1, 3-dipolar cycloaddition of diazomethane to azolopyridazines. The synthesis of 8-methyl-8H- and 9-methyl-9H-pyrazolo[3, 4-d]-s-triazolo[4, 3-b]pyridazine and 1-methyl-1H- and 2-methyl-2H-imidazo[1, 2-b]pyrazolo[3, 4-b]pyridazine derivatives

The transformations of 7-methyl-7H- and 8-methyl-8H-pyrazolo[4, 3-d]tetrazolo[1, 5-b]pyridazines 1, 2, 9 and 10 into 8-methyl-8H- and 9-methyl-9H-pyrazolo[3, 4-H]-s-triazolo[4, 3-b]pyridazines 7 and 8 , and 1-methyl-1H-and 2-methyl-2H-imidazo[1, 2-b]pyrazolo[3, 4-d]pyridazines 13 and 14 are described.     

Electrochemical study of self-assembled monolayer adsorption

The electrochemical behaviour of self-assembled monolayer (SAM) of aliphatic hexadecanethiol was studied by cyclic voltammetry (CV), elimination voltammetry with linear scan (EVLS) and crystal quartz microbalance (QCM). SAMs were electrochemically created on gold-coated QCM crystal through the sulphur in 1-hexadecanethiol molecule head group. The effect of thiol concentration and potential scan rate on the SAM formation was studied. Formation of SAM was confirmed by CV and QCM. EVLS results revealed the kinetically controlled process followed with electrode reaction in adsorbed state characteristic for SAM formation at lower concentration. The electrode reaction of a totally adsorbed electroactive species was indicated by means of a peak-counter peak signal at higher thiol concentration.     

On the quadratic two-parameter eigenvalue problem and its linearization

We introduce the quadratic two-parameter eigenvalue problem and linearize it as a singular two-parameter eigenvalue problem. This, together with an example from model updating, shows the need for numerical methods for singular two-parameter eigenvalue problems and for a better understanding of such problems.There are various numerical methods for two-parameter eigenvalue problems, but only few for nonsingular ones. We present a method that can be applied to singular two-parameter eigenvalue problems including the linearization of the quadratic two-parameter eigenvalue problem. It is based on the staircase algorithm for the extraction of the common regular part of two singular matrix pencils.     

Synthesis and properties of 4,5‐dihydrobenzo[e]imidazo[2,1‐c][1,4,2]diazaphosphinine derivatives

A number of 4,5‐dihydrobenzo[e]imidazo[2,1‐c][1,4,2]diazaphosphinine derivatives were prepared by the direct phosphorylation of 1‐(4‐Chlorophenylcarboxamido)‐2‐(1H‐1‐imidazolyl)‐5‐trifluoromethylbenzene in basic medium with phosphorus(III) bromide and dibromophenylphosphine. The tricyclic compounds 6a, 6b , and 9 having a trivalent phosphorus atom undergo the diazaphosphinine ring opening upon treatment with secondary amines in the presence of sulfur. © 2002 John Wiley & Sons, Inc. Heteroatom Chem 13:84–92, 2002; DOI 10.1002/hc.10000     

On fundamental units of real quadratic fields of class number 1

Archiv der Mathematik - In this paper, we give a nontrivial lower bound for the fundamental unit of norm $$-1$$ of a real quadratic field of class number 1.     

On comparison theorems for elliptic inequalities

We obtain estimates for non-negative solutions of quasilinear elliptic inequalities with the lowest terms.     

A metaheuristic approach to solving a multiproduct EOQ-based inventory problem with storage space constraints

This paper considers the well-known static time-continuous multiproduct economic order quantity (EOQ) based inventory management problem with the storage space constraints. This problem is modelled as a combinatorial optimization problem in the corresponding dynamic discrete time system control process. In order to solve this problem approximately, we developed two heuristics: a special heuristic based on a local search technique and a metaheuristic procedure based on the variable neighbourhood search principle. The efficiency of two heuristics is preliminary examined and compared on several randomly generated instances with the same number of products.     

The Last Fortress of Tin's Tyranny – Protodenitration of Nitroalkanes

Protodenitration, a direct reduction of nitroalkanes to corresponding alkanes, already spans two centuries and is enabled by various reagents. This mini-review provides a historical development of the fundamental transformation and highlights the governing position of the Ono-Tanner reaction employing tributyltin hydride. Due to the unchallenged dominance of the toxic tributyltin hydride and environmentally unpopular solvents sharply contrasting with modern ecological trends, the current situation was dubbed “the last fortress of tin's tyranny.”     

Electricity consumption prediction using artificial intelligence

Central European Journal of Operations Research - The measurement of electricity consumption at 15-minute granularity, including for households, is increasingly mandated in the EU and this also...     

A statistical theory of polydisperse block copolymer systems under weak supercrystallization

A statistical theory of conjugated macro- and microphase separation in flexile polydisperse block copolymer systems with a given arbitrary molecular structural distribution is developed in the mean field approximation. A special attention is paid to recognizing and calculating all terms having the least order of magnitude to be taken into account. To this end a special procedure is elaborated enabling to distinguish between strongly and weakly fluctuating order parameters characterizing polydisperse systems and to construct explicitly a one-field parametrization of the free energy of the systems under investigation. The contribution of so-called higher harmonics and effect of a redistribution of macromolecules among coexisting phases are taken into account therewith by a proper renormalization of the fourth vertex of the corresponding effective hamiltonian. In order to compare the presented approach and other existing theories phase diagrams of molten polydisperse diblock copolymer are built numerically in approximations corresponding to different theories. It is shown that our rigorous approach results in phase diagrams qualitatively different from the conventional ones. In particular, we predict the existence of one-phase region having a quasicrystal symmetry and regions of coexistence of this phase with disordered phase and one having the symmetry of the body-centered-oubic lattice as well as a considerable shrinking of the region of the existence of the lamellar phase.