Synthesis,Structure, and Spectroscopic and Electrochemical Properties of Heteroleptic Bis(phthalocyaninato) Rare Earth Complexes with a C4 Symmetry

A series of eleven heteroleptic bis(phthalocyaninato) rare earth double‐deckers [M^III(pc){pc(α‐OC₅H₁₁)₄}] 1 – 11 (M=Y, Sm? Lu; pc=phthalocyaninato; pc(α‐OC₅H₁₁)₄=1,8,15,22‐tetrakis(1‐ethylpropoxy)phthalocyaninato) were prepared as racemic mixtures by [M^III(pc)(acac)]‐induced (acac=acetylacetonato) cyclic tetramerization of 3‐(1‐ethylpropoxy)phthalonitrile in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in refluxing pentanol. These compounds could also be prepared by treating [M^III(pc)(acac)] with the metal‐free phthalocyanine H₂{pc(α‐OC₅H₁₁)₄} in refluxing octanol. The whole series of double‐decker complexes 1 – 11 were characterized by elemental analysis and various spectroscopic methods. The molecular structures of the Sm, Eu, and Er complexes 1, 2 , and 8 , respectively, were also determined by single‐crystal X‐ray diffraction analysis. The effects of the rare earth ion size on the reaction yield, molecular structure, and spectroscopic and electrochemical properties of these complexes were systematically examined.     

Characterization of the graphs of the Johnson schemes G(3k, k) and G(3k + 1, k)

The graphs of the Johnson schemes G(3k, k) and G(3k + 1, k) are characterized by their parameters. In particular this finishes the characterization of the tetrahedral graphs G(n, 3).     

Multiple peak recordings in flow injection analysis

The quality and level of the information provided by conventional flow-injection systems can readily be enhanced by simple modifications. The different possibilities available for obtaining several peaks per injected sample are reviewed. Among the topics are simultaneous and sequential multidetection, multicomponent determinations (including speciation), reaction-rate methods, and automatic amplification of conventional analyte concentration ranges.     

Dynamical entropy of generalized quantum Markov chains

We compute the dynamical entropy in the sense of Connes, Narnhofer, and Thirring of shift automorphism of generalized quantum Markov chains as defined by Accardi and Frigerio. For any generalized quantum Markov chain defined via a finite set of conditional density amplitudes, we show that the dynamical entropy is equal to the mean entropy.Research supported in part by the Basic Science Research Program, Korean Ministry of Education, 1993–1994.     

Optical receiver design with high sensitivity and high dynamic range using feedback and lossy noise-matching network

A new type of optical receiver design providing high sensitivity and high dynamic range is presented that employs a lossy noise-matching network and feedback type amplifier. The design is based on the noise figure concept using the four noise parameters of FET, which makes it easy to design multigigabit opical receivers by combining it with microwave CAD tools. The effects of matching network element value and group delay variation of the preamplifier on receiver sensitivities are addressed. The predicted receiver sensitivity including the effect of group delay is -27.1 dBm, which is the highest sensitivity for a 10 Gbit s^-1 PIN-FET optical receiver reported to date.     

A Profit-maximizing Plant-loading Model with Demand Fill-rate Constraints

This paper discusses a new formulation of a class of plant product-mix loading problems which are characterized by capacitated production facilities, demand fill-rate requirements, fixed facility costs, concave variable production costs and an integrated network structure which encompasses inbound supply and outbound distribution flows. In particular, we are interested in assigning product lines and volumes to a set of capacitated plants under the demand fill-rate constraints. Fixed costs are incurred when a product line is assigned to a plant. The variable production-cost function also exhibits concavity with respect to each product-line volume. Thus both scale economies and plant focus effect are considered explicitly in the model. The model also can be used to determine which market to serve in order to best allocate the firm's resources. The problem formulation leads to a concave mixed-integer mathematical programme. Given the state of the art of non-linear programming techniques, it is often not possible to find global optima for reasonably sized problems. We develop an optimization algorithm within the framework of Benders' decomposition for the case of a piecewise linear concave cost function. Our algorithm generates optimal solutions efficiently.     

Application of ultrasound to organic reactions: ultrasonic catalysis on hydrolysis of carboxylic acid esters

Irradiation with ultrasound was found to facilitate the two-phase basic hydrolysis of aromatic carboxylic acid esters.