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An application of conjugate gradient technique for determination of thermal conductivity as an inverse engineering problem

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materials Today: Proceedings 2021年 47卷 3082-3087页

作者： Vivek Pandey Addisu Bekele Gulam Mohammed Sayeed Ahmed Nand Jee Kanu Gyanendra Kumar Singh Department of Thermal and Aerospace Engineering School of Mechanical Chemical and Materials Engineering Adama Science and Technology University Adama Ethiopia Centre of Excellence for Advanced Manufacturing Engineering Program of Mechanical Design and Manufacturing Engineering School of Mechanical Chemical and Materials Engineering Adama Science and Technology University Adama Ethiopia Department of Mechanical Engineering S. V. National Institute of Technology Surat India Department of Mechanical Design and Manufacturing Engineering School of Mechanical Chemical and Materials Engineering Adama Science and Technology University Adama Ethiopia

Inverse problems frequently occur when boundary conditions/thermal properties of a material are unknown, and are determined from known internal temperature measurements. A direct problem is the opposite of an inverse problem. For example, it would be the task of determining the temperature field within a material body, given boundary conditions and thermal properties. In an ill-posed, inverse problem, small variations in internal temperature measurement cause large variations in the estimated quantity such as boundary heat flux. Measured temperature variations may be due to noise, measurement error and instrumentation error, among other factors. There are various methods for solving inverse problems in materials engineering. In the paper, an inverse problem of estimating boundary heat flux for one-dimensional heat conduction is solved using the classical method of Beck and temperature dependent thermal conductivity is estimated using the more recent and advanced Conjugate Gradient method (CGM). The temperature values from the finite difference application to a direct heat transfer problem are used along with noise added to the data, in order to simulate real world, experimental conditions. The data is applied to the inverse problem of finding boundary heat flux and thermal conductivity. It is seen that Conjugate Gradient Method (CGM) along with sequential function specification method recovers the boundary heat flux and thermal conductivity quite accurately for noise levels of 1% and 2%. It is further observed that addition of future time steps stabilize the algorithm and increase accuracy of the desired results. It is also observed that CGM can recover the temperature dependent thermal conductivity quickly within few iterations, for different values of thermal conductivity function coefficients, k 0 and k 1 . CGM is found to be fast and robust when applied to one-dimensional case and can be extended to complex geometries.

关键词： Inverse problem Thermal conductivity Conjugate gradient

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Chloride-assisted synthesis of tellurene directly on SiO 2 /Si substrates: growth mechanism, thermal properties, and device applications †

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materials Advances 2023年第8期4卷 2008-2016页

作者： Yi-Hsun Chan Che-Yi Lin Yu-Chang Chou Alice Chinghsuan Chang Yen-Fu Lin Yu-Ze Chen Department of Materials Science and Engineering National Cheng Kung University Tainan City 70101 Taiwan yzchen@gs.ncku.edu.tw Department of Physics National Chung Hsing University Taichung 40227 Taiwan Center for Measurement Standards Industrial Technology Research Institute Hsinchu 30011 Taiwan Department of Materials Science and Engineering National Chung Hsing University Taichung 40227 Taiwan Institute of Nanoscience National Chung Hsing University Taichung 40227 Taiwan i-Center for Advanced Science and Technology (i-CAST) National Chung Hsing University Taichung 40227 Taiwan Program on Key Materials Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan City 70101 Taiwan

The new single-element two-dimensional materials in the post-graphene era, such as phosphorene and silicene, are emerging as alternative next-generation materials due to their remarkable physical properties. However, the vulnerability of silicene and phosphorene to the air hinders their practical applications. Recently, a new kind of single-element two-dimensional material, namely tellurene, exhibiting outstanding electrical mobility and superior long-term stability in the air, has been successfully synthesized. Here, we report that the addition of chloride (TeCl 4 ) to TeO 2 is conducive to the lateral growth of tellurium on the SiO 2 /Si substrate. The resulting tellurene flakes display outstanding structure stability over 30 days under ambient exposure. Furthermore, the applicability of SThM (scanning thermal microscopy) to investigate the thermal properties of tellurene is presented for the first time, revealing its abnormal thermal conductance across grain boundaries and a thickness-dependent thermal transport behavior. Finally, tellurene-based FETs (field effect transistors) were fabricated, which displayed temperature-dependent I ds that decreased with decreasing temperature rather than metallic transport features, which implies thermal activation of a semiconductor and confirms that the transport follows the 2D variable-range hopping (VRH) model.

