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1. Study on the Influence of the Cavitation of the Feedwater Pump in the Nuclear Power Unit Cogeneration Mode

Author

Ning Gao, Jiaye Shao, Tao Geng, Zhaokai Xing, and Ze Song

Subjects
History, Computer Science Applications, Education
Abstract

This paper conducts modeling and simulation of a nuclear power cogeneration unit system, and analyzes the impact of feedwater pump cavitation through important transient conditions such as steam turbine tripping, load rejection, and feedwater pump tripping. The simulation results show that cogeneration The influence of the mode on the NPSH of the feedwater front pump is generally not large, and the NPSH of the feedwater front pump is slightly improved in all working conditions. Provide a reference for the safe and stable operation of nuclear power cogeneration units.

Published
2022
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4. Trap-assisted photomultiplication in a-IGZO/p-Si heterojunction ultraviolet photodiodes

Author

Wei-Ning Gao, Ya-Hsin Hsiao, Chia-Jung Chen, Wen-Yi Li, and Chun-Ying Huang

Subjects
Materials science, business.industry, Heterojunction, Condensed Matter Physics, medicine.disease_cause, Atomic and Molecular Physics, and Optics, Photodiode, law.invention, Trap (computing), Mechanics of Materials, law, Signal Processing, medicine, Optoelectronics, General Materials Science, Electrical and Electronic Engineering, business, Ultraviolet, Civil and Structural Engineering
Abstract

Many applications require a photodetector (PD) with a large gain to detect very low levels of ultraviolet (UV) light. However, a large gain is generally produced using an impact ionization process, which requires a very large applied voltage. This study demonstrates a photomultiplication (PM)-type UV PD with a simple structure that uses an a-IGZO/p-Si heterojunction. The device exhibits an external quantum efficiency (EQE) of 2565% under 325 nm illumination at a reverse bias of −5 V. The oxygen vacancy (Vo) state in a-IGZO is relaxed to a deep bandgap but is fully occupied by two electrons. Vo with doubly charged Vo 2+ or singly charged Vo + can be excited by UV light. This produces free electrons. There is a high EQE at low reverse-bias because trapped electrons are emitted from the Vo. The IGZO/Si heterojunction also has a high response speed (∼1 ms) in the self-powered mode because the built-in potential separates electron–hole pairs immediately. This study shows that an a-IGZO/p-Si heterojunction not only acts as a PM-type PD with a low driving voltage but also as a high-speed self-powered PD to reduce power consumption.

Published
2020
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5. Research of photon correlation technology

Author

Qian Xiao, Ning Gao, and Lianying Zou

Subjects
Photon correlation, Nuclear physics, Physics
Abstract

Photon correlation technology is an important technology in the field of nanoparticle measurement at present. This paper expounds the research significance of photon correlation technology, introduces the research background and basic concepts of this technology, and studies and analyzes the research status of the correlation algorithm of the new photon correlator. Finally, prospect and application development trend of this technology are analyzed, from the aspects of practicability, application environment and hardware conditions, the difficulties faced by the photon correlation technology are put forward. There are some difficulties when the photon correlator needs to meet the requirements of accuracy, small sampling interval and large dynamic range, this article presents some possible solutions.

Published
2020
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6. Subsurface Facet-fisheye Induced Failure of Titanium Alloy under Very High Cycle Fatigue

Author

Xinxin Xing, Wei Li, Li Meng, and Ning Gao

Subjects
Facet (geometry), Materials science, Titanium alloy, Fatigue testing, Composite material
Abstract

Very high cycle fatigue test under pulsating tension was performed to investigate the subsurface failure mechanism of a titanium alloy. A peculiar region, called “facets cluster zone (FCZ)”, is located at the center of fisheye. The slip-like patterns on facet surface, coalescence of nanoscale cracks and growth of microcracks in the maximum shear stress plane are observable. Combined with the evaluation of stress intensity factors at crack tips, the subsurface failure processes are summarized as: (a) localization of plastic strain, (b) occurrence of slip lines, (c) nucleation of microcracks, (d) coalescence and growth of microcracks, (f) occurrence of the FCZ, (g) formation of fisheye and (i) unstable crack growth until final fracture.

Published
2020
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7. Clustering and dislocation loop punching induced by different noble gas bubbles in tungsten: a molecular dynamics study

Author

Huiqiu Deng, Ning Gao, Yangchun Chen, Wangyu Hu, Fei Gao, and Jingzhong Fang

Subjects
Materials science, chemistry.chemical_element, Noble gas (data page), Tungsten, Condensed Matter Physics, Molecular physics, Computer Science Applications, Loop (topology), Molecular dynamics, Neon, chemistry, Mechanics of Materials, Modeling and Simulation, General Materials Science, Dislocation, Punching, Helium
Published
2019
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8. Nucleation and growth of helium bubble at (110) twist grain boundaries in tungsten studied by molecular dynamics*

Author

Ning Gao, Shangquan Zhao, Ning Li, Guang Ran, and Fang-Biao Li

Subjects
Materials science, Condensed matter physics, Plane (geometry), Bubble, Nucleation, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, Tungsten, 021001 nanoscience & nanotechnology, 01 natural sciences, chemistry, 0103 physical sciences, Atom, Grain boundary, Dislocation, 010306 general physics, 0210 nano-technology, Helium
Abstract

Migration of He atoms and growth of He bubbles in high angle twist grain boundaries (HAGBs) in tungsten (W) are investigated by atomic simulation method. The energy and free volume (FV) of grain boundary (GB) are affected by the density and structure of dislocation patterns in GB. The migration energy of the He atom between the neighboring trapping sites depends on free volume along the migration path at grain boundary. The region of grain boundary around the He bubble forms an ordered crystal structure when He bubble grows at certain grain boundaries. The He atoms aggregate on the grain boundary plane to form a plate-shape configuration. Furthermore, high grain boundary energy (GBE) results in a large volume of He bubble. Thus, the nucleation and growth of He bubbles in twist grain boundaries depend on the energy of grain boundary, the dislocation patterns and the free volume related migration path on the grain boundary plane.

