Sadia Irshad, Shah Jahan, Afraz Hussain Majeed, Ehab Ghith, Mehdi Tlija, Atif Asghar, Nusrat Rehman
The objective of this research endeavor is to examine the properties of stagnation point flow in the presence of absorption, viscous dissipation, and internal thermal generation with respect to a shrinking surface. The resulting system of differential equations is notoriously challenging to solve analytically. The equations controlling the boundary layer flow were solved using a finite difference method. The analysis includes the examination of important physical quantities through the presentation of plots and tabulated values. Our findings reveal a strong connection between the presence of solutions for high shrinking parameters and the magnetic field that was applied. Temperatures increase when there is an increase in both Ec and α at the same time. These results also suggest a shallowing of the thermal boundary layer. As a result of these findings, it appears that temperature and thermal boundary layer thickness are sensitive to changes in these factors.
{"title":"Numerical investigation of stagnation point heat transfer with MHD effects using finite difference method: Analysis of thermal absorption and generation","authors":"Sadia Irshad, Shah Jahan, Afraz Hussain Majeed, Ehab Ghith, Mehdi Tlija, Atif Asghar, Nusrat Rehman","doi":"10.1063/5.0219843","DOIUrl":"https://doi.org/10.1063/5.0219843","url":null,"abstract":"The objective of this research endeavor is to examine the properties of stagnation point flow in the presence of absorption, viscous dissipation, and internal thermal generation with respect to a shrinking surface. The resulting system of differential equations is notoriously challenging to solve analytically. The equations controlling the boundary layer flow were solved using a finite difference method. The analysis includes the examination of important physical quantities through the presentation of plots and tabulated values. Our findings reveal a strong connection between the presence of solutions for high shrinking parameters and the magnetic field that was applied. Temperatures increase when there is an increase in both Ec and α at the same time. These results also suggest a shallowing of the thermal boundary layer. As a result of these findings, it appears that temperature and thermal boundary layer thickness are sensitive to changes in these factors.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"27 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224292","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}
With the increasing integration levels of modern electronic products, effective thermal management has become a critical concern to ensure the operational efficiency and longevity of electronic devices. Developing thermal interface materials that possess both high thermal conductivity (κ) and reliable insulation properties has presented a significant challenge. In this study, boron nitride fibers (BNF) with a substantial length-to-diameter ratio were fabricated to serve as vertically aligned thermal conduction channels within a composite pad containing a silicone gel matrix.Under typical packing pressure conditions, the resulting BNF pad exhibits an exceptionally high through-plane thermal conductivity (40 vol. %: κ⊥ = 16.77 W/mK). Additionally, the BNF pad demonstrates favorable mechanical and dielectric properties, enhancing its versatility and applicability. The results of actual heat dissipation tests further validate the excellent thermal management capabilities of these composites in high-power electronic applications.
{"title":"Electrically insulating thermal interface material with ultrahigh thermal conductivity enabled by vertical boron nitride fibers","authors":"Haoran Yang, Yisimayili Tuersun, Pingjun Luo, Yixin Chen, Xu Huang, Qi Huang, Xuechen Chen, Sheng Chu","doi":"10.1063/5.0207569","DOIUrl":"https://doi.org/10.1063/5.0207569","url":null,"abstract":"With the increasing integration levels of modern electronic products, effective thermal management has become a critical concern to ensure the operational efficiency and longevity of electronic devices. Developing thermal interface materials that possess both high thermal conductivity (κ) and reliable insulation properties has presented a significant challenge. In this study, boron nitride fibers (BNF) with a substantial length-to-diameter ratio were fabricated to serve as vertically aligned thermal conduction channels within a composite pad containing a silicone gel matrix.Under typical packing pressure conditions, the resulting BNF pad exhibits an exceptionally high through-plane thermal conductivity (40 vol. %: κ⊥ = 16.77 W/mK). Additionally, the BNF pad demonstrates favorable mechanical and dielectric properties, enhancing its versatility and applicability. The results of actual heat dissipation tests further validate the excellent thermal management capabilities of these composites in high-power electronic applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"60 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224294","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}
Background: Lung cancer is a major health concern globally, being the primary cause of cancer-related deaths. It accounts for approximately one–sixth of all cancer fatalities. Objective: The goal of this study is to develop an effective method for the early detection of lung tumors using computed tomography (CT) images. This method aims to identify lung tumors of various sizes and shapes, which is a significant challenge due to the variability in tumor characteristics. Methods: The research utilizes CT images of the lungs in sagittal view from the LID-IDRI database. To tackle the issue of tumor variability in size, shape, and number, the study proposes a novel image processing technique. This technique involves detecting tumor clusters using a weighted average-based automatic thresholding method. This method focuses on maximizing inter-class variance and is supplemented by further classification and segmentation processes. Results: The proposed image processing technique was tested on a dataset of 315 lung CT images. It demonstrated a high level of accuracy, achieving a 98.96% success rate in identifying lung tumors. Conclusion: The study introduces a highly effective method for the detection of lung tumors in CT images, irrespective of their size and shape. The technique’s high accuracy rate suggests it could be a valuable tool in the early diagnosis of lung cancer, potentially leading to improved patient outcomes.
