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Preparation and Characterization of Polylactide/Montmorillonite Nanocomposites

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Journal of wuhan University of Technology(Materials Science) 2009年第4期24卷 562-565页

作者：吴选军 School of Chemical engineering Wuhan University of Technology

The montmorillonite, a form of layered silicate, was successfully intercalated into polylactide （PLA） matrix through solvent-casting technique. In addition, PLA/MMT nanocomposite films were produced, in which homogenous distribution of the silicate lamellae plays a key role in the mechanical properties of the films. A small amount（5wt%） of OMMT intercalated into the PLA matrix resulted in their flexibility enhancement, from 3.68%（pure PLA film） to 352.65%. The results of wide-angle X-ray diffraction （WAXD） patterns confirmed that the silicate interlayer distance increased from 3.044 nm （for OMMT） to 3.56nm （for 5wt%, maximum） with increasing OMMT contents, but decreased to 3.319 nm when OMMT content was over 8wt%. FT-IR also verified the molecular-level associations between PLA chains and OMMT lamellae by vibration variances of hydrogen bonding. DSC thermograms demonstrated that thermal stabilities of the nanocomposite films enhanced, due to the silicate lamellae dispersed into PLA matrix.

关键词： polylactide montmorillonite nanocomposite characterization thermo-mechanic at property

Assessing a soft twin tunneling numerical model using field data

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Journal of Pharmaceutical Analysis 2009年第1期21卷 36-41页

作者： Ke-shuan Ma1,2.Lie-yun Ding11. School of Civil engineering and Mechanics,hubei Key Laboratory of Control Structure, Huazhong University of Science & Technology,{2., china 2. Department of Civil engineering, Nanyang institute of Technology, Nanyang 473004, china. School of Civil engineering and Mechanics Hubei Key Laboratory of Control Structure Huazhong University of Science and Technology Wuhan 430074 China Department of Civil engineering Nanyang Institute of Technology Nanyang 473004 China

Using a five-floor building affected by the Yangtze River highway tunnels in wuhan as the engineering background, we have constructed a free-field model and a coupled model to study the soil, lining, foundations and upper structure, and analyze the rules of movements of building foundation and ground induced by single tunnel and twin tunnel excavation with the Finite Element Analysis method. It is shown that for the coupled model, the longitudinal displacement of each foundation increases slowly when the tunnel face gets close to the foundation section and then increases fast when the tunnel face moves away from the foundation during the single and twin tunneling. For a single tunnel, the surface settlements are overestimated by the free-field and coupled tunnel. This might be crucial in urban areas. Regarding the maximum settlements and the width of the settlement trough, the difference between the free-field model and the coupled model is quite obvious. This comparison with the field measurement value reveals that the coupled model seems to be superior to the free-field model. These results are of instructive significance for design and excavation.

关键词： finite element analysis three-dimensional slurry shield tunneling building settlement

Modification of Fluorgypsum as Cement Retarder

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Journal of wuhan University of Technology(Materials Science) 2007年第4期22卷 745-748页

作者：王锦华 School of Materials Science and engineering Wuhan University of Technology

The chemical composition and mineral structure of fluorgypsum as well as its harm to application in cement were elaborately analyzed. The primary fluorgypsum was modified and its applications in cement＇s production were studied. The technological flow chart of preparing modified fluorgypsum was given. Experimental results indicate that hydration ratio the modified fluorgypsum through adding compound additive for 14d is about 70%. The modified fluorgypsum as cement retarder has certain stimulation to fly ash and increases the strength of compound cement. In addition, its adding amount is lower than that of natural gypsum. The modified fluorgypsum is a good substitute for natural gypsum.

关键词： fluorgypsum industry waste modification cement retarder

Nonstationary clutter suppression for airborne conformal array radar

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Science china(Information Sciences) 2011年第10期54卷 2170-2177页

作者： DUAN KeQing 1,2.XIE WenChong 2.& WANG YongLiang 2. 1 School of Electronic Science and engineering,National University of Defense Technology,Changsha 410073,china 2.Key {2. Lab,wuhan Radar Academy,wuhan 430019,china School of Electronic Science and engineering National University of Defense Technology Changsha China Key research Lab Wuhan Radar Academy Wuhan China

The essence of nonstationary clutter for airborne radar with conformal antennas array (CAA) is analyzed,and an angle-Doppler compensation method for clutter suppression is *** with the uniform linear antennas array (LAA),the clutter angle-Doppler spectrum distribution of CAA should be described in four-dimension space,i.e.,three-dimension space and time,because the elements of CAA are distributed in three-dimension *** to this theory,the clutter nonstationarity for airborne radar with CAA is firstly analyzed and the nonstationary nature of it is *** an improved STAP method for airborne radar with CAA is proposed,and it compensates for the mainlobe clutter in four-dimension frequency ***,the simulation results show the effect of the novel method.

