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Comparison of the very high cycle fatigue behaviors of INCONEL 718 with different loading frequencies

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Science China(Physics,Mechanics & Astronomy) 2013年第3期Mechanics & Astronomy) .卷 617-623页

作者： ZHANG YangYang duan zheng SHI HuiJi Key Laboratory of Applied Mechanics Tsinghua UniversityChinese Ministry of Education

In order to clarify the differences of very high cycle fatigue(VHCF) behavior of nickel based superalloy IN718 with different loading frequencies,stress-controlled fatigue tests were carried out by using ultrasonic testing method(20 KHz) and rotary bending testing method(52.5 Hz),both at room temperatures,to establish stress versus cycles to failure(S-N) *** disclosed that cycles to failure at a given stress level increased with an increase of the applied frequency,i.e.,the higher frequency produced an upper shift of the S-N *** analysis suggested that crack initiation and propagation behaviors had large differences:cracks in low-frequency tests preferentially initiated from multiple sources on the specimen surface,while in high-frequency tests,cracks mostly originated from a unique source of subsurface ***,frequency-involved modeling was proposed,based on the damage accumulation theory,which could well illustrate qualitatively those comparisons due to different loading frequencies.

关键词： frequency effect very high cycle fatigue IN718 superalloy

Observation and mechanism of non-uniform distribution of tin nuclei in preparing vapor diffusion coated Nb_(3)Sn thin film for SRF applications

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Nuclear Science and Techniques 2025年第1期36卷 22-34页

作者： Shuai Wu Yang Ye Zi-Qin Yang Yuan He Jian-Peng Li Guang-Ze Jiang Lu Li Shi-Chun Huang An-Dong Wu Hang-Xu Li Shao-Hua Lu Tao Liu Feng Qiu Cang-Long Wang Ji-zheng duan Teng Tan Zhi-Jun Wang Sheng-Hu Zhang Hong-Wei Zhao Wen-Long Zhan Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Advanced Energy Science and Technology Guangdong Laboratory Huizhou 516007China School of Microelectronics Dalian University of TechnologyDalian 116000China

Growth of high-quality Nb_(3)Sn thin films for superconducting radiofrequency(SRF)applications using the vapor diffusion method requires a uniform distribution of tin nuclei on the niobium(Nb)*** study examines the mechanism underlying the observed non-uniform distribution of tin nuclei with tin chloride SnCl_(2).Electron backscatter diffraction(EBSD)analysis was used to examine the correlation between the nucleation behavior and orientation of niobium grains in the *** findings of the density functional theory(DFT)simulation are in good agreement with the experimental results,showing that the non-uniform distribution of tin nuclei is the result of the adsorption energy of SnCl_(2)molecules by varied niobium grain *** analysis indicated that the surface roughness and grain size of niobium also played significant roles in the nucleation *** study provides valuable insights into enhancing the surface pretreatment of niobium substrates during the growth of Nb_(3)Sn thin films using the vapor diffusion method.

关键词： Nucleation Tin chloride Non-uniform distribution Vapor diffusion Crystal orientation Adsorption energy

Molecular dynamics study on the nano-void growth and coalescence at grain boundary

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 86-93页

作者： LIN EnQiang NIU LiSha SHI HuiJi duan zheng Applied Mechanics Laboratory School of Aerospace Tsinghua University Beijing 100084 China

Molecular dynamics simulations using embedded atom method (EAM) potential were performed to study nano-void growth and coalescence at grain boundary in face-centered cubic bicrystal copper. Thin-plate specimens subjected to uniaxial tension strain with one-void and two-void at the centered grain boundary were employed to analyze the effect of specimen size, temperature and applied strain rate on the stress-strain response, incipient yield strength and macroscopic effective Young's modulus. The evolutions of dislocations, twin bands and void shapes under different specimen sizes were also presented. The obtained results show that, regardless of the void numbers, the specimen sizes, temperature, the applied strain rate had significant influence on the void shape evolution, stress-strain curve and incipient yield strength, while negligible effects on the macroscopic effective Young's modulus except for the temperature. Moreover, the voids growth rate along the grain boundary was also found to be associated with the specimen sizes.

关键词： bicrystal void growth void coalescence grain boundary molecular dynamics simulations embedded atom method

Monitoring Multi-Temporal Changes of Lakes on the Tibetan Plateau Using Multi-Source Remote Sensing Data from 1992 to 2019:A Case Study of Lake Zhari Namco

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Journal of Earth Science 2024年第5期35卷 1679-1691页

作者： Juan Wu Chang-Qing Ke Yu Cai zheng duan Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural ResourcesSchool of Geography and Ocean ScienceNanjing UniversityNanjing 210023China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing 210023China Guangxi Water and Power Design Institute Co. LtdNanning 530022China Collaborative Innovation Center of South China Sea Studies Nanjing 210023China Department of Physical Geography and Ecosystem Science Lund UniversityLund 22362Sweden

Lake level,area and volume are sensitive indicators of climate *** present,many studies have focused on the interannual water balance of lakes,but lake level and area can change remarkably with seasons,especially for lakes with seasonal ice *** Namco,a seasonal frozen lake,was selected as an example to investigate its seasonal water ***-source altimetry and Landsat data were used to obtain the seasonal lake level and area from 1992 to 2019,and seasonal lake volume variations were also *** results indicated the average lake level,area and volume in autumn were the *** lake level,area,and volume experienced three turning points approximately in 2000,2010,and 2016,and showed an overall increasing trend from 1992 to 2019,with slopes of 0.15 m/year,2.17 km^(2)/year,and 0.14 km^(3)/year,*** lake area expanded significantly in autumn,which was related to the abundant *** time of land surface runoff,increased temperature,and evaporation may be the reason for the low lake level and volume in *** precipitation was the dominant factor of water balance,which explained 62.09%,62.43%,and 62.10%of the variations in lake level,area,and volume,respectively.

