Results in Physics最新文献

{"title":"Enhanced thermoelectric properties of bismuth telluride via Ultra-Low thermal conductivity BOSC compound addition","authors":"Nattharika Theekhasuk ,&nbsp;Nuttakrit Somdock ,&nbsp;Athorn Voraud ,&nbsp;Pichet Limsuwan ,&nbsp;Rachsak Sakdanuphab ,&nbsp;Aparporn Sakulkalavek","doi":"10.1016/j.rinp.2024.108056","DOIUrl":"10.1016/j.rinp.2024.108056","url":null,"abstract":"<div><div>This study aimed to enhance the thermoelectric properties of bismuth telluride by adding Bi₄O₄SeCl₂ (BOSC). Commercial N-type bismuth telluride was mixed with BOSC powder in varying concentrations. As the BOSC content increased, the carrier concentration also rose due to chlorine atoms acting as donor impurities. Despite this increase, the power factor values of the samples with BOSC additives did not significantly differ from those of the bare bismuth telluride sample. However, the total thermal conductivity decreased significantly with the addition of BOSC, reaching a minimum value of 0.54 W·m^–1·K^–1 at 150 °C for the sample with 1 wt% BOSC. Notably, the ZT value for the sample with 1 wt% BOSC was about 0.86, which is four times higher than that of the bare bismuth telluride sample. Our findings demonstrate superior thermoelectric performance, indicating a more efficient modification of thermoelectric properties through the addition of BOSC to the bismuth telluride matrix<strong>.</strong></div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108056"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi focus acoustic field generation using Dammann gratings for phased array transducers","authors":"Tatsuki Fushimi ,&nbsp;Yusuke Koroyasu","doi":"10.1016/j.rinp.2024.108040","DOIUrl":"10.1016/j.rinp.2024.108040","url":null,"abstract":"<div><div>Phased array transducers can shape acoustic fields for versatile manipulation; however, generating multiple focal points typically involves complex optimization. This study demonstrates that Dammann gratings – binary phase gratings originally used in optics to generate equal-intensity spot arrays – can be adapted for acoustics to create multiple equal-strength focal points with a phased array transducer. The transducer elements were assigned phases of 0 or <span><math><mi>π</mi></math></span>, based on a Dammann grating defined by its transition points. Simulations show that simple gratings with two transition points can generate fields with up to 12 focal points of nearly equal acoustic pressures. Compared to conventional multi-focus phase optimization techniques, the Dammann grating approach offers computational efficiency and facile reconfiguration of the focal pattern by adjusting the grating hologram. We tested this approach in numerical simulations with a hypothetical high-resolution array, achieving up to 12 focal points, and validated the efficacy of the Dammann grating in a conventional 16x16 transducer array through both simulations and experiments. This comparison highlights that while Dammann gratings effectively generate multi-focus fields, the recreation ability of these gratings in a conventional array shows a lower resolution than the hypothetical array. This study underlines the potential of adapting binary phase functions from photonics to enhance ultrasound-based acoustic manipulation for tasks requiring parallel actuation at multiple points.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108040"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring structural and electronic properties of topological insulator/graphene nano-heterostructures","authors":"Valentina Gallardo ,&nbsp;Bárbara Arce ,&nbsp;Francisco Muñoz ,&nbsp;Rodolfo San Martín ,&nbsp;Irina Zubritskaya ,&nbsp;Paula Giraldo-Gallo ,&nbsp;Caleb Z. Zerger ,&nbsp;Hari C. Manoharan ,&nbsp;Carolina Parra","doi":"10.1016/j.rinp.2024.108058","DOIUrl":"10.1016/j.rinp.2024.108058","url":null,"abstract":"<div><div>There is great interest in the study of topological insulator-based heterostructures due to expected emerging phenomena. However, a challenge of topological insulator (TI) research is the contribution of bulk conduction to the TI surface states. Both strain engineering and thickness control routes, which have been proposed to compensate for