ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    Silver on diamond Schottky diodes formed on boron doped hot-filament chemical vapor deposited polycrystalline diamond films (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 61 (1992), S. 1119-1121 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Schottky diodes were fabricated using sputter deposited silver contacts to boron doped polycrystalline diamond thin films grown by a hot-filament chemical vapor deposition process with trimethyl borate as an in situ dopant source. High forward current density and a high forward-to-reverse current ratio were exhibited by these diodes. Current density-voltage and capacitance-voltage-frequency characteristics of these diodes are very similar to those of Schottky diodes fabricated using a single-crystal diamond substrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.107687
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Precise Real-Time Positioning in WADGPS Networks (2000)
    Springer
    GPS solutions 4 (2000), S. 68-75 
    Details
    ISSN: 1521-1886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Notes: In recent years the importance of real-time positioning and navigation with the Global Positioning System (GPS) has grown rapidly. Starting from the establishment of differential GPS (DGPS) reference stations for marine and land navigation, new users and applications have emerged that resulted in a high demand for the establishment of a high-density network of reference stations around the world. Many countries have established their own DGPS service, which is either governmentally or commercially owned. These services are referred to as Local Area DGPS Systems (LADGPS). However, the costs for the establishment and maintenance of a dense network of reference stations are very high. Therefore Wide Area DGPS Systems (WADGPS) are being developed to overcome the main drawbacks of LADGPS. In this case, only a few reference stations are used to cover a large area, such s a continent like Europe. To achieve high positioning accuracies, real-time modeling of the main error sources for long-range baselines is required as errors in the satellite orbit and ionospheric refraction do not cancel entirely in double differencing. In this article, a real-time correction model based on the Kalman filter for WADGPS and networked LADGPS services is discussed and results of field tests in a WADGPS network in Europe are presented. © 2000 John Wiley & Sons, Inc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00012844
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Effects of bond coat preoxidation on the properties of ZrO2-8wt.% Y2O3/Ni-22Cr-10Al-1Y thermal-barrier coatings (1991)
    Springer
    Oxidation of metals 36 (1991), S. 221-238 
    Details
    ISSN: 1573-4889
    Keywords: thermal-barrier coatings ; preoxidized Ni-Cr-Al-Y bond coat ; thermal-cyclic oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Plasma-sprayed thermal barrier coatings (TBCs) consist of an intermediate MCrAlY bond coat to protect the substrate superalloy from oxidation/hot corrosion and a thermal insulating zirconia-based ceramic top coat. This system is developed for advanced turbine-engine, hot-section components. In this study the as-sprayed Ni-22Cr-10Al-1Y bond coat was subjected to preoxidation treatment at 1000° C for 1, 50, 100, and 200 hr, also at 1100°C, 1200°C and 1300°C for 1 hr to form an oxide scale before subsequent deposition of a ZrO2-8wt.% Y2O3 top coat. The oxidation kinetics were measured, and the phase constitution and morphology of pregrown oxides on the Ni-22Cr-1Y bond coat were analyzed by x-ray diffractometer and SEM/EDS to elucidate the improvement and degradation mechanisms of the new system. The results of the experiments in this study showed that the tentative ZrO2-8wt.% Y2O3 TBC specimens with preoxidized Ni-22Cr-10Al-1Y bond coat, when properly processed, exhibited lower oxidation rates and generally longer lifetime compared with traditional TBC specimens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00662963
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The spalling modes and degradation mechanism of ZrO2-8 wt.% Y2O3/CVD-Al2O3/Ni-22Cr-10Al-1Y thermal-barrier coatings (1993)
    Springer
    Oxidation of metals 40 (1993), S. 465-481 
    Details
    ISSN: 1573-4889
    Keywords: thermal-barrier coatings (TBCs) ; CVD-Al2O3 ; bond coat ; thermal-cyclic oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract State-of-the-art conventional thermal-barrier coatings consist of a thermalinsulating, partially-stabilized ZrO2 top coat and a bond coat. In this study, a continuous alumina-diffusion-barrier layer was deposited and interposed between the top coat and bond coat by chemical-vapor deposition (CVD). Both the conventional and the experimental TBC systems were cyclically tested at 1000°C, 1050°C, 1100°C, and 1150°C to evaluate and compare oxidation, performance, and fracture behavior. Introduction of the intermediate CVD-Al2O3 layer effectively suppressed the oxidation rate of the bond coat and sufficiently altered its oxidation behavior. The thermal-cyclic life of TBCs was improved by the new system. The failure of the ZrO2-8 wt.% Y2O3/CVD-Al2O3/Ni-22Cr-10Al-1Y TBC specimens was observed to propagate mainly along the lamellar splats of the top coat, and secondarily along the top coat/CVD-Al2O3 interface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00666387
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Effect of pre-aluminization on the properties of ZrO2-8wt.% Y2O3/Co-29Cr-6Al-1Y thermal-barrier coatings (1992)
    Springer
    Oxidation of metals 38 (1992), S. 99-124 
    Details
    ISSN: 1573-4889
    Keywords: thermal-barrier coatings ; pre-aluminized Co-Cr-Al-Y bond coat ; thermal-cyclic oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Specimens of investment-cast Mar-M247 superalloy were vacuum-plasma sprayed with Co-29Cr-6Al-1Y bond coat, and part of the specimens were further pre-aluminized at 980°C for 2, 4, 6, 8, and 10 hours. All the specimens were then deposited with ZrO2-8 wt.% Y2O3 thermal-barrier coatings (TBCs) and thermally cycled at 1050°C to evaluate the effect of time of the prealuminizing treatment on the performance and failure mechanism of the modified system. Results showed that TBC specimens with pre-aluminized bond coatings exhibited lower oxidation rates and significantly higher cyclic life when compared with unaluminized specimens. The failure of bond-coat pre-aluminized TBC specimens was observed to propagate mainly along the lamellar splats of the top coat, whereas the failure of conventional TBC specimens occurred mainly along the top-coat/spinel oxides interface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00665047
