B. Langa, D. Sapkota, I. Lainez, R. Haight, B. Srijanto, L. Feldman, H. Hijazi, X. Zhu, L. Hu, M. Kim, K. Sardashti
Hybrid superconductor–semiconductor materials systems are promising candidates for quantum computing applications. Their integration into superconducting electronics has enabled on-demand voltage tunability at millikelvin temperatures. Ge quantum wells have been among the semiconducting platforms interfaced with superconducting Al to realize voltage tunable Josephson junctions. Here, we explore Nb as a superconducting material in direct contact with Ge channels by focusing on the solid-state reactions at the Nb/Ge interfaces. We employ Nb evaporation at cryogenic temperatures (∼100 K) to establish a baseline structure with atomically and chemically abrupt Nb/Ge interfaces. By conducting systematic photoelectron spectroscopy and transport measurements on Nb/Ge samples across varying annealing temperatures, we elucidated the influence of Ge out-diffusion on the ultimate performance of superconducting electronics. This study underlines the need for low-temperature growth to minimize chemical intermixing and band bending at the Nb/Ge interfaces.
混合超导体-半导体材料系统是量子计算应用的理想候选材料。将它们集成到超导电子器件中，可以在毫开尔文温度下实现按需电压可调。Ge 量子阱是与超导 Al 相连接的半导体平台之一，可实现电压可调的约瑟夫森结。在这里，我们通过重点研究铌/锗界面的固态反应，探索铌作为超导材料与 Ge 沟道的直接接触。我们采用在低温（∼100 K）下蒸发铌的方法，建立了具有原子和化学突变铌/锗界面的基线结构。通过对不同退火温度下的 Nb/Ge 样品进行系统的光电子能谱和传输测量，我们阐明了 Ge 外扩散对超导电子器件最终性能的影响。这项研究强调了低温生长的必要性，以尽量减少铌/锗界面上的化学混杂和带弯曲。
{"title":"Solid-state reactions at niobium–germanium interfaces in hybrid quantum electronics","authors":"B. Langa, D. Sapkota, I. Lainez, R. Haight, B. Srijanto, L. Feldman, H. Hijazi, X. Zhu, L. Hu, M. Kim, K. Sardashti","doi":"10.1063/5.0221366","DOIUrl":"https://doi.org/10.1063/5.0221366","url":null,"abstract":"Hybrid superconductor–semiconductor materials systems are promising candidates for quantum computing applications. Their integration into superconducting electronics has enabled on-demand voltage tunability at millikelvin temperatures. Ge quantum wells have been among the semiconducting platforms interfaced with superconducting Al to realize voltage tunable Josephson junctions. Here, we explore Nb as a superconducting material in direct contact with Ge channels by focusing on the solid-state reactions at the Nb/Ge interfaces. We employ Nb evaporation at cryogenic temperatures (∼100 K) to establish a baseline structure with atomically and chemically abrupt Nb/Ge interfaces. By conducting systematic photoelectron spectroscopy and transport measurements on Nb/Ge samples across varying annealing temperatures, we elucidated the influence of Ge out-diffusion on the ultimate performance of superconducting electronics. This study underlines the need for low-temperature growth to minimize chemical intermixing and band bending at the Nb/Ge interfaces.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"37 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renjie Shi, Liming Li, Shubin Zheng, Yizhou Mao, Xiaoxue An
Detecting pantographs remains a challenging task due to complex scenes, variable weather conditions, and noise interference. Existing pantograph detection methods struggle to effectively segment the complete shape of the pantograph from intricate backgrounds and adverse weather, and they often exhibit inadequate real-time performance. To address these challenges, we propose a novel pantograph segmentation method that leverages a deep learning multi-scale strip pooling attention mechanism. Our approach utilizes the PidNet semantic segmentation network as the baseline architecture, while we introduce a newly designed multi-scale strip pooling attention mechanism specifically for the detail extraction branch. The multi-scale strip convolution branch effectively extracts the pantograph pixel-level detail features, while the pooling branch effectively extracts the macroscopic features of the pantograph. The unique linear interpolation method effectively mitigates the influence of weather, enhancing segmentation accuracy while maintaining a lightweight structure. In the context aggregation branch, a multi-scale context aggregation module utilizing gated convolution has been developed to replace the original network’s module, which possesses strong pantograph positioning capabilities. In comparison to existing pantograph detection methods, our model demonstrates the ability to accurately segment the pantograph with a clearly defined shape, effectively filter out extraneous background noise, and exhibit high robustness to variations in illumination and weather conditions. In addition, a rich pantograph dataset was created, including various scenarios and weather conditions, which also enhanced the robustness of the model. When the IOU and accuracy are 92.91% and 96.04%, respectively, the inference speed can still exceed 30 FPS on a single 2080Ti GPU.
