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Theoretical and experimental investigation of the resonance responses and chaotic dynamics of a bistable laminated composite shell in the dynamic snap-through mode

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 581-602页

作者： Meiqi WU Pengyu LV Hongyuan LI Jiale YAN huiling duan Wei ZHANG State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering ScienceBIC-ESATCollege of EngineeringPeking UniversityBeijing 100871China Nanchang Innovation Institute of Peking University Nanchang 330096China Department of Mechanics Guangxi UniversityNanning 530004China

The dynamic model of a bistable laminated composite shell simply supported by four corners is further developed to investigate the resonance responses and chaotic *** existence of the 1:1 resonance relationship between two order vibration modes of the system is *** resonance response of this class of bistable structures in the dynamic snap-through mode is investigated,and the four-dimensional(4D)nonlinear modulation equations are derived based on the 1:1 internal resonance relationship by means of the multiple scales *** Hopf bifurcation and instability interval of the amplitude frequency and force amplitude curves are *** discussion focuses on investigating the effects of key parameters,e.g.,excitation amplitude,damping coefficient,and detuning parameters,on the resonance *** numerical simulations show that the foundation excitation and the degree of coupling between the vibration modes exert a substantial effect on the chaotic dynamics of the ***,the significant motions under particular excitation conditions are visualized by bifurcation diagrams,time histories,phase portraits,three-dimensional(3D)phase portraits,and Poincare ***,the vibration experiment is carried out to study the amplitude frequency responses and bifurcation characteristics for the bistable laminated composite shell,yielding results that are qualitatively consistent with the theoretical results.

关键词： bistable laminated composite shell dynamic snap-through mode Hopf bifurcation chaotic dynamics vibration experiment

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Insight into effects of egg- and soybean-derived phosphatidylcholine on non-alcoholic steatosis in mice and HepG2 cells by lipidomics

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Food Science and Human Wellness 2024年

作者： Zhihui Yu Chunyou Liu Yating Gao Haoran Guo huiling duan Lixin Zhang Yisheng Chen College of Food Science and Engineering， Shanxi Agricultural University Institute of Food Nutrition and Safety， Shanxi Agricultural University Department of Food Science and Technology， Guangxi University of Science and Technology

Dietary phosphatidylcholine (PC) is an ideal source of bioactive lipids showing efficacy to alleviate non-alcoholic fatty liver disease (NAFLD). In this study， the lipidomic profiles of nonalcoholic steatosis in mice and HepG2 cells treated with PC isolated from eggs (EPC) and soybean (SPC) were evaluated. EPC and SPC could significantly ameliorate fatty liver disease by down-regulating triglyceride (TG) and diglyceride (DG) levels. Remarkably， EPC exhibited better performance in regulating the hepatic lipid profile leading to decreased PC and TG， ceramides， phosphatidylethanolamine and phosphatidylserine levels. A total of 117 and 20 lipid biomarkers in liver and HepG2 cells involved in glycerophospholipid metabolism were screened out， respectively. The regulatory mechanism of EPC may be attributed to a decrease in the expression of ACACA and SREBP-1c. EPC， via suppressing lipogenic gene expression， which was superior to that of SPC in alleviating nonalcoholic steatosis. Overall， EPC and SPC attenuated HFD-induced NAFLD by improving the hepatic lipid profile. The more significant effect observed with EPC may be attributed to its modulation of glycerophospholipid metabolism.

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改性玉米芯制备太阳能界面蒸发体及其性能分析

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农业工程学报 2024年第9期40卷 236-241页

作者：段慧玲凌童付小强阚阚河海大学电气与动力工程学院南京211100

针对天然生物质材料应用于海水淡化领域,蒸发效率较低、材料容易降解等问题,采用多巴胺对天然玉米芯进行改性处理,以改性玉米芯为基底,在其表面包覆炭黑-纤维素薄膜,制备了一种集光热转换、输水、隔热于一体的太阳能界面蒸发体。对改性... 详细信息

