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A Sparse DAE Solver in Maple

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arXiv 2022年

作者： Jang, Taejin Uppaluri, Maitri Subramanian, Venkat R. Materials Science and Engineering Program Texas Materials Institute The University of Texas at Austin AustinTX78712 United States Walker Department of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States Oden Institute for Computational Science and Engineering The University of Texas at Austin AustinTX United States

In this paper, some adaptive single-step methods like Trapezoid (TR), Implicit-mid point (IMP), Euler-backward (EB), and Radau IIA (Rad) methods are implemented in Maple to solve index-1 nonlinear Differential Algebraic Equations (DAEs). Maple's robust and efficient ability to search within a list/set is exploited to identify the sparsity pattern and the analytic Jacobian. The algorithm and implementation were found to be robust and efficient for index-1 DAE problems and scales well for finite difference/finite element discretization of two-dimensional models with system size up to 10,000 nonlinear DAEs and solves the same in few seconds. © 2022, CC BY-NC-ND.

关键词： Differential equations

Backscattering-free edge states below all bands in two-dimensional auxetic media

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arXiv 2023年

作者： Cheng, Wenting Qian, Kai Cheng, Nan Boechler, Nicholas Mao, Xiaoming Sun, Kai Department of Physics University of Michigan Ann ArborMI48109 United States Department of Mechanical and Aerospace Engineering University of California San Diego La Jolla CA92093 United States Program in Materials Science and Engineering University of California San Diego La Jolla CA92093 United States

Unidirectional and backscattering-free propagation of sound waves is of fundamental interest in physics, and highly sought-after in engineering. Current strategies utilize topologically protected chiral edge modes in bandgaps, or complex mechanisms involving active constituents or nonlinearity. Here we propose a new class of passive, linear, one-way edge states based on spin-momentum locking of Rayleigh waves in two-dimensional media in the limit of vanishing bulk modulus, which provides 100% unidirectional and backscattering-free edge propagation at a broad range of frequencies instead of residing in gaps between bulk bands. We further show that such modes are characterized by a new topological winding number that is analogous to discrete angular momentum eigenvalues in quantum mechanics. These passive and backscattering-free edge waves have the potential to enable a new class of phononic devices in the form of lattices or continua that work in previously inaccessible frequency ranges. © 2023, CC BY.

关键词： Backscattering

Sustainable, low-cost sorbents based on calcium chloride-loaded polyacrylamide hydrogels

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arXiv 2023年

作者： Hoogendoorn, Levi Huertas, Mauricio Nitz, Phillip Qi, Naiyu Baller, Johannes Prinz, Carsten Graeber, Gustav Graeber Lab for Energy Research Chemistry Department Humboldt-Universität zu Berlin Germany Integrated Science Program Materials Science and Engineering Northwestern University Evanston United States Institute of Chemistry University of Tartu Tartu Estonia Berlin Germany

Sorbents are promising materials for applications in atmospheric water harvesting, thermal energy storage, and passive cooling, thereby addressing central challenges related to water scarcity and the global energy transition. Recently, hygroscopic hydrogel composites have emerged as high-performance sorbents. However, many of these systems are fabricated with unsustainable and costly sorbent materials, which hinders their wide deployment. Here, the synthesis of high-performance, cost-efficient polyacrylamide hydrogels loaded with unprecedented amounts of calcium chloride is demonstrated. To this end, the swelling procedure of polyacrylamide hydrogels in aqueous calcium chloride solutions is optimized. The obtained salt loading in the hydrogel is characterized as a function of temperature, calcium chloride concentration in the swelling solution, and the hydrogel preparation conditions. The obtained hydrogel-salt composites are shown to be stable under repeated sorption-desorption cycling and enable water uptakes of 0.92 and 2.38 gram of water per gram of dry materials at 30% and 70% relative humidity, respectively. The resulting cost-performance ratio substantially exceeds the state-of-the-art. The mechanistic insights on hydrogel salt interactions can guide the design of sustainable and low-cost sorbent materials for future applications in water and energy. Copyright © 2023, The Authors. All rights reserved.

