Browsing by Author "Sprincean, Veaceslav"

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DE ASUPRA TRECUTULUI. EXEMPLE DE ARHEOLOGIE AERIANĂ LA SITURILE EPOCII FIERULUI DIN REGIUNEA NISTRULUI DE MIJLOC
(CEP USM, 2023-05-26) Zanoci, Aurel; Sprincean, Veaceslav; Băț, Mihail
Caracterizarea structurală a nanoformațiunilor de Ga2O3 obținute prin tratament termic al monocristalelor Ga2O3 [Articol]
(Universitatea Tehnică din Moldova, 2018-05-24) Untilă, Dumitru; Sprincean, Veaceslav; Caraman, Mihail; Cojocaru, Ala; Lupan, Oleg; Tighineanu, Ion; Palachi, Leonid; Caraman, Iuliana
Prin tratament termic (TT), în atmosferă normală, al monocristalelor β-Ga2S3, cu rețea cristalină monoclinică, la temperaturi din intervalul 970-1170 K, timp de 3-6 ore, suprafața acestora se acoperă cu un strat omogen de β-Ga2O3, cu rețea cristalină monoclinică. La interfața monocristal-oxid se formează nanocristalite de Ga2O3 și Ga2S3. Structura cristalină și dimensiunile medii ale cristalitelor sunt analizate prin măsurări XRD, SEM și Raman.
Cercetarea spectrelor de reflectanța a microobiectelor biologice la distanța [Articol]
(CEP USM, 2020) Chiriţa, Arcadii; Caraman, Mihail; Sprincean, Veaceslav; Paladi, Florentin
COLECTAREA MICROPARTICULELOR SOLIDE DIN ATMOSFERA PENTRU CERCETAREA PROCESELOR DE POLUARE A AERULUI
(CEP USM, 2024) Chirița, Arcadi; Sprincean, Veaceslav; Paladi, Florentin
A new method for collecting solid particles polluting the atmosphere has been developed. The advantages of the proposed method make it possible to collect particulate matter from automobile exhaust polluting the atmosphere in real time using drones. Examination of collected particles can be done using various techniques without changing the shape, composition, or location of the particles. These studies show the possibility of microparticles collecting from the atmosphere and studying them using optical microscopy, atomic force microscopy, and microfluorescence.
Composition and surface optical properties of GaSe: Eu crystals before and after heat treatment [Articol]
(2024) Sprincean, Veaceslav; Haoyi, Qiu; Tjardts, Tim; Lupan, Oleg; Untila, Dumitru; Aktas, Oral Cenk; Adelung, Rainer; Leontie, Liviu; Cârlescu, Aurelian; Gurlui, Silviu; Caraman, Mihail
This work studies the technological preparation conditions, morphology, structural char- acteristics and elemental composition, and optical and photoluminescent properties of GaSe single crystals and Eu-doped β–Ga2O3 nanoformations on ε–GaSe:Eu single crystal substrate, obtained by heat treatment at 750–900 ◦C, with a duration from 30 min to 12 h, in water vapor-enriched atmosphere, of GaSe plates doped with 0.02–3.00 at. % Eu. The defects on the (0001) surface of GaSe:Eu plates serve as nucleation centers of β–Ga2O3:Eu crystallites. For 0.02 at. % Eu doping, the fundamental absorption edge of GaSe:Eu crystals at room temperature is formed by n = 1 direct excitons, while at 3.00 at. % doping, Eu completely shields the electron–hole bonds. The band gap of nanostructured β–Ga2O3:Eu layer, determined from diffuse reflectance spectra, depends on the dopant concentration and ranges from 4.64 eV to 4.87 eV, for 3.00 and 0.05 at. % doping, respectively. At 0.02 at. % doping level, the PL spectrum of ε–GaSe:Eu single crystals consists of the n = 1 exciton band, together with the impurity band with a maximum intensity at 800 nm. Fabry–Perrot cavities with a width of 9.3 μm are formed in these single crystals, which determine the interference structure of the impurity PL band. At 1.00–3.00 at. % Eu concentrations, the PL spectra of GaSe:Eu single crystals and β–Ga2O3:Eu nanowire/nanolamellae layers are determined by electronic transitions of Eu2+ and Eu3+ ions.
