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  • 21
    Digitale Medien
    Digitale Medien
    Studies in the embryology of the diandrous orchidCypripedium cordigerum (Cypripedieae, Orchidaceae) (1988)
    Springer
    Plant systematics and evolution 160 (1988), S. 159-168 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Orchidaceae ; Cypripedieae ; Cypripedium cordigerum ; Embryology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The anther wall layers ofCypripedium cordigerum are six to eight. The glandular tapetum is 2- or 3-layered and its cells are uninucleate. Simultaneous cytokinesis results in decussate, isobilateral and tetrahedral pollen tetrads. Ripe pollen grains are 2-celled. The mature ovules are anatropous, bitegmic and tenuinucellate. Both the integuments are dermal in origin and 2-layered. The inner integument alone forms the micropyle. The female gametophyte is 6-nucleate and bisporic. The reduction of nuclei is due to the “strike” phenomenon. Double fertilization occurs. The primary endosperm nucleus divides to form two free endosperm nuclei. The mature embryo is undifferentiated. The cells ca, m and n contribute to the embryo. The suspensor is single-celled. The seed coat is formed entirely by the outer layer of the outer integument. There are three sterile and three fertile valves in the ovary. In the prefertilization stages these valves consist of parenchymatous cells with starch and raphides. After fertilization, the sterile valves develop sclerotic cells whereas the fertile valves remain parenchymatous. The pericarp structure and embryological features support the retention of tribeCypripedieae within theOrchidaceae.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00936043
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  • 22
    Digitale Medien
    Digitale Medien
    Thermoelectric power studies of Sn/Nb substituted Mn-Zn ferrites (1999)
    Springer
    Journal of materials science 34 (1999), S. 621-623 
    Details
    ISSN: 1573-4803
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract Thermoelectric power studies of polycrystalline materials of Sn/Nb substituted Mn-Zn ferrites have been carried out. The Seebeck coefficient, carrier concentration and drift mobility were evaluated. The Seebeck coefficient increases up to 420 K and 400 K for Nb and Sn substituted ferrites respectively. All the ferrites exhibited n-type conduction over the range of temperature studied. At high temperatures, a non-degenerate type of semiconductor behaviour has been observed. The conduction of these materials is explained by hopping of electrons from Fe2+ to Fe3+, in addition to the existence of narrow bands and localized levels. The variation of drift mobility is explained by wavy bands [1, 2].
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004571418384
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  • 23
    Digitale Medien
    Digitale Medien
    Effects of deposition and annealing conditions on the structure and electrical properties of LPCVD silicon thin films (2000)
    Springer
    Journal of materials science 35 (2000), S. 4743-4746 
    Details
    ISSN: 1573-4803
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract Deposition temperature and annealing conditions have pronounced effects on the structure and electrical properties of LPCVD silicon thin films. Films grown at 580°C are amorphous whereas those grown at 620°C are microcrystalline. All thin films are subjected to phosphorous diffusion followed by different annealing treatments. Annealing of amorphous films at 1000°C results in large grains with no favoured orientation and with a relatively high mobility value. Annealing treatment at 1000°C of the microcrystalline sample results in moderate grain growth with a relatively low mobility which presumably is due to some favoured grain orientation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004867410373
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  • 24
    Digitale Medien
    Digitale Medien
    Copolymerization reactivity ratios of N,N-dimethyl acrylamide and isopropyl methacrylate determined by 1H-NMR spectroscopy (1991)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 192 (1991), S. 51-55 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: N,N-Dimethylacrylamid (DMA) und Isopropylmethacrylat (IPM) wurden in Dimethylformamid mit Azoisobutyronitril als Initiator copolymerisiert. Die Copolymerzusammensetzung wurde 1H-NMR-spektroskopisch ermittelt. Die Copolymerisationsparameter (rDMA = 0,58, rIPM = 2,76) wurden nach Kelen-Tüdős berechnet.
