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Engineering 2024年第8期39卷 244-252页

作者： Gaohui liu Jie Guan Xianfeng Wang Jianyong Yu Bin Ding Shanghai Frontier Science Research Center of Advanced Textiles College of TextilesDonghua UniversityShanghai 201620China College of Materials Science and Engineering Qingdao UniversityQingdao 266071China

Biodegradable polylactic acid(PLA)melt-blown nonwovens are attractive candidates to replace nondegradable polypropylene melt-blown ***,it is still an extremely challenging task to prepare PLA melt-blown nonwovens with sufficient mechanical properties for practical ***,we report a simple strategy for the large-scale preparation of biodegradable PLA/poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)melt-blown nonwovens with high strength and excellent *** this process,a small amount of PHBV is added to PLA to improve the latter’s crystallization rate and *** addition,when the PHBV content increases from 0 to 7.5 wt%,the diameters of the PLA/PHBV melt-blown fibers decrease significantly(with the proportion of nanofibers increasing from 7.7%to 42.9%).The resultant PLA/PHBV(5 wt%PHBV)melt-blown nonwovens exhibit the highest mechanical *** tensile stress,elongation,and toughness of PLA/PHBV(5 wt%PHBV)melt-blown nonwovens reach 2.5 MPa,45%,and 1.0 MJm3,*** importantly,PLA/PHBV melt-blown nonwovens can be completely degraded into carbon dioxide and water after four months in the soil,making them environmentally friendly.A general tensile-failure model of melt-blown nonwovens is proposed in this study,which may shed light on mechanical performance enhancement for nonwovens.

关键词： PLA PHBV Melt-blown Biodegradable Strength Toughness

An Approximation Algorithm for the Parallel-Machine Customer Order Scheduling with Delivery Time and Submodular Rejection Penalties

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Journal of the Operations Research Society of China 2024年第2期12卷 495-504页

作者： Hong-Ye Zheng Suo-Gang Gao Wen liu Bo Hou School of Mathematical Sciences Hebei Normal UniversityShijiazhuang 050024HebeiChina

In this paper,we consider the parallel-machine customer order scheduling with delivery time and submodular rejection *** this problem,we are given m dedicated machines in parallel and n customer *** order has a delivery time and consists of m product types and each product type should be manufactured on a dedicated *** order is either rejected,in which case a rejection penalty has to be paid,or accepted and manufactured on the m dedicated *** objective is to find a solution to minimize the sum of the maximum delivery completion time of the accepted orders and the penalty of the rejected orders which is determined by a submodular *** design an LP rounding algorithm with approximation ratio of n+1 for this problem.

关键词： Order scheduling Delivery time-Submodular rejection penalty:Approximationalgorithm

Alternative technology for the recovery of butyl acetate with low concentration:high capacity adsorbent and high efficiency adsorption

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Green Chemical Engineering 2024年第2期5卷 236-244页

作者： Chi Ma lihong Zhao Zhengxin Mao Hao Su Qingfen liu CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China

Industrial pharmaceutical wastewater usually contains butyl acetate(BA)with a concentration of 1 wt%-7 wt%,and the traditional method for BA recovery is distillation with high energy *** method is developed to recover BA with low concentration for the high efficiency and low energy *** polar polyacrylate resins with macroporous structure of 233.1 nm and average particle size of about 526.5μm are successfully synthesized by suspension polymerization and used for the BA adsorption and *** maximum adsorption capacity reaches 171.1 mg g^(-1)with relative standard deviation(RSD)value of 0.2%,which is more than twice the results in the *** BA desorption rate is 97.0%at 100℃with RSD value of 0.4%,and the resins are beneficial to the reuse in the adsorption-desorption *** adsorption thermodynamics and kinetics are investigated,and the BA adsorption is a spontaneous and endothermic process with the increase of disorder *** process is mainly contributed by physical absorption and agree well with Freundlich model and pseudo-first-order adsorption kinetic *** adsorption method avoids boiling a large amount of wastewater and hopefully provides a novel alternative technology for the BA recovery.

