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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 15 (1978), S. 393-397 
    ISSN: 1432-0630
    Keywords: 84 ; 85.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A high frequency transmission line periodically loaded with varactor diodes is presented to study nonlinear wave propagation. The nonlinearity and dispersion characteristics are experimentally and theoretically analysed. Experimental results on shock wave formation and harmonic frequency generation are found to be in good agreement with theoretical predictions. The influence of dispersion on second-harmonic frequency generation is particularly discussed yielding large values of the efficiency.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 16 (1978), S. 35-38 
    ISSN: 1432-0630
    Keywords: 84 ; 85.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Nonlinear dispersive wave propagation along a transmission line periodically loaded with varactor diodes is examined. Assuming small nonlinearity and weak dispersion the theoretical description may be reduced to the wellknown KdV equation. Accordingly, the presented measurements show how a sine-wave breaks up into a number of spikes and then recurs which therefore may be interpreted on the basis of soliton theory: Experimental results on soliton development and interaction are given and the recurrence phenomena of the Fermi-Pasta-Ulam problem are investigated. The measurements are found to be in good agreement with theoretical and numerical evaluations.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Herz-, Thorax- und Gefässchirurgie 13 (1999), S. 95-99 
    ISSN: 0930-9225
    Keywords: Schlüsselwörter Bypasschirurgie ; koronare Thrombendarteriektomie ; Langzeitergebnisse ; Key words Coronary surgery ; endarterectomy ; long-term results
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Coronary endarterectomy (EA=TEA) is an additive method in coronary revascularization. Although some surgeons report excellent results, most cardio-thoracic surgeons try to avoid it.  The aim of this study was to examine the clinical outcome of patients, in whom EA had been performed.  A questionnaire was sent to all patients and their physicians one year after the coronary TEA operation. Additionally, coronary angiographic studies were performed in patients with TEA of the LAD (LAD=RIVA). 86 patients (19 females and 67 males) were studied; mean age was 61 years. There were 29 TEA of the LAD and 57 TEA of the RCA. Thirty days mortality was 7% compared to 1.8% in elective patients without EA. Mortality after EA of the LAD was twice as high as after EA of the RCA. Perioperative infarction on the other hand was equal.  After one year, 45 patients were alive and doing well; 70% of the patients reached NYHAI. The LAD was, except for one case, restenosed. In 69% there was occlusion of the LAD, yet in most of the cases the patients were in NYHAI.  According to our study we would recommend avoidance of TEA, since it has a markedly higher incidence of perioperative infarct and mortality despite the use of anticoagulation, TEA of the LAD has a very high reocclusion rate.
    Notes: Zusammenfassung Die koronare Thrombendarteriektomie (TEA) stellt bei Patienten mit schwerer diffuser Dreigefäßerkrankung zusätzlich zur aortokoronaren Bypassanlage eine Möglichkeit der koronaren Revaskularisation dar und wird wegen hoher operativer Mortalität und Infarktraten in der Literatur unterschiedlich beurteilt.  86 Patienten (19 Frauen und 67 Männer) wurden im Rahmen einer koronaren Revaskularisationsoperation thrombendarteriektomiert. 29 TEA des Ramus interventricularis anterior (RIVA) und 57 TEA der rechten Koronararterie (Right coronary artery-RCA) wurden durchgeführt. Die 30-Tage-Mortalität war deutlich höher als nach koronarer Revaskularisation ohne TEA (7% vs. 1,8%).  Alle thrombendarteriektomierten Patienten (n=86) wurden nach 18 Monaten kardiologisch untersucht und in ausgewählten Fällen kontrollangiographiert.  45 Patienten lebten noch und befanden sich zu 70% im NYHA-Stadium1. Die Patienten nach TEA des RIVA zeigten bis auf eine Ausnahme erneute Stenosen oder Verschlüsse (70% der Patienten).  Aus unseren Ergebnissen läßt sich ableiten, daß die koronare Thrombendarteriektomie für den Patienten eine erhöhte perioperative Gefährdung darstellt, ohne die Durchgängigkeit des Gefäßes langfristig wiederherzustellen.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 168-169 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Hole-trap states in the gate oxide of a Si metal-oxide-semiconductor field-effect transistor (MOSFET) are investigated by inhomogeneous excimer laser irradiation. Subbandgap ultraviolet light photons with an energy exceeding a threshold lying between 5.5 and 6.4 eV were found to excite electrons from these originally neutral states into the SiO2 conduction band. A fixed positive charge is left behind. The degradation in MOSFET performance due to the irradiation is comparable to that accompanying hot-hole injection. Also, subsequent hot-electron stress changes the device characteristics in a way similar to hot-electron stress following hot-hole stress. It is concluded that the traps responsible for hot-carrier degradation cause the optically induced charge trapping.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of medicinal chemistry 3 (1960), S. 99-110 
