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Communications on Applied Mathematics and Computation 2024年第2期6卷 811-836页

作者： Michael Franco per-Olof persson Will Pazner Department of Mathematics University of CaliforniaBerkeleyBerkeleyCA 94720-3840USA Fariborz Maseeh Department of Mathematics and Statistics Portland State UniversityPortlandOR 97201USA

We present a class of preconditioners for the linear systems resulting from a finite element or discontinuous Galerkin discretizations of advection-dominated *** preconditioners are designed to treat the case of geometrically localized stiffness,where the convergence rates of iterative methods are degraded in a localized subregion of the *** convergence may be caused by a number of factors,including the mesh size,anisotropy,highly variable coefficients,and more challenging *** approach taken in this work is to correct well-known preconditioners such as the block Jacobi and the block incomplete LU(ILU)with an adaptive inner subregion *** goal of these preconditioners is to reduce the number of costly global iterations by accelerating the convergence in the stiff region by iterating on the less expensive reduced *** tolerance for the inner iteration is adaptively chosen to minimize subregion-local work while guaranteeing global convergence *** present analysis showing that the convergence of these preconditioners,even when combined with an adaptively selected tolerance,is independent of discretization parameters(e.g.,the mesh size and diffusion coefficient)in the *** demonstrate significant performance improvements over black-box preconditioners when applied to several model convection-diffusion ***,we present performance results of several variations of iterative subregion correction preconditioners applied to the Reynolds number 2.25×10^(6)fluid flow over the NACA 0012 airfoil,as well as massively separated flow at 30°angle of attack.

关键词： Subregion correction Nested Krylov Geometrically localized stiffness

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科学中心的未来

科学中心的未来

Colorless-to-colorful switching of electrochromic MXene by reversible ion insertion

中国自然科学博物馆协会二十五周年暨国际学术报告会

作者： per-edvin persson 芬兰科学中心

全球共有一千五百余个科学中心,这个领域还在壮大。科学中心是对正规教育系统的补充,也是终生教育的组成部分。科学中心正在拓宽途径,从全部的“动手型”到采用多种手段。该领域正聚焦“动脑型”手段。拓宽的媒体包括展厅内有历史意义...

全球共有一千五百余个科学中心,这个领域还在壮大。科学中心是对正规教育系统的补充,也是终生教育的组成部分。科学中心正在拓宽途径,从全部的“动手型”到采用多种手段。该领域正聚焦“动脑型”手段。拓宽的媒体包括展厅内有历史意义的人工制品、多媒体和模型,还包括覆盖整个博物馆的讲座、研讨会、专题小组讨论会和主题活动。目前,网络被用于操作系统,它是对展品的补充,对科学中心的活动在网上作说明。现实世界与虚拟世界之间的综合将会不断增强。科学中心的展示会随着时间的推移而变化,但是,在未来较长一段时间内,科学博物馆仍将是人们聚会和访问的地方。参观科学中心是一种社会活动,该活动包括与现实世界的互动,这种互动目前在网络上是无法实现的。

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Nano Research 2022年第4期15卷 3587-3593页

作者： Jianxia Jiang Leiqiang Qin Joseph Halim per O.Å.persson Lintao Hou Johanna Rosen Guangzhou Key Laboratory of Vacuum Coating Technologies and New Energy Materials Physics DepartmentJinan UniversityGuangzhou 510632China Department of Physics Chemistry and Biology(IFM)Linköping UniversityLinköping SE-58183Sweden

Electrochromic(EC)materials that change color with voltage have been widely studied for use in dynamic ***,colorless-to-colorful switching with high contrast ratio is generically unattainable,especially for colorless-to-black electrochromic materials with an ultrahigh contrast ratio over the entire visible *** this work,we developed Nb_(1.33)C MXene-based dynamic windows with colorless-to-black switching of up to 75%reversible change in transmittance from 300 to 1,500 *** exploring the electrochromic effects of different electrolytes through in situ optical changes and electrochemical quartz crystal microbalance(EQCM),it is found that electrochromic behavior is greatly influenced by the extent of reversible Li^(+)insertion/deinsertion between the two-dimensional Nb_(1.33)C MXene *** addition,a colorless-to-black EC device based on Nb_(1.33)C with an overall integrated contrast ratio over 80%was successfully constructed by a solution-processable spin coating *** work enables a simple route to fabricate MXene-based high-performance electrochromic smart windows,which is important for further expanding the application of MXenes to optoelectronic and photonic applications.