{"title":"Segmentation of lung nodules in CT images using weighted average based threshold and maximized variance","authors":"Yankun Liu, Tong Zhang, Ma Liang, Enguo Wang","doi":"10.1063/5.0216374","DOIUrl":"https://doi.org/10.1063/5.0216374","url":null,"abstract":"Background: Lung cancer is a major health concern globally, being the primary cause of cancer-related deaths. It accounts for approximately one–sixth of all cancer fatalities. Objective: The goal of this study is to develop an effective method for the early detection of lung tumors using computed tomography (CT) images. This method aims to identify lung tumors of various sizes and shapes, which is a significant challenge due to the variability in tumor characteristics. Methods: The research utilizes CT images of the lungs in sagittal view from the LID-IDRI database. To tackle the issue of tumor variability in size, shape, and number, the study proposes a novel image processing technique. This technique involves detecting tumor clusters using a weighted average-based automatic thresholding method. This method focuses on maximizing inter-class variance and is supplemented by further classification and segmentation processes. Results: The proposed image processing technique was tested on a dataset of 315 lung CT images. It demonstrated a high level of accuracy, achieving a 98.96% success rate in identifying lung tumors. Conclusion: The study introduces a highly effective method for the detection of lung tumors in CT images, irrespective of their size and shape. The technique’s high accuracy rate suggests it could be a valuable tool in the early diagnosis of lung cancer, potentially leading to improved patient outcomes.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"8 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185417","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}
Xin Huang, Wenhao Zhao, Meisong Yuan, Kaixuan Sun, Bo Yang
Insect-electronics hybrid robots integrate live insects with small electronic backpacks. These backpacks guide insect movement and sense environmental data. Due to size and payload constraints, high-capacity batteries are impractical for prolonged energy supply. This study proposes a self-sustaining wireless sensing and flight control device with an energy management module and a Bluetooth slave module. This setup enables solar energy harvesting, wireless flight control of beetles, and the acquisition of image and attitude information. The device achieves directional flight control with a 72.5% success rate in turning. Operation duration increases by 46.6% in image-only mode and 50.9% in combined image and attitude angle mode under 20 000 lux indoor illuminance. Outdoor experiments demonstrate continuous operation at one image per second under favorable illuminance conditions, with a 92% increase in operation time when capturing images and yaw angles. This microelectronic device enhances the durability of insect robots during extended field missions, providing valuable insights into long-term environmental monitoring.
