Pub Date : 2020-11-18DOI: 10.1051/epjap/2020200233
A. Talbi, M. Haouari, K. Nouneh, E. Feddi, M. Addou
Understanding the behavior of single dopant in semiconductors is a challenge to attain a high control on optoelectronic devices. Based on the fact that the external perturbations have an important impact on properties of doped nanocrystals, we have studied the simultaneous effects of phonons and conduction band non-parabolicity combined to dielectric mismatch and donor position on the photoionization cross section of an off-center donor in spherical GaN/InN core-shell quantum dots. The calculations were carried out within the framework of the effective-mass approximation and the eigenvalues equation has been solved using the Ritz variational method. The examination of the photoionization cross section, corresponding to the first donor energy level and the non-parabolic conduction band optical transition, shows clearly that the existence of non-parabolicity band or dielectric environment causes a blue shift of resonance peaks while the existence of phonon red shift them with a non-neglected variations in their intensity. The donor position has also an important effect on peaks position and amplitude.
{"title":"Impact of conduction band non-parabolicity and dielectric mismatch on photoionization cross section of donor bound polaron in spherical GaN/InN core-shell nanoparticle","authors":"A. Talbi, M. Haouari, K. Nouneh, E. Feddi, M. Addou","doi":"10.1051/epjap/2020200233","DOIUrl":"https://doi.org/10.1051/epjap/2020200233","url":null,"abstract":"Understanding the behavior of single dopant in semiconductors is a challenge to attain a high control on optoelectronic devices. Based on the fact that the external perturbations have an important impact on properties of doped nanocrystals, we have studied the simultaneous effects of phonons and conduction band non-parabolicity combined to dielectric mismatch and donor position on the photoionization cross section of an off-center donor in spherical GaN/InN core-shell quantum dots. The calculations were carried out within the framework of the effective-mass approximation and the eigenvalues equation has been solved using the Ritz variational method. The examination of the photoionization cross section, corresponding to the first donor energy level and the non-parabolic conduction band optical transition, shows clearly that the existence of non-parabolicity band or dielectric environment causes a blue shift of resonance peaks while the existence of phonon red shift them with a non-neglected variations in their intensity. The donor position has also an important effect on peaks position and amplitude.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"28 2 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78169675","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}
Pub Date : 2020-11-01DOI: 10.1051/epjap/2020200258
Bo Li, Xiaofeng Li, Zhu Zhifeng, Q. Gao
Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for quantitative diagnostics of gases. The spatial resolution of LIBS, however, is limited by the volume of plasma. Here femtosecond-nanosecond dual-pulsed LIBS was demonstrated. Using this method, the breakdown threshold was reduced by 80%, and decay of continuous radiation was shortened. In addition, the volume of the plasma was shrunk by 85% and hence, the spatial resolution of LIBS was significantly improved.
{"title":"Nanosecond laser-induced breakdown assisted by femtosecond laser pre-ionization in air: the effect on spatial resolution and continuous radiation","authors":"Bo Li, Xiaofeng Li, Zhu Zhifeng, Q. Gao","doi":"10.1051/epjap/2020200258","DOIUrl":"https://doi.org/10.1051/epjap/2020200258","url":null,"abstract":"Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for quantitative diagnostics of gases. The spatial resolution of LIBS, however, is limited by the volume of plasma. Here femtosecond-nanosecond dual-pulsed LIBS was demonstrated. Using this method, the breakdown threshold was reduced by 80%, and decay of continuous radiation was shortened. In addition, the volume of the plasma was shrunk by 85% and hence, the spatial resolution of LIBS was significantly improved.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"8 1","pages":"20701"},"PeriodicalIF":1.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82804109","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}
Pub Date : 2020-11-01DOI: 10.1051/epjap/2020200075
E. Dul’kin, M. Roth
In relaxor (1-x )SrTiO3 -x BiFeO3 ferroelectrics ceramics (x = 0.2, 0.3 and 0.4) both intermediate temperatures and Burns temperatures were successfully detected and their behavior were investigated in dependence on an external bias field using an acoustic emission. All these temperatures exhibit a non-trivial behavior, i.e. attain the minima at some threshold fields as a bias field enhances. It is established that the threshold fields decrease as x increases in (1-x )SrTiO3 -x BiFeO3 , as it previously observed in (1-x )SrTiO3 -x BaTiO3 (E. Dul'kin, J. Zhai, M. Roth, Phys. Status Solidi B 252 , 2079 (2015)). Based on the data of the threshold fields the mechanisms of arising of random electric fields are discussed and their strengths are compared in both these relaxor ferroelectrics.
