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51.
Some properties of the second homology and cover of Leibniz algebras are established. By constructing a stem cover, the second Leibniz homology and cover of abelian, Heisenberg Lie algebras and cyclic Leibniz algebras are described. Also, for the dimension of a non-cyclic nilpotent Leibniz algebra L, we obtain dim(HL2(L))≥2. 相似文献
52.
Javad Salehi Hojat Veisi Mohammad M. Khodaei Ahmad R. Khosropour 《Journal of heterocyclic chemistry》2011,48(2):484-488
Molten tetra‐n‐butylphosphonium bromide is found to be a practical and inexpensive catalytic media for stereoselective one‐pot synthesis of pyranoquinoline and furanoquinoline derivatives in good to excellent yields. Products of undesirable reactions resulting from polymerization are not observed. The use of this catalyst media avoids the use of any cocatalysts or toxic organic solvents. J. Heterocyclic Chem., (2011). 相似文献
53.
Reza Ojani Jahan-Bakhsh Raoof Banafsheh Norouzi 《Journal of Solid State Electrochemistry》2011,15(6):1139-1147
Poly(isonicotinic acid) (PINA) film was electrosynthesized on carbon paste electrode (CPE) by using the repeated potential
cycling technique in aqueous solution containing isonicotinic acid (INA), sulfuric acid and sodium dodecyl sulfate (SDS).
Then, nickel and cobalt ions were incorporated by immersion of CPE/PINA prepared in the presence of SDS (CPE/PINA(SDS)) in
a solution with different proportions of nickel chloride and cobalt chloride. The electrochemical characterization of mixed
hydroxides containing cobalt and nickel at the surface of the modified electrode is presented. The modified electrodes were
successfully used in the electrocatalytic oxidation of glucose. Finally, the electrocatalytic oxidation peak currents of glucose
exhibited a good linear dependence on concentration, and its quantification can be done easily. The good analytical performance,
low cost and straightforward preparation method make this novel electrode material promising for the development of an effective
glucose sensor. 相似文献
54.
In this paper, a semi-classical formulation for modeling photonic-crystal (PC) structures with a four-layer multi quantum well (MQW) active region is presented. The formulation treats the electromagnetic fields as a classical entity, while employing the quantum-mechanically derived rate equations to analyze the active medium. Using the Poynting theorem, we interrelate the two sets of equations, namely the MQW rate equations and Maxwell's equations. The formulation involves the stimulately emitted photon density in the former and a virtual volume current density representing the generated photons in the latter. With the help of this formulation, we then model a PC optical amplifier as well as a PC hexagonal-defect cavity laser and solve the obtained equations after replacing the involved spatial and temporal derivatives by pseudo-spectral and Runge-Kutta's formulations, respectively. The formulation also takes the effect related to gain saturation and frequency broadening into account. 相似文献
55.
Novel 1,4-dihydropyridines (1,4-DHPs) are prepared efficiently via Hantzsch reaction using aldehydes, benzylacetoacetate and catalytic amount of iron(III) phosphate under solvent-free conditions in good yields. 相似文献
56.
An efficient synthetic method for the synthesis of a basic amine dendron grafted on SBA-15 and a related Pd(II) complex as two novel catalysts has been developed. The prepared catalysts were evaluated in Henry and Suzuki–Miyaura coupling reactions and were found to exhibit excellent heterogeneous catalytic activity in green media, and could be easily separated and reused several times. 相似文献
57.
Ahmad Khoramabadi-Zad Safar-Ali Akbari Azam Shiri Hojat Veisi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2443-2449
Abstract Preparation methods of dibenzoxanthene derivatives are surveyed alongside the synthesis of some of the titled compounds, which are the sulfur analogues of dibenzoxanthenes. Our new procedure for the conversion of phenols to thiophenols was used to prove the structure of such sulfur analogues. 相似文献
58.
Banafsheh Vahdani Alviri Mehrdad Pourayoubi Abdul Ajees Abdul Salam Marek Ne
as Arie van der Lee Akshara Chithran Krishnan Damodaran 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(1):104-116
The crystal structures of diphenyl (cycloheptylamido)phosphate, C19H24NO3P or (C6H5O)2P(O)(NHC7H13), ( I ), and diphenyl (dibenzylamido)phosphate, C26H24NO3P or (C6H5O)2P(O)[N(CH2C6H5)2], ( II ), are reported. The NHC7H13 group in ( I ) provides two significant hydrogen‐donor sites in N—H…O and C—H…O hydrogen bonds, needed for a one‐dimensional hydrogen‐bond pattern along [100] in the crystal, while ( II ), with a (C6H5CH2)2N moiety, lacks these hydrogen bonds, but its three‐dimensional supramolecular structure is mediated by C—H…π interactions. The conformational behaviour of the phenyl rings in ( I ), ( II ) and analogous structures from the Cambridge Structural Database (CSD) were studied in terms of flexibility, volume of the other group attached to phosphorus and packing forces. From this study, synclinal (±sc), anticlinal (±ac) and antiperiplanar (±ap) conformations were found to occur. In the structure of ( II ), there is an intramolecular Cortho—H…O interaction that imposes a +sc conformation for the phenyl ring involved. For the structures from the CSD, the +sc and ±ap conformations appear to be mainly imposed by similar Cortho—H…O intramolecular interactions. The large contribution of the C…H/H…C contacts (32.3%) in the two‐dimensional fingerprint plots of ( II ) is a result of the C—H…π interactions. The differential scanning calorimetry (DSC) analyses exhibit peak temperatures (Tm) at 109 and 81 °C for ( I ) and ( II ), respectively, which agree with the strengths of the intermolecular contacts and the melting points. 相似文献
59.
The electrocatalytic oxidation of hydrazine at a carbon paste electrode spiked with acetylferrocene as a mediator was studied by cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. In contrast to other ferrocenic compounds, acetylferrocene exhibits a chemical irreversible behavior, but it can act as an effective mediator for electrocatalytic oxidation of hydrazine, too. The heterogeneous electron transfer rate constant between acetylferrocene and the electrode substrate (carbon paste) and the diffusion coefficient of spiked acetylferrocene in silicon oil were estimated to be about 3.45×10?4 cm s?1 and 4.45×10?9 cm2 s?1, respectively. It has been found that under the optimum conditions (pH 7.5) the oxidation of hydrazine occurs at a potential of about 228 mV less positive than that of an unmodified carbon paste electrode. The catalytic oxidation peak current of hydrazine was linearly dependent on its concentration and the obtained linear range was 3.09×10?5 M–1.03×10?3 M. The detection limit (2σ) has been determined as 2.7×10?5 M by cyclic voltammetry. Also, the peak current was increased linearly with the concentration of hydrazine in the range of 1×10?5 M–1×10?3 M by differential pulse voltammetry with a detection limit of 1×10?5 M. This catalytic oxidation of hydrazine has been applied as a selective, simple, and precise new method for the determination of hydrazine in water samples. 相似文献
60.
N,N,N′,N′-Tetrabromobenzene-1,3-disulfonamide and poly(N,N′-dibromo-N-ethylene-benzene-1,3-disulfonamide) in concentrated H2SO4 can be used as efficient reagents for the mild bromination of unreactive arenes at room temperature, under solvent-free conditions, in good yields. 相似文献