Lithium ion conduction in ionic liquid-based gel polymer electrolyte

The conduction mechanism of gel electrolyte system consisting of poly(ethylene oxide) branched poly(methyl methacrylate) (PEO-PMA) matrix and ionic liquid containing lithium salt has been investigated. The kinetics of ion conduction and the mobility of lithium ion are different by the kind of ionic liquid; 1-ethyl-3-methyl imidazolium bis(trifluoromethane sulfone)imide (EMITFSI) or hexyltrimethylammonium bis(trifluoromethane sulfone)imide (HTMATFSI). Lithium ion exhibits a significant contribution for ion conduction in the gel electrolyte containing HTMATFSI. In contrast, the mobility of lithium ion is not obvious in the gel electrolyte containing EMITFSI. Such difference is considered to originate from the difference in ‘miscibility’ of polymer component in ionic liquid.     

Effects of the surface treatment of the Al2O3 filler on the lithium electrode/solid polymer electrolyte interface properties

The lithium deposition-dissolution process in solid polymer electrolytes containing Al₂O₃ filler treated under different conditions has been investigated comparing with the ionic conduction behavior of the electrolyte. The composite electrolytes were prepared from poly(ethylene oxide) (PEO), LiBF₄ and α-Al₂O₃ filler by using a dry process, where the surface of α-Al₂O₃ was beforehand modified by a wet process. The exchange current densities, i₀, of the lithium electrode process in P(EO)₂₀LiBF₄ with and without Al₂O₃ filler were determined by a micro-polarization method. The temperature dependence of i₀ provided similar values for activation energy, ca. 25 and 70 kJ mol⁻¹ in both temperature regions above and below 60 °C, respectively. The effect of the surface treatment of the filler on the lithium electrode process gave a different tendency from that on the ionic conductivity. The Al₂O₃ surface treated by alkali solution enhanced the electrode process to the largest extent among the fillers used here, while it led to rather poor cycling stability in voltammetry. The enhanced reaction rate at the lithium electrode/solid polymer electrolyte interface has probably resulted in the improved ion dissociation by the surface groups of the Al₂O₃ filler.     

Evaluation of the Wear Energy Consumption of Nitrogenated Diamond-Like Carbon Against Alumina

The wear energy consumption of nitrogenated diamond-like carbon (NDLC) in the tribo-test against alumina was evaluated. The energy input induced by the power source of the tribometer is applied to the contact area of two sliding bodies. The energy is dissipated into the two bodies with various transforming energies, such as (1) wear energy, (2) friction heat, (3) strain energy, (4) plastic deformation energy, and (5) chemical reaction energy used to form the tribo-layer. Determining the breakdown of the energy consumption into each mode is notably important for the investigation of the tribological mechanism. The surface fracture energy of NDLCs was evaluated by the micro-indentation method. The newly created surface area was estimated using the wear particles size distribution measured by image processing. The consumed wear energy was obtained by the surface fracture energy multiplied by the new created surface area corresponding to the generation of the wear particles in the tribo-test. The index numbers of the wear consumption energy/energy input ratio of the NDLCs were almost the same as those of their wear coefficients.     

Hydrogen, fluorine ion implantation effects on polycrystalline silicon grain boundaries

The influences of hydrogen and fluorine ion implantation on polycrystalline silicon (poly-Si) grain boundaries have been investigated. Effective passivation of poly-Si grain boundaries was achieved by hydrogen ion implantation at 300–400°C. From fluorine implantation experiments, we confirmed that fluorine atoms in poly-Si were redistributed with a diffusion tail after annealing at above 600°C. A diffusion tail of fluorine redistribution was not observed in single crystalline silicon. We think that it is possible to passivate poly-Si grain boundaries by controlling the diffusion of fluorine.     

Suppressing the Formation of Cone Structures in Chemical-Vapor-Deposited Aluminum Nitride/Titanium Nitride Films

Cone structures are sometimes observed in aluminum nitride/titanium nitride (AIN/TiN) composite films formed by chemical vapor deposition (CVD). In this study, we determined the formation mechanism of cone structures by looking at such films deposited on Si substrates. We found that the mechanism can be explained by changes in the deposition rate due to composition differences in the growing surfaces, rather than by inhomogeneities in the original substrate surface. We then used this discovery to develop a technique to suppress cone structure formation, i. e., deposition of an interlayer before the deposition of the composite. To validate our technique, we then successfully suppressed the formation of cone structures in AIN/TiN films by depositing a TiN interlayer on the substrate before the deposition of AIN/TiN.     