关键词： MXenes electrochromic materials colorless-to-black switching high contrast ratio reversible Li^(+)insertion

MXene-based symmetric supercapacitors with high voltage and high energy density

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Materials Reports(Energy) 2022年第1期2卷 105-111页

作者： Wei Zheng Joseph Halim per O.Å.persson Johanna Rosen Michel W.Barsoum Department of Physics Chemistry and Biology(IFM)Linkoping University58183LinkopingSweden Department of Materials Science and Engineering Drexel University19104PhiladelphiaPAUSA

MXene-based aqueous symmetric supercapacitors(SSCs)are attractive due to their good rate performances and green ***,it remains a challenge to reach voltages much over 1.2 V,which significantly diminishes their energy ***,we report on Mo_(1.33)CTz MXene-based SSCs possessing high voltages in a 19.5 M LiCl *** from the vacancy-rich structure and high stable potential window of Mo_(1.33)CTz,the obtained SSCs deliver a maximum energy density of>38.2 mWh cm^(-3) at a power density of 196.6 mW cm^(-3) under an operating voltage of 1.4 V,along with excellent rate performance and impressive cycling *** highly concentrated LiCl electrolyte is also applicable to Ti_(3)C_(2)Tz,the most widely studied MXene,achieving a maximum energy density of>41.3 mWh cm^(-3) at a power density of 165.2 mW cm^(-3) with an operating voltage of 1.8 *** drop in energy density with increasing power in the Ti_(3)C_(2)Tz cells was steeper than for the Mo-based *** work provides a roadmap to develop superior SSCs with high voltages and high energy densities.

关键词： MXene Symmetric supercapacitor High voltage High energy density Highly concentrated electrolyte

基于A位元素置换策略合成新型MAX相材料Ti_3ZnC_2

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无机材料学报 2019年第1期34卷 60-64页

作者：李勉李友兵罗侃 LU Jun EKLUND per persson per ROSEN Johanna HULTMAN Lars 都时禹黄政仁黄庆中国科学院宁波工业技术与工程研究所核能材料工程实验室(筹) 宁波315201 Department of Physics Chemistry and Biology (IFM) Link?ping University

MAX相材料是一类兼具金属和陶瓷特性的三元层状材料,在高温导电、耐磨、耐腐蚀和耐辐照损伤等方面性能优异。目前已经合成出的MAX相材料已有70余种,但A位元素一直局限在ⅢA和ⅣA主族元素,如Al、Si、Ga等,而以副族元素占据A位的MAX相鲜... 详细信息

MAX相材料是一类兼具金属和陶瓷特性的三元层状材料,在高温导电、耐磨、耐腐蚀和耐辐照损伤等方面性能优异。目前已经合成出的MAX相材料已有70余种,但A位元素一直局限在ⅢA和ⅣA主族元素,如Al、Si、Ga等,而以副族元素占据A位的MAX相鲜有报道。本研究以Ti_3AlC_2为前驱体,利用熔盐中的A位置换反应,制备出了A位为Zn元素的全新MAX相材料Ti_3ZnC_2。结合X射线衍射、扫描电子显微镜和透射电子显微镜等分析手段对Ti_3ZnC_2的成分和结构进行了确认,并通过密度泛函理论对Ti_3ZnC_2的结构稳定性和晶格参数进行了确定。进一步通过热力学计算对Fe、Co、Ni、Cu等几种元素的A位置换反应进行了预测,发现采用这几种元素的氧化物进行置换反应在热力学上也都具有可行性。本研究所提出的元素置换策略是在保持MAX相六方层状晶体结构的基础上,利用Al、Zn在高温下形成共晶产物实现Zn原子向A层内的迁移,而熔盐介质的存在促进了反应动力学。本方法巧妙地避免了MAX相传统合成过程中竞争相的形成,如M-A合金相,因此可以用于探索更多未知的MAX相材料。

关键词： MAX相置换反应 Ti3ZnC2

Electrochemical Lithium Storage performance of Molten Salt Derived V_(2)SnC MAX Phase

