Abstract In this paper we investigated from rheological point of view some samples of ferrofluid-based magnetorheological fluids (FF-MRFs) with different volumic fractions of Fe microparticles, but with the same ferrofluid used as carrier liquid. We correlated the dimensionless flow curves, measured at different values of the magnetic field induction, using either Mason number or Casson number. It has been shown that in this approach, data sets measured under different conditions collapse on a single curve. This master curve is useful for controlling the concentration of Fe particles, so that the magnetic and magnetorheological properties of FF-MRF to be adapted to obtain high-performance applications.
{"title":"Correlation of Rheological Properties of Ferrofluid-Based Magnetorheological Fluids Using Some Dimensionless Numbers Defined in Magnetorheology","authors":"Gheorghe-Orlando Vălu, D. Susan-Resiga","doi":"10.2478/awutp-2021-0009","DOIUrl":"https://doi.org/10.2478/awutp-2021-0009","url":null,"abstract":"Abstract In this paper we investigated from rheological point of view some samples of ferrofluid-based magnetorheological fluids (FF-MRFs) with different volumic fractions of Fe microparticles, but with the same ferrofluid used as carrier liquid. We correlated the dimensionless flow curves, measured at different values of the magnetic field induction, using either Mason number or Casson number. It has been shown that in this approach, data sets measured under different conditions collapse on a single curve. This master curve is useful for controlling the concentration of Fe particles, so that the magnetic and magnetorheological properties of FF-MRF to be adapted to obtain high-performance applications.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"15 1","pages":"129 - 144"},"PeriodicalIF":0.0,"publicationDate":"2021-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89783165","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}
Beloufa Nabil, I. Ouadha, Cherchab Youcef, S. Louhibi-Fasla, Bekheira Samir, Hocine Kamel, Baida Abdelbasset
Abstract The structural, electronic and optical properties of the of ScxGa1-xP alloys have been investigated by using the full-potential plane-wave FP-LAPW method as implemented in the Wien2k code. The exchange-correlation (XC) energy of electrons was treated using the Perdewe-Burke-Ernzerhof parametrization (PBEGGA), and the Tran-Blaha modified Beck-Johnson potential (TB–mBJ). The lattice constant and the bulk modulus have been calculated and analyzed where a deviation from Végard’s law is observed for both. The calculation of the band structure of binary GaP shows that there is an indirect gap of 2.27 eV, while for the ScxGa1-xP compounds there are direct gaps with values of 1.91 eV, 1, 39 eV, 2.04 eV and 1.849 eV for x = 0.25, 0.5, 0, 75 and 1, respectively. At ambient pressure, the refractive index and the dielectric constant are in good agreement with the experimental results. The extinction coefficient does not begin to increase until a threshold, which represents the optical gap. This threshold is equal to 1.224 eV and it starts to increase to reach a maximum at an energy of 3.551 eV.
{"title":"Structural, Electronic and Optical Properties of ScxGa1-xP Alloys An: Ab Initio Study","authors":"Beloufa Nabil, I. Ouadha, Cherchab Youcef, S. Louhibi-Fasla, Bekheira Samir, Hocine Kamel, Baida Abdelbasset","doi":"10.2478/awutp-2021-0008","DOIUrl":"https://doi.org/10.2478/awutp-2021-0008","url":null,"abstract":"Abstract The structural, electronic and optical properties of the of ScxGa1-xP alloys have been investigated by using the full-potential plane-wave FP-LAPW method as implemented in the Wien2k code. The exchange-correlation (XC) energy of electrons was treated using the Perdewe-Burke-Ernzerhof parametrization (PBEGGA), and the Tran-Blaha modified Beck-Johnson potential (TB–mBJ). The lattice constant and the bulk modulus have been calculated and analyzed where a deviation from Végard’s law is observed for both. The calculation of the band structure of binary GaP shows that there is an indirect gap of 2.27 eV, while for the ScxGa1-xP compounds there are direct gaps with values of 1.91 eV, 1, 39 eV, 2.04 eV and 1.849 eV for x = 0.25, 0.5, 0, 75 and 1, respectively. At ambient pressure, the refractive index and the dielectric constant are in good agreement with the experimental results. The extinction coefficient does not begin to increase until a threshold, which represents the optical gap. This threshold is equal to 1.224 eV and it starts to increase to reach a maximum at an energy of 3.551 eV.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"230 1","pages":"111 - 128"},"PeriodicalIF":0.0,"publicationDate":"2021-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89436134","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. M. Alani, Abidoye L. Kolawole, A. O. Olalekan, Olatona G. Ismail
