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Damage effect and progressive failure mechanism of sandstone considering different flaw angles under dynamic loading

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Rock Mechanics Bulletin

Rock Mechanics Bulletin 2024年第1期3卷 81-96页

作者： Dongliang Ji Hui Cheng Hongbao Zhao state key laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuangChina key laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei Shijiazhuang Tiedao UniversityShijiazhuangChina School of Energy and Mining Engineering China University of Mining and Technology(Beijing)BeijingChina

In many engineering applications,it is essential to have information about rocks that inherently contain preexisting flaws under dynamic loading *** impact tests are conducted on samples with varying flaw angles using the split Hopkinson pressure bar(SHPB)test system and the Digital Image Correlation system(DIC).The characteristics of the samples after dynamic loading,including dynamic strength,energy dissipation,and fractal fracture,are compared and *** the flaw angle increases,the peak stress and strain exhibit a typical V-shaped pattern,reaching the minimum value at 30,and the initial initiation position shifts from the flaw tips to the middle of the *** modes can be divided into three modes depending on the flaw *** progressive failure process,taking into account the heterogeneity of the rock,is demonstrated by developing an elastic damage constitutive model that uses dynamic compression and tensile tests to parameterize *** the flaw angle increases,the initial damage zone also moves from the flaw tips to the middle of the *** around the hole with redistributed stress are observed,and the failure mechanisms can be explained with the aid of strain energy density(SED).Using fracture mechanics,the analytical solution of stress around the flaw is provided,and the variation of crack initiation angle,stress distribution,and energy dissipation under different flaw angles is theoretically explained,which is in good agreement with the experimental and simulated results.

关键词： Dynamic loading Damage evolution Constitutive model Flaw angle Energy dissipation

Correlation between the charge radii difference in mirror partner nuclei and thesymmetry energy slope

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Chinese Physics C 2024年第8期48卷 177-184页

作者： Xiao-Rong Ma Shuai Sun Rong An Li-Gang Cao School of Physics Ningxia UniversityYinchuan 750021China key laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China key laboratory of Beam Technology of Ministry of Education Institute of Radiation TechnologyBeijing Academy of Science and TechnologyBeijing 100875China

A correlation between the charge radii difference of mirror partner nucleiΔR_(ch) and the slope parameter L of symmetry energy has been built to ascertain the equation of state of isospin asymmetric nuclear *** this work,the influences of pairing correlations and isoscalar compression modulus on theΔRch are systematically investigated based on the Skyrme energy density functional *** calculated results suggest that the linear correlation betweenΔR_(ch) and L is decreased by the surface pairing *** slope parameter deduced from the difference of charge radii of mirror-pair nuclei ^(32)Ar-^(32)Si,^(36)Ca-^(36)S,^(38)Ca-^(38)Ar,and ^(54)Ni-^(54)Fe falls into the range of L=42.57−50.64 MeV,that is,the rather soft equation of state of asymmetric nuclear ***,the range of the slope parameter can also be influenced by the effective forces classified by various isoscalar incompressibility coefficients.

关键词： symmetry energy charge radius mirror-pair nuclei slope parameter

Dietary nutrition, intestinal microbiota dysbiosis and post-weaning diarrhea in piglets

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Animal Nutrition 2024年第2期17卷 188-207页

作者： Xuebing Han Xiangdong Hu Wei Jin Gang Liu Department of Urology Shengjing Hospital of China Medical University College of Bioscience and Biotechnology Hunan Agricultural University Hunan Provincial Engineering Research Center of Applied Microbial Resources Development for Livestock and Poultry state key laboratory of Subtropical Silviculture Zhejiang A&F University

