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Microstructural evolution and restoration of creep property for a damaged K403 alloy after rejuvenation heat treatments

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Rare Metals 2021年第7期40卷 1865-1871页

作者： Liang Wang Xiao-Guang Yang Hong-Yu Qi Duo-Qi Shi Shao-Lin Li School of Energy and Power Engineering Beihang UniversityBeijing 100191China Beijing Key Laboratory of Aero-Engine Structure and Strength Beijing 100191China

Rejuvenation heat treatments can restore the microstructures and mechanical properties of the degraded turbine blades in gas turbine engines.Herein we analyze the effects of rejuvenation heat treatments on the microstructural characteristics and mechanical properties of damaged and undamaged specimens of a Ni-based superalloy,K403.The damaged specimens were found to have degraded microstructures and shorter creep lifetime than the undamaged specimen.The rejuvenation heat treatment proved beneficial,especially for specimens exposed to damage for 50 h.In addition,the microstructure recovery and creep life were found to depend on the predamage durations of the specimens.A y’-precipitate-based creep lifetime model was established to predict the residual lifetime based on the microstructural information.

关键词： Microstructural evolution Creep property restoration Rejuvenation heat treatments

Load Shedding and restoration for Intentional Island with Renewable Distributed Generation

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Journal of Modern Power Systems and Clean Energy 2021年第3期9卷 612-624页

作者： Jian Xu Boyu Xie Siyang Liao Zhiyong Yuan Deping Ke Yuanzhang Sun Xiong Li Xiaotao Peng the School of Electrical Engineering and Automations Wuhan UniversityWuhan 430072China the China Southern Power Grid Research Institute China Southern Power Grid CompanyGuangzhou 510663China

Due to the high penetration of renewable distributed generation(RDG),many issues have become conspicuous during the intentional island operation such as the power mismatch of load shedding during the transition process and the power imbalance during the restoration process.In this paper,a phase measurement unit(PMU)based online load shedding strategy and a conservation voltage reduction(CVR)based multi-period restoration strategy are proposed for the intentional island with RDG.The proposed load shedding strategy,which is driven by the blackout event,consists of the load shedding optimization and correction table.Before the occurrence of the large-scale blackout,the load shedding optimization is solved periodically to obtain the optimal load shedding plan,which meets the dynamic and steady constraints.When the blackout occurs,the correction table updated in real time based on the PMU data is used to modify the load shedding plan to eliminate the power mismatch caused by the fluctuation of RDG.After the system transits to the intentional island seamlessly,multi-period restoration plans are generated to optimize the restoration performance while maintaining power balance until the main grid is repaired.Besides,CVR technology is implemented to restore more loads by regulating load demand.The proposed load shedding optimization and restoration optimization are linearized to mixed-integer quadratic constraint programming(MIQCP)models.The effectiveness of the proposed strategies is verified with the modified IEEE 33-node system on the real-time digital simulation(RTDS)platform.

关键词： Intentional island renewable distributed generation(RDG) load shedding restoration phase measurement unit(PMU) conservation voltage reduction(CVR)

Review of Service restoration for Distribution Networks

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Journal of Modern Power Systems and Clean Energy 2020年第1期8卷 1-14页

作者： Feifan Shen Qiuwei Wu Yusheng Xue Center for Electric Power and Energy Department of Electrical EngineeringTechnical University of DenmarkLyngbyDenmark State Grid Electric Power Research Institute NanjingChina

With the rapid deployment of the advanced metering infrastructure(AMI)and distribution automation(DA),selfhealing has become a key factor to enhance the resilience of distribution networks.Following a permanent fault occurrence,the distribution network operator(DNO)implements the selfhealing scheme to locate and isolate the fault and to restore power supply to out-of-service portions.As an essential component of self-healing,service restoration has attracted considerable attention.This paper mainly reviews the service restoration approaches of distribution networks,which requires communication systems.The service restoration approaches can be classified as centralized,distributed,and hierarchical approaches according to the communication architecture.In these approaches,different techniques are used to obtain service restoration solutions,including heuristic rules,expert systems,metaheuristic algorithms,graph theory,mathematical programming,and multi-agent systems.Moreover,future research areas of service restoration for distribution networks are discussed.

关键词： Distribution networks fault detection fault isolation service restoration self-healing scheme

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新闻微阅读四篇

疯狂英语（初中天地） 2024年第7期 56-63页

作者：王燕不详

China and France will cooperate on the restoration of Notre-Dame Cathedral,中法将联合修复巴黎圣母院,The Emperor Qinshihuang’s Mausoleum[陵墓;陵园]Site Museum in northwestern China announced that it will collaborate with its French counterpart on the restoration[修复]of Notre-Dame Cathedral in Paris and the protection of the Terracotta Warriors.

