Cochin University of Science and Technology

About: Cochin University of Science and Technology is a education organization based out in Kochi, Kerala, India. It is known for research contribution in the topics: Thin film & Natural rubber. The organization has 5382 authors who have published 7690 publications receiving 103827 citations. The organization is also known as: CUSAT & Cochin University.

Zeolite-encapsulated Co(II), Ni(II) and Cu(II) complexes as catalysts for partial oxidation of benzyl alcohol and ethylbenzene

Abstract: Co(II), Ni(II) and Cu(II) complexes of dimethylglyoxime and N,N � -ethylenebis(7-methylsalicylideneamine) have been synthesized in situ in Y zeolite by the reaction of ion-exchanged metal ions with the flexible ligand molecules that had diffused into the cavities. The hybrid materials obtained have been characterized by elemental analysis, SEM, XRD, surface area, pore volume, magnetic moment, FTIR, UV-Vis and EPR techniques. Analysis of data indicates the formation of complexes in the pores without affecting the zeolite framework structure, the absence of any extraneous species and the geometry of encapsulated complexes. The catalytic activities for hydrogen peroxide decomposition and oxidation of benzyl alcohol and ethylbenzene of zeolite complexes are reported. Zeolite Cu(II) complexes were found to be more active than the corresponding Co(II) and Ni(II) complexes for oxidation reactions. The catalytic properties of the complexes are influenced by their geometry and by the steric environment of the active sites. Zeolite complexes are stable enough to be reused and are suitable to be utilized as partial oxidation catalysts. © 2003 Published by Elsevier B.V.

Effect of doping on the dielectric properties of cerium oxide in the microwave and far-infrared frequency range

Abstract: Cerium oxide (CeO 2 ) has been prepared as a ceramic dielectric resonator by a conventional solid-state ceramic route. The sintered CeO 2 has a high dielectric quality factor (Q×f), Q value of 10 000 at 6 GHz with a relative permittivity (e') of 23, and temperature coefficient of resonant frequency (τ r ) of -53 ppm/°C. The Q value increases to 20 000 at 6 GHz when the CeO 2 is doped with 1 mol% CaCO 3 . Higher levels of CaCO 3 doping lowers the Q and e' values and simultaneously decreases τ f . TiO 2 doping decreases τ f and slightly increases e', but deceases the Q value. The Q value of pure CeO 2 increases to 105 000 at a frequency of 5.58 GHz when it is cooled to 30 K, whereas Q 85 000 at 5.48 GHz for 1-mol%-CaCO 3 -doped CeO 2 at 30 K.

A Compact Quad Element Slotted Ground Wideband Antenna for MIMO Applications

Abstract: A compact planar quad element wideband antenna for multiple-input-multiple-output (MIMO) system is proposed in this communication. A single element consists of a partially grounded printed monopole antenna loaded with a split ring resonator. The bandwidth of the antenna is from 2.2 to 6.28 GHz (96.2%), which covers LTE (2.2–3.8 GHz), Bluetooth (2.4 GHz), WLAN (2.4 and 5.1–5.8 GHz), WiMAX (2.3–5.7 GHz), and ISM bands (2.4/5.2/5.8 GHz). The fabricated antenna has an isolation greater than 14 dB between its elements, with a peak gain of 4 dBi and a peak efficiency of 91%. Polarization diversity is employed to accommodate four elements in an FR4 substrate, with an overall dimension of $0.33\lambda \times 0.33\lambda \times 0.01\lambda $ . The antenna has a simple planar design which is easy to fabricate with no intricate process involved.