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BEAST DB: Grand-Canonical Database of Electrocatalyst Properties

arXiv

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arXiv 2024年

作者： Tezak, Cooper Clary, Jacob Gerits, Sophie Quinton, Joshua Rich, Benjamin Singstock, Nicholas Alherz, Abdulaziz Aubry, Taylor Clark, Struan Hurst, Rachel Ben, Mauro Del Sutton, Christopher Sundararaman, Ravishankar Musgrave, Charles Vigil-Fowler, Derek Department of Chemical and Biological Engineering University of Colorado Boulder BoulderCO80309 United States Materials Chemical and Computational Science Directorate National Renewable Energy Laboratory GoldenCO80401 United States Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute TroyNY12180 United States Department of Chemistry University of Colorado Boulder BoulderCO80309 United States Department of Mechanical Engineering University of Colorado Boulder BoulderCO80309 United States Department of Chemical Engineering College of Engineering and Petroleum Kuwait University Safat13060 Kuwait Applied Mathematics & Computational Research Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Chemistry and Biochemistry University of South Carolina ColumbiaSC29208 United States Department of Materials Science and Engineering Rensselaer Polytechnic Institute TroyNY12180 United States Materials Science and Engineering Program University of Colorado Boulder BoulderCO80309 United States Renewable and Sustainable Energy Institute University of Colorado Boulder BoulderCO80309 United States Department of Chemical Engineering University of Utah Salt Lake CityUT84112 United States

We present BEAST DB, an open-source database comprised of ab initio electrochemical data computed using grand-canonical density functional theory in implicit solvent at consistent calculation parameters. The database contains over 20,000 surface calculations and covers a broad set of heterogenous catalyst materials and electrochemical reactions. Calculations were performed at self-consistent fixed potential as well as constant charge to facilitate comparisons to the computational hydrogen electrode. This article presents common use cases of the database to rationalize trends in catalyst activity, screen catalyst material spaces, understand elementary mechanistic steps, analyze electronic structure, and train machine learning models to predict higher fidelity properties. Users can interact graphically with the database by querying for individual calculations to gain granular understanding of reaction steps or by querying for an entire reaction pathway on a given material using an interactive reaction pathway tool. BEAST DB will be periodically updated, with planned future updates to include advanced electronic structure data, surface speciation studies, and greater reaction coverage. Copyright © 2024, The Authors. All rights reserved.

关键词： Database systems

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Nanoscale Manipulation of Single-Molecule Conformational Transition through Vibrational Excitation

arXiv

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arXiv 2024年

作者： Quan, Weike Wang, Zihao Shi, Yueqing Liang, Kangkai Bi, Liya Zhou, Hao Yin, Zhiyuan Li, Wan-Lu Li, Shaowei Department of Chemistry and Biochemistry University of California La Jolla San DiegoCA92093-0309 United States Program in Materials Science and Engineering University of California La Jolla San DiegoCA92093-0418 United States Aiiso Yufeng Li Family Department of Chemical and Nano Engineering University of California La Jolla San DiegoCA92093-0448 United States

On-demand control of molecular actions is essential for realizing single-molecule functional devices. Such a control can be achieved by manipulating interactions between individual molecules and their nanoscale environment. In this study, we manipulate the conformational transition of a single pyrrolidine molecule on a Cu(100) surface by exciting its vibrations with tunneling electrons using scanning tunneling microscopy. Multiple transition pathways between two structural states are identified to be driven by distinct vibrational modes, whose corresponding nuclear motions are determined by density functional theory calculations. Tip-induced van der Waals forces and intermolecular interactions enable precise tuning of molecule-environment interactions, allowing modulation of vibrational energies, alteration of transition probabilities, and selection of the lowest energy transition pathway. This work reveals how external force fields in a tunable nanocavity can modulate molecular conformational transitions, offering an approach to deliberately engineer molecule-environment interactions for specific molecular functions. © 2024, CC BY.

