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Distribution pattern of acoustic and streaming field during multi-source ultrasonic melt treatment process

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China Foundry 2023年第5期20卷 452-460页

作者： Xiao-gang Fang Qi Wei Tian-yang Zhang ji-guang liu You-wen Yang Shu-lin Lü Shu-sen Wu Yi-qing Chen School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Engineering Research Center of High-Performance Copper Alloy Materials and Processing Ministry of EducationHefei 230009China State Key Laboratory of Material Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

The ultrasonic melt treatment(UMT)is widely used in the fields of casting and ***,there are certain drawbacks associated with the conventional process of single-source ultrasonic(SSU)treatment,such as the fast attenuation of energy and limited range of *** this study,the propagation models of SSU and four-source ultrasonic(FSU)in Al melt were respectively established,and the distribution patterns of acoustic and streaming field during the ultrasonic treatment process were investigated by numerical simulation and physical *** simulated results show that the effective cavitation zone is mainly located in a small spherical region surrounding the end of ultrasonic horn during the SSU treatment *** the FSU is applied,the effective cavitation zone is obviously expanded in the *** increases at first and then decreases with increasing the vibration-source spacing(Lv)from 30 mm to 100 ***,when the Lv is 80 mm,the area of effective cavitation zone reaches the largest,indicating the best effect of ***,the acoustic streaming level and flow pattern in the melt also change with the increase of *** the Lv is 80 mm,both the average flow rate and maximum flow rate of the melt reach the highest,and the flow structure is more stable and uniform,with the typical morphological characteristics of angular vortex,thus significantly expanding the range of acoustic *** accuracy of the simulation results was verified by physical experiments of glycerol aqueous solution and tracer particles.

关键词： four-source ultrasound acoustic cavitation streaming field vibration-source spacing

Numerical simulation and optimization of shell mould casting process for leaf spring bracket

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China Foundry 2020年第1期17卷 35-41页

作者： ji-guang liu Lei Yang Xiao-gang Fang Bin Li You-wen Yang Li-zhi Fang Zheng-bing Hu School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Hefei South Automobile Component Co.Ltd. Hefei 231200China

Although the shell mould casting process has a wide range of application in many fields,the prediction of casting defects is still a *** the present work,a typical leaf spring bracket casting of ZG310-570 was fabricated by shell mold *** finite element model and ProCAST software were utilized for simulating the filling and solidification processes of the casting;and the formation mechanism of the gas pore,and shrinkage porosity defects were *** results indicate that the gas pore and shrinkage porosity defects are formed due to air entrapment,insufficient feeding and non-sequential ***,through changing the position of risers,adding a connecting channel between the risers,and setting blind risers at the U-shaped brackets,an optimized gating and feeding system was established to improve the quality of the *** optimization,the gas pore and shrinkage porosity defects of the leaf spring bracket casting are effectively *** experiment results with the optimized casting process are in good agreement with the numerical simulation,which verifies the validity of the finite element model in the shell mould casting.

关键词： shell mould casting numerical simulation leaf spring bracket process optimization

Microstructure evolution and mechanical properties of Mg-12Zn-2Y alloy containing quasicrystal phase fabricated by different casting processes

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China Foundry 2021年第2期18卷 147-154页

作者： ji-guang liu Bu-ke Dong Xiao-gang Fang Bin Li You-wen Yang Tian-yu Wu Rui-dong Ren Shu-sen Wu School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China State Key Lab of Materials Processing ami Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

