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Optimization of extrusion process parameters of Incoloy028 alloy based on hot compression test and simulation

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Transactions of Nonferrous Metals Society of China 2017年第11期27卷 2464-2473页

作者： Zhi-qiang YU Gen-shu ZHOU lei-feng tuo Cong-fei SONG State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University Xi’an 710049 China Stainless Steel Tube Branch Company Taiyuan Iron & Steel (Group) Co. Ltd. Taiyuan 030003 China

True stress?true strain curves of Incoloy028alloy at high temperature and strain rate were investigated by hot compression *** curves show that the maximum flow stress decreases with the increase in temperature and the decrease in strain *** simulation was employed to investigate the influence of temperature,extrusion speed and friction coefficient on the extrusion load,stress,strain and strain rate in the extrusion *** increase of extrusion temperature results in decrease of load and deformation resistance,but has little influence on strain and strain *** extrusion speed changes between200and350mm/s,no obvious change about extrusion load can be *** peak value up to42500kN emerges in the extrusion load curve and the extrusion process becomes unstable seriously when extrusion speed rises up to400mm/*** stress and strain rate increase with the raise of extrusion *** friction coefficient is between0.02and0.03,deformation resistance is about160MPa and the strain rate can be limited below70s?*** production of Incoloy028tube verifies the optimized parameters by FEM simulation analysis,and mechanical tests results of the products meet the required properties.

关键词： Incoloy028 alloy hot extrusion compression process parameter FEM simulation

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具有逆向边增长结构LT码的设计与分析

电子学报 2022年第5期50卷 1201-1210页

作者：宋鑫程乃平廖育荣倪淑燕雷拓峰航天工程大学研究生院北京101416 航天工程大学电子与光学工程系北京101416

为了解决传统卢比变换(Luby Transform,LT)码在加性高斯白噪声(Additive White Gaussian Noise,AWGN)信道中存在高误码平台的问题,提出了一种具有逆向边增长(Reverse Edge Growth,REG)结构的LT码.REG-LT码会标记度数值相对较小的信息节... 详细信息

为了解决传统卢比变换(Luby Transform,LT)码在加性高斯白噪声(Additive White Gaussian Noise,AWGN)信道中存在高误码平台的问题,提出了一种具有逆向边增长(Reverse Edge Growth,REG)结构的LT码.REG-LT码会标记度数值相对较小的信息节点,并使其逆向精准地选取足够数量的校验节点,从而获得不低于期望目标的度数值.首先,设计了REG-LT码的编码算法,分析了校验节点和信息节点的选取原则.其次,推导了REG-LT码的信息节点度分布和校验节点度分布的数学表达式,分析了REG-LT码的收敛性.最后,引入增益损失比(Gain Loss Ratio,GLR)以衡量参数T;对收敛性的影响,将最大化GLR作为求解最优T;值的设计原则.仿真结果表明,与传统LT码相比,本文的REG-LT码可将误码平台降低3至5个数量级,且至少可获得2 dB的编码增益;此外,REG-LT码也能够实现优于现有LT码的误比特率(Bit Error Rate,BER)性能.

关键词：喷泉码 LT码高斯信道误比特率度分布编码算法外信息传递图

低度数值信息节点可按序消除的卢比变换编码算法

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科学技术与工程 2021年第26期21卷 11176-11183页

作者：程乃平宋鑫廖育荣倪淑燕雷拓峰航天工程大学电子与光学工程系北京101400 航天工程大学研究生院北京101400

为了解决传统卢比变换(Luby transform,LT)码在加性高斯白噪声(additive white gaussian noise,AWGN)信道中存在误码平台的问题,提出了一种改进的编码算法。该算法引入阈值筛选出度数值相对较小的信息节点,并使这些节点优先参与编码过程... 详细信息

为了解决传统卢比变换(Luby transform,LT)码在加性高斯白噪声(additive white gaussian noise,AWGN)信道中存在误码平台的问题,提出了一种改进的编码算法。该算法引入阈值筛选出度数值相对较小的信息节点,并使这些节点优先参与编码过程;阈值可变且递增,进而达到了按序消除不可靠信息节点的目的。首先,分析了低度数值信息节点对误码平台的影响,设计了阈值递增的节点按序消除编码算法。其次,给出了改进算法的理论误比特率(bit error rate,BER)下界,分析了不同参数对算法BER性能的影响。最后,分析了改进算法对LT码收敛性的影响,并指出了算法参数的选取原则。仿真结果显示,与传统LT码相比,改进算法能够将误码平台降低近3个数量级;此外,改进算法也能够实现优于参考文献LT码的BER性能,验证了算法的可行性。

