Existence of mild solutions for semilinear differential equations with nonlocal and impulsive conditions

This paper is concerned with the existence of mild solutions for impulsive semilinear differential equations with nonlocal conditions. Using the technique of measures of noncompactness in Banach and Fréchet spaces of piecewise continuous functions, existence results are obtained both on bounded and unbounded intervals, when the impulsive functions and the nonlocal item are not compact in the space of piecewise continuous functions but they are continuous and Lipschitzian with respect to some measure of noncompactness, and the linear part generates only a strongly continuous evolution system.     

Density profiles of Ar adsorbed in slits of CO2: spontaneous symmetry breaking revisited

A recently reported symmetry breaking of density profiles of fluid argon confined by two parallel solid walls of carbon dioxide is studied. The calculations are performed in the framework of a nonlocal density functional theory. It is shown that the existence of such asymmetrical solutions is restricted to a special choice for the adsorption potential, where the attraction of the solid-fluid interaction is reduced by the introduction of a hard-wall repulsion. The behavior as a function of the slit's width is also discussed. All the results are placed in the context of the current knowledge on this matter.     

15N NMR coordination shifts in Pd(II), Pt(II), Au(III), Co(III), Rh(III), Ir(III), Pd(IV), and Pt(IV) complexes with pyridine, 2,2'-bipyridine, 1,10-phenanthroline, quinoline, isoquinoline, 2,2'-biquinoline, 2,2':6', 2'-terpyridine and their alkyl or aryl derivatives

The 15N NMR data for 105 complexes of Pd(II), Pt(II), Au(III), Co(III), Rh(III), Ir(III), Pd(IV), and Pt(IV) complexes with simple azines such as pyridine, 2,2'-bipyridine, 1,10-phenanthroline, quinoline, isoquinoline, 2,2'-biquinoline, 2,2':6', 2'-terpyridine and their alkyl or aryl derivatives have been reviewed. The 15N NMR coordination shifts, i.e. the differences between the 15N chemical shifts of the same nitrogen in the molecules of the complex and the ligand (Delta(15N) (coord) = delta(15N) (compl)--delta(15N) (lig)), have been related to some structural features of the reviewed coordination compounds, like the type of the central ion and the character of auxiliary ligands (mainly in trans position). These Delta(15N) (coord) parameters are negative, their absolute magnitudes (ca 30-150 ppm) generally increasing in the metal order Au(III) < Pd(II) < Pt(II) and Rh(III) < Co(III) < Pt(IV) < Ir(III), as well as with the enhanced trans influence of the other donor atoms (H, C < Cl < N).     

The crystal and molecular structure of potassium aquapentachloroiridate(III) and the H, C, N NMR coordination shifts in iridium(III) chloride complexes with 2,2′-bipyridine or 1,10-phenanthroline

The crystal and molecular structure of potassium aquapentachloroiridate(III) (K₂[Ir(H₂O)Cl₅]) was reported. The [Ir(H₂O)Cl₅]²⁻ anions are nearly octahedral, the axial Ir–Cl bond (2.322(2) Å) being shorter than the equatorial ones (2.346(2)–2.360(2) Å); the Ir–O bond length is 2.090(4) Å. Ir(III) chloride complexes with 2,2′-bipyridine (LL = bpy) or 1,10-phenanthroline (LL = phen), of the general formulae K[Ir(LL)Cl₄] and cis-[Ir(LL)₂Cl₂]Cl, were studied by far-IR and ¹H–¹³C, ¹H–¹⁵N HMBC/HMQC/HSQC–NMR. High-frequency ¹H NMR coordination shifts (Δ^1H_coord = δ^1H_complex − δ^1H_ligand; max. ca. +1 ppm) were noted for [Ir(LL)Cl₄]⁻ anions, while for cis-[Ir(LL)₂Cl₂]⁺ cations they had variable sign and magnitude (max. ca. ±1 ppm); they were dependent on the proton position, being mostly expressed for the nitrogen-adjacent hydrogens (H(6) for bpy, H(2) for phen). ¹³C NMR signals were high-frequency shifted (by max. ca. 8 ppm), whereas all ¹⁵N nuclei were shifted to the lower frequency (by ca. 105–120 ppm). The experimental ¹H, ¹³C, ¹⁵N NMR chemical shifts were reproduced by semi-empirical quantum-chemical calculations (B3LYP/LanL2DZ+6-31G^**//B3LYP/LanL2DZ+6-31G*).     

