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Compressive property and energy absorption characteristic of interconnected porous Mg-Zn-Y alloys with adjusting Y addition

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Journal of Magnesium and Alloys 2024年第1期12卷 171-185页

作者： J.A.Liu S.J.Liu b.wang w.b.Sun X.J.Liu Z.w.Han College of Materials Science and Engineering Key Laboratory of Automobile Materials(Ministry of Education)Jilin UniversityChangchun 130022PR China Key Laboratory of bionic Engineering(Ministry of Education) College of Biological and Agricultural EngineeringJilin UniversityChangchun130022PR China weihai Institute for bionics-Jilin University Weihai 264205PR China

In this study,interconnected porous Mg-2Zn-xY alloys with different phase compositions were prepared by various Y additions(x=0.4,3,and 6 wt.%)to adjust the compressive properties and energy absorption *** characterization methods were then applied to identify the microstructure of the porous Mg-Zn-Y and describe the details of the second *** tests were performed at room temperature(RT),200℃,and 300℃to study the impact of the Y addition and testing temperature on the compressive properties of the porous *** experimental results showed that a high Y content promotes a microstructure refinement and increases the volume fraction of the second *** the Y content increases,different Mg-Zn-Y ternary phases appear:I-phase(Mg_(3)Zn_(6)Y),w-phase(Mg_(3)Zn_(3)Y_(2)),and LPSO phase(Mg_(12)ZnY).when the Y content ranges between 0.4%and 6%,the compressive strength increases from 6.30MPa to 9.23 MPa,and the energy absorption capacity increases from 7.33 MJ/m^(3)to 10.97 MJ/m^(3)at RT,which is mainly attributed to the phase composition and volume fraction of the second ***,the average energy absorption efficiency is independent of the Y *** addition,the compressive deformation behaviors of the porous Mg-Zn-Y are altered by the testing *** compressive strength and energy absorption capacity of the porous Mg-Zn-Y decrease due to the softening effect of the high temperature on the *** deformation behaviors at different temperatures are finally observed to reflect the failure mechanisms of the struts.

关键词： Porous magnesium Rare earth elements Microstructure Compressive behavior Energy absorption characteristic

Probing the bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

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Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： S R wu b Q wang Z w Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric bardeen-Kiselev black hole(bH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the bardeen-Kiselev bH with the cosmological constant due to electromagnetic and gravitational *** varying the bH parameters,we discuss the behavior of both real and imaginary parts of the bH quasinormal frequencies and compare these frequencies with the Reissner-Nordström-de Sitter bH surrounded by quintessence(RN-dSQ).Interestingly,it is shown that the responses of the bardeen-Kiselev bH with the cosmological constant and the RN-dSQ under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the bardeen-Kiselev bH with the cosmological constant and the RN-dSQ are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the bardeen-Kiselev bH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the bardeen-Kiselev bH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors bardeen-Kiselev black hole with cosmological constant

全光纤结构拉曼振荡器实现近1.8 kw激光输出

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红外与激光工程 2024年第5期53卷 268-270页

作者：范晨晨付敏郝修路黄善旻李阳陈子伦冷进勇姚天甫周朴国防科技大学前沿交叉学科学院湖南长沙410073 国防科技大学南湖之光实验室湖南长沙410073 国防科技大学高能激光技术湖南省重点实验室湖南长沙410073

拉曼光纤激光器在实现高功率特殊波长激光方面具有独特优势,受到了广泛关注和研究。近年来,随着渐变折射率多模光纤在拉曼激光器中的运用,不仅提高了可注入的泵浦功率,还通过光束净化特性实现了激光亮度增强。

关键词：光纤激光拉曼振荡器受激拉曼散射渐变折射率光纤

变周期亚波长介质光栅多层膜的双重Fano共振特性

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光谱学与光谱分析 2024年第3期44卷 681-687页

作者：肖春艳杨晨周鑫德河南理工大学资源环境学院河南焦作454003 燕山大学电气工程学院河北省测试计量技术及仪器重点实验室河北秦皇岛066004

现在众多传感结构模型只能对单变量待测样本折射率进行传感检测,为实现不同待测样本的高通量检测并降低环境因素的干扰,提出了一种基于波长调制的变周期亚波长介质光栅多层膜复合结构。以双周期为例进行分析,变周期光栅层由两个具有不... 详细信息

