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Frontiers of environmental Science & engineering 2020年第5期14卷 137-145页

作者： Haizhou liu Xuejun yu Department of Chemical and environmental engineering University of California at RiversideRiversideCA 92521USA

Chromium(Cr)typically exists in either trivalent and hexavalent oxidation states in drinking water,i.e.,Cr(Ⅲ)and Cr(Ⅵ),with Cr(Ⅵ)of particular concern in recent years due to its high toxicity and new regulatory *** Account presented a critical analysis of the sources and occurrence of Cr(Ⅵ)in drinking water in the United States,analyzed the equilibrium chemistry of Cr(Ⅵ)species,summarized important redox reaction relevant to the fate of Cr(Ⅵ)in drinking water,and critically reviewed emerging Cr(Ⅵ)treatment *** is a wide occurrence of Cr(Ⅵ)in US source drinking water,with a strong dependence on groundwater sources,mainly due to naturally weathering of chromium-containing *** regarding traditional Cr(Ⅵ)treatment include chemical cost,generation of secondary waste and inadvertent re-generation of Cr(Ⅵ)after *** overcome these challenges,reductive Cr(Ⅵ)treatment technologies based on the application of stannous tin or electron-releasing titanium dioxide photocatalyst hold extreme promise in the *** moving forward in the right direction,three key questions need further exploration for the technology implementation,including effective management of residual waste,minimizing the risks of Cr(Ⅵ)re-occurrence downstream of drinking water treatment plant,and promote the socioeconomic drivers for Cr(Ⅵ)control in the future.

关键词： Chromium Chemistry Treatment Future outlook

A Differential evolution Flower Pollination Algorithm with Dynamic Switch Probability

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Chinese Journal of electronics 2019年第4期28卷 737-747页

作者： liu Jingsen liu Li LI yu Institute of Intelligent Network system Henan University College of Software Henan University Institute of Management Science and engineering Henan University

For the shortcomings of the basic flower pollination algorithm, this paper proposes a differential evolution flower pollination algorithm with dynamic switch probability based on the Weibull *** new algorithm improved the convergence rate and precision. The switch probability is improved by Weibull distribution function combined with the number of iterations. It can balance the relationship between the global pollination and the local pollination to improve the overall optimization performance of the *** mutation operator is merged into the global pollination process to increase diversity of the population,enhance the ability of the algorithm’s global search and avoid premature convergence. In the process of local pollination, directed mutation and crossover operation of the differential evolution are incorporated, it makes the individual flower position update with the memory function, which can choose the direction of variation reasonably. The use of cross-operation can avoid new solutions crossing the boundary. Convergence rate is improved and the algorithm can approach the global optimal solution continuously. Theoretical analysis proved the convergence and time complexity of the improved algorithm. The simulation results based on the function optimization problem show that the improved algorithm has better performance of optimization, faster convergence speed and higher convergence accuracy.

关键词： Flower pollination algorithm Dynamic switch probability Random mutation operator Differential evolution Optimization accuracy Convergence rate

Line-of-sight based three-dimensional path following control for an underactuated robotic dolphin

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Science China(Information Sciences) 2021年第1期64卷 215-226页

作者： Jincun liu Zhenna liu Junzhi yu State Key Laboratory for Turbulence and Complex System Department of Mechanics and Engineering ScienceBIC-ESATCollege of EngineeringPeking University Department of electrical and Automation Shandong Labor Vocational and Technical College State Key Laboratory of Management and Control for Complex Systems Institute of AutomationChinese Academy of Sciences

This paper investigates the three-dimensional(3-D) path following control problem for an underactuated robotic dolphin. With a comprehensive consideration of the mechanical constraint and swimming principle of the robotic dolphin, a decoupling motion strategy is proposed to produce yaw and pitch maneuvers simultaneously. Then, kinematics and dynamics models for 3-D dolphin-like swimming are established,followed by simulations of the path following control. Furthermore, a novel lookahead based 3-D line-ofsight(LOS) guidance law is developed and implemented to obtain desired attitude angles with its simplicity,intuitiveness, and small computational footprint. Finally, simulation results illustrate the feasibility and effectiveness of the proposed path following control methods.

关键词： robotic dolphin path following 3-D LOS guidance law decoupling motion

Mathematical foundation of liutex theory

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Journal of Hydrodynamics 2022年第6期34卷 981-993页

作者： Chaoqun liu Yifei yu Department of Mathematics University of Texas at ArlingtonArlingtonTexas76019USA

liutex is a mathematical definition of vortex,which is called the third generation of vortex definition and *** paper introduces the mathematical foundation of the liutex theoretical system including differences in definition and operations between tensor/vector and *** right version of velocity gradient tensor matrix is given to correct the old version which has been widely distributed by many mathematics and fluid dynamics textbooks.A unique velocity gradient principal matrix is *** mathematical foundation for liutex definition is *** coordinate rotation(Q-and P-rotation)for principal coordinate system and principal matrix is derived,which is the key issue of the new fluid *** divergence of velocity gradient tensor is given in different forms which may be beneficial in developing new governing equations for fluid dynamics.

