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21.
Kakaba Madi Peter Nyabeze Oswald Gwavava Matome Sekiba Baojin Zhao 《Journal of Radioanalytical and Nuclear Chemistry》2014,301(2):351-363
Gamma ray measurements were carried out along two parallel lines close to each of the hot springs using a RS 125 spectrometer to find the concentration (ppm) of U, Th, and K at Polile Tshisa, Aliwal North, and Badfontein hot springs. The RS 125 spectrometer is auto-stabilized on the naturally occurring U, Th, and K, and provides concentrations (ppm) of the radioelements. The results show that the concentration of thorium is higher, and is below the world average hazardous threshold of 7.4 ppm. Thorium is related to the occurrence of monazite seen at the scanning electron microscope. Higher ratios of U/K are indicative of an increase of uranium relative to potassium. Binary diagrams (Th–U, K–U, and K–Th) do not show a clear best fit except at Polile Tshisa hot spring where thorium shows a quasi positive correlation to potassium. In general, it can be concluded that the concentrations of these three radioelements are quite low, acceptable for groundwater, and could be hazardous to the health of humans and animals if exposed to long time radiations. 相似文献
22.
Dr. Dennis Kubiczek Heinz Raber Dr. Nicholas Bodenberger Thomas Oswald Melis Sahan Daniel Mayer Dr. Sebastian Wiese Prof. Dr. Steffen Stenger Prof. Dr. Tanja Weil Dr. Frank Rosenau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(64):14536-14545
Textbook procedures require the use of individual aptamers enriched in SELEX libraries which are subsequently chemically synthesized after their biochemical characterization. Here we show that this reduction of the available sequence space of large libraries and thus the diversity of binding molecules reduces the labelling efficiency and fidelity of selected single aptamers towards different strains of the human pathogen Pseudomonas aeruginosa compared to a polyclonal aptamer library enriched by a whole-cell-SELEX involving fluorescent aptamers. The library outperformed single aptamers in reliable and specific targeting of different clinically relevant strains, allowed to inhibit virulence associated cellular functions and identification of bound cell surface targets by aptamer based affinity purification and mass spectrometry. The stunning ease of this FluCell-SELEX and the convincing performance of the P. aeruginosa specific library may pave the way towards generally new and efficient diagnostic techniques based on polyclonal aptamer libraries not only in clinical microbiology. 相似文献
23.
Alberto Caprara Marcus Oswald Gerhard Reinelt Robert Schwarz Emiliano Traversi 《Mathematical Programming Computation》2011,3(3):261-280
We solve for the first time to proven optimality the small instances in the classical literature benchmark of Minimum Linear
Arrangement. This is achieved by formulating the problem as an ILP in a somehow unintuitive way, using variables expressing
the fact that a vertex is between two other adjacent vertices in the arrangement. Using (only) these variables appears to
be the key idea of the approach. Indeed, with these variables already the use of very simple constraints leads to good results,
which can however be improved with a more detailed study of the underlying polytope. 相似文献
24.
Jan Remsa Miroslav Jelinek Tomáš Kocourek Ji?í Oswald Marian ?erňanský Michal Jelínek 《Applied Surface Science》2009,255(10):5292-5294
High quality, thick, highly oriented crystalline thin films of Yttrium Aluminum Garnet (Y3Al5O12) and Yttrium Aluminum Perovskite (YAlO3) doped with Erbium were prepared by pulsed laser deposition. Samples were created in vacuum or oxygen environment. Depositions were arranged at room temperature, or at high substrate temperatures ranging from 800 to 1100 °C. Amorphous layers were annealed by laser, or in oven (argon flow, temperatures in range from 1200 to 1400 °C). Fused silica and sapphire (0 0 0 1) were used as substrates. Properties of films were characterized by X-ray diffraction, atomic force microscopy, and by photoluminescence measurement. Size of crystalline grains was in the range 116-773 nm. Thickness of layers was up to 17 μm. 相似文献
25.
26.
J.P. DuignanI.D.H. Oswald I.C. SageL.M. Sweeting K. TanakaT. Ishihara K. HiraoG. Bourhill 《Journal of luminescence》2002,97(2):115-126
There are many reports in the literature of a spectral difference between the triboluminescence (TL) spectrum and the solid-state photoluminescence (PL) spectrum of the same compound. Numerous reasons have been suggested for this difference including pressure-induced changes to Franck-Condon factors during the lifetime of the TL light emission; self-absorption of the TL emission and fracture-induced symmetry changes perturbing the local field of the TL emitting species. However, in a number of cases, the luminescent spectra were recorded on different equipment with different spectral responses, with the resolution of either luminescent spectrum rarely quoted. To avoid artificial spectral differences, care must be taken to account for the response of each equipment over the wavelength range studied, as well as any resolution difference. We have therefore measured the TL and solid-state PL spectra of sixteen TL compounds on the same spectrometer at an identical resolution. Furthermore, the solid-state photoluminescent lifetime has been determined for all samples and the implication that these values have for observing pressure-induced (Franck-Condon) luminescent spectral changes discussed. Finally, in all cases where a significant difference was observed between TL and PL spectra, either self-absorption of the TL emission or fracture-induced perturbations of the local field have been evoked to explain the difference. 相似文献
27.
28.
Baudry J Pirkl S Oswald P 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,60(3):2990-2993
We show that the drift velocity of the cholesteric fingers of the second species in ac electric field strongly depends on the conductivity of the liquid crystal chosen and exponentially vanishes above a cutoff frequency we found to be equal (within a numerical factor close to 1) to the charge relaxation frequency of the sample. We further show that the drift velocity is proportional to the applied electric field, provided that the confinement ratio is kept constant. 相似文献
29.
The fluorescence characteristics of selected hallucinogenic drugs dissolved in solutions of α-cyclodextrin and β-cyclodextrin are reported. Fluorescence intensity enhancements in cyclodextrin media relative to aqueous solution range from 1.2 to 4.0, probably because inclusion of the drugs into cyclodextrin increases the quantum yield. Calibration graphs are linear over 2–3 orders of magnitude; limits of detection are 6–13 μg l?1 for ibogaine and N,N-dimethyltryptamine. The mescaline derivatives show limits of detection in the 0.8–1.4 ppm range. The role of cyclodextrin in enhancing the fluorescence intensities and some of the criteria for this fluorescence enhancement are discussed. 相似文献
30.
Oswald Leroy 《Proceedings Mathematical Sciences》1971,73(5):232-239
In the problem of the diffraction of light by two parallel supersonic waves, consisting of a fundamental tone and itsn-th harmonic, the solution of the system of difference-differential equations for the amplitudes has been reduced to the integration of a partial differential equation. The expressions for the amplitudes of the diffracted light waves are obtained as the coefficients of the Laurent expansion of the solution of this partial differential equation. The latter has been integrated for two approximations:
- Forρ = 0, the results of Murty’s elementary theory are reestablished.
- Forρ ≤ 1, a power series inρ, the terms of which are calculated as far as the third one, leads to a new expression for the intensities of the diffracted light waves, verifying the general symmetry properties obtained by Mertens.