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991.
Mennickent Sigrid Mario Vega M. Mario Vega H. De Diego Marta Fierro Ricardo 《平面色谱法杂志一现代薄层色谱法》2012,25(1):54-59
JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatography (HPTLC) method for the quantification of propranolol in human serum is developed and... 相似文献
992.
Pena Ruiz Tomas Drzewiecka Aleksandra Koziol Anna E. Fernandez Gomez Manuel Ostrowska Kinga Struga Marta Kossakowski Jerzy 《Structural chemistry》2012,23(5):1573-1584
Structural Chemistry - The structural analysis of khellinone and visnaginone indicated the planarity of the benzo[b]furan ring system. The oxygen or carbon atoms of the substituents, –OH,... 相似文献
993.
994.
Tamás Szücs Daniel Bemmerer Thomas Cowan Detlev Degering Zoltán Elekes Zsolt Fül?p Gy?rgy Gyürky Arnd Junghans Matthias K?hler Michele Marta Ronald Schwengner Andreas Wagner Kai Zuber 《The European Physical Journal A - Hadrons and Nuclei》2012,48(1):1-8
In order to reliably estimate the rate of a charged particle induced nuclear reaction in a non-explosive astrophysical scenario, its cross-section must be measured far below the Coulomb barrier. However, at the corresponding energies the cross-section values are very low, so that the experimental counting rate is dominated by cosmic-ray induced background, even if a suitable anticoincidence shield is applied. This problem can be overcome by performing an accelerator-based experiment in a deep underground site, as has been done with great success at the LUNA 0.4MV accelerator in Gran Sasso, Italy. Several underground accelerators with higher beam energy are in the planning phase worldwide. All of them are shielded by over 1000m of rock, a depth at which cosmic-ray effects are negligible for the purposes of nuclear astrophysics experiments. It is shown here that a combined approach, using a shallow-underground laboratory below 47m of rock and an active shield to veto surviving muons in simple detectors, results in a background level that is not far from that of deep underground sites. Data have been obtained using two ??traveling?? ??-detectors. They have been transported both shallow underground, to the Dresden Felsenkeller in Germany, and deep underground, to the Gran Sasso laboratory in Italy. As shallow-underground facilities are more easily accessible than deep-underground ones, the present finding holds the promise of greatly accelerated progress in the field of cross-section measurements for nuclear astrophysics. 相似文献
995.
Marta Letizia Antonelli Camillo La Mesa Rosalia Fortunata Tornelli Caterina Letizia 《Thermochimica Acta》2007,456(1):13-18
Negatively charged vesicles made of non-stoichiometric amounts of sodium dodecylsulfate and cetyltrimethylammonium bromide were characterised by physico-chemical methods. Interactions with lysozyme were examined by calorimetry. A remarkable heat effect is observed upon diluting the protein with the vesicular pseudo-solvent. The maximum ΔHbind value occurs at complete vesicle charge neutralisation by the protein. 相似文献
996.
997.
The paper reports a new, nonconventional method for the preparation of oxygen-containing niobium compounds, based upon coprecipitation. The coprecipitation product of niobic acid with lead oxalate was used as precursor. Lead metaniobate was obtained by proper thermal treatment of the coprecipitate. The coprecipitate mechanism was studied and the optimal conditions for quantitative precipitation of niobium and lead were established. The mechanism of thermal decomposition of the coprecipitate was investigated by differential thermal analysis and X-ray powder diagrams. The final product of thermal decomposition, lead metaniobate, is formed at 850°C. 相似文献
998.
Marta B Ferraro Viviana Repetto Julio C Facelli 《Solid state nuclear magnetic resonance》1998,10(4):185-189
This paper presents results from applying different point charge models to take into account intermolecular interactions to model the solid state effects on the 15N NMR chemical shifts tensors. The DFT approach with the BLYP gradient corrected exchange correlation functional has been used because it can include electron correlation effects at a reasonable cost and is able to reproduce 15N NMR chemical shifts with reasonable accuracy. The results obtained with the point charge models are compared with the experimental data and with results obtained using the cluster model, which includes explicitly neighboring molecular fragments. The results show that the point charge models can take into account solid state effects at a cost much lower than the cluster methods. 相似文献
999.
Vlastimil Matejec Miloš Hayer Peter Pavlovič Marta Kubečková Gabriela Kuncová Massimo Guglielmi 《Journal of Sol-Gel Science and Technology》1995,5(3):193-199
SiO2, TiO2, ZrO2, and TiO2-ZrO2 thin coatings were applied by sol-gel method on quartz fibres during the fibre drawing. Durable layers with the thicknesses up to 0.7 m were obtained. The layer smoothness and thickness were determined using electron microprobe analyzer and electron or optical microscopy. In order to investigate a decrease in the strength of sol-gel coated fibres a novel method employing silica capillaries was developed. The fibre strength decrease was explained by the influence of water penetrating as a result of the coating process into the flaws on the fibre surface. 相似文献
1000.
An ion-pair liquid chromatographic assay was developed and validated for the determination of ceftriaxone in cerebrospinal fluid. Chromatographic separation was achieved on a C18 column (125 x 4 mm, 5 microm) with detection at 270 nm, a 1 mL/min flow rate and a 50 microL loop. The mobile phase consisted of 300 mL acetonitrile, 50 mL 0.1M phosphate buffer (pH 7.4), 3.2 g tetrabutylammonium bromide as the ion-pairing agent, and dilution with distilled deionized water to 1 L. Cephradine was used as the internal standard. The assay was linear for ceftriaxone concentrations of 0.5-50 microg/mL. The coefficients of variation for precision were <4.61%. The accuracy ranged from 96.07 to 102.42%. The detection and quantitation limits were 0.019 and 0.065 microg/mL, respectively. This method was used to quantify ceftriaxone in the cerebrospinal fluid of children with meningitis. The results showed that the method described here is useful for the determination of ceftriaxone in cerebrospinal fluid. 相似文献