{"title":"Semantic segmentation algorithm for pantograph based on multi-scale strip pooling attention mechanism and application research","authors":"Renjie Shi, Liming Li, Shubin Zheng, Yizhou Mao, Xiaoxue An","doi":"10.1063/5.0230117","DOIUrl":"https://doi.org/10.1063/5.0230117","url":null,"abstract":"Detecting pantographs remains a challenging task due to complex scenes, variable weather conditions, and noise interference. Existing pantograph detection methods struggle to effectively segment the complete shape of the pantograph from intricate backgrounds and adverse weather, and they often exhibit inadequate real-time performance. To address these challenges, we propose a novel pantograph segmentation method that leverages a deep learning multi-scale strip pooling attention mechanism. Our approach utilizes the PidNet semantic segmentation network as the baseline architecture, while we introduce a newly designed multi-scale strip pooling attention mechanism specifically for the detail extraction branch. The multi-scale strip convolution branch effectively extracts the pantograph pixel-level detail features, while the pooling branch effectively extracts the macroscopic features of the pantograph. The unique linear interpolation method effectively mitigates the influence of weather, enhancing segmentation accuracy while maintaining a lightweight structure. In the context aggregation branch, a multi-scale context aggregation module utilizing gated convolution has been developed to replace the original network’s module, which possesses strong pantograph positioning capabilities. In comparison to existing pantograph detection methods, our model demonstrates the ability to accurately segment the pantograph with a clearly defined shape, effectively filter out extraneous background noise, and exhibit high robustness to variations in illumination and weather conditions. In addition, a rich pantograph dataset was created, including various scenarios and weather conditions, which also enhanced the robustness of the model. When the IOU and accuracy are 92.91% and 96.04%, respectively, the inference speed can still exceed 30 FPS on a single 2080Ti GPU.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"6 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electronic structure calculations of atoms and molecules are considered to be a promising application for quantum computers. Two key algorithms, the quantum phase estimation (QPE) and the variational quantum eigensolver (VQE), have been extensively studied. The condition that the energy of a dimer consisting of two monomers separated by a large distance should be equal to twice the energy of a monomer, known as size consistency, is essential in quantum chemical calculations. Recently, we reported that the size consistency condition can be violated by Trotterization in the unitary coupled cluster singles and doubles ansatz in the VQE when employing molecular orbitals delocalized to the dimer [Sugisaki et al., J. Comput. Chem. 45, 2204 (2024)]. It is well known that the full configuration interaction (full-CI) energy is invariant to arbitrary rotations of molecular orbitals, and therefore, the QPE-based full-CI should theoretically satisfy the size consistency. However, Trotterization of the time evolution operator can break the size consistency conditions. In this work, we investigated whether size consistency can be maintained with Trotterization of the time evolution operator in QPE-based full-CI calculations. Our numerical simulations revealed that size consistency in the QPE-based full-CI is not automatically violated by using molecular orbitals delocalized to the dimer, but employing an appropriate Trotter decomposition condition is crucial to maintain size consistency. We also report on the acceleration of QPE simulations through the sequential addition of ancillary qubits.
