Pub Date : 2024-08-08DOI: 10.1088/1402-4896/ad69d8
Arighna Basak, Arpan Deyasi and Angsuman Sarkar
Impact of underlap layer is analytically investigated on asymmetric junctionless dual material double gate MOSFET (AJDMDG) to reduce subthreshold slope and threshold voltage, which are two essential requirements with shrinking device dimensions to avoid short channel effects. The model utilizes two-dimensional Poisson’s equation with parabolic approximation for determining electrical parameters where dimensional ranges are kept within fabrication limit. Excellent accuracy is found for the obtained analytical outcome, when compared with results obtained from TCAD ATLAS simulator. Comparative study is extended for conventional junctionless DMDG (JDMDG) and underlap asymmetric junctionless single material DGFET (UAJDG) device, having identical dimensional parameters and biasing ranges; where the present structure exhibits superior performance in terms of threshold voltage, subthreshold slope and DIBL of 34.57%, 62.85% and 69.85% respectively compared to JDMDG and 12.50%, 26.08% and 40.25% respectively w.r.t UAJDG structure. Supremacy of the proposed architecture is further established with RF/analog Figures of Merit (FOMs), which are essential for designing low power analog amplifier.
{"title":"Impact of underlap layer on DC and RF/analog performance of asymmetric junctionless dual material double gate MOSFET for low-power analog amplifier design","authors":"Arighna Basak, Arpan Deyasi and Angsuman Sarkar","doi":"10.1088/1402-4896/ad69d8","DOIUrl":"https://doi.org/10.1088/1402-4896/ad69d8","url":null,"abstract":"Impact of underlap layer is analytically investigated on asymmetric junctionless dual material double gate MOSFET (AJDMDG) to reduce subthreshold slope and threshold voltage, which are two essential requirements with shrinking device dimensions to avoid short channel effects. The model utilizes two-dimensional Poisson’s equation with parabolic approximation for determining electrical parameters where dimensional ranges are kept within fabrication limit. Excellent accuracy is found for the obtained analytical outcome, when compared with results obtained from TCAD ATLAS simulator. Comparative study is extended for conventional junctionless DMDG (JDMDG) and underlap asymmetric junctionless single material DGFET (UAJDG) device, having identical dimensional parameters and biasing ranges; where the present structure exhibits superior performance in terms of threshold voltage, subthreshold slope and DIBL of 34.57%, 62.85% and 69.85% respectively compared to JDMDG and 12.50%, 26.08% and 40.25% respectively w.r.t UAJDG structure. Supremacy of the proposed architecture is further established with RF/analog Figures of Merit (FOMs), which are essential for designing low power analog amplifier.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-08-08DOI: 10.1088/1402-4896/ad6944
Jayanta Bhattacharjee and S D Singh
The relevant parameters of electron–phonon (e-ph) interaction, like mean phonon temperature and e-ph interaction strength for Al-substituted β-Ga2O3, i.e., β-(AlxGa1–x)2O3 alloys, have been determined from the fitting of the temperature dependence of the band gap using Bose–Einstein empirical model. Both e-ph interaction strength and mean phonon temperature decrease sharply for initial Al compositions; then, they increase slightly and become more or less constant. This is explained by using the already existed concepts of propagon and diffuson for the phonon modes that interact with the electrons. Presence of two sublattices at the local level is found to be the origin of diffuson-like behaviour of phonon modes in β-(AlxGa1–x)2O3 alloyed system, which vibrate independently like a non-propagating oscillator and diffuse through the β-(AlxGa1–x)2O3 lattice. The diffuson-like behaviour of phonon modes in the β-(AlxGa1–x)2O3 alloy is found to be responsible for the reduction in e-ph interaction. The reduction of e-ph interaction strength of β-Ga2O3 with Al substitution may lead to the better performance of power devices working at higher temperatures.
