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Unknown system dynamics estimator-based impedance control for lower limb exoskeleton with enhanced performance

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Control Theory and Technology 2024年第1期22卷 56-68页

作者： wenhao Zhang Peng Song Mingying Wu Qiang li Xinmin Mo Pingxin Ji Northwest Institute of Mechanical and Electrical Engineering Xianyang712099ShaanxiChina Xi’an Exo-Smart Dynamics Technology Ltd. Xi’an712046ShaanxiChina Department of Mechanical and Engineering Beijing Institute of TechnologyBeijing100081China

In this article, an unknown system dynamics estimator-based impedance control method is proposed for the lower limb exoskeleton to stimulate the tracking flexibility with the terminal target position when suffering parametric inaccuracies and unexpected disturbances. To reinforce the robust performance, via constructing the filtering operation-based dynamic relation, i.e., invariant manifold, the unknown system dynamics estimators are employed to maintain the accurate perturbation identification in both the hip and knee subsystem. Besides, a funnel control technique is designed to govern the convergence process within a minor overshoot and a higher steady-state precision. Meanwhile, an interactive complaint result can be obtained with the aid of the impedance control, where the prescribed terminal trajectory can be adjusted into the interaction variable-based target position by the force–position mapping, revealing the dynamic influence between the impedance coefficient (stiffness and damping) and the adjusted position magnitude. A sufficient stability analysis verifies the ultimately uniformly bounded results of all the error signals, and even the angle errors can be regulated within the predefined funnel boundary in the whole convergence. Finally, some simulations are provided to demonstrate the validity and superiority including the enhanced interaction flexibility and robustness.

关键词： Trajectory tracking Invariant manifold Funnel control Impedance control Lower limb exoskeleton

塔里木盆地塔北隆起英买力地区陆相原油分子地球化学特征及来源

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长江大学学报（自然科学版） 2024年第3期21卷 20-25页

作者：昌伦杰赵海涛李文浩易珍丽李斌王民卢双舫应俊锋中国石油塔里木油田分公司勘探开发研究院新疆库尔勒841000 中国石油大学(华东)地球科学与技术学院山东青岛266580

尽管塔北隆起英买力地区陆相油气获得了重要突破,但油气成因类型及油源尚存在争议,根据分子地球化学及同位素参数,通过油源对比研究,明确了原油成因类型及来源。研究结果表明:研究区原油主要分为两种类型,其中第Ⅰ类原油广泛分布在除YM2... 详细信息

尽管塔北隆起英买力地区陆相油气获得了重要突破,但油气成因类型及油源尚存在争议,根据分子地球化学及同位素参数,通过油源对比研究,明确了原油成因类型及来源。研究结果表明:研究区原油主要分为两种类型,其中第Ⅰ类原油广泛分布在除YM21井和YM46井外的其他地区,三环萜烷多以C_(21)为主峰,C_(24)四环萜烷含量相对较高,C_(24)Tet/C_(26)TT介于1.0~2.0,重排藿烷含量相对较低,该类原油与库车坳陷黄山街组烃源岩生物标志物特征类似;第Ⅱ类原油分布在YM21井和YM46井,原油中三环萜烷通常以C_(19)为主峰,C_(24)四环萜烷含量较高,明显高于第Ⅰ类原油,C_(24)Tet/C_(26)TT约为3,C_(30)重排藿烷/C_(30)藿烷约为0.5,该类原油与恰克马克组烃源岩生物标志物特征较为接近。此外,第Ⅰ类原油具有相对较轻碳同位素值,主要分布在-29.6‰~-28.2‰,第Ⅱ类原油具有相对偏重的碳同位素值,其同位素值约为-27‰,同位素特征也揭示第Ⅰ类原油和第Ⅱ类原油分别来源于黄山街组和恰克马克组烃源岩。

关键词：生物标志化合物油源对比原油碳同位素英买力地区塔北隆起

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Effects of biodegradable mulching films on soil hydrothermal conditions and yield of drip-irrigated cotton(Gossypium hirsutum L.)