现在众多传感结构模型只能对单变量待测样本折射率进行传感检测,为实现不同待测样本的高通量检测并降低环境因素的干扰,提出了一种基于波长调制的变周期亚波长介质光栅多层膜复合结构。以双周期为例进行分析,变周期光栅层由两个具有不同光栅周期的介质光栅A和b组成,通过有限元法对传输特性进行分析,TE偏振入射光以垂直于光栅层表面的方式入射至介质光栅表面,当在介质光栅区域A和b内分别满足相位匹配条件时,变周期亚波长介质光栅会形成GMR,提供两个具有单一窄带的双离散态共振缺陷峰;由于类F-P腔中含有周期性光子晶体,光波传播到光子晶体会产生光子禁带,提供一个较宽频带的连续态。在满足相位匹配条件时,变周期亚波长波导结构中形成的双离散态共振缺陷峰与周期性光子晶体多层介质薄膜构成的类F-P腔中形成的连续态发生耦合,实现双重Fano共振。然后通过探究波导层厚度dw和光子晶体周期数N对传感特性的影响,选择dw=97 nm和N=3,使其达到FOM值最大。最终因变周期介质光栅层是由两种具有不同介质折射率的材料构成,在介质光栅区域A和b的光栅凹槽部分可设置两个传感检测单元,建立基于波长调制的双重Fano共振全电介质传感模型,设置不同的传感检测区域,发现双重Fano光谱曲线在不同传感检测区域内都能随着ns1和ns2变化,间接实现了对待测样本折射率的动态检测,因而可在同一传感结构模型中实现对不同待测样本折射率区间的多变量检测。结果表明,在传感检测单元A内,FR1和FR2的FOM值分别为631.53和463.7 RIU^(-1);在传感检测单元b内,FOM值分别为480.67和834.04 RIU^(-1)。所设计的传感结构模型通过结构参数优化,实现了传感结构的高反射率、高FOM值和较宽的检测范围,对双重Fano共振提供了理论参考,对待测样本折射率的多变量检测具有一定的研究价值。

关键词：传感器双重Fano共振变周期亚波长光栅导模共振周期性光子晶体多层膜

高导热氮化硼/天然橡胶纳米复合材料的制备与性能

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化工进展 2024年

作者：王林艳周平德张一铎刘钰溪郝明正梁玉蓉太原工业学院材料工程系

采用葡萄糖辅助球磨六方氮化硼（bN），通过b—O化学键将葡萄糖成功接枝在bN分子上，制备得到bN-OH纳米片。将不同含量的bN-OH纳米片与天然胶乳（NR）粒子通过胶乳共沉淀制备得到了均匀的隔离网络结构，在NR胶乳粒子周围蛋白质的辅助下b... 详细信息

采用葡萄糖辅助球磨六方氮化硼（bN），通过b—O化学键将葡萄糖成功接枝在bN分子上，制备得到bN-OH纳米片。将不同含量的bN-OH纳米片与天然胶乳（NR）粒子通过胶乳共沉淀制备得到了均匀的隔离网络结构，在NR胶乳粒子周围蛋白质的辅助下bN-OH纳米片与NR分子链通过氢键等形成了物理交联。考察了bN-OH纳米片的含量对bN-OH/NR纳米复合材料的交联密度、机械性能、导热性能和气体阻隔性能等的影响。在一定范围内，随bN-OH纳米片填充量的增加，bN-OH/NR纳米复合材料的拉伸强度、定伸应力增加，储能模量上升，损耗因子下降，表明了bN-OH纳米片良好的补强作用和强两相界面结合作用力。bN-OH纳米片良好的分散，形成的隔离网络结构，以及蛋白质辅助物理交联所形成的强有力的界面相互作用，阻隔了气体分子的扩散，同时热量沿搭接在一起的bN-OH纳米片释放出去，致使bN-OH/NR复合材料良好的导热性能和气体阻隔性能。20% bN-OH/NR纳米复合材料的导热系数为0.319 w/(m·K)，为导热材料，较纯NR的导热系数提升了94%。而不同含量的bN-OH/NR纳米复合材料的体积电阻率仍远高于绝缘临界电阻率的标准，即本文制备的绝缘、高机械性能、高导热和良好密封性能的橡胶复合材料有望应用于电子元器件、电池、汽车等领域的热界面材料。

关键词：复合材料纳米结构导热性能气体阻隔性能氮化硼天然橡胶

The impact of the Rural Minimum Living Standard Guarantee(Rural Dibao)Program on child nutrition outcomes

