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A novel adaptive harmonic balance method with an asymptotic harmonic selection

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Applied Mathematics and Mechanics(English Edition) 2023年第11期44卷 1887-1910页

作者： Rongzhou LIN lei HOU Yi CHEN yuhong JIN N.A.SAEED Yushu CHEN School of Astronautics Harbin Institute of TechnologyHarbin 150001China Department of Physics and Engineering Mathematics Faculty of Electronic EngineeringMenoufia UniversityMenouf 32952Egypt Department of Automation Biomechanicsand MechatronicsFaculty of Mechanical EngineeringLodz University of TechnologyLodz 90924Poland Mathematics Department Faculty of ScienceGalala UniversityGalala 43511Egypt

The harmonic balance method(HBM)is one of the most widely used methods in solving nonlinear vibration problems,and its accuracy and computational efficiency largely depend on the number of the harmonics *** adaptive harmonic balance(AHB)method is an improved HBM *** paper presents a modified AHB method with the asymptotic harmonic selection(AHS)*** new harmonic selection procedure selects harmonics from the frequency spectra of nonlinear terms instead of estimating the contribution of each harmonic to the whole nonlinear response,by which the additional calculation is avoided.A modified continuation method is proposed to deal with the variable size of nonlinear algebraic equations at different values of path parameters,and then all solution branches of the amplitude-frequency response are *** experiments are carried out to verify the performance of the AHB-AHS *** typical nonlinear dynamic equations with different types of nonlinearities and excitations are chosen as the illustrative *** with the classical HBM and Runge-Kutta methods,the proposed AHB-AHS method is of higher accuracy and better *** AHB-AHS method proposed in this paper has the potential to investigate the nonlinear vibrations of complex high-dimensional nonlinear systems.

关键词： harmonic balance method(HBM) adaptive harmonic balance(AHB)method harmonic selection nonlinear vibration multi-frequency excitation

牛庄洼陷南斜坡沙河街组原油成因类型的多参数聚类分析

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石油实验地质 2013年第4期35卷 457-463页

作者：宋成鹏罗晓容郝雪峰向立宏刘克奇张立宽雷裕红程明杨彬中国石油勘探开发研究院北京100083 中国科学院地质与地球物理研究所油气资源研究重点实验室北京100029 中国石油化工股份有限公司胜利油田分公司地质科学研究院山东东营257015

通过牛庄洼陷源岩抽提物异戊二烯烃、单体烃碳同位素和甾、萜烷化合物等多种地化参数的对比,优选出植烷、伽马蜡烷、升藿烷系列、甲藻甾烷和4-甲基甾烷等生标化合物构成源岩特征指纹参数,采用聚类分析方法对沙河街组原油成因类型进行了... 详细信息

通过牛庄洼陷源岩抽提物异戊二烯烃、单体烃碳同位素和甾、萜烷化合物等多种地化参数的对比,优选出植烷、伽马蜡烷、升藿烷系列、甲藻甾烷和4-甲基甾烷等生标化合物构成源岩特征指纹参数,采用聚类分析方法对沙河街组原油成因类型进行了研究,结果表明该区原油可以划分为3类:Ⅰ类原油与沙三源岩聚为一类,具有低植烷丰度、低伽马蜡烷丰度、低C35升藿烷丰度、低甲藻甾烷丰度和低4-甲基αααC29甾烷丰度的"五低"特点,体现了来源于弱氧化、低盐度环境下形成的沙三下亚段源岩的地化特征;Ⅱ类原油与沙四源岩聚为一类,具有高植烷丰度、高伽马蜡烷丰度、高C35升藿烷丰度、高甲藻甾烷丰度和高4-甲基αααC29甾烷丰度的"五高"特点,体现了来源于强还原、高盐度环境下形成的沙四上亚段源岩地化特征;Ⅲ类原油和沙三、沙四源岩没有显著的聚类关系,也与孔店组原油和源岩地化特征不同,而其主要聚类参数的均值均处于沙三下亚段、沙四上亚段源岩的均值范围之间,推测可能为2套源岩生成原油的混合油。

关键词：烃源岩生物标志化合物原油类型聚类分析牛庄洼陷东营凹陷渤海湾盆地

柴达木枸杞的农业气象观测方法研究与标准制定

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中国农学通报 2020年第15期36卷 81-86页

作者：颜亮东赵梦凡梁志勇雷玉红杨殷胜青海省气象科学研究所西宁810001 青海省防灾减灾重点实验室西宁810001 青海省格尔木市气象局青海格尔木816099

依据连续性、广泛适用性和可操作性原则,制定《柴达木枸杞农业气象观测方法》,结合《农业气象观测规范》和柴达木地区枸杞观测试验,制定观测及评定枸杞各个发育期和生长状况、生长量和产量、相关农业气象灾害和病虫害等方法与标准。同... 详细信息

