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A numerical study on nonlinear propagation and short-term variability of the migrating diurnal and semidiurnal tides

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Chinese science Bulletin 2005年第17期50卷 1940-1948页

作者： HUANG Chunming1,2. ZHANG Shaodong1,2.& YI Fan1,2.1. school of Electronic Information, wuhan Universiy, wuhan 430079, china 2. Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, wuhan university, wuhan 430079, china school of Electronic Information Wuhan University Wuhan 430079 China Key Laboratory of Geospace Environment and Geodesy Ministry of Education Wuhan University Wuhan 430079 China

By using a three-dimensional fully nonlinear numerical model in spherical coordinates and taking the linear steady solutions of the migrating diurnal and semidi-urnal tides in January from the Global-Scale Wave Model (GSWM) as the initial values, we simulate the linear and nonlinear propagations of the migrating diurnal and semidi-urnal tides in the atmosphere from the ground to the lower thermosphere. A comparison of our simulations with the results of GSWM is also presented. The simulation results show that affected by the nonlinearity, the migrating diurnal and semidiurnal tides propagating in the middle and upper atmosphere exhibit evident short-term variability. The nonlinear interactions between the migrating tides and the background atmosphere can obviously alter the background wind and temperature fields, which suggests that the nonlin-ear propagations of the migrating diurnal and semidiurnal tides impact significantly on the transient dynamical and thermal structures of the background middle and upper at-mosphere and the nonlinear effect is an important cause of the difference between the results of GSWM and observa-tions.

关键词：大气非线性传播数学模型可变性温度场

Exsolution of ilmenite and Cr-Ti magnetite from olivine of garnet-wehrlite

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science china Earth sciences 2005年第9期48卷 1368-1376页

作者： LIU Xiangwen1,2. JIN Zhenmin1,3, QU Jing2.& WANG Lu2.1. State Key Laboratory of Geological Processes and Mineral Resources, china university of Geo{2.s, wuhan 430074, china 2. Graduate school of china university of Geo{2.s, wuhan 430074, china 3. Faculty of Earth {2.s, china university of Geo{2.s, wuhan 430074, china 1. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences 430074 Wuhan China 2. Graduate school of china {2. of Geosciences 430074 Wuhan China 3. Faculty of Earth sciences China University of Geosciences 430074 Wuhan China

Exsolution of rod-like ilmenite (Ilm) and Cr-Ti magnetite (Mt) have been found in olivine of garnet-wehrlite from the core of Chinese Continental sciences Drilling (CCSD). Their composition, morphology, crystal structure and their topotaxies with host olivine have been studied in detail by the transmission electron microscopy (TEM) and electron probe microanaly- sis (EPMA) technique. It shows that rod-like Ilm exsolution reported in this paper has similar characteristic with that of Alpe Arami olivine, while Cr-Ti magnetite exsolution mentioned in this paper has large discrepancy with chromite exsolution in Alpe Arami olivine. These observations suggest that both of the exsolutions found in this paper should be solid solution phases in β-olivine at their first period, then experiencing decomposition of solid solution and therefore forming Ilm and Cr-Ti magnetite exsolution with the pressure decreasing. So, this garnet-wehrlite perhaps had been ever located in mantle transition zone with a minimum depth of 300 km.

关键词： garnet-wehrlite, ilmenite, magnetite, exsolution, CCSD.

A Hybrid Genetic Algorithm for Reduct of Attributes in Decision System Based on Rough Set Theory

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wuhan university Journal of Natural {2.s 2002年第3期7卷 285-289页

作者： Dai Jian\|hua 1,2., Li Yuan\|xiang 1,2.,Liu Qun 3 1. State Key Laboratory of Software Engineering, wuhan university, wuhan 430072. Hubei,china 2. school of Computer, wuhan university, wuhan 430072. Hubei, china 3. school of Computer science, wuhan university State Key Laboratory of Software Engineering Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) wuhan university School of Computer Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) Chongqing university of Posts & Telecommunications School of Computer Science Chongqing China (GRID:grid.411587.e) (ISNI:***)

Knowledge reduction is an important issue when dealing with huge amounts of data. And it has been proved that computing the minimal reduct of decision system is NP-complete. By introducing heuristic information into genetic algorithm, we proposed a heuristic genetic algorithm. In the genetic algorithm, we constructed a new operator to maintaining the classification ability. The experiment shows that our algorithm is efficient and effective for minimal reduct, even for the special example that the simple heuristic algorithm can’t get the right result.