关键词： conformal antennas array (CAA) space-time adaptive processing (STAP) nonstationarity clutter suppression

Phenomenon of “contact guidance” on the surface with nano-micro-groove-like pattern and cell physiological effects

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Chinese Science Bulletin 2009年第18期54卷 3200-3205页

作者： ZHOU Feng 1,2. YUAN Lin 1,3, HUANG He 1,2.& CHEN Hong1,2.1 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, wuhan 430070, china 2.School of Materials Science and {2., wuhan University of Technology, wuhan 430070, china 3 Biomedical Materials research Center, wuhan University of Technology, wuhan 430070, china State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan China School of Materials Science and engineering Wuhan University of Technology Wuhan China Biomedical Materials research Center Wuhan University of Technology Wuhan China

The topography of material surface has important influence on cell behavior and physiological functions. Groove-like pattern has drawn much attention among various patterns, due to the phenomenon of "contact guidance" induced by this kind of topography. This review mainly focuses on "contact guidance" formation as well as its influence on cell behavior and physiological effects. The possible mechanisms of "contact guidance" formation were discussed. The research trend and the potential applications were also suggested.

关键词：细胞行为生理功能材料表面逻辑效应触指纳米微米生理效应

GEAR CRACK EARLY DIAGNOSIS USING BISPECTRUM DIAGONAL SLICE

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Chinese Journal of Mechanical engineering 2003年第2期16卷 193-196页

作者： Li WeihuaZhang GuicaiShi TielinYang ShuziSchool of Mechanical Scienceand engineering,Huazhong University of Scienceand Technology,wuhan {2., china School of Mechanical Science and engineering Huazhong University of Science and Technology Wuhan 430074

A study of bispectral analysis in gearbox condition monitoring is *** theory of bispectrum and quadratic phase coupling (QPC) is first introduced, and then equationsfor computing bispectrum slices are obtained. To meet the needs of online monitoring, a simplifiedmethod of computing bispectrum diagonal slice is adopted. Industrial gearbox vibration signalsmeasured from normal and tooth cracked conditions are analyzed using the above method. Experimentsresults indicate that bispectrum can effectively suppress the additive Gaussian noise andchracterize the QPC phenomenon. It is also shown that the 1-D bispectrum diagonal slice can capturethe non-Gaussian and nonlinear feature of gearbox vibration when crack occurred, hence, this methodcan be employed to gearbox real time monitoring and early diagnosis.

关键词： condition monitoring gear crack early diagnosis quadratic phase coupling bispectrum diagonal slice

On the new results of global attractive set and positive invariant set of the Lorenz chaotic system and the applications to chaos control and synchronization

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Science in china(Series F) 2005年第3期48卷 304-321页

作者： LIAO Xiaoxin 1, 2. 3 , FU Yuli 4 & XIE Shengli 4 1. Department of Control Science & Control engineering, Huazhong University of Science & Technology, wuhan 430074,{2. 2. School of Automation, wuhan University of Science & Technology, wuhan 430070,{2. 3. School of Information, Central South University of Economy, Politics and Law, wuhan 430064,{2. 4. School of Electronics & Information engineering, South{2. University of Technology, Guangzhou 510640,{2. Correspondence should be addressed to Liao Xiaoxin (email: xiaoxin_liao@***) Department of Control Science & Control engineering Huazhong University of Science & Technology Wuhan China School of Automation Wuhan University of Science & Technology Wuhan China School of Information Central South University of Economy Politics and Law Wuhan China School of Electronics & Information engineering South China University of Technology Guangzhou China

