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排序方式: 共有242条查询结果,搜索用时 15 毫秒
141.
Sajjad Damiri Hamid Reza Pouretedal Amin Heidari 《International journal of environmental analytical chemistry》2016,96(11):1059-1073
An electrochemical oxidation route was developed for sensitive and selective assay of nitrotriazolone (NTO) explosive in some environmental samples on a multi-walled carbon nanotube (MWCNTs)/TiO2 nanocomposite paste electrode, for prevention of the analytical interference of conventional reducible energetic compounds. Detailed evaluations were made for the electrochemical behaviour of NTO on the modified electrode by adsorptive stripping voltammetry, electrochemical impedance spectroscopy (EIS) and chronoamperometry techniques in the pH range of 2.0–10.0. Parameters such as diffusion coefficient constant of NTO were calculated, and various experimental conditions were also optimised. Under optimal conditions the calibration curve had two linear dynamic ranges of 130.0–3251.5 μg L?1 and 6.5–26.0 mg L?1 with a detection limit of 26.0 μg L?1 (0.2 μmol L?1) and precision of <3%. This electrochemical sensor was further applied to determine NTO in real soil and water samples with satisfactory results. 相似文献
142.
Gulraiz Ahmad Nasir Rasool Adeel Mubarik Ameer Fawad Zahoor Muhammad Ali Hashmi Muhammad Zubair Muhammad Bilal Mohamed Hussien Muhammad Saeed Akhtar Sajjad Haider 《Molecules (Basel, Switzerland)》2021,26(23)
Synthesis of 5-aryl-N-(pyrazin-2-yl)thiophene-2-carboxamides (4a–4n) by a Suzuki cross-coupling reaction of 5-bromo-N-(pyrazin-2-yl)thiophene-2-carboxamide (3) with various aryl/heteroaryl boronic acids/pinacol esters was observed in this article. The intermediate compound 3 was prepared by condensation of pyrazin-2-amine (1) with 5-bromothiophene-2-carboxylic acid (2) mediated by TiCl4. The target pyrazine analogs (4a–4n) were confirmed by NMR and mass spectrometry. In DFT calculation of target molecules, several reactivity parameters like FMOs (EHOMO, ELUMO), HOMO–LUMO energy gap, electron affinity (A), ionization energy (I), electrophilicity index (ω), chemical softness (σ) and chemical hardness (η) were considered and discussed. Effect of various substituents was observed on values of the HOMO–LUMO energy gap and hyperpolarizability. The p-electronic delocalization extended over pyrazine, benzene and thiophene was examined in studying the NLO behavior. The chemical shifts of 1H NMR of all the synthesized compounds 4a–4n were calculated and compared with the experimental values. 相似文献
143.
Baghban Alireza Habibzadeh Sajjad Ashtiani Farzin Zokaee 《Journal of Thermal Analysis and Calorimetry》2019,135(1):507-522
Journal of Thermal Analysis and Calorimetry - In the present study, a comprehensive model based on least square support vector machine algorithm (LSSVM) was developed to estimate thermal... 相似文献
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145.
H. Abbastabar Ahangar G. H. Mahdavinia K. Marjani A. Hafezian 《Journal of the Iranian Chemical Society》2010,7(3):770-774
1,2-Dihydro-1-arylnaphtho[1,2-e][1,3]oxazine-3-one derivatives were synthesized in high yields using a facile and one-pot condensation of 2-naphthol, aromatic aldehydes and urea catalyzed by perchloric acid supported on silica under thermal solvent-free conditions. 相似文献
146.
Ahmad Shaabani Afshin Sarvary Sajjad Keshipour Ali Hossein Rezayan Rahim Ghadari 《Tetrahedron》2010,66(10):1911-1914
A new class of pyridinium, quinolinium, isoquinolinum, and N-methylimidazolium-3-(2,5-dihydro-5-oxofuran-3-yl)-4-hydroxyfuran-2(5H)-one salts have been prepared in high yields by reacting pyridine, quinoline, isoquinoline, N-methylimidazole, 1,4-diazabicyclo[2.2.2]octane, and their derivatives with tetronic acid in CH2Cl2. 相似文献
147.
Effect of number density on velocity distributions in a driven quasi-two-dimensional granular gas 下载免费PDF全文
The motion of mono-disperse spherical steel particles in a vibration driven quasi-two-dimensional (2D) square cell is studied. The cell is horizontally vibrated to eliminate the effect of gravity compaction. The velocity distributions at different particle number densities are studied and found to obey the form exp[-β(|vy|/σy)α], in which v y and σ y are velocity and its variance in the transverse direction, and α and β are fitting parameters. The value of α is found to decrease with the number density of particles increasing. To investigate the effect of the bottom plate, the molecular dynamics simulation without considering any bottom friction is performed. The accordance between the simulation result and the experimental result shows that the influence of bottom plate friction force on the high energy tail of the velocity distribution can be neglected. 相似文献
148.
149.
The coherent pion production induced by neutrinos in nuclei is studied using a delta hole model in the local density approximation taking into account the renormalization of Delta properties in a nuclear medium. The pion absorption effects are included in an eikonal approximation. These effects give a large reduction in the total cross section. The numerical results for the total cross section are found to be consistent with recent experimental results from the K2K and MiniBooNE Collaborations and other older experiments in the intermediate energy region. 相似文献
150.