{"title":"Effect of Al substitution on the electron-phonon interaction for β-Ga2O3","authors":"Jayanta Bhattacharjee and S D Singh","doi":"10.1088/1402-4896/ad6944","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6944","url":null,"abstract":"The relevant parameters of electron–phonon (e-ph) interaction, like mean phonon temperature and e-ph interaction strength for Al-substituted β-Ga2O3, i.e., β-(AlxGa1–x)2O3 alloys, have been determined from the fitting of the temperature dependence of the band gap using Bose–Einstein empirical model. Both e-ph interaction strength and mean phonon temperature decrease sharply for initial Al compositions; then, they increase slightly and become more or less constant. This is explained by using the already existed concepts of propagon and diffuson for the phonon modes that interact with the electrons. Presence of two sublattices at the local level is found to be the origin of diffuson-like behaviour of phonon modes in β-(AlxGa1–x)2O3 alloyed system, which vibrate independently like a non-propagating oscillator and diffuse through the β-(AlxGa1–x)2O3 lattice. The diffuson-like behaviour of phonon modes in the β-(AlxGa1–x)2O3 alloy is found to be responsible for the reduction in e-ph interaction. The reduction of e-ph interaction strength of β-Ga2O3 with Al substitution may lead to the better performance of power devices working at higher temperatures.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-08-08DOI: 10.1088/1402-4896/ad6492
F Riegger, F Andersson and J Robertsson
The space-based Laser Interferometry Space Antenna (LISA) is a gravitational waves observatory currently under development. It comprises three spacecraft, each traveling in a heliocentric orbit that is weakly eccentric and inclined. Gravitational waves comprise two polarization components. They will be detected by conducting interferometric Doppler measurements between the LISA spacecraft. Among other factors, the signal strength of the Doppler measurements will depend on the location of the GW source, the GW polarization angle, and the orbits of the spacecraft. Thus, the signal strength of the Doppler measurements will vary over time. For given spacecraft orbits, we derive bounds on the signal strength that are functions of the source location. These bounds are simple, explicit expressions, and we refer to them as the directional pre-sensitivity. Using the directional pre-sensitivity, we construct a metric for the relative change in the signal strength depending on the source location and the spacecraft orbits. We illustrate how this formalism can be used to assess the signal strength for several examples of chosen orbits.
天基激光干涉测量空间天线（LISA）是目前正在开发的引力波观测站。它由三个航天器组成，每个航天器都在一个弱偏心和倾斜的日心轨道上运行。引力波包括两种极化成分。将通过在 LISA 航天器之间进行干涉多普勒测量来探测引力波。除其他因素外，多普勒测量的信号强度将取决于引力波源的位置、引力波偏振角和航天器的轨道。因此，多普勒测量的信号强度将随时间而变化。对于给定的航天器轨道，我们推导出信号强度的边界，这些边界是信号源位置的函数。这些界限是简单明了的表达式，我们将其称为方向预灵敏度。利用方向预敏感度，我们构建了一个信号强度相对变化的度量，它取决于信号源位置和航天器轨道。我们将举例说明如何利用这一形式来评估几个所选轨道的信号强度。
{"title":"Directional pre-sensitivity of the laser interferometer space antenna","authors":"F Riegger, F Andersson and J Robertsson","doi":"10.1088/1402-4896/ad6492","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6492","url":null,"abstract":"The space-based Laser Interferometry Space Antenna (LISA) is a gravitational waves observatory currently under development. It comprises three spacecraft, each traveling in a heliocentric orbit that is weakly eccentric and inclined. Gravitational waves comprise two polarization components. They will be detected by conducting interferometric Doppler measurements between the LISA spacecraft. Among other factors, the signal strength of the Doppler measurements will depend on the location of the GW source, the GW polarization angle, and the orbits of the spacecraft. Thus, the signal strength of the Doppler measurements will vary over time. For given spacecraft orbits, we derive bounds on the signal strength that are functions of the source location. These bounds are simple, explicit expressions, and we refer to them as the directional pre-sensitivity. Using the directional pre-sensitivity, we construct a metric for the relative change in the signal strength depending on the source location and the spacecraft orbits. We illustrate how this formalism can be used to assess the signal strength for several examples of chosen orbits.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-08-07DOI: 10.1088/1402-4896/ad69e0
Qianqian Jia, Run-hua Shi and Huijie Li
Cloud computing, as a popular technology in recent years, has greatly facilitated the development of data outsourcing services. However, when users access sensitive data stored in the cloud, ensuring the security of data remains a pressing challenge. In this paper, we present a privacy-preserving keyword query scheme for outsourced data in cloud environment. Furthermore, to implement this scheme, we propose a series of quantum basic protocols with single qubits. The proposed basic protocols do not require the execution of quantum gate operations, and the necessary measurements are only Bell measurements based on measurement-device-independence. Therefore, it is practical and feasible under current technology. Moreover, compared with classical schemes, our scheme has higher security (i.e., quantum security). Finally, we conduct simulation experiments in IBM Qiskit to verify the correctness and feasibility of the critical parts of the scheme.
