| 1. |
- Coll, M., et al.
(författare)
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Towards Oxide Electronics: a Roadmap
- 2019
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 482, s. 1-93
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Tidskriftsartikel (refereegranskat)abstract
- At the end of a rush lasting over half a century, in which CMOS technology has been experiencing a constant and breathtaking increase of device speed and density, Moore’s law is approaching the insurmountable barrier given by the ultimate atomic nature of matter. A major challenge for 21st century scientists is finding novel strategies, concepts and materials for replacing silicon-based CMOS semiconductor technologies and guaranteeing a continued and steady technological progress in next decades. Among the materials classes candidate to contribute to this momentous challenge, oxide films and heterostructures are a particularly appealing hunting ground. The vastity, intended in pure chemical terms, of this class of compounds, the complexity of their correlated behaviour, and the wealth of functional properties they display, has already made these systems the subject of choice, worldwide, of a strongly networked, dynamic and interdisciplinary research community. Oxide science and technology has been the target of a wide four-year project, named Towards Oxide-Based Electronics (TO-BE), that has been recently running in Europe and has involved as participants several hundred scientists from 29 EU countries. In this review and perspective paper, published as a final deliverable of the TO-BE Action, the opportunities of oxides as future electronic materials for Information and Communication Technologies ICT and Energy are discussed. The paper is organized as a set of contributions, all selected and ordered as individual building blocks of a wider general scheme. After a brief preface by the editors and an introductory contribution, two sections follow. The first is mainly devoted to providing a perspective on the latest theoretical and experimental methods that are employed to investigate oxides and to produce oxide-based films, heterostructures and devices. In the second, all contributions are dedicated to different specific fields of applications of oxide thin films and heterostructures, in sectors as data storage and computing, optics and plasmonics, magnonics, energy conversion and harvesting, and power electronics.
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| 2. |
- Fujita, S., et al.
(författare)
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Spatial and temporal variability of snow accumulation rate on the East Antarctic ice divide between Dome Fuji and EPICA DML
- 2011
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Ingår i: The Cryosphere. - : Copernicus GmbH. - 1994-0416 .- 1994-0424. ; 5:4, s. 1057-1081
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Tidskriftsartikel (refereegranskat)abstract
- To better understand the spatio-temporal variability of the glaciological environment in Dronning Maud Land (DML), East Antarctica, a 2800-km-long Japanese-Swedish traverse was carried out. The route includes ice divides between two ice-coring sites at Dome Fuji and EPICA DML. We determined the surface mass balance (SMB) averaged over various time scales in the late Holocene based on studies of snow pits and firn cores, in addition to radar data. We find that the large-scale distribution of the SMB depends on the surface elevation and continentality, and that the SMB differs between the windward and leeward sides of ice divides for strong-wind events. We suggest that the SMB is highly influenced by interactions between the large-scale surface topography of ice divides and the wind field of strong-wind events that are often associated with high-precipitation events. Local variations in the SMB are governed by the local surface topography, which is influenced by the bedrock topography. In the eastern part of DML, the accumulation rate in the second half of the 20th century is found to be higher by similar to 15% than averages over longer periods of 722 a or 7.9 ka before AD 2008. A similar increasing trend has been reported for many inland plateau sites in Antarctica with the exception of several sites on the leeward side of the ice divides.
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| 3. |
- Rafee, Sameh A.Abou, et al.
(författare)
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Spatial trends of extreme precipitation events in the Paraná river basin
- 2020
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Ingår i: Journal of Applied Meteorology and Climatology. - 1558-8424. ; 59:3, s. 443-454
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Tidskriftsartikel (refereegranskat)abstract
- This work presents an analysis of the observed trends in extreme precipitation events in the Paraná River basin (PRB) from 1977 to 2016 (40 yr) based on daily records from 853 stations. The Mann–Kendall test and inverse-distance-weighted interpolation were applied to annual and seasonal precipitation and also for four extreme precipitation indices. The results show that the negative trends (significance at 95% confidence level) in annual and seasonal series are mainly located in the northern and northeastern parts of the basin. In contrast, except in the autumn season, positive trends were concentrated in the southern and southeastern regions of the basin, most notably for annual and summer precipitation. The spatial distributions of the indices of annual maximum 5-day precipitation and number of rainstorms indicate that significant positive trends are mostly located in the south-southeast part of the basin and that significant negative trends are mostly located in the north-northeast part. The index of the annual number of dry days shows that 88% of significant trends are positive and that most of these are located in the northern region of the PRB, which is a region with a high number of consecutive dry days (>90). The simple daily intensity index showed the highest number of stations (263) with mostly positive significant trends.
