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  • 1
    Electronic Resource
    Electronic Resource
    The physical origin of gauge invariance in electrodynamics (1999)
    Springer
    Electrical engineering 81 (1999), S. 363-367 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Der physikalische Ursprung der Eichinvarianz der Maxwellschen Theorie liegt in der Quantenphysik begründet und kann daher nicht im Rahmen der klassischen Elektrodynamik erklärt werden. Um diese Lücke zu schließen, geben wir eine fundamentale Beschreibung dieser Eichinvarianz, welche die physikalischen Ideen des modernen Verständnisses von Eichtheorien zusammenstellt. Unsere Darstellung macht auch dem Elektroingenieur dieses fortgeschrittene Wissen zugänglich.
    Notes: Contents The physical origin of gauge invariance in Maxwell's theory is rooted in quantum physics and thus not approachable from classical electrodynamics. In order to bridge this gap we provide a fundamental description of gauge invariance in electrodynamics which puts together the physical ideas behind the modern understanding of gauge theories. Our presentation makes this advanced knowledge accessible to the Electrical Engineer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002020050062
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Exact analytical solution for nonuniform multiconductor transmission lines with the aid of the solution of a corresponding matrix Riccati equation (1998)
    Springer
    Electrical engineering 81 (1998), S. 117-120 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Die Telegraphengleichungen für ungleichförmige Vielfachleiter lassen sich als Differentialgleichungen erster Ordnung in Supervektor-/Supermatrixform schreiben. Dazu müssen die Spannungs- und Stromvektoren zu einem neuen Vektor zusammengefaßt werden. Der Übergang auf Wellenvektoren führt auf eine Differentialgleichung derselben Form. Die Lösungen dieser zusammengefaßten Telegraphengleichungen lassen sich durch den Supermatrizanten ausdrücken. Eine Transformation mit einer elementaren Relativmatrix und das anschließende Lösen einer Matrix-Riccati-Gleichung vereinfachen die zu lösenden Telegraphengleichungen derart, daß der gesuchte Supermatrizant mit den üblichen Regeln für Produktintegrale gefunden werden kann. Dieser Supermatrizant setzt sich seinerseits im wesentlichen ausN×N-Matrizanten in seinen Matrixblöcken zusammen. Füreinen nicht-gleichförmigen Leiter und im Falle zyklischer Matrizen für die ungleichförmigen Vielfachleiter können die Supermatrizanten als Exponential-funktionen dargestellt werden.
    Notes: Contents Nonuniform multiconductor transmission lines (NMTLs) are formulated from the telegrapher equations into a first-order supervector/supermatrix differential equation combining the voltage and current vectors. This equation is converted to one for the waves propagating in the two directions of the transmission line. Both equations can be represented in a common general supermatrix form. The supermatrizant describing the solutions of this general equation is evaluated via transformation with an elementary relative matrix and the solution of a matrix Riccati equation simplifying the resulting telegrapher equations to a structure to which the usual sum rules for product integrals can be applied easily. The block elements of the supermatrizant are (mainly) composed by matrizants ofN×N matrices. For a single nonuniform line and for circulant NMTLs the supermatrizants are represented by exponentials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01237894
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Exact analytical solution for nonuniform multiconductor transmission lines with the aid of the solution of a corresponding matrix Riccati equation (1998)
    Springer
    Electrical engineering 81 (1998), S. 117-120 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Die Telegraphengleichungen für ungleichförmige Vielfachleiter lassen sich als Differentialgleichungen erster Ordnung in Supervektor-/Supermatrixform schreiben. Dazu müssen die Spannungs- und Stromvektoren zu einem neuen Vektor zusammengefaßt werden. Der Übergang auf Wellenvektoren führt auf eine Differentialgleichung derselben Form. Die Lösungen dieser zusammengefaßten Telegraphengleichungen lassen sich durch den Supermatrizanten ausdrücken. Eine Transformation mit einer elementaren Relativmatrix und das anschließende Lösen einer Matrix-Riccati-Gleichung vereinfachen die zu lösenden Telegraphengleichungen derart, daß der gesuchte Supermatrizant mit den üblichen Regeln für Produktintegrale gefunden werden kann. Dieser Supermatrizant setzt sich seinerseits im wesentlichen aus N×N-Matrizanten in seinen Matrixblöcken zusammen. Für einen nicht-gleichförmigen Leiter und im Falle zyklischer Matrizen für die ungleichförmigen Vielfachleiter können die Supermatrizanten als Exponentialfunktionen dargestellt werden.
    Notes: Contents Nonuniform multiconductor transmission lines (NMTLs) are formulated from the telegrapher equations into a first-order supervector/supermatrix differential equation combining the voltage and current vectors. This equation is converted to one for the waves propagating in the two directions of the transmission line. Both equations can be represented in a common general supermatrix form. The supermatrizant describing the solutions of this general equation is evaluated via transformation with an elementary relative matrix and the solution of a matrix Riccati equation simplifying the resulting telegrapher equations to a structure to which the usual sum rules for product integrals can be applied easily. The block elements of the supermatrizant are (mainly) composed by matrizants of N×N matrices. For a single nonuniform line and for circulant NMTLs the supermatrizants are represented by exponentials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002020050030
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The physical origin of gauge invariance in electrodynamics (1999)
    Springer
    Electrical engineering 81 (1999), S. 363-367 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Der physikalische Ursprung der Eichinvarianz der Maxwellschen Theorie liegt in der Quantenphysik begründet und kann daher nicht im Rahmen der klassichen Elektrodynamik erklärt werden. Um diese Lücke zu schließen, geben wir eine fundamentale Beschreibung dieser Eichinvarianz, welche die physikalischen Ideen des modernen Verständnisses von Eichtheorien zusammenstellt. Unsere Darstellung macht auch dem Elektroingenieur dieses fortgeschrittene Wissen zugänglich.
