Additive influence on Cu nanotube electrodeposition in anodised aluminium oxide templates

Anodised aluminium oxide (AAO) templates have been utilised to investigate Cu deposition from a typical sulphate plating bath. The influence of the common additives poly ethylene glycol (PEG), chloride ion (Cl^?) and Bis-(sodium sulphopropyl)-disulphide (SPS) on the deposition process has been analysed. The growth of Cu wires or nanotubes (with tube walls of 40–70 nm) is significantly influenced by the action of the additives. In the presence of either Cl^? or SPS solid wire growth is observed, however, when PEG is added with Cl^? the growth of ordered Cu nanotubes is observed. SPS added to a bath containing Cl^? and PEG restores the growth of wires.     

How happy is your web browsing? A model to quantify satisfaction of an Internet user searching for desired information

We feel happy when web browsing operations provide us with necessary information; otherwise, we feel bitter. How to measure this happiness (or bitterness)? How does the profile of happiness grow and decay during the course of web browsing? We propose a probabilistic framework that models the evolution of user satisfaction, on top of his/her continuous frustration at not finding the required information. It is found that the cumulative satisfaction profile of a web-searching individual can be modeled effectively as the sum of a random number of random terms, where each term is a mutually independent random variable, originating from ‘memoryless’ Poisson flow. Evolution of satisfaction over the entire time interval of a user’s browsing was modeled using auto-correlation analysis. A utilitarian marker, a magnitude of greater than unity of which describes happy web-searching operations, and an empirical limit that connects user’s satisfaction with his frustration level—are proposed too. The presence of pertinent information in the very first page of a website and magnitude of the decay parameter of user satisfaction (frustration, irritation etc.) are found to be two key aspects that dominate the web user’s psychology. The proposed model employed different combinations of decay parameter, searching time and number of helpful websites. The obtained results are found to match the results from three real-life case studies.     

New precision mass measurements of neutron-rich calcium and potassium isotopes and three-nucleon forces

We present precision Penning trap mass measurements of neutron-rich calcium and potassium isotopes in the vicinity of neutron number N=32. Using the TITAN system, the mass of ^{51}K was measured for the first time, and the precision of the ^{51,52}Ca mass values were improved significantly. The new mass values show a dramatic increase of the binding energy compared to those reported in the atomic mass evaluation. In particular, ^{52}Ca is more bound by 1.74?MeV, and the behavior with neutron number deviates substantially from the tabulated values. An increased binding was predicted recently based on calculations that include three-nucleon (3N) forces. We present a comparison to improved calculations, which agree remarkably with the evolution of masses with neutron number, making neutron-rich calcium isotopes an exciting region to probe 3N forces.     

Germanium microsphere high-Q resonator

In this Letter, the fabrication and characterization of a microsphere resonator from the semiconductor germanium is demonstrated. Whispering gallery modes are excited in a 46 μm diameter germanium microsphere resonator using evanescent coupling from a tapered silica optical fiber with a waist diameter of 2 μm. Resonances with Q factors as high as 3.8×10(4) at wavelengths near 2 μm are observed. Because of their ultrahigh optical nonlinearities and extremely broad transparency window, germanium microsphere resonators offer the potential for optical processing devices, in particular at long wavelengths, such as around 2 μm.     

Generalized bi-Quasi-Variational Inequalities for Upper Hemi-Continuous Operators in non-Compact Settings

By using the concept of escaping sequences introduced by Border [2], existence theorems on generalized bi-quasi-variational inequalities for F-semi-monotone (re- spectively, bi-quasi-semi-monotone) operators are obtained in non-compact set- tings. As application, an existence theorem on generalized bi-complementarity problem for F-semi-monotone (respectively, bi-quasi-semi-monotone) operator is given in non-compact setting.     

Enantioselective synthesis of the antiinflammatory agent (-)-acanthoic acid.

An enantioselective synthesis of the potent antiinflammatory agent (-)-acanthoic acid (1) is described. The successful strategy departs from (-)-Wieland-Miescher ketone (10), which is readily available in both enantiomeric forms and constitutes the starting point toward a fully functionalized AB ring system of 1. Conditions were developed for a regioselective double alkylation at the C4 center of the A ring, which produced compound 32 as a single stereoisomer. Construction of the C ring of 1 was accomplished via a Diels-Alder reaction between sulfur-containing diene 43 and methacrolein (36), which after desulfurization and further functionalization yielded synthetic acanthoic acid. The described synthesis confirms the proposed stereochemistry of the natural product and represents a fully stereocontrolled entry into an underexplored class of biologically active diterpenes.     

Propagation of waves in a multicomponent plasma having charged dust particles

Propagation of both low and high frequency waves in a plasma consisting of electrons, ions, positrons and charged dust particles have been theoretically studied. The characteristics of dust acoustic wave propagating through the plasma has been analysed and the dispersion relation deduced is a generalization of that obtained by previous authors. It is found that nonlinear localization of high frequency electromagnetic field in such a plasma generates magnetic field. This magnetic field is seen to depend on the temperatures of electrons and positrons and also on their equilibrium density ratio. It is suggested that the present model would be applicable to find the magnetic field generation in space plasma.     

Hemi-Continuous Operators and Some Applications

Existence theorems of generalized variational inequalities and generalized complementarity problems are obtained in topological vector spaces for hemi-continuous (respectively, strong hemi-continuous) operators. Fixed point theorems are also given in Hilbert spaces for set-valued operators T which are upper semicontinuous such that I - T are hemi-continuous (respectively, strong hemi-continuous).     

Lie—Bäcklund Symmetries of Two-Dimensional SU(2) Yang—Mills System and Nonhomogeneous Lax Pair

We obtain the Lie—Bäcklund-type symmetries of the two-dimensional SU(2)Yang—Mills equation with the help of a generalized formal series method. Both(x, t)-dependent and independent symmetries are obtained and it is shown thatthey form a closed algebra. Finally a nonhomogeneous Lax equation is derivedusing these symmetries.     

Water diffusion in methacrylate based copolymer hydrogels of 2-hydroxyethyl methacrylate

The diffusion of water into cylinders of polyHEMA and copolymers of HEMA with THFMA, BMA and CHMA were studied over a range of copolymer compositions. The diffusion of water into the polymers was found to follow a Fickian, or case I mechanism. The diffusion coefficients of water were determined from mass measurements and NMR imaging studies. They were found to vary from 1.7 ± 0.2 x 10⁻¹¹ m² s⁻¹ for polyHEMA at 37°C to lower values for the copolymers. The mass of water absorbed at equilibrium relative to the mass of dry polymer varied from 52-58 wt% for polyHEMA to lower values for the copolymers.