| 1. |
- Gard, G, et al.
(author)
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Stress and qualification of computer work
- 1989
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In: Work with display units 89: Selected papers from the second international conference of work with display units (Eds. L Berlinguet, D Berthelette.
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Book chapter (other academic/artistic)
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| 2. |
- Gogova, Daniela, et al.
(author)
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Epitaxial growth of β -Ga 2 O 3 by hot-wall MOCVD
- 2022
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In: AIP Advances. - : AIP Publishing. - 2158-3226. ; 12:5, s. 055022-055022
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Journal article (peer-reviewed)abstract
- The hot-wall metalorganic chemical vapor deposition (MOCVD) concept, previously shown to enable superior material quality and highperformance devices based on wide bandgap semiconductors, such as Ga(Al)N and SiC, has been applied to the epitaxial growth ofβ-Ga2O3. Epitaxial β-Ga2O3 layers at high growth rates (above 1 μm/h), at low reagent flows, and at reduced growth temperatures(740 ○C) are demonstrated. A high crystalline quality epitaxial material on a c-plane sapphire substrate is attained as corroborated by a combination of x-ray diffraction, high-resolution scanning transmission electron microscopy, and spectroscopic ellipsometry measurements. Thehot-wall MOCVD process is transferred to homoepitaxy, and single-crystalline homoepitaxial β-Ga2O3 layers are demonstrated with a 201 ¯rocking curve width of 118 arc sec, which is comparable to those of the edge-defined film-fed grown (201) ¯ β-Ga2O3 substrates, indicative ofsimilar dislocation densities for epilayers and substrates. Hence, hot-wall MOCVD is proposed as a prospective growth method to be furtherexplored for the fabrication of β-Ga2O3
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| 3. |
- Gogova, Daniela, 1967-, et al.
(author)
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Epitaxial growth of β-Ga2O3 by hot-wall MOCVD
- 2022
-
In: AIP Advances. - : AIP Publishing. - 2158-3226. ; 12:5
-
Journal article (peer-reviewed)abstract
- The hot-wall metalorganic chemical vapor deposition (MOCVD) concept, previously shown to enable superior material quality and high performance devices based on wide bandgap semiconductors, such as Ga(Al)N and SiC, has been applied to the epitaxial growth of beta-Ga2O3. Epitaxial beta-Ga2O3 layers at high growth rates (above 1 mu m/h), at low reagent flows, and at reduced growth temperatures (740 degrees C) are demonstrated. A high crystalline quality epitaxial material on a c-plane sapphire substrate is attained as corroborated by a combination of x-ray diffraction, high-resolution scanning transmission electron microscopy, and spectroscopic ellipsometry measurements. The hot-wall MOCVD process is transferred to homoepitaxy, and single-crystalline homoepitaxial beta-Ga2O3 layers are demonstrated with a 201 rocking curve width of 118 arc sec, which is comparable to those of the edge-defined film-fed grown (201) beta-Ga2O3 substrates, indicative of similar dislocation densities for epilayers and substrates. Hence, hot-wall MOCVD is proposed as a prospective growth method to be further explored for the fabrication of beta-Ga2O3.
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| 4. |
- Ahlén, Olof, et al.
(author)
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Fourier coefficients attached to small automorphic representations of SLn (A)
- 2018
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In: Journal of Number Theory. - : Elsevier BV. - 0022-314X .- 1096-1658. ; 192, s. 80-142
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Journal article (peer-reviewed)abstract
- We show that Fourier coefficients of automorphic forms attached to minimal or next-to-minimal automorphic representations of SLn(A) are completely determined by certain highly degenerate Whittaker coefficients. We give an explicit formula for the Fourier expansion, analogously to the Piatetski-Shapiro–Shalika formula. In addition, we derive expressions for Fourier coefficients associated to all maximal parabolic subgroups. These results have potential applications for scattering amplitudes in string theory.
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| 5. |
- Björk, Glenn, et al.
(author)
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A conserved modified wobble nucleoside (mcm5s2U) in lysyl-tRNA is required for viability in yeast.
- 2007
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In: RNA. - : Cold Spring Harbor Laboratory. - 1355-8382 .- 1469-9001. ; 13:8, s. 1245-55
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Journal article (peer-reviewed)abstract
- Transfer RNAs specific for Gln, Lys, and Glu from all organisms (except Mycoplasma) and organelles have a 2-thiouridine derivative (xm(5)s(2)U) as wobble nucleoside. These tRNAs read the A- and G-ending codons in the split codon boxes His/Gln, Asn/Lys, and Asp/Glu. In eukaryotic cytoplasmic tRNAs the conserved constituent (xm(5)-) in position 5 of uridine is 5-methoxycarbonylmethyl (mcm(5)). A protein (Tuc1p) from yeast resembling the bacterial protein TtcA, which is required for the synthesis of 2-thiocytidine in position 32 of the tRNA, was shown instead to be required for the synthesis of 2-thiouridine in the wobble position (position 34). Apparently, an ancient member of the TtcA family has evolved to thiolate U34 in tRNAs of organisms from the domains Eukarya and Archaea. Deletion of the TUC1 gene together with a deletion of the ELP3 gene, which results in the lack of the mcm(5) side chain, removes all modifications from the wobble uridine derivatives of the cytoplasmic tRNAs specific for Gln, Lys, and Glu, and is lethal to the cell. Since excess of the unmodified form of these three tRNAs rescued the double mutant elp3 tuc1, the primary function of mcm(5)s(2)U34 seems to be to improve the efficiency to read the cognate codons rather than to prevent mis-sense errors. Surprisingly, overexpression of the mcm(5)s(2)U-lacking tRNA(Lys) alone was sufficient to restore viability of the double mutant.
