Quantum Squeezing of Dark Solitons in Optical Fibers

The quantum theory of dark soliton propagation in fibers is studied based on the linearization approximation. Then the uncertainties in photon number, phase, position (time) and momentum of quantized dark solitons are calculated. Finally, the squeezing of the dark soliton is investigated by using homodyne detection and compared with bright soliton case.     

Calculation of transport properties and intermolecular potential energy function of the binary mixtures of H2 with Ne,Ar, Kr and Xe by a semi-empirical inversion method

The present paper contains inspection of the improved corresponding states principle for transport properties of hydrogen and the binary mixtures of hydrogen with Ne, Ar, Kr and Xe. The set of corresponding states parameters has been defined by a complex numerical analysis of a carefully selected body of experimental data. The obtained correlations for the reduced orientation-averaged diffusion and viscosity collision integrals are restricted to low densities in a temperature range from T = ?/k to the onset of ionization. These equations have been inverted directly to give the isotropic and effective intermolecular potential energy curve for binary mixtures of H₂ with Ne, Ar, Kr and Xe corresponding to the viscosity collision integrals. The results are then used to obtain the best Morse-Spline-Van der Waals (MSV) potential parameters. Our inverted potential energies have been compared with experimental intermolecular potentials that were obtained by molecular beam scattering and infrared spectroscopic measurements. In this research, the Chapman–Enskog and Wang Chang-Uhlenbeck-de Boer (WCUB) version of kinetic theory have been used in conjunction with our inverted potential energies to reproduce viscosity, diffusion, thermal conductivity and thermal diffusion factor of binary mixtures of H₂ with Ne, Ar, Kr and Xe in a wide temperature range for equimolar composition. As the deviation plots illustrate, our obtained intermolecular potential energies (on the basis of the algorithm presented in the inversion process) represent the low-density transport properties of binary mixtures of H₂ with Ne, Ar, Kr and Xe within their expected experimental uncertainties. Close agreement between the predicted values and the literature results of transport properties demonstrates the predictive power of the inversion scheme.     

Coating Strategies Using Layer‐by‐layer Deposition for Cell Encapsulation

The layer‐by‐layer (LbL) deposition technique is widely used to develop multilayered films based on the directed assembly of complementary materials. In the last decade, thin multilayers prepared by LbL deposition have been applied in biological fields, namely, for cellular encapsulation, due to their versatile processing and tunable properties. Their use was suggested as an alternative approach to overcome the drawbacks of bulk hydrogels, for endocrine cells transplantation or tissue engineering approaches, as effective cytoprotective agents, or as a way to control cell division. Nanostructured multilayered materials are currently used in the nanomodification of the surfaces of single cells and cell aggregates, and are also suitable as coatings for cell‐laden hydrogels or other biomaterials, which may later be transformed to highly permeable hollow capsules. In this Focus Review, we discuss the applications of LbL cell encapsulation in distinct fields, including cell therapy, regenerative medicine, and biotechnological applications. Insights regarding practical aspects required to employ LbL for cell encapsulation are also provided.     

Best proximity points,cyclic Kannan maps and geodesic metric spaces

We introduce the concept of cyclic Kannan orbital C-nonexpansive mappings and obtain the existence of a best proximity point on a pair of bounded, closed and convex subsets of a strictly convex metric space by using the geometric notion of seminormal structure. We also study the structure of minimal sets for cyclic Kannan C-nonexpansive mappings and show that results similar to the celebrated Goebel– Karlovitz lemma for nonexpansive self-mappings can be obtained for cyclic Kannan C-nonexpansive mappings.     

An essentially saturated surface not of Kahler type

It is shown that if X is an Inoue surface of type S_M then theirreducible components of the Douady space of Xⁿ are compact,for all n 0. This gives an example, sought by Moosa [J. ReineAngew. Math. 586 (2005) 1–20], of an essentially saturatedcompact complex manifold (in the sense of model theory) thatis not of Kähler type. Among the known compact complexsurfaces without curves, these are the only examples.     

