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
    An analysis of temperature dependent photoluminescence line shapes in InGaN (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 1697-1699 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence (PL) line shapes in InGaN multiple quantum well structures have been studied experimentally and theoretically between 10 and 300 K. The higher temperature PL spectra can be fitted quantitatively with a thermalized carrier distribution and a broadened joint-density-of-states. The low temperature PL line shapes suggest that carriers are not thermalized, as a result of localization by band-gap fluctuations. We deduce a localization energy of ∼7 meV as compared with an activation energy of ∼63 meV from thermal quenching of the PL intensity. We thus conclude that this activation energy and the band-gap fluctuation most likely have different origins. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.122249
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Selective excitation and thermal quenching of the yellow luminescence of GaN (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 3273-3275 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the observation of narrower structures in the yellow luminescence of bulk and thin-film n-type GaN, using the technique of selective excitation. These fine structures exhibit thermal quenching associated with an activated behavior. We attribute these fine structures to phonons and electronic excitations of a shallow donor-deep acceptor complex, and determine its activation energy for delocalization. Our results suggest that in addition to distant donor-acceptor pairs, the yellow luminescence can also involve emission complexes of shallow donors and deep acceptors. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.125322
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    What determines the emission peak energy of the blue luminescence in highly Mg-doped p-GaN? (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 2500-2502 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report a study of the 2.8 eV blue luminescence (BL) in heavily Mg-doped p-GaN via resonant excitation with a tunable blue dye laser. The dependence of the BL on the excitation photon energy (Eex) is unlike that of the yellow luminescence found in n-type GaN. An Urbach-type band tail, with Urbach parameter of 33 meV is observed in the vicinity of the BL energy. We propose that the peak energy of the BL marks the transition from localized states to delocalized states within this band tail. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1367904
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Reduced Ca Currents in Frog Nerve Terminals at High Pressure (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 635 (1991), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1991.tb36512.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Alterations in brain monoamine neurotransmitter release at high pressure (1989)
    Springer
    Experimental brain research 78 (1989), S. 179-184 
    Details
    ISSN: 1432-1106
    Keywords: Neurotransmitter ; High pressure nervous syndrome ; Synaptosome ; Monoamine ; Pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary High pressure exposure produces neurological changes which manifest as tremors, EEG changes and convulsions. Since previous studies have implicated the involvement of the monoaminergic system in these symptoms, it was of interest to study monoamine release at high pressure. Synaptosomes isolated from guinea pig brain were used to follow monoamine efflux at 68 ATA. The major observation was a decrease in the initial calcium dependent release of all three monoamines in response to K+ induced depolarization. This response is similar to that previously observed for GABA, glycine and glutamate. This generalized pressure induced depression of initial transmitter release suggests a mechanism common to the release process for both excitatory and inhibitory neurotransmission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230697
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A 23187-stimulated calcium uptake and GABA release by cerebrocortical synaptosomes: effects of high pressure (1991)
    Springer
    Journal of neural transmission 86 (1991), S. 1-9 
    Details
    ISSN: 1435-1463
    Keywords: Pressure ; A23187 ; ionophore ; HPNS ; GABA release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Guinea pig cerebrocortical synaptosome preparations were used to study the effect of compression to 62 ATA on45Ca2+ uptake and [3H]GABA release using a calcium ionophore A23187, which bypasses the voltage-sensitive calcium channel. Pressure was found to exert a suppressive effect on the A 23187-induced release of [3H]GABA, while having no significant effect on A 23187-stimulated45Ca2+ uptake. On the other hand, both depolarization-induced45Ca2+ uptake and [3H]GABA release were inhibited by pressure exposure. These results suggest that pressure may suppress GABA release by affecting pre-synaptic events subsequent to calcium influx.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01250371
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    A method of object-oriented information management for layout design (1996)
    Springer
    Engineering with computers 12 (1996), S. 34-45 
    Details
    ISSN: 1435-5663
    Keywords: Automative design ; Information management ; Layout design ; Object oriented data base
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract During the layout design process, the spatial arrangement of components in an engineering system is developed in order to meet design goals and constraints. Proper organization of the information involved in this process enhances the quality of layout designs. The organization of information is accomplished through the use of the techniques and methods existing in the information management field. Using the object-oriented technique, a method was developed to guide the design of information management systems that support the layout design process. The method was developed in a case study involving, the layout design of automobile engine bay compoenents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01200260
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The design and implementation of a relational materials property data base (1988)
    Springer
    Engineering with computers 4 (1988), S. 87-97 
    Details
    ISSN: 1435-5663
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The choice of the proper material for a specific design is a critical issue not only from a materials property standpoint, but also from manufacturing, availability, and cost standpoints. Functions such as design, engineering analysis, manufacturing, and testing share in the production and use of this common data. A centrally located, computerized data base will provide the needed accessibility and flexibility to serve these groups. The flow of materials property data between the various engineering functions in a large manufacturer was studied and analyzed. A relational materials property data base was designed, implemented, and demonstrated. The relational model was chosen because it was the only one that could serve the diverse engineering functions with the plethora of information and still provide the flexibility and reasonable retrieval times required. The materials information necessary for all of these engineering functions and the resulting data dependencies were modeled using rigorous dependency diagrams and tables. This method allows the true qualities of and relationships between the data to be modeled, not just a description of the data flow. A relational data base was then developed using the Ingres data base management system (DBMS). Applications were also developed using Ingres, which provide the design engineers with an intelligent way to access the data base.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01201475
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A framework for feature-based representation of the design process (1990)
    Springer
    Engineering with computers 6 (1990), S. 185-192 
    Details
    ISSN: 1435-5663
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The design process is very complicated and differs with each engineer. The development of computer-based aids for design must take this into consideration and allow for the nuances of the individual. A generic representation of the information used in design is required for the development of any data base that supports the design aid. A properly designed data base or set of data bases can help aid. A properly designed data base or set of data bases can help integrate CAD, expert system, and ancillary programs, thereby forming an intelligent design system. A model has been developed that allows the information requirements of the design process to be analyzed. A data base for an intelligent design system can be developed based on these results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01200316
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The nucleation of microcellular thermoplastic foam with additives: Part I: Theoretical considerations (1987)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 485-492 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Microcellular foam is a polymeric foam with bubble sizes of 10 microns or less that is produced by saturating a polymer with gas and then utilizing the thermodynamic instabilities that result when the polymer is heated and the pressure is reduced to nucleate the cells. A model for the nucleation of microcellular foam in amorphous polymers with additives has been developed. The nucleation process depends on the solubility, concentration, and interfacial energy of any additives present. At very low levels, additives in solution act to increase the free volume of the polymer, resulting in homogeneous nucleation within the free volume Well above the solubility limit, heterogeneous nucleation dominates, as it lowers the activation energy for nucleation to levels below that for homogeneous nucleation. In the vicinity of the solubility limit of the additive, these two nucleation mechanisms compete. The polystyrene-zinc stearate system has been chosen for experimental evaluation.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760270702
    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...