Article
Materials Science, Ceramics
Yu-Sheng Tsai, Jyun-Rong Chen, Chang-Hsueh Lee, Chih-Chen Kuo, Ya-Hsuan Lin, Chun-Chieh Wang, Yu-Cheng Chang, YewChung Sermon Wu, Hsiang Chen
Summary: In this study, different types of ZnO-based nanocomposites were fabricated and characterized. The etching of ZnO nanorods increased the surface area and defect concentration, while sulfurization of the ZnO/ZnS nanotubes reduced defects and improved surface roughness. The results indicate that ZnO and ZnO/ZnS nanotubes hold promise for sensing device applications.
CERAMICS INTERNATIONAL
(2022)
Article
Chemistry, Multidisciplinary
Nehal Ali, El-Refaie Kenawy, A. A. Wadoud, M. I. Elhadary
Summary: This work utilized new functional high-performance piezoelectric materials to achieve sustainable energy production in wearable self-powered electrical devices. Highly aligned nanofibers were produced using an innovative modification in electrospinning. Flexible membrane constituents were combined to create a novel composite nanofiber mat, which improved the piezoelectric properties while maintaining flexibility. The nanofiber mat, inserted between thermoplastic sheets with conductive electrodes, shows superior performance and provides a simple, efficient, and cost-effective solution for microelectronic wearable devices.
Article
Physics, Applied
C. A. Figueroa, M. C. Zapata, G. Bridoux, J. Ferreyra, L. Patrone, L. Malatto, J. Guimpel, G. Nieva, V Runco Leal, C. Navarro, M. Villafuerte
Summary: The work reported on the fabrication and characterization of a field effect transistor based on a ZnO/MgO bilayer with a top-gate configuration. X-ray diffraction patterns showed epitaxial growth of ZnO and MgO films. The intrinsic properties of transparent conducting oxides were shown to determine key parameters of a FET device.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Thuy T. D. Nguyen, Dung Van Dao, Dong-Seog Kim, Hu-Jun Lee, Sang-Yeob Oh, In-Hwan Lee, Yeon-Tae Yu
Summary: A versatile hydrogen gas sensor was fabricated using Pd@ZnO core-shell nanoparticles synthesized through a hydrothermal route. The optimal sensor, Pd@ZnO-2, demonstrated superior performance compared to Pd@ZnO-1 and pure ZnO, with higher response, faster response and recovery times to 100 ppm hydrogen at 350 degrees C. The high selectivity of Pd@ZnO-2 sensor to hydrogen can be attributed to the higher metallic Pd content remaining in the sample after calcination in argon.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Inorganic & Nuclear
Lei Zhang, Baoyan Liang, He Zhao, Jiabin Yang, Mingshuai Jiao, Yunlong Liu
Summary: A core-shell structure homogeneous junction ZnO photocatalyst was prepared by calcination of Zn2(OH)2CO3 and zinc-based metal-organic framework (Zn-MOF) mixtures. The synthesized ZnO samples showed better UV light catalytic performance compared to commercially available nano-sized ZnO materials. However, the ZnO samples had poor visible-light photocatalytic performance. The presence of H2O2 accelerated the degradation of methylene blue (MB) solution in both cases.
INORGANIC CHEMISTRY COMMUNICATIONS
(2023)
Article
Chemistry, Analytical
Shichao Wang, Xiaohu Wang, Gaoqun Qiao, Xiaoyan Chen, Xinzhen Wang, Hongzhi Cui
Summary: Core-double shell-structured ZnO@In2O3@ZnO microspheres were successfully synthesized by decorating In2O3 and ZnO on the surface of ZnO hollow microspheres, exhibiting excellent gas sensing properties with high response to gases like ethanol, especially at low concentrations. This superior gas sensing performance was attributed to its high specific surface area, abundant surface defects, and radial electronic modulation mechanism.
SENSORS AND ACTUATORS B-CHEMICAL
(2021)
Article
Chemistry, Multidisciplinary
Mei-Hua Chen, Qian-Ying Lu, Yi-Ming Li, Ming-Ming Chu, Xue-Bo Cao
Summary: In this study, ZnO@ZIF-8 core-shell heterostructures were successfully synthesized, with ZIF-8 shell effectively increasing the specific surface area of ZnO nanorods. The synergistic effect between ZnO and ZIF-8 resulted in high photocatalytic activity, leading to rapid degradation of methylene blue under solar light irradiation. Additionally, the stability experiments demonstrated that the prepared ZnO@ZIF-8 nanocomposites retained over 95% of their photocatalytic activity after four cycles.
