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Highly Improved Creep Resistance in Polypropylene Through Thermally Reduced Graphene Oxide and Its Creep Lifetime Prediction

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Chinese Journal of Polymer Science 2024年第2期42卷 256-266,I0010页

作者： Can-Can Zhang Jun-Long Yang Ya-Jiang huang Guang-xian Li College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering of ChinaSichuan UniversityChengdu610065China

Polypropylene(PP) exhibits suboptimal creep resistance due to the presence of methyl groups on its main chain, leading to irregular chain segment distribution, diminished inter-chain interaction, and crystallinity. This structural feature causes chain slippage in PP under stress,significantly constraining its service lifetime. In this study, thermally reduced graphene oxide(TrGO) nanosheets were incorporated into the PP matrix, yielding a nanocomposite with exceptional creep resistance performance. Results demonstrated that at a stress of 25 MPa, a 2.0 wt% TrGO content could enhance the creep failure lifetime of PP by 21.5 times compared to neat PP. Rheology, transmission electron microscopy(TEM),and scanning electron microscopy(SEM) characterization techniques were employed to analyze the mechanism of TrGO's influence on PP's creep behavior. It was observed that when TrGO content exceeded 1.0 wt%, an effective particle network structure formed within the PP matrix. This homogeneously dispersed TrGO-formed particle network structure restricted the migration and rearrangement of PP molecular chains, enabling prolonged stress resistance without structural failure. By combining the time-strain superposition method with the critical failure strain as a criterion, generalized creep compliance curves for PP and its composites were established, facilitating the prediction of material creep failure lifetimes, with a strong agreement between experimental and predicted lifetime values. This research proposes a novel strategy aimed at developing polypropylene materials and products with enhanced long-term stability and durability, thus extending service life, reducing failure risk, and broadening their potential across various application domains.

关键词： Thermally reduced graphene oxide Polypropylene Creep failure and lifetime prediction

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Geographical features and development models of estuarine cities

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Journal of Geographical Sciences 2024年第1期34卷 25-40页

作者： CHEN Mingxing xian Yue huang Yaohuan SUN Zhigang WU Chengbin Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China College of Resource and Environment University of Chinese Academy of SciencesBejing 100049China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China Zhongke Shandong Dongying Institute of Geography Dongying 257509ShandongChina CAs Engineering Laboratory for Yellow River Delta Modern Agriculture Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China

Cities are the key areas for human beings to achieve sustainable development goals in the future.Estuarine cities are a special type of coastal city in urgent need of a clear definition.This paper proposed that estuarine cities are cities developed on the coast where rivers and oceans meet and defined four connotations,including the intersection of rivers and marine water systems,the coordinated development of land and oceans,the location advantages of connecting rivers and seas,and the important fragility of the ecological environment.We used Hydro SHEDS,OSM,GPW,and urban socioeconomic statistics and selected 50 estuarine cities with large rivers as representatives to summarize the main geographical basis and socioeconomic characteristics.Cities are primarily found in low-altitude,flat regions with average annual temperatures that mainly vary from 10℃to 25℃,relatively abundant precipitation,and extensive biological resources.There are substantial variations in the socioeconomic features of estuarine cities.We proposed eight development patterns,including open and inclusive city spirit,high-quality livable cities,high-quality development driven by innovation,integration of internal and external communication with ports and cities,construction of an international financial center,ecological environment protection and restoration,active promotion of cultural tourism,and positive international exchanges.

关键词： estuarine cities great rivers development models sustainability physical geography socioeconomy

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

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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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Crosstalk between glioblastoma and tumor microenvironment drives proneural–mesenchymal transition through ligand-receptor interactions

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Genes & Diseases 2024年第2期11卷 874-889页

作者： Yancheng Lai Xiaole Lu Yankai Liao Pei Ouyang Hai Wang xian Zhang Guanglong huang Songtao Qi Yaomin Li Department of Neurosurgery Institute of Brain DiseaseNanfang HospitalSouthern Medical UniversityGuangzhouGuangdong 510515China Laboratory for Precision Neurosurgery Nanfang HospitalSouthern Medical UniversityGuangzhouGuangdong 510515China

