Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad69e7
Abdulafeez O. Akorede, Adetutu O Aliyu, A. A. Adebisi
The efficiency of self-healing microcapsule in restoring damages incurred by polymeric or composite materials is heavily dependent on modelling of encapsulation conditions to achieve optimized microcapsule with desired characteristics. This study modelled the effects of encapsulation conditions (core–shell ratio, agitation rate, and temperature) on the morphological, chemical, and thermal characteristics of epoxy-polymethylmethacrylate (epoxy-PMMA) microcapsules using response surface methodology (RSM). Epoxy-PMMA microcapsules were synthesized by encapsulating epoxy resin in polymethylmethacrylate (PMMA) at varied encapsulation conditions using solvent evaporation method. The morphology of the synthesized microcapsule using optical microscope (OP) revealed that the microcapsules are either mononuclear or irregular capsule types. The modelled effect showed that microcapsule percentage yield varied between 74.96 to 96.56%, was highly influenced by core–shell ratio and the effect of studied encapsulation conditions on percentage yield was best described by quadratic model. The core content of the microcapsules varied between 54.8 to 67.2%, observed to be highly influenced by both core–shell ratio and agitation rate which fit into linear model. The microcapsule average diameter was between 26 to 74 μm, highly influenced by agitation rate and fit linear model. Fourier transform infrared (FTIR) spectra of synthesized microcapsules revealed epoxy characteristic peak of C–O–C at 913 cm−1 and C–O-ph stretching at 1032 cm−1. C–O doublet of PMMA was observed at 1386 cm−1 and 1189 cm−1. Thermogravimetric analysis (TGA) of epoxy-PMMA microcapsule showed three stages of decomposition attributed to water evaporation, epoxy degradation, and PMMA shell degradation. Lastly, optimization process to achieve maximum yield, maximum core content and minimum capsule diameter was obtained with core–shell ratio of 1.5:3 and agitation rate of 1000 rpm at 40 °C. The synthesized epoxy-PMMA microcapsules exhibited chemical, thermal, morphological stability and the models can be optimized to achieve microcapsule with desired characteristics.
{"title":"Modelling and optimization of epoxy-PMMA microcapsule synthesis parameter: A response surface methodology approach","authors":"Abdulafeez O. Akorede, Adetutu O Aliyu, A. A. Adebisi","doi":"10.1088/1402-4896/ad69e7","DOIUrl":"https://doi.org/10.1088/1402-4896/ad69e7","url":null,"abstract":"\u0000 The efficiency of self-healing microcapsule in restoring damages incurred by polymeric or composite materials is heavily dependent on modelling of encapsulation conditions to achieve optimized microcapsule with desired characteristics. This study modelled the effects of encapsulation conditions (core–shell ratio, agitation rate, and temperature) on the morphological, chemical, and thermal characteristics of epoxy-polymethylmethacrylate (epoxy-PMMA) microcapsules using response surface methodology (RSM). Epoxy-PMMA microcapsules were synthesized by encapsulating epoxy resin in polymethylmethacrylate (PMMA) at varied encapsulation conditions using solvent evaporation method. The morphology of the synthesized microcapsule using optical microscope (OP) revealed that the microcapsules are either mononuclear or irregular capsule types. The modelled effect showed that microcapsule percentage yield varied between 74.96 to 96.56%, was highly influenced by core–shell ratio and the effect of studied encapsulation conditions on percentage yield was best described by quadratic model. The core content of the microcapsules varied between 54.8 to 67.2%, observed to be highly influenced by both core–shell ratio and agitation rate which fit into linear model. The microcapsule average diameter was between 26 to 74 μm, highly influenced by agitation rate and fit linear model. Fourier transform infrared (FTIR) spectra of synthesized microcapsules revealed epoxy characteristic peak of C–O–C at 913 cm−1 and C–O-ph stretching at 1032 cm−1. C–O doublet of PMMA was observed at 1386 cm−1 and 1189 cm−1. Thermogravimetric analysis (TGA) of epoxy-PMMA microcapsule showed three stages of decomposition attributed to water evaporation, epoxy degradation, and PMMA shell degradation. Lastly, optimization process to achieve maximum yield, maximum core content and minimum capsule diameter was obtained with core–shell ratio of 1.5:3 and agitation rate of 1000 rpm at 40 °C. The synthesized epoxy-PMMA microcapsules exhibited chemical, thermal, morphological stability and the models can be optimized to achieve microcapsule with desired characteristics.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"31 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923102","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}
Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad6dad
marjan Jafari
Position dependent mass dissipative scalar field is a theoretical framework that combines the concepts of position-dependent mass and dissipative systems in the context of scalar field theory. In this framework, the mass of the scalar field is allowed to vary with position, leading to interesting physical phenomena such as non-locality and non-Hermiticity. We consider a generalized classical Lagrangian for the system and by developing a theoretical formulation, quantized system canonically. In follow, two-point correlation functions of the system is obtained at finite temperature and Free energy of the system is calculated in terms of Matsubara frequencies. This research can provide insights into the behavior of particles and fields in non-uniform environments, and has potential applications in various fields of physics.
