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A DEEP LEARNING BASED DISCONTINUOUS GALERKIN METHOD FOR HYPERBOLIC EQUATIONS WITH DISCONTINUOUS SOLUTIONS AND RANDOM UNCERTAINTIES

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Journal of Computational Mathematics 2023年第6期41卷 1281-1304页

作者： Jingrun Chen Shi Jin liyao lyu School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China Suzhou Institute for Advanced Research University of Science and Technology of ChinaSuzhou 215123China School of Mathematical Sciences Institute of Natural Sciencesand MOE-LSCShanghai Jiao Tong UniversityShanghai200240China Department of Computational Mathematics Scienceand EngineeringMichigan State UniversityEast LansingMI48824USA

We propose a deep learning based discontinuous Galerkin method(D2GM)to solve hyperbolic equations with discontinuous solutions and random *** main computational challenges for such problems include discontinuities of the solutions and the curse of dimensionality due to *** learning techniques have been favored for high-dimensional problems but face difficulties when the solution is not smooth,thus have so far been mainly used for viscous hyperbolic system that admits only smooth *** alleviate this difficulty by setting up the loss function using discrete shock capturing schemes–the discontinous Galerkin method as an example–since the solutions are smooth in the discrete *** convergence of D2GM is established via the Lax equivalence theorem kind of *** high-dimensional random space is handled by the Monte-Carlo *** a setup makes the D2GM approximate high-dimensional functions over the random space with satisfactory accuracy at reasonable *** D2GM is found numerically to be first-order and second-order accurate for(stochastic)linear conservation law with smooth solutions using piecewise constant and piecewise linear basis functions,*** examples are given to verify the efficiency and the robustness of D2GM with the dimensionality of random variables up to 200 for(stochastic)linear conservation law and(stochastic)Burgers’equation.

关键词： Discontinuous Galerkin method Loss function Convergence analysis Deep learning Hyperbolic equation

A Consensus-Based Global Optimization Method with Adaptive Momentum Estimation

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Communications in Computational Physics 2022年第4期31卷 1296-1316页

作者： Jingrun Chen Shi Jin liyao lyu School of Mathematical Sciences University of Science and Technology of ChinaHefeiAnhui 230026China Suzhou Institute for Advanced Research University of Science and Technology of ChinaSuzhouJiangsu 215123China School of Mathematical Sciences Institute of Natural SciencesMOE-LSCShanghai Jiao Tong UniversityShanghai200240China Department of Computational Mathematics Scienceand EngineeringMichigan State UniversityEast LansingMI48824USA

Objective functions in large-scalemachine-learning and artificial intelligence applications often live in high dimensions with strong non-convexity and massive local ***-based methods,such as the stochastic gradient method and Adam[15],and gradient-freemethods,such as the consensus-based optimization(CBO)method,can be employed to find *** this work,based on the CBO method and Adam,we propose a consensus-based global optimization method with adaptive momentum estimation(Adam-CBO).Advantages of the Adam-CBO method include:It is capable of finding global minima of non-convex objective functions with high success rates and low *** is verified by finding the global minimizer of the 1000 dimensional Rastrigin function with 100%success rate at a cost only growing linearly with respect to the *** can handle non-differentiable activation functions and thus approximate lowregularity functions with better *** is confirmed by solving a machine learning task for partial differential equations with low-regularity solutions where the Adam-CBO method provides better results than *** is robust in the sense that its convergence is insensitive to the learning rate by a linear stability *** is confirmed by finding theminimizer of a quadratic function.

关键词： Consensus-based optimization global optimization machine learning curse of dimensionality

Advances in theoretical calculations of organic thermoelectric materials

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Chinese Chemical Letters 2024年第8期35卷 112-127页

作者： Shaohua Zhang liyao Liu Yingqiao Ma Chong-an Di Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

Organic thermoelectric(OTE)materials and devices have garnered significant attention in the past decade for flexible and wearable *** to the numerous combinations of different backbones,side chains,and functional groups for polymer molecules,further efficient developments of high perfor-mance OTEs rely on reverse and rational molecular design as well as fundamental understanding to the structure-property relationship,which both require precise theoretical ***,many theo-retical efforts and progresses have been made to predict TE properties and develop high performance OTE ***,we present first the general methods and principles for OTE theoretical ***,the latest theoretical advances regarding the effects of molecular design,chemical dop-ing,ambipolar charge transport etc.,to TE conversion are carefully *** theoretical advances not only significantly deepen the fundamental understanding of OTEs,but also provide precise guidance to the molecular design of OTE ***,we propose several perspectives for future theoretical investigations of OTEs.

