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Optimization of Random Feature Method in the high-Precision Regime

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1490-1517页

作者： Jingrun Chen Weinan e Yifei Sun School of Mathematical Sciences and Suzhou Institute for Advanced Research Suzhou 215006JiangsuChina University of Science and Technology of China Hefei 230026AnhuiChina Center for Machine Learning Research and School of Mathematical Sciences Peking UniversityBeijing 100871China AI for Science Institute Beijing 100084China School of Mathematical Sciences Soochow UniversitySuzhou 215006JiangsuChina

Machine learning has been widely used for solving partial differential equations(PDes)in recent years,among which the random feature method(RFM)exhibits spectral accuracy and can compete with traditional solvers in terms of both accuracy and ***,the optimization problem in the RFM is more difficult to solve than those that arise in traditional *** the broader machine-learning research,which frequently targets tasks within the low-precision regime,our study focuses on the high-precision regime crucial for solving *** this work,we study this problem from the following aspects:(i)we analyze the coeffcient matrix that arises in the RFM by studying the distribution of singular values;(ii)we investigate whether the continuous training causes the overfitting issue;(ii)we test direct and iterative methods as well as randomized methods for solving the optimization *** on these results,we find that direct methods are superior to other methods if memory is not an issue,while iterative methods typically have low accuracy and can be improved by preconditioning to some extent.

关键词： Random feature method(RFM) Partial differential equation(PDe) Least-squares problem Direct method Iterative method

Discrete Boltzmann model with split collision for nonequilibrium reactive flows

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Communications in Theoretical Physics 2024年第8期76卷 164-186页

作者： Chuandong Lin Kai h Luo huilin Lai Sino-French Institute of Nuclear engineering and Technology Sun Yat-sen UniversityZhuhai 519082China Key Laboratory for Thermal Science and Power engineering of Ministry of education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Department of Mechanical engineering National University of Singapore10 Kent Ridge Crescent119260Singapore Department of Mechanical engineering University College LondonTorrington PlaceLondon WC1E 7JEUnited Kingdom School of Mathematics and Statistics Key Laboratory of Analytical Mathematics and Applications(Ministry of Education)Fujian Key Laboratory of Analytical Mathematics and Applications(FJKLAMA)Center for Applied Mathematics of Fujian Province(FJNU)Fujian Normal University350117 FuzhouChina

A multi-relaxation-time discrete Boltzmann model(DBM) with split collision is proposed for both subsonic and supersonic compressible reacting flows, where chemical reactions take place among various components. The physical model is based on a unified set of discrete Boltzmann equations that describes the evolution of each chemical species with adjustable acceleration, specific heat ratio, and Prandtl number. On the right-hand side of discrete Boltzmann equations, the collision,force, and reaction terms denote the change rates of distribution functions due to self-and crosscollisions, external forces, and chemical reactions, respectively. The source terms can be calculated in three ways, among which the matrix inversion method possesses the highest physical accuracy and computational efficiency. Through Chapman-enskog analysis, it is proved that the DBM is consistent with the reactive Navier-Stokes equations, Fick's law and the Stefan-Maxwell diffusion equation in the hydrodynamic limit. Compared with the one-step-relaxation model, the split collision model offers a detailed and precise description of hydrodynamic, thermodynamic, and chemical nonequilibrium effects. Finally, the model is validated by six benchmarks, including multicomponent diffusion, mixture in the force field, Kelvin-helmholtz instability, flame at constant pressure, opposing chemical reaction, and steady detonation.

关键词： discrete Boltzmann method reactive flow detonation nonequilibrium effect

Olfactory immune response to SARS-CoV-2

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Cellular & Molecular Immunology 2024年第2期21卷 134-143页

作者： Sebastian A.Wellford e.Ashley Moseman Department of Integrative Immunobiology Duke University School of MedicineDurhamNCUSA

Numerous pathogens can infect the olfactory tract,yet the pandemic caused by SARS-CoV-2 has strongly emphasized the importance of the olfactory mucosa as an immune *** in the nasal passages,the olfactory mucosa is directly exposed to the environment to sense airborne odorants;however,this also means it can serve as a direct route of entry from the outside world into the *** a result,olfactotropic infections can have serious consequences,including dysfunction of the olfactory system,CNS invasion,dissemination to the lower respiratory tract,and transmission between *** research has shown that a distinctive immune response is needed to protect this neuronal and mucosal tissue.A better understanding of innate,adaptive,and structural immune barriers in the olfactory mucosa is needed to develop effective therapeutics and vaccines against olfactotropic microbes such as ***,we summarize the ramifications of SARS-CoV-2 infection of the olfactory mucosa,review the subsequent immune response,and discuss important areas of future research for olfactory immunity to infectious disease.

