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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental mechanics 33 (1993), S. 228-233 
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper proposes a novel method for evaluating the dynamic characteristics of shock accelerometers under high acceleration levels and a wide frequency bandwidth. High accelerations of 103∼105m/s2 can be generated by the reflection of an elastic wave pulse propagating in a metal bar known as the Davies bar. The elastic wave pulse is produced by the collision of a projectile against one end of the bar, and is detected by straingages. The accelerometer to be characterized is attached to the other end of the bar. The one-dimensional theory of elastic waves enables the derivation of an input acceleration to the accelerometer from the measured strain. The dispersion of the elastic waves caused by the lateral inertia of the bar is compensated for by using a two-dimensional analytical solution. This method was validated by an experiment characterizing a piezoelectric-type accelerometer within the frequency band approximately 1 kHz∼70 kHz.
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  • 2
    ISSN: 1741-2765
    Keywords: Dynamic Testing ; Impact/Shock Analysis ; Interferometry (electronic recording) ; Wave Propagation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this paper, we propose a novel method for evaluating the frequency response of shock accelerometers using Davies bar and interferometry. The method adopts elastic wave pulses propagating in a thin circular bar for the generation of high accelerations. The accelerometer to be examined is attached to one end of the bar and experiences high accelerations of the order of 103∼105 m/s2. A laser interferometer system is newly designed for the absolute measurement of the bar end motion. It can measure the motion of a diffuse surface specimen at a speed of 10−3 ∼100 m/s. Uncertainty of the velocity measurement is estimated to be±6×10−4 m/s, proving a high potential for use in the primary calibration of shock accelerometers. Frequency characteristics of the accelerometer are determined by comparing the accelerometer's output with velocity data of the interferometry in the frequency domain. Two piezoelectric-type accelerometers are tested in the experiment, and their frequency characteristics are obtained over a wide frequency range up to several ten kilohertz. It is also shown that the results obtained using strain gages are consistent with those by this new method.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Experimental mechanics 38 (1998), S. 93-98 
    ISSN: 1741-2765
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Dynamic response of foil strain gages is investigated in the ranges of up to approximately 300 kHz in frequency, 2000 με in strain and 750 s−1 in strain rate. Impulsive input is applied to the gages using elastic wave pulses in a circular bar. The input is determined by measuring the velocity of the bar end with a laser interferometer. It was confirmed that deviations from the static gage factors do not exceed−5 percent within the frequency range up to 45 kHz, 110 kHz and more than 290 kHz for 20-mm, 10-mm and 3-mm gages, respectively, and that the gage length is the dominant factor in the gages' frequency characteristics. This paper also mentions self-generated voltages.
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  • 4
    ISSN: 1615-6102
    Keywords: Cytoskeleton ; Epidermal cell ; GFP-TUA6 fusion protein ; Microtubule ; Transgenic plants ; Tubulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Microtubules (MTs) were visualized in living cells of several tissues in transgenicArabidopsis thaliana. The transformed Arabidopsis plant was obtained by infecting it withAgrobacterium tumefaciens carrying the GFP-TUA6 plasmid. The fluorescence of the MTs was due to the fluorescence of GFP-TUA6 that was polymerized into the MTs. The distribution patterns of the visualized MTs in the living epidermal cells of leaves was similar to that in fixed epidermal cells. The actual destruction of MTs by oryzalin was observed in a living cell. Cytochalasin B exerts no effect on the distribution pattern of MTs. The fluorescence intensity of MTs was different among cells in different tissues.
