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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 86 (1991), S. 324-332 
    ISSN: 1432-1106
    Keywords: Vision ; Optokinetic nystagmus ; Eye movements ; Plaids ; Brainstem ; Motion perception ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have recorded the direction of optokinetic nystagmus (OKN) elicited by moving plaid patterns in order to dissociate the pathways that mediate horizontal OKN. The plaids used comprised two drifting sinusoidal gratings arranged such that their individual directions of drift were very different from the direction of coherent motion of the overall pattern. The direction of OKN with binocular viewing was close to the mean of the component directions, suggesting a dominant influence of cortical visual neurons that respond to oriented one-dimensional components of the image. But the direction of OKN was consistently shifted slightly towards the direction of motion of the overall pattern, suggesting a secondary influence responsive to pattern direction. OKN recordings obtained during monocular viewing suggest that this secondary influence reflects the direct retinal pathway to the brainstem structures mediating OKN.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 17 (1973), S. 315-332 
    ISSN: 1432-1106
    Keywords: Red nucleus ; Unit recording ; Motor cortex ; Topographical organization ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A topographical study of the cortico-rubrospinal pathway was conducted in cats anesthetized with chloralose. Extracellular unit recordings were made from cells in the red nucleus projecting to the spinal cord. They were identified by antidromic invasion following stimulation of their axones at the 2nd cervical and 9th thoracic levels of the spinal cord. I. The pericruciate cortical regions from which spikes could be induced in rubrospinal neurons were limited to the lateral part of the anterior sigmoid gyrus, the lateral sigmoid gyrus and the anterior part of the posterior sigmoid gyrus. No responses were obtained from stimulation of the medial part of the anterior sigmoid gyrus or the gyrus proreus. Compared to the somatotopic organization of the motor cortex for the cat described by Woolsey (1958), our results show that the rubrospinal cells receive projections from the motor cortex controlling proximal and distal muscles but not axial muscles. II. Neurons projecting to the cervico-thoracic cord receive afferents from the lateral part of the anterior sigmoid gyrus and the lateral sigmoid gyrus whereas those projecting to the lumbo-sacral cord receive projections from the entire surface of the sigmoid gyrus except the medial part of the anterior sigmoid gyrus and the gyrus proreus. III. A latero-medial organization of cells within the red nucleus was found according to the origin of their cortical afferents. Rubrospinal neurons with fibers terminating in the cervical or thoracic cord receive projections from the motor cortex controlling the proximal musculature of the forelimb when they are located in the dorso-lateral region of the nucleus and the entire forelimb motor cortex when they are located in the medial part of the nucleus. It is suggested that this organization may indicate a control of proximal forelimb musculature by dorsolateral rubrospinal cells and distal musculature by medial cells. IV. Rubrospinal cells placed medially in the nucleus receive more convergent projections (i.e. from a greater cortical surface) than cells placed more laterally. It was shown that for certain cells the convergence occurs in the direct pathway. These results are discussed in terms of a functional organization allowing coordinated movements of different segments of a single limb or of different limbs.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 60 (1985), S. 411-416 
    ISSN: 1432-1106
