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Harmonizing models and observations: Data assimilation in Earth system science

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Science China Earth Sciences 2020年第8期63卷 1059-1068页

作者： xin LI Feng LIU Miao fang National Tibetan Plateau Data Center Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China Key Laboratory of Remote Sensing of Gansu Province Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

Models and observations are two fundamental methodological approaches in Earth system science(ESS). They evolve collaboratively and enhance one another. However, neither of these two approaches is perfect, and they have incompatibilities due to their methodological differences. The emergence of data assimilation(DA) has enabled these two approaches to develop in conjunction and form a harmonic ESS methodology. As a result, DA has shown a fresh vitality and applicability in ESS. This paper reviews the application of DA in the main branches of ESS, traces the coordinated evolution of DA with the methodologies of rationalism and empiricism, analyzes the relationships of DA with estimation theory and cybernetics, summarizes the advances of DA in China, and presents an outlook on the challenges facing the development of a uniform DA for ESS. DA theories and methods will continue to evolve and provide an increasingly mature methodology for enhancing the understanding and prediction of Earth as a system.

关键词： Data assimilation Model Observation Earth system science Methodology Philosophy of science Synthesis

Theoretical Study on the Reaction Mechanism between Dichlorocarbene and Armchair Single-walled Carbon Nanotubes

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Chinese Journal of Structural Chemistry 2006年第9期25卷 1120-1128页

作者： LI Rui-fang SHANG Zhen-Feng XU xiu-fang WANG Gui-Chang Department of Chemistry Nankai University Tianjin 300071 China

The reaction mechanism between CC12 and armchair single-walled carbon nanotubes （ASWCNTs）（3,3） and （4,4） has been studied by semiempirical AM1 and ab initio methods. The activation barriers of CC12 adding to ASWCNT （3,3） and （4,4） are computed and compared. The lower barrier of CC12 forms cycloaddition isomer on （3,3） maybe because the strain energy of （3,3） is larger than that of （4,4）. Our theoretical results are consistent with the experimental results.

关键词： armchair single-walled carbon nanotubes dichlorocarbene reaction mechanism theoretical study

Experimental and CFD investigations of choked cavitation characteristics of the gap flow in the valve lintel of navigation locks

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Journal of Hydrodynamics 2020年第5期32卷 997-1008页

作者： Bo Wu Ya-an Hu xin Wang xiu-jun Yan Key Laboratory of Transport Technology in Navigation Building Construction Nanjing Hydraulic Research InstituteNanjing 210029China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing 210029China School of Water Resources and Hydropower Engineering Wuhan UniversityWuhan 430072China

The cavitation is ubiquitous in the water delivery system of high hydraulic head navigation *** paper studies the choked cavitation characteristics of the gap flows in the valve lintel of the navigation locks and analyzes the critical self-aeration *** cavitation gap flow in the valve lintel is experimentally and numerically investigated.A visualized 1:1 full-scale slicing model is designed,with a high-speed camera,the details of the cavitation flow is captured without the reduced scale ***,the numerical simulations are conducted to reveal the flow structures in the *** experimental results show that the flow pattern of the gap flow in the valve lintel could be separated into four models,namely,the incipient(1)the developing,(2),the intensive,(3),and the choked(4)cavitation *** numerical simulation results are consistent with the experimental *** choked cavitation conditions are crucial to the gap flow in the valve *** the choked cavitation occurs,the gap is entirely occupied by two cavitation cloud *** gap pressure then decreases sharply to the saturated water vapor pressure at the operating *** water vapor pressure is the ultimate negative pressure in the gap that remains unchanged with the continuous decrease of the downstream *** volumetric flow rate reaches a peak,then remains constant,with the further decrease of the pressure ratio or the cavitation *** the choking point,the volumetric flow rate is proportional to the root mean square of the difference between the upstream pressure(absolute pressure)and the saturated pressure of the ***,the pressure ratio is linearly correlated with the downstream cavitation number with a slope of(1+ζc).

关键词： Cavitation cavitation control by aeration self-aerated flows critical self-aerated conditions choked cavitation

Entanglement of Three Atoms Induced by a Coherent Field

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Communications in Theoretical Physics 2006年第3X期46卷 435-439页

作者： WANG xiu-Wu CAI Jin-fang School of Science North China Electricity Power University Baoding 071003 China School of Science Beijing Institute of Technology Beijing 100081 China

We calculate the concurrence and spin squeezing parameter of three atoms induced by a coherent field. It shows that when the mean numbers of photon of the field is very small, concurrence exhibits a certain kind of approximative periodic vibration. With the increase of the mean numbers of photon, its periodicity will be interrupted. As for the relationship between the concurrence and spin squeezing, numeric result shows that under Dick model, spin squeezing serves as a sufficient but not necessary condition for concurrence.

关键词： entanglement concurrence spin squeezing

Potential inhibitors against 2019-nCoV coronavirus M protease from clinically approved medicines

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Journal of Genetics and Genomics 2020年第2期47卷 119-121页

作者： xin Liu xiu-jie Wang Key Laboratory of Genetic Network Biology Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing100101China University of Chinese Academy of Sciences Beijing100049China Innovation Academy for Seed Design Chinese Academy of SciencesBeijing100101China

Coronaviruses,members of the family Coronaviridae and sub-family Coronavirinae,are enveloped positive-strand RNA viruses which have spikes of glycoproteins projecting from their viral envelopes,thus exhibit a corona or halo-like appearance(Masters and Perlman,2013;Cui et al..2019).Coronaviruses are the causal path-ogens for a wide spectrum of respiratory and gastrointestinal diseases in both wild and domestic animals,including birds,pigs,rodents,etc(Dhama et al,2014).Previous studies have found that six strains of coronaviruses are capable to infect humans,including four strains circulating yearly to cause common cold,and other two strains which are the source for severe acute respiratory syndrome(SARS)and Middle East respiratory syndrome(MERS-CoV),respectively(Dhama et al,2014;Cui et al..2019).