云计算作为近年来的热门技术，极大地促进了数据外包服务的发展。然而，当用户访问存储在云中的敏感数据时，如何确保数据的安全性仍然是一个亟待解决的难题。本文针对云环境中的外包数据提出了一种保护隐私的关键字查询方案。此外，为了实现这一方案，我们提出了一系列使用单量子比特的量子基本协议。所提出的基本协议不需要执行量子门操作，必要的测量也只是基于测量设备无关性的贝尔测量。因此，在现有技术条件下，它是切实可行的。此外，与经典方案相比，我们的方案具有更高的安全性（即量子安全性）。最后，我们在 IBM Qiskit 中进行了仿真实验，验证了方案关键部分的正确性和可行性。
{"title":"Privacy-preserving keyword query quantum scheme for outsourced data in cloud environments","authors":"Qianqian Jia, Run-hua Shi and Huijie Li","doi":"10.1088/1402-4896/ad69e0","DOIUrl":"https://doi.org/10.1088/1402-4896/ad69e0","url":null,"abstract":"Cloud computing, as a popular technology in recent years, has greatly facilitated the development of data outsourcing services. However, when users access sensitive data stored in the cloud, ensuring the security of data remains a pressing challenge. In this paper, we present a privacy-preserving keyword query scheme for outsourced data in cloud environment. Furthermore, to implement this scheme, we propose a series of quantum basic protocols with single qubits. The proposed basic protocols do not require the execution of quantum gate operations, and the necessary measurements are only Bell measurements based on measurement-device-independence. Therefore, it is practical and feasible under current technology. Moreover, compared with classical schemes, our scheme has higher security (i.e., quantum security). Finally, we conduct simulation experiments in IBM Qiskit to verify the correctness and feasibility of the critical parts of the scheme.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-08-07DOI: 10.1088/1402-4896/ad6946
Oktay Karaduman, İskender Özkul and Canan Aksu Canbay
Cu-based shape memory alloys (SMAs), except for exhibiting shape recovery, superelasticity, and high damping, are desirable because these smart materials have higher electrical and thermal conductivity and much lower prices than NiTi SMAs. However, they also have some downsides in mechanical strength and brittleness (mostly stemming from their coarse grain structure) and thermal instability. Therefore, adding some grain refining elements to these SMAs to improve their shape memory effect (SME), and thermal, structural, and mechanical properties is a widespread and simple way that significantly affects their martensitic phase transitions, structure, and mechanical properties. One of these grain-refining elements is titanium. Its thermal conductivity is lower than those of Cu and Al elements and has a low solubility in Cu-matrix. Besides the effects of small Al variations, the use of minor amounts of titanium in binary CuAl-base alloys can show impressive effects on all characteristics of these shape memory alloys, such as shape memory effect properties, martensitic transformation kinetics parameters, and microstructural features. In this research work, CuAlTi ternary high-temperature shape memory alloys (HTSMAs) with new compositions were produced by the arc melting method without a complicating use of Mn or Ni components in usual ternary CuAlMn and CuAlNi shape memory alloys. Thermal analyses of the prepared samples of the alloys were investigated by using differential scanning calorimetry (DSC) and differential thermal analysis (DTA) measurements. In contrast, x-ray diffraction (XRD) test results and optical micrographs were used for analyzing the structure of the alloy samples. The effect of different amounts of low soluble and grain refining Ti element on the binary CuAl alloy system was investigated.
