排序方式: 共有51条查询结果,搜索用时 62 毫秒
21.
Rehab Ali Ibrahim Laith Abualigah Ahmed A. Ewees Mohammed A. A. Al-qaness Dalia Yousri Samah Alshathri Mohamed Abd Elaziz 《Entropy (Basel, Switzerland)》2021,23(9)
With the widespread use of intelligent information systems, a massive amount of data with lots of irrelevant, noisy, and redundant features are collected; moreover, many features should be handled. Therefore, introducing an efficient feature selection (FS) approach becomes a challenging aim. In the recent decade, various artificial methods and swarm models inspired by biological and social systems have been proposed to solve different problems, including FS. Thus, in this paper, an innovative approach is proposed based on a hybrid integration between two intelligent algorithms, Electric fish optimization (EFO) and the arithmetic optimization algorithm (AOA), to boost the exploration stage of EFO to process the high dimensional FS problems with a remarkable convergence speed. The proposed EFOAOA is examined with eighteen datasets for different real-life applications. The EFOAOA results are compared with a set of recent state-of-the-art optimizers using a set of statistical metrics and the Friedman test. The comparisons show the positive impact of integrating the AOA operator in the EFO, as the proposed EFOAOA can identify the most important features with high accuracy and efficiency. Compared to the other FS methods whereas, it got the lowest features number and the highest accuracy in 50% and 67% of the datasets, respectively. 相似文献
22.
Based on the closed connections among the homogeneous balance (HB) method, Weiss-Tabor-Carneval (WTC) method and Clarkson-Kruskal (CK) method, we study Bäcklund transformation and similarity reductions of the variable coefficients variant Boussinesq system. In the meantime, new exact solutions also are found. 相似文献
23.
Wail Al Zoubi Abbas Ali Salih Al‐Hamdani I Putu Widiantara Rehab Ghalib Hamoodah Young Gun Ko 《Journal of Physical Organic Chemistry》2017,30(12)
New ligand 4‐((2‐Hydroxy1‐naphthyl) methylene amino)‐1.5‐dimethyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐one (HL) was synthesized from the reaction of 2‐hydroxy‐1‐naphthaldehyde and 4‐aminophenaz one. A complexes of this ligand [VO(II)(HL)(SO4)], [Pt(IV)(L)Cl3], [Re(V)(L)Cl3]Cl, and [M(II)(L)Cl] (M═Pd(II), Ni(II), Cu(II)) were synthesized. The resulted compounds were characterized by IR, NMR (1H and 13C), mass spectrometry, element analysis, and UV‐Vis spectroscopy. Additionally, the spectroscopic studies revealed octahedral geometries for the Re(V), Pt(IV) complexes, and square pyramidal for VO(II), square planar for Pd(II) complex, and tetrahedral for the Ni(II) and Cu(II) complexes. Thermodynamic parameters (ΔE*, ΔH*, ΔS*, ΔG*, and K) were calculated using from the TGA curve Coats‐Red fern method. Therefore, hyper Chem‐8 program has been used to predict structural geometries of compounds in the gas phase. Finally, the synthesized Schiff base and its metal complexes were screened for their biological activity against bacterial species, 2 Gram‐positive bacteria (Bacillus subtilis and Staphylococcus aureus) and 2 Gram‐negative bacteria (Escherichia coli and Pseudomonas aeruginosa). 相似文献
24.
Preparation and characterization of polyaniline/manganese dioxide composites via oxidative polymerization: Effect of acids 总被引:1,自引:0,他引:1
Ali H. Gemeay Ikhlas A. Mansour Rehab G. El-Sharkawy Ahmed B. Zaki 《European Polymer Journal》2005,41(11):2575-2583
Polyaniline/manganese dioxide (PANI/MnO2) composites have been chemically prepared by oxidative polymerization of aniline in acidic medium containing MnO2 as an oxidant. The acids used were; H2SO4, HNO3, HCl, and H3PO4 The prepared composites were characterized by SEM, elemental analysis, FT-IR, XRD, TGA, and magnetic susceptibility. XRD measurements of the composites revealed that the crystal structure of incorporated MnO2 undergone a distortion and converted into amorphous. Thus, the XRD pattern of PANI was predominate. The degree of crystallinity of the prepared composites is depended on the type of compensated acid anions and has the order; . This order is agrees with the order of crystallographic radii and the shape of the corresponding acid anions. From the value of point zero charge of MnO2 (pzc at pH ≈7.5) and FT-IR spectra, it was concluded that adsorbed acids anions on the oxide surface works as the charge compensator for positively charge PANI in the formation of PANI/MnO2. The content of PANI in the composite was depended on the type of acid used. Thermogravimetric study exhibited that the composite with low content of PANI has a higher thermal stability. Magnetic susceptibility measurements revealed that the composites has a diamagnetic properties. A schematic composition of the composites has been suggested. 相似文献
25.
