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Gelation of polymeric nanoparticles

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Particuology 2014年第3期12卷 1-11页

作者： Hua Wu Massimo Morbidelli Institute for Chemical and Bioengineering.Department of Chemistry and Applied Biosciences ETH Zurich8093 ZurichSwitzerland

We review how, starting from polymeric nanoparticles, to generate clusters of fractal morphology and to expand the entire space and interconnect to form gels, through either Brownian motion or intense shear-induced aggregation. In the case of Brownian motion-induced gelation, specific techniques developed to obtain uniform structure of gels under both reaction-limited and diffusion-limited cluster aggregation conditions have been described. In the case of intense shear-induced gelation as a newly developed technique, our focus is on its principle, theoretical development and advantages with respect to Brownian motion-induced gelation in practical applications. We consider gelation of both rigid and soft particles. As a physical process, the bonding between the particles within gels is owed to van der Waals attractions, thus being easily broken. However, in the case of soft particles that can coalesce upon contact, the coalescence can allow the particles to stick together forming permanent gels. In this case, the gel structure can be controlled by controlling the degree of coalescence. Techniques used to control the degree of coalescence have also been described.

关键词： Structured material Fractal Gelation Gel Polymer

PREPARATION AND PROPERTIES OF ETHYL-CYANOETHYL CELLULOSE/POLYACRYLIC ACID COMPOSITE FILMS WITH REFLECTION COLORS

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Chinese Journal of Polymer Science 2001年第3期19卷 277-282页

作者： Yong Huang Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 China Laboratory of Cellulose and Lignocellulosics Chemistry Guangzhou Institute of Chemistry Chinese Academy of Sciences, Guangzhou 510650, China 中科院化学所北京

Ethyl-cyanoethyl cellulose [(E-CE)C]/acrylic acid (AA) becomes a cholesteric liquid crystalline solution withvivid colors when the (E-CE)C concentration is 42 wt%～52 wt%. (E-CE)C/polyacrylic acid (PAA) composites withcholesteric structure were prepared by polymerzing AA in (E-CE)C/AA liquid crystalline solutions. The layers of orderedpolymer chains in the cholesteric phase were inclined during polymerization and the degree of the inclination depended onthe polymerization temperature and the concentration of the solution before polymerization. The cholesteric structure in thecomposites could not be changed when temperature was lower than 100℃. Cross-linking of the PAA in compositesimproved their water-resistance. The cholesteric order of the composites without cross-linking was destroyed when theywhere immersed in water. The color derived from the selective reflection of the cholesteric phase of the cross-linkedcomposites turned from blue to red after the composites absorbed water. The color of the composites could be returned to theoriginal one when the absorbed water was removed from the swollen composites.

关键词： Cholesteric structure Composites Selective reflection Liquid crystalline solutions

Collapse Simulation and Response Assessment of a Large Cooling Tower Subjected to Strong Earthquake Ground Motions

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Computer Modeling in Engineering & Sciences 2020年第5期123卷 691-715页

作者： Tiancan Huang Hao Zhou Hamid Beiraghi Earthquake Engineering Research&Test Center Guangzhou UniversityGuangzhou510405China Department of Civil Engineering South China University of TechnologyGuangzhou510641China Department of Civil Engineering Mahdishahr BranchIslamic Azad UniversityMahdi Shahr***Iran

Large cooling towers in thermal power plants and nuclear power plants are likely to suffer from strong earthquakes during service *** resulting destructions of the cooling towers would endanger the power plants and threaten the security of the related *** is important to use effective means to evaluate the safety status of the cooling towers and guide further precautions as well as retrofitting *** paper is therefore focused on an elaborate numerical investigation to the earthquake-induced collapses of a large cooling tower structure.A complete numerical work for simulation of material failure,component fracture,structural buckling and system collapse is presented by integrating the stochastic damage constitutive model of concrete,refined structural element models,and some other key *** results indicate that the damage behavior and collapse mode of the cooling tower are affected notably by the randomness specification of ground *** collapse mechanisms of the cooling tower are studied from the energy absorption and dissipation points of *** effective energy-based criterion is introduced to identify the collapse of the cooling tower under ground motion *** distinct collapse modes are observed,the collapse criterion can predict well the damage and failure of the cooling *** proposed methodology is vital to better understanding the disastrous mechanisms and potential failure paths in optimal design of the cooling towers to ensure safety.

