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Ferroelectric properties of Bi_(3.4)Ho_(0.6)Ti_3O_(1.0} thin films prepared by sol-gel method

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Science china(Technological Sciences) 2008年第9期51卷 1439-1444页

作者： fu ChengJu1. HUANG Zhi{1., LI Jie2.& GUO DongYun3 1.{2. of Materials Science and Technology, wuhan university of Technology, wuhan 430070, china 2.{2. of Mechanical Engineering, Chongqing university of Science and Technology, Chongqing 400050, china 3 Department of Physics, wuhan university, wuhan 430072. china school of Materials Science and Technology Wuhan University of Technology Wuhan 430070 China school of Mechanical Engineering Chongqing University of Science and Technology Chongqing 400050 China Department of Physics Wuhan University Wuhan 430072 China

We have prepared the Ho-substituted bismuth titanate (Bi3.4Ho0.6Ti3O1.0} BHT) thin films on Pt/Ti/SiO2.Si substrates using sol-gel method. The crystal structure and morphology of the films were characterized using X-ray diffraction and atomic force microscopy. The BHT film shows a single phase of Bi-layered Aurivillius structure and dense microstructure. The 2.r and 2.c of the 600-nm-thick BHT film were 38.4 μC/cm2.and 376.1.kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about 31. and 0.01. at a frequency of 1.MHz, respectively. The Pr value decreased to 93% of its pre-fatigue values after 4.46×1.9 switching cycles at 1.MHz frenquency, and the BHT film shows good in-sulating behavior according to the test of leakage current.

关键词： Bi3.4Ho0.6Ti3O1. thin film sol-gel method ferroelectric property fatigue dielectric constant

Advanced Design of Soft Robots with Artificial Intelligence

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Nano-Micro Letters 2024年第10期16卷 474-521页

作者： Ying Cao Bingang xu Bin Li Hong {1. Nanotechnology Center School of Fashion and TextilesThe Hong Kong Polytechnic UniversityHong Kong 999077People's Republic of China Department of Mathematics and Information Technology The Education University of Hong KongHong Kong 999077People's Republic of China Bioinspired Engineering and Biomechanics Center Xi'an Jiaotong UniversityXi'an 710049People's Republic of China

In recent years,breakthrough has been made in the field of artificial intelligence(AI),which has also revolutionized the industry of *** robots featured with high-level safety,less weight,lower power consumption have always been one of the research ***,multifunctional sensors for perception of soft robotics have been rapidly developed,while more algorithms and models of machine learning with high accuracy have been optimized and *** of soft robots with AI have also been advanced ranging from multimodal sensing,human-machine interaction to effective actuation in robotic ***-less,comprehensive reviews concerning the new developments and strategies for the ingenious design of the soft robotic systems equipped with AI are ***,the new development is systematically reviewed in the field of soft robots with ***,background and mechanisms of soft robotic systems are briefed,after which development focused on how to endow the soft robots with AI,including the aspects of feeling,thought and reaction,is ***,applications of soft robots with AI are systematically summarized and discussed together with advanced strategies proposed for performance *** thoughts for future intelligent soft robotics are pointed ***,some perspectives are put forward.

关键词： Soft robotic systems Artificial intelligence Design tactics Review and perspective

On the new results of global attractive set and positive invariant set of the Lorenz chaotic system and the applications to chaos control and synchronization

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Science in china(Series F) 2005年第3期48卷 304-321页

作者： LIAO Xiaoxin 1, 2. 3 , fu Yuli 4 & XIE Shengli 4 1. Department of Control Science & Control Engineering, Huazhong university of Science & Technology, {2. 430074, china 2. school of Automation, wuhan university of Science & Technology, {2. 430070, china 3. school of Information, Central South university of Economy, Politics and law, {2. 430064, china 4. school of Electronics & Information Engineering, South china university of Technology, Guangzhou 510640, china Correspondence should be addressed to Liao Xiaoxin (email: xiaoxin_liao@***) 1. Department of Control Science & Control Engineering Huazhong University of Science & Technology 430074 Wuhan China 2. {1. of Automation Wuhan University of Science & Technology 430070 Wuhan China 3. school of Information Central South University of Economy Politics and Law 430064 Wuhan China 4. school of Electronics & Information Engineering South China University of Technology 510640 Guangzhou China

Constructing a family of generalized Lyapunov functions, a new method is proposed to obtain new global attractive set and positive invariant set of the Lorenz chaotic system. The method we proposed greatly simplifies the complex proofs of the two famous estimations presented by the Russian scholar Leonov. Our uniform formula can derive a series of the new estimations. Employing the idea of intersection in set theory, we extract a new Leonov formula-like estimation from the family of the estimations. With our method and the new estimation, one can confirm that there are no equilibrium, periodic solutions, almost periodic motions, wandering motions or other chaotic attractors outside the global attractive set. The Lorenz butterfly-like singular attractors are located in the global attractive set only. This result is applied to the chaos control and chaos synchronization. Some feedback control {1.s are obtained to guarantee that all the trajectories of the Lorenz systems track a periodic solution, or globally stabilize an unstable (or locally stable but not globally asymptotically stable) equilibrium. further, some new global exponential chaos synchronization results are presented. Our new method and the new results are expected to be applied in real secure communication systems.

