Institution
Helsinki University of Technology
About: Helsinki University of Technology is a based out in . It is known for research contribution in the topics: Thin film & Vortex. The organization has 8962 authors who have published 20136 publications receiving 723787 citations. The organization is also known as: TKK & Teknillinen korkeakoulu.
Papers published on a yearly basis
Papers
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TL;DR: In this article, the performance of the noble metal catalysts, especially the Rh-containing catalysts was similar or better than that of the conventional sulfided CoMo/Al2O3 catalyst.
488 citations
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TL;DR: In this article, the research and application of airborne laser scanning for forest inventory in Finland, Norway and Sweden is reviewed. But the main objective has been to develop methods that are directly suited for practical forest inventory at the stand level.
Abstract: This article reviews the research and application of airborne laser scanning for forest inventory in Finland, Norway and Sweden. The first experiments with scanning lasers for forest inventory were conducted in 1991 using the FLASH system, a full-waveform experimental laser developed by the Swedish Defence Research Institute. In Finland at the same time, the HUTSCAT profiling radar provided experiences that inspired the following laser scanning research. Since 1995, data from commercially operated time-of-flight scanning lasers (e.g. TopEye, Optech ALTM and TopoSys) have been used. Especially in Norway, the main objective has been to develop methods that are directly suited for practical forest inventory at the stand level. Mean tree height, stand volume and basal area have been the most important forest mensurational parameters of interest. Laser data have been related to field training plot measurements using regression techniques, and these relationships have been used to predict corresponding properti...
486 citations
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TL;DR: It is suggested that the initiation and maintenance of stimulus-locked hippocampal theta observed here may facilitate processing of potentially salient and/or novel input with respect to a context established by the contents of WM.
Abstract: Working memory (WM) is the ability to retain and associate information over brief time intervals. Functional imaging studies demonstrate that WM is mediated by a distributed network including frontal and posterior cortices, hippocampus, and cerebellum. In rodents, the presentation of stimuli in a WM task is followed by a reset of the phase of hippocampal theta. In this paper we report the observation of a similar phenomenon in normal human subjects. Neuromagnetic responses were recorded during presentation of a set of digits and a subsequent probe of the retained items. All stimuli were presented with a fixed temporal pattern. We observed phase reset of ≈7 Hz theta in left hippocampus ≈120 ms after probe stimuli, whereas reset of theta in right hippocampus was visible ≈80 ms prior to these anticipated stimuli. The duration of stimulus-locked theta increased with memory load, with a limiting value of ≈600 ms for 5–7 retained items. We suggest that, as in rats, stimulus-locked theta may index involvement of human hippocampal networks in the cognitive processing of sensory input. The anticipatory phase reset of theta indicates involvement of hippocampus in right hemisphere and cerebellar timing networks. Hippocampal structures are essential for orientation to perturbations in the sensory scene, a function that requires use of a context established by a constellation of stimuli. We suggest that the initiation and maintenance of stimulus-locked hippocampal theta observed here may facilitate processing of potentially salient and/or novel input with respect to a context established by the contents of WM.
486 citations
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TL;DR: In this paper, a new electric equivalent circuit for the forces created by a squeezed gas film between vertically moving planar surfaces is presented. Butler et al. used the circuit model to calculate the effective viscosity in a narrow gap between the moving surfaces.
Abstract: We present a new electric equivalent circuit for the forces created by a squeezed gas film between vertically moving planar surfaces. The model is realized with frequency-dependent resistors and inductors. Circuit analysis tools are applied to calculate the response of a micromechanical silicon capacitive accelerometer in both the frequency and the time domains. The simulations are shown to match the measured frequency responses in an excellent way. We utilize the circuit model to calculate the effective viscosity in a narrow gap between the moving surfaces. The results are compared with different slip-flow equations discussed in the literature. We present a simple approximate equation of the pressure-dependent viscosity that is valid for both viscous and molecular damping regions, and has 5% accuracy.
483 citations
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TL;DR: A detailed study of the energetics of periodic graphene antidot lattices is presented, the level structure of a single defect is analyzed, the exchange coupling between a pair of spin qubits is calculated, and possible avenues for further developments are identified.
Abstract: Antidot lattices, defined on a two-dimensional electron gas at a semiconductor heterostructure, are a well-studied class of man-made structures with intriguing physical properties. We point out that a closely related system, graphene sheets with regularly spaced holes ("antidots"), should display similar phenomenology, but within a much more favorable energy scale, a consequence of the Dirac fermion nature of the states around the Fermi level. Further, by leaving out some of the holes one can create defect states, or pairs of coupled defect states, which can function as hosts for electron spin qubits. We present a detailed study of the energetics of periodic graphene antidot lattices, analyze the level structure of a single defect, calculate the exchange coupling between a pair of spin qubits, and identify possible avenues for further developments.
483 citations
Authors
Showing all 8962 results
Name | H-index | Papers | Citations |
---|---|---|---|
Ashok Kumar | 151 | 5654 | 164086 |
Hannu Kurki-Suonio | 138 | 433 | 99607 |
Nicolas Gisin | 125 | 827 | 64298 |
Anne Lähteenmäki | 116 | 485 | 81977 |
Riitta Hari | 111 | 491 | 43873 |
Andreas Richter | 110 | 769 | 48262 |
Mika Sillanpää | 96 | 1019 | 44260 |
Markku Leskelä | 94 | 876 | 36881 |
Ullrich Scherf | 92 | 735 | 36972 |
Mikko Ritala | 91 | 584 | 29934 |
Axel H. E. Müller | 89 | 564 | 30283 |
Karl Henrik Johansson | 88 | 1089 | 33751 |
T. Poutanen | 86 | 120 | 33158 |
Elina Lindfors | 86 | 420 | 23846 |
Günter Breithardt | 85 | 554 | 33165 |