    ISSN: 1520-4804
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 342-344 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We discuss the nonlinear characteristics of hybrid CdS devices at room temperature by using increasing absorption at a wavelength of 514.5 nm. Via the thermo-optical properties, a self-electro-optic effect occurs due to the optically induced dissipation of electrical power. As a special application, the device can be utilized as an electro-optic modulator for Ar+ laser light. In addition, voltage controlled optical bistability is also observed.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 1656-1659 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on experimental investigations of electro-optic polymers, carried out in connection with the development of a contactless measuring technique for electrical signals in printed circuit boards. We describe the preparation of the poled polymers and the measurement of the electro-optic properties. The polymer samples consist of poly methyl methacrylate doped with N,N-dihexyl-4-amino-4'-nitrostilbene (DHANS). For a sinusoidal electrical field with a frequency of 1.325 kHz applied to the polymer sample we observe a change of the refractive index linear in the electrical field, the poling field, and the DHANS concentration. Using a dc field, we obtain a considerably larger field-induced change of the refractive index which is quadratic in the field, linear in the DHANS concentration, and nearly independent of the poling field. For both cases a figure of merit is defined and experimentally determined. With the present experimental setup, a minimum detectable change of the refractive index requires an ac voltage amplitude of 85 V and a dc voltage of 20 V.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 110-112 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The existence of bistability, gap solitons, and self-localized solitons in a magnetostatic periodic structure are predicted. The very low threshold power necessary for the observation of such phenomenas at microwave frequencies makes these structures very attractive for microwave signal processing.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 105-107 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In semiconductor materials with S-shaped negative differential conductivity, pattern formation due to current filament formation is observed. We present experimental results of filamentation in Si p-i-n diodes and propose an equivalent circuit to describe the observed structures. The electrical circuit is based upon numerical results of electrical field−current density characteristics in p-i-n diodes. From this model we derive an equation, which describes the current density distribution in the device as a solitary structure. The proposed analytical solution, which is well known from the theory of pulse propagation in nerve fibers, leads to expressions for the peak current density and the width of a filament.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 97 (1989), S. 0 
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Palaeomagnetic data have been obtained from Plio-Pleistocene rocks of the Indian Heaven volcanic field (IHVF) located in the High Cascade province in southern Washington. Alternating field demagnetization yielded well-defined directions from 56 individual lava flows (sites) from 23 volcanic units. All units sampled were normally magnetized suggesting that volcanic activity within the Indian Heaven region occurred primarily during the last 0.73 Myr and not over the last 3.75 Myr as suggested by K-Ar ages. Combining palaeomagnetically similar site mean directions from lava flows from the same volcanic unit resulted in N= 35. the mean direction calculated from this data set is I= 65.2° and D = 0.2° (095 = 3.3°; k = 56.4) while the palaeomagnetic pole [calculated using virtual geomagnetic pole (VGP) data] is located at 87.7°N, 231.4°E (or95 = 4.7; k= 27.2). This pole is not significantly different from the pole determined from all data (N= 56) or the rotational axis and is slightly near-sided with respect to the mean sampling site longitude. the between-site angular dispersion of the VGPs about the mean for N-35 and N= 56, although low, is not statistically different at the 95% confidence level from the expected value predicted by model F of McFadden & McElhinny (1984). Our data, together with other recent data from the western United States, do not confirm the presence of a persistent standing non-dipole field component in this region during the Plio-Pleistocene as suggested by Brown & Mertzman (1979). Additionally, these data suggest that VGP angular dispersion associated with the geomagnetic field has been decreasing over the last 5 Myr.
    Type of Medium: Electronic Resource
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