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":"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":"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}

{"title":"Convergent laser beam shapes: Unveiling the dynamics of Laser-induced elastic waves in composite materials","authors":"Alireza Zarei ,&nbsp;Gang Li ,&nbsp;Farhang Pourboghrat ,&nbsp;Srikanth Pilla","doi":"10.1016/j.rinp.2024.108061","DOIUrl":"10.1016/j.rinp.2024.108061","url":null,"abstract":"<div><div>Overcoming the low signal-to-noise ratio (SNR) in laser ultrasonic testing of composite materials remains a significant challenge. Current efforts focus on enhancing SNR by inserting more energy into the material through temporal and/or spatial modulation of the laser beam. However, potential SNR improvements through wave convergence and wave energy manipulation have been overlooked. This paper addresses this gap by demonstrating the convergence of different wave types to a designated point and by showing the feasibility of directing absorbed laser energy into a specific wave type through spatial modulation of the laser beam. To achieve this, mathematical expressions for the convergent laser beams are derived. Various laser beam profiles are then introduced to the thermoelastic equations and solved using the finite element method. The sample under investigation is a transversely isotropic unidirectional carbon fiber reinforced plastic, characterized by anisotropic thermal expansion coefficients and thermal conductivities. Results reveal pronounced convergence of the intended wave type at the center due to laser beam shaping. This study showcases the ability to direct absorbed laser energy toward a specific wave type through spatial modulation of the laser beam and highlights the role of material anisotropy in energy focusing.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108061"},"PeriodicalIF":4.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743740","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":"Sensitivity of photovoltaic cells efficiency to initial conditions in various aggregation designs","authors":"Baharak Mohamad Jafari Navadel ,&nbsp;Esfandyar Faizi ,&nbsp;Baharam Ahansaz ,&nbsp;Jaber Jahanbin Sardroodi","doi":"10.1016/j.rinp.2024.108052","DOIUrl":"10.1016/j.rinp.2024.108052","url":null,"abstract":"<div><div>It is thought that nature already exploits quantum mechanical properties to increase the efficiency of solar energy harvesting devices. Thus, the operation of these devices can be enhanced by clever design of a nanoscopic, quantum mechanical system where the quantum coherence plays a crucial role in this process. In this investigation, we develop a donor–acceptor two level trap dipole model converging the key role of quantum coherence and aggregation effects along with different initial states. Our analysis reveals that quenching unwanted emissions is achievable by preparing the system in specific initial state under the effect of optimal spatial aggregation. Interestingly it is observed that characterizing aggregation-induced properties and quantum effects of bandgap engineering can increase the power enhancement up to 35.87% compared with classical counterparts. This encouraging trend suggests a promising novel design aspect of nature-mimicking photovoltaic devices.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"68 ","pages":"Article 108052"},"PeriodicalIF":4.4,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722323","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":"Monolayer and bilayer BP as efficient optoelectronic materials in visible and ultraviolet regions","authors":"Somayeh Behzad","doi":"10.1016/j.rinp.2024.108048","DOIUrl":"10.1016/j.rinp.2024.108048","url":null,"abstract":"<div><div>Hexagonal boron phosphide (BP) shows significant promise for optoelectronic applications due to its high carrier mobility and moderate band gap. Strain inevitably occurs during the synthesis of two-dimensional (2D) nanomaterials. In this work, a detailed study on the strain-dependent phonon dispersion and optical properties of monolayer and bilayer BP was performed. The calculated phonon dispersion curves demonstrate that both monolayer and bilayer BP systems remain dynamically stable under tensile strain. By increasing tensile strain, the LO and TO modes soften and the phonon band gap between optical and acoustic modes becomes narrower. The LO and TO modes display expanded phonon spectra under large tensile strains in contrast to the ZA mode. The absorption edge of bilayer BP is located around 0.6 eV, lower in energy with respect to the monolayer BP at ∼ 0.8 eV. The results indicate that the optical absorption may be enhanced by applying the compressive strain. With their broad absorption range and strain-tunable absorption strength and phononic properties, monolayer and bilayer BP are highly promising for next-generation nanodevices.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"67 ","pages":"Article 108048"},"PeriodicalIF":4.4,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699209","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}