European Physical Journal-applied Physics最新文献

{"title":"Sustained coherent epitaxy and role of oxygen vacancies in La0.7Sr0.3MnO3−δ thin films grown on SrTiO3 by sputtering","authors":"M. Lmouchter, M. Suzuki","doi":"10.1051/EPJAP/2021200365","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200365","url":null,"abstract":"Ferromagnetic La0.7 Sr0.3 MnO3−δ (LSMO) epitaxial thin films of single-crystal quality with very smooth surfaces are grown on SrTiO3 (100) substrates by on-axis rf magnetron sputtering. We find that the resistivity and the spontaneous magnetization for these 180 nm thick films are nearly equal to those of single crystals after thermal annealing. On the other hand, the Curie temperature T C is no higher than 270 K, a value far below the bulk one, which is quite unusual. As a clue to this riddle, we note a strong correlation between the lattice constant for these films and the amount of oxygen vacancies in the case of LSMO, an oxygen-nonstoichiometric oxide. From this, we conclude that the sustained coherent epitaxy takes place to match the lattice mismatch of 0.8% by incorporating a limited amount of oxygen vacancies, which relaxes the film in-plane stress while functions to significantly reduce T C .","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"78 1","pages":"60301"},"PeriodicalIF":1.0,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81628556","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}

{"title":"Structural and optical properties of molybdenum oxide thin films prepared by the dip coating technique","authors":"D. Ahmad, M. A. Khan, A. Mahmood, A. Sohail, S. Gillani","doi":"10.1051/EPJAP/2021200366","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200366","url":null,"abstract":"Due to their excellent structural and optical properties of molybdenum oxide thin films are used in various applications such as gas-sensing, solar cells, optoelectronic and medical physics. The present study is related to the synthesis of molybdenum oxide thin films prepared by dip coating technique and the films were characterized by using various techniques such as XRD, SEM and UV-visible spectroscopy. The monoclinic crystal structure and the crystallite size (29.16–52.77 nm) was investigated by X rays diffraction (XRD) analysis. SEM micrograph was used to identify the nano tubes in MoO3 thin film and UV-visible spectroscopy exhibits the maximum absorption in ultra-violet region and band gap decrease (3.17–2.71 eV) with increased the inner transition states in molybdenum thin film. Finally, the results show that the series of molybdenum oxides MoO1 (Sample 1), MoO2 (Sample 2) and MoO3 (sample 3) exhibited interesting structural and optical properties which make them good candidates for photo catalytic activity.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"57 1","pages":"30301"},"PeriodicalIF":1.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75951231","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}

{"title":"Fabrication and repair of GaN nanorods by plasma etching with self-assembled nickel nanomasks","authors":"Shiying Zhang, Lei Zhang, Yueyao Zhong, Guodong Wang, Qingjun Xu","doi":"10.1051/EPJAP/2021210002","DOIUrl":"https://doi.org/10.1051/EPJAP/2021210002","url":null,"abstract":"High crystal quality GaN nanorod arrays were fabricated by inductively coupled plasma (ICP) etching using self-organized nickel (Ni) nano-islands mask on GaN film and subsequent repaired process including annealing in ammonia and KOH etching. The Ni nano-islands have been formed by rapid thermal annealing, whose density, shape, and dimensions were regulated by annealing temperature and Ni layer thickness. The structural and optical properties of the nanorods obtained from GaN epitaxial layers were comparatively studied by high-resolution X-ray diffraction (HRXRD), Raman spectroscopy and photoluminescence (PL). The results indicate that damage induced by plasma can be successfully healed by annealing in NH3 at 900 °C. The average diameter of the as-etched nanorod was effectively reduced and the plasma etch damage was removed after a wet treatment process in a KOH solution. It was found that the diameter of the GaN nanorod was continuously reduced and the PL intensity first increased, then reduced and finally increased as the KOH etching time sequentially increased.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"209 1","pages":"30405"},"PeriodicalIF":1.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77284922","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}