关键词：信道编码卢比变换码误比特率收敛性阈值

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稀疏码分多址技术发展及前景

科学技术与工程 2023年第5期23卷 1789-1798页

作者：雷拓峰倪淑燕崔亮程乃平宋鑫陈世淼航天工程大学研究生院北京101416 航天工程大学电子与光学工程系北京101416 66407部队北京100144

提升频谱资源利用率是未来移动通信亟待解决的一项重要目标。其中,稀疏码分多址(sparse code multiple access,SCMA)技术具备频谱利用率高、抗干扰性能力强、系统兼容性好等优点,已成为一种非常有前景的非正交多址方案。为了在未来移动... 详细信息

提升频谱资源利用率是未来移动通信亟待解决的一项重要目标。其中,稀疏码分多址(sparse code multiple access,SCMA)技术具备频谱利用率高、抗干扰性能力强、系统兼容性好等优点,已成为一种非常有前景的非正交多址方案。为了在未来移动通信中进一步发展稀疏码分多址技术,综述了现有稀疏码分多址技术的研究成果,对其研究现状进行了总结分析。首先,分析了现有的码本设计方案,指出了其设计特点以及目前尚存在的问题,并给出相应的解决方案;其次,在解码算法方面,给出了目前两种常见的解码算法,简述了其基本原理,并介绍了一些新兴的解码算法;再次,就SCMA技术与其他技术结合而言,从3个方面总结了目前SCMA技术的研究成果,并探讨了SCMA技术在应用层面潜在的发展的方向;最后,总结了稀疏码分多址技术的发展挑战和趋势。

关键词：稀疏码分多址技术码本设计解码算法稀疏码分多址应用

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溴化镧闪烁体探测器性能及应用研究（英文）

光谱学与光谱分析 2017年第7期37卷 2298-2304页

作者：张海薇王磊冷逢庆庹先国刘明哲成毅姚付良李三刚赵柏俊卢位地质灾害防治与地质环境保护国家重点实验室(成都理工大学) 四川成都610059 成都理工大学核技术与自动化工程学院四川成都610059 四川理工学院四川自贡643000

LaBr3(Ce)探测器是一种新型闪烁体探测器,具有高光产额,高探测效率,高时间和空间分辨率,高能量分辨率,温度特性良好,抗辐射性能良好,操作简便等优点。从2001年以来,该探测器得到了迅速的研究和应用。LaBr3(Ce)探测器在核共振荧光检测、... 详细信息

LaBr3(Ce)探测器是一种新型闪烁体探测器,具有高光产额,高探测效率,高时间和空间分辨率,高能量分辨率,温度特性良好,抗辐射性能良好,操作简便等优点。从2001年以来,该探测器得到了迅速的研究和应用。LaBr3(Ce)探测器在核共振荧光检测、瞬发γ中子活化分析、爆炸物检测、核医学成像、环境辐射监测、空间辐射探测等方面的应用研究中取得了非常良好的效果。该探测器表现出优于以往用于这些领域的探测器的性能(例如NaI(Tl)探测器、BGO探测器、HPGe探测器等)。介绍了LaBr3(Ce)探测器的性能及其应用研究进展,对代表性文献进行了简析和综述,阐明了其良好的应用前景。

关键词： LaBr3(Ce)探测器能量分辨率探测效率瞬发γ中子活化分析核共振荧光分析

Advances in the Development of Gradient Scaffolds Made of Nano-Micromaterials for Musculoskeletal Tissue Regeneration

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NANO-MICRO LETTERS 2025年第1期17卷 1-46页

作者： Fang, lei Lin, Xiaoqi Xu, Ruian Liu, Lu Zhang, Yu Tian, feng Li, Jiao Jiao Xue, Jiajia Beijing Univ Chem Technol Beijing Lab Biomed Mat Beijing 100029 Peoples R China Beijing Univ Chem Technol State Key Lab Organ Inorgan Composites Beijing 100029 Peoples R China Univ Technol Sydney Fac Engn & IT Sch Biomed Engn Sydney NSW 2007 Australia

This review highlights the gradient variations in the structural composition of musculoskeletal tissues and comprehensively examines recent progress in the fabrication and application of biomimetic gradient scaffolds for musculoskeletal *** challenges and prospects of gradient scaffolds for clinical application are discussed. The intricate hierarchical structure of musculoskeletal tissues, including bone and interface tissues, necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes. This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes. Building on the anatomical characteristics of bone and interfacial tissues, this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues, specifically focusing on methods used to construct compositional and structural gradients within the scaffolds. The latest applications of gradient scaffolds for the regeneration of bone, osteochondral, and tendon-to-bone interfaces are presented. Furthermore, the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed, as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.

