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Analysis of a class of globally divergence-free HDG methods for stationary Navier-Stokes equations

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Science China Mathematics 2024年第5期67卷 1133-1158页

作者： gang Chen Xiaoping Xie School of Mathematics Sichuan University Chengdu 610064China

In this paper,we analyze a class of globally divergence-free(and therefore pressure-robust)hybridizable discontinuous Galerkin(HDG)finite element methods for stationary Navier-Stokes *** methods use the P_(k)/P_(k-1)(k≥1)discontinuous finite element combination for the velocity and pressure approximations in the interior of elements,piecewise Pm(m=k,k-1)for the velocity gradient approximation in the interior of elements,and piecewise P_(k)/P_(k) for the trace approximations of the velocity and pressure on the inter-element *** show that the uniqueness condition for the discrete solution is guaranteed by that for the continuous solution together with a sufficiently small mesh *** on the derived discrete HDG Sobolev embedding properties,optimal error estimates are *** experiments are performed to verify the theoretical analysis.

关键词： Navier-Stokes equations HDG methods divergence-free uniqueness condition error estimates

Overexpression of the transcription factor MdWRKY115 improves drought and osmotic stress tolerance by directly binding to the MdRD22 promoter in apple

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Horticultural Plant Journal 2024年第3期10卷 629-640页

作者： Qinglong Dong Yi Tian Xuemei Zhang Dingyue Duan he Zhang Kaiyu Yang Peng Jia Haoan Luan Suping Guo Guohui Qi Ke mao Fengwang Ma College of Forestry Hebei Agricultural UniversityBaodingHebei 071001China National Engineering Research Center for Agriculture in Northern Mountainous Areas Agricultural Technology Innovation Center in Mountainous Areas of Hebei ProvinceHebei Agricultural UniversityBaodingHebei 071001China State Key Laboratory of Crop Stress Biology for Arid Areas Shaanxi Key Laboratory of AppleCollege of HorticultureNorthwest A&F UniversityYanglingShaanxi 712100China College of Horticulture Hebei Agricultural UniversityBaodingHebei 071001China

Abiotic stress reduces plant yield and *** transcription factors play key roles in abiotic stress responses in plants,but the molecular mechanisms by which WRKY transcription factors mediate responses to drought and osmotic stresses in apple(Malus×domestica Borkh.)remain ***,we functionally characterized the apple GroupⅢWRKY gene ***-PCR analysis showed that MdWRKY115 expression was up-regulated by drought and osmotic *** activity analysis revealed that the promoter activity of MdWRKY115 was enhanced under osmotic *** localization and transactivation assays indicated that MdWRKY115 was localized to the nucleus and had a transcriptional activity domain at the N-terminal *** analysis revealed that the overexpression of MdWRKY115 in Arabidopsis plants and in apple callus markedly enhanced their tolerance to drought and osmotic *** affinity purification sequencing showed that MdWRKY115 binds to the promoter of the stress-related gene *** binding was further verified by an electrophoretic mobility shift ***,these findings suggest that MdWRKY115 is an important regulator of osmotic and drought stress tolerance in apple.

关键词： Apple MdWRKY115 Osmotic stress Drought stress Function analysis

Emerging materials and transistors for integrated circuits

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National Science Review 2024年第3期11卷 7-8页

作者： Ming Liu Lian-mao Peng Lab of Nanofabrication and Novel Device Integration Institute of Microelectronics Chinese Academy of Sciences Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics School of Electronics Peking University

The device technology for integrated circuits(ICs) has received a great deal of attention in the past decade since the mainstream silicon-based complementary metal-oxide-semiconductor(CMOS) field-effect transistor(FET) for modern ICs had been encountering development bottlenecks due to the combination of power constraints, physics, cost and fabrication processes.

