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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 5061-5066 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A new approach to simulate electronic transport at high energies in silicon is introduced, which is based on a mixture of evolutionary optimization algorithms and the Monte Carlo technique. The optimization technique of the evolutionary algorithm is used to find electron distributions which are in agreement with a given physical quantity, for example, a measured substrate current. In this way, the evolutionary algorithm can calculate backward the electron distributions from results of measurements. A mutation operator, which is based on the Monte Carlo technique, is used to direct the optimization of the evolutionary algorithm toward physically correct distributions. A comparison of the results of this new approach with electron distributions calculated by a full band Monte Carlo program demonstrates both the backward calculation ability of the evolutionary algorithm and the correctness of the physical model in the Monte Carlo-like mutation operator. It becomes obvious that the electron distribution in silicon is mainly determined by the scattering rates. By suppressing the optimization of the evolutionary algorithm the Monte Carlo-like mutation operator alone was found to provide a powerful new type of Monte Carlo technique. While these methods are not as precise as a full band Monte Carlo approach, they are shown to be numerically efficient and give also a good fit to reliability related hot electron effects. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 3324-3326 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Dielectrically apertured vertical-cavity surface-emitting lasers are modeled using a Green's-function-based optical solver that allows calculation of the full-vector lasing modes and their threshold conditions. The laser is separated into subsystems consisting of a planar microcavity, a dielectric aperture, and an active gain medium. The exact Green's function solution for a radiating point source in the planar microcavity is then used to construct an eigenvalue equation for the self-consistent lasing modes. The derived eigenvalue equation is numerically solved to evaluate threshold dependence on aperture and cavity design. Results show a low threshold for thin oxide apertures placed at field antinodes, as well as for tapered oxides with thin tapers placed at field nodes. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 2526-2528 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report experimental results that replacing hydrogen with deuterium during the final wafer sintering process greatly reduces hot electron degradation effects in metal oxide semiconductor transistors due to a new giant isotope effect. Transistor lifetime improvements by factors of 10–50 are observed. A plausible physical theory suggests that the benefits of deuterium use may be general and also applicable to other areas of semiconductor device processing and fabrication. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 3147-3149 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Based on the energetics for hydrogen desorption from the interface between silicon and silicon-dioxide, we argue that the hard threshold for this effect may be considerably lower than the previously assumed value (∼3.6 eV). We support these findings further by recent experimental results related to the giant isotope effect in hydrogen related transistor degradation and the fact that degradation occurs also with relatively low supply voltages. We also show that the high threshold energy model is difficult to defend at these low voltages, even though electron–electron interactions provide a mechanism to create hot electrons with energies of ∼3.6 eV. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Semiconductors 33 (1999), S. 1002-1003 
    ISSN: 1063-7826
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The equilibrium surface densities of passivating adatoms for a silicon crystal in equilibrium with H2 or D2 gas are calculated. The difference in the surface densities of H and D adatoms is determined by the difference in their local surface vibrations. The equilibrium deuterium surface densities are an order of magnitude higher than the hydrogen surface densities.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of volcanology 59 (1997), S. 103-111 
    ISSN: 1432-0819
    Keywords: Key words Magma ; Mount St. Helens ; Cryptodome ; Viscosity ; Physical ; Rheological ; Experimental