铜基形状记忆合金（SMA）除了具有形状恢复、超弹性和高阻尼之外，还具有更高的导电性和导热性，而且价格比镍钛 SMA 低得多。不过，它们也有一些缺点，如机械强度和脆性（主要源于其粗晶粒结构）以及热不稳定性。因此，在这些 SMA 中添加一些晶粒细化元素以改善其形状记忆效应（SME）以及热、结构和机械性能，是一种广泛而简单的方法，可显著影响其马氏体相变、结构和机械性能。钛就是这些晶粒细化元素之一。钛的热导率低于铜和铝元素，在铜基体中的溶解度也较低。除了少量铝元素变化的影响外，在二元 CuAl 基合金中使用少量钛元素也会对这些形状记忆合金的所有特性，如形状记忆效应性能、马氏体转变动力学参数和微观结构特征产生令人印象深刻的影响。在这项研究工作中，采用电弧熔炼法制备了具有新成分的 CuAlTi 三元高温形状记忆合金（HTSMA），而没有使用通常的 CuAlMn 和 CuAlNi 三元形状记忆合金中复杂的 Mn 或 Ni 成分。利用差示扫描量热法（DSC）和差示热分析法（DTA）对制备的合金样品进行了热分析。而 X 射线衍射（XRD）测试结果和光学显微照片则用于分析合金样品的结构。研究了不同数量的低溶解性和晶粒细化 Ti 元素对二元 CuAl 合金体系的影响。
{"title":"Hysteresis gap-shrinking and structural effects of minor Al and Ti modifications on binary CuAl-based high-temperature shape memory alloys","authors":"Oktay Karaduman, İskender Özkul and Canan Aksu Canbay","doi":"10.1088/1402-4896/ad6946","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6946","url":null,"abstract":"Cu-based shape memory alloys (SMAs), except for exhibiting shape recovery, superelasticity, and high damping, are desirable because these smart materials have higher electrical and thermal conductivity and much lower prices than NiTi SMAs. However, they also have some downsides in mechanical strength and brittleness (mostly stemming from their coarse grain structure) and thermal instability. Therefore, adding some grain refining elements to these SMAs to improve their shape memory effect (SME), and thermal, structural, and mechanical properties is a widespread and simple way that significantly affects their martensitic phase transitions, structure, and mechanical properties. One of these grain-refining elements is titanium. Its thermal conductivity is lower than those of Cu and Al elements and has a low solubility in Cu-matrix. Besides the effects of small Al variations, the use of minor amounts of titanium in binary CuAl-base alloys can show impressive effects on all characteristics of these shape memory alloys, such as shape memory effect properties, martensitic transformation kinetics parameters, and microstructural features. In this research work, CuAlTi ternary high-temperature shape memory alloys (HTSMAs) with new compositions were produced by the arc melting method without a complicating use of Mn or Ni components in usual ternary CuAlMn and CuAlNi shape memory alloys. Thermal analyses of the prepared samples of the alloys were investigated by using differential scanning calorimetry (DSC) and differential thermal analysis (DTA) measurements. In contrast, x-ray diffraction (XRD) test results and optical micrographs were used for analyzing the structure of the alloy samples. The effect of different amounts of low soluble and grain refining Ti element on the binary CuAl alloy system was investigated.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-08-07DOI: 10.1088/1402-4896/ad6945
Shankar S Humbe, Pratibha S Jadhav, Girish M Joshi and R R Deshmukh
In the present study we emphasized on the dielectric properties of Ethylene Vinyl Acetate (EVA) filled with untreated and plasma-treated graphene oxide (GO). The chemical fingerprints of EVA/GO were analysed using FTIR. Decreased ID/IG ratio from 2.99 to 2.75 and 1.60 to 1.16 due to exposed plasma was confirmed by Raman spectroscopy. X-ray diffraction (XRD) disclosed the decreased degree of crystallinity. Electric properties were measured by impedance analyser, dielectric constant was increased upto 11% for untreated GO dispersion and 47% for Air treated Plasma GO dispersed EVA composites. Plasma treatment further improved the exfoliated sites of GO and induced the defects, leading to optimized dielectric properties. Improved dielectric properties of EVA/GO can provide valuable insights into the potential applications in the field of electrical connectors, film capacitors, and pseudo capacitors.