Although icosahedral quasicrystal phase(denoted as I-phase)has been verified as an outstanding reinforcing phase,the mechanical properties of quasicrystal-reinforced Mg-Zn-Y alloys fabricated by traditional casting processes are still unsatisfactory due to the serious segregation of intermetallic *** this study,the microstructure and mechanical properties of Mg-12Zn-2Y alloy fabricated by different casting processes,including permanent mold casting,squeeze casting and rheo-squeeze casting with ultrasonic vibration,were systematically investigated and *** results show that massive,large-sized I-phase and Mg7Zn3 phase gather together in the permanent mold cast sample,while the squeeze casting process leads to the transformation of I-phase into fine lamellar morphology and the amount of Mg7Zn3 *** to the rheo-squeeze casting process,when the ultrasonic vibration is exerted with power from 800 W to 1,600 W,theα-Mg grains are refined and spheroidized to a large extent,and the lamellar spacing of the eutectic structure is significantly reduced,accompanied by some tiny granular I-phase scattering in theα-Mg ***,when the ultrasonic power continuously increases to 2,400 W,the eutectic structure becomes *** best mechanical properties of the rheo-squeeze cast alloy are obtained when the ultrasonic power is 1,600 *** microhardness,yield strength,ultimate tensile strength and elongation are 79.9 HV,140 MPa,236 MPa,and 3.25%,which are 44.1%,26.1%,25.5%,132.1%respectively higher than the corresponding values of the squeeze casting sample,and are 47.6%,44.3%,69.8%,and 253.3%respectively higher than the corresponding values of the permanent mold casting sample.

关键词： Mg-Zn-Y alloy quasicrystal rheo-squeeze casting ultrasonic vibration treatment

具有温敏导电多重响应的智能磁性颗粒制备及性能

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高分子学报 2019年第7期50卷 695-701页

作者：刘佳威张强刘继广北京服装学院材料科学与工程学院

通过两步自由基聚合制备了PANI/P(St-NIPAM)/Fe3O4温敏导电磁性复合颗粒并研究了其导电性能.首先以改性四氧化三铁(Fe3O4)、苯乙烯(St)和N-异丙基丙烯酰胺(NIPAM)共聚制备出P(St-NIPAM)/Fe3O4颗粒,然后进行苯胺吸附与氧化聚合制备出PANI... 详细信息

通过两步自由基聚合制备了PANI/P(St-NIPAM)/Fe3O4温敏导电磁性复合颗粒并研究了其导电性能.首先以改性四氧化三铁(Fe3O4)、苯乙烯(St)和N-异丙基丙烯酰胺(NIPAM)共聚制备出P(St-NIPAM)/Fe3O4颗粒,然后进行苯胺吸附与氧化聚合制备出PANI/P(St-NIPAM)/Fe3O4导电复合颗粒.用扫描电镜(SEM)、热重分析(TG)和红外(IR)等测试表征颗粒,结果表明复合颗粒具有核壳结构,聚苯胺在颗粒中的含量依赖于NIPAM的投料比.动态光散射(DLS)结果表明颗粒尺寸对温度具有响应性,复合颗粒同时拥有磁性和导电性.复合颗粒的电导率研究表明颗粒的导电性可以通过组成调控,在恒定单体投料比的情况下,随着颗粒中聚合物与Fe3O4重量比从1:1增加到10:1,颗粒溶液25°C时的电导率从58.4μS/cm上升到860μS/cm;在恒定单体总量与磁性颗粒重量比为10:1的情况下,随着NIPAM/St比例从2 mol%增加到10 mol%,颗粒溶液电导率从698μS/cm增加到1120μS/cm.与25°C的样品相比,在50°C下颗粒溶液的电导率均明显下降,显示出明显的温度响应性;这种性能对发展温度响应的智能电子材料具有重要意义.

关键词：温度响应导电性磁性颗粒智能颗粒聚苯胺

Unraveling brain aging through the lens of oral microbiota

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Neural Regeneration Research 2025年第7期20卷 1930-1943页

