The investigation of TM wave propagation inside a cylindrical waveguide composed of antiferromagnetic/nonmagnetic superlattices (LANS), bounded by left-handed material (LHM), is presented. We have derived the eigenmode equation and obtained the solutions for TM propagation modes. We found that the waveguide supports backward TM waves since both electric permittivity and magnetic permeability of the LHM are negative. We also illustrated the dependence of the wave index nx on the magnetic fraction f1 and the reduced radius of the LANS. The largest propagation lengths of TM waves and the best confinement are achieved for the thinnest LANS of less magnetic material. Moreover, we displayed the influence of the magnetic permeability μh and the electric permittivity εh of the LHM on the power flow of TM waves. Larger wave indices have been switched by increasing μh and εh. 相似文献
The properties of the negative parity states of55Fe and57Fe are investigated in the framework of the intermediate coupling model. In the model, a neutron or a quasineutron is coupled to anharmonic vibrations of the core. Anharmonicities of the vibrations are estimated through the observed properties of the core. Energy levels, spectroscopic factors and electromagnetic properties have been calculated. The results of the present calculations are also compared with available experimental results and other theoretical results. The model reasonably accounts for many of the properties of the low-lying states. 相似文献
Excitation and emission phosphorescence spectra, lifetimes, and relative quantum yields of benzene and ten monosubstituted benzenes were determined at 77 K in methanol/water 10/90 v/v and in sodium iodide/methanol/water solutions. Substituents CHO, COCH(3), COC(2)H(5), OH, OCH(3), H(3), C(2)H(5), CH(2)OH and N(CH(3))(2) were investigated. Aqueous sodium iodide solutions were found to be a suitable heavy-atom solvent for phosophorimetry. Heavy-atom enhancement factors ranged from 1.2 to 8.3 according to the molecular structure and a marked decrease of the lifetime was observed for nine compounds in aqueous sodium iodide solution. A linear log-log correlation was obtained between the relative corrected phosphorescence signal and the heavy-atom enhancement factor of the monosubstituted benzenes. A similar correlation was found between the quantum yields and the heavy-atom enhancement factors. The analytical usefulness of these correlations is evident for the prediction of the magnitude of the heavy-atom effect. 相似文献
TheK-conversion coefficient of the 321 keVE1 transition in Hf177 has been measured by means of an iron free double focusing beta-ray spectrometer, using the internalexternal conversion method. The result obtained for αK(321)=0.162±0.016 is in disagreement with the theoretical values for pureE1 transition (αK=0.0154) calculated bySliv andBand. The large anomaly observed in theK-conversion process of the inhibitedE1 transition is compatible with a largeM2 admixture or, more probable with the presence of penetration matrix elements. 相似文献
Starch-acrylic acid-co-vinyl sulfonic acid/multiwalled carbon nanotubes (starch-AA-VSA/f-MWCNTs) bionanocomposite was successfully synthesized using gamma radiation for initiate the grafting of AA/VSA on starch in the presence of f-MWCNTs by template polymerization technique. The structural characteristics were confirmed by FTIR, SEM, and TGA. The adsorption behaviors of bionanocomposite toward Eu(III) and Cs(I) were examined using the batch adsorption experiments. Langmuir and Freundlich’s models were used to fit the experimental data of the adsorption isotherms. Kinetic studies showed that the adsorption data followed the pseudo-second-order model. Thermodynamic studies indicated that the reaction was favorable at high temperature and endothermic process.
Transition Metal Chemistry - Eight ruthenium complexes having thioalkyl-azoimine (SNN) ligands of two general types have been synthesized: (a) [Ru(L)(bipy)Cl](PF6) where {bipy = bipyridine,... 相似文献
Structural Chemistry - The [4+2] cycloaddition reaction of 1,3-dimethylindole and ortho-quinone methide (obtained from tautomerization of 2,6-dimethylquinone under basic conditions), experimentally... 相似文献
Russian Journal of Applied Chemistry - Industrial by product dumped from iron making industry (slag) has been modified by various chemical agents, particularly, paraffin wax, liquid nitrile... 相似文献
In this work, an electromembrane extraction (EME) technique was used for the extraction and determination of gold from water samples prior to UV-Vis spectrophotometry. An artificial neural network (ANN) combined with imperialist competitive algorithm (ICA) has been applied to optimize the EME. The effective parameters including pH of acceptor phase, extraction time (t), volume of sample solution (V), stirring rate (S), and voltage (E) were chosen as input variables and the extraction recovery of gold was considered as output variable. The mean of squared error (i.e., 0.0009) and determination coefficient (i.e., 0.9821) were applied to estimate the performance of the ANN model. The limit of detection was 4.5?µg L?1 (S/N?=?3) on the optimized variables. The intra- and interday precisions (%) were found to be 6.7% and 2.6%, respectively. This technique was then applied for analysis of gold from environment water samples. 相似文献