A New Route to N‐Aryl 2‐Alkenamides,N‐Allyl N‐Aryl 2‐Alkenamides,and N‐Aryl α,β‐Unsaturated γ‐Lactams from N‐Aryl 3‐(Phenylsulfonyl)propanamides

A series of N‐aryl 2‐alkenamides were produced efficiently by treating N‐aryl 3‐(phenylsulfonyl)‐propanamides with potassium tert‐butoxide in THF at 0°C. With out isolation, it was further treated with an additional equivalent of potassium tert‐butoxide and allyl bromide to give N‐allyl N‐aryl 2‐alkenamides in one pot in good yields. Followed by a ring‐closing metathesis reaction, these N‐allyl N‐aryl 2‐alkenamides were respectively converted into corresponding N‐aryl α,β‐unsaturated γ‐lactams in moderate yields.     

A quasi-residual principle in regularization for a common solution of a system of nonlinear monotone ill-posed equations

In this paper we study the Browder–Tikhonov regularization method for finding a common solution for a system of nonlinear ill-posed equations with potential, hemicontinuous and monotone mappings in Banach spaces. We give a principle, named quasi-residual, to choose a value of the regularization parameter and an estimate of convergence rates for the regularized solutions.     

Novel fluorescent amphiphilic poly(allylamine) and their supramacromolecular self‐assemblies in aqueous media

Fluorescent amphiphilic polymers were produced by grafting different types and levels of hydrophobic pendant groups with intrinsic fluorescent properties (fluorenylmethoxy carbonyl (Fmoc), dimethylamino‐1‐naphthalenesulfonyl (Dansyl), and naphthalene (Naphth) to a water soluble homopolymer backbone, polyallylamine (PAA). Non‐fluorescent hydrophobic pendant group (cholesteryl moieties) were also grafted onto PAA. The polymers were characterized with elemental analysis, NMR and FTIR spectroscopy. All polymers formed self‐assemblies by probe sonication in water with sizes ranging from 120 to 199 nm and TEM images showed the presence of spherical particles. The critical aggregation concentration (CAC) varied from 0.093 to 1.5 mg ml^?1 depending on the type of hydrophobic pendant groups. The Cholesteryl and Dansyl polymers showed the presence of one CAC while the Fmoc and Naphth grafted polymers revealed the presence of two CACs. The first CAC observed was possibly due to intermolecular aggregation while the second CAC at the higher polymer concentration was the result of excimer formation revealed by their fluorescent spectra. We reasoned that Naphth and Fmoc aromatic pendant groups possess a flat stereochemistry, thus allowing π–π stacking at higher concentrations. The presence of the N‐dimethylamino group in the Dansyl moiety gives rise to a 3D structure, thus hindering any stacking. The understanding of the supramolecular assemblies formed by these fluorescent amphiphilic polymers will aid in the engineering of advanced materials with superior functionality for biomedical applications. Copyright © 2011 John Wiley & Sons, Ltd.     

Regularization methods for nonlinear Ill-posed equations involving m-accretive mappings in Banach spaces

In this paper we prove strong convergence of the Browder-Tikhonov regularization method and the regularization inertial proximal point algorithm to a solution of nonlinear ill-posed equations involving m-accretive mappings in real, reflexive, and strictly convex Banach spaces with a uniformly Gâteaux differentiable norm without weak sequential continuous duality mapping.     

Effects of annealing temperature on ultra-low dielectric constant SiO2 thin films derived from sol-gel spin-on-coating

The results of ultra-low dielectric constant (k) SiO₂ films, derived from sol-gel spin-on-coating process using a combination of tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) (mole ratio of TEOS:MTES=4:1), have been reported. The effects of post deposition annealing temperature (300-500 °C for 30 min in argon ambience) on the physical, chemical, and electrical properties of the oxide have been systematically investigated. Filmetric system, Fourier transform-infrared spectroscope, X-ray diffraction system, atomic force microscope, and field-emission scanning electron microscope with energy dispersive X-ray have been employed for physical and chemical analyses. Electrical property of the oxide, in terms of leakage current through the oxide, has also been investigated. The oxide, annealed at 500 °C, produced the lowest dielectric constant value (k=2.3) and the lowest leakage current with no obvious oxide breakdown. The explanation of this observation has been discussed.     

