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
    The Role of Panicum virgatum (Switch Grass) in the Revegetation of Iron-Mine Tailings in Northern New York (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Restoration ecology 3 (1995), S. 0 
    Details
    ISSN: 1526-100X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We investigated the role of artificially introduced Panicum virgatum (switch grass) on the sequential natural revegetation of 15- and 35-year-old tailings in the Adirondack region of northern New York. Switch grass covered approximately 48% of the 15-year-old Chaumont Tailings. Establishment of switch-grass stands improved the fertility of the site by adding organic matter, raising pH, and elevating cation exchange capacity and concentrations of major nutrients (N, P, and K). Switch-grass stands also aided the initial recruitment of such pioneer species as Populus spp. (aspens), Salix spp. (willows), and Betula spp. (birches). This facilitation of recruitment of woody species is explained as follows: (1) robust switch-grass stands physically captured the wind-disseminated seeds of these species; (2) switch grass acted as a “nurse crop” for these species, thus these species were able to increase their density vigorously through root or stem sprouting; (3) a combination of both. Switch grass decreased its cover (14%), however, as observed in the 35-year-old South Tailings. As switch grass declined, such vigorous “root-suckering” species as aspens increased in dominance, followed by the invasion of Prunus pensylvanica (pin cherry).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1526-100X.1995.tb00085.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Experimental Restoration of Native Vegetation in Indiana Dunes National Lakeshore (1998)
    Cambridge, MA, USA : Blackwell Publishing Inc
    Restoration ecology 6 (1998), S. 0 
    Details
    ISSN: 1526-100X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We investigated the effects of prescribed fire, herbicide treatment, and sod removal on the eradication of exotic grasses and the establishment of native plant species in 24 experimental restoration plots in three razed residential sites within the boundary of Indiana Dunes National Lakeshore. During 1992–1995, herbicide treatment and sod removal decreased the combined cover of Poa pratensis (Kentucky blue grass) and Agropyron repens (quackgrass) significantly (from 82% to 13%, and 85% to 8%, respectively), whereas fire did not suppress such exotic lawn grasses. In 1993, several opportunistic species, represented by Cyperus spp. (umbrella sedges), Digitaria sanguinalis (crab grass), and Ambrosia artemisiifolia (common ragweed), filled the gaps left by the removal of lawn grasses. For the same period, Detrended Correspondence Analysis revealed a clear vegetation divergence between the control-fire plots and the herbicide-sod removal plots. While Poa pratensis and Agropyron repens continued to dominate the control and fire plots, the planted native species, represented by Schizachyrium scoparium (little blue-stem), Sorghastrum nutans (Indian grass), Rudbeckia hirta (black-eyed Susan), and Monarda punctata (horsemint), began to dominate in the herbicide and sod removal plots from 1994. In both herbicide and sod removal plots, the ground cover of grasses (68%) was much higher than the forbs (10%). The herbicide plots, where exotic species were removed but nitrogen-rich top soils were not removed, showed a higher diversity of planted native species than the sod removal plots (where both exotic species and top soils were removed) and the control-fire plots (where neither was removed). This finding suggests that an optimum but not excessive concentration of soil nitrogen is needed to support a maximum species diversity in such infertile substrate as sandy soil. In addition, the decrease in potassium in all plots, regardless of treatment, suggests that potassium may become a limiting factor for our restored native vegetation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1526-100x.1998.06114.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Evaluating the effects of optical and carrier losses in etched-post vertical cavity lasers (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 5871-5875 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We demonstrate the combined effects of optical scattering loss and surface recombination (or carrier diffusion) on the performance and scalability of etched-post vertical cavity lasers (VCLs). The size dependence of optical losses and threshold gain are determined from pulsed measurements of external quantum efficiency. Deeper etch depths result in a stronger radial dependence of the threshold gain, which quickly increases the threshold current density. With optical loss accounted for, pulsed threshold current density measurements give the extra information needed for evaluating carrier loss. Surface recombination or carrier diffusion also results in threshold current density increases, but scalability is ultimately limited by the ability of the active region to provide enough gain for smaller size, higher optical loss devices. Even with these losses, three-quantum-well VCLs with shallow etches have threshold currents as low as 420 μA. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360588
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Antimonides with the half-Heusler structure: New thermoelectric materials (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 1415-1417 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The thermoelectric properties near ambient temperature of half-Heusler alloys based on LnPdSb, where Ln=Ho, Er, and Dy are reported. The Seebeck coefficients are large, between 60 and 250 μV/K, and the materials are p type. The resistivities are between 0.6 and 20 mΩ cm. Thermal conductivities are between approximately 5.0 and 3.5 W/mK at 300 K, and are smallest in intentionally disordered materials. The highest ambient temperature ZT obtained is 0.06. Band-structure calculations are presented for LuPdSb. It is suggested that half-Heusler alloys with 18 electrons per formula unit may represent a large class of thermoelectric materials. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123596