    Notes: Contents The physical origin of gauge invariance in Maxwell's theory is rooted in quantum physics and thus not approachable from classical electrodynamics. In order to bridge this gap we provide a fundamental description of gauge invariance in electrodynamics which puts together the physical ideas behind the modern understanding of gauge theories. Our presentation makes this advanced knowledge accessible to the Electrical Engineer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01387156
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    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Kontraktionsablauf unter physiologischer und ventrikulärer Schrittmacherstimulation (1984)
    Springer
    Journal of molecular medicine 62 (1984), S. 1132-1135 
    Details
    ISSN: 1432-1440
    Keywords: Phase imaging ; Radionuclide ventriculography ; Ventricular pacing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Phase imaging of gated radionuclide ventriculography was applied to the identification of cardiac activation patterns in patients with sinus rhythm (n=14) or with ventricular (VVI)- (n=28), atrial (AAI)- (n=3) or AV-sequential (DDD)-pacing (n=17). In patients with sinus rhythm, AAI-or DDD-pacing, analysis revealed homogeneous distribution of phase across both ventricles. In VVI-pacing a left bundle branch block configuration of the ventricular activation was found in 21 of 28 patients. In 7 of 28 patients phase distribution indicated a simultaneous activation of both ventricles (with or without delimitation of the apex of the right ventricle). This is of clinical importance because artificial spread of excitation and asynchronous contraction during VVI-pacing may be responsible for higher myocardial oxygen demand. Retrograde conduction in VVI-pacing was found in 9 of 28 patients. Phase analysis provides a reliable method for evaluation of pacing-induced activation patterns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01782471
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Buchbesprechungen (1986)
    Springer
    Journal of molecular medicine 64 (1986), S. 805-805 
    Details
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01732193
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Zunahme des Leberblutflusses unter Nifedipin (1986)
    Springer
    Journal of molecular medicine 64 (1986), S. 1113-1118 
    Details
    ISSN: 1432-1440
    Keywords: Nifedipine ; Liver blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The hepatic hemodynamic effect of 20 mg sublingual nifedipine was evaluated in 15 patients (13 men, 2 women) during heart catheterization. The liver blood flow was measured 10 min after administration of nifedipine by continuous thermodilution (Baim coronary sinus flow analyzer). Nifedipine was associated with a decrease in systolic blood pressure (from 156+/−14 to 138+/−13 mmHg), an increase in heart rate from (73+/−13 to 81+/−8.6 beats/min), and increase in cardiac output (from 6.0+/−1.6 to 6.5+/−1.3 l/min). In 2/15 patients no significant change was derived. The liver blood flow increased in 13/15 patients from 218+/−171.7 to 336.7+/−247.7 ml/min (22%–194%,P〈0.01). The study demonstrates that the vasodilation of nifedipine involves the hepatic circulation. If the hepatic clearance of drugs is high and flow dependent, nifedipine-induced increase of hepatic blood flow may impair drug clearance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01726871
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Buchbesprechungen (1987)
    Springer
    Journal of molecular medicine 65 (1987), S. 1172-1172 
    Details
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01733253
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    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Buchbesprechungen (1985)
    Springer
    Journal of molecular medicine 63 (1985), S. 238-240 
    Details
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01731178
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    Erhöhtes atriales natriuretisches Peptid (ANP) bei essentieller Hypertonie — Abhängigkeit vom rechtsatrialen Druckverhalten (1989)
    Springer
    Journal of molecular medicine 67 (1989), S. 756-761 
    Details
    ISSN: 1432-1440
    Keywords: Atrial natriuretic peptide ; Hypertension ; Pulmonary resistance ; Pulmonary hypertension
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of atrial natriuretic peptide (ANP) in the pathogenesis of essential hypertension has not yet entirely been clarified. We investigated whether the increase of ANP in essential hypertension may be explained by elevated right atrial pressures and/or a different relationship between right atrial pressures and ANP secretion. Patients with stable essential hypertension undergoing right and left heart catheterization because of suspected coronary heart disease had significantly higher ANP levels than normotensives: 58.7±6.7 pg/ml in hypertensives versus 42.0±4.1 pg/ml in normotensives (p〈0,01). Matching hypertensives with normotensives at identical levels of left ventricular enddiastolic pressure revealed significantly higher mean pulmonary artery pressures in hypertensives. Right atrial diastolic pressure (v-wave) after matching for LVEDP was 4.8±0.5 mm Hg in hypertensives and 3.1±0.2 mm Hg in normotensives (p〈0.05). In addition, at any given mean right atrial pressure hypertensives showed higher ANP levels than normotensives. These results demonstrate that hypertensives exhibit raised pressures in the pulmonary artery independent of left ventricular pressure load. The elevation in right atrial pressures and the steeper relationship between these pressures and ANP are a suitable explanation for raised ANP levels in hypertension. ANP in essential hypertension may represent a counterregulation against elevated pulmonary resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01745345
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    Paper (German National Licenses)
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