Tris(2-cyanoethyl)tin(IV) bromide and tris(2-cyanoethyl)tin(IV) iodide,their structure,properties and reactions with adenosine,AMP and ATP

Complexes [Sn(CH₂CH₂CN)₃I] (1) and [SnBr(CH₂CH₂CN)₃] (2) have been obtained by the oxidation reactions of hexakis(2-cyanoethyl)ditin(III) by means of iodine and bromine. The complexes have been characterized by NMR and IR spectroscopy methods and X-ray crystallography. Both compounds consist of zigzag single-strand chains with a bridging 2-cyanoethyl ligand coordinating via the CH₂ group and N atom. The tin atoms are in a distorted trigonal bipyramidal environment with bromo or iodo ligands and a nitrogen atom occupying the axial coordination sites. The Sn(1)–N(3i) distances in complexes 1 and 2 are considerably longer than the tin-equatorial ligand bonds. The molecular and electronic structures and IR spectra of [SnBr(CH₂CH₂CN)₃] mononuclear and [SnBr(CH₂CH₂CN)₃]₂ dinuclear fragments of the complex have been studied by the DFT B3LYP method. The calculated interatomic distances for the entity containing a five-coordinate tin atom agree well with those found crystallographically. The compounds in water solutions form trigonal bipyramidal complexes containing aqua and hydroxo axial ligands. The interaction of these complexes with adenosine, 5′-adenosine monophosphate and 5′-adenosine triphosphate has been investigated.     

Influence of electron beam irradiation on growth of Phytophthora cinnamomi and its control in substrates

Very extensive production procedure, especially in plants growing under covering, require methods, which would allow quick elimination or substantial reduction of populations of specific pathogens without affecting the growth and development of the cultivated plants. Among soil-borne pathogens, the Phytophthora species are especially dangerous for horticultural plants. In this study, irradiation with electron beam was applied to control Phytophthora cinnamomi. The influence of irradiation dose on the reduction of in vitro growth and the population density of the pathogen in treated peat and its mixture with composted pine bark (1:1), as well as the health of Chamaecyparis lawsoniana and Lavandula angustifolia plants were evaluated. Application of irradiation at a dose of 1.5 kGy completely inhibited the in vitro development of P. cinnamomi. This irradiation effect was connected with the disintegration of the hyphae and spores of the species. Irradiation of peat and its mixture with composted pine bark with 10 kGy resulted in the inhibition of stem base rot development in Ch. lawsoniana. Symptoms of the disease were not observed when the substrates were treated with 15 kGy. In the case of L. angustifolia, stem root rot was not observed on cuttings transplanted to infected peat irradiated at a dose of 10 kGy. Irradiation of the horticultural substrates did not affect plant growth.     

Porous alumina membranes with branched nanopores as templates for fabrication of Y-shaped nanowire arrays

Porous anodic alumina membranes with Y-branched and double-branched nanopores were fabricated by the stepwise reduction of anodizing potential during the second step of anodization carried out in 0.3 M oxalic acid. The process of nanoporous layer formation and influence of anodizing parameters on structural features of as-obtained anodic aluminum oxide (AAO) membranes were discussed in detail. The pore rearrangement process occurring after the potential decrease was investigated on the basis of the current density vs. time curves, and results were correlated with the field-emission scanning electron microscope images of the pore bottoms taken after different anodizing durations. It was found that the reorganization of nanopores begins after 600 and 500 s from the time of the potential reduction to 42 and 30 V and the process seems to be completed after about 900 and 800 s, respectively. The through-hole AAO membranes were used as templates for the fabrication of gold and polystyrene nanowires via electrochemical deposition and simple immersing in the polymer solution, respectively. The arrays of hierarchically branched nanowires were synthesized, and the dimensions of nanowires were consistent with the shape and structure of used AAO templates.

     

Neumann problems resonant at zero and infinity

We consider a semilinear Neumann problem with a reaction which is resonant at both zero and ±∞. Using a combination of methods from critical point theory, together with truncation techniques, the use of upper–lower solutions and of the Morse theory (critical groups), we show that the problem has at least five nontrivial smooth solutions, four of which have constant sign (two positive and two negative).     

Existence and multiplicity of solutions for second order periodic systems with the <Emphasis Type="Italic">p</Emphasis>-Laplacian and a nonsmooth potential

In this paper we study nonlinear periodic systems driven by the ordinary p-Laplacian with a nonsmooth potential. We prove an existence theorem using a nonsmooth variant of the reduction method. We also prove two multiplicity results. The first is for scalar problems and uses the nonsmooth second deformation lemma. The second is for systems and it is based on the nonsmooth local linking theorem.     

Microelectrode array fabricated in low temperature cofired ceramic (LTCC) technology

This work presents the development of a novel construction of an integrated microelectrode array. The device was fabricated on a ceramic support, with the use of low temperature cofired ceramics technology. Model potassium-selective membranes were applied on the surface of PdAg/AgCl electrodes formed on the ceramic substrate. The obtained microsensors exhibited very good repeatability, reproducibility, and sensitivity. The array of microelectrodes covered with polymeric layers of various selectivities was applied as an electronic tongue to differentiate between various diet supplements.