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Chinese Journal of Polymer Science 2024年第3期42卷 352-363,I0008页

作者： Yuan Ji Shi-Da Han Hong Wu shao-yun guo Feng-Shun Zhang Jian-Hui Qiu The State Key Laboratory of Polymer Materials Engineering Sichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyPolymer Research InstituteSichuan UniversityChengdu 610065China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China Department of Mechanical Engineering Faculty of Systems Science and TechnologyAkita Prefectural UniversityAkita 015-0055Japan

Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impedance as the main bottleneck limiting the performance of TIMs is usually neglected. Herein, the thermal impedance of SR composites loaded with different levels of hexagonal boron nitride(h-BN) as TIMs was elaborated for the first time by the ASTM D 5470 standard test and finite element analysis. It was found that elastic modulus and surface roughness of SR composites increased with the increase of h-BN content, indicating that the conformity was reduced. When the assembly pressure was 0.69 MPa, there existed an optimal h-BN content at which the contact resistance was minimum(0.39 K·cm^(2)·W^(-1)). Although the decreased bond line thickness(BLT) by increasing the assembly pressure was beneficial to reduce the thermal impedance, the proper assembly pressure should be selected to prevent the warpage of the contact surfaces and the increase in contact resistance, according to the compression properties of the SR composites. This study provides valuable insights into fabrication of high-performance TIMs for modern electronic device applications.

关键词： Thermal interface materials Hexagonal boron nitride Thermal impedance Surfaces

Bilayer Compounded Polytetrafluoroethylene Membrane for Enhanced Oil-Water Emulsion Separation

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Chinese Journal of Polymer Science 2024年第6期42卷 838-850页

作者： Yu-Liang Yang Tai-Ran Zhang Yan-Ting Han shao-yun guo Qin-Gong Rong Jia-Bin Shen State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversitySichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyChengdu610065China West China Hospital/West China School of Nursing Sichuan UniversityChengdu610041China Shandong Senrong New Materials Co. Ltd.Zibo256401China

In order to achieve efficient and durable oil-water emulsion separation,the membranes possessing high separation efficiency and mechanical strength attract extensive attention and are in great demand.In present study,a kind of polytetrafluoroethylene(PTFE)-based bilayer membrane was fabricated by electrospinning fibrous PTFE(fPTFE)on an expanded PTFE(ePTFE)substrate.The morphological observation revealed that the fibrous structure of the fPTFE layer could be tailored by controlling the formulation of spinning solution.The addition of appropriate polyoxyethylene(PEO)would make the fibers in the fPTFE layer finer and more uniform.As a result,the compounded membrane exhibited a small pore size of approximately 1.25µm and a substantial porosity nearing 80%.This led to super-hydrophobicity,characterized by a high water contact angle(WCA)of 149.8°,and facilitated rapid oil permeation.The water-in-oil emulsion separation experiment further confirmed that the compounded membrane not only had a high separation efficiency closing 100%,but such an outstanding separation capacity could be largely retained,either through multiple cycles of use or through strong acid(pH=1),strong alkali(pH=12),or high-temperature(100°C)treatment.Additionally,the mechanical behavior of the bilayer membrane was basically contributed by that of each layer in terms of their volume ratio.More significantly,the poor creep resistance of fPTFE layer was suppressed by compounding with ePTFE substrate.Hence,this study has laid the groundwork for a novel approach to create PTFE-based compounded membranes with exceptional overall characteristics,showing promise for applications in the realm of emulsion separation.

关键词： ePTFE Electrospinning membrane Bilayer compounding Emulsion separation

Flame-retardant and Self-healing Biomass Aerogels Based on Electrostatic Assembly

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Chinese Journal of Polymer Science 2020年第12期38卷 1294-1304页

作者： Ji-Yu Yang Yu Xia Jin Zhao Long-Fei Yi Yong-Jiao Song Hong Wu shao-yun guo Li-Juan Zhao Jin-Rong Wu College of Chemistry and Materials Science Sichuan Normal UniversityChengdu 610066China State Key Laboratory ofPolymer Materials Engineering Polymer Research InstituteSichuan UniversityChengdu 610065China State Key Laboratory ofPolymer Materials Engineering Collegeof Polymer Science and EngineeringSichuan UniversityChengdu 610065China

