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Schnurri-3 inhibition rescues skeletal fragility and vascular skeletal stem cell niche pathology in the OIM model of osteogenesis imperfecta
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作者 Na Li Baohong Shi +16 位作者 Zan Li Jie Han Jun Sun Haitao Huang Alisha R.Yallowitz Seoyeon Bok Shuang Xiao Zuoxing Wu Yu Chen Yan Xu Tian Qin Rui Huang Haiping Zheng Rong Shen Lin Meng Matthew B.Greenblatt Ren Xu 《Bone Research》 SCIE CAS CSCD 2024年第3期675-688,共14页
Osteogenesis imperfecta(OI)is a disorder of low bone mass and increased fracture risk due to a range of genetic variants that prominently include mutations in genes encoding typeⅠcollagen.While it is well known that ... Osteogenesis imperfecta(OI)is a disorder of low bone mass and increased fracture risk due to a range of genetic variants that prominently include mutations in genes encoding typeⅠcollagen.While it is well known that OI reflects defects in the activity of bone-forming osteoblasts,it is currently unclear whether OI also reflects defects in the many other cell types comprising bone,including defects in skeletal vascular endothelium or the skeletal stem cell populations that give rise to osteoblasts and whether correcting these broader defects could have therapeutic utility. 展开更多
关键词 SKELETAL imperfect ENDOtheLIUM
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Influence of manufacturing process-induced geometrical defects on the energy absorption capacity of polymer lattice structures
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作者 Alexandre Riot Enrico Panettieri +1 位作者 Antonio Cosculluela Marco Montemurro 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第5期47-59,共13页
Modern additive manufacturing processes enable fabricating architected cellular materials of complex shape,which can be used for different purposes.Among them,lattice structures are increasingly used in applications r... Modern additive manufacturing processes enable fabricating architected cellular materials of complex shape,which can be used for different purposes.Among them,lattice structures are increasingly used in applications requiring a compromise among lightness and suited mechanical properties,like improved energy absorption capacity and specific stiffness-to-weight and strength-to-weight ratios.A dedicated modeling strategy to assess the energy absorption capacity of lattice structures under uni-axial compression loading is presented in this work.The numerical model is developed in a non-linear framework accounting for the strain rate effect on the mechanical responses of the lattice structure.Four geometries,i.e.,cubic body centered cell,octet cell,rhombic-dodecahedron and truncated cuboctahedron 2+,are investigated.Specifically,the influence of the relative density of the representative volume element of each geometry,the strain-rate dependency of the bulk material and of the presence of the manufacturing process-induced geometrical imperfections on the energy absorption capacity of the lattice structure is investigated.The main outcome of this study points out the importance of correctly integrating geometrical imperfections into the modeling strategy when shock absorption applications are aimed for. 展开更多
关键词 Lattice structures Architected cellular materials Dynamic simulation Energy absorption Geometrical imperfection Additive manufacturing
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A coupled Legendre-Laguerre polynomial method with analytical integration for the Rayleigh waves in a quasicrystal layered half-space with an imperfect interface
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作者 Bo ZHANG Honghang TU +2 位作者 Weiqiu CHEN Jiangong YU L.ELMAIMOUNI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第9期1539-1556,共18页
The Laguerre polynomial method has been successfully used to investigate the dynamic responses of a half-space.However,it fails to obtain the correct stress at the interfaces in a layered half-space,especially when th... The Laguerre polynomial method has been successfully used to investigate the dynamic responses of a half-space.However,it fails to obtain the correct stress at the interfaces in a layered half-space,especially when there are significant differences in material properties.Therefore,a coupled Legendre-Laguerre polynomial method with analytical integration is proposed.The Rayleigh waves in a one-dimensional(1D)hexagonal quasicrystal(QC)layered half-space with an imperfect interface are investigated.The correctness is validated by comparison with available results.Its computation efficiency is analyzed.The dispersion curves of the phase velocity,displacement distributions,and stress distributions are illustrated.The effects of the phonon-phason coupling and imperfect interface coefficients on the wave characteristics are investigated.Some novel findings reveal that the proposed method is highly efficient for addressing the Rayleigh waves in a QC layered half-space.It can save over 99%of the computation time.This method can be expanded to investigate waves in various layered half-spaces,including earth-layered media and surface acoustic wave(SAW)devices. 展开更多