在弛豫(1-x)SrTiO3 -x BiFeO3铁电陶瓷(x = 0.2, 0.3和0.4)中，成功地检测了中间温度和Burns温度，并利用声发射研究了它们依赖于外部偏置场的行为。所有这些温度都表现出非平凡的行为，即随着偏置场的增强，在某些阈值场达到最小值。在(1-x)SrTiO3 -x BiFeO3中，阈值场随着x的增加而减小，正如之前在(1-x)SrTiO3 -x BaTiO3中观察到的那样(E. Dul'kin, J. Zhai, M. Roth, Phys。固体状态B 252, 2079(2015))。根据阈值场的数据，讨论了随机电场的产生机理，并比较了两种弛豫铁电体中随机电场的强度。
{"title":"Comparison of random field strengths in (1-x)SrTiO3-xBiFeO3 and (1-x)SrTiO3-xBaTiO3 relaxor ferroelectrics by means of acoustic emission","authors":"E. Dul’kin, M. Roth","doi":"10.1051/epjap/2020200075","DOIUrl":"https://doi.org/10.1051/epjap/2020200075","url":null,"abstract":"In relaxor (1-x )SrTiO3 -x BiFeO3 ferroelectrics ceramics (x = 0.2, 0.3 and 0.4) both intermediate temperatures and Burns temperatures were successfully detected and their behavior were investigated in dependence on an external bias field using an acoustic emission. All these temperatures exhibit a non-trivial behavior, i.e. attain the minima at some threshold fields as a bias field enhances. It is established that the threshold fields decrease as x increases in (1-x )SrTiO3 -x BiFeO3 , as it previously observed in (1-x )SrTiO3 -x BaTiO3 (E. Dul'kin, J. Zhai, M. Roth, Phys. Status Solidi B 252 , 2079 (2015)). Based on the data of the threshold fields the mechanisms of arising of random electric fields are discussed and their strengths are compared in both these relaxor ferroelectrics.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"31 1","pages":"20401"},"PeriodicalIF":1.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75077332","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}
Pub Date : 2020-11-01DOI: 10.1051/epjap/2020200031
H. Bouchekhou, H. Allag, M. Mekidèche, J. Lévêque, L. Gueraiche
The originality of this work is to applied Amperian Approach for modelling HTS bulk especially in electrical motor applications. This approach has proven its efficiency in electrical materials having a constant conductivity. For HTS materials, the resistivity change brutally and have a non linear comportment through any external magnetic field variations. To success the modelisation, we have to create an iterative procedure. All simulation steps are based on the power law model for computing resistivity and current densities adding the fixed point method for non linear iterations. The majority of our results concern the current densities in the HTS bulk rotor with different critical currents constatations under mgnetic field created by three phase coils of the proposed superconducting synchronous motor (SSM) prototype. Some results are consolidated by numerical way using flux 2D software.