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Method for determining the position of landslide slip-surface with a typical inclinometric curves

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Journal of Mountain Science 2024年第2期21卷 413-432页

作者： CheN Hao WU Hong-gang Ocean College Zhejiang UniversityZhoushan 316000China China Northwest Research Institute Co.Ltd.of CREC Lanzhou 730070China

In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily based on abrupt changes observed in the inclinometric *** conventional identification methods,inclinometric curves exhibiting indications of sliding can be categorized into three types:B-type,D-type,and *** position of the slip surface is typically determined by identifying the depth corresponding to the point of maximum displacement ***,this method is sensitive to the interval of measurement points and the observation scale of the coordinate axes and suffers from unclear sliding surfaces and uncertain *** on the variation characteristics of these diagonal curves,we classified the landslide into three components:the sliding body,the sliding interval,and the immobile ***,three different generalization models were established to analyze the relationships between the curve form and the slip surface location based on different physical indicators such as displacement rate,relative displacement,and *** results show that the displacement rate curves of an r-type slope exhibit a clustering feature in the sliding interval,and by solving for the depth of discrete points within the step phase,it is possible to determine the location of the slip *** the other hand,D-type slopes have inflection points in the relative displacement curve located at the slip *** acceleration curves of B-type slopes exhibit clustering characteristics during the sliding interval,while the scattered acceleration data demonstrate wandering ***,the slip surface location can be revealed by solving the depth corresponding to the maximum acceleration with cubic spline *** approach proposed in this paper was applied to the monitoring data of a landslide in Yunnan Province,*** results indicate that our approach can accurately identify the slip surface location and enable computability of its po

关键词： Inclinometric curve Slip-surface position Displacement rate Relative displacement Acceleration

Dynamic steric confinement effect expands the frontier of Cu-catalyzed asymmetric propargylic aminations

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Science China Chemistry 2024年第10期67卷 3181-3183页

作者： Peng Chen mao-mao Zhang Wen-Jing Xiao Liang-Qiu Lu Engineering Research Center of Photoenergy Utilization for Pollution Control and Carbon Reduction Ministry of EducationCollege of ChemistryCentral China Normal University Wuhan Institute of Photochemistry and Technology State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics (LICP)Chinese Academy of Sciences School of Chemistry and Chemical Engineering Henan Normal University

Chiral α-tertiary amines and related azacycles are commonly found in many natural products, pharmaceuticals and agrochemicals [1]. Copper-catalyzed asymmetric propargylic amination(APA) reactions have been established as a reliable method to access enantio-enriched propargylic amines,largely due to the seminal contribution of Nishibayashi et al.[2] and van Maarseveen et al. [3] in 2008.

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Hardware-oriented algorithms for softmax and layer normalization of large language models

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Science China(Information Sciences) 2024年

作者： Wenjie LI Dongxu LYU gang WANG Aokun HU Ningyi XU Guanghui he School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Department of Micro/Nano Electronics Shanghai Jiao Tong University MoE Key Laboratory of Artificial Intelligence Shanghai Jiao Tong University

While large language models (LLMs) have sparked a new revolution in the field of natural language processing (NLP), their hardware accelerators have garnered tremendous attention. However, softmax and layer normalization which are the most common non-linear operations in LLMs are frequently *** paper presents hardware-oriented algorithms for both softmax and layer normalization of LLMs. We propose an approximate approach to implementing division in softmax and extend it for simultaneously computing square root and performing division in layer normalization. It replaces the original computation by multiplication and shifting. For softmax, we further approximate the exponential function by truncating its exponent and then reuse the involved subtraction. For layer normalization, we additionally simplify the computation of denominator by directly removing the term regarding the square of the mean. Furthermore,hardware architectures are developed for the proposed algorithms of softmax and layer normalization. They can work as plug-and-play units for LLM accelerators, requiring no fine-tuning and introducing negligible performance loss. Compared with the state-of-the-art designs, the proposed softmax architecture can save up to 23.45%area cost and 17.39%power consumption, while the proposed layer normalization architecture can save up to 32.70%area cost and 14.29%power consumption.

