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Stable graphene oxide-based lyotropic liquid crystals for interfacial lubrication

Friction 2024年第5期12卷 954-967页

作者： yumei guo Hanglin LI Jiusheng LI Xiangqiong ZENG Laboratory for Advanced Lubricating Materials Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai201210China University of Chinese Academy of Sciences Beijing100049China

Lyotropic liquid crystals have lubricating properties due to their ordered assembly and fluidity,whose mesogens are often characterized by amphiphilic properties.Despite the attention that graphene oxide(GO)has been studied as a novel amphiphilic lyotropic mesogen this decade,and GO applied as a lubrication additive has been demonstrated in both oil and water-based systems,little research reveals the interfacial lubrication of GO liquid crystals yet.This work reports that GO aqueous dispersion can form lyotropic liquid crystals above a specific critical concentration of 5.00 mg/mL,providing a form of stable water-based lubricant,which can keep stable for several months and can reduce friction by 37.3%and wear by 25.24%.The liquid crystal phase was verified by polarizing microscope and synchrotron radiation small-angle X-ray scattering,and its rheological properties and viscoelasticity were studied by interfacial rheometer.The formation of lyotropic liquid crystals can enhance the stability of GO aqueous dispersions at high density,simultaneously ensuring friction decrease and anti-wear effect.It is attributed to the stable nematic network by the ordered GO sheets.The ordered assembly structure bears vertical shear force,therefore,reducing the wear.It is also assumed that the wide lateral size of graphene oxide promotes the nematic phase thus smoothes the graphene oxide film composed spontaneously under the coincidence of lamellar liquid crystal and 2D layered material.Through this work,the interlayer lubrication of GO was optimized,and the problem of GO dispersion sedimentation was solved by self-assembly.The range of interfacial lubrication of GO aqueous dispersion has been expanded and the synergistic effect is conducive to the environmentally friendly lubricants.

关键词： lyotropic liquid crystal graphene oxide aqueous lubrication tribological behavior

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Application and Evaluation of Continuous Care Model Based on the Omaha System in Stroke Patients after Discharge

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Medicinal Plant 2024年第1期15卷 79-81,84页

作者： Jia LI yumei guo Xiaochun LI Department of Nursing Affiliated Hospital of Jinggangshan UniversityJi'an 343100China

[Objectives]To explore the effect of continuous nursing model based on the Omaha system on stroke patients.[Methods]A total of 40 stroke patients in the inpatient department of the Rehabilitation Department of Affiliated Hospital of Jinggangshan University were selected and divided into two groups by the random number table method.Patients in the control group were given routine nursing,and those of the observation group were given continuous nursing based on the Omaha system theory.The score of neurological impairment,daily living ability scale and the quality of life,as well as patients satisfaction rate before and after treatment were compared between the two groups.[Results]The score of neurological impairment,daily living activity ability and the quality of life,as well as patients nursing satisfaction rate in the observation group were significantly better than those of the control group,with statistical significance(P<0.05).[Conclusions]The continuous nursing model based on the Omaha system can significantly improve the neurological function of stroke patients,improve their quality of life and life ability,and promote their rehabilitation.

关键词： Omaha system Continuous nursing Stroke

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Formulation of lyotropic liquid crystal emulsion based on natural sucrose ester and its tribological behavior as novel lubricant

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Friction 2022年第11期10卷 1879-1892页

作者： yumei guo Jiusheng LI Xiaojie ZHOU Yuzhao TANG Xiangqiong ZENG Laboratory for Advanced Lubricating Materials Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China University of Chinese Academy of Sciences Beijing 100049China National Facility for Protein Science in Shanghai Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China

