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Multi-layer quasi-zero-stiffness meta-structure for high-efficiency vibration isolation at low frequency

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1189-1208页

作者： Jiahao zhou jiaxi zhou Hongbin PAN Kai WANG Changqi CAI Guilin WEN College of Mechanical and Vehicle Engineering Hunan University State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body The Ministry of Science and Technology School of Mechanical Engineering Zhejiang Sci-Tech University School of Mechanical Engineering Yanshan University

An easily stackable multi-layer quasi-zero-stiffness(ML-QZS) meta-structure is proposed to achieve highly efficient vibration isolation performance at low ***, the distributed shape optimization method is used to design the unit cel, i.e., the single-layer QZS(SL-QZS) meta-structure. Second, the stiffness feature of the unit cell is investigated and verified through static experiments. Third, the unit cells are stacked one by one along the direction of vibration isolation, and thus the ML-QZS meta-structure is constructed. Fourth, the dynamic modeling of the ML-QZS vibration isolation metastructure is conducted, and the dynamic responses are obtained from the equations of motion, and verified by finite element(FE) simulations. Finally, a prototype of the ML-QZS vibration isolation meta-structure is fabricated by additive manufacturing, and the vibration isolation performance is evaluated experimentally. The results show that the vibration isolation performance substantially enhances when the number of unit cells increases. More importantly, the ML-QZS meta-structure can be easily extended in the direction of vibration isolation when the unit cells are properly stacked. Hence, the ML-FQZS vibration isolation meta-structure should be a fascinating solution for highly efficient vibration isolation performance at low frequency.

关键词： quasi-zero stiffness (QZS) meta-structure high efficiency low frequency vibration isolation O328 34C15 74P10

Modeling and analysis of gradient metamaterials for broad fusion bandgaps

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1155-1170页

作者： Changqi CAI Chenjie ZHU Fengyi ZHANG Jiaojiao SUN Kai WANG Bo YAN jiaxi zhou School of Mechanical Engineering Zhejiang Sci-Tech University School of Material and Environmental Engineering Hangzhou Dianzi University College of Mechanical and Vehicle Engineering Hunan University

A gradient metamaterial with varying-stiffness local resonators is proposed to open the multiple bandgaps and further form a broad fusion bandgap. First, three local resonators with linearly increasing stiffness are periodically attached to the spring-mass chain to construct the gradient metamaterial. The dispersion relation is then derived based on Bloch's theorem to reveal the fusion bandgap theoretically. The dynamic characteristic of the finite spring-mass chain is investigated to validate the fusion of multiple bandgaps. Finally, the effects of the design parameters on multiple bandgaps are discussed. The results show that the metamaterial with a non-uniform stiffness gradient pattern is capable of opening a broad fusion bandgap and effectively attenuating the longitudinal waves within a broad frequency region.

关键词： local resonance mechanism elastic metamaterial stiffness gradient bandgap fusion broadband wave attenuation O321 74H45 74J05

2000-2020年长江中下游地区耕地生产力对气候变化的动态响应

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应用与环境生物学报 2024年第2期30卷 238-246页

作者：周佳茜蒋艳萍乡市气象局萍乡337000 中南林业科技大学生命科学与技术学院长沙410004 中南林业科技大学南方林业生态应用技术国家工程实验室长沙410004

长江中下游地区是我国重要的粮食产区,探究其耕地生产力对气候变化的动态响应,对于应对日益增长的人类需求和不断加剧的气候变化、保障粮食安全具有重要意义.以植被净初级生产力(NPP)作为耕地生产力的评价指标,从区域尺度和格网尺度上,... 详细信息

长江中下游地区是我国重要的粮食产区,探究其耕地生产力对气候变化的动态响应,对于应对日益增长的人类需求和不断加剧的气候变化、保障粮食安全具有重要意义.以植被净初级生产力(NPP)作为耕地生产力的评价指标,从区域尺度和格网尺度上,分析2000-2020年长江中下游地区耕地NPP的时空变化特征,并量化NPP与气候因子(气温和降水)的相关性.结果显示:(1)从区域尺度上看,研究期间耕地NPP以3.42 g m^(-2)a^(-1)的速率呈波动上升趋势,并且在2013年出现了突变点.长江以南地区的耕地NPP要高于长江以北地区,离长江越远的耕地NPP越高;从格网尺度上看,研究期间大部分耕地的NPP呈上升趋势,但是未来可能呈增长放缓或退化趋势;(2)研究区耕地NPP与年降水量、年均气温呈正相关关系,降水的影响要强于温度;降水量对耕地NPP的影响具有显著的南北差异,降水与NPP呈正相关的耕地大部分位于长江以北地区,呈负相关的耕地大部分位于长江以南地区.气温与耕地NPP的相关关系在沿长江的梯度带上具有显著的空间差异,离长江越近,NPP与气温呈负相关的耕地越多.本研究表明气候变化的湿暖化促进了耕地植被的生长,耕地NPP对气候变化的响应具有显著的空间异质性.(图7表1参45)