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Journal of Integrative Agriculture 2024年第2期23卷 444-456页

作者： Dian Chen Xiangming Fang Yu Chen Xiaodong Zheng Zhuo Chen Rodney b.w.Smith Academy of Global Food Economics and Policy China Agricultural UniversityBeijing 100083China School of Public Health Georgia State UniversityAtlanta 30303USA School of Economics Zhejiang Gongshang UniversityHangzhou 310018China College of Public Health University of GeorgiaAthens 30602USA Department of Applied Economics University of MinnesotaSaint Paul 55108USA

The Rural Minimum Living Standard Guarantee(Rural Dibao)is an important unconditional cash transfer program to alleviate poverty in rural *** the importance of children’s nutrition in breaking poverty cycles,little is known about the impact of Rural Dibao on child nutrition *** China Family Panel Studies(CFPS),this paper examines the effects of Rural Dibao on child nutrition outcomes and investigates potential pathways and heterogeneous *** exploit propensity score matching and difference-in-differences techniques to evaluate the effects of the Rural Dibao program on child nutrition *** results suggest that Rural Dibao significantly impacts the nutrition outcomes of children up to 15 years of ***,our results suggest that Rural Dibao improves child height-to-age z-scores by 1.05 standard deviations and lowers the probability of stunting by 11.9 percentage *** analyses suggest that increased protein intake is the main pathway through which Rural Dibao participation contributes to better nutrition *** also find that the effect of the program is more pronounced among girls,children who are non-left-behind or live with highly educated mothers,and those from low-income families and poor *** findings suggest that Rural Dibao participation helps improve child nutrition outcomes through improving diet quality.

关键词： Rural Minimum Living Standard Guarantee nutrition height-to-age z-scores stunting rural China

Inflow and outflow permeability tests in a very soft clay under low stresses

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3270-3283页

作者： J.w.S.Vargas F.A.b.Danziger F.R.Lopes T.Lunne Federal University of Rio de Janeiro Rio de JaneiroBrazil Norwegian Geotechnical Institute OsloNorway

In situ inflow and outflow permeability tests with the bAT probe at SarapuíII soft clay test site are presented.A description of the bAT permeability test is provided,discussing its advantages and shortcomings,especially in the case of very soft clays under low *** pressures were monitored during probe installation and were found to be slightly lower than piezocone u2 pore pressures,consistent with the position of the *** role of filter tip saturation was investigated after the usual saturation procedure provided an unsatisfactory pore pressure response during probe *** show that the vacuum saturation procedure provides adequate response during installation and increases the reliability of the coefficient of permeability determination in early *** inflow and outflow tests yielded similar results,indicating that careful execution of the test can lead to good test repeatability regardless of the loading *** sequences of alternated inflow and outflow tests have yielded similar results,indicating that soil reconsolidation and filter clogging were negligible in the tests *** are presented concerning the relationship between index parameters and the in situ coefficient of permeability for SarapuíII clay,which plot outside the range of existing databases.

关键词： Permeability test Soft clay bAT probe Inflow and outflow tests

Rescattering of stimulated Raman side scattering in nonuniform plasmas

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Matter and Radiation at Extremes 2024年第5期9卷 68-76页

作者： S.Tan Q.wang Y.Chen w.b.Yao C.Z.Xiao J.F.Myatt School of Physics and Electronics Hunan UniversityChangsha 410082China Institute of Applied Physics and Computational Mathematics Beijing 100094China School of Electrical and Information Engineering Anhui University of Science and TechnologyHuainanAnhui 232001China Department of Electrical and Computer Engineering University of Alberta9211116 St.NWEdmontonAlberta T6G 1H9Canada

Rescattering of stimulated Raman side scattering(SRSS)is observed for the first time via two-dimensional(2D)particle-in-cell(PIC)*** construct a theoretical model for the rescattering process,which can predict the region of occurrence of mth-order SRSS and estimate its *** rescattering process is identified by the 2D PIC simulations under typical conditions of a direct-drive inertial confinement fusion *** electrons produced by second-order SRSS propagate nearly perpendicular to the density gradient and gain nearly the same energy as in first-order SRSS,but there is no cascade acceleration to produce superhot *** studies for a wide range of ignition conditions show that SRSS and associated rescatterings are robust and important processes in inertial confinement fusion.

关键词： nonuniform acceleration scattering