Natural convection mass transfer behavior of serially connected cylindrical electrodes

Natural convection mass transfer rates at both vertical and horizontal serially connected tubes were reported using the electrochemical technique involving the measurement of limiting currents for the deposition of copper on copper cylinders from acidified cupric sulphate solutions. Measurements were carried out with: (a) one tube active; (b) two tube surfaces active; (c) three tube surfaces active.

The electrolyte concentration and a number of serial connections of tubes were varied to provide a range of GrSc extending from 5.3×10⁸ to 9.5×10¹¹. The mass transfer rates at serially connected horizontal cylinders were in good agreement with mass transfer data in the literature. Correlation of results covered both laminar and turbulent conditions separately. The mass transfer rates at serially connected vertical cylinders were controlled by the boundary layer development at the multi-electrodes. The results for vertical electrodes, which are single, serially connected two and three electrodes, were separately correlated in the turbulent region.

The results illustrate the important effect of boundary layer development in determining current distribution in multi-electrode electrochemical cells.     

伏安法测量电阻的误差分析

本文给出伏安法测量电阻时，安培计内、外接法的定量选择公式，定量地描绘了使测量误差在允许范围所需要采取的具体措施。     

A Covariant Poisson Deformation Quantization with Separation of Variables up to the Third Order

We give a simple formula for the operator C ₃ of the standard deformation quantization with separation of variables on a Kähler manifold M. Unlike C ₁ and C ₂, this operator cannot be expressed in terms of the Kähler–Poisson tensor on M. We modify C ₃ to obtain a covariant deformation quantization with separation of variables up to the third order which is expressed in terms of the Poisson tensor on M and can thus be defined on an arbitrary complex manifold endowed with a Poisson bivector field of type (1,1).     

Stochastic analyses of the dynamics of generalized Little-Hopfield-Hemmen type neural networks

Stochastic analyses are conducted of model neural networks of the generalized Little-Hopfield-Hemmen type, in which the synaptic connections with linearly embeddedp sets of patterns are free of symmetric ones, and a Glauber dynamics of a Markovian type is assumed. Two kinds of approaches are taken to study the stochastic dynamical behavior of the network system. First, by developing the method of the nonlinear master equation in the thermodynamic limitN, an exact self-consistent equation is derived for the time evolultion of the pattern overlaps which play the role of the order parameters of the system. The self-consistent equation is shown to describe almost completely the macroscopic dynamical behavior of the network system. Second, conducting the system-size expansion of the master equation for theN-body probability distribution of the Glauber dynamics makes it possible to analyze the fluctuations. In the course of the analysis, the self-consistent equation for the pattern overlaps is derived again. The main result of the rigorous fluctuation analysis is that as far as the fluctuations are concerned, the time course of the pattern overlap fluctuations behaves independently of the fluctuations in the remaining modes of the system's macrovariables, in accordance with the self-determining property of the macroscopic motion of the pattern overlaps for neural networks with linear synaptic couplings.     

Epoxy casting resins with improved electrical conductivity

Summary It is reported on chemical modification of epoxy resins in order to enhance electricaldc-conductivity from 10^–18 S/cm to 10^–13 S/cm. Two methods of solution have been committed. The first method is based on semiconducting organic model substances having chemical structure similar to bisphenol A based epoxy resins. Substituting the hardener partially by pyromelitic acid anhydride (PMDA) and applying-Al₂O₃ as dehydration catalyst and as lean material a resin with modified connection structure was synthesized. In this way the conductivity attained the wanted level but reproducibility was unsufficient. In the second method of modification the surface of the lean material -A₂O₃ was coated by tetracyanoethylene (TCNE) to form a charge transfer complex before it was incorporated into the epoxy resin. An essential enhancement of conductivity was only obtained for temperatures > 60 °C. It is probably that the Al₂O₃ content (66 wt.-%) is not yet sufficient to enable charge carrier transport throughout the whole sample, because the grains of lean material have no sufficient contact with one another.

