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Stability and Electronic Properties of Hydrogenated Zigzag Carbon Nanotube Focused on Stone-Wales Defect
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作者 潘立军 张洁 +1 位作者 陈卫光 唐亚楠 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第3期82-86,共5页
We present a first-principles study of the chemisorption of hydrogen on a Stone-Wales (SW) defective carbon nanotube (10,0). The investigated configurations include four configurations covering single defects and ... We present a first-principles study of the chemisorption of hydrogen on a Stone-Wales (SW) defective carbon nanotube (10,0). The investigated configurations include four configurations covering single defects and double defects. One hydrogen dimer adsorption is energetically favored on bonds shared by carbon heptagon-heptagon for configurations with the defect parallel to the tube axis compared with the carbon pentagon-hexagon sites for ones with a slanted defect. This different behavior is also demonstrated for hydrogen dimer chain adsorption, the favored site for the former ones is through the defect, which is the nearest neighbor site to defect for the latter ones. It is found that the energy band gaps of hydrogenated configurations may be enlarged or decreased by altering the adsorption site or defect position. The semiconductor-to-metal transition may occur for configurations with the defect or defects parallel to the tube axis due to low electronic localization. Our results highlight the interest of the interaction of multi-factor system by providing a detailed bond and position picture of a hydrogenated defective carbon nanotube (10,0). 展开更多
关键词 SW stability and electronic Properties of Hydrogenated Zigzag Carbon Nanotube Focused on Stone-Wales Defect
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Structural Stability and Electronic Properties of the I41/amd Vanadium Dioxide
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作者 王成龙 刘光华 +1 位作者 陈颖 默广 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2017年第7期1055-1062,共8页
By using LDA+U approach based on the density functional theory, the structural stability of I41/amd VO2 is investigated. According to the phonon dispersion and stability criteria, the I41/amd is suggested to be anoth... By using LDA+U approach based on the density functional theory, the structural stability of I41/amd VO2 is investigated. According to the phonon dispersion and stability criteria, the I41/amd is suggested to be another possible and stable structure for the VO2. Lattice parameters of the I41/amd VO2 are determined by geometry optimization. The energy band structure shows that the I41/amd VO2 should be a metal. Furthermore, the upper valence band has dominant 2p-orbital characters, but the lower conduction band shows distinctive 3d-orbital characters. Obvious hybridization between the O-2p and V-3d orbitals is observed. 展开更多
关键词 structural stability electronic properties vanadium dioxide
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Electronic image stabilization system based on global feature tracking 被引量:7
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作者 Zhu Juanjuan Guo Baolong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第2期228-233,共6页
A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated ... A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated from the local motions of selected feature points. Considering the local moving objects or the inevitable mismatch, the matching validation, based on the stable relative distance between the points set is proposed, thus maintaining high accuracy and robustness. Next, the global motion parameters are accumulated for correction by Kalman filteration. The experimental result illustrates that the proposed system is effective to stabilize translational, rotational, and zooming jitter and robust to local motions. 展开更多
关键词 electronic image stabilization global motion estimation feature tracking Kalman filter.
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Vehicular Electronic Image Stabilization System Based on a Gasoline Model Car Platform 被引量:1
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作者 Ning Zhang Yuan Yang +2 位作者 Jianhua Wu Ziqian Zhao Guodong Yin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2022年第6期351-362,共12页
