Effects on RCS of perfect electromagnetic conductor (PEMC) sphere by coating with anisotropic plasma layer are studied in this paper. The incident, scattered and transmitted electromagnetic fields are expanded in term of spherical vector wave functions using extended classical theory of scattering. Co and cross-polarized scattered field coefficients are obtained at the interface of free space-anisotropic plasma and at anisotropic plasma-PEMC sphere core by scattering matrices method. The presented analytical expressions are general for any perfect conducting sphere (PMC, PEC, or PEMC) with general anisotropic/isotropic material coatings that include plasma and metamaterials. The behavior of the forward and backscattered radar cross section of PEMC sphere with the variation of the magnetic field strength, incident frequency, plasma density, and effective collision frequency for the co-polarized and the cross polarized fields are investigated. It is also observed from the obtained results that anisotropic layer on PEMC sphere shows reciprocal behavior as compared to isotopic plasma layer on PEMC sphere. The comparisons of the numerical results of the presented analytical expressions with available results of some special cases show the correctness of the analysis. 相似文献
Current state-of-the-art implantable micron feature electronic devices are capable of monitoring and stimulating functions in vivo. Within an EU Framework VI project a further step was taken in developing key microsystem technologies and communication methods that could bring intelligence directly to the human interface, in the form of reactive medical implants and ambulatory measurement systems. Information from these devices is planned to be transmitted out into the wider environment for remote processing. However, the packaging of such state-of-the-art devices to enhance tissue biocompatibility, and to protect conducting elements from in vivo corrosion during extended use, along with protecting the body from toxins leaching from implant components, remains a concern. Candidate polymeric barriers as hydration resistant and solute impermeable interfaces to mitigate such major problems of chronic implantation were investigated. Materials studied included silicone rubber, PVC, polyurethane, and diamond-like carbon (DLC). Polymer permeability to water solutes was marginally improved through incorporation of lipid into these structures. Surface biocompatibility was assessed on the basis of protein film deposition in vitro and by cell viability studies in tissue culture. Short-term toxicity was not observed for any of the tested materials, though there were substantial differences in hydration. Additionally, polypyrrole over active electrodes shows feasibility for controlled tissue interfacing whilst retaining electrical conductivity. 相似文献
Optical emission spectroscopy is used to investigate the effect of neon mixing on the electron temperature and vibrational temperature of second positive and first negative system of nitrogen plasma generated by 13.56 MHZ RF generator. The electron temperature is determined from NeI lines intensities, using Boltzman's plot. The relative changes in vibrational population of N2(C3Πu) and states with neon mixing are monitored by measuring the emission intensities of second positive and first negative system of nitrogen molecules. Vibrational temperature is calculated for the sequences Δν=0,1,−2, that follows the Boltzman's distribution. It is found that electron temperature as well as vibrational temperature of second positive and first negative system can be raised significantly by mixing neon in nitrogen plasma. Vibrational temperature at 250 watt RF power, of second positive system is raised up to 0.67 eV at 90% neon where as for first negative system it is raised up to 0.78 eV. It is found that vibrational temperature increases with the gas pressure. 相似文献
This paper study the dynamics of optical solitons for nonlinear directional couplers. This coupler system is considered with the group velocity dispersion and the cross-phase modulation of two components along with the spatiotemporal dispersion coefficients. The constraint conditions for the existence of optical Gaussons and dark solitons are listed under the log law and Kerr law nonlinearities, repectively. Additionally, a couple of other solutions known as singular periodic and combined dark-singular solitons, fall out as a by-product of this scheme. This scheme however fails to retrieve bright soliton solution. 相似文献
Thermal ionization mass spectrometry has been used for the determination of isotopic composition of boron in natural samples, like water, with an improved degree of accuracy and precision. After concentration and separation boron is treated with an excess of sodium hydroxide in order to convert it completely to sodium metaborate. The excess of sodium hydroxide present in the sample causes problems in the isotopic analysis. This excess is neutralized with 0.1M nitric acid on the filament while loading the sample by a special technique. This procedure improves the precision and accuracy of the analysis to a large extent. 相似文献
The study of interactions between surfactant and salt in aqueous solutions has attracted significant interest in recent years because of their widespread applications and relatively complex behavior. This work reports the systematic study of surface phenomenon and self-aggregation behavior of cationic surfactant cetyltrimethyl ammonium bromide (CTAB) with ammonium nitrate (NH\begin{document}$ _4 $\end{document}NO\begin{document}$ _3 $\end{document}) salt. Surface and thermodynamic properties of cationic surfactant CTAB with NH\begin{document}$ _4 $\end{document}NO\begin{document}$ _3 $\end{document} were investigated at different temperatures using different techniques such as conductometry and surface tensiometery. The surface tension measurement was carried out to find out the critical micelle concentration, free energy of adsorption, free energy of micellization, minimum area per molecule, and surface excess concentration. The study reveals that the process of micellization is spontaneous and exothermic in nature. Conductance measurement was carried out to determine critical micelle concentration, degree of ionization and degree of counter ion binding. Addition of NH\begin{document}$ _4 $\end{document}NO\begin{document}$ _3 $\end{document} to the surfactant solutions increase the values of degree of ionization and degree of counter ion binding, although it lowers the values of critical micelle concentration showing that the process of micellization is more favorable and spontaneous. The study is very helpful to develop better understanding about interaction between electrolyte and surfactant, which are used in many applications and in different processes (e.g., pharmaceutical, industrial foaming, drug solubilization, oil recovery, and medium for metal nanoparticle formation). 相似文献
Structural geometry, electronic band gaps, density of states, optical and mechanical properties of double perovskite halides Cs_2InBiX_6(X = F, Cl, Br, I) are investigated using the density functional theory. These compounds possess genuine perovskite stoichiometry, evaluated using various geometry-based indices like tolerance factor, octahedral factor, and formation energy. The fundamental electronic band gaps are direct and valued in the range 0.80–2.79 e V. These compounds have narrow band gaps(except Cs_2InBiX_6) due to strong orbital coupling of the cations. The valence band maximum and conduction band minimum are confirmed to be essentially of In 5 s and Bi 6 p characters, respectively. The splitting of Bi 6 p bands due to strong spin-orbit coupling causes reduction in the band gaps. These compounds have large dispersion in their bands and very low carrier effective masses. The substitution of halogen atoms has great influence on the optical properties. The mechanical properties reveal that Cs_2InBiX_6(X = F, Cl, Br, I) satisfy the stability criteria in cubic structures. 相似文献
Plasma Chemistry and Plasma Processing - In this work, qualitative as well as the quantitative study of nutritional and trace toxic metals in various dry milk powders (local and branded) available... 相似文献
Zn(II) complexes of N-(quinolin-8-yl)picolinamide (HL1) (1) and N2,N6-di(quinolin-8-yl)pyridine-2,6-dicarboxamide (H2L2) (2) have been synthesized by deprotonation of the ligands and characterized by IR, NMR, and Single crystal X-ray crystallography. The mononuclear [Zn(L1)2] (3) and homodinuclear [Zn2(L2)2] (4) complexes are characterized by distorted octahedral geometries stabilized by hydrogen bonding and weak π···π interaction. The complexes demonstrate intense fluorescence bands in comparison with their corresponding ligands with well-distinguished intensity. The complexes act as efficient catalysts in various transesterification reactions. Among those, the best results have been achieved with complex 3 in conversion of 4-nitrophenylacetate into methyl acetate within 3 h.