Polyacrylonitrile (PAN)-based electrolytes have been prepared by encapsulating Li salt solutions obtained by dissolving LiN(SO 2 CF 3 ) 2 , LiAsF 6 , LiSO 3 CF 3 , or LiPF 6 in a plasticizer mixture of ethylene carbonate (EC) and propylene carbonate (PC). The conductivity of these electrolytes is governed by a combination of factors including the relative amounts of PAN, EC, PC and the Li salt, and temperature. A conductivity of about 4.5 × 10 -3 Ω -1 cm -1 at 30°C was exhibited by EC-rich electrolytes containing both LiN(SO 2 CF 3 ) 2 and LiPF 6 . The cationic transference numbers, measured using a dc polarization method coupled with impedance spectroscopy, were found to be between 0.2 and 0.3 for electrolytes containing LiN(CF 3 SO 2 ) 2 and LiPF 6 . The tensile strength of the electrolytes was observed to increase from 60 to 140 lb/in. 2 upon incorporation of the thermally activated cross-linking agent ethylene glycol dimethacrylate. Cyclic voltammetry on Pt electrodes has shown that these electrolytes have an inherent oxidation stability window extending up to about 5 V versus Li + /Li. On Al, Ni, and Cu electrodes, however, oxidation was observed at lower potentials because of metal corrosion reactions. Copper was reversibly oxidized at 3.5 V, irrespective of the Li salt present in the electrolyte. On the other hand, the nature of the Li salt influenced the corrosion potentials of Al and Ni. Nickel was found to be stable up to 4.2 V in the presence of LiAsF 6 , whereas it was oxidized at about 3.5 and 4 V when the electrolyte contained LiN(SO 2 CF 3 ) 2 and LiSO 3 CF 3 , respectively. Aluminum electrodes showed no oxidation currents up to 4.2 V when the salts were LiPF 6 and LiAsF 6 which contrasted the behavior with LiN(SO 2 CF 3 ) 2 and LiSO 3 CF 3 showing oxidation at e4 V. The electrochemical stability of the electrolytes was further verified in Li/LiMn 2 O 4 cells.

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A quick and efficient computer program was developed in order to resolve the peaks from the thermoluminescence (TL) glow curve. The program was designed to be easily used on any MS Windows-based computer with a graphical user interface. In this program, a new method based on the general one-trap TL equation was adopted to analyse the TL glow curve with the traditional first-order, second-order and general-order kinetics model. The method described here, general approximation, generates TL glow peaks and interpolates the relevant TL parameters from the glow data. The program was tested with simulated and experimental TL glow data and the results were found to be adequate and reliable.

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Dosimetric characteristics of LiF:Mg,Cu,Si thermoluminescent (TL) material developed at KAERI have been investigated and compared with those of commercially available LiF:Mg,Cu,P (GR-200A). LiF:Mg,Cu,Si thermoluminescence dosimeter (TLD) can be heated up to 573K without any loss of TL sensitivity or any change in the glow curve structure. High-temperature glow peak in LiF:Mg,Cu,Si is significantly lower than that in GR-200A, consequently the residual signal is only 0.025%, which is about 35 times less than that of GR-200A. The TL sensitivity of the LiF:Mg,Cu,Si TLD is about 55 and 1.1 times higher than those of the LiF:Mg,Ti (TLD-100) and GR-200A, respectively.

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We investigated the effects of surface roughness and grain boundary diffusion (GBD) at elevated temperatures on the Auger-electron-spectroscopy sputter depth profiles of Co–Ag bilayers and the GBD process of Ag atoms in Co. The Ag layer in the Ag/Co bilayer is transformed from a uniform layer to discrete islands by heat treatment. Enhanced mobility during sputtering at elevated temperatures makes Ag atoms migrate continually from islands to cover neighboring exposed Co, which reduces the size of Ag islands. On the other hand, the surface morphological modification of Co/Ag bilayer does not occur by heat treatment, and the depth profile at 340 °C resembles that from a uniformly intermixed film, which shows a drastic difference from that of Ag/Co. This is explained with a very thin and stable accumulation of Ag on the Co layer by GBD. A model of structural changes in Co/Ag subjected to ion sputtering at elevated temperatures is proposed on the basis of the results. The activation energy and pre-exponential factor for GBD of Ag in Co are found to be 0.46±0.06 eV and ∼1×10−8 cm2/s, respectively.

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