{"title":"Position dependent mass dissipative scalar field at finite temperature","authors":"marjan Jafari","doi":"10.1088/1402-4896/ad6dad","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6dad","url":null,"abstract":"\u0000 Position dependent mass dissipative scalar field is a theoretical framework that combines the concepts of position-dependent mass and dissipative systems in the context of scalar field theory. In this framework, the mass of the scalar field is allowed to vary with position, leading to interesting physical phenomena such as non-locality and non-Hermiticity. We consider a generalized classical Lagrangian for the system and by developing a theoretical formulation, quantized system canonically. In follow, two-point correlation functions of the system is obtained at finite temperature and Free energy of the system is calculated in terms of Matsubara frequencies. This research can provide insights into the behavior of particles and fields in non-uniform environments, and has potential applications in various fields of physics.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"81 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922546","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}
Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad6daa
Hossein Taghipoor, Jaber Mirzaei
This paper aims to investigate the mechanical properties of bio-composites reinforced with basalt natural fibers/nanographene in polypropylene by incorporating pp-g-ma compatibilizer. The study employs the Response Surface Method with the Behnken box approach to formulate a novel mathematical model for bio-composite behavior based on the parameters of basalt fiber weight percentage, nanographene weight percentage, and PP-g-MA weight percentage. Unlike previous studies, our work uniquely integrates basalt fibers and nanographene to enhance tensile, bending, and impact strengths, achieving a composite with optimal mechanical properties. The performance of the research samples was evaluated through tensile, bending, and impact tests, with the results substantiated using Field Emission Scanning Electron Microscopy images. The failure surface in these samples revealed that the central mechanism influencing the performance of the introduced bio-composite is the failure of the fibers and their separation, accompanied by the stretching of the fibers from the base material. Subsequently, multi-objective optimization was conducted with the aim of increasing tensile strength, bending strength, and impact strength while reducing the weight of the samples. A Pareto diagram is presented based on the design goals. The outcomes indicate that the bio-composite sample values in the most suitable state for three mechanical characteristics including, tensile, impact, and bending strength are equal to 28, 90, and 49 MPa, respectively. This innovative combination and optimization significantly improve performance metrics, demonstrated through extensive testing and multi-objective optimization, which reveals the bio-composite's superior mechanical characteristics.