    Keywords: Vision ; Motion after-effects ; Cat ; Visual cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Responses of striate cortical neurones to bars of optimal orientation and width, moving with fixed velocity, were recorded in the lightly anaesthetized cat. Effects of periods of pre-adaptation with square-wave gratings of variable spatial frequency and velocity, drifting continuously in each cell's preferred or null directions, were investigated. Variations of cells' directional bias and responsiveness to oriented bars were assessed in relation to the degree and time-course of pre-adaptation to drifting gratings, compared with the preceding level of firing when exposed to uniform backgrounds of the same average luminance. All cells showed some susceptibility to pre-adapting moving gratings: subsequent responses to a bar were initially depressed in the direction of pre-adaptation and, in direction-biased or bidirectional cells, were enhanced in the opposite direction, compared with bar responses following exposure merely to a uniform background. These effects were strongest and most consistent amongst standard complex cells and weakest amongst special complex cells: maximal effects were obtained with adapting gratings of optimal velocity and spatial frequency.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 28 (1977), S. 405-409 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Chromverarmung nichtrostender Stähle beim Glühen im VakuumBei der selektiven Oxidation von Chrom in nichtrostenden Stählen wird das Oxidatinos-verhalten stark von den Veränderungen der Chromkonzentration an der Metalloberfläche und im Metall beeinflußt. Nach den bisherigen Annahmen verhält sich das Chrom bei der selektiven Oxidation ebenso wie bei der Verflüchtigung während des Vakuumerhitzens auf hohe Temperaturen. In der vorliegenden Arbeit wird die Verdampfung von Chrom aus Stahl 316 bei Vakuumanlassen bei 1000 °C mittels energiedispersiver Röntgenstrahlen- und Neutronenaktivierungsanalyse untersucht. Es wird festgestellt, daß der Chromverlust aus austenitischen nichtrostenden Stählen durch Interdiffusion in der Legierung kontrolliert wird. Entsprechend der Vorhersage nimmt die Chromkonzentration an der Metalloberfläche mit zunehmender Erhitzungsdauer ab. Das Chromverarmungsprofil im Metall stimmt gut über in mit einem früher obgeleiteten Modell, abgesehen von einer anomalen Zone in Oberflächennähe. Die hohe Auflösung der Neutronenaktivierungstechnik läßt erkennen, daß es sich um eine etwa 2μm dicke Zone handelt, wo die Chromkonzentration steiler absinkt als es den erwartungen entspricht.
    Notes: During selective chromium Oxidation of stainless steels the changes in chromium concentration at the metal surface and in the metal have an important bearing on the overall oxidation performance. It has been proposed that an analogue of chromium behaviour during selective oxidation is obtained from volatilisation of chromium during high temperature vacuum annealing. In the present report the evaporation of chromium from 316 type of steel, vacuum annealed at 1000 °C, has been investigated by menas of energy dispersive X-ray analysis and by neutron activation analysis. It was established that chromium loss from austenitic stainless steels is rate controlled by interdiffusion in the alloy. As predicted the chromium concentration at the metal surface decreased with increasing vacuum annealing time. The chromium depletion profile in the metal was in good agreement with the previously derived model apart from an anomalous region near the surface. Here the higher resolution of the neutron activation technique indicated a zone within ∼2μm of the surface where the chromium concentration decreased more steeply than expected.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 29 (1978), S. 246-250 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Konzentrationsprofile in einem Duplex-Oxidzunder auf Stahl 316Konzentrationsprofile in auf vakuumangelassenem Stahl 316 entstandenem Duplex-Oxidzunder wurden mit Neutronenaktivierungsanalyse und energiedispersiver Analyse untersucht. Gute qualitative Übereinstimmung zwischen den beiden Methoden ergab sich für das Konzentrationsprofil von Chrom in der äußeren Oxidschicht; die Ergebnisse deuten auf eine geringe Geschwindigkeit der Stromdiffusion in die äußere Magnetitschicht. Bei der inneren Oxidschicht ist die Übereinstimmung zwischen den beiden Methoden weniger gut, da die Ergebnisse der Neutronenaktivierung durch die Anwesenheit von Metall in der Querschnittsfläche verfälscht werden. Die Ergebnisse der energiedispersiven Analysen dieser Schicht stimmen mit früheren Befunden überein, wonach normale oder nichtselektive Oxydation auftritt.
