2. Articole
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Item ВЫСОКОЧАСТОТНОЕ ЭЛЕКТРОИСКРОВОЕ ЛЕГИРОВАНИЕ – КАК СПОСОБ ПОВЫШЕНИЯ ФИЗИКО-ХИМИЧЕСКИХ СВОЙСТВ МЕТАЛЛИЧЕСКИХ ПОВЕРХНОСТЕЙ(CEP USM, 2024) Парамонов, Анатолий; Паршутин, Владимир; Коваль, АлександрItem МЕХАНИЧЕСКИЕ СВОЙСТВА КРИСТАЛЛОВ НА ОСНОВЕ ХАЛЬКОГЕНИДОВ СВИНЦА(CEP USM, 2024) Грабко, Дарья; Никорич, Валентина; Топал, Дарья; Шикимака, Ольга; Губанова, AнтонинаThe mechanical properties of binary chalcogenide compounds (pure and doped) and their solid solutions with a narrow band gap PbTe, Pb0.8sn0.2Te, Pb0.8Cd0.2Te, Pb0.8Mn0.2Te, Pb0.8Ge0.2Te and Pbse were investigated. using the method of indentation, the hardness and plasticity of the studied crystals was assessed as a function of the applied load in the range (P = 50 – 500) mn. The influence of Ga, Cd, In and B dopants on the deformation and nanomicrohardness of pure PbTe and Pbse crystals was investigated. It has been shown that all lead chalcogenides, both alloyed and ternary compounds, are highly plastic. It has been established that doped lead compounds and ternary semiconductors have higher hardness than the original binary compounds. In general, the microhardness of lead chalcogenides decreases monotonically with load increasing, but this change is no more than 10%. In some crystals, the transition from microindentation to nanoindentation is accompanied by the manifestation of the Indentation size effect (Ise). a “direct” Ise was observed on Pbse, PbTe:B and PbTe:Ga crystals, and a “reverse” Ise was observed on Pbse:In and Pbse:Ga crystals.Item НУКЛЕАЦИЯ НАНОЧАСТИЦ В ЭЛЕКТРОХИМИИ(CEP USM, 2024) Баранов, С.А.It is shown that the earlier discovered features of the composition and properties of electrochemical coatings obtained by the induced codeposition from alloys of iron-group metals (W, Mo, Re)—such as nanocrystallinity (X-ray amorphism), macroscopic dimensional effects of microhardness and corrosion resistance, the effect of the volume current density on the properties and composition—are a consequence of the fractality of the solutions of complexes (citrate, gluconate, etc.) in combination with the intensive interfacial exchange. In this case, the kinetics of nano-nucleation limits the size of the resulting alloy nucleus, as a result of which water molecules participate in the formation of coatings, leading to the incorporation of oxidehydroxide inclusions into the solid phase and hydrogenation.Item SINTEZA ȘI CARACTERIZAREA STRUCTURALĂ A COMPLEXULUI HETEROMETALIC {Co2 La2 } IZOBUTIRAT ÎN BAZA N-BUTILDIETANOLAMINEI(CEP USM, 2024) Stati, Dumitru; Kravțov, Victor; Baca, SvetlanaA new heterometalic [Co2 La2 (OH)2 (ib)4 (bdea)2 (NO3 )2 ]∙2MeCN (1) cluster has been syn thesized by the reaction of Co(II) isobutyrate (Hib = isobutyric acid) and La(NO3 )3 ∙ 6H2 O with N-butyldiethanolamine (H2 bdea) in acetonitrile. Single-crystal X-ray structural analysis reveals that 1 crystallizes with two acetonitrile molecules in the P21 /n space group of the monoclinic system with a = 14.769(5), b = 9.416(3), c = 19.538(6) Å, β=100.315(3)° and V = 2673.11(15) Å3 . Cluster 1 has a rhombic planar tetranuclear central core {Co(III)2 La(III)2 } best described as a „butterfly” motif with the La(III) ions ocupied the „body” positions and the Co(III) ions at the „wing” sites.Item POLIMER COORDINATIV UNI-DIMENSIONAL DE Cu(II) ÎN BAZA ACIDULUI IZOBUTIRIC ȘI PIRAZINĂ: SINTEZA ȘI STRUCTURA(CEP USM, 2024) Capbătut, Olga; Kravțov, Victor; Baca, SvetlanaCoordination polymers are playing an increasingly important role in the feld of inorganic chemistry. Of particular interest is the use of Cu(II) carboxylates to assemble new compounds involving various bridging ligands for the formation of coordination polymers. a new [Cu(is)2(pyz)] n coordination compound has been synthesized by the reaction of Co(II) isobutyrate with pyrazine (pyz) ligand in acetonitrile. a single-crystal X-ray diffraction analysis shows that the pepared compound is a one-dimensional coordination polymer in which the [Cu(is)2] units are connected by pyrazine ligands into chains.Item SINTEZA ȘI PROPRIETĂȚILE FIZICE A COMPLEXILOR POLIMERICI NOI LUMINESCENȚI Eux (Cht)1-x(CEP USM, 2024) Verlan, Victor; Culeac, Ion; Bordian, Olga; Robu, ȘtefanComlexii Eux (Cht)1-x pe bază de chitosan (Cht) și europiu trivalent au fost sintezați prin reacție termică directă dintre Eu((NO)3 )3 6H2 O și Cht