bulk doping, can be accessed through the use of nano-heterostructures consisting of topological insulator nanostructures grown on 2D materials. In this work, we report the synthesis of TI/graphene nano-heterostructures based on Bi₂Te₃ and Sb₂Te₃ nanoplatelets (NPs) grown on single-layer graphene. Various techniques were used to characterize this system in terms of morphology, thickness, composition, and crystal quality. We found that most of the obtained NPs are mainly &lt;30 nm thick with thickness-dependent crystal quality, observed by Raman measurements. Thinner NPs (1 or 2 quintuple layers) tend to replicate the topography of the underlying single-layer graphene, according to roughness analysis. Finally, we show preliminary studies of their band structure obtained by Low Temperature Scanning Tunneling Microscopy, Scanning Tunneling Spectroscopy, and by Density Functional Theory. We observe a highly negative E_D value which can be attributed to the presence of defects.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108058"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beyond two-octave coherent OAM supercontinuum generation in air-core Ge-doped ring fiber","authors":"Xiaoke Wu ,&nbsp;Pengfei Wang ,&nbsp;Yiwen Zhang ,&nbsp;Jian Yang ,&nbsp;Yuanpeng Liu ,&nbsp;Wenpu Geng ,&nbsp;Fei Yang ,&nbsp;Zhongqi Pan ,&nbsp;Yang Yue","doi":"10.1016/j.rinp.2024.108063","DOIUrl":"10.1016/j.rinp.2024.108063","url":null,"abstract":"<div><div>Orbital angular momentum (OAM) has emerged as a revolutionary technology for communication networks due to its ability to significantly increase the channel capacity. However, traditional optical fibers present significant hurdles to harnessing OAM’s full potential, including dispersion and limited bandwidth, which facilitates investigations on supercontinuum (SC) generation for OAM beams. In this paper, an air-core Ge-doped ring fiber is proposed and designed to support high-order OAM mode up to |<em>l</em>| = 24. To achieve this, the fiber has a high refractive index difference between the ring core and the cladding, enabling stable transmission of high-order OAM modes. A key feature of this design is the OAM₂₄_,₁ mode, which exhibits near-zero and flat dispersion. This characteristic translates into high coherence and a remarkably broad SC generation. The generated SC spans over two octaves (2336 nm) within the infrared wavelength range (764 nm to 3100 nm) at a power level of −40 dB. Furthermore, by optimizing the structural parameters, we ensure near-zero and flat dispersion characteristics for the other OAM modes (|<em>l</em>| &lt; 24), along with broad SC generation exceeding two octaves. This fiber design holds significant promise for future advancements in OAM beam transmission within the infrared spectrum.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108063"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A filtering polarization conversion electromagnetic surface for simultaneous RCS reduction and transmission","authors":"Huanhuan Yang,&nbsp;Tong Li,&nbsp;Jiawei Liao,&nbsp;Jing Zou,&nbsp;Tianhao Wu,&nbsp;Zexu Guo,&nbsp;Zhihao Li,&nbsp;Sijia Li","doi":"10.1016/j.rinp.2024.108064","DOIUrl":"10.1016/j.rinp.2024.108064","url":null,"abstract":"<div><div>A novel bifunctional single-sheet electromagnetic surface is proposed in this paper. To alleviate the mutual coupling of the two functions, an equivalent series circuit for linear-to-linear polarization conversion and an equivalent parallel circuit for filtering property are cascaded. Thanks to the combination of different equivalent circuits and the displacement of the resonating parts of two functions, the proposed electromagnetic surface demonstrates filtering and polarization conversion properties in adjacent frequency bands. When the unit cell is periodically arranged to constitute a finite metasurface, more than 6 dB RCS reduction is obtained from 7.7 GHz to 22.8 GHz. The physical mechanism reveals that the low RCS property of the metasurface is in virtue of both scattering field cancellation and transmission. The simple structure, relatively small cell size and good performance of the metasurface suggest it may be a promising candidate as antenna radome. Moreover, the proposed integration method of different functions in one surface makes the design of multifunctional electromagnetic surface easier and faster.