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  • 1
    Electronic Resource
    Electronic Resource
    Optimization of PWM technique with partially constant modulating waves (2000)
    Springer
    Electrical engineering 82 (2000), S. 263-272 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Übersicht Im vorliegenden Aufsatz wird die Qualität der Wellenformen sowie die Charakteristik des Gewinns an Spannung für den Bereich der Supramodulation in Falle der Pulsbreitenmodulationstechnik (PWM) mit partiell konstanten Modulationssignalen studiert. Auf diese Weise wird die Kommutationsanzahl in einem Dreiphasen-Wechselrichter um 33 verringert im Vergleich zur klassischen PWM-Methode. Vorgeschlagen wird eine PWM-Variante, bei der im Winkelbereich von π/3 nur zwei Kommutationen der Halbleitervorrichtungen im Wechselricher durchgeführt werden. Diese Methods unterscheidet sich von den in der bisherigen Literatur beschriebenen Methoden, da diese die notwendigen Korrekturen der Ausgangsspannung zur Verringerung der Amplituden der im Ausgangsspannungspektrum auftretenden kleinen Harmonischen absichern. Diese Korrekturen eliminieren die durch die Diskontinuitäten der Modulationswelle erzeugten unerwünschten Effekte.
    Notes: Contents In this paper the waveform quality and overmodulation region voltage-gain characteristic of pulsewidth-modulation (PWM) method with partially constant modulating waves are investigated. Thus the number of switchings in the three-phase inverter decreases by 33 as compared to the classical methods. A PWM version is proposed, in which during an interval of π/3 intervals only two switchings of the inverter semiconductor devices are performed. This method is different to those known in literature because it assure the necessary corrections of PWM-voltage in order to decrease the inverter output low order harmonics amplitudes voltages. These corrections eliminate the undesirable effects of the modulation wave discontinuities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002020000043
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  • 2
    Electronic Resource
    Electronic Resource
    Hypothesis regarding a membrane-associated mechanism of biological action due to low-dose ionizing radiation (2000)
    Springer
    Radiation and environmental biophysics 39 (2000), S. 189-195 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract  A novel theory is proposed regarding the action of ionizing radiation in the range of very low doses. The basic premise of the theory presented is that the low-dose effect cannot be explained by direct damage to the DNA (as has generally been assumed) and that effects on cellular membranes should be considered instead. Low-dose radiation damaging the plasma membrane decreases the concentration of low-molecular weight compounds (LMWC) inside the cell, which through an unspecific mechanism induces an activation of all enzymes. The mechanism described here has been well substantiated. The changes in the intracellular contents of LMWC and the increase of pHin cause chromatin rearrangements, alterations in DNA folding and finally, if the latter are strong enough, expression of various ”silent” genes including repair enzyme genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004110000061
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  • 3
    Electronic Resource
    Electronic Resource
    Valency Changes of Iron and Tin in Framework-Substituted Molecular Sieves Investigated by in Situ Mössbauer Spectroscopy (2000)
    Springer
    Journal of radioanalytical and nuclear chemistry 246 (2000), S. 143-148 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Valency changes of iron and tin in framework-substituted microporous and mesoporous molecular sieves (Fe-ETS-10, Fe-ZSM-5, Fe-AlPO-11, Sn-ZSM-12 and Sn-MCM-41) have been studied under reducing and oxidizing conditions by in situ Mössbauer spectroscopy. It is demonstrated that the structure of the host matrices strongly influences the stabilization and the oxidation state of the ions. Debye temperature, ΘD, data also are estimated, they support the suggested structural assignment of various species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006718106583
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  • 4
    Electronic Resource
    Electronic Resource
    Thermoluminescence and fluorescence study of changes in Photosystem II photochemistry in desiccating barley leaves (2000)
    Springer
    Photosynthesis research 65 (2000), S. 29-40 
    Details
    ISSN: 1573-5079
    Keywords: desiccation ; oxygen evolving complex ; relative water content ; thermoluminescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An effect of desiccation (a decrease of relative water content from 97% to 10% within 35 h) on Photosystem II was studied in barley leaf segments (Hordeum vulgare L. cv. Akcent) using chlorophyll a fluorescence and thermoluminescence (TL). The O-J-I-P fluorescence induction curve revealed a decrease of FP and a slight shift of the J step to a shorter time with no change in its height. The analysis of the fluorescence decline after a saturating light flash revealed an increased portion of slow exponential components with increasing desiccation. The TL bands obtained after excitation by continuous light were situated at about –27°C (Zv band – recombination of P680+QA −), –14 °C (A band – S3QA −), +12 °C (B band – S2/3QB −) and +45 °C (C band – TyrD+QA −). The bands related to the S-states of oxygen evolving complex (A and B) were reduced by desiccation and shifted to higher and lower temperatures, respectively. In accordance with this, the band observed at about +27 °C (S2QB −) after excitation by 1 flash fired at –10 °C and band at about +20 °C (S2/3QB −) after 2 flashes decreased with increasing water deficit and shifted to lower temperatures. A new band around 5 °C appeared in both regimes of TL excitation for a relative water content of under 42% and was attributed to the Q band (S2QA −). It is suggested that under desiccation, an inhibition of the formation of S2- and S3-states in OEC occurred simultaneously with a lowering of electron transport on the acceptor side of PS II. The temperature down-shift of the TL bands obtained after the flash excitation was induced at the initial phases of water stress, indicating a decrease of the activation energy for the S2/3QB −recombination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006472129684
