Spectral studies of heterocyclic β-diketonates of actinide,lanthanide, and transition metals

The results of absorption spectral studies of the 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone chelates of thorium, uranyl, neodymium, gadolinium, gallium, and iron are presented. These neutral chelates exhibit u.v. spectra very similar to that of the ligand, with slight bathochromic or hypsochromic shifts. The solution stability of the complexes in acetonitrile, ethanol, and chloroform was also studied and the lanthanide complexes were found to be the least stable. Sinha's parameter is calculated for the neodymium chelate to determine the relative degree of covalency upon complexation.     

Electrochemical biosensor based on supported planar lipid bilayers for fast detection of pathogenic bacteria

This paper presents a new ion-channel biosensor based on supported bilayer lipid membrane for direct and fast detection of Campylobacter species. The sensing element of a biosensor is composed of a stainless-steel working electrode, which is covered by artificial bilayer lipid membrane (BLM). Antibodies to bacteria embedded into the BLM are used as channel forming proteins. The biosensor has a strong signal amplification effect, which is defined as the total number of ions transported across the BLM. The total number of (univalent) ions flowing through the channels is 10¹⁰ ions s⁻¹. The biosensor showed a very good sensitivity and selectivity to Campylobacter species.     

A new tripod PPN bridging ligand and its copper,silver and palladium complexes: syntheses,characterizations and X-ray structures

A new tripod bridging ligand 2-{bis(diisopropylphosphino)methyl}-1-methylimidazole, MeImCH(Pi-Pr₂)₂ (PPN) was synthesized conveniently by reacting 2-{bis(trimethylsilyl)methyl}-1-methylimidazole and chlorodiisopropylphosphine. The dicationic dinuclear complex [Cu₂(PPN)₂][ClO₄]₂ (1) was prepared by the reaction of the ligand with [Cu(MeCN)₄]ClO₄ in acetonitrile. The reaction of the ligand with AgNO₃ in propane-2-ol followed by addition of NH₄PF₆ led to the formation of a similar type complex [Ag₂(PPN)₂][PF₆]₂ (2). The X-ray diffraction studies of 1 and 2 revealed a μ₂-η¹:η² tripod-like bonding of the PPN ligand, with one P and one N atom chelating to one metal ion and the remaining one P atom binds to another metal ion, affording a face-to-face type molecule. An eight-membered M₂P₄C₂ and a 10-membered M₂P₂N₂C₄ ring are thus formed with this new functional diphosphine ligand. In both complexes the two metal ions are held in very close proximity [2.6707 Å for 1 and 2.859(3) Å for 2]. Complex 1 underwent a rapid ligand exchange process in solution. Besides these dinuclear complexes the ligand also afforded a mononuclear palladium complex, [PdCl₂(PPN)] (3), when it was treated with an equimolar amount of [PdCl₂(PhCN)₂] in benzene. In 3 the ligand acts as a bidentate chelate through its two phosphorus atoms, leaving the imidazole donor dangling. On the other hand, a P,P-bridged dinuclear Pd(I) complex [Pd₂Cl₂(PPN)₂] (4) was achieved by reacting two moles of the ligand with one mole of [PdCl₂(PhCN)₂], followed by the addition of one mole of Pd(dba)₂ [dba=dibenzylideneacetone].     

The effect of soil particle size on soil radon concentration

It has been suggested in the literature that the radon concentration in the soil gas is related to the particle size distribution of the soil. This paper examines this relation. Radon concentration was measured in the soil on the Carboniferous limestone south of Buxton in Derbyshire, England, using the can technique. At each site, a sample of soil was taken at the bottom of the hole in which the dosimeter was placed to determine the particle size distribution.

The correlations between the raw values of radon concentration, soil particle size fractions and elevation were weak. Nevertheless, the kriged maps of radon, silt, clay and elevation showed some spatial relation to one another. The kriged estimates showed stronger correlations among these properties, especially between radon and elevation.     

The $$\phi ^{6}$$-model expansion method for solving the nonlinear conformable time-fractional Schrödinger equation with fourth-order dispersion and parabolic law nonlinearity

The \(\phi ^{6}\)-model expansion method combined with the conformable time-fractional derivative is applied in this paper for finding many new exact solutions including Jacobi elliptic function solutions, solitary wave solutions, trigonometric function solutions and other solutions to the nonlinear conformable time-fractional Schrödinger equation with fourth-order dispersion and parabolic law nonlinearity. This method presents a wider applicability for handling the nonlinear partial differential equations. Comparing our results with the well-known results are given.     

Fiber-wireless (FiWi) access network: Performance evaluation and scalability analysis of the physical layer

The fiber-wireless (FiWi) access network is a prestigious architecture for next generation (NG) access network. NG access networks are proposed to provide high data rate, broadband multiple services, scalable bandwidth, and flexible communication for manifold wireless end-users (WEUs). In this paper, the FiWi access network is designed based on a wavelengths division multiplexing/time division multiplexing passive optical network (WDM/TDM PON) at the optical backhaul with data rate of 2.5 Gb/s and wireless fidelity-worldwide interoperability for microwave access (WiFi–WiMAX) technologies at the wireless front-end along a 50 m–5 km wireless links with data rate of 54–30 Mb/s, respectively. The performance of the optical backhaul and the wireless front-end, in the proposed FiWi access network, has been evaluated in terms of bit error rate (BER), error vector magnitude (EVM), and signal-to-noise ratio (SNR) of the physical (PHY) layer. The scalability of the optical backhaul based on maximum split ratio of 1/32 for each wavelength channel and a fiber length of 24 km from the central office (CO) to the access point (AP) is analyzed with bit error rate (BER) of 10⁻⁹.     

CO(III)–NI(II) double substituted bismuth vanadate: synthesis,phase stabilization,and structural and electrical characterization

Samples of Co–Ni double substituted bismuth vanadate, BICO_0.20?x NI _x VOX (Bi₄Co_0.20???x ^(III)Ni _x ^(II)V_1.8O_{10.8???(x/2)???δ} ;0?≤?x?≤?0.20) were synthesized by standard solid state reactions. The influence of Ni substitution for Co on phase stabilization and oxide-ion performance have been investigated using X-ray powder diffraction, differential thermal analysis, and AC impedance spectroscopy. The high conducting γ′-phase was effectively stabilized at room temperature for compositions with x?≥?0.13 whose thermal stability increases with Ni content. The complex plane plots of impedance were typically represented at temperatures below 380 °C, suggesting a major contribution of polycrystalline grains to the overall electrical conductivity. The dielectric permittivity measurements revealed the fact that suppression of the ferroelectric transition is compositionally dependent. Interestingly, the maximum ionic conductivity at lower temperatures (～2.56?×?10^?4 S cm^?1 at 300 °C) was observed for the composition with x?=?0.13. However, a good agreement was generally found between the values of electrical conductivity and corresponding activation energies of conduction.     

Fractional Boundary Value Problems with Integral Boundary Conditions via Topological Degree Method

This paper examines the existence and uniqueness of solutions for the fractional boundary value problems with integral boundary conditions. Banach’s contraction mapping principle and Schaefer’s fixed point theorem have been used besides topological technique of approximate solutions. An example is propounded to uphold our results.