Molecular crystal structure and chemical properties of 4-phenyl-3,5-diethoxycarbonyl-1,2,6-trimethyl-1,2-dihydropyridine

The molecular crystal structure of 4-phenyl-3,5-diethoxycarbonyl-1,2,6-trimethyl-1,2-dihydropyridine has been investigated by x-ray structural analysis. The three-dimensional structural properties of the molecule have been compared against the large observed reactivity of the 3-ethoxycarbonyl group with respect to nucleophilic substitution reactions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1236–1239, September, 1991.     

Characteristics of thermoradiative destruction of BaS2O6·2H2O

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 4, pp. 613–618, October, 1991.     

Fourier-Galerkin numerical technique for solitary waves of fifth order Korteweg-de Vries equation

The present paper is aimed to display the performance of the Fourier-Galerkin technique developed earlier by the authors for numerical treatment of localized solutions in ²(-∞, ∞) for higher-order equations. The solitary-wave solution of the Kortweg-de Vries fifth order equation is obtained numerically and compared with approximate results of other authors.     

Galois extensions as functors of comodules

Let A be a finite Hopf algebra over a commutative ring k. We show a one-to-one correspondence between the A-Galois extensions of k and certain functors from the category of A-comodules to the category of k-modules.     

Total synthesis of malayamycin A and analogues

The total synthesis of the bicyclic C-nucleoside malayamycin A is described starting with d-ribonolactone. A new method was developed to obtain preparatively important quantities of β-pseudouridine, which was used as an intermediate. The synthesis of a carba N-nucleoside analogue of malayamycin A is also described.     

A Hybrid Multiobjective Evolutionary Algorithm for Solving Vehicle Routing Problem with Time Windows

Vehicle routing problem with time windows (VRPTW) involves the routing of a set of vehicles with limited capacity from a central depot to a set of geographically dispersed customers with known demands and predefined time windows. The problem is solved by optimizing routes for the vehicles so as to meet all given constraints as well as to minimize the objectives of traveling distance and number of vehicles. This paper proposes a hybrid multiobjective evolutionary algorithm (HMOEA) that incorporates various heuristics for local exploitation in the evolutionary search and the concept of Pareto's optimality for solving multiobjective optimization in VRPTW. The proposed HMOEA is featured with specialized genetic operators and variable-length chromosome representation to accommodate the sequence-oriented optimization in VRPTW. Unlike existing VRPTW approaches that often aggregate multiple criteria and constraints into a compromise function, the proposed HMOEA optimizes all routing constraints and objectives simultaneously, which improves the routing solutions in many aspects, such as lower routing cost, wider scattering area and better convergence trace. The HMOEA is applied to solve the benchmark Solomon's 56 VRPTW 100-customer instances, which yields 20 routing solutions better than or competitive as compared to the best solutions published in literature.     

The high-T c superconductor Sr0.2Lai1.8CuO4: A direct and inverse-photoemission study

We have measured ultraviolet and inverse-photoemission spectra of the novel superconductor Sr₀₂La_1.8CuO₄. Our results compare favorably with recent band-structure calculations for La₂CuO₄.A full account of this work will be published elsewhere [1]