Published
2019
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10. Effects of temperature and point defects on the stability of C15 Laves phase in iron: A molecular dynamics investigation

Author

Guang-Hong Lu, Ning Gao, Hao Wang, and Zhong-Wen Yao

Subjects
Molecular dynamics, Materials science, 0103 physical sciences, General Physics and Astronomy, Thermodynamics, 02 engineering and technology, Laves phase, 021001 nanoscience & nanotechnology, 010306 general physics, 0210 nano-technology, 01 natural sciences, Stability (probability), Crystallographic defect
Published
2018
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11. Structural Distortion and Defects in Ti 3 AlC 2 irradiated by Fe and He Ions

Author

Lilong Pang, Jianrong Sun, Zhiguang Wang, Hailong Chang, Minghuan Cui, Xuesong Fang, Kongfang Wei, Ning Gao, Tielong Shen, Qing Huang, Cunfeng Yao, Xing Gao, Bingsheng Li, and Wen-Hao He

Subjects
010302 applied physics, Diffraction, Materials science, Analytical chemistry, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Fluence, Ion, Transmission electron microscopy, Distortion, 0103 physical sciences, Irradiation, 0210 nano-technology
Abstract

Ti3AlC2 samples are irradiated in advance by 3.5MeV Fe-ion to the fluence of 1.0×10 16 ion/cm 2 , and then are implanted by 500 keV He-ion with the fluence of 1.0×10 17 ion/cm 2 at room temperature. The irradiated samples are investigated by grazing incidence x-ray diffraction (GIXRD) and transmission electron microscopy (TEM). GIXRD results show serious structural distortion, but without amorphization in the irradiated samples. Fe-ion irradiation and He-ion implantation create much more serious structural distortion than single Fe-ion irradiation. TEM results reveal that there are a large number of defect clusters in the damage region, and dense spherical He bubbles appear in the He depositional region. It seems that the pre-damage does not influence the growth of He bubbles, but He-ion implantation influences the pre-created defect configurations.

Published
2018
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12. Anisotropic Migration of Defects under Strain Effect in BCC Iron

Author

Fei Gao, Zhiguang Wang, and Ning Gao

Subjects
010302 applied physics, Materials science, Strain (chemistry), Condensed matter physics, Uniaxial tension, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Atomic simulation, Vacancy defect, 0103 physical sciences, Strain effect, Dumbbell, 0210 nano-technology, Anisotropy
Abstract

The basic properties of defects (self-interstitial and vacancy) in BCC iron under uniaxial tensile strain are investigated with atomic simulation methods. The formation and migration energies of them show different dependences on the directions of uniaxial tensile strain in two different computation boxes. In box-1, the uniaxial tensile strain along the direction influences the formation and migration energies of the dumbbell but slightly affects the migration energy of a single vacancy. In box-2, the uniaxial tensile strain along the direction influences the formation and migration energies of both vacancy and interstitials. Especially, a dumbbell has a lower migration energy when its migration direction is the same or close to the strain direction, while along these directions, a vacancy has a higher migration energy. All these results indicate that the uniaxial tensile strain can result in the anisotropic formation and migration energies of simple defects in materials.

Published
2017
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13. Long-time atomistic dynamics through a new self-adaptive accelerated molecular dynamics method

Author

Ning Gao, Fei Gao, Shengbai Zhang, Richard J. Kurtz, Damien West, and L Yang

Subjects
Ostwald ripening, Chemistry, Coupled motion, Dynamics (mechanics), Self adaptive, Nanotechnology, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Displacement (vector), Molecular dynamics, symbols.namesake, Chemical physics, Vacancy defect, 0103 physical sciences, Cluster (physics), symbols, General Materials Science, 010306 general physics, 0210 nano-technology
Abstract

A self-adaptive accelerated molecular dynamics method is developed to model infrequent atomic-scale events, especially those events that occur on a rugged free-energy surface. Key in the new development is the use of the total displacement of the system at a given temperature to construct a boost-potential, which is slowly increased to accelerate the dynamics. The temperature is slowly increased to accelerate the dynamics. By allowing the system to evolve from one steady-state configuration to another by overcoming the transition state, this self-evolving approach makes it possible to explore the coupled motion of species that migrate on vastly different time scales. The migrations of single vacancy (V) and small He-V clusters, and the growth of nano-sized He-V clusters in Fe for times in the order of seconds are studied by this new method. An interstitial-assisted mechanism is first explored for the migration of a helium-rich He-V cluster, while a new two-component Ostwald ripening mechanism is suggested for He-V cluster growth.

Published
2017
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14. H-ion Irradiation-induced Annealing in He-ion Implanted 4H-SiC

Author

Lilong Pang, Kongfang Wei, Yabin Zhu, Yanbin Sheng, Jin Jin, Jianrong Sun, Xuesong Fang, Peng Luo, Zhiguang Wang, Ning Gao, Si-Xiang Zhao, Zhiwei Ma, Pengfei Tai, Hailong Chang, Dong Wang, Hongpeng Zhang, Wen-Hao He, Tianyu Deng, Jin-Xin Peng, Yu-Xuan Huang, Minghuan Cui, Xing Gao, Tielong Shen, Cunfeng Yao, Bingsheng Li, Yi Han, and Chao Liu

Subjects
Annealing (metallurgy), Phonon, business.industry, Analytical chemistry, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Fluence, Ion, symbols.namesake, Raman line, 0103 physical sciences, symbols, Optoelectronics, Wafer, Irradiation, 010306 general physics, 0210 nano-technology, business, Raman spectroscopy
Abstract

Radiation-induced defect annealing in He+ ion-implanted 4H-SiC via H+ ion irradiation is investigated by Raman spectroscopy. There are 4H-SiC wafers irradiated with 230 keV He+ ions with fluences ranging from 5.0x10(15) cm(-2) to 2.0 x 10(16) cm(-2) at room temperature. The post-implantation samples are irradiated by 260 keV H+ ions at a fluence of 5.0 x 10(15) cm(-2) at room temperature. The intensities of Raman lines decrease after He implantation, while they increase after H irradiation. The experimental results present that the magnitude of Raman line increment is related to the concentration of pre-existing defects formed by He implantation. A strong new peak located near 966 cm(-1), which is assigned to 3C-SiC LO (Gamma) phonon, is found in the He-implanted sample with a fluence of 5.0 x 10(15) cm(-2) followed by H irradiation. However, for the He-implanted sample with a fluence of 2.0 x 10(16) cm(-2) followed by H irradiation, no 3C-SiC phonon vibrations are found. The detailed reason for H irradiation-induced phase transformation in the He-implanted 4H-SiC is discussed.