在本研究中，我们重点研究了填充了未经处理和等离子处理的氧化石墨烯（GO）的乙烯-醋酸乙烯酯（EVA）的介电性能。我们使用傅立叶变换红外光谱分析了 EVA/GO 的化学指纹。拉曼光谱证实，由于暴露在等离子体中，ID/IG 比率从 2.99 降至 2.75，从 1.60 降至 1.16。X 射线衍射 (XRD) 揭示了结晶度的降低。通过阻抗分析仪测量了电性能，未经处理的 GO 分散体的介电常数增加了 11%，而经过空气处理的等离子体 GO 分散 EVA 复合材料的介电常数增加了 47%。等离子处理进一步改善了 GO 的剥离点，并诱发了缺陷，从而优化了介电性能。EVA/GO 介电性能的改善可为电连接器、薄膜电容器和伪电容器领域的潜在应用提供有价值的见解。
{"title":"Study of dielectric properties of polymer/air plasma treated graphene oxide nanocomposites for electronic applications","authors":"Shankar S Humbe, Pratibha S Jadhav, Girish M Joshi and R R Deshmukh","doi":"10.1088/1402-4896/ad6945","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6945","url":null,"abstract":"In the present study we emphasized on the dielectric properties of Ethylene Vinyl Acetate (EVA) filled with untreated and plasma-treated graphene oxide (GO). The chemical fingerprints of EVA/GO were analysed using FTIR. Decreased ID/IG ratio from 2.99 to 2.75 and 1.60 to 1.16 due to exposed plasma was confirmed by Raman spectroscopy. X-ray diffraction (XRD) disclosed the decreased degree of crystallinity. Electric properties were measured by impedance analyser, dielectric constant was increased upto 11% for untreated GO dispersion and 47% for Air treated Plasma GO dispersed EVA composites. Plasma treatment further improved the exfoliated sites of GO and induced the defects, leading to optimized dielectric properties. Improved dielectric properties of EVA/GO can provide valuable insights into the potential applications in the field of electrical connectors, film capacitors, and pseudo capacitors.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-08-07DOI: 10.1088/1402-4896/ad69e9
F Chogle and O Olendski
The influence of electric field on a straight Dirichlet waveguide with Neumann window(s) of arbitrary length L is studied theoretically for 2D and 3D geometries. The energy spectrum for the corresponding bound states was obtained and their dependence on was analysed. At low , the boundary of the window(s) influenced the properties of the particle contrary to the high case, where the energies and localization of particle were seen similar in all the geometries. The critical lengths Lcr, at which higher excited state emerges into the continuum, at different were found and their behavior was explained qualitatively. It was found that at high , the critical lengths of Dirichlet-Neumann boundary window approach the Neumann-Neumann boundary window. This is due to the increase in the fundamental propagation threshold of transverse modes in the wall and window region. On the other hand, the Neumann-Dirichlet boundary window showed an opposite behavior. Furthermore, the polarization of ground state was obtained for different geometries. It was proved that at small L, the polarization reduces to its 1D case. A mathematical treatment and semi classical explanation was provided. Comparative analysis of the 2D and 3D geometries reveals their qualitative similarity and quantitative differences.