Consolidarea triunghiului cunoașterii „Educație-Cercetare-Inovare” la USM: studiu de caz [Articol]
(CEP USM, 2020) Bulimaga, Tatiana; Sprincean, Veaceslav; Paladi, Adian; Savva, Marianna; Paladi, Florentin
Articolul de față reprezintă o analiză a componentelor triunghiului cunoașterii „Educație -Cercetare-Inovare”, efectuată în baza studiului conținutului proiectului Erasmus+ CBHE Educație pentru Drone–eDrone, în atenție fiind luată legătura lor reciprocă și complementaritatea acestui proiect cu proiectul de cercetare Tehnologii fizice avansate cu aplicarea UVS în monitorizarea şi modelarea factorilor de mediu–Monitor3D, desfășurate la Universitatea de Stat din Moldova (USM). Sunt prezentate instrumentele și căile de transfer de cunoștințe de la un proiect educațional privind dezvoltarea capacităților instituției și de formare a competențelor la un proiect național de cercetare și inovare. Acest studiu de caz poate servi drept model și ar putea fi multiplicat și în cazul altor proiecte.
Crystallinity and optical properties of β-Ga2O3/Ga2S3 layered structure obtained by thermal annealing of Ga2S3 semiconductor [Articol]
(2021) Sprincean, Veaceslav; Lupan, Oleg; Caraman, Iuliana; Untila, Dumitru; Postica, Vasile; Cojocaru, Ala; Gapeeva, Anna; Palachi, Leonid; Adeling, Rainer; Tiginyanu, Ion; Caraman, Mihail
In this work, the β-Ga2O3 nanostructures were obtained by thermal annealing in air of β-Ga2S3 single crystals at relatively high temperatures of 970 K, 1070 K and 1170 K for 6 h. The structural, morphological, chemical and optical properties of β-Ga2O3–β-Ga2S3 layered composites grown at different temperatures were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) as well as photoluminescence spectroscopy (PL) and Raman spectroscopy. The results show that the properties of obtained β-Ga2O3–β-Ga2S3 composites were strongly influenced by the thermal annealing tem- perature. The XRD and Raman analyses confirmed the high crystalline quality of the formed β-Ga2O3 nano- structures. The absorption edge of the oxide is due to direct optical transitions. The optical bandwidth was estimated to be approximately 4.34-4.41 eV, depending on the annealing temperature. Annealing of the β-Ga2S3 monocrystals at a higher temperature of 1170 K showed the complete conversion of the surface to β-Ga2O3. These results demonstrate the possibility to grow high quality β-Ga2O3–β-Ga2S3 layered composites and β-Ga2O3 nanostructures in large quantities for various applications such as gas sensing, non-toxic biomedical imaging, nonlinear optical, as well as power device applications. Micro and nanocrystallites present on the surface of the Ga2O3 layer contribute to a diffusion of the incident light which leads to an increase of the absorption rate allowing thus to reduce the thickness of the Ga2O3 layer, in which the generation of unbalanced charge carriers takes place. By decreasing the Ga2O3 layer thickness in such layered composites, the efficiency of photovoltaic cells based on such junctions can be increased.
DATE PRELIMINARE PRIVIND UTILIZAREA SPECTROSCOPIEI EDS PENTRU STUDIUL MATERIALULUI TEGULAR DIN PRIMELE SECOLE P. CHR.*
(CEP USM, 2024) Matveev, Sergiu; Braniște, Tudor; Sprincean, Veaceslav
In the mid 20th century near Sobari village (Soroca District, Republic of Moldova) was discovered an archaeological site dated with the 3rd-4th centuries AD identified as a Sântana de Mureş-Černjachov archeological culture site. Its uniqueness compared to other similar sites from the space between Prut and Dniester Rivers is determined by the presence of a stone structure enforced with mortar inside which was found a building with walls built of stone and brick, roof of tiles, glass window and peristyle made of wood pillars set on stone bases. Archaeological research statistic data reveals thousands of pieces of tile material. Besides this complex, within the limits of the site, were also identified several structures made of wood smeared with clay, one of which inside the stone precinct. The presence of such a complex in the barbarian environment at a distance of around 300 km from the Roman Empire border raised discussion regarding its origin. Several hypothesizes were advanced: according to one the site had been created by people with origins in the provincial Roman environment, according to other this site was an attempt to strengthen the seat of the local leader, other researchers included the site in the category of Roman commercial-craftsman factories etc. The researchers’ opinion regarding the origin of the tile material are divided as well, most of whom consider them to be brought from the Empire, while other think they are of local production.
