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Multi-layer multi-pass friction rolling additive manufacturing of Al alloy:Toward complex large-scale high-performance components

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 425-438页

作者： Haibin Liu Run Hou Chenghao Wu Ruishan Xie Shujun Chen College of Mechanical&Energy Engineering Beijing University of TechnologyBeijing 100124China Chongqing Research Institute of Beijing University of technology Chongqing 401121China

At present,the emerging solid-phase friction-based additive manufacturing technology,including friction rolling additive man-ufacturing(FRAM),can only manufacture simple single-pass *** this study,multi-layer multi-pass FRAM-deposited alumin-um alloy samples were successfully prepared using a non-shoulder tool *** material flow behavior and microstructure of the over-lapped zone between adjacent layers and passes during multi-layer multi-pass FRAM deposition were studied using the hybrid 6061 and 5052 aluminum *** results showed that a mechanical interlocking structure was formed between the adjacent layers and the adja-cent passes in the overlapped center *** friction and rolling of the tool head led to different degrees of lateral flow and plastic deformation of the materials in the overlapped zone,which made the recrystallization degree in the left and right edge zones of the over-lapped zone the highest,followed by the overlapped center zone and the non-overlapped *** tensile strength of the overlapped zone exceeded 90%of that of the single-pass deposition *** is proved that although there are uneven grooves on the surface of the over-lapping area during multi-layer and multi-pass deposition,they can be filled by the flow of materials during the deposition of the next lay-er,thus ensuring the dense microstructure and excellent mechanical properties of the overlapping *** multi-layer multi-pass FRAM deposition overcomes the limitation of deposition width and lays the foundation for the future deposition of large-scale high-performance components.

关键词： aluminum alloy additive manufacturing solid-state friction stir welding multi-layer multi-pass

Decoherence in optimized quantum random-walk search algorithm

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Chinese Physics B 2015年第8期24卷 197-202页

This paper investigates the effects of decoherence generated by broken-link-type noise in the hypercube on an optimized quantum random-walk search algorithm. When the hypercube occurs with random broken links, the optimized quantum random-walk search algorithm with decoherence is depicted through defining the shift operator which includes the possibility of broken links. For a given database size, we obtain the maximum success rate of the algorithm and the required number of iterations through numerical simulations and analysis when the algorithm is in the presence of decoherence. Then the computational complexity of the algorithm with decoherence is obtained. The results show that the ultimate effect of broken-link-type decoherence on the optimized quantum random-walk search algorithm is negative.

关键词： quantum search algorithm quantum random walk decoherence

Passive decoy-state quantum key distribution using weak coherent pulses with modulator attenuation

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Chinese Physics B 2015年第11期24卷 118-124页

作者：李源鲍皖苏李宏伟周淳汪洋 Zhengzhou information science and technology Institute Synergetic Innovation center of Quantum information and Quantum Physics University of Science and Technology of China

Passive decoy-state quantum key distribution is more desirable than the active one in some scenarios. It is also affected by the imperfections of the devices. In this paper, the influence of modulator attenuation on the passive decoy-state method is considered. We introduce and analyze the unbalanced Mach-Zehnder interferometer, briefly, and combining with the virtual source and imaginary unitary transformation, we characterize the passive decoy-state method using a weak coherent photon source with modulator attenuation. According to the attenuation parameter 6, the pass efficiencies are given. Then, the key generation rate can be acquired. From numerical simulations, it can be seen that modulator attenuation has a non- negligible influence on the performance of passive-state QKD protocol. Based on the research, the analysis method of virtual source and imaginary unitary transformation are preferred in analyzing passive decoy state protocol, and the passive decoy-state method is better than the active one and is close to the active vacuum ＋ weak decoy state under the condition of having the same modulator attenuation.

关键词： quantum key distribution passive decoy state modulator attenuation weak coherent pulses

Effects of systematic phase errors on optimized quantum random-walk search algorithm

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Chinese Physics B 2015年第6期24卷 155-163页

This study investigates the effects of systematic errors in phase inversions on the success rate and number of iterations in the optimized quantum random-walk search algorithm. Using the geometric description of this algorithm, a model of the algorithm with phase errors is established, and the relationship between the success rate of the algorithm, the database size, the number of iterations, and the phase error is determined. For a given database size, we obtain both the maximum success rate of the algorithm and the required number of iterations when phase errors are present in the algorithm. Analyses and numerical simulations show that the optimized quantum random-walk search algorithm is more robust against phase errors than Grover＇s algorithm.

关键词： quantum search algorithm quantum random walk phase errors robustness

Stimulated Brillouin scattering-induced phase noise in an interferometric fiber sensing system

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Chinese Physics B 2012年第3期21卷 256-261页

作者：陈伟孟洲周会娟罗洪 Department of Optic information science and technology College of Optoelectronic Science and EngineeringNational University of Defense Technology

Stimulated Brillouin scattering-induced phase noise is harmful to interferometric fiber sensing systems. The localized fluctuating model is used to study the intensity noise caused by the stimulated Brillouin scattering in a single-mode fiber. The phase noise structure is analyzed for an interferometric fiber sensing system, and an unbalanced Michelson interferometer with an optical path difference of 1 m, as well as the phase-generated carrier technique, is used to measure the phase noise. It is found that the phase noise is small when the input power is below the stimulated Brillouin scattering threshold, increases dramatically at first and then gradually becomes flat when the input power is above the threshold, which is similar to the variation in relative intensity noise. It can be inferred that the increase in phase noise is mainly due to the broadening of the laser linewidth caused by stimulated Brillouin scattering, which is verified through linewidth measurements in the absence and presence of the stimulated Brillouin scattering.