Enhanced myosin light chain phosphorylations as a central mechanism for coronary artery spasm in a swine model with interleukin-1beta

BACKGROUND: Although coronary artery spasm plays an important role in a wide variety of ischemic heart diseases, the intracellular mechanism for the spasm remains to be clarified. We examined the role of myosin light chain (MLC) phosphorylations, a key mechanism for contraction of vascular smooth muscle, in our swine model with interleukin-1beta (IL-1beta). METHODS AND RESULTS: IL-1beta was applied chronically to the porcine coronary arteries from the adventitia to induce an inflammatory/proliferative lesion. Two weeks after the operation, intracoronary serotonin repeatedly induced coronary hyperconstrictions at the IL-1beta-treated site both in vivo and in vitro, which were markedly inhibited by fasudil, an inhibitor of protein kinases, including protein kinase C and MLC kinase. Western blot analysis showed that during serotonin-induced contractions, MLC monophosphorylation was significantly increased and sustained in the spastic segment compared with the control segment, whereas MLC diphosphorylation was noted only in the spastic segment. A significant correlation was noted between the serotonin-induced contractions and MLC phosphorylations. Both types of MLC phosphorylation were markedly inhibited by fasudil. In addition, MLC diphosphorylation was never induced by a simple endothelium removal in the normal coronary artery, whereas enhanced MLC phosphorylations in the spastic segment were noted regardless of the presence or absence of the endothelium. CONCLUSIONS: These results indicate that enhanced MLC phosphorylations in the vascular smooth muscle play a central role in the pathogenesis of coronary spasm in our swine model.     

Coupled and Decoupled Numerical Modeling of Flow and Morphological Evolution in Alluvial Rivers

Existing numerical river models are mostly built upon asynchronous solution of simplified governing equations. The strong coupling between water flow, sediment transport, and morphological evolution is thus ignored to a certain extent. An earlier study led to the development of a fully coupled model and identified the impacts of simplifications in the water-sediment mixture and global bed material continuity equations as well as of the asynchronous solution procedure for aggradation processes. This paper presents the results of an extended study along this line, highlighting the impacts on both aggradation and degradation processes. Simplifications in the continuity equations for the water-sediment mixture and bed material are found to have negligible effects on degradation. This is, however, in contrast to aggradation processes, in which the errors purely due to simplified continuity equations can be significant transiently. The asynchronous solution procedure is found to entail appreciable inaccuracy for both aggradation and degradation processes. Further, the asynchronous solution procedure can render the physical problem mathematically ill posed by invoking an extra upstream boundary condition in the supercritical flow regime. Finally, the impacts of simplified continuity equations and an asynchronous solution procedure are shown to be comparable with those of largely tuned friction factors, indicating their significance in calibrating numerical river models. It is concluded that the coupled system of complete governing equations needs to be synchronously solved for refined modeling of alluvial rivers.     

Removal of endocrine disruptors in milk by circulation through polydimethylsiloxane tubing

A simple circulating system was developed, in which an aqueous solution, cow milk, or human milk was circulated through hydrophobic polymeric tubing to remove the endocrine disruptors from the solution by sorption into the tubing. The effect of circulating parameters, such as tube length, circulating time, and flow rate, against the removal ratio (R) of endocrine disruptors was investigated. R of 1,2,3,4,5,6‐hexachlorocyclohexane (γ‐HCH, lindane) increased with the length of the hydrophobic polymeric tubing, circulating time, and flow rate when cow milk containing 1 ppm γ‐HCH was circulated through polydimethylsiloxane tubing. The R values of several endocrine disruptors with different octanol–water distribution coefficients (log P_ow) was investigated for γ‐HCH and dichlorodiphenyltrichloroethane in an aqueous solution, cow milk, and human milk. A similar trend for R versus log P_ow of the human milk to that of the aqueous solution and cow milk was observed. The R values of the endocrine disruptors decreased in the following order: Aqueous solution > Human milk > Cow milk. Stable micelles in cow milk disturbed the shift of the endocrine disruptors from the milk micelles into the hydrophobic tubing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3634–3640, 2006