în soluții de apă distilată și caracterizați prin spectroscopiile IR și fotoluminescență (FL). Vizualizarea microscopică a suprafeței materi alului și straturilor subțiri a dezvăluit o omogenitate bună, fără nici o separare de fază. Spectrele de emisie prezentă benzile înguste caracteristice ale ionului Eu3+ și banda largă cu maximumul la 480 nm atribuită lui Cht ca gazdă polimerică și ligand a Eu3+. În concluzie, complecșii Eux (Cht)1-x pot fi utilizați ca un nou material luminescent pentru aplicarea în medicină, biologie, optoelec tronică.Item SINTEZA ȘI CARACTERIZAREA CARBOXILAȚILOR HEPTANUCLEARI AI FIERULUI(III) PE BAZĂ DE DERIVAȚI AI DIETANOLAMINEI(CEP USM, 2024) Podgornîi, Daniel; Kravtsov, Victor; Baca, SvetlanaThis study focuses on the synthesis and characterization of heptanuclear iron(III) compo unds featuring polyalcoholamine ligands. Ultrasonic treatment of small trinuclear or hexanucle ar pivalate clusters and diethanolamine derivatives (R-deaH2 , R = CH3 (1); CH3 C6 H4 (2)) resul ted in two heptanuclear iron(III) clusters with general formula [Fe7 O2 (piv)9 (R-dea)3 (H2 O)3 ]. A single-crystal X-ray diffraction analysis shows that clusters 1 and 2 have a disk-like {Fe7 O3 } core in which the central FeIII atom linked to FeIII 6 hexagon by three µ3 -O2− groups. Six pivalates and three polyalcoholamine ligands additionally bridge all FeIII atoms. The remaining pivalates and three water molecules completed the coordination sphere of metal atoms. In summary, this study showcases the synthesis and characterization of heptanuclear iron(III) compounds with amine alcohol ligands, offering a deeper understanding of their structural properties, with promising implications for the field of coordination chemistry and advanced materials science.Item ЕСТЕСТВЕННЫЙ ФЕРРОМАГНИТНЫЙ РЕЗОНАНС В МИКРОПРОВОДЕ И ЕГО ПРИМЕНЕНИЯ(CEP USM, 2024) Баранов, С.А.The natural ferromagnetic resonance (nFMR) in cast glass-coated amorphous magnetic micro and nanowires has been studied theoretically and experimentally. The nFMR reveals large residual stresses appearing in the microwire core in the course of casting. These stresses, together with the magnetostriction, determine the magnetoelastic anisotropy. Beside the residual internal stresses, the nFMR frequency is influenced by external stresses applied to the microwire or to the composite containing the latter (the so-called stress effect). The dependence of the nFMR frequency on the deformation and external stresses for the microwires is proposed to be used in the distant diagnostics of dangerous deformations in medicine.Item ANALIZA SUPRAFEȚEI HIRSHFELD ALE INTERACȚIUNILOR INTERMOLECULARE ÎN CO-CRISTALE DE [Co(NH3)6]3+ ȘI ACID 3-SULFOBENZOIC(CEP USM, 2024) Beleaev, Ecaterina; Kravțov, Victor; Baca, SvetlanaHydrogen bonding has been shown to be predominant among the interaction types for systems involving the [Co(nH3)6]3+cation and various anions/molecules. This study examines the role of intermolecular bonds and their quantitative and qualitative investigation between 3-sulfobenzoic acid (3-sbH2) and the cobalt(III) hexaamine complex cation in molecular crystals. Two new multi-component compounds [Co(nH3)6]Cl(3-sb)·H2O (1) and [Co(nH3)6]2Cl2(3-sb) (sO4)·7H2O (2) were synthesized and characterized. The single crystal X-ray diffraction study reveals that in these compounds the complex cation [Co(nH3)6]3+ serves as a basic element for the incorporation of various anions/molecules and promotes the formation of multi-component compounds with extended networks via H-bonds. The analysis of the Hirshfeld surfaces allowed the quantitative and qualitative identifcation of the main contacts involved in the molecular packing of the crystals.Item ХАРАКТЕРИСТИКИ ПУЛЬСАЦИОННОЙ ТЕПЛОВОЙ ТРУБЫ ПРИ ВОЗДЕЙСТВИИ ЭЛЕКТРИЧЕСКОГО ПОЛЯ(CEP USM, 2024) Моторин, Олег; Болога, МирчаInfluence of electric field on thermal resistance of the closed-loop pulsating heat pipe (PHP) has been investigated experimentally. PHP is made from a long capillary copper tube with inner diameter of 1,9 mm and outer diameter of 3,0 mm bent into a planar serpentine with five U-turns filled with n-hexane. High voltage electrodes are located in the evaporation zone. Measurements of temperatures have been performed for range of 5-50 W applied heating power and for range of 5-18 kV DC voltage. At the heat input of 20 W and a voltage of 18 kV, a reduction in the