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Communication via Chaotic Synchronization Based on Contraction Maps

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Chinese Physics Letters 1996年第8期13卷 572-575页

作者： zhou chang-song CHEN Tian-lun Department of Physics Nankai UniversityTianjin 300071

A newly proposed method for constructing chaotically synchronizing systems is applied to *** independent information signals can be transmitted at the same time if the chaotic system is a multi-dimensional *** of the ... 详细信息

关键词： chaotic constructing method

Numerical investigations of focused wave interact with a moving cylinder

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Journal of Hydrodynamics 2023年第4期35卷 724-735页

作者： Yuan Zhuang Fu-chang zhou Wen-jun zhou De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Wuhan Second Ship Design and Research Institute Wuhan430205China Marine Design and Research Institute of China Shanghai200011China

This paper presents a numerical study on focused wave and current interactions with a *** cylinder is moving in the opposite direction to the wave *** effective computational decomposition method is adopted to reduce the calculation resources.A potential solver high-order spectral(HOS)method is applied to generate focused wave field,while our in-house computational fluid dynamics(CFD)solver naoe-FOAM-SJTU with overset grid takes the charge of achieving the viscous effect around the moving *** viscous domain moving with the cylinder thus the size and mesh grids in computational domain is greatly *** pressure on cylinder surface and wave fields around cylinder are compared with experimental data,shows a well ***,the scattering wave field and vortex shedding are *** the existence of moving cylinder,the classical scattering wave types are still observed.

关键词： Focused wave moving cylinder naoe-FOAM-SJTU solver computational decomposition method

Genetic Evolution Analysis on Wild Isolates of Citrus Tristeza Virus Originated in China Based on Coat Protein Genes Sequences

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Agricultural Sciences in China 2010年第11期9卷 1623-1629页

作者： YI Long zhou chang-yong zhou Yan LI Zhong-an Citrus Research Institute Southwest University~Citrus Research Institute Chinese Academy of Agricultural Sciences Chongqing 400712 P.R. China Jiangxi Navel Orange Engineering and Technology Research Center Gannan Normal University Ganzhou 341000 P.R.China

The coat protein （CP） genes were cloned and sequenced from viral particles of 11 isolates of citrus tristeza virus （CTV） collected from wild citrus plants in China and 4 Chinese isolates from cultivated sweet orange and pummelo varieties, respectively. By analyzing and comparing the nucleotide and amino acid sequences of CP genes, the 11 wild CTV isolates were found over 92% identical with 4 Chinese CTV isolates and 21 exotic CTV isolates from cultivated citrus. From 91 to 100% of the CTV CP gene sequences in wild type citrus plants were generally well conserved. Genetic evolution analysis indicated that the GC% of the CP gene was less than AT%, and more transition were found in the CP genes than transversion with the transition/transversion ratio ranging from 6.3 to 7.0 among species. The substitution frequency was the highest at the third codon, followed by the first and second codon. The ratio of non-synonymous mutations （du） to synonymous mutations （ds） was far lower than 1, suggesting that the CP gene might have experienced purifying selection in the evolution. Phylogenetic analysis revealed that the 11 CTV isolates in Chinese wild type citrus belonged to different phylogenetic clusters, and shared higher homology and closer relationships with other cultivated citrus CTV isolates from different countries, which indicated complicated genetic relationships among the CTV isolates. In addition, CTV isolates with similar biological characteristics usually located into the same clusters. Therefore, the conclusion was drawn that pathogenicity was critical to evolution and origin of CTV.