Abstract Leachate collected at the bottom of dead bird’s disposal pits may leak and migrate to pollute groundwater when soils and rocks present are porous. This study assessed the coefficient of permeability (K) and porosity (Ф) of soils and rocks in poultry farmland using 2 Dimensional (2D) electrical resistivity method and soil analysis. Geo-electrical data collection was achieved by using the dipole-dipole array. The field resistivity measurement was carried out along three traverse lines (three Profiles) of 100 m long which were oriented along with East-West directions. These measurements were taken in the order of increasing in offset distance interval of 5 m. The acquired apparent resistivity data were inverted using DIPPROWIN modeling software to perform 2D data inversion. Five soil samples from different locations at depths of 0 – 15 cm and 15 – 30 cm, on the poultry farmland, were collected, transported, and tested in the laboratory. K and Ф were determined using falling head and density methods respectively. The results obtained from the processed field resistivity data from the three profiles were presented as field data pseudo-sections, theoretical pseudo-section, and 2D resistivity structures. The 2D resistivity structure revealed three structures viz; highly conductive, slightly conductive, and resistive. The resistivity values of these structures ranged from 14.1-99.0 Ω m, 100-848 Ω m, and 1350-90330 Ω m respectively. The highly conductive structures were found in profiles 1 and 3 due to the downward migration of the contaminants from the dead bird disposal pit 1 and the feces disposal site through clayey sand soil. This occurs at the depth range of few meters from the surface to greater than 20 m. The presence of the slightly conductive structure is a result of filtration of the contaminants by the soil materials which increased the resistivity of the soil. The movement of the contaminant through the soil is an indication of the porous and permeable nature of the farmland. The resistive structure is only noticeable in profiles 1 and 2 but very prominent at the depth range of 5 m to more than 20 m and 5 m to 35 m along the profile length. The results of the analysis of the five soil samples from the poultry farmland showed a high value of 0.552 and 3.554 x 10−2cm/s of porosity (Ф) and coefficient of permeability (K) respectively. A strong correlation of R2 = 0.9878 existed between Ф and K. With these results geo-electrical method had successfully assessed Ф and K of the soil of the poultry farmland.
{"title":"Geo-Electrical Method of Assessment of Coefficient of Permeability and Porosity of Soil of a Poultry Farmland","authors":"F. M. Alani, Abidoye L. Kolawole, A. O. Olalekan, Olatona G. Ismail","doi":"10.2478/awutp-2021-0007","DOIUrl":"https://doi.org/10.2478/awutp-2021-0007","url":null,"abstract":"Abstract Leachate collected at the bottom of dead bird’s disposal pits may leak and migrate to pollute groundwater when soils and rocks present are porous. This study assessed the coefficient of permeability (K) and porosity (Ф) of soils and rocks in poultry farmland using 2 Dimensional (2D) electrical resistivity method and soil analysis. Geo-electrical data collection was achieved by using the dipole-dipole array. The field resistivity measurement was carried out along three traverse lines (three Profiles) of 100 m long which were oriented along with East-West directions. These measurements were taken in the order of increasing in offset distance interval of 5 m. The acquired apparent resistivity data were inverted using DIPPROWIN modeling software to perform 2D data inversion. Five soil samples from different locations at depths of 0 – 15 cm and 15 – 30 cm, on the poultry farmland, were collected, transported, and tested in the laboratory. K and Ф were determined using falling head and density methods respectively. The results obtained from the processed field resistivity data from the three profiles were