{"title":"Optimizing Mechanical Behavior in Polymer Bio-Composites Reinforced with Basalt, Graphene, and PP-g-MA","authors":"Hossein Taghipoor, Jaber Mirzaei","doi":"10.1088/1402-4896/ad6daa","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6daa","url":null,"abstract":"\u0000 This paper aims to investigate the mechanical properties of bio-composites reinforced with basalt natural fibers/nanographene in polypropylene by incorporating pp-g-ma compatibilizer. The study employs the Response Surface Method with the Behnken box approach to formulate a novel mathematical model for bio-composite behavior based on the parameters of basalt fiber weight percentage, nanographene weight percentage, and PP-g-MA weight percentage. Unlike previous studies, our work uniquely integrates basalt fibers and nanographene to enhance tensile, bending, and impact strengths, achieving a composite with optimal mechanical properties. The performance of the research samples was evaluated through tensile, bending, and impact tests, with the results substantiated using Field Emission Scanning Electron Microscopy images. The failure surface in these samples revealed that the central mechanism influencing the performance of the introduced bio-composite is the failure of the fibers and their separation, accompanied by the stretching of the fibers from the base material. Subsequently, multi-objective optimization was conducted with the aim of increasing tensile strength, bending strength, and impact strength while reducing the weight of the samples. A Pareto diagram is presented based on the design goals. The outcomes indicate that the bio-composite sample values in the most suitable state for three mechanical characteristics including, tensile, impact, and bending strength are equal to 28, 90, and 49 MPa, respectively. This innovative combination and optimization significantly improve performance metrics, demonstrated through extensive testing and multi-objective optimization, which reveals the bio-composite's superior mechanical characteristics.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"69 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922520","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}
Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad6da4
Guichard Djiodjo-Seugmo, Patenou Jean Baptiste, Calvin Tadmon
We consider a Petrov Type D physical metric g, an auxiliary metric q and a Chaplygin Gas of pressure P in Eddington-inspired-Born-Infeld theory. From the Eddington-inspired-Born-Infeld-Chaplygin Gas equations, we first derive a system of second order nonlinear ordinary differential equations. Then, by a suitable change of variables, we arrive at a system of first order linear ordinary differential equations for the non-vanishing components of the pressure P , the physical metric g and the auxiliary metric q. Thanks to the superposition method, we collect an analytical solution for the nonlinear system obtained, which allows to obtain new exact cosmological solutions for the model considered. By studying the Kretschmann invariant, we see a singularity exists at the origin of the cosmic time. By the Kruskal-like coordinates, we conclude that this solution is the counterpart of the Friedman-Lemaître Robertson-Walker spacetime in the Eddington-inspired-Born-Infeld theory. The Hubble and deceleration parameters in both directions of the physical metric g and the auxiliary metric q, as well as their behaviours over time, are also studied. The thermodynamic behaviour of the Chaplygin Gas model is investigated and, as a result, we show that the third-law of thermodynamics is verified. This means that the value of the entropy of the Chaplygin Gas in the perfect crystal state is zero at a temperature of zero Kelvin, which yields a determined value of the entropy and not an additive constant. Finally, we show that the solutions change asymptotically to the isotropic regime of expansion of Dark Energy. With this, we infer that the Chaplygin Gas can show a unified picture of Dark Energy and Dark Matter cooling during the expansion of the universe.