关键词：耕地生产力气候变化植被净初级生产力空间异质性长江中下游地区

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Identification and characterization of human hematopoietic mesoderm

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Science China(Life Sciences) 2024年第2期67卷 320-331页

作者： Yuqi Wen Jingjing Zhao Runqing Zhang Fan Liu Xiaoyuan Chen Dan Wu Mengge Wang Cuicui Liu Pei Su Panpan Meng Yiyue Zhang Xin Gao Lu Wang Hongtao Wang jiaxi zhou State Key Laboratory of Experimental Hematology National Clinical Research Center for Blood DiseasesHaihe Laboratory of Cell EcosystemInstitute of Hematology&Blood Diseases HospitalChinese Academy of Medical Sciences&Peking Union Medical CollegeTianjin 300020China Tianjin Institutes of Health Science Tianjin 301600China CAMS Center for Stem Cell Medicine PUMC Department of Stem Cell and Regenerative MedicineTianjin 300020China Division of Cell Developmental and Integrative BiologySchool of MedicineSouth China University of TechnologyGuangzhou 510006China

The embryonic mesoderm comprises heterogeneous cell subpopulations with distinct lineage *** is unclear whether a bias for the human hematopoietic lineage emerges at this early developmental *** this study,we integrated single-cell transcriptomic analyses of human mesoderm cells from embryonic stem cells and embryos,enabling us to identify and define the molecular features of human hematopoietic mesoderm(HM)cells biased towards hematopoietic *** discovered that BMP4 plays an essential role in HM specification and can serve as a marker for HM ***,BMP4 acts as a downstream target of HDAC1,which modulates the expression of BMP4 by deacetylating its *** of HDAC significantly enhances HM specification and promotes subsequent hematopoietic cell *** conclusion,our study identifies human HM cells and describes new mechanisms for human hematopoietic development.

关键词： hematopoietic mesoderm human pluripotent stem cells human embryos BMP4 HDAC1

何处为“家”?:《哈克贝利·费恩历险记》的地方意义

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外国语言文学 2024年第2期41卷 66-75,134,135页

作者：周家西刘立辉西南大学

马克·吐温的《哈克贝利·费恩历险记》呈现了一个流动的地理空间,小说中哈克和吉姆在理想空间与现实空间中不断移动。密西西比河不仅作为美国的“母亲河”,在小说里更充当了连接现实与理想的时空隧道,以“家”“小镇”“杰克逊岛”“... 详细信息

马克·吐温的《哈克贝利·费恩历险记》呈现了一个流动的地理空间,小说中哈克和吉姆在理想空间与现实空间中不断移动。密西西比河不仅作为美国的“母亲河”,在小说里更充当了连接现实与理想的时空隧道,以“家”“小镇”“杰克逊岛”“木筏”为代表的典型空间通过密西西比河完美地串联起来。根据人文地理学的解释,个体经历可以将无意义的空间转变成赋有意义的“地方”。时空的流动之中,哈克和吉姆赋予这些空间以“家”的内涵,在寻找自由与平等时,他们的空间流动表征了美国这个年轻的国度不断走向成熟的经历。

关键词：家地方河流《哈克贝利·费恩历险记》

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滇西首例火成碳酸岩的发现与厘定

岩石学报 2024年第9期40卷 2638-2652页

作者：高雅俊宋文磊周家喜雷碧东杨金昆许丹妮罗开云南大学地球科学学院云南省高校关键矿产成矿学重点实验室昆明650500 云南大学自然资源部三江成矿作用及资源勘查利用重点实验室昆明650500 西北大学地质学系大陆动力学国家重点实验室西安710069 云南黄金矿业集团股份有限公司勘查分公司昆明650299

火成碳酸岩(又称碳酸岩)是由地幔派生的富碳酸盐矿物且贫硅的火成岩石,地表出露较少。碳酸岩是研究地幔性质及其演化过程的岩石“探针”,并且蕴藏着丰富的稀土和铌等关键金属矿产资源。因此,对它的研究具有重要的科学和经济价值。本次... 详细信息