    Notes: Concentration profiles through duplex scales formed on vacuum annealed 316 stainless steel have been investigated using neutron activation analysis and energy dispersive analysis. Good qualitative agreement between the two analytical techniques was obtained for chromium concentration profiles in the outer oxide. These indicated a low rate of chromium diffusion into the Fe3O4 layer. There was less agreement between the two methods in the inner oxide as the neutron activation results were complicated by the presence of metal in sections through this oxide layer. The energy dispersive results in this layer were consistent with previous findings which indicated conservative or non selective oxidation occurring.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 30 (1979), S. 100-104 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Oxidation eines 18/8 Stahls in KohlendioxidDas Oxidationsverhalten von 18/8-Stahl wurde im Temperaturbereich 873-1258K (600-985°C) durch kontinuierliche Messung der Gewichtszunahme, metallographische Methoden und Rasterelektronenmikroskopie untersucht. Auf eine anfänglich hohe Oxidationsgeschwindigkeit folgt eine Periode mit wesentlich geringerer Oxidation. Im Anfangsstadium entsteht ein zweischichtiger Zunder. weshalb die Abnahme der Oxidationsgeschwindigkeit wahrscheinlich durch die Bildung eines geordneten, chromreichen Spinells an der Grenzfläche Oxid/Metall bedingt sein dürfte.Wenn unter Verwendung des Modells von Hales die Bildung von „heilenden„ Phasen berücksichtigt wurde, ergab sich eine echte parabolische Zeitkonstante: \documentclass{article}\pagestyle{empty}\begin{document}$$ k_p = {\rm 1}{ .8\,\, exp}\left({\frac{{ - {\rm 230}}}{{RT}}} \right)g^2\,\, cm^{ - 4} \,\,\sec ^{ - 1} $$\end{document}Hierin ist die Aktivierungsenergie in KJ. mol-1 (55 kcal · mol-1) ausgedrückt.
    Notes: The oxidation behaviour of an 18/8 type stainless steel has been studied in the temperature range 873-1258 K (600-985 °C) by continous weight gain measurements, metallography and scanning electron microscopy. An initial high oxidation rate was followed by a much slower rate. Duplex scales formed at an early stage of oxidation and the decrease in oxidation rate is probably due to the formation of an ordered chromium rich spinel at the oxide/metal interface.A ture parabolic rate constant (kp) was obtained taking into account the formation of the “healing” phase using the Hales model. This gave: \documentclass{article}\pagestyle{empty}\begin{document}$$ k_p = {1.8\,\, exp}\left({\frac{{ - {\rm 230}}}{{RT}}} \right)g^2\,\, cm^{ - 4} \,\,\sec ^{ - 1} $$\end{document}. where the activation energy is expressed in KJ · mole-1. (55 Kcals mole-1).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 29 (1978), S. 441-444 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Diffusion von Übergangsmetallen in auf Stahl 316 aufgewachsenem Duplex-OxidMit der Methode der sukzessiven Abtragung wurden nach Diffusionsglühen bei 1273 K Konzentrationsprofile von radioaktiven Isotopen (Chrom, Mangan und Eisen) in einem auf Stahl 316 entstandenen doppelschichtigem Zunder ermittelt. Das Eisenisotop diffundiert danach normalerweise sowohl durch die innere als auch durch die äußere Zunderschicht. Die Konzentration der Isotopen von Chrom und Mangan nimmt in der äußeren Magnetitschicht nach Außen hin zu, zeigt aber in der inneren Spinellschicht ein normales Konzentrationsprofil. Die Diffusionskoeffizienten - ermittelt aufgrund der Konzentrationsprofile - lagen, bezogen auf die Diffusion in der Spinellphase, zwischen 6 × 10-12 und 3 × 10-11 cm2 sec-1.
    Notes: Concentration profiles of chromium, maganese and iron radioactive tracers through a duplex oxide grown on 316 stainless steel have been obtained after a diffusion anneal at 1273 K using the serial sectioning technique. The iron tracer diffused normally in both inner and outer oxides of the duplex scale. The concentration of the chromium and manganese tracers increased with increasing penetration into the outer Fe3O4 layer but showed a normal profile in the inner spinel. The diffusion coefficients obtained from the profiles were in the range 6 × 10-12 - 3 × 10-11 cm2 sec-1 for diffusion in the spinel phases.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 32 (1981), S. 1-7 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Die Oxidation von 18/8 Stählen in Kohlendioxid + 2% Kohlenmonoxid bei hohem DruckDie Oxidation verschiedener 18/8 Stähle in Gemischen aus Kohlendioxid und 2% Kohlenmonoxid wurde im Temperaturbereich 550 bis 650°C durch intermittierende Messung der Gewichtszunahme, metallographische Untersuchung, Fraktographie und Rasterelektronenmikroskopie verfolgt. Schon in einem frühen Oxidationsstadium entsteht eine Duplex-Zunderschicht. Die Gewichtszunahme/Zeit-Kurven zeigen zwei Prozeßstufen, und zwar ein Anfangsstadium, das sich exponentiell dem zweiten langsameren Stadium annähert. Die Geschwindigkeit der Duplex-Zunderbildung zeigte nicht die übliche Temperaturabhängigkeit; indessen wurde bei etwa 600°C ein Maximum der Geschwindigkeit festgestellt. Die sekundären Verzunderungsgeschwindigkeiten waren bei 650 und 550°C deutlich zu erkennen und lagen bei der niedrigeren Temperatur höher. Im Zunder traten verschiedene Spinelle auf. Die erhaltenen Ergebnisse werden mit der Annahme gedeutet, daß Kationendiffusion durch verschiedene innere Spinelle der geschwindigkeitsbestimmende Schritt ist.