Constructing a family of generalized Lyapunov functions, a new method is proposed to obtain new global attractive set and positive invariant set of the Lorenz chaotic system. The method we proposed greatly simplifies the complex proofs of the two famous estimations presented by the Russian scholar Leonov. Our uniform formula can derive a series of the new estimations. Employing the idea of intersection in set theory, we extract a new Leonov formula-like estimation from the family of the estimations. With our method and the new estimation, one can confirm that there are no equilibrium, periodic solutions, almost periodic motions, wandering motions or other chaotic attractors outside the global attractive set. The Lorenz butterfly-like singular attractors are located in the global attractive set only. This result is applied to the chaos control and chaos synchronization. Some feedback control laws are obtained to guarantee that all the trajectories of the Lorenz systems track a periodic solution, or globally stabilize an unstable (or locally stable but not globally asymptotically stable) equilibrium. Further, some new global exponential chaos synchronization results are presented. Our new method and the new results are expected to be applied in real secure communication systems.

关键词： Lorenz chaotic system global attractive set positive invariant set globally exponential tracking globally exponential synchronization.

Extended multivariate public key cryptosystems with secure encryption function

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Science china(Information Sciences) 2011年第6期54卷 1161-1171页

作者： WANG HouZhen 1,2., ZHANG HuanGuo 1,2., WANG ZhangYi 1,2.& TANG Ming 1,2.1 The Key Laboratory of Aerospace Information Security and Trusted Computing, Ministry of Education, School of Computer, wuhan University, wuhan 430079,{2. 2.State Key Laboratory of Software engineering, wuhan University, wuhan 430072.{2. The Key Laboratory of Aerospace Information Security and Trusted Computing Ministry of Education School of Computer Wuhan University Wuhan China State Key Laboratory of Software engineering Wuhan University Wuhan China

Advances in quantum computers pose great threats on the currently used public key cryptographic algorithms such as RSA and ECC. As a promising candidate secure against attackers equipped with quantum computational power, multivariate public key cryptosystems (MPKCs) have attracted increasing attention in recently years. Unfortunately, the existing MPKCs can only be used as a multivariate signature scheme, and it remains unknown how to construct an efficient MPKC enabling secure encryption. Furthermore, some multivariate signature schemes have been shown insecure in recent years, and it is also not trivial to build MPKC which can serve as a secure signature scheme. By employing the basic MQ-trapdoors, this paper proposes a novel MPKC and shows how it can be used as a multivariate signature scheme and a multivariate encryption scheme, respectively. The goal is achieved by incorporating our new hash authentication techniques and some modification methods such as the Shamir's minus method. Thorough analysis shows that our schemes are secure and efficient. Our MPKC gives a positive response to the challenges in multivariate public key cryptography.

关键词： cryptography post-quantum cryptography MQ problem hash function

Detection of bursts in neuronal spike trains by the mean inter-spike interval method

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Progress in Natural Science:Materials International 2009年第2期19卷 229-235页

作者： Lin Chena,b,Yong Deng c,Weihua Luo a,Zhen Wang a,Shaoqun Zenga,a hubei Bioinformatics and Molecular Imaging Key Laboratory,Huazhong University of Science and Technology,wuhan {2.,china b College of Mechanical engineering,Guangxi University,Nanning,530004,china c College of Optoelectronic Science of engineering,Huazhong University of Science and Technology,wuhan {2.,china hubei Bioinformatics and Molecular Imaging Key Laboratory Huazhong University of Science and Technology Wuhan 430074 China College of Mechanical engineering Guangxi University Nanning 530004 China College of Optoelectronic Science of engineering Huazhong University of Science and Technology Wuhan 430074 China

Bursts are electrical spikes firing with a high frequency,which are the most important property in synaptic plasticity and information processing in the central nervous system. However,bursts are difficult to identify because bursting activities or patterns vary with phys-iological conditions or external stimuli. In this paper,a simple method automatically to detect bursts in spike trains is described. This method auto-adaptively sets a parameter (mean inter-spike interval) according to intrinsic properties of the detected burst spike trains,without any arbitrary choices or any operator judgment. When the mean value of several successive inter-spike intervals is not larger than the parameter,a burst is identified. By this method,bursts can be automatically extracted from different bursting patterns of cultured neurons on multi-electrode arrays,as accurately as by visual inspection. Furthermore,significant changes of burst variables caused by electrical stimulus have been found in spontaneous activity of neuronal network. These suggest that the mean inter-spike interval method is robust for detecting changes in burst patterns and characteristics induced by environmental alterations.

关键词： Inter-spike interval Bursts Spike trains Multi-electrode arrays