http://www.researchonline.mq.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:13867 4 page(s) 2011-06-29T06:21:05.843Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:13869 The gold(110) single crystal exhibits a (1 × 2) surface structure when clean, but when immersed in 0.01 M HClO4 under potential control the structure has been found to change. Throughout the double-layer region the structure remains as (1 × 2) but when the potential is increased above 0.9–1.0 V vs. Ag/AgCl (the pre-oxidation region) the surface structure changes to a centred rectangular structure. This structure forms reproducibly but has limited stability. After the initial oxidation, the structure prevails until 1.2–1.3 V, whereupon oxidation occurs on a larger scale and the surface structure becomes (1 × 1). These structures return to (1 × 2) after reduction of the oxide, proving that the structural changes are reversible. X-ray photoelectron spectroscopy of these regions has shown a difference in the chemical state of the oxygen. Adsorbed perchlorate ion is initially the only oxygen component but as the potential increases the peak shifts into the hydroxide region and finally splits into a hydroxide peak and a metal oxide peak. This study indicates a new way of looking at the structure and composition of the gold surface and provides insight into the nature of the interaction between the surface and the solution. 2011-06-29T06:21:01.132Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:13870 9 page(s) 2011-06-29T06:20:59.695Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:13873 A comparative study of the cathodic behavior of electrolytic manganese dioxide (EMD) and chemically prepared battery grade manganese dioxide (BGM) in Zn|MnO₂|aqueous lithium hydroxide (LiOH) cells has been carried out. The X-ray diffraction (XRD), infrared spectra (IR), thermo gravimetric analysis (TGA) and scanning electron microscope (SEM) investigations showed that the two materials had different phase compositions, water content and particle sizes. The cells with BGM had a higher open circuit voltage (OCV) and discharged at higher voltages as compared to those with EMD. The discharge capacity of BGM was lower compared to that of EMD. On discharge both the materials produced same phase i.e. lithium intercalated manganese dioxide (LixMnO₂). This was also confirmed through X-ray photoelectron spectroscopy (XPS) investigation of the discharged products. 2011-06-29T06:20:55.101Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:13871 The electrochemical underpotential deposition (UPD) of lead on Au(110) was investigated by XPS using a custom-built ultrahigh vacuum apparatus containing a chamber for electrochemical studies. A two-step deposition process for lead UPD was confirmed. A large increase in the surface concentration of oxygen was found in solutions containing lead. The presence of lead was detected on the gold surface at all potentials within the range investigated (−500 mV to 1500 mV vs. Ag/AgCl). Degradation of chlorine by x-rays was observed. The change in surface components with potential was investigated and linked to models of UPD and oxidation. The initial random deposition of lead from solution led to surface disordering. 2011-06-29T06:20:54.598Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:13872 The discharge characteristics of manganese dioxide (γ-MnO₂ of electrolytic manganese dioxide (EMD) type) as a cathode material in a Zn–MnO₂ battery containing saturated aqueous LiOH electrolyte have been investigated. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) data on the discharged material indicate that lithium is intercalated into the host structure of EMD without the destruction of its core structure. The XPS data show that a layer of insoluble material, possibly Li₂CO₃, is deposited on the cathode, creating a barrier to H₂O, thus preventing the formation of Mn hydroxides, but allowing the migration of Li ions into the MnO₂ structure. The cell could be reversibly charged with 83% of voltaic efficiency at 0.5 mA/cm² current density to a 1.9 V cutoff voltage. The percentage utilization of the cathode material during discharge was 56%. 2011-06-29T06:20:49.973Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:3514 In this chapter we discuss various aspects of adaptive mobile guide applications. After having motivated the need for web based mobile applications, we will discuss technologies that are needed to enable adaptive mobile web applications, including not only positioning technologies but also sensor technologies needed to determine additional information on the context and situation of usage. We will also address issues of modeling context and situations before giving an overview on existing systems coming from three important classes of mobile guides: museum guides, navigation systems and shopping assistants. The chapter closes with an extensive discussion of relevant attributes of web based mobile guides. 