关键词 coupled Legendre-Laguerre polynomial method analytical integration Rayleigh wave quasicrystal(QC)layered half-space imperfect interface
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A Study on the Readings of Imperfective Aspect in English and Chinese
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作者 周梅 《海外英语》 2011年第8X期168-169,共2页
Smith (1997) proposes three stages of a situation from the imprefective veiwpoints in English: preliminary, internal and resultant stage and three readings of imperfective aspect. In the essay, the different readings ... Smith (1997) proposes three stages of a situation from the imprefective veiwpoints in English: preliminary, internal and resultant stage and three readings of imperfective aspect. In the essay, the different readings of imperfective aspect in English and Chinese will be explored. 展开更多
关键词 imperfective ASPECT PRELIMINARY READING PROGRESSIVE READING resultative READING
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Modeling of a DVB-S2 Transmission Chain with Optimization of Adjustment Parameters for a Good Quality of the Reception Signal
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作者 Patrick Dany Bavoua Kenfack Alphonse Binele Abana +1 位作者 Emmanuel Tonye Salim Adjiali Boukar 《International Journal of Communications, Network and System Sciences》 2023年第1期1-20,共20页
Digital television is part of our daily lives. We took an interest in the DVB-S2 standard in particular, because it is the one that governs the transmission by satellite of multimedia content from television programs.... Digital television is part of our daily lives. We took an interest in the DVB-S2 standard in particular, because it is the one that governs the transmission by satellite of multimedia content from television programs. With ever-changing user needs, there are new challenges that the DVB-S2 standard is no longer able to meet due to errors caused by weather and hardware limitations. The main purpose of a satellite TV transmission is to obtain a video signal in reception of the best possible quality and at a high bit rate. It is therefore important to determine all the factors which could intervene in the process of transmission and which have a negative impact on the yield at the reception of the signal. We therefore designed and simulated the DVB-S and DVB-S2 transmission chains with QPSK modulation (and an FEC coding rate of 1/2), on MATLAB software (Simulink), and with an AWGN channel for the sake of comparison performance between these two chains. Then we carried out the design of the DVB-S2 transmission chain with an RF (Radio Frequency) satellite channel, by materializing all the elements which intervene in the downlink to evaluate the performance of this chain according to the factors which influence and/or degrade the signal quality between transmission and reception at the receiving earth station. The main results obtained relate to the DVB-S2 transmission chain and were interpreted using the visualization of the error rate blocks: With an AWGN channel, increasing the signal-to-noise ratio decreases the rate of erroneous packets and therefore improves the quality of the received signal. With an RF satellite channel on the downlink: increasing the transmit power improves the receive performance, this is useful for correcting most RF imperfections;having larger parabolic antennas is an advantage because they have greater gains;this makes it possible to minimize the rate of erroneous packets. These simulations allowed us to determine the precise and numerical impact of RF degradations on the performance of the downlink DVB-S2 transmission chain. 展开更多
关键词 DVB-S2 MODULATION AWGN RF Imperfection TV Transmission
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Memristor Hypothesis in Malignant Charge Distribution
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作者 Andras Szasz 《Open Journal of Biophysics》 2023年第4期51-92,共42页
