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Improve Fractal Compression Encoding Speed Using Feature Extraction and Self-organization Network

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Journal of University of Science and Technology beijing 2001年第4期8卷 306-310页

作者： Berthe Kya, Yang Yang Information Engineering School. University of Science and Technology beijing. beijing 100083. China Information Engineering School University of Science and Technology Beijing Beijing 100083 China

Image compression consists of two main parts: encoding and decoding. One of the important problems of the fractal theory is the long encoding implementation time, which hindered the acceptance of fractal image compression as a practical method. The long encoding time results from the need to perform a large number of domain-range matches, the total encoding time is the product of the number of matches and the time to perform each match. In order to improve encoding speed, a hybrid method combining features extraction and self-organization network has been provided, which is based on the feature extraction approach the comparison pixels by pixels between the feature of range blocks and domains blocks. The efficiency of the new method was been proved by examples.

关键词： image compression fractal theory features extraction self-organization network fractal encoding

Prediction of Rock Burst with Deep Mining Excavation in Linglong Gold Mine

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Journal of University of Science and Technology beijing 2001年第4期8卷 241-243页

作者： Meifeng Cai, Jinan Wang, Shuanghong Wang Civil and Environmental Engineering School, University of Science and Technology beijing, beijing 100083. China Civil and Environmental Engineering School University of Science and Technology Beijing Beijing 100083 China

To predict rock burst in deep mining excavation in Linglong gold mine, systematical laboratory tests of mechanical properties of rock, in situ stress measurement and 3.D FEM analysis on energy distribution in rock mass surrounding deep mining rooms were carried out. According to various prediction criteria of rock burst, it is concluded that rock burst is liable to occur during deep mining excavation in the mine.

关键词： rock burst prediction deep mining excavation Linglong gold mine

Unfolding of a Quadratic Integrable System with a Homoclinic Loop

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Acta Mathematica Sinica,English Series 2002年第4期18卷 737-754页

作者： Lin Ping PENG Department of Applied Mathematics. beijing University of Aeronautics and Astronautics. beijing 100083. P. R. China Department of Applied Mathematics Beijing University of Aeronautics and Astronautics Beijing P. R. China

In this paper, we make a complete study of the unfolding of a quadratic integrable system with a homoclinic loop. Making a Poincare transformation and using some new techniques to estimate the number of zeros of Abelian integrals, we obtain the complete bifurcation diagram and all phase portraits of systems corresponding to different regions in the parameter space. In particular, we prove that two is the maximal number of limit cycles bifurcating from the system under quadratic non- conservative perturbations.

关键词： A quadratic integrable system A homoclinic loop Unfolding

The mathematical model of wetting angle of heterogeneous nucleation

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Science China(Technological Sciences) 2004年第4期47卷 391-397页

作者： HUANG Cheng1, SONG Bo1, MAO Jinghong2 & ZHAO Pei3.1. School of Metallurgical and Ecological Engineering, University of Science and Technology beijing, beijing 100083. China 2. School of Material Science, University of Science and Technology beijing, beijing 100083. China 3. Central Iron and Steel Research Institute, beijing 100081, China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Material Science University of Science and Technology Beijing

The heterogeneous nucleation has been analyzed in terms of the thermodynamic theory, and the mathematical model of wetting angle of heterogeneous nucleation has been developed based on the dynamic requirements of hetero- and homogeneous nucleation. With the wetting angel model, the wetting angles of different catalysts in liquid iron have been calculated. The result shows that the wetting angle of most catalysts is smaller than 40, and the value of f() is far less than 1. The wetting angles of TiN, TiC and RE2O3.are smaller, while the wetting angle of MnO is bigger among the ordinary nucleation catalysts. The wetting angles calculated by this model are in agreement with the results of other research work.

关键词： heterogeneous nucleation, mathematical model, wetting angle, undercooling.

Progress and review of the studies on the end-Triassic mass extinction event

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Science China Earth Sciences 2005年第12期48卷 2049-2060页

作者： DENG Shenghui1,2, LU Yuanzheng1,2,3.& XU Daoyi4 1. Research Institute of Petroleum Exploration and Development, beijing 100083. China 2. Key Laboratory of Oil and Gas Reservoir of PetroChina, beijing 100083. China 3. China University of Geosciences, beijing 100083. China 4. Institute of Geology, China Earthquake Administration, beijing 100029, China Research Institute of Petroleum Exploration and Development Beijing China Key Laboratory of Oil and Gas Reservoir of PetroChina Beijing China China University of Geosciences Beijing China Institute of Geology China Earthquake Administration Beijing China

The mass extinction at the end-Triassic is one of the five biggest in the Phanerozoic. However,it is the least well understood among these five events, and only till last decade it became a great academic interesting subject to geologists. The evidences for this event come obviously from bivalves, brachiopods, ammonites, corals, radiolaria, ostracods and foraminifera of marine habitats, and plants and tetrapods of terrestrial realm. By contrast, for some of other groups, such as marine gastropods and marine vertebrates, no mass extinction has been recog-nized yet. The extinction event is strongly marked at specific level but shown a complicated situa-tion at generic and family levels. Dramatic changing of the environment, such as the temperature raise due to the greenhouse effect, the marine anoxic habitats caused by a sudden transgression after the regression at the end of Triassic, has been claimed to be the main cause of the extinction. Many hypotheses have been suggested to demonstrate the mechanisms of the environment changing, among which two popular ones are the bolide impact and volcanic eruption. The Triassic-Jurassic (Tr-J) boundary mass extinction event is still poorly understood because no enough data have been obtained from the Tr-J boundary successional sections of both marine and terrestrial sediments, and most of these studies were regionally restricted. The basic aspects of the event and its associated environmental conditions remain poorly characterized and the causal mechanism or mechanisms are equivocal. Some authors even doubt its occurrence. China has many successionally developed terrestrial and marine Tr-J sections. Detailed studies of these sections may be important and significant for well understanding of the event.