关键词： lake level lake area lake volume satellite altimetry landsat Zhari Namco hydrogeology

Numerical simulation of drop weight impact sensitivity evaluation criteria for pressed PBXs

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Defence Technology（防务技术） 2023年第1期19卷 76-90页

作者： Hong-zheng duan Yan-qing Wu Kun Yang Feng-lei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China

A thorough understanding of drop-weight impacted responses for polymer-bonded explosives(PBXs)is significant to evaluate their impact *** characteristics of the drop-weight impacted pressed PBXs including deforming,fracturing,forming a local high-temperature region and igniting,were simulated using a coupled mechanical-thermo-chemical model integrating micro-defects evolution.A novel evaluation method for impact sensitivity is established using the relation between the input kinetic energy and the output energy due to deformation,crushing energy,local hot spot energy and *** effects of impact velocity on sensitivity were analyzed and the critical local ignition impact velocity is determined as 4.0-4.5 m/*** simulated results show that shear-crack friction heating is the dominant ignition *** region along the boundary of PBXs sample is the most hazardous regions where ignition first *** propagation of stress wave in PBXs causes shear-crack hotspot and bulk temperature exhibiting an approximate 45°direction evolution path,which is the main reason that dominated damage-ignition region transits from the boundary to the central of sample.

关键词： Polymer-bonded explosives(PBXs) Drop weight impact Numerical simulation Sensitivity evaluation criterion Hotspot mechanism

Divergent intramolecular reactions between phosphines and alkynes

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Chinese Chemical Letters 2020年第2期31卷 329-332页

作者： Yanying Song Lili Wang zheng duan Francois Mathey College of Chemistry and Molecular Engineering International Phosphorus LaboratoryInternational Joint Research Laboratory for Functional Organophosphorus Materials of Henan ProvinceZhengzhou UniversityZhengzhou 450001China

A divergent intramolecular reaction of phosphine tethered alkyne in protic solvent was *** provided a novel and simple access to a large variety of(Z)-alkenylphosphine oxides and phospholane *** preliminary studies suggested that these divergent reactions are closely related to the reaction condition and molecular structure.A possible mechanism of C-P bond cleavage of a pentacoordinated hydroxyphosphorane intermediate was proposed.

关键词： C-P bond cleavage Phosphine Alkyne Alkenylphosphine Phospholane

The effect of large deformation and material nonlinearity on gel indentation

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Acta Mechanica Sinica 2012年第4期28卷 1058-1067页

作者： zheng duan Yonghao An Jiaping Zhang Hanqing Jiang Transport and Energy Arizona State UniversityTempe AZ 85287 USA

A gel, an aggregate of polymers with solvents, has dual attributes of solid and liquid as solvent migrates in and out of the polymer network. Indentation has recently been used to characterize the mechanical properties of gels. This paper evaluates the effects of large deformation and material nonlinearity on gel indentation through theoretical modeling and finite element analysis. It is found that large deformation significantly affects the interpretation of the experimen- tal observations and the classical relation between indenta- tion force and depth has limitations for large deformation. The material nonlinearity does not play a very important role on indentation experiment so that the poroelasticity is a good approximation. Based on these observations, this paper proposes an alternative approach to measure the mechanical properties of gels, namely, uniaxial compression experiment.

关键词： Gel indentation Large deformation Finite element simulation

Iodine Mediated Efficient Formation of Ferrocenylcyanide in Aqueous Solution

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Chinese Chemical Letters 2006年第7期17卷 880-882页

作者： zheng duan Zhong Xian LI Yang Jie WU Chemistry Department Henan Key Laboratory of Chemical Biology and Organic Chemistry Key Laboratory of Applied Chemistry of Henan Universities Zhengzhou University Zhengzhou 450052

Ferrocenecarboxyaldehyde reacted with iodine in commercial available ammonia water gave ferrocenylcyanide with high yield.

关键词： Ferrocenylcyanide iodine aqueous ammonia preparation.

FeCl_3 catalyzed diarylmethanes formations

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Chinese Chemical Letters 2009年第5期20卷 511-513页

作者： Zhong Xian Li zheng duan Yang Jie Wu Chemistry Department Key Lab of Chemical Biology and Organic Chemistry of Henan Province Key and Open Lab of Applied Chemistry of Henan Universities Zhengzhou University Zhengzhou 450052 PR China

Under mild condition, using FeCl3 as catalyst, a series of fnnctionalized diarylmethanes were prepared efficiently from the reactions of arenes with paraformaldehyde. This catalytic system is not sensitive to air and ... 详细信息

关键词： Diarylmethanes Paraformaldehyde FeCl3