关键词： Butyl acetate recovery Resin adsorption Desorption Thermodynamics Kinetics

Synergistic effect and heterointerface engineering of cobalt/carbon nanotubes enhancing electromagnetic wave absorbing properties of silicon carbide fibers

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Nano Research 2024年第9期17卷 8479-8486页

作者： Zixiang Zhao Zheyipei Ma Zizhao Ding Yanqiong liu Mingwei Zhang Chao Jiang Institute of Powder Metallurgy Research Central South UniversityChangsha 410083China

To improve the synergistic effect between dielectric and magnetic loss is a practical and effective way in optimizing electromagnetic wave absorbing *** composites of metal particles and carbon ligands derived from metal organic frameworks have gained wide *** this study,Co particles and multiwalled carbon nanotubes(CNT)were successfully synthesized covering the surface of silicon carbide(SiC)fibers,and the morphology,interfaces and electromagnetic wave absorption performance were *** sample SiC@Co/CNT,the minimum reflection loss value can reach-70.22 dB at 11.21 GHz with the thickness of 2.12 *** effective absorbing bandwidth can reach up to 6.03 GHz with the thickness of 1.71 mm,which covers the entire Ku *** brings more interfaces between Co particles and CNTs as well as SiC fibers and Co/C *** interfacial polarization has been hugely enhanced,and the microwave absorbing properties have been *** article reports on the impedance matching of magnetic and non-magnetic components and the heterointerface engineering,which can be effective strategy and inspiration to illustrate the relationship between components,structures and functions of electromagnetic wave absorbing materials.

关键词： metal organic frameworks Co nanocrystals carbon nanotubes Schottky heterointerfaces synergistic effect

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基于空化时空分布特征的调节阀空蚀风险预测

华中科技大学学报（自然科学版） 2024年第6期52卷 71-79页

作者：张雨佳刘秀梅李贝贝刘申中国矿业大学机电工程学院江苏徐州221116

针对煤液化工程中的关键设备高压差调节阀耐空蚀能力差、使用寿命短的问题,利用高速相机拍摄获取调节阀空化流场图像,提出空隙率λ表征气相体积分数、空隙率变化速率β表征空蚀风险指标,实现了调节阀空蚀破坏的准确预测.结果表明:空隙... 详细信息

针对煤液化工程中的关键设备高压差调节阀耐空蚀能力差、使用寿命短的问题,利用高速相机拍摄获取调节阀空化流场图像,提出空隙率λ表征气相体积分数、空隙率变化速率β表征空蚀风险指标,实现了调节阀空蚀破坏的准确预测.结果表明:空隙率数值与气相体积分数正相关;随着入口压力的增大,阀芯头部和喉部对应空隙率数值增大,空化得到充分发展向扩张段延伸并溃灭,调节阀内空化呈初生、发展、脱落和溃灭的周期性变化趋势.当空隙率变化速率β<0时,表示空泡处于溃灭状态,据此可以判断该处存在空蚀风险;随着入口压力的增加,附着型空泡溃灭位置较为固定在调节阀头部,是阀芯发生空蚀破坏的主要原因.游离型空化损伤区域随着入口压力增加逐渐向调节阀下游延伸,调节阀流道上方和下方空化损伤区域为非对称结构,下方的空化损伤区域整体超前于上方.

