APPROXIMATION OF IMPLICITLY EXPRESSED OPTIMALITY CRITERIA BY POZYNOM AND ANALYSIS OF THEIR SENSITIVITY

Authors consider the possibility and feasibility of a given tabular function approximation by pozynom. Authors have shown that if the function is approximated by binomial pozynom, the solution of direct and inverse problems of sensitivity is obtained in an analytical form

A DFT Study on Electronic and Structural Properties of Graphene Nanoribbons

We carry out quantum chemistry calculations on armchair graphene nanoribbons (AGNRs) using density-functional theory. PVE/SVP results for the dependence of energies of the highest occupied (HOMO) and lowest unoccupied molecular orbitals (LUMO) as well as energy gaps on AGNR widths and lengths are presented. We compare the HOMO and LUMO energies of a series of AGNRs with those energies of fullerene C60 and its soluble derivative, PCBM, to ascertain whether it is possible to use such AGNRs as electron acceptors in organic solar cells. The influence of Stone-Wales defects embedded in the frameworks of AGNRs on their electronic properties is also studied

DFT Study on Structural and Mechanical Properties of Single-walled Carbon and Boron Nitride Nanotubes Functionalized with Carbenes

This paper presents quantum chemistry study on structural and mechanical properties of a series of single-walled carbon nanotubes (SWCNTs) and boron nitride nanotubes (BNNTs) functionalized with carbenes. At the PBE/SVP level, the obtained data on pristine nanotubes are in good accordance with the results of previous experimental and theoretical studies. The calculations show that carbenes functionalization, in general, distorts both SWNCTs and BNNTs frameworks, but there exists the difference between ‘axial’ and ‘circumferential’ functionalization. It turns out that in both cases elastic properties diminish with increasing concentration of adsorbents, however, the functionalized SWCNTs and BNNTs remain strong enough to be suitable for reinforcement of composites

Structural and Mechanical Properties of Fluorinated SWCNTs: a DFT Study

This paper presents a study on structural and mechanical properties of a series of fluorinated armchair single-walled carbon nanotubes (SWCNTs) by using density functional theory. At the PBE / SVP level, the data obtained compare well with experimental and theoretical studies. The results show that fluorination, in general, distort SWNCTs framework, but there exists the difference between ‘axial’ and ‘circumferential’ functionalization. It turns out that elastic properties diminish with increasing concentration of adsorbents, however, the fluorinated SWCNTs remain strong enough to be suitable for reinforcement of composites

Budget management in the system of solving ecological contradictions of development of the national economy: territorial approach

The article analyses organisational and economic factors and forms a theoretical and methodical approach to budget management in the system of solving ecological contradictions of development of territorial systems of the national economy. The article justifies improvement of processes of managing budgets, directed at overcoming ecological contradictions, on the basis of conceptual provisions of the budgeting oriented at the result. It develops a scheme-model of the organisational and structural solution of ecological contradictions, with reinforcement of the integration role of the budgeting method, in the system of managing an administrative and territorial unit using example of the Sumy oblast. The offered theoretical and methodical approach to improvement of the budget management in the territorial and economic system allows development of principles of the on trust management in the field of ecological and economic relations and also activation of practical introduction of managerial instruments of consensual solution of ecologically caused conflict situations with application of specialised management-consulting activity

DFT Study on Adiabatic and Vertical Ionization Potentials of Graphene Sheets

Adiabatic and vertical ionization potentials (IPs) of finite-size graphene sheets as a function of size were determined by using density functional theory. In the case of graphene a very moderate gap between vertical and adiabatic IPs was observed, whereas for coronene molecule as a model compound these values differ considerably. The ionization process induces large changes in the structure of the studied sheets of graphene; “horizontal” and “vertical” bond lengths have different patterns of alternation. It was also established that the HOMO electron density distribution in the neutral graphene sheet affects its size upon ionization. The evolution of IPs of graphene sheets towards their work functions was discussed

Supercooling during crystallization of fusible metal particles in multilayer “carbon-metal-carbon” films

Ссылка на статью на русском языке: Петрушенко С.И., Дукаров С.В., Сухов В.Н. Переохлаждение при кристаллизации частиц легкоплавких металлов в многослойных пленках «углерод-металл-углерод» // Вопросы атомной науки и техники. Серия: Физика радиационных повреждений и радиационное материаловедение №4(104), 2016. стр. 118-124The results of studies of phase melting-crystallization transitions in thin films of fusible metals between thicker layers of amorphous carbon are given. It has been found that, due to poor wetting in contact systems under study, thin layers of fusible metals decompose into separate islands while first heated. Such films are a model of the system “fusible particles in the refractory matrix”. Using two independent in situ techniques (electrical resistance measuring and electron-diffraction studies during heating and cooling) values of supercooling during crystallization of liquid phase nanoparticles in multilayer C-Bi-C, C-Pb-C, C-Sn-C films, equal to 115, 135 and 160 K, respectively have been obtained. - - - - - - - - - - - Приводятся результаты исследований фазовых переходов плавлениекристаллизация в тонких пленках легкоплавких металлов, находящихся между более толстыми слоями аморфного углерода. Установлено, что вследствие плохого смачивания в исследуемых контактных системах уже при первом нагреве тонкие слои легкоплавких металлов распадаются на отдельные островки. Такие пленки представляют собой модель системы «легкоплавкие частицы в тугоплавкой матрице». С помощью двух независимых in situ методик (измерения электросопротивления и электронографических исследований в процессе нагрева и охлаждения) получены величины переохлаждения при кристаллизации наночастиц жидкой фазы в многослойных пленках (C-Bi-C, C-Pb-C, C-Sn-C), равные 115, 135 и 160 K соответственно