火成碳酸岩(又称碳酸岩)是由地幔派生的富碳酸盐矿物且贫硅的火成岩石,地表出露较少。碳酸岩是研究地幔性质及其演化过程的岩石“探针”,并且蕴藏着丰富的稀土和铌等关键金属矿产资源。因此,对它的研究具有重要的科学和经济价值。本次工作首次在云南保山龙陵地区发现火成碳酸岩岩体,规模较大,岩体出露面积约为60000m 2。出露于保山地块与腾冲地块之间的龙陵-潞西褶皱带内。新发现的碳酸岩主要由方解石和白云石等矿物组成,其次还含有大量的磷灰石、磁铁矿、黑云母、辉石、独居石和斜锆石等副矿物。结合岩相学、矿物学和全岩地球化学组成,可将新发现的碳酸岩划分为钙质、镁质和含铁钙质三类。不同岩性的CaO(29.57%~51.66%)、Fe_(2)O^(T)_(3)(0.72%~21.15%)和MgO(1.76%~16.90%)含量变化大。微量元素特征显示,碳酸岩总体富集Sr(3431×10^(-6)~9753×10^(-6))、Ba(197×10^(-6)~2428×10^(-6))、Pb(14.4×10^(-6)~425×10^(-6))和∑REE(841×10^(-6)~2341×10^(-6))等大离子亲石元素,相对亏损Nb(1.09×10^(-6)~12.48×10^(-6))、Ta(0.12×10^(-6)~4.74×10^(-6))和Hf(0.07×10^(-6)~7.85×10^(-6))等高场强元素。稀土配分模式为右倾型,(La/Yb)N比值介于58~104之间,富集LREE,具有弱铕负异常(δEu=0.68~0.74)。碳酸岩中主要造岩矿物方解石、白云石和磷灰石也表现出与全岩相似的元素地球化学特征。碳酸盐矿物的δ^(13)C V-PDB值(-7.45‰~-3.54‰)大多落入“初始火成碳酸岩”范围,但δ^(18)O V-SMOW值(10.79‰~20.06‰)偏高,很可能源于岩浆期后热液蚀变。上述全岩、矿物化学和C-O同位素特征与全球大多数碳酸岩基本一致,证实坡头岩体为典型的火成碳酸岩。钙质碳酸岩中斜锆石的LA-ICPMS测年结果显示,其U-Pb等时线谐和年龄为160.7±2.0Ma(MSWD=1.8),^(206)Pb/^(238)U加权平均年龄为159.7±1.8Ma(MSWD=2.4),表明其形成于中侏罗世,为三叠纪碰撞造山作用后的岩浆活动产物。坡头碳酸岩的发现与厘定将有助于揭示所在区域地幔特征,其关键金属成矿潜力也值得进一步的探究。

关键词：坡头碳酸岩全岩地球化学 C-O同位素斜锆石U-Pb年龄云南保山

Fractional nonlinear energy sinks

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Applied Mathematics and Mechanics(English Edition) 2023年第5期44卷 711-726页

作者： Shengtao ZHANG jiaxi zhou Hu DING Kai WANG Daolin XU College of Mechanical and Vehicle Engineering Hunan UniversityChangsha 410082China Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China

The cubic or third-power(TP)nonlinear energy sink(NES)has been proven to be an effective method for vibration suppression,owing to the occurrence of targeted energy transfer(TET).However,TET is unable to be triggered by the low initial energy input,and thus the TP NES would get failed under low-amplitude *** resolve this issue,a new type of NES with fractional nonlinearity,e.g.,one-third-power(OTP)nonlinearity,is *** dynamic behaviors of a linear oscillator(LO)with an OTP NES are investigated numerically,and then both the TET feature and the vibration attenuation performance are ***,an analogy circuit is established,and the circuit simulations are carried out to verify the design concept of the OTP *** is found that the threshold for TET of the OTP NES is two orders of magnitude smaller than that of the TP *** parametric analysis shows that a heavier mass or a lower stiffness coefficient of the NES is beneficial to the occurrence of TET in the OTP NES ***,significant energy transfer is usually accompanied with efficient energy ***,the OTP NES can realize TET under low initial input energy,which should be a promising approach for micro-vibration suppression.

关键词： fractional nonlinearity nonlinear energy sink(NES) targeted energy transfer(TET) micro-vibration control

贵州半边街锗锌矿床锗的富集特征及其地质意义

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岩石学报 2024年第1期40卷 43-59页

作者：程涌周家喜孙国涛黄智龙云南大学地球科学学院云南省高校关键矿产成矿学重点实验室昆明650500 昆明冶金高等专科学校冶金与矿业学院昆明650033 云南省三江成矿作用及资源勘查利用重点实验室昆明650500 自然资源部三江成矿作用及资源勘查利用重点实验室昆明650500 贵州大学资源与环境工程学院贵阳550025 中国科学院地球化学研究所矿床地球化学国家重点实验室贵阳550081