关键词： wild type citrus citrus tristeza virus sequence comparison phylogenetic evolution

Tripling Construction for Large Sets of Resolvable Directed Triple Systems

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Acta Mathematica Sinica,English Series 2006年第1期22卷 311-318页

作者： Jun Ling zhou Yan Xun chang Department of Mathematics Beijing Jiaotong University Beijing 100044 P. R. China

In this paper, we first define a doubly transitive resolvable idempotent quasigroup （DTRIQ）, and show that aDTRIQ of order v exists if and only ifv ≡0（mod3） and v ≠ 2（mod4）. Then we use DTRIQ to present a tripling construction for large sets of resolvable directed triple systems, which improves an earlier version of tripling construction by Kang （J. Combin. Designs, 4 （1996）, 301-321）. As an application, we obtain an LRDTS（4·3^n） for any integer n ≥ 1, which provides an infinite family of even orders.

关键词： Doubly transitive resolvable idempotent quasigroup Resolvable directed triple system,Large set Tripling construction

Dislocation density-me diate d creep ageing behavior of an Al-Cu-Li alloy

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Journal of Materials Science & Technology 2024年第7期174卷 204-217页

作者： chang zhou Lihua Zhan Chunhui Liu Minghui Huang College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China Light Alloys Research Institute Central South UniversityChangsha 410083China

Creep aging is well-known to be a time-dependent,coupled process of deformation and precipitation strengthening for age-hardening *** existing mechanisms are mainly attributed to those interac-tions between atomic diffusion and dislocation ***,an understanding of the relationship between dislocation density and a special multistage creep behavior,i.e.,double steady creep feature,is still far *** we investigate the effect of various dislocation density levels on such an abnormal multistage creep of an Al-Cu-Li *** find that the increased dislocation densities enable an apparent time decrease(from 6.2 h to 0.8 h)of their first steadyⅡ-*** yield strength of post-aged sam-ples increases from 425.0 MPa to 580.0 MPa while the corresponding elongation decreases from 12.3%to 7.3%for the creep-aged samples#1 to#*** results also reveal that a great difference in dislocation configuration,tailored by various density levels,results in varying creep processes of theⅡ-*** stage is closely related to the nucleation and early growth of T_(1)*** number densities(maximum:2.9×10^(19)m^(-3))and the average length(maximum:21.3 nm)of T_(1)precipitates are much smaller than those of the stable peak-aged T_(1)phases,suggesting that creepⅡ-stage of all three creep-aged samples is dominant by the nucleation and initial growth of those T_(1)*** study provides valuable insights into the dislocation density-mediated creep deformation of an Al-Cu-Li alloy.

关键词： Dislocation density Al-Cu-Li alloy Creep ageing T_(1)precipitation

Mechanism of Embrittlement and De-Embrittlement for 2.25Cr-1Mo Steel

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Journal of Iron and Steel Research International 2011年第3期18卷 47-51页

作者： ZHANG Xi-liang zhou chang-yu School of Mechanical and Power Engineering Nanjing University of TechnologyNanjing 210009JiangsuChina

The constant embrittlement curve for constant segregation concentration on grain boundary of impurity element P and relationship between equilibrium grain boundary segregation concentration and operation time for 2.25Cr-1Mo steel were derived based on the theory of equilibrium grain boundary *** mechanism of step-cooling test and mechanism of de-embrittlement for 2.25Cr-1Mo steel were *** segregation rate will increase but equilibrium grain boundary segregation concentration of impurity element P will decrease as temperature increases in the range of temper embrittlement *** is one critical temperature of embrittlement corresponding to each embrittlement *** the further heat treating temperature is higher than critical temperature,the heat treating will become a de-embrittlement process;otherwise,it will be an embrittlement *** critical temperature of embrittlement will shift to the direction of low temperature as further *** a result,some stages of step-cooling test would change into a de-embrittlement *** grain boundary desegregation function of impurity element P was deduced based on the theory of element diffusion,and the theoretical calculation and experimental results show that the further embrittlement or de-embrittlement mechanism can be interpreted qualitatively and quantitatively by combining the theory of equilibrium grain boundary segregation with constant embrittlement curve.