The tribological behavior of oil-in-water emulsions formulated with natural lyotropic liquid crystal(LLC)emulsifiers based on natural sucrose ester was studied for the first time.Polarized optical microscopy,synchrotron radiation small-angle X-ray scattering,wide-angle X-ray scattering,and synchrotron radiation infrared microspectroscopy demonstrated that LLC emulsifiers were tightly ordered at the oil–water interface with a distinct nematic texture.The viscosity of emulsion was observed to change over time.Moreover,the zeta potential and laser particle size distribution verified the emulsion’s satisfactory stability.The frictional shearing test proved that the coefficient of friction of the emulsion versus pure oil decreased by 34.2%.The coefficient of friction of the emulsion with liquid crystal decreased 10.1%versus that without liquid crystal.Although liquid crystal emulsion did not exhibit outstanding anti-wear performance compared with pure oil,its wear volume was 29.4%less than the emulsion without liquid crystal.X-ray photoelectron spectroscopy and scanning electron microscope–energy dispersive X-ray spectroscopy(SEM–EDS)proved that the tribo-film of the emulsion with liquid crystal was formed synergistically by the liquid crystal phase with the base oil.The formulation affecting the lubricant quality was further studied by orthogonal experiments.The resulting Stribeck curve behavior suggested that proper composition with a slightly higher viscosity can better reduce friction in both boundary lubrication and mixed lubrication regimes.The lubrication mechanism indicated that the periodically ordered liquid crystal was transported to the sliding asperity in the form of emulsion droplets,which bored the pressure and released the oil to form a tribo-film.This LLC emulsion is environmentally friendly and potentially non-irritant to the skin.Thus,it has promising application prospects as novel water-based and biological lubricants.

关键词： lyotropic liquid crystal(LLC) emulsion aqueous lubrication tribological behavior

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Optical transmitter module with hybrid integration of DFB laser diode and proton-exchanged LiNbO_(3)modulator chip

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Journal of Semiconductors 2022年第6期43卷 34-39页

作者： Xuyang Wang He Jia Junhui Li yumei guo Yu Liu State Key Laboratory on Integrated Optoelectronics Institution of SemiconductorsChinese Academy of SciencesBeijing 100083China University of Chinese Academy of Sciences Beijing 100049China Beijing Shiweitong Science&Technology Co. Ltd.Beijing 100176China

In this work,a hybrid integrated optical transmitter module was designed and fabricated.A proton-exchanged Mach–Zehnder lithium niobate(LiNbO_(3))modulator chip was chosen to enhance the output extinction ratio.A fiber was used to adjust the rotation of the polarization direction caused by the optical isolator.The whole optical path structure,including the laser chip,lens,fiber,and modulator chip,was simulated to achieve high optical output efficiency.After a series of process improvements,a module with an output extinction ratio of 34 dB and a bandwidth of 20.5 GHz(from 2 GHz)was obtained.The optical output efficiency of the whole module reached approximately 21%.The link performance of the module was also measured.

关键词： optical transmitter module hybrid integration DFB laser chip LiNbO3 modulator chip

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Water lubrication of graphene oxide-based materials

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Friction 2022年第7期10卷 977-1004页

作者： Shaoqing XUE Hanglin LI yumei guo Baohua ZHANG Jiusheng LI Xiangqiong ZENG Laboratory for Advanced Lubricating Materials Shanghai Advanced Research InstituteChinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghai 201210China School of Environmental and Chemical Engineering Shanghai UniversityShanghai 200444China Key Laboratory for Advanced Materials School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Water is as an economic,eco-friendly,and efficient lubricant that has gained widespread attention for manufacturing.Using graphene oxide(GO)-based materials can improve the lubricant efficacy of water lubrication due to their outstanding mechanical properties,water dispersibility,and broad application scenarios.In this review,we offer a brief introduction about the background of water lubrication and GO.Subsequently,the synthesis,structure,and lubrication theory of GO are analyzed.Particular attention is focused on the relationship between pH,concentration,and lubrication efficacy when discussing the tribology behaviors of pristine GO.By compounding or reacting GO with various modifiers,amounts of GO-composites are synthesized and applied as lubricant additives or into frictional pairs for different usage scenarios.These various strategies of GO-composite generate interesting effects on the tribology behaviors.Several application cases of GO-based materials are described in water lubrication,including metal processing and bio-lubrication.The advantages and drawbacks of GO-composites are then discussed.The development of GO-based materials for water lubrication is described including some challenges.

关键词： tribology water lubrication graphene oxide(GO)

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不确定性会影响央行沟通效果吗

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财贸经济 2024年第6期45卷 88-104页

作者：郭豫媚郭俊杰中央财经大学金融学院 102206

在复杂的国内外经济形势下,通过央行沟通引导预期对稳定经济变得越发关键。本文通过构建包含经济不确定性和央行沟通在内的理论模型,分析了央行沟通如何通过信息机制起作用,并探讨了经济不确定性可能产生的影响。理论模型分析表明,央行... 详细信息