关键词： Gradient scaffolds Musculoskeletal tissues Advanced manufacturing Biomaterials Tissue regeneration

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非正交多址接入技术及其应用研究

通信技术 2020年第9期53卷 2093-2100页

作者：雷拓峰程乃平倪淑燕张爱迪航天工程大学电子与光学工程系北京101416 航天工程大学研究生院北京101416

简要阐述非正交多址接入(Non-orthogonal Multiple Access,NOMA)技术的发展,分析认知无线电在NOMA多址技术中的应用。具体地,主要论述5G中NOMA的相关技术,介绍几种典型的NOMA相关方案,并进一步分析了MIMO-NOMA技术,证明了NOMA技术具备... 详细信息

简要阐述非正交多址接入(Non-orthogonal Multiple Access,NOMA)技术的发展,分析认知无线电在NOMA多址技术中的应用。具体地,主要论述5G中NOMA的相关技术,介绍几种典型的NOMA相关方案,并进一步分析了MIMO-NOMA技术,证明了NOMA技术具备很好的兼容性。最后,分析目前商业通信卫星的发展,并对NOMA在卫星通信中的应用进行了相关分析。

关键词：非正交多址 5G 认知无线电卫星通信

Ferroptosis in ischemic stroke:Animal models and mechanisms

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Zoological Research 2024年第6期45卷 1235-1248页

作者： Qing-Zhang tuo Peng lei Department of Geriatrics and State Key Laboratory of Biotherapy National Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityChengduSichuan 610041China Department of Neurology and State Key Laboratory of Biotherapy National Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityChengduSichuan 610041China

Stroke is a major cause of death and disability worldwide,with the majority of cases resulting from ischemic events due to arterial *** therapeutic approaches focus on rapid reperfusion through intravenous thrombolysis and intravascular *** these interventions can mitigate long-term disability,reperfusion itself may induce neuronal *** exact mechanisms underlying neuronal damage following cerebral ischemia have yet to be *** research suggests that ferroptosis may play a significant role in post-ischemic neuronal death,which can be targeted to prevent neuronal *** review explores the three essential hallmarks of ferroptosis:the presence of redox-active iron,the peroxidation of polyunsaturated fatty acid-containing phospholipids,and the loss of lipid peroxide repair *** involvement of ferroptosis in neuronal injury following ischemic stroke is also explored,along with an overview of ferroptosis-associated changes in different ischemic stroke animal ***,recent therapeutic interventions targeting the ferroptosis pathway,as well as the opportunities,difficulties,and future directions of ferroptosis-targeted therapies in ischemic stroke,are discussed.

关键词： Ischemic stroke Ferroptosis Animal models Iron deposition Lipid peroxidation

Computing the Determinant of a Matrix with Polynomial Entries by Approximation

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Journal of Systems Science & Complexity 2018年第2期31卷 508-526页

作者： QIN Xiaolin SUN Zhi LENG tuo feng Yong Department of Mathematics Sichuan University Chengdu 610064 China Chengdu Institute of Computer Applications Chinese Academy of Sciences Chengdu 610041 China Chengdu Institute of Computer Applications Chinese Academy of Sciences Chengdu 610041 China. School of Computer Engineering and Science Shanghai University Shanghai 200444 China.

Computing the determinant of a matrix with the univariate and multivariate polynomial entries arises frequently in the scientific computing and engineering fields. This paper proposes an effective algorithm to compute the determinant of a matrix with polynomial entries using hybrid symbolic and numerical computation. The algorithm relies on the Newton＇s interpolation method with error control for solving Vandermonde systems. The authors also present the degree matrix to estimate the degree of variables in a matrix with polynomial entries, and the degree homomorphism method for dimension reduction. Furthermore, the parallelization of the method arises naturally.

关键词： Approximate interpolation dimension reduction error controllable algorithm symbolicdeterminant Vandermonde systems.