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Effect of bond-coat pre-aluminization and pre-oxidation duplex pretreatment on the performance of ZrO2-8 wt.% Y2O3/Co-29Cr-6Al-1Y thermal-barrier coatings (1993)
    Springer
    Oxidation of metals 40 (1993), S. 229-243 
    Details
    ISSN: 1573-4889
    Keywords: thermal-barrier coatings ; pre-aluminization and pre-oxidation ; Co-29Cr-6Al-1Y bond coat ; thermal-cyclic oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A modification to the conventional thermal-barrier coating (TBC) system was made. In this study, the low-pressure, plasma-sprayed Co-29Cr-6Al-1Y bond coat received a duplex pretreatment of bond-coat pre-aluminizing and pre-oxidation prior to overlaying the air-plasma sprayed ZrO2-8 wt.% Y2O3 top coat. The effects of this treatment on the properties of the TBC system were evaluated by thermal-cyclic test at 1050° C in air. The results of cyclic-oxidation tests showed that the proposed processes could remarkably improve the performance of ZrO2-8 wt.% Y2O3/Co-29Cr-6Al-1Y TBC. The improvement was attributed to a modification of bond-coat oxides and the associated reduction of the oxidation rate of the MCrAlY bond coat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00664492
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Ultrasonic spray pyrolysis of a chelated precursor into spherical YBa2Cu3O7−x high temperature superconductor powders (1995)
    Springer
    Journal of materials science 30 (1995), S. 6136-6144 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract YBa2Cu3O7−x powders have been prepared directly by ultrasonic spray pyrolysis using nitrate salts as precursors and citric acid and ethylene glycol as chelating agents. This method consists of ultrasonically atomizing a precursor solution into droplets, thermally chelating, drying, decomposing and solid state reacting these droplets in a carrier gas flowing through a tube furnace, forming a well characterized powder. The chelated precursor adjusted to pH 8 forms bidentate bonding between the cations and the chelating agents. Thermal analysis and infrared spectroscopy identify the decomposition steps of the precursor. The dry gel of the chelated precursor is nearly amorphous indicating intimate mixing on the atomic level. X-ray diffraction suggests the mechanism of forming the 1∶2∶3 crystalline phase. Spherical powders are produced with diameters ranging from 0.2 to 0.8 μm depending on the ultrasonic frequency and the solution concentration. The spherical particles are hollow or solid depending on the precursor type and the furnace temperature. The primary crystallite size is about 10–50 nm. X-ray diffraction data and infrared spectra show that the spray pyrolysed powder from the chelating precursor forms the YBa2Cu3O7−x phase at 800 °C, which is 100 °C lower than that formed from unchelated precursors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369659
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A necessary and sufficient condition in Lyapunov robust control (1989)
    Springer
    Journal of optimization theory and applications 63 (1989), S. 191-204 
    Details
    ISSN: 1573-2878
    Keywords: Robust control ; uncertain systems ; Lyapunov's method ; necessary and sufficient conditions ; controllable companion forms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We consider Lyapunov's equationPA+A T P+Q=0, whereQ is symmetric positive definite andA is in controllable companion form. We prove that a necessary and sufficient condition thatA be stable is that the first rowP 1 of theP-matrix be a stablen−1 coefficient vector. This result is related to the minimum phase property of linear systems and is useful in designing robust controllers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00939573
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Necessary and sufficient condition in Lyapunov robust control: Multi-input case (1990)
    Springer
    Journal of optimization theory and applications 66 (1990), S. 1-21 
    Details
    ISSN: 1573-2878
    Keywords: Robust control ; uncertain systems ; Lyapunov's method ; linear control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We consider a linear time-invariant finite-dimensional system x=Ax+Bu with multi-inputu, in which the matricesA andB are in canonical controller form. We assume that the system is controllable andB has rankm. We study the Lyapunov equationPA+A T P+Q=0, withQ〉0, and investigate the properties thatP must satisfy in order that the canonical controller matrixA be Hurwitz. We show that, for the matrixA being Hurwitz, it is necessary and sufficient thatB T PB〉0 and that the determinant ofB T PW be Hurwitz, whereW=block diag[w 1,...,w m ], with elementw i =[s k i −1,s k i −2,...,s, 1] T ; here, the symbolsk i ,i=1, 2, ...,m, denote the Kronecker invariants with respect to the pair {A, B}. This result has application in designing robust controllers for linear uncertain systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00940529
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    On the robustness of linear stabilizing feedback control for linear uncertain systems (1989)
    Springer
    Journal of optimization theory and applications 63 (1989), S. 205-212 
    Details
    ISSN: 1573-2878
    Keywords: Robust control ; uncertain systems ; Lyapunov's method ; linear stabilizing control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We investigate linear time-invariant scalar-input systems with constant uncertainties that are not required to satisfy matching conditions. In a previous paper, the existence of stabilizing discontinuous controllers is established under three assumptions for such systems. The first assumption requires controllability of the system for each uncertainty. The second is a condition on an uncertain Lyapunov equation, and the third is a boundedness condition related to the controllability matrix. In this paper, using the same assumptions, we show the existence of a linear stabilizing control. Our result is related to the high-gain theorem of classical control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00939574
    Location Call Number Expected 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...