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Significant enhancement of crystallization kinetics of polylactide in its immiscible blends through an interfacial effect from comb-like grafted side chains

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Science China Chemistry 2016年第5期59卷 609-618页

作者： Yin Chen yaqiong zhang Feng Jiang JunyangWang Zhaohua Xu Zhigang Wang CAS Key Laboratory of Soft Matter Chemistry Hefei National Laboratory for Physical Sciences at the MicroscaleDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China Department of Material Technology Jiangmen PolytechnicJiangmen 529090China

A significant enhancement in isothermal crystallization kinetics of biodegradable polylactide(PLA) in its immiscible blends can be accomplished through blending it with a comb-like copolymer. PLA was blended with poly(ethylene glycol) methyl ether acrylate(PEGA) and poly[poly(ethylene glycol) methyl ether acrylate](PPEGA, a comb-like copolymer), respectively. The results measured from phase contrast optical microscopy(PCOM) and differential scanning calorimetry(DSC) indicate that PLA and PEGA components are miscible, whereas PLA and PPEGA components are immiscible. The study of crystallization kinetics for PLA/PEGA and PLA/PPEGA blends by means of polarized optical microscopy(POM) and DSC indicates that both PEGA and PPEGA significantly increase the PLA spherulitic growth rates, G, although PLA/PPEGA blends are immiscible and the glass transition temperatures of PLA only have slight decreases. PPEGA component enhances nucleation for PLA crystallization as compared with PEGA component owing to the heterogeneous nucleation effect of PPEGA at the low composition of 20 wt%, while PLA crystallization-induced phase separation for PLA/PEGA blend might cause further nucleation at the high composition of 50 wt%. DSC measurement further demonstrates that isothermal crystallization kinetics can be relatively more enhanced for PLA/PPEGA blends than for PLA/PEGA blends. The "abnormal" enhancement in G for PLA in its immiscible blends can be explained by local interfacial interactions through the densely grafted PEGA side chains in the comb-like PPEGA, even though the whole blend system(PLA/PPEGA blends) represents an immiscible one.

关键词： biodegradable polymer spherulite growth rate phase separation nucleation

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T cells promote the regeneration of neural precursor cells in the hippocampus of Alzheimer's disease mice

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Neural Regeneration Research 2014年第16期9卷 1541-1547页

作者： Jing Liu Yuxin Ma Sumin Tian Li zhang Mengmeng Zhao yaqiong zhang Dachuan Xu Department of Human Anatomy School of Basic Medical Sciences Southern Medical University Department of Human Anatomy School of Basic Courses Guangdong Pharmaceutical University

Alzheimer＇s disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present, the role of T cells in neuronal regeneration in the brain is unknown. We injected amyloid-beta 1-42 peptide into the hippocampus of six BALB/c wild-type mice and six BALB/c-nude mice with T-cell immunodeficiency to establish an animal model of Alzhei- mer＇s disease. A further six mice of each genotype were injected with same volume of normal saline. Immunohistochemistry revealed that the number of regenerated neural progenitor cells in the hippocampus of BALB/c wild-type mice was significantly higher than that in BALB/c-nude mice. Quantitative fluorescence PCR assay showed that the expression levels of peripheral T cell-associated cytokines （interleukin-2, interferon-y） and hippocampal microglia-related cyto- kines （interleukin-113, tumor necrosis factor-a） correlated with the number of regenerated neural progenitor cells in the hippocampus. These results indicate that T cells promote hippocampal neurogenesis in Alzheimer＇s disease and T-cell immunodeficiency restricts neuronal regeneration in the hippocampus. The mechanism underlying the promotion of neuronal regeneration by T cells is mediated by an increased expression of peripheral T cells and central microglial cytokines in Alzheimer＇s disease mice. Our findings provide an experimental basis for understanding the role of T cells in Alzheimer＇s disease.

