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Automatic modeling algorithm of stochastic error for inertial sensors

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Control Theory and Technology 2024年第1期22卷 81-91页

作者： Luodi zhao Long zhao School of Automation Science and Electrical Engineering Beihang UniversityBeijing100191China Digital Navigation Center Beihang UniversityBeijing100191China Science and Technology on Aircraft Control Laboratory Beihang UniversityBeijing100191China

This paper proposes an automatic algorithm to determine the properties of stochastic processes and their parameters for inertial error. The proposed approach is based on a recently developed method called the generalized method of wavelet moments (GMWM), whose estimator was proven to be consistent and asymptotically normally distributed. This algorithm is suitable mainly (but not only) for the combination of several stochastic processes, where the model identification and parameter estimation are quite difficult for the traditional methods, such as the Allan variance and the power spectral density analysis. This algorithm further explores the complete stochastic error models and the candidate model ranking criterion to realize automatic model identification and determination. The best model is selected by making the trade-off between the model accuracy and the model complexity. The validation of this approach is verified by practical examples of model selection for MEMS-IMUs (micro-electro-mechanical system inertial measurement units) in varying dynamic conditions.

关键词： GMWM Stochastic process Inertial sensor Sensor calibration Error model Allan variance

DNA提取前处理方法对萨拉米香肠中细菌种群结构的影响

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食品科学 2022年第4期43卷 113-118页

作者：姬庆龙赵贵明王娉赵勇胜赵晓美杨海荣陈颖中国检验检疫科学研究院北京100176

通过比较不同DNA提取前处理方法在高通量测序中对萨拉米香肠细菌种群结构的影响,为建立规范的高通量测序的操作流程优选出更适宜的前处理方法。采用直接提取法(M0)、拍击均质法(M1)和振荡珠磨法(M2)3种常用前处理方法提取萨拉米香肠中细... 详细信息

通过比较不同DNA提取前处理方法在高通量测序中对萨拉米香肠细菌种群结构的影响,为建立规范的高通量测序的操作流程优选出更适宜的前处理方法。采用直接提取法(M0)、拍击均质法(M1)和振荡珠磨法(M2)3种常用前处理方法提取萨拉米香肠中细菌DNA,利用MiSeq高通量测序技术分析萨拉米香肠中细菌16SrRNAV3-V4区基因序列,以可操作分类单元(operationaltaxonomicunit,OTU)为基础分析细菌种群结构。结果表明,M0、M1和M2的OTU数分别为319、206和253;3种方法共有的OTU数为129,占样品总OTU数的31.85%;Chao1指数分别为177.93±31.02、120.76±28.60、166.96±15.63;Shannon指数分别为2.79±0.22、2.95±0.31、3.25±0.30。在门和科分类水平,不同前处理方法获得的样品细菌种群结构相似,只有丰度上存在差异;但在属分类水平下,不同前处理方法可影响后续种群结构分析的结果。M0可增大优势菌的丰度及多样性,可用于检测样品在成熟过程中存在过的细菌。而M1和M2除去了游离DNA,只留下具有完整细胞结构的细菌菌体,更能反映出样品在取样时的细菌种群结构。当样品结构相对均一时,M1与M2的菌群结构和丰度趋于一致。本研究说明,不同的前处理方法可影响后续种群结构分析的结果。应该尽早建立统一的高通量测序操作与分析流程,确保数据的可靠性以及不同研究之间结果的可比性。

关键词：萨拉米香肠前处理方法细菌种群结构发酵肉制品

Meeting the challenges of invasive alien species

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National Science Review 2024年第3期11卷 296-298页

作者： Weijie zhao NSR news

The Xinjiang Uygur Autonomous Region of China is famous for its tomato production. Abundant sunshine, large day–night temperature difference and the abundant irrigation by snowmelt from the Tianshan Mountains produce...

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Ling-Ling Chen: RNA has its own features;don't study it as a protein

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National Science Review 2024年第2期11卷 301-305页

作者： Weijie zhao NSR

Non-coding RNA(ncRNA) has been a very active research area over the past 30 years. From small nc RNA – the discovery of RNA interference won the lead researchers the Nobel Prize, to long ncRNA(lncRNA), which has attracted much attention in recent years, various nc RNAs participate in all kinds of biological processes and show a variety of biomedical application prospects.

关键词： RNA

One dimensional CeO_(2) nanorods/poly(ethylene oxide) solid composite electrolyte for all-solid-state lithium-ion batteries

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Journal of Rare Earths 2024年第3期42卷 570-577,I0005页

作者： Yudi Guo Erqing zhao Xiaofang zhao Shuailei Liu School of Chemistry and Materials Engineering Xinxiang UniversityXinxiang453003China School of Chemistry and Chemical Engineering Henan Institute of Science and TechnologyXinxiang453003China

The research of poly(ethylene oxide)(PEO)-based solid composite electrolyte with high ionic conductivity and excellent interfacial stability is the key to the development of all-solid-state lithium-ion batteries(ASSLIBs). Herein, uniform nanorod structured CeO_(2) fillers were controllably synthesized by electrospinning, which were subsequently filled into PEO polymer to prepare CeO_(2)/PEO solid composite electrolyte. The addition of CeO_(2) nanorods can reduce both the glass transition temperature and the melting point of PEO polymer, and also interact with PEO and lithium bis(trifluoromethanesulphonyl)imide(LITFSI) by Lewis acid—base reaction. Therefore, the solid composite electrolyte exhibits a high ionic conductivity of 4.52 × 10^(-4)S/cm, a wide electrochemical stability window of about 4.8 V, and a good interfacial stability with Li at 55℃. Moreover, the LiFePO_4/Li ASSLIB divulges the discharging specific capacity of 165, 162, 156 and 146 mA,h/g at 0.2, 0.5, 1 and 2 C, respectively, and achieves the capacity retention of 90.3% after 150 cycles at 0.5 C. Consequently, one dimensional CeO_(2) nanorods can be considered as an alternative filler for polymeric solid electrolyte.