{"title":"A self-sustaining wireless sensing and flight control device for beetles","authors":"Xin Huang, Wenhao Zhao, Meisong Yuan, Kaixuan Sun, Bo Yang","doi":"10.1063/5.0228102","DOIUrl":"https://doi.org/10.1063/5.0228102","url":null,"abstract":"Insect-electronics hybrid robots integrate live insects with small electronic backpacks. These backpacks guide insect movement and sense environmental data. Due to size and payload constraints, high-capacity batteries are impractical for prolonged energy supply. This study proposes a self-sustaining wireless sensing and flight control device with an energy management module and a Bluetooth slave module. This setup enables solar energy harvesting, wireless flight control of beetles, and the acquisition of image and attitude information. The device achieves directional flight control with a 72.5% success rate in turning. Operation duration increases by 46.6% in image-only mode and 50.9% in combined image and attitude angle mode under 20 000 lux indoor illuminance. Outdoor experiments demonstrate continuous operation at one image per second under favorable illuminance conditions, with a 92% increase in operation time when capturing images and yaw angles. This microelectronic device enhances the durability of insect robots during extended field missions, providing valuable insights into long-term environmental monitoring.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"5 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185418","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}
J. M. Losada, A. D. Helgeland, J. L. Terry, O. E. Garcia
Time delay and velocity estimation methods have been widely studied subjects in the context of signal processing, with applications in many different fields of physics. The velocity of waves or coherent fluctuation structures is commonly estimated as the distance between two measurement points divided by the time lag that maximizes the cross correlation function between the measured signals, but this is demonstrated to result in erroneous estimates for two spatial dimensions. We present an improved method to accurately estimate both components of the velocity vector, relying on three non-aligned measurement points. We introduce a stochastic process describing the fluctuations as a superposition of uncorrelated pulses moving in two dimensions. Using this model, we show that the three-point velocity estimation method, using time delays calculated through cross correlations, yields the exact velocity components when all pulses have the same velocity. The two- and three-point methods are tested on synthetic data generated from realizations of such processes for which the underlying velocity components are known. The results reveal the superiority of the three-point technique. Finally, we demonstrate the applicability of the velocity estimation on gas puff imaging data of strongly intermittent plasma fluctuations due to the radial motion of coherent, blob-like structures at the boundary of the Alcator C-Mod tokamak.
{"title":"A three-point velocity estimation method for two-dimensional coarse-grained imaging data","authors":"J. M. Losada, A. D. Helgeland, J. L. Terry, O. E. Garcia","doi":"10.1063/5.0197251","DOIUrl":"https://doi.org/10.1063/5.0197251","url":null,"abstract":"Time delay and velocity estimation methods have been widely studied subjects in the context of signal processing, with applications in many different fields of physics. The velocity of waves or coherent fluctuation structures is commonly estimated as the distance between two measurement points divided by the time lag that maximizes the cross correlation function between the measured signals, but this is demonstrated to result in erroneous estimates for two spatial dimensions. We present an improved method to accurately estimate both components of the velocity vector, relying on three non-aligned measurement points. We introduce a stochastic process describing the fluctuations as a superposition of uncorrelated pulses moving in two dimensions. Using this model, we show that the three-point velocity estimation method, using time delays calculated through cross correlations, yields the exact velocity components when all pulses have the same velocity. The two- and three-point methods are tested on synthetic data generated from realizations of such processes for which the underlying velocity components are known. The results reveal the superiority of the three-point technique. Finally, we demonstrate the applicability of the velocity estimation on gas puff imaging data of strongly intermittent plasma fluctuations due to the radial motion of coherent, blob-like structures at the boundary of the Alcator C-Mod tokamak.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"13 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185419","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 integration of electric vehicles (EVs) is becoming vital for both the transportation and energy sectors. At the same time, they need an appropriate charging facility. Photovoltaic (PV) powered electric vehicle chargers are gaining popularity since they require negligible maintenance and steadily enhance the efficiency of PV modules. In this paper, a grid tied solar PV with a 12 pulse Line Commutated Converter (LCC) based off board EV charger is presented. The specialty of the proposed method is that it does not require an extra controller for ac grid synchronization. In addition, simplified maximum power point tracking (MPPT) control is proposed, which will track the MPP of the PV array. The main disadvantage of LCC is its poor harmonics profile, which can be improved by a higher pulse number with adequate phase shift. With 12 pulse LCC, high characteristics harmonics are greatly reduced. The performance and efficacy of the suggested method have been confirmed by simulation, which proves the feasibility of the proposed solution for EV charging in both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) modes.