关键词： nerve regeneration neurodegeneration Alzheimer's disease beta-amyloid 1-42 pep-tide neuronal precursors mice microglia interleukin-2 interferon-gamma interleukin-1β tumornecrosis factor-or microtubule associated protein NSFC grant neural regeneration

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Effect of mangrove restoration on crab burrow density in Luoyangjiang Estuary,China

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Forest Ecosystems 2015年第4期2卷 263-271页

作者： Wei Li Lijuan Cui Manyin zhang Yifei Wang yaqiong zhang Yinru Lei Xinsheng Zhao Beijing Key Laboratory of Wetland Services and Restoration Institute of Wetland ResearchChinese Academy of Forestry

Background： Mangrove restoration seeks to restore or rebuild degraded mangrove systems. The methods of mangrove restoration include ecological projects and restoration-oriented technologies, the latter of which are designed to restore the structure, processes as well as related physical, chemical and biological characteristics of wetlands and to ensure the provision of ecosystem services. As important components of mangrove ecosystem, benthic organisms and crabs play a key role in nutrient cycling. In addition, mangrove restoration, such as vegetation restoration measures, can lead to changes in the benthic faunal communities. This study investigates whether the presence of different mangrove species, age and canopy cover of mangrove communities affect the density of crab burrows. Methods： The Luoyangjiang Estuary, in the southeast of Fujian Province, was selected as our research area. A survey, covering 14 sites, was conducted to investigate the impacts of mangrove restoration on the density of crab burrows in four rehabilitated forests with different stand ages and canopy. Results： It was found that differences in vegetation types had a large impact on crab density and that the density of crab burrows was lower on exposed beaches （non-mangrove） than under mature Kondelio condel, Aegiceros corniculatum and Avicennio morina communities. In general, the amount of leaf litter and debris on mangrove mudfiats was greater than on the beaches as food sources for crabs. Two-factor analysis of variance （ANOVA） shows that changes in mangrove species and age since restoration had different effects on crab burrow density. The effect of canopy cover was highly significant on crab burrow density. Conclusions： The results suggest that in the process of mangrove restoration the combined effects of mangrove stand age, canopy cover and other factors should be taken into account. This study further supports the findings of the future scientific research and practice on mangrove resto

关键词： Canopy Crab burrow density Mangrove Restoration

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Exponentially increased nucleation ability for poly(L-lactide) by adding acid-oxidized multiwalled carbon nanotubes with reduced aspect ratios

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Science China Chemistry 2013年第2期56卷 181-194页

作者： ZHONG Yong zhang yaqiong YANG JingJing LI WenLin WANG ZhiGang XU DongHua CHEN ShouYu DING YunSheng CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and Engineering Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Institute of Polymer Materials & Chemical Engineering School of Chemical Engineering Hefei University of Technology Anhui Key Laboratory of Controllable Chemistry Reaction & Material Chemical Engineering

Acid-oxidized multiwalled carbon nanotubes (A-MWCNTs) with a range of reduced aspect ratios (from about 11 to 5.8) were obtained by acid oxidization of MWCNTs in the mixture of HNO 3 and H 2 SO 4 for varying periods of 1, 3, 8 and 12 h, respec- tively. The aspect ratios and surface functionalization of A-MWCNTs were well characterized by scanning electron microsco- py (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and thermogravimetric analysis (TGA). Poly(L-lactide)/A-MWCNT composites containing 0.5 wt% A-MWCNTs with a range of reduced aspect ratios were prepared by solution cast. The effects of added A-MWCNTs on the isothermal crystallization kinetics of poly(L-lactide)/A-MWCNT composites were investigated by means of differential scanning calorimetry (DSC), rheology and polarized optical microscopy (POM). It is surprising to find that not only the addition of A-MWCNTs effectively increases the poly(L-lactide) (PLA) crys- tallization kinetics, but also the nucleation ability of A-MWCNTs for PLA crystallization exponentially increases with the re- duced aspect ratio, that is to say, those with lower aspect ratios show much stronger nucleation ability for PLA crystallization than those with higher aspect ratios. The exponentially increased nucleation ability of A-MWCNTs with a range of reduced aspect ratios for PLA crystallization is disclosed.