Article
Nanoscience & Nanotechnology
Ziyan Wang, Hongyan Liu, Junkai Shao, Zhenhua Li, Hao Zhang, Caixuan Sun, Guofeng Pan, Xueli Yang
Summary: In this study, core-shell AuPd nanoparticles sensitized Co3O4/ZnO@ZnO ellipsoid nanoparticles were successfully synthesized and showed significantly enhanced gas sensing properties. The gas sensing performance was greatly improved after noble metal decoration, and the synergistic effect of Au and Pd played a key role in enhancing the sensing mechanism.
Article
Chemistry, Multidisciplinary
Yu Zhong, Fengming Wang, Chuangming Liang, Zeyi Guan, Bingshang Lu, Xin He, Weijia Yang
Summary: This work presents the fabrication of ZnO@MoS2 core-shell micro/nanomaterials and their photocatalytic performances. The ZnO@MoS2 core-shell micro/nanorods heterostructures were grown using a two-step hydrothermal method. Characterization techniques including X-ray diffraction, scanning-electron microscopy, Raman spectra, and UV-visible spectra were used to confirm the structure of the ZnO@MoS2 core-shell micro/nanorods. Methylene blue was employed to evaluate the photocatalytic performance, revealing that the shape of the MoS2 shell layer depended on the growth time. Additionally, it was found that the photocatalytic performance was significantly influenced by the growth time of the MoS2 nanosheets, with the ZnO@MoS2 core-shell heterostructures grown for 6 hours showing the highest efficiency.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Physical
Aadil Waseem, Muhammad Ali Johar, Mostafa Afifi Hassan, Indrajit Bagal, Jun-Seok Ha, June Key Lee, Sang-Wan Ryu
Summary: Flexible and stable piezoelectric energy harvesters were successfully fabricated using polydimethylsiloxane-embedded m-axis GaN/Al2O3 core-shell nanowires transferred to indium-deposited flexible substrates. Optimizing the piezoelectric performance by controlling the Al2O3 shell thickness showed that a 6 nm thickness exhibited the maximum performance, with performance decreasing when the thickness was increased or decreased. The PEHs were effective in harvesting mechanical energy, even from static strain, and also demonstrated energy supply capabilities for operating a light emitting diode.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Vasu Prasad Prasadam, Ali Margot Huerta Flores, Jean-Nicolas Audinot, Naoufal Bahlawane
Summary: Solar-driven water splitting is a promising way to obtain clean H-2 energy, and the photoelectrochemical approach has attracted significant interest. The oxygen evolution reaction is seen as the stage that limits performance in this technology, highlighting the need for innovative anode materials. Metal oxide semiconductors are relevant in this respect due to their cost-effectiveness and widespread availability. In this study, a combination of chemical vapor deposition and atomic layer deposition was used to synthesize randomly oriented CNT-ZnO core-shell nanostructures, forming a porous coating that adheres well. Compared to directly coated ZnO on Si, the porous structure allows for a larger interface area with the electrolyte, resulting in a 458% increase in photocurrent density under simulated solar light. The photoelectrochemical characterization attributes this performance enhancement to the effective electron withdrawal along the carbon nanotubes (CNTs), leading to a decrease in the onset potential. As for durability, the CNT-ZnO core-shell structure exhibits enhanced photo-corrosion stability for 8 hours under illumination and with a voltage bias.
Article
Chemistry, Physical
Lin -Xi Shan, Yan Li, Ren-Cong Wang, Xiao-Xue Lian
Summary: Developing a TEA sensor is increasingly important for industrial production and life safety due to the poisonous and flammable characteristics of triethylamine. A novel ZnS@ZnO core-shell nanostructure with enhanced gas sensitivity and anti-humidity ability was prepared and showed promising application prospect in TEA detection.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Xiaoyan Song, Fangzheng Zhao, Zhipeng Wang, Runbin Ge, Jinfeng Xing
Summary: In this study, ZnO@SnO2-Pt core-shell nanofibers with a hollow structure were successfully prepared and exhibited superior gas-sensing performance, achieving higher response speed and sensitivity on the basis of reduced operating temperature. Additionally, the gas-sensing mechanism of the nanofibers was discussed in detail.
