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101.
Oxidative electrochemical detection is used for liquid chromatographic separation of polynuclear aromatic hydrocarbons (PAH's). The amperometric response is shown to be dependent on the working potential, ionic strength, flow rate, pH, temperature and pretreatment of the glassy carbon electrode surface. These experimental factors were optimized by choosing the maximum signal-to-noise ratio for anthracene and benz(a)-anthracene. The figures of merit (sensitivity, limit of detection and linear dynamic range) of six PAH's are reported and compared with ultraviolet absorption detection. Varying the applied potential gives the capability for selective detection. 相似文献
102.
Tungstate sulfuric acid (TSA)/KMnO4 as a novel heterogeneous system for rapid deoximation 总被引:1,自引:0,他引:1
Neat chlorosulfonic acid reacts with anhydrous sodium tungstate to give tungstate sulfuric acid (TSA), a new dibasic inorganic solid acid in which two sulfuric acid molecules connect to a tungstate moiety via a covalent bond. A variety of oximes were oxidized to their parent carbonyl compounds under mild conditions with excellent yields in short times by a heterogeneous wet TSA/KMnO4 in dichloromethane system. 相似文献
103.
Morteza Moniri 《Archive for Mathematical Logic》2010,49(3):291-300
In this paper we prove conservation theorems for theories of classical first-order arithmetic over their intuitionistic version.
We also prove generalized conservation results for intuitionistic theories when certain weak forms of the principle of excluded
middle are added to them. Members of two families of subsystems of Heyting arithmetic and Buss-Harnik’s theories of intuitionistic
bounded arithmetic are the intuitionistic theories we consider. For the first group, we use a method described by Leivant
based on the negative translation combined with a variant of Friedman’s translation. For the second group, we use Avigad’s
forcing method. 相似文献
104.
Saeed Balalaie Morteza Ashouriha Frank Rominger Hamid Reza Bijanzadeh 《Molecular diversity》2013,17(1):55-61
A three-component reaction of 3-formyl chromones, dialkyl acetylenedicarboxylate, and isocyanides in the presence of $\text{ POCl}_{3}$ was used as a highly efficient and practical approach for the synthesis of 3-amino-5-chromenyl-butenolides. High yields and high bond forming efficiency, and simple operations are the advantages of this method. Graphical abstract 相似文献
105.
Morteza Mohseni 《International Journal of Theoretical Physics》2008,47(4):1079-1082
We introduce a Lagrangian which can be varied to give both the equation of motion and world-line deviations of spinning particles
simultaneously. 相似文献
106.
Nonlinear vibration mitigation of a flexible rotor shaft carrying a longitudinally dispositioned unbalanced rigid disc 总被引:1,自引:0,他引:1
Nonlinear Dynamics - This study is dedicated to investigate the nonlinear dynamics of a system composed of a flexible rotor shaft carrying a longitudinally dispositioned unbalanced rigid disc. The... 相似文献
107.
An Object-Based Shale Permeability Model: Non-Darcy Gas Flow,Sorption, and Surface Diffusion Effects
Shale samples consist of two major components: organic matter (OM) and inorganic mineral component (iOM). Each component has its distinct pore network topology and morphology, which necessitates generating a model capable of distinguishing the two media. We constructed an object-based model using the OM and iOM composition of shale samples. In the model, we integrated information such as OM population and size distribution, as well as its associated pore-size distribution. For the iOM part, we used mineralogy and pore-size information derived from X-ray diffraction, scanning electron microscopy, and nitrogen sorption measurements. Our proposed model results in millimeter-scale 2D realizations of shale samples by honoring OM and mineral types, their compositions, shapes, and size distributions. The model can capture heterogeneities smaller than 1 mm. We studied the effects of different gas flow processes and found that Knudsen diffusion and gas slippage dominate the flow, but surface diffusion has little impact on total gas flow. 相似文献
108.
Meccanica - Passive micromixers, due to their relatively high mixing efficiency and simple fabrication, have wide applications in biological, medical, and chemical processes. Serpentine and... 相似文献
109.
An efficient green approach for the synthesis of N-cyclohexyl-3-aryl-quinoxaline-2-amine derivatives, via a three-component one-pot condensation reaction of o-phenylenediamine, aromatic aldehydes and cyclohexyl isocyanide in the presence of perlite–SO3H nanoparticles (diameter/thickness of platelets <?100 nm) under ultrasound irradiation has been demonstrated. The present method offers advantages such as shorter reaction time, easy work-up, excellent yields, recovery and reusability of catalyst. In addition, the methodology has been prosperous in getting the green chemistry purposes such as natural catalyst, using ultrasound irradiation instead of conventional heating and stirring, and a non-hazardous products in the thus combining the features of both economic and environmental advantages. 相似文献
110.
Maryam Mohebbi Peyman Salehi Morteza Bararjanian Samad N. Ebrahimi 《Journal of the Iranian Chemical Society》2018,15(1):47-53
In this paper, synthesis of two derivatives of noscapine and their application as organocatalysts in the asymmetric addition of diethylzinc to aromatic aldehydes is reported. The first catalyst (2) was synthesized by the reduction of lactone ring of noscapine to form the corresponding diol, and the second one (3) was prepared by tert-butyl dimethyl silylation of the primary hydroxyl group of 2. Excellent yields and high ees up to 95% were obtained by using 3 as the catalyst. To the best of our knowledge, this is the first report on the application of lactone ring opened noscapinoid compounds as organocatalysts in asymmetric reactions. 相似文献