The transmission properties of optical waveguides in SIMOX structures

The numerical aperture of step index planar waveguides in SIMOX structures is 3.16. Analysis suggests that some of the higher-order modes that are supported by the waveguide will be reflected at the output face, due to total internal reflection. This situation therefore suggests that the propagation losses of such waveguide structures may be lower than those measured by conventional methods.     

Broadband emission spectrum of a continuous plasma jet in a mixture of noble gases with SF6 molecules

A broad band in the visible emission spectrum of a continuous Ar/Kr/SF₆ plasma jet is detected at a distance l>75 mm from the plasmatron nozzle. Experimental dependences of the maximum emission intensity on the parameters of the plasma source are presented.     

Optical characteristics of laser-produced antimony plasma

The processes occurring in expanding laser-produced antimony plasma are investigated by the emission spectroscopy method. The plasma expansion velocity, the recombination time of SbII, and the electron temperature and density are determined from the dynamics of SbI line emission. Based on the results obtained, the processes occurring during the formation and expansion of laser-produced antimony plasma are qualitatively analyzed.     

Smoothing minimally supported frequency wavelets: Part II

The main purpose of this paper is to give a procedure to “mollify” the low-pass filters of a large number ofMinimally Supported Frequency (MSF) wavelets so that the smoother functions obtained in this way are also low-pass filters for an MRA. Hence, we are able to approximate (in the L ² -norm) MSF wavelets by wavelets with any desired degree of smoothness on the Fourier transform side. Although the MSF wavelets we consider are bandlimited, this may not be true for their smooth approximations. This phenomena is related to the invariant cycles under the transformation x ↦2x (mod2π). We also give a characterization of all low-pass filters for MSF wavelets. Throughout the paper new and interesting examples of wavelets are described.     

Thermotropic liquid-crystalline behaviour from mixtures of non-mesogenic molecules

A class of non-mesogenic molecules, which as mixtures exhibit monotropic nematic phases, is described.     

Average speaking fundamental frequency in soprano singers with and without symptoms of vocal attrition

Nineteen trained soprano singers aged 18–30 years vocalized tasks designed to assess average speaking fundamental frequency (SFF) during spontaneous speaking and reading. Vocal range and perceptual characteristics while singing with low intensity and high frequency were also assessed, and subjects completed a survey of vocal habits/symptoms. Recorded signals were digitized prior to being analyzed for SFF using the Kay Computerized Speech Lab program. Subjects were assigned to a normal voice or impaired voice group based on ratings of perceptual tasks and survey results. Data analysis showed group differences in mean SFF, no differences in vocal range, higher mean SFF values for reading than speaking, and 58% ability to perceive speaking in low pitch. The role of speaking in too low pitch as causal for vocal symptoms and need for voice classification differentiation in vocal performance studies are discussed.