Pub Date : 2023-09-01DOI: 10.12693/aphyspola.144.180
F. Sahin-Dinc
In the current study, the dynamic viscosity has been established by the preceding viscosity correlation equation in terms of thermo-occupancy function, Y h = Y h ( h, T ) , for three types of chemically differ-ent pure substances between 283.15–398.15 K and up to 100 MPa. The thermo-occupancy function, Y h = Y h ( h, T ) , comprises temperature T and hole (nano-void) fraction h = h ( P, T ) estimated by the Simha–Somcynsky equation of state through the published density data. The density fitting results were found by this report to be from 0.026 to 0.051%. The predictive dynamic viscosity of dialkyl carbonates, ethylene glycol dimethyl ethers, and di(2-ethylhexyl) sebacate was obtained with an overall uncertainty of 0.29%, 0.40%, and 0.38%, respectively. The effects of the optimized volumetric and rheological parameters on the compounds’ molecular structure and architecture were investigated. The increase in fraction h with an increasing temperature suggests a decrease in the rate of change in dynamic viscosity (viscoholibility) of the samples over a computed hole fraction range.
{"title":"Dynamic Viscosity of Some Lubricants in Terms of Local Nano-Void Fraction","authors":"F. Sahin-Dinc","doi":"10.12693/aphyspola.144.180","DOIUrl":"https://doi.org/10.12693/aphyspola.144.180","url":null,"abstract":"In the current study, the dynamic viscosity has been established by the preceding viscosity correlation equation in terms of thermo-occupancy function, Y h = Y h ( h, T ) , for three types of chemically differ-ent pure substances between 283.15–398.15 K and up to 100 MPa. The thermo-occupancy function, Y h = Y h ( h, T ) , comprises temperature T and hole (nano-void) fraction h = h ( P, T ) estimated by the Simha–Somcynsky equation of state through the published density data. The density fitting results were found by this report to be from 0.026 to 0.051%. The predictive dynamic viscosity of dialkyl carbonates, ethylene glycol dimethyl ethers, and di(2-ethylhexyl) sebacate was obtained with an overall uncertainty of 0.29%, 0.40%, and 0.38%, respectively. The effects of the optimized volumetric and rheological parameters on the compounds’ molecular structure and architecture were investigated. The increase in fraction h with an increasing temperature suggests a decrease in the rate of change in dynamic viscosity (viscoholibility) of the samples over a computed hole fraction range.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135686638","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 : 2023-09-01DOI: 10.12693/aphyspola.144.144
A. Gjevori, B. Ziberi
Titanium dioxide is well known as a photoactive material to be activated under ultraviolet irradiation and is either employed as a photocatalyst or exhibits superhydrophilic behavior after reducing the surface energy under illumination for self-cleaning or anti-fogging surfaces. For increasing the reactivity of the thin films under solar illumination, a reduced band gap is desired. Doping with transition metals or with nitrogen has been reported in the literature. However, the incorporation of nitrogen into the growing film is a much more complex process, which is presently not completely understood. TiO 2 thin layers were produced by ion beam sputter deposition, which should allow the usage of temperature-sensitive substrates. The deposition has been performed in the existing experimental setup, previously used for investigations on Ag and Ge thin film physical vapor deposition processes, where the influence of the sputtered and reflected particles and their accompanying energy flux on the grain size, surface morphology, and conductivity have been measured. By adjusting the geometry between the incident ion beam, the sputter target, and the substrate, independently from the primary ion energy and species, a controlled deposition of samples was possible. Conventional ion implantation was employed to implant either carbon or nitrogen ions below the surface for bandgap engineering. The resulting thin films have subsequently been investigated for optical properties, stoichiometry, structural properties, surface topography, and photoactivity. The aim was to find an optimized geometry and to determine the exact particle and energy flux necessary for these conditions. Thus, the process opens up for transfer or scaling when assuming future industrial applications.
