Romanian Reports in Physics最新文献_第4页

Seismic noise analysis in the microseismic and high-frequency domain at the BURAR seismic stations BURAR地震台站微震和高频域地震噪声分析

4区物理与天体物理

Romanian Reports in Physics Pub Date : 2023-09-15 DOI: 10.59277/romrepphys.2023.75.705

A. TOLEA, C. GRECU, I.A. MOLDOVAN, V.E. TOADER

{"title":"Seismic noise analysis in the microseismic and high-frequency domain at the BURAR seismic stations","authors":"A. TOLEA, C. GRECU, I.A. MOLDOVAN, V.E. TOADER","doi":"10.59277/romrepphys.2023.75.705","DOIUrl":"https://doi.org/10.59277/romrepphys.2023.75.705","url":null,"abstract":"\"In the absence of earthquakes, seismic stations continuously record the Earth's vibrations, called ambient seismic noise (ASN). The main concern regarding the ASN records is improving the seismic data quality using different tools developed especially for this purpose. Power Spectral Densities (PSD) and their corresponding Probability Density Functions (PDF) are tools used to evaluate the station performance and reveal the noise level at the station’s site. For high frequencies (>1 Hz), the noise sources are from cultural activities and show diurnal variation, while for low frequencies (<1 Hz), the noise is generated by natural sources and shows seasonal variation. In this study, we analyzed the vertical components of the Bucovina array seismic network (BURAR) to characterize the noise levels at the stations and investigate noise variations in space and time. We computed four-year spectrograms for some elements of the array that revealed an increase of ASN in the 2–5 Hz frequency range during the warmer seasons, contrary to the colder months. On the other hand, at lower frequencies (0.5–1 Hz), the power of seismic noise increases during the year’s colder months. We examined the relationship between noise levels and weather parameters (e.g., wind speed) for the station where the seismic sensor is collocated, with a weather station. We observed that an increase in wind speed leads to an increase in the noise level at high frequencies (> 2 Hz).\"","PeriodicalId":49588,"journal":{"name":"Romanian Reports in Physics","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135486606","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

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

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

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

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":"62 1","pages":"444-454"},"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