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Physical properties of cryptodome and remelted samples of the Mount St. Helens grey dacite have been measured in the laboratory. The viscosity of cryptodome dacite measured by parallel–plate viscometry ranges from 10.82 to 9.94 log10 η (Pa s) (T=900–982  °C), and shrinkage effects were dilatometrically observed at T〉900  °C. The viscosity of remelted dacite samples measured by the micropenetration method is 10.60–9.25 log10 η (Pa s) (T=736–802  °C) and viscosities measured by rotational viscometry are 3.22–1.66 log10 η (Pa s) (T=1298–1594  °C). Comparison of the measured viscosity of cryptodome dacitic samples with the calculated viscosity of corresponding water-bearing melt demonstrates significant deviations between measured and calculated values. This difference reflects a combination of the effect of crystals and vesicles on the viscosity of dacite as well as the insufficient experimental basis for the calculation of crystal-bearing vesicular melt viscosities at low temperature. Assuming that the cryptodome magma of the 18 May 1980 Mount St. Helens eruption was residing at 900  °C with a phenocryst content of 30 vol.%, a vesicularity of 36 vol.% and a bulk water content of 0.6 wt.%, we estimate the magma viscosity to be 1010.8 Pa s.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Contributions to mineralogy and petrology 124 (1996), S. 19-28 
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The viscosities of hydrous haplogranitic melts synthesized by hydrothermal fusion at 2 kbar pressure and 800 to 1040° C have been measured at temperatures just above the glass transition and at a pressure of 1 bar using micropenetration techniques. The micropenetration viscometry has been performed in the viscosity range of 109 Pa s to 1012 Pa s. The samples ranged in water content from 0.4 to 3.5 wt%. For samples with up to 2.5 wt% H2O, the water contents have been determined using infrared spectroscopy obtained before and after each viscometry experiment to be constant over the duration of the measurements. Above this water content a measurable loss of water occurs during the viscometry. The viscosity data illustrate an extremely nonlinear decrease in viscosity with added water. The viscosity drops drastically with the addition of 0.5 wt% of water and then shallows out at water contents of 2 wt%. An additional viscosity datum point obtained from the analysis of fluid inclusions in a water-saturated HPG8 confirms a near invariance of the viscosity with the addition of water between 2 and 6 wt%. These measurements may be compared directly with the data of Hess et al. (1995, in press) for the effects of excess alkali and alkaline earth oxides on the viscosity of HPG8 (also obtained at 1 bar). The viscosity of the melts, compared on an equivalent molar basis, increases in the order H2O〈(Li2O〈Na2O〈 K2O〈Rb2O,Cs2O〈BaO〈SrO〈CaO〈MgO〈 BeO). The extraordinary decrease in melt viscosity with added water is poorly reproduced by the calculation scheme of Shaw (1972) for the range of water contents investigated here. The speciation of water in the quenched glasses can be used to quantify the dependence of the viscosity on hydroxyl content. Considering only the hydroxyl groups as active fluidizers in the hydrous melts the nonlinearity of the viscosity decrease and the difference with the effects of the alkali oxides becomes larger. Consequences for degassing calcalkaline rhyolite are discussed.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 222 (1976), S. 13-25 
    ISSN: 1433-8491
    Keywords: Maprotiline ; Double-Blind Trial ; Two Dosages ; Endogenous Depression ; AMP System ; Hamilton Scale for Depressions ; Maprotiline ; generic name ; Maprotilin ; Doppelblindversuch ; 2 Dosierungen ; endogene Depression ; AMP-System ; Hamilton ; Skala für Depressionen ; Maprotilin ; Markenname
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In einer klinischen Doppelblindstudie mit 150 mg und 225 mg Maprotilin täglich wurden Wirkung und Nebenwirkungen der beiden Dosierungen an je 10 depressiven Patienten miteinander verglichen. Durch hohe Tagesdosen (300 mg/die) an den ersten beiden Behandlungstagen wurde eine initiale Sättigung angestrebt. Die Patienten wurden an den Tagen 0, 2, 5, 10, 15, 20 und 30 klinisch untersucht und die Befunde dokumentiert mit dem AMP-System und der Hamilton-Skala für Depressionen. Laboruntersuchungen wurden an den Tagen 0, 10, 20 und 30 durchgeführt. Insgesamt entwickelte sich bei 5 Patienten ein Exanthem; davon waren 3 mit der höheren Dosierung behandelt worden. Bezüglich der Ausprägung eines feinschlägigen Tremors war die niedrigere Dosierung besser verträglich. Die von Behandlungsbeginn an zu beobachtende lineare Besserung weist auf den raschen Wirkungseintritt hin. Die häufig behauptete Latenz von 10–20 Tagen bis zum Wirkungsbeginn antidepressiver Substanzen kann nicht bestätigt werden. Einige Patienten besserten sich rasch innerhalb weniger Tage, während bei anderen Patienten erst nach längerer Behandlung eine wesentliche Besserung festzustellen war. Offenbar ist die Geschwindigkeit, mit der depressive Symptome durch ein Antidepressivum beeinflußt werden, individuell recht unterschiedlich. Statistisch konnte mit Hilfe der Kovarianzanalyse kein Wirkungsunterschied zwischen den beiden Dosierungen festgestellt werden. Die graphische Darstellung der Wirkungsprofile weist auf eine ausgeprägtere antidepressive Wirkung im höheren Dosierungsbereich hin. Da unter der höheren Dosierung jedoch mehr Nebenwirkungen zu beobachten waren, kann die Applikation der höheren Tagesdosis von Maprotilin nicht eindeutig empfohlen werden. Die Applikation von weniger als 150 mg Maprotilin täglich bei hospitalisierten depressiven Patienten scheint uns problematisch zu sein.