作者： Qinchao Hu Si Wang Weiqi Zhang jing Qu guang-Hui liu State Key Laboratory of Membrane Biology Institute of ZoologyChinese Academy of SciencesBeijingChina Hospital of Stomatology Guanghua School of StomatologyGuangdong Provincial Key Laboratory of StomatologySun Yat-sen UniversityGuangzhouGuangdong ProvinceChina Advanced Innovation Center for Human Brain Protection and National Clinical Research Center for Geriatric Disorders Xuanwu HospitalCapital Medical UniversityBeijingChina Aging Translational Medicine Center International Center for Aging and CancerBeijing Municipal Geriatric Medical Research CenterXuanwu HospitalCapital Medical UniversityBeijingChina CAS Key Laboratory of Genomic and Precision Medicine Beijing Institute of GenomicsChinese Academy of Sciences and China National Center for BioinformationBeijingChina University of Chinese Academy of Sciences BeijingChina Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijingChina Aging Biomarker Consortium BeijingChina State Key Laboratory of Stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of SciencesBeijingChina Beijing Institute for Stem Cell and Regenerative Medicine BeijingChina

The oral cavity is a complex physiological community encompassing a wide range of *** of oral microbiota can lead to various oral infectious diseases,such as periodontitis and tooth decay,and even affect systemic health,including brain aging and neurodegenerative *** studies have highlighted how oral microbes might be involved in brain aging and neurodegeneration,indicating potential avenues for intervention *** this review,we summarize clinical evidence demonstrating a link between oral microbes/oral infectious diseases and brain aging/neurodegenerative diseases,and dissect potential mechanisms by which oral microbes contribute to brain aging and *** also highlight advances in therapeutic development grounded in the realm of oral microbes,with the goal of advancing brain health and promoting healthy aging.

关键词： Alzheimer's disease brain aging multiple sclerosis neurodegeneration neurodegenerative diseases oral microbiota Parkinson's disease periodontitis bacteria Porphyromonas gingivalis

Preparation and Performance of Ternary Early Strength Agent and Quercetin Composite Cement Sealing Material

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 130-140页

作者： liu jian CHEN Meiting ji Xiaoli XU Chao WANG Chunmei Department of Safety Science and Engineering Anhui University of Science and TechnologyHuainan 232001China Key Laboratory of Mine Safety and High Efficient Mining Jointly Built by Province and Education Ministry Anhui University of Science and TechnologyHuainan 232001China Department of Chemical Engineering and Explosives Anhui University of Science and TechnologyHuainan 232001China

A ternary early-strengthening agent consisting of calcium formate+triethanolamine+lithium sulfate was compounded with quercetin to shorten the setting time of cementitious materials while ensuring their early *** optimum ratio of the three early-strengthening agents was determined as 0.5%calcium formate+0.04%triethanolamine+0.4%lithium sulfate by response surface *** effects of the ternary early-strengthening agent composed of calcium formate+triethanolamine(TEA)+lithium sulfate on cementitious pore sealing materials under the synergistic effect of quercetin were studied by means of the performance tests of compressive strength,fluidity,and setting time,and the microstructural characterizations of X-ray powder diffractometer(XRD),thermogravimetry(TG-DSC)and scanning electron microscopy(SEM).The study shows that the synergistic effect of ternary early-strengthening agent and quercetin forms a multi-performance composite admixture for cementitious *** best performance was obtained with the compounding scheme of 0.5%calcium formate+0.04%triethanolamine+0.4%lithium sulfate ternary early-strengthening agent and 0.05%*** compressive strength of 1,3,7,and 28 d are 94.8%,39.8%,42%,and 28%higher than those of the blank group,*** initial time and final setting time are 41 and 57 minutes,*** to the microscopic analysis,the network and fibrous C-S-H gels generated by ternary early-strengthening agents are attached to the surface promoted by quercetin,which forms skeleton support while thickening and solidifying the cement slurry,which enhances the early compressive strength of the cement-based materials.