针对天然生物质材料应用于海水淡化领域,蒸发效率较低、材料容易降解等问题,采用多巴胺对天然玉米芯进行改性处理,以改性玉米芯为基底,在其表面包覆炭黑-纤维素薄膜,制备了一种集光热转换、输水、隔热于一体的太阳能界面蒸发体。对改性玉米芯蒸发体的光学吸收性能、输水性能、接触角进行表征,并搭建了室内蒸发试验和户外蒸发试验系统,测试了改性玉米芯的蒸发性能,与天然玉米芯相比,改性玉米芯蒸发体的蒸发速率相对未改性的提升了约10.4%。对改性玉米芯蒸发体进行了30次循环试验,蒸发体均保持稳定的蒸发速率,整个循环测试中蒸发速率波动不超过1%。并且,长期工作后,蒸发体表面没有盐分沉积,没有出现材料软化、降解现象。改性玉米芯蒸发体在海水环境中能够保持良好、稳定的蒸发性能,且能够有效降低海水中的Na^(+)、K^(+)、Mg^(2+)、Ca^(2+)等离子浓度,达到世界卫生组织所规定的饮用标准中的相应限值。改性玉米芯蒸发体的制备方法简单、成本低廉、蒸发性能稳定,为扩展生物质材料在海水淡化领域的应用提供了有效途径。

关键词：改性太阳能玉米芯界面蒸发体输水性能蒸发性能长期工作稳定

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Solid–Liquid Composites with High Impact Resistance

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Acta Mechanica Solida Sinica 2021年第6期34卷 911-921页

作者： Miao Yu Xiying Li Pengyu Lv huiling duan Department of Mechanics and Engineering Science College of EngineeringPeking UniversityBeijing100871China CAPT HEDPS and IFSA Collaborative Innovation Center of MoEPeking UniversityBeijing100871China

Solid–liquid composites(SLCs)with novel thermal/electronic/mechanical properties imparted by programmable and functional liquid inclusions have attracted considerable research interest in recent years,and are widely used in smart electronics and soft *** feasible application of SLCs requires that they exhibit excellent static physical properties as well as dynamic impact resistance to satisfy complex service conditions,such as drops and *** paper examined the impact resistance of SLCs fabricated by using microfluidic 3D *** results of dynamic split-Hopkinson pressure bar(SHPB)tests showed that the performance of the fabricated SLCs improved in terms of energy dissipation and impact resistance compared with pristine *** case of dynamic impact in the strain rates ranging from 100 to 400s−1,the SLC specimen deformed without fracture,and its energy dissipation was dominated by the viscosity of the liquid *** dynamic impact in the strain rates ranging from 500 to 800s−1,the SLC specimen fractured and its energy dissipation was determined by the volume fraction of the liquid ***,the energy dissipation of the SLCs could be tuned by regulating the viscosity and volume fraction of the liquid inclusions to satisfy the requirements of protection against different strain ***,the process of fracture of the SLCs under the dynamic SHPB tests was recorded and analyzed by using a high-speed *** results showed that distributed liquid inclusions changed the paths of crack propagation to enhance energy dissipation in the *** study experimentally verified the enhancement in the energy dissipation of SLCs,and provided design strategies for developing multifunctional SLCs with high impact resistance.

关键词： Solid-liquid composites(SLCs) Impact resistance Dynamic SHPB Energy dissipation Fracturing process

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Theoretical models for irradiation hardening and embrittlement in nuclear structural materials:a review and perspective

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Acta Mechanica Sinica 2020年第2期36卷 397-411页

作者： Xiazi Xiao Dmitry Terentyev Haijian Chu huiling duan Department of Mechanics School of Civil EngineeringCentral South UniversityChangsha 410075China Structural Materials Group Institute of Nuclear Materials ScienceSCK-CEN2400 MolBelgium Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China State Key Laboratory for Turbulence and Complex System Department of Mechanics and Engineering Science College of EngineeringPeking UniversityBeijing 100871China CAPT HEDPS and IFSA CollaborativeInnovation Center of MoEBIC-ESATPeking UniversityBeijing 100871China