{"title":"New approach to study HTS bulk behavior for a fully superconducting motor design","authors":"H. Bouchekhou, H. Allag, M. Mekidèche, J. Lévêque, L. Gueraiche","doi":"10.1051/epjap/2020200031","DOIUrl":"https://doi.org/10.1051/epjap/2020200031","url":null,"abstract":"The originality of this work is to applied Amperian Approach for modelling HTS bulk especially in electrical motor applications. This approach has proven its efficiency in electrical materials having a constant conductivity. For HTS materials, the resistivity change brutally and have a non linear comportment through any external magnetic field variations. To success the modelisation, we have to create an iterative procedure. All simulation steps are based on the power law model for computing resistivity and current densities adding the fixed point method for non linear iterations. The majority of our results concern the current densities in the HTS bulk rotor with different critical currents constatations under mgnetic field created by three phase coils of the proposed superconducting synchronous motor (SSM) prototype. Some results are consolidated by numerical way using flux 2D software.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"15 1","pages":"20904"},"PeriodicalIF":1.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77845185","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}
Pub Date : 2020-11-01DOI: 10.1051/EPJAP/2020200127
Selma M. H. Al-Jawad, N. Imran, M. R. Mohammad
In this work, TiO2 nanostructure thin films were deposited by using anodization technique, while CdS thin films were deposited on TiO2 films by two methods chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR). The structure of TiO2 /CdS films were investigated and analyzed by XRD, SEM, and AFM, but the optical properties were investigated by UV–visible spectroscopy, PL spectroscopy, and spectral response. XRD analysis of all deposited films has confirmed the formation of two phases one is tetragonal phase (anatase, and rutile) for TiO2 , and second hexagonal phase which belong to CdS layer. SEM images of TiO2 nanotubes arrays (NTAs)/CdS showed the TiO2 NTs walls become decorated with aggregates of fine CdS nanoparticles that partly penetrate into the TiO2 NTAs pores. AFM measurements displayed increase in the surface roughness compared with TiO2 films. PL measurement results of TiO2 /CdS core–shell show two peaks, one is located at UV-region pointed to energy band gap for TiO2 nano films, and second one is located at visible region pointing to recombination of photogenerated electron–hole pairs within CdS layers. Spectral response measurements showed photocurrent peaks for all TiO2 /CdS films deposited with different electrolyte solution have red-shift to visible region. When illuminated with a UV–Vis light source, the TiO2 /CdS core–shell films displayed high response. A higher response to UV–Vis light was attained with the use of TiO2 NTAs/CdS films prepared by anodization /CBD. This approach offers a technique for fabricating photoelectrodes.
{"title":"Effect of electrolyte solution and deposition methods on TiO2/CdS core–shell nanotube arrays for photoelectrocatalytic application","authors":"Selma M. H. Al-Jawad, N. Imran, M. R. Mohammad","doi":"10.1051/EPJAP/2020200127","DOIUrl":"https://doi.org/10.1051/EPJAP/2020200127","url":null,"abstract":"In this work, TiO2 nanostructure thin films were deposited by using anodization technique, while CdS thin films were deposited on TiO2 films by two methods chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR). The structure of TiO2 /CdS films were investigated and analyzed by XRD, SEM, and AFM, but the optical properties were investigated by UV–visible spectroscopy, PL spectroscopy, and spectral response. XRD analysis of all deposited films has confirmed the formation of two phases one is tetragonal phase (anatase, and rutile) for TiO2 , and second hexagonal phase which belong to CdS layer. SEM images of TiO2 nanotubes arrays (NTAs)/CdS showed the TiO2 NTs walls become decorated with aggregates of fine CdS nanoparticles that partly penetrate into the TiO2 NTAs pores. AFM measurements displayed increase in the surface roughness compared with TiO2 films. PL measurement results of TiO2 /CdS core–shell show two peaks, one is located at UV-region pointed to energy band gap for TiO2 nano films, and second one is located at visible region pointing to recombination of photogenerated electron–hole pairs within CdS layers. Spectral response measurements showed photocurrent peaks for all TiO2 /CdS films deposited with different electrolyte solution have red-shift to visible region. When illuminated with a UV–Vis light source, the TiO2 /CdS core–shell films displayed high response. A higher response to UV–Vis light was attained with the use of TiO2 NTAs/CdS films prepared by anodization /CBD. This approach offers a technique for fabricating photoelectrodes.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"74 1","pages":"20102"},"PeriodicalIF":1.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77208580","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}
Pub Date : 2020-11-01DOI: 10.1051/epjap/2020200071
B. Mousavi, Morteza Rezaei Talarposhti, F. Karbassian, A. Mousavi
Metal-assisted chemical etching (MACE) is applied for fabrication of silicon nanowires (SiNWs). We have shown the effect of amorphous sheath of SiNWs by treating the nanowires with SF6 and the resulting reduction of absorption bandwidth, i.e. making SiNWs semi-transparent in near-infrared (IR). For the first time, by treating the fabricated SiNWs with copper containing HF∕H2O2∕H2O solution, we have generated crystalline nanowires with broader light absorption spectrum, up to λ = 1 μm. Both the absorption and photo-luminescence (PL) of the SiNWs are observed from visible to IR wavelengths. It is found that the SiNWs have PL at visible and near Infrared wavelengths, which may infer presence of mechanisms such as forbidden gap transitions other can involvement of plasmonic resonances. Non-radiative recombination of excitons is one of the reasons behind absorption of SiNWs. Also, on the dielectric metal interface, the absorption mechanism can be due to plasmonic dissipation or plasmon-assisted generation of excitons in the indirect band-gap material. Comparison between nanowires with and without metallic nanoparticles has revealed the effect of nanoparticles on absorption enhancement. The broader near IR absorption, paves the way for applications like hyperthermia of cancer while the optical transition in near IR also facilitates harvesting electromagnetic energy at a broad spectrum from visible to IR.