DETECTAREA SEMNALELOR DE FLUORESCENȚĂ A PLANTELOR LA DISTANŢĂ CU FOLOSIREA UAV
(CEP USM, 2022-11-10) Chiriţa, Arcadii; Sprincean, Veaceslav; Savva, Marianna; Paladi, Florentin
Detectarea semnalelor de fluorescență a plantelor la distanţă cu folosirea UaV [Articol]
(CEP USM, 2022-11-10) Chiriţa, Arcadii; Sprincean, Veaceslav; Savva, Marianna; Paladi, Florentin
Educaţie pentru Drone : Suport de curs
(CEP USM, 2019) Nedeoglo, Natalia; Rotaru, Corneliu; Sprincean, Veaceslav; Danici, Anton; Seinic, Valeriu; Vozian, Constantin; Cazan, Valeriu; Corcimari, Ion; Cebotaru, Eugenia
FOTOLUMINESCENȚA – METODĂ EXPERIMENTALĂ DE CARACTERIZARE A FACTORILOR DE MEDIU
(CEP USM, 2024) Sprincean, Veaceslav; Chirița, Arcadi; Caraman, Mihail
The excitation and photoluminescent emission mechanisms of the substrates in atomic, molecular, and solid state are analyzed. Experimental methods for the research of nanostructured material and composites based on GaS/GaSe layered semiconductors and β-Ga2O3 oxides doped with Eu and biological objects, leaves of fruit trees, and elements of clean fish (Leuciscus Squalius) are proposed. The influence of UVB radiation on the FL spectral structure of the studied materials was determined.
Fotorezistor pentru regiunea ultravioletă pe bază de strat din Nanofire de β-Ga2O3 [Articol]
(CEP USM, 2022-11-10) Vatavu, Elmira; Sprincean, Veaceslav; Dmitroglo, Liliana; Gurău, Virginia; Caraman, Mihail
Luminescence of β-Ga2O3 Nanoforms Obtained by Oxidation of GaSe Doped with Eu [Articol]
(Springer, Cham, 2020) Sprincean, Veaceslav; Untila, D.; Chirița, Arcadii; Evtodiev, I.; Caraman, I.
The GaSe single crystals were doped with Eu in the process of their synthesis and growth. The oxide of β-Ga2O3 doped with Eu in the form of massive nanowires was obtained by thermal treatment (TT) in the atmosphere of GaSe single crystals doped with 1.0 and 3.0 at.% of Eu. The crystalline structure, surface morphology and photoluminescence spectra of GaSe:Eu and β-Ga2O3:Eu single crystals were studied. The Photoluminescence (FL) spectrum of GaSe doped with 1.0 at.% of Eu at room temperature is formed as a result of transitions of 5D0 →7F1 to Eu3+ ion and as a result of radiation annihilation of n = 1 excitons in GaSe. The FL spectra of Ga2O3:Eu was interpreted on the basis of the energy level diagram of electrons in Eu3+ ion.
Micro and nanocomposites of gallium oxides and chalcogens as radiation receivers and gas sensors [Articol]
(Editura USM, 2024) Sprincean, Veaceslav; Caraman, Mihail
By thermal treatment (TT) in water vapor atmosphere at 750 ℃ and 900 ℃ of β-GaS and εGaSe single-crystalline wafers, Ga2S3/Ga2Se3 - GaS/GaSe and β-Ga2O3 - GaSe/GaSe layers formed by nanowires and nanopangles photosensitive in the far Ultra-Violet (UVC) region were obtained. The electrical conductivity of β-Ga2O3 layer on GaS/GaSe substrate increases under the influence of water vapor. The link between the relative humidity of water vapor in the atmosphere and the electrical conductivity of the β-Ga2O3 layer was established.
