Closely related tetrapyridyl ligands with different core units (i.e., benzene and tetrathiafulvalene moieties for complexes 1 and 2, respectively) under similar reaction conditions yield dramatically different structural motifs (i.e., hexanuclear and dodecanuclear boxes for complexes 1 and 2, respectively).

Thermodynamic activities of zinc in the ~l-PtZn and the a-PtZn phases were determined at 1273~ using an isopiestic method. The theoretical thermodynamic equations by Chang and co-workers for the nonstoichiometrie Llo phases were modified to include the different interactions between the first nearest neighbor and the second nearest neighbor atoms. An analysis of the activity data for the ~-PtZn phase at 1273~ in terms of the modified theoretical equation yields the following values: a = 3 • 10 -4, ~ -: 1.0, and in azn.o ----4.65. The thermodynamic data of the ,~-phase were evaluated in terms of the subregular solution model. The partial quantities of platinum and the integral quantities for the a-and ~l-phases were obtained by means of the Gibbs-Duhem relationship. A theoretical relationship between the enthalpy of formation and the model parameters for the Llo phases was derived and correlated with the /~l-PtZn data and other data available in the literature.The three group VIII transition metals, nickel, palladium, and platinum, react with the group II metal zinc to form ordered intermetallic phases with the Llo structure at the equiatomic composition. This structure may be viewed either in terms of a body-centered tetragonal or a face-centered tetragonal lattice. At the stoic hiometric composition, in terms of the body-centered lattice, all the A atoms occupy the body-centered positions and the B atoms the corner positions for a perfectly ordered structure. However, at any finite temperature, some degree of lattice disorder prevails. At nonstoichiometric compositions, constitutionally induced lattice disorder occurs in the lattice, in addition to that due to thermal vibration. This lattice disorder contributes to the thermodynamic properties of the intermetallic phases. Chang and co-workers (1, 2) derived theoretical equations to describe the compositional dependences of the activity and the partial molar enthalpy of the Llo phases. The validity of the theoretical equations was verified using the extensive data for/~l-NiZn and ~l-PdZn (3-5). Like these phases, the fi~-PtZn 2 phase also exists over a wide range of homogeneity. The exact range of homogeneity is discussed later in this paper. The objective of the present investigation is to determine the thermodynamic properties of the ~-PtZn phase using an isopiestic technique and to further test the validity of the theoretical equations of Chang and co-workers. Moreover, these theoretical equations are slightly modified in order to consider the possible difference between the interactions of first and second nearest neighbor atoms, which were assumed to be identical in the original develop1Present address:

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With the rapid development of the Internet applications and the explosion of end users, IP address has been exhausted and routing lookup speed is the bottleneck of router design. In addition TCAM is widely used for implementation fast IP forwarding table lookup. However, the need to maintain a sorted list incremental updates may slow the lookup speed in a TCAM. In this paper, a fast TCAM update scheme is proposed for TCAM-Based IPv6 routing lookup architecture. Based on the characteristic of prefix distribution, we design a TCAM-Based router architecture for IPv6 routing lookup. As simulation result shows more than 90% update do not need any memory movement in updating operation. The worse case is (D-2)/2, where D is the length of chain.

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