Tissues in biological objects from the point of view of electromagnetic effects must be modeled not only for their conductivity. The ionic double layer induced by the electric field, built by electrolytic diffusion, m... Tissues in biological objects from the point of view of electromagnetic effects must be modeled not only for their conductivity. The ionic double layer induced by the electric field, built by electrolytic diffusion, must be counted. The micro (frequency dispersion phenomena) and macro (interfacial polarization), as well as more generalized by Nernst-Planck cells describe the biophysical aspects of this phenomena. The charge distribution depends on the processes and produces charge gradients in space. The dynamic feasibility of the-charge transition layer has memory and adaptability, working like a memristor in cancerous development. The memristor processes may complete the adaptation mechanisms of cancer cells to extremely stressful conditions. Our objective is to show the distribution and redistribution of space charges that generate memristors and internal currents like injury current (IC) in the development of cancer. We show some connected aspects of the modulated electrohyperthermia (mEHT) limiting the proliferation process in the micro-range like the macro-range electrochemotherapy (ECT) processes do. The internal polarization effects form space-charge, which characteristically differ in malignant and healthy environments. The electrical resistivity of the electrolytes depends on the distribution of the charges and concentrations of ions in the electrolytes, consequently the space-charge differences appear in the conductivity parameters too. The polarization heterogeneities caused by the irregularities of the healthy tissue induce a current (called injury current), which appears in the cancerous tumor as well. Due to the nonlinearity of the space-charge production and the differences of the relaxation time of the processes in various subunits. The tumor develops the space-charge which appears as an inductive component in the otherwise capacitive setting and forms a memristive behavior of the tumorous tissue. This continuously developing space-charge accommodates the tumor to the permanently changing conditions and helps the adopting the malignant cells in the new environment. Applying external radiofrequency electric field, the disturbance of the space-charge may change the conditions, and seek to reestablish the healthy homeostatic equilibrium, blocking the pathologic injury current components. The hypothetical memristive behavior of the tumor microenvironment and the tumor mass may be a biophysical addition to the adaption mechanisms of tumor cell and could provide a way to block the pathogen biophysical processes. An electric field in the direction of the place of disturbance from the healthy neighborhood appears, starting a current, which promotes cell migrations and wound healing, re-establishing homeostatic equilibrium. In pathological disturbance, the same process starts, which supports further proliferation, so its blocking is desired. 展开更多
关键词 MALIGNANCY TUMORS MEMRISTOR Imperfect Dielectrics Heterogeneity Charge Distribution Injury Current Nernst-Planck Cell
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Joint Optimization of Imperfect Preventive Maintenance and Production Scheduling for Single Machine Based on Game Theory Method
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作者 Zuhua Jiang Jiawen Hu +2 位作者 Hongming Zhou Peiwen Ding Jiankun Liu 《Journal of Harbin Institute of Technology(New Series)》 CAS 2023年第4期15-24,共10页
In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department an... In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department and the maintenance department are minimized,respectively.Two kinds of three-stage dynamic game models and a backward induction method are proposed to determine the preventive maintenance(PM)threshold.A lemma is presented to obtain the exact solution.A comprehensive numerical study is provided to illustrate the proposed maintenance model.The effectiveness is also validated by comparison with other two existed optimization models. 展开更多
关键词 game theory imperfect preventive maintenance production scheduling single machine system
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Exploiting the Direct Link in IRS Assisted NOMA Networks with Hardware Impairments
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作者 Ziwei Liu Xinwei Yue +3 位作者 Shuo Chen Xuliang Liu Yafei Wang Wanwei Tang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第7期767-785,共19页