关键词： poly(L-lactide) MWCNTs aspect ratio nucleation

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“十四五”时期公共图书馆促进数字包容路径探赜

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图书与情报 2022年第1期 118-123页

作者：张娅琼西北师范大学马克思主义学院甘肃兰州730070 甘肃政法大学文学与新闻传播学院甘肃兰州730070

数字社会建设、数字素养教育、智慧图书馆、公共文化服务均等化、网络使用安全等背景是引领公共图书馆在“十四五”时期促进数字包容的宏观视角。“十三五”时期,公共图书馆在顶层设计、完善数字基础设施、开展数字包容相关活动等方面... 详细信息

数字社会建设、数字素养教育、智慧图书馆、公共文化服务均等化、网络使用安全等背景是引领公共图书馆在“十四五”时期促进数字包容的宏观视角。“十三五”时期,公共图书馆在顶层设计、完善数字基础设施、开展数字包容相关活动等方面取得的成效,为公共图书馆“十四五”时期的数字包容实践提供了基础。“十四五”时期,公共图书馆促进数字包容的关键在于提升所有公民和不同群体公平获取信息和利用信息的能力,可以从完善数字基础设施,提升公民数字素养、打造多样化的数字包容活动,建设以人为中心的智慧图书馆、加强与政府及其他机构的合作三个方面积极发挥社会服务的作用。

关键词： “十四五”时期公共图书馆数字包容数字素养公共文化服务

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Fabrication of Ag@SiO2@Y2O3:Eu Core-shell Nanostructures and Their Metal Enhanced Fluorescence

Fabrication of Ag@SiO2@Y2O3:Eu Core-shell Nanostructures and...

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2013年（第五届）西部光子学学术会议

作者： yaqiong zhang Xuyin Tu Hairong Zheng College of Physics and Information Technology Shaanxi Normal University

A Silver nanocomposite which used to enhance the fluorescence was developed in this paper. Metal-enhanced fluorescence Y2O3 :Eu absorbed Ag@SiO2 compostie nanoparticles, where the silica-shell is used to control the distance between silver-core and Y2O3 :Eu. Silver nanoparticles with typical diameter of about 50nm have been prepared via a polyol process [1], and given high stability and mondispersity. Core-shell typed Ag@SiO 2 nanoparticles have also been prepared by depositing different thickness ranging from nm-30nm of silica on Ag nanoparticles through a modified Stober method [2]. The control where the silver core is removed by chemical etching was used as control samples to show the benefits of using silver nanoparticles[3]. Measurements of the luminescent emissions from the Ag@SiO2 nanoparticles, in comparison with control silica nanoparticles without silver cores, showed that the presence of the silver cores can increase the fluorescence intensity approximately. The fluorescence enhancement effects of the metal core size (silver nanoparticles) and the distance between the dye molecules and the metal core were systematically studied. The results showed that the fabricated nanostructure can effectively enhance the fluorescence signal. Potential applications of metal-induced photoluminescence enhancement range from sensing technologies to biomedical diagnostics[2].

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Surface enhanced fluorescence effect from Ag nanoparticles and Ag@SiO2 core-shell nanoparticles

Surface enhanced fluorescence effect from Ag nanoparticles a...

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第十七届全国光散射学术会议

作者： Yinxun Tu Hairong Zheng yaqiong zhang School of Physics and Information Technology Shaanxi Normal University

We prepared Ag nanoparticles by using high temperature solvothermal method and preparaed Ag@SiO core-shell nanoparticles through a modified St(o|¨)ber *** also studied the fluorescence enhancement effect of Rhodamine 6G affected by Ag nanoparticles and Ag@SiO which have different thickness of SiO using laser induced fluorescence *** show that 7.8-fold fluorescence enhancement factor of Rh6G molecules was *** the distance between noble metal nanoparticles and fluorescent molecule also play an important role in the fluorescence enhancement.

