Avalanche photodiodes (APDs) produce noise during operation, which affects the device performance. However, the previous research on its noise is mainly theoretical analysis and is only reflected as optical noise. Therefore, according to the characteristics of APD material and the mechanism of noise generation, the main noise of the device is analyzed in this paper. First, the test method of noise in APDs is established, including testing of dark noise, optical noise, and multiplication noise in high frequency bands. The main noises in APDs are 1/f noise, thermal noise, shot noise, generation recombination noise, and multiplication shot noise, and shot noise is suppressed by Fermi–Dirac distribution and Coulomb action. Second, the reliability of APDs is evaluated by measuring and analyzing the noise parameters of the device through thermal aging experiments. It is concluded that the defects introduced by thermal aging can be reflected by the change in noise, which is consistent with the results in the literature. This method can comprehensively obtain the noise in APDs, which is helpful to improve the working efficiency, life, and reliability of the device.
{"title":"Analysis of noise and its characteristics in avalanche photodiode","authors":"XiaoFei Jia, Qun Wei, Yan Zhu, WenPeng Zhang","doi":"10.1063/5.0229293","DOIUrl":"https://doi.org/10.1063/5.0229293","url":null,"abstract":"Avalanche photodiodes (APDs) produce noise during operation, which affects the device performance. However, the previous research on its noise is mainly theoretical analysis and is only reflected as optical noise. Therefore, according to the characteristics of APD material and the mechanism of noise generation, the main noise of the device is analyzed in this paper. First, the test method of noise in APDs is established, including testing of dark noise, optical noise, and multiplication noise in high frequency bands. The main noises in APDs are 1/f noise, thermal noise, shot noise, generation recombination noise, and multiplication shot noise, and shot noise is suppressed by Fermi–Dirac distribution and Coulomb action. Second, the reliability of APDs is evaluated by measuring and analyzing the noise parameters of the device through thermal aging experiments. It is concluded that the defects introduced by thermal aging can be reflected by the change in noise, which is consistent with the results in the literature. This method can comprehensively obtain the noise in APDs, which is helpful to improve the working efficiency, life, and reliability of the device.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"60 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224433","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}
Deep learning techniques provide a new approach to the design and optimization of electromagnetic metamaterials. This study used a convolutional neural network and long short-term memory (CNN–LSTM) hybrid network to design and optimize a broadband metamaterial reflective linear polarization converter. The data augmentation method was also employed in few-shot learning to reduce optimization costs and improve model prediction performance. With the inverse prediction, a linear polarization converter that perfectly covers the Ku-band was obtained and fabricated with flexible printed circuit technology. Both simulation and experimental results indicate that this network can accurately predict the structural parameters. The polarization converter not only achieves remarkable broadband polarization conversion efficiency spanning the 2.2–18 GHz range but also maintains precise cross-polarization control across the entire Ku-band. The mean polarization conversion ratio in the Ku-band was calculated to be an impressive 99.69%. Finally, the mechanism of polarization conversion and the influence of each structural parameter on its performance further verify the optimality of the inverse design model. The use of CNN–LSTM deep learning methods significantly simplified the design process of electromagnetic metamaterials, reducing design costs while ensuring high design precision and excellent performance.