关键词： rough set reduction genetic algorithm heuristic algorithm

Indeterminate direction relation model based on fuzzy description framework

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science china(Technological sciences) 2008年第S1期51卷 72-80页

作者： LIU YaoLin1,HE JianHua1,YU Yan2.& TANG XinMing3 1 school of Resource and Environment science,{2. university,{2. 430079,china 2.school of Resource and Environment Engineer,{2. university of Technology,wuhan 4.0070,china 3 Chinese Academy of Surveying and Mapping,Beijing 10083,china school of Resource and Environment science Wuhan University Wuhan 430079 China school of Resource and Environment Engineer Wuhan University of Technology Wuhan 430070 China Chinese Academy of Surveying and Mapping Beijing 10083 China

The indetermination of direction relation is a hot topic for fuzzy GIS researchers. The existing models only study the effects of indetermination of spatial objects,but ignore the uncertainty of direction reference framework. In this paper,first a for-malized representation model of indeterminate spatial objects is designed based on quadruple (x,y,A,μ),then a fuzzy direction reference framework is constructed by revising the cone method,in which the partitions of direction tiles are smooth and continuous,and two neighboring sections are overlapped in the transitional zones with fuzzy method. Grounded on these,a fuzzy description model for indeterminate direction relation is proposed in which the uncertainty of all three parts (source object,reference object and reference frame) is taken into account simultaneously. In the end,case studies are implemented to test the rationality and validity of the model.

关键词： direction relation fuzzy description framework fuzzy representation model uncertainty

Synthesis and Characterization of Ibuprofen-Rectorite Composites by Solution Intercalation Method

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Journal of wuhan university of Technology(Materials {2.) 2009年第4期24卷 654-657页

作者：王慧燕 Hospital Wuhan University of Teehnology

The ibuprofen-rectorite composites were prepared by the solution intercalation method using ibuprofen and rectorite as raw materials, and were characterized by X-ray diffraction （XRD） analysis, Fourier transform infrared analysis and scanning electron microscopy （SEM）. The experimental results show that the ibuprofen is intercalated into the interlayer spaces of rectorite. The values of the （001） peaks of the ibuprofen-rectorite composite are larger than that of Na-rectorite and reach the largest when the reaction time and ibuprofen amount is 2.h and 0.36 g, respectively. The layered structure of Na-rectorite is destroyed to some extent with the intercalation of ibuprofen into the interlayer space in the structure of Na-rectorite. A part of ibuprofen in the ibuprofen Na-rectorite covers on the surface of Na-rectorite besides some ibuprofen enters into the interlayer space.

关键词： ibuprofen rectorite solution intercalation composites clay

An Overview on Wavelet Software Packages

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wuhan university Journal of Natural {2.s 2001年第Z1期6卷 593-600页

作者： Fan Qi\|bin 1, Li Hong 2.1. school of Mathematics and Statistics, wuhan {2., wuhan 430072. china 2. school of Electronic Information, wuhan {2., wuhan 430072. china school of Mathematics and Statistics Wuhan University Wuhan China school of Electronic Information Wuhan University Wuhan China

Wavelet analysis provides very powerful problem\|solving tools for analyzing, encoding, compressing, reconstructing, and modeling signals and images. The amount of wavelets\|related software has been constantly multiplying. Many wavelet analysis tools are widely available. This overview represents a significant survey for many currently available packages. It will be of great benefit to engineers and researchers for using the toolkits and developing new software. The beginner to learning wavelets can also get a great help from the review. If you browse around at some of the Internet sites listed in the reference of this paper, you may find more plentiful wavelet resources.

