This paper deals with the investigation of the reactions of aqueous molybdates in the presence of copper ions under varying pH to obtain new copper molybdates and rationalize the structures formed in terms of the self-assembling nano-building blocks of polyoxomolybdates (POMs). The reactions led to the precipitation of porous copper molybdates: 1D polymeric anions in (NH4)6[{Cu(H2O)4}{Mo36O112(H2O)16}].21H2O, 1, a 3D framework bimetallic oxide in Cu3Mo2O9, 2. Our results reported here clearly suggest that copper complexes formed during the initial stages of the reaction probably dictate the architecture of the final solids. Interestingly the magnetic properties studied on these compounds showed that 1 shows paramagnetic ordering since magnetically active centres i.e. Cu(II) are separated by large diamagnetic centres of {Mo36} cluster anions where as 2 shows the dominance of antiferromagnetic near-neighbor interaction.
Background/Objectives: The present research focuses on comparative studies of two different type of chaff fibres for their effectiveness as electronics counter measure. Chaffs are electronic counter measures used in creating false radar signature to deceive tracking radar systems. Many types of chaff payloads are there in use, but the major one is aluminium fibres. These chaffs are designed to cover radar frequency range from 2-18 GHz. However, in future, tracking radars will operate in higher frequency range and will have improved algorithms to mitigate chaff noise of certain Radar Cross Section (RCS) threshold. Methods: The researcher used two different chaff fibres and their corresponding RCS are measured in anechoic chamber for their comparative study. Findings: It is observed that the RCS of the copper coated carbon (CuC) fiber is nearly equal to that of aluminium fiber but due their thinner diameter packing density of chaff fibres within a specified chaff cartridge volume has increased thus resulting in more number of dipole per chaff payload. Larger number of dipoles will help in improving dynamic RCS of chaff payload as it is directly proportional to the number of dipoles. Moreover, the terminal velocity of copper coated carbon fibres is lesser than that of aluminium fibres has improved the persistent time for CuCfiberwhich is a desirable parameter for the effective performance of chaff payload. Novelty: In order to increase dynamic RCS threshold one needs to increase chaff fiber density and chaff cloud suspension time. Both these can be achieved by the development of innovative thin CuCchaff fibres. In this paper, RCS of light weight and thin copper coated carbon chaff fibres were studied in comparison with traditional aluminium fibres and their advantages over aluminium fibres are reported.
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