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Centroid-based semi-fragile audio watermarking in hybrid domain

Science China(Information Sciences) 2010年第3期53卷 619-633页

作者： WANG HongXia & FAN MingQuan school of Information Science and Technology, southwest jiaotong university, {2., China 1. school of Information Science and Technology Southwest Jiaotong University Chengdu 610031 China

Many previous (semi-) fragile audio watermarking schemes adopt binary images as watermarks, which reduce the security of watermarking systems. On the other hand, the content-based or feature-based second generation digital watermarking has limited applicability, and its partial feature points may be damaged by watermarking operations and various common signal processing. To overcome these problems, in this paper, a novel centroid-based semi-fragile audio watermarking scheme in hybrid domain is proposed. The theoretical lower limit of signal to noise ratio (SNR) for objective evaluation of the imperceptibility of watermarked audio signal is deduced, and the watermark embedding capacity and the tamper detection ability are theoretically analyzed. In the proposed scheme, first, the centroid of each audio frame is computed, then Hash function is performed on the obtained centroid to get the watermark, after that, the audio sub-band which carries centroid of audio frame is performed with discrete wavelet transform (DWT) and discrete cosine transform (DCT), and finally the encrypted watermark bits are embedded into the hybrid domain. Theoretical analysis and experimental results show that the proposed scheme is inaudible and applicable to different types of audio signals. Furthermore, its ability of tamper detection and tolerance against common signal processing operations are excellent. Comparing with the existing schemes, the proposed scheme can effectively authenticate the veracity and integrity of audio content, and greatly expand the applicability of the content-based audio watermarking scheme.

关键词： semi-fragile audio watermarking centroid inaudibility tamper detection

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Experimental Study of Tunnel Fire with Natural Ventilation

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湖南大学学报（自然科学版） 2009年第S1期36卷 23-25页

作者： YUAN Zhong-yuan,LEI Bo,CHEN Peng-yun(school of Mechanical Engineering,southwest jiaotong university,{2.,Sichuan 61003.,China) school of Mechanical Engineering Southwest Jiaotong University Chengdu 610031 China

The 1/15 reduced-scale experiments using Froude scaling were designed to study the effect on the smoke control efficiency for subway tunnel fires with natural ventilation *** propane gas fires with heat release rate 11.48 kW was used,which corresponds to the heat release rate 10 MW in the full-scale *** temperature distributions under the ceiling were measured by K-type thermocouples to investigate smoke movement,and the velocity of smoke in shafts was measured by hot-wire anemometer to obtain the smoke extract amount of ventilation *** results show that the smoke temperature under the ceiling varies with the longitudinal different distance from fire *** results also show that the smoke temperature distributions and the smoke control efficiency in tunnel vary with the space between ventilation shafts and vary with the area and the height of ventilation shaft.

关键词： natural ventilation mode metro tunnel fire reduced-scale experiments froude scaling

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Strengths and Fracture Mechanisms of Al_2._3 Short Fiber Reinforced Al-Mg Alloy Matrix Composite at Elevated Temperatures

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Journal of Materials Science & Technology 2002年第3期18卷 257-260页

作者： Guozheng KANGDepartment of Applied Mechanics and Engineering, southwest jiaotong university, chengdu 61003., ChinaChuan YANG and Jixi ZHANGDepartment of Materials Engineering, southwest jiaotong university, chengdu 61003., China [ Manuscript received Janu SW jiaotong Univ Dept Appl Mech & Engn Chengdu 610031 Peoples R China SW jiaotong Univ Dept Mat Engn Chengdu 610031 Peoples R China

Using the experimental and theoretical methods, the tensile strengths and fracture mechanisms of AI2.3 short fiber reinforced AI-Mg alloy matrix composite at elevated temperatures were researched. The interfacial microstructural characteristics and the fracture surfaces of the composite at different temperatures were observed by transmission electron microscope (TEM) and by scanning electron microscope (SEM), respectively. Then, from the results of microscopic observation, the fracture mechanisms of the composite at different temperatures are discussed. Finally, the tensile strengths of the composite at elevated temperatures were predicted by statistical integration average (SIA) method with the consideration of various fracture mechanisms. It was shown that the strengths and fracture mechanisms of the composite at elevated temperature (300℃) were significantly different from those at room temperature due to the variations of interfacial bonding states. The tensile strengths predicted by the SIA method at elevated temperatures agreed well with the experimental results.

