Thermal effects represent a major challenge for all semiconductor devices, particularly high-power transistors such as GaN High Electron Mobility Transistors (HEMTs). The combined internal and external temperatures have a significant impact on the small and large signal characteristics of the device, degrading its performance. In this paper, a 10 × 200-µm GaN on Si substrate HEMT is characterized using small-signal S-parameter measurement setups at different ambient temperatures. The measurements are used to analyze the impact of temperature on the capacitances, inductances, and resistances of the transistor, as well as the gain and input/output reflection coefficients. Direct characterization of the gain shows a 3 dB reduction when the temperature increased by 100 °C. The results of the characterization are used to build a temperature-dependent model for the investigated device. The model's accuracy is validated through S-parameter simulation at different bias conditions and ambient temperatures. Additionally, the model's scalability has been demonstrated by modeling other GaN-on-Si HEMTs of different sizes. Excellent results and very good agreement between the simulations and measurements are achieved. The results of this investigation highlight the importance of thermal effects and the crucial need for efficient electrothermal modeling in designing reliable application circuits.
{"title":"A Comprehensive Investigation on Temperature-Dependent Small-Signal Characterization and Modeling of GaN HEMT on Si Substrate","authors":"Anwar Jarndal","doi":"10.1002/adts.202401555","DOIUrl":"https://doi.org/10.1002/adts.202401555","url":null,"abstract":"Thermal effects represent a major challenge for all semiconductor devices, particularly high-power transistors such as GaN High Electron Mobility Transistors (HEMTs). The combined internal and external temperatures have a significant impact on the small and large signal characteristics of the device, degrading its performance. In this paper, a 10 × 200-µm GaN on Si substrate HEMT is characterized using small-signal S-parameter measurement setups at different ambient temperatures. The measurements are used to analyze the impact of temperature on the capacitances, inductances, and resistances of the transistor, as well as the gain and input/output reflection coefficients. Direct characterization of the gain shows a 3 dB reduction when the temperature increased by 100 °C. The results of the characterization are used to build a temperature-dependent model for the investigated device. The model's accuracy is validated through S-parameter simulation at different bias conditions and ambient temperatures. Additionally, the model's scalability has been demonstrated by modeling other GaN-on-Si HEMTs of different sizes. Excellent results and very good agreement between the simulations and measurements are achieved. The results of this investigation highlight the importance of thermal effects and the crucial need for efficient electrothermal modeling in designing reliable application circuits.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"12 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143539321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The influence of alloying elements (Nb, Cr, V, Cu) on the mechanical properties of <span data-altimg="/cms/asset/43994b3b-8fb0-472b-afeb-f6c7202b5825/adts202401341-math-0003.png"></span><mjx-container ctxtmenu_counter="5" ctxtmenu_oldtabindex="1" jax="CHTML" role="application" sre-explorer- style="font-size: 103%; position: relative;" tabindex="0"><mjx-math aria-hidden="true" location="graphic/adts202401341-math-0003.png"><mjx-semantics><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-role="greekletter" data-semantic-speech="gamma" data-semantic-type="identifier"><mjx-c></mjx-c></mjx-mi></mjx-semantics></mjx-math><mjx-assistive-mml display="inline" unselectable="on"><math altimg="urn:x-wiley:25130390:media:adts202401341:adts202401341-math-0003" display="inline" location="graphic/adts202401341-math-0003.png" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mi data-semantic-="" data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic-role="greekletter" data-semantic-speech="gamma" data-semantic-type="identifier">γ</mi>$gamma$</annotation></semantics></math></mjx-assistive-mml></mjx-container>-TiAl alloys is investigated using first-principles calculations. The cluster expansion method is employed to determine the ground state configurations of the alloyed systems. The resulting formation energies are used to construct energy diagram. The analysis reveals that the formation energy is generally lower when alloying elements occupy the Ti sublattice. Elastic stiffness tensors are computed by applying small strains to the ground state structures, and the elastic constants are derived by averaging the values obtained from the Voigt model and the Reuss model. Further, the elastic moduli, Young's modulus, bulk modulus, and shear modulus demonstrate an increasing trend with alloying concentration, indicating enhanced material stiffness. The fracture toughness <span data-altimg="/cms/asset/af9eac74-6595-4f0b-8121-17853a9f4320/adts202401341-math-0004.png"></span><mjx-container