锗(Ge)属于战略性关键矿产资源,是众多高新技术领域的重要原材料。Ge主要以共/伴生形式产出于Zn、Pb和Cu等热液贱金属矿床和煤矿床中,目前全球Ge资源主要来源于铅锌矿的副产品。近期取得较大找矿突破的半边街锌矿床(7.70Mt矿石,Zn平均品... 详细信息

锗(Ge)属于战略性关键矿产资源,是众多高新技术领域的重要原材料。Ge主要以共/伴生形式产出于Zn、Pb和Cu等热液贱金属矿床和煤矿床中,目前全球Ge资源主要来源于铅锌矿的副产品。近期取得较大找矿突破的半边街锌矿床(7.70Mt矿石,Zn平均品位5.1%)伴生有超大型规模的金属Ge(>900t@110×10^(-6)),然而Ge超常富集的机制不清。本次研究利用LA-ICPMS对闪锌矿进行了微区原位微量元素组成和Mapping分析,以揭示Ge等元素的富集特征、赋存状态和替代方式,探讨Ge的富集机制。分析结果表明,半边街矿床闪锌矿中高含量(平均值>100×10^(-6))微量元素有Fe、Pb、Ge和Cd等,较高含量(平均值100×10^(-6)~10×10^(-6))的有Mn、Ga、Sn和Tl,以及较低含量(平均值<10×10^(-6))的有Ag、Cu、In和Sb。相比于各类型铅锌矿床,半边街闪锌矿Ge超常富集(274×10^(-6)~1938×10^(-6),平均为1055×10^(-6),达到1000倍富集)。该矿床中Ge以类质同象或纳米颗粒形式赋存于闪锌矿中。微量元素摩尔量相关性图揭示Ge替代Zn的方式以Ge^(4+)+Pb^(2+)3Zn^(2+)为主,其次为nGe^(4+)+Mn 2+(2n+1)Zn^(2+)和nGe^(4+)+2Tl^(3+)(2n+3)Zn^(2+)。综合分析认为,半边街矿床Ge可能来源于相对富Ge的前寒纪基底;富有机质的盆地流体在Ge的搬运中发挥重要作用;Ge、Cd等稀散元素的共生分异制约了Ge的最终超常富集。因此,半边街矿床中Ge的超常富集是“源、运、聚”复杂过程多要素耦合作用的结果。

关键词：微量元素闪锌矿锗(Ge) 替代机制半边街锗锌矿床

A Paleozoic mercury mineralisation event in South China:In situ U-Pb dating and chemical compositions of calcite from the Jianyan Hg deposit

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Science China Earth Sciences 2023年第8期66卷 1877-1891页

作者： Kai LUO jiaxi zhou Alexandre CUGERONE Meifu zhou Yuexing FENG Zhongguo JIN Jianxin ZHAO Key Laboratory of Critical Minerals Metallogeny in Universities of Yunnan Province School of Earth SciencesYunnan UniversityKunming 650500China School of Earth and Environmental Sciences The University of QueenslandBrisbane QLD 4072Australia State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Department of Earth Sciences University of GenevaGeneva 1205Switzerland Southern Marine Science and Engineering Guangdong Laboratory Zhuhai 519000China Non-Ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou Guiyang 550005China

The ages of hydrothermal Hg deposits are difficult to constrain because of the lack of suitable minerals for *** South China low-temperature metallogenic domain hosts numerous Hg deposits,including the Jianyan Hg deposit that is composed mainly of cinnabar and *** are two stages of calcite in the deposit:syn-ore calcite(Cal-Ⅰ)and post-ore/barren calcite(Cal-Ⅱ).Cal-Ⅰis mainly euhedral-subhedral and fine-grained,has homogeneous grey luminescence,and is associated with ***-anhedral Cal-Ⅱcrosscuts Cal-Ⅰand is relatively *** syn-ore Cal-Ⅰhas high U contents(0.1–1.3 ppm)and U/Pb ratios(up to 4.2),and is thus suitable for U-Pb *** a laser ablation-inductively coupled plasma-mass spectrometer equipped with ion counters,we obtained a U-Pb age of 426.3±5.7 Ma(MSWD=1.5)for *** age is interpreted to represent the timing of Hg mineralisation at Jianyan and is similar to ages of 440–400 Ma reported for many carbonate-hosted Pb-Zn and Ba-F deposits in South *** on the present results in combination with existing geochemical and geochronological data,we infer that these deposits belong to a Paleozoic Hg-Pb-Zn-Ba-F mineralisation system that was controlled by Caledonian tectonism.

关键词： In situ calcite U-Pb dating Paleozoic Hg mineralisation Caledonian tectonism Jianyan Hg deposit South China