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基于指数滤波模型的青藏高原根系层土壤水分估算研究

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高原气象 2025年第1期44卷 134-149页

作者：宋雨曦苏建宾文军郑东海成都信息工程大学大气科学学院高原大气与环境四川省重点实验室四川成都610225 中国科学院青藏高原研究所青藏高原地球系统与资源环境全国重点实验室国家青藏高原科学数据中心北京100101

高精度、长时序的土壤水分数据对青藏高原陆-气相互作用研究十分重要。然而,当前青藏高原土壤水分研究大多聚焦表层土壤水分的卫星反演,根系层土壤水分的估算研究相对匮乏。基于青藏高原五个土壤水分观测网络(狮泉河、帕里、那曲、黑河... 详细信息

高精度、长时序的土壤水分数据对青藏高原陆-气相互作用研究十分重要。然而,当前青藏高原土壤水分研究大多聚焦表层土壤水分的卫星反演,根系层土壤水分的估算研究相对匮乏。基于青藏高原五个土壤水分观测网络(狮泉河、帕里、那曲、黑河上游、玛曲)数据,本文系统评估了指数滤波模型在青藏高原不同气候与下垫面区域估算根系层(10 cm/20 cm/40 cm)土壤水分的适用性,探讨了不同环境因素(土壤、气候、植被)对模型特征时长参数T值的影响,最后评估了利用三种方法(各观测网络或青藏高原站点最优T值(Topt)中位数、随机森林模型)获取的区域T值估算青藏高原根系层土壤水分的可靠性。研究发现:(1)随着土壤深度的增加,根系层与表层土壤水分的相关性降低,而其空间异质性增大,导致指数滤波模型的应用精度降低,而模型T值及其空间异质性增大;(2)空间上随着降水量和土壤含水量的增加,根系层与表层土壤水分的相关性增大,而其空间异质性降低,使得指数滤波模型的应用精度上升,而其在区域内不同站点应用精度的差异呈现降低趋势;(3)土壤性质尤其是砂土含量是控制青藏高原区域T值空间分布的主要因素;(4)T值的获取对指数滤波模型在青藏高原的应用精度影响较小,当前常用的区域Topt中位数和随机森林模型均能获取相对合理的区域T值和取得一致且相对准确的模拟结果。本研究的发现有望推动利用指数滤波模型基于卫星表层土壤水分资料准确获取青藏高原根系层土壤水分。

关键词：青藏高原指数滤波模型根系层土壤水分不同气候与下垫面区域

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Kepler's third law of n-body system

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Science China(Physics,Mechanics & Astronomy) 2018年第9期61卷 107-108页

作者： Zhen-su She Department of Mechanics and Engineering Science Peking University

Newton＇s gravitational law and its derived Kapler＇s orbit of planetary motions are the very first triumph of science, which confirms that a purely human＇s invention of mathematics is able to accurately describe observations in nature. For the past three centuries, the frontier of science has moved to almost all areas of human experience, yet some basic problem in celestial mechanics has remained unsolved, despite the effort of many great minds like Newton （1687）, Euler （1760） and Lagrange （1776）, among others.

关键词：法律开普勒 Lagrange 系统身体 Euler 牛顿科学

Non-negative locality-constrained vocabulary tree for finger vein image retrieval

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Frontiers of Computer Science 2019年第2期13卷 318-332页

作者： Kun su Gongping YANG Lu YANG Peng su Yilong YIN School of Computer Science and Technology Shandong University Jinan 250101 China School of Mechanical Electrical and Information Engineering Shandong University (Weihai)Weihai 264209 China School of Computer Science and Tech no logy Shandong University of Finance and Econo mics Jinan 250014 China School of Mathematics Dali University Dali 671000 China

Finger vein image retrieval is a biometric identification technology that has recently attracted a lot of attention. It has the potential to reduce the search space and has attracted a considerable amount of research effort recently. It is a challenging problem owing to the large number of images in biometric databases and the lack of efficient retrieval schemes. We apply a hierarchical vocabulary tree modelbased image retrieval approach because of its good scalability and high efficiency. However, there is a large accumulative quantization error in the vocabulary tree (VT) model that may degrade the retrieval precision. To solve this problem, we improve the vector quantization coding in the VT model by introducing a non-negative locality-constrained constraint: the non-negative locality-constrained vocabulary tree-based image retrieval model. The proposed method can effectively improve coding performanee and the discriminative power of local features. Extensive experiments on a large fused finger vein database demonstrate the superiority of our encoding method. Experimental results also show that our retrieval strategy achieves better performanee than other state-of-theart methods, while maintaining low time complexity.

