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  • Chemical Engineering  (5)
  • 42.55D  (4)
  • Adaptation  (2)
  • Arabidopsis  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Scaling and performance of CO2 lasers at supra-atmospheric pressure (1985)
    Springer
    Applied physics 37 (1985), S. 171-179 
    Details
    ISSN: 1432-0649
    Keywords: 42.55D ; 42.60B ; 58.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The performance of a compact uv photo-preionized TE laser is studied in the pressure range 1–5 bar. As the pressure is increased, the laser pulse shape is little altered, but both the peak power and the total output pulse energy increase significantly with pressure, even for constant input electrical energy. For various gas mixtures and excitation source capacitors the measurements suggest approximate output energy scaling with the product of the source charge per unit electrode area [C.m−2] and the molecular partial pressure [CO2+N2+CO]. This is explained in terms of the pressure-dependent discharge impedance. An input-energy-related discharge instability limits the optimum laser pressure to 1.5–2.5 bar, and we show that, at constant input energy, the instability boundary depends on the molecular partial pressure alone. The pre-ionization photo-electron yield varies negligibly with pressure, but the discharge tolerance to added oxygen decreases asp −3 top −4, dependent on gas mixture. Nevertheless sealed operation for 〉105 shots has been obtained with a 5% CO2∶5% CO∶3% N2∶2% H2∶85% He gas mixture at a total pressure of 5 bar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692081
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  • 2
    Electronic Resource
    Electronic Resource
    Effective and simplified hybrid TEA laser design and operation (1984)
    Springer
    Applied physics 33 (1984), S. 99-101 
    Details
    ISSN: 1432-0649
    Keywords: 42.60B ; 42.55D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A compact hybrid TEA CO2 laser has been developed which, when operated with the low pressure section well below oscillation threshold, demonstrates that little cw gain is necessary to ensure single longitudinal mode (SLM) output pulses with peak power, energy and pulse shape approaching those of normal multi-mode operation. This has allowed reliable SLM operation to be obtained with a very short, wide bore rf-excited low-pressure section, making feasible simple single-mode, large-aperture TEA lasers with high peak powers and energies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688354
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  • 3
    Electronic Resource
    Electronic Resource
    X-ray preionized CO2 laser (1985)
    Springer
    Applied physics 37 (1985), S. 219-221 
    Details
    ISSN: 1432-0649
    Keywords: 42.55D ; 33.80E ; 52.80 ; 42.60B
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A short pulse (100 ns) high-energy x-ray source has been used to preionize a transversely excited carbon dioxide gas discharge laser of 600 cm3 active volume. The maximum output power of 60 MW in a 50 ns FWHM pulse was achieved from a CO2−N2−He−CO−Xe static gas mixture at 600 Torr pressure. The energy conversion efficiency was 6%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692945
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  • 4
    Electronic Resource
    Electronic Resource
    Negative ion effects in CO2 convection laser discharges (1978)
    Springer
    Applied physics 16 (1978), S. 111-118 
    Details
    ISSN: 1432-0630
    Keywords: 42.55D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Negative ions are computed to be formed on a time scale and in quantities such that they may be a cause of plasma instability observed in low pressure electrical discharge convection CO2 lasers. In a typical CO2−N2−He−H2O laser mixture the principal ions are CO 3 − , CO 4 − and H− with the total negative ion densityn − given by 0.1n e 〈n −〈n e , wheren e is the electron density: but if the gases are re-cycled or if there is an air leak NO 2 − and NO 3 − are formed in significant amounts andn − can become greater thann e in a time considerably less than the gas dwell time in the electrical excitation discharge. CO is effective in reducingn − in a system without re-cycling, but is ineffective in a re-cycled system with the oxides of nitrogen present.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00931431
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  • 5
    Electronic Resource
    Electronic Resource
    Neural correlates of motion after-effects in cat striate cortical neurones: monocular adaptation (1988)
    Springer
    Experimental brain research 72 (1988), S. 1-20 
    Details
    ISSN: 1432-1106
    Keywords: Vision ; Visual cortex ; Adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Motion after-effects were elicited from striate cortical cells in lightly-anaesthetized cats, by adapting with square-wave gratings or randomly textured fields drifting steadily and continuously in preferred or null directions. The time-course and recovery of responsiveness following adaptation were assessed with moving bars, gratings or textured fields. Results were compared with controls in which the adapting stimulus was replaced by a uniform field of identical mean luminance, and also assessed in relation to the strength and time course of adaptation. Within 30–60 s adaptation, firing declined to a steady-state. Induced after-effects were direction-specific, and manifest as a transitory depression in response to the direction of prior adaptation, recovering to control levels in 30–60 s. Maximal after effects were induced by gratings of optimal drift velocity and spatial frequency. With rare exceptions after-effects were restricted to driven activity; no consistent effects on resting discharge were observed. The onset of adaptation, and the recovery period, were more rapid in simple cells, although after effects of comparable strength were elicited from simple and from standard complex cells. Special complex cells, including many of the more profoundly texture-sensitive neurones in the cortex, were more resistant to adaptation. The results support the conclusion that psychophysically measured adaptation and induced motion after-effect phenomena reflect the known properties of cortical neurones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248495
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  • 6
    Electronic Resource
    Electronic Resource
    The pattern specificity of velocity aftereffects (1985)
    Springer
    Experimental brain research 60 (1985), S. 71-78 
    Details
    ISSN: 1432-1106