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| 4. |
- Shoemaker, M. A., et al.
(författare)
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Design and validation of a trajectory estimation system for the Hayabusa sample return capsule
- 2010
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Ingår i: Spaceflight Mechanics 2010, Pts I-III. - : Univelt, Inc. - 9780877035602 ; , s. 375-394
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Konferensbidrag (refereegranskat)abstract
- The Japanese Hayabusa spacecraft will return to Earth in summer, 2010, carrying samples from asteroid Itokawa. Because the sample return capsule will reenter the atmosphere at night, the capsule and surrounding air will appear as a bright light (i.e., "fireball") during the portion of the trajectory with high aerodynamic heating. Kyushu University, in collaboration with the Japan Aerospace Exploration Agency, is developing a ground-based optical sensor system to observe the reentry and estimate the vehicle's trajectory. This paper describes the design and validation currently underway for the proposed system, in preparation for operations in mid-2010. An Extended Kalman Filter (EKF) is used to estimate the capsule's position and velocity, as well as a scale factor on the atmospheric density. Simulations of the EKF show that the capsule's state at the end of the visible portion of the trajectory (i.e., at approximately 25 km altitude) can be estimated with a 1-s uncertainty of 60 m in position and 8 m/s in velocity.
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| 5. |
- Zhang, Z. W., et al.
(författare)
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Boron effects on the ductility of a nano-cluster-strengthened ferritic steel
- 2011
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Ingår i: Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing. - : Elsevier BV. - 0921-5093. ; 528:3, s. 855-859
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical properties of Cu-rich nano-cluster-strengthened ferritic steels with and without boron doping were investigated. Tensile tests at room temperature in air showed that the B-doped ferritic steel has similar yield strength but a larger elongation than that without boron doping after extended aging at 500 degrees C. There are three mechanisms affecting the ductility and fracture of these steels: brittle cleavage fracture, week grain boundaries, and moisture-induced hydrogen embrittlement. Our study reveals that boron strengthens the grain boundary and suppresses the intergranular fracture. Furthermore, the moisture-induced embrittlement can be alleviated by surface coating with vacuum oil. (C) 2010 Elsevier B.V. All rights reserved.
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| 6. |
- Evander, Mikael, et al.
(författare)
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Using Acoustic Differential Extraction to enhance analysis of sexual assualt evidence on a valveless glass microdevice
- 2006
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Ingår i: Proceedings of µTAS 2006 Conference. ; 2, s. 1055-1057
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Konferensbidrag (refereegranskat)abstract
- The isolation of male and female DNA is an important step in the analysis of sexual assault evidence. A vaginal swab with female epithelial cells and male sperm cells is obtained from the female, and it is vital to separate the male and female fractions in order to obtain a single-source DNA profile of the suspect. In the case of a low abundance of sperm cells, it is very important that no cells are lost in the isolation step. The conventional isolation method used in the forensic DNA laboratories, differential extraction, is a time-consuming step, requiring up to 24 hours. It is neither highly amenable to automation, nor can it be easily integrated with other steps of the analysis. Therefore, a novel method of performing the isolation of male and female fractions of biological material from sexual assault evidence has been developed, termed acoustic differential extraction (ADE). After selectively lysing the female epithelial cells while keeping the sperm cells intact, the sample, now containing sperm cells and female cell lysate, is infused in a 900 μm wide and 70 μm deep microfabricated glass channel with miniature piezoelectric transducers mounted at the bottom of the channel, as shown in Figure 1. Upon activation of the ultrasound, the sperm cells will be trapped in a standing wave1 while free DNA will not be retained. The sperm cells, levitated in the 3D fluidic space above the transducer, can be washed with buffer and the unretained biological material directed to an output reservoir. Using laminar flow valving2, the sperm cells can be released and directed into a separate