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Study on oxygen transport and titanium oxidation in coating cracks under parallel gas flow based on LBM modelling

Chinese Journal of Chemical Engineering 2023年第4期56卷 15-24页

作者： Shengfeng Luo Song Zhang Yiping Zeng Hui Zhang lili zheng Zhaopeng Xu Department of Engineering Physics Tsinghua UniversityBeijing 100084China Department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhen 518055China Institute for Aero Engine Tsinghua UniversityBeijing 100084China Shenzhen Smart Hua Information Technology Research Co. Ltd.Shenzhen 518000China School of Aerospace Engineering Tsinghua UniversityBeijing 100084China Chinese Academy of Agricultural Mechanization Sciences Beijing 100084China

The oxygen transportation from surrounding air to coating cracks is an important factor in the oxidation and ignition of titanium alloy. In this work, the oxygen transport and surface oxidation of titanium in inclined cracks of coating under parallel airflow are studied with the lattice Boltzmann method(LBM).A boundary scheme of LBM about surface reaction is developed. The conversion factors are utilized to build the relationship between the physical scale and the lattice scale. The reliability of the LBM model is validated by the finite element method(FEM). The results show that the convective mass transport driven by the surrounding airflow and the vortex structure formed inside the crack are the two significant factors that influence the oxygen transport in cracks. The convective mass transfer plays a major role in oxygen transport when the inclination angle of the crack is small. For the cases with a large inclination angle, the oxygen transfer from the top to the bottom of the crack is mainly controlled by mass diffusion mechanism. The oxygen concentration in inclined cracks is generally less than that in vertical cracks, and oxidation and ignition of the substrate titanium might be more likely to occur in relatively vertical cracks.

关键词： Coating crack Oxidation Transport Ignition Numerical simulation

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俄罗斯北高加索地区车臣人的信仰变迁:进程与特点

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世界宗教文化 2024年第1期 15-22页

作者：郑丽丽兰州大学西北少数民族研究中心-政治与国际关系学院兰州大学外国语学院

北高加索地区作为俄罗斯的南部边疆,处于民族和宗教冲突的中心地带。伊斯兰教是北高加索地区车臣人最重要的社会意识形态和文化。本文主要探讨俄罗斯北高加索地区车臣人历史上宗教信仰的变迁进程和特点。伊斯兰教在传入车臣社会的过程中... 详细信息

北高加索地区作为俄罗斯的南部边疆,处于民族和宗教冲突的中心地带。伊斯兰教是北高加索地区车臣人最重要的社会意识形态和文化。本文主要探讨俄罗斯北高加索地区车臣人历史上宗教信仰的变迁进程和特点。伊斯兰教在传入车臣社会的过程中,逐渐与车臣社会的多神教、自然崇拜、基督教等元素相融合,形成了具有本土特色的伊斯兰传统。与此同时,在与沙俄帝国斗争中发起的伊斯兰“圣战”传统和宗教极端思想影响至今,使得北高加索地区深受宗教极端主义和恐怖主义的威胁。

关键词：俄罗斯北高加索地区车臣人信仰变迁本土化

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Noninvasive Assessment of Liver Fibrosis and Inflammation in Chronic Hepatitis B:A Dual-task Convolutional Neural Network(DtCNN)Model Based on Ultrasound Shear Wave Elastography

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Journal of Clinical and Translational Hepatology 2022年第6期10卷 1077-1085页

作者： Chengyan Wang lili zheng Yan Li Shujun Xia Jun Lv Xumei Hu Weiwei Zhan Fuhua Yan Ruokun Li Xinping Ren Human Phenome Institute Fudan UniversityShanghaiChina Ultrasound Department Ruijin Hospital Wuxi BranchShanghai Jiao Tong University School of MedicineWuxiJiangsuChina Department of Radiology Ruijin HospitalShang-hai Jiao Tong University School of MedicineShanghaiChina Ultrasound Department Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghaiChina School of Computer and Control Engineering Yantai UniversityYantaiShandongChina