The study of irradiation hardening and embrittlement is critically important for the development of next-generation structural materials tolerant to neutron irradiation,and could dramatically affect the approach to the design of components for advanced nuclear *** addition,a growing interest is observed in the field of research and development of irradiation-resistant *** review aims to provide an overview of the theoretical development related to irradiation hardening and embrittlement at moderate irradiation conditions achieved in recent years,which can help extend our fundamental knowledge on nuclear structural *** a general introduction to the irradiation effects on metallic materials,recent research progress covering theoretical modelling is summarized for different types of structural *** fundamental mechanisms are elucidated within a wide range of temporal and spatial *** review closes with the current understanding of irradiation hardening and embrittlement,and puts some perspectives deserving further study.

关键词： Irradiation hardening Irradiation embrittlement Theoretical models Fundamental mechanisms

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VIBRATION OF CANTILEVERS WITH ROUGH SURFACES

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Acta Mechanica Solida Sinica 2009年第6期22卷 550-554页

作者： huiling duan Yahui Xue Xin Yi State Key Laboratory for Turbulence and Complex System CAPT Department of Mechanics and Aerospace Engineering College of Engineering Peking University Beijing 100871 China Division of Engineering Brown University Providence RI 02912 USA

We study the effect of surface roughness on the resonance frequency of micro-cantilever sensors. The analysis demonstrates that surface roughness can enhance, decrease or even annul the effect of surface stress on the resonance frequency, depending on the surface inclination angle and the Poisson ratio of the coating film on the cantilever.

关键词： surface roughness surface stress resonance frequency micro-cantilevers

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Critical velocity in phosphorus exchange processes across the sediment-water interface

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Journal of Environmental Sciences 2013年第10期25卷 1966-1971页

作者： Jun Wan Ze Wang Zhijie Li huiling duan HezhongYuan State Key Laboratory for Turbulence and Complex System Department of Mechanics and Aerospace EngineeringCollege of Engineering Peking University College of Mechanics and Materials Hohai University Research Center for Eco-Environmental Sciences Chinese Academy of Sciences School of Life Sciences Nanjing University

Sediments are ultimate sinks of nutrients in lakes that record the pollution history evolutionary processes, and anthropogenic activities of a lake. However, sediments are considered as inner sources of environmental factor changes such as the variation in hydrodynamic conditions because of the nutrients they release. How does this process happen？ This study investigates a typical nutrient phosphorus （P） exchange among sediment, suspended particle matter （SPM）, and water. Compared with numerical and experimental studies, this study confirms that the critical velocity that occurs at a lower flow rate state exists in the range of 7 to 15 crn/sec. Critical velocity below the critical flow rate promotes the migration of particulate phosphorus （PP） to the SPM. On the other hand, critical velocity above the critical flow rate promotes the release of PP in water.

关键词： abrupt expansion flow critical velocity lake eutrophication phosphorus exchange

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呼吸机下早期雾化吸入布地奈德预防早产儿支气管肺发育不良的疗效观察

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中国当代医药 2024年第16期31卷 73-76,81页

作者：胡小娟胡枫段会玲江西省景德镇市妇幼保健院新生儿科江西景德镇335000

目的探讨呼吸机下早期雾化吸入布地奈德在预防早产儿支气管肺发育不良(BPD)中的应用价值。方法回顾性分析景德镇市妇幼保健院2020年1月至2023年1月收治的60例需呼吸机治疗早产儿的临床资料,按治疗方式的不同分为对照组(30例)与观察组(30... 详细信息