关键词： Fracture A12.3 Al-Mg alloy Composite

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The influence of impurity on the critical thickness of the CeO_2.buffer layer for coated conductors

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Science China(Physics,Mechanics & Astronomy) 2009年第7期52卷 993-996页

作者： PAN Min1, HUANG Zheng2. MA HuanFeng2. QIANG WeiRong2. WEI LianFu1, WANG Long2.& ZHAO Yong1,3 1 Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R&D Center (SRDC), southwest jiaotong university, chengdu 61003., China 2.{2. of Physical Science and Technology, southwest jiaotong university, chengdu 61003., China 3 Superconductivity Research Group, {2. of Materials Science and Engineering, university of New South Wale, Sydney, 2.52.NSW, Australia Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China) Superconductivity R&D Center (SRDC) Southwest Jiaotong University Chengdu 610031 China school of Physical Science and Technology Southwest Jiaotong University Chengdu 610031 China Superconductivity Research Group School of Materials Science and Engineering University of New South Wale Sydney 2052 NSW Australia

The lattice parameters, band structure, density of state and elastic constant of RE-doped CeO2.(RE=Sm, Gd, Dy), the buffer material for coated HTS conductors, are calculated using the plane-wave method with pseudopotentials based on the density functional theory (DFT) of first-principle. The rule and mechanism of the effect of rare earth impurity on the critical thickness of the CeO2.buffer layer are investigated. It is found that, in the range of the calculation, the changes of the lattice volume V and elastic constant E of CeO2.with the impurity are mainly determined by the increased electrons ne of the system. The relationship of the elastic constant E and increased electrons ne is established. It is indicated that the critical thickness of the CeO2.single buffer layer doped with Sm, Gd, and Dy may be enhanced by 2.%, 43% and 33%, respectively.

关键词： CeO2 first principle critical thickness elastic constants

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Range inclusion of operators on non-archimedean Banach space

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Science China mathematics 2010年第12期53卷 3215-3224页

作者： WANG PengHui 1 & ZHANG Xu 2.3 1 school of mathematics, Shandong {2., Jinan 2.0100, China 2.Key Laboratory of Systems and Control, Academy of mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China 3.school of mathematics, Sichuan {2., chengdu 610064, China 1. school of mathematics Shandong University Jinan 250100 China2. Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China3. School of Mathematics Sichuan University Chengdu 610064 China

In this paper, we establish some range inclusion theorems for non-archimedean Banach spaces over general valued fields. These theorems provide close relationship among range inclusion, majorization and factorization for bounded linear operators. It is found that these results depend strongly on a continuous extension property, which is always true in the classical archimedean case, but may fail to hold for the non-archimedean setting. Several counterexamples are given to show that our results are sharp in some sense.

关键词： range inclusion majorization factorization non-archimedean Banach space continuous extension property

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IMPROVED HOMOTOPY ITERATION METHOD AND APPLIED TO THE NINE-POINT PATH SYNTHESIS PROBLEM FOR FOUR-BAR LINKAGES

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Chinese Journal of Mechanical Engineering 2000年第1期13卷 10-16页

作者： Zhang Jian Chen Yong (school of Mechanical Engineering, southwest jiaotong university) 西南交通大学四川成都

A new algorithm called homotopy iteration method based on the homotopy function is studied and improved. By the improved homotopy iteration method, Polynomial systems with high Order and deficient can be solved fast and efficiently comparing to the original homotopy iteration method. Numerical examples for the ninepoint path synthesis of four-bar linkages show the advantages and efficiency of the improved homotopy iteration method.

关键词： Homotopy function Homotopy iteration method Nine-point path synthesis Four-bar linkage

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MOTION TYPES AND CHAOS OF MULTI-BODY SYSTEMS VIBRATING WITH IMPACTS

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Acta Mechanica Sinica 1991年第4期7卷 369-375页

作者： Shu Zhongzhou southwest jiaotong university,chengdu 61003.,China 1. southwest jiaotong university 610031 Chengdu China

In this paper,the limit sets theory for an autonomous dynamical system is generalized to a multi-body system vibrating with *** discover that if every motion of the system is bounded,it has only four different types:periodic motion 7 t,non-periodic recurrent motion γ2.and non-Poisson stable mo- tions γ3 and γ4 approaching γ1 and γ2. respectively.γ2.is the source of *** is very interesting that cha- otic motions seem stochastic but possess the character of *** way of example,we discuss chaotic motions of a small ball bouncing vertically on a massive vibrating *** result obtained by us is different from that obtained by Holmes.

