Search results for "TOPOLOGY"

ChemInform Abstract: o-(Hydroxyalkyl)phenyl P-Chirogenic Phosphines as Functional Chiral Lewis Bases.

2013

The stereoselective synthesis of P-chirogenic phosphines bearing an o-hydroxyalkyl chain is described.

1986

Etude de deux systemes differents avec de l'hydroxy-4 benzoate de phenyle comme unite mesogene. Les separateurs sont formes de 6 unites methylene et le squelette est de l'acide poly(meth)acrylique

Application of the fuzzy TOPSIS method in management of food supply chain

2020

ChemInform Abstract: A Series of Calix(4)arenes, Having Two Opposite Para Positions Connected by an Aliphatic Chain.

1989

A Simulation Model of a Tandem Coordinated Supply Chain

2010

This paper presents a study of a coordinated production inventory-system. In the proposed model, any echelon considers its successors as part of its inventory system and generates the replenishment order on the basis of operational information of its partners. We show that the coordinated decision making allows elimination of information distortion along the chain. Furthermore, we show how the bottom-up transmission of inefficiencies, typical of traditional supply chains, is avoided.

Local symmetries of digital contours from their chain codes

1996

In this work symmetry is evaluated as a numeric feature for each point of a contour, using only the positions of a local vicinity of points. A measurement is defined, named as Local Symmetric Deficiency (LSD), so that the lower this quantity is, the higher the symmetry will be in the local region considered. This approach is very simple and it is based on a suitable manipulation of the chain code of the curve. Its computational cost is very low and it has the advantages of a parallel algorithm, since values for LSD can be computed for each point independently.

A rare example of nickel(ii) chains based on a heteroscorpionate-like ligand with quadruple imidazolyl interactions

2014

The first nickel(ii) complex with the heteroscorpionate-like bridging ligand DIMMAL (2-di1H-2-imidazolylmethylmalonate), [Ni(DIMMAL)(H2O)3]n·3nH2O (1), is a one-dimensional coordination polymer whose structure shows regular Ni(ii) chains with H-bonding inter-chain interactions and a rare example of a Quadruple Imidazolyl Embrace (QIE). The Ni(ii) chain shows a weak antiferromagnetic interaction that can be modelled with a regular S = 1 chain model including a zero field splitting with g = 2.270, J = -1.5 cm(-1) and D = -2.26 cm(-1).

Current views on the mechanism of catalytic cracking

2000

Abstract The cracking mechanisms of hydrocarbons have been reviewed and the kinetic and thermodynamic implications of the different steps, i.e. initiation, chain propagation, and termination, have been discussed. Although the cracking mechanism of olefins and alkylaromatics is well established, the initiation step for the cracking of paraffins is still under debate. The role of Bronsted-type active sites and also the possible influence of extra-framework Al species in the case of zeolite catalysts, especially when commercial feeds and industrial conditions are employed, are presented. The product distribution is determined by the number of propagation events occurring per initiation step, a…

Crystal structure and magnetic properties of Cu(TIM)CuBr4: An alternating site-alternating exchange chain system

2007

Abstract The title compound, Cu(TIM)CuBr4 (where TIM is a macrocycle ligand) is a member of the Cu(TIM)MX4 family, which contains linear chain structures with ⋯ Cu ⋯ X – M – X ⋯ Cu ⋯ X – M - ⋯ linkages. This chain structure defines an alternating exchange/alternating site 1d system. For M=Cu, alternating FM/AFM chains are formed with JFM>| JAFM|. Structural and magnetic data are presented, along with an analysis of the exchange pathways.

On the Performance of Channel Assembling and Fragmentation in Cognitive Radio Networks

2014

[EN] Flexible channel allocation may be applied to multi-channel cognitive radio networks (CRNs) through either channel assembling (CA) or channel fragmentation (CF). While CA allows one secondary user (SU) occupy multiple channels when primary users (PUs) are absent, CF provides finer granularity for channel occupancy by allocating a portion of one channel to an SU flow. In this paper, we investigate the impact of CF together with CA for SU flows by proposing a channel access strategy which activates both CF and CA and correspondingly evaluating its performance. In addition, we also consider a novel scenario where CA is enabled for PU flows. The performance evaluation is conducted based on…