2010-01-27T22:52:30.111Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:4354 The electrochemical behavior of titanium dioxide (TiO₂) in aqueous lithium hydroxide (LiOH) electrolyte has been investigated. Cyclic voltammetry shows that electroreduction results in the formation of a number of products. X-ray diffraction of the electroreduced TiO₂ shows that Liₓ TiO₂, Ti₂O₃, Ti₂O and TiO are formed. The formation of Liₓ TiO₂ is confirmed through X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) studies of the electroreduced TiO₂. The formation of Liₓ TiO₂ is electro reversible. In this respect, the electrochemical behavior of TiO₂ in concentrated aqueous lithium hydroxide electrolyte is similar to that for lithium perchlorate (LiClO₄) non-aqueous media. 2010-01-27T22:42:36.958Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:4364 The electrochemical behavior of γ-MnO₂ in lithium hydroxide (LiOH) and potassium hydroxide (KOH) aqueous media has been studied using slow-scan cyclic voltammetry (25 μV s⁻¹) in conjunction with X-ray analysis (XRD) and scanning electron microscopy (SEM). The reduction of γ-MnO₂ in aqueous LiOH results in intercalation of Li⁺ forming a new phase of lithium intercalated MnO₂(LiₓMnO₂). The process is found to be reversible. In this regard, the reduction of γ-MnO₂ in LiOH is quite different from that in aqueous KOH, which is irreversible and no lithium intercalation occurs. This difference in behavior is explained in terms of the relative ionic sizes of Li⁺ and K⁺. The LiₓMnO₂ lattice is stable only for Li⁺ because Li⁺ and Mn⁴⁺ are of approximately the same size whereas KₓMnO₂ is not stable because K⁺ has almost double the size. 2010-01-27T22:42:27.713Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:4365 The use of X-ray photoelectron spectroscopy (XPS) is expanding rapidly with the advent of more convenient, high-resolution laboratory-based instruments. The increase in the numbers and distribution of synchrotrons has also fuelled this burgeoning interest. Powell (C. J. Powell, J. Vac. Sci. Technol. A 21 (S42) 2003) has shown that the number of papers published on or using XPS has doubled in the past 10 years. He reports that there are in excess of 3000 papers published using XPS data each year across a wide range of applications, making it the most important technique for the determination of the composition of nano-scale surface films. Yet XPS and the associated technique of Auger-electron spectroscopy (AES) are not yet developed to the stage where the data and its interpretation are unambiguous. Auger photoelectron coincidence spectroscopy (APECS) provides a means of simplifying spectra, allowing for the decomposition of these into components that have a common origin. The spectra so produced provide a unique opportunity to test theory. In this paper, we will review recent progress in developing better APECS spectrometers and illustrate the power of APECS with new data acquired by these. 2010-01-27T22:42:27.681Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:4366 The redox behavior and surface characterization of LiFePO₄ in aqueous lithium hydroxide (LiOH) electrolyte have been investigated. The objective of this work is to investigate the electrochemical behavior of LiFePO₄ in an aqueous lithium hydroxide electrolyte and its comparison with that in non-aqueous lithium ion electrolytes. Cyclic voltammetry results show that LiFePO₄ undergoes partially reversible oxidation/reduction. The products formed on electrooxidation and subsequent reduction of LiFePO₄ were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). It is found that lithium extraction from LiFePO₄ occurs during oxidation. The products formed on subsequent reduction consist of LiFePO₄ and Fe₃O₄. 2010-01-27T22:42:25.974Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:4514 The electrochemistry of olivine-type iron phosphate (FePO₄) as a battery cathode material, in aqueous lithium hydroxide (LiOH), has been investigated. The material forms intercalated LiFePO₄ reversibly on electroreduction/oxidation. The formation of Fe₃O₄ phase, in addition to the regeneration of FePO₄ during reverse oxidation of LiFePO₄, also occurs. In this regard, the mechanism of FePO₄ discharge/charge in aqueous LiOH differs from that in non-aqueous solvents. 2010-01-27T22:40:45.208Z ]]>