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  • 5
    Electronic Resource
    Electronic Resource
    The Arabidopsis splicing factor SR1 is regulated by alternative splicing (2000)
    Springer
    Plant molecular biology 42 (2000), S. 571-581 
    Details
    ISSN: 1573-5028
    Keywords: SR proteins ; alternative splicing ; temperature regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The serine-arginine (SR)-rich splicing factors play essential roles in general splicing and regulate alternative splice site utilization in a concentration-dependent manner. SR1 is a plant homologue of the human general/alternative splicing factor SF2/ASF. We report here that alternative splicing regulates SR1 itself. Of the five detected SR1 transcripts only one encodes the full-length protein, while the other four are different variants of the essential arginine-serine-rich domain. The data suggest that SR1 pre-mRNA could be committed to two alternate splicing pathways. One, dependent on the alternative utilization of competing 3′ splice sites in intron 9, generates SR1, SR1B and SR1C. The other, regulated by suppression of intron 9 5′ splice site utilization, generates SR1D and SR1E. The splicing pattern and molecular structure of SR1D indicates an evolutionary conservation of splicing-based regulation between plants and vertebrates and suggests that the various isoforms perform important functions. Results from transient gene expression assays indicate that alternative splicing is not an autoregulatory mechanism used to control the transcript level of the full-length protein. The ratio of SR1/SR1B transcripts, which are generated by alternative 3′ splice site utilization in intron 9, is under temperature control. The temperature-dependent increase in SR1B/SR1 ratio suggests a role of SR1B in the adaptation to high-temperature environments. In addition, based on the regulated co-expression of SR1 transcripts, it is possible that some SR1 functions could be determined by the combinatorial action of the various isoforms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006394207479
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  • 6
    Electronic Resource
    Electronic Resource
    “Initialization” using an iterative Matsuno style scheme in the Eta Model adjustment stage (2000)
    Springer
    Meteorology and atmospheric physics 75 (2000), S. 121-130 
    Details
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary  Following a recent approach of Fox-Rabinovitz an iterative Matsuno or a “Super-Matsuno” style scheme is applied as a filter in the Eta Model. In contrast to Fox-Rabinovitz, we however apply the scheme not for all of the model’s time-differencing but for its adjustment terms only. These distinctions compared to the original Fox-Rabinovitz’-method are made easy to implement by the split time differencing approach of the Eta, and at the same time would appear clearly appropriate for the “initialization” purpose. In addition, while Fox-Rabinovitz emphasizes the use of the method within a long time-scale data assimilation framework, we are focusing on the impact of the method in a short-range forecasting environment/time-scale. After a short one hour “initialization” procedure is completed, standard model integration is continued, now very much free of noise. The Super-Matsuno style scheme is found to balance initially unbalanced external and internal modes and to significantly reduce the high-frequency noise during the first 6 time steps. In a control case noise also reduces in amplitude as integration proceeds, but at a much slower rate. The model integration results with and without “initialization” after 6 hours are however very similar. Even so, it is to be expected that small differences, given that they have resulted from the removal of spurious initial noise, have to be beneficial.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007030070019
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  • 7
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    Effects of uncontrolled particulate matter release on precipitation under warfare conditions (2003)
    Springer
    Details
    Publication Date: 2003-03-01
    Print ISSN: 0944-1344
    Electronic ISSN: 1614-7499
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by Springer
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  • 8
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    Effects of residential radon on cancer incidence (2003)
    Springer
    Details
    Publication Date: 2003-12-01
    Print ISSN: 0236-5731
    Electronic ISSN: 1588-2780
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Published by Springer
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  • 9
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    Wandzura-Wilczek-type relations of ρ-meson wave functions (2001)
    Springer
    Details
    Publication Date: 2001-05-16
    Print ISSN: 1126-6708
    Electronic ISSN: 1029-8479
    Topics: Physics
    Published by Springer
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  • 10
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    Synthetic Multifunctional Pores with External and Internal Active Sites for Ligand Gating and Noncompetitive Blockage (2004)
    American Chemical Society
    Details
    Publication Date: 2004-10-01
    Print ISSN: 0002-7863
    Electronic ISSN: 1520-5126
    Topics: Chemistry and Pharmacology
    Published by American Chemical Society
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