关键词： step-cooling test critical embrittlement temperature embrittlement mechanism grain boundary desegregation

Transmitting Multiple Information Signals by a Single Chaotic Carrier

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Chinese Physics Letters 1997年第3期14卷 161-164页

作者： zhou chang-song CHEN Tian-lun Department of Physics Nankai UniversityTianjin 300071

A method for transmitting multiple digital information signals by a single transmitted chaotic signal is *** information signals are encoded by modifying some tunable parameters of a chaotic system and decoded at the receiver by following the parameter modulation in the transmitter via *** Lorenz system is used to demonstrate the validity,robastness and security of the method.

关键词： method chaotic system

Combined effects of polymer SH and ryegrass on the water-holding characteristics of loess

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Journal of Arid Land 2024年第12期16卷 1686-1700页

作者： YING Chunye LI Chenglong LI Lanxing zhou chang School of Geological Engineering Qinghai UniversityXining 810016China Petroleum Engineering Technology Research Institute of Shengli Oilfield SINOPECDongying 257000China Army Engineering University of PLA Xuzhou 221000China School of Resources and Geosciences China University of Mining and TechnologyXuzhou 221116China

The Chinese Loess Plateau has long been plagued by severe soil erosion and water *** this study,we proposed a technique involving the combined use of polymer SH and ryegrass and evaluated its effectiveness in modifying the water-holding characteristics of loess on the Chinese Loess Plateau(Chinese loess).We analysed the volumetric water content and water potential of untreated loess,treated loess with single polymer SH,treated loess with single ryegrass,and treated loess with both polymer SH and ryegrass using the loess samples collected from the Chinese Loess Plateau in July ***,fractal theory was used to analyse the fractal characteristics of the soil structure,and wet disintegration tests were conducted to assess the structural stability of both untreated and treated loess *** results showed that the loess samples treated with both polymer SH and ryegrass presented much higher volumetric water content and water potential than the untreated loess samples and those treated only with ryegrass or polymer ***,the planting density of ryegrass affected the combined technique,since a relatively low planting density(20 g/m2)was conducive to enhancing the water-holding capacity of Chinese *** fractal dimension was directly correlated with both volumetric water content and water potential of Chinese ***,since loess treated with both polymer SH and ryegrass was more saturated with moisture,its water potential increased,thus improving its water-holding capacity and fractal *** combined technique better resisted disintegration than ryegrass alone but had slightly less resistance than polymer SH *** study provides insight into soil reinforcement and soil water management using polymetric materials and vegetation on the Chinese Loess Plateau.

关键词： loess ryegrass polymer SH water-holding characteristics fractal theory Chinese Loess Plateau

Active compliance and force estimation of a continuum surgical manipulator based on the tip-pose feedback

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Science China(Technological Sciences) 2023年第9期66卷 2517-2529页

作者： WU BaiBo zhou chang WANG Xiang SUN DaWei XU Kai School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Gynaecology and Obstetrics Peking Union Medical College HospitalBeijing 100730China

Continuum manipulators have been applied in different surgical scenarios due to their dexterity and multi-DoF(degree of freedom)design *** improve surgery safety,it is preferable to enable active compliance and force sensing abilities for a continuum *** works on active compliance and force sensing often rely on force sensors at the proximal or the distal ends,which inevitably increases the system *** this paper,a shape reconstruction algorithm,a compliant motion controller,and a force estimation method are proposed successively based on the manipulator's tip pose via visual *** support vector regression(SVR)trainers are constructed and trained to compensate for the actuation residues,which are the differences between the actual actuation lengths outputs at the actuators and the ideal actuation lengths calculated from the estimated shape using the kinematics model,under no-load ***,a compliant motion controller and a force estimation method are realized based on the current actuation residues,compared with the actuation residues under the no-load *** this way,no additional sensors are needed as an endoscopic camera is often available in a laparoscopic or endoscopic surgical *** experiments were conducted on aφ3 mm-continuum manipulator to demonstrate the effectiveness of the proposed algorithms.

关键词： continuum manipulator vision feedback shape reconstruction compliant motion control force estimation