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Structure and property of metal melt Ⅳ——Evolution of titanium melt residual bond structure and its effect on dynamic viscosity

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science China(Physics,Mechanics & Astronomy) 2012年第8期55卷 1371-1375页

作者： MI GuangBao CAO JingXia HUANG Xu CAO ChunXiao LIPeiJie HE LiangJu Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys Beijing Institute of Aeronautical Materials Beijing 100095 China National Center afNovel Materials for International Research Tsinghua University Beijing 100084 China

Based on the concept of melt residual bonds, a calculating model quantitatively describing the evolution of the residual bond structure of titanium melt at the melting point or in a certain range above the melting point was established; i.e., both the size ds and the bond number n of the residual bond structure decrease monotonously with the increase of temperature. By mathe- matical deduction, a linear relationship between the residual bond structure size ds and the dynamic viscosity 17 of Titanium melt was revealed, i.e., η= 0.876 ＋ 0.471·ds, which is of great significance to the investigation of the relationship between the melt microstructure and the macroscopic properties of metals with high melting temperature.

关键词： titanium melt residual bond structure dynamic viscosity calculating model

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Outer delocalized electron aggregation of bromide bridged core–shell CuBr@C for hydrogen evolution reaction

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Nano Research 2023年第5期16卷 6608-6614页

作者： Tianyi Xu Ruoyu Li Lei Zhang Dongxu Jiao Yilong Dong Ming Gong Dantong Zhang Jinchang Fan Dewen Wang Yanhua Liu Xiao Zhao Wei Zhang Weitao Zheng Xiaoqiang Cui State Key Laboratory of Automotive Simulation and Control School of Materials Science and EngineeringKey Laboratory of Automobile Materials of MOEJilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy MaterialsElectron Microscopy CenterJilin UniversityChangchun 130012China College of Chemistry Jilin UniversityChangchun 130012China Center of Multiscale Crystal Materials Research Institute of Advanced Materials Science and EngineeringShenzhen Intitute of Advanced TechnologyChinese Academy of ScienceShenzhen 518055China

Modulation of the surface electron distribution is a challenging problem that determines the adsorption ability of catalytic ***,we address this challenge by bridging the inner and outer layers of the core–shell structure through the bridge Br *** shell wrapped copper bromide nanorods(CuBr@C)are constructed for the first time by chemical vapour deposition with hexabromobenzene(HBB).HBB pyrolysis provides both bridge Br atom and C *** C shell protects the stability of the internal halide structure,while the bridge Br atom triggers the rearrangement of the surface electrons and exhibits excellent electrocatalytic ***,the hydrogen evolution reaction(HER)activity of CuBr@C is significantly better than that of commercial N-doped carbon nanotubes,surpassing commercial Pt/C at over 200 mA·cm^(−2).Density functional theory(DFT)calculations reveal that bridge Br atoms inspire aggregation of delocalized electrons on C-shell surfaces,leading to optimization of hydrogen adsorption energy.

关键词： bridge Br atoms delocalized electron aggregation core–shell nanorods C-shell wrapped CuBr hydrogen evolution reaction

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Influence of Alloying Elements Content on High Temperature Properties of Ti-V-Cr and Ti-Al-V Series Titanium Alloys: A JMatPro Program Calculation Study

Influence of Alloying Elements Content on High Temperature P...

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Chinese Materials Conference 2022-2023

作者： Sun, Ruochen Mi, Guangbao Aviation Key Laboratory of Science and Technology on Advanced Titanium Alloys AECC Beijing Institute of Aeronautical Materials Beijing100095 China

For the issues of high temperature performance affected by the alloying elements content in Ti-V-Cr and Ti-V-Cr alloys, the thermodynamic calculation method based on JMatPro program was applied in this study. The research is mainly focused on the analysis of phase composition, thermodynamic parameters and mechanical properties of Ti-Al-V and Ti-V-Cr series alloys with different element proportions under high temperature environment. Those obtained results show that the proportion of Al in Ti-Al-V alloys has a great influence on the high temperature properties. Increasing the content of Al not only increases the transformation temperature of β single-phase structure and delays the transformation process of α/β microstructure to β single-phase structure, but also helps to improve the high temperature thermal conductivity and elastic deformation resistance of the alloy. In Ti-V-Cr alloys, the influence of V element on high temperature properties is mainly focused on the improvement of thermal conductivity and high temperature deformation properties, while the influence of Cr element is relatively weak. Besides, adding a small amount of Al element to Ti-V-Cr alloy can further improve the thermal conductivity of the alloy. The Young's modulus of the Ti-V-Cr alloy increases when 0.3%-1% of C element is added. Finally, the effect of Si element on the high temperature elastic deformation of the alloy is relatively weak. © Published under licence by IOP Publishing Ltd.