我们考虑爱丁顿-启发-伯恩-因菲尔德理论中的彼得罗夫 D 型物理度量 g、辅助度量 q 和压力为 P 的查普利金气体。根据爱丁顿启发-伯恩-因菲尔德-查普里金气体方程，我们首先推导出一个二阶非线性常微分方程系。然后，通过适当的变量变化，我们得到了压力 P、物理度量 g 和辅助度量 q 的非消失分量的一阶线性常微分方程系统。由于采用了叠加法，我们收集到了所得到的非线性系统的解析解，从而为所考虑的模型得到了新的精确宇宙学解。通过研究克雷奇曼不变量，我们发现在宇宙时间的原点存在一个奇点。通过类似克鲁斯卡尔的坐标，我们得出结论，这个解是爱丁顿启发-伯恩-因费尔德理论中弗里德曼-勒梅特尔-罗伯逊-沃克时空的对应物。此外，还研究了物理度量 g 和辅助度量 q 在两个方向上的哈勃参数和减速参数，以及它们随时间变化的行为。研究了查普利金气体模型的热力学行为，结果表明热力学第三定律得到了验证。这意味着在零开尔文温度下，完美晶体状态下的查普利金气体的熵值为零，这就产生了一个确定的熵值，而不是一个加常数。最后，我们展示了暗能量膨胀各向同性机制下的解的渐近变化。由此，我们推断查普利金气体可以展示宇宙膨胀过程中暗能量和暗物质冷却的统一图景。
{"title":"Exact cosmological solutions of a Chaplygin Gas in Anisotropic Petrov Type D Spacetimes in Eddington-inspired-Born-Infeld gravity: Dark Energy Model","authors":"Guichard Djiodjo-Seugmo, Patenou Jean Baptiste, Calvin Tadmon","doi":"10.1088/1402-4896/ad6da4","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da4","url":null,"abstract":"\u0000 We consider a Petrov Type D physical metric g, an auxiliary metric q and a Chaplygin Gas of pressure P in Eddington-inspired-Born-Infeld theory. From the Eddington-inspired-Born-Infeld-Chaplygin Gas equations, we first derive a system of second order nonlinear ordinary differential equations. Then, by a suitable change of variables, we arrive at a system of first order linear ordinary differential equations for the non-vanishing components of the pressure P , the physical metric g and the auxiliary metric q. Thanks to the superposition method, we collect an analytical solution for the nonlinear system obtained, which allows to obtain new exact cosmological solutions for the model considered. By studying the Kretschmann invariant, we see a singularity exists at the origin of the cosmic time. By the Kruskal-like coordinates, we conclude that this solution is the counterpart of the Friedman-Lemaître Robertson-Walker spacetime in the Eddington-inspired-Born-Infeld theory. The Hubble and deceleration parameters in both directions of the physical metric g and the auxiliary metric q, as well as their behaviours over time, are also studied. The thermodynamic behaviour of the Chaplygin Gas model is investigated and, as a result, we show that the third-law of thermodynamics is verified. This means that the value of the entropy of the Chaplygin Gas in the perfect crystal state is zero at a temperature of zero Kelvin, which yields a determined value of the entropy and not an additive constant. Finally, we show that the solutions change asymptotically to the isotropic regime of expansion of Dark Energy. With this, we infer that the Chaplygin Gas can show a unified picture of Dark Energy and Dark Matter cooling during the expansion of the universe.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"5 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922069","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}
Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad6da8
Parul Kansal, A. Mandpura, Narendra Kumar
A two port multiple input multiple output (MIMO) antenna with self-isolation is proposed for the application of fifth generation (5G) mobile phones. In this antenna, feeding ports that are inherently isolated across a bandwidth without the need for extra decoupling components directly excite the MIMO antenna. An approach involving the creation of common and differential modes utilizes a mode-cancellation technique to comprehensively understand the self-decoupling mechanism on a physical level. The proposed self-decoupled antenna pair exhibits about 22 dB isolation across the triple band 2.58 GHz to 2.84 GHz, 3.4 GHz to 3.9 GHz and 4.3 GHz to 4.6 GHz, respectively. According to the experimental findings, the proposed MIMO system may offer better than 22 dB isolation across all ports and a respectable level of overall gain 1.9 dBi, 3.77 dBi and 2.9 dBi across 2.58 GHz to 2.84 GHz, 3.4 GHz to 3.9 GHz and 4.3 GHz to 4.6 GHz. A suggested design method, with its advantages of self-decoupling, simple structure, high efficiency and triple band demonstrates amazing upcoming 5G highly integrated MIMO antennas for 5G devices.
