2. Articole
Permanent URI for this collectionhttps://msuir.usm.md/handle/123456789/47
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Item Certificarea produselor ecologice(CEP USM, 2024) Caraman, ValeriaThe paper explores the certification process for organic products, examining its importance, challenges and impact on the environment and consumer behaviour. It highlights the growing demand for sustainable practices and products, driven by increasing public awareness of environmental and health issues. The study includes a detailed analysis of the current regulatory framework, comparative case studies and the role of certification bodies, identifying areas for improvement to improve the certification process and support sustainable development.Item Integrarea obiectelor (programe, formulare) în SAP conform legislaţiei RM(CEP USM, 2024) Spînu, DanThe research “Integration of objects (programs, forms) in SAP according to Moldovan legislation” is focused on analysing and proposing effective solutions for integrating necessary objects into SAP systems to comply with Moldovan legislation. The research highlights the importance of efficient SAP integration to meet fiscal and legal requirements, ensuring operational efficiency and legal conformity. It provides theoretical insights and practical applications for Moldovan companies using SAP, facilitating adherence to local fiscal and reporting standards.Item Modalităţi de creare şi implementare a activităţilor digitale interactive la informatică(CEP USM, 2024) Chitorog, AnaThe research „Methods of creating and implementing interactive digital activities in teaching Computer Science”analyzed the didactic systems for studying informatics, and the evolution of ICT integration in the educational process, and highlighted the following central idea: the implementation of ICT has a substantial impact and advanced performance, not only from a cognitive perspective or evaluation, but also in the space of cultivating feelings and motivation for teaching and for the permanent study of new information technologies. It ensures the realization of the principle of continuity in learning, adapted through the prism of ICT implementation in the didactic process.Item CARACTERIZAREA STRUCTURALĂ A STRATURILOR SUBȚIRI DE Sb2Te3 FABRICATE PRIN METODA SUBLIMĂRII ÎN VOLUM CUAZI-ÎNCHIS(CEP USM, 2024) Untila, Dumitru; Lungu, Ion; Suman, Victor; Gadiac, Ivan; Potlog, TamaraStraturi subțiri de Sb2Te3 au fost obținute pe suporturi de sticlă ITO/CdS prin metoda sublimării în volum cuazi-închis (CSS). Prin analiza difracției razelor X, s-a constatat că straturile subțiri de Sb2Te3 au rețea cristalină hexagonală, ce aparține grupului spațial P6/mmm. Creșterea temperaturii evaporatorului de la 470°C până la 530°C, duce la modificarea orientării preferabile de creștere a cristalitelor compusului Sb2Te3 și la creșterea gradului de cristalinitate a acestuia. Investigațiile Raman, au confirmat rezultatele XRD și au fost folosite pentru a obține informații suplimentare asupra structurii straturilor subțiri de Sb2Te3. Caracteristica dubletului observat la 119,54 cm–1 și 138,83 cm–1, precum și la 93,65 cm-1 si 107,36 cm-1 cu intensitate integrală foarte mică pot fi atribuite interacțiunii Te-Te între pachetele de telurură de antimoniu.Item DEZVOLTAREA TIMPURIE A DINAMICII FLUIDELOR: PARTEA I(CEP USM, 2024) Cernica, Ion M.The evolution of fluid dynamics from ancient times to the end of the 18th century is presented. It is shown that fluid dynamics appeared with the creation of the first means of production and evolved together with the economic development of society and human civilization. The hydrotechnical achievements associated with those in the fields of navigation and pneumatics gave fluid dynamics, at the initial stage of development, a predominant applicative character and this orientation was preserved for many centuries in a row. In the sense we assign today, fluid dynamics was initiated in the 17th century, when the resistance to the advance of solid bodies in fluid media had become an important problem for the science and technology of that time. Knowledge of water and air resistance was needed in the design of ships, cannons, water mills and windmills. The scientific achievements that marked the early development of fluid dynamics are described, and the role of prominent researchers in this field is shown.Item ORIENTATION-DEPENDENT OXYGEN EVOLUTION ACTIVITY OF EPITAXIAL RUDDLESDEN−POPPER PR 0.5Ca1.5MnO4 THIN FILMS(2024) Ottinger, Natalie; Belenciuc, Alexandr; Șapoval, Oleg; Hausmann, Christopher; Moșneaga, Vasilii; Jooss, Christian; Qian, Ma; Fatemeh, EbrahimiStudying the oxygen evolution reaction (OER) on anisotropic perovskite oxides with different surface orientations improves our understanding of how surface structure, chemistry, catalytic stability, and activity are related. Here, we present a comparative electrochemical study of(001)- and (010)-oriented epitaxial thin films of Ruddlesden−Popper (n = 1) Pr0.5Ca1.5MnO4(RP-PCMO) grown on Nb:SrTiO3 (STNO) substrates of different orientations with using buffer layers. The results on epitaxial films are compared with those of the RP-PCMO powder. The OER activity and stability are studied using cyclic voltammetry and rotating ring disk electrodes under alkaline conditions. In addition, an analysis of their surface structure and chemistry by AFM and XPS before and after electrochemical measurements was carried out. The RP-PCMO powder shows high stability during electrochemical cycling. In contrast, the