关键词： Titanium alloys

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Recent progress in friction stir welding tools used for steels

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Journal of Iron and Steel Research International 2018年第5期25卷 477-486页

作者： Lei Cui Chao Zhang Yong-chang Liu Xiu-guo Liu Dong-po Wang Hui-jun Li Tianjin Key Laboratory of Advanced Joining Technology School of Materials Science and Engineering Tianjin University Tianjin 300354 China State Key Lab of Hydraulic Engineering Simulation andSafety School of Materials Science and Engineering TianjinUniversity Tianjin 300354 China Faculty of Engineering and Information Sciences Universityof Wollongong Wollongong 2522 NSW Australia

Friction stir welding （FSW） technology is being increasingly attractive in welding steels on account of the high-quality weld formation and excellent weld properties. The feasibility of FSW of steels has been convinced for nearly 20 years. However, the application progress for FSW of steels is slower than that of aluminum alloys owing to the high cost and poor usability of tools. The FSW tools are called as the heart of FSW process which is critical for welding quality control and the weld microstructure and properties. The recent progresses in research and development of FSW tools for welding steels have been reviewed. Material selections, geometry parameters, wear behavior and use life of the tools are summarized from the available literatures.

关键词： Friction stir welding Steel FSW process Tool material Tool design Tool wear behavior

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Semi-supervised Open-set Recognition of Radar Active Jamming

Semi-supervised Open-set Recognition of Radar Active Jamming

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2021 CIE International Conference on Radar, Radar 2021

作者： Li, Hao Fang, Xueli Zhang, Lei Kang, Hui Zhang, Wei School of Information and Communication Engineering University of Electronic Science and Technology of China Chengdu China Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (纸本)9781665498142

With the emergence of various kinds of complex radar jamming, radar jamming intelligent recognition technology has increasingly become the key to electronic counter-counter measures. To achieve radar jamming open-set recognition with a small number of tagged samples, Generative adversarial network-based pseudolabeled convolutional neural network (GAN-PL-CNN) model is proposed in this paper. Firstly, radar jamming is modelled, and the radar jamming datasets with known and unknown types are established after time-frequency transformation and image processing. Then, the adaptive pseudolabeling method is used to achieve semi-supervised recognition of radar jamming by combining the learning capability of convolutional neural networks and the characteristics of pseudolabeling to increase labeled samples intelligently. Finally, generative adversarial networks are introduced to enhance the recognition ability of the model and the discrimination ability of the unknown type through the game between the generator and the discriminator in the iterative process. Experimental results show that the GAN-PL-CNN model achieves 89.7%-95.1% for known types and 30.7%-86.8% for unknown types at 3%-6% labeling rate. As the number of labeled samples increases, the recognition effect becomes better and has a greater ability to exclude unknown type. © 2021 IEEE.

关键词： convolutional neural network open-set recognition pseudo-label Radar active jamming

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Radar Signal Modulation Recognition Based on Bispectrum Features and Deep learning 2

Radar Signal Modulation Recognition Based on Bispectrum Feat...

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2nd International Conference on Computer Engineering and Application, ICCEA 2021

作者： Dong, Zeyu Lv, Fengrong Wan, Tao Jiang, Kaili Fang, Xueli Zhang, Lei University of Electronic Science and Technology of China School of Information and Communication Engineering Chengdu China Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (纸本)9781665426169

Signal bispectral transformation can not only suppress the influence of Gaussian white noise on signal modulation recognition, but also retain the signal amplitude and phase information. It is also used to extract the non-linear characteristics. Compared with other high-order spectra, bispectrum has a simple processing flow. However, the direct use of all bispectrum as signal features will lead to two-dimensional template matching, causing lots of calculations. Converting two-dimensional bispectrum into one-dimensional sequence, for example, extracting slice information of bispectrum, or using integral bispectrum apparently reduce the amount of data to be processed while retaining part of the bispectrum information. We input the extracted bispectral transformation of radar signals into the neural network to realize modulation recognition. The simulations validate our conclusions that our proposed methods still have a high recognition probability while SNR is low. © 2021 IEEE.

关键词： Template matching

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Radar Signal Detection Based on Ambiguity Function and Deep Learning 2

Radar Signal Detection Based on Ambiguity Function and Deep ...

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2nd International Conference on Computer Engineering and Application, ICCEA 2021

作者： Lv, Fengrong Dong, Zeyu Wan, Tao Jiang, Kaili Fang, Xueli Zhang, Lei University of Electronic Science and Technology of China School of Information and Communication Engineering Chengdu China Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (纸本)9781665426169

The ambiguity function describes the joint characteristics of the signal in the time domain and the frequency domain, and is usually used for signal recognition. The time domain and frequency domain distribution of noise is more spurious than the signal. Its ambiguity function can also reflect its characteristics. However, the direct use of the ambiguity function as the signal feature will increase the amount of calculation of the detection system, so slice it, which reduces the burden on the system for detecting signal information while preserving the information. At the same time, the radar signal detection based on neural network can avoid the influence of artificially setting the threshold on the detection performance of the system. So, we propose an algorithm for inputting the extracted fuzzy function slice sequence into a neural network to realize signal detection. simulation proves that when the signal-To-noise ratio of the received signal is very low, our proposed method still has a high detection probability. © 2021 IEEE.

