ALBERT

Notes: The abnormal grain growth of β-Si3N4 was observed in a 70% Si3N4–30% barium aluminum silicate (70%-Si3N4–30%-BAS) self-reinforced composite that was pressureless-sintered at 1930°C; Si3N4 starting powders with a wide particle-size distribution were used. The addition of coarse Si3N4 powder encouraged the abnormal growth of β-Si3N4 grains, which allowed microstructural modification through control of the content and size distribution of β-Si3N4 nuclei. The mechanical response of different microstructures was characterized in terms of flexural strength, as well as indentation fracture resistance, at room temperature. The presence of even a small amount of abnormally grown β-Si3N4 grains improved the fracture toughness and minimized the variability in flexural strength.

Notes: A strong, wide infrared absorption band in 2050–2150-cm−1 range has been found in neutron-transmutation-doped silicon grown by the floating-zone method in a hydrogen atmosphere and annealed at 650 °C. This band is due to the stretching vibration of the Si–H bond, formed as hydrogen atoms diffuse, aggregate, and saturate silicon dangling bonds in the neutron-irradiation disordered region. This absorption band is similar to that of hydrogenated amorphous silicon in the 1900–2150-cm−1 range except that its vibration frequency is somewhat higher. The disordered region defect and its amorphous-siliconlike property could be observed because of the incorporation of hydrogen. The hydrogen concentration of the floating-zone melted silicon grown in a hydrogen atmosphere used in this study is estimated to be (1–2)×1017 cm−3 on the basis of the strength of this wide infrared absorption band. A possible reason for this vibration frequency shift is discussed.

Notes: The bi-Hamiltonian structure of the super KP hierarchy is obtained based on the even super KP operator Λ=θ2+∑i=−2∞Uiθ−i−1, as a supersymmetric extension of the ordinary KP bi-Hamiltonian structure. It is expected to give rise to a universal super W-algebra incorporating all known extended superconformal WN algebras by reduction. Also constructed is the super BKP hierarchy by imposing a set of anti-self-dual constraints on the super KP hierarchy.

Notes: This article is devoted to constructing a quantum version of the famous Kadomtsev–Petviashvili (KP) hierarchy by deforming its second Hamiltonian structure, namely, the nonlinear Wˆ∞ algebra. This is achieved by quantizing the conformal noncompact SL(2,R)k/U(1) coset model, in which Wˆ∞ appears as a hidden current algebra. For the quantum Wˆ∞ algebra at level k=1, an infinite set of commuting quantum charges in explicit and closed form was successfully constructed. Using them, a completely integrable quantum KP hierarchy is constructed in the Hamiltonian form. A two-boson realization of the quantum Wˆ∞ currents has played a crucial role in this exploration.

Notes: In this article the interrelationship between the integrable Kadomtsev–Petviashvili (KP) hierarchy, nonlinear Wˆ∞ algebra, and the conformal noncompact SL(2,R)/U(1) coset model at the classical level is studied. The Poisson brackets of the second Hamiltonian structure of the KP hierarchy is derived first explicitly, then the Wˆ1+∞ algebra and its reduction Wˆ∞ are defined. Then it is shown that the latter is realized in the SL(2,R)/U(1) coset model as a hidden current algebra, through a free field realization of Wˆ∞, in closed form for all higher-spin currents, in terms of two bosons. An immediate consequence is the existence of an infinite number of KP flows in the coset model, which preserve the Wˆ∞-current algebra.

Notes: The two-dimensional (2D) superstructure in the (001) plane of Bi-Sr-Ca-Cu-O superconductor was first proposed by Marshall et al. [Appl. Phys. Lett. 53, 426 (1989)]. Some results obtained in our experiments indicate that the apparent 2D superstructure modulation pattern results from two grains with a [001] twist boundary.