关键词： Organic thermoelectricity Theoretical study Organic semiconductor Structure-property relation Single-molecular device

Unconfined compressive strength and failure behaviour of completely weathered granite from a fault zone

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Journal of Mountain Science 2024年第6期21卷 2140-2158页

作者： DU Shaohua MA Jinyin MA liyao ZHAO Yaqian School of Civil Engineering and Architecture Henan University of Science and TechnologyLuoyang 471023China School of Resources and Safety Engineering Central South UniversityChangsha 410083China China Railway 18th Bureau Group Co. LtdTianjin 300222 China China General Nuclear Power Corporation Shenzhen 518031China

Understanding the strength characteristics and deformation behaviour of the tunnel surrounding rock in a fault zone is significant for tunnel stability *** this study,a series of unconfined compression tests were conducted to investigate the mechanical characteristics and failure behaviour of completely weathered granite(CWG)from a fault zone,considering with height-diameter(h/d)ratio,dry densities(ρd)and moisture contents(ω).Based on the experimental results,a regression mathematical model of unconfined compressive strength(UCS)for CWG was developed using the Multiple Nonlinear Regression method(MNLR).The research results indicated that the UCS of the specimen with a h/d ratio of 0.6 decreased with the increase ofω.When the h/d ratio increased to 1.0,the UCS increasedωwith up to 10.5%and then ***ρd is conducive to the improvement of the UCS at anyω.The deformation and rupture process as well as final failure modes of the specimen are controlled by h/d ratio,ρd andω,and the h/d ratio is the dominant factor affecting the final failure mode,followed byωandρ*** specimens with different h/d ratio exhibited completely different fracture mode,i.e.,typical splitting failure(h/d=0.6)and shear failure(h/d=1.0).By comparing the experimental results,this regression model for predicting UCS is accurate and reliable,and the h/d ratio is the dominant factor affecting the UCS of CWG,followed byρd and thenω.These findings provide important references for maintenance of the tunnel crossing other fault fractured zones,especially at low confining pressure or unconfined condition.

关键词： Fault fracture zone Completely weathered granite(CWG) Unconfined compression strength(UCS) Multiple nonlinear regression model

Management of triplet excitons transition:fine regulation of Förster and dexter energy transfer simultaneously

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Light(Science & Applications) 2024年第2期13卷 302-315页

作者： Jiaqiang Wang Yujie Yang Xinnan Sun Xiaoning Li liyao Zhang Zhen Li Institute of Molecular Aggregation Science Tianjin UniversityTianjin300072China School of Life Sciences Tianjin UniversityTianjin300072China Hubei Key Lab on Organic and Polymeric Opto-Electronic Materials Department of ChemistryWuhan UniversityWuhan430072China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan430072China Joint School of National University of Singapore Tianjin UniversityInternational Campus of Tianjin UniversityBinhai New CityFuzhou350207China

Understanding and management of triplet excitons transition in the same molecule remain a great ***,for the first time,by host engineering,manageable transitions of triplet excitons in a naphthalimide derivative NDOH were achieved,and monitored through the intensity ratio(ITADF/IRTP)between thermally activated delayed fluorescence(TADF)and room-temperature phosphorescence(RTP).Energy differences between lowest triplet excited states of host and guest were changed from 0.03 to 0.17 eV,and ITADF/IRTP of NDOH decreased by 200 times,thus red shifting the afterglow *** was proposed that shorter conjugation length led to larger band gaps of host materials,thus contributing to efficient Dexter and inefficient Förster energy ***,no transition to singlet state and only strongest RTP with quantum yield of 13.9%could be observed,when PBNC with loosest stacking and largest band gap acted as *** work provides novel insight for the management and prediction of triplet exciton transitions and the development of smart afterglow materials.

关键词： materials transition transitions

Identification of key genes regulating the synthesis of quercetin derivatives in Rosa roxburghii through integrated transcriptomics and metabolomics

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Journal of Integrative Agriculture 2024年第3期23卷 876-887页

作者： liyao Su Min Wu Tian Zhang Yan Zhong Zongming(Max) Cheng State Key Laboratory of Crop Genetics and Germplasm Enhancement College of HorticultureNanjing Agricultural UniversityNanjing210095China

Rosa roxburghii fruit is rich in flavonoids, but little is known about their biosynthetic pathways. In this study, we employed transcriptomics and metabolomics to study changes related to the flavonoids at five different stages of R. roxburghii fruit development. Flavonoids and the genes related to their biosynthesis were found to undergo significant changes in abundance across different developmental stages, and numerous quercetin derivatives were identified. We found three gene expression modules that were significantly associated with the abundances of the different flavonoids in R. roxburghii and identified three structural UDP-glycosyltransferase genes directly involved in the synthesis of quercetin derivatives within these modules. In addition, we found that RrBEH4, RrLBD1 and RrPIF8could significantly increase the expression of downstream quercetin derivative biosynthesis genes. Taken together,these results provide new insights into the metabolism of flavonoids and the accumulation of quercetin derivatives in R. roxburghii.

