Diffusion is a natural or artificial process that governs many phenomena in nature. The most known diffusion is the Brownian or normal motion, where the mean-square-displacement of the tracer (diffusive particle among others) increases as the square-root of time. It is not the case, however, for complex systems, where the diffusion is rather slow, because at small-scales, these media present an heterogenous structure. This kind of slow motion is called subdiffusion, where the associated mean-square-displacement increases in time, with a non trivial exponent, alpha, whose value is between 0 and 1. In this review paper, we report on new trends dealing with the study of the anomalous diffusion in Condensed Matter Physics. The study is achieved using a theoretical approach that is based on a Generalized Langevin Equation. As particular crowded systems, we choose the so-called Pickering emulsions (oil-in-water), and we are interested in how the dispersed droplets (protected by small solid charged nanoparticles) can diffuse in the continuous phase (water). Dynamic study is accomplished through the mean-square-displacement and the velocity-autocorrelation-function. Finally, a comparison with Molecular Dynamics data is made.
{"title":"Lecture on the anomalous diffusion in Condensed Matter Physics","authors":"M. Benhamou","doi":"10.23647/ca.md20180730","DOIUrl":"https://doi.org/10.23647/ca.md20180730","url":null,"abstract":"Diffusion is a natural or artificial process that governs many phenomena in nature. The most known diffusion is the Brownian or normal motion, where the mean-square-displacement of the tracer (diffusive particle among others) increases as the square-root of time. It is not the case, however, for complex systems, where the diffusion is rather slow, because at small-scales, these media present an heterogenous structure. This kind of slow motion is called subdiffusion, where the associated mean-square-displacement increases in time, with a non trivial exponent, alpha, whose value is between 0 and 1. In this review paper, we report on new trends dealing with the study of the anomalous diffusion in Condensed Matter Physics. The study is achieved using a theoretical approach that is based on a Generalized Langevin Equation. As particular crowded systems, we choose the so-called Pickering emulsions (oil-in-water), and we are interested in how the dispersed droplets (protected by small solid charged nanoparticles) can diffuse in the continuous phase (water). Dynamic study is accomplished through the mean-square-displacement and the velocity-autocorrelation-function. Finally, a comparison with Molecular Dynamics data is made.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75341226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we present a non-linear model for the study of DNA denaturation transition. To this end, we assume that the double-strands DNA interact via a realistic generalized Morse potential that reproduces well the features of the real interaction. Using the Transfer Matrix Method, based on the resolution of a Schrödinger equation, we first determine exactly their solution, which are found to be bound states. Second, from an exact expression of the ground state, we compute the denaturation temperature and the free energy density, in terms of the parameters of the potential.Then, we calculate the contact probability, which is the probability to find the double-strands at a (finite) distance apart, from which we determine the behaviour of the mean-distance between DNA-strands.The main conclusion is that, the present analytical study reveals that the generalized Morse potential is a good candidate for the study of DNA denaturation
{"title":"Investigation of DNA denaturation from generalized Morse potential","authors":"R. El Kinani, H. Kaidi, M. Benhamou","doi":"10.23647/ca.md20180207","DOIUrl":"https://doi.org/10.23647/ca.md20180207","url":null,"abstract":"In this paper, we present a non-linear model for the study of DNA denaturation transition. To this end, we assume that the double-strands DNA interact via a realistic generalized Morse potential that reproduces well the features of the real interaction. Using the Transfer Matrix Method, based on the resolution of a Schrödinger equation, we first determine exactly their solution, which are found to be bound states. Second, from an exact expression of the ground state, we compute the denaturation temperature and the free energy density, in terms of the parameters of the potential.Then, we calculate the contact probability, which is the probability to find the double-strands at a (finite) distance apart, from which we determine the behaviour of the mean-distance between DNA-strands.The main conclusion is that, the present analytical study reveals that the generalized Morse potential is a good candidate for the study of DNA denaturation","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80317148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Draouil, L. Alvarez, J. Causse, V. Flaud, M. Zaibi, J. Bantignies, M. Oueslati, J. Cambedouzou
Single-walled carbon nanotubes are functionalized with copper hexacyanoferrate nanoparticles for the liquid-solid extraction of cesium from liquid waste and contaminated water. The functionalization process is followed mainly by x-ray photoemission spectroscopy. Indeed, determining the chemical environment around carbon or nitrogen atoms allows to evidence the formation of covalent bounding. In addition, the signatures of iron and copper ions give information on the effective growth of hexacyanoferrate nanoparticles. Furthermore, the cesium sorption mechanism is investigated by comparing the peak intensities associated to the response of potassium and cesium ions. Finally, based on the liquid chromatography analyzes, the sorption of cesium with the functionalized carbon supports is studied. The main results of this work are the demonstration of both a good selectivity of cesium trapping and a high sorption capacity by hybrid single-walled carbon nanotubes.