ctxtmenu_counter="6" ctxtmenu_oldtabindex="1" jax="CHTML" role="application" sre-explorer- style="font-size: 103%; position: relative;" tabindex="0"><mjx-math aria-hidden="true" location="graphic/adts202401341-math-0004.png"><mjx-semantics><mjx-msub data-semantic-children="0,4" data-semantic- data-semantic-role="latinletter" data-semantic-speech="upper K Subscript upper I upper C" data-semantic-type="subscript"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="5" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c></mjx-c></mjx-mi><mjx-script style="vertical-align: -0.15em; margin-left: -0.04em;"><mjx-mrow data-semantic-annotation="clearspeak:simple;clearspeak:unit" data-semantic-children="1,2" data-semantic-content="3" data-semantic- data-semantic-parent="5" data-semantic-role="implicit" data-semantic-ty
{"title":"Influence of Alloying Additions (Nb, Cr, V, Cu) on the Mechanical Behavior of γ-TiAl","authors":"Mahfooz Alam, Appala Naidu Gandi","doi":"10.1002/adts.202401341","DOIUrl":"https://doi.org/10.1002/adts.202401341","url":null,"abstract":"The influence of alloying elements (Nb, Cr, V, Cu) on the mechanical properties of <span data-altimg=\"/cms/asset/43994b3b-8fb0-472b-afeb-f6c7202b5825/adts202401341-math-0003.png\"></span><mjx-container ctxtmenu_counter=\"5\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/adts202401341-math-0003.png\"><mjx-semantics><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"greekletter\" data-semantic-speech=\"gamma\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi></mjx-semantics></mjx-math><mjx-assistive-mml display=\"inline\" unselectable=\"on\"><math altimg=\"urn:x-wiley:25130390:media:adts202401341:adts202401341-math-0003\" display=\"inline\" location=\"graphic/adts202401341-math-0003.png\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mi data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic-role=\"greekletter\" data-semantic-speech=\"gamma\" data-semantic-type=\"identifier\">γ</mi>$gamma$</annotation></semantics></math></mjx-assistive-mml></mjx-container>-TiAl alloys is investigated using first-principles calculations. The cluster expansion method is employed to determine the ground state configurations of the alloyed systems. The resulting formation energies are used to construct energy diagram. The analysis reveals that the formation energy is generally lower when alloying elements occupy the Ti sublattice. Elastic stiffness tensors are computed by applying small strains to the ground state structures, and the elastic constants are derived by averaging the values obtained from the Voigt model and the Reuss model. Further, the elastic moduli, Young's modulus, bulk modulus, and shear modulus demonstrate an increasing trend with alloying concentration, indicating enhanced material stiffness. The fracture toughness <span data-altimg=\"/cms/asset/af9eac74-6595-4f0b-8121-17853a9f4320/adts202401341-math-0004.png\"></span><mjx-container ctxtmenu_counter=\"6\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/adts202401341-math-0004.png\"><mjx-semantics><mjx-msub data-semantic-children=\"0,4\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"upper K Subscript upper I upper C\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"5\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em; margin-left: -0.04em;\"><mjx-mrow data-semantic-annotation=\"clearspeak:simple;clearspeak:unit\" data-semantic-children=\"1,2\" data-semantic-content=\"3\" data-semantic- data-semantic-parent=\"5\" data-semantic-role=\"implicit\" data-semantic-ty","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"35 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143539305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermally activated delayed fluorescence (TADF) emitters are pivotal in enhancing the electroluminescence efficiency of organic light-emitting diodes (OLEDs) by enabling effective utilization of triplet excitons. Emitters based on naphthalimide (NI) have not received much attention, particularly the C3 substituted variants. In this study, a potential TADF molecule NI-AZB featuring 10-mesityl-5,10-dihydrodibenzo[b,e][1,4]azaborinine (AZB) as a donor is shortlisted after a rigorous consideration of several similar derivatives possessing donors such as carbazole, dimethylacridine, phenoxazine, and phenothiazine. Computational analyses indicate that NI-AZB exhibits a small singlet-triplet energy gap, promising radiative decay rates, moderate spin-orbit coupling, and substantial reverse intersystem crossing (rISC) rates. The S1 state of NI-AZB is charge-transfer (CT) in nature, while the T1 state exhibits localized excitation (LE), facilitating enhanced spin-orbit coupling and rISC rates. Additionally, NI-AZB absorbs in the UV region, suggesting its potential as a blue-emitting material for OLED devices. Furthermore, it is observed that substitution at the C4 of the naphthalimide core enhances CT character, leading to higher rISC rates but reduced radiative rates. Conversely, substitution at the C3 diminishes CT character, resulting in increased radiative rates while maintaining moderate rISC rates. These insights underscore the importance of C3 substitution in optimizing TADF properties of naphthalimide-based emitters for OLED applications.