{"title":"Does the full configuration interaction method based on quantum phase estimation with Trotter decomposition satisfy the size consistency condition?","authors":"Kenji Sugisaki","doi":"10.1063/5.0223661","DOIUrl":"https://doi.org/10.1063/5.0223661","url":null,"abstract":"Electronic structure calculations of atoms and molecules are considered to be a promising application for quantum computers. Two key algorithms, the quantum phase estimation (QPE) and the variational quantum eigensolver (VQE), have been extensively studied. The condition that the energy of a dimer consisting of two monomers separated by a large distance should be equal to twice the energy of a monomer, known as size consistency, is essential in quantum chemical calculations. Recently, we reported that the size consistency condition can be violated by Trotterization in the unitary coupled cluster singles and doubles ansatz in the VQE when employing molecular orbitals delocalized to the dimer [Sugisaki et al., J. Comput. Chem. 45, 2204 (2024)]. It is well known that the full configuration interaction (full-CI) energy is invariant to arbitrary rotations of molecular orbitals, and therefore, the QPE-based full-CI should theoretically satisfy the size consistency. However, Trotterization of the time evolution operator can break the size consistency conditions. In this work, we investigated whether size consistency can be maintained with Trotterization of the time evolution operator in QPE-based full-CI calculations. Our numerical simulations revealed that size consistency in the QPE-based full-CI is not automatically violated by using molecular orbitals delocalized to the dimer, but employing an appropriate Trotter decomposition condition is crucial to maintain size consistency. We also report on the acceleration of QPE simulations through the sequential addition of ancillary qubits.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"5 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study addresses the magnetohydrodynamic flow of a squeezed ternary nanofluid between two horizontal parallel Riga plates. The importance of this problem lies in understanding the complex interactions between magnetic fields, nanofluid dynamics, and heat transfer, which are crucial for optimizing thermal management systems. This study utilizes a numerical approach, specifically a collocation method implemented in MATLAB, to solve the governing equations with high precision. Key results acquired indicate that the magnetic field and Riga plate actuator significantly enhance fluid velocity, whereas the variation in thermal conductivity, radiation, and viscous dissipation increases the temperature distribution. Quantitative analysis illustrates the impact of all these factors on skin friction and Nusselt number. Sensitivity analysis using the response surface methodology exhibits the conditions for optimized heat transfer. The novelty of this work lies in its comprehensive analysis of the magnetohydrodynamic flow in the presence of a microcantilever sensor, which provides deep understanding of optimization of heat transfer rates. This research offers a detailed examination of the combined effects of various physical phenomena and also validates them through graphical comparisons with existing studies.
{"title":"Numerical investigation and sensitivity analysis of MHD ternary nanofluid flow between perforated squeezed Riga plates under the surveillance of microcantilever sensor","authors":"Rajakumari Rammoorthi, Dhivya Mohanavel","doi":"10.1063/5.0218608","DOIUrl":"https://doi.org/10.1063/5.0218608","url":null,"abstract":"This study addresses the magnetohydrodynamic flow of a squeezed ternary nanofluid between two horizontal parallel Riga plates. The importance of this problem lies in understanding the complex interactions between magnetic fields, nanofluid dynamics, and heat transfer, which are crucial for optimizing thermal management systems. This study utilizes a numerical approach, specifically a collocation method implemented in MATLAB, to solve the governing equations with high precision. Key results acquired indicate that the magnetic field and Riga plate actuator significantly enhance fluid velocity, whereas the variation in thermal conductivity, radiation, and viscous dissipation increases the temperature distribution. Quantitative analysis illustrates the impact of all these factors on skin friction and Nusselt number. Sensitivity analysis using the response surface methodology exhibits the conditions for optimized heat transfer. The novelty of this work lies in its comprehensive analysis of the magnetohydrodynamic flow in the presence of a microcantilever sensor, which provides deep understanding of optimization of heat transfer rates. This research offers a detailed examination of the combined effects of various physical phenomena and also validates them through graphical comparisons with existing studies.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"4 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mostafizur Rahaman, Mahmudul Hasan, Rayan Md. Moinuddin, Md. Nasirul Islam
Due to the negative environmental impact, the usage of lead in perovskite solar cells has been a matter of concern. Moreover, a suitable replacement of Pb with similar optoelectrical properties is hard to find. MAPbI3 is the most common material that has been studied for solar PV applications. Compared to MAPbI3, Cs2TiBr6 and MASnI3 have been less studied. In this study, their potential in solar cell applications has been investigated. Titanium and tin are two materials that have been used in numerous studies as an alternative to Pb-based perovskite. However, the lack of optimization and combinations of electron transport layer (ETL) and hole transport layer (HTL) material choices leave a lot to be desired. In this study, two different perovskite absorber layers, Cs2TiBr6 and MASnI3, have been simulated, optimized, and compared with Pb-based MAPbI3, where La-doped BaSnO3 is used as ETL and CuSbS2 as HTL in identical cell architectures. La-doped BaSnO3 is well known for its high electron mobility and excellent optical properties, which makes it an ideal candidate for ETL. On the other hand, CuSbS2 has appropriate band alignment with perovskite materials and has a high absorption profile to be used as HTL. The simulations were analyzed by optimizing key parameters like absorber layer thickness, defect density, and temperature. The optimized device architecture reached the power conversion efficiencies (PCE) of 29.45% for MASnI3, followed by MAPbI3 (22.47%) and Cs2TiBr6 (21.96%). The result indicates that high performance lead-free perovskite cells are very much possible through proper material selection and optimization.
