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A. Taghavi V. Darvish H. M. Nazari S. S. Dragomir 《Annali dell'Universita di Ferrara》2017,63(2):377-389
In this paper, we prove some singular value inequalities for sum and product of operators. Also, we obtain several generalizations of recent inequalities. Moreover, as applications we establish some unitarily invariant norm and trace inequalities for operators which provide refinements of previous results. 相似文献
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Mousa Ghaemy Samaneh Sharifi Seyed Mojtaba Amini Nasab Mehdi Taghavi 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5):487-497
Two new symmetrical diamines were designed and synthesized having different functional groups such as a pair of phenyl ether linkages, 2,3-diaryl substituted imidazole rings and CF3 groups as pendant, and characterized by FT-IR, 1H and 13C-NMR spectroscopy and elemental analysis. A series of new fluorescent poly(imide-ether)s (PIEs) was prepared by polymerization of the diamines with commercial tetracarboxylic dianhydrides such as pyromellitic dianhydride and 3,3′,4,4′-benzophenone tetracarboxylic dianhydride. The resulting PIEs were amorphous and had intrinsic viscosity [η] in the range of 0.42–0.51 dL/g. The weight average molecular weights (Mw) of these polymers were measured by GPC and were in the range of 28658–35595 g/mol with molecular weight distribution (MWD) of 2.12–2.27. These polymers were readily soluble in a variety of organic solvents and formed low-colored and flexible thin films with cut-off wavelength (λ0) in the range of 385–420 nm, and all PIEs films exhibited high optical transparency. They also possessed good thermal stability with 10% weight loss temperatures (T10%) in the range 486–537°C in N2. The glass transition temperatures (Tg) of PIEs are in the range 251–324°C. These polymers showed fluorescence emission in film and in solution at 459–476 nm with the quantum yields in the range 4–12%. 相似文献
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Mohammad Abbasi Mohammad Reza Mohammadizadeh Zeinab Khatoon Taghavi 《Journal of the Iranian Chemical Society》2013,10(2):201-205
An efficient and odorless synthesis of disulfides from alkyl halides using thiourea and elemental sulfur in the presence of sodium carbonate in wet polyethylene glycol (PEG 200) at 40 °C without contamination by higher polysulfides has been developed. This procedure was then extended to preparation of disulfides from alkyl tosylates at 70 °C. 相似文献
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M. Giahi A. Moradidoost M. A. Bagherinia H. Taghavi 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(13):2279-2284
The photocatalytic degradation of cetyl pyridinium chloride (CPC) has been investigated in aqueous phase using ultraviolet (UV) and ZnO nanopowder. Kinetic analysis showed that the extent of surfactant photocatalytic degradation can be fitted with pseudo-first-order model and photochemical elimination of CPC could be studied by Taguchi method. Our experimental design was based on testing five factors, i.e., dosage of K2S2O8, concentration of CPC, amount of ZnO, irradiation time and initial pH. Each factor was tested at four levels. The optimum parameters were found to be pH 5.0; amount of ZnO 11 mg; K2S2O8 3 mM; CPC 10 mg/L; irradiation time, 8 h. 相似文献
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Three diamine monomers with different derivatives of imidazole heterocyclic ring and meta-linked aryl ethers were synthesized and used in polycodensation reaction with various commercial dianhydrides for preparation of a series of novel poly(ether-imide) (PEI)s. The polycodensation reactions were carried out by using conventional method and in a green medium of ionic liquid (IL) without using NMP-pyridine-acetic anhydride. The PEIs were obtained in good yields (80% 96%) with moderate viscosity (0.48 0.66 dL/g) in a shorter reaction time (10 h) in IL as compared with the conventional method (36 h). All of the polymers were amorphous in nature, showed excellent solubility in amide-type polar aprotic solvents with ability to form tough and flexible films, and excellent thermal stability with Tgs in the range of 212 340 ℃ and 10% weight loss temperature (T10) up to 570℃ in N 2 and 528 ℃ in air. 相似文献
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Mahsa Taghavi Sirous Ebrahimi Jafarsadegh Moghaddas 《Journal of Dispersion Science and Technology》2014,35(8):1097-1105
The recently developed centrifugal impeller is examined to investigate the solid–liquid mixing in a mechanically agitated contactor. Using the sample withdrawal method, the effects of impeller geometrical parameters, impeller rotational speed (200–700 rpm), solid particle size (500–1100 µm), and solid loading (2–10 vol%) on the degree of homogeneity are studied. The axial and the radial solid concentration profiles and the minimum impeller speed for the complete homogenization are also determined. In comparison with a widely used propeller impeller, considerably higher homogeneity values in lower impeller speeds are obtained (90% homogeneity against 16% homogeneity at 200 rpm at the same conditions). Having also lower power consumption makes this a superior impeller in solid–liquid mixing processes especially in shear-sensitive systems. 相似文献
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