Measurement of K β K /α values using proton beamvalues using proton beam

The Measurement of K _β K _/α intensity ratios are measured in some 3d shell elements by using a 2 MeV proton beam along with a high resolution Si(Li) detector. The present Measurement of K _β K _/α intensity ratios are in good agreement with Scofield modified theoretical values, thus supporting the basic assumptions in that theory. From the present Measurement of K _β K _/α intensity ratios, it is evident that due to chemical effects, the experimental Measurement of K _β K _/α intensity ratios will be increased while they will be decreased due to the presence of simultaneous M-shell vacancies which are produced due to proton excitation.     

A simple approach for synthesis of TiO2 nanotubes with through‐hole morphology

The present work reports a simple approach for fabrication of self‐standing titania (TiO₂) nanotube membranes with through‐hole morphology. The method is hydrofluoric acid free and the pore opening of TiO₂ nanotubes is performed by electrochemical thinning of the oxide barrier layer. A reduction of anodization voltage was applied at the end of the anodization process to cause a successful removal of the remaining barrier layer from the TiO₂ nanotubes during their detachment from the underlying titanium substrate. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Singularity-free dark energy star

We propose a model for an anisotropic dark energy star where we assume that the radial pressure exerted on the system due to the presence of dark energy is proportional to the isotropic perfect fluid matter density. We discuss various physical features of our model and show that the model satisfies all the regularity conditions and is stable as well as singularity-free.     

An in-plane insensitive multiaperture speckle shear interferometer for slope measurement

A modified two-aperture speckle shear interferometer that eliminates the contribution of the in-plane component and its derivative to the phase change, and yields a fringe pattern corresponding to the first-order partial derivatives of the out-of-plane displacement component, is reported in this note. In this method, two laterally sheared object points are viewed axially. The wave fields from these points are independently combined at the image plane of the imaging system.     

Precise measurement of hyperfine structure in the state of Rb

We demonstrate a technique to measure hyperfine structure using a frequency-stabilized diode laser and an acousto-optic modulator locked to the frequency difference between two hyperfine peaks. We use this technique to measure hyperfine intervals in the 5 P _3/2 state of ⁸⁵Rb and obtain a precision of 20 kHz. We extract values for the magnetic-dipole coupling constant A = 25.038(5) MHz and the electric-quadrupole coupling constant B = 26.011(22) MHz. These values are a significant improvement over previous results. Received 6 March 2003 Published online 15 April 2003     

Two-point time-series measurements of minor-species concentrations in a turbulent nonpremixed flame

We report a technique that is capable of making simultaneous two-point time-series measurements of minor-species concentrations in turbulent flames. The experimental setup, which incorporates picosecond time-resolved laser-induced fluorescence, has a spatial resolution of less than 250 microm and a temporal resolution of less than 100 micros, which spatially and temporally resolve microscales in many turbulent flows. Two-point time-series data are given for a standard turbulent nonpremixed flame at Re= 10,000, including a discussion of potential implications.     

Sonochemistry of volatile and non-volatile solutes in aqueous solutions: e.p.r. and spin trapping studies

Recent spin trapping studies of the free radical intermediates generated by the sonolysis of aqueous solutions are reviewed. Studies of rare gas saturated solutions of volatile solutes (e.g., methanol and ethanol) and of non-volatile solutes (acetate, amino acids, sugars, pyrimidines, nucleotides and surfactants) are consistent with the theory of three reaction zones in aqueous sonochemistry. The very high temperatures and pressures induced by acoustic cavitation in collapsing gas bubbles in aqueous solutions lead to the thermal dissociation of water vapour into hydrogen atoms and hydroxyl radicals. Reactions take place in the gas phase (pyrolysis reactions), in the region of the gas-liquid interface, and in the bulk of the solution at ambient temperature (similar to radiation chemistry reactions). By use of the rare gases with different thermal conductivities, the contributions of individual reaction steps with widely different energies of activation can be evaluated.