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Research and Design of Fractional-Order PID Controller for Inertial Stabilized Platform via Internal Model Control

Research and Design of Fractional-Order PID Controller for I...

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第40届中国控制会议

作者： yaqiong zhang Jiandu Guo Yi Liu Jing Zhou Yu Sun Information and Control Technology Department China North Vehicle Research Institute

Inertial stabilized platform（ISP） is an important part of inertial navigation system,and its mathematical model is established in this *** order to improve the accuracy and stability of the ISP,we propose a Fractional-Order PID（FOPID） controller design method based on internal model control（IMC） ***,a PID controller with only one parameter ? is constructed by the *** the FOPID controller is formed by adding integrator order λ and differentiator order μ.Finally,these three parameters are turned by gain crossover frequency,phase margin and gain robustness *** design technique proposed here is mathematically very ***,simulation results demonstrate that the proposed controller is better as compared to the classical PID controller.

关键词： Fractional-Order PID Internal model control Inertial stabilized platform

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酪蛋白酸钠衍生物对玉米醇溶蛋白纳米粒冻干复溶性和贮藏稳定性的影响

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中国食品学报 2018年第11期18卷 152-158页

作者：姚芳懿张亚琼俞良莉上海交通大学农业与生物学院上海200240 美国马里兰大学帕克分校营养与食品科学系美国马里兰20742

为了提高玉米醇溶蛋白(Zein)纳米粒的稳定性,选用两种酪蛋白酸钠衍生物——交联酪蛋白酸钠(CCA)和辛烷基-酪蛋白酸钠(OCA)作为稳定剂,分别制备CCA-Zein和OCA-Zein纳米粒,研究CCA/OCA的添加对Zein纳米粒冻干复溶性的影响,并对复溶后纳米... 详细信息

为了提高玉米醇溶蛋白(Zein)纳米粒的稳定性,选用两种酪蛋白酸钠衍生物——交联酪蛋白酸钠(CCA)和辛烷基-酪蛋白酸钠(OCA)作为稳定剂,分别制备CCA-Zein和OCA-Zein纳米粒,研究CCA/OCA的添加对Zein纳米粒冻干复溶性的影响,并对复溶后纳米粒热稳定性和在盐、糖溶液中的贮藏稳定性进行评价。通过测定纳米粒的平均粒径、粒径分布、zeta电位值和对纳米粒微观形态的观察,得到结论:CCA和OCA均能较好地稳定Zein纳米粒,使其在水、NaCl和蔗糖溶液中具有良好的复溶性;复溶后CCA-Zein/OCA-Zein纳米粒贮藏8周,其平均粒径、粒径分布和微观形貌均未发生明显改变,稳定性良好。另外,复溶于蔗糖溶液中纳米粒的平均粒径值与蔗糖溶液的浓度呈负相关性,即随着蔗糖溶液浓度的提高,纳米粒的平均粒径显著性减小。

关键词：玉米醇溶蛋白纳米粒酪蛋白酸钠衍生物冻干复溶性贮藏稳定性

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Ag@SiO2/LaF3:Eu3+ Composite Nanostructure and its Surface Enhanced Luminescence Effect

Ag@SiO2/LaF3:Eu3+ Composite Nanostructure and its Surface En...

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第十八届全国光散射学术会议

作者：郭静霞 Qingyan Han yaqiong zhang Zhaojin Wang Hairong Zheng School of Physics and Information Technology Shaanxi Normal University

＜正＞Ag@Si O2/La F3:Eu3+[1,2]core-shell nanostructure is fabricated through a wet chemical method in which the Si O2 layer functioned as a separation layer between Ag-core and La F3:Eu3+luminescence *** this system,t...

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