Background and Aims:Liver stiffness(LS)measured by shear wave elastography(SWE)is often influenced by hepat-ic inflammation.The aim was to develop a dual-task convo-lutional neural network(DtCNN)model for the simultaneous staging of liver fibrosis and inflammation activity using 2D-SWE.Methods:A total of 532 patients with chronic hepatitis B(CHB)were included to develop and validate the DtCNN model.An additional 180 consecutive patients between De-cember 2019 and April 2021 were prospectively included for further validation.All patients underwent 2D-SWE examina-tion and serum biomarker assessment.A DtCNN model con-taining two pathways for the staging of fibrosis and inflam-mation was used to improve the classification of significant fibrosis(≥F2),advanced fibrosis(≥F3)as well as cirrhosis(F4).Results:Both fibrosis and inflammation affected LS measurements by 2D-SWE.The proposed DtCNN performed the best among all the classification models for fibrosis stage[significant fibrosis AUC=0.89(95%CI:0.87-0.92),ad-vanced fibrosis AUC=0.87(95%CI:0.84-0.90),liver cirrho-sis AUC=0.85(95%CI:0.81-0.89)].The DtCNN-based pre-diction of inflammation activity achieved AUCs of 0.82(95%CI:0.78-0.86)for grade≥A1,0.88(95%CI:0.85-0.90)grade≥A2 and 0.78(95%CI:0.75-0.81)for grade≥A3,which were significantly higher than the AUCs of the single-task groups.Similar findings were observed in the prospec-tive study.Conclusions:The proposed DtCNN improved di-agnostic performance compared with existing fibrosis staging models by including inflammation in the model,which sup-ports its potential clinical application.

关键词： Fibrosis Inflammation Shear wave elastography Chronic hepati-tis B Dual-task convolutional neural network.

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Analytic Initial Relative Orbit Solution for Angles-Only Space Rendezvous Using Hybrid Dynamics Method

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Computer Modeling in Engineering & Sciences 2020年第1期122卷 221-234页

作者： Baichun Gong Shuang Li lili zheng Jinglang Feng Nanjing University of Aeronautics and Astronautics Nanjing210016China Beijing Institute of Aerospace System Engineering Beijing100076China University of Strathclyde GlasgowG11XQScotland

A closed-form solution to the angles-only initial relative orbit determination(IROD)problem for space rendezvous with non-cooperated target is developed,where a method of hybrid dynamics with the concept of virtual formation is introduced to analytically solve the problem.Emphasis is placed on developing the solution based on hybrid dynamics(i.e.,Clohessy-Wiltshire equations and two-body dynamics),obtaining formation geometries that produce relative orbit state observability,and deriving the approximate analytic error covariance for the IROD solution.A standard Monte Carlo simulation system based on two-body dynamics is used to verify the feasibility and evaluate the performance proposed algorithms.The sensitivity of the solution accuracy to the formation geometry,observation numbers is presented and discussed.

关键词： Space rendezvous relative orbit determination angles-only measurement covariance analysis

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Effects of High Temperature Oxidation on Mechanical Properties of Ti_3AlC_2

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Journal of Materials Science & Technology 2017年第6期33卷 596-602页

作者： Xichao Li lili zheng Yuhai Qian Jingjun Xu Meishuan Li Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences University of Chinese Academy of Sciences

The oxidation tests of Ti_3AlC_2 were conducted at 1100 and 1200？C in air for 48 and 360 h, respectively,and the effects of high temperature oxidation on the flexural strength and hardness of Ti_3AlC_2 were investigated. The microstructure, grain size and phase compositions of Ti_3AlC_2 substrate didn＇t change after oxidation, hence the oxide removed Ti_3AlC_2 substrate maintained its initial flexural strength and hardness. However, the flexural strength of oxide retained Ti_3AlC_2 decreased by about 5%. Acoustic emission monitoring indicated that during the process of three-point bending test, the formed Al_2O_3 scale on Ti_3AlC_2 surface fractured firstly in a cleavage manner, then the substrate/oxide interface cracked,and finally the Ti_3AlC_2 substrate fractured. The mechanical degradation was caused by the preferential formation of cracks in brittle Al_2O_3 scale as well as at defective and lacunose grain boundaries of the substrate where stress concentration generated. The mechanical degradation was insensitive to oxidation temperature and time in the present conditions. In addition, the surface hardness increased significantly after oxidation due to the formed hard Al_2O_3 scale on the surface of Ti_3AlC_2 substrate.