presented as field data pseudo-sections, theoretical pseudo-section, and 2D resistivity structures. The 2D resistivity structure revealed three structures viz; highly conductive, slightly conductive, and resistive. The resistivity values of these structures ranged from 14.1-99.0 Ω m, 100-848 Ω m, and 1350-90330 Ω m respectively. The highly conductive structures were found in profiles 1 and 3 due to the downward migration of the contaminants from the dead bird disposal pit 1 and the feces disposal site through clayey sand soil. This occurs at the depth range of few meters from the surface to greater than 20 m. The presence of the slightly conductive structure is a result of filtration of the contaminants by the soil materials which increased the resistivity of the soil. The movement of the contaminant through the soil is an indication of the porous and permeable nature of the farmland. The resistive structure is only noticeable in profiles 1 and 2 but very prominent at the depth range of 5 m to more than 20 m and 5 m to 35 m along the profile length. The results of the analysis of the five soil samples from the poultry farmland showed a high value of 0.552 and 3.554 x 10−2cm/s of porosity (Ф) and coefficient of permeability (K) respectively. A strong correlation of R2 = 0.9878 existed between Ф and K. With these results geo-electrical method had successfully assessed Ф and K of the soil of the poultry farmland.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"110 1 1","pages":"88 - 110"},"PeriodicalIF":0.0,"publicationDate":"2021-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81892536","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}
M’hammed Benali Benadjemia, M. Lounis, M. Miloudi, N. Beloufa
Abstract This paper contains experimental research to minimize the basic limits of the SnO2 semiconductor oxide gas sensor. The operating temperature is high. In addition, their selectivity diminishes with gasses having the same chemical behavior. An experimental methodology is presented to overcome the difficulties of these metal oxides. The efficiency of the gas sensors made of Ag continuously doped at room temperature is excellent. At the end of the testing processes and security measures supplied, laboratory tests and experiments will be conducted to guarantee the acceptability of the planned study.
{"title":"Ag Continuous Doped SnO2 Sensor Selective to Co2 in Presence of Ethanol at Room Temperature","authors":"M’hammed Benali Benadjemia, M. Lounis, M. Miloudi, N. Beloufa","doi":"10.2478/awutp-2021-0006","DOIUrl":"https://doi.org/10.2478/awutp-2021-0006","url":null,"abstract":"Abstract This paper contains experimental research to minimize the basic limits of the SnO2 semiconductor oxide gas sensor. The operating temperature is high. In addition, their selectivity diminishes with gasses having the same chemical behavior. An experimental methodology is presented to overcome the difficulties of these metal oxides. The efficiency of the gas sensors made of Ag continuously doped at room temperature is excellent. At the end of the testing processes and security measures supplied, laboratory tests and experiments will be conducted to guarantee the acceptability of the planned study.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"33 1","pages":"72 - 87"},"PeriodicalIF":0.0,"publicationDate":"2021-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85717561","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}
A. Kadari, A. N. Ech-Chergui, M. Mohamedi, A. Zoukel, Tair Sabrina, Adjdir Mehdi, K. Driss-Khodja, B. Amrani
Abstract Pure and Al-doped ZnO thin films were successfully deposited with sol-gel dip coating on both substrates Si (100) and glass. The structural, chemical, morphological and optical properties as a function of the annealing temperature and dopant atomic concentration were investigated by means of X-ray diffraction, Energy dispersive X-ray, Scanning Electron Microscopy, and spectrophotometry. All the pure and doped films show a polycrystalline nature and hexagonal in structure. Accurate doping was proven by EDX. In addition, the SEM analysis revealed that the films possess uniform distribution throughout the surface and the grain dimension decreases with Al doping. From the transmittance measurements, it is see that all films are over 55% in the visible region and the band gap energy increases from 3.28 to 3.45 eV with the increase of Al concentration.