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International Journal of Agricultural and Biological Engineering 2022年第6期15卷 153-164页

作者： Dongwang Wang Zhenhua Wang Hongwei Ding Bo Zhou Jinzhu Zhang wenhao li Haiqiang li Yam P.Dhital Tianyu Wang Rui Zong College of Water Conservancy&Architectural Engineering Shihezi UniversityShihezi 832000XinjiangChina Key Laboratory of Modern Water-saving Irrigation of Xinjiang Production&Construction Group Shihezi 832000XinjiangChina Key Laboratory of Northwest Oasis Water-Saving Agriculture Ministry of Agriculture and Rural AffairsChina

The pollution of cotton fields by residual films is serious on ground that has been subjected to long-term drip irrigation in Xinjiang,China,and biodegradable mulches are therefore advocated as an alternative to plastic *** this study the mulching with biodegradable films under drip irrigation conditions in the extremely arid region of Xinjiang was investigated to determine the effects on soil hydrothermal conditions and cotton(Gossypium hirsutum L.)yield over two consecutive years(2019-2020)using plastic mulch made from polyethylene(PE)film and four types of biodegradable films,including black opaque oxidation-biodegradable film(M1),colorless transparent oxidation-biodegradable film(M2),black opaque fully biodegradable film(M3)and white translucent fully biodegradable film(M4),which had different levels of biodegradability(*** degradation times and rates).The biodegradability,soil water contents,soil temperatures and cotton yields were compared between the degradable(M1 to M4)and PE *** results indicated that M2 was degraded the quickest and showed the highest degree of degradation compared with the other degradable films and PE *** degradation rates of the various mulching films were ranked in a descending order as M2,M4,M1,M3 and PE,but the PE mulch exhibited the best performance in terms of soil water and heat conservation throughout the growth *** soil heat preservation and moisture conservation performance under biodegradable films mulching at the cotton seedling stage and budding stage was similar to that of PE *** average soil temperature at a depth of 5 cm under mulching with the degradable films was 2.66°C-5.06°C(p<0.05)lower than that under traditional PE films at the flowering *** the late stage of cotton growth,the water content of shallow soil mulched with PE film was better for plant grown than that under the biodegradable *** effect of film degradation on the shallow soil water content was much greater

关键词： arid environment biodegradable films cotton yield oasis agroecosystem soil temperature soil moisture

Achieving high thermoelectric performance through carrier concentration optimization and energy filtering in Cu_(3)SbSe_(4)-based materials

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Journal of Materiomics 2022年第5期8卷 929-936页

作者： Sitong Wei Boyi Wang Zipei Zhang wenhao li Lu Yu Shikai Wei Zhen Ji Weiyu Song Shuqi Zheng College of New Energy and Materials China University of PetroleumBeijing102249China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing100049China College of Science China University of PetroleumBeijing102249China

The previous works commonly adjust the carrier concentration through acceptor doping,but at the same time,the decrease of the Seebeck coefficient limits the further improvement of electrical properties in Cu_(3)SbSe_(4)-based *** this work,a microwave-assisted hydrothermal synthesis method was used to synthesize Cu_(3)SbSe_(4)/TiO_(2) hollow *** of TiO_(2) participates in the reaction,replaces the Sb site of Cu_(3)SbSe_(4) to form holes,and the rest is dispersed in the matrix in the form of the second *** first-principles calculations reveal that the doping of Ti significantly changes the band structure and phonon spectrum,thereby regulating carrier concentration while increasing phonon *** addition,experimental results show that the energy filtering effect generated by the extra-mixed TiO_(2) nano particles,which suppresses the decrease of Seebeck coefficient by acceptor ***,the highest average power factor 897.5 mW m^(-1) K^(-2) and the zT peak value of 0.70 can be obtained in Cu_(3)SbSe_(4)/6%TiO_(2) sample at 298e623 *** work provides a new sight to improve the thermoelectric properties in Cu_(3)SbSe_(4) through carrier concentration regulation and nano-phase composition.