{"title":"Photoactivity of Dopped TiO<sub>2</sub> Thin Films by Ion Sputter Deposition","authors":"A. Gjevori, B. Ziberi","doi":"10.12693/aphyspola.144.144","DOIUrl":"https://doi.org/10.12693/aphyspola.144.144","url":null,"abstract":"Titanium dioxide is well known as a photoactive material to be activated under ultraviolet irradiation and is either employed as a photocatalyst or exhibits superhydrophilic behavior after reducing the surface energy under illumination for self-cleaning or anti-fogging surfaces. For increasing the reactivity of the thin films under solar illumination, a reduced band gap is desired. Doping with transition metals or with nitrogen has been reported in the literature. However, the incorporation of nitrogen into the growing film is a much more complex process, which is presently not completely understood. TiO 2 thin layers were produced by ion beam sputter deposition, which should allow the usage of temperature-sensitive substrates. The deposition has been performed in the existing experimental setup, previously used for investigations on Ag and Ge thin film physical vapor deposition processes, where the influence of the sputtered and reflected particles and their accompanying energy flux on the grain size, surface morphology, and conductivity have been measured. By adjusting the geometry between the incident ion beam, the sputter target, and the substrate, independently from the primary ion energy and species, a controlled deposition of samples was possible. Conventional ion implantation was employed to implant either carbon or nitrogen ions below the surface for bandgap engineering. The resulting thin films have subsequently been investigated for optical properties, stoichiometry, structural properties, surface topography, and photoactivity. The aim was to find an optimized geometry and to determine the exact particle and energy flux necessary for these conditions. Thus, the process opens up for transfer or scaling when assuming future industrial applications.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135686641","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 : 2023-09-01DOI: 10.12693/aphyspola.144.197
U.P. Tyagi, P. Goswami
The ferromagnetic Weyl semimetals, such as Co3Sn2S2, feature pairs of Weyl points characterized by the opposite chiralities.We model this type of semimetals by the inversion symmetry protected and the time reversal symmetry broken Bloch Hamiltonian. It involves terms representing the tunnelling effect, exchange field corresponding to the ferromagnetic order, chirality index of Weyl points with related energy parameters, and the angle formed by the spin magnetic moments and the axis perpendicular to the system-plane. While for the in-plane spin moment order the Weyl nodes are absent at some points of the first Brillouin zone , the bands of opposite chirality non-linearly cross each other with band inversion at Weyl points for the spin moment order along the perpendicular axis. The absence of linearity implies that the system is unable to host massless Weyl fermions. We also show that, in the absence of the exchange field, the incidence of the circularly polarized radiation leads to the emergence of a novel state with broken time reversal symmetry.
{"title":"On Weyl Nodes in Ferromagnetic Weyl Semimetal","authors":"U.P. Tyagi, P. Goswami","doi":"10.12693/aphyspola.144.197","DOIUrl":"https://doi.org/10.12693/aphyspola.144.197","url":null,"abstract":"The ferromagnetic Weyl semimetals, such as Co3Sn2S2, feature pairs of Weyl points characterized by the opposite chiralities.We model this type of semimetals by the inversion symmetry protected and the time reversal symmetry broken Bloch Hamiltonian. It involves terms representing the tunnelling effect, exchange field corresponding to the ferromagnetic order, chirality index of Weyl points with related energy parameters, and the angle formed by the spin magnetic moments and the axis perpendicular to the system-plane. While for the in-plane spin moment order the Weyl nodes are absent at some points of the first Brillouin zone , the bands of opposite chirality non-linearly cross each other with band inversion at Weyl points for the spin moment order along the perpendicular axis. The absence of linearity implies that the system is unable to host massless Weyl fermions. We also show that, in the absence of the exchange field, the incidence of the circularly polarized radiation leads to the emergence of a novel state with broken time reversal symmetry.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135686644","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 : 2023-09-01DOI: 10.12693/aphyspola.144.150
R. Yao, X. Jia, X. Zhu, M. Zhang, Q. Wei
A new monoclinic carbon crystal with the space group C 2 /c was uncovered; its unit cell comprises 32 carbon (C32) atoms. This full sp 3 -bonded carbon phase is dynamically and mechanically stable. The results show that C 2 /c -C32 has excellent mechanical properties, with its shear modulus and Vickers hardness being 343 and 56 GPa, respectively. Based on the elastic anisotropic calculations, C 2 /c -C32 is confirmed to be an anisotropic material. Notably, C 2 /c -C32 has a direct band gap structure with a band gap of 2.50 eV.