{"title":"C3 Substituted Naphthalimide Derivatives as Promising TADF Emitters: Effect of Donor Strength Revealed by Computational Studies","authors":"Chetan Saini, K. R. Justin Thomas","doi":"10.1002/adts.202401571","DOIUrl":"https://doi.org/10.1002/adts.202401571","url":null,"abstract":"Thermally activated delayed fluorescence (TADF) emitters are pivotal in enhancing the electroluminescence efficiency of organic light-emitting diodes (OLEDs) by enabling effective utilization of triplet excitons. Emitters based on naphthalimide (NI) have not received much attention, particularly the C3 substituted variants. In this study, a potential TADF molecule <b>NI-AZB</b> featuring 10-mesityl-5,10-dihydrodibenzo[b,e][1,4]azaborinine (AZB) as a donor is shortlisted after a rigorous consideration of several similar derivatives possessing donors such as carbazole, dimethylacridine, phenoxazine, and phenothiazine. Computational analyses indicate that <b>NI-AZB</b> exhibits a small singlet-triplet energy gap, promising radiative decay rates, moderate spin-orbit coupling, and substantial reverse intersystem crossing (rISC) rates. The S<sub>1</sub> state of <b>NI-AZB</b> is charge-transfer (CT) in nature, while the T<sub>1</sub> state exhibits localized excitation (LE), facilitating enhanced spin-orbit coupling and rISC rates. Additionally, <b>NI-AZB</b> absorbs in the UV region, suggesting its potential as a blue-emitting material for OLED devices. Furthermore, it is observed that substitution at the C4 of the naphthalimide core enhances CT character, leading to higher rISC rates but reduced radiative rates. Conversely, substitution at the C3 diminishes CT character, resulting in increased radiative rates while maintaining moderate rISC rates. These insights underscore the importance of C3 substitution in optimizing TADF properties of naphthalimide-based emitters for OLED applications.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"14 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143532683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The magnetoelectric (ME) effect in composites consisting of a piezopolymer matrix (PVDF or akin) filled with the ferrite particles possessing weak or zero magnetostriction (barium hexaferrite, BFO or akin) is considered. A theoretical model is proposed that takes into account the contribution of the mechanical stresses arising due to magnetic torques applied to the particles on the part of external field. The model composite film is constructed as a layer of adjoined identical representative cells each of which is made of the PVDF polymer surrounding a single-domain platelet ferrite particle; the calculations are performed by finite-element method. The piezoelectric response of the model film is analyzed to find its dependence on the orientation of the particles, their positions with respect to the film boundary, and the direction of piezoelectric anisotropy of the matrix. The estimations show that, even in the case of zero magnetostriction of the ferrite, such a film is able to display the ME-effect quite comparable with that of the conventional PVDF-composites where the ME-effect is driven solely by the magnetostriction of cobalt ferrite. This result points out a way to develop efficient polymer ME composites for low-frequency applications under minimal requirements to the magnetostrictive properties of the filler.
