| 1. |
- Ayala, Christopher L., et al.
(författare)
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Nanoelectromechanical digital logic circuits using curved cantilever switches with amorphous-carbon-coated contacts
- 2015
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Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 113, s. 157-166
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Tidskriftsartikel (refereegranskat)abstract
- Nanoelectromechanical (NEM) switches have the potential to complement or replace traditional CMOS transistors in the area of ultra-low-power digital electronics. This paper reports the demonstration of prototype circuits including the first 3-stage ring oscillator built using cell-level digital logic elements based on curved NEM switches. The ring oscillator core occupies an area of 30 mu m x 10 mu m using 6 NEM switches. Each NEM switch device has a footprint of 5 mu m x 3 mu m, an air gap of 60 mu m and is coated with amorphous carbon (a-C) for reliable operation. The ring oscillator operates at a frequency of 6.7 MHz, and confirms the simulated inverter propagation delay of 25 ns. The successful fabrication and measurement of this demonstrator are key milestones on the way towards an optimized, scaled technology with sub-nanosecond switching times, lower operating voltages and VLSI implementation.
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| 2. |
- Christoph, Richter, et al.
(författare)
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Identification of optimum molten salts for use as heat transfer fluids in parabolic trough CSP plants. A techno-economic comparative optimization
- 2017
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Ingår i: AIP Conference Proceedings. - : American Institute of Physics (AIP). - 0094-243X .- 1551-7616. - 9780735417571
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Tidskriftsartikel (refereegranskat)abstract
- Parabolic trough power plants using thermal oil as heat transfer fluid are the most mature concentrating solar power technology and state of the art. To further increase their efficiency and lower costs, molten salts can be used as heat transfer fluid. This results in higher operating temperature differences for improved cycle efficiencies and enables direct thermal energy storage at lower costs due to omission of the oil-to-salt heat exchanger and the need for smaller storage sizes. As a variety of salts are available to choose from, this study uses a multi-objective optimization to identify the most suitable heat transfer fluid for three locations in South Africa, Spain and Chile. The lowest values for the levelized costs of electricity (LCOE) can be found in Chile using Solar Salt as heat transfer fluid (75.0 $/MWhe). Generally, Solar Salt offers the lowest LCOE values followed by thermal oil and Hitec. The results also suggest that the choice of the heat transfer fluid is dependent on the direct normal irradiance (DNI) at each location. Thermal oil is competitive with Solar Salt in small systems at locations with low DNI values, whereas Hitec can be cheaper than thermal oil in large systems at locations with high DNI. Furthermore, it is also investigated at which freeze alert temperature set point the activation of the freeze protection system is optimal. The results indicate that this temperature should be chosen close to the solar field inlet temperature for small systems, while it can be lowered significantly for large systems to reduce electricity consumption from the freeze protection system.
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| 3. |
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| 4. |
- Herrholz, Andreas, et al.
(författare)
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The ANDRES Project : Analysis and Design of run-time Reconfigurable, heterogeneous Systems
- 2007
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Ingår i: Proceedings - 2007 International Conference on Field Programmable Logic and Applications, FPL. - : IEEE. - 9781424410606 - 1424410606 ; , s. 396-401
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Konferensbidrag (refereegranskat)abstract
- Today's heterogeneous embedded systems combine components from different domains, such as software, analogue hardware and digital hardware. The design and implementation of these systems is still a complex and error-prone task due to the different Models of Computations (MoCs), design languages and tools associated with each of the domains. Though making such systems adaptive is technologically feasible, most of the current design methodologies do not explicitely support adaptive architectures. This paper present the ANDRES project. The main objective of ANDRES is the development of a seamless design flow for adaptive heterogeneous embedded systems (AHES) based on the modelling language SystemC. Using domain-specific modelling extensions and libraries, ANDRES will provide means to efficiently use and exploit adaptivity in embedded system design. The design flow is completed by a methodology and tools for automatic hardware and software synthesis for adaptive architectures.
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| 5. |
- Hoetger, Alexander, et al.