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| 6. |
- Björk, Glenn R, et al.
(author)
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A primordial tRNA modification required for the evolution of life?
- 2001
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In: EMBO Journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 20:1-2, s. 231-239
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Journal article (peer-reviewed)abstract
- The evolution of reading frame maintenance must have been an early event, and presumably preceded the emergence of the three domains Archaea, Bacteria and Eukarya. Features evolved early in reading frame maintenance may still exist in present-day organisms. We show that one such feature may be the modified nucleoside 1-methylguanosine (m(1)G37), which prevents frameshifting and is present adjacent to and 3' of the anticodon (position 37) in the same subset of tRNAs from all organisms, including that with the smallest sequenced genome (Mycoplasma genitalium), and organelles. We have identified the genes encoding the enzyme tRNA(m(1)G37)methyltransferase from all three domains. We also show that they are orthologues, and suggest that they originated from a primordial gene. Lack of m(1)G37 severely impairs the growth of a bacterium and a eukaryote to a similar degree. Yeast tRNA(m(1)G37)methyltransferase also synthesizes 1-methylinosine and participates in the formation of the Y-base (yW). Our results suggest that m(1)G37 existed in tRNA before the divergence of the three domains, and that a tRNA(m(1)G37)methyltrans ferase is part of the minimal set of gene products required for life.
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| 7. |
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| 8. |
- Håkansson, P, et al.
(author)
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Itô diffusions on hypersurfaces with application to the Schwarz-P surface and nuclear magnetic resonance theory
- 2002
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In: The Journal of Chemical Physics. ; 117:19, s. 8634-43
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Journal article (peer-reviewed)abstract
- This work presents a new Brownian dynamics simulation method of translational diffusion on curved surfaces. This new method introduce any implicit defined surface into the stochastic differential equation describing Brownian motion on that surface. The surface curvature will thus enter the force term (A) in the stochastic differential equation dXt = A(Xt)dt + B(Xt)dWt describing an Itô process. We apply the method calculating time correlation functions relevant in nuclear magnetic resonance (NMR) relaxation and translational diffusion studies of cubic phases of lyotropic systems. In particularly we study some bicontinuous cubic liquid crystalline phases which can be described as triply periodic minimal surfaces. The curvature dependent spin relaxation of the Schwarz-P minimal surface is calculated. A comparison of relaxation is made with the more complex topology of the Neovius surface which is another minimal surface in the same space group, and with parallel displacement of the minimal surface which thus results in a nonminimal surface. The curvature dependent relaxation effects are determined by calculating the translational diffusion modulated time-correlation function which determine the relaxation rates of a quadrupole nuclei residing in the water–lipid interface. The results demonstrates that spin relaxation data can provide quantitative information about micro-structure of biocontinuous cubic phases and that it is sensitive to the topology of the surface and to parallel displacement of the model surface. Consequently, spin relaxation may be used as a complement to x-ray diffraction in order to discriminate between different microstructures. It is concluded that fast and accurate computer simulations experiments is needed to be able to interpret NMR relaxation experiments on curved surfaces. © 2002 American Institute of Physics.
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| 9. |
- Lidell, Martin, 1970, et al.
(author)
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Evidence for two types of brown adipose tissue in humans
- 2013
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In: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 19:5, s. 631-634
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Journal article (peer-reviewed)abstract
- The previously observed supraclavicular depot of brown adipose tissue (BAT) in adult humans was
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| 10. |
- Mukherjee, S., et al.
(author)
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Role of boron diffusion in CoFeB/MgO magnetic tunnel junctions
- 2015
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In: Physical Review B. - 1098-0121 .- 1550-235X. ; 91:8
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Journal article (peer-reviewed)abstract
- Several scientific issues concerning the latest generation read heads for magnetic storage devices, based on CoFeB/MgO/CoFeBmagnetic tunnel junctions (MTJs) are known to be controversial, including such fundamental questions as to the behavior and the role of B in optimizing the physical properties of these devices. Quantitatively establishing the internal structures of several such devices with different annealing conditions using hard x-ray photoelectron spectroscopy, we resolve these controversies and establish that the B diffusion is controlled by the capping Ta layer, though Ta is physically separated from the layer with B by several nanometers. While explaining this unusual phenomenon, we also provide insight into why the tunneling magnetoresistance (TMR) is optimized at an intermediate annealing temperature, relating it to B diffusion, coupled with our studies based on x-ray diffraction and magnetic studies.
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