深度学习技术为电磁超材料的设计和优化提供了一种新方法。本研究使用卷积神经网络和长短期记忆（CNN-LSTM）混合网络来设计和优化宽带超材料反射线性极化转换器。在少次学习中还采用了数据增强方法，以降低优化成本并提高模型预测性能。通过反向预测，获得了完美覆盖 Ku 波段的线性偏振转换器，并利用柔性印刷电路技术制造了该转换器。仿真和实验结果都表明，该网络能准确预测结构参数。该偏振转换器不仅在 2.2-18 GHz 范围内实现了出色的宽带偏振转换效率，而且在整个 Ku 波段内保持了精确的交叉偏振控制。根据计算，Ku 波段的平均极化转换率达到了惊人的 99.69%。最后，极化转换机制以及各结构参数对其性能的影响进一步验证了反向设计模型的最优性。CNN-LSTM 深度学习方法的使用大大简化了电磁超材料的设计过程，降低了设计成本，同时确保了高设计精度和优异性能。
{"title":"Broadband metamaterial linear polarization converter designed by a hybrid neural network with data augmentation","authors":"Junyu Hua, Xiaodong He","doi":"10.1063/5.0224049","DOIUrl":"https://doi.org/10.1063/5.0224049","url":null,"abstract":"Deep learning techniques provide a new approach to the design and optimization of electromagnetic metamaterials. This study used a convolutional neural network and long short-term memory (CNN–LSTM) hybrid network to design and optimize a broadband metamaterial reflective linear polarization converter. The data augmentation method was also employed in few-shot learning to reduce optimization costs and improve model prediction performance. With the inverse prediction, a linear polarization converter that perfectly covers the Ku-band was obtained and fabricated with flexible printed circuit technology. Both simulation and experimental results indicate that this network can accurately predict the structural parameters. The polarization converter not only achieves remarkable broadband polarization conversion efficiency spanning the 2.2–18 GHz range but also maintains precise cross-polarization control across the entire Ku-band. The mean polarization conversion ratio in the Ku-band was calculated to be an impressive 99.69%. Finally, the mechanism of polarization conversion and the influence of each structural parameter on its performance further verify the optimality of the inverse design model. The use of CNN–LSTM deep learning methods significantly simplified the design process of electromagnetic metamaterials, reducing design costs while ensuring high design precision and excellent performance.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"9 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224432","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 essence of fluid phase transition is the jump of physical properties distinctly induced by shock waves in the hard-sphere model. Due to the strong impact of the wave, the internal freedoms of molecules are stimulated, releasing tremendous energy that commonly triggers the phase transition. Conversely, typical thermal and dynamic jumps can be described by the Rankine–Hugoniot conditions based on the Euler equation. In the theoretical simulation, the initial density and rotational freedoms of molecules are directly regarded as the primary factors to affect processes of phase transition. However, the influence of vibrational freedom in molecules has not been discussed yet. As the increasing temperature can gradually excite the affection of vibrational freedom, it is unwise to assume that the temperature element is constant in the theory. What would be a suitable model that accurately reflects the relationship between temperature and affection from vibrational freedom? The non-limited model has been courageously attempted with the temperature range from T0 to 6T0 (T0 is unperturbed temperature). We have found that the vibrational freedom can have a great effect on properties during phase transition processes.
{"title":"Non-limited vibrational effect on shock-induced phase transitions of condensed fluid in hard-sphere model","authors":"Yue Zheng, Junjun Xu, Ke Tang","doi":"10.1063/5.0231113","DOIUrl":"https://doi.org/10.1063/5.0231113","url":null,"abstract":"The essence of fluid phase transition is the jump of physical properties distinctly induced by shock waves in the hard-sphere model. Due to the strong impact of the wave, the internal freedoms of molecules are stimulated, releasing tremendous energy that commonly triggers the phase transition. Conversely, typical thermal and dynamic jumps can be described by the Rankine–Hugoniot conditions based on the Euler equation. In the theoretical simulation, the initial density and rotational freedoms of molecules are directly regarded as the primary factors to affect processes of phase transition. However, the influence of vibrational freedom in molecules has not been discussed yet. As the increasing temperature can gradually excite the affection of vibrational freedom, it is unwise to assume that the temperature element is constant in the theory. What would be a suitable model that accurately reflects the relationship between temperature and affection from vibrational freedom? The non-limited model has been courageously attempted with the temperature range from T0 to 6T0 (T0 is unperturbed temperature). We have found that the vibrational freedom can have a great effect on properties during phase transition processes.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"8 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185398","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}
Internal wave is essentially a gravity wave induced by the layered structure of water (e.g., density stable layering), with its maximum amplitude occurring within the ocean. Similar to surface waves, internal waves have significant influence on the strength and stability of a submerged body as an external factor. Meanwhile, combined shells are exposed to complicated loads under internal waves, and edge stress is dominant. In this study, the edge stresses of combined shell (typical hemisphere–cylinder combined shell and unfolded sphere–cylinder combined shell) under internal waves were analyzed. Indeed, a semi-empirical, semi-theoretical formula for the edge stress of combined shells (typical hemisphere–cylinder combined shell and unfolded sphere–cylinder combined shell) has been proposed. In this study, the semi-empirical, semi-theoretical formula was corrected by introducing internal wave loads, with the depth of the internal wave taken into consideration. In addition, the corrected formula was verified by finite element analysis, and a simplified equation for the calculation of edge stress of the combined shell under internal waves was developed, with errors in a rational range.
