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  • 1
    Electronic Resource
    Electronic Resource
    Elastic and dynamic properties of polymer electrolytes: A Brillouin scattering study of poly(propylene glycol)–NaCF3SO3 complexes (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 655-662 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In the present study of ion conducting polymers we demonstrate how light scattering can be used to obtain information about the elastic properties and the local intrachain mobility, which are essential characteristics of a high performance polymeric solid electrolyte. Brillouin scattering has been applied in studies of sodium triflate (NaCF3SO3)–poly(propylene glycol) (PPG) complexes of concentrations O:M=5:1, 8:1, and 16:1, where O:M is the backbone oxygen to sodium ratio. From the spectra sound velocity and absorption data were obtained. The acoustic data reveal structural relaxation processes associated with local translational (and orientational) intrachain motions of the polymer segments. The characteristic relaxations times τ were determined and found to be strongly dependent on the concentration of the dopant salt. This is because the dissociated ions act both as crosslinks betwen polymer chain segments and as "free'' ions available for conduction. Therefore, as the concentration of dissociated ions increases the intrachain mobility is slowed down (τ increases) due to increased crosslinking. The effect is demonstrated in the hypersonic velocity dispersion curve and in the absorption peak which both shift to higher temperatures with increasing salt concentration. The shift correlates with the increase in the glass transition temperature as salt is added to the polymer. It also correlates, at least at low salt concentrations, with the concentration of dissocated ions and with the conductivity. It can be concluded that the motions of free ions responsible for charge transport are strongly coupled to the intrachain motions of the polymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457171
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  • 2
    Electronic Resource
    Electronic Resource
    Elastic and dynamic properties of a poly(propylene glycol)-lithium perchlorate electrolyte: a brillouin scattering study (1990)
    s.l. : American Chemical Society
    Macromolecules 23 (1990), S. 163-167 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00203a028
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of cobalt substitution on the thermal diffusivity of YBa2Cu3O7−δ superconductor (1997)
    Springer
    Journal of superconductivity and novel magnetism 10 (1997), S. 663-668 
    Details
    ISSN: 1557-1947
    Keywords: Thermal diffusivity ; acoustic plasmons ; cobalt substitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The thermal diffusivity κ(T) of the cobalt-substituted sintered YBCO system, YBa2Cu3−x Co x O7∮δ (x=0.0, 0.1), has been measured to, investigate, effects of atomic substitution and charge carrier concentration on the thermal diffusion processes. The thermal diffusivity was measured in the temperature range 35–300 K, using the transient-plane-source technique. The results show that, belowT c , the κ(T) values of the doped (x=0.1), samples are lower than the corresponding values for the undoped (x=0.0) samples. This may be due to the difference in the free-charge carrier concentrations of the two samples. A decoupling between the conducting Cu−O planes as a result, of Co-doping in the chain sites may contribute to additional decrease in the thermal diffusivity of the doped sample. An attempt was made to explain the rise in the thermal diffusivity belowT c by adopting a recent theoretical model based on the existence of weakly damped collective electron excitations of Bose type, with acoustic dispersion relation, (acoustic plasmons) inside the superconducting gap.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02471929
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  • 4
    Electronic Resource
    Electronic Resource
    Superconducting gap in Pr x Y1−x Ba2Cu4O8 and YBa2−y Sr y Cu4O8 probed by infrared phonon self-energies (1994)
    Springer
    Journal of superconductivity 7 (1994), S. 113-116 
    Details
    ISSN: 1572-9605
    Keywords: High-temperature superconductivity ; superconducting gap ; phonons ; reflectivity spectra ; alloys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract We report a reflectivity study of thez-polarized TO-phonons of Pr x Y1−x Ba2Cu4O8 and YBa2−y Sr y Cu4O8 alloys in the temperature range 10–300 K. Anomalies of the frequency and linewidth of the plane-oxygen vibration atω∼300 cm−1 due to the opening of the superconducting gap are found to occur upon crossing the superconducting transition temperatureT c . Phonon self-energy effects are strongly dependent onT c , providing evidence for a relative shift of the gap with respect to the energy of phonon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00730379