关键词： stimulated Brillouin scattering phase noise interferometric fiber sensing intensity noise

Phase-matching analysis of four-wave mixing induced by modulation instability in a single-mode fiber

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Chinese Physics B 2012年第9期21卷 332-337页

作者：陈伟孟洲周会娟 Department of Optic information science and technology College of Optoelectronic Science and EngineeringNational University of Defense Technology

Four-wave mixing induced by modulation instability in a single-mode fiber is analyzed from the phase-matching point of view. For the two-channel transmission, a method is proposed to select the four-wave-mixing-induced sidebands, which is based on the proper use of a continuous-wave and a pulse as light sources. We find that a mass of sidebands are generated in the modulation instability resonance region, and the power of the sideband increases with not only the peak power of the pump pulse but also the continuous-wave power which acts as a seed. The research will provide guidance for fiber communication and sensing systems using wavelength division multiplexing technology.

关键词： four-wave mixing modulation instability phase matching

Generalized Kibble-Zurek mechanism for defects formation in trapped ions

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science china(Physics,Mechanics & Astronomy) 2023年第8期66卷 20-25页

作者： Wei Wen Shanhua Zhu Yi Xie Baoquan Ou Wei Wu Pingxing Chen Ming Gong Guangcan Guo College of science Hunan University of TechnologyZhuzhou 412007China Institute for Quantum science and technology College of ScienceNational University of Defense TechnologyChangsha 410073China Hefei National Laboratory Hefei 230088China CAS Key Laboratory of Quantum information University of Science and Technology of ChinaHefei 230026China Synergetic Innovation center of Quantum information and Quantum Physics University of Science and Technology of ChinaHefei 230026China

The Kibble-Zurek(KZ)mechanism has played a fundamental role in defect formation with universal scaling laws in nonequilibrium phase ***,this theory may not accurately predict the scaling laws in inhomogeneous systems and slow quenching ***,we present a generalized KZ mechanism for the defect formation in trapped ions with the freeze-out condition gt=b0τ(t),where g is a universal quenching velocity function and b0 is a *** derived a differential equationφ(x,t)to account for the frozen correlation length of a kink in an inhomogeneous system and demonstrated a smooth crossover from a fast quenching process to a slow quenching process,which agrees well with the experiments performed by Ulm et al.[***.4,2290(2013)]and Pyka et al.[***.4,2291(2013)].Furthermore,we confirmed our theoretical model using molecular dynamics simulation by solving the stochastic differential equation,showing excellent agreement with the results from the differential *** theory provides a general theoretical framework for studying KZ physics in inhomogeneous systems,which has applications in other nonequilibrium platforms studied experimentally.

关键词： Kibble-Zurek mechanism trapped ions universal scaling law

同方期刊数据库

An OpenFlow-based performance-oriented multipath forwarding scheme in datacenters

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Frontiers of information technology & Electronic Engineering 2016年第7期17卷 647-660页

作者： Bo LIU Ming CHEN Bo XU Hui HU Chao HU Qing-yun ZUO Chang-you XING College of Command information Systems PLA University of Science and TechnologyNanjing 210007China PLA Academy of National defense information Wuhan 430020China

Although dense interconnection datacenter networks(DCNs)(e.g.,Fat Tree) provide multiple paths and high bisection bandwidth for each server pair,the widely used single-path Transmission Control Protocol(TCP)and equal-cost multipath(ECMP) transport protocols cannot achieve high resource utilization due to poor resource excavation and *** this paper,we present LESSOR,a performance-oriented multipath forwarding scheme to improve DCNs' resource *** adopting an Open Flow-based centralized control mechanism,LESSOR computes near-optimal transmission path and bandwidth provision for each flow according to the global network view while maintaining nearly real-time network view with the performance-oriented flow observing *** and comprehensive simulations show that LESSOR can efficiently improve the network throughput,which is higher than ECMP by 4.9%–38.3% under different *** also provides 2%–27.7% improvement of throughput compared with ***,LESSOR decreases the average flow completion time significantly.

关键词： Datacenter network Traffic engineering Open Flow Multipath transmission

Discovering Association Rules with Graph Patterns in Temporal Networks

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Tsinghua science and technology 2023年第2期28卷 344-359页

作者： Chu Huang Qianzhen Zhang Deke Guo Xiang Zhao Xi Wang science and technology on information Systems Engineering Laboratory College of Systems EngineeringNational University of Defense TechnologyChangsha 410073China

Discovering regularities between entities in temporal graphs is vital for many real-world applications(e.g.,social recommendation,emergency event detection,and cyberattack event detection).This paper proposes temporal graph association rules(TGARs)that extend traditional graph-pattern association rules in a static graph by incorporating the unique temporal information and *** introduce quality measures(e.g.,support,confidence,and diversification)to characterize meaningful TGARs that are useful and *** addition,the proposed support metric is an upper bound for alternative metrics,allowing us to guarantee a superset of *** extend conventional confidence measures in terms of maximal occurrences of *** diversification score strikes a balance between interestingness and *** the problem is NP-hard,we develop an effective discovery algorithm for TGARs that integrates TGARs generation and TGARs selection and shows that mining TGARs is feasible over a temporal *** propose pruning strategies to filter TGARs that have low support or cannot make top-k as early as ***,we design an auxiliary data structure to prune the TGARs that do not meet the constraints during the TGARs generation process to avoid conducting repeated subgraph matching for each extension in the search *** experimentally verify the effectiveness,efficiency,and scalability of our algorithms in discovering diversified top-k TGARs from temporal graphs in real-life applications.

关键词： temporal networks graph association rule subgraph pattern matching graph mining big graphs