依据连续性、广泛适用性和可操作性原则,制定《柴达木枸杞农业气象观测方法》,结合《农业气象观测规范》和柴达木地区枸杞观测试验,制定观测及评定枸杞各个发育期和生长状况、生长量和产量、相关农业气象灾害和病虫害等方法与标准。同时根据实际观测中存在的问题,提出低温冻害、病虫害危害等特殊情况下的解决方法,进一步优化观测标准,实现柴达木地区枸杞气象观测、科研、服务等相关工作的规范性和理论性,以期为高产优质的枸杞特色农业生产提供科技支撑。

关键词：枸杞农业气象观测规范柴达木建议标准制定

Environment-friendly synthesis of N-phenylpiperidine from aniline and 1,5-pentanediol overγ-Al_2O_3 catalyst

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Journal of Natural Gas Chemistry 2008年第4期17卷 383-386页

作者： Wei Tan Chunmei Li Jiacong Zheng lei Shi Qi Sun yuhong He Institute of Chemistry for Functionalized Materials Liaoning Normal University Dalian 116029 Liaoning China Liaoyuan Health School Liaoyuan 136200 Jilin China

An efficient environment-friendly synthesis of N-phenylpiperidine was developed from aniline and 1,5-pentanediol over γ-Al2O3 catalyst under atmospheric pressure. The conversion of 1,5-pentanediol reached 97% and the selectivity for N-phenylpiperidine attained 94%. The structure of the catalyst was characterized by NH3-TPD and BET. The influences of calcination temperature of the catalyst and reaction temperature on activity and selectivity of the catalyst were investigated.

关键词： γ-Al2O3 catalyst N-phenylpiperidine aniline 1,5-pentanediol

Macroscale superlubricity under ultrahigh contact pressure in the presence of layered double hydroxide nanosheets

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Nano Research 2022年第5期15卷 4700-4709页

作者： Kunpeng Wang lei Liu Aisheng Song Tianbao Ma Hongdong Wang Jianbin Luo yuhong Liu State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China School of Mechatronic Engineering Shanghai UniversityShanghai 200444China

It is difficult to achieve macroscale superlubricity under high contact pressures and high normal *** double hydroxide(LDH)nanoadditives were introduced into an ionic liquid alcohol solution(IL(as))with contact pressures up to 1.044 GPa,which resulted in a friction coefficient(COF)of 0.004 and a robust superlubricity state lasting for 2 *** with the LDH particles(LDH-Ps)with ca.90-nm widths and 18-nm thickness,micron-scale LDH nanosheet(LDH-N)additives with ca.1.5-pm width and 6-nm thickness increased the load-bearing capacity by approximately three times during *** lubricant film thickness and the ultrathin longitudinal dimension of the LDH-N additives did not influence the continuity of the fluid film on the contact *** improvements resulted from the protective adsorption layer and ion distribution formed on the contact interface,as revealed by detailed surface analyses and simulation *** particular,the sliding energy barrier and Bader charge calculation revealed that weak shear sliding between the nanosheet and the solid surface formed easily and the anions in the liquid adsorbed on the solid surface exhibited electrostatic repulsion forces,which generated stable tribological properties *** research provides a novel method for obtaining macroscale superlubricity for practical industrial applications.

关键词： macroscale superlubricity layered double hydroxide(LDH)nanosheets ionic liquid high pressure heterostructure

宁夏枸杞在柴达木高寒地区的适应性及与气象因子的关系

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中国农学通报 2019年第31期35卷 83-88页

作者：祁贵明雒维萍雷玉红李海凤管吉龙格尔木市气象局青海格尔木816099 格尔木市农业科学研究所青海格尔木816099 青海省都兰县诺木洪气象站青海都兰816102

研究宁夏枸杞(Lycium barbarum L)在高寒地区的适应性对其推广应用具有重要的经济和实践价值。笔者选择柴达木高寒地区1300 m2的宁夏枸杞种植地,利用连续观测3年的宁夏枸杞发育期、产量因素和产量结构,结合当地气象资料探究宁夏枸杞在... 详细信息

研究宁夏枸杞(Lycium barbarum L)在高寒地区的适应性对其推广应用具有重要的经济和实践价值。笔者选择柴达木高寒地区1300 m2的宁夏枸杞种植地,利用连续观测3年的宁夏枸杞发育期、产量因素和产量结构,结合当地气象资料探究宁夏枸杞在高寒地区的适应性。结果表明:宁夏枸杞在柴达木高寒地区的发育时间为181天;平均产量为426.52 g/m^2;产量结构为:老眼枝果>夏果>秋果。枸杞产量与气象因子的Pearson相关显示:局域环境中枸杞产量与气象因子的关系均不显著(P>0.05),推测该区域枸杞产量主要受灌溉驱动。综合表明,宁夏枸杞在柴达木高寒地区的适应性较好,但需要合理经营管理。

关键词：宁夏枸杞柴达木高寒地区适应性产量结构气象因子

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巡逻机器人底盘防御策略优化

机械制造 2024年第11期62卷 10-15页

作者：雷羽虹杭晨旋游心懿王宇哲杨涛梁冬泰彭成斌宁波大学信息科学与工程学院浙江宁波315211 宁波大学机械工程与力学学院浙江宁波315211

基于四轮竞赛机器人模型结构,对巡逻机器人底盘防御策略进行优化。针对受到冲击后的防御模式,优化冲击后姿态控制算法,提出底盘冲击摆动控制模式。底盘冲击摆动控制模式实现底盘在保持既定运动方向的同时自旋转一定角度避开冲击,并且通... 详细信息