关键词： Cu_(3)SbSe_(4)/Nano-TiO_(2) Energy filtering effect Thermoelectric Synergistic modulation

Differences in leaf cuticular wax induced by whole-genome duplication in autotetraploid sour jujube

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Horticultural Plant Journal 2024年第1期10卷 66-76页

作者： Meng li Chenxing Zhang Lu Hou Xinru liu Hanqing Zhao Xiaoming Pang wenhao Bo Yingyue li National Engineering Research Center of Tree Breeding and Ecological Restoration College of Biological Sciences and TechnologyBeijing Forestry UniversityBeijing 100083China Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of EducationCollege of Biological Sciences and TechnologyBeijing Forestry UniversityBeijing 100083China The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration Beijing Forestry UniversityBeijing 100083China

Drought-resistant plants exhibit strong water retention *** this regard,the autotetraploid sour jujube leaves exhibit better water retention than diploid *** comparisons and physiological comparisons of diploid and autotetraploid leaves showed that the autotetraploid leaves had thicker leaf cuticles and more leaf wax accumulation than the diploid leaves,which could reduce cuticle permeability and improve the drought tolerance of *** this study,the cuticular wax crystalloids on the adaxial and abaxial sides of young and mature jujube leaves were observed in the two ploidy types,and unique cuticular wax crystalloids covering a large area of the cuticle on autotetraploid sour jujube leaves may provide an advantage in reducing leaf non-stomata transpiration and improving plant drought *** on the transcriptome,115 differentially expressed genes between diploids and autotetraploids were further analyzed and found to be involved in the accumulation of cuticular wax components,including terpenoids,fatty acids,and lipids,as well as ABC transporter and wax biosynthetic ***,14 genes differentially expressed between glossy autotetraploid leaves and nonglossy diploid leaves,such as LOC107414787,LOC107411574 and LOC107413721,were screened as candidate genes by qRT-PCR *** findings provided insights into how polyploidization improved drought tolerance.

关键词： Autotetraploid Jujube Drought tolerance Cuticular wax RNA-seq

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Some aspects of excellent marine source rock formation:implications on enrichment regularity of organic matter in continental margin basins

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Chinese Journal Of Geochemistry 2015年第1期34卷 47-54页

作者： wenhao li Zhihuan Zhang Youchuan li School of Geosciences China University of Petroleum Research Institute of Unconventional Petroleum and Renewable Energy China University of Petroleum State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum CNOOC Research Institute

Through the analysis of ocean organisms, the distribution characteristics and enrichment of organic matters in modern marine sediments and ancient marine strata, this paper shows that the main factors influencing the formation of excellent marine source rocks are the paleoclimate, biologic productivity, terrestrial organic matter, oxidation–reduction environment, sedimentation rate, and the type of the basin. In addition to those factors,high biologic productivity or high content of terrestrial organic matter input is a requirement for the enrichment of the organic matter in a marine environment. Reducing environment was favorable for organic matter accumulation and preservation in depositing and early diagenesis stage, which is an important element for the formation of high-quality marine source rocks. Paleoclimate also influences the marine source rocks formation, as humid subtropical and tropical climates are the most favorable regimes for the formation of marine source rocks. Wind transports some vascular plant materials into the marine environment. Furthermore, upwellings driven by steady wind can cause high biologic productivity, thus formingorganic-C-rich mud. Suitable sedimentation rate is beneficial for marine organic matter accumulation. Moreover, the type of the basin also plays an important role in the development of marine source rocks. Silled basins with a positive water balance often act as nutrient traps, thus enhancing both productivity and organic matter preservations, while in open oceans, organic matter enrichment in sediments has just been found in the oxygen minimum layers.

关键词：海相烃源岩大陆边缘盆地富集规律有机物氧化还原环境生物生产力海洋沉积物海洋生物

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丙烯酸酯类无氟防污整理剂的合成及在羊毛织物上的应用

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印染 2024年第6期50卷 48-52页

作者：郭亚丽丁凤美王庆淼何瑾馨王平陈加友李文豪邢志奇东华大学化学与化工学院国家染整工程技术研究中心上海201620 雅戈尔集团股份有限公司浙江宁波315153

为提升羊毛织物的防污性能,首先采用酸性蛋白酶对织物进行预处理来增加粗糙度,然后以甲基丙烯酰氧丙基三(三甲基硅氧烷基)硅烷(M3T)与甲基丙烯酸十八烷酯(SMA)为功能单体,合成无氟防污整理剂MS,并将其应用于羊毛织物的防污整理。整理后... 详细信息