{"title":"Structural, Chemical and Optical Properties of Pure and Al-Doped Zno Thin Films Derived by Sol–Gel Dip Coating Process","authors":"A. Kadari, A. N. Ech-Chergui, M. Mohamedi, A. Zoukel, Tair Sabrina, Adjdir Mehdi, K. Driss-Khodja, B. Amrani","doi":"10.2478/awutp-2021-0005","DOIUrl":"https://doi.org/10.2478/awutp-2021-0005","url":null,"abstract":"Abstract Pure and Al-doped ZnO thin films were successfully deposited with sol-gel dip coating on both substrates Si (100) and glass. The structural, chemical, morphological and optical properties as a function of the annealing temperature and dopant atomic concentration were investigated by means of X-ray diffraction, Energy dispersive X-ray, Scanning Electron Microscopy, and spectrophotometry. All the pure and doped films show a polycrystalline nature and hexagonal in structure. Accurate doping was proven by EDX. In addition, the SEM analysis revealed that the films possess uniform distribution throughout the surface and the grain dimension decreases with Al doping. From the transmittance measurements, it is see that all films are over 55% in the visible region and the band gap energy increases from 3.28 to 3.45 eV with the increase of Al concentration.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"76 1","pages":"57 - 71"},"PeriodicalIF":0.0,"publicationDate":"2021-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85374903","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}
Abstract Contaminants from waste dumpsites have become sources of concern. Disposed wastes (Heavy metal) from battery industries could contaminate soil, agricultural plants, and groundwater. Therefore, this study aimed at the determination of the migration of heavy metal (Lead) from a Battery Waste Dumpsite using the electrical resistivity method. Using Schlumberger array, fifteen (15) Vertical Electrical Soundings (VES) were carried out around a Battery Waste Dumpsite in Ori –Ile, Ikumapaiyi at Olodo community, Ibadan, Oyo State, Nigeria. Preliminary analyses of VES data were performed and were fed into software (WINRESIST 1.0) for qualitative interpretation to reveal apparent resistivity values, the number of layers, and thickness. Three and four layers of topsoil, sandy-clayed, weathered/fractured basement, and basement were obtained. Various values of lowest apparent resistivity and depths of penetration of leached lead on the four sides of the battery waste dumpsite were obtained. The lowest apparent resistivity values obtained were converted to apparent conductivity and plotted against the distance of each VES point. Five collected water samples from available hand-dug wells around the dumpsite were analyzed for the presence of lead using an Atomic Absorption Spectrometer. Graph of apparent conductivity against VES distance indicated a decrease in conductivities with distance, an indication of reduction of Concentration of lead with distance. The level of Lead ranged from 0.081 to 0.770 mg/L which was above the tolerance level of 0.01 mg/L of WHO and SON, an indication of heavy metal pollution in groundwater. This study has established that lead ions were present in groundwater and had spread to a distance of 80 m from the battery waste dumpsite and were more pronounced on the southern region of the dumpsite.
{"title":"Determination of the Spread of Heavy Metal from Ori-Ile Battery Waste Dumpsite Using Electrical Resistivity Method","authors":"M. A. Fakunle, J. Adegoke, Joseph O. Enemali","doi":"10.2478/awutp-2021-0003","DOIUrl":"https://doi.org/10.2478/awutp-2021-0003","url":null,"abstract":"Abstract Contaminants from waste dumpsites have become sources of concern. Disposed wastes (Heavy metal) from battery industries could contaminate soil, agricultural plants, and groundwater. Therefore, this study aimed at the determination of the migration of heavy metal (Lead) from a Battery Waste Dumpsite using the electrical resistivity method. Using Schlumberger array, fifteen (15) Vertical Electrical Soundings (VES) were carried out around a Battery Waste Dumpsite in Ori –Ile, Ikumapaiyi at Olodo community, Ibadan, Oyo State, Nigeria. Preliminary analyses of VES data were performed and were fed into software (WINRESIST 1.0) for qualitative interpretation to reveal apparent resistivity values, the number of layers, and thickness. Three and four layers of topsoil, sandy-clayed, weathered/fractured basement, and basement were obtained. Various values of lowest apparent resistivity and depths of penetration of leached lead on the four sides of the battery waste dumpsite were obtained. The lowest apparent resistivity values obtained were converted to apparent conductivity and plotted against the distance of each VES point. Five collected water samples from available hand-dug wells around the dumpsite were analyzed for the presence of lead using an Atomic Absorption Spectrometer. Graph of apparent conductivity against VES distance indicated a decrease in conductivities with distance, an indication of reduction of Concentration of lead with distance. The level of Lead ranged from 0.081 to 0.770 mg/L which was above the tolerance level of 0.01 mg/L of WHO and SON, an indication of heavy metal pollution in groundwater. This study has established that lead ions were present in groundwater and had spread to a distance of 80 m from the battery waste dumpsite and were more pronounced on the southern region of the dumpsite.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"64 2 1","pages":"26 - 39"},"PeriodicalIF":0.0,"publicationDate":"2021-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77306008","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}
N. Beloufa, Youcef Chechab, S. Louhibi-Fasla, A. Chahed, S. Bekheira, H. Rekab-Djabri, S. Daoud
Abstract We use FP-LAPW method to study structural, electronic, and optical properties of the pure and Y-doped SnO2. The results show that by Y doping of SnO2 the band gaps are broadened, and still direct at Γ-point. For pure SnO2 material, the obtained values of the direct band gap are 0.607 eV for GGA-PBE and 2.524 eV for GGATB-mBJ, respectively. This later is in good agreement with the experimental data and other theoretical results. The Fermi level shifts into the valence band and exhibits p-type semiconductor character owing mainly from the orbital 4d-Y. Additionally, the calculated optical properties reveal that all concentrations are characterized by low reflectivity and absorption via wavelength λ (nm) in the visible light and near-infrared (NIR) ranges, which leads to a redshift in the optical transparency.
