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ENHANCED MECHANICAL PROPERTIES OF POLYPROPYLENE/SILICA NANOCOMPOSITES WITH SURFACE MODIFICATION OF NANO-SILICA VIA IN SITU COPOLYMERIZATION OF METHYL METHACRYLATE AND BUTYL ACRYLATE

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Chinese Journal of Polymer Science 2009年第5期27卷 685-694页

作者： Yiu-wing mai Center for Advanced Materials Technology School of AerospaceMechanical and Mechatronic EngineeringJ07University of Sydney

Nano-sized silica particles were modified with methacryloxy-propyltrimethoxysilane(MPS) followed by in situ copolymerization of methyl methacrylate(MMA) and butyl acrylate(BA).These modified nanoparticles were compounded with polypropylene(PP) to prepare PP/silica *** grafted on nano-silica enhances the dispersion of the nanoparticles and interfacial adhesion,decreases the size of PP spherulites in nanocomposites and leads to increasing the Young's modulus and toughness of PP/silica nanocomp...

关键词： Nano composites Interface Mechanical properties.

Discrete decision model and multi-agent simulation of the Liang Zong two-chain hierarchical organization in a complex project

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Journal of Systems Engineering and Electronics 2018年第2期29卷 311-320页

作者： mai Qiang ZHAO Yueqiang AN Shi School of Management Harbin Institute of Technology Defense Technology Academy China Aerospace Science & Industry Corporation

Different from the organization structure of complex projects in Western countries, the Liang Zong hierarchical organization structure of complex projects in China has two different chains, the chief-engineer chain and the general-director chain,to handle the trade-off between technical and management decisions. However, previous works on organization search have mainly focused on the single-chain hierarchical organization in which all decisions are regarded as homogeneous. The heterogeneity and the interdependency between technical decisions and management decisions have been neglected. A two-chain hierarchical organization structure mapped from a real complex project is constructed. Then, a discrete decision model for a Liang Zong two-chain hierarchical organization in an NK model framework is proposed. This model proves that this kind of organization structure can reduce the search space by a large amount and that the search process should reach a final stable state more quickly. For a more complicated decision mechanism, a multi-agent simulation based on the above NK model is used to explore the effect of the two-chain organization structure on the speed, stability, and performance of the search process. The results provide three insights into how, compared with the single-chain hierarchical organization, the two-chain organization can improve the search process: it can reduce the number of iterations efficiently; the search is more stable because the search space is a smoother hill-like fitness landscape; in general, the search performance can be ***, when the organization structure is very complicated, the performance of a two-chain organization is inferior to that of a single-chain organization. These findings about the efficiency of the unique Chinese-style organization structure can be used to guide organization design for complex projects.

关键词： complex project two-chain hierarchical organization discrete decision model multi-agent simulation

Effects of precipitates and inclusions on the fracture toughness of hot rolling X70 pipeline steel plates

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International Journal of Minerals,Metallurgy and Materials 2012年第9期19卷 805-811页

作者： mai-wen Zhou Hao Yu School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China

In order to investigate the fracture toughness, crack tip opening displacement （CTOD） experiments were conducted on two X70 pipeline steel plates with different rolling processes. Atter the experiments, optical microscopy （OM）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM） were employed to observe the microstructure and fracture morphology. The effects of precipi- tates on the fracture toughness and the crack initiation mechanism induced by inclusions were analyzed. The CTOD result shows that the steel with a lower finishing cooling temperature has a higher fracture toughness. Inchisiom with different shapes and two kinds of precipi- tates with different sizes were observed. It can be concluded that precipitates with different sizes have different effects and mechanisms on the fracture toughness. Distinguished fi＇om the earlier researches, inclusions enriched in silicon can be also served as the crack initiation.

关键词： pipeline steel crack propagation precipitates inclusions fracture toughness

Forced Time-Dependent Harmonic Oscillators in Non-Commutative Space

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Communications in Theoretical Physics 2011年第3期55卷 410-414页

作者： LIANG mai-Lin Physics Department School of Science Tianjin University Tianjin 300072 China

For the time-dependent harmonic oscillator and generalized harmonic oscillator with or without external forces in non-commutative space, wave functions, and geometric phases are derived using the Lewis-Riesenfeld invariant. Coherent states are obtedned as the ground state of the forced system. Quantum fluctuations are calculated too. It is seen that geometric phases and quantum fluctuations are greatly affected by the non-commutativity of the space.

关键词： non-commutative quantum mechanics harmonic oscillator geometric phase coherent state

Mesoporous cobalt oxide for largely improved lithium storage properties

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Chinese Chemical Letters 2012年第8期23卷 949-952页

作者： mai Xia Ma Faculty of Chemistry and Material Science Langfang Teachers CollegeLangfang 065000China

We report the microstructure, application for lithium-ion batteries of mesoporous Co304 prepared by modified KIT-6 template method. The sample was characterized by XRD, TEM, HRTEM and nitrogen adsorption. Their electrochemical behaviors as electrode reactants for lithium ion batteries were evaluated by cyclic voltammograms and static charge-discharge. A direct comparison of electrochemical behaviors between mesoporous nanostructure and bulk reflects interesting ＂nanostructure effect＂, which is reasonably discussed in terms of how the 3D nanostructures of Co3O4 materials function in tuning their electrochemistry. The results demonstrate that further improvement of electrochemical performance in transition metal-oxide-based anode materials can be realized via the design of multiporous nanostructured materials.

