Institution
Aalto University
Education•Espoo, Finland•
About: Aalto University is a education organization based out in Espoo, Finland. It is known for research contribution in the topics: Computer science & Context (language use). The organization has 9969 authors who have published 32648 publications receiving 829626 citations. The organization is also known as: TKK & Aalto-korkeakoulu.
Papers published on a yearly basis
Papers
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TL;DR: Different preparation methods for lignin-based nanomaterials with antioxidant UV-absorbing and antimicrobial properties that can be used as reinforcing agents in nanocomposites, in drug delivery and gene delivery vehicles for biomedical applications are described.
456 citations
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TL;DR: In this article, the authors propose an alternative definition of R2 for Bayesian fits, where the numerator can be larger than the denominator, which is a problem for Bayes fits.
Abstract: The usual definition of R2 (variance of the predicted values divided by the variance of the data) has a problem for Bayesian fits, as the numerator can be larger than the denominator. We propose an...
452 citations
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TL;DR: In this article, a general approach to the synthesis of metasurfaces for full control of transmitted and reflected plane waves and show that perfect performance can be realized based on the use of an equivalent impedance matrix model.
Abstract: Nonuniform metasurfaces (electrically thin composite layers) can be used for shaping refracted and reflected electromagnetic waves. However, known design approaches based on the generalized refraction and reflection laws do not allow realization of perfectly performing devices: there are always some parasitic reflections into undesired directions. In this paper we introduce and discuss a general approach to the synthesis of metasurfaces for full control of transmitted and reflected plane waves and show that perfect performance can be realized. The method is based on the use of an equivalent impedance matrix model which connects the tangential field components at the two sides on the metasurface. With this approach we are able to understand what physical properties of the metasurface are needed in order to perfectly realize the desired response. Furthermore, we determine the required polarizabilities of the metasurface unit cells and discuss suitable cell structures. It appears that only spatially dispersive metasurfaces allow realization of perfect refraction and reflection of incident plane waves into arbitrary directions. In particular, ideal refraction is possible only if the metasurface is bianisotropic (weak spatial dispersion), and ideal reflection without polarization transformation requires spatial dispersion with a specific, strongly nonlocal response to the fields.
450 citations
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TL;DR: In this paper, the existence of entanglement in the steady state of two massive micromechanical oscillators coupled to a microwave-frequency electromagnetic cavity was shown to be established by combining measurements of correlated mechanical fluctuations with analysis of the microwaves emitted from the cavity.
Abstract: Quantum entanglement is a phenomenon whereby systems cannot be described independently of each other, even though they may be separated by an arbitrarily large distance
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. Entanglement has a solid theoretical and experimental foundation and is the key resource behind many emerging quantum technologies, including quantum computation, cryptography and metrology. Entanglement has been demonstrated for microscopic-scale systems, such as those involving photons2–5, ions
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and electron spins
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, and more recently in microwave and electromechanical devices8–10. For macroscopic-scale objects8–14, however, it is very vulnerable to environmental disturbances, and the creation and verification of entanglement of the centre-of-mass motion of macroscopic-scale objects remains an outstanding goal. Here we report such an experimental demonstration, with the moving bodies being two massive micromechanical oscillators, each composed of about 10
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atoms, coupled to a microwave-frequency electromagnetic cavity that is used to create and stabilize the entanglement of their centre-of-mass motion15–17. We infer the existence of entanglement in the steady state by combining measurements of correlated mechanical fluctuations with an analysis of the microwaves emitted from the cavity. Our work qualitatively extends the range of entangled physical systems and has implications for quantum information processing, precision measurements and tests of the limits of quantum mechanics.
450 citations
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TL;DR: In this paper, the authors investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data and find that the universe is ionized at less than the 10% level at redshifts above z ≃ 10.8.
Abstract: We investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy data in temperature with the low-multipole polarization data to fit ΛCDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth τ = 0.058 ± 0.012 for the commonly adopted instantaneous reionization model. This confirms, with data solely from CMB anisotropies, the low value suggested by combining Planck 2015 results with other data sets, and also reduces the uncertainties. We reconstruct the history of the ionization fraction using either a symmetric or an asymmetric model for the transition between the neutral and ionized phases. To determine better constraints on the duration of the reionization process, we also make use of measurements of the amplitude of the kinetic Sunyaev-Zeldovich (kSZ) effect using additional information from the high-resolution Atacama Cosmology Telescope and South Pole Telescope experiments. The average redshift at which reionization occurs is found to lie between z = 7.8 and 8.8, depending on the model of reionization adopted. Using kSZ constraints and a redshift-symmetric reionization model, we find an upper limit to the width of the reionization period of Δz < 2.8. In all cases, we find that the Universe is ionized at less than the 10% level at redshifts above z ≃ 10. This suggests that an early onset of reionization is strongly disfavoured by the Planck data. We show that this result also reduces the tension between CMB-based analyses and constraints from other astrophysical sources.
449 citations
Authors
Showing all 10135 results
Name | H-index | Papers | Citations |
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John B. Goodenough | 151 | 1064 | 113741 |
Ashok Kumar | 151 | 5654 | 164086 |
Anne Lähteenmäki | 116 | 485 | 81977 |
Kalyanmoy Deb | 112 | 713 | 122802 |
Riitta Hari | 111 | 491 | 43873 |
Robin I. M. Dunbar | 111 | 586 | 47498 |
Andreas Richter | 110 | 769 | 48262 |
Mika Sillanpää | 96 | 1019 | 44260 |
Muhammad Farooq | 92 | 1341 | 37533 |
Ivo Babuška | 90 | 376 | 41465 |
Merja Penttilä | 87 | 303 | 22351 |
Andries Meijerink | 87 | 426 | 29335 |
T. Poutanen | 86 | 120 | 33158 |
Sajal K. Das | 85 | 1124 | 29785 |
Kalle Lyytinen | 84 | 426 | 27708 |