{"title":"Analysis of edge stress of combined shell under internal waves","authors":"Yiqiong Cui","doi":"10.1063/5.0225674","DOIUrl":"https://doi.org/10.1063/5.0225674","url":null,"abstract":"Internal wave is essentially a gravity wave induced by the layered structure of water (e.g., density stable layering), with its maximum amplitude occurring within the ocean. Similar to surface waves, internal waves have significant influence on the strength and stability of a submerged body as an external factor. Meanwhile, combined shells are exposed to complicated loads under internal waves, and edge stress is dominant. In this study, the edge stresses of combined shell (typical hemisphere–cylinder combined shell and unfolded sphere–cylinder combined shell) under internal waves were analyzed. Indeed, a semi-empirical, semi-theoretical formula for the edge stress of combined shells (typical hemisphere–cylinder combined shell and unfolded sphere–cylinder combined shell) has been proposed. In this study, the semi-empirical, semi-theoretical formula was corrected by introducing internal wave loads, with the depth of the internal wave taken into consideration. In addition, the corrected formula was verified by finite element analysis, and a simplified equation for the calculation of edge stress of the combined shell under internal waves was developed, with errors in a rational range.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"20 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185397","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}
Mohamed S. Abdo, Muhammad A. Shar, Ahmed Fouly, Mushtaq A. Dar, Hany S. Abdo
This study investigates the enhancement of mechanical and tribological behavior in polymethyl methacrylate (PMMA) composites reinforced with graphene oxide (GO) as a solid lubricant filler for advanced biomedical applications, particularly dental implants. PMMA/GO composites were prepared with varying weight percentages of GO (0, 0.2, 0.5, 0.7, and 1 wt. %) to assess their impact on material performance. A noteworthy improvement in both tensile strength and Young’s modulus was detected, reaching up to 141% and 10.6%, respectively, at optimized GO loadings of 1%. Microstructural analysis utilizing scanning electron microscopy for the worn surface revealed enhanced dispersion and interfacial adhesion between GO and the PMMA matrix, reinforcing mechanical coherence. Tribological properties also demonstrated enhancement, with PMMA composites containing 1 wt. % GO exhibiting optimal mechanical and tribological characteristics compared to lower weight fractions. Moreover, microscopic examination revealed a shift in the wear mechanism of the PMMA-GO composite, which was attributed to the lower friction coefficient obtained by GO integration.
本研究探讨了用氧化石墨烯（GO）作为固体润滑剂填料增强聚甲基丙烯酸甲酯（PMMA）复合材料的机械和摩擦学性能，用于先进的生物医学应用，尤其是牙科植入物。我们制备了不同重量百分比（0、0.2、0.5、0.7 和 1 重量百分比）的 PMMA/GO 复合材料，以评估它们对材料性能的影响。拉伸强度和杨氏模量均有显著提高，在 GO 的优化负载量为 1%时，拉伸强度和杨氏模量分别提高了 141% 和 10.6%。利用扫描电子显微镜对磨损表面进行的微观结构分析表明，GO 和 PMMA 基体之间的分散性和界面粘附性得到了增强，从而加强了机械一致性。摩擦学特性也得到了增强，与较低重量分数相比，含有 1 重量百分比 GO 的 PMMA 复合材料表现出最佳的机械和摩擦学特性。此外，显微镜检查显示，PMMA-GO 复合材料的磨损机制发生了变化，这归因于 GO 集成降低了摩擦系数。
{"title":"Experimental investigation on the tribo-mechanical behavior of PMMA reinforced by solid lubricant filler for dental implant applications","authors":"Mohamed S. Abdo, Muhammad A. Shar, Ahmed Fouly, Mushtaq A. Dar, Hany S. Abdo","doi":"10.1063/5.0225107","DOIUrl":"https://doi.org/10.1063/5.0225107","url":null,"abstract":"This study investigates the enhancement of mechanical and tribological behavior in polymethyl methacrylate (PMMA) composites reinforced with graphene oxide (GO) as a solid lubricant filler for advanced biomedical applications, particularly dental implants. PMMA/GO composites were prepared with varying weight percentages of GO (0, 0.2, 0.5, 0.7, and 1 wt. %) to assess their impact on material performance. A noteworthy improvement in both tensile strength and Young’s modulus was detected, reaching up to 141% and 10.6%, respectively, at optimized GO loadings of 1%. Microstructural analysis utilizing scanning electron microscopy for the worn surface revealed enhanced dispersion and interfacial adhesion between GO and the PMMA matrix, reinforcing mechanical coherence. Tribological properties also demonstrated enhancement, with PMMA composites containing 1 wt. % GO exhibiting optimal mechanical and tribological characteristics compared to lower weight fractions. Moreover, microscopic examination revealed a shift in the wear mechanism of the PMMA-GO composite, which was attributed to the lower friction coefficient obtained by GO integration.