Weaning is a critical transitional point in the life cycle of piglets. Early weaning can lead to post-weaning syndrome, destroy the intestinal barrier function and microbiota homeostasis, cause diarrhea and threaten the health of piglets. The nutritional components of milk and solid foods consumed by newborn animals can affect the diversity and structure of their intestinal microbiota, and regulate post-weaning diarrhea in piglets. Therefore, this paper reviews the effects and mechanisms of different nutrients,including protein, dietary fiber, dietary fatty acids and dietary electrolyte balance, on diarrhea and health of piglets by regulating intestinal function. Protein is an essential nutrient for the growth of piglets;however, excessive intake will cause many harmful effects, such as allergic reactions, intestinal barrier dysfunction and pathogenic growth, eventually aggravating piglet diarrhea. Dietary fiber is a nutrient that alleviates post-weaning diarrhea in piglets, which is related to its promotion of intestinal epithelial integrity, microbial homeostasis and the production of short-chain fatty acids. In addition, dietary fatty acids and dietary electrolyte balance can also facilitate the growth, function and health of piglets by regulating intestinal epithelial function, immune system and microbiota. Thus, a targeted control of dietary components to promote the establishment of a healthy bacterial community is a significant method for preventing nutritional diarrhea in weaned piglets.

关键词： Diarrhea Intestinal barrier Dietary protein Dietary fiber Dietary fatty acid Dietary electrolyte balance

植物响应逆境胁迫过程中的染色质3D结构重塑

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Science Bulletin 2024年第7期69卷 847-849页

作者：张霖霖刘建祥 state key laboratory of Plant Environmental Resilience College of Life SciencesZhejiang UniversityHangzhou 310027China

Being sessile,plants evolve different acclimation strategies at both the transcriptional and post-translational levels to cope with adverse environmental conditions[1].Several recent studies[2–9]have shown that gene expression at transcriptional level under abiotic stress conditions is associated with highly dynamic threedimensional(3D)chromatin reorganization.

关键词： 3D结构 evolve translational

A new TiO_(2) nanorods/MoTe_(2) quantum dots/Al_(2)O_(3) composite photocatalyst for efficient photoelectrochemical water splitting under simulated sunlight

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Frontiers of Materials Science 2024年第2期18卷 61-74页

作者： Jie Meng Hongmei Liu Sainan Zhang Baogui Ye Min Feng Daoai Wang School of Chemistry and Chemical Engineering Lanzhou Jiaotong UniversityLanzhou 730000China state key laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Qingdao Centerof Resource Chemistry and New Materials Qingdao 266100China Shandong laboratory of Advanced Materials and Green Manufacturing at Yantai Yantai 265503China

The solar-to-hydrogen conversion using the photoelectrochemical(PEC)method is a practical approach to producing clean ***,it relies on the availability of photocatalyst *** this work,a novel photocatalyst comprising molybdenum telluride quantum dots(MoTe_(2) QDs)-modified titanium dioxide nanorods(TiO_(2) NRs)was prepared for the enhancement of the PEC water splitting performance after combination with a Al_(2)O_(3) layer using the atomic layer deposition(ALD)***_(2) QDs were initially prepared,and then they were loaded onto TiO_(2) NRs using a warm water bath-based heating *** a layer of Al_(2)O_(3) was deposited onto resulted TiO_(2) NRs/MoTe_(2) QDs,the composite TiO_(2) NRs/MoTe_(2) QDs/Al_(2)O_(3) was finally *** simulated sunlight(100 mW·cm^(-2)),such a composite exhibited a maximum photocurrent density of 2.25 mA·cm^(-2) at 1.23 V(versus RHE)and an incident photon-to-electron conversion efficiency of 69.88%at 380 nm,which are 4.33 and 6.66 times those of pure TiO_(2) NRs,***,the composite photocatalyst fabricated in this work may have promising application in the field of PEC water splitting,solarcells andotherphotocatalyticdevices.

