989 resultados para 157-954


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A detailed investigation of the hydrolysis of nickel in the lower concentration range has been made. The results have been analysed on the basis of 'Core + links' theory and on the assumption of the formation of one predominant complex. Evidence is obtained for the formation of Ni2 (OH)62- and its stability constant is calculated to be 1038.78

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A detailed account of the morphological, staining, penicillin sensitivity and serological peculiarities of five strains of an oxalate-decomposing bacterium including the well-recognized strain Vibrio extorquens, has been given. Inasmuch as all the strains share many of the characteristics of the genus Arthrobacter and not Vibrio the desirability of placing the bacterium in the former genus for the time being has been suggested. The possibility of the strains falling under an altogether new genus which represent a phylogenic link between the pseudomonads and diphtheroids has been speculated.

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Nanoplate LiFePO4 is synthesized by a polyol route starting from only two reactants, namely, FePO4 and LiOH. The crystalline compound forms by refluxing a tetraethylene glycol solution consisting of FePO4 and LiOH at 335 degrees C without further heating of the reaction product.The nanoplates have average dimensions of 30 nm width and 160 nm length, as measured from transmission electron microscopy micrographs.The surface area of the LiFePO4 sample is 38 m(2) g(-1). Also, the sample is porous with a broadly distributed pore around 50 nm. The electrodes fabricated out of the nanoplate of LiFePO4 exhibit a high electrochemical activity. Discharge capacity values measured are 160 and 100 mAh g(-1) at 0.15C and 3.45C, respectively. A stable capacity of about 155 mAh g(-1) is measured at 0.2C over a 50 charge-discharge cycle. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3425730] All rights reserved.

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A finite circular cylindrical shell subjected to a band of uniform pressure on its outer rim was investigated, using three-dimensional elasticity theory and the classical shell theories of Timoshenko (or Donnell) and Flügge. Detailed comparison of the resulting stresses and displacements was carried out for shells with ratios of inner to outer shell radii equal to 0.80, 0.85, 0.90 and 0.93 and for ratios of outer shell diameter to length of the shell equal to 0.5, 1 and 2. The ratio of band width to length of the shell was 0.2 and Poisson's ratio used was equal to 0.3. An Elliot 803 digital computer was used for numerical computations.

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Durability is central to the commercialization of polymer electrolyte fuel cells (PEFCs). The incorporation of TiO2 with platinum (Pt) ameliorates both the stability and catalytic activity of cathodes in relation to pristine Pt cathodes currently being used in PEFCs. PEFC cathodes comprising carbon-supported Pt-TiO2 (Pt-TiO2/C) exhibit higher durability in relation to Pt/C cathodes as evidenced by cell polarization, impedance, and cyclic voltammetry data. The degradation in performance of the Pt-TiO2/C cathodes is 10% after 5000 test cycles as against 28% for Pt/C cathodes. These data are in conformity with the electrochemical surface area and impedance values. Pt-TiO2/C cathodes can withstand even 10,000 test cycles with nominal effect on their performance. X-ray diffraction, transmission electron microscope, and cross-sectional field-emission-scanning electron microscope studies on the catalytic electrodes reflect that incorporating TiO2 with Pt helps in mitigating the aggregation of Pt particles and protects the Nafion membrane against peroxide radicals formed during the cathodic reduction of oxygen. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3421970] All rights reserved.

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Layered LiNi1/3Co1/3Mn1/3O2, which is isostructural with LiCoO2, is considered as a potential cathode material for Li-ion batteries. Submicrometer sized porous particles are useful for high discharge rates. The present work involves a synthesis of submicrometer sized porous particles of LiNi1/3Co1/3Mn1/3O2 using a triblock copolymer as a soft template. The precursor obtained from the reaction is heated at different temperatures between 600 and 900 degrees C for 6 h to get the final product samples. The compound attains increased crystallinity with an increase in the temperature of preparation. However, there is a decrease in the surface area and also in the porosity of the sample. Nevertheless, the LiNi1/3Co1/3Mn1/3O2 sample prepared at 900 degrees C exhibits a high rate capability and stable capacity retention on cycling. The electrochemical performance of LiNi1/3Co1/3Mn1/3O2 prepared in the absence of the polymer template is inferior to that of the sample prepared in the presence of the polymer template. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3364944] All rights reserved.

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Poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (styrene sulphonic acid) (PSSA) supported platinum (Pt) electrodes for application in polymer electrolyte fuel cells (PEFCs) are reported. PEDOT-PSSA support helps Pt particles to be uniformly distributed on to the electrodes, and facilitates mixed electronic and ionic (H+-ion) conduction within the catalyst, ameliorating Pt utilization. The inherent proton conductivity of PEDOT-PSSA composite also helps reducing Nation content in PEFC electrodes. During prolonged operation of PEFCs, Pt electrodes supported onto PEDOT-PSSA composite exhibit lower corrosion in relation to Pt electrodes supported onto commercially available Vulcan XC-72R carbon. Physical properties of PEDOT-PSSA composite have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. PEFCs with PEDOT-PSSA-supported Pt catalyst electrodes offer a peak power-density of 810 mW cm(-2) at a load current-density of 1800 mA cm(-2) with Nation content as low as 5 wt.% in the catalyst layer. Accordingly, the present study provides a novel alternative support for platinized PEFC electrodes.