关键词： non-negative locality-constrained vocabulary tree finger vein image retrieval large scale inverted indexing

Photoredox-catalyzed amide-directed selective sp^3 C–H bond functionalization

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Science Bulletin 2016年第24期61卷 1892-1893页

作者： Wenliang Wu Weiping su State Key Laboratory of Structure Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

Over the past century, transition metal-catalyzed crosscoupling reactions have evolved to be among the most used C-C bond forming reactions in chemical synthesis. An important remaining challenge is to synthesis with heightened levels of efficiency by new method. A powerful new class of reactions that introduce oxidized functionality directly into sp3 C-H bonds of hydrocarbons is emerging [1, 2]. Despite important advances in the aliphatic C-H bond activations, selective functionalization with complex substrates has only been demonstrated for activated C-H bonds such as location adjacent to a heteroatom or substrate with directing groups [3]. High-efficient oxidations of isolated, unactivated sp3 C-H bonds are rare. The challenge to solve this problem lies in discovering new methodology that is both highly efficient and predictably selective for oxidizing these inert C-H bonds.

关键词：过渡金属催化 C-H键氧化还原 sp3 活化定向选择交叉偶联反应酰胺

Measurement-device-independent quantum secret sharing and quantum conference based on Gaussian cluster state

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Science China(Information Sciences) 2019年第7期62卷 196-209页

作者： Yu WANG Caixing TIAN Qi su Meihong WANG Xiaolong su State Key Laboratory of Cryptology State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University Collaborative Innovation Center of Extreme Optics Shanxi University

Cluster state is the basic resource for one-way quantum computation and a valuable resource for establishing quantum network, because it has a flexible and varied composition form. We present measurement-device-independent quantum secret sharing(QSS) and quantum conference(QC) schemes based on continuous variable(CV) four-mode cluster state with different structures. The users of the protocol prepare their own Einstein-Podolsky-Rosen(EPR) states, respectively. One mode of these EPR states is sent to an untrusted relay where a generalized Bell measurement creates different types of CV cluster states among four users, while the other mode is kept at their own station. We show that a shared secret key for QSS and QC schemes is distilled based on the shared quantum correlation among four users. QC and four users QSS are implemented based on the star shape CV cluster state. QSS with three users are implemented based on the linear or square shape CV cluster states. The results show that the secure transmission distance for an asymmetric network, where the transmission distances between the users and relay are different, is longer than that of a symmetric network, where the transmission distances between the users and relay are the same. The presented schemes provide concrete references for establishing quantum network with the CV cluster state.

关键词： measurement-device-independent cluster state quantum network continuous variable quantum secret sharing

The insight of why:Causal inference in Earth system science

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Science China Earth Sciences 2023年第10期66卷 2169-2186页

作者： Jianbin su Duxin CHEN Donghai ZHENG Yang su Xin LI National Tibetan Plateau Data Center State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing100101China School of Mathematics Southeast UniversityNanjing210096China Northwest Institute of Eco-Environment and Resources University of Chinese Academy of SciencesLanzhou730000China

