.,KTH Royal Institute of Technology
Chemical Society Reviews | Year: 2012
Dendrimers are highly branched and monodisperse macromolecules that display an exact and large number of functional groups distributed with unprecedented control on the dendritic framework. Based on their globular structure, compared to linear polymers of the same molecular weight, dendrimers are foreseen to deliver extraordinary features for applications in areas such as cancer therapy, biosensors for diagnostics and light harvesting scaffolds. Of the large number of reports on dendrimer synthesis only a few have reached commercial availability. This limitation can be traced back to challenges in the synthetic paths including a large number of reaction steps required to obtain dendritic structures with desired features. Along with an increased number of reaction steps come not only increased waste of chemical and valuable starting materials but also an increased probability to introduce structural defects in the dendritic framework. This tutorial review briefly covers traditional growth approaches to dendrimers and mainly highlights accelerated approaches to dendrimers. A special focus capitalizes on the impact of the click chemistry concept on dendrimer synthesis and the promise it has to successfully accomplish highly sophisticated dendrimers, both traditional as well as heterofunctional, in a minimum number of chemical steps. It is clear that accelerated synthetic approaches are of greatest importance as these will encourage the scientific community to synthesize and access dendrimers for specific applications. The final goal of accelerated synthesis is to deliver economically justified dendritic materials for future applications without compromising the environmental perspective. © 2012 The Royal Society of Chemistry.
Aronson M.F.,KTH Royal Institute of Technology
Proceedings. Biological sciences / The Royal Society | Year: 2014
Urbanization contributes to the loss of the world's biodiversity and the homogenization of its biota. However, comparative studies of urban biodiversity leading to robust generalities of the status and drivers of biodiversity in cities at the global scale are lacking. Here, we compiled the largest global dataset to date of two diverse taxa in cities: birds (54 cities) and plants (110 cities). We found that the majority of urban bird and plant species are native in the world's cities. Few plants and birds are cosmopolitan, the most common being Columba livia and Poa annua. The density of bird and plant species (the number of species per km(2)) has declined substantially: only 8% of native bird and 25% of native plant species are currently present compared with estimates of non-urban density of species. The current density of species in cities and the loss in density of species was best explained by anthropogenic features (landcover, city age) rather than by non-anthropogenic factors (geography, climate, topography). As urbanization continues to expand, efforts directed towards the conservation of intact vegetation within urban landscapes could support higher concentrations of both bird and plant species. Despite declines in the density of species, cities still retain endemic native species, thus providing opportunities for regional and global biodiversity conservation, restoration and education.
Moberg C.,KTH Royal Institute of Technology
Angewandte Chemie - International Edition | Year: 2011
Same difference: Berry pseutorotation (BPR) and Ugi turnstile rotation, which are generally treated as two distinctly different mechanisms for rearrangement of trigonal-bipyramidal structures, have been shown to be equivalent. Alternative mechanisms consist of sequences of pseudorotations proceeding in a single step. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Agren J.,KTH Royal Institute of Technology
Scripta Materialia | Year: 2014
The "materials genome" was given a rather vague definition in US President Obama's announcement in 2011. We argue that the materials genome, analogously with biological genomes, should be defined as a set of information (databases) allowing prediction of a material's structure, as well as its response to processing and usage conditions. The materials genome is thus encoded in the language of CALPHAD thermodynamics and kinetics, as such databases are major parts of integrated computational materials engineering. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.