Published
2017
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15. Effect of Strain Field on Threshold Displacement Energy of Tungsten Studied by Molecular Dynamics Simulation

Author

Xing Gao, Dong Wang, Richard J. Kurtz, Wen-Hao He, Lilong Pang, Ning Gao, Zhiguang Wang, and Wahyu Setyawan

Subjects
Physics, Strain (chemistry), Field (physics), Tension (physics), General Physics and Astronomy, chemistry.chemical_element, Nanotechnology, 02 engineering and technology, Tungsten, 021001 nanoscience & nanotechnology, Compression (physics), 01 natural sciences, Molecular physics, 010305 fluids & plasmas, Molecular dynamics, chemistry, Vacancy defect, 0103 physical sciences, Threshold displacement energy, 0210 nano-technology
Abstract

The influence of strain field on defect formation energy and threshold displacement energy (Ed) in body-centered cubic tungsten (W) is studied with molecular dynamics simulation. Two different W potentials (Fikar and Juslin) are compared and the results indicate that the connection distance and selected function linking the short-range and long-range portions of the potentials affect the threshold displacement energy and its direction-specific values. The minimum Ed direction calculated with the Fikar potential is 〈100〉 and with the Juslin potential is 〈111〉. Nevertheless, the most stable self-interstitial configuration is found to be a 〈111〉-crowdion for both the potentials. This stable configuration does not change with the applied strain. Varying the strain from compression to tension increases the vacancy formation energy while decreases the self-interstitial formation energy. The formation energy of a self-interstitial changes more significantly than a vacancy such that Ed decreases with the applied hydrostatic strain from compression to tension.

Published
2016
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16. First-principles investigation of vacancies in LiTaO3

Author

Xing Gao, Dong Wang, Ning Gao, Zhiguang Wang, Lilong Pang, and Wen-Hao He

Subjects
010302 applied physics, Chemistry, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Oxygen, Electronic states, Crystal, chemistry.chemical_compound, Vacancy defect, 0103 physical sciences, Lithium tantalate, General Materials Science, Oxygen rich, Atomic physics, 0210 nano-technology
Abstract

Formation energies of neutral and charged vacancies in lithium tantalate, as well as their electronic states have been investigated through first-principles calculations. It is found out that [Formula: see text], [Formula: see text] and [Formula: see text] are the most energy favorable vacancies on O, Li and Ta sites respectively. The formation energy of vacancy on the O site is lower in oxygen poor environments than that in oxygen rich environments, and the formation energy of vacancy on the cation site is lower in oxygen rich environments than that in oxygen poor environments. Among all types of neutral vacancies considered in this study, the energy of Li partial Schottky reaction, 2[Formula: see text] + [Formula: see text], is the lowest at almost all considered chemical environments. Taking into account the distribution of vacancy induced energy levels, we suggest that either [Formula: see text] or [Formula: see text] is responsible for the light absorption band around 460 nm observed in annealed LiTaO3 crystal.

Published
2016
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17. Cu Segregation at Σ 5 Symmetrical Grain Boundary in α -Fe: Atomic-Level Simulations

Author

Dong Wang, Zhiguang Wang, Fei Gao, and Ning Gao

Subjects
Work (thermodynamics), Materials science, Chemical physics, Precipitation (chemistry), Monte Carlo method, Molecular statics, Cluster size, General Physics and Astronomy, Grain boundary, Embrittlement
Abstract

Cu-rich precipitation is regarded as one of the main issues causing embrittlement of ferritic steels. In the present work, the Cu segregation at Σ5 {012} symmetrical grain boundary (GB) in BCC iron is investigated by combining Metropolis Monte Carlo and molecular statics approaches. The segregation driven energies of Cu clusters decrease with increasing the distance from GB and also depend on the cluster size. The length scales associated with Cu segregation at GB are determined. All these results indicate that Cu atoms prefer to segregate at S5 GB, which may account for the embrittlement of ferritic steels. The present results provide important knowledge to understand the detailed mechanisms of Cu segregation at GB and also the possible effects on mechanical properties of α-Fe.

Published
2014
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18. Helium-Implantation-Induced Damage in NHS Steel Investigated by Slow-Positron Annihilation Spectroscopy

Author

Xingzhong Cao, Minghuan Cui, Bi-Tao Hu, Jianrong Sun, Zhiguang Wang, Xing Gao, Peng Zhang, Bingsheng Li, Kongfang Wei, Lilong Pang, Ning Gao, Peng Song, Cunfeng Yao, Hongpeng Zhang, Huiping Zhu, Tielong Shen, Y.F. Li, Yabin Zhu, Ji Wang, Hailong Chang, Dong Wang, and Yanbin Sheng

Subjects
Materials science, chemistry, Silicon, Diffusion, Vacancy defect, General Physics and Astronomy, chemistry.chemical_element, Fluence, Molecular physics, Deposition (law), Helium, Ion, Positron annihilation spectroscopy
Abstract

Evolutions of defects and helium contained defects produced by atomic displacement and helium deposition with helium implantation at different temperatures in novel high silicon (NHS) steel are investigated by a slow positron beam. Differences of the defect information among samples implanted by helium to a fluence of 1 x 10(17) ions/cm(2) at room temperature, 300 degrees C, 450 degrees C and 750 degrees C are discussed. It is found that the mobility of vacancies and vacancy clusters, a recombination of vacancy-type defects and the formation of the He-V complex lead to the occurrence of these differences. At high temperature irradiations, a change of the diffusion mechanism of He atoms/He bubbles might be one of the reasons for the change of the S-parameter.

Published
2014
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19. The Energy State and Phase Transition of Cu Clusters in bcc-Fe Studied by a Molecular Dynamics Simulation

Author

Kongfang Wei, Shixu Zhang, Zhiguang Wang, and Ning Gao

Subjects
Stress (mechanics), Phase transition, Crystallography, Molecular dynamics, Condensed matter physics, Common neighbor, Binding energy, General Physics and Astronomy, Total energy
Abstract

The total energy of bcc Fe containing Cu clusters with different sizes and number densities are calculated using the molecular dynamics (MD) method. The results indicate that the Cu atoms prefer to form Cu clusters instead of being uniformly distributed in the bcc Fe matrix. The binding energy of substitutional Cu to Cu clusters is also found to increase with the number of Cu atoms. For a large-sized Cu precipitate, the change of the local stress state is found to relate to the phase transition from bcc to fcc Cu based on MD and common neighbor analysis.