关键词： Mesoporous Co3O4 High lithium storage capacity Nanostructure effect

Existing Regions of Either Rarefactive or Compressive Solitary Waves for Particular Dusty Plasma

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Communications in Theoretical Physics 2008年第2期49卷 482-484页

作者： GAO Xiu-Yun LIN mai-mai DUAN Wen-Shan College of Physics and Electronic Engineering Northwest Normal University Lanzhou 730070 China

By deriving a Korteweg-de Vries （KdV） equation for particular dusty plasma, we find the existing regions of solitary waves. The regions of both rarefactive and compressive solitary waves have also been given in this... 详细信息

关键词： dust acoustic solitary waves KdV equation

Robust Finite-Time Stability and Stabilization of a Class of Fractional-Order Switched Nonlinear Systems

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Journal of Systems Science & Complexity 2019年第6期32卷 1479-1497页

作者： mai Viet Thuan DINH Cong Huong Department for Management of Science and Technology Development Ton Due Thang UniversityHo Chi Minh CityVietnam Faculty of Mathematics and Statistics Ton Due Thang UniversityHo Chi Minh CityVietnam Department of Mathematics Quynhon UniversityBinhdinhVietnam

This paper deals with the problem of finite-time boundedness and fin计e-time stabilization boundedness of frax?tional-order switched nonlinear systems with exogenous *** constructing a simple Lyapunov-like function and using some properties of Caputo derivative,the authors obtain some new sufficient conditions for the problem via linear matrix inequalities,which can be efficiently solved by using existing convex algorithms.A constructive geometric is used to design switching laws amongst the *** obtained results are more general and useful than some existing works,and cover them as special cases,in which only linear fractional-order systems were *** examples are provided to demonstrate the effectiveness of the proposed results.

关键词： Caputo fractional-order derivative finite-time boundedness fractional-order switched systems linear matrix inequalities

Preparation of hydrogels with uniform and gradient chemical structures using dialdehyde cellulose and diamine by aerating ammonia gas

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Frontiers of Chemical Science and Engineering 2018年第3期12卷 383-389页

作者： Peiwen Liu Carsten mai Kai Zhang Wood Technology and Wood Chemistry Georg-August-Universitat Gottingen 37077 Gottingen Germany Wood Biology and Wood Products Georg-August-Universitat Gottingen 37077 Gottingen Germany

Hydrogels with precisely designed structures represent promising materials with a broad application spectrum, such as for sensor, tissue engineering and biomimetic technology. However, with highly reactive compounds, the preparation of hydrogels still needs an efficient approach for desired distribution of each component within hydrogels. In addition, a method for in situ preparation of gradient hydrogels is still lacking. Herein, we report the formation ofhydrogels with either uniform or gradient internal structures via a novel, simple but very efficient method by aerating ammonia gas （NH3 gas） into the solution of dialdehyde cellulose （DAC） and a diamine. As-prepared hydrogels exhibited uniform microscopic and chemical structure or gradient distribution Of functional groups. Due to lots of aldehyde groups on DAC chains, functional hydrogels can be prepared by using diverse diamines. For instance, hydrogels prepared by using 1,6-hexanediamine as a cross-linker were responsive to pH values. Moreover, this controllable process of aerating NH3 gas allows the in situ formation of gradient hydrogels; for instance, by using cyanamide as a reaction counterpart, gradient hydrogels with gradient distributions of cyanide groups were prepared.

关键词： hydrogel uniform gradient dialdehyde cellulose ammonia gas diamine

Seismic fragility curves for structures using non-parametric representations

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Frontiers of Structural and Civil Engineering 2017年第2期11卷 169-186页

作者： Chu mai Katerina KONAKLI Bruno SUDRET Risk Safety & Uncertainty Quantification Institute of Structural Engineering ETH Ziirich Ziirich CH-8093 Switzerland

Fragility curves are commonly used in civil engineering to assess the vulnerability of structures to earthquakes. The probability of failure associated with a prescribed criterion （e.g., the maximal inter-storey drift of a building exceeding a certain threshold） is represented as a function of the intensity of the earthquake ground motion （e.g., peak ground acceleration or spectral acceleration）. The classical approach relies on assuming a lognormal shape of the fragility curves; it is thus parametric. In this paper, we introduce two non-parametric approaches to establish the fragility curves without employing the above assumption, namely binned Monte Carlo simulation and kernel density estimation. As an illustration, we compute the fragility curves for a three-storey steel frame using a large number of synthetic ground motions. The curves obtained with the non-parametric approaches are compared with respective curves based on the lognormal assumption. A similar comparison is presented for a case when a limited number of recorded ground motions is available. It is found that the accuracy of the lognormal curves depends on the ground motion intensity measure, the failure criterion and most importantly, on the employed method for estimating the parameters of the lognormal shape.

关键词： earthquake engineering fragility curves lognormal assumption non-parametric approach kernel density estimation epistemic uncertainty