{"title":"Numerical optimization of lead-based and lead-free absorber materials for perovskite solar cell (PSC) architectures: A SCAPS-1D simulation","authors":"Mostafizur Rahaman, Mahmudul Hasan, Rayan Md. Moinuddin, Md. Nasirul Islam","doi":"10.1063/5.0217486","DOIUrl":"https://doi.org/10.1063/5.0217486","url":null,"abstract":"Due to the negative environmental impact, the usage of lead in perovskite solar cells has been a matter of concern. Moreover, a suitable replacement of Pb with similar optoelectrical properties is hard to find. MAPbI3 is the most common material that has been studied for solar PV applications. Compared to MAPbI3, Cs2TiBr6 and MASnI3 have been less studied. In this study, their potential in solar cell applications has been investigated. Titanium and tin are two materials that have been used in numerous studies as an alternative to Pb-based perovskite. However, the lack of optimization and combinations of electron transport layer (ETL) and hole transport layer (HTL) material choices leave a lot to be desired. In this study, two different perovskite absorber layers, Cs2TiBr6 and MASnI3, have been simulated, optimized, and compared with Pb-based MAPbI3, where La-doped BaSnO3 is used as ETL and CuSbS2 as HTL in identical cell architectures. La-doped BaSnO3 is well known for its high electron mobility and excellent optical properties, which makes it an ideal candidate for ETL. On the other hand, CuSbS2 has appropriate band alignment with perovskite materials and has a high absorption profile to be used as HTL. The simulations were analyzed by optimizing key parameters like absorber layer thickness, defect density, and temperature. The optimized device architecture reached the power conversion efficiencies (PCE) of 29.45% for MASnI3, followed by MAPbI3 (22.47%) and Cs2TiBr6 (21.96%). The result indicates that high performance lead-free perovskite cells are very much possible through proper material selection and optimization.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"71 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, we conducted an experiment in which a source material was sprayed onto a substrate with simultaneous N+ ion beam injections. Hexamethyldisiloxane (HMDSO) or tetraethyl orthosilicate (TEOS) was used as a source material. The energy of N+ ions was set at 100 eV. The substrate temperature was set at room temperature. As a result of each trial, a film was deposited on the substrate in both HMDSO and TEOS cases. The film was analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. We found that the film was silicon dioxide and nitrogen atoms (2–4 at. %) were included in the film. For comparison, a trial was also conducted in which hexamethyldigermane (HMDG) was sprayed onto a substrate with simultaneous 30 eV N+ ion beam injections. Although HMDG had no oxygen atoms in its molecule, XPS and FTIR results showed that the film was germanium oxide containing nitrogen (2 at. %).
在这项研究中，我们进行了一项实验，将源材料喷射到基底上，同时注入 N+ 离子束。我们使用六甲基二硅氧烷（HMDSO）或正硅酸四乙酯（TEOS）作为源材料。N+ 离子的能量设定为 100 eV。基底温度设定为室温。每次试验的结果都是在 HMDSO 和 TEOS 的基底上沉积出一层薄膜。通过 X 射线光电子能谱 (XPS) 和傅立叶变换红外光谱 (FTIR) 对薄膜进行了分析。我们发现薄膜是二氧化硅，其中含有氮原子（2-4%）。为了进行比较，我们还进行了一项试验，将六甲基二锗 (HMDG) 喷射到基底上，同时注入 30 eV N+ 离子束。虽然 HMDG 分子中没有氧原子，但 XPS 和傅立叶变换红外光谱结果表明，薄膜是含氮（2%）的氧化锗。
{"title":"Low-energy N+ ion beam induced chemical vapor deposition using tetraethyl orthosilicate, hexamethyldisiloxane, or hexamethyldigermane","authors":"Satoru Yoshimura, Takae Takeuchi, Masato Kiuchi","doi":"10.1063/5.0214908","DOIUrl":"https://doi.org/10.1063/5.0214908","url":null,"abstract":"In this study, we conducted an experiment in which a source material was sprayed onto a substrate with simultaneous N+ ion beam injections. Hexamethyldisiloxane (HMDSO) or tetraethyl orthosilicate (TEOS) was used as a source material. The energy of N+ ions was set at 100 eV. The substrate temperature was set at room temperature. As a result of each trial, a film was deposited on the substrate in both HMDSO and TEOS cases. The film was analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. We found that the film was silicon dioxide and nitrogen atoms (2–4 at. %) were included in the film. For comparison, a trial was also conducted in which hexamethyldigermane (HMDG) was sprayed onto a substrate with simultaneous 30 eV N+ ion beam injections. Although HMDG had no oxygen atoms in its molecule, XPS and FTIR results showed that the film was germanium oxide containing nitrogen (2 at. %).","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"9 