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Zusammenfassung Epoxidharze wurden chemisch modifiziert, um die Gleichstromleitfähigkeit von 10^–18 S/cm auf 10^–13 S/cm zu verbessern. Es wurden zwei Methoden angewendet. Der erste Weg beruht auf halbleitenden organischen Modellsubstanzen mit Strukturen ähnlich der des Epoxidharzes. Teilweises Substituieren des Härters durch Pyromellitsäureanhydrid (PMDA) sowie Verwendung von-Al₂O₃ als Katalysator für Dehydration und als Magermittel führten zu einem Epoxidharz mit modifizierter Verknüpfungsstruktur. Die Leitfähigkeit erreichte zwar den gewünschten Wert, jedoch war die Reproduzierbarkeit ungenügend. Bei der zweiten Methode wurde die Oberfläche des Magermittels-Al₂O₃ vor der Einbettung in das Epoxidharz mit Tetracyanoäthylen (TCNE) beschichtet zwecks Bildung eines Charge Transfer Komplexes. Eine wesentliche Verbesserung der Leitfähigkeit war nur für Temperaturen > 60 °C festzustellen. Wahrscheinlich ist der Al₂O₃-Anteil (66 Gew.-%) noch nicht ausreichend um Ladungsträgertransport zu ermöglichen, weil nicht genügend Körner des Magermittels miteinander in Kontakt kommen.

     

膜电极上并联电容和控制电流示波电位滴定法

本文研制了几种含聚氯乙烯（ＰＶＣ）膜的选择性电极，使用两种克服电极上交流噪音的方法即并联电容和控制电流示波电位滴定法测定Ｃｕ＾２＋、Ｎｉ＾２＋等金属离子以及ＴＰＢ＾－、Ｍｎｏ４等阴离子并对盐酸左旋咪唑，盐酸阿米替林，心得安等药物含量进行了测定，文中还对这两种方法消除交流噪音的机理进行了探讨，获得满意的结果。     

The energy well connection graph: a use of curvilinear coordinates to achieve dimension reduction for graph representation of molecular conformation energy data

In the conformation space of a flexible molecule, curvilinear coordinate paths connecting conformations of segments of the given molecule are used to reduce the number of variables required for describing barriers between preferred conformations of the molecule as a whole. The technique is applied to a hypothetical example, then to m-trinuoromethyl-N-ethyl-amphetamine (fenfluramine), and to N-methyl-3-phenyl-3-(o-methoxyphenoxy)-propylamine (nisoxetine). In the latter example, the number of variables is thus reduced from six to three. In all three examples, a graph representation of low-energy well connection is achieved. The limit of easy comprehension has thus been moved back from about three torsion angles to three effective segments. Within this limit the procedure leads to a quantitative diagram, which is no harder to read than a contour map, showing the barriers to low-energy interconnection among the favorable conformations of a moderately complex molecule.     

Effect of channel connection on flow and salinity distribution of Danshuei River estuary

Numerical models are often used to evaluate the potential impact of human alteration of natural water bodies and to help the design the alternation to mitigate its impacts. A vertical (laterally integrated) two-dimensional hydrodynamic model was expanded to include the capability of simulating river loops as well as tributaries. The model was performed and applied to the Danshuei River estuarine system in northern Taiwan which consists of three major tributaries: the Tahan Stream, Hsintien Stream, Keelung River, and one river loop under the Chung-Hsin Bridge. The expanded model was reverified with observational field data of 2000. The verified model was then used to hindcast the river hydrodynamic conditions with a loop connection between the Danshuei River and Keelung River, which existed prior to 1965. It was found that the configuration of river loop connection has significant impacts on the residual transport along the connecting channel and the salinities in the connected river branches. The results show that the model may provide an ideal tool for management decision.     

Special polynomials in free framed Lie algebra

A framed Lie algebra is an algebra with two operations which is a Lie algebra with respect to one of these operations. A basic example is a Lie algebra of vector fields on a manifold with connection where the covariant derivative serves as an additional operation. In a free framed Lie algebra, we distinguish a set of special polynomials that geometrically correspond to invariantly defined tensors. A necessary condition of being special is derived, and we presume that this condition is also sufficient. Translated from Algebra i Logika, Vol. 47, No. 5, pp. 571–583, September–October, 2008.