关键词： progress, review, end-Triassic, mass extinction, mechanism, Tr-J boundary.

Effect of Preparation Condition on Low-density PS Particle Size and Distribution

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Journal of University of Science and Technology beijing 2001年第4期8卷 274-276页

作者： Huili Fan, Jiemin Liu, Meijuan Wen, Weixue Tian Applied Science School. University of Science and Technology beijing.beijing 100083. China Applied Science School University of Science and Technology Beijing Beijing 100083 China

The preparation conditions were studied in order to obtain smaller, narrow size-distributed and low-density polystyrene (PS) micro-particles by suspension polymerization. The results show that some of preparation conditions, the shape and position of stirrers, and stirring rate etc., have important influence on the size and distribution of particles. The preparation conditions must be carefully designed and controlled in order to obtain high-quality PS beads. A bow-shaped stirrer is helpful to produce small-sized particles and narrow size distribution, and the upper edge of a stirrer should be set to the same level as the surface of mixture, and the stirring rate should be controlled in the range of 520-600 r/min.

关键词： low-density micro-particles suspension polymerization preparation conditions

Local and non-local sources of airborne particulate pollution at beijing——The ratio of Mg/Al as an element tracer for estimating the contributions of mineral aerosols from outside beijing

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Science China Chemistry 2005年第3期48卷 253-264页

作者： HAN Lihui1, ZHUANG Guoshun1,2,3. SUN Yele1 & WANG Zifa3.1. The Center for Atmospheric Environmental Study, Department of Chemistry, beijing Normal University, beijing 100875, China 2. Center for Atmospheric Chemistry Study, Department of Environmental Science & Engineering, Fudan University, Shanghai 20043., China 3. LAPC/NZC, Institute of Atmospheric Physics, CAS, beijing 100029, China The Center for Atmospheric Environmental Study Department of Chemistry Beijing Normal University Beijing China Center for Atmospheric Chemistry Study Department of Environmental Science & Engineering Fudan University Shanghai China Institute of Atmospheric Physics CAS LAPC/NZC Beijing China

A new element tracer technique has firstly been established to estimate the contri-butions of mineral aerosols from both inside and outside beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in beijing, of which mineral aerosol accounted for 3.%―67% of total suspended particles （TSP）, 10%―70% of fine particles （PM2.5）, and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside beijing contributed 62% （3.%―86%） of the total mineral aerosols in TSP, 69% （52%―90%） in PM10, and 76% （59%―93.） in PM2.5 in spring, and 69% （52%―83.）, 79% （52%―93.）, and 45% （7%―79%） in TSP, PM10, and PM2.5, respectively, in winter, while only20% in summer and autumn. The sources from outside beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in beijing. The contributions from outside Bei-jing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.

关键词： mineral aerosol local sources non-local sources dust storm re-suspended dust element tracer technique.

Final Temperature Prediction Model of Molten Steel in RH-TOP Refining Process for IF Steel Production

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Journal of Iron and Steel Research International 2012年第3期19卷 1-5页

作者： WANG Yu-nan1, BAO Yan-ping1, CUI Heng2, CHEN Bin3. JI Chen-xi3.(1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology beijing, beijing 100083. China 2. Engineering Research Institute, University of Science and Technology beijing, beijing 100083. China 3. Shougang Research Institute of Technology, beijing 100041, China) State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing China Engineering Research Institute University of Science and Technology Beijing Beijing China Shougang Research Institute of Technology Beijing China

In order to precisely control the final temperature of molten steel in RH （Ruhrstahl Heraeus）-TOP blowing refining, the final temperature prediction models of molten steel in RH-TOP blowing refining process for Interstitial Free （IF） steel production were established under the condition of oxygen blowing and non-oxygen blowing respec- tively. The results show that the beginning molten steel temperature of refining and the amount of added scrap were influential factors, the baking temperature in vacuum chamber was a factor that had small influence. When the model was operated, the hitting probability was above 95%（under the condition of both oxygen blowing and non-oxygen blo- wing） of prediction deviation ±10℃. The accuracy is analyzed.

关键词： RH-TOP molten steel temperature prediction model

A New Method for Fractal Dimension Determination by STM at Nanometer Scale

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International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 64-68页

作者： Qikai Li Yue Zhang Wuyang Chu Chen Wang Chunli Bai (Applied Science School. University of Science and Technology beijing, beijing 100083. China)(Chemical Institute, Chinese Academy of Science, beijing 100080. China) Applied Science School University of Science and Technology Beijing Beijing 100083 China Chemical Institute Chinese Academy of Science Beijing 100080 China

A new method for determining the fractal dimension by STM at nanomeler scale has been ***- Mandelbrot fractal curves were used to verify the accuracy and reliability. The Computer simulation showed that fractal dimen- sion obtained with this method generally outran the traditional yard method. The new method has been applied to the fractal dimension determination of the fractures of Ti3.l and Ti-24Al-11Nb alloys. The results show that the fractal dimension of Ti-24Al-11Nb alloy is higher than that of Ti3.l, and it varies with the crark extending orientation.

关键词： fractal dimension STM nanometer scale Ti-Al alloy