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Warm deformation behavior and work-softening mechanism of Fe- 6.5wt.%Si alloy

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Journal of Iron and Steel Research International 2020年第3期27卷 342-354页

作者： Xiang-ju Shi yong-feng Liang Bin-bin Liu Bao Zhang feng Ye State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

Warm deformation behavior of the Fe-6.5wt.%Si alloy was studied by isothermal compression in the temperature range of 300-700℃.The results show that the influence of the ordered phases on the flow stress gradually weakens with increasing deformation *** flow stress of the furnace-cooled sample with the high degree of order at 300℃is higher than that of the quenched sample with the low degree of order,and the flow stresses of both samples are nearly the same at 500-700℃.The hardness difference between two samples deformed at 500℃gradually decreases with increasing strain,accompanying with a reduction in hardness of the furnace-cooled sample,which indicates a work-softening *** analyses of dislocation configurations and ordered structure suggest that the dynamic recovery and deformation-induced disorder result in the work-softening *** appropriate deformation temperature window for improving the formability of the Fe-6.5wt.%Si alloy is about 500-600℃.

关键词： Fe-6.5wt.%Si alloy Work softening Ordered structure Dynamic recovery Anti-phase boundary Dislocation

Lunar surface potential and electric field

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Research in Astronomy and Astrophysics 2019年第6期19卷 15-22页

作者： Lei Li Yi-Teng Zhang Bin Zhou yong-yong feng State Key Laboratory for Space Weather National Space Science Center Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

The Moon has no significant atmosphere, thus its surface is exposed to solar ultraviolet radiation and the solar wind. Photoemission and collection of the solar wind electrons and ions may result in lunar surface charging. On the dayside, the surface potential is mainly determined by photoelectrons, modulated by the solar wind;while the nightside surface potential is a function of the plasma distribution in the lunar wake. Taking the plasma observations in the lunar environment as inputs, the global potential distribution is calculated according to the plasma sheath theory, assuming Maxwellian distributions for the surface emitted photoelectrons and the solar wind electrons. Results show that the lunar surface potential and sheath scale length change versus the solar zenith angle, which implies that the electric field has a horizontal component in addition to the vertical one. By differentiating the potential vertically and horizontally, we obtain the global electric field. It is found that the vertical electric field component is strongest at the subsolar point,which has a magnitude of 1 V m-1. The horizontal component is much weaker, and mainly appears near the terminator and on the nightside, with a magnitude of several mV m-1. The horizontal electric field component on the nightside is rotationally symmetric around the wake axis and is strongly determined by the plasma parameters in the lunar wake.

关键词： Moon-planets and satellites surfaces-planets and satellites fundamental parameters-planets and satellites physical evolution

Obtaining exact value by approximate computations

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Science China Mathematics 2007年第9期50卷 1361-1368页

作者： Jing-zhong ZHANG yong feng Laboratory for Automated Reasoning and Programming Chengdu Institute of Computer ApplicationsChinese Academy of SciencesChengdu 610041China

Numerical approximate computations can solve large and complex problems *** have the advantage of high *** they only give approximate results,whereas we need exact results in some *** is a gap between approximate computations and exact results. In this paper,we build a bridge by which exact results can be obtained by numerical approximate computations.

关键词： numerical approximate computation symbolic-numerical computation continued fraction 33F10

五角星状ZrO_(2)改性聚酰亚胺的绝缘耐高温性能研究

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陕西科技大学学报 2024年第2期42卷 124-131页

作者：刘婉婉曹丽云冯永强成智文刘婷赵勇刘一军黄剑锋陕西科技大学材料科学与工程学院陕西省国际科技合作基地陕西西安710021 咸阳陶瓷研究设计院有限公司陕西咸阳712000 广东蒙娜丽莎集团有限公司广东佛山528211

新能源汽车工业的快速发展给汽车电机绝缘漆包线的耐温性能提出了更高要求,制备高性能且价格低廉的漆包线漆膜成为该领域的研究热点.本文提出用一步溶剂热法制备出五角星状ZrO_(2)纳米粉体,利用原位聚合法制备一种高性能、价格低廉的PI... 详细信息

新能源汽车工业的快速发展给汽车电机绝缘漆包线的耐温性能提出了更高要求,制备高性能且价格低廉的漆包线漆膜成为该领域的研究热点.本文提出用一步溶剂热法制备出五角星状ZrO_(2)纳米粉体,利用原位聚合法制备一种高性能、价格低廉的PI/五角星状ZrO_(2)复合薄膜.研究结果表明:制备的五角星状ZrO_(2)纳米粉体分布均匀,进而提高了ZrO_(2)在PI聚合物里的分散性;加入3%的五角星状ZrO_(2)纳米粉体后,相对于纯PI薄膜,PI/五角星状ZrO_(2)复合薄膜的疏水性能得到了提升,拉伸应力提高了4.8倍,初始热分解温度提高了8.30%,介电常数提高了3.2倍.可以看出,五角星状的ZrO_(2)对于纯PI薄膜绝缘、耐高温性能有显著提升.本工作对开发新型高性能漆包线新配方具有重要指导意义.