关键词： Ti3AlC2 Oxidation Flexural strength Hardness Bending test Acoustic emission

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全媒体时代“大思政课”建构的审视与优化

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北京航空航天大学学报（社会科学版） 2024年第1期37卷 145-151页

作者：王天民郑丽丽北京师范大学马克思主义学院北京100875

“大思政课”是新时代落实立德树人根本任务的新型课程教育理念。伴随全媒体技术同思想政治教育的融合发展,“大思政课”在教育内容、载体、主体、环境上凸显出“全程、全息、全员、全效”(即“四全”)的崭新时代特征。这不仅给传统思... 详细信息

“大思政课”是新时代落实立德树人根本任务的新型课程教育理念。伴随全媒体技术同思想政治教育的融合发展,“大思政课”在教育内容、载体、主体、环境上凸显出“全程、全息、全员、全效”(即“四全”)的崭新时代特征。这不仅给传统思政课教育教学提出了现实挑战,同时也为当前思政课教育教学的优化发展明确了前进方向。全媒体语境下,善用“大思政课”,不仅要把握媒体深度融合的时代背景,明确“大思政课”建构的“四全”特征,还要从凝聚价值共识、加快媒体融合、提升媒介素养、拓展传播格局等路径入手,推动全媒体技术与思政课教育教学深度融合,使“大思政课”无处不在、无时不有,充分发挥思政课在立德树人、铸魂育人中的关键作用。

关键词：全媒体时代 “大思政课” “四全”媒体思政课教育教学课程优化

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Nitrogen addition inhibits total monoterpene emissions in subtropical forest floor of South China

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Soil Ecology Letters 2021年第1期3卷 63-72页

作者： Xingran Huang lili zheng Pingping Guo Zhigang Yi Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China Minjiang River Estuary Wetland National Nature Reserve Administrative Office Fuzhou 350002China

Monoterpenes(MTs)play crucial roles not only in atmospheric chemistry and global climate change but also in soil processes and soil ecology.Elevated nitrogen(N)deposition can influence soil microbial community and litter decomposition,and consequently alters MT fluxes from forest floors and litter.Yet,the responses of soil and litter MT to increased N deposition remain poorly understood and the influences of N addition are sometimes contradictory.In the present study,static chambers were placed in masson pine forest(PF)and in monsoon evergreen broad-leaf forest(BF)at Dinghushan,subtropical China.The preconcentrator-GC–MS was used to analyze the effect of N addition on MT fluxes from the forest floors and litter.The results showed that under control treatment(without N addition),the total MT emission rates were 279.90±137.17 and 102.70±45.36 pmol m^(–2)s^(–1) in the PF and BF floors,respectively,withα-pinene being the largest MT species in the PF and limonene in the BF.α-pinene andβ-pinene emission rates decreased significantly in both forest floors after N addition,whereas a diverse trend was found for limonene and camphene in the PF floor.Furthermore,some MT fluxes showed significant negative correlations with soil respiration and soil temperature.Litter was important in MT fluxes from forest floors and its emission rates were enhanced by N addition.Moreover,different MT response to elevated N was found between the forest floor and litter.This study indicated that the elevated N deposition in the future would inhibit the MT emissions from the subtropical forest floor.