关键词： Mucosal immunology Neuroimmunology Infectious Disease Sars-CoV-2

hepatitis B virus genotypes in precision medicine of hepatitis Brelated hepatocellular carcinoma:Where we are now

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1097-1103页

作者： Caecilia h C Sukowati Sri Jayanti Turyadi Turyadi David h Muljono Claudio Tiribelli eijkman Research Center for Molecular Biology Research Organization for HealthNational Research and Innovation Agency of IndonesiaJakarta 10340Indonesia Liver Cancer Unit Fondazione Italiana Fegato ONLUSTrieste 34149Italy Faculty of Medicine Hasanuddin UniversityMakassar 90245South SulawesiIndonesia Faculty of Medicine and health University of SydneySydney 2050Australia

hepatitis B virus(hBV)infection is a major player in chronic hepatitis B that may lead to the development of hepatocellular carcinoma(hCC).hBV genetics are diverse where it is classified into at least 9 genotypes(A to I)and 1 putative genotype(J),each with specific geographical distribution and possible different clinical outcomes in the *** diversity may be associated with the precision medicine for hBV-related hCC and the success of therapeutical approaches against hCC,related to different pathogenicity of the virus and host *** editorial discusses recent updates on whether the classification of hBV genetic diversity is still valid in terms of viral oncogenicity to the hCC and its precision medicine,in addition to the recent advances in cellular and molecular biology technologies.

关键词： hepatitis B virus hepatocellular carcinoma Genotypes Pathogenesis Precision medicine

Fish-on-Chips:unveiling neural processing of chemicals in small animals through precise fluidic control

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Neural Regeneration Research 2024年第11期19卷 2351-2353页

作者： Samuel K.h.Sy ho Ko Division of Neurology Department of Medicine and TherapeuticsFaculty of MedicineThe Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina Li Ka Shing Institute of health Sciences Faculty of MedicineThe Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina Department of electrical and electronic engineering Faculty of EngineeringThe University of Hong KongPok Fu LamHong Kong IslandHong Kong Special Administrative RegionChina Advanced Biomedical Instrumentation Center Hong Kong Science ParkPak Shek KokNew TerritoriesHong Kong Special Administrative RegionChina Margaret K.L.Cheung Research Center for Management of Parkinsonism Faculty of MedicineThe Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina Lau Tat-chuen Research Center of Brain Degenerative Diseases in Chinese Faculty of MedicineThe Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina Gerald Choa Neuroscience Institute The Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina

Precise chemical cue presentation alongside advanced brainwide imaging techniques is important to the study of chemosensory processing in ***,the dynamic nature of chemical-carrying media,such as water or air,poses a significant challenge for delivering highly-controlled chemical flow to an animal ***,contact-based cue manipulation and delivery easily shift the position of the animal subject,which is often undesirable for high-quality brain ***,more advanced interfacing tools that align with the diverse range of body part sizes of an animal,ranging from micrometer-scale neurons to meter-long limbs,are much *** is particularly crucial when dealing with dimensions that are beyond the reach of conventional experimental tools.

关键词： dealing precise sizes

Selective catalytic reduction of NO by Nh3 on cerium modified faujasite zeolite prepared from aluminum scraps and industrial metasilicate

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Journal of Rare earths 2020年第3期38卷 250-256页

作者： rahma Abid Gerard Delahay hassib Tounsi Laboratory of Advanced Materials National School of Engineers of SfaxUniversity of SfaxTunisia Institut Charles Gerhardt ENSCM"Advanced Materials for Health and Catalysis"240 Av Professor Emile Jeanbrau34296 MontpellierFrance

This work was devoted to the study of the selective catalytic reduction of NO by Nh3 on calcined and hydrothermal treated cerium loaded zeolite *** parent faujasite zeolite Na-F(Si/Al=1.32 and SBeT=749 m^2/g) used as support for the preparation of the catalysts was obtained from industrial sodium metasilicate and aluminum *** expected,the NO conversion increases with increasing the percentage of cerium in the structure of the faujasite *** NO conversion into N2 is reached at 400℃at a space velocity of 250 000 h^-*** high conversion is due to the redox shift between Ce^3+/Ce^4+and the strong acid sites related to the rare earth present in the framework that is the key in SCR of NO ***,the highest loaded cerium catalyst retains almost its activity after hydrothermal treatment at 850℃.This higher loading is desirable for both activity and stability provided that two stages of preparation are used to put the Ce ions in the sodalite cages.