{"title":"First-Principles Calculations of the Structural, Electronic and Optical Properties of Yttrium-Doped SnO2","authors":"N. Beloufa, Youcef Chechab, S. Louhibi-Fasla, A. Chahed, S. Bekheira, H. Rekab-Djabri, S. Daoud","doi":"10.2478/awutp-2021-0004","DOIUrl":"https://doi.org/10.2478/awutp-2021-0004","url":null,"abstract":"Abstract We use FP-LAPW method to study structural, electronic, and optical properties of the pure and Y-doped SnO2. The results show that by Y doping of SnO2 the band gaps are broadened, and still direct at Γ-point. For pure SnO2 material, the obtained values of the direct band gap are 0.607 eV for GGA-PBE and 2.524 eV for GGATB-mBJ, respectively. This later is in good agreement with the experimental data and other theoretical results. The Fermi level shifts into the valence band and exhibits p-type semiconductor character owing mainly from the orbital 4d-Y. Additionally, the calculated optical properties reveal that all concentrations are characterized by low reflectivity and absorption via wavelength λ (nm) in the visible light and near-infrared (NIR) ranges, which leads to a redshift in the optical transparency.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"1 1","pages":"40 - 56"},"PeriodicalIF":0.0,"publicationDate":"2021-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78793370","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}
A. Gahtar, S. Benramache, A. Ammari, A. Boukhachem
Abstract Nickel sulfide (NiS) thin film has been deposited on glass substrates by spray-pyrolysis at 325 ± 5 °C. The precursor aqueous solution was synthetized using hexahydrated nickel nitrates and thiourea. The structural, morphological, optical and electrical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy and four probes electrical measurements. The XRD analysis confirmed the hexagonal structure of NiS thin film, which was found to crystalize along [010] direction with an average crystallites size of 10.5 nm. The lattice parameters are a = b = 3.420 Å and c = 5.300 Å in the space group P63/mmc. The optical properties of the films were investigated through the transmittance and the reflectance measurements. The results revealed that the material exhibits a direct optical band gap of 1.03 eV. The elementary composition analysis confirmed the presence of Ni and S with a stoichiometry ratio (Ni/S) of 1.05. The morphology analysis revealed a homogenous crack-free, compact appearance and a granular surface in all scanned areas. The average roughness of the surface was 6.48 nm. On the other hand, the film exhibits a high electrical conductivity ca. 1.10 × 105 S/cm at room temperature. The above results show that the prepared NiS in this study has a good crystallization, dense morphology, good stoichiometric ratio and high conductivity; therefore, it stands as a potential candidate for application in supercapacitors as an electrode material.