{"title":"Plasmon-assisted interaction of Si with light, for cancer hyperthermia and electromagnetic energy harvest","authors":"B. Mousavi, Morteza Rezaei Talarposhti, F. Karbassian, A. Mousavi","doi":"10.1051/epjap/2020200071","DOIUrl":"https://doi.org/10.1051/epjap/2020200071","url":null,"abstract":"Metal-assisted chemical etching (MACE) is applied for fabrication of silicon nanowires (SiNWs). We have shown the effect of amorphous sheath of SiNWs by treating the nanowires with SF6 and the resulting reduction of absorption bandwidth, i.e. making SiNWs semi-transparent in near-infrared (IR). For the first time, by treating the fabricated SiNWs with copper containing HF∕H2O2∕H2O solution, we have generated crystalline nanowires with broader light absorption spectrum, up to λ = 1 μm. Both the absorption and photo-luminescence (PL) of the SiNWs are observed from visible to IR wavelengths. It is found that the SiNWs have PL at visible and near Infrared wavelengths, which may infer presence of mechanisms such as forbidden gap transitions other can involvement of plasmonic resonances. Non-radiative recombination of excitons is one of the reasons behind absorption of SiNWs. Also, on the dielectric metal interface, the absorption mechanism can be due to plasmonic dissipation or plasmon-assisted generation of excitons in the indirect band-gap material. Comparison between nanowires with and without metallic nanoparticles has revealed the effect of nanoparticles on absorption enhancement. The broader near IR absorption, paves the way for applications like hyperthermia of cancer while the optical transition in near IR also facilitates harvesting electromagnetic energy at a broad spectrum from visible to IR.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"44 1","pages":"20101"},"PeriodicalIF":1.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74725955","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}
Pub Date : 2020-11-01DOI: 10.1051/EPJAP/2020200237
R. Ghosh, R. Chakraborty
A two dimensional square lattice photonic crystal (PhC) formed by placing glass matrix in air is proposed for subwavelength imaging around 840 nm. The superlensing behavior at relatively lower wavelength compared to other reported PhC superlens is obtained by this configuration. Other advantages of using glass is that they have lower optical absorption at this wavelength and is relatively cheap. By placing the proposed PhC arrangement between the object and the objective of a conventional optical microscope, superlensing effect can be realized. Moreover, any change in radius of glass rod during fabrication process can result in the shift of superlensing wavelength.