关键词： Lorenz chaotic system global attractive set positive invariant set globally exponential tracking globally exponential synchronization.

Experimental study and correlation development for the two-phase frictional pressure drop of flow boiling in copper foam fin microchannels

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Science china(Technological Sciences) 2024年第9期67卷 2758-2776页

作者： fu Kai {1. XiangHua LIANG XinGang school of Aerospace Engineering Tsinghua UniversityBeijing 100084China

Flow boiling in microchannels with porous walls has received extensive attention in recent years. Compared with the emphasis on heat transfer, there is a lack of research on the effect of the porous wall structures on the pressure drop characteristics. In this study, systematic experiments are performed to measure the pressure drop of water-vapor two-phase flow in five microchannels with copper foam fins, which consist of nine or six channels and fins of copper foam. The porosities of the foam fins range from0.78 to 0.82.and ratios of fin width to channel width range from 0.5 to 2. The channels are approximately 0.5 or 1.mm in width and 1.mm in height. Both adiabatic and flow boiling experiments are conducted with water at mass fluxes ranging from 66 to 407 kg/(m^(2.s). In the adiabatic experiments, the average quality in channels is between 0.01. and 0.846. In the flow boiling experiments, the outlet quality of channels is between 0.040 and 0.863. Slug flow, churn flow, annular flow, and wispy-annular flow are observed in adiabatic experiments. A two-phase frictional pressure drop correlation based on the Lockhart-Martinelli model is developed for copper foam fin microchannels by introducing the effects of the mass flux, porosity, ratio of fin width to channel width, and heating condition step by step. The mean absolute percentage errors of the new correlation are 7.53% for 32.data points under adiabatic conditions and 5.51. for 2.8 data points under flow boiling conditions, respectively. This work provides insight into the correlations of frictional pressure drop in microchannels with porous walls.

关键词： two-phase flow boiling pressure drop correlation microchannel copper foam porous wall

Parentage determination of an isolated Yangtze finless porpoise population Neophocaena phocaenoides asiaeorientalis in the Yangtze Tian-e-Zhou Baiji National Natural Reserve based on molecular data

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Progress in Natural Science:Materials International 2005年第2期15卷 54-61页

作者： XIA Junhong 1.2. ZHENG Jinsong 1.2. xu Limei 1.2.and WANG Ding1.(1. Institute of Hydrobiology, Chinese Academy of Sciences, wuhan 430072. china 2. Graduate {2. of the Chinese Academy of Sciences, Beijing 1.0039, china) Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China. Graduate school of the Chinese Academy of Sciences Beijing 100039 China

Reproductive behaviors are poorly known for the Yangtze finless porpoise Neophocaena phocaenoides asiaeorientalis. In this study, the parentage of an isolated Yangtze finless porpoise population inhabiting the Yangtze Tian-e-Zhou Baiji National Natural Reserve is determined by analysis of microsatellite loci and mitochondrial DNA (mtDNA) control region sequences, and the porpoise's reproductive behaviors are studied. Overall 4 full parentage assignments and additional 3 single parentage assignments were determined for the population of {1. individuals. The analysis shows that their estimated reproductive cycle is shorter than that reported previously and there probably exists an overlapping between gestation and lactation period. The study also shows that the female does not show fidelity to a particular male for breeding and vice versa, the oldest males did not monopolize mating and the dominance rank could not be so strict for the porpoise society. Moreover, the porpoise's mating pattern and relatedness among candidate parents are discussed here. These results provide important information for making guidelines of management and conservation for this protected population.

关键词： Yangtze finless porpoise isolated population reproductive behavior parentage

Microstructure and Fractural Morphology of Cobalt-based Alloy Laser Cladding

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Journal of wuhan university of Technology(Materials Science) 2003年第3期18卷 30-32页

作者：陈浩 school of Materials Science and Engineering Wuhan Univercity of Technology

The solidification features,micro segregation,and fracture characteristics of cobalt based alloy on the substrate of 2.CrMo steel by laser cladding were studied by using electron *** results show that the fine columnar grains and cellular dendrite grains are obtained which are perpendicular to the coating/substrate interface;the primary arms are straight while the side branches are degenerated;the microstructure consists of primary face centered cubic (fcc) Co dendrites and a network of Cr enriched eutectic M2.C6 (M=Cr,W,Fe) carbides;the micro segregation is severe for the rapid heating and cooling of laser cladding;the typical brittle intergranular fracture occurs in cobalt based laser cladding layer.