output reservoir in anticipation of DNA analysis, see Figure 2. With the purpose of evaluating the ADE microdevice for the collection of the two output fractions (male and female), preliminary work used a mock sexual assault sample created with polystyrene microparticles as sperm cells and Evan's Blue dye as female cell lysate. The particles were trapped over the transducer and the dye was directed to the female outlet reservoir as shown in Figure 3. After washing the particles, the ultrasound was deactivated and the flow redirected in order to collect the particles in the male outlet reservoir. A biological sample consisting of sperm cells and lysed female epithelial cells was subsequently tested by infusion into the device for five minutes while trapping the sperm cells over the transducer (Figure 4). The trapped sperm cells were washed with PBS for five minutes, then released and collected for analysis off-chip. DNA from the isolated cells was extracted with a commercial DNA extraction kit and analyzed with a duplex quantitative PCR assay3 to show the sample purity. An example of the qPCR data obtained is provided in Table 1. The results show that a highly-enriched sperm cell fraction can be obtained with the ADE technique. It is reasonable to expect that this technique can be integrated with on-chip downstream sample processing, e.g. DNA extraction and amplification. This would greatly diminish the analysis time from 24 hours to approximately 60 minutes. The time savings, in combination with the possibility to create a fully automated system, gives the ADE technique the potential to significantly alter the means by which sexual assault evidence is processed in crime laboratories today.
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| 7. |
- Liu, Zheng, et al.
(författare)
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A review of fine structures of nanoporous materials as evidenced by microscopic methods
- 2013
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Ingår i: Microscopy. - : Oxford University Press (OUP). - 2050-5698 .- 2050-5701. ; 62:1, s. 109-146
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Forskningsöversikt (refereegranskat)abstract
- This paper reviews diverse capabilities offered by modern electron microscopy techniques in studying fine structures of nanoporous crystals such as zeolites, silica mesoporous crystals, metal organic frameworks and yolk-shell materials. For the case of silica mesoporous crystals, new approaches that have been developed recently to determine the three-dimensionally periodic average structure, e. g., through self-consistent analysis of electron microscope images or through consideration of accidental extinctions, are presented. Various structural deviations in nanoporous materials from their average structures including intergrowth, surface termination, incommensurate modulation, quasicrystal and defects are demonstrated. Ibidem observations of the scanning electron microscope and atomic force microscope give information about the zeolite-crystal-growth mechanism, and an energy for unstitching a building-unit from a crystal surface is directly observed by an anatomic force microscope. It is argued how these observations lead to a deeper understanding of the materials.
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| 8. |
- Xu, X., et al.
(författare)
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Nanoscale phase separation in a fcc-based CoCrCuFeNiAl0.5 high-entropy alloy
- 2015
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454. ; 84, s. 145-152
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Tidskriftsartikel (refereegranskat)abstract
- Nano-scale phase separation is reported in a nominal single-phase, high-entropy alloy (HEA), which was characterized using scanning transmission electron microscopy (STEM) combined with atom probe tomography (APT). Despite the fact that X-ray diffraction exhibits a single face-centered-cubic (fcc) phase feature of the as-cast alloy prepared by melt spinning, selected area electron diffraction reveals weak L12 ordering in the as-spun alloy. High-resolution STEM shows the presence of two coherent nanophases with distinct L12 and fcc structures, coupling with compositional segregations. The ordering of the L12 domains is enhanced after annealing at 500 °C. Electron energy loss spectroscopy and APT analyses reveal that the L12 nano-phase is enriched with Fe, Co, Cr and Ni, while the fcc domains are a Cu-rich phase. The nano-scale phase separation can effectively minimize the lattice distortions caused by the atomic size difference in the constituent elements, which may offer structural insights into the unusual mechanical behavior and phase stability of fcc HEA.
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