two differently oriented thin films are both corroding, while the (010)-oriented films reveal a higher activity and stability than the (001)-oriented ones. The variation in electrochemical activity and stability of the polycrystalline and single-crystalline RP-PCMO electrodes of different orientations is related to their different surface chemistry. In particular, it depends on the different Mn/Pr/Ca ratios and their different rates of Ca leaching, which is governed by the orientation-dependent Ca hydroxide surface concentration.Item PLASTIC DEFORMATION AND MICROHARDNESS OF Pb 1-xYbxTe SINGLE CRYSTALS UNDER QUASI-STATIC AND SCLEROMETRIC INDENTATION(2021) Grabco, Daria; Nicorici, Valentina; Topal, Daria; Pârțac, Constantin; Șichimaca, OlgaIn this work, the microhardness and specificity of deformation of Pb 1-xYbxTe single crystals by quasi-static and sclerometric indentation are studied. It is shown that these crystals are distinguished by high plasticity and low microhardness both under indentation and under the movement of the indenter. An opinion is expressed that the mechanism of crystal structure compaction is involved in mass transfer during the formation of an imprint, along with the dislocation mechanism. Crystals have low sclerometric anisotropy of hardness along different crystallographic directions on the (001) plane, which is typical for crystals of a cubic system. The jump-like mechanism of the deformation process during the movement of the indenter, which is characteristic of crystals of different types, is confirmed.Item LUMINESCENT PROPERTIES OF LOW-DIMENSIONAL ZnO:Ag POWDERS OBTAINED BY CHEMICAL DEPOSITION FROM AQUEOUS SOLUTION(2023) Goglidze, Tatiana; Goncearenco, Evghenii; Dementiev, Igor; Nedeoglo, Natalia; Iurieva, Tatiana; Nedeoglo, DumitruPhotoluminescence (PL) spectra of ZnO:Ag highly dispersed powders obtained by chemical deposition from aqueous solution are investigated in the wavelength range between 360 and 750 nm at room temperature under excitation between 250 and 350 nm. Before starting the synthesis, the Ag dopant was introduced into the initial solution in the form of AgNO3 silver nitrate in the amount of 12, 102, and 252 mg. The PL spectra consist of an ultraviolet emission (380 nm) attributed to AgZn acceptor-bound exciton, a short-wavelength violet emission (400 –450 nm) and a wide long-wavelength yellow-orange emission (560 – 600 nm). With decreasing excitation energy, the violet emission decreases in intensity, while the yellow-orange emission increases. This is caused by the phenomenon of self-absorption of the short-wavelength emission and energy transmission to the centers of the long-wavelength emission. A rapid decrease in intensity of all the PL bands is found for the sample with maximum Ag concentration. This fact is due to the appearance of the second phase in the form of silver oxide and, consequently, a decrease in the concentration of AgZn point defects responsible for the bands.Item AERO-Ga2O3 NANOMATERIAL ELECTROMAGNETICALLY TRANSPARENT FROM MICROWAVES TO TERAHERTZ FOR INTERNET OF THINGS APPLICATIONS(2020) Braniște, Tudor; Dragoman, Mircea; Jucov, Serghei; Aldrigo, Martino; Ciobanu, Vladimir; Iordănescu, Sergiu; Alîabîeva, Liudmila; Fumagalli, Francesco; Ceccone, Giacomo; Raevschi, Simion; Schűtt, Fabian; Adelung, Rainer; Colpo, Pascal; Gorșunov, Boris; Tighineanu, IonIn this paper, fabrication of a new material is reported, the so-called Aero-Ga2O3 or Aerogallox, which represents an ultra-porous and ultra-lightweight three-dimensional architecture made from interconnected microtubes of gallium oxide with nanometer thin walls. The material is fabricated using epitaxial growth of an ultrathin layer of gallium nitride on zinc oxide microtetrapods fabricated using epitaxial growth of an ultrathin layer of gallium nitride on zinc oxide microtetrapods followed by decomposition of sacrificial ZnO and oxidation of GaN which according to the results of X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS) characterizations, is transformed gradually in β-Ga2O3 with almost stoichiometric composition. The investigations show that the developed ultra-porous Aerogallox exhibits extremely low reflectivity and high transmissivity in an ultrabroadband electromagnetic spectrum ranging from X-band (8–12 GHz) to several terahertz which opens possibilities for quite new applications of gallium oxide, previously not anticipated.Item AERO-TiO2 PREPARED ON THE BASIS OF NETWORKS OF ZnO TETRAPODS(2022) Ciobanu, Vladimir; Ursachi, Veaceslav; Lehmann, Sebastian; Braniște, Tudor; Raevschi, Simion; Zamalai, Victor V.; Monaico, Eduard V.; Colpo, Pascal; Nielsch, Kornelius; Tighineanu, IonIn this paper, new aeromaterials are proposed on the basis of titania thin films deposited using atomic layer deposition (ALD) on a sacrificial network of ZnO microtetrapods. The technol-ogy consists of two technological steps applied after ALD, namely, thermal treatment at different temperatures and etching of the sacrificial template. Two procedures are applied for etching, one of which is wet etching in a citric acid aqua solution, while the other one is etching in a hydride vapor phase epitaxy (HVPE) system with HCl and hydrogen chemicals. The morphology, composition, and crystal structure of the produced aeromaterials are investigated depending on the temperature of annealing and the sequence of the technological steps. The performed photoluminescence analysis suggests that the developed aeromaterials are potential candidates for photocatalytic applications.