{"title":"Triple Band Self-Decoupled MIMO Antenna Pair for 5G Communication","authors":"Parul Kansal, A. Mandpura, Narendra Kumar","doi":"10.1088/1402-4896/ad6da8","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da8","url":null,"abstract":"\u0000 A two port multiple input multiple output (MIMO) antenna with self-isolation is proposed for the application of fifth generation (5G) mobile phones. In this antenna, feeding ports that are inherently isolated across a bandwidth without the need for extra decoupling components directly excite the MIMO antenna. An approach involving the creation of common and differential modes utilizes a mode-cancellation technique to comprehensively understand the self-decoupling mechanism on a physical level. The proposed self-decoupled antenna pair exhibits about 22 dB isolation across the triple band 2.58 GHz to 2.84 GHz, 3.4 GHz to 3.9 GHz and 4.3 GHz to 4.6 GHz, respectively. According to the experimental findings, the proposed MIMO system may offer better than 22 dB isolation across all ports and a respectable level of overall gain 1.9 dBi, 3.77 dBi and 2.9 dBi across 2.58 GHz to 2.84 GHz, 3.4 GHz to 3.9 GHz and 4.3 GHz to 4.6 GHz. A suggested design method, with its advantages of self-decoupling, simple structure, high efficiency and triple band demonstrates amazing upcoming 5G highly integrated MIMO antennas for 5G devices.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"78 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922452","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}
Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad6da2
Phuc Hong Than, Tho Than, Yasushi Takaki
A novel design for a junction barrier Schottky (JBS) diode based on a p-GaN/n-Ga2O3 heterojunction is proposed, exhibiting superior static characteristics and a higher breakdown capability compared to the traditional Ga2O3 Schottky barrier diode (SBD). By utilizing wide-bandgap p-type GaN, the β-Ga2O3 JBS diodes demonstrate a turn-on voltage (Von) of approximately 0.8 V. Moreover, a breakdown voltage (Vbr) of 880 V and a specific on-resistance (Ron,sp) of 3.96 mΩ·cm2 are achieved, resulting in a Baliga’s figure of merit (BFOM) of approximately 0.2 GW/cm2. A forward current density of 465 A/cm2 at a forward voltage drop of 3 V is attained. The simulated reverse leakage current density remains low at 9.0 mA/cm2 at 800 V. Floating field rings, in conjunction with junction termination extension (JTE), were utilized as edge termination methods to attain a high breakdown voltage. The impact of β-Ga2O3 periodic fin width fluctuations on the electrical characteristics of JBS was investigated. Due to the enhanced sidewall depletion effect caused by p-type GaN, the forward current (IF) and reverse current (IR) decrease when the β-Ga2O3 periodic fin width decreases. The findings of this study indicate the remarkable promise of p-GaN/n-Ga2O3 JBS diodes for power device applications.
本文提出了一种基于 p-GaN/n-Ga2O3 异质结的新型结势垒肖特基二极管 (JBS) 设计，与传统的 Ga2O3 肖特基势垒二极管 (SBD) 相比，这种二极管具有更优越的静态特性和更高的击穿能力。通过利用宽带隙 p 型氮化镓，β-Ga2O3 JBS 二极管的导通电压 (Von) 约为 0.8 V。此外，击穿电压（Vbr）为 880 V，比导通电阻（Ron,sp）为 3.96 mΩ-cm2，巴利加优点系数（BFOM）约为 0.2 GW/cm2。在正向压降为 3 V 时，正向电流密度为 465 A/cm2。在 800 V 电压下，模拟反向漏电流密度保持在 9.0 mA/cm2 的低水平。浮动磁场环与结点端接扩展（JTE）一起用作边缘端接方法，以获得较高的击穿电压。研究了 β-Ga2O3 周期性鳍片宽度波动对 JBS 电特性的影响。由于 p 型 GaN 增强了侧壁耗尽效应，当 β-Ga2O3 周期性鳍片宽度减小时，正向电流（IF）和反向电流（IR）都会减小。这项研究的结果表明，p-GaN/n-Ga2O3 JBS 二极管在功率器件应用中大有可为。
{"title":"Design and Evaluation of β-Ga2O3 junction barrier Schottky diode with p-GaN Heterojunction","authors":"Phuc Hong Than, Tho Than, Yasushi Takaki","doi":"10.1088/1402-4896/ad6da2","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da2","url":null,"abstract":"\u0000 A novel design for a junction barrier Schottky (JBS) diode based on a p-GaN/n-Ga2O3 heterojunction is proposed, exhibiting superior static characteristics and a higher breakdown capability compared to the traditional Ga2O3 Schottky barrier diode (SBD). By utilizing wide-bandgap p-type GaN, the β-Ga2O3 JBS diodes demonstrate a turn-on voltage (Von) of approximately 0.8 V. Moreover, a breakdown voltage (Vbr) of 880 V and a specific on-resistance (Ron,sp) of 3.96 mΩ·cm2 are achieved, resulting in a Baliga’s figure of merit (BFOM) of approximately 0.2 GW/cm2. A forward current density of 465 A/cm2 at a forward voltage drop of 3 V is attained. The simulated reverse leakage current density remains low at 9.0 mA/cm2 at 800 V. Floating field rings, in conjunction with junction termination extension (JTE), were utilized as edge termination methods to attain a high breakdown voltage. The impact of β-Ga2O3 periodic fin width fluctuations on the electrical characteristics of JBS was investigated. Due to the enhanced sidewall depletion effect caused by p-type GaN, the forward current (IF) and reverse current (IR) decrease when the β-Ga2O3 periodic fin width decreases. The findings of this study indicate the remarkable promise of p-GaN/n-Ga2O3 JBS diodes for power device applications.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"4 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141921586","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}
Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad6da3
Mehboob Ul Haq, Sirajul Haq
This work addresses an efficient and new numerical technique utilizing non-polynomial splines to solve system of reaction diffusion equations (RDS). These system of equations arise in pattern formation of some special biological and chemical reactions. Different types of RDS are in the form of spirals, hexagons, stripes, and dissipative solitons. Chemical concentrations can travel as waves in reaction-diffusion systems, where wave like behaviour can be seen. The purpose of this research is to develop a stable, highly accurate and convergent scheme for the solution of aforementioned model. The method proposed in this paper utilizes forward difference for time discretization whereas for spatial discretization cubic non-polynomial spline is used to get approximate solution of the system under consideration. Furthermore, stability of the scheme is discussed via Von-Neumann criteria. Different orders of convergence is achieved for the scheme during a theoretical convergence test. Suggested method is tested for performance on various well known models such as, Brusselator, Schnakenberg, isothermal as well as linear models. Accuracy and efficiency of the scheme is checked in terms of relative error (ER) and L∞ norms for different time and space step sizes. The newly obtained results are analyzed and compared with those available in literature.
{"title":"Non-Polynomial Spline Method for Computational study of ReactionDiffusion System","authors":"Mehboob Ul Haq, Sirajul Haq","doi":"10.1088/1402-4896/ad6da3","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da3","url":null,"abstract":"\u0000 This work addresses an efficient and new numerical technique utilizing non-polynomial splines to solve system of reaction diffusion equations (RDS). These system of equations arise in pattern formation of some special biological and chemical reactions. Different types of RDS are in the form of spirals, hexagons, stripes, and dissipative solitons. Chemical concentrations can travel as waves in reaction-diffusion systems, where wave like behaviour can be seen. The purpose of this research is to develop a stable, highly accurate and convergent scheme for the solution of aforementioned model. The method proposed in this paper utilizes forward difference for time discretization whereas for spatial discretization cubic non-polynomial spline is used to get approximate solution of the system under consideration. Furthermore, stability of the scheme is discussed via Von-Neumann criteria. Different orders of convergence is achieved for the scheme during a theoretical convergence test. Suggested method is tested for performance on various well known models such as, Brusselator, Schnakenberg, isothermal as well as linear models. Accuracy and efficiency of the scheme is checked in terms of relative error (ER) and L∞ norms for different time and space step sizes. The newly obtained results are analyzed and compared with those available in literature.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"49 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922971","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}
Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad6dab
Ş. Çavdar, Pınar Oruç, S. Eymur, Tugluoglu Nihat
In this study, a Schottky barrier diode with an Al/TPA-IFA/p-Si structure was fabricated using spin coating and thermal evaporation methods. Using forward and reverse bias I–V measurement, we examined the key electrical characteristics of the Al/TPA-IFA/p-Si diode, including Φ_b, n, R_s, and N_ss; we also estimated V_D, N_A, E_F, 〖∆Φ〗_b, W_D, Φ_b and N_ss using C–V measurements under the different frequencies (10, 50, 100, 500 kHz, and 1 MHz) at room temperature. Using I–V data and the Thermionic Emission (TE) theory, basic electrical parameters such as ideality factor (n), and barrier height (Φ_b) values were computed as 3.01 and 0.716 eV. The fundamental diode parameters are highly frequency-dependent. It was also found that the series Resistance (R_s) values reduced with increasing frequency, but the barrier height (Φ_b) and the width of the depletion layer (W_D) increased. It was found that when frequency increased, the diode capacitance reduced for our new Schottky-type diode. The diode's potential conduction mechanisms were examined through the utilization of reverse "ln" I-V^0.5 and forward "ln" I-V graphs. The transport properties of Al/TPA-IFA/p-Si diode are primarily governed by ohmic conduction, Space Charge Limited Current (SCLC), and Trap Charge Limited Current (TCLC) mechanisms at low, moderate, and high voltages, respectively. It was concluded that the Poole-Frenkel Emission (PFE) mechanism was dominant for the Al/TPA-IFA/p-Si diode. Ultimately, the findings confirmed that the TPA-IFA-based diode could be obtained for the electronic application.
