Nanocrystalline and Thin Film Germanium Electrodes with High Lithium Capacity and High Rate Capabilities

Germanium nanocrystals (12 nm mean diam) and amorphous thin films (60-250 nm thick) were prepared as anodes for lithium secondary cells. Amorphous thin film electrodes prepared on planar nickel substrates showed stable capacities of 1700 mAh/g over 60 cycles. Germanium nanocrystals showed reversible gravimetric capacities of up to 1400 mAh/g with 60% capacity retention after 50 cycles. Both electrodes were found to be crystalline in the fully lithiated state. The enhanced capacity, rate capability (1000C), and cycle life of nanophase germanium over bulk crystalline germanium is attributed to the high surface area and short diffusion lengths of the active material and the absence of defects in nanophase materials

Highly Reversible Lithium Storage in Nanostructured Silicon

Anode materials of nanostructured silicon have been prepared by physical vapor deposition and characterized using electrochemical methods. The electrodes were prepared in thin-film form as nanocrystalline particles (12 nm mean diameter) and as continuous amorphous thin films (100 nm thick). The nanocrystalline silicon exhibited specific capacities of around 1100 mAh/g with a 50% capacity retention after 50 cycles. The amorphous thin-film electrodes exhibited initial capacities of 3500 mAh/g with a stable capacity of 2000 mAh/g over 50 cycles. We suggest that the nanoscale dimensions of the silicon circumvents conventional mechanisms of mechanical deterioration, permitting good cycle life

Integration of Corporate and Shareholder Taxes

Integration of the corporate and individual income taxes can be achieved by providing shareholders a credit for corporate taxes paid with respect to corporate earnings distributed as dividends. When such integration was previously considered in the U.S., proponents emphasized that it could reduce or eliminate many of the familiar distortions of a classical corporate income tax. Integration would also provide a framework for addressing current concerns for tax incentives for U.S. companies to shift income to foreign affiliates in lower-taxed countries or to expatriate in inversion transactions. A recent Congressional proposal for a corporate dividend deduction coupled with withholding on dividends could achieve equivalent results, while also reducing effective U.S. corporate tax rates

Income Tax Discrimination and the Political and Economic Integration of Europe

In recent years, the European Court of Justice (ECJ) has invalidated many income tax law provisions of EU member states as violating the guarantees of the European constitutional treaties of freedom of movement for goods, services, persons, and capital. These decisions have not, however, been matched by significant European income tax legislation, because no European political institution has the power to enact such legislation without unanimous consent from the member states. Under the treaties, the member states have retained a veto power over income tax legislation. In this Article, we describe how the developing ECJ jurisprudence threatens the ability of member states to use tax incentives to stimulate their domestic economies and to resolve problems of international double taxation. We conclude that the ECJ approach is ultimately incoherent because it constitutes an impossible quest – in the absence of harmonized income tax bases and rates throughout Europe – to eliminate discrimination based on both origin and destination of economic activity. We also compare the ECJ\u27s jurisprudence with the resolution of related issues in the U.S. taxation of interstate commerce and international taxation. Finally, we consider the potential responses of both the European Union and the United States to these developments

Magnetostriction of single crystal and polycrystalline Tb0.60Dy0.40 at cryogenic temperatures

At cryogenic temperatures, single crystals of TbDy alloys exhibit giant magnetostrictions of nearly 9000 ppm, making these materials promising for engineering service in cryogenic actuators, valves, and positioners. The preparation of single crystals is difficult and costly. Preliminary results on the magnetostriction of textured polycrystalline materials are presented here. For instance, polycrystalline Tb0.60Dy0.40, plane-rolled (one direction of applied stress) to induce crystallographic texture, has shown magnetostrictions at 77 K of 3000 ppm for an applied field of 4.5 kOe and an applied load of 23 MPa, or 48% that of a single crystal under similar conditions. Comparisons are presented between the magnetostrictive response of plane- and form-rolled (two orthogonal directions of applied stress) polycrystalline Tb0.60Dy0.40 at 10 and 77 K. It is reported that at 10 K plane-rolled Tb0.60Dy0.40 exhibits 1600 ppm magnetostriction at an applied field of 4.4 kOe with a minimal applied load of 0.28 MPa. An observed restoration of the initial unstrained state may be a useful feature of polycrystalline materials for engineering service. Finally it is reported that thermal expansion measurements provide a measure of crystallographic texture for comparison with the magnetostriction

Income Tax Discrimination and the Political and Economic of Europe

In recent years, the European Court of Justice (ECJ) has invalidated many income tax law provisions of European Union (EU) member states as violating European constitutional treaty guarantees of freedom of movement for goods, services, persons, and capital. These decisions have not, however, been matched by significant EU income tax legislation, because no EU political institution has the power to enact such legislation without unanimous consent from the member states. In this Article, we describe how the developing ECJ jurisprudence threatens the ability of member states to use tax incentives to stimulate their domestic economies and to resolve problems of international double taxation. We conclude that the ECJ approach is ultimately incoherent because it is a quest for an unattainable goal in the absence of harmonized income tax bases and rates: to eliminate discrimination based on both origin and destination of economic activity. We also compare the ECJ\u27s jurisprudence with the resolution of related issues in international taxation and the U.S. taxation of interstate commerce, and we consider the potential responses of both the European Union and the United States to these developments

X-ray absorption study of Ti-activated sodium aluminum hydride

Ti K-edge x-ray absorption near edge spectroscopy (XANES) was used to explore the Ti valence and coordination in Ti-activated sodium alanate. An empirical relationship was established between the Ti valence and the Ti K-edge onset based on a set of standards. This relationship was used to estimate oxidation states of the titanium catalyst in 2 mol% and 4 mol% Ti-doped NaAlH4. These results demonstrate that the formal titanium valence is zero in doped sodium alanate and nearly invariant during hydrogen cycling. A qualitative comparison of the edge fine structure suggests that the Ti is present on the surface in the form of amorphous TiAl3.Comment: 3 pages, 4 figures, submitted to Appl. Phys. Let

Thermochemistry of Alane Complexes for Hydrogen Storage: A Theoretical and Experimental Comparison

Knowledge of the relative stabilities of alane (AlH3) complexes with electron donors is essential for identifying hydrogen storage materials for vehicular applications that can be regenerated by off-board methods; however, almost no thermodynamic data are available to make this assessment. To fill this gap, we employed the G4(MP2) method to determine heats of formation, entropies, and Gibbs free energies of formation for thirty-eight alane complexes with NH3-nRn (R = Me, Et; n = 0-3), pyridine, pyrazine, triethylenediamine (TEDA), quinuclidine, OH2-nRn (R = Me, Et; n = 0-2), dioxane, and tetrahydrofuran (THF). Monomer, bis, and selected dimer complex geometries were considered. Using these data, we computed the thermodynamics of the key formation and dehydrogenation reactions that would occur during hydrogen delivery and alane regeneration, from which trends in complex stability were identified. These predictions were tested by synthesizing six amine-alane complexes involving trimethylamine, triethylamine, dimethylethylamine, TEDA, quinuclidine, and hexamine, and obtaining upper limits of delta G for their formation from metallic aluminum. Combining these computational and experimental results, we establish a criterion for complex stability relevant to hydrogen storage that can be used to assess potential ligands prior to attempting synthesis of the alane complex. Based on this, we conclude that only a subset of the tertiary amine complexes considered and none of the ether complexes can be successfully formed by direct reaction with aluminum and regenerated in an alane-based hydrogen storage system.Comment: Accepted by the Journal of Physical Chemistry