    Notes: Summary Effects and side-effects of 150 mg and 225 mg maprotiline per day were compared by means of a double-blind trial in 20 depressed inpatients. The first 2 days patients received a high initial dosage of 300 mg per day. Patients were examined on days 0, 2, 5, 10, 15, 20, and 30. Symptoms were evaluated by the AMP system and the Hamilton scale for depressions. Laboratory examinations were carried out on days 0, 10, 20, and 30. Exanthemas developed in five patients, three of whom were on the higher dosage. Moreover, the lower dosage caused less fine hand tremor. Coinciding with the beginning of treatment a linear decrease of depressive symptoms was noted. This demonstrates the rapid onset of the antidepressant effect. Moreover, contrary to what has been stated for antidepressants generally, the onset of action was frequently noted well before 10–20 days of treatment. Some patients improved within a few days while others needed more time. The time lag until antidepressants influence depressive symptoms shows pronounced individual differences. No significant difference between the two dosages was found. The profiles show a better antidepressant effect for the higher dosage; however, because of a higher incidence of side-effects on the higher dosage of maprotiline, it cannot be recommended as routine. On the other hand, depressive inpatients should receive a daily dosage of at least 150 mg. Our findings suggest a dose-effect relationship for maprotiline.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of neurology 219 (1978), S. 151-157 
    ISSN: 1432-1459
    Keywords: Oscillopsia, head-movement-dependent ; Peripheral vestibular lesions ; Brainstem lesions ; Cerebellar lesions ; Vestibulo-ocular reflex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Unter kopfbewegungsabhängiger Oszillopsie versteht man Scheinbewegungen der Umwelt während Kopfbewegungen. Ursache ist eine Funktionsstörung der vestibulo-okulären Reflexe. Dies hat eine mangelhafte Stabilisierung der Augen in Richtung auf das fixierte Objekt zur Folge, da bei rascheren Kopfbewegungen die visuellen Fixationsreflexe allein nicht ausreichen zur Blickstabilisierung. Patienten mit kopfbewegungsabhängiger Oszillopsie sind vor allem beim Gehen, aber auch beim Fahren auf holperigen Straßen stark behindert, da alles auf und ab oder hin und her tanzt, je nachdem der Kopf mehr vertikal oder mehr horizontal erschüttert wird. Am häufigsten kommt es nach beidseitigem Labyrinth- oder Nervus-vestibularis-Ausfall zu kopfbewegungsabhängiger Oszillopsie (Streptomycin u.ä. ototoxische Medikamente, operative Eingriffe). Aber auch Erkrankungen im Bereich der vestibulo-okulären Verbindungen im Hirnstamm und im Kleinhirn (Vestibulo- oder Archicerebellum) führen zu kopfbewegungsabhängiger Oszillopsie. Zur Lokalisierung solcher Läsionen können zusätzliche blickmotorische Störungen bei Hirnstamm- (internukleäre Ophthalmoplegie) oder Kleinhirn- (Rebound-Nystagmus usw.) Erkrankungen beigezogen werden. Besonderheiten der kopfbewegungsabhängigen Oszillopsie bei zentralnervösen Störungen sowie deren theoretischen Implikationen werden besprochen.
    Notes: Summary Head movement-dependent oscillopsia (HMDO) with peripheral vestibular, brainstem and cerebellar lesions is reviewed. The differentiation of this kind of oscillopsia is based mainly on clinical grounds. HMDO with bilateral abolition of caloric responses, and in the absence of disease of the central nervous system, is due to bilateral vestibular disease. HMDO in patients with internuclear ophthalmoplegia and other brainstem signs is probably due to a lesion of VOR pathways in or near the medial longitudinal fasciculus. The occurrence of HMDO with ataxia of gait and cerebellar eye movement disorders (rebound nystagmus, flutter-like oscillations), in the absence of brainstem lesions (medial longitudinal fasciculus), is clinical evidence for HMDO due to a cerebellar lesion. An attempt is made to associate the different kinds of oscillopsia with current knowledge of the vestibulo-ocular reflexes.
    Type of Medium: Electronic Resource
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