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Exploring the Interplay between Local Chain Structure and Stress Distribution in Polymer Networks

Chinese Journal of Polymer Science 2024年第6期42卷 874-885页

作者： Jin-Tong Xue Yang Bai Li Peng xian-bo huang Zhao-Yan Sun School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China National-certified Enterprise Technology Center Kingfa Science and Technology Co.Ltd.Guangzhou510663China

The mechanical behavior of polymer networks is intrinsically correlated with the local chain topology and chain connectivity.In this study,we delve into this relationship through the lens of coarse-grained molecular dynamics(CG-MD)simulations.Our aim is to illuminate the intricate interplay between local topology and stress distribution within polymer monomers,cross-linkers,and various components with distinct cross-link connections,thereby elucidating their collective impact on the mechanical properties of polymer networks.We mainly focus on how specific local structures contribute to the overall mechanical response of the network.In particular,we employ local stress analysis to unravel the mechanics of these structures.Our findings reveal the diverse responses of individual components,such as junctions,strands,cross-linkers between junctions,and dangling chain ends,when subjected to stretching.Notably,we observe that these components exhibit varying degrees of deformation tolerance,underscoring the significance of their roles in determining the mechanical characteristics of the network.Our investigations highlight junctions as primary contributors to stress accumulation,and particles with higher local stress showing a stronger correlation between stress and Voronoi volume.Moreover,our results indicate that both strands and cross-linkers between junctions exhibit heightened stress levels as strand lengths decrease.This study enhances our understanding of the multifaceted factors governing the mechanical attributes of cross-linked polymer systems at the microstructural level.

关键词： Local chain structure Local stress Molecular dynamics simulation

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The Crystallization Behavior Regulating Nature of Hydrogen bonds Interaction on Polyamide 6,6 by Poly(vinyl pyrrolidone)

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Chinese Journal of Polymer Science 2023年第3期41卷 394-404,I0008页

作者： Yang Liu Li Peng Jie-Long Lin Yong Zhou Du-Jin Wang Charles C.Han xian-bo huang Xia Dong National-certified Enterprise Technology Center Kingfa Science and Technology Co.LTD.Guangzhou 510663China CAS Key Laboratory of Engineering Plastics Beijing National Laboratory for Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBejing 100190China University of Chinese Academy of Sciences Beijing 100049China

The crystallization behavior of polyamide 6,6(PA66) under complex flow field is of great importance for its final mechanical properties.Poly(vinyl pyrrolidone)(PVP) was applied as crystallization modifying agency to improve processability of PA66.The regulation nature on hydrogen bonds(H-bonds) interaction of PVP was studied upon cooling process.As revealed by in situ FTIR,the sample with 5 wt% PVP displays decreased enthalpy change(ΔH) for both the generation of H-bonds and the transition of H-bonds from “disordered” to “ordered” state,which illustrates the molecular mechanism for the regulation of crystallzation behavior.Moveover,2D-WAXD is applied to reveal the evolution of microstructure for sample under external injection field.Hermans orientation factor(f_(H)) decreases obviously with the addition of PVP,because the relaxation of chain segments is promoted as well the crystallization is retarded.The above crystallization and microstructure changes during the processing provokes the improvement of processability without the apparent sacrifice of mechanical properties.

关键词： Polyamide 66 Poly(vinyl pyrrolidone) Hydrogen bonds interaction

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Current rice production is highly vulnerable to insect-borne viral diseases

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National Science Review 2022年第9期9卷 142-144页

作者： Jian-guo Wu Guo-yi Yang Shan-shan Zhao Shuai Zhang Bi-xia Qin Yong-sheng Zhu Hui-ting Xie Qing Chang Lu Wang Jie Hu Chao Zhang Bao-gang Zhang Da-li Zeng Jian-fu Zhang xian-bo huang Qian Qian Shou-wei Ding Yi Li Vector-borne Virus Research Center Fujian Province Key Laboratory of Plant Virology Institute of Plant Virology Fujian Agriculture and Forestry University Institute of Plant Protection Guangxi Academy of Agricultural Sciences Rice Research Institute Fujian Academy of Agricultural Sciences State Key Laboratory of Rice Biology China National Rice Research InstituteChinese Academy of Agricultural Sciences Rice Research Institute Sanming Academy of Agricultural Sciences Department of Microbiology and Plant Pathology Center for Plant Cell Biology Institute for Integrative Genome Biology University of California The State Key Laboratory of Protein and Plant Gene Research School of Life Sciences Peking University

Rice is one of the most important food crops and feeds more than half of the world’s population [1]. Arthropod-borne rice viruses have caused devastating epidemics in Asian countries and are a major threat to food security [2]. However,lile is known about the vulnerability of rice crops to viral pathogens [3,4], especially southern rice black-streaked dwarf virus (SRBSDV), rice black-streaked dwarf virus (RBSDV) and rice gall dwarf virus (RGDV), known to induce annual outbreaks by insect transmission in some localities in Asia.