ACS APPLIED NANO MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Fan Ru, Jing Xia, Xuanze Li, Pei Liu, Peiyu Qiao, Yuye Li, Jianyu Cao, Lifeng Tian, Wenjun Zhang, Xiang-Min Meng
Summary: This report demonstrates the successful remote heteroepitaxy of single-crystalline ZnO/ZnS core/shell nanowires using amorphous HfO2 as the buffer layer. By adjusting the buffer layer thickness, zinc blende or wurtzite ZnS epilayers can be efficiently fabricated. The cathodoluminescence measurement shows that tuning of the optical properties can be achieved by preparing a heterostructure with HfO2.
Article
Materials Science, Ceramics
Yan Li, Lin-Xi Shan, Xiao-Xue Lian, Qing-Jun Zhou, Dong-Min An
Summary: The novel mesoporous ZnO@ZnS core-shell heterojunction sensor shows excellent NO2 detecting properties with a low detection threshold. The enhanced gas-sensing performance of the ZS sensor is achieved by the combination effect of the Schottky barrier and its mesoporous structure, promising significant practical application prospects in NO2 detection and monitoring.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Lucia Stein-Montalvo, Jeong-Ho Lee, Yi Yang, Melanie Landesberg, Harold S. Park, Douglas P. Holmes
Summary: In this study, we demonstrate that by restricting the active area to the shell boundary, the size of the shell can be significantly reduced, resulting in a decrease in energy input required for actuation. Through theoretical simulations and experimental validation, we elucidate the underlying mechanics of snap-through and provide an intuitive route to efficient design.
EUROPEAN PHYSICAL JOURNAL E
(2022)
Article
Engineering, Manufacturing
Yuchen Ding, Arif M. Abdullah, Martin Dunn, Kai Yu
Summary: This study investigates the influence of interfacial geometry on the bonding strength between different materials in the manufacturing of hybrid polymeric structures. Instead of relying on new chemistry or adhesive layers, the research focuses on understanding the mechanism of interfacial properties' enhancement through hierarchical structures and computational models. The findings provide valuable design guidelines for optimal mechanical performance in hybrid multifunctional polymeric products.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Review
Computer Science, Interdisciplinary Applications
Wing Kam Liu, Shaofan Li, Harold S. Park
Summary: This article presents a comprehensive historical account of the development of finite element methods, with a specific focus on developments related to solid mechanics. It provides a historical overview starting from the theoretical formulations and origins of the FEM, discussing important developments that have made the FEM the preferred numerical method for solid mechanics problems.
ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING
(2022)
Correction
Computer Science, Interdisciplinary Applications
Wing Kam Liu, Shaofan Li, Harold S. Park
ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
N. Vu-Bac, T. Rabczuk, H. S. Park, X. Fu, X. Zhuang
Summary: In this study, a novel formulation using nonlinear kinematics and material models is proposed to couple elasticity and solvent transport in stimuli-responsive gels. The identification of external stimuli to generate specific target shapes is achieved through an inverse methodology that chemomechanically couples large deformation and mass transport. Numerical examples demonstrate the capability of identifying the required external stimuli and accurately reconstructing target shapes, including those involving elastic instabilities or softening.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Lingxiao Yuan, Harold S. Park, Emma Lejeune
Summary: There has been an increased interest in applying data driven methods to mechanics problems, with a focus on predictive modeling and design of materials. However, traditional machine learning methods can be sensitive to data distribution shifts and violate the assumption of independent and identically distributed data. Out-of-distribution (OOD) generalization methods have been proposed to address this issue, but their performance on regression problems in mechanics is yet to be explored. This study investigates OOD generalization methods for mechanics-specific regression problems and suggests the need for more robust methods that can handle multiple OOD scenarios.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Materials Science, Composites
Arif M. Abdullah, Yuchen Ding, Xu He, Martin Dunn, Kai Yu
Summary: This study presents a cost-effective 3D printing method for printing UV-curable composites reinforced with continuous carbon fiber. The influences of different material and processing variables on the quality and mechanical properties of the composites are investigated. The study also demonstrates the 3D printing of composite structures and the conformal coating of curved surfaces along a defined printing path.
JOURNAL OF COMPOSITE MATERIALS
(2023)
Article
Materials Science, Composites
Connor D. Armstrong, Liang Yue, Xiao Kuang, Devin J. Roach, Martin L. Dunn, H. Jerry Qi
Summary: This paper introduces a single-stream hybrid DIW AM technique for the creation of high-strength FRPC functional structures. The technique uses DIW 3D printing for the matrix and robotically places pre-impregnated woven carbon fiber fabrics for reinforcement, while enabling easy integration of functional elements. The study demonstrates that this approach offers a simplified manufacturing process and produces mechanically robust FRPC structures.
