Surface charge accumulation and decay on a spacer stressed with DC voltages at atmospheric conditions

Contents Surface charge accumulation and its decay at a GIS spacer are studied at atmospheric conditions employing a two step-calibration method. The results show that the accumulation saturates within 30 minutes; the dominant mechanism of surface charge accumulation is the drift of charged particles via air, while that of the decay is surface conduction. The characteristics are similar at both polarities.

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Sättigungskonzentration und Abklingverhalten der Oberflächenladung an einem mit Gleichspannung beanspruchten Abstandshalter unter atmosphärischen Bedingungen

Übersicht Die Konzentration und das Abklingen von Oberflächenladungen an einem GIS Abstandshalter wurden unter atmosphärischen Bedingungen mit Hilfe eines zweistufigen Kalibrierungsverfahrens untersucht. Die Ergebnisse zeigen eine Sättigung der Ladungskonzentration innerhalb von 30 Minuten. Als Hauptursache der Ladungskonzentration ist die Drift geladener Teilchen in Luft anzusehen, während das Abklingen auf die Oberflächenleitung zurückzuführen ist. Ähnliche Charakteristiken ergeben sich mit beiden Polaritäten.

     

Nuclear Magnetic Resonance Studies of Silicon Carbide Polytypes

The ²⁹Si MAS NMR spectra of the 2H, 4H, 6H, and 3C polytypes of silicon carbide are presented. An attempt is made to correlate differences in the chemical shifts with local atomic environment. The results of the analysis of the spectra of pure polytypes are used as a basic for the interpretation of the spectra of mixed polytypes and a discussion of the crystallinity and impurity levels of different samples. Carbon-13 chemical shifts obtained from spectra of the same polytypes are also tabulated.     

Casual reasoning in planning1

Reasoning about actions necessarily involves tracking the truth of assertions about the world over time. The SIPE planning system retains the efficiency of the STRIPS assumption for this while enhancing expressive power by allowing the specification of a causl theory. Separation of knowledge about causality from knowledge about actions relieves operators of much of their representational burden and allows them to be applicable in a wide range of contexts. The implementation of causal theories is described, together with examples and evaluations of the system's expressive power and efficiency.     

Rapid assessment of infant predictors of adult IQ: Midtwin-midparent analyses.

Assessed infant predictors of adult IQ with same-sex infant twins (114 pairs) and their parents. The midtwin–midparent design permits the rapid assessment of infant measures to predict later behavior, because the midparent score serves as a proxy for the infant's potential score at maturity. At 5, 7, and 9 mo, Ss were observed on the Fagan Test of Infant Intelligence, hand preference, vocalizations, selected Bayley Scales of Infant Development items, and a modified Bayley Infant Behavior Record. At 8 mo, Ss received the Visual Expectation Paradigm and an auditory discrimination task. Their parents received the Wechsler Adult Intelligence Scale—Revised (WAIS—R). Some infant measures, indicative of information processing, language ability, and temperament, predicted midparent IQ. This study extended and partially replicated findings from a previous midtwin–midparent cohort (L. F. DiLalla et al; see record 1991-04066-001). (PsycINFO Database Record (c) 2010 APA, all rights reserved)