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108064"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonreciprocal spin wave channeling in ferromagnetic/heavy-metal nanostrips","authors":"R.A. Gallardo ,&nbsp;P. Alvarado-Seguel ,&nbsp;F. Brevis ,&nbsp;C. Gonzalez-Fuentes ,&nbsp;J.W. González ,&nbsp;K. Lenz ,&nbsp;J. Lindner ,&nbsp;A. Roldán-Molina","doi":"10.1016/j.rinp.2024.108057","DOIUrl":"10.1016/j.rinp.2024.108057","url":null,"abstract":"<div><div>Nonreciprocity, unidirectionality, and channeling are essential concepts for potential magnonic applications. Nonreciprocity and unidirectionality ensure the efficient propagation of spin waves along predetermined paths with preferential directions, disrupting the symmetry of counterpropagating waves. Channeling fosters the development of intricate spin-wave networks, enabling more sophisticated functionalities. Integrating these concepts into practical applications will shape the future of spin-wave-based information processing devices. This article theoretically studies the dynamics of spin waves in a ferromagnetic strip coupled to a heavy-metal strip, where the nonreciprocity, unidirectionality, and channeling effects are analyzed. Both backward volume (BV) and Damon–Eshbach (DE) configurations are considered, where the lateral dimensions of the heavy-metal and ferromagnetic strips can differ. Calculations show notable nonreciprocal channeling of spin waves in both DE and BV modes. In the BV configuration, the dispersion is reciprocal with nontrivial localization of lateral confined modes. It is shown that the waves can be channeled into the zones in contact with the HM, where the Dzyaloshinskii–Moriya interaction is active. In the DE configuration, the waves exhibit nonreciprocal spin-wave dispersion, allowing unidirectional and channeled spin-wave propagation. The main results are compared to micromagnetic simulations, where an excellent agreement between both methods is obtained. These findings are relevant for envisioning advanced magnonic devices, enabling precise control over spin-wave propagation for innovative, low-power, high-speed information processing.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108057"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"International Advisory Board","authors":"","doi":"10.1016/S2211-3797(24)00759-9","DOIUrl":"10.1016/S2211-3797(24)00759-9","url":null,"abstract":"","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108074"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-Heating-Based channel thermal noise of advanced Sub-5-nm-Node nanosheet FET","authors":"Ilho Myeong ,&nbsp;Quan Nguyen-Gia ,&nbsp;Ickhyun Song","doi":"10.1016/j.rinp.2024.108059","DOIUrl":"10.1016/j.rinp.2024.108059","url":null,"abstract":"<div><div>In this paper, the self-heating effect and channel thermal noise (S_id) in stacked nanosheet gate-all-around (GAA) field effect transistor (FET) are investigated and discussed. In order to calculate channel thermal noise in radio-frequency (RF) operation, various factors such as electron mobility, temperature, and the gate capacitance is extracted through simulation. In addition, the channel length modulation (CLM) effect is analyzed to estimate the gate length, which is one of the important factors in obtaining S_id. After that, S_id is calculated, depending on the channel width (T_w) of the nanosheet FET. Then, the dependency of the signal to noise ratio (SNR) on T_w is addressed. Based on the findings of this work, relevant guidelines on T_w specification are discussed in terms of both S_id and SNR.