Published
2012
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22. Calibration of RPC-based muon detector at BESIII

Author

Yu-Guang, Xie, primary, Wei-Dong, Li, additional, Yu-Tie, Liang, additional, Zheng-Yun, You, additional, Ya-Jun, Mao, additional, Jia-Wen, Zhang, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Cheng-Dong, Fu, additional, Yuan-Ning, Gao, additional, Kang-Lin, He, additional, Miao, He, additional, Chun-Fei, Hua, additional, Bin, Huang, additional, Xing-Tao, Huang, additional, Xiao-Bin, Ji, additional, Fei, Li, additional, Hai-Bo, Li, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Qiu-Guang, Liu, additional, Suo, Liu, additional, Ying-Jie, Liu, additional, Qiu-Mei, Ma, additional, Xiang, Ma, additional, Ze-Pu, Mao, additional, Xiao-Hu, Mo, additional, Ming-Hua, Pan, additional, Cai-Ying, Pang, additional, Rong-Gang, Ping, additional, Ya-Hong, Qin, additional, Jin-Fa, Qiu, additional, Sheng-Sen, Sun, additional, Yong-Zhao, Sun, additional, Ji-Ke, Wang, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Min, Xu, additional, Liang, Yan, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Bing-Yun, Zhang, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yang-Heng, Zheng, additional, Ke-Jun, Zhu, additional, Yong-Sheng, Zhu, additional, Zhi-Li, Zhu, additional, and Jia-Heng, Zou, additional

Published
2010
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23. Helium-vacancy cluster in a single bcc iron crystal lattice

Author

H. Van Swygenhoven, J Chen, M Victoria, and Ning Gao

Subjects
Chemistry, Iron, Binding energy, Molecular Conformation, chemistry.chemical_element, Crystal structure, Cubic crystal system, Condensed Matter Physics, Helium, Molecular physics, Crystallography, Models, Chemical, Ab initio quantum chemistry methods, Vacancy defect, Atom, Cluster (physics), Computer Simulation, General Materials Science, Crystallization
Abstract

The properties of the cluster He(n)V, an iron vacancy with an increasing number of He atoms, is studied with molecular statics and molecular dynamics simulations. A study of the binding energy of the self-interstitial atom (SIA) and the He, shows that from n = 6 the He(n)V cluster is stable and cannot shrink anymore, and from n = 16 the He(n)V(2) cluster is stabilized by the emission of SIA in the form of a (110) dumbbell. Calculation of the pressure exercised by the He(n)V cluster shows local peak normal stress and shear stress values up to 9 GPa and 4 GPa, respectively. The local configurations of He(n)V suggest that with increasing helium content, a high symmetry configuration close to a face centered cubic lattice is formed.

Published
2011
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24. BESIII track fitting algorithm

Author

Ji-Ke, Wang, primary, Ze-Pu, Mao, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Cheng-Dong, Fu, additional, Yuan-Ning, Gao, additional, Kang-Lin, He, additional, Miao, He, additional, Chun-Fei, Hua, additional, Bin, Huang, additional, Xing-Tao, Huang, additional, Xiao-Bin, Ji, additional, Fei, Li, additional, Bai-Bo, Li, additional, Wei-Dong, Li, additional, Yu-Tie, Liang, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Suo, Liu, additional, Ying-Jie, Liu, additional, Qiu-Mei, Ma, additional, Xiang, Ma, additional, Ya-Jun, Mao, additional, Xiao-Hu, Mo, additional, Ming-Hua, Pan, additional, Cai-Ying, Pang, additional, Rong-Gang, Ping, additional, Ya-Hong, Qin, additional, Jin-Fa, Qiu, additional, Sheng-Sen, Sun, additional, Yong-Zhao, Sun, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Yu-Guang, Xie, additional, Min, Xu, additional, Liang, Yan, additional, Zheng-Yun, You, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Bing-Yun, Zhang, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yang-Heng, Zheng, additional, Ke-Jun, Zhu, additional, Yong-Sheng, Zhu, additional, Zhi-Li, Zhu, additional, and Jia-Heng, Zou, additional

Published
2009
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25. Track reconstruction in the BESIII muon counter

Author

Yu-Tie, Liang, primary, Kun, Liu, additional, Zheng-Yun, You, additional, Ya-Jun, Mao, additional, Wei-Dong, Li, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Cheng-Dong, Fu, additional, Yuan-Ning, Gao, additional, Lei, Han, additional, Shao-Qing, Han, additional, Kang-Lin, He, additional, Miao, He, additional, Ji-Feng, Hu, additional, Xiao-Wei, Hu, additional, Bin, Huang, additional, Xing-Tao, Huang, additional, Lu-Kui, Jia, additional, Xiao-Bin, Ji, additional, Hai-Bo, Li, additional, Bei-Jiang, Liu, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Ying, Liu, additional, Yong, Liu, additional, Tao, Luo, additional, Qi-Wen, Lu, additional, Qiu-Mei, Ma, additional, Xiang, Ma, additional, Ze-Pu, Mao, additional, Xiao-Hu, Mo, additional, Fei-Peng, Ning, additional, Rong-Gang, Ping, additional, Jin-Fa, Qiu, additional, Wen-Bo, Song, additional, Sheng-Sen, Sun, additional, Xiao-Dong, Sun, additional, Yong-Zhao, Sun, additional, Hao-Lai, Tian, additional, Ji-Ke, Wang, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Zhi, Wu, additional, Yu-Guang, Xie, additional, Min, Xu, additional, Jie, Yan, additional, Liang, Yan, additional, Jian, Yao, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Lei, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yang-Heng, Zheng, additional, Yong-Sheng, Zhu, additional, and Jia-Heng, Zou, additional

Published
2009
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26. Study of BESIII MUC offline software with cosmic-ray data

Author

Yu-Tie, Liang, primary, Ya-Jun, Mao, additional, Zheng-Yun, You, additional, Wei-Dong, Li, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Cheng-Dong, Fu, additional, Yuan-Ning, Gao, additional, Lei, Han, additional, Shao-Qing, Han, additional, Kang-Lin, He, additional, Miao, He, additional, Ji-Feng, Hu, additional, Xiao-Wei, Hu, additional, Bin, Huang, additional, Xing-Tao, Huang, additional, Lu-Kui, Jia, additional, Xiao-Bin, Ji, additional, Hai-Bo, Li, additional, Bei-Jiang, Liu, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Ying, Liu, additional, Yong, Liu, additional, Tao, Luo, additional, Qi-Wen, Lu, additional, Qiu-Mei, Ma, additional, Xiang, Ma, additional, Ze-Pu, Mao, additional, Xiao-Hu, Mo, additional, Fei-Peng, Ning, additional, Rong-Gang, Ping, additional, Jin-Fa, Qiu, additional, Wen-Bo, Song, additional, Sheng-Sen, Sun, additional, Xiao-Dong, Sun, additional, Yong-Zhao, Sun, additional, Hao-Lai, Tian, additional, Ji-Ke, Wang, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Zhi, Wu, additional, Yu-Guang, Xie, additional, Min, Xu, additional, Jie, Yan, additional, Liang, Yan, additional, Jian, Yao, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Lei, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yang-Heng, Zheng, additional, Yong-Sheng, Zhu, additional, and Jia-Heng, Zou, additional