关键词： Cooling tower concrete damage mechanics collapse criterion responses

Development of temperature-robust damage factor based on sensor fusion for a wind turbine structure

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Frontiers of Structural and Civil Engineering 2015年第1期9卷 42-47页

作者： Jong-Woong PARK Sung-Han SIM Jin-Hak YI Hyung-Jo JUNG Department of Civil and Environmental Engineering University of Illinois at Urbana-Champaign Urbana IL 61801 USA School of Urban and Environmental Engineering Ulsan National Institute of Science and Technology (UNIST) Ulsan 689- 798Republic of Korea Coastal Development & Ocean Engineering Research Division Korea Institute of Ocean Science and Technology Ansan 426-744Republic of Korea Department of Civil and Environmental Engineering KAIST Daejeon 305-701 Republic of Korea

Wind power systems have gained much attention due to the relatively high reliability, maturity in technology and cost competitiveness compared to other renewable alternatives. Advances have been made to increase the power efficiency of the wind turbines while less attention has been focused on structural integrity assessment of the structural systems. Vibration-based damage detection has widely been researched to identify damages on a structure based on change in d^mmic characteristics. Widely spread methods are natural frequency-based, mode shape-based, and curvature mode shape-based methods. The natural frequency-based methods are convenient but vulnerable to environmental temperature variation which degrades damage detection capability; mode shapes are less influenced by temperature variation and able to locate damage but requires extensive sensor instrumentation which is costly and vulnerable to signal noises. This study proposes novelty of damage factor based on sensor fusion to exclude effect of temperature variation. The combined use of an accelerometer and an inclinometer was considered and damage factor was defined as a change in relationship between those two measurements. The advantages of the proposed method are： 1） requirement of small number of sensor, 2） robusmess to change in temperature and signal noise and 3） ability to roughly locate damage. Validation of the proposed method is carried out through numerical simulation on a simplified 5 MW wind turbine model.

关键词： sensor fusion damage detection structural health monitoring

Preparation of click-driven cross-linked anion exchange membranes with low water uptake

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Particuology 2020年第1期18卷 65-73页

作者： Abhishek N.Mondal Jianqiu Hou Yubin He Liang Wu Liang Ge Tongwen Xu CAS Key Laboratory of Soft Matter Chemistry Collaborative Innovation Center of Chemistry for Energy MaterialsSchool of Chemistry and Material ScienceUniversity of Science and Technology of ChinaHefei 230026China

Significant advancement in anion exchange membrane(AEM)fuel cell(AEMFC)technology is important in the field of renewable *** with comb-shaped architectures have attracted considerable research interest because of some unique features,including high anion conductivity,low swelling,and high alkaline ***,we report preparation,characterization,and performance evaluation of a novel comb-shaped cross-linked AEM synthesized by the thiol-ene click and Menshutkin *** prepared ionomer decreases the trade-off between the water uptake and the *** thiol-ene click reaction was used to synthesize the 1,14-di(1H-imidazol-1-yl)-6,9-dioxa-3,12-dithiatetradecane(IDDT)*** was then introduced into the brominated poly(2,6-dimethyl-1,4-phenylene oxide)backbone by the Menshutkin *** prepared ionomers show high thermomechanical stability,which is needed in AEMFC *** CLINK-15-100 membrane(ion exchange capacity 1.23 mmol/g)shows relatively good conductivities of 19.66 and 34.91 mS/cm at 30 and 60℃,***,the membrane shows water uptake of only 14.22%at room temperature,which is considerably lower than many previously reported *** 16 days of alkaline treatment in 1 M NaOH solution at 60℃,the CLINK-15-100 membrane retains 77%of its initial conductivity,which is much better than the traditional quaternized poly(2,6-dimethyl-1,4-phenylene oxide)membrane.

关键词： Anion exchange membrane Fuel cell Thiol-ene click reaction Water uptake Comb-shaped architecture

Exact Variational Principle For 3-D Unsteady Heat Conduction With Second Sound

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Journal of Thermal Science 2006年第4期15卷 361-363页

作者： Gaolian LIU Institute of Mechanics Shanghai University Shanghai 200072 China

The exact variational formulation of the extended unsteady heat conduction equation with finite propagation speed （the 2nd sound speed） of hyperbolic type is derived herein via a systematic and natural way. Moreover, the boundary- and the physically acceptable initial-value conditions are accommodated in the variational principle by a novel method suggested just recently. In this way a perfect justification of the variational theory of transient heat conduction and a rigorous theoretical basis for the finite element analysis of heat conduction are provided.