Newton-Kantorovich Iterative Regularization for Nonlinear Ill-Posed Equations Involving Accretive Operators

The Newton-Kantorovich iterative regularization for nonlinear ill-posed equations involving monotone operators in Hilbert spaces is developed for the case of accretive operators in Banach spaces. An estimate for the convergence rates of the method is established.__________Published in Ukrains’kyi Matematychnyi Zhurnal, Vol. 57, No. 2, pp. 271–276, February, 2005.     

Tetrameric di­chloro­(tri­methyl­ammonio‐p‐toluene­sulfonamidate)­mercury(II)

In the title compound, hexa‐μ‐chloro‐di­chloro­tetrakis(N‐tri­methyl­ammonio‐p‐toluene­sulfonamidate‐κ²N,O)­tetramer­cury(II), [Hg{Me₃N(+)N(−)SO₂C₆H₄CH₃‐p}Cl₂]₄ or [Hg₄Cl₈(C₁₀H₁₆N₂O₂S)₄], four nearly linear and parallel Cl—Hg—Cl units associate through pairwise Hg⋯Cl interactions of 3.1–3.2 Å. Each Hg atom is also coordinated through N and O atoms to a yl­ide mol­ecule. The available structural data indicate that coordination of a sulfonyl‐stabilized nitro­gen yl­ide to a metal atom (Hg or Ag) has no detectable effect on its geometry.     

Improved Catalytic Performance of Pt Supported on Multi‐Wall Carbon Nanotubes as Cathode for Direct Methanol Fuel Cell Applications Prepared by Dual‐Stepped Surface Thiolation Processes

This study develops a simple surface modification process for modifying the MWCNT surface by thiolation reaction after the conventional nitric acid treatment for strong interface attachment of Pt NPs and improved dispersion onto MWCNTs. The thiolated MWCNTs (Pt/MWCNTs) showed significant improvement of methanol electro‐oxidation activity compared with that treated only by nitric acid solution. The prepared electrode with thiolated MWCNTs was used as the cathode for assembling MEA for DMFC single‐cell applications. Testing results indicate that the thiolated MWCNT cathode can improve the power density of MEA by more than 300% (from 4.6 to 20.6 mW cm^?2) compared with that treated only by conventional nitric acid reactions. The dual‐step modification process for MWCNT surface treatment showed significant improvement over the convention nitric acid treatment and can be successfully used in DMFC applications.     

Iterative Regularization Methods for the Multiple-Sets Split Feasibility Problem in Hilbert Spaces

In this paper, we introduce iterative regularization methods for solving the multiple-sets split feasibility problem, that is to find a point closest to a family of closed convex subsets in one space such that its image under a bounded linear mapping will be closest to another family of closed convex subsets in the image space. We consider the cases, when the families are either finite or infinite. We also give two numerical examples for illustrating our main method.

     

Asymptotic silence of generic cosmological singularities

In this Letter we investigate the nature of generic cosmological singularities using the framework developed by Uggla et al. We study the past asymptotic dynamics of general vacuum G2 cosmologies, which are expected to capture the singular behavior of generic cosmologies with no symmetries at all. Our results indicate that asymptotic silence holds, i.e., particle horizons along all time lines shrink to zero for generic solutions. Moreover, we provide evidence that spatial derivatives become dynamically insignificant along generic time lines, and that the evolution into the past along such time lines is governed by an asymptotic dynamical system which is associated with an invariant set-the silent boundary. We identify an attracting subset on the silent boundary that organizes the oscillatory dynamics of generic time lines in the singular regime. Finally, we discuss the dynamics associated with recurring spike formation.