{"title":"Effect of Ca and/or Mn substitution on thermoelectric properties of SrTiO3","authors":"D. M. Radheep","doi":"10.1051/EPJAP/2021200297","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200297","url":null,"abstract":"Thermoelectric properties have been investigated for Sr0.5 Ca0.5 Ti1-x Mnx O3 (x  = 0.25, 0.5, 0.75) and Sr0.75 Ca0.25 Ti0.75 Mn0.25 O3 perovskite polycrystalline samples synthesized by solid-state reaction method. Following physical properties such as thermal conductivity, electrical resistivity, Seebeck coefficient, power factor and figure of merit (ZT) were measured. The substitution of Ca2+ in Sr2+ site or/and mixed valence Mn in Ti site creates appreciable enhancement in the thermoelectric properties with an increase of ZT from 0.5 to 0.69 at room temperature. The origin for the enrichment of ZT of the investigated samples around room temperature is due to substitution induced distortion in the cubic lattice.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"718 1","pages":"30902"},"PeriodicalIF":1.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74765662","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}

{"title":"Fast response acetone-sensing properties of SnO2 nanoparticles prepared by the sol-gel method","authors":"Jiaxing Wang, Haijing Yu, Yong Zhang","doi":"10.1051/EPJAP/2021200361","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200361","url":null,"abstract":"SnO2 nanoparticle architectures were successfully synthesized using a sol-gel method and developed for acetone gas detection. The morphology and structure of the particles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The SnO2 nanoparticle architectures were configured as high-performance sensors to detect acetone and showed a very fast response time ( nanoparticles should be promising candidates for designing and fabricating acetone gas sensors with good gas sensing performance. The possible gas sensing mechanism is also presented.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"62 1","pages":"30401"},"PeriodicalIF":1.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72765603","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}

{"title":"An experimental and theoretical correlation of inhibition effect of some dihydropyridine on mild steel in 1 M HCL","authors":"I. Fahim, M. Tridane, S. Belaaouad","doi":"10.1051/epjap/2021200229","DOIUrl":"https://doi.org/10.1051/epjap/2021200229","url":null,"abstract":"The corrosion inhibition of mild steel in 1 M HCl solution by some dihydropyridine has been studied using gravimetric, electrochemical impedance spectroscopy, potentiodynamic polarization techniques and quantum chemical study. The results of weight loss and Tafel polarization measurements showed that among the studied compounds, Isradipine has good inhibiting properties for steel corrosion in acidic bath, with 98% inhibition efficiency at optimum concentration 400 ppm. The inhibition is of a mixed anodic–cathodic nature. The adsorption behaviour of the investigated compounds is found to obey Langmuir adsorption isotherm. Quantum chemical parameters were correlated with the experimental results.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"43 1","pages":"21301"},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90921888","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}

{"title":"Enhanced photoelectrochemical performance of TiO2 nanofiber arrays decorated with CdS nanoparticles via SILAR method","authors":"J. Naceur, R. Ouertani, F. Jrad, S. Khamlich, W. Dimassi, R. Chtourou","doi":"10.1051/EPJAP/2021200249","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200249","url":null,"abstract":"In this paper, we report the photoelectrochemical performances of CdS nanoparticles (NPs) decorated TiO2 photoanodes. The TiO2 nanofiber arrays (NFAs) were fabricated into Titanium substrate by a hydrothermal method. Afterwards, the deposited TiO2 NFAs were decorated with CdS NPs by employing a successive ionic layer adsorption and reaction (SILAR) method. The obtained samples of CdS covered and uncovered TiO2 NFAs were characterized by X-ray diffraction, Scanning Electron Microscopy and UV-visible Diffuse Reflectance Spectroscopy. The size of the CdS nanoparticles increases with the number of SILAR cycles and leads to an additional broad absorption peak in the visible part of the spectrum. Consequently, the photo-electrochemical performance of the CdS decorated TiO2 was enhanced substantially resulting in a better electron-hole separation and transport. This enhancement has been discussed and assigned to a better sun light harvesting and an efficient charge transfer between the CdS nanoparticles and the TiO2 NFAs.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"85 1","pages":"20302"},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83224900","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}