Glioblastoma(GBM)is the most common intrinsic and aggressive primary brain tumor in adults,with a median survival of approximately 15 months.GBM heterogeneity is considered responsible for the treatment resistance and unfavorable prognosis.Proneural-mesenchymal transition(PMT)represents GBM malignant progression and recurrence,which might be a breakthrough to understand GBM heterogeneity and overcome treatment resistance.PMT is a complicated process influenced by crosstalk between GBM and tumor microenvironment,depending on intricate ligand-receptor interactions.In this review,we summarize the autocrine and paracrine pathways in the GBM microenvironment and related ligand-receptor interactions inducing PMT.We also discuss the current therapies targeting the PMT-related autocrine and paracrine pathways.Together,this review offers a comprehensive understanding of the failure of GBM-targeted therapy and ideas for future tendencies of GBM treatment.

关键词： Autocrine Glioblastoma Ligand-receptor interaction Microenvironment Paracrine Proneural-mesenchymal transition

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Experimental Study on Mixed-Mode(Ⅰ–Ⅱ)Fracture Toughness of Freshwater Ice

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Acta Mechanica Solida Sinica 2024年第2期37卷 252-264页

作者： Yaozhong Xu Mao Zhou xian Yi Wen Hua Jiuzhou huang Wenyu Zhang Shiming Dong Key Laboratory of Deep Underground Science and Engineering Ministry of EducationCollege of Architecture and EnvironmentSichuan UniversityChengdu610065China Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province Sichuan UniversityChengdu610065China China Aerodynamics Research and Development Center/Low Speed Aerodynamics Research Institute Mianyang621000China College of Mechanical and Electrical Engineering Xichang UniversityXichang615000China

Ⅰn recent years,the issue of aircraft icing has gained widespread recognition.The breaking and detachment of dynamic ice can pose a threat to flight safety.However,the shedding and fracture mechanisms of dynamic ice are unclear and cannot meet the engineering needs of ice-shedding hazard assessment.Therefore,studying the fracture toughness of ice bodies has extremely important practical significance.To address this issue,this article uses a centrally cracked Brazilian disk(CCBD)specimen to measure the pure mode Ⅰ toughness and pure mode Ⅱ fracture toughness of freshwater ice at different loading rates.The mixed-mode(Ⅰ–Ⅱ)fracture characteristics of ice are discussed,and the experimental results are compared and analyzed with the theoretical values of the generalized maximum tangential stress(GMTS)criterion considering the influence of T-stress.The results indicated that as the loading rate increases,the pure mode Ⅰ toughness and pure mode Ⅱ fracture toughness of freshwater ice decrease,and the fracture toughness of freshwater ice is more sensitive to the loading rate.Ⅰn terms of fracture criteria,the theoretical value of the ratio of pure mode Ⅱ fracture toughness to pure mode Ⅰ fracture toughness based on the GMTS criterion is in good agreement with the experimental value,while the theoretical value based on the maximum tangential stress(MTS)criterion deviates significantly from the experimental value,indicating that the GMTS criterion considering the influence of T-stress can better predict the experimental results.

关键词： Freshwater ice Fracture criteria Centrally cracked Brazilian disk(CCBD) Mixed-mode(Ⅰ-Ⅱ) Loading rate

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The role of acute normovolemic hemodilution in reducing allogeneic blood transfusion in glioblastoma surgery:a case-control study

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Chinese Neurosurgical Journal 2024年第1期10卷 35-41页

作者： Ping Chen Xin‑huang Zhang Ying Wang xian‑Zhong Lin De‑Zhi Kang Qing‑Song Lin Department of Anesthesiology The First Affiliated Hospital of Fujian Medical UniversityFuzhou 350005FujianChina Department of Neurosurgery The First Affiliated Hospital of Fujian Medical UniversityNo.20 Chazhong RdTaijiang DistrictFuzhou 350005FujianChina Department of Neurosurgery Binhai Branch of National Regional Medical CenterThe First Affiliated Hospital of Fujian Medical UniversityFuzhou 350209FujianChina Fujian Provincial Institutes of Brain Disorders and Brain Sciences The First Affiliated Hospital of Fujian Medical UniversityFuzhou 350005FujianChina Fujian Provincial Clinical Research Center for Neurological Diseases The First Affiliated Hospital of Fujian Medical UniversityFuzhou 350005FujianChina Fujian Provincial Key Laboratory of Precision Medicine for Cancer The First Affiliated Hospital of Fujian Medical UniversityFuzhou 350005FujianChina