It remains a significant challenge to fabricate self-healing aerogels with excellent flame retardancy.Herein,we develop a class of biomass aerogels by electrostatically assembling chitosan(CS),phytic acid(PA),and itaconic acid(IA).The electrostatic interaction between CS and IA is weak and dynamic,so freeze-drying the solution of CS and IA enables the formation of continuous aerogel skeleton with self-healing ability and re-programmability;in comparison,the electrostatic interaction between CS and PA is strong and less dynamic,and thus mixing PA with CS in aqueous solution leads to fine precipitates of high flame retardancy due to the synergistic phosphorus-nitrogen effect.Integrating the continuous skeleton and the fine precipitates results in self-healing aerogles with UL-4 V-0 rating of flame retardancy aerogels and autoextinguishable feature.Interestingly,the aerogels after burning in flame for 30 s form a skin-core structure,and the carbonized skin protects the integrity of the aerogels and the self-healing ability of the internal parts.Therefore,this work provides a facile strategy to develop multifunctional aerogels which hold great promise for advanced applications.

关键词： Chitosan Flame retardancy Electrostatic interactions Biomass aerogel Self-healing

Distribution of oxide inclusions in H13 castings under super-gravity field with multi-stage rotation speeds

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Journal of Iron and Steel Research(International) 2024年第1期31卷 121-133页

作者： shao-ying Li Xiao-jun Xi Xing-ming Zhao Han-jie guo Jing guo School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing100083China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials Beijing100083China Beijing Beiye Functional Materials Corporation Beijing100192China Shandong Tianwu Forming Technology Co. Ltd.Liaocheng252024ShandongChina

The 42 kg industrial H13 castings were prepared by different super-gravity fields with multi-rotation speeds,and the distribution of oxide inclusions in the castings was studied.In addition,the inward movement Reynolds number and inward movement time of oxide inclusions as well as the solidification time of molten steel at different positions in the castings were calculated to clarify the removal mechanism of oxide inclusions in super-gravity field.The results show that the large size(i.e.,greater than 10μm)oxide inclusions are mainly concentrated in the inner and outer parts of the super-gravity castings with constant rotation speed(500 r min^(-1))and five-stage rotation speeds(500,600,750,850,and 950 r min^(-1)),respectively,while there are no large oxide inclusions in the super-gravity castings with three-stage rotation speeds(500,600,and 750 r min^(-1)).Although an increase in the particle size of inclusion and the rotation speed in super-gravity field is conducive to the increase in the inward movement Reynolds number of oxide inclusions and reduction in the inward movement time of oxide inclusions,it will reduce the local solidification time of molten steel.In the range of the rotation speed studied,the super-gravity field with three-stage rotation speeds has the best effect on the removal of inclusions in H13 molten steel.

关键词： Distribution Oxide inclusion H13 casting Super-gravity field Rotation speed

Crystalline-amorphous M@MNx（M=Co,Fe,Ni）encapsulated in nitrogen-doped carbon for enhanced efficient and durable hydrogen evolution reaction

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Rare Metals 2024年第4期43卷 1547-1556页

作者： Yang Yang Xiao-Chuan Duan shao-Hui guo Xian-Ming Zhang College of Materials Science and Engineering College of ChemistryKey Laboratory of Interface Science and Engineering in Advanced MaterialsTaiyuan University of Technology

Developing earth-abundant electrocatalysts for hydrogen evolution reaction（HER） is important for the sustainable energy economy.Herein,efficient and stable heterocatalysts consisting of crystalline-amorphous M@MNx（M=Co,Fe,Ni） encapsulated in N-doped carbon layers supported with N-doped graphene sheets（denoted as M@MNx@NC-NG） are synthesized by facile hydrothermal reaction and nitridation process.During the nitriding process,metal ions in M（tzbc）2（H2O）4(tzbc=4-（1H-1,2,4-triazol-1-yl） benzoic acid) complexes are reduced to crystalline M cores,accompanied by the formation of amorphous MNxshells;the tzbc ligands are insitu carbonized to form outermost N-doped carbon（NC）layers that connect with inner MNxvia M-N-C motifs inherited from the complex precursors and inhibit the transition of MNxfrom amorphous to crystalline phase.The Co@CoNx@NC-NG catalyst exhibits excellent HER activity with small overpotentials of 45 and 64 mV at a cathode current density of 10 mA·cm-2and low Tafel slopes of 40 and 85 mV·dec-1in 0.5 mol·L-1H2SO4and1.0 mol·L-1KOH electrolytes,respectively.The Co@CoNx@NC-NG retains 97% of the initial overpotential after 100,000 s in both acidic and alkaline media.Such outstanding HER performance originates from the crystalline-amorphous Co@CoNxthat redistributes electrons around the heterointerfaces,facilitating the conversion process of H+/H2O to hydrogen and thereby promoting HER kinetics.The outermost NC layers serve as the armor of Co@CoNx,and graphene nanosheets act as carriers of egg-like Co@CoNx@NC and conduction paths for electron shuttles,ensuring stable and continuous electrocatalytic hydrogen production.