关键词： Van der Waals forces

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Chiral metal-organic framework based spin-polarized flexible photodetector with ultrahigh sensitivity

引用

materials Today Nano 2023年 21卷

作者： Mustaqeem, M. Kamal, S. Ahmad, N. Chou, P.-T. Lin, K.-H. Huang, Y.-C. Guo, G.-Y. Paul Inbaraj, C.R. Li, W.-K. Yao, H.-C. Lu, K.-L. Chen, Y.-F. Department of Chemistry National Taiwan University No. 1 Section 4 Roosevelt Rd Taipei10617 Department of Physics National Taiwan University No. 1 Section 4 Roosevelt Rd Taipei10617 Nano-Science and Technology Program Taiwan International Graduate Program Institute of Physics Academia Sinica Taipei106 Taiwan Institute of Chemistry Academia Sinica Taipei115 Taiwan Department of Materials Science and Engineering National Taiwan University of Science and Technology Taipei10607 Taiwan Institute of Physics Academia Sinica Taipei11529 Taiwan Department of Materials Engineering Ming Chi University of Technology

Spin-optoelectronics plays a key role in developing next-generation technologies with potential applications covering from pharmaceutical synthesis and quantum computing to optical communication. One of the most feasible ways to achieve high-performance spin optoelectronic devices is based on chiral materials. Chiral metal-organic frameworks (CMOFs), an emerging class of chiral hybrid materials, have sparked interest due to their structural variety and flexibility, order nanopores, cost-effectiveness, and unique chirality features. Herein, we have developed CMOF [Sr (9,10-adc) (DMAc)2]n based on achiral building blocks [(9,10-adc)] to detect circularly polarized light (CPL) with ultrahigh sensitivity. Their application in spin-polarized flexible detectors gives a detectivity (D∗) as high as 1.83 × 1012 jones, superior to all reported heterochiral MOF-based detectors. Meanwhile, the anisotropy factor (gIph) is up to 0.38 for CPL detection. The maximum photoresponsivity (Rph) and photogain (η) values of CMOFs reach up to 6.0 × 105 (A/W) and 1.8 × 106, respectively, which are also the record values among reported chiral MOFs. Additionally, the photodetector is mechanically flexible and durable, manifesting an important feature for wearable devices. Therefore, our study shown here is significant and timely to open a route for advancing spin-optoelectronics based on CMOF. © 2023 Elsevier Ltd

关键词： Photodetectors

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Ti-Nb-Zr Ternary Alloy Coatings Sputter Deposited on Aisi 316l Stainless Steel

SSRN

引用

SSRN 2023年

作者： Lemos, Lucas L.D. de Castro, Ana Luiza Costa, Sidney C.Z. Mastelaro, Valmor Roberto Nascente, Pedro A.P. Graduate Program in Materials Science and Engineering Federal University of Sao Carlos SP Sao CarlosCEP 13565-905 Brazil Sao Carlos Institute of Physics University of Sao Paulo SP Sao CarlosCEP 13560-590 Brazil Department of Materials Engineering Federal University of Sao Carlos SP Sao CarlosCEP 13565-905 Brazil

Titanium, niobium, and zirconium are non-toxic and non-allergenic biocompatible metals, and the ternary Ti-Nb-Zr bulk alloys having predominantly β phase (body-centered cubic structure) present superior corrosion resistance and biocompatibility than medical grade AISI 316L stainless steel (SS) which is commonly used as metallic prosthetic material. However, the Ti-Nb-Zr alloys are much more costly than SS, so the main goal of this study is to produce and characterize lesser costly Ti-Nb-Zr coatings. Magnetron sputtering has shown to be an adequate technique to coat SS surfaces with Ti-based alloys. Three ternary alloy coatings having approximately the same amount of Zr (12-14 at.%) and different amounts of Ti (76, 62, and 53 at.%) and Nb (10, 26, and 34 at.%) were deposited on AISI 316L SS by magnetron sputtering. Only the β phase was detected and the coating surfaces were oxidized, having a beneficial effect on corrosion resistance and presents lesser cytotoxicity. The elastic moduli were evaluated by nanoindentation tests, and the obtained values were smaller than that for the SS substrate. These findings suggest that the Ti-Nb-Zr ternary alloy coatings have promising characteristics for biomedical applications. © 2023, The Authors. All rights reserved.