{"title":"A grid tied solar photovoltaic based off board electric vehicle charger in G2V and V2G mode","authors":"Jyoti M. Kumbhare, Sumant G. Kadwane","doi":"10.1063/5.0212427","DOIUrl":"https://doi.org/10.1063/5.0212427","url":null,"abstract":"The integration of electric vehicles (EVs) is becoming vital for both the transportation and energy sectors. At the same time, they need an appropriate charging facility. Photovoltaic (PV) powered electric vehicle chargers are gaining popularity since they require negligible maintenance and steadily enhance the efficiency of PV modules. In this paper, a grid tied solar PV with a 12 pulse Line Commutated Converter (LCC) based off board EV charger is presented. The specialty of the proposed method is that it does not require an extra controller for ac grid synchronization. In addition, simplified maximum power point tracking (MPPT) control is proposed, which will track the MPP of the PV array. The main disadvantage of LCC is its poor harmonics profile, which can be improved by a higher pulse number with adequate phase shift. With 12 pulse LCC, high characteristics harmonics are greatly reduced. The performance and efficacy of the suggested method have been confirmed by simulation, which proves the feasibility of the proposed solution for EV charging in both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) modes.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"6 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224293","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}
Chao-Ching Chiang, Jian-Sian Li, Hsiao-Hsuan Wan, Fan Ren, Stephen J. Pearton
The use of the low work function (4.5 eV) tungsten (W) as a rectifying contact was studied to obtain low on-voltages in W/Ga2O3 Schottky rectifiers and NiO/Ga2O3 heterojunction rectifiers that were simultaneously fabricated on a single wafer. The devices were produced with varying proportions of relative areas and diameters, encompassing a spectrum from pure Schottky Barrier Diode (SBD) to pure Heterojunction Diode (HJD) configurations. The turn-on voltages with W contacts ranged from 0.22 V for pure Schottky rectifiers to 1.50 V for pure HJDs, compared to 0.66 and 1.77 V, respectively, for Ni/Au contacts. The reverse recovery times ranged from 31.2 to 33.5 ns for pure Schottky and heterojunction rectifiers. Switching energy losses for the SBD with W contacts were ∼20% of those for HJDs. The reverse breakdown voltages ranged from 600 V for SBDs to 2400 V for HJDs. These are the lowest reported turn-on voltage values for 600/1200 V-class Ga2O3 rectifiers that extend the range of applications of these devices down to the voltages of interest for electric vehicle charging applications.
研究人员利用低功函数（4.5 eV）钨（W）作为整流触点，在 W/Ga2O3 肖特基整流器和 NiO/Ga2O3 异质结整流器中获得低导通电压。这些器件的相对面积和直径比例各不相同，涵盖了从纯肖特基势垒二极管（SBD）到纯异质结二极管（HJD）的各种配置。纯肖特基整流器 W 触点的开启电压为 0.22 V，纯 HJD 为 1.50 V，而镍/金触点的开启电压分别为 0.66 V 和 1.77 V。纯肖特基和异质结整流器的反向恢复时间为 31.2 至 33.5 ns。带 W 触点的 SBD 的开关能量损失是 HJD 的 20%。SBD 的反向击穿电压从 600 V 到 HJD 的 2400 V 不等。这是报告的 600/1200 V 级 Ga2O3 整流器的最低导通电压值，将这些器件的应用范围扩展到了电动汽车充电应用所需的电压。
{"title":"Achievement of low turn-on voltage in Ga2O3 Schottky and heterojunction hybrid rectifiers using W/Au anode contact","authors":"Chao-Ching Chiang, Jian-Sian Li, Hsiao-Hsuan Wan, Fan Ren, Stephen J. Pearton","doi":"10.1063/5.0227210","DOIUrl":"https://doi.org/10.1063/5.0227210","url":null,"abstract":"The use of the low work function (4.5 eV) tungsten (W) as a rectifying contact was studied to obtain low on-voltages in W/Ga2O3 Schottky rectifiers and NiO/Ga2O3 heterojunction rectifiers that were simultaneously fabricated on a single wafer. The devices were produced with varying proportions of relative areas and diameters, encompassing a spectrum from pure Schottky Barrier Diode (SBD) to pure Heterojunction Diode (HJD) configurations. The turn-on voltages with W contacts ranged from 0.22 V for pure Schottky rectifiers to 1.50 V for pure HJDs, compared to 0.66 and 1.77 V, respectively, for Ni/Au contacts. The reverse recovery times ranged from 31.2 to 33.5 ns for pure Schottky and heterojunction rectifiers. Switching energy losses for the SBD with W contacts were ∼20% of those for HJDs. The reverse breakdown voltages ranged from 600 V for SBDs to 2400 V for HJDs. These are the lowest reported turn-on voltage values for 600/1200 V-class Ga2O3 rectifiers that extend the range of applications of these devices down to the voltages of interest for electric vehicle charging applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"9 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224297","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 work, the higher order electrostatic and solitonic EA energy plasma in auroral plasma has been investigated. The perturbed KdV form has been solved. The modulated soliton speed, energy of the cold beam electrons, and the associated higher fifth order electrostatic field have been mathematically derived. The effect of perturbed beam density as well as beam temperature parameters on the dressed electrostatic and energy properties has been discussed. The auroral plasma results in this work may be important in space applications.
