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arXiv 2023年

作者： Kim, Hyunseung Choi, Haeyeon Kang, Dongju Lee, Won Bo Na, Jonggeol School of Chemical and Biological Engineering Seoul National University Korea Republic of Department of Chemical Engineering and Materials Science Ewha Womans University Korea Republic of Graduate Program in System Health Science and Engineering Ewha Womans University Korea Republic of

The goal of most materials discovery is to discover materials that are superior to those currently known. Fundamentally, this is close to extrapolation, which is a weak point for most machine learning models that learn the probability distribution of data. Herein, we develop reinforcement learning-guided combinatorial chemistry, which is a rule-based molecular designer driven by trained policy for selecting subsequent molecular fragments to get a target molecule. Since our model has the potential to generate all possible molecular structures that can be obtained from combinations of molecular fragments, unknown molecules with superior properties can be discovered. We theoretically and empirically demonstrate that our model is more suitable for discovering better compounds than probability distribution-learning models. In an experiment aimed at discovering molecules that hit seven extreme target properties, our model discovered 1,315 of all target-hitting molecules and 7,629 of five target-hitting molecules out of 100,000 trials, whereas the probability distribution-learning models failed. Moreover, it has been confirmed that every molecule generated under the binding rules of molecular fragments is 100% chemically valid. To illustrate the performance in actual problems, we also demonstrate that our models work well on two practical applications: discovering protein docking molecules and HIV inhibitors. © 2023, CC BY-NC-SA.

关键词： Probability distributions

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Quantifying Electrochemical Processes in Batteries and Beyond

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Energy & Environmental Materials 2022年第4期5卷 1001-1004页

作者： Emma N.Antonio Michael F.Toney Materials Science and Engineering Program University of Colorado BoulderBoulderColorado 80309USA Joint Center for Energy Storage Research(JCESR) University of Colorado BoulderBoulderColorado 80309USA Department of Chemical and Biological Engineering University of Colorado BoulderBoulderColorado 80309USA Renewable and Sustainable Energy Institute University of Colorado BoulderBoulderColorado 80309USA

The correlation of electrochemical measurements with materials characterization has advanced our understanding of operation and degradation mechanisms in electrochemical energy storage and many other ***,often these correlations are qualitative,preventing the unambiguous identification of both operational principles and the root causes of performance *** we suggest quantitative approaches to define competing mechanisms and determine their relative *** illustrate the importance of quantitative methodologies over a range of electrochemical systems and highlight the need to consider the effect of the experimental design and measurement *** approaches will reveal the most detrimental degradation mechanisms and enable the development of strategies to suppress,stabilize or eliminate them,leading to materials and devices with longer lifetimes,reduced environmental impact,and improved performance.

关键词： electrochemistry in situ and operando characterization batteries quantification materials science

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Slenderness Ratio and Material Optimization of an Impact-Resistant 2d Auxetic Lattice

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SSRN 2024年

作者： Zhai, Xuedong Heye-Smith, Karina Mao, Xiaoming Arruda, Ellen M. Department of Mechanical Engineering University of Michigan Ann ArborMI United States Department of Physics University of Michigan Ann ArborMI United States Department of Biomedical Engineering University of Michigan Ann ArborMI United States Program in Macromolecular Science and Engineering University of Michigan Ann ArborMI United States

It is well known that armor prevents failures of behind-armor targets by reducing the force in an impact event and thereby providing protection under certain impact events. However, the kinetic energy associated with an impact, often underappreciated in impact events, can be as fatal as the force by causing relative motion in the target and destructive damage as a consequence. Therefore, efficient protection gear and packaging should be lightweight and good at force reduction as well as energy mitigation. Although auxetic lattices have been studied as lightweight alternatives for force reduction, simultaneous optimization of force reduction and energy dissipation in impact mitigation via geometric and material choices for auxetic lattices has not been addressed. In the present study, we show that a 2D auxetic lattice with an optimized slenderness ratio of the struts that comprise the lattice and optimized elastic and visco-elastic material properties can not only reduce the transmitted peak force but also mitigate the energy significantly. A multi-step optimization method using Finite Element (FE) analysis and a verification procedure via impact experiments are described by which an optimal design of the auxetic lattice can be achieved by simultaneously considering both peak force and energy mitigation. © 2024, The Authors. All rights reserved.