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"7 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185401","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}
We have theoretically and experimentally demonstrated the feasibility of achieving ultra-low dark current in CpBnn type detectors based on a double-barrier InAs/GaSb/AlSb type-II superlattice. By employing a structure that separates the absorption region and depletion region, the diffusion, recombination, tunneling, and surface dark currents of the photodetector (PD) have been suppressed. Experimental validation has shown that a detector with a diameter of 500 µm at a bias voltage of −0.5 V exhibits a dark current density of 2.5 × 10−6 A/cm2 at the operating temperature of 300 K. The development of PD with low dark current has paved the way for applications with high demands for low noise in the fields of gravitational wave detection and astronomical observation.
我们从理论和实验上证明了在基于 InAs/GaSb/AlSb II 型双势垒超晶格的 CpBnn 型探测器中实现超低暗电流的可行性。通过采用吸收区和耗尽区分离的结构，光电探测器（PD）的扩散、重组、隧道和表面暗电流都得到了抑制。实验验证表明，直径为 500 微米的探测器在-0.5 V 的偏置电压下，工作温度为 300 K 时的暗电流密度为 2.5 × 10-6 A/cm2。
{"title":"Low dark current Sb-based short-wavelength infrared photodetector","authors":"Mingming Li, Yifan Cheng, Xiangyu Zhang, Ye Zhang, Dongwei Jiang, Zhigang Song, Wanhua Zheng","doi":"10.1063/5.0207138","DOIUrl":"https://doi.org/10.1063/5.0207138","url":null,"abstract":"We have theoretically and experimentally demonstrated the feasibility of achieving ultra-low dark current in CpBnn type detectors based on a double-barrier InAs/GaSb/AlSb type-II superlattice. By employing a structure that separates the absorption region and depletion region, the diffusion, recombination, tunneling, and surface dark currents of the photodetector (PD) have been suppressed. Experimental validation has shown that a detector with a diameter of 500 µm at a bias voltage of −0.5 V exhibits a dark current density of 2.5 × 10−6 A/cm2 at the operating temperature of 300 K. The development of PD with low dark current has paved the way for applications with high demands for low noise in the fields of gravitational wave detection and astronomical observation.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"6 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224436","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}
To address the dual problems of fuel reliance and air pollution, this study describes the design of a wireless ground to vehicle charging system powered by solar energy and specifically designed for electric vehicle (EV) charging stations. As the number of electric vehicles on the road steadily rises, they present a viable way to cut travel expenses by switching from conventional fuel to electricity, which is a more economical and sustainable option. With the introduction of a wireless EV charging system, this creative solution does away with the need for external power sources and permits continuous charging without interfering with driving. Utilizing solar power, the charging system incorporates solar panels, batteries, circuit regulators, boost converters, receiver and transmitter copper coils, AC/DC converters, microcontrollers (such as ATmega), LCD screens, and circuit regulators. This study describes a technique that shows that charging electric cars while driving is feasible and eliminates the need to stop. This technology for wireless solar electric vehicle charging presents a forward-thinking approach to sustainable mobility by providing a workable solution that can be easily included in the road infrastructure. For the wireless charging, in addition, various coil designs are suggested.
