Three-port electrical and optical model for LiTaO3 electro-optic probe with CPW test structure

A three-port electrical and optical model of LiTaO₃ probes with a high-bandwidth coplanar waveguide (CPW) test structure is developed in this paper. The three-port model is constructed by combining the full wave field simulation and the neural network techniques. The three-port model has the same accuracy as the full wave modeling, but its characteristics are directly obtained from the neural network weighting parameters rather than the complicated full wave simulation. With this model, both invasiveness and waveform distortion in the external E-O sampling can be de-embedded.     

The singlet oxygen and carotenoid interaction.

Second-order rate constants kQ for the quenching of O2(1 delta g) by carotenoids were determined at room temperature in benzene and toluene using the technique of time-resolved luminescence. Of the C40 pigments studied, lycopene was found to be the most efficient quencher, but the increased efficiency compared with all-trans beta-carotene was less than previously reported. The efficiency of quenching of O2(1 delta g) was extended to a number of solvents with varying viscosities. kQ was found to be inversely proportional to solvent viscosity, although the relationship is not simply linear. The results suggest the involvement of thermodynamic factors. The efficiency of deactivation of O2(1 delta g) was found to increase with the number of conjugated carbon-carbon double bonds, i.e. kQ(C60) greater than kQ(C50) greater than kQ(C40). A number of xanthophylls were included in this study; it would appear that an epoxide group rather than carbonyl or hydroxyl substituents increase the reactivity of the carotenoid with respect to O2(1 delta g).     

Discontinuous piecewise linear optimization

A theoretical framework and a practical algorithm are presented to solve discontinuous piecewise linear optimization problems dealing with functions for which theridges are known. A penalty approach allows one to consider such problems subject to a wide range of constraints involving piecewise linear functions. Although the theory is expounded in detail in the special case of discontinuous piecewiselinear functions, it is straightforwardly extendable, using standard nonlinear programming techniques, tononlinear (discontinuous piecewise differentiable) functions.The descent algorithm which is elaborated uses active-set and projected gradient approaches. It is a generalization of the ideas used by Conn to deal with nonsmoothness in thel ₁ exact penalty function, and it is based on the notion ofdecomposition of a function into a smooth and a nonsmooth part. The constrained case is reduced to the unconstrained minimization of a (piecewise linear)l ₁ exact penalty function. We also discuss how the algorithm is modified when it encounters degenerate points. Preliminary numerical results are presented: the algorithm is applied to discontinuous optimization problems from models in industrial engineering. © 1998 The Mathematical Programming Society, Inc. Published by Elsevier Science B.V.Supported by the Natural Sciences and Engineering Council of Canada and the Centre de Recherches Mathématiques, Université de Montréal.This research was supported in part by the Advanced Research Projects Agency of the Department of Defense and was monitored by the Air Force Office of Scientific Research under Contract No. F49620-91-C-0079. The United States Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation hereon.     

The automotive system — a complex coupling of matter and energy networks

Linear equations are shown with schematic diagrams which together describe the automotive dynamic model. However, the principal intent of the paper is not to study the dynamics of automotive operations. The schematic diagrams of each sub-system are presented to indicate the possible points of energy storage and dissipation and how they relate to the continuity of energy.From the sub-system diagrams it is now possible to generate energy and matter balances for the automotive system. The final energie matrix expression (eqn 49), which relates to all components of the system, is developed.     

Chemically-enabled synthesis of 1,2,3,4-tetrahydroisoquinolin-1-ones

We have developed a number of efficient protocols for the facile synthesis of 1,2,3,4-tetrahydroisoquinolin-1-ones. This synthetic methodology allowed concise and efficient exploration of the SAR in all areas of the molecule. A number of these methods proved to be versatile, efficient and amenable to parallel synthesis.     

Untersuchung von Milch und Milchprodukten

Ohne Zusammenfassung     

Nonionic diethanolamide amphiphiles with saturated hydrocarbon chains: Neat crystalline and lyotropic liquid crystalline phase behavior

The solid state and lyotropic phase behavior of a series of nonionic diethanolamide amphiphiles with increasing saturated hydrocarbon chain length (lauroyl, myristoyl, palmitoyl, and stearoyl) has been examined. All four saturated diethanolamide amphiphiles form a crystalline solid with two or three different polymorphic crystalline forms at room temperature. Melting points and associated enthalpies for these four amphiphiles increased with increasing chain length. Approximate partial binary phase diagrams have been constructed for each amphiphile/water system by combining Cross-Polarized Optical Microscopy (POM) and Small-Angle X-ray Scattering (SAXS) results. In the presence of water, all four diethanolamides form an L(α) phase, between 10% and 50% water content, and an L(2) phase with decreasing hydration and increasing temperature. In addition to the L(α) and L(2) phases, the shorter chain diethanolamide amphiphiles (lauroyl and myristoyl) also display a normal micellar phase (L(1)) at higher water contents, occurring to lower temperatures than the L(α) phase. By examining the effect of subtle molecular changes on both neat and lyotropic phase behavior, amphiphiles can be designed with properties tailored to a desired application.     

Diffusion and segregation of niobium in fcc-nickel

Niobium is one of the major alloying elements, among the refractory elements, contributing to the strengthening of superalloys. Consequently, data about its behavior and its migration mechanism in fcc-Ni are essential knowledge to understand and control the strengthening in such alloys. We present in this work Nb interactions, solubility and diffusion in Ni performed by using the GGA approximation of the density functional theory. The substituted site is found to be the most favorable configuration in comparison to the tetrahedral and octahedral sites. The effect of temperature on solubility is discussed taking into account the thermal expansion of the lattice parameter and the vibrational contribution. Its diffusion mechanism is also discussed and compared to the literature. We finally discuss the segregation of Nb atoms on a Σ(5)-(012) symmetric tilt grain boundary.