{"title":"Carbon nanotubes functionalized with copper hexacyanoferrate nanoparticles for a selective extraction of cesium from liquid waste","authors":"H. Draouil, L. Alvarez, J. Causse, V. Flaud, M. Zaibi, J. Bantignies, M. Oueslati, J. Cambedouzou","doi":"10.23647/CA.MD20180407","DOIUrl":"https://doi.org/10.23647/CA.MD20180407","url":null,"abstract":"Single-walled carbon nanotubes are functionalized with copper hexacyanoferrate nanoparticles for the liquid-solid extraction of cesium from liquid waste and contaminated water. The functionalization process is followed mainly by x-ray photoemission spectroscopy. Indeed, determining the chemical environment around carbon or nitrogen atoms allows to evidence the formation of covalent bounding. In addition, the signatures of iron and copper ions give information on the effective growth of hexacyanoferrate nanoparticles. Furthermore, the cesium sorption mechanism is investigated by comparing the peak intensities associated to the response of potassium and cesium ions. Finally, based on the liquid chromatography analyzes, the sorption of cesium with the functionalized carbon supports is studied. The main results of this work are the demonstration of both a good selectivity of cesium trapping and a high sorption capacity by hybrid single-walled carbon nanotubes.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82605422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we aim at an extensive study of the diffusion phenomenon of oil-droplets dispersed in water onto which are strongly adsorbed charged point-like particles (Pickering emulsions). This diffusion that originates from multiple collisions with the molecules of water, is anomalous, due to the presence of relatively strong correlations between the moving oil-droplets. Using Molecular Dynamic simulation, with a pair-potential of Sogami-Ise type, we first observe that the random walkers execute a normal diffusion, at intermediate time, followed by a slow diffusion (subdiffusion) we attribute to the presence of cages, formed by the nearest neighbors (traps). In the cage-regime, we find that the mean-square-displacement increases according to a time-power law, with an anomalous diffusion exponent between 0 and 1. The existence of a cage effect is shown also by computing the velocity auto-correlation function of the random walker. It is found that, in a cage, this function is governed by an underdamped (oscillatory) behavior, for strong densities and surface charges, and low-salt concentration. In the inverse situation, however, we observe that this correlation-function is rather overdamped (non-oscillatory). In the two cases, at large-time, this function fails according to a time-power law.
{"title":"Extensive study of cage effect and subdiffusion in Pickering emulsions using molecular dynamics simulations","authors":"S. El-moudny, M. Benhamou","doi":"10.23647/ca.md20182404","DOIUrl":"https://doi.org/10.23647/ca.md20182404","url":null,"abstract":"In this work, we aim at an extensive study of the diffusion phenomenon of oil-droplets dispersed in water onto which are strongly adsorbed charged point-like particles (Pickering emulsions). This diffusion that originates from multiple collisions with the molecules of water, is anomalous, due to the presence of relatively strong correlations between the moving oil-droplets. Using Molecular Dynamic simulation, with a pair-potential of Sogami-Ise type, we first observe that the random walkers execute a normal diffusion, at intermediate time, followed by a slow diffusion (subdiffusion) we attribute to the presence of cages, formed by the nearest neighbors (traps). In the cage-regime, we find that the mean-square-displacement increases according to a time-power law, with an anomalous diffusion exponent between 0 and 1. The existence of a cage effect is shown also by computing the velocity auto-correlation function of the random walker. It is found that, in a cage, this function is governed by an underdamped (oscillatory) behavior, for strong densities and surface charges, and low-salt concentration. In the inverse situation, however, we observe that this correlation-function is rather overdamped (non-oscillatory). In the two cases, at large-time, this function fails according to a time-power law.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87078215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have investigated in the framework of the envelope function approximation and taking into account the dependence of the electron effective mass on radius the energy of an electron inside a ZnTe/CdSecore/shell spherical quantum dot. In order to make the problem more realistic, we describe the conduction band-edge alignment between core and shell materials by a finite height barrier. By applying the Ritz variational principle the effect of the electric field on the electronic states was also examined. Our numerical results show the opportunity to control the energy states position of the charge carriers inside our core/shell nanostructures by controlling the size (core radius, shell thickness) of the nanostructure and the strength of the external electric field. #CORE/SHELL MATERIALS #NANOSTRUCTURES #QUANTUM DOTS #ELECTRIC FIELD
