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一种单级控制的高精度指向系统研究

兵工学报 2023年第8期44卷 2477-2485页

作者：杜永刚王雪松王禺林中国空间技术研究院、兰州空间技术物理研究所甘肃兰州730000

实现高指向精度是单级控制指向系统的主要技术难题,消除指向机构的位置浮动环节可提高其指向精度,为此提出一种单级控制的高精度指向系统。采用一种无位置浮动环节的RPS-SPS并联指向机构,通过研究其传动模型和误差消除算法,验证所提指... 详细信息

实现高指向精度是单级控制指向系统的主要技术难题,消除指向机构的位置浮动环节可提高其指向精度,为此提出一种单级控制的高精度指向系统。采用一种无位置浮动环节的RPS-SPS并联指向机构,通过研究其传动模型和误差消除算法,验证所提指向系统原理的正确性,进行了原型机研制和实验测试。测试结果表明:在加载和空载两种状态下,原型机的单轴指向误差均不大于0.004°,其合成指向误差均优于0.006°,其指向稳定时间均小于100 ms,原型机具备了两轴的指向功能,其工作空间可达到两轴±9°。理论和实验研究均证明了该指向系统的可行性和有效性,研究成果为该单级控制的高精度指向系统的工程应用奠定了技术基础。

关键词：指向系统高精度单级控制并联机构误差消除

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A weakly-solvated ether-based electrolyte for fast-charging graphite anode

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Chinese Chemical Letters 2024年第8期35卷 526-532页

作者： Xiao Zhu Yanbing Mo Jiawei Chen Gaopan Liu yonggang Wang Xiaoli Dong Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Institute of New EnergyiChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Fudan UniversityShanghai 200433China

Weakly-solvated electrolytes(WSEs)utilizing solvents with weak coordination ability offer advantages for low-potential graphite anode owing to their facile desolvation process and anions-derived inorganic-rich solid electrolyte interphase(SEI)***,these electrolytes face challenges in achieving a balance between the weak solvation affinity and high ionic conductivity,as well as between rigid inorganic-rich SEI and flexible SEI for long-term ***,we introduce 1,3-dioxolane(DOL)and lithium bis(trifluoromethanesulfonyl)-imide(LiTFSI)as functional additives into a WSE based on nonpolar cyclic ether(1,4-dioxane).The well-formulated WSE not only preserves the weakly solvated features and anion-dominated solvation sheath,but also utilizes DOL to contribute organic species for stabilizing the SEI *** from these merits,the optimized electrolyte enables graphite anode with excellent fast-charging performance(210 mAh/g at 5 C)and outstanding cycling stability(600 cycles with a capacity retention of 82.0%at room temperature and 400 cycles with a capacity retention of 80.4%at high temper-ature).Furthermore,the fabricated LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)||graphite full cells demonstrate stable operation for 140 cycles with high capacity retention of 80.3%.This work highlights the potential of tailoring solvation sheath and interphase properties in WSEs for advanced electrolyte design in graphite-based lithium-ion batteries.

关键词： Weakly-solvated solvent Bisalt ether-based electrolyte Graphite anode NCM||graphite battery Interfacial optimization

Improving mechanical properties and high-temperature oxidation of press hardened steel by adding Cr and Si

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1865-1875页

作者： Rong Zhu yonggang Yang Baozhong Zhang Borui Zhang Lei Li Yanxin Wu Zhenli Mi National Engineering Research Center for Advanced Rolling and Intelligent Manufacturing University of Science and Technology BeijingBeijing 102206China Manufacturing Management Department Ningbo Iron&Steel Co.Ltd.Ningbo 315800China Hunan Valin Lianyuan Iron and Steel Co. Ltd.Loudi 417009China

This work investigated the effect of Cr and Si on the mechanical properties and oxidation resistance of press hardened *** indicated that the microstructure of the Cr-Si micro-alloyed press hardened steel consisted of lath martensite,M_(23)C_(6)carbides,and retained *** retained austenite and carbides are responsible for the increase in elongation of the micro-alloyed *** addition,after oxidation at 930℃for 5 min,the thickness of the oxide scales on the Cr-Si micro-alloyed press hardened steel is less than 5μm,much thinner than 45.50μm-thick oxide scales on *** oxide scales of the Cr-Si micro-alloyed steel are composed of Fe_(2)O_(3),Fe_(3)O_(4),mixed spinel oxide(FeCr_(2)O_(4)and Fe_(2)SiO_(4)),and amorphous SiO_(2).Adding Cr and Si significantly reduces the thickness of the oxide scales and prevents the generation of the FeO *** to the increase of spinel FeCr_(2)O_(4)and Fe_(2)SiO_(4)phase in the inner oxide scale and the amorphous SiO_(2)close to the substrate,the oxidation resistance of the Cr-Si micro-alloyed press hardened steel is improved.