{"title":"Modeling and optimization of organic tandem photovoltaic solar cells using silver nanowires as electrode and interconnecting layer","authors":"Imen Houiji, M. Mahdouani, Mahfoudh Raïssi, R. Bourguiga","doi":"10.1051/EPJAP/2021200354","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200354","url":null,"abstract":"Much research has been conducted to improve the performance of photovoltaic solar cells. Transparent conductive film and interconnection layers have a significant impact on the performance of photovoltaic cells. In this work, we analyze the experimental results obtained on tandem organic photovoltaic solar cells with simple inverted structures using silver nanowires AgNW as transparent conductive electrode (TE) and as interconnection layer (ICL) between PEDOT: PSS and ZnO. This type of contact leads to a strong ohmic contact in both sub-cells having P3HT: ICBA as the lower active layer and having PTB7: PC71BM (1: 1.5) as the upper active layer with a good complement of the absorption spectrum. To study the advantages of using AgNWs as an interconnection layer (PEDOT: PSS/AgNWs/ZnO) in tandem photovoltaic solar cells and as an anode and its impact on the performance of these organic cells, we have simulated the electrical characteristics obtained by these tandem organic photovoltaic cells using an equivalent circuit model. This model is based on a single diode model with five photovoltaic parameters. We therefore extracted all the physical parameters of the illuminated photovoltaic cell from its experimental characteristics (J–V), such as the diode saturation current density (J0 ), the series and shunt resistors (RS , RSh ), the ideality factor (n) and the photogenerated current density (JPh ). For this we have solved the analytical equations of the current density using Newton Raphson's method. The equations are derived from the single diode equivalent circuit proposed to simulate the measured current density as a function of the voltage of the manufactured tandem type organic solar cells. A good agreement was obtained between the theoretical model and the experimental electrical characteristics. This confirms that the use of AgNWs between PEDOT: PSS and ZnO as an interconnection layer in reverse geometry of these tandem devices, has improved the efficiency (PCE = 9.24%) and is proving to be an efficient recombination layer for tandem organic photovoltaic solar cells.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"18 1","pages":"20202"},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78799412","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}

{"title":"A neural network approach for improved bearing prognostics of wind turbine generators","authors":"Sharaf Eddine Kramti, Jaouher Ben Ali, L. Saidi, M. Sayadi, M. Bouchouicha, Eric Bechhoefer","doi":"10.1051/EPJAP/2021200259","DOIUrl":"https://doi.org/10.1051/EPJAP/2021200259","url":null,"abstract":"Condition monitoring of High-Speed Shaft Bearing (HSSB) in Wind Turbine Generators (WTGs) remains a challenging subject for industrial and academic studies. The investigation of mechanical vibration signals presents the most popular method in the literature. Consequently, this work involves a novel data-driven approach for direct HSSB prognosis using the vibration analysis. The proposed method is based on the computation of traditional statistical metrics derived both from the time-domain and frequency-domain via Spectral Kurtosis (SK). Then, the selection of the most suitable features was made using three metrics (monotonicity, trendability, prognosablity) to guarantee a better generalization of the trained Elman Neural Network (ENN). The validation of the proposed method was done using the benchmark of the center for Intelligent Maintenance Systems (IMS) for training and real measured Green Power Monitoring Systems (GPMS) data for testing. We have provided two links for downloading these data sets. The experimental results show that the proposed approach presents a powerful prediction tool. Comparative results with previous work show several advantages for the proposed combination of statistical metrics and ENN, such as the external prediction and real online estimation of the Remaining Useful Life (RUL). Also, some new practical findings are provided in the discussion.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"21 1","pages":"20901"},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75008958","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}

{"title":"Effect of cavity parameters on the propagation of shock wave generated by underwater pulsed discharge","authors":"Jin Yang, Zhenghao He, Zhuoyu Zhang, Yuchen Liu, Ming Yin","doi":"10.1051/epjap/2021200325","DOIUrl":"https://doi.org/10.1051/epjap/2021200325","url":null,"abstract":"In order to optimize the shock wave generated by underwater pulsed discharge, the relationship between cavity parameters and shock wave propagation is further studied by three-dimensional numerical simulation. According to the sound pressure field distribution obtained by the simulation, the reflection of the shock wave by the reactor wall can be clearly observed. The reflected pressure wave will reach its maximum value and then gradually attenuate. The study also found that when the deposition energy is constant, when the initial radius of the arc channel increases from 0.1 mm to 2.5 mm, the maximum amplitude of the shock wave will increase from 0.22 × 105 Pa to 1.70 × 105 Pa. When the initial radius of the arc channel is constant, as the deposition energy increases, the time to radiate the shock wave becomes earlier, and the maximum amplitude of the shock wave will increase. This means that a higher pressure can be generated by increasing the input of the deposition energy. When the deposition energy is constant, a higher-pressure level can be obtained by increasing the initial radius of the channel. The excitation frequency also affects the shock wave amplitude. Higher excitation frequency can obtain higher pressure amplitude. These methods will increase the efficiency of underwater pulse discharge treatment of bacteria.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"1 1","pages":"20801"},"PeriodicalIF":1.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86921522","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}