关键词： Armor

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Mechanistic Study on Hydrogen Effects in Propylene Polymerization with Mgcl2-Supported Ziegler-Natta Catalysts: New Evidences from Active Center Counting and Reaction Kinetics

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SSRN 2023年

作者： Hu, Jie Shen, Xianrong Fu, Zhisheng Wang, Qi Fan, Zhiqiang MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University Hangzhou310027 China School of Chemical and Environmental Engineering Anhui Polytechnic University Wuhu241000 China

Propylene polymerizations catalyzed by MgCl2/Di/TiCl4-AlEt3/siloxane in the absence and presence of hydrogen were studied by determining the time-dependent changes of catalytic activity, number of active centers and active center distribution. Three types of active centers with high, medium and very low stereoselectivity were differentiated by fractionating the polymer into three parts. Chain propagation rate constant of each type of active centers was estimated by linear fitting/extrapolating the time-dependent change of apparent propagation rate constant. The centers with high (Ci*), medium (Cm*) and low (Ca*) stereoselectivity responded to addition of hydrogen differently. Adding hydrogen caused marked increase of Ci*, but its propagation rate constant (kpi) was evidently reduced. In contrast, numbers of Cm* and Ca* were only slightly affected, but their propagation rate constants were evidently enhanced by hydrogen. The different hydrogen responses of Ci* with those of Cm* and Ca* were explained by two kinds of hydrogen activation mechanisms. © 2023, The Authors. All rights reserved.

关键词： Hydrogen

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Crystallization of POSS in a PEG-Based Multiblock Polyurethane: Toward A Hybrid Hydrogel

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MRS Online Proceedings Library 2021年第1期847卷 59-64页

作者： Jian Wu Qing Ge Kelly A. Burke Patrick T. Mather Chemical Engineering Department and Polymer Program Institute of Materials Science University of Connecticut Storrs USA Department of Macromolecular Science and Engineering Case Western Reserve University Cleveland USA

Building upon earlier success in forming materials with crystalline ordering of POSS via the telechelic architecture with POSS end-capping polyethylene glycols, here we report similar ordering in PEG-POSS thermoplastic polyurethane applicable to a novel hybrid hydrogel. Thus, a unique series of hybrid thermoplastic polyurethanes (TPUs) were synthesized using poly(ethylene glycol) (PEG) as soft segment and incorporating an isobutyl-functionalized POSS diol (TMP POSS diol) in the hard segment. The molecular weight of PEG was systematically varied to include 10, 20, and 35 kDa while the mole ratio of PEG to POSS diol (as chain extender) was chosen as 8:1. The diisocyanate employed for TPU polymerization was 4, 4'-methylenebis(phenyl-isocyanate) (MDI). Wide-angle X-ray diffraction (WAXD) studies revealed that both the hydrophilic soft segments (PEG) and hydrophobic hard segments (POSS) can form crystalline structures driven by micro-phase separation, itself due to thermodynamic incompatibility. Differential scanning calorimetry (DSC) and rheological studies revealed that thermal history is important in controlling the crystallization of a POSS-rich nanophase. Increasing the cooling rate monotonically decreases the crystallinity of POSS-rich phase and results in a decrease in the ultimate dynamic storage modulus following POSS crystallization and an increase of the loss angle for temperatures above Tm of PEG and below Tm of POSS. We conclude that both composition and thermal history are key factors in determing the internal network built by the POSS nanophase, which will have a significant influence on the properties of the resulting hybrid hydrogels now being studied.