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  • 5
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of triazolam in geriatric patients (1983)
    Springer
    European journal of clinical pharmacology 25 (1983), S. 91-94 
    Details
    ISSN: 1432-1041
    Keywords: triazolam ; geriatric patients ; hypnotics ; pharmacokinetics ; plasma concentration ; benzodiazepine ; alpha-hydroxytriazolam
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Serum triazolam levels were determined in eight geriatric patients (average age 80 years) on Days 1 and 7 of administration of triazolam 0.25 mg once daily, 1 h after a standard breakfast. Triazolam was rapidly absorbed reaching average peak concentrations of 2.0 and 2.04 ng/ml, 1.5 and 1.38 h after administration on Days 1 and 7, respectively. The mean apparent elimination half-life was 1.41 h (range 0.73–4.13 h) on Day 1 and 1.37 h (range 0.69–3.36 h) on Day 7. There was no significant difference between mean serum triazolam concentrations or pharmacokinetic parameters on Days 1 and 7 of the treatment. Serum samples were also assayed for α-hydroxytriazolam, an active metabolite of triazolam, but none could be detected in any of the samples from Days 1 or 7, assay sensitivity 0.09 ng/2 ml serum. The range of half-lives of triazolam in the patients in the present study is in close agreement with that previously reported in elderly subjects. The study provides further evidence of the lack of change in pharmacokinetic parameters on multiple dosing and that drug accumulation did not occur.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00544022
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  • 6
    Electronic Resource
    Electronic Resource
    The Effects of Cobalt Substitution on the Thermal Diffusivity of YBa2Cu3O7−δ Superconductor (1997)
    Springer
    Journal of superconductivity 10 (1997), S. 663-668 
    Details
    ISSN: 1572-9605
    Keywords: Thermal diffusivity ; acoustic plasmons ; cobalt substitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The thermal diffusivity κ(T) of the cobalt-substituted sintered YBCO system, YBa2Cu3−x Co x O7−δ (x=0.0, 0.1), has been measured to investigate effects of atomic substitution and charge carrier concentration on the thermal diffusion processes. The thermal diffusivity was measured in the temperature range 35–300 K using the transient-plane-source technique. The results show that, below T c, the κ(T) values of the doped (x=0.1) samples are lower than the corresponding values for the undoped (x=0.0) samples. This may be due to the difference in the free-charge carrier concentrations of the two samples. A decoupling between the conducting Cu–O planes as a result of Co-doping in the chain sites may contribute to additional decrease in the thermal diffusivity of the doped sample. An attempt was made to explain the rise in the thermal diffusivity below T c by adopting a recent theoretical model based on the existence of weakly damped collective electron excitations of Bose type, with acoustic dispersion relation (acoustic plasmons) inside the superconducting gap.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022662514542
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  • 7
    Electronic Resource
    Electronic Resource
    Investigation of the temperature dependence of electron and phonon Raman scattering in single crystal YBa2Cu3O6.952 (1994)
    Springer
    Journal of superconductivity 7 (1994), S. 445-448 
    Details
    ISSN: 1572-9605
    Keywords: Raman scattering ; electron-phonon coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Detailed Raman-scattering measurements have been performed on high-quality YBa2Cu3O6.952 single crystal (T c =93 K, ΔT c =0.3 K). A sharp (FWHM 7.2 cm−1 at 70 K and 10.0 cm−1 at 110 K) 340 cm−1phonon mode has been observed inB 1g polarization. An electronic scattering peak at 500 cm−1 in theB 1g polarization extends down to 250 cm−1. These FWHM values determine the upper limit of the homogeneous linewidth of the phonon and electronic excitations. The start of the electronic spectral function renormalization and of the 340 cm−1 mode anomalies (frequency softening, linewidth sharpening, and intensity increase) have been observed to occur approximately 40 K aboveT c . The 340 cm−1 mode Fano shape analysis has been performed and the temperature dependences of the Fano shape parameters have been estimated. All 340 cm−1 mode anomalies have been explained by the electronic spectral function renormalization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00724586
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  • 8
    Electronic Resource
    Electronic Resource
    A neutron and x-ray diffraction investigation of intermediate range structure in silver borate glasses (1995)
    Springer
    Ionics 1 (1995), S. 101-105 