关键词： INSIGHTS IMMUNITY

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Access to High-Molecular-Weight Polyethylenes through High Temperature Ethylene Polymerization Catalysed by Ethylene-Bridged ansa-(3-R-Cyclopentadienyl)(Fluorenyl) Zirconocene Complexes

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Chinese Journal of Polymer Science 2024年第1期42卷 42-51,I0007页

作者： bo Li Haiyan Ma Jiling huang Shanghai Key Laboratory of Functional Materials Chemistry and Laboratory of Organometallic Chemistry School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

A series of C1-symmetric ethylene-bridged ansa-(3-R-cyclopentadienyl)(fluorenyl) metallocene complexes(Zr: 1-5;Hf: 6) have been synthesized, characterized and investigated as catalyst precursors for the high temperature ethylene polymerization. Using methylaluminoxane(MAO) as the cocatalyst, zirconium complexes 1-5 bearing a bulky substituent on the 3-position of the cyclopendienyl ring showed high catalytic activities up to 1.48×10^(7) g PE·mol_(Zr)^(-1)·h^(-1) toward the polymerization of ethylene and afforded polyethylenes with high molecular weights(1.49×10^(5)-6.31×10^(5) g/mol), meanwhile exhibting great thermal stability at high temperatures up to 120 ℃ together with a long catalytic life time up to 2 h. By adopting low Al/Zr ratios, such as 125, polyethylenes with ultra high molecular weights up to 2.86×106 g/mol were obtained. It is worthy of noting that zirconium complexes 1-4 bearing a substituent with an aryl pendant showed temperature-dependent activities, which increased rapidly with the increase of polymerization temperature, thus weak interaction of the pendent aryl group with the cationic active center is proposed to account for the very low activities displayed at low temperatures. In contrast to zirconocene complexes 1-5, hafnocene complex 6 only displayed very low catalytic activities toward the polymerization of ethylene and afforded polyethylenes with molecular weights ten times smaller than those obtained by zirconocene complexes 1-5. Zirconocene complexes 1-5 were also able to catalyse the polymerization of propylene at high temperatures, but only afforded waxes with low molecular weights.

关键词： ansa-Metallocene Ethylene Propylene Polymerization High temperature

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流变技术在高分子表征中的应用:拉伸流变测试

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高分子学报 2023年第2期54卷 286-302页

作者：刘双黄茜陈全黄险波四川大学高分子材料工程国家重点实验室、高分子研究所成都610065 金发科技股份有限公司企业技术中心广州510000 中国科学院长春应用化学研究所、高分子物理与化学国家重点实验室长春130022

流变测试是与高分子加工和应用相关的重要表征手段.尤其在纺丝、发泡、吹膜、吹塑等以拉伸流场占主导的高分子加工工艺中,高分子的拉伸流变行为对材料聚集态结构的形成起了决定性的作用,进而影响了产品最终的使役性能.本综述第一部分介... 详细信息

流变测试是与高分子加工和应用相关的重要表征手段.尤其在纺丝、发泡、吹膜、吹塑等以拉伸流场占主导的高分子加工工艺中,高分子的拉伸流变行为对材料聚集态结构的形成起了决定性的作用,进而影响了产品最终的使役性能.本综述第一部分介绍了拉伸流场的定义、拉伸流场的分类以及各自的特征;第二部分概述了目前商业拉伸流变仪的种类,并围绕其基本原理、测试技巧以及优缺点等内容展开讲解;第三部分介绍了拉伸流变的测试模式,并举例说明了各个模式的优势;第四部分列出了在拉伸测试中存在的常见问题,并给出了相应的解决方案和建议;最后对拉伸流变与其他表征联用技术的发展趋势进行了总结和展望.