    Keywords: Motion ; Velocity ; Visual cortex ; Adaptation ; Texture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Interactions between two different visual patterns, a coarse grating and a fine texture pattern, were investigated in the context of velocity aftereffects in human subjects. The perceived velocity shift, in which the perceived velocity of a moving test pattern is reduced following exposure to a similarly moving adaptation pattern, is apparent when the adaptation and test patterns are of the same or different types. The aftereffect transfers interocularly in both cases. The directional tuning of the aftereffect is broad, and has a different profile for texture adaptation than for bar adaptation. When adaptation is to a composite stimulus comprising independently moving bars and texture, the aftereffect varies according to the nature of the test pattern. The results are discussed with reference to interactions between the responses of neurones in feline striate cortex to the two types of pattern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237020
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  • 7
    Electronic Resource
    Electronic Resource
    Ethylene binding sites in higher plants (1996)
    Springer
    Plant growth regulation 18 (1996), S. 71-77 
    Details
    ISSN: 1573-5087
    Keywords: Arabidopsis ; ethylene ; ethylene binding protein ; signal transduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A review of work carried out on ethylene binding in higher plants is presented. The use of radio-labelled displacement assays has identified specific 14C-ethylene binding in all tissues so far studied. virtually all higher plants studied contain at least two classes of ethylene binding site, one of which fully associates and dissociates in about 2 h and a class of sites that takes up to 20 h to become fully saturated. Although the types of site differ in their rate constants of association they have similar and high affinities for ethylene. A series of Arabidopsis thaliana mutants shown to vary in sensitivity to ethylene have been analysed for 14C-ethylene binding. One mutant, eti 5, which was shown to be unaffected by ethylene concentrations of up to 10,000 μL L−1 was also shown to exhibit reduced binding. In vivo and in vitro studies on pea have shown that ethylene binding can be detected in this tissue. In vitro studies have shown that both membrane and cytosolic fractions contain measurable amounts of ethylene binding. Interestingly, cytosolic ethylene binding consisted only of the fast associating/dissociating type. Developing cotyledons of Phaseolus vulgaris contain a higher concentration of ethylene binding sites that other tissues and only contain the slow dissociating component. These facets have allowed the purification of ethylene binding protein(s) (EBP) from this tissue. The proteins which bind ethylene can be resolved into two bands of 26 and 28 kDa on semi-denaturing PAGE and the proteins appear to be single entities on a 2-D gels. Data will be presented which indicate a possible role for heterotrimetric G-proteins in the early stages of the ethylene signal transduction pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028490
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  • 8
    Electronic Resource
    Electronic Resource
    Studies on the possible role of protein phosphorylation in the transduction of the ethylene signal (1996)
    Springer
    Plant growth regulation 18 (1996), S. 135-141 
    Details
    ISSN: 1573-5087
    Keywords: Arabidopsis ; EBP ; ethylene ; phosphorylation ; receptors ; signal transduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Previous work in our laboratory has demonstrated the existence of high affinity binding sites for the plant growth regulator ethylene. The ethylene binding protein (EBP), from Phaseolus cotyledons, shows many of the characteristics of a functional receptor for ethylene, has been purified on SDS-PAGE and polyclonal antibodies raised in rabbits. Current work involves the investigation of the ethylene transduction signal in a number of ethylene-responsive tissues. In peas, it has been shown that ethylene promotes the phosphorylation of specific proteins of similar molecular weight to the EBP from Phaseolus. Such ethylene-induced phosphorylation can be inhibited by the ethylene antagonist, 2,5-NBD. The antibodies raised to the EBP from Phaseolus have been shown to immunoprecipitate 32P-labelled proteins from membrane protein preparations obtained from pea tissue. Studies on ethylene binding in pea have also shown that the binding of ethylene may be regulated by phosphorylation. Thus, under conditions which promote phosphorylation, binding is inhibited, whereas the reverse is true under conditions which enhance dephosphorylation. Further work is described which examines the effect of protein kinase, protein phosphatase and calcium channel inhibitors on ethylene-induced phosphorylation in peas, together with wild-type (WT) and ethylene insensitive (eti) mutants of Arabidopsis thaliana. The effects of these treatments can be monitored in vivo using the ethylene-induced triple response as a screen. Furthermore, the protein profiles of such treated seedlings can then be compared by labelling protein extracts with 32P and subjecting the samples to SDS-PAGE followed by autoradiography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00028498
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  • 9
    Electronic Resource
    Electronic Resource
    Pumping characteristics of self-wiping twin-screw extruders - A theoretical and experimental study on biopolymer extrusion (1989)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 433-440 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 flow of Newtonian and non-Newtonian fluids which obeys a power law relationship between shear stress and shear rate has been modeled in the melt conveying section of a self-wiping co-rotating twin-screw extruder using a finite element analysis of an unwound channel section. Predictions of throughput against pressure gradient are compared with experimentally obtained results for maize grits which is represented as a power law material. Rheological data applicable to extrusion simulation were obtained from capillary rheometry. Comparisons are reasonable with predicted characteristic showing similar behavior.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760290702
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  • 10
    Electronic Resource
    Electronic Resource
    Family plots for evaluating physical properties of organosilicon compounds (1994)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 40 (1994), S. 373-377 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690400217
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