关键词： sealing material ternary early-strengthening agent quercetin synergetic effect response surface methodology

透明聚酰胺聚集态结构与拉伸性能的热处理效应

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高分子学报 2019年第2期50卷 189-198,I0005页

作者：董思远朱平刘继广王笃金董侠北京服装学院材料科学与工程学院北京100029 中国科学院化学研究所中国科学院工程塑料重点实验室北京分子科学国家研究中心北京100190

研究了透明聚酰胺PAPACM12和PAMACM12的基本性能以及热处理对透明聚酰胺聚集态结构和应力应变行为的影响,着重分析并对比了重复单元结构相近的透明聚酰胺在聚集态结构上的差别.示差扫描量热法(DSC)的结果表明,PAPACM12的玻璃化转变温度... 详细信息

研究了透明聚酰胺PAPACM12和PAMACM12的基本性能以及热处理对透明聚酰胺聚集态结构和应力应变行为的影响,着重分析并对比了重复单元结构相近的透明聚酰胺在聚集态结构上的差别.示差扫描量热法(DSC)的结果表明,PAPACM12的玻璃化转变温度为135.6°C、熔点为244.6°C,PAMACM12的玻璃化转变温度为160°C.对比傅里叶变换红外光谱(FTIR)谱图的结果,PAPACM12在对应了酰胺基团变形振动的961 cm^(-1)结晶谱带与PAMACM12有明显差异.经过退火处理后,PAPACM12在一维广角X射线衍射(WAXD)曲线上出现了2个衍射峰,其晶面间距分别为0.50和0.45 nm,对应于聚酰胺的α晶型,这是冷结晶所致;PAMACM12经过热处理后仍为无定形状态.退火后处理后PAPACM12的拉伸强度得到了改善、断裂强度下降,这也是冷结晶过程中微晶含量不断增加所致,而PAMACM12的拉伸强度和断裂强度均有所下降.

关键词：透明聚酰胺热处理聚集态结构拉伸性能

线性脂环族聚酰胺化学结构对其力学和光学性能的影响

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高分子学报 2021年第3期52卷 297-303页

作者：周臣旭董思远朱平刘继广董侠王笃金中国科学院化学研究所中国科学院工程塑料重点实验室北京分子科学国家实验室北京100190 中国科学院大学北京100049 北京服装学院材料科学与工程学院北京100029

以重复单元结构不同的3种线性脂环族聚酰胺(LATPA)材料为研究对象,通过核磁共振谱、红外光谱、热分析、X射线衍射等技术,研究了链结构单元的侧基、端基对材料聚集态结构的影响,并对比研究了不同聚集态结构材料的宏观力学性能和光学透明... 详细信息

以重复单元结构不同的3种线性脂环族聚酰胺(LATPA)材料为研究对象,通过核磁共振谱、红外光谱、热分析、X射线衍射等技术,研究了链结构单元的侧基、端基对材料聚集态结构的影响,并对比研究了不同聚集态结构材料的宏观力学性能和光学透明性差异,建立了链结构、聚集态结构与力学性能、光学性能的关系.研究发现,侧基带来的大空间位阻降低了LATPA的结晶度,提高了材料的玻璃化转变温度;较长的柔性端基分子链有助于高分子链的有序规整排列,可生成尺寸很小的微晶;聚集态结构直接影响材料的力学和光学性能,无定形LATPA和含有微晶结构的LATPA都具有良好的光学透明性,前者的透明性更高,后者的综合力学性能更好.

关键词：线性脂环族聚酰胺链结构聚集态结构力学性能光学透明性

Manufacture the conducting polymer with light

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Science China Chemistry 2025年第01期 8-9页

作者： Yang Li Tianyu Li Yan ji Baoguang liu College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology) Nanjing University of Posts & Telecommunications

Poly(3,4-ethylenedioxythiophene) (PEDOT), heralded as the “king” of conducting polymers, is esteemed in bioelectronics for its mixed electronic and ionic conductivity, mechanical properties compatible with biological tissues, tunable healing ability and stability in diverse environments [1]. Based on additive manufacturing of three-dimensional structures,PEDOT realizes the implementation in the efficient production of flexible bioelectronics, the construction of intricate electrode-neural implantations, and the development of smart brain-computer-interfaces [2].

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