关键词： Heat storage

Enhancing dye degradation in darkness: The role of SnO2 nanorod clusters in flexocatalysis

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Chemical engineering Journal 2024年 494卷

作者： Chang, Nai-Jen Chen, Yu-Ching Lai, Sz-Nian Ming Wu, Jyh Department of Materials Science and Engineering National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan Program in Prospective Functional Materials Industry National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan High Entropy Materials Center National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan

Flexoelectricity is present in all dielectric materials and exhibits spontaneous electrical polarization when subjected to a strain gradient. In the present study, low-dimensional, pinecone-like tin oxide (SnO2) nanorod clusters demonstrated favorable flexocatalytic properties during a dye degradation experiment in which light irradiation was excluded;the catalytic activity was driven solely by mechanical force. Notably, the SnO2 lattice did not have a non-centrosymmetrical structure, indicating the absence of a piezoelectric effect. However, the nanoscale structure exhibited notable flexocatalysis under ultrasonic vibration. During the aforementioned dye degradation experiment, the concentration of dye molecules underwent nearly complete degradation under ultrasonic treatment. The corresponding rate constant was 0.484 hr-1, indicating a 28-fold improvement compared with commercially available SnO2 nanoparticles. Further characterization revealed that the as-synthesized SnO2 exhibited abundant oxygen vacancies. Through heat treatment at multiple temperatures, the concentration of oxygen vacancies was systematically reduced, and this reduction demonstrated a negative correlation with dye degradation efficiency. Within this system, oxygen vacancies played a pivotal role in modifying the band structure, thereby hindering the recombination rate of electron-hole pairs. This behavior indicates a notable enhancement in flexocatalysis efficiency with the elevation of defect concentration through thermal treatment. The present study demonstrated the viability of flexocatalysis for SnO2 with a wide band gap and highlighted the synergistic effect of defects, even in the absence of light, to present a promising strategy for polluted water treatment applications. © 2024 Elsevier B.V.

关键词： Oxygen vacancies

Nanoscale Viscoelasticity Characterization of Engineered Organometallic Regenerative Tissue Scaffold Nanocomposites for Biomedical Applications

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SSRN

SSRN 2022年

作者： Yuya, Philip A. Patel, Nimitt G. Department of Mechanical and Aerospace Engineering Clarkson University PotsdamNY13699 United States Materials Science and Engineering Ph.D. Program Clarkson University PotsdamNY13699 United States

This work is focused on nanoscale viscoelastic properties characterization of gold nanoparticles (AuNPs) reinforced chitosan nanocomposites using nanoindentation. Chitosan nanocomposite films reinforced with gold nanoparticles concentration (w/v) up to 0.25 mg/ml in chitosan were prepared via a solution evaporation technique. Creep and stress relaxation responses were modeled using the generalized Voigt model and the generalized Maxwell model, respectively. Nanoindentation experimental data were analyzed using these models to obtain model constants. Both displacement- and load-controlled ramp functions were used to indent the samples with a 100 µm conospherical indenter tip. The moduli increased with an increase in AuNPs concentration in chitosan. The plasticity index increased with an increase in AuNPs concentration indicating that the deformation became more plastic with an increase in the filler. The results also show the time-dependent viscous response of the nanocomposite is mainly governed by the response of the matrix because the characteristic time scales of the nanocomposite films are independent of the AuNPs concentration. © 2022, The Authors. All rights reserved.

关键词： Creep

Recent advances in Fenton and Fenton-like reaction mediated nanoparticle in cancer therapy

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Biomedical Technology

Biomedical Technology 2023年 3卷 40-51页

作者： Huijie Han Jiachen Li Hélder A. Santos Department of Biomedical Engineering University Medical Center Groningen University of Groningen Groningen 9713 AV the Netherlands W.J. Korf Institute for Biomedical Engineering and Materials Science University Medical Center Groningen University of Groningen Groningen 9713 AV the Netherlands Drug Research Program Division of Pharmaceutical Chemistry and Technology Faculty of Pharmacy FI-00014 Helsinki Finland

Fenton and Fenton like reaction have been well clarified as efficient reactive oxygen species (ROS) sources in tumor, and have been widely developed into a cancer treatment method. Meanwhile, transition metal-based nanomaterials with Fenton or Fenton like reaction characteristics also have been well explored as therapeutic agents for the cancer therapy, mainly in chemo-dynamic and ferroptosis induced cancer therapy. Herein,to summarize recent advances in Fenton and Fenton like reaction mediated nanoparticles for cancer therapy, in this minireview, we first introduced the mechanisms of Fenton and Fenton like reaction and two therapeutic methods based on Fenton and Fenton like reaction, and then we introduced the well-designed nanoparticles with Fenton reaction or Fenton-like reaction characteristics for the cancer therapies. Finally its challenges and perspectives are discussed.

