Bulletin of the American Physical Society
Spring 2015 Meeting of the APS New England Section
Volume 60, Number 5
Friday–Saturday, April 24–25, 2015; Boston, Massachusetts
Session D1: Condensed Matter Physics |
Hide Abstracts |
Chair: Colin Howard, Boston University Room: Life Sciences and Engineering Building B01 |
Saturday, April 25, 2015 8:30AM - 8:42AM |
D1.00001: Gd (III) doped LiMn2O4 cathode material for lithium ion rechargeable batteries Rahul Singhal, Pura Ram, Rakesh Kumar Sharma The spinel structured LiMn$_{\mathrm{2-x}}$Gd$_{\mathrm{x}}$O$_{4}$ (x$=$0.01-0.05) have been synthesized via sol gel method. The physical and electrochemical characterization were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive x-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, Raman spectroscopy, cyclic voltammetry and charge-discharge studies. The reversibility of synthesized cathode was supported through cyclic voltammetry in 3.0 - 4.5 voltage range. The initial charge discharge capacity of cathode materials was found in range 130-140 mAhg$^{-1}$. The fabricated coin cell was tested up to 50 charge --discharge cycles with 0.5 C rate. The small amount of rare earth metal, Gd, doping showed improvement in capacity fading compared to LiMn$_{2}$O$_{4}$ cathode, offer its applicability for Li-ion rechargeable battery. [Preview Abstract] |
Saturday, April 25, 2015 8:42AM - 8:54AM |
D1.00002: Frequency Dependence of Dielectric Constant and Dielectric Loss in a-Se$_{90}$In$_{8}$Ag$_{2}$ CG glassy alloy Dipti Sharma, S.K. Sharma, R.K. Shukla, A. Kumar Amorphous chalcogenide glasses (CG) form the basis of re-writable CD and DVD solid-state memory technology. They exhibit thermally driven amorphous crystalline phase change which make them useful for encoding binary information on thin films of CGs and forms the basis of rewritable optical discs and non-volatile memory devices such as PRAM. CGs also show significant ionic transport that can be useful for data storage in a solid CG electrolyte. The present study shows the effect of frequency on dielectric parameters of an ionic CG of Se$_{90}$In$_{8}$Ag$_{2}$. They were measured in the frequency ranged from 200 Hz to 500 kHz and found to be decreased with frequency. The frequency dependence of dielectric loss can be explained in terms of Elliott's model of correlated barrier hopping over a potential barrier [1-3].\\[4pt] [1] D. Sharma et al., Thin Solid Films 357 (1999) 214-217;\\[0pt] [2] D. Sharma et al., Adv. Mater. Opt. Electron. 10 (2000) 251-259;\\[0pt] [3] D. Sharma et al., Materials and Manufacturing Process 18 (2003) 93-104 [Preview Abstract] |
Saturday, April 25, 2015 8:54AM - 9:06AM |
D1.00003: Quantum mechanical aspects of the decay of mechanical vibrations by electromagnetic radiation Allan Pierce A body undergoing mechanical vibrations loses energy by electromagnetic radiation. If the vibrations are of a thermal nature, and if the body is surrounded by a medium such as air at a lower temperature, then the loss of energy is adequately described by the theory of radiative heat transfer, but mechanical vibrations are generally not associated with thermal equilibrium. The present paper argues that any good approximate account of the physical mechanisms responsible for radiative decay of mechanical vibrations requires some, perhaps modest, understanding of quantum electrodynamics.The analysis begins with the simple example of a molecule in its first excited vibrational state, with the objective of predicting the relaxation time for the decay to the ground state. It is noted that the overall theoretical framework developed by Weisskopf and Wigner (1930) gives the same overall result as the correspondence principle theory advanced somewhat earlier by Slater (1925), and the author consequently seeks to develop a general approximate theory based on the correspondence principle. It is shown in particular that the reciprocal of the relaxation time is a dimensionless quantity times the cube of the fine structure constant times the frequency of the electromagnetic emission. [Preview Abstract] |
Saturday, April 25, 2015 9:06AM - 9:18AM |
D1.00004: The basic physical principles involved in the conversion of vibrational energy to electrical energy in off-shore ocean wave energy systems Amadou Thiam While details of the currently most publicized devices for ocean wave energy conversion to electrical energy are generally not disclosed in the open literature, the author believes that, for devices not on the coastline, the common transduction mechanism involves electromagnetic induction with conducting wires moving relative to permanent magnets. A general discussion is given of how such a mechanism can be used in this application. The overall analysis of the mechanical system with lumped or distributed masses and elastic elements driven by buoyancy forces associated with incident ocean waves is facilitated, if the transduction system is modeled as linear mechanical dashpots, and the procedures for deriving effective dashpot constants are described. The analysis suggests that, for waves in a general frequency range, there is an optimal choice for the parameters of the mechanical system, so that the maximum electrical power can be harvested. The optimal energy extracted per wave cycle is invariably much less than the total mechanical energy of the oscillating components of the system. A distinction is made between freely floating systems and systems anchored to the ocean bottom and between systems driven near a resonant frequency and those driven substantially below resonance. [Preview Abstract] |
Saturday, April 25, 2015 9:18AM - 9:30AM |
D1.00005: Low Temperature D.C. Electrical Transport in Nsutite Peter LeMaire, Jonathan Lembeck, John Distin This work attempts to shed some more light on earlier work in the naturally occurring manganese oxide Nsutite (Mn$^{4+}_{1-x}$Mn$^{2+}_x$O$_{2-2x}$(OH)$_{2x}$ where x = 0.06 - 0.07), that showed non-linear I-V response, and what seemed to be metallic to non-metallic behavior below 140 K. New data of four lead voltage measurements at constant current shows transient voltages below 140 K, and the results of the data analyzed to obtain the electronic conductivity data between 40 K and 140K. The significance of these measurements and results will be discussed. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700