    Details
    ISSN: 1862-0760
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The ion diffusion mechanism in ion conducting glasses has in many reports been suggested to be linked to the structure. However, in most cases the structures of the glasses are not very well known. We have investigated the structure of the glass system (AgI)x (Ag2O-2B2O3)1−x, with x=0, 0.6 by neutron and x-ray diffraction experiments. AgI doping produces an intense peak in the neutron data at an anomalously low Q-value (0.8 Å−1) that indicates increased intermediate range ordering. Only a weak peak is observed at a similar Q-value in the x-ray structure factor. By comparing the different neutron and x-ray weighting factors the origin of the anomalous peak is unambiguously attributed to correlations within the B-O network. The experimental results have been used to model the glasses by Reverse Monte Carlo simulations to obtain more detailed views of the structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02388665
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  • 9
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    Seasonal dynamics of the soil microbial community: assimilation of old and young carbon sources in a long-term field experiment as revealed by natural 13C abundance (2015)
    Wiley-Blackwell
    Details
    Publication Date: 2015-11-24
    Description: Microbial biomass is a small part of the total soil organic carbon (SOC) pool, but plays a major role in its turnover. A field experiment in Sweden, amended with different mineral and organic materials since 1956, was changed from continuous C3 plants to C4 vegetation (silage maize) in 2000. In 2012, soil samples from three fertilizer treatments (calcium nitrate, calcium nitrate plus straw and sewage sludge) and two controls (bare fallow and cropped unfertilized) were taken on three occasions (before, during and after cropping). Phospholipid fatty acids (PLFAs) were extracted from all soil samples and analysed for 12 C and 13 C contents in individual PLFAs. Seasonal variation in total PLFAs was small except for the most SOC-rich treatment (sewage sludge). Weighted means of δ 13 C in PLFAs showed that the plots fertilized with calcium nitrate only had the largest δ 13 C values in PLFAs before (−20.24‰) and after the vegetation period (−20.37‰). However, during the vegetation period the values were much smaller (−21.85‰). This coincided with a strong increase in the PLFA 18:2ω6,9, indicating the use of old organic matter by fungi. Monounsaturated PLFAs indicative of Gram-negative bacteria were more frequent before and after the growing season. This observed ‘rebound’ effect of the δ 13 C PLFA values during the vegetation period indicates that seasonal turnover of the microbial biomass can be substantial.
    Print ISSN: 1351-0754
    Electronic ISSN: 1365-2389
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Wiley-Blackwell
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  • 10
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    Identification and quantification of organic phosphorus forms in soils from fertility experiments (2013)
    Wiley-Blackwell
    Details
    Publication Date: 2013-03-06
    Description: The effects of soil type, crop rotation, fertilizer type and application rate on the composition of organic phosphorus (P) compounds in soils from four sites in a Swedish long-term fertilizer experiment were investigated with 31 P-NMR. Soil textures investigated were loamy sand, sandy loam, silty clay loam and clay. Phosphorus has been added to the soils since the 1950s and 1960s at four different rates in the form of either mineral fertilizer or a combination of manure and mineral fertilizer. Results show that in soils receiving no P addition, most of the soil P was present in the form of phosphate monoesters (60–70%, depending on soil type). However, a P addition equivalent to the amount of P removed annually by harvest altered this relationship so that the soils were dominated by orthophosphate instead. This trend became more obvious with increasing P addition. At the greatest P application rate, orthophosphate comprised 70% or more of the total extracted P in all the soils. These changes in the soil were due entirely to increase in orthophosphate, because the amounts of monoesters did not change with increasing P additions. This was true both for mineral fertilizer and the combination of manure and mineral fertilizer P. Soil type and crop rotation did not influence the results. The results indicate that there is no apparent build-up of organic P in the soils, but that P addition mainly affects the orthophosphate amounts in the soils regardless of form or amount of fertilizer.
    Print ISSN: 0266-0032
    Electronic ISSN: 1475-2743
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Published by Wiley-Blackwell
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