排序方式: 共有33条查询结果,搜索用时 375 毫秒
31.
Carolina V. Barra Fillipe V. Rocha Adelino V. G. Netto Regina C. G. Frem Antonio E. Mauro Iracilda Z. Carlos Sandra R. Ananias Marcela B. Quilles 《Journal of Thermal Analysis and Calorimetry》2011,106(2):489-494
This study describes the synthesis, IR, 1H, and 13C{1H} NMR spectroscopic as well the thermal characterization of the new palladium(II) pyrazolyl complexes [PdCl2(HmPz)2] 1, [PdBr2(HmPz)2] 2, [PdI2(HmPz)2] 3, [Pd(SCN)2(HmPz)2] 4 {HmPz = 4-methylpyrazole}. The residues of the thermal decomposition were identified as Pd0 by X-ray powder diffraction. From the initial decomposition temperatures, the thermal stability of the complexes can be ordered
in the sequence: 1 > 2 > 4 ≈ 3. The cytotoxic activities of the complexes and the ligand were investigated against two murine cancer cell lines: mammary
adenocarcinoma (LM3) and lung adenocarcinoma (LP07) and compared to cisplatin under the same experimental conditions. 相似文献
32.
Ananias D Ferreira A Rocha J Ferreira P Rainho JP Morais C Carlos LD 《Journal of the American Chemical Society》2001,123(24):5735-5742
The synthesis and structural characterization of the first examples of microporous europium(III) and terbium(III) silicates (Na(4)K(2)X(2)Si(16)O(38) x 10H(2)O, X = Eu, Tb) are reported. The structure of these solids was solved by powder X-ray diffraction ab initio (direct) methods and further characterized by chemical analysis (EDS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), (23)Na and (29)Si magic-angle spinning (MAS) NMR, and luminescence spectroscopy. Both materials display interesting photoluminescence properties and present potential for applications in optoelectronics. This work illustrates the possibility of combining in a given silicate microporosity and optical activity. 相似文献
33.
E.M.C. Abreu J. Ananias Neto A.C.R. Mendes C. Neves W. Oliveira 《Annalen der Physik》2012,524(8):434-455
The concept of gauge invariance is one of the most subtle and useful concepts in modern theoretical physics. It is one of the Standard Model cornerstones. The main benefit due to the gauge invariance is that it can permit the comprehension of difficult systems in physics with an arbitrary choice of a reference frame at every instant of time. It is the objective of this work to show a path of obtaining gauge invariant theories from non‐invariant ones. Both are named also as first‐ and second‐class theories respectively, obeying Dirac's formalism. Namely, it is very important to understand why it is always desirable to have a bridge between gauge invariant and non‐invariant theories. Once established, this kind of mapping between first‐class (gauge invariant) and second‐class systems, in Dirac's formalism can be considered as a sort of equivalence. This work describe this kind of equivalence obtaining a gauge invariant theory starting with a non‐invariant one using the symplectic embedding formalism developed by some of us some years back. To illustrate the procedure it was analyzed both Abelian and non‐Abelian theories. It was demonstrated that this method is more convenient than others. For example, it was shown exactly that this embedding method used here does not require any special modification to handle with non‐Abelian systems. 相似文献