关键词： Poly(ethylene oxide) Solid composite electrolyte CeO_(2)nanorods Ionic conductivity Rare earths

具有复发的SEILR谣言传播模型的动力学分析

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重庆理工大学学报（自然科学） 2023年第5期37卷 204-209页

作者：赵勇胜侯强张磊中北大学理学院太原030051

基于谣言的传播机制,考虑人际因素导致的谣言复发,建立了一个SEILR谣言传播模型,研究了人际因素对谣言传播的影响。首先,给出谣言传播的阈值R 0,并分析了R 0<1时,无谣言平衡点的稳定性;其次,分析了多平衡态的存在性,并给出了模型发生后... 详细信息

基于谣言的传播机制,考虑人际因素导致的谣言复发,建立了一个SEILR谣言传播模型,研究了人际因素对谣言传播的影响。首先,给出谣言传播的阈值R 0,并分析了R 0<1时,无谣言平衡点的稳定性;其次,分析了多平衡态的存在性,并给出了模型发生后向分支的条件,然后通过构造Lyapunov函数证明了退化模型正平衡点的全局渐近稳定性;最后,通过数值模拟发现模型会出现退化的Hopf分支,模型存在2个极限环,其中大极限环不稳定,小极限环稳定。研究结果说明人际因素导致的谣言复发会改变谣言的动态传播趋势。

关键词：谣言传播稳定性后向分支 Hopf分支

A DIRECT DISCONTINUOUS GALERKIN METHOD FOR TIME FRACTIONAL DIFFUSION EQUATIONS WITH FRACTIONAL DYNAMIC BOUNDARY CONDITIONS

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Journal of Computational Mathematics 2024年第1期42卷 156-177页

作者： Jingjun zhao Wenjiao zhao Yang Xu School of Mathematics Harbin Institute of TechnologyHarbin 150001China

This paper deals with the numerical approximation for the time fractional diffusion problem with fractional dynamic boundary *** well-posedness for the weak solutions is studied.A direct discontinuous Galerkin approach is used in spatial direction under the uniform meshes,together with a second-order Alikhanov scheme is utilized in temporal direction on the graded mesh,and then the fully discrete scheme is ***,the stability and the error estimate for the full scheme are analyzed in *** experiments are also given to illustrate the effectiveness of the proposed method.

关键词： Time fractional diffusion equation Numerical stability Convergence

Conformation and Counterion Distribution of Polyelectrolyte in Solution as Viewed from Dielectric Approach

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Chinese Journal of Polymer Science 2024年第9期42卷 1278-1301,I0005页

作者： Kong-Shuang zhao College of Chemistry Bejing Normal UniversityBejing 100875China

Polyelectrolyte solutions are more variable than uncharged macromolecule due to electrical interaction between charged molecules and surrounding ***,the subject of polyelectrolyte solutions has attracted a wide range of interests in both basic and applied research,and has also been extensively ***,the understanding of the molecular dynamics and conformation of polyelectrolytes in solution remains to be deepened,and universal consensus on some key issues have not been *** methods have contributed to solving the above problems in different ways,including dielectric relaxation spectroscopy(DRS).In this perspective,we briefly reviewed the history of dielectric spectroscopic research on polyelectrolyte solution,with emphasis on summarizing our *** particular,we expound the characteristics of DRS and its ability to obtain the internal information of the system of ***,we evaluate the advantages and limitations of the dielectric method and discussed future prospects of this field.

关键词： Polyelectrolyte Dielectric relaxation spectroscopy Chain conformation Thermosensitive microgel PNIPAM microgel Spherical polyelectrolyte brushes

基于特征约束关系的航天器大部件装配机器人机型设计方法及应用

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机械工程学报 2023年第16期59卷 233-242页

作者：蔡大军姚建涛高炜骅易旺民赵永生燕山大学河北省并联机器人与机电系统实验室秦皇岛066004 燕山大学工程训练中心秦皇岛066004 燕山大学先进锻压成形技术与科学教育部重点实验室秦皇岛066004 北京卫星环境工程研究所北京100094

面向狭长任务空间航天器大部件装配的定位调姿需求,提出一种装配机器人机型设计方法。该方法以大型构件装配对接过程中存在的主要特征为和空间约束为主要参考,结合空间自由曲面几何理论,总结装配过程中存在的多种典型特征,基于装配特征... 详细信息

面向狭长任务空间航天器大部件装配的定位调姿需求,提出一种装配机器人机型设计方法。该方法以大型构件装配对接过程中存在的主要特征为和空间约束为主要参考,结合空间自由曲面几何理论,总结装配过程中存在的多种典型特征,基于装配特征对应的数学描述,建立装配几何特征到机器人运动维度的映射关系;定义装配过程中轨迹规划涉及到的多种空间、位姿状态的表示方法,明确轨迹规划中的各类约束相互关系,确定机器人运动的边界范围。以典型作业环境空间站工作舱为例,研发基于PPRRPR构型的航天装配机器人。从机构构态和运动特征两个方面,结合串/并联机构的优势以及在对应约束空间下的行为特性,进一步提出基于机构行为特征的机器人优化设计方法,建立混联装配机器人的概念模型,为特定任务环境下装配及搬运大型装备的机构设计提供了一定的参考。

关键词：装配特征空间约束行为特征机型设计混联