Published
2009
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27. Decay vertex reconstruction and 3-dimensional lifetime determination at BESIII

Author

Min, Xu, primary, Kang-Lin, He, additional, Zi-Ping, Zhang, additional, Yi-Fang, Wang, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Cheng-Dong, Fu, additional, Yuan-Ning, Gao, additional, Lei, Han, additional, Shao-Qing, Han, additional, Miao, He, additional, Ji-Feng, Hu, additional, Xiao-Wei, Hu, additional, Bin, Huang, additional, Xing-Tao, Huang, additional, Lu-Kui, Jia, additional, Xiao-Bin, Ji, additional, Hai-Bo, Li, additional, Wei-Dong, Li, additional, Yu-Tie, Liang, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Ying, Liu, additional, Yong, Liu, additional, Tao, Luo, additional, Qi-Wen, Lü, additional, Qiu-Mei, Ma, additional, Xiang, Ma, additional, Ya-Jun, Mao, additional, Ze-Pu, Mao, additional, Xiao-Hu, Mo, additional, Fei-Peng, Ning, additional, Rong-Gang, Ping, additional, Jin-Fa, Qiu, additional, Wen-Bo, Song, additional, Sheng-Sen, Sun, additional, Xiao-Dong, Sun, additional, Yong-Zhao, Sun, additional, Hao-Lai, Tian, additional, Ji-Ke, Wang, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Zhi, Wu, additional, Yu-Guang, Xie, additional, Jie, Yan, additional, Liang, Yan, additional, Jian, Yao, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Lei, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yang-Heng, Zheng, additional, Yong-Sheng, Zhu, additional, and Jia-Heng, Zou, additional

Published
2009
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29. Software alignment of the BESIII main drift chamber using the Kalman Filter method

Author

Ji-Ke, Wang, primary, Ze-Pu, Mao, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Cheng-Dong, Fu, additional, Yuan-Ning, Gao, additional, Kang-Lin, He, additional, Miao, He, additional, Chun-Fei, Hua, additional, Bin, Huang, additional, Xing-Tao, Huang, additional, Xiao-Bin, Ji, additional, Fei, Li, additional, Hai-Bo, Li, additional, Wei-Dong, Li, additional, Yu-Tie, Liang, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Suo, Liu, additional, Ying-Jie, Liu, additional, Qiu-Mei, Ma, additional, Xiang, Ma, additional, Ya-Jun, Mao, additional, Xiao-Hu, Mo, additional, Ming-Hua, Pan, additional, Cai-Ying, Pang, additional, Rong-Gang, Ping, additional, Ya-Hong, Qin, additional, Jin-Fa, Qiu, additional, Sheng-Sen, Sun, additional, Yong-Zhao, Sun, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Yu-Guang, Xie, additional, Min, Xu, additional, Liang, Yan, additional, Zheng-Yun, You, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Bing-Yun, Zhang, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yang-Heng, Zheng, additional, Ke-Jun, Zhu, additional, Yong-Sheng, Zhu, additional, Zhi-Li, Zhu, additional, and Jia-Heng, Zou, additional

Published
2009
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30. An experimental study on ferromagnetic nickel nanowires functionalized with antibodies for cell separation

Author

Eui-Hyeok Yang, Ning Gao, and Hongjun Wang

Subjects
Materials science, Cell Survival, Nanowire, Analytical chemistry, chemistry.chemical_element, Bioengineering, Cell Separation, Conjugated system, Cell morphology, Antibodies, Mice, Nickel, Monolayer, Animals, Nanotechnology, General Materials Science, Electrical and Electronic Engineering, Cytotoxicity, Cells, Cultured, Nanowires, Mechanical Engineering, General Chemistry, Platelet Endothelial Cell Adhesion Molecule-1, chemistry, Chemical engineering, Mechanics of Materials, Covalent bond, Yield (chemistry), Microscopy, Electron, Scanning
Abstract

In this paper, a cell separation technique has been explored using antibody-functionalized Ni nanowires. An antibody (anti-CD31) against mouse endothelial cells (MS1) was conjugated to the Ni nanowire surface through self-assembled monolayers (SAMs) and chemical covalent reactions. The measured cytotoxicity was negligible on the CD-31 antibody-functionalized nanowires by the tetrazolium salt (MTT) assay. The use of functionalized nanowires for magnetically separating MS1 cells revealed that the cell separation yield was closely related to cell concentration and the nanowire/cell ratio. Cell separation yield using functionalized Ni nanowires was compared with that using commercial magnetic beads. Considering the volume difference of the material used between the beads and nanowires, antibody-functionalized nanowires showed an obvious advantage in cell separation. Further study on the effect of Ni nanowires on MS1 cells for extended culture confirmed that cell morphology remained comparable to control cells with a lower proliferation rate. This work demonstrates that antibody-functionalized Ni nanowires provide an effective means to separate target cells.

Published
2010
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31. A simulation study on the measurement of D 0 -D̄ 0 mixing parameter y at BESIII

Author

Bin, Huang, primary, Yang-Heng, Zheng, additional, Wei-Dong, Li, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Cheng-Dong, Fu, additional, Yuan-Ning, Gao, additional, Kang-Lin, He, additional, Miao, He, additional, Chun-Fei, Hua, additional, Xing-Tao, Huang, additional, Xiao-Bin, Ji, additional, Hai-Bo, Li, additional, Yu-Tie, Liang, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Qiu-Guang, Liu, additional, Suo, Liu, additional, Ying-Jie, Liu, additional, Qiu-Mei, Ma, additional, Xiang, Ma, additional, Ya-Jun, Mao, additional, Ze-Pu, Mao, additional, Xiao-Hu, Mo, additional, Ming-Hua, Pan, additional, Cai-Ying, Pang, additional, Rong-Gang, Ping, additional, Gang, Qin, additional, Ya-Hong, Qin, additional, Jin-Fa, Qiu, additional, Sheng-Sen, Sun, additional, Yong-Zhao, Sun, additional, Ji-Ke, Wang, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Yu-Guang, Xie, additional, Min, Xu, additional, Liang, Yan, additional, Zheng-Yun, You, additional, Guo-Wei, Yu, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yong-Sheng, Zhu, additional, Zhi-Li, Zhu, additional, and Jia-Heng, Zou, additional

Published
2008
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32. Determination of event start time at BESIII