Noise,vibration and harshness(NVH)problems in vehicle engineering are always challenging in both traditional vehicles and intelligent vehicles.Although high accuracy manufacturing,modern structural roads and advanced ... Noise,vibration and harshness(NVH)problems in vehicle engineering are always challenging in both traditional vehicles and intelligent vehicles.Although high accuracy manufacturing,modern structural roads and advanced suspension technology have already significantly reduced NVH problems and their impacts;off-road condition,obstacles and extreme operating condition could still trigger NVH problems unexpectedly.This paper proposes a vehicular electronic image stabilization(EIS)system to solve the vibration problem of the camera and ensure the environment perceptive function of vehicles.Firstly,feature point detection and matching based on an oriented FAST and rotated BRIEF(ORB)algorithm are implemented to match images in the process of EIS.Furthermore,a novel improved random sampling consensus algorithm(i-RANSAC)is proposed to eliminate mismatched feature points and increase the matching accuracy significantly.And an adaptive Kalman filter(AKF)is applied to improve the adaptability of the vehicular EIS.Finally,an experimental platform based on a gasoline model car was established to validate its performance.The experimental results show that the proposed EIS system can satisfy vehicular performance requirements even under off-road condition with obvious obstacles. 展开更多
关键词 electronic image stabilization Environment perceptive function Feature point Adaptive Kalman filter Gasoline model car
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Thermionic Electron Emission Stability of Mo-La_2O_3 Cathode
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作者 周文元 张久兴 +3 位作者 刘燕琴 万小峰 周美玲 左铁镛 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第3期395-398,共4页
The carbonizing process and its influence on the thermionic electron emission properties of Mo-La_2O_3 cathode materials were investigated. The carbonized temperature, carbonized time and the pressure of C_6H_6 are ke... The carbonizing process and its influence on the thermionic electron emission properties of Mo-La_2O_3 cathode materials were investigated. The carbonized temperature, carbonized time and the pressure of C_6H_6 are key factors of the carbonizing process. The carbonized ratio of Mo-La_2O_3 cathode increases with the increase of carbonizing temperature at low temperature. The highest carbonized ratio is 19.7% obtained at 1723 K, then the carbonized ratio decreases rapidly if temperature increases further. The carbonized ratio increases with the prolongation of carbonizing time during the process of first 6 min., after that the carbonization ratio changes little with the time increase, and the carbonized ratio increases with the increase of the C_6H_6 pressure when the pressure is low, the maximum carbonized ratio reaches 19.7% at 1.5×10^(-2) Pa, then the carbonized ratio goes down sharply when the C_6H_6 pressure is over 1.5×10^(-2) Pa. The emission properties at different operated temperatures and the emission current stability of FU-6051 tubes (equipped) with Mo-La_2O_3 cathodes were also studied in the article. The study results indicate that the emission can keep stable only when the operating temperature is from 1700 to 1800 K and the carbonized layer must be composed by Mo_2C only. The FU-6051 tubes (equipped) with Mo-La_2O_3 cathodes have excellent stable emission current and the lifetime exceeds 3000 h when the cathode′s carbonized ratio is 19.7% operated at 1773 K. 展开更多
关键词 Mo-La_2O_3 cathode electron emission stability carbonizing LIFETIME rare earths
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Electronic stabilization of catadioptric panoramic image
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作者 马子领 王建中 《Journal of Beijing Institute of Technology》 EI CAS 2011年第2期238-243,共6页
An effective algorithm of electronic image stabilization (EIS) of catadioptric panoramic imaging system for track robots is presented. The key techniques of this algorithm are as follows:① A model of electronic im... An effective algorithm of electronic image stabilization (EIS) of catadioptric panoramic imaging system for track robots is presented. The key techniques of this algorithm are as follows:① A model of electronic image stabilization is built by analyzing the imaging theory and the principle of EIS, and the image shift function of unwrapped panoramic image is deduced;② The relationship equation between motion estimation parameters of annular panoramic image and motion estimation parameters of unwrapped panoramic image is developed according to the constrained aspect ratio of real objects, motion parameters of annular panoramic image are firstly estimated, and then motion parameters among the image shift function are carried out according to the relationship equation;③ An excessive stabilization threshold is presented to prevent the phenomena of excessive stabilization, and the Kalman filtering is adopted to smooth the image sequences. Numerical experimental results show that this algorithm can effectively smooth out the unwanted motion and follow the intentional camera movement under certain resolutions. 展开更多
关键词 catadioptric panoramic imaging electronic image stabilization Kalman filtering
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PHOTOEMISSION STABILITY OF MULTIALKALI PHOTOCATHODES WITH NEGATIVE ELECTRON AFFINITY
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作者 Tailiang Guo Huairong. Gao Physics Department of Fuzhou University, Fujian 350002, China 《真空科学与技术学报》 EI CAS CSCD 1992年第Z1期231-234,共4页