关键词：微阅读 northwestern restoration

Real-time restoration of rotational blurred image using gradient-loading

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Chinese Optics Letters 2008年第5期6卷 334-337页

作者：韩超阳李建勋陈萧朱振幅 Department of Automation Shanghai Jiao Tong University Optical Signature of Targets and Environments Key Laboratory of National Defense Science and Technology

The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix. Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image. By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then. Gradient- loading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading. Compared with the approach using least square filtering, its peak signal-to-noise ratio （PSNR） is improved from 3.18 to 6.46 dB, while the computing time is reduced to 1/2 - 1/3. Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.

关键词： Chlorine compounds Constrained optimization Curve fitting Degradation Geodesy Least squares approximations Repair restoration Signal to noise ratio

Semi-blind image restoration based on Chan-Vese denoising model

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Chinese Optics Letters 2008年第6期6卷 405-407页

作者：王智峰唐延东 State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of Sciences

A semi-blind image restoration algorithm is proposed based on reduced non-convex approximation of Luminita Vese and Tony Chan＇s （C-V） denoising model. Compared with C-V denoising model, we modify the fidelity term and add a term on point spread function （PSF）. The function depends on two variables： the image function to be restored u and the standard deviation of Gaussian kernel to be estimated a. Then the problems consist in solving a system with two coupled equations. Compared with the Leah Bar＇s semi-blind image restoration model which must solve three coupled equations, our method only needs to solve two equations. Furthermore, the estimation of f by our algorithm is superior to Leah Bar＇s algorithm. The experimental results demonstrate that the proposed method is effective.

关键词： Boolean functions Computer networks Image reconstruction Optical transfer function Repair restoration

Hopfield neural network-based image restoration with adaptive mixed-norm regularization

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Chinese Optics Letters 2009年第8期7卷 686-689页

作者：许元男刘丽萍赵远靳辰飞孙秀冬 Department of Physics Harbin Institute of Technology

To overcome the shortcomings of traditional image restoration model and total variation image restoration model, we propose a novel Hopfield neural network-based image restoration algorithm with adaptive mixed-norm regularization. The new error function of image restoration combines the L2-norm and L1- norm regularization types. A method of calculating the adaptive scale control parameter is introduced. Experimental results demonstrate that the proposed algorithm is better than other algorithms with single norm regularization in the improvement of signal-to-noise ratio （ISNR） and vision effect.

关键词： Communication channels (information theory) Control system analysis Hopfield neural networks Image reconstruction Neural networks restoration Signal to noise ratio

Mountain tunnel under earthquake force:A review of possible causes of damages and restoration methods

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第2期12卷 414-426页

作者： Xuepeng Zhang Yujing Jiang Kazuhiko Maegawa State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and TechnologyQingdao266590China School of Engineering Nagasaki UniversityNagasaki8528521Japan Nippon Expressway Research Institute Company Limited Tokyo194-8508Japan

Accurate seismic assessment and proper aseismic design of underground structures require a comprehensive understanding of seismic performance and response of underground structures under earthquake force.In order to understand the seismic behavior of tunnels during an earthquake,a wide collection of case histories has been reviewed from the available literature with respect to damage classification,to discuss the possible causes of damage,such as earthquake parameters,structural form and geological conditions.In addition,a case of Tawarayama tunnel subjected to the 2016 Kumamoto earthquake is studied.Discussion on the possible influence factors aims at improving the performancebased aseismic design of tunnels.Finally,restoration design criterion and methods are presented taking Tawarayama tunnel as an example.

关键词： Mountain tunnel Seismic damage Influence factor restoration method

Active-fault-alarm based pre-restoration mechanism in MPLS-TP optical network

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The Journal of China Universities of Posts and Telecommunications 2010年第3期17卷 97-103页

作者： BAI Hui-feng, LU Yue-ming, JI Yue-feng Key Laboratory of Information Photonics and Optical Communications, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing 100876, China Key Laboratory of Information Photonics and Optical Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

The newly developed multi-protocol label switching transport profile （MPLS-TP） fails to actively alarm the fault in advance when conducting restoration in network, or to avoid the false-alarm when equipped with the active-fault-alarm （AFA） to support carrier-grade reliability. In order to solve this problem, a new AFA based pre-restoration mechanism （AFABPRM） is proposed for MPLS-TP controlled optical network, along with the three levels quality-of-service （QoS） based shortest path first rerouting algorithm （TQ-SPF） in this article. The AFABPRM takes full advantage of the AFA technologies, and can solve the false-alarm problem. Analytical and experimental results suggest the better performances of the new mechanism when compared restoration mechanism with or without AFA function, and show that the AFABPRM can solve the false-alarm problem efficiently.

关键词： MPLS-TP restoration AFA