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Gloriosa superba L is an important medicinal plant and its seeds, tubers are used for medicine. To investigate the phyto-components of Gloriosa superba L collected from various habitats of Tamil Nadu state, India. In the present study, the phyto-components from the tubers of Gloriosa superba L cultivars from Sirumalai (GA1) Mulanoor (GA2), Thuraiyur (GA3), Konganapuram (GA4) and Vedaranyan (GA5) were extracted by ethanolic extract and the composition of chemicals and its concentration in the tubers were determined by Gas Chromatography – Mass spectrometry (GC-MS) analysis.Among the phyto-components GA1 shows 15 phyto-components, GA2 shows 13 phyto-components, GA3 shows that 8 phyto-components, GA4 shows 14 phyto-components and GA5 shows 13 phyto-components. GA1, GA2, GA4 and GA5 ecotypes possessed higher phyto-components. Colchichine is an important alkaloid of Gloriosa superba L was found in GA2, GA3, GA4 and GA5 accessions in good concentration. The results reveals that the geographical origin and climate condition of a accession causes polymorphisms in the accumulation of phyto-components, its composition and morphological traits in Gloriosa Superba L originating from different ecotypes of Tamil Nadu state.

Measurements have been made on various antenna configurations suitable for monolithic integration at millimeter-wave frequencies. The basic structure consists of a single slot dipole radiator etched on a dielectric substrate and combined with a beam lead detector diode. Enhancement of the antenna directivity has been achieved through the use of dielectric rods oriented over the slot area. Addition of these rods has improved directivity up to 10 dB at 60 GHz.

As part of a diode and mixer development effort,/sup 1/ a low cost subharmonically pumped millimeter-wave mixer design using GaAs beam lead diodes has been developed. It adopts a configuration which incorporates both waveguide and suspended stripline using a low cost Duroid substrate. A DSB noise figure of 8.5 dB has been achieved-using a 47 GHz Gunn local oscillator and 5- to 500-MHz IF amplifier with a 1.5-dB noise figure.

Gallium Arsenide Gunn diodes have been used to develop self-mixing oscillators in the 94 GHz region. Experiments have been performed to measure conversion loss, excess noise, minimum detectable signal and IF impedance. The results are compared with balanced mixers and video detectors to place the self-mixing oscillator in proper perspective in terms of performance.

FM transmitter oscillator of 400 mW output power at 60 GHz and 275 mW at 94 GHz using silicon double-drift IMPATT diodes and varactor-tuned local oscillators were developed for data transmission at 100 megabits/sec data rate.

A 60 GHz mixer compatible with beam lead diodes using a novel circuit configuration incorporating dielectric loaded waveguide, stripline and coaxial transmission lines has been designed and fabricated. The mixer was developed for low-cost, high volume applications.

The authors describe a high-performance, state-of-the-art antenna pattern measurement instrumentation system. The system utilizes advanced concepts to achieve high-accuracy, large-dynamic-range antenna pattern measurements at speeds more than 100 times faster than with any instrumentation system available today. Such speeds and range are especially required when measuring the pattern of millimeter-wave antennas. The basic system covers the frequency band 0.1 to 26.5 GHz and can be extended to cover full waveguide bands through 110 GHz. The system performs conventional measurements in the CW (continuous-wave) mode and can also operate in a pulse mode. The pulse mode of operation allows the operator to range gate out interfering multipath signals which often occur in practical ranges. This provides a measurement capability over a much larger dynamic range than can be achieved by a CW system alone or with extensive clutter subtraction routines or extensive usage of anechoic material. >

Point-to-point digital millimeter wave radios are being increasingly deployed because of the rapid expansion of commercial wireless services. Providers of wireless services continue to demand systems with higher data rates and higher carrier frequencies. The first valuable niche market, where millimeter radio fits in, is the backbone network at 23 GHz, 26 GHz, 38 GHz and 55 GHz for the 0.9 or 1.8 GHz GSM type cellular telephone network. Wireless broadband networks at 28 GHz and 42 GHz is the second valuable niche market for millimeter wave radios. For an example, a total requirement of 16,000 38 GHz radios is estimated to be necessary for the German DCS 1800 mobile telephone network, Eplus, at the end of the installation in 1998.

Millimeter-wave boron-nitride image-guide integrated passive devices such as couplers, detectors, and balanced mixers have been developed with performances comparable to their metal waveguide circuit counterparts.

A cost effective scheme of fabricating millimeter-wave passive components in dielectric waveguide has been conceived and a computer program has been written for analyzing their frequency responses. By inlaying Teflon guides in the properly designed contours cut in a low dielectric constant foam material, passive components such as quadrature hybrids, in-phase power dividers, and six-port network analyzers have been developed. Design and performance data are presented.

Supersonic stellar winds are quite common among the brightest and/or the youngest stars, i.e., O stars and B supergiants, T Tauri stars, Herbig-Haro objects etc. We propose that the shocked region at the boundary between the stellar wind and the surrounding medium is, under certain conditions, the site of acceleration of charged particles with a power-law energy spectrum, extending a suggestion proposed by Jokipii for the solar wind. This mechanism should operate up to approx.10/sup 15/ eV. On the basis of the Copernicus UV observations, we suggest that the luminous OB stars pertaining to the Gould Belt are the major sources of local cosmic rays. We present observational support to cosmic-ray acceleration by stellar wind in the rho Oph cloud, based on high-energy ..gamma..-ray observations performed by the COS B satellite. A major consequence of these views is the peculiar character of our local galactic environment as far as cosmic rays are concerned.

Gamma-ray intensity and interstellar absorption derived from galaxy counts are used to explore the local interstellar medium. It is pointed out that both are valuable tracers of column density of the total gas: ..gamma..-rays as they relate to interaction between high-energy particles and interstellar gas in all its forms, interstellar absorption in the context of the gas-to-dust relationship. Large scale features of the local interstellar medium are revealed, in particular a wide concentration of nearby molecular gas in the Aquila-Ophiuchus-Sagittarius region. The overall relation between gas and ..gamma..-radiation is used to derive quantitative estimates of the cosmic-ray electron flux and spectrum below 1 GeV.