{"title":"ZnTe/CdSe type-II core/shell spherical quantum dot under an external electric field","authors":"A. Chafai","doi":"10.23647/ca.md20180504","DOIUrl":"https://doi.org/10.23647/ca.md20180504","url":null,"abstract":"We have investigated in the framework of the envelope function approximation and taking into account the dependence of the electron effective mass on radius the energy of an electron inside a ZnTe/CdSecore/shell spherical quantum dot. In order to make the problem more realistic, we describe the conduction band-edge alignment between core and shell materials by a finite height barrier. By applying the Ritz variational principle the effect of the electric field on the electronic states was also examined. Our numerical results show the opportunity to control the energy states position of the charge carriers inside our core/shell nanostructures by controlling the size (core radius, shell thickness) of the nanostructure and the strength of the external electric field. #CORE/SHELL MATERIALS #NANOSTRUCTURES #QUANTUM DOTS #ELECTRIC FIELD","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73729134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Ouaddi, A. Tirbiyine, A. Taoufik, Y. A. Ahmed, Fatiha Chiban, H. Chaib, A. Nafidi, S. Senoussi
We report investigations of the low temperature dc susceptibility and the magnetization on the layered organic superconductor k-(BEDT-TTF)2Cu[N(CN)2]Br near 80 K and the effect of disorder on the superconducting transition temperature Tc. The shielding effect (S) and the critical current density Jc were studied (with H parallel to the c axis of the crystal). Jc can be estimated by analysis of magnetic hysteresis measurement using the Bean model. For each temperature value, we observed two regimes in the critical current density Jc(H). Our results show that the magnetic properties of these compounds depend strongly on the cooling rate. The structural transformation which occurs at the vicinity of 80 K very strongly influences the physics of vortex lattice and the associated magnetic behavior. #organic_superconductor #critical_current #shielding_effect #magnetic_susceptibility #vortex_pinning
{"title":"Vortex phase transition and superconducting properties in quasi-two-dimensional k-(BEDT-TTF)2Cu[N(CN)2]Br organic superconductor","authors":"H. Ouaddi, A. Tirbiyine, A. Taoufik, Y. A. Ahmed, Fatiha Chiban, H. Chaib, A. Nafidi, S. Senoussi","doi":"10.23647/ca.md20181603","DOIUrl":"https://doi.org/10.23647/ca.md20181603","url":null,"abstract":"We report investigations of the low temperature dc susceptibility and the magnetization on the layered organic superconductor k-(BEDT-TTF)2Cu[N(CN)2]Br near 80 K and the effect of disorder on the superconducting transition temperature Tc. The shielding effect (S) and the critical current density Jc were studied (with H parallel to the c axis of the crystal). Jc can be estimated by analysis of magnetic hysteresis measurement using the Bean model. For each temperature value, we observed two regimes in the critical current density Jc(H). Our results show that the magnetic properties of these compounds depend strongly on the cooling rate. The structural transformation which occurs at the vicinity of 80 K very strongly influences the physics of vortex lattice and the associated magnetic behavior. #organic_superconductor #critical_current #shielding_effect #magnetic_susceptibility #vortex_pinning","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83955911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Fergani, S.M. Ait Abdelkader, H. Chadli, A. Rahmani, A. Rahmani
The vibrational properties of defective single-walled carbon nanotube filled with C60 fullerene is the subject of the current study. For this aim we use the spectral moments method in the framework of the bond-polarization theory to calculate the non-resonant Raman spectra of hexa-vacancy defective C60 peapods. Essentially, the vibrational properties are closely coupled with the atomic structure of the system. The evolution of the Raman spectrum as a function of the spatial arrangement of defects in carbon nanotubes is discussed. This work provides benchmark theoretical results to understand the experimental data of defective C60 peapods. #single_wall_carbon_nanotube #C60_peapods #hexa-vacancy_defect #Raman_spectroscopy #pectral_moment_method