{"title":"Magnetoelectric Effect in Piezopolymer Composites with a Weakly-Magnetostrictive Filler: The Contribution of Torsional Stresses","authors":"Oleg V. Stolbov, Yuriy L. Raikher","doi":"10.1002/adts.202401318","DOIUrl":"https://doi.org/10.1002/adts.202401318","url":null,"abstract":"The magnetoelectric (ME) effect in composites consisting of a piezopolymer matrix (PVDF or akin) filled with the ferrite particles possessing weak or zero magnetostriction (barium hexaferrite, BFO or akin) is considered. A theoretical model is proposed that takes into account the contribution of the mechanical stresses arising due to magnetic torques applied to the particles on the part of external field. The model composite film is constructed as a layer of adjoined identical representative cells each of which is made of the PVDF polymer surrounding a single-domain platelet ferrite particle; the calculations are performed by finite-element method. The piezoelectric response of the model film is analyzed to find its dependence on the orientation of the particles, their positions with respect to the film boundary, and the direction of piezoelectric anisotropy of the matrix. The estimations show that, even in the case of zero magnetostriction of the ferrite, such a film is able to display the ME-effect quite comparable with that of the conventional PVDF-composites where the ME-effect is driven solely by the magnetostriction of cobalt ferrite. This result points out a way to develop efficient polymer ME composites for low-frequency applications under minimal requirements to the magnetostrictive properties of the filler.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"84 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Previous works have demonstrated that complex soft robots can be built from simple building blocks, as evidenced by studies using no more than four primitive units to develop locomoting robots. However, these studies were restricted to idealized, non-physical deformations in physics engines lacking real-world actuation like pneumatic actuation. This study addresses this gap by utilizing non-linear finite element simulations and a custom Moore neighborhood encoding to model the deformation of primitive units for pneumatic actuation. A neural network meta-model is trained on a large dataset of automated simulations, allowing efficient soft robot design. The efficacy of the encoding and meta-model is demonstrated through the design of a pneumatically actuated asymmetric bending actuator. This design, though surprisingly different from conventional actuators, demonstrates high effectiveness. The meta-model's computational efficiency enables five optimization restarts in under 3% of the time required for a single finite element simulation, highlighting the encoding's ability to efficiently explore the design space and create high-performance soft robots.
{"title":"A Meta-Model for The Design of Soft Pneumatic Actuators Using Neural Networks and Finite Element Analysis","authors":"Philip Frederik Ligthart, Martin Philip Venter","doi":"10.1002/adts.202401014","DOIUrl":"https://doi.org/10.1002/adts.202401014","url":null,"abstract":"Previous works have demonstrated that complex soft robots can be built from simple building blocks, as evidenced by studies using no more than four primitive units to develop locomoting robots. However, these studies were restricted to idealized, non-physical deformations in physics engines lacking real-world actuation like pneumatic actuation. This study addresses this gap by utilizing non-linear finite element simulations and a custom Moore neighborhood encoding to model the deformation of primitive units for pneumatic actuation. A neural network meta-model is trained on a large dataset of automated simulations, allowing efficient soft robot design. The efficacy of the encoding and meta-model is demonstrated through the design of a pneumatically actuated asymmetric bending actuator. This design, though surprisingly different from conventional actuators, demonstrates high effectiveness. The meta-model's computational efficiency enables five optimization restarts in under 3% of the time required for a single finite element simulation, highlighting the encoding's ability to efficiently explore the design space and create high-performance soft robots.