关键词： liutex mathematical foundation tensor matrix velocity gradient fluid dynamics

The burden of upper motor neuron involvement is correlated with the bilateral limb involvement interval in patients with amyotrophic lateral sclerosis:a retrospective observational study

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Neural Regeneration Research 2025年第5期20卷 1505-1512页

作者： Jieying Wu Shan Ye Xiangyi liu Yingsheng Xu Dongsheng Fan Department of Neurology Peking University Third HospitalBeijingChina Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases BeijingChina Key Laboratory for Neuroscience National Health Commission/Ministry of EducationPeking UniversityBeijingChina

Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor *** bilateral limb involvement significantly affects patients'daily lives and may lead them to be confined to ***,the effect of upper and lower motor neuron impairment and other risk factors on bilateral limb involvement is *** address this issue,we retrospectively collected data from 586 amyotrophic lateral sclerosis patients with limb onset diagnosed at Peking University Third Hospital between January 2020 and May 2022.A univariate analysis revealed no significant differences in the time intervals of spread in different directions between individuals with upper motor neuron-dominant amyotrophic lateral sclerosis and those with classic amyotrophic lateral *** used causal directed acyclic graphs for risk factor determination and Cox proportional hazards models to investigate the association between the duration of bilateral limb involvement and clinical baseline characteristics in amyotrophic lateral sclerosis *** factor analyses revealed that higher upper motor neuron scores(hazard ratio[HR]=1.05,95%confidence interval[CI]=1.01–1.09,P=0.018),onset in the left limb(HR=0.72,95%CI=0.58–0.89,P=0.002),and a horizontal pattern of progression(HR=0.46,95%CI=0.37–0.58,Pere risk factors for a shorter interval until bilateral limb *** results demonstrated that a greater degree of upper motor neuron involvement might cause contralateral limb involvement to progress more quickly in limb-onset amyotrophic lateral sclerosis *** findings may improve the management of amyotrophic lateral sclerosis patients with limb onset and the prediction of patient prognosis.

关键词： amyotrophic lateral sclerosis bilateral limb involvement Cox proportional hazards regression model horizontal spread restricted cubic spline analysis time interval upper motor neuron vertical spread

Half exact Functors Associated with Cotorsion Pairs on exact Categories

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Acta Mathematica Sinica,english Series 2019年第8期35卷 1334-1356页

作者： yu liu School of Mathematics Southwest Jiaotong University

In the previous article "Hearts of twin cotorsion pairs on exact categories. J. Algebra, 394,245–284(2013)", we introduced the notion of the heart for any cotorsion pair on an exact category with enough projectives and injectives, and showed that it is an abelian category. In this paper, we construct a half exact functor from the exact category to the heart. This is an analog of the construction of Abe and Nakaoka for triangulated categories. We will also use this half exact functor to find out a sufficient condition when two different hearts are equivalent.

关键词： Cotorsion pair heart half exact functor equivalence

电刺激诱导miR-741-3p调控Radil促进施万细胞的迁移

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中国组织工程研究 2025年第19期29卷 4038-4043页

作者：刘庆高博杨霄姜宇王培承德医学院附属医院河北省承德市067000 承德医学院河北省承德市067000

背景:越来越多的动物实验和临床研究证实电刺激可以促进周围神经损伤修复,具体的机制尚未完全明确。目的:探讨电刺激诱导miR-741-3p调控Radil对施万细胞迁移的影响。方法:①12只雄性SD大鼠,随机分为电刺激组和对照组,电刺激组在坐骨神... 详细信息

背景:越来越多的动物实验和临床研究证实电刺激可以促进周围神经损伤修复,具体的机制尚未完全明确。目的:探讨电刺激诱导miR-741-3p调控Radil对施万细胞迁移的影响。方法:①12只雄性SD大鼠,随机分为电刺激组和对照组,电刺激组在坐骨神经挤压伤后连续电刺激7 d,对照组在坐骨神经挤压后不做任何处理。术后第7天取损伤处神经,利用荧光原位杂交技术检测两组miR-741-3p的表达差异。②通过miRDB、TargetScan和miRWalk数据库预测miR-741-3p靶基因。③将miR-741-3p模拟物及其对照、miR-741-3p抑制物及其对照、Radil siRNA及其对照、miR-741-3p抑制物+Radil siRNA及miR-741-3p抑制物+siRNA对照对施万细胞进行转染,采用RT-PCR检测转染效率,Transwell小室检测施万细胞的迁移能力。结果与结论:①电刺激组神经残端miR-741-3p荧光强度低于对照组;②数据库预测结果显示有69个基因可能是miR-741-3p靶基因,Radil是预测靶基因之一,主要参与细胞黏附和迁移;③与miR-741-3p抑制物对照组相比,miR-741-3p抑制物组施万细胞迁移数增多(P<0.05);与miR-741-3p模拟物对照组相比,miR-741-3p模拟物组施万细胞迁移数减少(P<0.05);与siRNA对照组相比,Radil siRNA组施万细胞迁移数减少(P<0.05);④与miR-741-3p抑制物对照组相比,miR-741-3p抑制物组Radil的表达水平升高;与miR-741-3p模拟物对照组相比,miR-741-3p模拟物组Radil的表达水平降低;⑤与miR-741-3p抑制物+siRNA对照组相比,miR-741-3p抑制物+Radil siRNA组施万细胞迁移数减少(P<0.05)。结果表明,电刺激通过下调miR-741-3p调控Radi的表达来促进施万细胞迁移。