关键词： Hydrogen evolution reaction Electrocatalysts Iron group metals Heterojunction Crystalline-amorphous structure

Synergistic effect of gradient Zn content and multiscale particles on the mechanical properties of Al-Zn-Mg-Cu alloys with coupling distribution of coarse-fine grains

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1392-1405页

作者： Liangliang Yuan Mingxing guo Yi Wang yun Wang Linzhong Zhuang Institute of Effectiveness Evaluation of Flying Vehicle Beijing 100085China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing 100083China

This study investigated the influence of graded Zn content on the evolution of precipitated and iron-rich phases and grain struc-ture of the alloys,designed and developed the Al–8.0Zn–1.5Mg–1.5Cu–0.2Fe(wt%)alloy with high strength and formability.With the increase of Zn content,forming the coupling distribution of multiscale precipitates and iron-rich phases with a reasonable matching ratio and dispersion distribution characteristics is easy.This phenomenon induces the formation of cell-like structures with alternate distribu-tion of coarse and fine grains,and the average plasticity–strain ratio(characterizing the formability)of the pre-aged alloy with a high strength is up to 0.708.Results reveal the evolution and influence mechanisms of multiscale second-phase particles and the corresponding high formability mechanism of the alloys.The developed coupling control process exhibits considerable potential,revealing remarkable improvements in the room temperature formability of high-strength Al–Zn–Mg–Cu alloys.

关键词： Al–Zn–Mg–Cu alloy iron-rich phase high formability microstructure mechanisms

Regeneration of the heart:f rom molecular mechanisms to clinical therapeutics

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Military Medical Research 2024年第1期11卷 80-97页

作者： Qian-yun guo Jia-Qi Yang Xun-Xun Feng Yu-Jie Zhou Beijing Key Laboratory of Precision Medicine of Coronary Atherosclerotic Disease Beijing Institute of Heart Lung and Blood Vessel DiseaseClinical Center for Coronary Heart DiseaseDepartment of CardiologyBeijing Anzhen HospitalCapital Medical UniversityBeijing 100029China

Heart injury such as myocardial infarction leads to cardiomyocyte loss,fibrotic tissue deposition,and scar formation.These changes reduce cardiac contractility,resulting in heart failure,which causes a huge public health burden.Military personnel,compared with civilians,is exposed to more stress,a risk factor for heart diseases,making cardiovascular health management and treatment innovation an important topic for military medicine.So far,medical intervention can slow down cardiovascular disease progression,but not yet induce heart regeneration.In the past decades,studies have focused on mechanisms underlying the regenerative capability of the heart and applicable approaches to reverse heart injury.Insights have emerged from studies in animal models and early clinical trials.Clinical interventions show the potential to reduce scar formation and enhance cardiomyocyte proliferation that counteracts the pathogenesis of heart disease.In this review,we discuss the signaling events controlling the regeneration of heart tissue and summarize current therapeutic approaches to promote heart regeneration after injury.

关键词： Heart regeneration Cardiac disease Therapeutics Signaling mechanisms

Hotspots and trends of risk factors in gastric cancer: A visualization and bibliometric analysis

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 2200-2218页

作者： Meng Li Ning Gao shao-Li Wang Yu-Feng guo Zhen Liu Department of Gastroenterology Guang'anmen HospitalChina Academy of Chinese Medical SciencesBeijing 100053China Department of Acupuncture and Moxibustion Guang'anmen HospitalChina Academy of Chinese Medical SciencesBeijing 100053China

BACKGROUND The lack of specific symptoms of gastric cancer(GC)causes great challenges in its early diagnosis.Thus it is essential to identify the risk factors for early diagnosis and treatment of GC and to improve the survival rates.AIM To assist physicians in identifying changes in the output of publications and research hotspots related to risk factors for GC,constructing a list of key risk factors,and providing a reference for early identification of patients at high risk for GC.METHODS Research articles on risk factors for GC were searched in the Web of Science core collection,and relevant information was extracted after screening.The literature was analyzed using Microsoft Excel 2019,CiteSpace V,and VOSviewer 1.6.18.RESULTS A total of 2514 papers from 72 countries and 2507 research institutions were retrieved.China(n=1061),National Cancer Center(n=138),and Shoichiro Tsugane(n=36)were the most productive country,institution,or author,respectively.The research hotspots in the study of risk factors for GC are summarized in four areas,namely:Helicobacter pylori(H.pylori)infection,single nucleotide polymorphism,bio-diagnostic markers,and GC risk prediction models.CONCLUSION In this study,we found that H.pylori infection is the most significant risk factor for GC;single-nucleotide polymorphism(SNP)is the most dominant genetic factor for GC;bio-diagnostic markers are the most promising diagnostic modality for GC.GC risk prediction models are the latest current research hotspot.We conclude that the most important risk factors for the development of GC are H.pylori infection,SNP,smoking,diet,and alcohol.

