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991.
A multi-element analytical method based on inductively coupled plasma atomic emission spectrometry (ICP-AES) was developed
for trace elements in pharmaceutical tablets and cosmetics. Titanium was also included in the analytes since it is widely
used in pharmaceuticals. Critical ICP conditions, like RF incident power, argon gas flow rate and nebulizer sample uptake
flow rate were optimized. The most sensitive spectral line of each analyte was selected as optimum for further study. Detection
limits in the low μg g−1 range were obtained. Prior to chemical analysis, the samples were decomposed by acid digestion, using various mixtures of
HCl, HNO3 and HF. Yttrium was used as a suitable internal standard in order to correct for possible matrix effects. The method was
applied to the analysis of six different pharmaceutical products (anti-biotic, anti-inflammatory, anti-hypertensive) in the
form of tablets with film coating and also three cosmetic products like hair and face masks. 相似文献
992.
993.
This paper proposes to obtain homogeneous and stable blends of oligo(9,9-dioctylfluorene)-co-phenylene (OF), a conjugated oligomer with strong tendency of formation of excimers in the solid state, and nitrile rubber (NBR). This rubber protection reduces the formation of polymer excimers in the films. The fluorene oligomer was synthesized via Suzuki reaction and incorporated in the nitrile rubber. The films were formed by spin coating and casting techniques on the proportions of 1, 5, 10, 20 and 50 % (w/w) of OF in the nitrile rubber (NBR). The structural, optical and thermal properties of the films were evaluated with infrared, UV–Vis, fluorescence and thermogravimetry, respectively. The nitrile rubber proved to be essential for the preparation of homogeneous and stable films, since it was not possible to obtain films with only fluorene using the above-mentioned techniques. Furthermore, luminescent properties of OF are unchanged and the excimers formation in the solid state decrease suggesting the efficiency of nitrile rubber as the matrix for making films. 相似文献
994.
The inclusion complexes of a series of 4-arylidenamino-5-phenyl-4H-1, 2, 4-triazole-3-thiols have been prepared with β-cyclodextrin. The compounds and their inclusion complexes have been characterized by studying their physical and spectral properties. The thermodynamic stability constant and free energy of activation have been determined to know the stability of inclusion complexes and type of host-guest relation. Finally, absorption, excitation and emission spectra of the compounds (4-arylidenamino-5-phenyl-4H-1, 2, 4-triazole-3-thiols) and their inclusion complexes have been taken. It is found that inclusion complex formation brings about a drastic change in absorption and fluorescence characteristic (both excitation and emission spectra) of newly synthesized compounds. 相似文献
995.
Identification,characterization and evolution of non-local quasi-Lagrangian structures in turbulence
Yue Yang 《Acta Mechanica Sinica》2016,32(3):351-361
The recent progress on non-local Lagrangian and quasi-Lagrangian structures in turbulence is reviewed. The quasi-Lagrangian structures, e.g., vortex surfaces in vis-cous flow, gas-liquid interfaces in multi-phase flow, and flame fronts in premixed combustion, can show essential Lagrangian following properties, but they are able to have topological changes in the temporal evolution. In addition, they can represent or influence the turbulent flow field. The challenges for the investigation of the non-local structures include their identification, characterization, and evolution. The improving understanding of the quasi-Lagrangian struc-tures is expected to be helpful to elucidate crucial dynamics and develop structure-based predictive models in turbulence. 相似文献
996.
Chu Rainer Kwang-Hua 《Journal of Experimental and Theoretical Physics》2016,123(5):822-826
We illustrate the possible acceleration of cosmic rays passing through a kind of amplification channel (via diffusion modes of propagating plane-wave fronts) induced by a rotating system. Our analysis is mainly based on the quantum discrete kinetic model (considering a discrete Uehling-Uhlenbeck collision term), which has been used to study the propagation of plane (e.g., acoustic) waves in a system of rotating gases. 相似文献
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