关键词：流变学拉伸流场拉伸流变仪拉伸测试

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Chemical modification of barite for improving the performance of weighting materials for water-based drilling fluids

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Petroleum Science 2024年第1期21卷 551-566页

作者： Li-Li Yang Ze-Yu Liu Shi-bo Wang xian-bo He Guan-Cheng Jiang Jie Zhang MOE Key Laboratory of Petroleum Engineering State Key Laboratory of Petroleum Resources and ProspectingChina University of Petroleum(Beijing)Changping DistrictBeijing102249China MOE Key CNPC Drilling Research Institute Changping DistrictBeijing102206China

With increasing drilling depth and large dosage of weighting materials,drilling fluids with high solid content are characterized by poor stability,high viscosity,large water loss,and thick mud cake,easier leading to reservoir damage and wellbore instability.In this paper,micronized barite(MB)was modified(mMB)by grafting with hydrophilic polymer onto the surface through the free radical polymerization to displace conventional API barite partly.The suspension stability of water-based drilling fluids(WBDFs)weighted with API barite:mMB=2:1 in 600 g was significantly enhanced compared with that with API barite/WBDFs,exhibiting the static sag factor within 0.54 and the whole stability index of 2.The viscosity and yield point reached the minimum,with a reduction of more than 40%compared with API barite only at the same density.Through multi-stage filling and dense accumulation of weighting materials and clays,filtration loss was decreased,mud cake quality was improved,and simultaneously it had great reservoir protection performance,and the permeability recovery rate reached 87%.In addition,it also effectively improved the lubricity of WBDFs.The sticking coefficient of mud cake was reduced by 53.4%,and the friction coefficient was 0.2603.Therefore,mMB can serve as a versatile additive to control the density,rheology,filtration,and stability of WBDFs weighted with API barite,thus regulating comprehensive performance and achieving reservoir protection capacity.This work opened up a new path for the productive drilling of extremely deep and intricate wells by providing an efficient method for managing the performance of high-density WBDFs.

关键词： Drilling fluids Weighting materials Filtration control Reservoir protection Stability property

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Effect of Texture on the Grain-Size-Dependent Functional Properties of NiTi Shape Memory Alloys and Texture Gradient Design:A Phase Field Study

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Acta Mechanica Solida Sinica 2024年第1期37卷 10-32页

作者： bo Xu Beihai huang Chong Wang Qingyuan Wang Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan ProvinceSichuan UniversityChengdu 610065China Department of Mechanical Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Key Laboratory of Deep Underground Science and Engineering Ministry of EducationSichuan UniversityChengdu 610065China

Texture is inevitably introduced during the manufacturing of most NiTi shape memory alloys(SMAs),and the textured nanocrystalline NiTi has been extensively employed in engineering.However,the effect of texture,and the joint effect of grain size(GS)and texture on the functional properties of NiTi SMAs and the corresponding microscopic mechanisms have not been clearly understood yet.In this work,based on the phase field method,the effect of texture on the GS-dependent functional properties of NiTi SMAs,including super-elasticity(SE),one-way shape memory effect(OWSME),and stress-assisted two-way shape memory effect(SATWSME),is investigated,and the corresponding microscopic mechanisms are revealed.Moreover,the samples with discrete geometrical gradients and/or texture gradients are designed to achieve graded functional properties.The simulation results indicate that the dependence of functional properties on texture is due to the effect of crystallographic orientation on martensite transformation and reorientation,which can lead to different inelastic strains.In the designed samples with texture gradients,the stress–strain responses of sheets with various textures are different,allowing for the coordination of overall deformation of the sample by combining such sheets,with varying inelastic deformation degrees.Thus,the overall response of the sample differs from that without texture gradient,leading to the achievement of graded functional properties.The simulation results and new findings in this work contribute to a deeper understanding of the effects of texture,GS,and their interaction on the functional properties of SMAs,and provide valuable reference for the design and development of SMA-based devices with desired functional properties.

关键词： Phase field NiTi shape memory alloy Texture Grain size Functional property Texture gradient

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Cytoplasmic FKBPs are involved in molting and metamorphosis through regulating the nuclear localization of EcR

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Insect Science 2024年第3期31卷 759-772页

作者： xian Zhang Qiao-Ran Wang Qian Wu Jun Gu Li-Hua huang Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology School of Life SciencesSouth China Normal UniversityGuangzhouChina Guangmeiyuan R&D Center Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied TechnologySouth China Normal UniversityMeizhouChina