关键词： Fenton reaction Fenton like reaction Cancer therapy Chemodynamic therapy Ferroptosis

Microstructural Effect on the Corrosion Behavior of N- and P-Type Bismuth Tellurides Fabricated by Induction Melting

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SSRN

SSRN 2023年

作者： El-Makaty, Farah M. Nawaz, Muddasir Shakoor, R. Abdul Hammuda, Abdelmagid Youssef, Khaled M. Mechanical and Industrial Engineering Department Qatar University Doha2713 Qatar Qatar University Doha2713 Qatar Materials Science and Technology Graduate Program College of Arts and Sciences Qatar University Doha2713 Qatar

Numerous efforts have been made to understand and enhance the thermoelectric properties of bismuth telluride alloys. However, limited studies have been reported to investigate the corrosion behavior of these alloys and their suitability for industrial applications. This paper examines the corrosion behavior of three different bismuth telluride alloys prepared by induction melting: pristine Bi2Te3, n-type Bi2Te2.55Se0.45, and p-type Bi0.6Sb1.4Te3. The electrochemical response of the samples is tested in 3.5 wt.% NaCl solution at room temperature. Potentiodynamic polarization curves (Tafel plots) revealed that the n-type sample formed a passive layer compared to the pristine and the p-type samples, which showed pitting corrosion. The different trends observed in the samples were related to their evolved microstructures, where fingerprint-like features in the pristine and the p-type samples showed high susceptibility to pitting corrosion. In contrast, a unique needle-like microstructure of the n-type samples acted as nucleation sites for passive layer formation causing higher corrosion resistance in this sample. © 2023, The Authors. All rights reserved.

关键词： Microstructure

Graphene calorimetric single-photon detector

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arXiv 2024年

作者： Huang, Bevin Arnault, Ethan G. Jung, Woochan Fried, Caleb Russell, B. Jordan Watanabe, Kenji Taniguchi, Takashi Henriksen, Erik A. Englund, Dirk Lee, Gil-Ho Fong, Kin Chung Intelligence Community Postdoctoral Research Fellowship Program Massachusetts Institute of Technology CambridgeMA02139 United States Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States Department of Physics Pohang University of Science and Technology Pohang790-784 Korea Republic of Department of Physics Washington University in St. Louis St. LouisMO United States Research Center for Electronic and Optical Materials National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan RTX BBN Technologies Quantum Engineering and Computing Group CambridgeMA02138 United States

Single photon detectors (SPDs) [1, 2] are essential technology in quantum science, quantum network, biology, and advanced imaging [3-5]. To detect the small quantum of energy carried in a photon, conventional SPDs rely on energy excitation across either a semiconductor bandgap or superconducting gap. While the energy gap suppresses the false-positive error, it also sets an energy scale that can limit the detection efficiency of lower energy photons and spectral bandwidth of the SPD [6-8]. Here, we demonstrate an orthogonal approach to detect single near-infrared photons using graphene calorimeters [9-13]. By exploiting the extremely low heat capacity of the pseudo-relativistic electrons in graphene near its charge neutrality point [14], we observe an electron temperature rise up to ∼2 K using a hybrid Josephson junction. In this proof-of-principle experiment, we achieve an intrinsic quantum efficiency of 87% (75%) with dark count © 2024, CC BY.

关键词： Particle beams

Revisiting the Temperature Dependence of Protein Diffusion inside Bacteria: Validity of the Stokes-Einstein Equation

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Physical Review Letters 2022年第1期129卷 018101-018101页

作者： Asmaa A. Sadoon William F. Oliver Yong Wang Department of Physics University of Arkansas Fayetteville Arkansas 72701 USA Materials Science and Engineering Program University of Arkansas Fayetteville Arkansas 72701 USA Department of Physics University of Thi-Qar Nassiriya 64001 Iraq Cell and Molecular Biology Program University of Arkansas Fayetteville Arkansas 72701 USA

Although the transport and mixing of proteins and other molecules inside bacteria rely on the diffusion of molecules, many aspects of the molecular diffusion in bacterial cytoplasm remain unclear or controversial, including how the diffusion-temperature relation follows the Stokes-Einstein equation. In this study, we applied single-particle tracking photoactivated localization microscopy to investigate the diffusion of histonelike nucleoid structuring (HNS) proteins and free dyes in bacterial cytoplasm at different temperatures. Although the diffusion of HNS proteins in both live and dead bacteria increased at higher temperatures and appeared to follow the Arrhenius equation, the diffusion of free dyes decreased at higher temperatures, questioning the previously proposed theories based on superthermal fluctuations. To understand the measured diffusion-temperature relations, we developed an alternative model, in which the bacterial cytoplasm is considered as a polymeric network or mesh. In our model, the Stokes-Einstein equation remains valid, while the polymeric network contributes a significant term to the viscosity experienced by the molecules diffusing in bacterial cytoplasm. Our model was successful in predicting the diffusion-temperature relations for both HNS proteins and free dyes in bacteria. In addition, we systematically examined the predicted diffusion-temperature relations with different parameters in the model, and predicted the possible existence of phase transitions.

关键词： Anomalous diffusion Diffusion Intracellular transport Network diffusion Proteins