关键词： laser cladding Cobalt based alloy solidification microstructure micro segregation fracture

Effects of diamond particle size on microstructure and properties of diamond/Al-1.0}i composites prepared by vacuum-assisted pressure infiltration

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china Foundry 2024年第4期21卷 360-368页

作者： Jia-ping fu Can-{1. Zhou Guo-fa Mi Yuan Liu school of Materials Science and Engineering Henan Polytechnic UniversityJiaozuo 454100HenanChina school of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

Diamond/aluminium composites have attracted attention in the field of thermal management of electronic packaging for their excellent *** order to solve the interfacial problem between diamond and aluminium,a novel process combining pressure infiltration with vacuum-assisted technology was proposed to prepare diamond/aluminum *** effect of diamond particle size on the microstructure and properties of the diamond/Al-1.0}i composites was *** results show that the diamond/Al-1.0}i composites exhibit high relative density and a uniform *** thermal conductivity and coefficient of thermal expansion increase with increasing particle size,while the bending strength exhibits the opposite *** the average diamond particle size increases from 45μm to 42.μm,the thermal conductivity of the composites increases from 455 W·m^(-1.·K^(-1.to 71. W·m^(-1.·K^(-1.and the coefficient of thermal expansion increases from 4.97×1.^(-6)K^(-1.to 6.72.1.^(-6)K^(-1.,while the bending strength decreases from 353 MPa to 2.6 *** research demonstrates that high-quality composites can be prepared by the vacuum-assisted pressure infiltration process and the thermal conductivity of the composites can be effectively improved by increasing the diamond particle size.

关键词： diamond/aluminum composites thermal conductivity electronic packaging vacuum-assisted pressure infiltration

Performance Characterization of CR/PU Asphalt for Potential Application in Assembled Fast-Repairing Engineering

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Fluid Dynamics & Materials Processing 2024年第5期20卷 1063-1074页

作者： Hong Pang Ao Lu Ming xiong Chen Chen Xian Cao xiong xu Jing Wang hubei Regional Management Headquarters CCCC Asset Management Co.Ltd.Beijing101399China school of Civil Engineering and Architecture Wuhan Institute of TechnologyWuhan430073China hubei Provincial Engineering Research Center for Green Civil Engineering Materials and Structures Wuhan Institute of TechnologyWuhan430073China

Conventional repairing methods for asphalt pavement have some inconveniences,such as insufficient strength,and are typically *** address these issues,this study proposes a new technological method to design and prepare a high-performance assembled asphalt concrete block for fast repair of the potholes.A series of composite modified asphalt binders with 1.%crumb rubber(CR)and different dosages(0%,1.,3%,5%)of polyurethane(PU)are examined to determine the optimized ***,the corresponding asphalt mixtures are prepared for further comparison and assessment of engineering properties,such as moistureinduced damage,high-temperature deformation,and low-temperature cracking *** test results show that PU can significantly improve the high-temperature performance and hardness of(crumb rubber modified asphalt)CRMA binder;3%PU contributes allowing the resistance of CRMA mixture to moisture-induced damage at higher levels,particularly under water whole immersion;as 3%PU is added,the high-temperature rutting deformation resistance of the CRMA mixture increases significantly,and the low-temperature anti-cracking properties are also improved ***,the innovatively designed high-quality assembled fast-repairing asphalt concrete block is recommended as an appropriate option for highway maintenance.

关键词： Composite modified asphalt crumb rubber polyurethane assembled fast-repairing asphalt concrete maintenance engineering

Significant annealing-induced hardening effect in nanolaminate d-nanotwinne d(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8)me dium-entropy alloy by severe cold rolling

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Journal of Materials Science & Technology 2024年第3期170卷 156-166页

作者： Shuqing Yuan Hui fu Lei Qian Chi Fai Cheung {1.-Sheng Yang State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Hong Kong Polytechnic university Shenzhen Research Institute Shenzhen 518060China

Due to the easy coarsening caused by poor thermal stability,the verified annealing-induced hardening in nanograined metals can only maintain at a relatively low-temperature *** this study,a nanolam-inated(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8)medium-entropy alloy with an average lamellae thickness of∼2. nm embedded by thinner nanotwins was fabricated by severe cold rolling to achieve superior thermal *** with the conventional nanotwinned CrCoNi with nanotwins inside ultra-fined grains,the hier-archical nanolaminated-nanotwinned(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8) exhibits a significant annealing-induced hard-ening effect,i.e.,hardness increasing from∼2.0 HV in the original specimen to∼500 HV in the cold-rolled status and finally∼630 HV after annealing at 600℃for 1.*** microstructure characterizations reveal that the reduced dislocation density and formation of L1.(2.ordered domain are mainly responsible for such hardening effect,which is facilitated by the effectively suppressed coarsening with annealing temperature,i.e.,slow detwinning process and well-retained low-angle nanolamellar *** coarsening mechanisms from the cold-rolled nanolamellae to the fully recrystallized micro-equiaxed structures under the annealing temperatures ranging from 400 to 800℃ were also elucidated by atomic observations.

关键词： Annealing-induced hardening Thermal stability Nanolaminated-nanotwinned structure CrCoNi Detwinning Grain boundary migration