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108059"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Logarithmic Bernstein functions for fractional Rosenau–Hyman equation with the Caputo–Hadamard derivative","authors":"M.H. Heydari ,&nbsp;F. Heydari ,&nbsp;O. Bavi ,&nbsp;M. Bayram","doi":"10.1016/j.rinp.2024.108055","DOIUrl":"10.1016/j.rinp.2024.108055","url":null,"abstract":"<div><div>In this study, the Caputo–Hadamard derivative is fittingly used to define a fractional form of the Rosenau–Hyman equation. To solve this equation, the orthonormal logarithmic Bernstein functions (BFs) are created as a suitable basis for handling this type of derivative. The primary benefit of these functions lies in the ease of computing their Hadamard fractional integral and derivative. These logarithmic functions, combined with the orthonormal Bernstein polynomials (BPs), are simultaneously employed to develop a hybrid strategy for solving the aforementioned equation. More precisely, the orthonormal logarithmic BFs are utilized to approximate the solution in the temporal domain and the orthonormal BPs are employed in the spatial domain. In addition, a matrix is extracted for the Hadamard integral of the orthonormal logarithmic BFs due to the implementation of the presented method. The effectiveness of the established scheme in finding accurate numerical solutions is evaluated through the resolution of three examples.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108055"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational analysis of heat transfer for hybrid nanofluid flow within a wavy lid-driven cavity with entropy generation and non-uniform heating","authors":"Muhammad Fawad Malik ,&nbsp;Yasir Ul Umair Bin Turabi ,&nbsp;Mohsan Raza ,&nbsp;Muhammad Imran ,&nbsp;Taseer Muhammad","doi":"10.1016/j.rinp.2024.108054","DOIUrl":"10.1016/j.rinp.2024.108054","url":null,"abstract":"<div><div>This study investigates entropy generation, mixed convection, and magnetohydrodynamic (MHD) effects in hybrid nanofluid flow within a wavy lid-driven cavity with non-uniform heated wall. This research addresses a significant problem in heat transfer system efficiency which is essential for uses such as solar energy collection, medical devices, and microelectronics cooling. The nondimensional governing equations are solved using the Finite Element Method (FEM) for various key parameters including Hartmann number (<span><math><mrow><mi>Ha</mi></mrow></math></span>), Grashof number (<span><math><mrow><mi>Gr</mi></mrow></math></span>), Reynolds number (<span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>), volume fraction (<span><math><mrow><mi>ϕ</mi></mrow></math></span>), number of undulations (<span><math><mrow><mi>N</mi></mrow></math></span>), wave amplitude (<span><math><mrow><mi>A</mi></mrow></math></span>), radius of cylinder (<span><math><mrow><mi>r</mi></mrow></math></span>) and inclined magnetic field (<span><math><mrow><mi>γ</mi></mrow></math></span>). Findings show that the enhancement of Grashof number<em>,</em> inclined angle, volume fraction and Reynolds number depict increasing flow magnitude but the number of undulations, radius of cylinder and Hartmann number cause a decay in flow strength. Increasing <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span> and <span><math><mrow><mi>Gr</mi></mrow></math></span> enhances heat transfer, with an average Nusselt number increase of 5.4 times when <span><math><mrow><mi>R</mi><mi>e</mi><mo>=</mo><mn>300</mn></mrow></math></span> and <span><math><mrow><mi>Gr</mi><mo>=</mo><msup><mrow><mn>10</mn></mrow><mn>6</mn></msup></mrow></math></span> compared to <span><math><mrow><mi>R</mi><mi>e</mi><mo>=</mo><mn>10</mn></mrow></math></span> and <span><math><mrow><mi>Gr</mi><mo>=</mo><msup><mrow><mn>10</mn></mrow><mn>3</mn></msup></mrow></math></span>. Entropy generation is significantly influenced by <span><math><mrow><mi>N</mi></mrow></math></span> with the highest total entropy observed at <span><math><mrow><mi>N</mi><mo>=</mo><mn>4</mn></mrow></math></span>. In contrast to previous studies, the novelty of this investigation lies in the unique geometric configuration featuring a wavy lid-driven cavity with an embedded cylinder and non-uniformly heated walls. This study of hybrid nanofluids and an angled magnetic field provides new paths for improving heat transfer and decreasing entropy generation. This study enhances previous literature by providing comprehensive quantitative insights into how they interact between those parameters opening the way for more efficient heat management in modern technological systems.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108054"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}