采用325±5℃的喷雾热解法在玻璃衬底上沉积了硫化镍(NiS)薄膜。以六水合硝酸镍和硫脲为原料合成前驱体水溶液。采用x射线衍射(XRD)、扫描电镜(SEM)、紫外可见光谱(UV-visible spectroscopy)和四探针电学测量对其结构、形态、光学和电学性能进行了表征。XRD分析证实了NiS薄膜的六方结构，发现其沿[010]方向结晶，平均晶粒尺寸为10.5 nm。在P63/mmc空间群中，晶格参数为a = b = 3.420 Å， c = 5.300 Å。通过透射率和反射率测量研究了薄膜的光学特性。结果表明，该材料的直接光学带隙为1.03 eV。元素组成分析证实了Ni和S的存在，化学计量比(Ni/S)为1.05。形貌分析显示，在所有扫描区域均为均匀无裂纹，紧凑的外观和颗粒状表面。表面平均粗糙度为6.48 nm。另一方面，薄膜在室温下表现出较高的电导率，约为1.10 × 105 S/cm。上述结果表明，本研究制备的NiS具有良好的结晶性、致密的形貌、良好的化学计量比和较高的电导率;因此，它作为一种潜在的候选材料应用于超级电容器作为电极材料。
{"title":"Study of the Structural, Optical, Electrical and Morphological Properties of Nickel Sulfide Thin Films Used in Supercapacitors","authors":"A. Gahtar, S. Benramache, A. Ammari, A. Boukhachem","doi":"10.2478/awutp-2021-0001","DOIUrl":"https://doi.org/10.2478/awutp-2021-0001","url":null,"abstract":"Abstract Nickel sulfide (NiS) thin film has been deposited on glass substrates by spray-pyrolysis at 325 ± 5 °C. The precursor aqueous solution was synthetized using hexahydrated nickel nitrates and thiourea. The structural, morphological, optical and electrical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy and four probes electrical measurements. The XRD analysis confirmed the hexagonal structure of NiS thin film, which was found to crystalize along [010] direction with an average crystallites size of 10.5 nm. The lattice parameters are a = b = 3.420 Å and c = 5.300 Å in the space group P63/mmc. The optical properties of the films were investigated through the transmittance and the reflectance measurements. The results revealed that the material exhibits a direct optical band gap of 1.03 eV. The elementary composition analysis confirmed the presence of Ni and S with a stoichiometry ratio (Ni/S) of 1.05. The morphology analysis revealed a homogenous crack-free, compact appearance and a granular surface in all scanned areas. The average roughness of the surface was 6.48 nm. On the other hand, the film exhibits a high electrical conductivity ca. 1.10 × 105 S/cm at room temperature. The above results show that the prepared NiS in this study has a good crystallization, dense morphology, good stoichiometric ratio and high conductivity; therefore, it stands as a potential candidate for application in supercapacitors as an electrode material.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88018365","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}
Abstract The search for a new material with unparalleled properties has attracted the interest of the scientific community due to rapid development of technology and it can be very inspiring to the future experiments. In this paper, electronic structure and optical properties of the new rare earth coinage-metal chalconegides YCuChO (Ch=S, Se, Te) are investigated in detail using state-of-the art density functional theory (DFT). Both the GGA-PBEsol and TB-mBJ functionals were used to describe the exchange-correlation interactions. These compounds are novel and have not been synthesized before. The optimized structural parameters, viz., lattice parameters and atomic position coordinates, are predicted. The analyses of the electronic properties indicate that the studied compounds are wide direct bandgap semiconductors. The calculated bandgaps varying from 1.69 eV (for the Te compound) to 2.5 eV (for the S compound) with the mBJ approach. Moreover, the optical properties of these compounds were comprehensively studied and discussed in terms of the dielectric function and loss function. The results provide theoretical support for the exploration of YCuChO (Ch=S, Se, Te) materials in potential optoelectronic applications.