关键词： Magnetron sputtering

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Fabrication of tantalum silicate films with low TCR and low resistivity by magnetron sputtering

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Vacuum 2024年 226卷

作者： Chen, Cheng-Lung Huang, Cheng Chen, Sheng-Chi Liu, Yen-Chen Chuang, Min-Chen Wen, Chao-Kuang Huang, Wei-Sheng Yang, Wen-Sheng Chen, Yang-Yuan Graduate School of Materials Science National Yunlin University of Science and Technology Yunlin64002 Taiwan Department of Materials Engineering and Center for Plasma and Thin Film Technologies Ming Chi University of Technology 243 New Taipei City Taiwan College of Engineering and Center for Green Technology Chang Gung University 333 Taoyuan Taiwan International Ph.D. Program in Plasma and Thin Film Technology Ming Chi University of Technology 243 New Taipei City Taiwan TPH Research & Develop Dept. Chien Hwa Coating Technology Inc. Hsinchu300 Taiwan National Engineering Research Center for Rare Earth Materials Grirem Advanced Materials Co. Ltd. General Research Institute for Nonferrous Metals Beijing100088 China Institute of Physics Academia Sinica 115 Taipei Taiwan

Tantalum silicate (Ta–Si–O) thin film materials have gained significant interest in hybrid renewable energy systems and thin-film resistors due to their exceptional thermal stability and adjustable electrical properties. In this study, we investigated the effects of target compositions and sputtering power densities on the material structures, chemical compositions, microstructures, and electrical properties of Ta–Si–O films. Two target compositions, Ta65(SiO2)35 and Ta80(SiO2)20, were utilized in the deposition process. Notably, we observed substantial variations in the temperature coefficient of resistance (TCR) value and resistivity of Ta–Si–O thin films with different Ta concentrations. Most importantly, when the Ta content of the film is controlled at 62 ± 0.6 % by using this target, the resistivity of the Ta0.62Si0.20O0.18 film can be as small as 2.31 ± 0.05 × 10−4 Ω-cm and has an extremely small TCR of 22 ± 0.4 ppm/°C, which shows an excellent opportunity for the development of precision thin film resistors. A TCR value close to zero can be finely tuned by controlling the Ta concentration in the Ta–Si–O film. These intriguing electrical behaviors were found to be highly correlated with the predominant formation of metallic Ta5Si3 as the main structural phase in the films. This work presents a simple and effective approach to produce Ta–Si–O thin films with near-zero TCR, making them highly suitable for applications under high-temperature conditions. Our findings contribute to the development of tailored thin film materials with desirable electrical properties for advanced electronic and energy devices. © 2024 Elsevier Ltd

关键词： Thin films

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Nanoslot-Induced Ultrastrong Phonon-Photon and Phonon-Phonon Coupling in Hybrid Organic-Inorganic Perovskites 16

Nanoslot-Induced Ultrastrong Phonon-Photon and Phonon-Phonon...

引用

16th Pacific Rim Conference on Lasers and Electro-Optics, CLEO-PR 2024

作者： Kim, Dasom Hou, Jin Lee, Geon Agrawal, Ayush Kim, Sunghwan Zhang, Hao Bao, Di Baydin, Andrey Wu, Wenjing Tay, Fuyang Huang, Shengxi Hagenmüller, Daivd Chia, Elbert E. M. Kim, Dai-Sik Seo, Minah Mohite, Aditya D. Kono, Junichiro Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States Sensor System Research Center Korea Institute of Science and Technology Seoul02792 Korea Republic of Department of Physics and Astronomy Seoul National University Seoul08826 Korea Republic of Department of Chemical and Biomolecular Engineering Rice University HoustonTX77005 United States Ulsan44919 Korea Republic of Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 637371 Singapore Smalley-Curl Institute Rice University HoustonTX77005 United States Université de Strasbourg Cnrs Strasbourg67000 France KU-KIST Graduate School of Converging Science and Technology Korea University Seoul02841 Korea Republic of Department of Physics and Astronomy Rice University HoustonTX77005 United States

Methods for harnessing vibrational states are desired for phonon-based technologies. We realized ultrastrong coupling of two phonon modes in perovskite materials induced by ultrastrong coupling with a common photonic ... 详细信息