{"title":"C2/c-C32: A New Superhard sp<sup>3</sup> Carbon Allotrope with Direct Band Gap","authors":"R. Yao, X. Jia, X. Zhu, M. Zhang, Q. Wei","doi":"10.12693/aphyspola.144.150","DOIUrl":"https://doi.org/10.12693/aphyspola.144.150","url":null,"abstract":"A new monoclinic carbon crystal with the space group C 2 /c was uncovered; its unit cell comprises 32 carbon (C32) atoms. This full sp 3 -bonded carbon phase is dynamically and mechanically stable. The results show that C 2 /c -C32 has excellent mechanical properties, with its shear modulus and Vickers hardness being 343 and 56 GPa, respectively. Based on the elastic anisotropic calculations, C 2 /c -C32 is confirmed to be an anisotropic material. Notably, C 2 /c -C32 has a direct band gap structure with a band gap of 2.50 eV.","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135686643","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 : 2023-09-01DOI: 10.12693/aphyspola.144.163
S. Limam, A. Guittoum, Z. Lounis-Mokrani, M. Hemous, N. Bendjedda
The monitoring of the alpha irradiation effect on the microstructural deformation of CR39 via the variation of free volumes has been studied. CR39 samples have been irradiated with alpha particles at fluencies Φ of 2 . 6 × 10 8 , 5 . 27 × 10 8 , 7 . 91 × 10 8 , 1 . 3 × 10 9 , 1 . 84 × 10 9 , and 3 . 6 × 10 9 α/ cm 2 . The samples have been investigated with positron annihilation lifetime spectroscopy and Doppler broadening spectroscopy. The analysis of positron annihilation spectra has shown a variation of the ortho-positronium component τ 3 and the parameters S and W as a function of the fluence Φ . This variation is related to a change in the size and number of free volumes, which is created via the evolution of chemical chains. From the values of τ 3 , the free volume radius has been estimated using the Tao–Eldrup model. Moreover, theoretical calculation of the radial dose distribution has been also performed using the Waligorski formulation to get the track core radius. After an etching of 5 min, the positron annihilation spectroscopy technique was again used to investigate the microstructural changes in etched samples subjected to alpha radiation. A clear variation of τ 3 , S and W parameters, and free volume radius has been noted when compared to the non-etched samples. topics:
{"title":"Studying Alpha Irradiated CR39 Using Positron Annihilation Spectroscopy","authors":"S. Limam, A. Guittoum, Z. Lounis-Mokrani, M. Hemous, N. Bendjedda","doi":"10.12693/aphyspola.144.163","DOIUrl":"https://doi.org/10.12693/aphyspola.144.163","url":null,"abstract":"The monitoring of the alpha irradiation effect on the microstructural deformation of CR39 via the variation of free volumes has been studied. CR39 samples have been irradiated with alpha particles at fluencies Φ of 2 . 6 × 10 8 , 5 . 27 × 10 8 , 7 . 91 × 10 8 , 1 . 3 × 10 9 , 1 . 84 × 10 9 , and 3 . 6 × 10 9 α/ cm 2 . The samples have been investigated with positron annihilation lifetime spectroscopy and Doppler broadening spectroscopy. The analysis of positron annihilation spectra has shown a variation of the ortho-positronium component τ 3 and the parameters S and W as a function of the fluence Φ . This variation is related to a change in the size and number of free volumes, which is created via the evolution of chemical chains. From the values of τ 3 , the free volume radius has been estimated using the Tao–Eldrup model. Moreover, theoretical calculation of the radial dose distribution has been also performed using the Waligorski formulation to get the track core radius. After an etching of 5 min, the positron annihilation spectroscopy technique was again used to investigate the microstructural changes in etched samples subjected to alpha radiation. A clear variation of τ 3 , S and W parameters, and free volume radius has been noted when compared to the non-etched samples. topics:","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135686637","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 : 2023-09-01DOI: 10.12693/aphyspola.144.154