由于技术的迅速发展，寻找一种具有无与伦比性能的新材料引起了科学界的兴趣，对未来的实验具有很大的启发作用。本文利用密度泛函理论(DFT)研究了新型稀土铸币金属chalconides YCuChO (Ch=S, Se, Te)的电子结构和光学性质。GGA-PBEsol和TB-mBJ两种功能都被用来描述交换相关相互作用。这些化合物是新的，以前没有合成过。预测了优化后的结构参数，即晶格参数和原子位置坐标。电子性质分析表明，所研究的化合物是宽直接带隙半导体。用mBJ方法计算得到的带隙从1.69 eV (Te化合物)到2.5 eV (S化合物)不等。此外，还从介电函数和损耗函数的角度对这些化合物的光学性质进行了全面的研究和讨论。研究结果为探索YCuChO (Ch=S, Se, Te)材料在光电领域的潜在应用提供了理论支持。
{"title":"Investigation of Electronic and Optical Properties of Novel Oxychalcogenides by Density Functional Theory","authors":"S. Moufok, B. Amrani","doi":"10.2478/awutp-2020-0008","DOIUrl":"https://doi.org/10.2478/awutp-2020-0008","url":null,"abstract":"Abstract The search for a new material with unparalleled properties has attracted the interest of the scientific community due to rapid development of technology and it can be very inspiring to the future experiments. In this paper, electronic structure and optical properties of the new rare earth coinage-metal chalconegides YCuChO (Ch=S, Se, Te) are investigated in detail using state-of-the art density functional theory (DFT). Both the GGA-PBEsol and TB-mBJ functionals were used to describe the exchange-correlation interactions. These compounds are novel and have not been synthesized before. The optimized structural parameters, viz., lattice parameters and atomic position coordinates, are predicted. The analyses of the electronic properties indicate that the studied compounds are wide direct bandgap semiconductors. The calculated bandgaps varying from 1.69 eV (for the Te compound) to 2.5 eV (for the S compound) with the mBJ approach. Moreover, the optical properties of these compounds were comprehensively studied and discussed in terms of the dielectric function and loss function. The results provide theoretical support for the exploration of YCuChO (Ch=S, Se, Te) materials in potential optoelectronic applications.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"75 6 1","pages":"120 - 129"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77580064","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}
Abstract In this work, copper doped nickel oxide as the thin films have been elaborated by a spin coating method, the nickel chloride hexahydrate (0.8M) and copper (II) chloride dehydrate (Cu/Ni = 0, 2.15, 4.3, 8.6 and 12.9 At.%) were used to prepare the Cu doped NiO thin films. The Cu doped NiO thin films were heated at a crystallization temperature of 600 °C with 2 h. The obtained thin films by spin coater method have a film thickness in the order of 400 nm. The prepared Cu doped NiO thin films have a polycrystalline with cubic structure (200) peak was observed. The optical property shows that the prepared thin films have a transmittance of about 70 %. The Cu doped NiO thin films have minimum bandgap energy is 3.85 eV at 12.9 at.%, the thin film deposited at 8.6 at.% has the highest value of Urbach energy is 425 meV. The Cu doped NiO thin films have a high electrical conductivity of 8.6 at% it is 7 (Ω.cm)−1. The prepared Cu doped NiO thin film was suitable for gas sensing applications due to the existing phase and higher electrical conductivity.
{"title":"Study the Effect of Cu Doping on Optical and Structural Properties of NiO Thin Films","authors":"S. Benramache, B. Benhaoua, Hanane Guezzoun","doi":"10.2478/awutp-2020-0002","DOIUrl":"https://doi.org/10.2478/awutp-2020-0002","url":null,"abstract":"Abstract In this work, copper doped nickel oxide as the thin films have been elaborated by a spin coating method, the nickel chloride hexahydrate (0.8M) and copper (II) chloride dehydrate (Cu/Ni = 0, 2.15, 4.3, 8.6 and 12.9 At.%) were used to prepare the Cu doped NiO thin films. The Cu doped NiO thin films were heated at a crystallization temperature of 600 °C with 2 h. The obtained thin films by spin coater method have a film thickness in the order of 400 nm. The prepared Cu doped NiO thin films have a polycrystalline with cubic structure (200) peak was observed. The optical property shows that the prepared thin films have a transmittance of about 70 %. The Cu doped NiO thin films have minimum bandgap energy is 3.85 eV at 12.9 at.%, the thin film deposited at 8.6 at.% has the highest value of Urbach energy is 425 meV. The Cu doped NiO thin films have a high electrical conductivity of 8.6 at% it is 7 (Ω.cm)−1. The prepared Cu doped NiO thin film was suitable for gas sensing applications due to the existing phase and higher electrical conductivity.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"15 1","pages":"15 - 22"},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88177577","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}
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