{"title":"Design of wireless charging system for E-Vehicle","authors":"Shweta L. Tiwari, S. R. Gaigowal, Kiran Raut","doi":"10.1063/5.0218429","DOIUrl":"https://doi.org/10.1063/5.0218429","url":null,"abstract":"To address the dual problems of fuel reliance and air pollution, this study describes the design of a wireless ground to vehicle charging system powered by solar energy and specifically designed for electric vehicle (EV) charging stations. As the number of electric vehicles on the road steadily rises, they present a viable way to cut travel expenses by switching from conventional fuel to electricity, which is a more economical and sustainable option. With the introduction of a wireless EV charging system, this creative solution does away with the need for external power sources and permits continuous charging without interfering with driving. Utilizing solar power, the charging system incorporates solar panels, batteries, circuit regulators, boost converters, receiver and transmitter copper coils, AC/DC converters, microcontrollers (such as ATmega), LCD screens, and circuit regulators. This study describes a technique that shows that charging electric cars while driving is feasible and eliminates the need to stop. This technology for wireless solar electric vehicle charging presents a forward-thinking approach to sustainable mobility by providing a workable solution that can be easily included in the road infrastructure. For the wireless charging, in addition, various coil designs are suggested.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"53 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185399","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}
Xiangyu Xu, Xigui Tao, Yingxiang Wu, Yunke Lu, Yan Liu, Ji Zhang, Yushuai Zhang
The projectile deflects and even ricochets after an oblique impact on the concrete. However, research on the oblique impact of projectiles on concrete targets mainly focuses on oblique penetration and the critical ricochet angle, and there are few experimental studies on ricochets. Deflection and its influencing factors remain undefined. This study conducted experiments and LS-DYNA numerical simulations on projectiles obliquely impacting C60 concrete targets. The experimental research visually revealed deflection and ricochet phenomena after the oblique impact. The ricochet caused by large-angle impacts can effectively reduce the damaged area of concrete targets. Subsequently, the main governing parameters affecting the deflection angle of the projectile were identified through dimensional analysis, and a sensitivity analysis was performed on these parameters using an orthogonal experimental design. On this basis, the influence of the incident angle, impact velocity, and projectile length-to-diameter ratio on the projectile deflection was further clarified. The results showed that the maximum deflection angle was achieved when a 30 mm caliber projectile obliquely impacted a C60 concrete at an incident angle of ∼45°. In the case of ricochets, the deflection angle increased with an increase in the impact velocity and decreased with an increase in the length-to-diameter ratio. This study aids in predicting and controlling projectile deflection and provides a reference for the innovative design of concrete protective structures.
{"title":"Deflection characteristics and influencing factors of projectile oblique impact on concrete targets","authors":"Xiangyu Xu, Xigui Tao, Yingxiang Wu, Yunke Lu, Yan Liu, Ji Zhang, Yushuai Zhang","doi":"10.1063/5.0220438","DOIUrl":"https://doi.org/10.1063/5.0220438","url":null,"abstract":"The projectile deflects and even ricochets after an oblique impact on the concrete. However, research on the oblique impact of projectiles on concrete targets mainly focuses on oblique penetration and the critical ricochet angle, and there are few experimental studies on ricochets. Deflection and its influencing factors remain undefined. This study conducted experiments and LS-DYNA numerical simulations on projectiles obliquely impacting C60 concrete targets. The experimental research visually revealed deflection and ricochet phenomena after the oblique impact. The ricochet caused by large-angle impacts can effectively reduce the damaged area of concrete targets. Subsequently, the main governing parameters affecting the deflection angle of the projectile were identified through dimensional analysis, and a sensitivity analysis was performed on these parameters using an orthogonal experimental design. On this basis, the influence of the incident angle, impact velocity, and projectile length-to-diameter ratio on the projectile deflection was further clarified. The results showed that the maximum deflection angle was achieved when a 30 mm caliber projectile obliquely impacted a C60 concrete at an incident angle of ∼45°. In the case of ricochets, the deflection angle increased with an increase in the impact velocity and decreased with an increase in the length-to-diameter ratio. This study aids in predicting and controlling projectile deflection and provides a reference for the innovative design of concrete protective structures.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"26 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224434","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 paper discusses the application of reactive multiparticle collision (RMPC) dynamics, a particle-based method, to epidemic models. First, we consider a susceptible-infectious-recovered framework to obtain data on contacts of susceptibles with infectious people in a population. It is found that the number of contacts increases and the contact duration decreases with increases in the disease transmission rate and average population speed. Next, we obtain reinfection statistics for a general infectious disease from RMPC simulations of a susceptible-infectious-recovered-susceptible model. Finally, we simulate a susceptible-exposed-infectious-recovered model and gather the exposure, infection, and recovery time for the individuals in the population under consideration. It is worth mentioning that we can collect data in the form of average contact duration, average initial infection time, etc., from RMPC simulations of these models, which is not possible with population-based stochastic models, or deterministic systems. This study provides quantitative insights on the potential of RMPC to simulate epidemic models and motivates future efforts for its application in the field of mathematical epidemiology.
