| 1. |
- Gällström, Andreas, et al.
(författare)
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A defect center for quantum computing : Mo in SiC
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The electronic structure and vibrational properties of molybdenum (Mo) in SiC are analyzed and investigated in detail. Mo is considered as occupying the silicon-carbon divacancy in the so-called asymmetric split vacancy (ASV) configuration. Group-theoretical considerations within this model are used to explain the experimental results (optical properties and behavior in magnetic field). The vibrational properties of the defect are studied using simple the “defect molecule” model with parameters determined phenomenologically from the experimental data. The position of Mo in the ASV configuration deduced from this model is shown to be in good agreement with the earlier reported data from ab initio supercell calculations. The usefulness of molybdenum in SiC in quantum computing is investigated, and it shown that Mo is a highly promising candidate for quantum computing.
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| 2. |
- Gällström, Andreas, et al.
(författare)
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Optical identification of intrinsic nearest-neighbor defects in SiC
- 2015
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The optical signature of two types of intrinsic nearest-neighbor defects in SiC is observed in 4H- and 6H-SiC. The first optical signature belong to a defect previously known as UD-2 and identified as the divacancy pair, and the second – to a defect referred to here as UD-0, an unidentified defect. In both these defects, the number of optical centers is equal to the number of possible configurations for nearest-neighbor pairs in the unit cells of these polytypes. The polarization of all optical transitions is investigated. The formation of the two defects by means of electron irradiation and subsequent annealing in samples with different Fermi levels is studied, too. The observed transitions are investigated using group-theoretical analysis and UD-0 is tentatively assigned to the carbon-vacancy carbonantisite pair, based on energy positions of the lines and spin configuration.
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| 3. |
- Lagerkvist, C.-I., et al.
(författare)
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1995 GY7
- 1995
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Ingår i: 1995MPEC....M...02L.
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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| 4. |
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| 5. |
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| 6. |
- Olofsson, Per, et al.
(författare)
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A collagen-based microwell migration assay to study NK—target cell interactions
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Natural killer (NK) cell cytotoxicity is highly dependent on the ability of NK cells to migrate through the extracellular matrix (ECM) microenvironment. Traditional imaging studies of NK cell migration and cytotoxicity have utilized 2-D surfaces, which do not properly reproduce the structural and mechanical cues that shape the migratory response of NK cells in vivo. In addition, current in vivo imaging does not allow for the accurate long-term single-cell imaging required to dissect the functional heterogeneity of NK cell populations, and importantly, it does not allow studies of human cells. Therefore, it is desirable to implement in vitro migration and killing assays that better mimic in vivo conditions.We have combined a microwell assay that allows long-term imaging and tracking of small, well-defined populations of NK cells with an interstitial ECM-like matrix to more closely approximate in vivo conditions. The microwells, which are loaded with a gel mixture containing NK and target cells, allows for long-term imaging of NK–target cell interactions within a confined 3-D volume. The microwells were optically sectioned by confocal fluorescence microscopy once every 2 min for 12 h. NK cells were tracked by the Baxter Algorithms to assess motility parameters and interactions with target cells were manually scored for duration and outcome.We found marked differences in motility between individual cells with a significant fraction of the cells moving slowly and being confined to a small area within the matrix, while other cells moved more freely, probably reflecting local variations in the matrix structure and inherent difference in motility between individual cells. A majority of NK cells also exhibited transient variation in their mobility alternating between periods of migration arrest and random movement. NK cells that alternated between different modes of migration switched on average once every 3 h.NK cells made fewer and shorter contacts with target cells than in comparable 2-D assays. The difference was particularly pronounced for the process of post-conjugation attachment when NK and target cells separate. The timing of this process is likely influenced by a biomechanical component only present in 3-D environments where the cells are offered multiple anchor points with the matrix that can be used to generate the forces needed to pull apart.The developed microwell-based assay is suitable for 3-D time-lapse imaging of NK cells migration and cytotoxicity. As it allows for experiments with human cells, it could be used as a complement to in vivo imaging to study the influence of e.g. education and cytokine activation on NK cell heterogeneity in migration and cytotoxicity.
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| 7. |
- Yajnanarayana, Vijaya, et al.
(författare)
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Optimal Scheduling for Interference Mitigation by Range Information
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This paper describes several algorithms for generating an optimal schedule for multiple access on a shared channel by utilizing range information in a fully connected network. We also provide detailed analysis for the proposed algorithms in terms of their complexity, convergence, and effect of non-idealities in the network. The performance of the proposed schemes are compared with non-aided methods to quantify the benefits of using the range information in the communication. We argue that the proposed techniques yield significant benefits as the number of nodes in the network increases. We provide simulation results in support of the claim. The proposed methods indicate that the throughput can be increased on average by 3-10 times for typical network configurations.
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