检索结果-南通市图书馆

Multimedia Data Coding and its Development

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 229-232页

作者： Xingye Yu, 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

The requirements of data coding in multimedia applications are presented, the current technique of coding and relative standards is introduced, then the work that have been doing is presented, i.e. the wavelet-based coding method and the VE (Visual Entropy)-based coding method. The experiment results prove that these methods have gained a better perceptual quality of a reconstructed image and a lower bit rate. Their performance evaluations are better than JPEG (Joint Photographic Experts Group) coding. Finally, the future topics of study are put forward.

关键词： multimedia data coding MPEG (Moving Picture Experts Group) VE (Visual Entropy)

Improvement of Boxcar Integrator and Its Application to Low Resistance Measurement of Inductive Load Coil

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 180-184页

作者： Xisheng Li Shaochun Wang(Information engineering School, university of science and technology beijing, beijing 100083. china) Information engineering School University of Science and Technology Beijing Beijing 100083 China

A boxcar integrator is described which is suitable for the low-repetition-rate signal processing. This boxcar integrator, named fixed-interval mode boxcar integrator, is able to reject harmonics other than the first harmonic component. It can also decrease the effective time constant In many situations, the antialiasing filter with narrow bandwidth will cause distortion of the input signal. The fixed-interval mode boxcar integrator with suitable gate width can achieve relative high performance without signal distortion because the bandwidth of its antialiasing filter can be wider than that in the fixed-Point boxcar integrator. ms boxcar integrator is used as majn part of signalprocessing circult in the low resisance measurement of inductive load coil. The results of experiments show that the fixed-interval boxcar integrator is suitable for low-repetition-rate use.

关键词： signal processing resistance measurement boxcar integrator

Online application of automatic surface quality inspection system to finishing line of cold rolled strips

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2003年第4期10卷 38-41页

作者： Hao Sun, Ke Xu, and Jinwu XuNational engineering research Center of Advanced Rolling, university of science and technology beijing, beijing 100083. china National engineering research Center of Advanced Rolling. university of science and technology beijing Beijing 100083 China

An automatic surface quality inspection system installed on a finishing lineof cold rolled strips is introduced. The system is able to detect surface defects on cold rolledstrips, such as scratches, coil breaks, rusts, roll imprints, and so on. Multiple CCD area scancameras were equipped to capture images of strip surface simultaneously. Defects were detectedthrough 'Dark-field illumination' which is generated by LED illuminators. Parallel computationtechnique and fast processing algorithms were developed for real-time data processing. Theapplication to the production line shows that the system is able to detect defects effectively.

关键词： surface inspection cold rolled strip finishing line CCD cameras imageprocessing

Effects of silver powder particle size on the microstructure and properties of Ag-Yb_2O_3 electrical contact materials prepared by spark plasma sintering

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2010年第4期29卷 366-370页

作者： CHEN Xiaohua,JIA Chengchang,and LIU Xiangbing School of Materials science and engineering,university of science and technology beijing,beijing 100083.china School of Materials science and engineering University of Science and Technology Beijing Beijing China

mg-Yb203 electrical contact materials were fabricated by spark plasma sintefing （SPS）. The effects of silver powder particle size on the microstructure and properties of the samples were investigated. The surface morphologies of the sintered samples were examined by optical microscope （OM）, and the fracture morphologies were observed by scanning electron microscopy （SEM）. The physical and mechanical properties such as density, electrical resistivity, microhardness, and tensile strength were also tested. The results show that the silver powder particle size has evident effects on the sintered materials. Comparing with coarse silver powder （5 ktm）, homogeneous and fme microstmcture was obtained by fine silver powder （_〈0.5-1am）. At the same time, the electrical conductivity, microhardness, and tensile strength of the sin- tered samples with fine silver powder were higher than those of the samples with coarse silver powder. However, silver powder particle size has little influence on the relative densities, which of all samples （both by free and coarse silver powders） is more than 95%. The fracture characteristics are ductile.