Background Acute normovolemic hemodilution(ANH)was first introduced in glioblastoma surgery,and its role in reducing allogeneic blood transfusion was investigated in this study.Methods This study enrolled supratentorial glioblastoma patients who received total resection.In the ANH group,the patients were required to draw blood before the operation,and the blood will be transfused back to the patient during the operation.The association between ANH and clinical features was investigated.Results Sixty supratentorial glioblastoma patients were enrolled in this study,25 patients were allocated in the ANH group,and another 35 patients were included in the control group.ANH dramatically reduced the need for allogeneic blood transfusion(3[12%]vs 12[34.3%],P=0.049),and the blood transfusion per total of patients was dramatically decreased by the application of ANH(0.40±1.15 units vs 1.06±1.59 units,P=0.069).Furthermore,ANH also markedly reduced the requirement of fresh frozen plasma(FFP)transfusion(2[8%]vs 11[31.4%],P=0.030)and the volume of FFP transfusion per total of patients(32.00±114.46 mL vs 115.71±181.00 mL,P=0.033).The complication rate was similar between the two groups.Conclusions ANH was a safe and effective blood conservation technique in glioblastoma surgery.

关键词： Glioblastoma Acute normovolemic hemodilution Surgery Blood transfusion

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Highly Hydrolysis-Resistant Polyimide Fibers Prepared by Thermal Crosslinking with Inherent Carboxyl Groups

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Chinese Journal of Polymer Science 2024年第2期42卷 247-255,I0010页

Easy hydrolysis in alkaline environments limits the use of polyimide fibers in environmental protection. The hydrolysis resistance levels of polyimide fibers can be improved by crosslinking of the macromolecular chains. In this work, crosslinked polyimide fibers(CPI fibers) were produced by intrinsic carboxyl decarboxylation for the first time. The thermal stability of the polyimide fibers containing the intrinsic carboxyl groups(PIC fibers) was studied, and the temperature of the decarboxylation-crosslinking reaction was determined to be 450 ℃. The PIC fibers were hotdrawn to initiate thermal crosslinking of the carboxyl groups and molecular chain orientation at high temperature. The CPI fibers had high tensile strengths(0.72-1.46 GPa) and compressive strengths(401-604 MPa). The oriented macromolecules and chemically crosslinked structure improved the tightness of the molecular chains and endowed the CPI fibers with excellent hydrolytic resistance. The CPI-50 fiber did not dissolve in a 0.5 wt% NaOH solution during heating at 90 ℃ for 10 h, and the tensile strength retention reached 87% when treated in 0.5 wt% NaOH solutions at 90 ℃ for 1 h, providing a guarantee for its application in alkaline corrosive environments.

关键词： Polyimide Carboxyl group Crosslinking Hydrolysis-resistance

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Engineering high-performance dielectric chiral shells with enhanced chiral fields for sensitive chiral biosensor

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Rare Metals 2024年第3期43卷 1197-1206页

作者： Yi-Fan Wang Shan-Shan huang Zhen-Dong Dai Shi-Lin xian Xuan-Nan Wu Fu-Hua Gao Yi-Dong Hou College of Physics Sichuan UniversityChengdu610065China Graduate School of Sichuan University Sichuan UniversityChengdu610065China

Chiral metamaterials have been a topic of significant research interest in recent years due to their potential for various applications in nanophotonic devices and chiral biosensors.However,the intrinsic Ohmic loss in surface plasmonic resonance has limited their practical use,resulting in large light dissipation and weak chiroptical resonance.Here,we report on the development of high-performance dielectric chiral shells(DCS)through a two-step Si deposition process on a self-assembled microsphere monolayer.The form DCS sample completely oyercomes the cancelation effect originated from the disorder property of the micro-sphere monolayer in macroscale,and at a wavelength of approximately 710 nm,the measured optimal chiral signal(g-factor)and transmittance can reach up to 0.7 and 0.3,respectively.The strong chiroptical effect comes from the asymmetric circular displacement currents(i.e.,magnetic modes)enabled by the specific shell geometry.The chiral shell geometry,electromagnetic properties,sensor sensitivity of chiral molecules and figure of merit are systematically investigated.The DCSs demonstrate highly sensitive detection of chiral biomolecules owing to their easily accessible geometry and enhanced uniform chiral field.