本研究对极光等离子体中的高阶静电和孤子 EA 能量等离子体进行了研究。对扰动 KdV 形式进行了求解。调制孤子的速度、冷束电子的能量以及相关的高五阶静电场都已用数学方法推导出来。还讨论了扰动束密度和束流温度参数对敷装静电和能量特性的影响。这项工作中的极光等离子体结果可能在空间应用中具有重要意义。
{"title":"On the modulated fifth order dressed electron acoustic electrostatic and energy features in auroral plasma","authors":"K. S. Alsadi, E. M. Darwish, E. K. El-Shewy","doi":"10.1063/5.0227184","DOIUrl":"https://doi.org/10.1063/5.0227184","url":null,"abstract":"In this work, the higher order electrostatic and solitonic EA energy plasma in auroral plasma has been investigated. The perturbed KdV form has been solved. The modulated soliton speed, energy of the cold beam electrons, and the associated higher fifth order electrostatic field have been mathematically derived. The effect of perturbed beam density as well as beam temperature parameters on the dressed electrostatic and energy properties has been discussed. The auroral plasma results in this work may be important in space applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"22 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142185420","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}
Xiangjian Wang, Oleg. N. Antzutkin, J. Andreas Larsson
In this work, we investigate the ion pair tetramethylphosphonium cation, [P1,1,1,1]+, and bis(oxalato)borate anion, [BOB]−, as a model system for the study of ionic liquids interacting with both hydroxylated and oxygen terminated α-SiO2 (001) surfaces, using first-principles electronic structure theory. We use a single ionic pair and clusters of ion pairs, in order to have exclusively neutral supercell slab models. We use dispersion-corrected density functional theory (DFT) to ascertain that both the strong physical binding between the ions, dominated by ionic binding, and the weaker physical binding of ions to the different surfaces are correctly described. We have found that the binding of ion pairs is stronger to the hydroxylated α-SiO2 (001) surface compared to the oxygen terminated surface, which is attributed to the formation of H-binding with the oxygen atom(s) of the [BOB]− anion. Through rotation of ionic pair(s), we estimate the surface-ions energy barrier for translational movement and, thus, the strength of H-binding of the ions. At the surface of hydroxylated α-SiO2 (001), we have studied how water molecules form a network of H-binding with the OH groups of the surface and the [BOB]− anion, which offers an explanation for the reduction in the friction of ionic liquids on the inclusion of water. We suggest modeling protocols for simulation of ion pairs on surfaces, which can open up the possibility to use DFT to aid in designing and understanding the physicochemical mechanism of interactions of ionic materials (including ionic liquids) in various technological applications.
在这项研究中，我们利用第一原理电子结构理论研究了离子对四甲基鏻阳离子 [P1,1,1,1]+ 和双(草酸)硼酸阴离子 [BOB]-，并将其作为研究离子液体与羟基化和氧端化 α-SiO2 (001) 表面相互作用的模型系统。我们使用单个离子对和离子对簇，以建立完全中性的超胞板坯模型。我们使用色散校正密度泛函理论（DFT）来确定离子之间以离子结合为主的强物理结合以及离子与不同表面的弱物理结合都得到了正确的描述。我们发现，离子对与羟基化的α-SiO2 (001) 表面相比，与氧终止表面的结合力更强，这归因于[BOB]- 阴离子的氧原子形成了氢键结合。通过离子对的旋转，我们估算出了表面-离子平移运动的能量势垒，从而估算出了离子与 H 结合的强度。在羟基化的α-SiO2 (001) 表面，我们研究了水分子如何与表面的羟基和[BOB]-阴离子形成 H 结合网络，这为离子液体加入水后摩擦力减小提供了解释。我们提出了模拟表面离子对的建模协议，这为利用 DFT 帮助设计和理解各种技术应用中离子材料（包括离子液体）相互作用的物理化学机制提供了可能。