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The negative relationship between economic growth and stock market return is not an anomaly according to evidence documented in many economies. It is argued that future economic growth is largely irrelevant for predicting future equity returns, since long-run equity returns depend mainly on dividend yields and the growth of per share dividends. The economic growth does result in a higher standard of living for consumers, but does not necessarily translate into higher returns for owners of the capital. The divergence in performance between the real sector and stock markets appears to support the above argument. However, this thesis strives to offer an alternative explanation to the apparent divergence within the framework of corporate governance. It argues that weak corporate governance standards in Chinese listed firms exacerbated by poor inventor protection results into a marginalized capital market. Each of the three essays in the thesis addresses one particular aspect of corporate governance on the Chinese stock market in a sequential way through gathering empirical evidence on three distinctive stock market activities. The first essay questions whether significant agency conflicts do exist by building a game on rights issues. It documents significant divergence in interests among shareholders holding different classes of shares. The second essay investigates the level of agency costs by examining value of control through constructing a sample of block transactions. It finds that block transactions that transfer ultimate control entail higher premiums. The third essay looks into possible avenues through which corporate governance standards could be improved by investigating the economic consequences of cross-listing on the Chinese stock market. It finds that, by adopting a higher disclosure standard through cross-listings, firms voluntarily commit themselves to reducing information asymmetry, and consequently command higher valuation than their counterparts.

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Poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (styrene sulphonic acid) (PSSA) supported platinum (Pt) electrodes for application in polymer electrolyte fuel cells (PEFCs) are reported. PEDOT-PSSA support helps Pt particles to be uniformly distributed on to the electrodes, and facilitates mixed electronic and ionic (H+-ion) conduction within the catalyst, ameliorating Pt utilization. The inherent proton conductivity of PEDOT-PSSA composite also helps reducing Nation content in PEFC electrodes. During prolonged operation of PEFCs, Pt electrodes supported onto PEDOT-PSSA composite exhibit lower corrosion in relation to Pt electrodes supported onto commercially available Vulcan XC-72R carbon. Physical properties of PEDOT-PSSA composite have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. PEFCs with PEDOT-PSSA-supported Pt catalyst electrodes offer a peak power-density of 810 mW cm(-2) at a load current-density of 1800 mA cm(-2) with Nation content as low as 5 wt.% in the catalyst layer. Accordingly, the present study provides a novel alternative support for platinized PEFC electrodes

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This study develops a real options approach for analyzing the optimal risk adoption policy in an environment where the adoption means a switch from one stochastic flow representation into another. We establish that increased volatility needs not decelerate investment, as predicted by the standard literature on real options, once the underlying volatility of the state is made endogenous. We prove that for a decision maker with a convex (concave) objective function, increased post-adoption volatility increases (decreases) the expected cumulative present value of the post-adoption profit flow, which consequently decreases (increases) the option value of waiting and, therefore, accelerates (decelerates) current investment.

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This paper examines how volatility in financial markets can preferable be modeled. The examination investigates how good the models for the volatility, both linear and nonlinear, are in absorbing skewness and kurtosis. The examination is done on the Nordic stock markets, including Finland, Sweden, Norway and Denmark. Different linear and nonlinear models are applied, and the results indicates that a linear model can almost always be used for modeling the series under investigation, even though nonlinear models performs slightly better in some cases. These results indicate that the markets under study are exposed to asymmetric patterns only to a certain degree. Negative shocks generally have a more prominent effect on the markets, but these effects are not really strong. However, in terms of absorbing skewness and kurtosis, nonlinear models outperform linear ones.

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The problem of determining whether a Tanner graph for a linear block code has a stopping set of a given size is shown to be NT-complete.

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Electrochemical oxidation of borohydride is studied on nanosized rhodium, iridium, and bimetallic rhodium-iridium catalysts supported onto Vulcan XC72R carbon. The catalysts are characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy in conjunction with cyclic voltammetry and polarization studies. The studies reveal that a 20 wt % bimetallic Rh-Ir catalyst supported onto carbon (Rh-Ir/C) is quite effective for the oxidation of borohydride. Direct borohydride fuel cell with Rh-Ir/C as the anode catalyst and Pt/C as the cathode catalyst exhibits a peak power density of 270 mW/cm(2) at a load current density of 290 mA/cm(2) as against 200 mW/cm(2) at 225 mA/cm(2) for Rh/C and 140 mW/cm(2) at 165 mA/cm(2) for Ir/C while operating at 80 degrees C. The synergistic catalytic activity for the bimetallic Rh-Ir nanoparticles toward borohydride oxidation is corroborated by density-functional theory calculations using electron-localization function. (C) 2010 The Electrochemical Society. [DOI:10.1149/1.3442372] All rights reserved.