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Magnetically active composites with relatively giant dielectric permittivity 具有较大介电常数的磁活性复合材料
4区 物理与天体物理
Romanian Reports in Physics Pub Date : 2023-09-15 DOI: 10.59277/romrepphys.2023.75.503
M. BUNOIU, G.-E. IACOBESCU, G. PASCU, L. CHIRIGIU, I. BICA
{"title":"Magnetically active composites with relatively giant dielectric permittivity","authors":"M. BUNOIU, G.-E. IACOBESCU, G. PASCU, L. CHIRIGIU, I. BICA","doi":"10.59277/romrepphys.2023.75.503","DOIUrl":"https://doi.org/10.59277/romrepphys.2023.75.503","url":null,"abstract":"\"Magnetically active composites based on silicone rubber, silicone oil, carbonyl microparticles, graphene nanopallets and fabric, as a reinforcing element, are manufactured. For a constant amount of carbonyl iron microparticles and silicone oil, and for different ratios between the amounts of silicone rubber and graphene nanopalets, three composite samples are prepared. Using the plane capacitor method, the relative permittivity of the composites is determined. It is shown that by using graphene nanopallets, composites with giant values of relative dielectric permittivity can be obtained and that the relative dielectric permittivity values are sensitive to the magnetic force induced by the static magnetic field superimposed on the medium-frequency electric field. Using the model of the dipolar magnetic approximation and elements of the theory of dielectrics in medium frequency electric fields, the mechanisms participating in the obtained effects are described.\"","PeriodicalId":49588,"journal":{"name":"Romanian Reports in Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135486607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Innovative strategy based on green nanotechnology for elimination and reduction of aquatic weeds 基于绿色纳米技术消除和减少水草的创新策略
4区 物理与天体物理
Romanian Reports in Physics Pub Date : 2023-09-15 DOI: 10.59277/romrepphys.2023.75.604
M.-E. BARBINTA-PATRASCU, C. NICHITA, S. ANTOHE
{"title":"Innovative strategy based on green nanotechnology for elimination and reduction of aquatic weeds","authors":"M.-E. BARBINTA-PATRASCU, C. NICHITA, S. ANTOHE","doi":"10.59277/romrepphys.2023.75.604","DOIUrl":"https://doi.org/10.59277/romrepphys.2023.75.604","url":null,"abstract":"\"This study reports an interesting idea to convert aqueous extracts of invasive terrestrial plants [Johnsongrass (Sorghum halepense L.) and Knotgrass (Polygonum aviculare L.)] into valuable silver nanoparticles (AgNPs), and used them against aquatic weeds (Cladophora). The phyto-generated AgNPs presented nano scaled dimension (estimated by DLS), and good antioxidant activities (evaluated by chemiluminescence technique). UV-Vis absorption spectroscopy confirmed the AgNPs phyto-development. The total polyphenols (TPC) and total flavonoid (TFC) contents of the aqueous herbal extracts and of AgNPs phyto-generated from them, revealed the major contribution of polyphenols and flavonoids to phyto-reduction of silver ions, and also, they are responsible for the antioxidant properties of the obtained samples. The bio impact of the prepared AgNPs against Cladophora depends on the AgNPs dose, and the time exposure. These findings could be useful in for various biomedical, agronomic, and biotechnological applications.\"","PeriodicalId":49588,"journal":{"name":"Romanian Reports in Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135486608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Optical cryptographic communications with non-identical chaotic laser systems 非相同混沌激光系统的光密码通信
4区 物理与天体物理
Romanian Reports in Physics Pub Date : 2023-09-15 DOI: 10.59277/romrepphys.2023.75.408
I.R. ANDREI, S. SIMION, F. GAROI, M. BULINSKI, M.L. PASCU
{"title":"Optical cryptographic communications with non-identical chaotic laser systems","authors":"I.R. ANDREI, S. SIMION, F. GAROI, M. BULINSKI, M.L. PASCU","doi":"10.59277/romrepphys.2023.75.408","DOIUrl":"https://doi.org/10.59277/romrepphys.2023.75.408","url":null,"abstract":"\"We report secure data transmission performed using chaotic lasers with different external cavity geometries and applying the chaotic masking method based on subcarrier and phase modulations of the chaotic optical carrier. Two semiconductor lasers with similar multimode emission spectra and self-optical feedback provided, respectively, by ring and linear external cavities, were optically coupled and chaotically synchronized into a master – slave scheme. The transmitted message frequency modulates the radio frequency signal which modulates in phase the master chaotic carrier. Based on the robustness of the used encryption method and the synchronization characteristics of the two lasers, the decryption is conducted by the simple radio frequency spectrum monitoring of the slave emission.\"","PeriodicalId":49588,"journal":{"name":"Romanian Reports in Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135486442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The study of capillarity phenomena by means of ImageJ software 利用ImageJ软件研究毛细管现象
4区 物理与天体物理
Romanian Reports in Physics Pub Date : 2023-09-15 DOI: 10.59277/romrepphys.2023.75.909
ADRIANA RADU, DANIELA STOICA, M. V. POPESCU, C. BERLIC, CRISTINA MIRON, V. BARNA