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"26 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Crystal growth, particularly silicon, is pivotal in the semiconductor industry. It serves as the foundation for electronic devices, solar cells, and various advanced technologies. The Czochralski method is a prominent technique for producing large single silicon crystals, well-known for its complexity due to the precise control required over temperature gradients, interface dynamics, and impurity incorporation— all critical factors for growing uniform, high-quality crystals. This paper proposes a hybrid SyMO (Symbolic regression Multi-objective Optimization) framework that combines Computational Fluid Dynamics (CFD), machine learning, and mathematical optimization techniques to investigate the effects of various process parameters, furnace geometries, and radiation shield material properties on key crystal quality metrics. The data set created from axisymmetric CFD simulations is used to fit symbolic regression models to effectively capture complex nonlinear relationships, ensuring accurate interface deflection and <span data-altimg="/cms/asset/4eed29dd-6738-4617-be70-15c197624b75/adts202401361-math-0001.png"></span><mjx-container ctxtmenu_counter="244" ctxtmenu_oldtabindex="1" jax="CHTML" role="application" sre-explorer- style="font-size: 103%; position: relative;" tabindex="0"><mjx-math aria-hidden="true" location="graphic/adts202401361-math-0001.png"><mjx-semantics><mjx-mrow data-semantic-children="0,2" data-semantic-content="1" data-semantic- data-semantic-role="division" data-semantic-speech="v divided by upper G" data-semantic-type="infixop"><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="3" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c></mjx-c></mjx-mi><mjx-mo data-semantic- data-semantic-operator="infixop,/" data-semantic-parent="3" data-semantic-role="division" data-semantic-type="operator" rspace="1" space="1"><mjx-c></mjx-c></mjx-mo><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic- data-semantic-parent="3" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c></mjx-c></mjx-mi></mjx-mrow></mjx-semantics></mjx-math><mjx-assistive-mml display="inline" unselectable="on"><math altimg="urn:x-wiley:25130390:media:adts202401361:adts202401361-math-0001" display="inline" location="graphic/adts202401361-math-0001.png" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow data-semantic-="" data-semantic-children="0,2" data-semantic-content="1" data-semantic-role="division" data-semantic-speech="v divided by upper G" data-semantic-type="infixop"><mi data-semantic-="" data-semantic-annotation="clearspeak:simple" data-semantic-font="italic" data-semantic-parent="3" data-semantic-role="latinletter" data-semantic-type="identifier">v</mi><mo data-semantic-="" data-semantic-operator="infixop,/" data-semantic-parent="3" data-semantic-role="division" data-semantic-type="operator">/</mo><mi dat
{"title":"SyMO: A Hybrid Approach for Multi-Objective Optimization of Crystal Growth Processes","authors":"Milena Petkovic, Natasha Dropka","doi":"10.1002/adts.202401361","DOIUrl":"https://doi.org/10.1002/adts.202401361","url":null,"abstract":"Crystal growth, particularly silicon, is pivotal in the semiconductor industry. It serves as the foundation for electronic devices, solar cells, and various advanced technologies. The Czochralski method is a prominent technique for producing large single silicon crystals, well-known for its complexity due to the precise control required over temperature gradients, interface dynamics, and impurity incorporation— all critical factors for growing uniform, high-quality crystals. This paper proposes a hybrid SyMO (Symbolic regression Multi-objective Optimization) framework that combines Computational Fluid Dynamics (CFD), machine learning, and mathematical optimization techniques to investigate the effects of various process parameters, furnace geometries, and radiation shield material properties on key crystal quality metrics. The data set created from axisymmetric CFD simulations is used to fit symbolic regression models to effectively capture complex nonlinear relationships, ensuring accurate interface deflection and <span data-altimg=\"/cms/asset/4eed29dd-6738-4617-be70-15c197624b75/adts202401361-math-0001.png\"></span><mjx-container ctxtmenu_counter=\"244\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/adts202401361-math-0001.png\"><mjx-semantics><mjx-mrow data-semantic-children=\"0,2\" data-semantic-content=\"1\" data-semantic- data-semantic-role=\"division\" data-semantic-speech=\"v divided by upper G\" data-semantic-type=\"infixop\"><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"3\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi><mjx-mo data-semantic- data-semantic-operator=\"infixop,/\" data-semantic-parent=\"3\" data-semantic-role=\"division\" data-semantic-type=\"operator\" rspace=\"1\" space=\"1\"><mjx-c></mjx-c></mjx-mo><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"3\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c></mjx-c></mjx-mi></mjx-mrow></mjx-semantics></mjx-math><mjx-assistive-mml