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  • 1
    Digitale Medien
    Digitale Medien
    Downward flux of water through roots (i.e. inverse hydraulic lift) in dry Kalahari sands (1998)
    Springer
    Oecologia 115 (1998), S. 460-462 
    Details
    ISSN: 1432-1939
    Schlagwort(e): Key words Water transport ; Grass roots ; Hydraulic lift ; Deserts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Downward transport of water in roots, in the following termed “inverse hydraulic lift,” has previously been shown with heat flux techniques. But water flow into deeper soil layers was demonstrated in this study for the first time when investigating several perennial grass species of the Kalahari Desert under field conditions. Deuterium labelling was used to show that water acquired by roots from moist sand in the upper profile was transported through the root system to roots deeper in the profile and released into the dry sand at these depths. Inverse hydraulic lift may serve as an important mechanism to facilitate root growth through the dry soil layers underlaying the upper profile where precipitation penetrates. This may allow roots to reach deep sources of moisture in water-limited ecosystems such as the Kalahari Desert.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004420050541
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  • 2
    Digitale Medien
    Digitale Medien
    Maximum rooting depth of vegetation types at the global scale (1996)
    Springer
    Oecologia 108 (1996), S. 583-595 
    Details
    ISSN: 1432-1939
    Schlagwort(e): Deep roots function ; Terrestrial vegetation ; Biomes ; Plant forms ; Root depth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The depth at which plants are able to grow roots has important implications for the whole ecosystem hydrological balance, as well as for carbon and nutrient cycling. Here we summarize what we know about the maximum rooting depth of species belonging to the major terrestrial biomes. We found 290 observations of maximum rooting depth in the literature which covered 253 woody and herbaceous species. Maximum rooting depth ranged from 0.3 m for some tundra species to 68 m for Boscia albitrunca in the central Kalahari; 194 species had roots at least 2 m deep, 50 species had roots at a depth of 5 m or more, and 22 species had roots as deep as 10 m or more. The average for the globe was 4.6±0.5 m. Maximum rooting depth by biome was 2.0±0.3 m for boreal forest. 2.1±0.2 m for cropland, 9.5±2.4 m for desert, 5.2±0.8 m for sclerophyllous shrubland and forest, 3.9±0.4 m for temperate coniferous forest, 2.9±0.2 m for temperate deciduous forest, 2.6±0.2 m for temperate grassland, 3.7±0.5 m for tropical deciduous forest, 7.3±2.8 m for tropical evergreen forest, 15.0±5.4 m for tropical grassland/savanna, and 0.5±0.1 m for tundra. Grouping all the species across biomes (except croplands) by three basic functional groups: trees, shrubs, and herbaceous plants, the maximum rooting depth was 7.0±1.2 m for trees, 5.1±0.8 m for shrubs, and 2.6±0.1 m for herbaceous plants. These data show that deep root habits are quite common in woody and herbaceous species across most of the terrestrial biomes, far deeper than the traditional view has held up to now. This finding has important implications for a better understanding of ecosystem function and its application in developing ecosystem models.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00329030
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  • 3
    Digitale Medien
    Digitale Medien
    Vibrational and electronic properties of tris(8-hydroxyquinolinato)vanadium (III) (1989)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 20 (1989), S. 555-560 
    Details
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: A study of the electronic, infrared, Raman and pre-resonace Raman spectra of the solid complex tris(8-hydroxyquinolinato)vanadium(III) was performed. The excitation profiles of the vibrational modes that show preresonance on excitation with laser lines within the electronic bands in the visible region are reported and, on this basis and molecular orbital calculations, several vibrational and electronic absorption bands were assigned.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jrs.1250200902
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  • 4
    Digitale Medien
    Digitale Medien
    Surface-enhanced Raman scattering of 4-picolylamine and its [Fe(CN)5]n- complexes (1991)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 22 (1991), S. 301-305 
    Details
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The SER spectra of the complexes [Fe(CN)5(4-picolylamine)]3- and [Fe2(CN)10(4-picolylamine)]6- adsorbed on a silver electrode were investigated. The analysis of the frequency shift of the CN stretching mode indicated that both molecules adsorb via one or more CN ligand groups. For potentials more positive than 0.0 V the CN stretching frequency for both complexes moves towards higher wavenumbers charcterizing the presence of Fe(III) over the surface. The SER spectra of 4-picolylamine adsorbed on a silver electrode in solutions of pH 2.8, 6.5 and 10.3 were also investigated. From the data obtained it was concluded that 4-picolylamine in solution at pH 6.5 and 10.3 adsorbs on the electrode through the nitrogen of the pyridine ring.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jrs.1250220512
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  • 5
    Digitale Medien
    Digitale Medien
    Raman and infrared spectra and photochemical behaviour of acetaldehyde isolated in matrices (1991)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 22 (1991), S. 505-507 