Author

Xiang, Ma, primary, Ze-Pu, Mao, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Cheng-Dong, Fu, additional, Yuan-Ning, Gao, additional, Kang-Lin, He, additional, Miao, He, additional, Chun-Fei, Hua, additional, Bin, Huang, additional, Xing-Tao, Huang, additional, Xiao-Bin, Ji, additional, Hai-Bo, Li, additional, Wei-Dong, Li, additional, Yu-Tie, Liang, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Qiu-Guang, Liu, additional, Suo, Liu, additional, Ying-Jie, Liu, additional, Qiu-Mei, Ma, additional, Ya-Jun, Mao, additional, Xiao-Hu, Mo, additional, Ming-Hua, Pan, additional, Cai-Ying, Pang, additional, Rong-Gang, Ping, additional, Gang, Qin, additional, Ya-Hong, Qin, additional, Jin-Fa, Qiu, additional, Sheng-Sen, Sun, additional, Yong-Zhao, Sun, additional, Ji-Ke, Wang, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Yu-Guang, Xie, additional, Min, Xu, additional, Liang, Yan, additional, Zheng-Yun, You, additional, Guo-Wei, Yu, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Shi-Lei, Zang, additional, Bing-Yun, Zhang, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yang-Heng, Zheng, additional, Ke-Jun, Zhu, additional, Yong-Sheng, Zhu, additional, Zhi-Li, Zhu, additional, and Jia-Heng, Zou, additional

Published
2008
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33. Track reconstruction using the TSF method for the BESIII main drift chamber

Author

Qiu-Guang, Liu, primary, Shi-Lei, Zang, additional, Wei-Guo, Li, additional, Ze-Pu, Mao, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Cheng-Dong, Fu, additional, Yuan-Ning, Gao, additional, Kang-Lin, He, additional, Miao, He, additional, Chun-Fei, Hua, additional, Bin, Huang, additional, Xing-Tao, Huang, additional, Xiao-Bin, Ji, additional, Fei, Li, additional, Hai-Bo, Li, additional, Wei-Dong, Li, additional, Yu-Tie, Liang, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Suo, Liu, additional, Ying-Jie, Liu, additional, Qiu-Mei, Ma, additional, Xiang, Ma, additional, Ya-Jun, Mao, additional, Xiao-Hu, Mo, additional, Ming-Hua, Pan, additional, Cai-Ying, Pang, additional, Rong-Gang, Ping, additional, Gang, Qin, additional, Ya-Hong, Qin, additional, Jin-Fa, Qiu, additional, Sheng-Sen, Sun, additional, Yong-Zhao, Sun, additional, Ji-Ke, Wang, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Yu-Guang, Xie, additional, Min, Xu, additional, Liang, Yan, additional, Zheng-Yun, You, additional, Guo-Wei, Yu, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Bing-Yun, Zhang, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yang-Heng, Zheng, additional, Ke-Jun, Zhu, additional, Yong-Sheng, Zhu, additional, Zhi-Li, Zhu, additional, and Jia-Heng, Zou, additional

Published
2008
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34. Study of the online event filtering algorithm for BESIII

Author

Cheng-Dong, Fu, primary, Jia-Heng, Zou, additional, Xiao-Hu, Mo, additional, Kang-Lin, He, additional, Jian-Ming, Bian, additional, Guo-Fu, Cao, additional, Xue-Xiang, Cao, additional, Shen-Jian, Chen, additional, Zi-Yan, Deng, additional, Yuan-Ning, Gao, additional, Miao, He, additional, Chun-Fei, Hua, additional, Bin, Huang, additional, Xing-Tao, Huang, additional, Xiao-Bin, Ji, additional, Fei, Li, additional, Hai-Bo, Li, additional, Wei-Dong, Li, additional, Yu-Tie, Liang, additional, Chun-Xiu, Liu, additional, Huai-Min, Liu, additional, Qiu-Guang, Liu, additional, Suo, Liu, additional, Ying-Jie, Liu, additional, Qiu-Mei, Ma, additional, Xiang, Ma, additional, Ya-Jun, Mao, additional, Ze-Pu, Mao, additional, Ming-Hua, Pan, additional, Cai-Ying, Pang, additional, Rong-Gang, Ping, additional, Gang, Qin, additional, Ya-Hong, Qin, additional, Jin-Fa, Qiu, additional, Sheng-Sen, Sun, additional, Yong-Zhao, Sun, additional, Ji-Ke, Wang, additional, Liang-Liang, Wang, additional, Shuo-Pin, Wen, additional, Ling-Hui, Wu, additional, Yu-Guang, Xie, additional, Min, Xu, additional, Liang, Yan, additional, Zheng-Yun, You, additional, Guo-Wei, Yu, additional, Chang-Zheng, Yuan, additional, Ye, Yuan, additional, Bing-Yun, Zhang, additional, Chang-Chun, Zhang, additional, Jian-Yong, Zhang, additional, Xue-Yao, Zhang, additional, Yao, Zhang, additional, Yang-Heng, Zheng, additional, Ke-Jun, Zhu, additional, Yong-Sheng, Zhu, additional, and Zhi-Li, Zhu, additional

Published
2008
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37. Relative stability of amorphous phase versus solid solution in the Ni–Ti system revealed by molecular dynamics simulations

Author

W. S. Lai and Ning Gao

Subjects
Molecular dynamics, Crystallography, Amorphous metal, Structural change, Chemistry, Coordination number, Thermodynamics, General Materials Science, Crystal structure, Condensed Matter Physics, Relative stability, Amorphous solid, Solid solution
Abstract

We employ molecular dynamics simulations with n-body potentials to calculate the energies of solid solutions and metallic glasses in the Ni?Ti system to reveal relative stability of two phases against the change of solute concentration. For Ni1?xTix alloys, the calculations show that the energies of the solid solutions are lower than the amorphous phases when x?0.24 and vice versa for x>0.24, in accord with thermodynamics analysis and experiments. To reveal the underlying physics responsible for this, the evolution of structures in the solid solutions and the amorphous phases are studied via the coordination number (CN) and common neighbour analyses. The results show that, with an increase in Ti concentration, the total average coordination number is close to 12 for all solid solutions owing to the face-centred cubic (fcc) crystalline structure remaining, while it changes from less than 12 to greater than 12 for the amorphous phases, suggesting that more bonds or more fractions of large CNs (>12) exist in the amorphous phases with a high Ti content. The relative stability of the amorphous phases versus the solid solutions revealed by the order of energy is thus correlated with the structural change of the amorphous phases.

Published
2007
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38. Helium-Implantation-Induced Damage in NHS Steel Investigated by Slow-Positron Annihilation Spectroscopy.