理论研究了电场对带有任意长度 L 的诺伊曼窗口的直狄利克特波导的影响。获得了相应束缚态的能谱，并分析了它们对电场的依赖性。在低频情况下，窗口边界对粒子特性的影响与高频情况相反，在高频情况下，粒子的能量和定位在所有几何形状中都是相似的。我们发现了不同的临界长度 Lcr，在这些临界长度上，高激发态会出现在连续体中，并定性地解释了它们的行为。研究发现，在高Ⅴ阶段，迪里赫特-诺伊曼边界窗口的临界长度接近诺伊曼-诺伊曼边界窗口。这是由于横向模态在壁和窗区域的基本传播阈值增大所致。另一方面，Neumann-Dirichlet 边界窗口则表现出相反的行为。此外，还得到了不同几何形状下基态的极化情况。结果证明，在 L 较小的情况下，极化会还原为一维情况。研究提供了数学处理和半经典解释。对二维和三维几何形状的比较分析表明了它们在质量上的相似性和数量上的差异。
{"title":"Bound-state evolution of Dirichlet waveguide with Neumann window(s) in transverse electric fields","authors":"F Chogle and O Olendski","doi":"10.1088/1402-4896/ad69e9","DOIUrl":"https://doi.org/10.1088/1402-4896/ad69e9","url":null,"abstract":"The influence of electric field on a straight Dirichlet waveguide with Neumann window(s) of arbitrary length L is studied theoretically for 2D and 3D geometries. The energy spectrum for the corresponding bound states was obtained and their dependence on was analysed. At low , the boundary of the window(s) influenced the properties of the particle contrary to the high case, where the energies and localization of particle were seen similar in all the geometries. The critical lengths Lcr, at which higher excited state emerges into the continuum, at different were found and their behavior was explained qualitatively. It was found that at high , the critical lengths of Dirichlet-Neumann boundary window approach the Neumann-Neumann boundary window. This is due to the increase in the fundamental propagation threshold of transverse modes in the wall and window region. On the other hand, the Neumann-Dirichlet boundary window showed an opposite behavior. Furthermore, the polarization of ground state was obtained for different geometries. It was proved that at small L, the polarization reduces to its 1D case. A mathematical treatment and semi classical explanation was provided. Comparative analysis of the 2D and 3D geometries reveals their qualitative similarity and quantitative differences.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-08-07DOI: 10.1088/1402-4896/ad695c
Praveen Palabindela, Jaivardhan Sinha and Bhaskar Chandra Behera
Ferromagnetic rings, particularly asymmetric Permalloy (Py) rings are recognized as promising configurations for spintronic devices, offering additional degrees of freedom for manipulating magnetic states, especially in vortex configurations. Through micromagnetic simulations, our study explores the impact on magnetization states and spin configuration concerning ring symmetry, aligning with the interest in controlling vortex states for information storage. We initially obtained zero-field spin configurations by varying ring thickness (t), observing a 360° domain wall in rings with t < 12 nm and bi-vortex wall in rings with t ∼36 nm during magnetization reversal. Notably, an extended stability of the global-vortex state was observed in rings with t > 36 nm, indicating the dominance of global-vortex nucleation in thick asymmetric rings during domain wall movement. We investigate the hysteresis loops and spin configurations by varying the in-plane and out-of-plane anisotropy values. Our findings reveal the presence of multiple vortex cores with different polarities and sense of rotations in the ring for the in-plane anisotropy ∼30 to ∼40 kJ m−3. Additionally, a global-vortex with two vortex cores was formed due to demagnetization energy. We analysed the energy profile of stable magnetization states for various t and anisotropy values. Interestingly, the shape of the hysteresis loop changes significantly for the disc containing different shapes of void. Circular and square-shaped geometries suggest that the bi-vortex state is a stable configuration during magnetization reversal in both cases. The study also indicates the stability of the vortex with a square-shaped void geometry up to a sufficiently large field. For the case of triangular-shaped voids, the global-vortex state was favored with even the small fields. The estimated spin canting angles are found to be correlated with the presence of vortex spin configurations. Overall, these results are important for the development of magnetization vortex-based spintronics devices.