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Design and optimization of a fluid flow splitting device for low-flow applications

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SLAS Technology 2025年 32卷 100305页

作者： Yates, Alexis K. Murray, Heather N. Lippmann, Ethan S. Interdisciplinary Materials Science Program Vanderbilt University NashvilleTN United States Chemical and Biomolecular Engineering Department Vanderbilt University NashvilleTN United States

Microfluidic devices are defined by the application of fluid flow to micron-scale features. Inherent to most experiments involving microfluidic devices is the need to precisely and reproducibly control fluid flow at the microliter scale, often through multiple inlet ports on a single device. While the number of fluid channels per device varies, perfusing multiple inputs requires either the use of multiple flow controllers (often syringe or peristaltic pumps) or the ability to evenly divide fluid across outlets. Towards the latter approach, while a handful of commercial systems exist for splitting fluid flow, these set-ups require significant financial investment, multiple flow control and sensing components, and restrict the user to a predetermined perfusion control system. Simple in-line splitting devices, such a manifolds or T junctions, fail to achieve flow splitting at low flow rates often used in microfluidic systems. To increase capabilities for flow-controlled experiments, we performed experimental analyses of the physical considerations governing even flow splitting under low flow, leading to the design of a microdevice (µ-Split) that can be directly inserted into existing microfluidic set-ups. The µ-Split allows for reproducible, even flow splitting from 10 uL/min to > 2.5 mL/min. By testing multiple device geometries in combination with multiphysics simulations, we identified the design and fabrication features underlying the splitting precision achieved by the µ-Split. Overall, this work provides a useful tool to simplify microfluidic experiments that require evenly divided flow streams, while minimizing the overall device footprint. © 2025

关键词： Microfluidics

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Novel ruthenium-based catalysts with atomic dispersion for oxygen evolution reaction in water electrolysis

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Materials Today Chemistry 2024年 35卷

作者： Liao, Kuo-Wei Chen, Hsueh-Yu Wei, Wen-Hui Chen, Guan-Cheng Yamanaka, Ichiro Liu, Bo-Tau Hong, Ting-Fu Chiang, Tai-Chin Huang, Hsin-Chih Wang, Chen-Hao Department of Materials Science and Engineering National Taiwan University of Science and Technology Taipei106335 Taiwan Department of Chemical Science and Engineering School of Materials and Chemical Technology Tokyo Institute of Technology Meguro-ku Tokyo152-8552 Japan Department of Chemical and Materials Engineering National Yunlin University of Science and Technology Yunlin640301 Taiwan Department of Materials Engineering National Pingtung University of Science and Technology Pingtung912301 Taiwan Global Development Engineering Program National Taiwan University of Science and Technology Taipei106335 Taiwan Advanced Manufacturing Research Center National Taiwan University of Science and Technology Taipei106335 Taiwan

This study introduces a method for fabricating ultra-high-performance catalysts designed for the oxygen evolution reaction (OER), employing a combination of ball-milling, autoclave heat treatment procedures, and a two-step heat treatment approach. This method produces catalysts characterized by an atomic dispersion of ruthenium on nitrogen-doped carbon sheets (Ru–O/N–C–NH3). The Ru–O/N–C–NH3 catalyst exhibits exceptional OER activity in alkaline conditions, achieving a mass activity of 16842 A g−1Ru at 1.52 V, and a minimal overpotential of 290 mV at a current density of 10 mA cm−2. Moreover, this catalyst demonstrates enduring stability, showing no significant decay after a 100-h stability test in anion exchange membrane water electrolysis (AEMWE), with a mass activity approximating 62000 A g−1PGM. This is nearly three orders of magnitude greater than the AEMWE that utilizes commercial IrO2 as an anode. The atomic dispersion and the Ru–O/N bonding of the catalyst are substantiated to contribute to the notable enhancement in OER activity. © 2023 Elsevier Ltd

关键词： Ruthenium

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Review:Fabrication and Application of Zwitterion-based Functional Coatings

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Journal of Harbin Institute of Technology(New Series) 2022年第6期29卷 9-26页

作者： Jinyan Tan Shuxue Zhou A.Catarina C.Esteves Limin Wu Department of Materials Science State Key Laboratory of Macromolecular EngineeringAdvanced Coatings Research Center of Ministry of Education of ChinaFudan UniversityShanghai 200433China Laboratory of Physical Chemistry Department of Chemical Engineering and ChemistryEindhoven University of TechnologyEindhoven 5600 MBThe Netherlands Institute for Complex Molecular Systems(ICMS) Eindhoven University of TechnologyEindhoven 5600 MBThe Netherlands