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  • 5
    ISSN: 1615-6102
    Keywords: Arabidopsis thaliana ; Cortical microtubules ; Cytoskeleton ; Green-fluorescent-α-tubulin 6 fusion protein ; Microtubule ; Transgenic plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary AGFP-TUA6 (α-tubulin 6) gene was transduced in theArabidopsis thaliana genome, and the GFP-TUA6 protein was expressed by 20% of the total α-tubulin amount. The expressed GFP-TUA6 protein was incorporated into cortical microtubules (cMTs), so that the cMTs could be visualized under the fluorescence microscope in the living cells. The rearrangement of cMTs was observed at the tangential epidermal cell face of the hypocotyl. At the initial stage of light-induced cMT rearrangement from a transverse to an oblique or a longitudinal orientation, randomly oriented short MTs appeared. These MTs rapidly elongated obliquely or longitudinally as the transverse cMTs shortened. Finally, the transverse cMTs were replaced by the newly organized oblique or longitudinal cMTs. Reorganization of the cMTs took 50–70 min. Treatment of seedlings with 5 × 10−5 M cytochalasin B induced disarrayed cMTs. The involvement of cytochalasin B in the orientation of developing MTs is discussed.
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  • 6
    ISSN: 1614-7456
    Keywords: Autonomous robots ; Reinforcement learning ; Classifier systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A classifier system for the reinforcement learning control of autonomous mobile robots is proposed. The classifier system contains action selection, rules reproduction, and credit assignment mechanisms. An important feature of the classifier system is that it operates with continuous sensor and action spaces. The system is applied to the control of mobile robots. The local controllers use independent classifiers specified at the wheel-level. The controllers work autonomously, and with respect to each other represent dynamic systems connected through the external environment. The feasibility of the proposed system is tested in an experiment with a Khepera robot. It is shown that some patterns of global behavior can emerge from locally organized classifiers.
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  • 7
    ISSN: 1615-6102
    Keywords: Microfilaments ; Microtubules ; Freeze-substitution ; Micrasterias
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cortical microtubules and cortical microfilaments were visualized in cells ofMicrasterias pinnatifida treated by freeze-substitution, and the pattern of their distribution was reconstructed from serial sections. Most cortical microtubules accompanied the long microfilaments that ran parallel to the microtubules. Cortical microfilaments not accompanied by the microtubules were also found. They were short and slightly curved. Both types of cortical microfilament were not grouped into bundles, and were 6–7 nm in diameter, a value that corresponds to the diameter of filaments of F-actin.
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  • 8
    ISSN: 1615-6102
    Keywords: Ageing ; Benzyladenine ; Chloroplast ; Phaseolus vulgaris ; Plastoglobule ; Thylakoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Primary leaves of intact bean plants (Phaseolus vulgaris) were treated with benzyladenine (BA) at different stages of growth. Changes in the ultrastructure of chloroplasts and the contents of chlorophyll, carotenoid, and protein (soluble and insoluble) in leaves with different treatments were followed and compared. When BA was applied from an early stage, it increased the chloroplast size and the number of grana per chloroplast without any pronounced effect on the grana size. When BA treatment was stopped at the early stage, these effects remained for a while and then diminished. When BA treatment was begun at a late stage, such marked effects were not observed, suggesting that only young leaves could respond to BA in that manner. However, the late treatment efficiently prevented the process of the last stage of leaf senescence characterized by disintegration of thylakoids with concomitant increase in the plastoglobule size. Chlorophyll, carotenoid, and insoluble protein contents per leaf followed similar changes in chloroplast length and the number of grana per chloroplast section.
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  • 9
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 117-118 (Jan. 1993), p. 273-278 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 10
    ISSN: 1573-4927
    Keywords: protease inhibitors ; fungal protease ; chymotrypsin ; genetic variants ; silkworm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Many electrophoretic variants of hemolymph inhibitors of proteases from Aspergillus mellus and pancreatic α-chymotrypsin were found using 126 silkworm strains. Six inhibitors of the fungal protease were detected and eight of chymotryspin; the distribution of inhibitors among Japanese, Chinese, and European races was investigated. Comparison of electrophoretic patterns from F1 hybrids and parents showed that the offspring produce inhibitors of both parental types. Segregation in F2 and backcrossing suggest that the expression of each inhibitor is controlled in most cases by a pair of alleles which are responsible for strong and null bands. Two bands of fungal protease inhibitors C and D were controlled by codominant alleles. These results suggest that polymorphism of hemolymph protease inhibitors in the silkworm would be a useful experimental system for the study of the genetic control of protease inhibitors.
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