关键词： wavelet transforms image compression matching pursuit lifting MATLAB

Evolutionary cryptography against multidimensional linear cryptanalysis

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science china(Information sciences) 2011年第12期54卷 2585-2597页

作者： ZHANG HuanGuo 1,2., LI ChunLei 1,2.& TANG Ming 1,2.1 school of Computer, wuhan {2., wuhan 430079, china 2.Key Laboratory of Aerospace Information Security and Trusted Computing of Ministry of Education of china, wuhan {2., wuhan 430079, china 1. school of Computer Wuhan University Wuhan 430079 China2. Key Laboratory of Aerospace Information Security and Trusted Computing of Ministry of Education of China Wuhan University Wuhan 430079 China

The evolutionary cryptosystem is a new cryptosystem proposed by a Chinese researcher recently. This paper studies its security level resisting against multidimensional linear cryptanalysis in this paper. It is shown that the evolutionary cryptosystem possesses higher resistance than its initial fixed cryptosystem does for resisting against multidimensional linear cryptanalysis. Multidimensional generalizations of Matsui's Algorithm 1 and Algorithm 2.based on log-likelihood ratio (LLR) statistics are introduced. By the relationship among the data complexity N , the bit advantage a and the success rate P S of these two multidimensional generalized algorithms, it is proven that more data is needed for attacking the evolutionary cryptosystem than that is needed for attacking its initial fixed cryptosystem when the bit advantage and success rate are identical. Moreover, it is shown that both time complexity and memory complexity for attacking the evolutionary cryptosystem are higher than that of attacking its initial fixed cryptosystem with the same data complexity. The research indicates that the evolutionary cryptosystem is more robust than its initial fixed cryptosystem against the multidimensional linear cryptanalysis.

关键词： information security cryptology evolutionary cryptosystem cryptanalysis multidimensional linear cryptanalysis

MCM-41 Prepared with Ionic Liquid and Cethytrimethylammonium Bromide as Co-templates

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Journal of wuhan university of Technology(Materials {2.) 2009年第1期24卷 25-29页

作者：张光旭 school of Chemical Engineering Wuhan University of Technology College of Chemistry and Molecular sciences Wuhan University

The mesoporous molecular sieves MCM-41 were prepared using room tempera-ture ionic liquid （RTIL） synthesized in laboratory and cethytrimethylammonium bromide （CTAB） as compound templates for the first time. They were prepared under low aging temperature and short aging time. Via characterizing by XRD and nitrogen adsorption instrument, MCM-41 synthesized by this new method exhibited good crystal structure and narrow pore distribution. The following pre-paratory conditions was optimal： the molar ratio of RTIL to CTAB was 1.0∶1.0, aging at 80 ℃, for 40 h and calcined at 540 ℃. It is found that the acidified MCM-41 improves its activity as catalyst over the unmodified ones.

关键词： mesoporous molecular sieve hydrothermal crystallization co-templates ionicliquid MCM-41

Magnesia Modification of Alkali-Activated Slag Fly Ash Cement

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Journal of wuhan university of Technology(Materials {2.) 2011年第1期26卷 121-125页

作者：沈卫国 Key Laboratory of Silicate Materials science and Engineering of Ministry of Education Wuhan University of Technology school of Materials science and Engineering Wuhan University of Technology

A new type of magnesia modification alkali-activated cement was prepared, the strength, setting time, shrinkage ratio and cracking behavior, as well as the composition and structure of the hydration product were investigated. The results indicate that the setting time of this cement is similar to that of the ordinary commercial cements; its strength reaches the standard of 42.5 degree cement, its cracking resistance has been remarkably improved because of the micro-aggregate effect of fly ash and shrinkage compensating of magnesia.

关键词： alkali-activated cement crack magnesia volume stability hydration