{"title":"On the use of reactive multiparticle collision dynamics to gather particulate level information from simulations of epidemic models","authors":"Zaib Un Nisa Memon, Katrin Rohlf","doi":"10.1063/5.0223361","DOIUrl":"https://doi.org/10.1063/5.0223361","url":null,"abstract":"This paper discusses the application of reactive multiparticle collision (RMPC) dynamics, a particle-based method, to epidemic models. First, we consider a susceptible-infectious-recovered framework to obtain data on contacts of susceptibles with infectious people in a population. It is found that the number of contacts increases and the contact duration decreases with increases in the disease transmission rate and average population speed. Next, we obtain reinfection statistics for a general infectious disease from RMPC simulations of a susceptible-infectious-recovered-susceptible model. Finally, we simulate a susceptible-exposed-infectious-recovered model and gather the exposure, infection, and recovery time for the individuals in the population under consideration. It is worth mentioning that we can collect data in the form of average contact duration, average initial infection time, etc., from RMPC simulations of these models, which is not possible with population-based stochastic models, or deterministic systems. This study provides quantitative insights on the potential of RMPC to simulate epidemic models and motivates future efforts for its application in the field of mathematical epidemiology.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"310 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224435","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}
Orbital currents in light metals or metal oxides without the strong spin–orbit coupling have become an important means to achieve low-power magnetization switching in spin–orbitronic devices. The orbital magnetoresistance (OMR) originated from orbital current represents a useful strategy to explore the interaction between the orbital angular momentum (OAM) and the local magnetic moment. However, systematic research works on the enhancement of OMR and the mechanism of OAM transport are seldom reported. In this study, we report a synergistically enhanced magnetoresistance effect induced by spin and orbital currents in perpendicularly magnetized Pt/Co/Cu–CuOx systems. A maximum room temperature magnetoresistance of 0.38% was observed, exceeding the spin Hall magnetoresistance (SMR) of heavy metal-based heterostructures by one order of magnitude. The enhancement of magnetoresistance is attributed to the contributions from the OMR generated by the orbital Rashba effect at the Cu/CuOx interface and SMR induced by the spin Hall effect in heavy metal Pt. These results provide a pathway to understanding of the OAM transport in magnetic multilayer films and contribute to the design and realization of energy-efficient spin–orbitronic devices.
{"title":"Enhanced magnetoresistance induced collaboratively by spin and orbital currents","authors":"Shuyi Yang, Jinnan Liu, Huan Liu, Yongji Li, Wei Zhang, Zhongming Zeng, Zhiyong Quan","doi":"10.1063/5.0231164","DOIUrl":"https://doi.org/10.1063/5.0231164","url":null,"abstract":"Orbital currents in light metals or metal oxides without the strong spin–orbit coupling have become an important means to achieve low-power magnetization switching in spin–orbitronic devices. The orbital magnetoresistance (OMR) originated from orbital current represents a useful strategy to explore the interaction between the orbital angular momentum (OAM) and the local magnetic moment. However, systematic research works on the enhancement of OMR and the mechanism of OAM transport are seldom reported. In this study, we report a synergistically enhanced magnetoresistance effect induced by spin and orbital currents in perpendicularly magnetized Pt/Co/Cu–CuOx systems. A maximum room temperature magnetoresistance of 0.38% was observed, exceeding the spin Hall magnetoresistance (SMR) of heavy metal-based heterostructures by one order of magnitude. The enhancement of magnetoresistance is attributed to the contributions from the OMR generated by the orbital Rashba effect at the Cu/CuOx interface and SMR induced by the spin Hall effect in heavy metal Pt. These results provide a pathway to understanding of the OAM transport in magnetic multilayer films and contribute to the design and realization of energy-efficient spin–orbitronic devices.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"12 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224284","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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