关键词： Gastric cancer Risk factor Bibliometric Research hotspots VOSviewer

An Intelligent Framework for Resilience Recovery of FANETs with Spatio-Temporal Aggregation and Multi-Head Attention Mechanism

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Computers, Materials & Continua 2024年第5期79卷 2375-2398页

作者： Zhijun guo yun Sun YingWang Chaoqi Fu Jilong Zhong Air Traffic Control and Navigation College Air Force Engineering UniversityXi’an710000China Institute of Systems Engineering Academy of Military ScienceBeijing100101China Equipment Management and UAV Engineering College Air Force Engineering UniversityXi’an710038China Defense Innovation Institute Academy of Military ScienceBeijing100071China

Due to the time-varying topology and possible disturbances in a conflict environment,it is still challenging to maintain the mission performance of flying Ad hoc networks(FANET),which limits the application of Unmanned Aerial Vehicle(UAV)swarms in harsh environments.This paper proposes an intelligent framework to quickly recover the cooperative coveragemission by aggregating the historical spatio-temporal network with the attention mechanism.The mission resilience metric is introduced in conjunction with connectivity and coverage status information to simplify the optimization model.A spatio-temporal node pooling method is proposed to ensure all node location features can be updated after destruction by capturing the temporal network structure.Combined with the corresponding Laplacian matrix as the hyperparameter,a recovery algorithm based on the multi-head attention graph network is designed to achieve rapid recovery.Simulation results showed that the proposed framework can facilitate rapid recovery of the connectivity and coverage more effectively compared to the existing studies.The results demonstrate that the average connectivity and coverage results is improved by 17.92%and 16.96%,respectively compared with the state-of-the-art model.Furthermore,by the ablation study,the contributions of each different improvement are compared.The proposed model can be used to support resilient network design for real-time mission execution.

关键词： Resilience cooperative mission FANET spatio-temporal node pooling multi-head attention graph network

Ileal collision tumor associated with gastrointestinal bleeding: A case report and review of literature

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World Journal of Gastrointestinal Surgery 2024年第2期16卷 628-634页

作者： Yu-Qi Wu Hong-Yan Wang Mu-Min shao Lin Xu Xiao-Yan Jiang shao-Ju guo Department of Gastroenterology Shenzhen Traditional Chinese Medicine HospitalThe Fourth Clinical Medical College of Guangzhou University of Chinese MedicineShenzhen 518033Guangdong ProvinceChina Department of Pathology Shenzhen Traditional Chinese Medicine HospitalThe Fourth Clinical Medical College of Guangzhou University of Chinese MedicineShenzhen 518033Guangdong ProvinceChina

BACKGROUND Collision tumors involving the small intestine,specifically the combination of a hamartomatous tumor and a lipoma,are extremely rare.To our knowledge,no previous case report has described a collision tumor composed of two benign tumors of different origins in the small intestine.CASE SUMMARY Here,we present the case of an 82-year-old woman who presented with hemorrhagic shock and was found to have a mass measuring approximately 50 mm×32 mm×30 mm in the terminal ileum.Based on computed tomography scan findings,the mass was initially suspected to be a lipoma.A subsequent colonoscopy revealed a pedunculated submucosal elevation consisting of two distinct parts with a visible demarcation line.A biopsy of the upper portion suggested a juvenile polyp(JP).Owing to the patient’s advanced age,multiple comorbidities,and poor surgical tolerance,a modified endoscopic submucosal dissection was performed.Histopathological examination of the excised mucosal mass revealed a lipoma at the base and a JP at the top,demonstrating evidence of rupture and associated bleeding.The patient’s overall health remained satisfactory,with no recurrence of hematochezia during the six-month follow-up period.CONCLUSION This case report provides new evidence for the understanding of gastrointestinal collision tumors,emphasizing their diverse clinical presentations and histopathological characteristics.It also offers diagnostic and therapeutic insights as well as an approach for managing benign collision tumors.

关键词： Collision tumor Gastrointestinal bleeding Hamartomatous tumor Lipoma Modified endoscopic submucosal dissection Case report