Relaxation charge anomalies in the charge–voltage characteristics of alternating-current thin-film electroluminescent devices

Anomalous charge-voltage (Q-V) characteristics are observed for several types of alternating-current thin-film electroluminescent (ACTFEL) devices. These Q-V curves are anomalous because conduction charge flows in these devices exclusively during the portion of the wave form in which the applied voltage is constant, at its maximum value; this kind of conduction charge is denoted relaxation charge. In a normal ACTFEL device, most of the conduction charge flows during the portion of the wave form in which the applied voltage increases with time. The anomalous Q-V characteristics are attributed to insulator leakage for the devices tested. Simulation shows that such anomalous behavior may arise from either insulator of phosphor leakage

Vacuum ultraviolet reflectivity measurements of thin-film electroluminescent phosphors

Vacuum ultraviolet reflectivity measurements of three thin-film electroluminescent phosphors, zinc sulfide (ZnS), strontium sulfide (SrS), and strontium-calcium thiogallate (Sr₀.₄₅Ca₀.₅₅Ga₂S₄), are reported using thin-film samples. Measured ZnS reflectivity peak positions are in agreement with values previously reported in the literature. SrS room temperature reflectivity measurements are found to be consistent with previously reported low temperature measurements. Reflectivity measurements of Sr₀.₄₅Ca₀.₅₅Ga₂S₄ are reported for the first time; the reflectivity spectrum is found to rise monotonically above the band gap and to exhibit almost no structure, except for a small shoulder at ~6.8 eV and a single, broad peak at ~8.5 eV. The unusual nature of the Sr₀.₄₅Ca₀.₅₅Ga₂S₄ reflectivity spectrum is attributed to positional disorder in the stoichiometric thiogallate film

Informationstechnik - Ausweg aus der Unterentwicklung?: Kann die Informations- und Kommunikationstechnik die Entwicklung der Dritten Welt foerdern? Eroerterung dieser Frage fuer Lateinamerika unter besonderer Beruecksichtigung von Brasilien und Chile

Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, D-21400 Kiel C 202966 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Vestibular function in the space environment

Adaptation to the weightless state and readaptation after space flight to the 1-G environment on the ground are accompanied by various transitory symptoms of vestibular instability, kinetosis, and illusory sensations. Aside from the problem of how to treat and if possible prevent such symptoms, they offer a clue to a better understanding of normal vestibular functions. Weightlessness is a powerful new "tool" of vestibular research.Graybiel reported as early as 1952 that human subjects observed the illusion that a real target and the visual afterimage seemed to raise in the visual field during centrifugation when the subjects were looking toward the axis of rotation (oculogravic illusion). In aircraft parabolic-flight weightlessness, human subjects observed that fixed real targets appeared to have moved downward while visual afterimages appeared to have moved upward (oculoagravic illusion).It can be shown by electronystagmography as well as by a method employing double afterimages that part of this illusion is caused by eye movements that are triggered by the changing input from the otolith system. Another part of the illusion is based on a change of the subjective horizontal and must be caused by convergence of vestibular and visual impulses "behind" the eyes. This part was measured independently of the first one by using a new method. Eye movements could be prevented during these experiments by optical fixation with the right eye on a target at the end of a 24-in. long tube which was rigidly attached parallel to the longitudinal axis of an aircraft. At the same time the subject tried to line up a shorter tube, which was pivoting around his left eye, with the subjective horizon.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22156/1/0000587.pd