Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Genetic instability in Streptomyces niveus plasmid pSN2: in vivo formation of deletion derivatives (1990)
    Springer
    Archives of microbiology 154 (1990), S. 504-509 
    Details
    ISSN: 1432-072X
    Keywords: Streptomyces niveus ; Plasmid pSN2 ; Plasmid instability ; In vivo deletions ; Broad host range
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A plasmid designated pSN2 (molecular size 32.0 kb) was isolated from the wild type of Streptomyces niveus ATCC 19793. To permit phenotypic identification of pSN2 the 1.9 kb BclI fragment was replaced in vitro by the 1.1 kb BclI fragment of pIJ702 carrying the thiostrepton resistance (tsr) gene to form the plasmid pSN3. pSN3 transforms S. lividans to thiostrepton resistance at high frequency and is stably maintained. However, when used to transform S. niveus pSN3 was unstable and produced a 5.5 kb thiostrepton resistant deletion derivative pLG5. pLG5 is also stable and expresses thiostrepton resistance in S. lividans but on transformation of S. niveus was unstable and produced a further thiostrepton resistant derivative, pLG10, of 6.5 kb. pLG5 and pLG10 like pSN3 transform S. lividans at high frequency and produce pocks. DNA hybridizations with a probe derived from pLG5 confirm that pLG5 is derived from DNA sequences present on pSN2 and pSN3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00245235
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Low-frequency measurements of cyclotron resonance in a high-mobility 2D electron gas in GaAs/AlGaAs heterostructures (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 4736-4738 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Cyclotron resonance in GaAs/AlGaAs heterostructures, containing a high-mobility two-dimensional electron gas (2DEG), has been investigated with the help of a resonator technique over the frequency range 26–34 GHz. Heterostructures with mobilities from 2×105 to 1.6×106 cm2/V s have been measured. The microwave conductivity of the 2DEG is well described by the Drude model and momentum relaxation time values are found to be close to dc values. The cyclotron mass was found to be 0.068±0.002m0.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352081
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A semiconductor source of triggered entangled photon pairs (2006)
    [s.l.] : Nature Publishing Group
    Nature 439 (2006), S. 179-182 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Entangled photon pairs are an important resource in quantum optics, and are essential for quantum information applications such as quantum key distribution and controlled quantum logic operations. The radiative decay of biexcitons—that is, states consisting of two bound ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature04446
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Modification of InAs quantum dot structure by the growth of the capping layer (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 49-51 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: InAs quantum dots inserted at the middle of a GaAs quantum well structure have been investigated by transmission electron microscopy and scanning transmission electron microscopy. We find that the growth condition of the overlayer on the InAs dots can lead to drastic changes in the structure of the dots. We attribute the changes to a combination of factors such as preferential growth of the overlayer above the wetting layers because of the strained surfaces and to the thermal instability of the InAs dots at elevated temperature. The result suggests that controlled sublimation, through suitable manipulation of the overlayer growth conditions, can be an effective tool to improve the structure of the self-organized quantum dots and can help tailor their physical properties to any specific requirements of the device applications. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.121719
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Transport properties of two-dimensional electron gases containing InAs self-assembled dots (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 2468-2470 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a study of the transport properties of two-dimensional electron gases formed in GaAs/AlGaAs heterostructures in which InAs self-assembled quantum dots have been inserted in the center of a GaAs quantum well. We observed that, while maintaining a constant carrier density, the mobility increased as the InAs dot density was reduced. The ratio of the transport to the quantum lifetime was measured to be approximately five with the dominant scattering mechanism attributed to short-range scattering from the inserted InAs dots. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.122484
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Low temperature operation of Ge-Ag ohmic contacts to a high mobility two dimensional electron gas (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 5883-5885 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ge-Ag ohmic contacts with good dimensional control to a two dimensional electron gas operating at low temperatures are demonstrated. At 4.2 K, the specific contact resistance lies in the range 2–5 Ω mm for anneals between 520 and 560 °C. The surface morphology is smooth, and the edge definition is of the order of 100 nm. Secondary ion mass spectroscopy analysis indicates that Ge diffusion is limited to within 2000 A(ring) of the surface for a concentration of 1017 cm−3 in samples annealed at 540 °C and below.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354163