关键词：五角星状ZrO_(2) 聚酰亚胺复合薄膜绝缘耐高温

Joint spatial-frequency blind multiuser detection based on LCCMA

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The Journal of China Universities of Posts and Telecommunications 2007年第2期14卷 19-22页

作者： ZHAO Fa-yong feng Guang-zeng Department of Communication and Information Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China

Multicarrier code division multiple access （MC-CDMA） has the ability to combat with frequency selective fading and antenna array can enhance the performance of system. The paper proposes a novel joint spatial-frequency blind multiuser detection for antenna array MC-CDMA based on linear constraint constant modulation algorithm （LCCMA）, which has robust performance and can ensue the weight vectors to converge to that of the desired user Simulation indicates the proposed algorithm has better bit error ratio （BER） performance than that of the traditional beamforming-based two-step algorithm.

关键词： antenna array MC-CDMA LCCMA joint spatial-frequency blind multiuser detection

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一类双重退化四阶抛物型方程弱解的存在性

数学杂志 2024年第3期44卷 259-268页

作者：梁波李彬马永峰滁州学院数学与金融学院安徽滁州239000 大连交通大学理学院辽宁大连116028

本文主要研究了一类双重退化的四阶抛物方程弱解的存在性问题.首先,利用Galerkin理论与能量估计方法可以得到该问题在非退化边界情形下弱解的存在性.在此基础上,通过对正则化问题的解进行一致估计以及渐近极限的过程,获得边界退化情形... 详细信息

本文主要研究了一类双重退化的四阶抛物方程弱解的存在性问题.首先,利用Galerkin理论与能量估计方法可以得到该问题在非退化边界情形下弱解的存在性.在此基础上,通过对正则化问题的解进行一致估计以及渐近极限的过程,获得边界退化情形下弱解的存在性.

关键词：双重退化非线性抛物型方程边界退化存在性

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湖北省应急管理地方标准体系建设现状及对策

中国标准化 2024年第10期 62-68页

作者：潘恒王高锋万勇刘毅曹咏锋陈小路湖北省安全生产技术协会湖北省应急救援中心湖北兴发化工集团股份有限公司黄冈高新技术产业开发区管理委员会湖北省自然灾害应急技术中心

为逐步建立健全结构完善、层次清晰、分类科学的应急管理地方标准体系,本文结合湖北省实际,梳理了当前地方标准体系建设现状及省内外发展情况,总结了当前应急管理地方标准体系建设存在的一些问题,有针对性地提出下一步完善应急管理地方... 详细信息

为逐步建立健全结构完善、层次清晰、分类科学的应急管理地方标准体系,本文结合湖北省实际,梳理了当前地方标准体系建设现状及省内外发展情况,总结了当前应急管理地方标准体系建设存在的一些问题,有针对性地提出下一步完善应急管理地方标准体系化建设的对策建议,为今后标准化制修订工作规划提供参考和技术支撑。

关键词：应急管理地方标准体系建设

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Long-term continuous energy injection in the afterglow of GRB 060729

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Research in Astronomy and Astrophysics 2009年第12期9卷 1317-1323页

作者： Ming Xu yong-feng Huang Tan Lu Department of Astronomy Nanjing University Nanjing 210093 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China

A long plateau phase and an amazing level of brightness have been observed in the X-ray afterglow of GRB 060729. This peculiar light curve is likely due to longterm energy injection in external shock. Here, we present a detailed numerical study of the energy injection process of magnetic dipole radiation from a strongly magnetized millisecond pulsar and model the multi-band afterglow observations. It is found that this model can successfully explain the long plateaus in the observed X-ray and optical afterglow light curves. The sharp break following the plateaus could be due to the rapid decline of the emission power of the central pulsar. At an even later time （～ 5×10^6 s）, an obvious jet break appears, which implies a relatively large half opening angle of θ ～ 0.3 for the GRB ejecta. Due to the energy injection, the Lorentz factor of the outflow is still larger than two even at 10^7 s after the GRB trigger, making the X-ray afterglow of this burst detectable by Chandra even 642 d after the burst.

关键词： gamma rays: bursts -- ISM: jets and outflows

Autonomous maneuver decision-making for a UCAV in short-range aerial combat based on an MS-DDQN algorithm

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Defence Technology（防务技术） 2022年第9期18卷 1697-1714页

作者： yong-feng Li Jing-ping Shi Wei Jiang Wei-guo Zhang yong-xi Lyu School of Automation Northwestern Polytechnical UniversityXi'an 710129China Shaanxi Province Key Laboratory of Flight Control and Simulation Technology Xi'an 710129China

To solve the problem of realizing autonomous aerial combat decision-making for unmanned combat aerial vehicles(UCAVs) rapidly and accurately in an uncertain environment, this paper proposes a decision-making method based on an improved deep reinforcement learning(DRL) algorithm: the multistep double deep Q-network(MS-DDQN) algorithm. First, a six-degree-of-freedom UCAV model based on an aircraft control system is established on a simulation platform, and the situation assessment functions of the UCAV and its target are established by considering their angles, altitudes, environments, missile attack performances, and UCAV performance. By controlling the flight path angle, roll angle, and flight velocity, 27 common basic actions are designed. On this basis, aiming to overcome the defects of traditional DRL in terms of training speed and convergence speed, the improved MS-DDQN method is introduced to incorporate the final return value into the previous steps. Finally, the pre-training learning model is used as the starting point for the second learning model to simulate the UCAV aerial combat decision-making process based on the basic training method, which helps to shorten the training time and improve the learning efficiency. The improved DRL algorithm significantly accelerates the training speed and estimates the target value more accurately during training, and it can be applied to aerial combat decision-making.

关键词： Unmanned combat aerial vehicle Aerial combat decision Multi-step double deep Q-network Six-degree-of-freedom Aerial combat maneuver library