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The advancement of rechargeable batteries for electronic devices requires continuous development of innovative materials for anodes, cathodes, and electrolytes. Li5GaO4 stands out as a promising electrode material for lithium-ion batteries, demonstrating swift Li-ion conductivity. Employing sophisticated computational simulation techniques based on classical potentials, we investigate the defect, diffusion, and dopant characteristics of Li5GaO4. Our simulations reveal that the Li Frenkel defect process possesses a minimum energy of 1.00 eV, while the Li–Ga anti-site isolated defect exhibits a higher energy. The Li–Ga anti-site cluster defect is favored over the Li–Ga anti-site isolated defect due to an exothermic binding of isolated defects forming a cluster (−2.28 eV). The projected long-range Li diffusion pathway aligns along the c-axis, featuring an activation energy of 0.42 eV. Notably, Na and Al emerge as the most promising isovalent dopants for the Li and Ge sites, respectively, with solution energies of −0.92 and 3.62 eV. Furthermore, the introduction of Si doping at the Ga site facilitates the formation of Li vacancies. This study offers crucial insights into the design of advanced materials, improving the capacity and performance of lithium-ion batteries, particularly addressing challenges associated with liquid electrolytes by utilizing solid electrolytes.
电子设备充电电池的发展需要不断开发创新的阳极、阴极和电解质材料。Li5GaO4 是一种很有前途的锂离子电池电极材料，具有快速的锂离子传导性。我们采用基于经典电位的复杂计算模拟技术，研究了 Li5GaO4 的缺陷、扩散和掺杂特性。模拟结果表明，锂 Frenkel 缺陷过程的最小能量为 1.00 eV，而锂镓反位孤立缺陷的能量更高。与镓锂反位孤立缺陷相比，镓锂反位簇缺陷更受青睐，这是因为孤立缺陷形成簇的放热结合（-2.28 eV）。预测的锂长程扩散路径沿 c 轴排列，活化能为 0.42 eV。值得注意的是，Na 和 Al 分别以-0.92 和 3.62 eV 的溶解能成为锂和 Ge 基底最有希望的异价掺杂剂。此外，在 Ga 位点引入硅掺杂剂有利于锂空位的形成。这项研究为设计先进材料、提高锂离子电池的容量和性能，特别是通过利用固体电解质解决与液态电解质相关的挑战提供了重要见解。
{"title":"Atomistic simulation study of Li5GaO4 for lithium-ion batteries","authors":"Sathiyamoorthy Mathushan, Poobalasingam Abiman, Poobalasuntharam Iyngaran, Navaratnarajah Kuganathan","doi":"10.1063/5.0213136","DOIUrl":"https://doi.org/10.1063/5.0213136","url":null,"abstract":"The advancement of rechargeable batteries for electronic devices requires continuous development of innovative materials for anodes, cathodes, and electrolytes. Li5GaO4 stands out as a promising electrode material for lithium-ion batteries, demonstrating swift Li-ion conductivity. Employing sophisticated computational simulation techniques based on classical potentials, we investigate the defect, diffusion, and dopant characteristics of Li5GaO4. Our simulations reveal that the Li Frenkel defect process possesses a minimum energy of 1.00 eV, while the Li–Ga anti-site isolated defect exhibits a higher energy. The Li–Ga anti-site cluster defect is favored over the Li–Ga anti-site isolated defect due to an exothermic binding of isolated defects forming a cluster (−2.28 eV). The projected long-range Li diffusion pathway aligns along the c-axis, featuring an activation energy of 0.42 eV. Notably, Na and Al emerge as the most promising isovalent dopants for the Li and Ge sites, respectively, with solution energies of −0.92 and 3.62 eV. Furthermore, the introduction of Si doping at the Ga site facilitates the formation of Li vacancies. This study offers crucial insights into the design of advanced materials, improving the capacity and performance of lithium-ion batteries, particularly addressing challenges associated with liquid electrolytes by utilizing solid electrolytes.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"22 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ze Guo, Weimeng Han, Zixu Guo, Hang Liu, Chuanjun Ma
High voltage circuit breakers are important equipment in power systems, and the valve motion of the chambers plays a role in the arc extinguishing performance of high-voltage circuit breakers. Therefore, in this paper, a 145 kV auto-expansion SF6 circuit breaker is taken as the research object, and a two-dimensional axisymmetric magnetohydrodynamic arc model considering valve motion process is established. The influence of different short circuit breaking conditions on the valve motion was studied. The results show that the backflow phenomenon of ablated steam is the main reason for the closure of the non-return valve, which plays an important role in opening the pressure relief valve. The closing time of the non-return valve is about 0.4 ms faster at a short circuit current of 40 kA than at a short circuit current of 36 kA.