    Notizen: Copolymers of N,N-dimethyl acrylamide (DMA) and isopropylmethacrylate (IPM) were prepared in dimethyl formamide using azoisobutyronitrile as initiator. The composition of copolymers was determined by 1H-NMR analysis. Reactivity ratios (rDMA = 0.58, rIPM = 2.76) were calculated from these values by using the Kelen-Tüdős differential linear equation.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1991.051920104
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  • 25
    Digitale Medien
    Digitale Medien
    Radioactivity in monitoring materials processing (1996)
    Springer
    Journal of radioanalytical and nuclear chemistry 203 (1996), S. 519-535 
    Details
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract Monitoring of the concentration of actinides in process streams and waste materials can be effectively carried out by detecting and measuring their radioactive emissions. Such monitoring techniques lead to more efficient control of the process, and also aid in the minimisation of losses to the waste and better accounting of the nuclear materials. This paper provides an overview of some of the techniques such as on-line alpha monitoring, passive and active neutron assay and gamma counting, and also describes the monitoring systems which have been developed in our laboratory for use in a reprocessing plant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02041527
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  • 26
    Digitale Medien
    Digitale Medien
    Trace analysis of mercury by a radiochemical displacement method using cobalt(III) diethyldithiocarbamate (1988)
    Springer
    Journal of radioanalytical and nuclear chemistry 120 (1988), S. 155-159 
    Details
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract A radiochemical displacement method was utilized for the determination of traces of mercury in water taking advantage of its ability to displace cobalt from cobalt(III) diethyldithiocarbamate tagged with60Co. The method is found to be applicable in the concentration range of 50–200 μg/ml mercury. The interfernces from various cations like Fe(III), Co(II), Cu(II), Pb(II) and Ag(I) ions were studied.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02037862
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  • 27
    Digitale Medien
    Digitale Medien
    Extraction of nitric acid by some trialkyl phosphates (1997)
    Springer
    Journal of radioanalytical and nuclear chemistry 222 (1997), S. 231-234 
    Details
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract The extraction of nitric acid by tri-n-butyl phosphate (TBP), tri-sec-butyl phosphate (TsBP) and tri-iso-amyl phosphate (TiAP) solutions in n-dodecane are reported. The results indicate that increase in carbon chain length of the alkyl group of the phosphate as well as introduction of branching near the phosphoryl (P=O) group of the phosphate do not affect significantly the extraction of nitric acid.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02034276
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  • 28
    Digitale Medien
    Digitale Medien
    Sorption of heavy metals by four basidiomycetous fungi (1995)
    Springer
    Bioprocess engineering 12 (1995), S. 273-277 
    Details
    ISSN: 0178-515X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract  Biosorptions of Pb2+, Cr6+, Cd2+ and Ni2+ were investigated, with special emphasis on the first one, using live and dead fungal mycelia. Of the four fungi, namely Polyporus ostreiformis, Volvariella volvacea, Pleurotus sajor-caju and Phanerochaete chrysosporium, the last one was found to be most effective in Pb2+ removal. Total biosorption was effected in 6 days up to the Pb2+ concentration of 6 mg/l, with a specific uptake of 1.33 mg Pb2+/g dry cell mass. The removal of other three metals varied between 28.8–73.3% from a medium containing 4 mg/l of each of the metals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00369502
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  • 29
    Digitale Medien
    Digitale Medien
    A spectrophotometric method for the determination of the oxygen to metal ratio in U3O8 (1994)
    Springer
    Journal of radioanalytical and nuclear chemistry 188 (1994), S. 463-470 
    Details
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract A fast and accurate method for the determination of oxygen to metal ration (O/M) in U3O8 is described. The method involves dissolution of the sample in 85% phosphoric acid containing sulfate ions and measurement of the U(IV) absorbance directly and after reducing the U(VI) in the sample to U(IV) with Fe(II). The O/M is calculated from the ratio of the two absorbances. Elaborate calibrations for U(IV) and U(VI) are avoided and the sample requirement is a minimum. The method gives the oxygen to metal ratio with an accuracy better than ±0.004 O/M units and precision better than ±0.004 O/M units.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02164739
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  • 30
    Digitale Medien
    Digitale Medien
    Quantitative separation of carrier-free cerium from fission products (1996)
    Springer
    Journal of radioanalytical and nuclear chemistry 214 (1996), S. 17-27 
    Details
    ISSN: 1588-2780
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik
    Notizen: Abstract The extraction of Ce (IV) by di-(2-ethylhexyl)-phosphoric acid (HDEHP) has been studied as a function of nitric acid concentration. Using the distribution coefficient data, the optimum conditions for recovery of Ce (IV) from nitric acid medium were arrived at. Under the conditions employed for Ce(IV), a small percentage of Ru was also found to be extracted. Cerium could be selectively stripped from the organic phase with 8M HNO3/30% H2O2 solution. This procedure led to the recovery of144Ce free of106Ru. Based on the solvent extraction data, an extraction-chromatographic procedure employing HDEHP (40% w/w) loaded on Amberlite XAD-7 as the stationary phase was developed for the isolation of pure, carrier-free144Ce from the spent fuel solution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02165055
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