{"title":"Frequency-dependent capacitance and conductance characteristics and current transport mechanisms of Schottky diodes with TPA-IFA organic interfacial layer","authors":"Ş. Çavdar, Pınar Oruç, S. Eymur, Tugluoglu Nihat","doi":"10.1088/1402-4896/ad6dab","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6dab","url":null,"abstract":"\u0000 In this study, a Schottky barrier diode with an Al/TPA-IFA/p-Si structure was fabricated using spin coating and thermal evaporation methods. Using forward and reverse bias I–V measurement, we examined the key electrical characteristics of the Al/TPA-IFA/p-Si diode, including Φ_b, n, R_s, and N_ss; we also estimated V_D, N_A, E_F, 〖∆Φ〗_b, W_D, Φ_b and N_ss using C–V measurements under the different frequencies (10, 50, 100, 500 kHz, and 1 MHz) at room temperature. Using I–V data and the Thermionic Emission (TE) theory, basic electrical parameters such as ideality factor (n), and barrier height (Φ_b) values were computed as 3.01 and 0.716 eV. The fundamental diode parameters are highly frequency-dependent. It was also found that the series Resistance (R_s) values reduced with increasing frequency, but the barrier height (Φ_b) and the width of the depletion layer (W_D) increased. It was found that when frequency increased, the diode capacitance reduced for our new Schottky-type diode. The diode's potential conduction mechanisms were examined through the utilization of reverse \"ln\" I-V^0.5 and forward \"ln\" I-V graphs. The transport properties of Al/TPA-IFA/p-Si diode are primarily governed by ohmic conduction, Space Charge Limited Current (SCLC), and Trap Charge Limited Current (TCLC) mechanisms at low, moderate, and high voltages, respectively. It was concluded that the Poole-Frenkel Emission (PFE) mechanism was dominant for the Al/TPA-IFA/p-Si diode. Ultimately, the findings confirmed that the TPA-IFA-based diode could be obtained for the electronic application.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"48 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923698","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}
Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad6da9
Ronald Benjamin
We investigate a thermal ratchet based on a Brownian particle in a spatially periodic square-well potential driven by a time-dependent square-wave signal. In this model, we rock the Brownian particle between two square-well potentials tilted in opposite directions to induce a net current. Employing Stratonovich’s formula and an independent approach using suitable boundary conditions and a normalization condition, we obtain an exact expression for the current in the adiabatic limit, and we observe that there are optimal values of various parameters at which the current can be maximized. In several parameter regimes, our simple non-linear model displays a behavior distinct from some other models of a rocked ratchet. For example, a reversal in the current direction is observed as the square-wave signal's amplitude or the thermal bath's temperature is varied. However, under similar conditions, no such current reversal was seen in the case of a periodically rocked Brownian motor in a sawtooth or a smooth potential. Furthermore, unlike the latter type of rocked Brownian motors, the square-well model yields zero current in the deterministic limit, as thermal energy is indispensable for the functioning of the motor.