display=\"inline\" unselectable=\"on\"><math altimg=\"urn:x-wiley:25130390:media:adts202401361:adts202401361-math-0001\" display=\"inline\" location=\"graphic/adts202401361-math-0001.png\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow data-semantic-=\"\" data-semantic-children=\"0,2\" data-semantic-content=\"1\" data-semantic-role=\"division\" data-semantic-speech=\"v divided by upper G\" data-semantic-type=\"infixop\"><mi data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic-parent=\"3\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\">v</mi><mo data-semantic-=\"\" data-semantic-operator=\"infixop,/\" data-semantic-parent=\"3\" data-semantic-role=\"division\" data-semantic-type=\"operator\">/</mo><mi dat","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"15 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ahmed H. Ati, Jiewei Cheng, Peng-Hu Du, Mohammed M. Obeid, Qiang Sun
Hydrogen fuel with zero CO2 emission is of current interest for global carbon neutralization. In this study, a 3D porous aluminum nitride (p-AlN) framework assemble from AlN-biphenylene nanoribbons and investigate its performance in reversible hydrogen storage is presented. Using density functional theory (DFT), it is showed that the p-AlN is dynamically and thermally stable, and exhibiting a semiconductor nature with a bandgap of 3.57 eV. The adsorption energy of H2 is in the range of −0.104 to −0.087 eV/H₂. According to ab initio molecular dynamics (AIMD) simulations, the H2 molecules remain stable above liquid nitrogen temperature (77 K). The studied system offers gravimetric (volumetric) capacities of 4.95 wt.% (67.86 g L−1) at 77 K/35 bar, and 1.41 wt.% (18.71 g L−1) at 298 K/100 bar, as revealed by grand canonical Monte Carlo (GCMC) simulations based on force field parameters fitted from DFT results.
{"title":"Computational Design of 3D Porous Aluminum Nitride Assembled From AlN-Biphenylene Nanoribbons for Reversible Hydrogen Storage","authors":"Ahmed H. Ati, Jiewei Cheng, Peng-Hu Du, Mohammed M. Obeid, Qiang Sun","doi":"10.1002/adts.202401402","DOIUrl":"https://doi.org/10.1002/adts.202401402","url":null,"abstract":"Hydrogen fuel with zero CO<sub>2</sub> emission is of current interest for global carbon neutralization. In this study, a 3D porous aluminum nitride (<i>p</i>-AlN) framework assemble from AlN-biphenylene nanoribbons and investigate its performance in reversible hydrogen storage is presented. Using density functional theory (DFT), it is showed that the <i>p</i>-AlN is dynamically and thermally stable, and exhibiting a semiconductor nature with a bandgap of 3.57 eV. The adsorption energy of H<sub>2</sub> is in the range of −0.104 to −0.087 eV/H₂. According to ab initio molecular dynamics (AIMD) simulations, the H<sub>2</sub> molecules remain stable above liquid nitrogen temperature (77 K). The studied system offers gravimetric (volumetric) capacities of 4.95 wt.% (67.86 g L<sup>−1</sup>) at 77 K/35 bar, and 1.41 wt.% (18.71 g L<sup>−1</sup>) at 298 K/100 bar, as revealed by grand canonical Monte Carlo (GCMC) simulations based on force field parameters fitted from DFT results.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"16 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An innovative method is introduced to improve oil recovery techniques by combining Artificial Neural Networks with Proportional-Integral-Derivative control systems. Acknowledging the significant progress in artificial intelligence, the study primarily focuses on employing Artificial Neural Networks to model the steam injection of alumina nanoparticles into a 2D porous medium, simulating steam injection-enhanced oil Recovery scenarios. The data from numerical simulations and the Levenberg-Marquardt backpropagation algorithm are used to train nine distinct neural networks using MATLAB neural network fitting, achieving an impressive mean squared error <0.001 at optimal performance. The general simulation structure features a dual neural network system, where one network simulates the recovery process and receives stable input values to generate a variable reference recovery factor for the controller. This setup utilizes feedback from the process-representing neural network to produce a control signal, enabling real-time adjustments to the neural network inputs for optimizing the recovery factor. The study investigates both open-loop and closed-loop responses to disturbances, demonstrating that while controlling nanoparticle concentration and temperature does not effectively maintain the desired recovery factor, adjusting the injection velocity through the control scheme successfully mitigated disturbances. This approach ensures precise reference tracking, achieving an average mean squared error <0.002.
