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71.
基于文献[5]中我们所获得的本征型光学双稳系统的熵产生表达式,本文证明该系统(光学被动腔)能够很好地满足最小熵产生定理。
关键词: 相似文献
72.
Mohamed G. G. Nour El-Dien F. A. El-Gamel N. E. A. 《Journal of Thermal Analysis and Calorimetry》2002,67(1):135-146
The present work aims chiefly to study the thermal behaviour of complex compounds with general formula: [M(HL)xH2O](A)yH2O (where HL=C13H11N4O2=6-(2-pyridylazo)-3-acetamidophenol (PAAP), M=Cu(II), Zn(II), Cd(II) and Fe(III) x=1, 3; y=2, 5) while A=CH3COO– (Ac), Cl2. The second formula is [M(H2L)xH2O]Cl2yH2O, (where H
2
L=C13H12N4O2 (PAAP), M=Ni(II), Co(II) x=3; y=4, 6). The compounds were identified by elemental analysis, FT-IR spectra and TG/DTG,DTA methods. It was found that during the thermal decomposition of complex compounds water molecules of crystallization are released in the first step. In the next step the pyrolysis of organic ligand takes place. Metal oxide remained as a solid product of the thermal decomposition. Mass spectroscopy has been used for the determination of the thermal decomposition on the intermediate products. It was found that the thermal stability of the studied compounds increases as the ionic radii decreases. The activation energy E, the entropy change S
*, the enthalpy H
* change and Gibbs free energy change G
* were calculated from TG curve.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
73.
The present work aims chiefly to study the thermal behaviour of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with 6-(2-pyridylazo)-3-acetamidophenol (PAAP) in nitrogen atmosphere. The moieties of the prepared complexes contain mainly coordinated water molecules (1-3) together with some water of crystallization. The water molecules of crystallization are removed in a single stage. The decomposition and combustion of the fragments occur in the second and subsequent stages. The fragmentation of the prepared complexes is also studied by mass spectrometry in order to identify the molecular ions obtained. The comparison of thermal analysis (TG) and mass spectra of the compounds is helpful in checking the correct proposed thermal decomposition schemes. This comparative study shows that mass spectra are correlated with the thermal analyses suggestions. The activation thermodynamic parameters of thermal decomposition pathways, such as energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the stability of the thermal treated complexes is discussed, which shows that the thermal stabilities of the complexes are enhanced as the ionic radii decrease. 相似文献
74.
Malika Berredjem Zine Regainia Georges Dewynter Jean Louis Montero Nour‐Eddine Aouf 《Heteroatom Chemistry》2006,17(1):61-65
A series of new chiral N,N′‐sulfonyl bis‐oxazolidin‐2‐ones were synthesized starting from 2‐aminoalcohols, sulfuryl chloride, and diethyl carbonate. This method utilizes natural amino acids as a source of chirality for the preparation of oxazolidinones. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:61–65, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20183 相似文献
75.
76.
77.
This paper describes the development of screen-printed (SPE) and carbon paste (CPE) sensors for the rapid and sensitive quantification of naphazoline hydrochloride (NPZ) in pharmaceutical formulations. This work compares the electroactivity of conventional carbon paste and screen-printed carbon paste electrodes towards potentiometric titration of NPZ. The repeatability and accuracy of measurements performed in the analysis of these pharmaceutical matrices using new screen printed sensors were evaluated. The influence of the electrode composition, conditioning time of the electrode and pH of the test solution, on the electrode performance were investigated. The drug electrode showed Nernstain responses in the concentration range from 1 × 10(-6) to 1 × 10(-2) mol L(-1) with slopes of 57.5 ± 1.3 and 55.9 ± 1.6 mV per decade for SPE and CPE, respectively, and was found to be very precise and usable within the pH range 3-8. These sensors exhibited a fast response time (about 3 s for both SPE and CPE, respectively), a low detection limit (3.5 × 10(-6) and 1.5 × 10(-6) M for SPE and CPE, respectively), a long lifetime (3 and 2 months for SPE and CPE, respectively) and good stability. The selectivity of the electrode toward a large number of inorganic cations, sugars and amino acids was tested. It was applied to potentiometric determination of NPZ in pure state and pharmaceutical preparation under batch conditions. The percentage recovery values for the assay of NPZ in tablets (relative standard deviations ≤0.3% for n = 4) were compared well with those obtained by the official method. 相似文献
78.
Hanan F. Abd El-Halim F. A. Nour El-Dien Gehad G. Mohamed Nehad A. Mohamed 《Journal of Thermal Analysis and Calorimetry》2013,111(1):173-181
New seven metal complexes of tioconazole drug with the general formulae [MCl2(L)2(H2O)x].yH2O (where, x = 0 and y = 1 for M = Mn(II) or x = 2, y = 2 for M = Co(II)), and x = 0, y = 3 for M = Cu(II), Ni(II), Zn(II)) and [MCl2(L)2(H2O)2]Cl.3H2O (where M = Cr(III) and Fe(III)) have been prepared and characterized based on elemental analyses, IR, magnetic moment, molar conductance, and thermal analyses techniques. From molar conductance data bivalent metal chelates are non-electrolytes while Cr(III) and Fe(III) chelates are electrolytes and of 1:1 type. According to the IR spectral data, TCNZ is coordinated to the metal ions in a neutral unidentate manner with N donor site of the imidazole–N. All the complexes are octahedral except Mn(II) complex has tetrahedral structure. TCNZ drug and its metal complexes were also screened for their biological activity. 相似文献
79.
卟啉纳米材料制备及在可视化传感器中的应用 总被引:1,自引:0,他引:1
在水/油体系中,利用表面活性剂辅助自组装制备出5,10,15,20-四苯基卟啉锌(ZnTPP)和5,10,15,20-四苯基卟啉钴(CoTPP)纳米材料,改变陈化时间制备多种形貌卟啉纳米材料,如纳米球、纳米棒和纳米片等。利用紫外-可见光谱和荧光光谱分析两种卟啉纳米材料的光学性质,ZnTPP纳米材料的荧光强度是其单体的4.5倍,具有良好光敏性。基于两种卟啉纳米材料构建可视化阵列芯片对挥发性气体己醛检测,卟啉纳米的响应度是它们单体的2倍。 相似文献
80.
Nijem N Kong L Zhao Y Wu H Li J Langreth DC Chabal YJ 《Journal of the American Chemical Society》2011,133(13):4782-4784
The role of low binding energy sites on the adsorption of H(2) in metal-organic frameworks (MOFs) with unsaturated metal centers has not been identified. For instance, the importance of the benzene sites on H(2) adsorption at the metal site in MOF-74 has not been established. We report here experimental evidence that unambiguously shows that the internal mode of H(2) adsorbed at the metal site undergoes both a frequency shift and a marked change in its dynamic dipole moment when H(2) is adsorbed at the next nearest neighbor "benzene" site in MOF-74-Co. The effect of loading (i.e., occupation of all benzene sites) also induces spectroscopic shifts in H(2) at the metal site. These interactions highlight the role of lower binding energy sites in H(2) adsorption. 相似文献