关键词： variational principle unsteady heat conduction finite element method

Synthesis and Characterization of A Novel Cholesteric Liquid Crystalline Containing Carboxyl Group

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Chinese Chemical Letters 2005年第1期16卷 127-130页

作者： JingMA YingNanXUAN YongHUANG KeyLaboratoryofCelluloseandLignocellulosicsChemistry GuangzhouInstituteofChemistryChineseAcademyofSciencesGuangzhou510650／／GraduateSchooloftheChineseAcademyofSciencesBe~jing100039

A novel liquid crystal compound with a carboxyl group at one end, cholest-5-en-3-ol- (3β) hydrogen decanedioate (1) was successfuly prepared by the reaction of cholesterol with sebacoyl chloride. Its chemical structure and liquid crystalline properties were characterized by FTIR, CNMR, 1HNMR, POM and DSC. The compound with an active carboxyl group shows 13 themortropic liquid crystalline behaviour.

关键词： Liquid crystal cholesterol themortropic texture.

First-principles study of structural stability and elastic properties of MgPd_(3) and its hydride

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Journal of Magnesium and Alloys 2014年第2期2卷 165-174页

作者： Dong-Hai Wu Hai-Chen Wang Liu-Ting Wei Rong-Kai Pan Bi-Yu Tang School of Chemistry and Chemical Engineering Guangxi UniversityNanning 530004China Department of Physics Xiangtan UniversityHunan Province 411105China

Theoretical study of structural stability and elastic properties ofα-andβ-MgPd_(3)intermetallic compounds as well as their hydrides have been carried out based on density functional *** results indicateα-MgPd_(3)is more stable thanβphase with increased stability in their *** calculated elastic constants ofα-MgPd_(3)are overall larger thanβ*** hydrogenation,the elastic constants are *** the elastic moduli exhibit similar *** anisotropy ofα-MgPd_(3)is larger thanβphase,and the hydrides demonstrate larger *** ductility follows the order ofα-MgPd_(3)H_(0.5)<α-MgPd_(3)<β-MgPd_(3)H<β-MgPd_(3).Compared withβphase,higher Debye temperature ofα-MgPd_(3)implies stronger covalent interaction,and the Debye temperature of hydrides increases *** electronic structures demonstrate that the Pd-Pd interaction is stronger than Pd-Mg,and Pd-H bonds play a significant role in the phase stability and elastic properties of hydrides.

关键词： First-principles Stability Elastic properties Electronic structure MgPd_(3)

Evaluation of maize inbred lines currently used in Chinese breeding programs for resistance to six foliar diseases

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The Crop Journal 2014年第4期2卷 213-222页

作者： Xiaoming Wang Yunhua Zhang Xiude Xu Hongjie Li Xiaofei Wu Shihuang Zhang Xinhai Li The National Key Facility for Crop Gene Resources and Genetic Improvement Institute of Crop Science Chinese Academy of Agricultural Sciences Institute of Plant Protection Heilongjiang Academy of Agricultural Sciences Institute of Plant Protection Liaoning Academy of Agricultural Sciences

Foliar diseases are common in most maize-producing regions and have caused serious yield reduction in China. To evaluate genetic resistance of parental lines actively used in maize breeding programs to major foliar diseases, 152 maize inbred lines were tested against northern corn leaf blight(NCLB), southern corn leaf blight(SCLB), Curvularia leaf spot(CLS),gray leaf spot(GLS), common rust, and southern rust from 2003 to 2005. A small number of lines exhibited highly resistant reactions to common rust and southern rust, but none were highly resistant to NCLB, SCLB, CLS, and GLS. Although 53.3%, 40.8%, and 80.7% of lines were resistant to NCLB, SCLB, and common rust, the resistance in most lines was *** to CLS, GLS, and southern rust was rare in this collection of maize lines. Five lines,313, Chang 7-2, Qi 319, Qi 318, and Shen 137, were resistant to five diseases tested. Lines belonging to heterotic subgroup PB exhibited better resistance to the foliar diseases than lines from other heterotic subgroups, such as BSSS, PA, Lancaster, LRC, and PA. The results will be of benefit to breeders for selecting lines in disease resistance breeding programs.

关键词： Zea mays Screening Resistance Fungal diseases