关键词： respiratory envelope Middle

On indexing in the Web of Science and predicting journal impact factor

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第7期9卷 582-590页

作者： xiu-fang WU Qiang FU Ronald ROUSSEAU Journals of Zhejiang University SCIENCE （A ＆B） Zhejiang University Press Hangzhou 310027 China Zhejiang University Press Hangzhou 310028 China KHBO-Association K.U. Leuven Industrial Sciences and Technology Zeedijk 101-8400 Oostende Belgium K. U. Leuven Steunpunt O＆O Indicatoren Dekenstraat 2 B-3000 Leuven Belgium

We discuss what document types account for the calculation of the journal impact factor （JIF） as published in the Journal Citation Reports （JCR）. Based on a brief review of articles discussing how to predict JIFs and taking data differences between the Web of Science （WoS） and the JCR into account, we make our own predictions. Using data by cited-reference searching for Thomson Scientific＇s WoS, we predict 2007 impact factors （1Fs） for several journals, such as Nature, Science, Learned Publishing and some Library and Information Sciences journals. Based on our colleagues＇ experiences we expect our predictions to be lower bounds for the official journal impact factors. We explain why it is useful to derive one＇s own journal impact factor.

关键词： WoS (Web of Science). JCR (Journal Citation Renorts) Citation analysis Predicted impact factors

小数据集上基于语义的局部注意视觉Transformer方法

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计算机应用研究 2025年第1期42卷 314-320页

作者：冯欣王俊杰钟声方婷婷重庆理工大学计算机科学与工程学院重庆400054 西南大学人工智能学院重庆400715

在小数据集上从零开始训练时,视觉Transformer无法与同规模的卷积神经网络媲美。基于图像的局部注意力方法,可以显著提高ViT的数据效率,但是会丢失距离较远但相关的补丁之间的信息。为了解决上述问题,提出一种双向并行局部注意力视觉Tra... 详细信息

在小数据集上从零开始训练时,视觉Transformer无法与同规模的卷积神经网络媲美。基于图像的局部注意力方法,可以显著提高ViT的数据效率,但是会丢失距离较远但相关的补丁之间的信息。为了解决上述问题,提出一种双向并行局部注意力视觉Transformer的方法。该方法首先在特征层面上对补丁进行分组,在组内执行局部注意力,以利用特征空间中补丁之间的关系弥补信息丢失。其次,为了有效融合补丁之间的信息,将基于语义的局部注意力和基于图像的局部注意力并行结合起来,通过双向自适应学习来增强ViT模型在小数据上的性能。实验结果表明,该方法在计算量为15.2 GFLOPs和参数量为57.2 M的情况下,分别在CIFAR-10和CIFAR-100数据集上实现了97.93%和85.80%的准确性。相比于其他方法,双向并行局部注意力视觉Transformer在增强局部引导能力的同时,保持了局部注意力所需属性的有效性。

关键词：深度学习图像分类 Transformer 局部注意力基于语义的局部注意

A Nonlinear Diffusion Model for Image Restoration

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Acta Mathematicae Applicatae Sinica 2016年第3期32卷 631-646页

作者： Yong-gui ZHU xin-yan YU Bin ZHANG xiu-xiu NIU School of Science Communication University of China

In this paper, we study the ill posed Perona-Malik equation of image processing[14] and the regularized P-M model i.e. C-model proposed by Catte et al.[4]. The authors present the convex compound of these two models in the form of the system of partial differential equations. The weak solution for the equations is proved in detail. The additive operator splitting （AOS） algorithm for the proposed model is also given. Finally, we show some numeric experimental results on images.

关键词： Perona-Malik model C-model weak solutions AOS algorithm

CRYSTAL AND MOLECULAR STRUCTURE OF THE COMPLEX OF METHOXYCARBONYLETHYLTIN TRICHLORIDE WITH SALICYLIDENE-M-TOLUIDINE

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Chinese Chemical Letters 1995年第1期6卷 87-90页

作者： fang xin FU xiu Juan LI Hua De PAN Yan xinG Yong Hua LIN Department of Chemistry.Northeast Normal University.Changchun 130024 Changchun Applied Chemistry Institute Academy Sinica.Changchun 130022

The synthesis and properties of the title complex CH3OCOCH2CH2SnCl3. 2-HOC6H4CH+= NC6H4-3-CH3 are described. It crystallizes from benzene' in the monoclinic space group P2/n with Unit cell dimensions a= 10. 326 (3) .b=6. 815(8). c=12. 931 (6) A,β=111. 52(3)°, V=2088. 7(1),A3, Z=4, F(000)= 1040, μ= 16. 31cm-1. Dc =1. 67g/cm3 final R factor is 0. 037 for 3177 observed reflections, I≥3σ(I。). The tin atom in the structure of tile complex exists in a dis tored octahedral geomelry defined by three CI atoms, the C and O atoms of a chelating methoxycarbonylethyl group as well as an O atom derived from the Schiff base ligand.

关键词： ?