关键词： Cr-Si micro-alloyed press hardened steel mechanical properties oxidation resistance amorphous SiO_(2)

Experiment and modelling of texture and sliding direction dependence on finger friction behavior

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Friction 2024年第9期12卷 1955-1968页

作者： Yuanzhe LI Xue ZHOU Pengpeng BAI Zhonghuan XIANG yonggang MENG Liran MA Yu TIAN State Key Laboratory of Tribology in Advanced Equipment School of Mechanical EngineeringTsinghua UniversityBeijing 100084China

Humans rely on their fingers to sense and interact with external *** the tribological behavior between finger skin and object surface is crucial for various fields,including tactile perception,product appearance design,and electronic skin *** describing finger frictional behavior is always challenging,given the complex structure of the *** this study,the texture and sliding direction dependence of finger skin friction was quantified based on explicit mathematic *** proposed double-layer model of finger skin effectively described the nonlinear elastic response of skin and predicted the scaling-law of effective elastic modulus with contact ***,the skin friction model on textured surface considering adhesion and deformation factors was *** revealed that adhesive term dominated finger friction behavior in daily life,and suggested that object texture size mainly influenced friction-induced vibrations rather than the average friction *** with digital image correlation(DIC)technique,the effect of sliding direction on finger friction was *** was found that the anisotropy in finger friction was governed by the finger’s ratchet pawl structure,which also contributes to enhanced stick-slip vibrations in the distal sliding *** proposed friction models can offer valuable insights into the underlying mechanism of skin friction under various operating conditions,and can provide quantitative guidance for effectively encoding friction into haptics.

关键词： finger friction tactile perception tribological model textured surface sliding direction

Combined effects of climate and land-use changes on the alpha and beta functional diversities of terrestrial mammals in China

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Science China(Life Sciences) 2024年第10期67卷 2224-2233页

作者： Chao Zhang Yumei Li Wei Wang Zexuan Gao Hanqing Liu yonggang Nie Key Laboratory of Animal Ecology and Conservation Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China College of Life Sciences Hebei UniversityBaoding 071002China University of Chinese Academy of Sciences Beijing 100049China

Climate and land-use changes are predicted to impact biodiversity,threatening ecosystem services and ***,their combined effects on the functional diversity of mammals at the regional scale remain unclear,especially at the beta ***,we use projected climate and land-use changes in China to investigate their potential effects on the alpha and beta functional diversities of terrestrial mammals under low-and high-emission *** the current projection,we showed strong positive spatial correlations between functional richness and species *** evenness(FEve),functional specialization(FSpe),and functional originality(FOri)decreased with species richness,and functional divergence(FDiv)increased first and then *** beta diversity was dominated by its nestedness component,in contrast to the taxonomic *** changes in species richness are more strongly influenced by land-use change under the low-emission scenario,while under the high-emission scenario,they are more strongly influenced by climate *** in functional richness(FRic)were inconsistent with those in species richness,with a magnitude of decreases greater than predicted from species ***,mammal assemblages showed potential functional differentiation(FD)across the country,and the trends exceeded those towards taxonomic differentiation(TD).Our findings help us understand the processes underlying biodiversity responses to global changes on multiple facets and provide new insight for conservation plans.

关键词： climate change land-use change functional diversity terrestrial mammals biodiversity conservation

乙烯基笼型倍半硅氧烷/聚丙烯纳米复合材料热降解动力学

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高分子材料科学与工程 2011年第6期27卷 106-109页

作者：曹新鑫高俊刚杜永刚河北大学化学与环境科学学院河北保定071002 河南理工大学材料学院河南焦作454000

用热重分析(TGA)法研究了乙烯基笼型倍半硅氧烷(V-POSS)/聚丙烯纳米复合材料的热降解动力学。采用Kim-Park,Flynn-Wall-Ozawa和Friedman三种方法计算了共混物的降解反应活化能,结果说明,当V-POSS加入质量分数分别为4%、8%、12%和16%、... 详细信息

用热重分析(TGA)法研究了乙烯基笼型倍半硅氧烷(V-POSS)/聚丙烯纳米复合材料的热降解动力学。采用Kim-Park,Flynn-Wall-Ozawa和Friedman三种方法计算了共混物的降解反应活化能,结果说明,当V-POSS加入质量分数分别为4%、8%、12%和16%、升温速率为5℃/min时材料热降解起始温度分别提高了27.1℃、29.3℃、52.6℃和66.9℃,热降解反应活化能E_a提高了10 kJ/mol～50 kJ/mol,反应级数n也随V-POSS加入量增多有所提高,材料热稳定性得到了改善。

关键词：笼型聚倍半硅氧烷聚丙烯热重分析降解动力学

Halogenated Thienoacene Derivatives with Improved Emission Properties

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Chemical Research in Chinese Universities 2024年第4期40卷 699-703页