    Notes: The oxidation of a variety of 18/8 stainless steels in high pressure CO2/2% CO has been followed in the temperature range 550-650°C using intermittent weight gain measurement metallography, fractography and scanning electron microscopy. Duplex scales formed at an early stage of oxidation. The weight gain curves were analysed in terms of a two stage process, the initial stage exponentially approaching a slower secondary stage. The primary rate of duplex scale formation did not show the usual temperature dependence. Rather a maximum in the rate was observed at ∼600°C. Secondary rates were well established at 650°C and 550°C the secondary rate at 550°C, however, being higher than that at 650°C. Various spinels occurred and the results are explained in terms of the rate controlling process being cation diffusion through different inner spinels.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 33 (1982), S. 77-82 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Detaillierte Untersuchung von zwei nichtrostenden Stählen nach 20 000 Stunden Oxidation in CO2/2% CO bei hohem DruckMit Hilfe von Rasterelektronenmikroskopie, Mikrosonde und Kernmikrosonde wurden zwei Proben von 18/8-Stählen eingehend untersucht; die Proben waren repräsentativ für die beiden Extreme des nach einem parabolischen Zeitgesetz bei 600°C gewachsenen Zunders. Auf dem im Vakuum angelassenen Stahl 316 erfolgte die Zunderbildung mit hoher Geschwindigkeit, wobei innen eine vorwiegend einheitliche Spinellschicht vorlag, jedoch mit einem chromreichen und nickelarmen Spinell (geheiltes Oxid) an der Grenzfläche Metall/Zunder. Das darunter befindliche Metall war stark aufgekohlt, wobei die Kohlenstoffkonzentration in der Nähe der Metalloberfläche etwa 1 Gew.-% betrug. Bei dem Material mit geringerer Verzunderungsgeschwindigkeit war die innere Zunderschicht komplexer aufgebaut und das Metall weniger stark aufgekohlt. Die Ergebnisse werden unter Berücksichtigung der Zusammensetzung der inneren Oxidschicht und der unter Ausheilung erfolgenden Schichtbildung erläutert, wobei dem dort vorliegenden Sauerstoffpotential der geschwindigkeitsbestimmende Einfluß zugeschrieben wird.
    Notes: Detailed examination has been carried out on two specimens of 18/8 steels representing the extremes of the rates of parabolic duplex scale growth at 600°C using metallography, scanning electron microscopy, microprobe and nuclear microprobe analysis.The high growth rate material, vacuum annealed 316, had an inner layer of mainly a uniform spinel but with a chromium rich low nickel spinel (healed oxide) at the metal interface. The underlying alloy was extensively carburised with a carbon concentration near the metal surface of ∼1 wt%. The low growth rate material had a more complex inner layer and a much lower degree of carburisation. The results are explained in terms of the composition of the inner oxide and the rate of healing layer formation being controlled by the prevailing oxygen potential there.
    Additional Material: 5 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 3 (1960), S. 310-315 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The preparation of condensation products of poly(4-vinyl-acetophenone) with various substituted benzaldehydes is described. As in the case of the products obtained by condensing the poly(4-vinylacetophenone) with benzaldehyde, these, too, show to varying degrees the property of becoming insoluble when exposed to light. This sensitivity to light is generally higher where the aldehyde used contains electrondonating substituent groups in the para-position. This, in turn, is also related to the ability of such products to absorb a larger proportion of the longer wavelength portion of the emitted light.
    Additional Material: 5 Tab.
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