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1.
Isoquercitrin is a flavonoid chemical compound that can be extracted from different plant species such as Mangifera indica (mango), Rheum nobile , Annona squamosal , Camellia sinensis (tea), and coriander ( Coriandrum sativum L.). It possesses various biological activities such as the prevention of thromboembolism and has anticancer, antiinflammatory, and antifatigue activities. Therefore, there is a critical need to elucidate and predict the qualitative and quantitative properties of this phytochemical compound using the high performance liquid chromatography (HPLC) technique. In this paper, three different nonlinear models including artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine (SVM),in addition to a classical linear model [multilinear regression analysis (MLR)], were used for the prediction of the retention time (tR) and peak area (PA) for isoquercitrin using HPLC. The simulation uses concentration of the standard, composition of the mobile phases (MP-A and MP-B), and pH as the corresponding input variables. The performance efficiency of the models was evaluated using relative mean square error (RMSE), mean square error (MSE), determination coefficient (DC), and correlation coefficient (CC). The obtained results demonstrated that all four models are capable of predicting the qualitative and quantitative properties of the bioactive compound. A predictive comparison of the models showed that M3 had the highest prediction accuracy among the three models. Further evaluation of the results showed that ANFIS–M3 outperformed the other models and serves as the best model for the prediction of PA. On the other hand, ANN–M3proved its merit and emerged as the best model for tR simulation. The overall predictive accuracy of the best models showed them to be reliable tools for both qualitative and quantitative determination.  相似文献   
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3.
The results of new studies of creating protective oxide coatings based on Al2O3 (Si, Mn) and deposited onto aluminum alloys using electrolyte-plasma oxidation are presented. An analysis is performed by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), X-ray diffraction, Rutherford backscattering of 4He+ and protons, nanoindentation, scratching, friction coefficient measurements, and acoustic emission measurements. The results demonstrate that the deposited coatings have a high quality, hardness, and wear resistance and a low thermal diffusivity. Apart from Al2O3, the coatings are found to have Si, Mn, C, and Ca. The stoichiometry of the coatings is determined. The density and hardness of the coatings are close to those of ??-Al2O3 in the coating on an Al-Cu (D-16) substrate, and these values of the coating on an Al-Mg (S006) are lower by a factor of 1.5.  相似文献   
4.
Exciplex bands in the electroluminescence (EL) spectra of electroluminescent devices based on the new zinc complexes of amino-substituted benzothiazoles and in the photoluminescence (PL) spectra of the blends of a zinc complex and the triphenylamine derivative are studied. For the EL spectra, it is found that the relation between the exciplex bands and the intrinsic bands of the zinc complex emission depends on the thickness of layers in the EL devices and on the applied voltage. For the PL spectra of blends, this relation strongly depends on the concentration of components.  相似文献   
5.
The synthesis and properties of a new class of electroluminescent metal complexes based on quinoline ligands containing the sulfanylamino group in position 8 are described. These complexes contain C-N-M-N chains in the chelate cycles instead of the traditionally used C-O-M-N chains.  相似文献   
6.
Features of the photoconductivity of films of composites based on [2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] with additions of zinc 2,3,9,10,16,17,23,24-octabutylphthalocyanine and C60 were studied. Luminescence quenching and an increase in the photoconductivity with the addition of C60 to their composition were detected. The increase in the photoconductivity is connected with the capture of electrons and their transport along the C60 molecules. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 5, pp. 271–275, September–October, 2006.  相似文献   
7.
High-spin organic molecules with dominant spin-orbit contribution to magnetic anisotropy are reported. Quintet 4-azido-3,5-dibromopyridyl-2,6-dinitrene (Q-1), quintet 2-azido-3,5-dibromopyridyl-4,6-dinitrene (Q-2), and septet 3,5-dibromopyridyl-2,4,6-trinitrene (S-1) were generated in solid argon matrices by ultraviolet irradiation of 2,4,6-triazido-3,5-dibromopyridine. The zero-field splitting (ZFS) parameters, derived from electron spin resonance spectra, show unprecedentedly large magnitudes of the parameters D: ∣D(Q1)∣ = 0.289, ∣D(Q2)∣ = 0.373, and ∣D(S1)∣ = 0.297 cm(-1). The experimental ZFS parameters were successfully reproduced by density functional theory calculations, confirming that magnetic anisotropy of high-spin organic molecules can considerably be enhanced by the "heavy atom effect." In bromine-containing high-spin nitrenes, the spin-orbit term is dominant and governs both the magnitude and the sign of magnetic anisotropy. The largest negative value of D among septet trinitrenes is predicted for 1,3,5-trinitrenobenzene bearing three heavy atoms (Br) in positions 2, 4, and 6 of the benzene ring.  相似文献   
8.
2,4,6‐Triazido‐3,5‐dibromopyridine reacts with an equimolar amount of triethyl phosphite in ether at room temperature chemoselectively on the γ‐azido group to form 2,6‐diazido‐3,5‐dibromo‐4‐triethoxyphosphoriminopyridine as a single product. The latter adds another molecule of triethyl phosphite to give a mixture of 6‐azido‐2,4‐bis(triethoxyphosphorimino)‐3,5‐dibromopyridine and its tetrazolo[1,5‐a]pyridine isomer, the acidic hydrolysis of which affords 6‐azido‐2,4‐bis(diethoxyphosphoramino)‐3,5‐dibromopyridine. The study shows that the Staudinger‐phosphite reactions with heterocyclic polyazides occur selectively on the most electron‐deficient azido groups, opening up new prospects for preparation of new polyfunctional heterocyclic compounds.  相似文献   
9.
Russian Chemical Bulletin - Two new compounds from the class of bis(3-halopropionyl)amides were synthesized by the reaction of 3-halopropionyl chloride with N,N′-dimethylethylenediamine....  相似文献   
10.
Russian Physics Journal - Results of theoretical and experimental studies of exciplex of a zinc complex Zn(DFP-SAMQ)2 with the hole-transporting layer of NPD are presented. It is shown that at...  相似文献   
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