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  • 1
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 583-585 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We present a novel heterostructure that exhibits large electroabsorption and refraction. The structure is periodic with a stackable building block, thus it allows large contrast and waveguide operation. The mechanism used is the quenching of absorption produced by transfer of electrons from a reservoir into a quantum well. We demonstrate the principle by presenting differential absorption and refraction spectra on a ten-period device.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 685-687 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The switching dynamics of photothermal-induced absorption optical bistability is studied in CdS. The bistable element being held near its switching threshold is switched by a pulse of an excimer laser, which can be regarded as δ shaped in time with respect to the thermal relaxation time of the sample. The dynamics of the switching process is influenced by the transverse relaxation of the temperature in the sample. Under appropriate conditions either a slowing down or a fast switching is observed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 342-344 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: 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.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1434-6036
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract In contrast to a dispersive nonlinearity, induced absorption may without a cavity lead to intrinsic optical bistability. If however such an absorber is placed in a ring-cavity with a round trip time larger than the relaxation time constant of the medium, oscillatory instabilities have been (theoretically) predicted. We investigate CdS at room temperature (photo-thermal effects) in a hybrid ring-cavity. A Farey-tree structure of the oscillation period as a function of the incident intensity is observed. In the present paper we discuss the influence an external modulation of the incident intensity has on the oscillation modes both, experimentally and with simple model calculations. Again a Farey-tree structure of the average period of the oscillation modes in multiples of the modulation period is obtained both as a function of the modulation frequency and the modulation amplitude.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Surgical endoscopy and other interventional techniques 1 (1987), S. 169-174 
    ISSN: 1432-2218
    Schlagwort(e): Acute colonic pseudo-obstruction ; Ogilvie's syndrome ; Colonoscopic decompression ; Cecostomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In addition to the presentation of 14 of our own patients, this study analyzes 1027 cases with acute colonic pseudo-obstruction reported in the literature from 1948 to 1987. Principal associated diseases are cardiopulmonary insufficiencies, postoperative conditions, and systemic disorders. The syndrome is related to a disturbance of colonic autonomic innervation resulting in gross dilatation of the cecum and the right hemicolon. Therapeutic measures include conservative management, colonoscopic decompression, and surgical procedures. The latter have been associated with high morbidity and mortality. Our data support a nonoperative approach to this condition, including conservative measures and colonscopic decompression as the initial therapy of choice with few complications and high efficacy.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 372 (1987), S. 845-846 
    ISSN: 1435-2451
    Schlagwort(e): Intrathoracic stomach ; 24 h pH measurement ; Gastric drainage ; Intrathorakaler Magen ; 24 h pH-Metrie ; Drainageoperation des Magens
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 11 Patienten mit einer distalen Resektion des Oesophagus und einer Oesophagogastrostomie in Höhe der Trachealbifurkation (n = 5) und einer transabdominalen subtotalen Oesophagektomie ohne Thoracotomie (n = 6) wurden untersucht. Es wurden keine Drainageoperationen ausgeführt. 6 Patienten hatten ein Plattenepithel-, 3 ein Adenocarcinom des Oesophagus, 2 ein Kardiacarcinom. Die Patienten wurden endoskopisch bis zu 8mal untersucht, jeder Patient hatte mindestens ein postop. CT, 4 Patienten wurden 24 h pH-metriert. 7 Patienten hatten eine Oesophagitis, 5 eine Gastritis. Obwohl die Mehrzahl der Patienten Speisereste im Magen zeigte, wurde bei keinem tumorfreien Patienten eine Magenausgangsstenose beobachtet. Eine primäre Drainageoperation des Magens halten wir daher für nicht indiziert.
    Notizen: Summary Eleven patients with distal resection of the esophagus and esophagogastrostomy at the level of the tracheal bifurcation (n = 5), as well as transhiatal esophagectomy without thoracotomy (n = 6), were studied. No drainage procedures were carried out. Three patients had an adenocarcinoma and 6 squamous cell carcinoma of the esophagus. Two patients presented with carcinoma of the cardia. The patients were examined endoscopically up to 8 times. In each patient at least one postoperative CAT scan was carried out; pH was measured for 24 h in 4 patients. Seven had esophagitis and 5 had gastritis of various degrees. Although the majority of the patients had food remains in the stomach, no gastric outlet stenosis was observed. Thus a primary gastric drainage operation is not necessary.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Langenbeck's archives of surgery 369 (1986), S. 743-743 
    ISSN: 1435-2451
    Schlagwort(e): Colonoscopy ; Acute intestinal bleeding ; Ileus ; Acute pseudo-obstruction ; Coloskopie ; Akute untere Intestinalblutung ; Ileus ; Akute Pseudoobstruktion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung In 5 Jahren wurden von 1565 Coloskopien 30 (1,9%) notfallmäßig durchgeführt. Bei 7 von 13 Patienten mit akuter Intestinalblutung war eine Lokalisation ohne Segmentzuordnung im Colon möglich. Bei 13 von 17 Patienten mit klinischen und radiologischen Zeichen eines Dickdarmileus ergab sich durch den endoskopischen Ausschluß eines mechanischen Hindernisses die Diagnose einer akuten Pseudoobstruktion. 12 dieser meist polymorbiden Patienten konnten durch die gleichzeitige endoskopische Dekompression risikoarm und erfolgreich therapiert werden. Bei strenger Indikationsstellung war die Notfallcoloskopie eine Hilfe sowohl für die OP-Indikaton wie für den OP-Zeitpunkt und das intraoperative Vorgehen.
    Notizen: Summary In 5 years, 30 of 1565 colonoscopies (1.9%) were performed as emergency procedures. In 7 of 13 patients with acute intestinal bleeding, localization to the colon without determination of the segment was possible. In 13 of 17 patients with clinical and radiological signs of colonic ileus, the diagnosis of acute pseudo-obstruction was established endoscopically by ruling out mechanical obstruction. Of these morbidly ill patients, 12 could be safely treated by endoscopic decompression with success. With a strict indication for surgery emergency colonoscopy was a great aid to determining both the indication for and the time of operation, as well as the intra-operative procedure.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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