关键词： Dielectric chiral shells(DCS) Si deposition Magnetic resonance Highly sensitive sensor Chiral field

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Prediction of suitable water content in granulation of sintering mixture based on Litster's model

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Journal of Iron and Steel Research(International) 2024年第3期31卷 552-560页

作者： Fang-lei Dai Xiao-hui Fan Xiao-xian huang Xu-ling Chen Min Gan Zhi-yun Ji Zeng-qing Sun School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083HunanChina

Suitable water content plays a decisive role in the granulation of sintering mixtures.Herein,a method was proposed to predict the suitable water content for effective granulation on the basis of Litster's granulation model.The granulation effectiveness of a sintering mixture was predicted by the model,with the allowance error of±10%.The effects of the water absorption properties,particle size composition and content of adhesive particles on the suitable water content were studied.The results showed that the allowable error of prediction was within±0.5%compared to the experimentally determined suitable water content.With an increase in adhesive powder content of mixtures with higher water absorption,the suitable water content increased to achieve similar granulation effectiveness.Moreover,as the amount of concentrates increased,the suitable water content first increased and then remained steady.The influence of the water absorption characteristics of the adhesive particles on the suitable water content was less than that of their particle size composition in the mixture.

关键词： Adhesive particle Sintering mixture Granulation effectiveness Suitable water content

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A micro-crosslinked amphoteric hydrophobic association copolymer as high temperature-and salt-resistance fluid loss reducer for water-based drilling fluids

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Petroleum Science 2024年第3期21卷 1980-1991页

作者： Jian Li Yu-Xi Ji Xiao-Xiao Ni Kai-He Lv xian-Bin huang Jin-Sheng Sun School of Petroleum Engineering China University of Petroleum(East China) Key Laboratory of Unconventional Oil & Gas Development China University of Petroleum(East China) Inspection and Testing Center of Huabei Oil Field Company PetroChina Drilling Fluid Research Institute CNPC Engineering Technology R&D Company Limited

During ultradeep oil and gas drilling, fluid loss reducers are highly important for water-based drilling fluids, while preparing high temperature-and salt-resistance fluid loss reducers with excellent rheology and filtration performance remains a challenge. Herein, a micro-crosslinked amphoteric hydrophobic association copolymer(i.e., DADC) was synthesized using N,N-dimethyl acrylamide, diallyl dimethyl ammonium chloride, 2-acrylamido-2-methylpropane sulfonic acid, hydrophobic monomer, and pentaerythritol triallyl ether crosslinker. Due to the synergistic effects of hydrogen bonds, electrostatic interaction, hydrophobic association, and micro-crosslinking, the DADC copolymer exhibited outstanding temperature-and salt-resistance. The rheological experiments have shown that the DADC copolymer had excellent shear dilution performance and a certain degree of salt-responsive viscosity-increasing performance. The DADC copolymer could effectively adsorb on the surface of bentonite particles through electrostatic interaction and hydrogen bonds, which bring more negative charge to the bentonite, thus improving the hydration and dispersion of bentonite particles as well as the colloidal stability of the drilling fluids. Moreover, the drilling fluids constructed based on the DADC copolymer exhibited satisfactory rheological and filtration properties(FLHTHP= 12 m L) after aging at high temperatures(up to200°C) and high salinity(saturated salt) environments. Therefore, this work provided new insights into designing and fabricating high-performance drilling fluid treatment agents, demonstrating good potential applications in deep and ultradeep drilling engineering.

关键词： Fluid loss reducer Temperature- and salt-resistance Hydrophobic association Amphoteric Micro-crosslinking

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