铁磁环，尤其是非对称坡莫合金（Py）环，被认为是自旋电子器件的理想配置，为操纵磁态，尤其是涡旋配置提供了额外的自由度。通过微磁模拟，我们的研究探讨了环对称性对磁化状态和自旋配置的影响，这与控制涡旋状态以存储信息的兴趣相一致。我们最初通过改变环的厚度（t）来获得零场自旋构型，观察到在磁化反转过程中，t < 12 nm 的环具有 360° 的畴壁，而 t ∼ 36 nm 的环具有双涡壁。值得注意的是，在 t > 36 nm 的环中观察到了全局涡旋状态的扩展稳定性，这表明在畴壁运动过程中，全局涡旋成核在厚的不对称环中占主导地位。我们通过改变面内和面外各向异性值来研究滞后环和自旋构型。我们的研究结果表明，在平面内各向异性值为 ∼30 至 ∼40 kJ m-3 时，环中存在多个具有不同极性和旋转感的涡核。此外，由于去磁能量的作用，还形成了具有两个涡核的全局涡。我们分析了不同 t 和各向异性值下稳定磁化状态的能量曲线。有趣的是，对于含有不同形状空隙的圆盘，磁滞环的形状会发生显著变化。圆形和方形几何形状表明，在这两种情况下，双涡态都是磁化反转过程中的稳定构型。研究还表明，在磁场足够大的情况下，方形空隙几何形状的涡旋是稳定的。对于三角形空洞，即使磁场很小，全局涡旋态也很有利。估计的自旋倾斜角与涡旋自旋配置的存在相关。总之，这些结果对于开发基于磁化涡旋的自旋电子器件非常重要。
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Pub Date : 2024-08-07DOI: 10.1088/1402-4896/ad693f
Shubham Mehta and Poonam Redhu
This paper presents an integral lattice hydrodynamic model to examine the impact of driver’s anticipation and driving prediction with density deviation of leading vehicle under passing behavior. Both linear and nonlinear investigations have been used to obtain the stability condition and ‘modified Korteweg–de Vries (mKdV)’ equation is derived to further classify the nonlinear behavior of vehicular flow in terms of density waves, respectively. The linear stability condition shows that the stable region can be increased by decreasing the coefficient of predicted density deviation. Additionally, the stable region expands with a positive value of driver anticipation but contracts with a negative value. In comparison of the Nagatani and Redhu models, it is observed that for fixed value of density deviation coefficient, the new model conveys greater stability zone. To verify the theoretical findings, ‘numerical simulation’ has been conducted to examine the evolution of traffic flow in the presence of a small disturbances. The analytical results have been discussed for different passing rate with fixed value of driver’s anticipation and different values of density deviation coefficient. Furthermore, it has been noted that the stable region decreases for all passing rates when driver become more aware of the average speed of any neighbouring vehicles. The obtained results in this paper show that the traffic behavior with the existing model is more realistic. Additionally, this model will help in boosting vehicle movement efficiency, reducing congestion and enhancing road safety effectively .
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Pub Date : 2024-08-07DOI: 10.1088/1402-4896/ad6942
Nurul Farah Adilla Zaidi, Nur Najahatul Huda Saris, Muhammad Yusof Mohd Noor, Sumiaty Ambran, Mohd Rashidi Salim and Mohd Haniff Ibrahim
Transformer oil plays a crucial role in insulation and cooling within high-voltage transformers, but it degrades over time. This research proposes a durable sensor capable of detecting the refractive index (RI) of transformer oil when it exceeds the RI of the sensor structure, known as high refractive index (HRI) sensing. The study utilizes a no-core optical fiber (NCF) to monitor the quality of transformer oil. In this setup, single mode fiber (SMF) is employed as both the input and output of the NCF, forming an SMF-NCF-SMF (SNS) sensor. To date, to the use of an NCF in the SMF-NCF-SMF scheme has not been reported for high RI fiber sensing and transformer oil degradation detection. Additionally, this study provides an analysis of the influence of different diameters and lengths of NCF on the sensor’s sensitivity. The HRI sensing performance of the sensor was evaluated both numerically and experimentally by observing power spectrum changes due to leaky modes interference in response to varying transformer oil RI values from 1.4600 RIU to 1.5500 RIU. The NCF, with a geometry of 1 cm in length and 100 μm in diameter, demonstrated remarkable sensitivity, achieving up to 88.285 dBm/RIU for HRI values within the specified range. The sensor effectively discerned various aging levels of transformer oil in power transformer applications. Additionally, since the NCF structure is entirely composed of silica-based materials, it exhibited significant temperature resistance. These characteristics make the SNS structure well-suited for reliable deployment in challenging thermal environments.