Radiofrequency ablation for treatment of varicose veins of lower limbs

Catedra chirurgie 1, Universitatea Naţională de Medicină „N.Pirogov”, Vinniţa, Ucraina, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Venele varicoase ale extremităţilor inferioare sunt frecvent întîlnite în populaţia ţărilor occidentale industrial dezvoltate afectînd 10-15% de bărbaţi şi 20-25% de femei. Această prevalenţă înaltă este responsabilă pentru costuri sociale şi medicale majore. Scopul studiului a fost evaluarea rezultatului clinic al tratamentului chirurgical prin ablaţie cu radiofrecvenţă (RFA) la bolnavii cu varice ale membrelor inferioare. Material şi metode: O sută patruzeci şi doi de bolnavi cu vene varicoase au fost supuşi RFA al segmentului proximal de venă safenă magna cu ajutorul dispozitivului “VNUS Closure”™. Diametrul venei a variat între 5 şi 20 mm. Cateterul pentru RFA a fost introdus prin puncţie percutană sau o incizie cutanată minimă. Toate intervenţiile au fost realizate sub anestezia locală infiltrativă cu ghidaj ultrasonor. Au fost studiate schimbările morfologice la nivelul peretelui venei safene magna supuse tratamentului prin RFA.Rezultate: Profunzimea necrozei a fost determinată la nivelul stratului endotelial şi subendotelial cu detaşarea caracteristică a acestora, cu colabarea şi îngustarea lumenului vascular. Specificul particular reprezintă lipsa fenomenului de neoangiogeneză la nivelul joncţiunii safenofemurale şi safenopopliteale. Aşa complicaţii ca parestezii sau echimoze au fost observate doar în 5 cazuri. Merită de subliniat absenţa sindromului dolor semnificativ în grupul pacienţilor studiaţi. Toţi bolnavii au fost externaţi peste 2 ore după intervenţie. Concluzii: Metoda are următoarele avantaje: durata scurtă a incapacităţii de muncă, utilizarea anesteziei locale, rezultatul estetic bun, durata redusă a intervenţiei, rezultatele precoce şi la distanţă favorabile, posibilitatea de obliterare a venelor cu diametrul mare şi lipsa necesităţii în analgezie postoperatorie.Introduction: Varicose veins of the lower limbs are a common condition affecting 10-15% of men and 20-25% of women in the developed countries of western world. This high prevalence is responsible for high medical and social costs. The aim was to study the clinical results of surgical treatment of patients with varicose veins of lower limbs using radiofrequency ablation (RFA). Material and methods: One hundred forty two patients with varicose veins underwent RFA of the above knee great saphenous vein by “VNUS Closure”™ procedure. The vein diameters were from 5 to 20 mm. The RF catheter was inserted via percutaneous puncture or through a small skin incision. All operations were performed under local, tumescent anesthesia, with ultrasound guidance. We studied morphological changes of the wall of great saphenous vein in patients who underwent treatment with RFA. Results: The depth of necrosis was within endothelial and subendothelial layer, but detachment of endothelial and subendothelial layers was characteristic with collapse and narrowing of vessel lumen. The special feature was lack of neoangiogenesis at the level of saphenofemoral and safenopopliteal junction. Such complications as paresthesia or ecchymosis were observed only in 5 cases. It should be noted that the studied patients had no significant pain syndrome. All patients were discharged 2 h after operation. Conclusions: Advantages of the method are shorter sick leave, using of local tumescent anesthesia, good cosmetic result, shorter duration of surgery, good immediate and late results, possibility to close the veins with a large diameter and no use of postoperative analgesics

Effect of temperature on the pores growth in the polycrystalline films of fusible metals

Ссылка на статью на русском языке: Дукаров С.В., Петрушенко С.И., Сухов В.Н., Чурилов И.Г. / Влияние температуры на рост пор в поликристаллических плёнках легкоплавких металлов // Вопросы атомной науки и техники. – 2014. – № 1(89) . – С.110–114The paper presents the results of study through porosity in polycrystalline films of lead, tin and indium deposited on amorphous carbon substrate. It is established that the heating of film exponentially increases of the average size of through pores and do not leads to an increase of their concentration, which is practically independent of the temperature until to the melting point. We have determined the activation energy of the surface self in the films of these metals. Приведены результаты исследования сквозной пористости в поликристаллических плёнках свинца, олова и индия, напыленных на аморфные углеродные подложки. Установлено, что нагрев плёнок вызывает экспоненциальное увеличение среднего размера сквозных пор и не приводит к увеличению их концентрации, которая практически не зависит от температуры вплоть до температуры плавления. Определена энергия активации поверхностной самодиффузии в плёнках этих металлов

The third mission of the university in the context of war and post-war recovery

In the conditions of the war of russia against Ukraine, which began on February 24, 2022, Ukrainian universities are playing roles that were not characteristic of them in peacetime. To the greatest extent, this concerns the university’s third mission, serving society and responding to its urgent needs. The purpose of this study is to identify and characterize new meaningful directions for implementing the third mission of the university in the conditions of war and post-war reconstruction. The study uses quantitative and qualitative bibliometric analysis combining various methods, in particular, quantitative and dynamic analysis of publications and citations, keyword analysis, cluster analysis and content analysis of publications. The study’s results proved the lack of conceptual studies devoted to the role of universities in the war and post-war reconstruction. The main clusters of implementing the third mission of universities and the existing and potential areas of activity of Ukraine’s universities during the war and post-war reconstruction that belong to them were determined. In conclusion, it is substantiated that a new dimension of the mission of universities is being formed, which is at the stage of its formation and needs time for the necessary transformations. Depending on the consequences of the war in Ukraine, it can be a separate cluster of the third mission of universities, and the selection of a new fourth mission of universities, dedicated to peacebuilding and the role of the university during the war and post-war recovery