关键词： MoTe_(2)quantum dot TiO_(2)nanorod Al_(2)O_(3) atomic layer deposition photoelectrochemistry

Ba^(2+)/Ca^(2+)co-crosslinked alginate hydrogel filtration membrane with high strength,high flux and stability for dye/salt separation

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Chinese Chemical Letters 2024年第5期35卷 320-324页

作者： Ningning Gao Yue Zhang Zhenhao Yang Lijing Xu Kongyin Zhao Qingping Xin Junkui Gao Junjun Shi Jin Zhong Huiguo Wang SINOPEC Research Institute of Petroleum Processing CO. LTD.Beijing 100083China state key laboratory of Separation Membranes and Membrane Processes/National Centre for International Joint Research on Separation Membranes Tiangong UniversityTianjin 300387China

Alginate is a natural polysaccharide *** filtration membranes prepared from alginate show excellent fouling resistance and controllable separation performance,but poor mechanical properties limit the use of algae *** this study,Ba^(2+)/Ca^(2+)co-crosslinked alginate(Ba/CaAlg)hydrogel membrane was prepared by cross-linking sodium alginate with a blend aqueous solution of barium ions and calcium ions,and the membrane was applied to the separation of dyes/salts from dyeing *** with the CaAlg membrane,the Ba/CaAlg hydrogel membrane exhibited more stable structure,and the mechanical properties and salt tolerance of the membrane were significantly *** flux of Ba/CaAlg membrane for methyl blue/sodium chloride mixed solution reached 43.5 L m^(−2) h^(−1),which was significantly higher than that of CaAlg ***,the Ba/CaAlg membrane showed higher dye rejection(>99.6%)and lower salt rejection(<8.2%).The structure of Ba/CaAlg membrane was preliminarily simulated by molecular dynamics,and the pore size and distribution of the membrane were *** Ba/CaAlg membrane has a broad application prospect in dyes/salts separation.

关键词： Alginate Filtration membrane Ba^(2+)/Ca^(2+)ion crosslinking Dye/salt separation Molecular dynamic simulation Hydrogel

预制体结构对SiC_(f)/SiC复合材料力学和热性能的影响

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Journal of Central South University 2024年第1期31卷 101-113页

作者：王徐辉吴宗绪陈招科伍艳熊翔 Science and Technology on High Strength Structural Materials laboratory Central South UniversityChangsha 410083China state key laboratory of Powder Metallurgy Central South UniversityChangsha 410083China

本文采用化学气相渗透法制备了具有二维多层、三维角联锁机织和多轴三维编织三种预制体结构的SiC_(f)/SiC复合材料。在综合分析纤维排列、SiC基体和孔隙分布的基础上,详细讨论了预制体结构对SiC_(f)/SiC复合材料力学性能和热性能的影响... 详细信息

本文采用化学气相渗透法制备了具有二维多层、三维角联锁机织和多轴三维编织三种预制体结构的SiC_(f)/SiC复合材料。在综合分析纤维排列、SiC基体和孔隙分布的基础上,详细讨论了预制体结构对SiC_(f)/SiC复合材料力学性能和热性能的影响。结果表明,复合材料的力学性能和热导率受纤维排列方式和复合材料密度的综合影响,而热膨胀系数主要受纤维排列方式的影响。此外,二维多层复合材料、三维角联锁机织复合材料和多轴三维编织复合材料的热导率可以分别用串联模型和平行模型来解释。多轴三维编织复合材料由于内部具有连续的可以作为热流快速通道的三维网状SiC基体层,因此具有较高的室温热导率。而随着温度的升高,SiC声子间的散射逐渐增强,SiC基体层在多轴三维编织复合材料中作为声子传播快速通道的作用逐渐减弱,热导率随温度降低的趋势更明显。

关键词：预制体结构抗弯强度热导率热膨胀系数 SiC_(f)/SiC复合材料

The Tibetan Plateau bridge:Influence of remote teleconnections from extratropical and tropical forcings on climate anomalies

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Atmospheric and Oceanic Science Letters 2024年第1期17卷 28-33页

作者： Yimin Liu Wei Yu Jilan Jiang Tingting Ma Jiangyu Mao Guoxiong Wu state key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina University of Chinese Academy of Sciences BeijingChina School of Atmospheric Sciences Sun Yat-sen UniversitySouthern Marine Science and Engineering Guangdong Laboratory(Zhuhai)ZhuhaiChina Guangdong Province key laboratory for Climate Change and Natural Disaster Studies Sun Yat-sen UniversityZhuhaiChina