Ahmed Rehab Ahmed Akelah Maisa M. El‐Gamal 《Journal of polymer science. Part A, Polymer chemistry》2002,40(14):2513-2525
A series of polymer–clay composites carrying metribuzin as herbicide moieties were prepared. Linear copolymers containing metribuzin via an imide linkage were prepared by the free‐radical polymerization of metribuzin monomer (N,N‐diacryloyl metribuzin) with different comonomers. The intercalation of the copolymers onto montmorillonite through a cationic exchange process was carried out and yielded metribuzin composite products. The prepared materials were characterized with a wide variety of analytical techniques, including gel permeation chromatography, NMR, IR, elemental microanalysis, gravimetric analysis (calcination), and swelling measurements. The release rates for the prepared materials were investigated in media of different pHs with an ultraviolet spectrophotometer. Also, these compounds were studied for the control of herb growth. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2513–2525, 2002 相似文献
26.
The chemical oxidation of aniline with ammonium peroxydisulfate to form polyaniline (PANI) films has been studied in different aqueous acid mediums such as HCl, HNO3, and H2SO4. The yield and the growth rate of the PANI film deposition were measured using the quartz crystal microbalance (QCM) technique. The effect of different salts such as KCl, NaNO3, and K2SO4 and their concentration on the yield and the growth rate of the film formation are investigated. The yield of PANI film deposition depends on the acid used and the type of salts as well as their concentrations. When HCl and HNO3 were used as media, the addition of salts with the same anion has no effect. However, when H2SO4 was used as media, the addition of salts with the same anions as the medium enhances the yield of PANI film deposition. The UV–visible spectra of the produced PANI films in the absence and presence of the salts are also studied. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
27.
A. Ramadan G. Soliman Sawsan S. Mahmoud Salwa M. Nofal Rehab F. Abdel-Rahman 《Journal of Saudi Chemical Society》2012,16(1):13-21
The possible toxicological effects and in vitro antioxidant activity of the ethanolic extracts of Crocus sativus and Propolis were investigated. Both extracts did not cause any mortalities or signs of toxicity in mice when administered orally at doses up to 5 g/kg b.wt. In the sub-chronic study; the tested extracts did not produce any significant change in liver and kidney functions of rats, following oral administration for 8 successive weeks at doses of 500 mg/kg b.wt. of each. Propolis showed remarkable in vitro antioxidant activity at concentrations of (40–100 mg/ml). In contrast, the ethanolic extract of C. sativus ethanolic extract showed weak antioxidant activity in concentrations of (1–10 mg/ml) while at concentrations of (20–100 mg/ml) failed to exhibit any antioxidant activity. It was concluded that: both extracts were non-toxic, as they did not cause any mortalities or signs of toxicity in mice when administered orally at doses up to 5 g/kg b.wt. Daily oral administration of C. sativus, Propolis ethanolic extracts alone or in combination for 8 successive weeks to rats was quiet safe and didn't cause any toxic changes in liver and kidney. Antioxidant study showed that Propolis ethanolic extract was a more potent antioxidant than C. sativus extract. 相似文献
28.
Omar A. Fathhalla Mosaad S. Mohamed Madeha A. Farag Rehab Sayed Ahmed Ismail 《Research on Chemical Intermediates》2013,39(8):3487-3505
This study aims at the synthesis and evaluation of the chemotherapeutic activity of a number of 9-substituted tetrahydroacridine derivatives. The starting material, acridine hydrazide, could be prepared through the interaction between cyclohexanone and anthranilic acid, then chlorination of the product, then condensation of the last compound with hydrazine hydrate. The structures of the new compounds were established by IR, 1H NMR, MS spectra, and elemental analysis in certain cases. Antitumor activities as a trial to obtain more effective and less toxic agents were evaluated. The antitumor activity results indicated that the selected tetrahydroacridine derivatives showed antitumor activity against the liver cancer (HEPG2) tumor cell line tested, but with varying intensities in comparison to the known anticancer drugs, 5-fluorouracil and doxorubicin. It was found that compound VIb was the most active and induced a marked growth inhibition (0.694 μg/ml concentration) in a dose-dependent manner against liver cancer (HEPG2), while compound XVIIIa was second in regards to the growth inhibition activity (2.97 μg/ml concentration). 相似文献
29.
30.
Using the machinery of Lie group analysis,the nonlinear system of coupled Burgers-type equations is studied.Using the infinitesimal generators in the optimal system of subalgebra of the said Lie algebras,it leads to two nonequivalent similarity transformations by using it we obtain two reductions in the form of system of nonlinear ordinary differential equations.The search for solutions of these systems by using the G'/G-method has yielded certain exact solutions expressed by rational functions,hyperbolic functions,and trigonometric functions.Some figures are given to show the properties of the solutions. 相似文献