“Design and Development of Coplanar Strip Fed Planar Antennas”

With the recent progress and rapid increase in the field of communication, the designs of antennas for small mobile terminals with enhanced radiation characteristics are acquiring great importance. Compactness, efficiency, high data rate capacity etc. are the major criteria for the new generation antennas. The challenging task of the microwave scientists and engineers is to design a compact printed radiating structure having broadband behavior along with good efficiency and enhanced gain. Printed antenna technology has received popularity among antenna scientists after the introduction of planar transmission lines in mid-seventies. When we view the antenna through a transmission line concept, the mechanism behind any electromagnetic radiator is quite simple and interesting. Any electromagnetic system with a discontinuity is radiating electromagnetic energy. The size, shape and orientation of the discontinuities control the radiation characteristics of the system such as radiation pattern, gain, polarization etc. It can be either resonant or non-resonant. This thesis deals with antennas that are developed from a class of transmission lines known as coplanar strip-CPS, a planar analogy of parallel pair transmission line. The specialty of CPS is its symmetric structure compared to other transmission lines, which makes the antenna structures developed from CPS quite simple for design and fabrication. The structural modifications on either metallic strip of CPS results in different antennas. The first part of the thesis discusses a single band and dual band design derived from open ended slot lines which are very much suitable for 2.4 and 5.2 GHz WLAN applications. The second section of the study is vectored into the development of enhanced gain dipoles. A single band dipole and a wide band enhanced gain dipole suitable for 5.2/5.8 GHZ band and imaging applications are developed and discussed. Last part of the thesis discusses the development of directional UWBs. Three different types of ultra-compact UWBs are developed and almost all the frequency domain and time domain analysis of the structures are discussed.

Immobilization of Diastase α-amylase on to synthetic and natural polymers

Several natural and synthetic supports have been assessed for their efficiency for enzyme immobilization. Synthetic polymer materials are prepared by chemical polymerization using various monomers. As a kind of important carrier, synthetic polymer materials exhibit the advantages of good mechanical rigidity, high specific surface area, inertness to microbial attack, easy to change their surface characteristics, and their potential for bringing specific functional group according to actual needs. Hence, they have been widely investigated and used for enzyme immobilization. When it comes to the natural polymer materials, much attention has been paid to cellulose and other natural polymer materials owing to their wide range of sources, easy modification, nontoxic, and pollution-free, with a possibility of introducing wide variety of functional groups and good biocompatible properties. In this work report the use of synthetic polymer, polypyrrole and its derivatives and natural polymers coconut fiber and sugarcane bagasse as supports for Diastase α- amylase immobilization. An attempt was also made to functionalize both synthetic and natural polymers using Amino-propyl triethoxysilane. Supports and their immobilized forms were characterized via FT-IR, TG, SEM, XRD, BET and EDS techniques. Immobilization parameters were also optimized so as to prepare stable immobilized biocatalyst for starch hydrolysis.

Novel [3+2] annulation reaction of nitrones with Burgess reagent and a few related reactions

Burgess reagent first prepared by E. M. Burgess in 1968, is a mild and selective dehydrating agent for secondary and tertiary alcohols and due to the amphipolar nature it is gainfully employed in a number of creative synthetic ventures. A close examination of the structure of Burgess reagent reveals that it can act as a 1,2-dipole. To the best of our knowledge, no attempts have been made to tap full synthetic potential of the amphipolar nature of this reagent and no reports on 1,3-dipolar addition to a σ-bond in acyclic systems are available in literature. In this context, we propose to unravel novel applications of Burgess reagent based on its amphipolar nature. Rich and multifaceted chemistry of nitrones form the basis of many successful chemical transformations used in attractive synthetic strategies. For the last 50 years special attention has been given to nitrones due to their successful application as building blocks in the synthesis of various natural and biologically active compounds. Our interest in nitrones stems out of its unique character: i.e. it is a 1,3-dipole exhibiting distinct nucleophilic activity. We reasoned that 1,3-dipole possessing significant nucleophilicity should react with amphipolar Burgess reagent with elimination of triethylamine to give the corresponding five-membered ring product by formal dipolar addition to a σ bond. To test this hypothesis we studied the reaction of nitrones with Burgess reagent. This thesis reveals our attempts to explore the [3+2] annulation reaction of nitrones with Burgess reagent which was found to be followed by a rearrangementinvolving C-to-N aryl migration, ultimately resulting in diarylamines and carbamates. We have also examined the reaction of cyanuric chloride with nitrones in DMF with a view to exploit the nucleophilicty of nitrones and to unravel the migratory aptitude, if any, observed in this reaction

DINKAH KA GADHYA SAHITHYA-EK ADHYAYAN

HINDI

A STUDY OF THE SHORT STORIES OF WOMEN WRITERS IN HINDI BEFORE INDEPENDENCE

hindi

THE NOVELS AND SHORT STORIES OF AJNEYA [A STUDY]

Hindi

Sumitranandan ki kavitha-ek adhyan

Hindi

ADHUNIK HINDI NATAKOM KI PRAMUKH PRAVRITTIYAN-EK ADHYAYAN (1950 . 1975)

Hindi

Love and Beauty in the Romantic Poetry of Hindi and Malayalam

Hindi

NEW HINDI POETRY AN AESTHETIC STUDY

HINDI

A STUDY or THE FICTION or BHISHAM SAHNI

HINDI

CONCEPT OF POETRY IN THE WORKS OF MODERN HINDI POETS

HINDI

POETICAL WORKS OF KEDARNATH AGARWAE. —A CRITICAL STUDY

HINDI

THE PDETICAL WORKS DF GIRI-IA KUMAR MATHUR: SENSIBILITY AND TECHNIQUE

HINDI

SAMAJIK MOOLYOM KA SWAROOP ASK KE IIPIIYASOM MEIN

HINDI