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Nano-Micro Letters 2021年第10期13卷 266-275页

作者： Youbing Li Guoliang Ma Hui Shao Peng Xiao Jun Lu Jin Xu Jinrong Hou Ke Chen Xiao Zhang Mian Li per OÅpersson Lars Hultman per Eklund Shiyu Du Zhifang Chai Zhengren Huang Na Jin Jiwei Ma Ying Liu Zifeng Lin Qing Huang Engineering Laboratory of Advanced Energy Materials Ningbo Institute of Industrial TechnologyChinese Academy of SciencesNingbo 315201ZhejiangPeople’s Republic of China Qianwan Institute of CNiTECH Ningbo 315336People’s Republic of China College of Materials Science and Engineering Sichuan UniversityChengdu 610065People’s Republic of China CIRIMAT UMR CNRS 5085 UniversitéToulouse III-Paul Sabatier118 route de Narbonne31062 Toulouse Cedex 9France Department of Physics Chemistry and Biology(IFM)Linköping University58183 LinköpingSweden School of Machine Engineering Dongguan University of TechnologyDongguan 523808People’s Republic of China Institute of New Energy for Vehicles School of Materials Science and EngineeringTongji UniversityShanghai 201804People’s Republic of China

MAX phases are gaining attention as precursors of two-dimensional MXenes that are intensively pursued in applications for electrochemical energy ***,we report the preparation of V_(2)SnC MAX phase by the molten salt method.V_(2)SnC is investigated as a lithium storage anode,showing a high gravimetric capacity of 490 mAh g−1 and volumetric capacity of 570 mAh cm^(−3) as well as superior rate performance of 95 mAh g^(−1)(110 mAh cm^(−3))at 50 C,surpassing the ever-reported performance of MAX phase ***-ported by operando X-ray diffraction and density functional theory,a charge storage mechanism with dual redox reaction is proposed with a Sn-Li(de)alloying reaction that occurs at the edge sites of V_(2)SnC particles where Sn atoms are exposed to the electrolyte followed by a redox reaction that occurs at V_(2)C layers with *** study offers promise of using MAX phases with M-site and A-site elements that are redox active as high-rate lithium storage materials.

关键词： MAX phase Molten salt Lithium storage High-rate Energy storage

Single Cr atom catalytic growth of graphene

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Nano Research 2018年第5期11卷 2405-2411页

作者： Huy Q. Ta Uang Zhao Wanjian Yin Darius Pohl Bemd Rellinghaus Thomas Gemming Barbara Trzebicka Justinas Palisaitis Gao Jing per O. A. persson Zhongfan Liu Alicja Bachmatiuk Mark H. Rummeli Soochow Institute for Energy and Materials Innovations College of Physics Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University Suzhou 215005 China Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province Soochow University Suzhou 215006 China Centre of Polymer and Carbon Materials Polish Academy of Sciences M. Curie-Sklodowskiej 34 Zabrze 41-819 Poland IFW Dresden Helmholtz Strasse 20 01069 Dresden Germany Department of Physics Chemistry and Biology (IFM) Linkoping University SE-581 83 Linkoping Sweden Center for Nanochemistry Beijing Science and Engineering Centre for Nanocarbons Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

Single atoms are the ultimate minimum size limit for catalysts. Graphene, as an exciting, ultimately thin （one atom thick） material can be imaged in a transmission electron microscope with relatively few imaging artefacts. Here, we directly observe the behavior of single Cr atoms in graphene mono- and di-vacancies and, more importantly, at graphene edges. Similar studies at graphene edges with other elemental atoms, with the exception of Fe, show catalytic etching of graphene. Fe atoms have been shown to both etch and grow graphene. In contrast, Cr atoms are only observed to induce graphene growth. Complementary theoretical calculations illuminate the differences between Fe and Cr, and confirm single Cr atoms as superior catalysts for sp^2 carbon growth.