高压断路器是电力系统中的重要设备，断路器室的阀门运动对高压断路器的灭弧性能有一定影响。因此，本文以 145 kV 自动膨胀 SF6 断路器为研究对象，建立了考虑阀运动过程的二维轴对称磁流体动力学电弧模型。研究了不同短路分断条件对阀运动的影响。结果表明，烧蚀蒸汽的倒流现象是止回阀关闭的主要原因，对开启泄压阀起着重要作用。短路电流为 40 kA 时，止回阀的关闭时间比短路电流为 36 kA 时快约 0.4 ms。
{"title":"Simulation of auto-expansion high voltage SF6 circuit breaker breaking process considering valve motion","authors":"Ze Guo, Weimeng Han, Zixu Guo, Hang Liu, Chuanjun Ma","doi":"10.1063/5.0222063","DOIUrl":"https://doi.org/10.1063/5.0222063","url":null,"abstract":"High voltage circuit breakers are important equipment in power systems, and the valve motion of the chambers plays a role in the arc extinguishing performance of high-voltage circuit breakers. Therefore, in this paper, a 145 kV auto-expansion SF6 circuit breaker is taken as the research object, and a two-dimensional axisymmetric magnetohydrodynamic arc model considering valve motion process is established. The influence of different short circuit breaking conditions on the valve motion was studied. The results show that the backflow phenomenon of ablated steam is the main reason for the closure of the non-return valve, which plays an important role in opening the pressure relief valve. The closing time of the non-return valve is about 0.4 ms faster at a short circuit current of 40 kA than at a short circuit current of 36 kA.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"9 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Giles Harrison, Ahmad A. Alkamali, Veronica Escobar-Ruiz, Keri A. Nicoll, Maarten H. P. Ambaum
Releasing charge into natural droplet systems such as fog and clouds offers a route to influence their properties. To facilitate charge release across a wide range of altitudes and meteorological circumstances—such as developing clouds—a charge emitter has been developed for integration with the conventional cloud-seeding flares carried by crewed cloud-seeding aircraft. This allows charge emitters to be used alongside, or instead of, conventional particle releasing flares. The charge emitter flare system is self-contained and self-powered, and includes internal monitoring and recording of its operating parameters. Using this “flare emitter” approach, successful charge emission has been demonstrated in level flight, at 3 km altitude, likely to have exceeded natural ion concentrations by several orders of magnitude. This quantitative verification of successful charge emission can underpin further physically based experiments on the effectiveness of charge release in cloud seeding.
