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101.
195Pt-NMR evidence of a low lying non-linear excitation in the linear conductor K2Pt(CN)4Br0.33.2H2O
195Pt-NMR line shift, linewidth and relaxational behavior in the temperature range 4–120 K indicate a solitary excitation with an activation energy of about . 相似文献
102.
The structure of (CH3)3NHCdCl3 has been determined by single crystal X-ray diffraction at 174K. Phase changes around 342, 374, and 415 K have been detected by DTA and have been correlated with the dynamics of the organic groups via NMR measurements. No change of Laue symmetry has been observed between 170 and 400 K. 相似文献
103.
On target elements V, Fe and Co (natural isotopic composition) proton-induced reactions were investigated in the energy region from 12 to 45 MeV using the stacked-foil technique. The product nuclides observed were 48Cr, 49Cr, 51Cr, 48V, 46m + gSc, 47Sc and 48Sc from V, 55Co, 56Co, 57Co, 58m + gCo, 52Fe, 52m + gMn, 54Mn, 51Cr and 48V from Fe, and 56Ni, 57Ni, 56Co, 57Co, 58m + gCo, 54Mn and 56Mn from Co. The comprehensive set of excitation functions extending and improving earlier studies is compared with calculations considering equilibrium as well as preequilibrium reactions according to the hybrid model of Blann. The overall agreement between experiment and theory is good. Certain discrepancies, however, indicate the necessity to revise the hybrid model with respect to the emission of complex particles. 相似文献
104.
105.
Sulphonated bis-styryles and triazinyl-stilbenes have been investigated for cw dye laser operation. These promising new classes of laser dyes have proven to be superior to the known coumarins with respect to threshold, slope efficiency and photochemical stability. They shift the short wavelength tuning limit of the cw dye laser down to 403 nm. Broad tuning ranges of more than 4500 cm-1 and efficiencies up to 20% were found. In contrast to the coumarins these new dyes showed no photochemical degradation even at high pump power levels. 相似文献
106.
Zhu W Groen JC Kapteijn F Moulijn JA 《Langmuir : the ACS journal of surfaces and colloids》2004,20(13):5277-5284
Adsorption equilibria of butane isomers and SF6 on Kureha activated carbon were investigated using the volumetric method and the tapered element oscillating microbalance (TEOM) technique. The isotherm data of the butane isomers measured by the TEOM technique are in good agreement with those determined by the volumetric method. Single-component adsorption isotherms are reported at temperatures in the range from 298 to 393 K and at pressures up to 120 kPa. SF6 molecules are mainly adsorbed in the larger micropores, resulting in a lower adsorption capacity. The amount adsorbed for n-butane is slightly higher than that for isobutane in the whole range investigated. This is attributed to the fact that the linear n-butane molecule can adsorb in the smaller micropores. The T6th model appropriately describes the equilibrium data of the butane isomers, while the isotherm data of SF6 can be fitted by the Langmuir model. The isosteric heats associated with adsorption for these three adsorptives show different loading dependences. The present study indicates that the activated carbon can be well characterized by the probe molecules having different molecular sizes. 相似文献
107.
Freek Ariese Kees Swart Roberto Morabito Claudia Brunori Stefania Balzamo Jaroslav Slobodnik 《International journal of environmental analytical chemistry》2013,93(11-12):751-770
Fly ash is produced in massive quantities by fossil fuel based power plants and waste incinerators, and contains high levels of potentially toxic chemicals. Various leaching tests exist to determine the available fractions, but the outcome is strongly dependent on the experimental conditions, and these have not yet been harmonised at the international level. In order to test existing protocols for heavy metals, several intercomparisons were organised within the framework of an EU-INCO project "ANALEACH", in which seven institutes from five countries participated. Two existing reference materials were made available for the project and test batches of two new fly ash reference materials were produced. Availability tests, leaching tests and pH-stat tests were studied and critical steps in the procedures were identified. Fly ashes can also contain large amounts of inorganic sulphur and nitrogen compounds, and the determination and leaching behaviour of these compounds were also studied. In one intercomparison for metals, inorganic S and N-compounds were also included. A five-step leaching test was optimised for fly ash in order to link metal fractions to different types of binding. Column leaching experiments were carried out to investigate leaching from fly ash into soil, mimicking the effects of (acid) rain on fly ash deposited on topsoil after atmospheric transport. The major fraction of the leached metal ions was retained by the soil. Also large numbers of organic compounds (including many toxic ones) were identified in fly ash extracts, especially in city waste incinerator ash. Leaching procedures based on ultrasonic extraction were developed for organic compounds and an intercomparison exercise was organised. In a field study at the river Nitra(Slovakia) numerous organic pollutants were found at elevated levels downstream from a major fly ash dump site. 相似文献
108.
Alberto Baggioli Stefano V. Meille Guido Raos Riccardo Po Martin Brinkmann Antonino Famulari 《International journal of quantum chemistry》2013,113(18):2154-2162
In existing poly(3‐alkylthiophenes) atomistic models, an extended conformation of the side chain is usually assumed. We report a first principle study of the side‐chain energetics of 3‐hexylthiophene, with the constraint of compatibility with crystal packing requirements. The first two torsion angles of the side chain closest to the ring were considered. Electron correlation is shown to be of great relevance in the assessment of the relative stability of folded conformers against extended ones. The roles of local charge‐transfer, rehybridization, steric repulsion, and basis set superposition error, were all considered in the rationalization of our results. We extend our analysis to the thiophene/methane complex in order to elucidate the main differences between intermolecular and intramolecular CH/π phenomena. While in the noncovalent complex a single C—H bond mediates the interaction, folded arrangements of 3‐alkylthiophenes require the collective effort of several aliphatic bonds. © 2013 Wiley Periodicals, Inc. 相似文献
109.
S. Abd El-Samad R. Bilger K. -Th. Brinkmann H. Clement M. Dietrich E. Doroshkevich S. Dshemuchadse A. Erhardt W. Eyrich A. Filippi H. Freiesleben M. Fritsch R. Geyer A. Gillitzer J. Hauffe D. Hesselbarth R. Jaekel B. Jakob L. Karsch K. Kilian H. Koch J. Kress E. Kuhlmann S. Marcello S. Marwinski R. Meier K. Möller H. P. Morsch L. Naumann E. Roderburg P. Schönmeier M. Schulte-Wissermann W. Schroeder M. Steinke F. Stinzing G. Y. Sun J. Wächter G. J. Wagner M. Wagner U. Weidlich A. Wilms S. Wirth G. Zhang P. Zupranski 《The European Physical Journal A - Hadrons and Nuclei》2006,30(2):443-453
The single-pion production reactions pp → dπ+, pp → npπ+ and pp → ppπ0 were measured at a beam momentum of 0.95GeV/c ( T
p ≈ 400MeV) using the short version of the COSY-TOF spectrometer. The implementation of a central calorimeter provided particle
identification, energy determination and neutron detection in addition to time-of-flight and angle measurements. Thus, all
pion production channels were recorded with 1-4 overconstraints. The total and differential cross-sections obtained are compared
to previous data and theoretical calculations. Main emphasis is put on the discussion of the ppπ0 channel, where we obtain angular distributions different from previous experimental results, however, partly in good agreement
with recent phenomenological and theoretical predictions. In particular, we observe very large anisotropies for the π0 angular distributions in the kinematical region of small relative proton momenta revealing there a dominance of proton spinflip
transitions associated with π0
s and d partial waves and emphasizing the important role of π0
d-waves. 相似文献
110.