thermal resistance of the PHP by 35% was obtained. A generalization of the obtained experimental data has been carried out. The temperature of the evaporation zone could be controlled within certain limits using the electric field, which can be used for thermostatting.Item ВЛИЯНИЕ КОНЦЕНТРАЦИИ КОМПОНЕНТОВ ГЛЮКОНАТНОГО ЭЛЕКТРОЛИТА НА ЭЛЕКТРООСАЖДЕНИЕ СПЛАВОВ КОБАЛЬТ-ВОЛЬФРАМ(CEP USM, 2024) Бобанова, Жанна; Петренко, Владимир; Ющенко, Сергей; Кроитору, ДумитруThe electrodeposition and properties of Co-W alloys prepared from concentrated gluconate electrolytes were studied. It was shown that high-quality alloy coatings with a high current efciency were formed when precursors changed from 0.1M to 0.5M at a ratio of the concentration of the citrate ligand and the fusion-forming components Co2+/WO42- (5:1). The leveling ability was determined from the results of proflograph measurements on the samples with a repeating sinusoidal profle. Gluconate electrolytes have better equalizing ability. smoothing of the profle of the deposited Co-W coatings was observed at sufciently large deposit thicknesses.Item CRYSTAL STRUCTURE AND HIRSHFELD SURFACE ANALYSIS OF 2,4-DIAMINO-6-PHENYL-1,3,5-TRIAZIN-1-IUM PERCHLORATE(CEP USM, 2024) Craciun, Nicoleta; Melnic, Elena; Fonari, Marina; Chişca, DianaSynthesis and characterization of new organic salt, 2,4-diamino-6-phenyl-1,3,5-triazin- 1-ium perchlorate (LH)(ClO4), in which NH ···O(N) hydrogen bonds play an essential role in stabilizing the crystal structure, were highlighted in the present study. The crystal structure was determined using single-crystal X-ray diffraction analysis, which reveals that the title compound crystallizes in the monoclinic centrosymmetric space group P21/c and contains one cation and one anion in the asymmetric unit. The unit cell parameters are a =13.8011(13) Å, b = 5.0674(5) Å, c = 16.6411(13) Å, and β = 91.930(9)˚. Also, the composition C9H10ClN5O4, of the discussed compound was confirmed by FTIR spectroscopy. From this research a decisive influence of hydrogen bonds on stability of the reported crystal is evidenced. The distribution of all types of intermolecular interactions was assessed by the Hirschfeld surface analysis method.Item DIAGNOSE OF BIOMOLECULES USING RAMAN INTERACTIONS OF THE LIGHT(CEP USM, 2024) Ţurcan, MarinaIt is particularly important by now to apply the light in processing and development of modern diagnostic. Here with, two basic aspects of the interaction of light with the substance are discussed: the nonlinear one of light interaction with the environment, and the cooperative aspect of interaction of photons with matter (atoms or biomolecules). One should mention the use of metamaterials for tissue decontamination where the specific form of contact surface plays an important role. Another goal of the present work is the study and use of the cooperative effects of bacteria and viruses located in the evanescent field of biomaterials during Raman interaction of light in ultraviolet region. A model is proposed based upon existing experiments which takes into account the local symmetry of biomolecules. New models emerging from the non-linear interaction of the atomic (molecular) subsystem and the electromagnetic field of cavity could be elaborated. The photons statistic is proposed for the diagnosis of the new collective processes.Item SEDIMENTAREA PROTEINELOR SERICE ÎN PUNCTUL IZOELECTRIC LA ELECTROACTIVAREA ZERULUI(CEP USM, 2024) Paladii, Irina; Vrabie, Elvira; Bologa, Mircea; Vrabie, Valeria; Stepurina, Tatiana; Policarpov, Albert; Sprincean, CătălinaThe electroactivation of whey generates the recovery of whey proteins into mineral protein concentrates, accompanied by a series of inter- and intramolecular changes through the activation of all the substances in the solid content, especially the protein content, which occur through the action of a series of protein aggregation mechanisms, in according to the classic chemical and biochemical properties of serum proteins. The variation of active acidity and redox potential in the cathode cell is not homogeneous, it expands during processing and ensures the sedimentation of serum proteins from whey at their isoelectric point, it demonstrates the influence of solid and protein content on the electroactivation of different types of whey and indicates the transition of aquacomplexes in hydrocomplexes, being more evident when processing