Tang W.,University of California at Los Angeles |
Tang W.,Los Alamos National Laboratory |
Picraux S.T.,Los Alamos National Laboratory |
Huang J.Y.,Sandia National Laboratories |
And 4 more authors.
Nano Letters | Year: 2013
At the nanoscale, defects can significantly impact phase transformation processes and change materials properties. The material nickel silicide has been the industry standard electrical contact of silicon microelectronics for decades and is a rich platform for scientific innovation at the conjunction of materials and electronics. Its formation in nanoscale silicon devices that employ high levels of strain, intentional, and unintentional twins or grain boundaries can be dramatically different from the commonly conceived bulk processes. Here, using in situ high-resolution transmission electron microscopy (HRTEM), we capture single events during heterogeneous nucleation and atomic layer reaction of nickel silicide at various crystalline boundaries in Si nanochannels for the first time. We show through systematic experiments and analytical modeling that unlike other typical face-centered cubic materials such as copper or silicon the twin defects in NiSi2 have high interfacial energies. We observe that these twin defects dramatically change the behavior of new phase nucleation and can have direct implications for ultrascaled devices that are prone to defects or may utilize them to improve device performance. © 2013 American Chemical Society.
Bondarchuk S.V.,Cherkasy National University |
Minaev B.F.,KTH Royal Institute of Technology
Chemical Physics | Year: 2011
Density functional theory (DFT) calculations of several 2-X-substituted phenyl cations (X = 2-CHO, 2-CH2OH, 2-CHS, 2-CHNH, 2-OCHNH, 2-SCHNH, 2-CHCH-CHCH2, 2-CHCH2 and 2-NO2) have been carried out in the gas phase and in acetonitrile (MeCN) at the B3LYP/6-31G(d,p) level of theory. The stationary point geometry of these aryl cations have been found to be in strong dependency of the medium. In the gas phase, unexpected behavior of considered aryl cations takes place resulting in the rearrangement or ring closure reaction. Such the cyclization reaction is proceeding via the nearby atom of the substituent which appears in relative vicinity (up to ∼3 ) to the cationic center. Only in the case of 2-NO2 derivative, the geometry optimization has lead to rearranged quazi-quinoid structure of the cation that, obviously, takes place because of instability of the ring formed. Scan of the potential energy surface (PES) of 2-nitrophenyl cation has displayed no any reaction path leading toward the rearranged structure. Thus, the impossibility of existing of the singlet state of 2-nitrophenyl cation in the gas phase has been offered. The singlet-triplet transition of 2-nitrophenyl cation has been discussed in terms of the spin-orbit coupling (SOC) effects. © 2011 Elsevier B.V. All rights reserved.
Vasylyshyna E.,Cherkasy National University
Acta Scientiarum Polonorum, Technologia Alimentaria | Year: 2016
Background: Cherries are a valuable dietary raw material and possess medicinal properties. Considering the nutritional, medical and vitamin value of cherry fruits, the purpose of this research was to produce a scientific justification for preserving the quality of cherry fruits using different freezing methods. Material and methods: To do this, cherr y fruits from the Lotovka (Cerasus vulgaris) variety were frozen in various ways: packed in polyethylene bags (control); previously suspended in a 20% sugar solution and packing frozen cherry in polyethylene bags; suspended in a 20% sugar solution with the addition of 4% ascorutin and frozen followed by pre-packaging in polyethylene bags; cherry fruits were frozen in a 20% sugar solution in plastic cups of 0.25 cm3; they were also frozen in a 20% sugar solution with the addition of 4% ascorutin in plastic cups. The frozen products were stored at a temperature not higher than -18°C for up to 6 months. Result: Studies have shown the appropriateness of freezing cherry fruits, particularly in a 20% sugar solution with the addition of 4% ascorutin. The advantages of these fruits are in ascorbic acid preservation in 1.5 times and reduction of tanning and coloring substances only by 27%, soluble solids to 7%, sugars - 4%, acids - 12%, in tasting evaluation of 5 points. Conclusions: Frozen cherry fruits in a 20% sugar solution with the addition of 4% ascorutin can be used in dietary nutrition for patients with cardiovascular diseases. © Wydawnictwo Uniwersytetu Przyrodniczego w Poznaniu.
Mudrak R.,Cherkasy National University
Economic Annals-XXI | Year: 2014
The presence of food security at the macro level does not guarantee food security at the micro level. This creates a serious management problem - how to ensure food safety at all levels of the national economy. The aim of the paper is to investigate the influence factors of consumer behaviour in his household's food security and to develop proposals to neutralize the individual factors of food insecurity. Pressing social and economic problem in Ukraine is non-rational consumer behaviour of households. The most telling example is expenditure on food items that do not represent the nutritional value and are harmful to health - alcohol and tobacco. The share of cash expenditures on alcohol in the poorest I, II and III decile groups no less than the share of cash expenditures in V decile group. The share of cash expenditures on tobacco increases over the reduction of average income. One of the main causes of the food insecurity is excessive income differentiation, diverse popularization and promotion of prestigious consumption patterns in the media. Low levels of gastronomic culture and lack of basic knowledge of many Ukrainian domestic households also are destructive factors of safe and quality nutrition. This study leads to the following conclusions and suggestions: 1) the national food security and food security of individual households differ in their object of research methods and influence factors evaluation; 2) the household food security depends on the model of consumer behaviour; 3) the spending pattern of the households is formed under the influence of the surrounding social environment; 4) consumer behaviour of the domestic households is non-rational because of: a) in the Ukrainian social environment wealthy households formed costly, prestigious model of consumer behaviour, being actively propagated by the media. The poor households fall into the psychological trap of inferiority complex and looking out from it by copying consumer behaviour of the wealthy households; b) low level of gastronomic culture; c) the lack of full information to consumers. In order to partially neutralize the effect of the negative factors that cause irrational consumer behaviour of the households, it is necessary to apply a set of measures. In particular: 1) solving behavioural problems should be connected with the approval of the ruling middle class; 2) using of educational and outreach activities designed to promote public awareness of rejection and condemnation of arrogance material possessions is essential; 3) creation of educational awareness campaign should be worked out aimed at gastronomic culture raising and consumer education of the households. Management measures development to implement such proposals is a promising direction for further research. © 2014 Institute of Society Transformation.
Minaev B.F.,Cherkasy National University |
Minaev B.F.,KTH Royal Institute of Technology |
Baryshnikov G.V.,Cherkasy National University |
Minaeva V.A.,Cherkasy National University
Dyes and Pigments | Year: 2012
The recently synthesized high-performance triarylamine dyes with the dithienosilole π-conjugated spacer for efficient organic solar cells are calculated at the density functional theory (DFT) level with the Bader approach for the quantum theory of atoms in molecule (QTAIM) analysis. The presence of stabilizing intramolecular hydrogen bonds and Van der Waals interactions in the dye molecules is predicted and the energies of these interactions are estimated. The electronic bands nature in absorption spectra of the dyes is determined by the time-dependent DFT calculations with a linear response methodology using B3LYP and BMK hybrid functionals. Relations between incident light absorption intensity in the first long-wavelength band of the dye, its polarization, HOMO-LUMO orbital nature and the driving force of electron injection to the semiconductor are discussed. © 2011 Elsevier Ltd. All rights reserved.