关键词： composites electrical contact materials spark plasma sintering particle size microstructure physical properties mechanical properties

Optimization of Fractal Iterated Function System(IFS) with Probability and Fractal Image Generation

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2001年第2期8卷 152-156页

作者： Berthe Kya, Yang Yang (Information engineering School, university of science and technology beijing, beijing 100083. china) Univ Sci & Technol beijing Informat Engn Sch Beijing 100083 Peoples R China

There are several methods for rendering fractal images based on IFS (Iterated Function System) in computer graphic; but one concern of the computer graphic community has been the efficiency rendering algorithms. The invariant measures arising from IFSP (Iterate Function System with Probability) using the probabilistic algorithm are also known as chaos games. The role of these probabilities to generate the image of the attractor has been investigated using a multi-fractal analysis. The conventional choice of probability associated with each set /S/ to generate the attractor in least time possible is introduced, then a new method based on the self similarity and multi-fractal analysis is presented. The efficiency of the new method has been proved over the conventional method.

关键词： optimization of fractal IFS compression IFSP multi-fractal analysis

Molar heat capacities of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2007年第5期14卷 395-398页

作者： Baijun Yan, Jianhua Liu, Yunduo Dai, Qifeng Shu, and Zhihua Ren metallurgical and Ecological engineering School, university of science and technology beijing, beijing 100083. china [a]metallurgical Ecological engineering School university of science technology beijing beijing 100083 china

The molar heat capacities of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ were obtained using the differential scanning calorimetry (DSC) technique in a temperature range from 298 to 1473 K. The DSC curve of La2Mo2O9 showed an endothermal peak around 834 K corresponding to a first-order monoclinic-cubic phase transition, and the enthalpy change accompanying this phase transition is 5.99 kJ/mol. No evident endothermal peak existed in the DSC curve of La1.9Sr0.1Mo2O9-δ, but a broad thermal anomaly existed in its heat capacity curve at around 832 K. In addition, the heat capacity values of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ began to decrease at 1196 and 1330 K, respectively. The non-transitional heat capacity values of La2Mo2O9 and La1.9Sr0.1Mo2O9-δ were formulated using multiple regression analysis in two temperature ranges.

关键词： heat capacity phase transition La2Mo2O9 La1.9Sr0.1Mo2O9-δ DSC

Analysis on Microstructure and Misorientation of Ultrathin Hot Strip of Low Carbon Steel Produced by Compact Strip Production

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials science & technology 2002年第6期18卷 501-503页

作者： Hao YU, Yonglin KANG and Jie FUSchool of Materials science and engineering, university of science and technology beijing, beijing 100083. china Sch. of Mat. Sci. and Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The microstructure and misorientation of ultrathin hot strip were analyzed by CSP technology using electron back scattered diffraction (EBSD) method and Autoforge finite element program. The experimental results showed that the finishing hot rolling microstructures were the mixture of recrystallized and deformed austenite. After phase transformation, ferrite grains embody substructures and dislocations, leading to the high strength and relatively low elongation rate of the ultrathin hot strip. The FEM simulation of strain mode and distribution in deformation area has been fulfilled. The simulation results are in good agreement with the theoretical analysis and experimental results.

关键词： CSP Electron back scattered diffraction, Texture, Finite element method

Fractal Structure of the Core Loss Spectrum of Co-based Amorphous Soft Magnetic Alloy with Constant Permeability

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 54-56页

作者： Yiping Chen (Applied science School, university of science and technology beijing, beijing 100083. china) Applied science School University of Science and Technology Beijing Beijing 100083 China

In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range from 10 kHz to 200 kHz and at Bm = 0. 1 T,the P(f) has the fractal structure P (f) = Po, and with the increasing of induced anisotropy energy Ku, the fractal dimension Dfrises, thus the total power loss at high frequency increases and the frequency characteristic of P(f) becomes worse.

关键词： amorphous soft magnetic alloy constant permeability core loss fractal

Numerical prediction of the incremental melting and solidification process

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2003年第4期10卷 50-54页

作者： Jun Wang, Chengchang Jia, and Sheng YinMaterials science and engineering School, university of science and technology beijing, beijing 100083. china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

A mathematical formulation is applied to represent the phenomena in theincremental melting and solidification process (IMSP), and the temperature and electromagneticfields and the depth of steel liquid phase are calculated by a finite difference technique using thecontrol volume method. The result shows that the predicted values are in good agreement with theobservations. In accordance with the calculated values for different kinds of materials anddifferent size of molds, the technological parameter of the IMS process such as the power supply andthe descending speed rate can be determined.

关键词： incremental melting and solidification process (IMSP) numerical prediction electromagnetic field temperature field technological parameter