为提升羊毛织物的防污性能,首先采用酸性蛋白酶对织物进行预处理来增加粗糙度,然后以甲基丙烯酰氧丙基三(三甲基硅氧烷基)硅烷(M3T)与甲基丙烯酸十八烷酯(SMA)为功能单体,合成无氟防污整理剂MS,并将其应用于羊毛织物的防污整理。整理后织物的水接触角由118.6°提高为150.5°,花生油润湿时间由4 s提高至3 min,具有良好的防水性能与防油污性能,且整理后织物经20次洗涤后接触角仍有141.7°,经过3000次摩擦后接触角为139.7°,具有良好的耐洗性与耐摩擦性。

关键词：功能整理蛋白酶处理无氟防污整理剂乳液聚合羊毛织物

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空心刨花板填充免漆木质复合门门扇生产工艺浅析

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中国人造板 2024年第7期31卷 23-26页

作者：李文浩王泽伟张国梁常亮孙照斌胡继文河北农业大学机电工程学院河北保定071001 河北农业大学林学院河北保定071001 永清霍尔茨门业有限公司河北廊坊065600

介绍免漆木质复合门门扇的生产工艺流程,阐述其生产所用材料的部分尺寸、性能参数,分析空心刨花板铺装方式对门扇变形的影响,以期为免漆木质复合门门扇的生产提供参考。

关键词：空心刨花板木质复合门生产工艺

Microstructure Evolution and Mechanical Properties of Friction Stir Welded Al-Cu-li Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第5期37卷 855-871页

作者： Peng Chen wenhao Chen Jiaxin Chen Zhiyu Chen Yang Tang Ge liu Bensheng Huang Zhiqing Zhang School of New Energy and Materials Southwest Petroleum UniversityChengdu 610500China Sichuan Provincial Engineering Research Center of Advanced Materials Manufacturing Technology for Shale Gas High-Efficient Exploitation Southwest Petroleum UniversityChengdu 610500China College of Materials Science and Engineering Chongqing UniversityChongqing 400045China School of Mechatronic Engineering Southwest Petroleum UniversityChengdu 610500China School of Robot Engineering Yangtze Normal UniversityChongqing 408100China

The investigation concentrates on friction stir welded(FSW)Al-Cu-li alloy concerning its local microstructural evolution and mechanical *** grain features were characterized by electron back scattered diffraction(EBSD)technology,while precipitate characterization was conducted by using transmission electron microscopy(TEM)aligned along[011]Al and[001]Al zone *** mechanical properties are evaluated through micro-hardness and tensile *** can be found that nugget zones exhibit finely equiaxed grains evolved through complete dynamic recrystallization(DRX),primarily occurring in continuous dynamic recrystallization(CDRX)and discontinuous dynamic recrystallization(DDRX).In the thermal-mechanically affected zone(TMAZ),numerous sub-structured grains,exhibiting an elongated morphology,were created due to partial DRX,signifying the dominance of CDRX,DDRX,and geometric dynamic recrystallization(GDRX)in this region.T_(1)completely dissolves in the nugget zone(NZ)leading to the formation of Guinier-Preston zones and increase ofδ′,β′and S′.Conversely,T_(1)partially solubilizes in TMAZ,the lowest hardness zone(LHZ)and heat affected zone(HAZ),and the residual T_(1)undergoes marked coarsening,revealing various T_(1)*** solubilization and coarsening of T_(1)are primary contributors to the degradation of hardness and strength.θ′primarily dissolves and coarsens in NZ and TMAZ,whilst this precipitate largely coarsens in HAZ and LHZ.σ,TB,grain boundary phases(GBPs)and precipitate-free zone(PFZ)are newly generated during FSW.σexists in the TMAZ,LHZ and HAZ,whereas TB nucleates in *** and PFZ mostly develop in LHZ and HAZ,which can cause strain localization during tensile deformation,potentially leading to LHZ joint fracture.

关键词： Al-Cu-li alloy Friction stir welding Microstructure evolution Mechanical properties