Synthesis and Characterization of Novel Monoazo Naphthalimide Disperse Dyes Containing Carboxylic Acid Group with High Heat Fastness Properties

A group of novel monoazo disperse dyes containing carboxylic acid‐1,8‐naphthalimide group has been synthesized. All intermediates and dyes were purified by recrystalization and the column chromatography method. The purified products were characterized by ¹H NMR, ¹³C NMR, FTIR, DSC, UV‐VIS and Elemental Analysis. Spectrophotometric investigations of the synthesized dyes in different solvents were carried out in order to obtain their absorption maxima, molar extinction coefficients and solvatochromic effects. The absorption maxima of the synthesized dyes in acetone varied (513‐549 nm) and the molar extinction coefficient was (17405‐38939 l/mol cm). By changing the media from chloroform to DMF, the solvatochromism effect for all dyes increased. Dispersion of the synthesized dyes was prepared in water containing dispersing agent and applied to polyester fabrics. The dyed fabrics showed that all of the synthesized dyes were suitable for coloring polyester fibers, producing deep red to bluish red with very good fastness properties.     

A thermodynamic study of interaction of Ag+, Mg2+, Ca2+, and K+ cations with 4-hydroxyphenyl-2,5-bis(2-benzofuranyl)pyridine in some binary mixed non-aqueous solvents

In the present work the complexation process between Ag⁺ and Mg²⁺ cations and 4-hydroxyphenyl-2,5-bis(2-benzofuranyl)pyridine (HBFPY) ligand was studied in pure dimethylformamide (DMF), ethanol (EtOH), acetonitrile (AN) and in (DMF-EtOH), (AN-EtOH) and (DMF-AN) binary mixed solvent solutions at different temperatures using the conductometric method. Also in this work the complexation reaction between Ca²⁺, K⁺ cations and HBFPY ligand, was studied in pure dimethylformamide (DMF), propanol (PrOH), 1,4-dioxane (DOX), ethanol (EtOH) and in DMF-PrOH, DMF-DOX and DMF-EtOH binary mixed solvent solutions at different temperatures using the conductometric method. The conductance data show that the stoichiometry of the complexes formed between this ligand and the studied cations is 1 : 1 [ML]. In most cases, addition of HBFPY to solutions of these cations, causes a continuous increase in the molar conductivities which indicates that the mobility of complexed cations is more than the uncomplexed ones. The stability constants of the complexes were obtained from fitting of molar conductivity curves using a computer program, GENPLOT. The stability constant of [Mg(HBFPY)]²⁺ complex in various neat solvents at 15°C decreases in order: EtOH > DMF > AN and the stability constant of [Ag(HBFPY)]⁺ complex in various neat solvents at 35°C decreases in order: DMF > EtOH. The values of standard enthalpy changes (ΔH° _c ) for complexation reactions were obtained from the slope of the Van’t Hoff plots and the changes in standard entropy (ΔS° _c ) were calculated from the relationship ΔH° _c,295.15= ΔH° _c –298.15ΔS° _c .     

Sharp thresholds for constraint satisfaction problems and homomorphisms

We determine under which conditions certain natural models of random constraint satisfaction problems have sharp thresholds of satisfiability. These models include graph and hypergraph homomorphism, the (d,k,t)‐model, and binary constraint satisfaction problems with domain size three. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008     

A Polymorphic Azobenzene Cage for Energy-Efficient and Highly Selective p-Xylene Separation

Developing the competence of molecular sorbents for energy-saving applications, such as C8 separations, requires efficient, stable, scalable, and easily recyclable materials that can readily transition to commercial implementation. Herein, we report an azobenzene-based cage for the selective separation of p-xylene isomer across a range of C8 isomers in both vapor and liquid states with selectivity that is higher than the reported all-organic sorbents. The crystal structure shows non-porous cages that are separated by p-xylene molecules through selective CH–π interactions between the azo bonds and the methyl hydrogen atoms of the xylene molecules. This cage is stable in solution and can be regenerated directly under vacuum to be used in multiple cycles. We envisage that this work will promote the investigation of the azo bond as well as guest-induced crystal-to-crystal phase transition in non-porous organic solids for energy-intensive separations.