在复杂的国内外经济形势下,通过央行沟通引导预期对稳定经济变得越发关键。本文通过构建包含经济不确定性和央行沟通在内的理论模型,分析了央行沟通如何通过信息机制起作用,并探讨了经济不确定性可能产生的影响。理论模型分析表明,央行沟通通过信息机制能够降低市场波动,但是经济不确定性会对央行沟通的信息机制产生削弱作用。本文以中国人民银行发布的《中国货币政策执行报告》为沟通样本进行了实证分析,回归结果表明中国人民银行的沟通能够通过信息机制降低金融市场波动,但经济不确定性会抵消上述影响。在此基础上,本文将基准模型拓展到汇率市场,探讨了人民币汇率改革对信息机制的影响,并通过“8·11”汇改进一步在实证层面证实了央行沟通能够通过信息机制发挥作用。本文是对央行沟通理论机制研究的重要补充,不仅从经济不确定性视角为已有研究的分歧提供了一种解释,而且对改善央行沟通的政策效果、提高央行沟通引导预期的能力具有重要意义。

关键词：央行沟通信息机制文本相似度不确定性

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极简主义设计美学思想在景观设计中的运用探究

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艺术科技 2024年第1期37卷 236-238页

作者：郭玉妹南京林业大学艺术设计学院江苏南京210037

目的:极简主义强调“物即是本身”,旨在摒除过多的复杂因素,将设计的艺术价值集中体现在人与物、人与生活环境以及人与人之间的和谐关系中,因此设计师采用一种极简的设计方法,更好地体现这种和谐。方法:文章通过查找文献,了解极简主义美... 详细信息

目的:极简主义强调“物即是本身”,旨在摒除过多的复杂因素,将设计的艺术价值集中体现在人与物、人与生活环境以及人与人之间的和谐关系中,因此设计师采用一种极简的设计方法,更好地体现这种和谐。方法:文章通过查找文献,了解极简主义美学,分析极简主义景观设计案例,从而使景观设计更符合现代审美。结果:景观绿化是体现一座城市内涵的物质文化载体,但随着城市化进程的加快,城市景观变得烦琐且浮夸,存在形式化现象,缺少真正的审美与功能。因此要使景观简约化,提高审美价值,彰显其使用功能。结论:作为极简主义景观设计大师,彼得·沃克将欧洲极简主义几何美学原则与传统景观美学设计艺术手法深度结合,打造了许多既有形式美、又有韵律美的现代景观,满足了当代人的审美需求和空间需求,将极简主义美学运用到极致。

关键词：极简主义艺术设计美学景观设计彼得·沃克

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A strategy for mechanically integrating robust hydrogeltissue hybrid to promote the anti-calcification and endothelialization of bioprosthetic heart valve

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Regenerative Biomaterials 2024年第2期3卷 123-136页

作者： Haoshuang Wu Nuoya Chen Tiantian Zheng Li Li Mengyue Hu yumei Qin Gaoyang guo Li Yang Yunbing Wang National Engineering Research Center for Biomaterials Sichuan UniversityChengdu 610065China Institute of Clinical Pathology West China Hospital of Sichuan UniversityChengdu 610041China College of Polymer Science and Engineering Sichuan UniversityChengdu 610065China

Bioprosthetic heart valve(BHV)replacement has been the predo-minant treatment for severe heart valve diseases over decades.Most clinically available BHVs are crosslinked by glutaraldehyde(GLUT),while the high toxicity of residual GLUT could initiate calcification,severe thrombosis,and delayed endothelializa-tion.Here,we construed a mechanically integrating robust hydrogel-tissue hybrid to improve the performance of BHVs.In particular,recombinant humanized coilagen type Ⅲ(rhCOLⅢ),which was precisely customized with anti-coagulant and pro-endothelialization bioactivity,was first incorporated into the polyvinyl alcohol(PVA)-based hydrogel via hydrogen bond interactions.Then,tannic acid was introduced to enhance the mechanicalperfo of PVA-based hvdrogel and interfacial bonding between the hydrogel layer and bio-derived tissue due to the strong affinity for a wide range of substrates.In vitro and in vivo experimental results confirmed that the GLUT-crosslinked BHVs modified by the robust PVA-based hydrogel embedded rhCOLII and TA possessed long-term anti-coagulant,accelerated endothelialization,mild inflammatory response and anti-calcification properties.Therefore,our mechanically integrating robust hydrogel-tissue hybrid strategy showed the potential to enhance the service function and prolong the service life of the BHVs after implantation.