关键词：施万细胞电刺激 miR-741-3p Radil 细胞迁移神经再生

基于机器学习的农田土壤抗剪强度参数检测方法研究

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农机化研究 2025年第1期47卷 7-15页

作者：于艳艳朱龙图刘鹤吉林农业大学信息技术学院长春130118 云南农业大学机电工程学院昆明650201 农业农村部长江中下游农业装备重点实验室武汉430070

土壤抗剪强度参数包括粘聚力和内摩擦角,是评价土壤侵蚀敏感性和反映耕层耕作性能的重要指标。为实现农田土壤抗剪切强度参数的快速检测,提出了一种基于机器学习的土壤抗剪切强度参数检测方法。以STM32单片机为核心处理器,采用圆锥杆、... 详细信息

土壤抗剪强度参数包括粘聚力和内摩擦角,是评价土壤侵蚀敏感性和反映耕层耕作性能的重要指标。为实现农田土壤抗剪切强度参数的快速检测,提出了一种基于机器学习的土壤抗剪切强度参数检测方法。以STM32单片机为核心处理器,采用圆锥杆、滚珠丝杆滑台、三角支架等构建土壤数据采集装置,利用DYMH-103柱式压力传感器和FlexiForce薄膜传感器分别检测圆锥杆贯入土壤的锥尖阻力和锥侧压力,采用CSF11土壤水分传感器获取土壤含水率信息,通过多传感器数据特征向量提取构建建模数据集。数据集相关性分析结果表明:土壤抗剪强度参数与锥尖阻力、锥侧压力和土壤含水率之间具有明显相关性。利用蒙特卡罗交叉验证(Monte Carlo Cross Validation,MCCV)剔除了数据集中的4个异常样本;同时,提出了一种eLM-PLSR组合建模算法,以决定系数R^(2)和RPD为评价指标,对比评估了eLM、PLSR和eLM-PLSR 3种不同机器学习模型,结果表明:eLM-PLSR模型预测性能优于eLM模型和PLSR模型;检测粘聚力时,对应的R^(2)、RPD分别为0.919和3.475;检测内摩擦角时,对应的R 2和RPD分别为0.910和3.304。研究结果可为土壤抗剪强度参数快速测量提供参考。

关键词：机器学习土壤抗剪强度多传感器特征向量预测模型

Formation of disinfection byproducts from accumulated soluble products of oleaginous microalga after chlorination

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Frontiers of environmental Science & engineering 2017年第6期11卷 1-7页

作者： yu liu Qiao Zhang yu Hong Beijing Key Laboratory for Source Control Technology of Water Pollution Beijing Forestry University Beijing 100083 China

When microalgae are simultaneously applied for wastewater treatment and lipid production, soluble algal products （SAP） should be paid much attention, as they are important precursors for formation of disinfection byproducts （DBPs）, which have potential risks for human health. Chlorella sp. HQ is an oleaginous microalga that can generate SAP during growth, especially in the exponential phase. This study investigated the contribution of SAP from Chlorella sp. HQ to DBP formation after *** predominant DBP precursors from SAP were identified with the 3D excitation-emission matrix fluorescence. After chlorination, a significant reduction was observed in the fluorescence intensity of five specific fluorescence regions, particularly aromatic proteins and soluble microbial by-product-like regions, accompanied with slight shifting of the peak. The produced DBPs were demonstrated to include trihalomethanes and haloacetic acids. As the algal cultivation time was extended in wastewater, the accumulated SAP strengthened the formation of DBPs. The trend for DBP formation was as follows： chloroform〉dichloroacetic acid〉trichloroacetic acid.

关键词： Chlorella sp. HQ Chlorination Disinfection byproducts Fluorescence spectroscopy Soluble algal products

error model identification of inertial navigation platform based on errors-in-variables model

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Journal of Systems engineering and electronics 2009年第2期20卷 388-393页

作者： liu Ming liu yu Su Baoku Space Control and Inertial Technology Research Center Harbin Inst. of Technology Harbin 150001 P. R. China

Because the real input acceleration cannot be obtained during the error model identification of inertial navigation platform, both the input and output data contain noises. In this case, the conventional regression model and the least squares （LS） method will result in bias. Based on the models of inertial navigation platform error and observation error, the errors-in-variables （eV） model and the total least squares （TLS） method axe proposed to identify the error model of the inertial navigation platform. The estimation precision is improved and the result is better than the conventional regression model based LS method. The simulation results illustrate the effectiveness of the proposed method.

关键词： errors-in-variables model total least squares method inertial navigation platform error model identification