Showing papers by "Techno India published in 1996"

Novel single-resistance-controlled-oscillator configuration using current feedback amplifiers

Abstract: A novel configuration is presented which can realize single-resistance controlled active-RC and active-R oscillators and low-pass/band-pass filters from the same structure.

On the design of linear phase, FIR integrators for midband frequencies

Abstract: The ideal frequency responses: 1/(j/spl omega/) (an integrator) and 1//spl omega/ (an integrating Hilbert transformer) are usually approximated by IIR structures. This paper suggests their FIR approximations. Maximal flatness at /spl omega/=/spl pi//2 yields exact mathematical formulas for computing the weights. The proposed designs are particularly suitable for the frequency range: 0.1/spl pi//spl les//spl omega//spl les/0.90/spl pi/.

Mathematical morphological operations of boundary-represented geometric objects

Abstract: The resemblance between the integer number system with multiplication and division and the system of convex objects with Minkowski addition and decomposition is really striking. The resemblance also indicates a computational technique which unifies the two Minkowski operations as a single operation. To view multiplication and division as a single operation, it became necessary to extend the integer number system to the rational number system. The unification of the two Minkowski operations also requires that the ordinary convex object domain must be appended by a notion of inverse objects or negative objects. More interestingly, the concept of negative objects permits further unification. A nonconvex object may be viewed as a mixture of ordinary convex object and negative object, and thereby, makes it possible to adopt exactly the same computational technique for convex as well as nonconvex objects. The unified technique, we show, can be easily understood and implemented if the input polygons and polyhedra are represented by their slope diagram representations.

Diffuse ferroelectric transition and relaxational dipolar freezing in ?: III. Role of order parameter fluctuations

Abstract: Results of a high-temperature x-ray powder diffraction study of the phase transition between cubic and tetragonal phases of are presented for x = 0.08 and 0.12 which exhibit sharp and diffuse dielectric anomalies, respectively. Experimental evidence and arguments are advanced to show that the cubic and tetragonal phases coexist over a wide range of temperatures and that this coexistence is due to the fluctuation of the order parameter which is coupled electrostrictively to strains. For x = 0.08, the phase coexistence disappears below the dielectric anomaly temperature , indicating the critical nature of the fluctuations. For x = 0.12, these fluctuations are non-critical since the phase coexistence persists even below . The complete conversion to the tetragonal phase occurs at which is nearly lower than ). It is shown that the spontaneous polarization also increases gradually below and levels off at . The existence of structural and polarization anomalies well below the frequency-independent dielectric anomaly temperature cannot be rationalized either in terms of the Landau-like theories for ferroelectric transitions which predict or in terms of dipole glass transitions and/or relaxor ferroelectric transitions for which should be frequency dependent.

On a mixed-hybrid finite element method for anisotropic plate bending problems

Abstract: The paper deals with a new mixed-hybrid finite element method for anisotropic elastic plate bending problems, which gives a simultaneous approximation to bending and twisting moment tensor and deflection fields in the interior of each triangle and traces of the displacement field and its normal derivative on sides of each triangle. Efficient computer implementation procedures for this mixed-hybrid scheme have been developed. Results of numerical experiments on different anisotropic plates of practical and research interest are given.

The indecomposability problem in binary morphology: an algorithmic approach

Abstract: An indecomposable shape is like a prime number. It cannot be decomposed further as a Minkowski sum of two simpler shapes. With respect to Minkowski addition (dilation), therefore, the indecomposable shapes are the fundamental building blocks of all geometric shapes. However, just as it is difficult to identify whether a given number is a prime number or not, it is equally or more difficult to say whether a given shape is indecomposable or not. In this paper we take up a subdomain of binary images, called the weakly taxicab convex image domain, and show how the indecomposability problem in that shape domain can be approached in a manner closely analogous to the number theoretic way. Apart from our attempt to show that the indecomposability problem is an extremely interesting mathematical problem, our algorithmic treatment of the problem also leads to an efficient method of computing Minkowski addition and decomposition of binary images.

Double resonance measurements of far-infrared lasing transitions in methanol

Abstract: In this work, precise frequencies were measured for two important far IR (FIR) laser transitions in methanol optically pumped by the 9P(16) CO 2 laser line at an offset of +64 MHz from the line center, using IR - millimeter wave double resonance technique. The two measured FIR frequencies are at 525,427.902 and 477,790.879 MHz, with an estimated precision of +/- kHz. In addition another frequency was measured at 573,025.151 MHz, and this line corresponds to an absorption transition whose lower level is the upper pumped level. The measurements provide valuable confirmation for the assignments of the IR as well as the FIR transitions. In addition, we also measured accurate frequencies for several transitions in the ground vibrational state in the range 109-127 GHz.

Autofluorescence from tissue as a marker for carcinoma

Abstract: Cancer is a disease whose cause has been eluding researchers. This paper details a new method for the diagnosis of cancer using characteristic autofluorescence from tissues. The experiments were carried out using a nitrogen laser, spectrofluorometer and tissue samples of normal and cancer tissues. The fluorescence spectra of various samples were obtained and observed both by in-vivo and in-vitro studies. Results from these studies have been detailed. The paper also presents a hypothesis on the origin of cancer.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.