关键词：空化调节阀空隙率空蚀破坏风险预测

替代性生计提高生态补偿有效性的效果与机理——以草原生态补奖政策为例

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草业学报 2024年第6期33卷 29-46页

作者：苏柳方仇焕广刘会芳侯玲玲华南农业大学经济管理学院广东广州510642 中国人民大学农业与农村发展学院北京100872 兰州大学草地农业科技学院甘肃兰州730020 北京大学现代农学院北京100871

生态补偿有效性不足,资源约束下的生计受限是政策失效的重要原因。从替代性生计视角探讨生态补偿有效性提升,可为生态补偿和生计关系的不一致观点提供调和思路,也有助于促进生态补偿深化改革。本研究以草原生态补奖政策为例,利用甘肃和... 详细信息

生态补偿有效性不足,资源约束下的生计受限是政策失效的重要原因。从替代性生计视角探讨生态补偿有效性提升,可为生态补偿和生计关系的不一致观点提供调和思路,也有助于促进生态补偿深化改革。本研究以草原生态补奖政策为例,利用甘肃和青海两年追踪调查数据,基于牧户禁牧行为实验,采用区间数据模型和双变量probit模型,从非牧就业和就业培训视角,检验牧户过去6年的替代性生计特征和村级过去4年的替代性生计措施对牧户禁牧受偿意愿的影响,揭示替代性生计对草原生态补奖政策有效性的提升作用。结果发现:牧户替代性生计特征是降低其禁牧受偿意愿、在当前补偿标准下优化补奖政策效果的重要因素,但只有高收益、高稳定性的高技能非牧就业才能发挥有效作用;村级提供就业培训服务有利于降低牧户禁牧受偿意愿、在当前补偿标准下提升补奖政策有效性,但该作用需持续3~4年的累积才能显现。因此,生态补偿改革应充分重视受偿主体的替代性生计转型和发展问题。

关键词：草原生态补奖政策替代性生计非牧就业培训受偿意愿行为经济学

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收缩理论在系统控制中的发展及应用

控制与决策 2024年第3期39卷 719-727页

作者：刘艳红李孟琪李方圆郑州大学电气与信息工程学院郑州450001 郑州大学河南省机器人感知与控制工程研究中心郑州450001

收缩理论作为一种区别于Lyapunov理论的非线性系统分析方法,它主要基于微分几何和流体力学的知识发展而来,为系统控制提供了新颖视角和理论工具.首先,介绍收缩理论的一些基础知识,以及收缩系统的联合、部分收缩理论和控制收缩度量等重... 详细信息

收缩理论作为一种区别于Lyapunov理论的非线性系统分析方法,它主要基于微分几何和流体力学的知识发展而来,为系统控制提供了新颖视角和理论工具.首先,介绍收缩理论的一些基础知识,以及收缩系统的联合、部分收缩理论和控制收缩度量等重要结果;然后,综述收缩理论在分析系统稳定性、跟踪控制、协同控制、状态估计以及学习控制等领域的应用现状;最后,对收缩理论的未来发展趋势进行展望.

关键词：非线性系统收缩理论控制收缩度量跟踪控制协同控制状态估计学习控制

根灌外源褪黑素对干旱胁迫下紫花苜蓿生理特性的影响研究

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草地学报 2024年第1期32卷 198-206页

作者：张玲麻冬梅刘晓霞马巧利侯汶君李嘉文苏立娜杭嘉慧宁夏大学西北土地退化与生态系统恢复省部共建国家重点实验室培育基地/西北退化生态系统恢复与重建教育部重点实验室宁夏大学生态环境学院宁夏银川750021 宁夏大学林业与草业学院宁夏银川750021

为探究褪黑素对干旱胁迫下紫花苜蓿(Medicago sativa L.)生长的影响,本研究以‘中苜3号’紫花苜蓿为试验材料,设置正常供水和干旱2个水分梯度,采用盆栽试验根灌不同浓度褪黑素,分析不同条件下幼苗表型、生理生化指标的变化。结果表明:90... 详细信息

