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排序方式: 共有180条查询结果,搜索用时 31 毫秒
81.
Nuno M.M. Moura Maria A.F. Faustino Maria G.P.M.S. Neves Augusto C. Tomé El Mostapha Rakib Abdellah Hannioui Souad Mojahidi Steffen Hackbarth Beate Röder Filipe A. Almeida Paz Artur M.S. Silva José A.S. Cavaleiro 《Tetrahedron》2012,68(39):8181-8193
2-Vinyl-5,10,15,20-tetraphenylporphyrinatozinc(II) reacts with nitrile imines, generated in situ from ethyl hydrazono-α-bromoglyoxylates, affording the corresponding pyrazolines in good to excellent yields. Treatment of pyrazoline derivatives with DDQ affords the corresponding pyrazole derivatives with moderate to excellent yields. When the hydrolysis of ester group in the pyrazoline derivatives was considered, it was observed the concomitant oxidation of the heterocyclic unit, which allowed directly obtaining porphyrin-pyrazole derivatives with a carboxylic group, in very good yields.The photophysical properties of the pyrazoline and pyrazole porphyrin derivatives show that the influence of the heterocyclic substituents is limited by the tendency of these molecules to aggregate. All other properties and especially the triplet kinetics remain unaffected. The adducts with low tendency to aggregate showed very high singlet oxygen yield, which makes these compounds interesting for their use as photosensitizers for PDT. 相似文献
82.
Samiha Dergal Samah Al-Qaisi Habib Rached Abdellah Ouerdane 《International journal of quantum chemistry》2024,124(8):e27371
The stabilities, mechanical, electronic, and magnetic properties of the new equiatomic quaternary Heusler alloy (EQHA) RuTiCrSi were investigated using the Kohn-Sham DFT (KS-DFT) calculations within the generalized gradient approach (GGA), the modified version of the exchange potential introduced by Becke and Johnson in addition to the GGA (mBJ-GGA), and Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional. The ground-state equilibrium energy reveals that the ferromagnetic with type 2 structure is the more stable. The RuTiCrSi is energetically, mechanically, and dynamically stable. The calculated self-consistent total magnetic moment is 2 μB and agrees well with the Slater-Pauling rule of . The electronic structure results from mBJ-GGA and HSE06 functionals show a half-metallic behavior. A high Curie temperature is obtained using the mean-field approximation. The thermoelectric response was calculated using the semi-classical Boltzmann transport equation under constant relaxation time. The maximum value of Seebeck coefficient is observed at the ambient temperature of . It was also observed that the power factor increases significantly as temperature rises. Therefore, the new EQHA RuTiCrSi seems to be a potential candidate for spintronic thermoelectric applications. 相似文献
83.
Cesar Auguste Badji Jean Dorland Lynda Kheloul Dimitri Brard Pascal Richomme Abdellah Kellouche Claudio Roberto Azevedo de Souza Antnio Loureno Bezerra Sylvia Anton 《Molecules (Basel, Switzerland)》2021,26(15)
Essential oils of aromatic plants represent an alternative to classical pest control with synthetic chemicals. They are especially promising for the alternative control of stored product pest insects. Here, we tested behavioral and electrophysiological responses of the stored product pest Tribolium confusum, to the essential oil of a Brazilian indigenous plant, Varronia globosa, collected in the Caatinga ecosystem. We analyzed the essential oil by GC-MS, tested the effects of the entire oil and its major components on the behavior of individual beetles in a four-way olfactometer, and investigated responses to these stimuli in electroantennogram recordings (EAG). We could identify 25 constituents in the essential oil of V. globosa, with anethole, caryophyllene and spathulenole as main components. The oil and its main component anethole had repellent effects already at low doses, whereas caryophyllene had only a repellent effect at a high dose. In addition, the essential oil abolished the attractive effect of the T. confusum aggregation pheromone. EAG recordings revealed dose-dependent responses to the individual components and increasing responses to the blend and even more to the entire oil. Our study reveals the potential of anethole and the essential oil of V. globosa in the management of stored product pests. 相似文献
84.