关键词： Signal detection

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Multi-View Subspace Clustering Via Simultaneously Cycle Projection and Similarity Learning 21

Multi-View Subspace Clustering Via Simultaneously Cycle Proj...

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21st International Computer Conference on Wavelet Active Media technology and Information Processing, ICCWAMTIP 2024

作者： Tao, Xiang Jie, Liu Wenshen, Qiao Siying, Xiao Mao, Ye Southwest China Institute of Electronic Technology National Key Laboratory of Complex Aviation System Simulation Chengdu610036 China University of Electronic Science and Technology of China Chengdu611731 China

ISBN: (纸本)9798331519254

At present, most of the existing methods combine the data from different views mechanically to obtain the latent subspace with complementary information, which not only fails to make full use of the data information from specific perspectives but also brings redundancy. Therefore, we propose a novel multi-view subspace clustering method. It utilizes cycle projection to obtain a subspace construction model. At the same time, by learning the global structure and local manifold structure of this subspace while assigning learnable weights to different views, the consensus information among views and specific information from different views are captured according to the importance of different views. In this way, our method effectively reduces the original noise and redundancy, and further carries out the improvement of complementarity and consistency among views. The proposed method is optimized by using the Augmented Lagrangian Multiplier with Alternating Direction Minimization (ALM- ADM) algorithm. Experiment results on benchmark datasets confirm the effectiveness of our method. © 2024 IEEE.

关键词： Contrastive Learning

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Cooperative jamming resource allocation based on integer-encoded directed mutation artificial bee colony algorithm 4

Cooperative jamming resource allocation based on integer-enc...

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4th IEEE International Conference on Electronic Information and Communication technology, ICEICT 2021

作者： Xia, Jiechen Ma, Jing Li, Yibing Song, Mingzhao Harbin Engineering University Harbin150001 China Key Laboratory of Advanced Marine Communication and Information Technology Ministry of Industry and Information Technology Science and Technology on Special System Simulation Laboratory Beijing100854 China

ISBN: (纸本)9781665432030

Electromagnetic countermeasure (ECM) is of extreme importance in modern warfare. In order to confront the threat of radar-net, cooperative jamming platform with multiple jammers is the main approach. A proper allocation of jamming resource is required before and during the process of interference. This paper proposes an artificial bee colony (ABC) based jamming resource allocation (JRA) algorithm with few parameter adjustments. The allocation strategy is encoded in integer to better handle the constraints of JRA problem. Furthermore, a genetic algorithm (GA) inspired solution update method is introduced in stages of algorithm to accelerate the convergence rate. simulation result shows that the proposed algorithm has a better performance in both rate and precision of convergence compared with tabu search artificial bee colony algorithm (TSABC) and ant colony optimization algorithm (ACO), which were adopted in previous related studies. ©2021 IEEE

关键词： Tabu search

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Compensation method of GPS signal delay based on factor graph 4

Compensation method of GPS signal delay based on factor grap...

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4th IEEE International Conference on Electronic Information and Communication technology, ICEICT 2021

作者： Chen, Hangyu Ma, Jing Ye, Fang Harbin Engineering University Harbin150001 China Key Laboratory of Advanced Marine Communication and Information Technology Ministry of Industry and Information Technology Science and Technology on Special System Simulation Laboratory Beijing100854 China

ISBN: (纸本)9781665432030

In recent years, unmanned ground vehicles (UGVs) have been widely used in urban environments. The satellite positioning system plays an irreplaceable role in UGVs. However, the tall buildings in cities may cause interference to the transmission of satellite signals, which results in positioning delays, thus reducing the positioning accuracy of UGVs. To address this issue, a compensation method for information delay based on factor graph model is proposed in this paper. In the factor graph model utilized, the corresponding GPS factor node will not be generated when the GPS signal delay occurs at the current fusion time. The subsequent factor graph model is directly generated by the combined navigation system of visual odometry (VO) and inertial measurement unit (IMU). When the delayed GPS signal arrives, the measurement data of VO and IMU are used to compensate the delayed GPS positioning information. The compensated GPS positioning information is used to generate an additional factor node at the moment when the GPS signal actually arrives. This additional factor node is connected into the factor graph model for data fusion so that the delayed GPS positioning information can still be used to correct the positioning error. The method proposed in this paper effectively reduces the positioning error while taking into account the real-time performance. Experimental simulations show that the proposed method can reduce the positioning error while GPS signal delay occurs. ©2021 IEEE

关键词： Global positioning system

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