关键词： Aluminum scraps Ce-Y Nh3-SCR hydrothermal stability

Formadinium Cation Doping Stabilized Ultra-deep-blue Lead halide Perovskite Nanocrystal Light-emitting Diodes

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Chemical Research in Chinese Universities 2024年第3期40卷 556-560页

作者： Pui Kei KO Jonathan e.hALPeRT Department of Chemistry The Hong Kong University of Science and TechnologyKowloonHong Kong 999077P.R.China

The halide migration effect in mixed-halide lead-based perovskite is a serious problem hindering the development of its display *** this study,we have successfully addressed this issue by reporting formadinium(FA)doped mixed-halide perovskite nanocrystals(NCs)with ultra-deep-blue emission of 450 nm,narrow bandwidth of 16 nm,and a high photoluminescence quantum yield(PLQY)of 66%.The perovskite nanocrystal light-emitting diodes(NC-LeDs)using this nanocrystal as an active layer achieved a maximum external quantum efficiency(eQe)of 0.32%,30-fold improved compared to that of pristine and stable electroluminescence(eL)spectra at 450 nm under a 4.9–8.0 V *** findings demonstrate the potential of our approach in developing stable and efficient deep blue perovskite NC-LeDs.

关键词： halide perovskite Light-emitting diode Deep-blue

增材制造Ti6Al4V合金的闪速等离子体电解氧化与在生理介质中的电化学行为

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Transactions of Nonferrous Metals Society of China 2024年第4期34卷 1150-1166页

作者： h.MORA-SANCheZ C.RAMOS M.MOheDANO B.TORReS R.ARRABAL e.MATYKINA Departamento de Ingeniería Química y de Materiales Facultad de Ciencias QuímicasUniversidad Complutense de Madrid28040 MadridSpain CIDeTeC Basque Research and Technology Alliance(BRTA)Po.Miramón 19620014 Donostia-San SebastiánSpain Departamento Matemática Aplicada Ciencia e Ingeniería de Materiales y Tecnología ElectrónicaUniversidad Rey Juan CarlosC/Tulipán s/nMóstoles 28933MadridSpain

研究激光粉末床熔融增材制造(AM)(又称直接金属激光烧结)技术制备的Ti6Al4V合金等离子体电解氧化(PeO)处理及其电化学行为。通过短时间(<120 s)PeO处理(也称闪速PeO),在AM合金和传统合金表面制备了3~10μm厚、含Ca和P的涂层。然后在改... 详细信息

研究激光粉末床熔融增材制造(AM)(又称直接金属激光烧结)技术制备的Ti6Al4V合金等离子体电解氧化(PeO)处理及其电化学行为。通过短时间(eO处理(也称闪速PeO),在AM合金和传统合金表面制备了3~10μm厚、含Ca和P的涂层。然后在改良的α-MeM溶液中,通过动电位极化曲线和电化学阻抗谱(eIS)评估了合金的电化学行为。与传统合金相比,AM合金中形成了细小的层片状α显微组织和层间小尺寸的β相颗粒,这促使了火花的产生,从而促进了PeO涂层的生长。闪速PeO涂层提高了传统合金和AM合金的耐腐蚀性,最薄的涂层(eO处理也足以成功避免这种情况。

关键词：增材制造激光粉末床熔融等离子体电解氧化闪速PeO 钛缝隙腐蚀 α-MeM

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Function and dysfunction of GeMIN5:understanding a novel neurodevelopmental disorder

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Neural Regeneration Research 2024年第11期19卷 2377-2386页

作者： Charles h.Nelson Udai B.Pandey Department of Pediatrics Division of Child NeurologyChildren’s Hospital of PittsburghUniversity of Pittsburgh Medical CenterPittsburghPAUSA Children’s Neuroscience Institute Children’s Hospital of PittsburghUniversity of Pittsburgh Medical CenterPittsburghPAUSA

The recent identification of a neurodevelopmental disorder with cerebellar atrophy and motor dysfunction(NeDCAM)has resulted in an increased interest in GeMIN5,a multifunction RNA-binding *** the largest member of the survival motor neuron complex,GeMIN5 plays a key role in the biogenesis of small nuclear ribonucleoproteins while also exhibiting translational regulatory functions as an independent *** many questions remain regarding both the pathogenesis and pathophysiology of this new disorder,considerable progress has been made in the brief time since its *** this review,we examine GeMIN5 within the context of NeDCAM,focusing on the structure,function,and expression of the protein specifically in regard to the disorder ***,we explore the current animal models of NeDCAM,as well as potential molecular pathways for treatment and future directions of *** review provides a comprehensive overview of recent advances in our understanding of this unique member of the survival motor neuron complex.

关键词： cerebellar atrophy GeMIN5 neurodevelopmental disorder neurological disease SMN complex