Abdellah Aziz El Hadj Elandaloussi Belkacem Belhalfaoui Mohand Said Ouali Louis Charles De Mnorval 《Colloids and surfaces. B, Biointerfaces》2009,73(2):192-198
Chemical functionalization of olive stone wastes with succinate linkers can potentially improve the performance of wastewater treatment technologies via enhanced adsorption and high affinity of the covalently attached succinate groups for heavy metals. In this study, a novel reusable adsorbent material based on agricultural waste has been synthesized by esterifying the lignocellulosic matrix of olive stones with succinic anhydride in toluene under basic conditions. Characterization of the as-prepared material by FTIR and solid-state MAS 13C NMR spectroscopies and TGA confirmed that the heterogeneous esterification has proceeded very efficiently to yield the succinylated-olive stone (S–OS). Subsequent alkaline treatment of S–OS with saturated NaHCO3 aqueous solution led to the resulting sodic material (NaS–OS), which was subjected to batch experiments in order to evaluate its cadmium-removing efficiency from aqueous solutions at realistic concentrations of cadmium found in industrial effluents. The results obtained from the sorption characteristics have revealed that NaS–OS material is highly effective in removing cadmium from aqueous solutions, with a maximum uptake capacity of 200 mg g−1 (1.78 mmol g−1). The Langmuir isotherm model was found to fit adequately the equilibrium isotherm data. Cadmium adsorption occurs rapidly and the adsorption mechanism is a chemical sorption via ionic exchange between the adsorbate and adsorbent. Thermodynamic parameters were also evaluated from the effect of temperature studies. Regenerability of NaS–OS material was ascertained by quantitative desorption of cadmium with 1 M aqueous NaCl and the reusability of the matrix after five repeated cycles led to nearly no attenuation in its performance (less than 2% in the sorption capacity), indicating that repeated use of NaS–OS is quite feasible. Compared to other low-cost adsorbents utilized for the removal of Cd(II) from water/wastewater, NaS–OS shows higher sorption capacity. These results have important implications for the design of low-cost adsorbents based on agricultural wastes. 相似文献
85.
Abdellah Sebbar 《Communications in Mathematical Physics》1998,198(2):283-309
In this paper a close connection is established between certain cohomology spaces of representations of the quantum affine
algebra , and a twisted $q$-de Rham (Jackson–Aomoto) cohomology of configuration spaces using the quantum screening operators.
Received: 24 December 1997 / Accepted: 2 April 1998 相似文献
86.
Hossni Ziyat My Youssef Ait Itto Mustapha Ait Ali Abdellah Karim Abdelkhalek Riahi Jean‐Claude Daran 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):o90-o93
The two new gem‐dihalogenocyclopropanes (1′S,3R)‐3‐(2′,2′‐dichloro‐1′‐methylcyclopropyl)‐6‐oxoheptanoic acid, C11H16Cl2O3, (2), and (1′S,3R)‐3‐(2′,2′‐dibromo‐1′‐methylcyclopropyl)‐6‐oxoheptanoic acid, C11H16Br2O3, (3), are isostructural. Both present two stereogenic centers at C1′ and C3. The absolute configuration was determined by X‐ray methods. The cyclopropyl rings are unsymmetrical, the shortest bond being distal with respect to the alkyl‐substituted C atom. 相似文献
87.
In the first part of the present study, an appropriate inflow turbulent boundary condition is chosen. Then, a comparison is
made between two turbulence models for a plasma jet discharged into air atmosphere. The plasma jet gas phase flow is predicted
with the standard k–ɛ model and the RNG model of turbulence. Particles behavior is modeled using stochastic particles trajectories.
A validation of the plasma jet model is made by comparison with experimental data. This part of the study shows that the flow
features are better predicted with the RNG model. The choice of appropriate boundary conditions seems to be crucial for a
better simulation of plasma thermal spraying. Afterwards, computations are performed for projection of Ni particles. It is
found that the computed particles velocities and temperatures are also better predicted with the RNG model compared with the
k–ɛ model. The second part of this study is concerned with the effect of the substrate movement on the gas flow field. This
is performed in order to simulate a realistic coatings process where a relative movement between the torch and the substrate
always exists. Three substrate velocities have been used and it is found that the flow fields are affected only very near
the substrate wall. 相似文献
88.
Soufiane El Houssame Hafid Anane Larbi El Firdoussi Abdellah Karim 《Central European Journal of Chemistry》2008,6(3):470-476
The palladium(0) catalyzed amination of allylic acetates and carbonates derivatives from terpenic olefins was carried out
under mild conditions. The reaction offers a very good method for the preparation of allylic amines and thus to provide a
useful entry to new functionalized terpenic olefin products. The mechanism involving a formation of p-allyl-palladium intermediate
complex is in good agreement with the results obtained with the optically active substrates, as well as via an analysis of
the observed regio-and stereoselectivity.
相似文献
89.
Hafid Anane Soufiane El Houssame Abdelali El Guerraze Abdeladim Guermoune Abderrahim Boutalib Abedellah Jarid Ignacio Nebot-Gil Francisco Tomás 《Central European Journal of Chemistry》2008,6(3):400-403
The complexation energies of H3BNHnCl3−n (n= 3-0) complexes and the proton affinities of NHnCl3−n compounds have been computed at the G2(MP2) level of theory. G2(MP2) results show that the successive chlorine substitution
on the ammonia decreases both the basicity of the NHnCl3−n ligands and the stability of H3BNHnCl3−n complexes. The findings are interpreted in terms of the rehybridisation of the nitrogen lone-pair orbital. The NBO partitioning
scheme shows that the variation of the N-H and N-Cl bond lengths, upon complexation, is due to variation of “s” character
in these bonds.
相似文献
90.