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The effect of elevated atmospheric carbon dioxide levels on soil bacterial communities (2000)
    Oxford, UK : Blackwell Science Ltd
    Global change biology 6 (2000), S. 0 
    Details
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: The effect of elevated carbon dioxide levels on total bacterial communities was studied in a series of controlled and replicated model terrestrial ecosystems over a period of 38 weeks. The bacterial community was profiled using Denaturing Gradient Gel Electrophoresis (DGGE) analysis of bacterial 16S rRNA gene fragments amplified by the Polymerase Chain Reaction from DNA extracted directly from soil. Bacterial community DGGE profiles provided three major findings: (i) there was a high degree of profile similarity after ≈ 12 weeks (one plant generation); (ii) whilst overall DGGE profile was maintained over the 38 weeks (three plant generations), the banding patterns became more diverse with time; (iii) DGGE data provided no evidence for a shift in bacterial community structure resulting from exposure of the ecosystem to an increased atmospheric CO2 level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2486.2000.00320.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Effect of ion energy on Sn donor activation and defect production in molecular beam epitaxy GaAs doped with Sn ions during growth (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 4375-4381 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The production of electrically active defect centers in molecular beam epitaxy (MBE) GaAs irradiated with low energy (50–500 eV) Sn ions during growth has been investigated as a function of ion energy. GaAs was doped n type during growth with a specially designed Sn focused ion beam column mounted on a MBE growth chamber. The 77 and 300 K Hall mobility and carrier concentration of the GaAs depended strongly on the ion energy, thus providing a sensitive measure of the concentration of ion-induced acceptorlike defect centers. The material was found to be nonconducting for ion energies greater than 200 eV, while a systematic decrease in the acceptor concentration, and consequent increase in the mobility, was observed as the ion energy was decreased below this value. A peak mobility of 90 000 cm2 V−1 s−1 at a carrier concentration of 1×1014 cm−3 was achieved (at 60 K) which is in excess of that obtained in other reports of ion-doped GaAs. A similar dependence on ion energy was found in the 4.2 K photoluminescence spectra of the ion-doped GaAs, characterized by the appearance of a broad acceptor level peak and a decrease in the overall luminescent intensity with increasing ion energy. The lowest energy doped samples provided high quality spectra with narrow linewidths comparable with thermal (Si) doped material. Using the above data, a mechanism is proposed for the production of acceptor centers in this system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354405
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Electron transport across a wide AlGaAs barrier (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 5606-5621 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An experimental and theoretical study has been made of electron transport over a wide AlGaAs barrier with graded interfaces sandwiched between GaAs contact layers. The width of the central barrier region was varied between 700 and 2100 A(ring). Two series of samples with nominally identical structures but from different sources were investigated. Extensive measurements of both the voltage and temperature dependence of the current were made, as well as measurements of capacitance and magnetoresistance. Drift-diffusion thermionic emission theory has been used to interpret the data. Both numerical and analytical solutions of the model have been developed and were found to be in good agreement with each other. The presence of space charge in the barrier region, which has the effect of increasing the barrier height, was seen to be crucial to an understanding of the data. When the effect of space charge was included in the model good agreement was obtained between theory and experiment for electric fields up to 10 kV cm−1. The numerical solution required only one adjustable parameter, namely the value of the space-charge density. The parameters used in the analytical model were all derived from the experimental data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354222
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Raman studies of plasmon modes in a drifting two-dimensional electron gas (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 1701-1705 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present the first Raman-scattering studies of the behavior of the intrasubband plasmon mode of a two-dimensional electron gas which is undergoing lateral drift in an applied electric field. The data clearly show the expected Doppler shifts of the modes traveling up- and downstream, together with the expected dependence on the wave vector, but at higher drift velocities, the expected linear shift is distorted because of electron heating effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357684
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...