The phase diagram of the extended anisotropic ferromagnetic-antiferromagnetic Heisenberg chain

By using Density Matrix Renormalization Group (DMRG) technique we study the phase diagram of 1D extended anisotropic Heisenberg model with ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor interactions. We analyze the static correlation functions for the spin operators both in- and out-of-plane and classify the zero-temperature phases by the range of their correlations. On clusters of $64,100,200,300$ sites with open boundary conditions we isolate the boundary effects and make finite-size scaling of our results. Apart from the ferromagnetic phase, we identify two gapless spin-fluid phases and two ones with massive excitations. Based on our phase diagram and on estimates for the coupling constants known from literature, we classify the ground states of several edge-sharing materials.Comment: 12 pages, 13 figure

Fabrication and parameters of a 1310-nm buried heterostructure operating in the microwave region

InGaAsP/InP nanoheterostructures have been grown by liquid phase epitaxy and their structural perfection has been studied. The nanoheterostructures have been used to fabricate buried mesa laser diodes on a p-InP substrate that emit in the spectral range 1310-1550 nm. The design of the buried mesa stripe diode with the use of a semi-insulating II-VI compound has made it possible to create laser diodes operating at a wavelength of 1310 nm with a telecommunication signal transfer rate of 5.5 GHz. The results are technologically attractive and reproducible. We analyze potentialities for further increasing the optical signal transfer rate. © 2013 Pleiades Publishing, Ltd

Fabrication and parameters of a 1310-nm buried heterostructure operating in the microwave region

InGaAsP/InP nanoheterostructures have been grown by liquid phase epitaxy and their structural perfection has been studied. The nanoheterostructures have been used to fabricate buried mesa laser diodes on a p-InP substrate that emit in the spectral range 1310-1550 nm. The design of the buried mesa stripe diode with the use of a semi-insulating II-VI compound has made it possible to create laser diodes operating at a wavelength of 1310 nm with a telecommunication signal transfer rate of 5.5 GHz. The results are technologically attractive and reproducible. We analyze potentialities for further increasing the optical signal transfer rate. © 2013 Pleiades Publishing, Ltd

Induction time in multi-fuels system. Effect of small additives of ozone and hydrogen peroxide on hydrogen-air detonation

Determination of induction time in multi-fuels combustible systems are discussed: using of global kinetic schema of elementary reactions and using of approximate equation for average reaction of induction time. Both types of data for induction time are used for prediction of detonation cell size and critical initiation energy for hydrogen-air mixtures with addition of ozone and hydrogen peroxide. The cell size was calculated with the help of Computer Program “SAFETY”. Calculated results are compared with experimental data. It is shown that small additives of ozone and hydrogen peroxide to hydrogen-air mixtures result in a shortening of the induction-zone length over the entire range of the initial H$_2$ concentrations. The comparative increase in the detonatability of the mixture in the presence of O$_3$ or H$_2$O$_2$ displays a substantially nonmonotonic nature

The role of optimal nutrition in the prevention of cardiovascular diseases

A balanced diet has always been part of a set of preventive measures with cardiovascular diseases (CVD). The aim of the research is to present relevant international data on the role of nutrients in reducing the risk of CVD. Results. This article discusses current data on the effect of consumption of saturated and unsaturated fatty acids, trans fats, cholesterol, dietary fiber, protein, edible salt potassium, magnesium and vitamins on the state of the cardiovascular system and the prevention of CVD. Recommendations on optimal nutrition are given to reduce cardiovascular risks, including those according to the new 3rd edition of the Guide to Cardiovascular Medicine (The ESC Textbook of Cardiovascular Medicine, 3 edn). Conclusion. When managing patients with cardiovascular diseases, it is necessary not only to take into account international nutritional recommendations, but also to focus the patient's attention on how to comply with them. Copyright© GEOTAR-Media Publishing Group

Synthesis of 3-alkyl-2, 4, 6-triphenylpyridines and 1,3-diphenyl-4- and-2-azafluorenes

The previously unknown 3-alkyl-2,4,6-triphenylpyridines were obtained from 1-methyl-3-alkyl-2, 6-diphenyl-4-piperidones. It was established that a mixture of 1,3-diphenyl-4-azafluorene and 1,3-diphenyl-2-azafluorene is formed in the dehydrocyclization of 3-methyl-2,4,6-triphenylpyridine. © 1976 Plenum Publishing Corporation