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BSEC Method for Unveiling Open Clusters and its Application to Gaia DR3:83 New Clusters

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Research in Astronomy and Astrophysics 2024年第5期24卷 169-184页

作者： Zhong-Mu Li Cai-Yan mao Institute of Astronomy and Information Dali UniversityDali 671003China

Open clusters(OCs) are common in the Milky Way, but most of them remain undiscovered. There are numerous techniques, including some machine-learning algorithms, available for the exploration of OCs. However, each method has its limitations and therefore, different approaches to discovering OCs hold significant values. We develop a comprehensive approach method to automatically explore the data space and identify potential OC candidates with relatively reliable membership determination. This approach combines the techniques of Hierarchical Density-Based Spatial Clustering of Applications with Noise, Gaussian mixture model, and a novel cluster member identification technique, color excess constraint. The new method exhibits efficiency in detecting OCs while ensuring precise determination of cluster memberships. Because the main feature of this technique is to add an extra constraint(EC) for the members of cluster candidates using the homogeneity of color excess,compared to typical blind search codes, it is called Blind Search-Extra Constraint(BSEC) method. It is successfully applied to the Gaia Data Release 3, and 83 new OCs are found, whose color–magnitude diagrams(CMDs) are fitted well to the isochrones. In addition, this study reports 621 new OC candidates with discernible main sequence or red giant branch. It is shown that BSEC technique can discard some false negatives of previous works, which takes about three percentage of known clusters. It shows that as an EC, the color excess(or twocolor) constraint is useful for removing fake cluster member stars from the clusters that are identified from the positions and proper motions of stars, and getting more precise CMDs, when differential reddening of member stars of a cluster is not large(e.g., ΔE(G_(BP)-G_(RP)) he CMDs of 15% clusters clearer(in particular for the region near turnoff) and therefore is helpful for CMD and stellar population studies. Our result suggests that the color excess con

关键词： Galaxy stellar content-(Galaxy:)open clusters and associations general-stars fundamental parameters

UNCONDITIONAL CONVERGENCE AND ERROR ESTIMATES OF A FULLY DISCRETE FINITE ELEMENT METHOD FOR The MICROPOLAR NAVIER-STOKES EQUATIONS

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Journal of Computational Mathematics 2024年第1期42卷 71-110页

作者： Shipeng mao Jiaao Sun Wendong Xue NCMIS LSECInstitute of Computational Mathematics and Scientific/Enginnering ComputingAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

In this paper,we consider the initial-boundary value problem(IBVP)for the micropolar Naviers-Stokes equations(MNSE)and analyze a first order fully discrete mixed finite element *** first establish some regularity results for the solution of MNSE,which seem to be not available in the ***,we study a semi-implicit time-discrete scheme for the MNSE and prove L2-H1 error estimates for the time discrete ***,certain regularity results for the time discrete solution are establishes *** on these regularity results,we prove the unconditional L2-H1 error estimates for the finite element solution of ***,some numerical examples are carried out to demonstrate both accuracy and efficiency of the fully discrete finite element scheme.

关键词： Micropolar fluids Regularity estimates Euler semi-implicit scheme Mixed finite element methods Unconditional convergence

Impacts of information about COVID-19 on pig farmers'production willingness and behavior:Evidence from China

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Journal of Integrative Agriculture 2024年第4期23卷 1429-1441页

作者： Huan Chen Lei mao Yuehua Zhang School of Public Affairs Zhejiang UniversityHangzhou 310058China School of Insurance Central University of Finance and EconomicsBeijing 100081China Innovation Center of Yangtze River Delta Zhejiang UniversityJiaxing 314100China

This paper examines the impacts of information about COVID-19 on pig farmers'production willingness by using endorsement experiments and follow-up surveys conducted in 2020 and 2021 in *** results show that,first,farmers were less willing to scale up production when they received information about *** information in 2020 that the second wave of COVID-19 might occur without a vaccine reduced farmers'willingness to scale up by 13.4%,while the information in 2021 that COVID-19 might continue to spread despite the introduction of vaccine reduced farmers'willingness by 4.4%.Second,farmers whose production was affected by COVID-19 were considerably less willing to scale up,given the access to COVID-19 ***,farmers'production willingness can predict their actual production behavior.

关键词： COVID-19 randomized experiment information treatment production willingness