Molting and metamorphosis are important physiological processes in insects that are tightly controlled by ecdysone receptor(EcR)through the 20-hydroxyecdysone(20E)signaling pathway.EcR is a steroid nuclear receptor(SR).Several FK506-binding proteins(FKBPs)have been identified from the mammal SR complex,and are thought to be involved in the subcellular trafficking of SR.However,their roles in insects are poorly understood.To explore whether FKBPs are involved in insect molting or metamorphosis,we injected an FKBP inhibitor(FK506)into a lepidopteran insect,Spodoptera litura,and found that molting was inhibited in 61.11%of the larvae,and that the time for larvae to pupate was significantly extended.A total of 10 FKBP genes were identified from the genome of s.litura and were clustered into 2 distinct groups,according to their subcellular localization,with FKBP13 and FKBP14 belonging to the endoplasmic reticulum(ER)group and with the other members belonging to the cytoplasmic(Cy)group.All the CyFKBPs were significantly upregulated in the prepupal or pupal stages,with the opposite being observed for the ER group members.FK506 completely blocked the transfer of EcR to the nucleus under 20E induction,and significantly downregulated the transcriptional expression of many 20E signaling genes.A similar phenomenon was observed after RNA interference of2 CyFKBPs(FKBP45 and FKBP12b),but not for FKBP13.Taken together,our data indicate that the cytoplasmic FKBPs,especially FKBP45 and FKBP12b,mediate the nuclear localization of EcR,thereby regulating the 20E signaling and ultimately affecting molting and metamorphosis in insects.

关键词： EcR FKBP metamorphosis molting RNAi subcellular localization

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Ultra-high energy cosmic neutrinos from gamma-ray bursts

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Fundamental Research 2024年第1期4卷 51-56页

作者： Yanqi huang bo-Qiang Ma School of Physics Peking UniversityBeijing 100871China Center for High Energy Physics Peking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China

Based on the recent association of IceCube TeV and PeV neutrino events with gamma-ray bursts(GRBs)by considering the Lorentz violation of neutrinos,we provide a new estimate on the GRB neutrino flux with a more significant result compared to the previous constraint by the IceCube Collaboration.Among these 24 neutrino“shower”events above 60 TeV,12 events are associated with GRBs.Such a result is compatible with the prediction from GRB fireball models.Analysis of track events provides a consistent result with the shower events to associate high energy cosmic neutrinos with GRBs under the same Lorentz violation features of neutrinos.We also make a background estimation and reveal GRBs as a significant source for the ultra-high energy IceCube neutrino events.Our work supports the Lorentz violation and CPT-violation of neutrinos,indicating new physics beyond relativity.

关键词： Cosmic neutrino Gamma-ray burstLorentz invariance violation Neutrino and anti-neutrino asymmetry CPT-violation of neutrinos

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Metabolic plasticity of T cell fate decision

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中华医学杂志(英文版) 2024年第7期137卷 762-775页

作者： Pan Xiaoli Wang Jiajia Zhang Lianjun Li Guideng huang bo Institute of Basic Medical Sciences Chinese Academy of Medical Sciences (CAMS) & Beijing 100005 National Key Laboratory of Immunity and Inflammation Suzhou Institute of Systems Medicine Chinese Academy of Medical Sciences & Peking Union Medical College Suzhou Jiangsu 215123 China Department of Immunology & National Key Laboratory of Medical Molecular Biology

The efficacy of adaptive immune responses in cancer treatment relies heavily on the state of the T cells. Upon antigen exposure, T cells undergo metabolic reprogramming, leading to the development of functional effectors or memory populations. However, within the tumor microenvironment (TME), metabolic stress impairs CD8+ T cell anti-tumor immunity, resulting in exhausted differentiation. Recent studies suggested that targeting T cell metabolism could offer promising therapeutic opportunities to enhance T cell immunotherapy. In this review, we provide a comprehensive summary of the intrinsic and extrinsic factors necessary for metabolic reprogramming during the development of effector and memory T cells in response to acute and chronic inflammatory conditions. Furthermore, we delved into the different metabolic switches that occur during T cell exhaustion, exploring how prolonged metabolic stress within the TME triggers alterations in cellular metabolism and the epigenetic landscape that contribute to T cell exhaustion, ultimately leading to a persistently exhausted state. Understanding the intricate relationship between T cell metabolism and cancer immunotherapy can lead to the development of novel approaches to improve the efficacy of T cell-based treatments against cancer.

关键词： T cell immunotherapy T cell differentiation T cell exhaustion Metabolic reprogramming Tumor microenvironment

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