Serration in A l-Zn Alloys Containing a Small Amount of Fe

Effect of addition of Fe on the occurrence of serration in Al-12mass%Zn alloys was investigated. Specimens aged at 293K for various periods after quenching from various temperatures (T(Q)), 398K to 823K, were tensile-tested at room temperature. Serration occurred more easily and more remarkably with decreasing T(Q) for as-quenched specimens: in the case that T(Q)=448K serration was observed both for the binary and Fe added alloys, while in the case that T(Q)=573K none of the three alloys showed serration. For the binary alloy serration was observed only when the aging period was short enough, but addition of Fe to the binary alloy prolonged the aging period where serration could be recognized. Aging rate measured by hardness was remarkably retarded with the increase of Fe addition. These results confirm the interpretation that the serration in Al-Zn alloy occurs in the early stage of aging where small GP zones or solute clusters are formed

Notes on the Super Nambu Bracket

We define a super Nambu-Poisson algebra over a super manifold. A super Nambu bracket does not satisfy the usual skew-symmetric property, and we propose another skew-symmetric property. We show that the divergence of super Nambu-Hamiltonian vector fields leads to a generalization of the Batalin-Vilkovisky algebra.Comment: 9 pages, no figures, AMS-LaTeX, ptptex.cls, some errors corrected, version to appear in PT

Regional integration in East Asia :challenges and opportunities - Part II : Trade, finance and integration

The authors analyze the patterns of East Asia's trade and foreign direct investment (FDI) from a global and intraregional perspective, taking into account the importance of trade and FDI interlinkages. They propose two regionally-focused approaches to promoting trade and FDI in East Asia-regional agreements and regional production networks. The East Asia crisis strengthened appeals for regional cooperation in the financial area. As a result, a number of financial arrangements and initiatives have emerged since the crisis, the most prominent of these, the Chiang Mai Initiative. (The Association of Southeast Asian Nations plus China, the Republic of Korea, and Japan decided at their meeting in Chiang Mai, Thailand, in May 2000, to establish a regional network of swap arrangements.) While opening of the capital account is considered desirable in the long run, it is associated with considerable risk, particularly if macroeconomic policies are not sound and financial supervision and regulation is weak. Because of the potential volatility associated with floating regimes and the desire to avoid another crisis in the region, the authors discuss a number of options.Payment Systems&Infrastructure,Environmental Economics&Policies,Common Carriers Industry,Economic Theory&Research,Trade Policy,Economic Theory&Research,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Environmental Economics&Policies,Trade Policy,Trade and Services

A Study of Magnetic Properties of Solid Oxygen, Oxygen-Argon and Oxygen-Fluorine

To acquire information on the interaction between oxygen molecules in solid phase, studies have been carried out on the magnetic properties of solid oxygen, oxygen-argon and oxygen-fluorine. Review of the studies on the interaction between oxygen molecules is cited. Magnetic susceptibility was measured by the Faraday method as a function of temperature from 12 K to the melting point of them. Pure oxygen both in α and β phase indicates paramagnetism corresponding to long-range antiferromagnetic order. Oxygen -argon mixtures of 92~66 mol% oxygen content indicate large susceptibility corresponding to δ phase, which can be interpreted in terms of the cluster of oxygen molecules in trimer. Small paramagnetism was found for the oxygenfluorine mixture even as dilute as 10 mol% oxygen content, which may be due to the strong antiferromagnetic interaction. This can be interpreted in terms of super-exchange interaction between oxygen molecules via fluorine molecule

Fluctuation of the Solute Concentration in Al Rich Al-Zn Alloys

Several Al-Zn alloys containing 0.041-4.4 at % Zn were studied by means of measurements of electrical resistivity. The results obtained are as follows : (1) The electrical resistivity increases when the specimen is annealed at temperatures higher than the solvus temperature of the G.P. zones. The increase of the resistivity is due to the formation of fluctuation. (2) The electrical resistivity of the specimen containing fluctuation is dependent upon annealing temperature only and independent of quenching temperature. (3) The fluctuation is formed in very dilute alloys as 0.041 at % Zn at temperatures higher than the solvus temperature of the G.P. zones. (4) The formation energy of vacancy and the migration energy of the Zn atom in the alloys determined by the formation process of fluctuation are in good agreement with those by the formation process of G.P. zones. (5) In spite of the result (4), it seems that the fluctuation is not the same as the small G.P. zones which are observed in the early stage of aging

Magentic-Field Induced Quantum Phase Transition and Critical Behavior in a Gapped Spin System TlCuCl3_3

Magnetization measurements were performed on TlCuCl$_3$ with gapped ground state. The critical density and the magnetic phase diagram were obtained. The interacting constant was obtained as $U/k_{\rm B} = 313$ K. The experimental phase boundary for $T < 5$ K agrees perfectly with the magnon BEC theory based on the Hartree-Fock approximation with realistic dispersion relations and $U/k_{\rm B} = 320$ K. The exponent $\phi$ obtained with all the data points for $T < 5$ K is $\phi = 1.99$, which is somewhat larger than theoretical exponent $\phi_{\rm BEC} =3/2$. However, it was found that the exponent converges at $\phi_{\rm BEC} =3/2$ with decreasing fitting window.Comment: 2 pages, 2 figures, Submitted to Proceedings of International Conference on Magnetism (ICM2006