Monitorizarea proceselor de dezvoltare a plantelor prin măsurări ale spectrelor optice [Articol]
(CEP USM, 2020) Sprincean, Veaceslav; Caraman, Mihail; Chiriţa, Arcadii; Paladi, Florentin
OPORTUNITĂȚI DE UTILIZARE ÎN PRACTICĂ A TEHNOLOGIILOR INTELIGENTE ÎN EVALUAREA UNOR VARIABILE BIOLOGICE
(CEP USM, 2023) Bîrsan, Ana; Sprincean, Veaceslav; Ganea, Ion
Tehnologiile avansate bazate pe UVA au fost utilizate pentru monitorizarea unor ecositeme naturale și artificiale din aria protejată Rezervația Natural-Cuturală Orheiul Vechi. Analiza unor variabile biologice cu rol hotărâtor în asigurarea sustenabilității ecosistemelor s-a efectuat cu ajutorul camerelor multispectrale. Metodele utilizate au oferit posibilitatea identificării elementelor principale ale zonei studiate și au permis clasificarea acestora în patru clase principale de utilizare/acoperire a terenurilor: 1) teren acoperit cu vegetație spontană (ierburi, arbuşti și arbori), 2) teren agricol cultivat; 3) teren lipsit de vegetaţie; 4) teren cu construcții. Senzorii multispectrali s-au arătat a fi eficienți în identificarea diferitor componente ale mediului, demonstrând oportunități de utilizare a acestora în menținerea și îmbunătățirea calității serviciilor ecosistemice și utilizarea durabilă a resurselor naturale.
Optical and photosensitive properties of flexible n (p)–InSe/In2O3 heterojunctions [Articol]
(2022) Sprincean, Veaceslav; Leontie, Liviu; Caraman, Iuliana; Untila, Dumitru; Girtan, Mihaela; Gurlui, Silviu; Lisnic, Petru; Doroftei, Corneliu; Cârlescu, Aurelian; Iaconi, Felicia; Caraman, Mihail
In this work, optical, including photoluminescence and photosensitivity, characteristics of micrometer-sized flexible n (p)–InSe/In2O3 heterojunctions, obtained by heat treatment of single- crystalline InSe plates doped with (0.5 at.%) Cd (Sn), in a water-vapor- and oxygen-enriched at- mosphere, are investigated. The Raman spectrum of In2O3 layers on an InSe:Sn substrate, in the wavelength range of 105–700 cm−1, contains the vibration band characteristic of the cubic (bcc-In2O3) phase. As revealed by EDX spectra, the In2O3 layer, ~2 μm thick, formed on InSe:Cd contains an ~18% excess of atomic oxygen. The absorption edge of InSe:Sn (Cd)/In2O3 structures was stud- ied by ultraviolet reflectance spectroscopy and found to be 3.57 eV and ~3.67 eV for InSe:Cd and InSe:Sn substrates, respectively. By photoluminescence analysis, the influence of doping impuri- ties on the emission bands of In2O3:Sn (Cd) was revealed and the energies of dopant-induced and oxygen-induced levels created by diffusion into the InSe layer from the InSe/In2O3 interface were determined. The n (p)–InSe/In2O3 structures display a significantly wide spectral range of photosen- sitivity (1.2–4.0 eV), from ultraviolet to near infrared. The influence of Cd and Sn concentrations on the photosensitivity and recombination of nonequilibrium charge carriers in n (p)–InSe layers from the heterojunction interface was also studied. The as-obtained nanosized InSe/In2O3 structures are suitable for optoelectronic applications.
Parcul digital 3D al monumentelor de arhitectură din Chișinău: inovație și valorificarea patrimoniului cultural [Articol]
(Editura USM, 2024) Sprincean, Veaceslav; Pascari, Serghe; Savva, Marianna; Matveev, Sergiu
UAV-based photogrammetry technologies allow the architectural and aesthetic details of monuments to be captured with extreme precision, which helps to thoroughly document their current condition. These models can be used for further restoration, even if the monument would suffer degradation or destruction. The 3D models act as a digital archive of monuments, making it possible to preserve cultural elements in virtual format even if they physically disappear.
Porous InP as piezoelectric component in magneto-electric composite sensors [Articol]
(io, 2011) Gerngross, M.-D.; Sprincean, Veaceslav; Leisner, M.; Carstensen, J.; Föll, H.; Tiginyanu, Ion
We report on the fabrication of cheap piezoelectric porous InP templates by electrochemical etching and additional purely chemical post-etching and on the galvanic filling of the resulting nanopore array with Ni-Fe using a highly viscous electrolyte. The d14 component of porous InP is found to be around a stunning |60| pm/V. The deposited Ni-Fe shows a very narrow hysteresis loop with low coercive field strength (170 G) and very low remanence (0.005 emu).