{"title":"Superlensing property of 2-D glass photonic crystal","authors":"R. Ghosh, R. Chakraborty","doi":"10.1051/EPJAP/2020200237","DOIUrl":"https://doi.org/10.1051/EPJAP/2020200237","url":null,"abstract":"A two dimensional square lattice photonic crystal (PhC) formed by placing glass matrix in air is proposed for subwavelength imaging around 840 nm. The superlensing behavior at relatively lower wavelength compared to other reported PhC superlens is obtained by this configuration. Other advantages of using glass is that they have lower optical absorption at this wavelength and is relatively cheap. By placing the proposed PhC arrangement between the object and the objective of a conventional optical microscope, superlensing effect can be realized. Moreover, any change in radius of glass rod during fabrication process can result in the shift of superlensing wavelength.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"1 1","pages":"20501"},"PeriodicalIF":1.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89489759","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}
Pub Date : 2020-11-01DOI: 10.1051/epjap/2020200176
S. Bhattacharyya, S. Das, H. Chattopadhyay
Heat transfer performance of microchannel are becoming an important area of research with the current fast growing scenario of high speed computing and miniaturized electronic devices. These devices pile up large amount of heat accompanied by smaller surface area to release it. The current work examines unsteady, laminar flow heat transfer inside a novel twisted sinusoidal wavy microchannel. The channel with square cross section is wavy in nature as well as twisted. The first half portion of the channel is twisted clockwise, whereas the twist in the remaining part is having counterclockwise twist. The novel geometry promotes mixing of fluid layers leading to transport augmentation. The inlet pulsation follows sinusoidal pattern in time. The thermal performance parameter of the proposed novel geometry was assessed within a Reynolds number range of 1–100. Both the pulsation amplitude and Strouhal number are varied during the course of this study. To solve the governing equations, a finite volume based method was utilized. The Nusselt number data shows significant enhancement for the sinusoidal inlet velocity as compared to that of the steady case, i.e. without inlet flow pulsation. The performance enhancement criterion combining heat transfer and pressure drop shows significant improvement over steady flow case as well as for one-way twisted tube. Entropy generation, which is the measure of dissipated energy, is also reported in the present work.
{"title":"Thermohydraulic characteristics and entropy analysis of a novel clockwise and anti-clockwise twisted sinusoidal wavy micro-channel under pulsating inlet condition","authors":"S. Bhattacharyya, S. Das, H. Chattopadhyay","doi":"10.1051/epjap/2020200176","DOIUrl":"https://doi.org/10.1051/epjap/2020200176","url":null,"abstract":"Heat transfer performance of microchannel are becoming an important area of research with the current fast growing scenario of high speed computing and miniaturized electronic devices. These devices pile up large amount of heat accompanied by smaller surface area to release it. The current work examines unsteady, laminar flow heat transfer inside a novel twisted sinusoidal wavy microchannel. The channel with square cross section is wavy in nature as well as twisted. The first half portion of the channel is twisted clockwise, whereas the twist in the remaining part is having counterclockwise twist. The novel geometry promotes mixing of fluid layers leading to transport augmentation. The inlet pulsation follows sinusoidal pattern in time. The thermal performance parameter of the proposed novel geometry was assessed within a Reynolds number range of 1–100. Both the pulsation amplitude and Strouhal number are varied during the course of this study. To solve the governing equations, a finite volume based method was utilized. The Nusselt number data shows significant enhancement for the sinusoidal inlet velocity as compared to that of the steady case, i.e. without inlet flow pulsation. The performance enhancement criterion combining heat transfer and pressure drop shows significant improvement over steady flow case as well as for one-way twisted tube. Entropy generation, which is the measure of dissipated energy, is also reported in the present work.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"122 1","pages":"20903"},"PeriodicalIF":1.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74656336","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}
Pub Date : 2020-11-01DOI: 10.1051/epjap/2020200034
A. Smara, T. Reis, V. Climente-Alarcón, B. Glowacki
Trapped field magnets of superconducting stacks could be an alternative to conventional magnets in electrical machine applications. A conceptual design of an electrical motor using these stacks was proposed in [,]. Superconducting stacks offer many advantages; however, they can be demagnetized when exposed to the varying field present in electrical motors during operation. This varying field can be generated by salient magnetic circuit or generated from the armature winding as harmonics. To study this demagnetization effect, we carried out an experiment on a superconducting stack in an electrical machine, exposing it to different levels of varying cross and normal fields. The experimental measurements recorded a demagnetization of the stack. In this work, the analyses of the reduction of magnetization of the superconducting stack by an alternating normal field and the comparison of the results with experimental measurements in the electrical motor are presented.