关键词： in situ transmission electron microscope (TEM) electron driven catalysis Cr single atom graphene synthesis

A Dual-Promoter Gene Orchestrates the Sucrose-Coordinated Synthesis of Starch and Fructan in Barley

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Molecular Plant 2017年第12期10卷 1556-1570页

作者： Yunkai Jin Mingliang Fei Sara Rosenquist Lu Jin Suresh Gohil Corine Sandstrom Helena Olsson Cecilia persson Anna-Stina Hoglund Gunnel Fransson Ying Ruan per Aman Christer Jansson Chunlin Liu Roger Andersson Chuanxin Sun Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization Hunan Agricultural University Changsha 410128 China Department of Plant Biology Uppsala BioCenter Linnean Centre for Plant Biology Swedish University of Agricultural Sciences P.O. Box 7080 75007 UppsalaSweden Key Laboratory of Education Department of Hunan Province on Plant Genetics and Molecular Biology College of Bioscience and BiotechnologyHunan Agricultural University Changsha 410128 China Department of Chemistry and Biotechnology Uppsala BioCenter Swedish University of Agrioultural Scienoes P.O. Box 7015 75007 Uppsala Sweden The Swedish NMR Centre at University of Gothenburg Box 465 405 30 Gothenburg Sweden Department of Molecular Sciences Uppsala BioCenter Swedish University of Agricultural Sciences P.O. Box 7051 750 07 Uppsala Sweden The Environmental Molecular Sciences Laboratory (EMSL) Pacific Northwest National Laboratory P.O. Box 999 K8-93 Richland WA 99352 USA These authors contributed equally to this article.

Sequential carbohydrate synthesis is important for plant survival because it guarantees energy supplies for growth and development during plant ontogeny and reproduction. Starch and fructan are two important carbohydrates in many flowering plants and in human diets. Understanding this coordinated starch and fructan synthesis and unraveling how plants allocate photosynthates and prioritize different carbohydrate synthesis for survival could lead to improvements to cereals in agriculture for the purposes of greater food security and production quality. Here, we report a system from a single gene in barley employing two alternative promoters, one intronic/exonic, to generate two sequence-overlapping but functionally opposing transcription factors, in sensing sucrose, potentially via sucrose/gluco lose 6-phosphate signaling. The system employs an autoregulatory mechanism in perceiving a sucrose- controlled trans activity on one promoter and orchestrating the coordinated starch and fructan synthesis by competitive transcription factor binding on the other promoter. As a case in point for the physiological roles of the system, we have demonstrated that this multitasking system can be exploited in breeding barley with tailored amounts of fructan to produce healthy food ingredients. The identification of an intron/exon-spanning promoter in a hosting gene, resulting in proteins with distinct functions, adds to the complexity of plant genomes.

关键词： ANTISENSE OLIGODEOXYNUCLEOTIDE INHIBITION VACUOLAR INVERTASE GENE LOLIUM-perENNE L ARABIDOPSIS-THALIANA TRANSCRIPTION FACTOR TREHALOSE 6-PHOSPHATE NICOTIANA-BENTHAMIANA PLANT BIOLOGY LEAF SHEATHS METABOLISM

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精心设计隧道周边眼的排列以防岩石破坏

有色金属工程 1982年第2期 13-18页

作者： Roger Holmberg,per-Anders persson,宗海祥瑞典爆轰研究基金会瑞典爆轰研究基金会

本文叙述了一种用以确定岩石最小破坏范围时所需的每米炮孔装药量的方法。爆破引起的地面质点的震速,是附近建筑物破坏程度的一种尺度。已经建立了一个表明质点震速是质点至药包的距离和线装药密度的函数的数学模型。该模型与正好在出... 详细信息

本文叙述了一种用以确定岩石最小破坏范围时所需的每米炮孔装药量的方法。爆破引起的地面质点的震速,是附近建筑物破坏程度的一种尺度。已经建立了一个表明质点震速是质点至药包的距离和线装药密度的函数的数学模型。该模型与正好在出现岩石损坏或破碎的细长药包附近的致密岩石中的实验质点震速完全吻合。如果已知炸药的重量威力,则利用这个模型就能估算岩石中由爆破引起的永久变形带或破坏带.这个模型还可用来精确地确定靠近隧道周边的每排孔的最大装药量,可避免在与光面爆破孔相邻的那排孔中使用过多的炸药,因而使最终的隧道顶板更安全,并可降低喷浆支护费用。

关键词：炮孔线装药密度质点震速每米重量威力炮眼岩石破坏周边爆破轮廓爆破药包破坏带装药量