| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Fuhrer, Andreas, et al.
(författare)
-
Fano effect in a quantum-ring-quantum-dot system with tunable coupling
- 2006
-
Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 73:20
-
Tidskriftsartikel (refereegranskat)abstract
- Transport measurements are presented on a quantum ring that is tunnel-coupled to a quantum dot. When the dot is in the Coulomb blockade regime, but strongly coupled to the open ring, Fano line shapes are observed in the current through the ring, when the electron number in the dot changes by 1. The symmetry of the Fano resonances is found to depend on the magnetic flux penetrating the area of the ring and on the strength of the ring-dot coupling. At temperatures above T=0.65 K the Fano effect disappears, while the Aharonov-Bohm interference in the ring persists up to T=4.2 K. Good agreement is found between these experimental observations and a single-channel scattering matrix model including decoherence in the dot.
|
|
| 6. |
|
|
| 7. |
- Fuhrer, C., et al.
(författare)
-
The influence of non-equilibrium wet steam effects on the aeroelastic properties of a turbine blade row
- 2016
-
Ingår i: Proceedings of the ASME Turbo Expo. - : ASME Press. - 9780791849866
-
Konferensbidrag (refereegranskat)abstract
- Turbine blade flutter is a concern for the manufacturers o steam turbines. Typically, the length of last stage blades of larg steam turbines is over one meter. These long blades are susceptibl to flutter because of their low structural frequency an supersonic tip speeds with oblique shocks and their reflections Although steam condensation has usually occurred by the las stage, ideal gas is mostly assumed when performing flutter analysi for steam turbines The results of a flutter analysis of a 2D steam turbine tes case which examine the influence of non-equilibrium wet stea are presented. The geometry and flow conditions of the test cas are supposed to be similar to the flow near the tip in a stea turbine as this is where most of the unsteady aerodynamic wor contributing to flutter is done. The unsteady flow simulation required for the flutter analysis are performed by ANSYS CFX Three fluid models are examined: ideal gas, equilibrium we steam (EQS) and non-equilibrium wet steam (NES), of whic NES reflects the reality most Previous studies have shown that a good agreement betwee ideal gas and EQS simulations can be achieved if the prescribe ratio of specific heats is equal to the equilibrium polytropic inde of the wet steam flow through the turbine.
|
|
| 8. |
- Nilsson, Lars-Göran, et al.
(författare)
-
Cognitive test battery of CASCADE : Tasks and data.
- 2005
-
Ingår i: Aging, Neuropsychology and Cognition. - 1382-5585. ; 12:1, s. 32-56
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the cognitive test battery used in the CASCADE Study (Cardiovascular Determinants of Dementia) for examining the consequences of cerebral white matter lesions and atrophy. The test battery includes nine different tasks assessing memory, executive function, and global cognitive function. Three episodic memory tasks were used in combinations to assess the role of attention and speed on encoding. Estimates of short- and long-term memory capacity were also derived from these three memory tasks. Semantic memory production / frontal lobe functions were assessed by means of a word fluency test. The Letter Digit Substitution test and the Stroop test were used to assess speed of processing and attention. Motor speed was measured with the Purdue Pegboard test, and global cognitive function was assessed by the Mini Mental State Examination. Overall performance data for the whole CASCADE sample and for each of eight study centers are presented for each test. Possible reasons for performance differences among study centers are discussed.
|
|
| 9. |
- Rasmussen, Sune Olander, et al.
(författare)
-
Ice-core data used for the construction of the Greenland Ice-Core Chronology 2005 and 2021 (GICC05 and GICC21)
- 2023
-
Ingår i: Earth System Science Data. - 1866-3508 .- 1866-3516. ; 15:8, s. 3351-3364
-
Tidskriftsartikel (refereegranskat)abstract
- We here describe, document, and make available a wide range of data sets used for annual-layer identification in ice cores from DYE-3, GRIP, NGRIP, NEEM, and EGRIP. The data stem from detailed measurements performed both on the main deep cores and shallow cores over more than 40 years using many different setups developed by research groups in several countries and comprise both discrete measurements from cut ice samples and continuous-flow analysis data.The data series were used for counting annual layers 60 000 years back in time during the construction of the Greenland Ice-Core Chronology 2005 (GICC05) and/or the revised GICC21, which currently only reaches 3800 years back. Now that the underlying data are made available (listed in Table 1) we also release the individual annual-layer positions of the GICC05 timescale which are based on these data sets.We hope that the release of the data sets will stimulate further studies of the past climate taking advantage of these highly resolved data series covering a large part of the interior of the Greenland ice sheet.
|
|
| 10. |
- Yi, Chuixiang, et al.
