Nitrogenated and hydrogenated amorphous carbon (a-C:H:N) films have been deposited by a plasma beam source using a gas mixture of C2H2 , Ar and N2 . The Ar/C2H2 ratio is kept constant at a ratio of 3, with the nitrogen flow allowed to vary. Nonnitrogenated films, with Ar/C2H2 ratios of 3 and 6 were also deposited and analyzed before attempting to identify the modifications to the microstructura...

An efficient technique for calibrating video cameras to record optical density (OD) from microscopic images is described. The method corrects for variation over the field of the brightfield and darkfield intensities, does not assume a linear response of the camera to the incident intensity and requires a single calibration filter.

Interpretation of the Raman optical activity (ROA) of peptides is difficult because of molecular flexibility and interaction with the solvent. Typically, simulations and experiments are compared in terms of a qualitative agreement between the spectra. However, on a series of the Pro-Gly, Gly-Pro, Pro-Ala, and Ala-Pro dipeptides more precise conformer ratios could be obtained with the aid of the...

A digital decision-directed phase-locked loop (PLL) for use in optical pulse code-division multiple-access (CDMA) systems based on coherent correlation demodulation is proposed. PLL performance is affected by multiuser interference, laser phase noise and optical shot noise. The effect of these sources of interference and noise on PLL performance is evaluated based on a nonlinear model (the Fokk...

in this paper, the effects of reflected waves of the facets on the internal optical intensity of semiconductor dfb lasers are investigated. the uniformity of optical intensity along the cavity length is evaluated with flatness parameter. the dependence of this parameter on coupling coefficient, reflectivity and grating phase at the facets is also studied. this investigation shows that in some s...

A CH3F:O2 (50%:50%) inductively coupled discharge, sustained in a compact plasma reactor, was investigated as a function of power (20–400 W) and pressure (9–30 mTorr), using optical emission spectroscopy and Langmuir probe measurements. The electron density increased linearly with power but only weakly with pressure. The effective electron temperature was nearly independent of power and pressur...

Optical imaging in a highly scattering medium is effective only at very shallow depths which limits its use as a diagnostic tool in biomedical imaging, particularly for tumor detection. By combining optical and acoustic modalities, high-contrast, tumor state-relevant optical information at higher spatial resolutions can be achieved. Hybrid imaging modalities such as acousto-optic and photoacous...

BACKGROUND AND OBJECTIVES A single reactive IgG anti-Dengue virus ELISA test in the absence of IgM antibodies or NS1 antigen may denote current infection or past exposure to the virus. To determine whether IgG index value can be used to identify true current dengue infection we conducted a prospective observational study. MATERIALS AND METHODS Suspected dengue patients (n =1745) were tested i...