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  • 1
    Digitale Medien
    Digitale Medien
    Moiré interferometry of short wavelength Rayleigh–Taylor growth : Proceedings of the 12th topical conference on high temperature plasma diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 637-641 
    Details
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: One of the most critical quantities to be measured for better understanding of the ablative Rayleigh–Taylor (RT) instability is the cutoff wavelength below which the RT instability is stabilized. Unfortunately, this wavelength is expected to be below or close to spatial resolutions of most x-ray imagers used in the RT experiments. We propose and test a new technique using moiré interferometry to convert short wavelength perturbations to longer wavelength perturbations. The RT target is backlit by x rays and imaged just like in conventional experiments, but a grid mask is inserted between the target and the x-ray imager. The grid mask is one dimensional grid with a period slightly different from the wavelength of the RT target. It is set so that the grid and the RT perturbation groove are parallel to each other. With this operation, the long wavelength moiré interference is measured as the beat with the RT target. As an initial test, we use a grid mask with 10 μm period coupled to RT targets with 8 and 12 μm perturbation wavelengths. The corresponding moiré interference wavelengths are 40 and 60 μm, respectively.© 1998 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1149434
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  • 2
    Digitale Medien
    Digitale Medien
    Growth, microstructure, and strain relaxation in low-temperature epitaxial Si1−xGex alloys deposited on Si(001) from hyperthermal beams (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 812-821 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Epitaxial Si1−xGex(001) alloy films, with 0.15≤x≤0.30, were grown on Si(001) at temperatures Ts ranging from 300 to 550 °C using hyperthermal Si (average energy 〈ESi〉(approximately-equal-to)18 eV) and Ge (〈EGe〉(approximately-equal-to)15 eV) beams. The deposition rate was 0.1 nm s−1 and film thicknesses ranged from 30 nm to 0.8 μm. The energetic Si and Ge beams are generated by bombarding Si and Ge targets with 1 keV Kr+ ions from double-grid, multiaperture, broad ion-beam sources in a system geometry established based upon TRIM simulations of energy-dependent angular distributions of sputtered and backscattered particles. A combination of high-resolution plan-view and cross-sectional transmission electron microscopy, high-resolution x-ray diffraction, Rutherford backscattering spectroscopy, channeling, and axial angular-yield profiles demonstrated that the films are of extremely high crystalline quality. Critical layer thicknesses hc for strain relaxation in these alloys were found to increase rapidly with decreasing growth temperature. For Si0.70Ge0.30, hc ranged from 35 nm at Ts=550 °C to 650 nm at 350 °C compared to an equilibrium value of (approximately-equal-to)8 nm. At even lower growth temperatures, hc becomes larger than critical epitaxial layer thicknesses, (approximately-greater-than)1 μm at 300 °C. In addition, atomic force microscopy studies showed that strain-induced roughening, which occurs at elevated growth temperatures, is strongly suppressed at Ts between 300 and 400 °C with no indication of kinetic roughening. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.362918
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  • 3
    Digitale Medien
    Digitale Medien
    Effects of ion energy and arrival rate on the composition of zirconium oxide films prepared by ion-beam assisted deposition (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 1177-1181 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Thin zirconium oxide films were grown using the ion-beam assisted deposition method. Zirconium metal was evaporated by an electron beam and condensed on a Si substrate, while oxygen ions were directed simultaneously onto the substrate, allowing the fundamental deposition parameters of ion energy and arrival rate ratio ARR(O/Zr) to be measured and controlled easily. X-ray photoelectron spectroscopy (XPS) was used to study the oxidation and the composition of the films. XPS analyses indicated the presence of four oxidation states of zirconium (Zr4+−Zr1+) in Zr 3d spectra and two peaks in O 1s spectra; Zr4+ is a predominant ion in all the films and the two peaks in O 1s spectra are related to the oxide and to hydroxyl groups and/or carbonates, respectively. Composition analyses of the films suggested that these oxygen-associated species may be bound to zirconium. The variation of composition as a function of ion energy (from 2 to 20 keV) and ARR(O/Zr) (at 0.54 and 1.09) could be explained with the preferential sputtering of zirconium from the growing film by incoming oxygen ions and the incorporation of oxygen ions into the film. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.362855
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  • 4
    Digitale Medien
    Digitale Medien
    Second polar body retention and gynogenesis induced by thermal shock in pink salmon, Oncorhynchus gorbuscha (Walbaum) (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 26 (1995), S. 0 
    Details
    ISSN: 1365-2109
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Insemination of oocytes from six different salmon with irradiated heterospecific sperm combined with thermal shocks 10 min after activation successfully induced gynogenesis in pink salmon, Oncorhynchus gorbuscha (Walbaum). Biochemical genetic analysis and morphology of larvae con firmed their gynogenetic parentage, Thermal shocks of 26oC beginning 10 min after fertilization and lasting 15-30 min gave high yields of gynogenetic salmon (32% of normal diploid hatching, average of six females; 70% in oocytes from one female treated 20 min): shocks of 28oC lasting 10-16 min also gave high yields (2 5%), Shocks of 30oC lasting 6-12 min gave lesser yields (10%), Female donors varied significantly in the susceptibility of their oocytes to treatment (15-70% range of yield to average best treatment) but females did not interact significantly with heat shock treatment: different heat shocks had relatively the same effect on all females.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2109.1995.tb00904.x
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  • 5
    Digitale Medien
    Digitale Medien
    Absolute configuration of the active stereoisomer of new rice fungicide Carpropamid (1999)
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 55 (1999), S. 1025-1027 
    Details
    ISSN: 1600-5759
    Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1107/S0108270199002504