{"title":"Raman active modes in defective peapods","authors":"F. Fergani, S.M. Ait Abdelkader, H. Chadli, A. Rahmani, A. Rahmani","doi":"10.23647/ca.md20180803","DOIUrl":"https://doi.org/10.23647/ca.md20180803","url":null,"abstract":"The vibrational properties of defective single-walled carbon nanotube filled with C60 fullerene is the subject of the current study. For this aim we use the spectral moments method in the framework of the bond-polarization theory to calculate the non-resonant Raman spectra of hexa-vacancy defective C60 peapods. Essentially, the vibrational properties are closely coupled with the atomic structure of the system. The evolution of the Raman spectrum as a function of the spatial arrangement of defects in carbon nanotubes is discussed. This work provides benchmark theoretical results to understand the experimental data of defective C60 peapods. #single_wall_carbon_nanotube #C60_peapods #hexa-vacancy_defect #Raman_spectroscopy #pectral_moment_method","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73886944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this theoretical work, the Raman spectra were analyzed by considering the origin of the G peak, its shape, position and relative intensity as a function of the number of graphene layers. By using the spectral moment’s method, the Raman spectra of mono, bi and few-layers of graphene are calculated and a good agreement was found with group theory concerning the number of the Raman-active modes and the Raman measurements. Our results provide a Raman analysis to evaluate the number of layers in multilayer graphene. #Raman_spectroscopy #graphene #graphite
{"title":"Identification of mono-and few-layer graphene: Raman study","authors":"M. Boutahir, A. Rahmani, H. Chadli, A. Rahmani","doi":"10.23647/ca.md20180503","DOIUrl":"https://doi.org/10.23647/ca.md20180503","url":null,"abstract":"In this theoretical work, the Raman spectra were analyzed by considering the origin of the G peak, its shape, position and relative intensity as a function of the number of graphene layers. By using the spectral moment’s method, the Raman spectra of mono, bi and few-layers of graphene are calculated and a good agreement was found with group theory concerning the number of the Raman-active modes and the Raman measurements. Our results provide a Raman analysis to evaluate the number of layers in multilayer graphene. #Raman_spectroscopy #graphene #graphite","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72762940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The symposium ISPDS2 has taken place in Meknes (Morocco) in October, 2017. It has gathered specialists of various fields who presented their work in connection with the problematics of data storage. This conference volume contains 75 abstracts of communications presented at the meeting as invited conferences, talks, or posters. Various topics are covered, as carbon nanotubes, SWCN, Domain walls, piezoelectrics, anomalous diffusion, electron microscopy, spectral moments, SiGe, nanocrystals, magneto-caloric, electro-caloric, ferrite, spinels, perovskites, graphene, solar cells, colossal magnetoresistance (CMR)
{"title":"2nd International Symposium on Physics of Data Storage; Conference Volume","authors":"Abdelhai Rahmani","doi":"10.23647/ca.md20172012","DOIUrl":"https://doi.org/10.23647/ca.md20172012","url":null,"abstract":"The symposium ISPDS2 has taken place in Meknes (Morocco) in October, 2017. It has gathered specialists of various fields who presented their work in connection with the problematics of data storage. This conference volume contains 75 abstracts of communications presented at the meeting as invited conferences, talks, or posters. Various topics are covered, as carbon nanotubes, SWCN, Domain walls, piezoelectrics, anomalous diffusion, electron microscopy, spectral moments, SiGe, nanocrystals, magneto-caloric, electro-caloric, ferrite, spinels, perovskites, graphene, solar cells, colossal magnetoresistance (CMR)","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81115360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
TEAM1 has taken place in Sete (France) on 4, 5, 6 july 2017. It has gathered a little less than 40 participants who presented communications on various fields of advanced materials, and on experimental facilities or experimental methods, that are briefly summarized in the present volume. Presented abstracts deal with fullerenes, graphene, thin films, oxides, ferroelectrics, pyroelectrics, piezoelectrics, superconductors, nanomaterials, photovoltaics, X-ray diffraction, electron diffraction, electron microscopy, electron holography, carbon nanotubes, nanorods, ZnO.
{"title":"Transpyrenean Encounter on Advanced Materials","authors":"P. Saint-Grégoire","doi":"10.23647/ca.md20170407","DOIUrl":"https://doi.org/10.23647/ca.md20170407","url":null,"abstract":"TEAM1 has taken place in Sete (France) on 4, 5, 6 july 2017. It has gathered a little less than 40 participants who presented communications on various fields of advanced materials, and on experimental facilities or experimental methods, that are briefly summarized in the present volume. Presented abstracts deal with fullerenes, graphene, thin films, oxides, ferroelectrics, pyroelectrics, piezoelectrics, superconductors, nanomaterials, photovoltaics, X-ray diffraction, electron diffraction, electron microscopy, electron holography, carbon nanotubes, nanorods, ZnO.","PeriodicalId":19388,"journal":{"name":"OAJ Materials and Devices","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85305776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：