Author

Yuan-Fei, Li, Tie-Long, Shen, Xing, Gao, Ning, Gao, Cun-Feng, Yao, Jian-Rong, Sun, Kong-Fang, Wei, Bing-Sheng, Li, Peng, Zhang, Xing-Zhong, Cao, Ya-Bin, Zhu, Li-Long, Pang, Ming-Huan, Cui, Hai-Long, Chang, Ji, Wang, Hui-Ping, Zhu, Dong, Wang, Peng, Song, Yan-Bin, Sheng, and Hong-Peng, Zhang

Subjects
HELIUM, POSITRON beams, THERMAL conductivity, STEEL research, PHYSICS research
Abstract

Evolutions of defects and helium contained defects produced by atomic displacement and helium deposition with helium implantation at different temperatures in novel high silicon (NHS) steel are investigated by a slow positron beam. Differences of the defect information among samples implanted by helium to a fluence of 1 × 1017 ions/cm2 at room temperature, 300°C, 450°C and 750°C are discussed. It is found that the mobility of vacancies and vacancy clusters, a recombination of vacancy-type defects and the formation of the He-V complex lead to the occurrence of these differences. At high temperature irradiations, a change of the diffusion mechanism of He atoms/He bubbles might be one of the reasons for the change of the S-parameter. [ABSTRACT FROM AUTHOR]

Published
2014
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40. The Energy State and Phase Transition of Cu Clusters in bcc-Fe Studied by a Molecular Dynamics Simulation.

Author

Ning Gao, Kong-Fang Wei, Shi-Xu Zhang, and Zhi-Guang Wang

Subjects
*ENERGY levels (Quantum mechanics), *PHASE transitions, *COPPER clusters, *MOLECULAR dynamics, *ALLOTROPY, *BINDING energy
Abstract

The total energy of bcc Fe containing Cu clusters with different sizes and number densities are calculated using the molecular dynamics (MD) method. The results indicate that the Cu atoms prefer to form Cu clusters instead of being uniformly distributed in the bcc Fe matrix. The binding energy of substitutional Cu to Cu clusters is also found to increase with the number of Cu atoms. For a large-sized Cu precipitate, the change of the local stress state is found to relate to the phase transition from bcc to fcc Cu based on MD and common neighbor analysis. [ABSTRACT FROM AUTHOR]

Published
2012
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43. Nucleation and growth of helium bubble at (110) twist grain boundaries in tungsten studied by molecular dynamics.

Author

Fang-Biao Li, Guang Ran, Ning Gao, Shang-Quan Zhao, and Ning Li

Subjects
CRYSTAL grain boundaries, DISCONTINUOUS precipitation, MOLECULAR dynamics, DISLOCATION structure, BUBBLES
Abstract

Migration of He atoms and growth of He bubbles in high angle twist grain boundaries (HAGBs) in tungsten (W) are investigated by atomic simulation method. The energy and free volume (FV) of grain boundary (GB) are affected by the density and structure of dislocation patterns in GB. The migration energy of the He atom between the neighboring trapping sites depends on free volume along the migration path at grain boundary. The region of grain boundary around the He bubble forms an ordered crystal structure when He bubble grows at certain grain boundaries. The He atoms aggregate on the grain boundary plane to form a plate-shape configuration. Furthermore, high grain boundary energy (GBE) results in a large volume of He bubble. Thus, the nucleation and growth of He bubbles in twist grain boundaries depend on the energy of grain boundary, the dislocation patterns and the free volume related migration path on the grain boundary plane. [ABSTRACT FROM AUTHOR]

Published
2019
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44. Effects of temperature and point defects on the stability of C15 Laves phase in iron: A molecular dynamics investigation.

Author

Hao Wang, Ning Gao, Guang-Hong Lü, and Zhong-Wen Yao

Subjects
*MOLECULAR dynamics, *POINT defects, *DISLOCATION loops, *PHASE transitions
Abstract

Molecular dynamics simulations are used to investigate the stabilities of C15 Laves phase structures subjected to temperature and point defects. The simulations based on different empirical potentials show that the bulk perfect C15 Laves phase appears to be stable under a critical temperature in a range from 350 K to 450 K, beyond which it becomes disordered and experiences an abrupt decrement of elastic modulus. In the presence of both vacancy and self-interstitial, the bulk C15 Laves phase becomes unstable at room temperature and prefers to transform into an imperfect body centered cubic (BCC) structure containing free vacancies or vacancy clusters. When a C15 cluster is embedded in BCC iron, the annihilation of interstitials occurs due to the presence of the vacancy, while it exhibits a phase transformation into a (1/2)⟨111⟩ dislocation loop due to the presence of the self-interstitial. [ABSTRACT FROM AUTHOR]

Published
2018
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45. Effects of Grain Boundary Characteristics on Its Capability to Trap Point Defects in Tungsten.

Author

Wen-Hao He, Xing Gao, Ning Gao, Ji Wang, Dong Wang, Ming-Huan Cui, Li-Long Pang, and Zhi-Guang Wang

Subjects
TUNGSTEN, KIRKENDALL effect, ATOMIC spectra, ATOMIC structure, NUCLEAR energy
Abstract

As recombination centers of vacancies (Vs) and self-interstitial atoms (SIAs), firstly grain boundaries (GBs) should have strong capability of trapping point defects. In this study, abilities to trap Vs and SIAs of eight symmetric tilt GBs in tungsten are investigated through first-principles calculations. On the one hand, vacancy formation energyrapidly increases then slowly decreases as the hard-sphere radius r0of the vacancy increases. The value ofis the largest when r0is about 1.38 Å, which is half the distance between the nearest atoms in equilibrium single crystal tungsten. That is, any denser or looser atomic configuration around GBs than that in bulk is helpful to form a vacancy. On the other hand, SIA formation energyat GBs decreases monotonically with increasing the hard-sphere radius of the interstitial sites, which indicates that GBs with larger interstitial sites have stronger ability to trap SIAs. Based on the data obtained for GBs investigated in this study, it is found that the ability to trap Vs increases as the GB energy increases, and the capability of trapping SIAs linearly increases as the excess volume of GB increases. Due to its lowest GB energy and smallest excess volume among all GBs studied, twin GB ∑3(110)[111] has the weakest capability to trap both Vs and SIAs. [ABSTRACT FROM AUTHOR]

Published
2018
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46. Structural Distortion and Defects in Ti3AlC2 irradiated by Fe and He Ions.