为探究褪黑素对干旱胁迫下紫花苜蓿(Medicago sativa L.)生长的影响,本研究以‘中苜3号’紫花苜蓿为试验材料,设置正常供水和干旱2个水分梯度,采用盆栽试验根灌不同浓度褪黑素,分析不同条件下幼苗表型、生理生化指标的变化。结果表明:90μmol·L^(-1)褪黑素处理能够显著提高紫花苜蓿幼苗株高、茎粗、相对含水量、相对叶绿素含量,此外,90μmol·L^(-1)褪黑素处理显著增加干旱胁迫下紫花苜蓿幼苗叶片抗氧化酶活性及酶合成相关基因表达水平,并降低脯氨酸、可溶性糖含量及丙二醛、相对电导率、过氧化氢含量。综上所述,褪黑素提高干旱胁迫下紫花苜蓿幼苗抗氧化酶生物合成基因表达水平,增强抗氧化酶活性,清除过量活性氧,缓解膜损伤,提高幼苗抗旱性。

关键词：紫花苜蓿干旱褪黑素渗透调节抗氧化酶

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Mechanical response of a tunnel subjected to strike-slip faulting processes,based on a multi-scale modeling method

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1281-1295页

作者： Guoguo liu Ping GENG Tianqiang WANG Xiangyu GUO Jiaxiang WANG Ti DING Key Laboratory of Transportation Tunnel Engineering Ministry of EducationChengdu 610031China College of Civil Engineering Huaqiao UniversityXiamen 361021China China Railway Design Corporation Tianjin 300308China

The stick-slip action of strike-slip faults poses a significant threat to the safety and stability of underground *** this study,the north-east area of the Longmenshan fault,Sichuan,provides the geological background;the rheological characteristics of the crustal lithosphere and the nonlinear interactions between plates are described by Burger’s viscoelastic constitutive model and the friction constitutive model,respectively.A large-scale global numerical model for plate squeezing analysis is established,and the seemingly periodic stick-slip action of faults at different crust depths is *** a second model at a smaller scale,a local finite element model(sub-model),the time history of displacement at a ground level location on the Longmenshan fault plane in a stick-slip action is considered as the displacement *** integration of these models,creating a multi-scale modeling method,is used to evaluate the crack propagation and mechanical response of a tunnel subjected to strike-slip *** determinations of the recurrence interval of stick-slip action and the cracking characteristics of the tunnel are in substantial agreement with the previous field investigation and experimental results,validating the multi-scale modeling *** can be concluded that,regardless of stratum stiffness,initial cracks first occur at the inverted arch of the tunnel in the footwall,on the squeezed side under strike-slip *** smaller the stratum stiffness is,the smaller the included angle between the crack expansion and longitudinal direction of the tunnel,and the more extensive the crack expansion *** the tunnel in a high stiffness stratum,both shear and bending failures occur on the lining under strike-slip faulting,while for that in the low stiffness stratum,only bending failure occurs on the lining.

关键词： stick-slip action plate squeezing analysis multi-scale modeling method lining cracking mechanical response

Multi-locomotion transition of tensegrity mobile robot under different terrains

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Science China(Technological Sciences) 2024年第2期67卷 536-557页

作者： YANG Qi liu XinYu WANG PanFeng SONG YiMin SUN Tao Key Laboratory of Mechanism Theory and Equipment Design(Tianjin University) Ministry of EducationTianjin UniversityTianjin 300350China

Knowing how to make a multi-locomotion robot achieve locomotion transition under different terrains is a challenging problem,especially for tensegrity robots with multi-locomotion *** this study,a motion planning method for the transition of a multi-locomotion tensegrity robot(hereafter TJUBot)under different terrains is *** robot can achieve four locomotion modes:earthworm-like,inchworm-like,tumbling,and sliding locomotion with only two *** models of the four locomotion modes under five typical terrains,including flat ground,confined space,obstacle,gap,and descending slope,are established using the energy ***,the kinematic characteristics(driving law and initial position)of the robot under these terrains are *** this basis,motion planning for the locomotion transition of TJUBot is conducted,which includes a perception strategy based on three laser sensors and a transition strategy under different *** driving laws of the two motors that can ensure the effective locomotion transition of TJUBot under different terrains are naturally ***,experiments are *** demonstrate that the robot can achieve effective locomotion transition when the motion planning method is used.

关键词： multi-locomotion robot tensegrity kinematic modeling locomotion transition