The utilization of big Earth data has provided insights into the planet we inhabit in unprecedented dimensions and *** the concealed causal connections within intricate data holds paramount importance for attaining a profound comprehension of the Earth *** methods founded on correlation have predominated in Earth system science(ESS)for a long ***,correlation does not imply causation,especially when confronted with spurious correlations resulting from big ***,traditional correlation and regression methods are inadequate for addressing causation related problems in the Earth *** recent years,propelled by advancements in causal theory and inference methods,particularly the maturity of causal discovery and causal graphical models,causal inference has demonstrated vigorous vitality in various research directions in the Earth system,such as regularities revealing,processes understanding,hypothesis testing,and physical models *** paper commences by delving into the origins,connotations,and development of causality,subsequently outlining the principal frameworks of causal inference and the commonly used methods in ***,it reviews the applications of causal inference in the main branches of the Earth system and summarizes the challenges and development directions of causal inference in *** the big Earth data era,as an important method of big data analysis,causal inference,along with physical model and machine learning,can assist the paradigm transformation of ESS from a model-driven paradigm to a paradigm of integration of both mechanism and *** forward,the establishment of a meticulously structured and normalized causal theory can act as a foundational cornerstone for fostering causal cognition in ESS and propel the leap from fragmented research towards a comprehensive understanding of the Earth system.

关键词： Causal inference Machine learning Earth system science Causal discovery Artificial Intelligence

Delay-dependent robust H_∞control of convex polyhedral uncertain fuzzy systems

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Journal of Systems Engineering and Electronics 2008年第6期19卷 1191-1198页

作者： Gong Cheng su Baoku Dept. of Control Theory and Control Engeering Harbin Inst. of Technology Harbin 150001 P. R. China

The robust H∞ control problem for a class of uncertain Takagi-sugeno fuzzy systems with timevarying state delays is studied. The uncertain parameters are supposed to reside in a polytope. Based on the delay-dependent Lyapunov functional method, a new delay-dependent robust H∞ fuzzy controller, which depends on the size of the delays and the derivative of the delays, is presented in term of linear matrix inequalities （LMIs）. For all admissible uncertainties and delays, the controller guarantees not only the asymptotic stability of the system but also the prescribed H∞ attenuation level. In addition, the effectiveness of the proposed design method is demonstrated by a numerical example.

关键词： robust H∞ control delay-dependent polyhedral uncertainty fuzzy systems

New results on the robust stability analysis of neural networks with discrete and distributed time delays

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Journal of Systems Engineering and Electronics 2008年第3期19卷 592-597页

作者： su Weiwei Chen Yiming Coll. of Science Yanshan Univ. Qinhuangdao 066004 P. R. China

Delay-dependent robust stability of cellular neural networks with time-varying discrete and distributed time-varying delays is considered. Based on Lyapunov stability theory and the linear matrix inequality （LMIs） technique, delay-dependent stability criteria are derived in terms of LMIs avoiding bounding certain cross terms, which often leads to conservatism. The effectiveness of the proposed stability criteria and the improvement over the existing results are illustrated in the numerical examples.

关键词： neural networks delay-dependent robust stability Lyapunov stability theory linear matrix inequality(LMI) distributed delay norm-bounded uncertainties.

Dynamic Behavior Analysis of Finger Seal Based on Equivalent Dynamic Model

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Chinese Journal of Mechanical Engineering 2010年第5期23卷 590-599页

作者： su Hua CHEN Guoding School of Mechatronics Northwestern Polytechnical University Xi ＇an 710072 China

Finger seal is a new technology developed for gas path sealing in gas turbine *** has been paid attention to its good sealing performance and lower manufacture *** vibration behavior of finger seal is not be considered in performance analysis for the contact finger seal with compliant geometric configuration,then this will influence the reliability of the performance analysis and the parametric design of a finger *** to the dynamic character of finger seal,the harmonic vibration and free vibration models of a repetitive section of a two-layer finger seal that contains one high and one low finger seal are established *** dynamic behavior of finger seal in different working conditions is obtained based on the dynamic response analysis of finger＇s *** dynamic low hysteresis and low wear terms based on the equivalent dynamic model of finger seal are put forward,which can be used to predict the dynamic behavior of finger *** an example,the dynamic behaviors of an 8-layer finger seal and a 10-layer finger seal were predicted,and the validity of the prediction was demonstrated by the leakage test results of these two finger *** work presented here not only could make the dynamic analysis of finger seal with complicated structure simple and easy especially for multi-layer finger seal system,but also suggest a useful method for designing the finger seal with good dynamic behavior by means of different seal layers assembly.

关键词： finger seal dynamic behavior vibration