(författare)
-
Climate control of terrestrial carbon exchange across biomes and continents
- 2010
-
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 5:3
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere across biomes and continents are lacking. Here we present data describing the relationships between net ecosystem exchange of carbon (NEE) and climate factors as measured using the eddy covariance method at 125 unique sites in various ecosystems over six continents with a total of 559 site-years. We find that NEE observed at eddy covariance sites is (1) a strong function of mean annual temperature at mid-and high-latitudes, (2) a strong function of dryness at mid-and low-latitudes, and (3) a function of both temperature and dryness around the mid-latitudinal belt (45 degrees N). The sensitivity of NEE to mean annual temperature breaks down at similar to 16 degrees C (a threshold value of mean annual temperature), above which no further increase of CO2 uptake with temperature was observed and dryness influence overrules temperature influence.
|
|
| 11. |
- Arévalo, Carmen, et al.
(författare)
-
A collocation formulation of multistep methods for variable step-size extensions
- 2002
-
Ingår i: Applied Numerical Mathematics. - 0168-9274. ; 42:1-3, s. 5-16
-
Tidskriftsartikel (refereegranskat)abstract
- Multistep methods are classically constructed by specially designed difference operators on an equidistant time grid. To make them practically useful, they have to be implemented by varying the step-size according to some error-control algorithm. It is well known how to extend Adams and BDF formulas to a variable step-size formulation. In this paper we present a collocation approach to construct variable step-size formulas. We make use of piecewise polynomials to show that every k-step method of order k + I has a variable step-size polynomial collocation formulation. (C) 2002 IMACS. Published by Elsevier Science B.V. All rights reserved.
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
- Ghandriz, Toheed, et al.
(författare)
-
Structural Optimization of Multibody Systems
- 2015
-
Ingår i: Proceedings of the ECCOMAS Thematic Conference on Multibody Dynamics 2015. - 9788494424403 ; , s. 828-838
-
Konferensbidrag (refereegranskat)abstract
- Flexible multibody dynamics (FMD) has found many applications in control, analysis and design of mechanical systems. FMD together with the theory of structural optimization can be used for designing multibody systems with bodies which are lighter, but stronger. Topology optimization of static structures is an active research topic in structural mechanics. However, the extension to the dynamic case is less investigated as one has to face serious numerical difficulties. One way of extending static structural topology optimization to topology optimization of dynamic flexible multibody system with large rotational and transitional motion is investigated in this paper. The optimization can be performed simultaneously on all flexible bodies. The simulation part of optimization is based on an FEM approach together with modal reduction. The resulting nonlinear differential-algebraic systems are solved with the error controlled integrator IDA (Sundials) wrapped into Python environment by Assimulo. A modified formulation of solid isometric material with penalization (SIMP) method is suggested to avoid numerical instabilities and convergence failures of the optimizer. Sensitivity analysis is central in structural optimization. The sensitivities are approximated to circumvent the expensive calculations. The provided examples show that the method is indeed suitable for optimizing a wide range of multibody systems. Standard SIMP method in structural topology optimization suggests stiffness penalization. To overcome the problem of instabilities and mesh distortion in the dynamic case we consider here additionally element mass penalization.
|
|
| 15. |
- Grubisic-Cabo, Antonija, et al.
(författare)
-
Magnesium-intercalated graphene on SiC : Highly n-doped air-stable bilayer graphene at extreme displacement fields
- 2021
-
Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 541
-
Tidskriftsartikel (refereegranskat)abstract
- We use angle-resolved photoemission spectroscopy to investigate the electronic structure of bilayer graphene at high n-doping and extreme displacement fields, created by intercalating epitaxial monolayer graphene on silicon carbide with magnesium to form quasi-freestanding bilayer graphene on magnesium-terminated silicon carbide. Angle-resolved photoemission spectroscopy reveals that upon magnesium intercalation, the single massless Dirac band of epitaxial monolayer graphene is transformed into the characteristic massive double-band Dirac spectrum of quasi-freestanding bilayer graphene. Analysis of the spectrum using a simple tight binding model indicates that magnesium intercalation results in an n-type doping of 2.1 x 10(14) cm(-2) and creates an extremely high displacement field of 2.6 V/nm, thus opening a considerable gap of 0.36 eV at the Dirac point. This is further confirmed by density-functional theory calculations for quasi-freestanding bilayer graphene on magnesium-terminated silicon carbide, which show a similar doping level, displacement field and bandgap. Finally, magnesium-intercalated samples are surprisingly robust to ambient conditions; no significant changes in the electronic structure are observed after 30 min exposure to air.
|
|
| 16. |
- Kennergren, Charles, 1948, et al.