{"title":"Density functional theory study of physisorption of ionic liquid pairs on hydroxylated and oxygen terminated α-SiO2 (001) surfaces","authors":"Xiangjian Wang, Oleg. N. Antzutkin, J. Andreas Larsson","doi":"10.1063/5.0221708","DOIUrl":"https://doi.org/10.1063/5.0221708","url":null,"abstract":"In this work, we investigate the ion pair tetramethylphosphonium cation, [P1,1,1,1]+, and bis(oxalato)borate anion, [BOB]−, as a model system for the study of ionic liquids interacting with both hydroxylated and oxygen terminated α-SiO2 (001) surfaces, using first-principles electronic structure theory. We use a single ionic pair and clusters of ion pairs, in order to have exclusively neutral supercell slab models. We use dispersion-corrected density functional theory (DFT) to ascertain that both the strong physical binding between the ions, dominated by ionic binding, and the weaker physical binding of ions to the different surfaces are correctly described. We have found that the binding of ion pairs is stronger to the hydroxylated α-SiO2 (001) surface compared to the oxygen terminated surface, which is attributed to the formation of H-binding with the oxygen atom(s) of the [BOB]− anion. Through rotation of ionic pair(s), we estimate the surface-ions energy barrier for translational movement and, thus, the strength of H-binding of the ions. At the surface of hydroxylated α-SiO2 (001), we have studied how water molecules form a network of H-binding with the OH groups of the surface and the [BOB]− anion, which offers an explanation for the reduction in the friction of ionic liquids on the inclusion of water. We suggest modeling protocols for simulation of ion pairs on surfaces, which can open up the possibility to use DFT to aid in designing and understanding the physicochemical mechanism of interactions of ionic materials (including ionic liquids) in various technological applications.","PeriodicalId":7619,"journal":{"name":"AIP Advances","volume":"28 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224298","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}
S. R. Seyyedi Birjand, R. Sabbaghzadeh, Maliheh Azadparvar, H. A. Rahnamaye Aliabad
The biophysical properties of metoprolol are investigated by the full potential-linearized augmented plane wave method and molecular docking and molecular dynamic approaches. The exchange–correlation potentials are calculated by the Perdew–Burke–Ernzerhof generalized gradient approximation as implemented in the WIEN2k package. The electronic results show the insulator nature of metoprolol with the indirect bandgap of 3.74 eV between HOMO and LUMO states. In the density of state spectra, the p state of O, C, and N elements confirm the stability of metoprolol. Metoprolol exhibits a metallic behavior in the z direction, while it has a dielectric behavior in the x and y directions. The static refractive indices are obtained 1.49, 1.53, and 1.63 in the x, y, and z directions, respectively. It was found that the maximum reflectivity occurs at the ultraviolet region in the z-direction. The calculated absorption spectra also confirm the other’s experimental results. The obtained results of molecular docking indicate the formation of hydrogen bonds between metoprolol and the beta-2 adrenergic receptors, and molecular dynamics showed a human beta-2 adrenoceptor either in its free state or in complex with a metoprolol molecule. The calculated binding energies of elements by molecular docking and the other biological properties of metoprolol by molecular dynamic are in close agreement with obtained Density Functional Theory (DFT) results for Pharmacia applications.
采用全电位线性化增强平面波法以及分子对接和分子动力学方法研究了美托洛尔的生物物理特性。交换相关电势是通过 WIEN2k 软件包中实现的 Perdew-Burke-Ernzerhof 广义梯度近似法计算得出的。电子结果显示美托洛尔具有绝缘体性质，其 HOMO 和 LUMO 态之间的间接带隙为 3.74 eV。在状态密度谱图中，O、C 和 N 元素的 p 态证实了美托洛尔的稳定性。美托洛尔在 z 方向上表现出金属特性，而在 x 和 y 方向上则表现出介电特性。在 x、y 和 z 方向上的静态折射率分别为 1.49、1.53 和 1.63。研究发现，最大反射率出现在 z 方向的紫外线区域。计算得出的吸收光谱也证实了其他实验结果。分子对接结果表明，美托洛尔与 beta-2 肾上腺素能受体之间形成了氢键，分子动力学结果显示，人 beta-2 肾上腺素受体处于自由状态或与美托洛尔分子复合。通过分子对接计算出的元素结合能以及通过分子动力学计算出的美托洛尔的其他生物特性与在药典应用中获得的密度泛函理论（DFT）结果非常吻合。
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