ISBN: (纸本)9798350372076

关键词： Organic-inorganic materials

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Surface surgery on TiNb2O7 electrode via N2/Air atmospheric pressure plasma jet for high-rate lithium-ion battery anode

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Applied Surface science 2024年 655卷

作者： Wu, Che-Ya Hsiao, Shih-Nan Kuo, Rui-Tung Chen, Yu-Ching Lin, Tzu-Ying Hori, Masaru Duh, Jenq-Gong Department of Materials Science and Engineering National Tsing Hua University No. 101 Sec. 2 Kuang-Fu Road Hsinchu300 Taiwan Nagoya University Furo-cho Aichi Chikusa Nagoya464–8603 Japan Program in Prospective Functional Materials Industry National Tsing Hua University No. 101 Sec. 2 Kuang-Fu Road Hsinchu300 Taiwan

TiNb2O7 (TNO) is regarded as a potential anode material for its high capacity compared to Li4Ti5O12 and high safety due to its adequate Fermi level in lithium-ion batteries. This work represents a promising method of modifying the electrode, which includes polyvinylidene fluoride (PVDF), conductive carbon, and TiNb2O7, using an atmospheric pressure plasma jet (APPj) treatment. Our results reveal that atmospheric pressure plasma jet improves the electrochemical performance by N-doped decoration on conductive carbon, electrolyte wettability enhancement on polyvinylidene fluoride binder, and defects manufacturing in TiNb2O7 anode materials. Good wettability of surface free energy to 44.6 mJ/m2 in the APPj-treated (APP-10) sample contributes to improved cycling performance. Both N-doped carbon and modified TiNb2O7 promote the high-rate capability. The C-rate performance of APP-10 improves by over 200 % at 10C compared to the non-treated sample (APP-0). APP-10 sample also shows 81.9 % retention after 300 cycles at 1C. The formation of Li3N or LiNxOy after cycling due to the nitro-group in the electrode with atmospheric pressure plasma jet offers good protection and high ionic-conductivity interface. This work demonstrates a potential solution to achieve a roll-to-roll modification without any complex synthesis processes, which is a promising technology for the affordable manufacturing of lithium-ion battery. © 2024 Elsevier B.V.

关键词： Wetting

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Architecture Optimization Dramatically Improves Reverse Bias Stability in Perovskite Solar Cells: A Role of Polymer Hole Transport Layers

arXiv

引用

arXiv 2023年

作者： Jiang, Fangyuan Shi, Yangwei Rana, Tanka R. Morales, Daniel Gould, Isaac McCarthy, Declan P. Smith, Joel Christoforo, Grey Contreras, Hannah Barlow, Stephen Mohite, Aditya D. Snaith, Henry Marder, Seth R. MacKenzie, J. Devin McGehee, Michael D. Ginger, David S. Department of Chemistry University of Washington SeattleWA98195 United States Molecular Engineering & Sciences Institute University of Washington SeattleWA98195 United States Department of Materials Science and Engineering University of Washington SeattleWA98195 United States Materials Science and Engineering Program University of Colorado Boulder BoulderCO80309 United States Renewable and Sustainable Energy Institute University of Colorado Boulder BoulderCO80303 United States Department of Physics University of Oxford Parks Road OxfordOX1 3PU United Kingdom Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States Department of Chemical and Biological Engineering Department of Chemistry University of Colorado Boulder BoulderCO80303 United States Department of Mechanical Engineering University of Washington SeattleWA98195 United States

We report that device architecture engineering has a substantial impact on the reverse bias instability that has been reported as a critical issue in commercializing perovskite solar cells. We demonstrate breakdown voltages exceeding -15 V in typical p-i-n structured perovskite solar cells via two steps: i) using polymer hole transporting materials;ii) using a more electrochemically stable gold electrode. While device degradation can be exacerbated by higher reverse bias and prolonged exposure, our as-fabricated perovskite solar cells completely recover their performance even after stressing at -7 V for 9 hours both in the dark and under partial illumination. Following these observations, we systematically discuss and compare the reverse bias driven degradation pathways in perovskite solar cells with different device architectures. Our model highlights the role of electrochemical reaction rates and species in dictating the reverse bias stability of perovskite solar cells. Copyright © 2023, The Authors. All rights reserved.

关键词： Perovskite solar cells

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