Notes: A digital procedure to estimate recharge/discharge rates that requires relatively short preparation time and uses readily available data was applied to a setting in central Wisconsin. The method requires only measurements of the water table, fluxes such as stream baseflows, bottom of the system, and hydraulic conductivity to delineate approximate recharge/discharge zones and to estimate rates. The method uses interpolation of the water table surface, recharge/discharge mapping, pattern recognition, and a parameter estimation model. The surface interpolator used is based on the theory of radial basis functions with thin-plate splines. The recharge/discharge mapping is based on a mass-balance calculation performed using MODFLOW. The results of the recharge/discharge mapping are critically dependent on the accuracy of the water table interpolation and the accuracy and number of water table measurements. The recharge pattern recognition is performed with the help of a graphical user interface (GUI) program based on several algorithms used in image processing. Pattern recognition is needed to identify the recharge/discharge zonations and zone the results of the mapping method. The parameter estimation program UCODE calculates the parameter values that provide a best fit between simulated heads and flows and calibration head-and-flow targets. A model of the Buena Vista Ground Water Basin in the Central Sand Plains of Wisconsin is used to demonstrate the procedure.

Notes: This paper investigates the synchronization of the intra-East Asian business cycles based on regional bilateral trade statistics. By evaluating three macroeconomic fundamentals: real GDP, industrial production, and unemployment, it is found that tighter intra-East Asian trade may most likely lead to more idiosyncratic business cycles and hence lower correlations of economic activity. When using regional trade as an international openness criterion in the theory of Optimum Currency Area, the finding suggests that for the immediate future, the creation of an East Asian monetary/currency union may not be feasible.

Notes: Two polytopic membrane proteins, NarK and NarU, are assumed to transport nitrite out of the Escherichia coli cytoplasm, but how nitrate enters enteric bacteria is unknown. We report the construction and use of four isogenic strains that lack nitrate reductase Z and the periplasmic nitrate reductase, but express all combinations of narK and narU. The active site of the only functional nitrate reductase, nitrate reductase A, is located in the cytoplasm, so nitrate reduction by these four strains is totally dependent upon a mechanism for importing nitrate. These strains were exploited to determine the roles of NarK and NarU in both nitrate and nitrite transport. Single mutants that lack either NarK or NarU were competent for nitrate-dependent anaerobic growth on a non-fermentable carbon source, glycerol. They transported and reduced nitrate almost as rapidly as the parental strain. In contrast, the narK–narU double mutant was defective in nitrate-dependent growth unless nitrate transport was facilitated by the nitrate ionophore, reduced benzyl viologen (BV). It was also unable to catalyse nitrate reduction in the presence of physiological electron donors. Synthesis of active nitrate reductase A and the cytoplasmic, NADH-dependent nitrite reductase were unaffected by the narK and narU mutations. The rate of nitrite reduction catalysed by the cytoplasmic, NADH-dependent nitrite reductase by the double mutant was almost as rapid as that of the NarK+-NarU+ strain, indicating that there is a mechanism for nitrite uptake by E. coli that is in-dependent of either NarK or NarU. The nir operon encodes a soluble, cytoplasmic nitrite reductase that catalyses NADH-dependent reduction of nitrite to ammonia. One additional component that contributes to nitrite uptake was shown to be NirC, the hydrophobic product of the third gene of the nir operon, which is predicted to be a polytopic membrane protein with six membrane-spanning helices. Deletion of both NarK and NirC decreased nitrite uptake and reduction to a basal rate that was fully restored by a single chromosomal copy of either narK or nirC. A multicopy plasmid encoding NarU complemented a narK mutation for nitrite excretion, but not for nitrite uptake. We conclude that, in contrast to NirC, which transports only nitrite, NarK and NarU provide alternative mechanisms for both nitrate and nitrite transport. However, NarU might selectively promote nitrite ex-cretion, not nitrite uptake.

Notes: Discusses the history, content and shortcomings of the 2003 Money Laundering Control Act of Taiwan, with two case studies involving money laundering (by the Yeh brother and Mr Chen, and by Mr Tzeng). Begins with the history of money laundering since Taiwan opened its financial markets in 1980, culminating in the 1996 Money Laundering Control Act, which was the first specific legislation of its type ever enacted by an Asian country. Details the provisions of the 2003 Act, including the requirements for financial institutions to ascertain clients' identities and to establish systems for detecting suspect financial transactions and preventing money laundering. Shows how the Money Laundering Prevention Center is enforcing the Act, how international cooperation is allowed for, and how institutions must operate Know Your Customer and Know Your Employee schemes. Indicates the need for still better regulations, and for improved training of financial institution employees so that the regulations can be effectively implemented.