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51.
52.
K. Wendt S. A. Ahmad F. Buchinger A. C. Mueller R. Neugart E. -W. Otten 《Zeitschrift für Physik A Hadrons and Nuclei》1984,318(2):125-129
The collinear laser-ion beam technique has been used to measure the isotope shift and hyperfine structure in the 6s-6p doublet (4,934Å, 4,554Å) of Ba II for all seven stable isotopes. The influence of the excited2 P 1/2 and2 P 3/2 states on the field shift leads to a difference of 2.5(3)% in the electronicF factors. The specific mass shifts differ by {A′-A} 2.2(3) MHz which corresponds to about 12% of the normal mass shift. 相似文献
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Statistical heteroporosity theory is applied to the case of ultrafiltration across a membrane composed of an array of independent channels or pores. The primary question addressed is: For given values of the reflection coefficient σ, and diffusive permeability Ps, measured independently for a membrane of unknown heteroporosity, how accurately can the rejection coefficient R be predicted by using the Spiegler—Kedem expression for rejection, derived without concern for heteroporosity? For the case of applied pressure much greater than back-osmotic pressure, limits are analytically derived which show a maximum 30% relative error in R at σ → 0, and a maximum absolute error of 0.06 at σ ? 0.5. Experimental regions where heteroporosity effects should be largest are given explicitly. It appears that, except for these regions, the Spiegler—Kedem equation can be used to describe accurately rejection across membranes of arbitrary heteroporosity. p]For the case of appreciable solute concentration in the feedstream, a proposed test of heteroporosity consists of measurements of rejection vs. volume flux, at small and large solute concentrations. For a particular model of membrane structure called the two-pipe model it is shown that, in principle, heteroporosity can result in significant changes of rejection with concentration at a given volume flow, but for three real membranes used as examples the effects are predicted to be relatively small. 相似文献
56.
Maul J Strachnov I Eberhardt K Karpuk S Passler G Trautmann N Wendt K Huber G 《Analytical and bioanalytical chemistry》2006,386(1):109-118
A combined setup for spatially resolved mass analysis of trace amounts of elements and macromolecules is presented. Using
a MALDI-TOF mass spectrometer, a laser spectroscopic setup for resonant ionization of neutral atoms has been implemented.
This allows for an efficient and selective detection of trace elements by means of resonance ionization mass spectrometry
(RIMS). The instrumental scheme is described, and methodological developments are presented. In a first application pure,
laser desorption/ionization with TOF-MS was used to measure mass distributions of cosmic nanodiamonds. For further applications
regarding the spatially resolved ultra-trace analysis of elements in solid samples, an implanted target was used to characterize
both laser desorption/ionization and laser desorption/resonance ionization for the detection of trace elements within. A perspective
of the setup is given and future investigations are outlined. 相似文献
57.
A. Teigelh?fer P. Bricault O. Chachkova M. Gillner J. Lassen J. P. Lavoie R. Li J. Mei?ner W. Neu K. D. A. Wendt 《Hyperfine Interactions》2010,196(1-3):161-168
Due to the large absorption cross section for optical transitions into Rydberg and autoionizing states compared to non-resonant ionization, these states are of particular interest for use in efficient laser resonance ionization excitation schemes as used in Resonant Ionization Laser Ion Sources (RILIS). In order to identify these atomic states extensive laser spectroscopy has to be performed. The lasers employed at TRIUMF’s laser ion source are birefringent filter tuned titanium:sapphire (Ti:Sa) lasers which are designed for long term frequency stability rather than continuous tuning. The design and characteristics of a grating tuned, high repetition rate, pulsed Ti:Sa laser for spectroscopy applications are presented. This laser allows fast scans of up to 40 THz with a laser linewidth of approximately 6 GHz. First tests were performed by scanning across the Rydberg series of gallium. 相似文献
58.
Hyland B Svensson CE Ball GC Leslie JR Achtzehn T Albers D Andreoiu C Bricault P Churchman R Cross D Dombsky M Finlay P Garrett PE Geppert C Grinyer GF Hackman G Hanemaayer V Lassen J Lavoie JP Melconian D Morton AC Pearson CJ Pearson MR Phillips AA Schumaker MA Smith MB Towner IS Valiente-Dobón JJ Wendt K Zganjar EF 《Physical review letters》2006,97(10):102501
A high-precision branching ratio measurement for the superallowed beta+ decay of 62Ga was performed at the Isotope Separator and Accelerator radioactive ion beam facility. Nineteen gamma rays emitted following beta+ decay of 62Ga were identified, establishing the dominant superallowed branching ratio to be (99.861+/-0.011)%. Combined with recent half-life and Q-value measurements, this branching ratio yields a superallowed ft value of 3075.6+/-1.4 s for 62Ga decay. These results demonstrate the feasibility of high-precision superallowed branching ratio measurements in the A>or=62 mass region and provide the first stringent tests of the large isospin-symmetry-breaking effects predicted for these decays. 相似文献
59.
Tone Takahashi Hideki Tomita Motoi Nakayama Yoshitaka Adachi Volker Sonnenschein Tetsuo Iguchi Klaus Wendt 《Hyperfine Interactions》2013,218(1-3):133-138
2D coordination polymer iron(II) spin crossover complexes containing 3,5-lutidine with host framework Fe(3,5-lutidine)2Ni(CN)4were synthesized. Their spin crossover properties were studied by temperature dependent 57Fe Mössbauer spectroscopy. Materials show gradual incomplete spin crossover with distinct thermochromism, while only 25 % of iron(II) ions are switched to the low spin state at 80 K, as determined by a detailed 57Fe Mössbauer study. 相似文献
60.
Takaaki Takatsuka Hideki Tomita Tetsu Sonoda Volker Sonnenschein Chika Sakamoto Hiroki Mita Takuma Noto Chikara Ito Shigetaka Maeda Tetsuo Iguchi Michiharu Wada Klaus Wendt Iain Moore 《Hyperfine Interactions》2013,216(1-3):41-46
93Nb(n, n′)93mNb reaction allows retrospective estimation of integrated fast neutron dose in nuclear reactor. We proposed isomer-selective trace analysis of 93mNb by Resonance Ionization Mass Spectrometry (RIMS) combined with a gas-jet atomic source and an injection locked Ti:Sapphire laser system operated at several kHz. Resonant ionization spectroscopy of Nb in gas-jet using Ti:Sapphire laser was demonstrated. 相似文献