关键词： Biogenic volatile organic compounds Dinghushan Biosphere Reserve Forest floor Little Monoterpene Nitrogen deposition

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Angles-only initial relative orbit determination algorithm for noncooperative spacecraft proximity operations

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Astrodynamics 2018年第3期2卷 217-231页

作者： Baichun Gong Wendan Li Shuang Li Weihua Ma lili zheng Advanced Space Technology Nanjing University of Aeronautics and AstronauticsNanjing210016China National Key Laboratory of Aerospace Flight Dynamics Northwestern Polytechnical UniversityXi’an 710072China Beijing Institute of Aerospace System Engineering Beijing 100076China

This research furthers the development of a closed-form solution to the angles-only initial relative orbit determination problem for non-cooperative target close-in proximity operations when the camera offset from the vehicle center-of-mass allows for range observability.In previous work,the solution to this problem had been shown to be non-global optimal in the sense of least square and had only been discussed in the context of Clohessy–Wiltshire.In this paper,the emphasis is placed on developing a more compact and improved solution to the problem by using state augmentation least square method in the context of the Clohessy–Wiltshire and Tschauner–Hempel dynamics,derivation of corresponding error covariance,and performance analysis for typical rendezvous missions.A two-body Monte Carlo simulation system is used to evaluate the performance of the solution.The sensitivity of the solution accuracy to camera offset,observation period,and the number of observations are presented and discussed.

关键词： initial relative orbit determination angles-only navigation proximity operations rendezvous

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基于特征进化选择随机森林的MCI自动诊断

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计算机应用与软件 2024年第6期41卷 250-256页

作者：高峰郑丽丽顾进广武汉科技大学计算机科学与技术学院湖北武汉430065 武汉科技大学大数据科学与工程研究院湖北武汉430065 湖北省智能信息处理与实时工业系统重点实验室湖北武汉430065 富媒体数字出版内容组织与知识服务重点实验室湖北武汉430065

近年来,作为正常与阿尔茨海默病过渡阶段的轻度认知障碍(Mild Cognitive Impairment,MCI)病症的研究备受关注。但目前的医学MCI人工诊断不仅参考的特征局限性较大,且依靠人工判定,易产生主观上的误差。因此,提出一种基于随机森林的MCI... 详细信息

近年来,作为正常与阿尔茨海默病过渡阶段的轻度认知障碍(Mild Cognitive Impairment,MCI)病症的研究备受关注。但目前的医学MCI人工诊断不仅参考的特征局限性较大,且依靠人工判定,易产生主观上的误差。因此,提出一种基于随机森林的MCI自动诊断方法,通过机器学习的方式,高效准确地判定MCI;同时应用遗传算法更高效地搜索求解模型的最优参数。结果表明,该方法与医学人工诊断方式相比准确率提高约5%,且在求取随机森林的最优参数问题上,与网格搜索相比,遗传算法所用时间约为其1/45。

关键词： MCI 随机森林遗传算法最优参数

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雷芬那辛合成工艺优化

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辽宁师专学报（自然科学版） 2024年第2期26卷 95-103页

作者：魏岚郑丽丽闽西职业技术学院医学护理学院福建龙岩364021

探究雷芬那辛合成新工艺.以4-羟基哌啶盐酸盐为原料,经过亲核取代反应生成4-氯甲酸哌啶盐酸盐,然后与邻氨基联苯经过亲核取代反应生成哌啶-4-基[1,1′-联苯]-2-氨基甲酸酯,再与2-氯-N-甲基-1-胺盐酸盐反应生成1-(2-甲基氨基)乙基)哌啶-4... 详细信息

探究雷芬那辛合成新工艺.以4-羟基哌啶盐酸盐为原料,经过亲核取代反应生成4-氯甲酸哌啶盐酸盐,然后与邻氨基联苯经过亲核取代反应生成哌啶-4-基[1,1′-联苯]-2-氨基甲酸酯,再与2-氯-N-甲基-1-胺盐酸盐反应生成1-(2-甲基氨基)乙基)哌啶-4-基[1,1′-联苯]-2-基氨基甲酸酯,最后经过缩合反应生成雷芬那辛.实验结果表明:合成REV-1的最佳反应溶剂为N-甲基吡咯烷酮,合成REV-2的最佳碱为碳酸钾,合成REV-3的最佳反应温度为80℃,合成REV-4的最佳缩合剂为EDCI/HOBT.所得产品纯度为99.6%,总收率为59.5%,雷芬那辛及中间体经过核磁表征,结构正确.该合成工艺的条件温和、合成率较高,对环境污染较小,是合成雷芬那辛的新选择.

关键词：雷芬那辛慢性阻塞性肺病合成工艺优化

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