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  • 6
    Digitale Medien
    Digitale Medien
    Gravitationally redshifted emission implying an accretion disk and massive black hole in the active galaxy MCG63015 (1995)
    [s.l.] : Nature Publishing Group
    Nature 375 (1995), S. 659-661 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Recent optical and radio observations2 4 of gas motions show a large, central concentration of mass (probably a black hole) in a number of galaxies. But this gas lies beyond ~30,000 Schwarzschild radii so the characteristic signatures of the black hole itself-relativistic ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/375659a0
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  • 7
    Digitale Medien
    Digitale Medien
    Electroless deposition of Ni–B, Co–B and Ni–Co–B alloys using dimethylamineborane as a reducing agent (1998)
    Springer
    Journal of applied electrochemistry 28 (1998), S. 559-563 
    Details
    ISSN: 1572-8838
    Schlagwort(e): electroless Ni–Co–B alloy ; dimethylamineborane ; complexing agent ; deposition rate ; crystal structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract Fundamental aspects of electroless Ni–B, Co–B and Ni–Co–B alloys have been systematically examined. The composition, crystal structure and deposition rate of the alloys were determined as a function of the concentration of reducing agent (dimethylamineborane) and complexing agents (tartrate, citrate, malonate and succinic acid), bath pH and Ni2+/Co2+ ratio. Changes in the deposition rate and metallurgical features of the alloys induced by the change in plating parameters are discussed, based on electrochemical polarization data and the formation enthalpy of the nickel and cobalt borides.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003233715362
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  • 8
    Digitale Medien
    Digitale Medien
    Direct gene delivery into isolated microspores of rapeseed (Brassica napus L.) and the production of fertile transgenic plants (1998)
    Springer
    Plant cell reports 17 (1998), S. 323-328 
    Details
    ISSN: 1432-203X
    Schlagwort(e): Key wordsBrassica napus ; Microspore culture ; Transgenic plant ; Particle bombardment ; Doubled haploid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A procedure for direct gene transfer into isolated microspores of rapeseed (Brassica napus L.) and the production of fertile transgenic plants is presented. By modifying the microspore culture method and adopting the firefly luciferase (Luc) gene as a non-destructive marker, we could obtain stably transformed androgenetic embryos from bombarded microspores. Luc-positive embryos were easily isolated from the large non-transformed population using a high-sensitivity bioluminescent image analyzer. PCR and Southern blot analyses confirmed that the introduced transgene was integrated stably into the genome of the selected embryos. Diploidized plants obtained from the haploid embryos were self-pollinated, and all of the offspring tested were Luc-positive, indicating rapid fixation of the transgene which is characteristic of doubled haploids.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002990050401
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  • 9
    Digitale Medien
    Digitale Medien
    Abnormal cell divisions in leaf primordia caused by the expression of the rice homeobox geneOSH1 lead to altered morphology of leaves in transgenic tobacco (1996)
    Springer
    Molecular genetics and genomics 251 (1996), S. 13-22 
    Details
    ISSN: 1617-4623
    Schlagwort(e): Homeobox gene ; In situ hybridization ; Leaf morphology ; Transgenic tobacco
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Transgenic tobacco plants were generated carrying a rice homeobox gene,OSH1, controlled by the promoter of a gene encoding a tobacco pathogenesis-related protein (PR1a). These lines were morphologically abnormal, with wrinkled and/or lobed leaves. Histological analysis of shoot apex primordia indicated arrest of lateral leaf blade expansion, often resulting in asymmetric and anisotropic growth of leaf blades. Other notable abnormalities included abnormal or arrested development of leaf lateral veins. Interestingly,OSH1 expression was undetectable in mature leaves with the aberrant morphological features. Thus,OSH1 expression in mature leaves is not necessary for abnormal leaf development. Northern blot and in situ hybridization analyses indicate thatPR1a-OSH1 is expressed only in the shoot apical meristem and in very young leaf primordia. Therefore, the aberrant morphological features are an indirect consequence of ectopicOSH1 gene expression. The only abnormality observed in tissues expressing the transgene was periclinal (rather than anticlinal) division in mesophyll cells during leaf blade initiation. This generates thicker leaf blades and disrupts the mesophyll cell layers, from which vascular tissues differentiate. TheOSH1 product appears to affect the mechanism controlling the orientation of the plane of cell division, resulting in abnormal periclinal division of mesophyll cell, which in turn results in the gross morphological abnormalities observed in the transgenic lines.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02174339
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  • 10
    Digitale Medien
    Digitale Medien
    Hippocampal neural network model performing navigation by homing vector field adhesion to sensor map (1998)
    Springer
    Artificial life and robotics 2 (1998), S. 129-133 
    Details
    ISSN: 1614-7456
    Schlagwort(e): Hippocampal neural network ; Hebbian learning ; Phase coding ; Self-orientation ; Home-navigation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract We propose an artificial neural network model for autonomous agents, i.e., mobile robots, to learn maps of environments and acquire the ability to perform home-navigation autonomously. The networks consists of two subnetworks, each of which has a similar structure with hippocampal lamellar neuronal circuits. Hebbian learning procedures self-organize the first subnetwork to output the distributed sinusoidal activity of the cells by accumulating motor information generated during movement, and the second subnetwork to output localized activity by prototyping sensory information. These patterns represent a homing vector providing the relative coordinates of the agent from a starting point, and a place code corresponding uniquely to a point of the environment. By attaching homing vectors to the sensor map, the homing vector is associated with the sensory stimuli. Then the agents can perform home-navigation autonomously by this association.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02471169
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