目的探讨呼吸机下早期雾化吸入布地奈德在预防早产儿支气管肺发育不良(BPD)中的应用价值。方法回顾性分析景德镇市妇幼保健院2020年1月至2023年1月收治的60例需呼吸机治疗早产儿的临床资料,按治疗方式的不同分为对照组(30例)与观察组(30例),对照组行无创呼吸机辅助通气治疗,观察组行无创呼吸机辅助通气治疗和呼吸机下早期雾化吸入布地奈德治疗。比较两组的BPD发生情况、治疗效果、肺氧合指标、炎症因子、不良反应。结果治疗组的BPD发生率低于对照组,总吸氧时间、呼吸机使用时间短于对照组,差异有统计学意义(P<0.05)。治疗组治疗48 h后的氧合指数(OI)、肺泡-动脉血氧分压差(PA-aO_(2))、动脉血二氧化碳分压(PaCO_(2))、肿瘤坏死因子-α(TNF-α)、白介素(IL)-6、IL-8、降钙素原(PCT)均低于对照组,动脉血氧分压(PaO2)高于对照组,差异有统计学意义(P<0.05)。两组治疗期间均未出现不良反应。结论呼吸机下早期雾化吸入布地奈德应用于早产儿中能够更好地改善其肺氧合指标,缩短总吸氧时间及呼吸机使用时间,下调TNF-α、IL-6等炎症因子水平,积极预防BPD的发生,且安全可靠,临床应用价值高。

关键词：早产儿支气管肺发育不良呼吸机雾化吸入布地奈德炎症因子肺氧合指标

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Effects of the actuation waveform on the drop size reduction in drop-on-demand inkjet printing

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Acta Mechanica Sinica 2020年第5期36卷 983-989,I0001页

作者： Anas Bin Aqeel Muhammad Mohasan Pengyu Lv Yantao Yang huiling duan SKLTCS and Department of Mechanics and Engineering Science BIC-ESATCollege of EngineeringPeking UniversityBeijing 100871China Department of Mechatronics Engineering National University of Sciences and TechnologyIslamabadPakistan Key Laboratory of High Energy Density Physics Inertial Fusion Sciences and Application Collaborative Innovation Center of Ministry of EducationPeking UniversityBeijing 100871China

In this study the effects of the actuation waveforms on the droplet generation in a drop-on-demand inkjet printing are studied systematically by numerical *** different types of waveforms,namely the unipolar and bipolar actuations,are investigated for three fluids with different physical *** focus on two key parameters,which are the dwell time and the velocity *** the unipolar driving,the ejection velocity and the ejected liquid volume are both increased as the velocity amplitude becomes *** dwell time only has minor effects on both the ejection velocity and the ejected liquid *** ejection velocity decreases significantly for large liquid viscosity,while the influences of viscosity on the ejected liquid volume are much *** different droplet morphologies and the corresponding parameter ranges are *** droplet radius can be successfully reduced to about 40%e of the nozzle exit *** the bipolar waveforms,same droplet morphologies are observed but with shifted boundaries in the phase *** minimal radius of stable droplet produced by the bipolar waveforms is even smaller compared to the unipolar ones.

关键词： Drop-on-demand inkjet printing Actuation waveform optimization Droplet ejection-Printability range

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A grain level model for deformation and failure of ultrafine-grained tungsten

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Science China(Technological Sciences) 2019年第5期62卷 755-761页

作者： REN Ke CHEN LiRong CHENG YangYang WANG JianXiang duan huiling State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering Science College of EngineeringPeking University Key Laboratory of High Energy Density Physics Simulation Center of Applied Physics and Technology BIC-ESAT and IFSA Collaborative Innovation Center of MoE Peking University

Ultrafine-grained tungsten(UFG W) produced by severe plastic deformation technology has many potential applications due to its high strength and ductility. To reveal the mechanism for the high ductility of UFG W, the deformation and failure behaviors of coarse-grained tungsten(CG W) and UFG W have been compared based on a three-dimensional crystal plastic finite element method(CPFEM) simulation. Cohesive element method has been utilized to model the behavior of grain boundaries(GBs). Both plastic deformation in grain interiors and grain boundary opening have been observed in different periods of deformation in UFG W. It is concluded that the high GB density and elongated microstructure in the UFG W suppress crack propagation, decrease the stress concentration and impurity concentration on GBs, therefore enhance the ductility of the material.

关键词： ultrafine grain(UFG) tungsten crystal plasticity interface failure

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