变压器油在高压变压器的绝缘和冷却方面起着至关重要的作用，但它会随着时间的推移而退化。本研究提出了一种耐用的传感器，当变压器油的折射率（RI）超过传感器结构的折射率（RI）时，它就能检测到，这就是所谓的高折射率（HRI）传感。这项研究利用无芯光纤（NCF）来监测变压器油的质量。在该装置中，单模光纤（SMF）被用作 NCF 的输入和输出，形成了 SMF-NCF-SMF (SNS) 传感器。迄今为止，还没有关于在 SMF-NCF-SMF 方案中使用 NCF 进行高 RI 光纤传感和变压器油降解检测的报道。此外，本研究还分析了不同直径和长度的 NCF 对传感器灵敏度的影响。传感器的 HRI 传感性能通过数值和实验进行了评估，在变压器油 RI 值从 1.4600 RIU 到 1.5500 RIU 不等的情况下，观察泄漏模式干扰引起的功率谱变化。长度为 1 厘米、直径为 100 μm 的 NCF 显示出卓越的灵敏度，在指定范围内的 HRI 值最高可达 88.285 dBm/RIU。该传感器能有效辨别电力变压器应用中变压器油的各种老化程度。此外，由于 NCF 结构完全由硅基材料组成，因此具有显著的耐温性。这些特性使 SNS 结构非常适合在具有挑战性的热环境中可靠部署。
{"title":"Investigation of transformer oil aging using no-core optical fiber (NCF) sensor","authors":"Nurul Farah Adilla Zaidi, Nur Najahatul Huda Saris, Muhammad Yusof Mohd Noor, Sumiaty Ambran, Mohd Rashidi Salim and Mohd Haniff Ibrahim","doi":"10.1088/1402-4896/ad6942","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6942","url":null,"abstract":"Transformer oil plays a crucial role in insulation and cooling within high-voltage transformers, but it degrades over time. This research proposes a durable sensor capable of detecting the refractive index (RI) of transformer oil when it exceeds the RI of the sensor structure, known as high refractive index (HRI) sensing. The study utilizes a no-core optical fiber (NCF) to monitor the quality of transformer oil. In this setup, single mode fiber (SMF) is employed as both the input and output of the NCF, forming an SMF-NCF-SMF (SNS) sensor. To date, to the use of an NCF in the SMF-NCF-SMF scheme has not been reported for high RI fiber sensing and transformer oil degradation detection. Additionally, this study provides an analysis of the influence of different diameters and lengths of NCF on the sensor’s sensitivity. The HRI sensing performance of the sensor was evaluated both numerically and experimentally by observing power spectrum changes due to leaky modes interference in response to varying transformer oil RI values from 1.4600 RIU to 1.5500 RIU. The NCF, with a geometry of 1 cm in length and 100 μm in diameter, demonstrated remarkable sensitivity, achieving up to 88.285 dBm/RIU for HRI values within the specified range. The sensor effectively discerned various aging levels of transformer oil in power transformer applications. Additionally, since the NCF structure is entirely composed of silica-based materials, it exhibited significant temperature resistance. These characteristics make the SNS structure well-suited for reliable deployment in challenging thermal environments.","PeriodicalId":20067,"journal":{"name":"Physica Scripta","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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