In this paper a negative electron affinity (NEA) multialkali photocathode of (Na<sub>2</sub>KSb-Cs)-O-Cs structure is fabricated by new technology. It is found that its emission stability is much bette... In this paper a negative electron affinity (NEA) multialkali photocathode of (Na<sub>2</sub>KSb-Cs)-O-Cs structure is fabricated by new technology. It is found that its emission stability is much better than that of the NEA GaAs photocathode, but is inferior to that of the conventional Na<sub>2</sub>KSb(Cs). After 70 hour performance in a pumping vacuum system, the emission sensitivity of the NEA (Na<sub>2</sub>KSb-Cs)-O-Cs photocathode drops only by 2.5%. The emission stability is closely related to the states of the activation cesium and oxygen during activation, best results being obtained with cesium ions and excited oxygen. Furthermore, better photoemission sensitivity and emission stability may be obtained if the cathode is illuminated by intense white light during the activation process. The performance of the NEA (Na<sub>2</sub>KSb-Cs)-O-Cs cathode which has not been illuminated by intense white light during activation may be improved by the illumination even during operation intermission. 展开更多
关键词 NEA THAN CS PHOTOEMISSION stability OF MULTIALKALI PHOTOCATHODES WITH NEGATIVE ELECTRON AFFINITY
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Vehicle path tracking by integrated chassis control 被引量:10
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作者 Saman Salehpour Yaghoub Pourasad Seyyed Hadi Taheri 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第4期1378-1388,共11页
The control problem of trajectory based path following for passenger vehicles is studied. Comprehensive nonlinear vehicle model is utilized for simulation vehicle response during various maneuvers in MATLAB/Simulink. ... The control problem of trajectory based path following for passenger vehicles is studied. Comprehensive nonlinear vehicle model is utilized for simulation vehicle response during various maneuvers in MATLAB/Simulink. In order to follow desired path, a driver model is developed to enhance closed loop driver/vehicle model. Then, linear quadratic regulator(LQR) controller is developed which regulates direct yaw moment and corrective steering angle on wheels. Particle swam optimization(PSO) method is utilized to optimize the LQR controller for various dynamic conditions. Simulation results indicate that, over various maneuvers, side slip angle and lateral acceleration can be reduced by 10% and 15%, respectively, which sustain the vehicle stable. Also, anti-lock brake system is designed for longitudinal dynamics of vehicle to achieve desired slip during braking and accelerating. Proposed comprehensive controller demonstrates that vehicle steerability can increase by about 15% during severe braking by preventing wheel from locking and reducing stopping distance. 展开更多
关键词 vehicle dynamics active control system optimal controller electronic stability program(ESP) particle swam optimization(PSO)
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Real-time digital image stabilization based on regional field image gray projection 被引量:4
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作者 Weiping Yang Zhilong Zhang +3 位作者 Yan Zhang Xinping Lu Jicheng Li Zhiguang Shi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第1期224-231,共8页
Digital image stabilization technique plays important roles in video surveillance and object acquisition.Many useful electronic image stabilization algorithms have been studied.A real-time algorithm is proposed based ... Digital image stabilization technique plays important roles in video surveillance and object acquisition.Many useful electronic image stabilization algorithms have been studied.A real-time algorithm is proposed based on field image gray projection which enables the regional odd and even field image to be projected into x and y directions and thus to get the regional gray projection curves in x and y directions,respectively.For the odd field image channel,motion parameters can be estimated via iterative minimum absolute difference based on two successive field image regional gray projection curves.Then motion compensations can be obtained after using the Kalman filter method.Finally,the odd field image is adjusted according to the compensations.In the mean time,motion compensation is applied to the even field image channel with the odd field image gray projection curves of the current frame.By minimizing absolute difference between odd and even field image gray projection curves of the current frame,the inter-field motion parameters can be estimated.Therefore,the even field image can be adjusted by combining the inter-field motion parameters and the odd field compensations.Finally,the stabilized image sequence can be obtained by synthesizing the adjusted odd and even field images.Experimental results show that the proposed algorithm can run in real-time and have a good stabilization performance.In addition,image blurring can be improved. 展开更多
关键词 image dithering field based processing electronic image stabilization regional gray projection minimum absolute difference.