Author

Li-Long Pang, Bing-Sheng Li, Tie-Long Shen, Xing Gao, Xue-Song Fang, Ning Gao, Cun-Feng Yao, Kong-Fang Wei, Ming-Huan Cui, Jian-Rong Sun, Hai-Long Chang, Wen-Hao He, Qing Huang, and Zhi-Guang Wang

Subjects
X-ray diffraction, TRANSMISSION electron microscopy, TITANIUM aluminides, AMORPHIZATION, IRRADIATION, HELIUM ions
Abstract

Ti3AlC2 samples are irradiated in advance by 3.5MeV Fe-ion to the fluence of 1.0×1016ion/cm2, and then are implanted by 500 keV He-ion with the fluence of 1.0×1017ion/cm2at room temperature. The irradiated samples are investigated by grazing incidence x-ray diffraction (GIXRD) and transmission electron microscopy (TEM). GIXRD results show serious structural distortion, but without amorphization in the irradiated samples. Fe-ion irradiation and He-ion implantation create much more serious structural distortion than single Fe-ion irradiation. TEM results reveal that there are a large number of defect clusters in the damage region, and dense spherical He bubbles appear in the He depositional region. It seems that the pre-damage does not influence the growth of He bubbles, but He-ion implantation influences the pre-created defect configurations. [ABSTRACT FROM AUTHOR]

Published
2018
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47. Ultra-broadband and polarization-independent planar absorber based on multilayered graphene.

Author

Jiao Wang, Chao-Ning Gao, Yan-Nan Jiang, and Charles Nwakanma Akwuruoha

Subjects
*OPTICAL properties of graphene, *ULTRA-wideband devices, *CRYSTAL structure, *OPTICAL polarization, *ELECTROMAGNETIC spectrum
Abstract

We propose an ultra-broadband and polarization independent planar absorber comprising multilayered graphene. The bandwidth of the proposed absorber is extended by increasing the number of layers of graphene, and it is polarization independent due to its symmetrical unit structure. The full wave simulation results show that an absorber with three graphene-based layers can efficiently harvest an electromagnetic wave with random polarization from 17.9 GHz to 188.7 GHz (i.e., covering frequency regimes from K to D bands and relative bandwidth of ∼ 165%). The physical absorption mechanism of ultra-broadband absorption has been elaborated upon using the destructive interference method and multiple resonances approach in a multilayered medium. The proposed absorber can be used in many applications such as medical treatment, electromagnetic compatibility, and stealth technique. [ABSTRACT FROM AUTHOR]

Published
2017
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48. Anisotropic Migration of Defects under Strain Effect in BCC Iron.

Author

Ning Gao, Fei Gao, and Zhi-Guang Wang

Subjects
*MOLECULAR structure of iron compounds, *ATOMIC mass, *DIFFUSION coefficients, *ANISOTROPY, *DENSITY functional theory
Abstract

The basic properties of defects (self-interstitial and vacancy) in BCC iron under uniaxial tensile strain are investigated with atomic simulation methods. The formation and migration energies of them show different dependences on the directions of uniaxial tensile strain in two different computation boxes. In box-1, the uniaxial tensile strain along thedirection influences the formation and migration energies of thedumbbell but slightly affects the migration energy of a single vacancy. In box-2, the uniaxial tensile strain along thedirection influences the formation and migration energies of both vacancy and interstitials. Especially, adumbbell has a lower migration energy when its migration direction is the same or close to the strain direction, while along these directions, a vacancy has a higher migration energy. All these results indicate that the uniaxial tensile strain can result in the anisotropic formation and migration energies of simple defects in materials. [ABSTRACT FROM AUTHOR]

Published
2017
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49. H-ion Irradiation-induced Annealing in He-ion Implanted 4H-SiC.

Author

Yi Han, Bing-Sheng Li, Zhi-Guang Wang, Jin-Xin Peng, Jian-Rong Sun, Kong-Fang Wei, Cun-Feng Yao, Ning Gao, Xing Gao, Li-Long Pang, Ya-Bin Zhu, Tie-Long Shen, Hai-Long Chang, Ming-Huan Cui, Peng Luo, Yan-Bin Sheng, Hong-Peng Zhang, Xue-Song Fang, Si-Xiang Zhao, and Jin Jin

Subjects
HYDROGEN ions, ANNEALING of crystals, HELIUM ions, ION implantation, SILICON carbide, RAMAN spectroscopy
Abstract

Radiation-induced defect annealing in He+ ion-implanted 4H-SiC via H+ ion irradiation is investigated by Raman spectroscopy. There are 4H-SiC wafers irradiated with 230 keV He+ ions with fluences ranging from cm−2 to cm−2 at room temperature. The post-implantation samples are irradiated by 260 keV H+ ions at a fluence of cm−2 at room temperature. The intensities of Raman lines decrease after He implantation, while they increase after H irradiation. The experimental results present that the magnitude of Raman line increment is related to the concentration of pre-existing defects formed by He implantation. A strong new peak located near 966 cm−1, which is assigned to 3C-SiC LO () phonon, is found in the He-implanted sample with a fluence of cm−2 followed by H irradiation. However, for the He-implanted sample with a fluence of cm−2 followed by H irradiation, no 3C-SiC phonon vibrations are found. The detailed reason for H irradiation-induced phase transformation in the He-implanted 4H-SiC is discussed. [ABSTRACT FROM AUTHOR]

Published
2017
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50. Effect of Strain Field on Threshold Displacement Energy of Tungsten Studied by Molecular Dynamics Simulation.

Author

Dong Wang, Ning Gao, W. Setyawan, R. J. Kurtz, Zhi-Guang Wang, Xing Gao, Wen-Hao He, and Li-Long Pang

Subjects
*TUNGSTEN, *STRAINS & stresses (Mechanics), *MOLECULAR dynamics, *POTENTIAL theory (Physics), *ISOSTATIC pressing
Abstract

The influence of strain field on defect formation energy and threshold displacement energy (Ed) in body-centered cubic tungsten (W) is studied with molecular dynamics simulation. Two different W potentials (Fikar and Juslin) are compared and the results indicate that the connection distance and selected function linking the short-range and long-range portions of the potentials affect the threshold displacement energy and its direction-specific values. The minimum Ed direction calculated with the Fikar potential is 〈100〉 and with the Juslin potential is 〈111〉. Nevertheless, the most stable self-interstitial configuration is found to be a 〈111〉-crowdion for both the potentials. This stable configuration does not change with the applied strain. Varying the strain from compression to tension increases the vacancy formation energy while decreases the self-interstitial formation energy. The formation energy of a self-interstitial changes more significantly than a vacancy such that Ed decreases with the applied hydrostatic strain from compression to tension. [ABSTRACT FROM AUTHOR]

Published
2016
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