(författare)
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Gate-Switchable Arrays of Quantum Light Emitters in Contacted Monolayer MoS2 van der Waals Heterodevices
- 2021
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Ingår i: Nano letters (Print). - : AMER CHEMICAL SOC. - 1530-6984 .- 1530-6992. ; 21:2, s. 1040-1046
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate electrostatic switching of individual, site-selectively generated matrices of single photon emitters (SPEs) in MoS2 van der Waals heterodevices. We contact monolayers of MoS2 in field-effect devices with graphene gates and hexagonal boron nitride as the dielectric and graphite as bottom gates. After the assembly of such gate-tunable heterodevices, we demonstrate how arrays of defects, that serve as quantum emitters, can be site-selectively generated in the monolayer MoS2 by focused helium ion irradiation. The SPEs are sensitive to the charge carrier concentration in the MoS2 and switch on and off similar to the neutral exciton in MoS2 for moderate electron doping. The demonstrated scheme is a first step for producing scalable, gate-addressable, and gate-switchable arrays of quantum light emitters in MoS2 heterostacks.
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| 6. |
- Klein, Julian, et al.
(författare)
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Engineering the Luminescence and Generation of Individual Defect Emitters in Atomically Thin MoS2
- 2021
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Ingår i: ACS Photonics. - : AMER CHEMICAL SOC. - 2330-4022. ; 8:2, s. 669-677
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the on-demand creation and positioning of photon emitters in atomically thin MoS2 with very narrow ensemble broadening and negligible background luminescence. Focused helium-ion beam irradiation creates 100s to 1000s of such mono-typical emitters at specific positions in the MoS2 monolayers. Individually measured photon emitters show anti-bunching behavior with a g(2)(0) similar to 0.23 and 0.27. From a statistical analysis, we extract the creation yield of the He-ion induced photon emitters in MoS2 as a function of the exposed area, as well as the total yield of single emitters as a function of the number of He ions when single spots are irradiated by He ions. We reach probabilities as high as 18% for the generation of individual and spectrally clean photon emitters per irradiated single site. Our results firmly establish 2D materials as a platform for photon emitters with unprecedented control of position as well as photophysical properties owing to the all-interfacial nature.
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| 7. |
- Seiboth, Frank, et al.
(författare)
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Aberration Correction for Hard X-ray Focusing at the Nanoscale
- 2017
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Ingår i: Advances in X-Ray/EUV Optics and Components XII. - : SPIE - International Society for Optical Engineering. - 9781510612303 - 9781510612297
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Konferensbidrag (refereegranskat)abstract
- We developed a corrective phase plate that enables the correction of residual aberration in reflective, diffractive, and refractive X-ray optics. The principle is demonstrated on a stack of beryllium compound refractive lenses with a numerical aperture of 0.49 x 10(-3) at three different synchrotron radiation and x-ray free-electron laser facilities. By introducing this phase plate into the beam path, we were able to correct the spherical aberration of the optical system and improve the Strehl ratio of the optics from 0.29(7) to 0.87(5), creating a diffraction-limited, large aperture, nanofocusing optics that is radiation resistant and very compact.
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| 8. |
- Seiboth, Frank, et al.
(författare)
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Perfect X-ray focusing via fitting corrective glasses to aberrated optics
- 2017
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Due to their short wavelength, X-rays can in principle be focused down to a few nanometres and below. At the same time, it is this short wavelength that puts stringent requirements on X-ray optics and their metrology. Both are limited by today’s technology. In this work, we present accurate at wavelength measurements of residual aberrations of a refractive X-ray lens using ptychography to manufacture a corrective phase plate. Together with the fitted phase plate the optics shows diffraction-limited performance, generating a nearly Gaussian beam profile with a Strehl ratio above 0.8. This scheme can be applied to any other focusing optics, thus solving the X-ray optical problem at synchrotron radiation sources and X-ray free-electron lasers.
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| 9. |
- Uhlén, Fredrik, et al.
(författare)
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Ronchi test for characterization of X-ray nanofocusing optics and beamlines
- 2014
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 21, s. 1105-1109
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Tidskriftsartikel (refereegranskat)abstract
- A Ronchi interferometer for hard X-rays is reported in order to characterize the performance of the nanofocusing optics as well as the beamline stability. Characteristic interference fringes yield qualitative data on present aberrations in the optics. Moreover, the visibility of the fringes on the detector gives information on the degree of spatial coherence in the beamline. This enables the possibility to detect sources of instabilities in the beamline like vibrations of components or temperature drift. Examples are shown for two different nanofocusing hard X-ray optics: a compound refractive lens and a zone plate.
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| 10. |
- Wayne, Greg, et al.
(författare)
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Principles of Systems Biology, No. 11
- 2016
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Ingår i: CELL SYSTEMS. - : CELL PRESS. - 2405-4712. ; 3:5, s. 406-410
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Tidskriftsartikel (refereegranskat)abstract
- This month: AI that learns patterns and facts, new protein-RNA and protein-protein relationships, engineering signaling and metabolism, and more variants of Cas9.
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