Lithium ion conducting polymer electrolytes based on alternating maleic anhydride copolymer with oligo-oxyethylene side chains

A comb polymer with oligo-oxyethylene side chains of the type -(CH2CB2O)(12)CH3 was prepared from methyl vinyl ether/maleic anhydride copolymer and poly (ethylene glycol) methyl ether. The polymer can dissolve LiClO4 salt to form homogeneous amorphous polymer electrolyte. The ac ion conduction was measured using the complex impedance method, and conductivities were investigated as functions of temperatures and salt concentration. The complexes were first found to have two classes of glass transition which increase with increasing salt content, The optimum conductivity attained at 25 degrees C is in the order of 5.50 x 10(-6)Scm(-1). IR spectroscopy was used to study the cation-polymer interaction.

A study of the dependence of ferrocene diffusion on chain length in polymer electrolytes

The diffusion rates of ferrocene have been estimated in five kinds of poly(ethylene glycol) solution, containing the electrolyte LiClO4, by using non-steady-state chronoamperometry. The D-app of ferrocene increases with increasing temperature, and the dependency of D-app on temperature obeys the Williams-Landel-Ferry equation. The D-app of ferrocene decreases with increasing polymer chain length. Both the chain length and temperature dependence conform to a simple free volume model. A relation between current and polymer chain length is suggested at room and high temperatures.

Ionic conductivity of polymer gel electrolytes based on poly(polyethylene glycol dimethacrylate)

Gel electrolytes have been prepared by thermal polymerization of poly(polyethylene glycol dimethacrylate) (P(PEGD)) in the presence of propylene carbonate (PC) and alkali metal salts, such as LiClO4, LICF(3)SO(3) and LiBF4. The conductivity was studied by means of impedance spectroscopy, and it is found that the temperature dependence of conductivities follow a Arrhenius relationship when the molar percentage of PC is higher than 75% or LiClO4 concentration is lower than 0.9 mol/l. However, when LiCF3SO3 or LiBF4 is used instead of LiClO4 as the salt, the situation is different. For LICF(3)SO(3), the Arrhenius relationship almost holds true for all the salt concentrations studied; while for LiBF4, the Arrhenius equation hardly fits for any salt concentration. The dependence of activation energy on salt concentration is also examined, both for LiClO4 and LiCF3SO3, the values of E(a) tend to reach a minimum value with increasing salt concentration. Copyright (C) 1996 Elsevier Science Ltd.

Determination of fractional energy loss of waves in nearshore waters using an improved high-order Boussinesq-type model

Fractional energy losses of waves due to wave breaking when passing over a submerged bar are studied systematically using a modified numerical code that is based on the high-order Boussinesq-type equations. The model is first tested by the additional experimental data, and the model's capability of simulating the wave transformation over both gentle slope and steep slope is demonstrated. Then, the model's breaking index is replaced and tested. The new breaking index, which is optimized from the several breaking indices, is not sensitive to the spatial grid length and includes the bottom slopes. Numerical tests show that the modified model with the new breaking index is more stable and efficient for the shallow-water wave breaking. Finally, the modified model is used to study the fractional energy losses for the regular waves propagating and breaking over a submerged bar. Our results have revealed that how the nonlinearity and the dispersion of the incident waves as well as the dimensionless bar height (normalized by water depth) dominate the fractional energy losses. It is also found that the bar slope (limited to gentle slopes that less than 1:10) and the dimensionless bar length (normalized by incident wave length) have negligible effects on the fractional energy losses.

A HYBRID METHOD OF FRACTIONAL STEPS WITH PREDICTOR-CORRECTOR DIFFERENCE-PSEUDOSPECTRUM FOR NUMERICAL-SOLUTION OF THE CONVECTION-DOMINATED FLOW PROBLEMS

A fractional-step method of predictor-corrector difference-pseudospectrum with unconditional L(2)-stability and exponential convergence is presented. The stability and convergence of this method is strictly proved mathematically for a nonlinear convection-dominated flow. The error estimation is given and the superiority of this method is verified by numerical test.

Digestibility, nutrient balance and urinary purine derivative excretion in dry yak cows fed oat hay at different levels of intake

A feeding trial A as conducted at the farm of Qinghai Academy of Animal and Veterinary Science, Xining, China during 1996 - 1997 with three dry yak cows (initial body weight 163 - 197 kg, age 5 - 6 years) by using 3 x 3 Latin Square Design to determine the effect of levels of feed intake on digestion, nitrogen balance and purine derivative excretion in urine of yak cows. The animals were fed oat hay (nitrogen 13.5 g/kg dry matter (DM), metabolisable energy 8.3 MJ/kg DM), i.e., 0.3, 0.6 and 0.9 of voluntary intake (VI). Each intake treatment lasted for 17 days and the samples (feeds, faeces and urine) were collected during last 7 days of each period. The results indicate that digestibility of dietary DM, OM, NDF and ash declined when intake levels increased from 0.3 to 0.9 VI [DM, from 66.1% to 59.1% (P < 0.05); OM, from 68.1% to 59.9% (P < 0.05); NDF, from 62.1% to 54.3% (P < 0.05); and ash, from 33.9% to 11.8% (P < 0.05)]. Around 0.10 g N/kg W-0.75 was deficient daily in yak cows at 0.3 VI, and positive N balances were observed at 0.6 and 0.9 VI. Intake levels significantly (P < 0.05) affected total PD excretion in yak urine. The proportion of allantoin increased (P < 0.05) and uric acid decreased (P < 0.05) as intake level of feed increased. (C) 2004 Elsevier B.V. All rights reserved.

Fractional versus decimal pricing: Evidence from the UK Long Gilt futures market

ap Gwilym, Owain, McManus, Ian, and Thomas, Stephen, 'Fractional versus decimal pricing: Evidence from the UK Long Gilt futures market', Journal of Futures Markets (2005) 25(5) pp.419-442 RAE2008

Fractional and unquantized dc voltage generation in THz-driven semiconductor superlattices

We consider the spontaneous creation of a dc voltage across a strongly coupled semiconductor superlattice subjected to THz radiation. We show that the dc voltage may be approximately proportional either to an integer or to a half- integer multiple of the frequency of the applied ac field, depending on the ratio of the characteristic scattering rates of conducting electrons. For the case of an ac field frequency less than the characteristic scattering rates, we demonstrate the generation of an unquantized dc voltage.

Gauge/gravity duality and the interplay of various fractional branes

We consider different types of fractional branes on a Z2 orbifold of the conifold and analyze in detail the corresponding gauge/gravity duality. The gauge theory possesses a rich and varied dynamics, both in the UV and in the IR. We find the dual supergravity solution, which contains both untwisted and twisted 3-form fluxes, related to what are known as deformation and N=2 fractional branes, respectively. We analyze the resulting renormalization group flow from the supergravity perspective, by developing an algorithm to easily extract it. We find hints of a generalization of the familiar cascade of Seiberg dualities due to a nontrivial interplay between the different types of fractional branes. We finally consider the IR behavior in several limits, where the dominant effective dynamics is either confining in a Coulomb phase or runaway, and discuss the resolution of singularities in the dual geometric background. © 2008 The American Physical Society.