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Near-field scanning optical spectroscopy of an InGaN quantum well (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 72 (1998), S. 927-929 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Near-field scanning optical microscopy is used to image photoluminescence (PL) in an InGaN/GaN quantum well (QW) with spatial resolution of approximately 100 nm for temperatures between 50 and 295 K. Strong (∼50%) fluctuations in the quantum well photoluminescence as well as a tenfold enhancement of deep level-related emission at lower energies occur at large (∼500 nm diam) pits in the heterostructure. Regions of smaller (∼15%) fluctuations in the QW PL are not correlated with the presence of pits. The spectrum of the QW PL shows no significant variations on the length scales probed in this experiment. We thus find no spectroscopic signature of the recombination of strongly localized carriers at temperatures above 50 K. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120875
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Many body effects in the temperature dependence of threshold in a vertical-cavity surface-emitting laser (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 2460-2462 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependence of the threshold in a vertical-cavity surface-emitting laser is investigated. Comparison of theory with experiment indicates that many-body Coulomb interactions play an important role. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113995
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    High-power mode-locked semiconductor lasers using flared waveguides (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 3558-3560 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We describe the use of flared waveguide diode lasers for obtaining increased output power under mode-locked operation. The flared waveguide expands the optical mode from a narrow region which gives a single lateral optical mode, to a wider multimode region for higher pulse saturation energy. Flared gain and flared absorber section geometry devices are compared to devices with conventional uniform waveguides. Using flared gain section devices, improvements in both pulse energy (6.8 pJ) and pulsewidth (3.3 ps) were measured compared to uniform waveguide devices. Peak powers of over 2 W are obtained, which, to our knowledge, is the highest peak power obtained directly from mode-locked single stripe diode lasers. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113786
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Temperature-dependent threshold and modulation characteristics in InGaAs/GaAs quantum-well ridge-waveguide lasers (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 2040-2042 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The observed temperature dependence of threshold currents in InGaAs/GaAs quantum-well ridge-waveguide lasers is modeled. This method incorporates both experimental data and theoretical gain calculations. The results show that lateral leakage currents must be included in the ridge-waveguide laser models. Based on the same model, the temperature-dependent modulation characteristics for InGaAs/GaAs quantum-well ridge-waveguide lasers are also investigated. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113685
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Near-field scanning optical microscopy of indium gallium nitride multiple-quantum-well laser diodes (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 2349-2351 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Near-field scanning optical microscopy is used to image electroluminescence from three and ten quantum-well (QW) indium gallium nitride based laser diodes. Facet cross sections are imaged with a spatial resolution of 〈100 nm, below and above the lasing threshold. Observation of spatially resolved spectra near the active region reveals compositional fluctuations as well as absorption and reemission of the lasing mode. Single-mode emission is observed for narrow (3 and 5 μm wide) 3 QW laser bars. Near-field measurements show a relationship between modal emission, waveguide structure, and lateral device size. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123847
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Ln3Au3Sb4: Thermoelectrics with low thermal conductivity (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 3999-4001 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The thermoelectric properties of intermetallic compounds with the Y3Au3Sb4 structure type, of formula Ln3Au3Sb4 for Ln=Gd, Nd, Ho, and Sm, are reported. The highest Seebeck coefficients are on the order of 100–200 μV/K, indicating that the dominant carriers are holes, and increase with increasing temperature. Variation of the Au:Sb ratio significantly affects the resistivities and Seebeck coefficients. Materials with mixtures of lanthanides on the large atom site show improved Seebeck coefficients without degradation of the electrical resistivity. The thermal conductivities are very low, even for the stoichiometric materials, and decrease in materials with mixed lanthanides. Band-structure calculations show a complex multivalley character for both valence and conduction bands. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123240
    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...