关键词： bioprosthetic heart valves recombinant humanized collagen typeⅢ endothelialization anti-calcification anti-coagulation

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Moxibustion of Zusanli(ST36)and Shenshu(BL23)alleviates the inflammation of rheumatoid arthritis in rats through regulating macrophage migration inhibitory factor/glucocorticoids signaling

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Journal of Traditional Chinese Medicine 2024年第2期44卷 353-361页

作者： ZHANG Linlin ZHONG yumei LU Wenting SHANG Yanan guo Yanding LUO Xiaochao CHEN Yang LUO Kun HU Danhui YU Huiling ZHOU Haiyan Acupuncture and Moxibustion College Chengdu University of Traditional Chinese MedicineChengdu 610075China Department of Painology First People's Hospital of ChengduChengdu 610095China Chinese Evidence-Based Medicine Centre West China HospitalSichuan UniversityChengdu 610044China Traditional Chinese Medicine College Chongqing Medical UniversityChongqing 400016China External treatment center First People's Hospital of ChengduChengdu 610095China

OBJECTIVE:To test the hypothesis that moxibustion may inhibit rheumatoid arthritis(RA)synovial inflammation by regulating the expression of macrophage migration inhibitory factor(MIF)/glucocorticoids(GCs).METHODS:Fifty male Sprague-Dawley rats were randomly divided into five groups(n=10 each):blank Control(CON)group,RA Model(RA)group,Moxibustion(MOX)group,MIF inhibitor(S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester(ISO-1)group,and Moxibustion+MIF inhibitor ISO-1(MOX+ISO-1)group.Rats in the ISO-1 group and ISO-1+MOX group were intraperitoneally injected with the inhibitor ISO-1.The rats in the RA group,ISO-1 group,MOX group,and ISO-1+MOX group were injected with Freund's complete adjuvant(FCA)in the right hind footpad to establish an experimental RA rat model.In the MOX group and MOX+ISO-1 group,rats were treated with Moxa.The thickness of the footpads of the rats in each group was measured at three-time points before,after modeling and after moxibustion treatment.The contents of serum MIF,corticosterone(CORT),tumor necrosis factor-α(TNF-α)and interleukin-1β(IL-1β)were detected by enzyme-linked immunosorbent assay;and the contents of synovial MIF were detected by Western blot.Hematoxylin-eosin(HE)staining method was used to observe the pathological changes of synovial tissue under a section light microscope,and pathological scoring was performed according to the grading standard of the degree of synovial tissue disease.RESULTS:Moxibustion was found to reduce the level of MIF and alleviate inflammation in RA rats in this study.In addition,after inhibiting the expression of MIF,the level of CORT increased,and the level of TNF-α decreased.Treating RA rats with inhibited MIF by moxibustion,the level of CORT was almost unchanged,but the level of TNF-α further decreased.The correlation analysis data suggested that MIF was positively related to the expression of TNF-α and negatively correlated with the expression of CORT.CONCLUSION:Reducing MIF to increase CORT and decrease TNF-α by moxibustion

关键词： rheumatoid arthritis macrophage migration inhibitory factor moxibustion corticosterone glucocorticoids

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货币政策预期测度与央行预期管理效果评估

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金融评论 2023年第6期15卷 47-71,123页

作者：郭豫媚王航郭俊杰中央财经大学金融学院

宏观经济政策效果评估是健全宏观经济治理体系的重要一环。然而,预期管理作为中央银行引导预期的重要宏观调控手段,其效果评估面临着缺少关键指标等问题,仍有较大的完善空间。本文基于宏观经济研究报告文本,采用词典法从立场和情绪两个... 详细信息

宏观经济政策效果评估是健全宏观经济治理体系的重要一环。然而,预期管理作为中央银行引导预期的重要宏观调控手段,其效果评估面临着缺少关键指标等问题,仍有较大的完善空间。本文基于宏观经济研究报告文本,采用词典法从立场和情绪两个维度构造市场的货币政策预期,并在此基础上评估预期管理的效果。实证研究表明,中央银行预期管理能够对市场货币政策立场和情绪产生显著的正向影响,其中对市场货币政策立场的影响具有显著的持续性,验证了我国预期管理的有效性。进一步分析表明,预期管理效果在不同的经济政策不确定性、货币政策倾向、货币政策预期和宏观分析师预测误差等情况下均存在显著的异质性,在市场信息需求较高的情况下预期管理能发挥更大的作用。本文研究为预期管理政策效果评估和相关学术研究提供了重要的基础性指标,研究结果对于提高央行沟通有效性和完善央行预期管理政策框架具有重要启示。

关键词：预期管理市场预期政策评价央行沟通

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