A. Aydin, B. Dede
{"title":"Synthesis, Spectroscopic Characterization and DFT Calculations of a Novel Lanthanum Complex of Ferrocenyl Dithiophosphonate","authors":"A. Aydin, B. Dede","doi":"10.12693/aphyspola.144.154","DOIUrl":"https://doi.org/10.12693/aphyspola.144.154","url":null,"abstract":"","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135686640","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 : 2023-09-01DOI: 10.12693/aphyspola.144.137
P. Pfeffer
A tunneling transistor without heterojunction as a theoretical design, or more precisely controlled electron current transmission by barrier potential, is under consideration. The electrons from the conduction band of the source tunnel through the forbidden gap $E_g$ of the channel to the conduction band of the drain. The tunneling current $J$ calculations made at helium temperature for the example InAs-InAs-InAs, Au-GaSe-Au and Al-AlN-Al structures show that for a constant source-drain voltage, $V_C$, of several mV, changes in the gate voltage, $V_G$, applied to the channel within the voltage range of 0 - $E_g/$2e change $J$ by even 10 orders of magnitude. Unlike the existing solutions such as tunnel field-effect-transistor (TFET), the proposed device uses the change of $V_G$ (gate voltage), i.e. the change of the electrostatic potential in the channel, to modify the imaginary wave vector $k_z$ of tunnel current electrons. Consequently, the gate voltage controls the damping force of the electrons wave functions and thus the magnitude of the tunneling current, $J$. The effect of increasing temperature, T, on $J(V_G)$ relation was also tested. It was found that only in structures with a wide forbidden channel gap this effect is insignificant (at least up to T=300 K).
{"title":"Theoretical Model of a New Type Tunneling Transistor","authors":"P. Pfeffer","doi":"10.12693/aphyspola.144.137","DOIUrl":"https://doi.org/10.12693/aphyspola.144.137","url":null,"abstract":"A tunneling transistor without heterojunction as a theoretical design, or more precisely controlled electron current transmission by barrier potential, is under consideration. The electrons from the conduction band of the source tunnel through the forbidden gap $E_g$ of the channel to the conduction band of the drain. The tunneling current $J$ calculations made at helium temperature for the example InAs-InAs-InAs, Au-GaSe-Au and Al-AlN-Al structures show that for a constant source-drain voltage, $V_C$, of several mV, changes in the gate voltage, $V_G$, applied to the channel within the voltage range of 0 - $E_g/$2e change $J$ by even 10 orders of magnitude. Unlike the existing solutions such as tunnel field-effect-transistor (TFET), the proposed device uses the change of $V_G$ (gate voltage), i.e. the change of the electrostatic potential in the channel, to modify the imaginary wave vector $k_z$ of tunnel current electrons. Consequently, the gate voltage controls the damping force of the electrons wave functions and thus the magnitude of the tunneling current, $J$. The effect of increasing temperature, T, on $J(V_G)$ relation was also tested. It was found that only in structures with a wide forbidden channel gap this effect is insignificant (at least up to T=300 K).","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135686642","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 : 2023-08-01DOI: 10.12693/aphyspola.144.63
S. Doma, G. D. Roston, M.F. Ahmed, K.D. Sen
.
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{"title":"Confined Ground State of Beryllium Atom and Its Isoelectronic Ions","authors":"S. Doma, G. D. Roston, M.F. Ahmed, K.D. Sen","doi":"10.12693/aphyspola.144.63","DOIUrl":"https://doi.org/10.12693/aphyspola.144.63","url":null,"abstract":".","PeriodicalId":7164,"journal":{"name":"Acta Physica Polonica A","volume":"19 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85909967","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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