关键词： multi-body impact vibrations recurrent motion chaos

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The study of adsorption gas sensor based carbon nanotube film

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Science China(Technological Sciences) 2005年第4期48卷 372-384页

作者： LI Xin1, LIU Junhua2.& ZHU Changchun1 1. school of Electronic and Information Engineering, Xi’an jiaotong {2., Xi’an 710049, China 2. school of Electric Engineering, Xi’an jiaotong {2., Xi’an 710049, China 1. school of Electronic and Information Engineering Xi’an Jiaotong University 710049 Xi’an China 2. school of Electric Engineering Xi’an Jiaotong University 710049 Xi’an China

The study of gas sensitivity of multi-wall carbon nanotubes (MWNTs), which is deposited by low press chemical vapor deposition (LPCVD), is presented. The results show that the pure MWNTs are not sensitive to the gases measured, while the composite film consisting of the MWNTs and silicon dioxide is sensitive to the methane, the hydrogen and the acetylene. The MWNTs and silicon dioxide composite film have the capacitance characteristic because of the formation of Schottky junctions within the MWNTs. The chemistry adsorption of the gas measured on the surface of the MWNTs affects the space discharge area of the Schottky junction, so that the dielectric constant changes with the gas concentration. That is why the gas is sensed.

关键词： gas sensor, carbon nanotubes, low press chemical vapor deposition, scatter.

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Constructing globally consecutive 3D conductive network using P-doped biochar cotton fiber for superior performance of silicon-based anodes

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Journal of Materials Science & Technology 2024年第6期173卷 181-191页

作者： Jun Cao Jianhong Gao Kun Wang Zhuoying Wu Xinxin Zhu Han Li Min Ling chengdu Liang Jun Chen Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China Institute of Zhejiang university-Quzhou Zheda Road 99Quzhou 324000China

The inferior conductivity and drastic volume expansion of silicon still remain the bottleneck in achieving high energy density Lithium-ion Batteries(LIBs).The design of the three-dimensional structure of electrodes by compositing silicon and carbon materials has been employed to tackle the above challenges,however,the exorbitant costs and the uncertainty of the conductive structure persist,leaving ample room for ***,silicon nanoparticles were innovatively composited with eco-friendly biochar sourced from cotton to fabricate a 3D globally consecutive conductive *** network serves a dual purpose:enhancing overall electrode conductivity and serving as a scaffold to maintain electrode *** conductivity of the network was further augmented by introducing P-doping at the optimum doping temperature of 350℃.Unlike the local conductive sites formed by the mere mixing of silicon and conductive agents,the consecutive network can affirm the improvement of the conductivity at a macro ***,first-principle calculations further validated that the rapid diffusion of Li^(+)is attributed to the tailored electronic microstructure and charge rearrangement of the *** prepared consecutive conductive Si@P-doped carbonized cotton fiber anode outperforms the inconsecutive Si@Graphite anode in both cycling performance(capacity retention of 1777.15 mAh g^(-1) vs.682.56 mAh g^(-1) after 150 cycles at 0.3 C)and rate performance(12.4.2. mAh g^(-1) vs.370.2. mAh g^(-1) at 2.0 C).The findings of this study may open up new avenues for the development of globally interconnected conductive networks in Si-based anodes,thereby enabling the fabrication of high-performance LIBs.

关键词： 3D conductive network Biochar carbon-silicon anode Heteroatoms doping strategy DFT calculation Lithium-ion battery

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Theory of truth degrees of propositions in the logic system Ln^＊

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Science in China(Series F) 2006年第4期49卷 471-483页

作者： LI Jun1,2.& WANG Guojun1,3 1. Institute of mathematics, Shaanxi Normal university, Xi’an 710062. China 2. {2. of Sciences, Lanzhou university of Technology, Lanzhou 730050, China 3. Research Center for Science, Xi’an jiaotong university, Xi’an 710049, China 1. Institute of mathematics Shaanxi Normal University Xi’an 710062 China 2. school of Sciences Lanzhou University of Technology Lanzhou 730050 China 3. Research Center for Science Xi’an Jiaotong University Xi’an 710049 China

By means of infinite product of uniformly distributed probability spaces of cardinal n the concept of truth degrees of propositions in the n-valued generalized Lu- kasiewicz propositional logic system Ln^＊ is introduced in the present paper. It is proved that the set consisting of truth degrees of all formulas is dense in [0,1], and a general expres- sion of truth degrees of formulas as well as a deduction rule of truth degrees is then obtained. Moreover, similarity degrees among formulas are proposed and a pseudo-metric is defined therefrom on the set of formulas, and hence a possible framework suitable for developing approximate reasoning theory in n-valued generalized Lukasiewicz propositional logic is established.

关键词： truth degree similarity degree approximate reasoning.

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