基于四轮竞赛机器人模型结构,对巡逻机器人底盘防御策略进行优化。针对受到冲击后的防御模式,优化冲击后姿态控制算法,提出底盘冲击摆动控制模式。底盘冲击摆动控制模式实现底盘在保持既定运动方向的同时自旋转一定角度避开冲击,并且通过坐标系变换,保持底盘前进方向与云台朝向一致。对底盘冲击摆动控制模式和小陀螺模式进行云台稳定性测试、底盘功率测试和血量对比,采用底盘冲击摆动控制模式,在直线运动时,云台俯仰角波动角度更小;在受到持续打击时,装甲受到弹丸攻击的血量伤害更低,底盘防御策略更优。通过研究确认,优化底盘防御策略提出的底盘冲击摆动控制模式在巡逻机器人上应用具有优势。

关键词：巡逻机器人底盘防御策略优化

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Mental health status of students’parents during COVID-19 pandemic and its influence factors

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General Psychiatry 2020年第4期33卷 179-187页

作者： Mengting Wu Wenyan Xu yuhong Yao lei Zhang lei Guo Juan Fan Jue Chen Shanghai Mental Health Center Shanghai Jiao Tong University School of MedicineShanghaiChina School of Social Development and Public Policy Fudan UniversityShanghaiChina Mental Health Education and Counseling Center Tongji UniversityShanghaiChina

Background During the outbreak of COVID-19,the national policy of home quarantine may affect the mental health of ***,few studies have investigated the mental health of parents during the COVID-19 *** To investigate the depression,anxiety and stress of the students'parents during the COVID-19 pandemic,and to explore the influence factors,especially the influence of social support and family-related *** The Generalised Anxiety Disorder-7,Patient Health Questionnaire-9,Perceived Stress Scale-10 and Social Support Rating Scale were applied to 1163 parents to measure the parents'depression,anxiety,stress and social ***(1)The detection rates of depression and anxiety in parents were 6.1%and 4.0%.The depression,anxiety and perceived stress of parents in central China were significantly higher than those in non-central *** anxiety of college students'parents was lower than that of parents of the primary,middle and high school *** depression,anxiety and perceived stress of parents with conflicts in the family were significantly higher than those with a harmonious *** factors that influence parents’depression,anxiety and perceived stress include marital satisfaction,social support,parents*history of mental illness and parenting style,etc.(2)The regression analysis results showed that perceived stress,social support,marital satisfaction,family conflicts,child's learning stage as well as parents'history of mental illness had significant effects on parents'anxiety and *** During the COVID-19 pandemic,the mental health of parents was affected by a variety of *** marital relationships,good social support,family harmony and parents without a history of mental illness may be protective factors for parents*mental health,while perceived stress and child in middle or high school are risk factors for parents’mental health.

关键词： harmony parents protective

Spatiotemporal Evolution Characteristics Study on the Precipitation Infiltration Recharge over the Past 50 Years in the North China Plain

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Journal of Earth Science 2015年第3期26卷 416-424页

作者： Suhua Meng Jin Liu Zhaoji Zhang Ting lei Yong Qian Yasong Li yuhong Fei Institute of Hydrogeology and Environmental Geology Chinese Academy of Geological Sciences

The spatiotemporal evolution characteristics of precipitation infiltration recharge during the past 50 years are discussed in this paper. This research is significant for groundwater resource rational utilization. The distribution of precipitation infiltration recharge coefficients in the 1960 s, 1980 s, and 2000 s can be obtained using unsaturated zone lithology and depth to water table at different times. The amount of precipitation infiltration recharge in the 1960 s, 1980 s, and 2000 s can be calculated using precipitation infiltration recharge coefficients and precipitation data from the Ministry of Water Resources of China. Results show that the change in the precipitation infiltration recharge coefficient is closely related to the water table decrease. From the 1960 s to the 1980 s, the precipitation infiltration recharge coefficient clearly increased in all units. From the 1980 s to the 2000 s, the value slightly increased in the ancient Yellow River alluvial-proluvial and eastern alluvial-marine plains and slightly decreased in the piedmont alluvial-proluvial and central alluvial-lacustrine plains. The piedmont alluvial-proluvial and ancient Yellow River alluvial-proluvial plains exhibited a large precipitation infiltration recharge coefficient for the coarse lithology. The amounts of precipitation infiltration recharges were 16.23×109（1960s）, 19.11×109（1980s）, and 19.42×109 m3/a（2000s）. The amount of precipitation infiltration recharge increased from the 1960 s to the 1980 s then decreased from the 1980 s to the 2000 s in the piedmont alluvial-proluvial and the central alluvial-lacustrine plains. However, this value increased from the 1960 s to the 2000 s in the ancient Yellow River alluvial-proluvial and eastern alluvial-marine plains.

关键词： North China Plain precipitation infiltration recharge evolution characteristics water table