whey with a low protein content.Item OPTIMIZATION OF AN EHD PUMP CHARACTERISTICS(CEP USM, 2024) Motorin, Oleg; Bologa, Mircea; Podlesny, IgorElectrohydrodynamic pumps generate flow in dielectric liquids. Two injection type electrohydodynamic pumps with blade-blade with insulation coating type electrodes and grid-grid type electrodes made of bare wires and wires covered with perforated insulation have been studied. There was a movable flow-limiting partition in the interelectrode space of the second pump. The current-voltage and pressure-flow rate characteristics of the pumps are given when using pure transformer oil, transformer oil-butanol mixtures ans polyethylsiloxane liquid. The optimal interelectrode gap distance, conductivity of the medium and position of the flow-limiting partition has been established, which ensures maximum pressure (in transformer oil, the pressure was 1.8 times higher than in polyethylsiloxane liquid).Item EXAMENUL DE BAC LA FIZIC{ – BARIERA DINTRE EVALUAȚI ȘI EVALUATORI(CEP USM, 2024) Cârlig, Sergiu; Bîzgan, Serghei; Rusu, AngelaThe participation of students in the BAC examination in PHYSICS is analyzed for the last three years, after the modification of the national curriculum and the syllabus for the examination. The authors’ experience as trainers is summarized and ways to increase the objectivity of the assessment of the Physics exam are discussed. Statistics are presented and conclusions are drawn.Item OSCILATORUL ANARMONIC(CEP USM, 2024) Cârlig, Sergiu; Bardeţchi, Profirie; Ciornea, Viorel; Macovei, MihaiThe article analyzes the influence of the non-linear terms of the restoring force at large deviations from the equilibrium position of an oscillating body (non-linear oscillator). Particularly, it is demonstrated, in an accessible way,that the oscillations of the anharmonic oscillator drastically differ from thoseof a harmonic one. The main reason lies in the fact the oscillator frequency ofthe nonlinear oscillator, at large deviations, begins to depend on the amplitudeof the oscillations.Item СХОДСТВО И РАЗЛИЧИЕ СПЕЦИФИКИ ДЕФОРМИРОВАНИЯ СТАЛИ AISI 316L В УСЛОВИЯХ ТРЕНИЯ И УДАРНОЙ НАГРУЗКИ(CEP USM, 2024) Грабко, Дарья; Пырцак, Константин; Присакару, Андриан; Топал, Дарья; Вилотич, Марко; Вилотич, Драгиша; Шикимака, ОльгаThe paper studies the formation of a hardened nano-microstructured (NMS) surface layer on AISI 316L stainless steel using two methods: light friction and light impact loading. The studies have shown that the forming NMS layer has both common and different features that can affect the properties of the modified material in different ways. The common features of the NMS layer under friction and impact loading include the fragmentation of the grain structure, the appearance of slip bands inside the grains, an increase in the strength and plasticity parameters. On the other hand, some differences are noted: a different degree of hardening in the NMS layer compared to the original undeformed surface, different sizes of the NMS layer, etc. Based on the obtained results, it can be assumed that the friction method can be used to obtain a slightly strengthened NMS layer with a thickness of about 500 μm. The impact load method is preferable for obtaining a more strengthened NMS layer of thickness ≈15-20 μm.Item СИНТЕЗ МНОГОКОМПОНЕНТНЫХ И МНОГОФУНКЦИОНАЛЬНЫХ ПОКРЫТИЙ В ПЛАЗМЕ НИЗКОВОЛЬТНОГО ИМПУЛЬСНОГО РАЗРЯДА(CEP USM, 2024) Михайлов, Валентин; Казак, Наталья; Ивашку, Сергей; Янакевич, Анатолий; Яцко, СпиридонThe synthesis of multicomponent and multifunctional coatings in low-voltage discharge plasma using compact electrodes made of graphite, refractory metals such as titanium, tantalum and tungsten, as well as their powders has been studied. Optimised energy regimes (energy value of electric discharges) have been identified at which the most qualitative coatings (uniform and continuous) with the highest content of carbide phases were obtained, which provide high hardness and service life under wear conditions. The utilisation of powders as alloying materials in lieu of compact electrodes has enabled the attainment of significantly thicker coatings and an enhancement in the process's productivity. This will facilitate the expansion of the technology's potential applications.Item QUANTUM HYBRID SYSTEM’S DYNAMICS via ENVIRONMENTAL THERMOSTAT(2024) Ceban, Victor; Cecoi, Elena; Cârlig, Sergiu; Macovei, Mihai