{"title":"The study of capillarity phenomena by means of ImageJ software","authors":"ADRIANA RADU, DANIELA STOICA, M. V. POPESCU, C. BERLIC, CRISTINA MIRON, V. BARNA","doi":"10.59277/romrepphys.2023.75.909","DOIUrl":"https://doi.org/10.59277/romrepphys.2023.75.909","url":null,"abstract":"\"Capillarity phenomena appear due to different molecular forces acting between fluid molecules located at the interface with either another fluid or a solid. The macroscopic description of the phenomenon can be done in terms of surface tension. In this paper, we determined the surface tension coefficient of aqueous solution of potassium permanganate by means of Jurin's law and also made diameter measurements and capillary ascents on images by using ImageJ software. Furthermore, we studied the capillary phenomena between two parallel and non- parallel plates. In the case of non-parallel plates, employing a special plugin of the ImageJ software, we determined the equation of the rectangular hyperbola drawn by the surface of liquid rising between plates. These experiments can be performed at elementary level and, additionally, used as a stimulus to discover more advanced topics.\"","PeriodicalId":49588,"journal":{"name":"Romanian Reports in Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135486601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
DYNAMICAL COMPLEXITY ANALYSIS OF SACCADIC EYE MOVEMENTS IN TWO DIFFERENT PSYCHOLOGICAL CONDITIONS. 两种不同心理状态下跳眼运动的动态复杂性分析。
IF 2.7 4区 物理与天体物理
Romanian Reports in Physics Pub Date : 2014-01-01
C Aştefănoaei, D Creangă, E Pretegiani, L M Optican, A Rufa
{"title":"DYNAMICAL COMPLEXITY ANALYSIS OF SACCADIC EYE MOVEMENTS IN TWO DIFFERENT PSYCHOLOGICAL CONDITIONS.","authors":"C Aştefănoaei,&nbsp;D Creangă,&nbsp;E Pretegiani,&nbsp;L M Optican,&nbsp;A Rufa","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Saccadic eye movements of a normal subject were assessed through semi-quantitative analysis algorithms based on linear and non-linear test application in order to highlight the dynamics type characterizing saccadic neural system behavior. These movements were recorded during a simple visually-guided saccade test and one with a cognitive load involving button pressing to show a decision. Following the application of specific computational tests, chaotic dynamical trend dominancy was mostly revealed with some differences between the two saccade recording conditions: auto-correlation time was increased from 170 to 240 by cognitive task superposition and the Hurst exponent was enhanced from 0.52 to 0.76, denoting more persistence in the dynamics of saccadic system during increased neural activity related to cognitive task.</p>","PeriodicalId":49588,"journal":{"name":"Romanian Reports in Physics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4331081/pdf/nihms656971.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33069278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Efficient random laser effect in a new dye-nematic liquid crystalline composite 一种新型染料向列液晶复合材料的高效随机激光效应
IF 2.7 4区 物理与天体物理
Romanian Reports in Physics Pub Date : 1900-01-01 DOI: 10.5072/ZENODO.35094
V. Barna, V. Vlad, A. Petris, I. Dancus, T. Bazaru, E. Barna, A. Luca, S. Ferjani, G. Strangi
{"title":"Efficient random laser effect in a new dye-nematic liquid crystalline composite","authors":"V. Barna, V. Vlad, A. Petris, I. Dancus, T. Bazaru, E. Barna, A. Luca, S. Ferjani, G. Strangi","doi":"10.5072/ZENODO.35094","DOIUrl":"https://doi.org/10.5072/ZENODO.35094","url":null,"abstract":"Random lasing effects in fully disordered systems with organic and inorganic nature have been the subject of extensive studies since the beginning of the past decade. In multiple scattering materials the optical diffusion may induce a phase transition in the photon transport behavior. Beyond a critical scattering level, the system makes a transition into a strongly localized state and light transmission is therefore inhibited. This effect can be used as a photon trapping mechanism to obtain laser action in the presence of a gain medium. In this paper we present the first experimental evidence of random laser action in a dye doped nematic liquid crystal (ZLI-2659) with negative dielectric anisotropy. This material exhibits long-range dielectric tensor fluctuations, favoring the multiple scattering. When exceeding a certain threshold pump power value, the fluorescence curve in the system collapses and distinct sharp peaks emerge above the residual spontaneous emission spectrum. The laser emission has several interesting features - linewidth of the laser peaks is extremely narrow banded (approximately 0.5nm FWHM), very low threshold (30 µJ/mm 2 ), high efficiency (~ 20%). The unforeseen surviving of constructive interference in repeated multiple scattering events of the dye emitted photons provide the necessary optical feedback for lasing in our nematic liquid crystalline system. We analyze the main physical characteristics of these relatively novel phenomena, by also including here the case of various confinement geometries for the active medium. These scientific aspects overlook features of great interest characteristic of laser physics and material science.","PeriodicalId":49588,"journal":{"name":"Romanian Reports in Physics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70791345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
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