{"title":"A Dual Neural Network Approach with PID Control and Reference Tracking to Enhance Oil Recovery","authors":"Keyvan Ahangar Darabi, Majid Ahmadlouydarab","doi":"10.1002/adts.202401168","DOIUrl":"https://doi.org/10.1002/adts.202401168","url":null,"abstract":"An innovative method is introduced to improve oil recovery techniques by combining Artificial Neural Networks with Proportional-Integral-Derivative control systems. Acknowledging the significant progress in artificial intelligence, the study primarily focuses on employing Artificial Neural Networks to model the steam injection of alumina nanoparticles into a 2D porous medium, simulating steam injection-enhanced oil Recovery scenarios. The data from numerical simulations and the Levenberg-Marquardt backpropagation algorithm are used to train nine distinct neural networks using MATLAB neural network fitting, achieving an impressive mean squared error <0.001 at optimal performance. The general simulation structure features a dual neural network system, where one network simulates the recovery process and receives stable input values to generate a variable reference recovery factor for the controller. This setup utilizes feedback from the process-representing neural network to produce a control signal, enabling real-time adjustments to the neural network inputs for optimizing the recovery factor. The study investigates both open-loop and closed-loop responses to disturbances, demonstrating that while controlling nanoparticle concentration and temperature does not effectively maintain the desired recovery factor, adjusting the injection velocity through the control scheme successfully mitigated disturbances. This approach ensures precise reference tracking, achieving an average mean squared error <0.002.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"49 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yanyan Zhang, Yinghao Wang, Jie Shen, Dongliang Zhang, Zhiwen Gan, Bo Yang, Zhiyin Gan, Fan Wang
Although single-crystal diamond is successfully grown on some other substrate materials, the heteroepitaxial mechanism is still not fully understood. In this research, by analyzing the density of states curve of surface atoms in heterostructures and comparing them with atoms in the bulk material, the electronic properties of the surface atoms can be revealed. Monolayer carbon (C) atoms on cubic boron nitride (c-BN) surface exhibit some properties of diamond-like carbon. Conversely, the monolayer C atoms covering the Iridium (Ir) surface demonstrate distinct metallic properties. The C atoms on the surface of the 8-layer heterostructure exhibit some properties of diamond-like carbon. This explains why single-crystal diamond heteroepitaxy growth on Ir film requires the bias-enhanced nucleation process. However, on the c-BN surface, single-crystal diamonds can be grown directly. The method is also used to analyze the heteroepitaxy of indium phosphide (InP) on gallium arsenide (GaAs) and gallium nitride (GaN) on aluminum nitride (AlN), and the results have further confirmed the effectiveness. Therefore, this approach offers a new perspective for identifying suitable substrate materials based on their electronic properties, rather than solely relying on the matching of lattice constants and surface energies.
{"title":"Research on the Mechanism of Diamond Heteroepitaxial Growth Based on First-principles Calculations","authors":"Yanyan Zhang, Yinghao Wang, Jie Shen, Dongliang Zhang, Zhiwen Gan, Bo Yang, Zhiyin Gan, Fan Wang","doi":"10.1002/adts.202500070","DOIUrl":"https://doi.org/10.1002/adts.202500070","url":null,"abstract":"Although single-crystal diamond is successfully grown on some other substrate materials, the heteroepitaxial mechanism is still not fully understood. In this research, by analyzing the density of states curve of surface atoms in heterostructures and comparing them with atoms in the bulk material, the electronic properties of the surface atoms can be revealed. Monolayer carbon (C) atoms on cubic boron nitride (c-BN) surface exhibit some properties of diamond-like carbon. Conversely, the monolayer C atoms covering the Iridium (Ir) surface demonstrate distinct metallic properties. The C atoms on the surface of the 8-layer heterostructure exhibit some properties of diamond-like carbon. This explains why single-crystal diamond heteroepitaxy growth on Ir film requires the bias-enhanced nucleation process. However, on the c-BN surface, single-crystal diamonds can be grown directly. The method is also used to analyze the heteroepitaxy of indium phosphide (InP) on gallium arsenide (GaAs) and gallium nitride (GaN) on aluminum nitride (AlN), and the results have further confirmed the effectiveness. Therefore, this approach offers a new perspective for identifying suitable substrate materials based on their electronic properties, rather than solely relying on the matching of lattice constants and surface energies.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"51 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143485892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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