{"title":"Magnetization reduction by varying normal field in stacks of composite superconductors in an electrical motor","authors":"A. Smara, T. Reis, V. Climente-Alarcón, B. Glowacki","doi":"10.1051/epjap/2020200034","DOIUrl":"https://doi.org/10.1051/epjap/2020200034","url":null,"abstract":"Trapped field magnets of superconducting stacks could be an alternative to conventional magnets in electrical machine applications. A conceptual design of an electrical motor using these stacks was proposed in [,]. Superconducting stacks offer many advantages; however, they can be demagnetized when exposed to the varying field present in electrical motors during operation. This varying field can be generated by salient magnetic circuit or generated from the armature winding as harmonics. To study this demagnetization effect, we carried out an experiment on a superconducting stack in an electrical machine, exposing it to different levels of varying cross and normal fields. The experimental measurements recorded a demagnetization of the stack. In this work, the analyses of the reduction of magnetization of the superconducting stack by an alternating normal field and the comparison of the results with experimental measurements in the electrical motor are presented.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"10 1","pages":"20902"},"PeriodicalIF":1.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88731075","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}
Pub Date : 2020-11-01DOI: 10.1051/epjap/2020200213
A. Kuddus, Md. Ferdous Rahman, J. Hossain, A. Ismail
This article presents the role of Bi-layer anti-reflection coating (ARC) of TiO2 /ZnO and back surface field (BSF) of V2 O5 for improving the photovoltaic performance of Cadmium Sulfide (CdS) and Cadmium Telluride (CdTe) based heterojunction solar cells (HJSCs). The simulation was performed at different concentrations, thickness, defect densities of each active materials and working temperatures to optimize the most excellent structure and working conditions for achieving the highest cell performance using obtained optical and electrical parameters value from the experimental investigation on spin-coated CdS, CdTe, ZnO, TiO2 and V2 O5 thin films deposited on the glass substrate. The simulation results reveal that the designed CdS/CdTe based heterojunction cell offers the highest efficiency, η of ∼25% with an enhanced open-circuit voltage, V oc of 0.811 V, short circuit current density, J sc of 38.51 mA cm−2 , fill factor, FF of 80% with bi-layer ARC and BSF. Moreover, it appears that the TiO2 /ZnO bi-layer ARC, as well as ETL and V2 O5 as BSF, could be highly promising materials of choice for CdS/CdTe based heterojunction solar cell.
{"title":"Enhancement of the performance of CdS/CdTe heterojunction solar cell using TiO2/ZnO bi-layer ARC and V2O5 BSF layers: A simulation approach","authors":"A. Kuddus, Md. Ferdous Rahman, J. Hossain, A. Ismail","doi":"10.1051/epjap/2020200213","DOIUrl":"https://doi.org/10.1051/epjap/2020200213","url":null,"abstract":"This article presents the role of Bi-layer anti-reflection coating (ARC) of TiO2 /ZnO and back surface field (BSF) of V2 O5 for improving the photovoltaic performance of Cadmium Sulfide (CdS) and Cadmium Telluride (CdTe) based heterojunction solar cells (HJSCs). The simulation was performed at different concentrations, thickness, defect densities of each active materials and working temperatures to optimize the most excellent structure and working conditions for achieving the highest cell performance using obtained optical and electrical parameters value from the experimental investigation on spin-coated CdS, CdTe, ZnO, TiO2 and V2 O5 thin films deposited on the glass substrate. The simulation results reveal that the designed CdS/CdTe based heterojunction cell offers the highest efficiency, η of ∼25% with an enhanced open-circuit voltage, V oc of 0.811 V, short circuit current density, J sc of 38.51 mA cm−2 , fill factor, FF of 80% with bi-layer ARC and BSF. Moreover, it appears that the TiO2 /ZnO bi-layer ARC, as well as ETL and V2 O5 as BSF, could be highly promising materials of choice for CdS/CdTe based heterojunction solar cell.","PeriodicalId":12228,"journal":{"name":"European Physical Journal-applied Physics","volume":"41 1","pages":"20901"},"PeriodicalIF":1.0,"publicationDate":"2020-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79666172","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}
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