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Effects of the precipitation of stabilizers on the mechanism of grain fracturing in a zirconia metering nozzle 被引量:2
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作者 Liang Zhao Qun-hu Xue Dong-hai Ding 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第9期1041-1047,共7页
The mechanism of grain fracturing in a zirconia metering nozzle used in the continuous casting process was studied. The phase composition, microstructure, and chemical composition of the residual samples were studied ... The mechanism of grain fracturing in a zirconia metering nozzle used in the continuous casting process was studied. The phase composition, microstructure, and chemical composition of the residual samples were studied using an X-ray fluorescence analyzer, scanning electron microscope, and electron probe. Results revealed that the composition, structure, and mineral phase of the original layer, transition layer, and affected layer of the metering nozzle differed because of stabilizer precipitation and steel slag permeation. The stabilizer MgO formed low-melting phases with steel slag and impure SiO2 on the boundaries(pores) of zirconia grains; consequently, grain fracturing occurred and accelerated damage to the metering nozzle was observed. 展开更多
关键词 continuous casting metering nozzle partially stabilized zirconia grains fracture mechanisms electron probe microanalysis
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Structural Modification of Al65Cu16.5Ti18.5 Amorphous Powder through Annealing and Post Milling: Improving Thermal Stability 被引量:1
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作者 Zhen Tan Lu Wang +2 位作者 Yunfei Xue Xingwang Cheng Long Zhang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2016年第12期1326-1331,共6页
To improve thermal stability of the Al65Cu16.5Ti18.5 amorphous powder,structural modification of the amorphous powder was performed through annealing and post milling.Annealing above the crystallization temperature(T... To improve thermal stability of the Al65Cu16.5Ti18.5 amorphous powder,structural modification of the amorphous powder was performed through annealing and post milling.Annealing above the crystallization temperature(Tx) not only induced nanoscale intermetallics to precipitate in the amorphous powder,but also increased Cu atomic percentage within the residual amorphous phase.Post milling induced the amorphization of the nanocrystal intermetallics and the formation of Cu9Al4 from the residual amorphous phase.Thus,a mixed structure consisting of amorphous phase and Cu9Al4 was obtained in the powder after annealing and post milling(the APMed powder).The phase constituent in the APMed powder did not change during the post annealing,which exhibited significantly improved thermal stability in comparison with the as-milled amorphous powder. 展开更多
关键词 Amorphous powder Thermal stability Heat treatment Mechanical alloying Transmission electron microscopy
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Appending triphenyltriazine to 1,10-phenanthroline: a robust electron-transport material for stable organic light-emitting diodes 被引量:5
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作者 Guang Jin Jun-Zhe Liu +7 位作者 Jian-Hua Zou Xiao-Lan Huang Meng-Jiao He Ling Peng Ling-Ling Chen Xu-Hui Zhu Junbiao Peng Yong Cao 《Science Bulletin》 SCIE EI CSCD 2018年第7期446-451,共6页
There has been an increasing demand for high-performance and cost-effective organic electron-transport materials for organic light-emitting diodes (OLEDs). In this contribution, we present a simple compound 3-(3-(... There has been an increasing demand for high-performance and cost-effective organic electron-transport materials for organic light-emitting diodes (OLEDs). In this contribution, we present a simple compound 3-(3-(4,6-diphenyl-l,3,5-triazin-2-yl)phenyl)-1,10-phenanthroline through the facile Pd-catalyzed coupling of a triphenyltriazine boronic ester with 3-hromo-1,10-phenanthroline. It shows a high Tg of 112℃. The ultraviolet photoelectron spectroscopy measurements reveal a deep HOMO level of -6.5 eV. The LUMO level is derived as -3.0 eV, based on the optical bandgap. The low-temperature solid-state phosphorescent spectrum gives a triplet energy of -2.36eV. n-Doping with 8-hydroxyquinolatolithium (Liq, 1:1) leads to considerably improved electron mobility of 5.2 × 10 -6 -5.8 × 10 -5 cm2 v-1 S-1 at E=(2-5) × 10 5Vcm -1, in contrast with the triarylphosphine oxide- phenantroline molecular conjugate we reported previously. It has been shown that through optimizing the device structure and hence suppressing polaron-exciton annihilation, introducing this single Liq-doped electron-transport layer could offer high-efficiency and stable phosphorescent OLEDs. 展开更多
关键词 Electron transport materials Organic light-emitting diodes Phenanthroline Device stability Triazine
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Generation of high-quality electron beams from a laser-based advanced accelerator
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作者 Ahmed M.M.Elsied Nasr A.M.Hafz +3 位作者 李松 Mohammad Mirzaie Thomas Sokollik 张杰 《Chinese Physics C》 SCIE CAS CSCD 2015年第6期98-103,共6页
At Shanghai Jiao Tong University(SJTU) we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wake... At Shanghai Jiao Tong University(SJTU) we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wakefield acceleration(LWFA) scheme, multi-hundred Me V electron beams of reasonable quality are generated using 20–40 TW, 30 femtosecond laser pulses interacting independently with helium, neon, nitrogen and argon gas jet targets. The laser-plasma interaction conditions are optimized for stabilizing the electron beam generation from each type of gas. The electron beam pointing angle stability and divergence angle as well as the energy spectra from each gas jet are measured and compared. 展开更多
关键词 accelerator pointing helium acceleration divergence interacting hundred independently Electron stabilizing
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