Zwitterion-based materials by virtue of their special physical and chemical characteristics have attracted researchers to utilize them for fabricating functional coatings. The simultaneous presence of positive and negative charges renders the zwitterion-based materials with electrostatically induced hydration properties, which enables a high resistance towards oily pollutants, nonspecific protein adsorption, bacterial adhesion and biofilm formation. This review starts from the working mechanism of zwitterions and covers the fabrication strategies of zwitterion-based functional coatings, namely the zwitterion-bearing binder route, the zwitterion-bearing additive route and the post-generation of coatings containing zwitterionic precursors. The applications of zwitterion-based functional coatings are discussed, including medical implants, marine antifouling and oil-resistant coatings, with focus on the relevant mechanisms of the zwitterion-containing coatings for a specific performance. Finally, some comments and perspectives on the current situation and future development of zwitterion-based functional coatings are given.

关键词： zwitterionic materials functional coatings medical implant coatings marine antifouling coatings oil-resistant coatings amphiphilic coatings degradable coatings

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The analysis of characterization of zeolite modified from fly ash using iron oxide and manganese oxide 7

The analysis of characterization of zeolite modified from fl...

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7th International Conference on Advanced Materials for Better Future, ICAMBF 2022

作者： Saputro, S. Mahardiani, L. Masykuri, M. Yamtinah, S. Solikah, A.A. Yuanitama, A.L. Romantika, H.R. Azizah, I.N. Amri, A. Doctorate Program of Science Education Faculty of Teacher Training and Education Universitas Sebelas Maret Surakarta57126 Indonesia Chemistry Education Department Faculty of Teacher Training and Education Universitas Sebelas Maret Surakarta57126 Indonesia Department of Chemical Engineering University of Riau Pekanbaru28293 Indonesia

Fly ash is the residue from burning coal in the form of fine and light particles and can be harmful to the environment and life. Whereas fly ash contains high silica so that it can be used as a precursor for zeolite blinding. Zeolite as an adsorbent for aquatic waste needs to be improved so that it can absorb more adsorbate. Therefore, it is necessary to modify the zeolite from fly ash, such as coating with manganese and iron oxide. The zeolite is made from fly ash extraction and synthesize using hydrothermal method. In this study, it was found that fly ash contains about 45.20% silica and the synthetic zeolite was successfully coated with manganese and iron oxide evidenced by the results of FTIR and XRD. This is indicated by the presence of manganese oxide at an absorption of 453.29 cm-1 using FTIR and manganese oxide on XRD aimed at 2θ = 37.356°;47.337°;51,879°;57.966°;61.822° and 67.5552°. Meanwhile, the FTIR results of iron oxide were indicated by the presence of an absorption band at 447.50 cm-1 and XRD diffraction peaks at 2θ = 30,643° and 2θ = 60,322°. © Published under licence by IOP Publishing Ltd.

关键词： Fly ash

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Occurrence of cadmium in groundwater in China: a review

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Arabian Journal of Geosciences 2022年第17期15卷 1-13页

作者： Hoareau, Carol Emilly Hadibarata, Tony Yılmaz, Murat Environmental Engineering Program Faculty of Engineering and Science Curtin University Malaysia Miri Malaysia Department of Chemical Engineering Faculty of Engineering Osmaniye Korkut Ata University Osmaniye Türkiye

China has one of the world’s fastest-growing economies due to its increase in various industrial activities. A side effect of economic growth is severe environmental problems such as heavy metal contamination of soil and groundwater. Anthropogenic activities are the main sources of cadmium which is highly mobile and toxic with the potential to bioaccumulate in the ecosystem. It can contaminate ground and river water consequently negatively impacting agriculture and water sources. Anthropogenic source of Cd concentrations in China is 0.002 mg/L in drinking water, 0.102 mg/kg in soil, and 0.23–0.96 mg/kg in paddy soil. Geological trends and health implications of cadmium contamination in Human, southern China were analyzed. Source, transportation, and various conventional remediation processes exist today and can be categorized as biological, physical, and chemical. Using nanoparticle technology, it has been found that adsorption capacities can be 3 to 4 times higher compared to using powdered activated carbon. From the experiment carried out, a maximum adsorption capacity of 10.86 mg/g for cadmium was obtained. Cadmium intake in south China populations occurred at an alarming rate and most children were at greater risk of being affected. Therefore, cadmium contamination should be taken seriously by the responsible authorities.

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