作者： ZHANG Jingmei MENG Zhihao ZHEN yonggang HE Ping YU Panpan HU Wenping Advanced Innovation Center for Soft Matter Science and Engineering State Key Laboratory of Organic-Inorganic CompositesBeijing University of Chemical TechnologyBeijing100029P.R.China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan430074P.R.China State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian116024P.R.China Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province China West Normal UniversityNanchong637000P.R.China Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education Jiangxi Normal UniversityNanchang330022P.R.China MOE Key Laboratory of Organic Integrated Circuits&Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of ChemistrySchool of SciencesTianjin UniversityTianjin300072P.R.China

Thienoacenes is one of most important groups of semiconducting materials due to the high stability and superior ***,there are scarce studies on the emission properties of thienoacenes to ***,we synthesized fluorinated and chlorinated dibenzo[d,d’]thieno[3,2-b;4,5-b’]dithiophenes(DBTDTs)derivatives F6-DBTDT and Cl6-DBTDT by sulfoxide cyclization,significantly lowering the energy levels relative to the parent compound *** to single crystal structure analysis,F6-DBTDT molecules adopt one-dimensional slipped stacking with closeπ-πinteractions of 3.43Å(1Å=0.1 nm),which is different from the parent compound DBTDT with herringbone stacking ***,the halogenated DBTDT derivatives exhibit enhanced emission properties both in solution and in the solid state,opening up possiblities to improve photoluminescence of thienoacences by halogenation.

关键词： Thienoacene Halogenation Photoluminescence Aggregation structure

Extrusion 3D printing of carbon nanotube-assembled carbon aerogel nanocomposites with high electrical conductivity

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Nano Materials Science 2024年第3期6卷 312-319页

作者： Lukai Wang Jing Men Junzong Feng yonggang Jiang Liangjun Li Yijie Hu Jian Feng Science and Technology on Advanced Ceramic Fibers and Composites Laboratory College of Aerospace Science and EngineeringNational University of Defense Technology109 De Ya RdChangshaHunan410073PR China

Carbon nanotubes(CNTs)with high aspect ratio and excellent electrical conduction offer huge functional improvements for current carbon ***,there remains a major challenge for achieving the on-demand shaping of carbon aerogels with tailored micro-nano structural textures and geometric ***,a facile extrusion 3D printing strategy has been proposed for fabricating CNT-assembled carbon(CNT/C)aerogel nanocomposites through the extrusion printing of pseudoplastic carbomer-based inks,in which the stable dispersion of CNT nanofibers has been achieved relying on the high viscosity of carbomer *** extrusion printing,the chemical solidification through polymerizing RF sols enables 3D-printed aerogel nanocomposites to display high shape fidelity in macroscopic *** from the micro-nano scale assembly of CNT nanofiber networks and carbon nanoparticle networks in composite phases,3D-printed CNT/C aerogels exhibit enhanced mechanical strength(fracture strength,0.79 MPa)and typical porous structure characteristics,including low density(0.220 g cm^(-3)),high surface area(298.4 m^(2)g^(-1)),and concentrated pore diameter distribution(~32.8nm).More importantly,CNT nanofibers provide an efficient electron transport pathway,imparting 3D-printed CNT/C aerogel composites with a high electrical conductivity of 1.49 S cm^(-1).Our work would offer feasible guidelines for the design and fabrication of shape-dominated functional materials by additive manufacturing.

关键词： Carbon aerogel Extrusion 3D printing Carbon nanotube Electrical conductivity Rheology

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助飞运载器螺旋传动失效的机理研究

兵工学报 2023年第7期44卷 2033-2040页

作者：杜永刚王雪松万志华中国空间技术研究院兰州空间技术物理研究所甘肃兰州730000

助飞运载器的螺旋传动缺乏摩擦及温升对其传动的作用机制研究。建立这种螺旋传动机构的热机耦合模型,并利用真实参数模拟传动接触面的热、力学等特性,通过分析应力、温升数据及其与摩擦系数之间的规律,揭示该螺旋传动的失效机制。数值... 详细信息

助飞运载器的螺旋传动缺乏摩擦及温升对其传动的作用机制研究。建立这种螺旋传动机构的热机耦合模型,并利用真实参数模拟传动接触面的热、力学等特性,通过分析应力、温升数据及其与摩擦系数之间的规律,揭示该螺旋传动的失效机制。数值模拟结果表明,该螺旋传动在大载荷的高速摩擦作用下,其传动接触面的温度能快速升至454.3℃,其接触应力可达699.4 MPa,高温降低了接触面的材料强度,因此高速滑动的摩擦力将对接触面造成持续破坏,计算结果和故障现象一致,研究成果也对该传动技术的工程应用提供了理论基础。

关键词：运载器螺旋传动摩擦热失效数值模拟

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