{"title":"Providing charge emission for cloud seeding aircraft","authors":"R. Giles Harrison, Ahmad A. Alkamali, Veronica Escobar-Ruiz, Keri A. Nicoll, Maarten H. P. Ambaum","doi":"10.1063/5.0227533","DOIUrl":"https://doi.org/10.1063/5.0227533","url":null,"abstract":"Releasing charge into natural droplet systems such as fog and clouds offers a route to influence their properties. To facilitate charge release across a wide range of altitudes and meteorological circumstances—such as developing clouds—a charge emitter has been developed for integration with the conventional cloud-seeding flares carried by crewed cloud-seeding aircraft. This allows charge emitters to be used alongside, or instead of, conventional particle releasing flares. The charge emitter flare system is self-contained and self-powered, and includes internal monitoring and recording of its operating parameters. Using this “flare emitter” approach, successful charge emission has been demonstrated in level flight, at 3 km altitude, likely to have exceeded natural ion concentrations by several orders of magnitude. This quantitative verification of successful charge emission can underpin further physically based experiments on the effectiveness of charge release in cloud seeding.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"5 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The significant disparities in physical and chemical properties between aluminum alloy and high-strength steel pose substantial challenges for conventional friction joining techniques. To address this issue, this study proposes a novel approach utilizing inertial friction welding with an interlayer to join these dissimilar materials. A CrCoNi medium entropy alloy sheet was selected as the interlayer due to its intermediate melting point, thermal conductivity, strength, and surface hardness between 6061-T6 aluminum alloy and 42CrMo steel, as well as its high element mixing entropy. These properties were deemed crucial for balancing interface heat generation and regulation the formation of intermetallic compounds. The experimental procedure involved embedding the CrCoNi sheet into the end face of the 6061-T6 aluminum alloy, followed by the application of IFW to join the aluminum alloy with 42CrMo high-strength steel. This investigation focuses on examining the effects of three distinct friction speeds (3800, 4000, and 4200 rpm) on the microstructural characteristics and mechanical properties of the regulating joints with the CrCoNi interlayer. Results demonstrate that the CrCoNi enhances the temperature at the steel-side interface through friction with 42CrMo steel and 6061-T6 aluminum, combined with adjustments in the friction sequence and duration, promoting plastic deformation. The axial transfer of heat creates a temperature gradient at the joint, enabling low-temperature welding on the aluminum side and forming a mechanical interlocking structure at the interface. The diffusion of Cr, Co, and Ni elements regulates the type and thickness of interfacial intermetallic compounds, ultimately enhancing the joint's strength. The thickness of the intermetallic compounds AlNi3, FeAl3, AlCo, and Fe2Al5 formed at the interface is less than 2 µm. A phase transformation occurred at the 42CrMo high-strength steel interface, leading to the formation of numerous needle-like martensites, which increased the Vickers hardness in the welding seam to 763.9 HV. The joint's tensile strength initially increased and then decreased with increasing friction speed, reaching a maximum of 168.7 MPa at 4000 rpm, which is more than 60% of the aluminum alloy base material's tensile strength.
{"title":"Enhanced inertia friction welding of aluminum alloy and high-strength steel using CrCoNi interlayer: Microstructural and mechanical characterization","authors":"Qiming Jiang, Wei Wu, Hongrui Yang, Kunhang Li, Guangchuan Zhang, Hong Huang","doi":"10.1063/5.0221957","DOIUrl":"https://doi.org/10.1063/5.0221957","url":null,"abstract":"The significant disparities in physical and chemical properties between aluminum alloy and high-strength steel pose substantial challenges for conventional friction joining techniques. To address this issue, this study proposes a novel approach utilizing inertial friction welding with an interlayer to join these dissimilar materials. A CrCoNi medium entropy alloy sheet was selected as the interlayer due to its intermediate melting point, thermal conductivity, strength, and surface hardness between 6061-T6 aluminum alloy and 42CrMo steel, as well as its high element mixing entropy. These properties were deemed crucial for balancing interface heat generation and regulation the formation of intermetallic compounds. The experimental procedure involved embedding the CrCoNi sheet into the end face of the 6061-T6 aluminum alloy, followed by the application of IFW to join the aluminum alloy with 42CrMo high-strength steel. This investigation focuses on examining the effects of three distinct friction speeds (3800, 4000, and 4200 rpm) on the microstructural characteristics and mechanical properties of the regulating joints with the CrCoNi interlayer. Results demonstrate that the CrCoNi enhances the temperature at the steel-side interface through friction with 42CrMo steel and 6061-T6 aluminum, combined with adjustments in the friction sequence and duration, promoting plastic deformation. The axial transfer of heat creates a temperature gradient at the joint, enabling low-temperature welding on the aluminum side and forming a mechanical interlocking structure at the interface. The diffusion of Cr, Co, and Ni elements regulates the type and thickness of interfacial intermetallic compounds, ultimately enhancing the joint's strength. The thickness of the intermetallic compounds AlNi3, FeAl3, AlCo, and Fe2Al5 formed at the interface is less than 2 µm. A phase transformation occurred at the 42CrMo high-strength steel interface, leading to the formation of numerous needle-like martensites, which increased the Vickers hardness in the welding seam to 763.9 HV. The joint's tensile strength initially increased and then decreased with increasing friction speed, reaching a maximum of 168.7 MPa at 4000 rpm, which is more than 60% of the aluminum alloy base material's tensile strength.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"56 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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