{"title":"Noise-induced transport in a periodic square-well potential","authors":"Ronald Benjamin","doi":"10.1088/1402-4896/ad6da9","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da9","url":null,"abstract":"\u0000 We investigate a thermal ratchet based on a Brownian particle in a spatially periodic square-well potential driven by a time-dependent square-wave signal. In this model, we rock the Brownian particle between two square-well potentials tilted in opposite directions to induce a net current. Employing Stratonovich’s formula and an independent approach using suitable boundary conditions and a normalization condition, we obtain an exact expression for the current in the adiabatic limit, and we observe that there are optimal values of various parameters at which the current can be maximized. In several parameter regimes, our simple non-linear model displays a behavior distinct from some other models of a rocked ratchet. For example, a reversal in the current direction is observed as the square-wave signal's amplitude or the thermal bath's temperature is varied. However, under similar conditions, no such current reversal was seen in the case of a periodically rocked Brownian motor in a sawtooth or a smooth potential. Furthermore, unlike the latter type of rocked Brownian motors, the square-well model yields zero current in the deterministic limit, as thermal energy is indispensable for the functioning of the motor.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"58 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923489","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}
Pub Date : 2024-08-09DOI: 10.1088/1402-4896/ad6da6
N. Kander, Bikash Gajar, Sajib Biswas, Shubhadip Moulick, A. K. Das
Bi-based binary alloys have drawn enormous attention in modern condensed matter research for their novel topological property. Here, we have explored the quantum-transport properties of a 100nm Bi2Se3 topological insulator thin film grown by an indigenously developed electron-beam-evaporator through co-deposition technique. A detailed study about the structural, elemental, and morphological analysis has been presented through the GI-XRD, Raman spectroscopy, XPS, EDX, SEM, and AFM characterization. Finally, we have investigated the angle and temperature-dependent magneto-conductance properties of our deposited films, which indicate the surface-electron dominated quantum-transport has occurred. Interestingly, our Bi2Se3 film exhibits 2D weak anti-localization and Subnikov-de Hass oscillation features. From which some novel topological parameters are explored, such as, Berry phase (β), phase-coherence-length (lϕ), Fermi velocity (vF), wave vector (kF), Dingle temperature (TD), quantum mobility (μq), and cyclotron mass (mc). The estimated β = 0.7π and mc = 0.17me, indicate that the topologically protected massless Dirac particles can be achieved in this kind of system.
{"title":"Obtained Berry phase and cyclotron mass of Bi2Se3 topological insulator thin film through weak anti-localization and Shubnikov-de Haas oscillation studies","authors":"N. Kander, Bikash Gajar, Sajib Biswas, Shubhadip Moulick, A. K. Das","doi":"10.1088/1402-4896/ad6da6","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da6","url":null,"abstract":"\u0000 Bi-based binary alloys have drawn enormous attention in modern condensed matter research for their novel topological property. Here, we have explored the quantum-transport properties of a 100nm Bi2Se3 topological insulator thin film grown by an indigenously developed electron-beam-evaporator through co-deposition technique. A detailed study about the structural, elemental, and morphological analysis has been presented through the GI-XRD, Raman spectroscopy, XPS, EDX, SEM, and AFM characterization. Finally, we have investigated the angle and temperature-dependent magneto-conductance properties of our deposited films, which indicate the surface-electron dominated quantum-transport has occurred. Interestingly, our Bi2Se3 film exhibits 2D weak anti-localization and Subnikov-de Hass oscillation features. From which some novel topological parameters are explored, such as, Berry phase (β), phase-coherence-length (lϕ), Fermi velocity (vF), wave vector (kF), Dingle temperature (TD), quantum mobility (μq), and cyclotron mass (mc). The estimated β = 0.7π and mc = 0.17me, indicate that the topologically protected massless Dirac particles can be achieved in this kind of system.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"54 29","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923983","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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