(författare)
-
Laser-assisted lead extraction: the European experience.
- 2007
-
Ingår i: Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology. - : Oxford University Press (OUP). - 1099-5129. ; 9:8, s. 651-6
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: The aim of this study is to investigate the safety and effectiveness of Excimer laser-assisted lead extraction in Europe. The final European multi-centre study experience is presented. METHOD AND RESULTS: The Excimer is a cool cutting laser (50 degrees C) with a wavelength of 308 nm. The energy is emitted from the tip of a flexible sheath and is absorbed by proteins and lipids, 64% of the energy is absorbed at a tissue depth of 0.06 mm. The sheath is positioned over the lead, and the fibrosis surrounding the lead is vaporized while advancing the sheath without damaging other leads. From August 1996 to March 2001, 383 leads (170 atrial, 213 ventricular) in 292 patients (mean age 61.6 years, range 13-96) were extracted at 14 European centres. Mean implantation time was 74 months (3-358). Most frequent indications were pocket infection (26%), non-functional leads (21%), patient morbidity (21%), septicaemia or endocarditis (14%), erosion (5%), and lead interference (8%). Median extraction time was 15 min (1-300). Complete extraction was achieved in 90.9% of the leads and partial extraction in 3.4%. Extraction failed in 5.7% of the leads. Major complications = perforations caused 10/22 (3.4/5.7%) of the failures. Most partially extracted patients were considered clinically successful, as only minor lead parts without clinical significance were left. Femoral non-laser technique was used to remove 8/12 of the non-complication failures. The total complication rate, including five minor complications (1.7%), was 5.1%. No in-hospital mortality occurred. CONCLUSION: Pacing and implantable cardioverter-defibrillator leads can safely, effectively, and predictably be extracted. Open-heart extractions can be limited to special cases. The results indicate that the traditional policy of abandoning redundant leads, instead of removing them, may be obsolete in many patients.
|
|
| 17. |
|
|
| 18. |
- Roddaro, Stefano, et al.
(författare)
-
Spin States of holes in ge/si nanowire quantum dots.
- 2008
-
Ingår i: Physical Review Letters. - 1079-7114. ; 101:18
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate tunable hole quantum dots defined by surface gating Ge/Si core-shell nanowire heterostructures. In single level Coulomb-blockade transport measurements at low temperatures spin doublets are found, which become sequentially filled by holes. Magnetotransport measurements allow us to extract a g factor g;{*} approximately 2 close to the value of a free spin-1/2 particle in the case of the smallest dot. In less confined quantum dots smaller g factor values are observed. This indicates a lifting of the expected strong spin-orbit interaction effects in the valence band for holes confined in small enough quantum dots. By comparing the excitation spectrum with the addition spectrum we tentatively identify a hole exchange interaction strength chi approximately 130 mueV.
|
|
| 19. |
- Scheiblbrandner, Stefan, et al.
(författare)
-
Evolving stability and pH-dependent activity of the high redox potential Botrytis aclada laccase for enzymatic fuel cells
- 2017
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Fungal high redox potential laccases are proposed as cathodic biocatalysts in implantable enzymatic fuel cells to generate high cell voltages. Their application is limited mainly through their acidic pH optimum and chloride inhibition. This work investigates evolutionary and engineering strategies to increase the pH optimum of a chloride-tolerant, high redox potential laccase from the ascomycete Botrytis aclada. The laccase was subjected to two rounds of directed evolution and the clones screened for increased stability and activity at pH 6.5. Beneficial mutation sites were investigated by semi-rational and combinatorial mutagenesis. Fourteen variants were characterised in detail to evaluate changes of the kinetic constants. Mutations increasing thermostability were distributed over the entire structure. Among them, T383I showed a 2.6-fold increased half-life by preventing the loss of the T2 copper through unfolding of a loop. Mutations affecting the pH-dependence cluster around the T1 copper and categorise in three types of altered pH profiles: pH-type I changes the monotonic decreasing pH profile into a bell-shaped profile, pH-type II describes increased specific activity below pH 6.5, and pH-type III increased specific activity above pH 6.5. Specific activities of the best variants were up to 5-fold higher (13 U mg(-1)) than BaL WT at pH 7.5.
|
|
| 20. |
|
|