    Details
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: As part of a general study on the behaviour of acetaldehyde as an atmospheric pollutant, the Raman and infrared spectra are presented of acetaldehyde isolated in argon and nitrogen matrices. Using the observed frequencies, the thermodynamic functions were calculated. By obtaining the vibrational spectra at low temperature, it was possible to assess the results of the photochemical studies that have been done in matrices with both argon and nitrogen gases. The main products in the photochemical decomposition of acetaldehyde under the conditions adopted are methane and carbon monoxide.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jrs.1250220906
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  • 6
    Digitale Medien
    Digitale Medien
    Raman spectra of Br3- and I3- adsorbed on zeolites (1981)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 11 (1981), S. 320-321 
    Details
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The Raman spectra of Br3- and I3- adsorbed on several zeolites were investigated in order to verify a previous assignment of bands, observed in the spectra of bromine and iodine adsorbed on zeolites, to the trihalide ions formed in the zeolites.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jrs.1250110505
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  • 7
    Digitale Medien
    Digitale Medien
    Raman resonance excitation profile of the μ-oxobis[pentacyanomanganate (III)] ion (1987)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 18 (1987), S. 577-579 
    Details
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The resonance Raman spectra of potassium μ-oxobis[pentacyanomanganate(III)] cyanide, K7[Mn2O(CN)10]CN, were measured using exciting lines at 356.4, 406.7, 530.9, 568.2, 603.5, 647.1 and 676.4 nm. By combining these data with those obtained previously (excitations at 457.9, 476.5, 488.0, 496.5, 514.5 and 608.6 nm), the excitation profiles were plotted for three totally symmetric vibrations at 1880 (CNax strech), 527 (MnCax stretch) and 259 cm-1 (MnOMn stretch). It was found that the equation derived by Mingardi et al. can adequately express these excitation profiles and that the previous assignment of the electronic transition at 509 nm needs revision.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jrs.1250180808
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  • 8
    Digitale Medien
    Digitale Medien
    Surface-enhanced Raman scattering of the redox pair CO(sep)3+/Co(sep)2+ on silver and copper electrodes (1989)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 20 (1989), S. 725-728 
    Details
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The surface-enhanced Raman spectra of the redox pair Co(sep)3+/Co(sep)2+ (sep: sepulchrate) adsorbed on silver and copper electrodes have been obtained in the skeletal region for these compounds and the results were consistent with the redox potential of the species. The role of the anions and cations of the support electrolytes in the adsorption of the Co(sep)3+ on a silver electrode suggests that the compound is adsorbed on the electrode via ion pair formation with the anion specifically adsorbed. From the behaviour of the Raman intensity of the CH2 symmetrical stretching vibration it was possible to estimate the pKa of the Co(sep)2+.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jrs.1250201104
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  • 9
    Digitale Medien
    Digitale Medien
    Polarized Raman spectra of single-crystal barium nitroprusside trihydrate, Ba[Fe(CN)5NO]·3H2OA communication on this subject was presented at the Xth Congress and General Assembly of the IUCr, Bordeaux, France, 19-28 July 1990. (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 23 (1992), S. 131-136 
    Details
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The room-temperature polarized Raman scattering of single-crystal Ba [Fe(CN)5NO] · 3H2O, space group Pbcm (D112h, No. 57), in the 2200-10 cm-1 spectral range, and a factor group analysis of the nitroprusside anion vibrational modes are presented. The near parallelism between the anion NCFeNO axis and a crystallographic axis facilitates the interpretation of the spectra. The data obtained complement already existing IR studies and the two series of results together provide reference information for the understanding of the vibrational behaviour of the recently reported electronically excited metastable states of the anion. The Raman data confirm the existence of a relatively large correlation (Davydov) splitting between NO stretching modes due to vibrational coupling between neighbouring nitrosyl groups in the lattice.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jrs.1250230302
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  • 10
    Digitale Medien
    Digitale Medien
    The dependence of Raman intensity on the scattering frequency (1978)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 7 (1978), S. 294-296 
    Details
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Aqueous solutions of (NH4)2MoS4 have been investigated with Ar+ laser excitation, at frequencies which span the visible absorption spectrum. Enhanced values of the anti-Stokes/Stokes intensity ratios for the fundamental ν1 and overtone 2ν1 show that the Nafie et al. theory accounts satisfactorily for these observed ratios.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jrs.1250070513
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