JOURNAL OF COMPOSITE MATERIALS
(2023)
Article
Multidisciplinary Sciences
Jong-Hyun Seo, Sung-Gyu Kang, Yigil Cho, Harold S. Park, Youngdong Yoo, Bongsoo Kim, In-Suk Choi, Jae-Pyoung Ahn
Summary: Buckling is a loss of structural stability, particularly in long slender structures or thin plate structures subjected to compressive forces. This study utilizes the buckling instability of Au nanowires for electrical measurement and confirms that high-strength single crystalline Au nanowires can exhibit classical Euler buckling under constant compressive force without failure. The study suggests the use of Au nanowire probes with structural instability for stable and precise electrical measurements at the nanoscale.
Article
Physics, Applied
Li-Kai Wan, Yi-Xuan Xue, Jin-Wu Jiang, Harold S. S. Park
Summary: Lateral heterostructures of graphene/hexagonal boron nitride exhibit unique electronic and optical properties, and the mechanical properties of the interface play a crucial role in their stability. Through molecular dynamics simulations and machine learning, a study on the fracture properties of the interface in these heterostructures was conducted. It was found that the shape of the interface significantly affects the fracture stress and strain, and a machine learning model was able to identify the strongest interfaces. The findings also revealed the importance of interface roughness and chemical bond strength in determining interface strength, and the correlation between fracture properties and thermal conductivity.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Mohamed Shaat, Harold S. Park
Summary: There is significant interest in studying the functionality of odd elastic solids, which are a specific class of active matter that cannot be described by a free energy function. This paper proposes the coupling of non-symmetric elasticity with chiral, nonreciprocal elasticity as a means to achieve isotropic elastic solids exhibiting non-symmetric elasticity.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Jeong-Ho Lee, Harold S. Park, Douglas P. Holmes
Summary: Soft matter mechanics involves finite deformations and instabilities of structures in response to mechanical and non-mechanical stimuli. Modeling plates and shells is challenging due to their nonlinear response to loads, and non-mechanical loads further complicate matters by modifying the shell's energy functional. This work demonstrates a mechanical interpretation of non-mechanical stimuli, transforming their effects into effective external loadings and enabling the use of standard analytical and computational tools. The theory is validated by benchmark problems and applied to examples such as the snapping of the Venus flytrap and leaf growth.
MATHEMATICS AND MECHANICS OF SOLIDS
(2023)
Article
Chemistry, Multidisciplinary
Lijie He, Guangming Cheng, Yong Zhu, Harold S. Park
Summary: We use a hybrid diffusion- and nucleation-based kinetic Monte Carlo model to explain the significant influence of adatom diffusion on incipient surface dislocation nucleation in metal nanowires. We discover a stress-regulated diffusion mechanism that promotes the accumulation of diffusing adatoms near nucleation sites, explaining the experimental observations of temperature-dependent nucleation strength but weak strain-rate dependence. Additionally, our model shows that a decreasing rate of adatom diffusion with increasing strain rate leads to stress-controlled nucleation becoming the dominant mechanism at higher strain rates. Overall, our model provides new mechanistic insights into how surface adatom diffusion directly affects the nucleation process and mechanical properties of metal nanowires.
Article
Engineering, Mechanical
Hai D. Huynh, Xiaoying Zhuang, Harold S. Park, S. S. Nanthakumar, Yabin Jin, Timon Rabczuk
Summary: The Willis coupling, which couples momentum to strain in elastic metamaterials, has been extensively studied for its potential in enabling novel wave propagation phenomena. Recent work has shown that the momentum can also be coupled to electrical stimulus in piezoelectric composites, resulting in a new form of electro-momentum coupling. In this study, a topology optimization approach is presented to maximize the electro-momentum coupling in piezoelectric composites, allowing for the design of composites that support novel wave phenomena excited through non-mechanical means.
EXTREME MECHANICS LETTERS
(2023)
Article
Thermodynamics
Yixuan Xue, Harold S. Park, Jin-Wu Jiang
Summary: In this study, we demonstrate that the interfacial thermal resistance in graphene/fullerene/graphene sandwiches can be switchable and show a step-like change by varying the number of fullerenes. This switchable phenomenon is achieved by a structural transition between the graphene layers. The study also shows that mechanical strain or temperature variation can achieve the same switchable effect. This work highlights the potential application of sandwich-like nanoscale heterostructures in switchable thermal devices.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)