关键词： Rosa roxburghii quercetin derivatives weighted gene co-expression network analysis transcription factor transcriptome metabolome

Current Status and Perspectives of Dual-Atom Catalysts Towards Sustainable Energy Utilization

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Nano-Micro Letters 2024年第7期16卷 402-440页

作者： Yizhe Li Yajie Li Hao Sun liyao Gao Xiangrong Jin Yaping Li Zhi LV Lijun Xu Wen Liu Xiaoming Sun State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science EngineeringCollege of ChemistryBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China Xinjiang Coal Mine Mechanical and Electrical Engineering Technology Research Center Xinjiang Institute of EngineeringUrumqi 830023Xinjiang Uygur Autonomous RegionPeople’s Republic of China

The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance ***,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of *** to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic *** these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal *** have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active *** this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related *** last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction *** future research challenges and opportunities are also raised in prospective section.

关键词： Dual-atom catalysts Synergetic effect Electrocatalysis Oxygen reduction reaction CO_(2)reduction reaction Hydrogen evolution reaction N2 reduction reaction

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直升机超临界尾轴限幅减振器安装位置研究

航空动力学报 2024年第6期39卷 86-96页

作者：宋立瑶王旦曹鹏陈柏朱如鹏南京航空航天大学直升机传动技术国家级重点实验室南京210016 中国航发湖南动力机械研究所直升机传动技术国家级重点实验室湖南株洲412002

为了使限幅减振器对传动轴跨1阶及2阶临界转速均起到较好的减振作用,研究了限幅减振器安装位置对传动轴与限幅减振器系统非线性动力学的影响。首先基于Timoshenko梁和非线性碰摩理论建立了传动轴与限幅减振器系统的非线性有限元动力学模... 详细信息

为了使限幅减振器对传动轴跨1阶及2阶临界转速均起到较好的减振作用,研究了限幅减振器安装位置对传动轴与限幅减振器系统非线性动力学的影响。首先基于Timoshenko梁和非线性碰摩理论建立了传动轴与限幅减振器系统的非线性有限元动力学模型,通过数值计算得到了系统响应。对传动轴典型跨临界过程及安装位置对减振效果的影响进行了分析。结果表明:一个典型的传动轴跨临界过程可以分为4个阶段,分别为无碰摩、拟周期碰摩、同频全周碰摩,最后回到无碰摩阶段。将减振器安装在中间节点只能有效抑制传动轴跨1阶临界转速的振动,而安装在1/4节点及3/8节点处能同时减弱跨1阶及2阶临界转速的振动,但安装在3/8节点处有可能使传动轴无法正常工作。

关键词：限幅减振器超临界尾轴位置优化碰摩干摩擦

一咏三叹,由景至境——《诗经·国风》中自然景观展现特征及先民审美模式研究

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西部人居环境学刊 2024年第3期39卷 103-108页

作者：谷光灿王丽瑶重庆大学建筑城规学院

《诗经》是我国诗歌史上举足轻重的存在,《国风》正是《诗经》的精华。在《国风》诗中,大量的诗歌涉及到了自然景观,而对于《诗经》的研究大多集中在文史哲领域,立足于风景园林学的相关研究较为匮乏,作为描写风景的最早诗篇尚未被研究... 详细信息

《诗经》是我国诗歌史上举足轻重的存在,《国风》正是《诗经》的精华。在《国风》诗中,大量的诗歌涉及到了自然景观,而对于《诗经》的研究大多集中在文史哲领域,立足于风景园林学的相关研究较为匮乏,作为描写风景的最早诗篇尚未被研究颇为遗憾。因此将其作为研究重点,首先对《国风》中的自然景观要素进行提取、分类,分析其特点,得出其层次性和分时性的展现规律,以此为基础总结出先民既存型、演化型和类比型三种审美模式,即对中国人原生情感中的自然景观的感知方式和审美模式的溯源。寻找中国人对自然景观情感的原始表达,以及遗传意义,以期为现今的风景遗产保护与景观设计提供参考与启示。

关键词：《诗经》国风人居环境自然景观审美模式