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21.
22.
Fries KH Driskell JD Sheppard GR Locklin J 《Langmuir : the ACS journal of surfaces and colloids》2011,27(19):12253-12260
In this article, a methacrylate-based spiropyran-containing copolymer was used as a colorimetric sensor to identify multiple metal ions simultaneously. Through UV-vis absorption spectroscopy, the relative binding affinity of merocyanine to each metal ion was investigated by displacement studies of a bound metal ion with a second metal ion of a higher binding affinity. We also show that because each metal ion gives rise to a distinct spectral response, partial least-squares discriminant analysis (PLS-DA) can be used to analyze the UV-vis absorbance spectra to identify the two metal ions that are present in solution at varying concentrations simply by dipping a coated polymer substrate into solution after irradiation. Partial least-squares regression analysis (PLS) was used to determine the metal ions in solution for several binary mixtures quantitatively. We also demonstrate that the quantitative determination depends on the relative binding preference of merocyanine to each metal ion. 相似文献
23.
Gas bubbles in simulation and experiment 总被引:1,自引:0,他引:1
Lakshmanan P Peters F Fries N Ehrhard P 《Journal of colloid and interface science》2011,354(1):364-372
An experimental setup for the examination of single bubbles, rising in a liquid, is presented. Its main part is a rotating chamber, in which the bubble is spatially stabilized by a balance of buoyancy, drag, and lift forces. This allows for long observation periods in time. Experimental results are presented for air bubbles in silicone oil. The experimental results are validated by a comparison with numerical simulations. A modified, mass-conserving level-set method is used for the representation of the free interface, while an immersed-boundary formulation is engaged for the conservation equations. The agreement between experiment and simulation, and to available correlations from literature, is found to be perfect. It is shown that the influence of the liquid shear due to the rotation is negligible. Also, for the presented liquid system, no influence by Marangoni stresses could be found, which makes the system of air and silicone oil a good choice for validation purposes. 相似文献
24.
25.
26.
Göran Fries 《BIT Numerical Mathematics》1975,15(4):394-400
The paper gives a definition of compatibility, and tries to answer the question why compatibility is of great importance. The paper also suggests a solution by using multilingual techniques in the creation of the complete system. 相似文献
27.
R. Brandelik W. Braunschweig H.-U. Martyn H.G. Sander D. Schmitz W. Sturm W. Wallraff D. Cords R. Felst R. Fries E. Gadermann H. Hultschig P. Joos W. Koch U. Kotz H. Krehbiel D. Kreinick S. Yamada 《Physics letters. [Part B]》1977,67(3):358-362
Charged hadron production via has been measured for s values between 13 and 25 GeV2. Inclusive cross sections and the evidence for scaling are presented. 相似文献
28.
H.J. Behrend Ch. Chen H. Fenner J.H. Field V. Schr?der H. Sindt G. DAgostini W.D. Apel S. Banerjee J. Bodenkamp D. Chrobaczek J. Engler G. Flügge D.C. Fries W. Fues K. Gamerdinger G. Hopp F. Pierre 《Physics letters. [Part B]》1982,114(4):282-286
The e+e?→τ+τ? process has been measured using the CELLO detector at a mean total centre of mass energy of 34.2 GeV using essentially all the decay channels of the τ lepton. The measured cross section yields Rτ=1.03±0.05 (stat)±0.07 (syst). Topological branching fraction are given for τ → 1, 3 or 5 charged tracks. The angular distribution shows a clear 1 + cos2θ dependance with a forward-backward asymmetry of -0.103 ± 0.052 corresponding to an axial-vector coupling aτ of the τ to the weak neutral current given by aτ=?1.12 ± 0.57. 相似文献
29.
T. Wöhrle P. Gómez-Romero T. Fries K. West M. R. Palacín N. Casañ-Pastor 《Ionics》1996,2(5-6):442-445
The lithium ionic conducting perovskite La0.57Li0.3TiO3 has been synthesised via a sol-gel method at a temperature of 700 °C. The crystallinity of the product can be greatly increased
by further heat treatment at 1000 °C. In this paper the product of the sol-gel synthesis is compared with the product of conventional
solid-state synthesis, and the influence of the synthesis method as well as of quenching on the crystal structure and ionic
conductivity has been studied. AC-impedance measurements show two contributions to the ionic conductivity, which can be adscribed
to intergranular and intragranular effects, respectively. A lower intergranular resistivity is observed for sol-gel samples,
while quenching mainly affects the materials prepared by solid-state reaction. The crystal structure of the material prepared
by the sol-gel method is identical to that of the material prepared by the solid state reaction, although the synthesis temperature
is nearly 600 °C lower. A tetragonal superstructure is observed when either type of material is slowly cooled from 1300 °C.
Quenching from the same temperature results in the suppression of that superstructure.
Paper presented at the 3rd Euroconference on Solid State Ionics, Teulada, Sardinia, Italy, Sept. 15–22, 1996 相似文献
30.
The sensitivity and precision of headspace solid-phase micro extraction (HS-SPME) at an analyte solution temperature (T
as) of +35 °C and a fiber temperature (T
fiber) of +5 °C were compared with those for HS-SPME at T
as and T
fiber of −20 °C for analysis of the volatile organic compounds benzene, 1,1,1-trichloroethane, trichloroethylene, toluene, o-xylene, ethylbenzene, m/p-xylene, and tetrachloroethylene in water samples. The effect of simultaneous fiber cooling and analyte solution freezing
during extraction was studied. The compounds are of different hydrophobicity, with octanol/water partition coefficients (Kow) ranging from 126 and 2511. During a first set of experiments the polydimethylsiloxane (PDMS) SPME fiber was cooled to
+5 °C with simultaneous heating of the aqueous analyte solution to +35 °C. During a second set of experiments, both SPME fiber
holder and samples were placed in a deep freezer maintained at −20 °C for a total extraction time of 30 min. After approximately
2 min the analyte solution in the vial began to freeze from the side inwards and from the bottom upwards. After approximately
30 min the solution was completely frozen. Analysis of VOC was performed by coupling HS-SPME to gas chromatography-mass spectrometry
(GC-MS). In general, i.e. except for tetrachloroethylene, the sensitivity of HS-SPME increased with increasing compound hydrophobicity
at both analyte solution and fiber temperatures. At T
as of +35 °C and T
fiber of +5 °C detection limits of HS-SPME were 0.5 μg L−1 for benzene, 1,1,1-trichloroethane, trichloroethylene, and tetrachloroethylene, 0.125 μg L−1 for toluene, and 0.025 μg L−1 for ethylbenzene, m/p-xylene, and o-xylene. In the experiments with T
as and T
fiber of −20 °C, detection limits were reduced for compounds of low hydrophobicity (Kow<501), for example benzene, toluene, 1,1,1-trichloroethane, and trichloroethylene. In the concentration range 0.5–62.5 μg
L−1, the sensitivity of HS-SPME was enhanced by a factor of approximately two for all compounds by performing the extraction
at −20 °C. A possible explanation is that freezing of the water sample results in higher concentration of the target compounds
in the residual liquid phase and gas phase (freezing-out), combined with enhanced adsorption of the compounds by the cooled
fiber. The precision of HS-SPME, expressed as the relative standard deviation and the linearity of the regression lines, is
increased for more hydrophobic compounds (Kow>501) by simultaneous direct fiber cooling and freezing of analyte solution. Background contamination during analysis is
reduced significantly by avoiding the use of organic solvents. 相似文献