本文回顾了青藏高原桥梁作用方面的最新研究进展,涉及北大西洋气候异常对春,夏亚洲季风和厄尔尼诺-南方涛动(ENSO)事件的遥相关影响,热带海洋异常和中国东部极端气候异常之间的联系以及华南春雨的季节内变化等.介绍了年际时间尺度上,冬... 详细信息

本文回顾了青藏高原桥梁作用方面的最新研究进展,涉及北大西洋气候异常对春,夏亚洲季风和厄尔尼诺-南方涛动(ENSO)事件的遥相关影响,热带海洋异常和中国东部极端气候异常之间的联系以及华南春雨的季节内变化等.介绍了年际时间尺度上,冬-春季北大西洋海表温度强迫如何影响南亚季风的季节性转变以及随后ENSO事件的触发.5月份青藏高原上空显著的负感热斜压结构,为北大西洋影响亚洲季风和ENSO提供了桥梁效应,夏季北大西洋涛动与华东夏季降水变化显著相关,高原潜热在这一关系中起着桥梁作用.另一方面,这种高原桥梁效应也存在于从热带海洋异常到东亚夏季极端降水事件的连接中,以及从中纬度波列到华南春雨准双周振荡的联系中.

关键词：青藏高原桥梁作用遥相关北大西洋厄尔尼诺-南方涛动热带对流气候异常和极端事件

Co-enhancement of thermal conduction and radiation through morphologies controlling of graphene functional layer for chip thermal management

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Nano Research 2024年第10期17卷 8885-8892页

作者： Shuting Cheng Kun Wang Shichen Xu Yi Cheng Ruojuan Liu Kewen Huang Hao Yuan Wenjuan Li Yuyao Yang Fushun Liang Fan Yang Kangyi Zheng Zhiwei Liang Ce Tu Mengxiong Liu Xiaomin Yang Jingnan Wang Xuzhao Gai Yuejie Zhao Xiaobai Wang Yue Qi Zhongfan Liu state key laboratory of Heavy Oil Processing College of ScienceChina University of PetroleumBeijing 102249China Centre for Nanochemistry Beijing Science and Engineering Centre for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Beijing Graphene Institute(BGI) Beijing 100095China College of Energy Soochow Institute for Energy and Materials Innovations(SIEMIS)Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy TechnologiesSoochow UniversitySuzhou 215006China Department of Chemistry College of Chemistry and Materials EngineeringBeijing Technology and Business UniversityBeijing 100048China

With the continuous advancements in electronics towards downsizing and integration,efficient thermal dissipation from chips has emerged as a critical factor affecting their lifespan and operational *** fan-less chip cooling system has two critical interfaces for thermal transport,which are the contact interface between the base and the chip dominated by thermal conduction,and the surface of the fins dominated by thermal *** different thermal transfer modes of these two critical interfaces pose different requirements for thermal management *** the study,a novel approach was proposed by developing graphene thermal transport functional material whose morphology could be intentionally designed via reformed plasmaenhanced chemical vapor deposition(PECVD)methods to meet the diverse requirements of heat transfer ***,graphene with multilevel branching structure of vertical graphene(BVG)was fabricated through the hydrogenassisted PECVD(H_(2)-PECVD)strategy,which contributed a high emissivity of~*** was deposited on the fins’surface and functioned as the radiation enhanced layer to facilitate the rapid radiation of heat from the heat sinks into the surrounding ***,the well-oriented vertical graphene(OVG)was successfully prepared through the vertical electric field-assisted PECVD process(EF-PECVD),which showed a high directional thermal conductivity of~53.5 W·m^(-1)·K^(-1).OVG was deposited on the contact interface and functioned as the thermal conduction enhanced layer,allowing for the quick transmission of heat from the chip to the heat *** this design concept,the two critical interfaces in the chip cooling system can be jointly enhanced,resulting in a remarkable cooling efficiency enhancement of~30.7%,demonstrating that this novel material possessed enormous potential for enhancing the performance of cooling ***,this research not only provided new design concepts for the cooling system

关键词： chip thermal management thermal conduction thermal radiation graphene morphology control