Hardware impairments(HI)are always present in low-cost wireless devices.This paper investigates the outage behaviors of intelligent reflecting surface(IRS)assisted non-orthogonal multiple access(NOMA)networks by takin... Hardware impairments(HI)are always present in low-cost wireless devices.This paper investigates the outage behaviors of intelligent reflecting surface(IRS)assisted non-orthogonal multiple access(NOMA)networks by taking into account the impact of HI.Specifically,we derive the approximate and asymptotic expressions of the outage probability for the IRS-NOMA-HI networks.Based on the asymptotic results,the diversity orders under perfect self-interference cancellation and imperfect self-interference cancellation scenarios are obtained to evaluate the performance of the considered network.In addition,the system throughput of IRS-NOMA-HI is discussed in delay-limited mode.The obtained results are provided to verify the accuracy of the theoretical analyses and reveal that:1)The outage performance and system throughput for IRS-NOMA-HI outperforms that of the IRS-assisted orthogonal multiple access-HI(IRS-OMA-HI)networks;2)The number of IRS elements,the pass loss factors,the Rician factors,and the value of HI are pivotal to enhancing the performance of IRS-NOMAHI networks;and 3)It is recommended that effective methods of reducing HI should be used to ensure system performance,in addition to self-interference cancellation techniques. 展开更多
关键词 Hardware impairments imperfect SIC intelligent reflecting surface non-orthogonal multiple access outage probability
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GB/T41972—2022《铸铁件铸造缺陷分类及命名》国家标准解读
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作者 丛建臣 孙军 +3 位作者 丛红日 冯梅珍 郭二军 王丽萍 《铸造》 CAS 2024年第3期428-436,共9页
介绍标准的制定过程和主要内容、与ISO/TR16078:2013标准的主要技术差异和标准的应用。结合铸造的实际生产过程,删除了部分非铸铁件出现的缺陷、不确定的缺陷或与其他内容重复的缺陷以及热处理缺陷,增加了部分生产中常见但标准中未能提... 介绍标准的制定过程和主要内容、与ISO/TR16078:2013标准的主要技术差异和标准的应用。结合铸造的实际生产过程,删除了部分非铸铁件出现的缺陷、不确定的缺陷或与其他内容重复的缺陷以及热处理缺陷,增加了部分生产中常见但标准中未能提及的缺陷,使其具有科学性和实用性。 展开更多
关键词 铸铁件 铸造缺陷 国家标准 解读
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基于明考斯基最优距离的不完美排错SRGM决策机制
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作者 张策 王金勇 +4 位作者 徐早辉 江文倩 白睿 李文毓 王建远 《郑州大学学报(理学版)》 CAS 北大核心 2024年第1期1-8,共8页
针对软件可靠性增长模型(software reliability growth model,SRGM)决策机制欠缺的问题,提出了基于明考斯基最优距离的不完美排错SRGM决策方法。首先,对真实软件测试过程与可靠性模型进行分析,建立分类视角下的SRGM归类集合;其次,从矩... 针对软件可靠性增长模型(software reliability growth model,SRGM)决策机制欠缺的问题,提出了基于明考斯基最优距离的不完美排错SRGM决策方法。首先,对真实软件测试过程与可靠性模型进行分析,建立分类视角下的SRGM归类集合;其次,从矩阵分析的角度形式化描述SRGM的评价与选择问题,建立基于明考斯基距离的双最优化排序方法;最后,对模型的性能进行综合评价,给出SRGM间的性能偏序关系。在4个实际计算机应用系统测试过程中记录并公开发表的失效数据集上进行实验,验证和阐释模型性能之间的排序机制效用,并进行参数敏感性分析,为模型决策提供定量化的参考。 展开更多
关键词 软件可靠性增长模型 不完美排错 决策机制 明考斯基距离
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NOMA增强型D2D组的鲁棒资源分配算法
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作者 彭艺 肖春娟 杨青青 《云南大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第3期443-451,共9页
为提高非正交多址接入(non-orthogonal multiple access,NOMA)增强型设备到设备(device-to-device,D2D)组链路的鲁棒性和能效,考虑非理想信道状态信息(channel station information,CSI),提出一种能效优化的鲁棒资源分配算法.首先,在保... 为提高非正交多址接入(non-orthogonal multiple access,NOMA)增强型设备到设备(device-to-device,D2D)组链路的鲁棒性和能效,考虑非理想信道状态信息(channel station information,CSI),提出一种能效优化的鲁棒资源分配算法.首先,在保证子信道分配、蜂窝用户和D2D组最小速率以及D2D组最大传输功率约束下,建立最大最小鲁棒能效模型;其次,考虑最坏情况法将信道不确定性建模为有界信道估计误差,并用泰勒级数展开式、凸松弛、变量转换法将原多变量耦合问题转化为凸优化问题;最后,用拉格朗日对偶理论求解.仿真结果表明,所提出的算法将传输速率控制在最低速率阈值以上,具有良好的鲁棒性,与其他算法相比能效提高了8.3%. 展开更多
关键词 设备到设备 非正交多址接入 非理想信道状态信息 鲁棒资源分配
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多用户全双工协作PNOMA系统非正交率控制及功率分配优化算法
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作者 申滨 张楠 董坤明 《电子学报》 EI CAS CSCD 北大核心 2024年第6期1842-1851,共10页
传统NOMA系统远近用户设备(User Equipment,UE)之间在时频资源上信号完全重叠,以期获得最高的频率利用率,但其中UE之间的干扰也成为核心问题之一.部分NOMA(Partial NOMA,PNOMA)系统由于仅在部分频段实现NOMA共存,因此可以优化协调UE之... 传统NOMA系统远近用户设备(User Equipment,UE)之间在时频资源上信号完全重叠,以期获得最高的频率利用率,但其中UE之间的干扰也成为核心问题之一.部分NOMA(Partial NOMA,PNOMA)系统由于仅在部分频段实现NOMA共存,因此可以优化协调UE之间的干扰.相较于传统NOMA系统,PNOMA系统能够极大地降低非理想连续干扰相消(imperfect Successive Interference Cancellation,ipSIC)对于系统和速率的消极影响.基于全双工协作NOMA(Full Duplex Cooperative NOMA,FD-CNOMA)系统和PNOMA系统,本文提出了一种全双工协作部分NOMA(FDCPNOMA)方案以优化UE之间干扰,提高系统可达速率.考虑由一个基站和若干个远近UE构成的FD-CPNOMA系统,针对实际中存在非理想连续干扰消除问题,本文给出了UE配对、非正交率控制及功率分配的优化算法,并推导了此模型下UE中断概率闭式解.仿真结果表明,本文提出的UE配对方案性能优于其他三种配对方案,所提出的PNOMA系统最大可达速率均优于相应的传统NOMA系统,提出的FD-CPNOMA系统在低信噪比下的最大可达速率比半双工协作部分NOMA(HD-CPNOMA)系统和PNOMA系统分别高出95.42%、44.06%,并且在高信噪比下可以较好地实现UE间公平性和平均可达速率的折衷. 展开更多
关键词 FD-CPNOMA 非理想连续干扰消除 UE配对 功率分配 中断概率 平均可达速率
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纱线异纤与针织布面异纤数量的相关性研究
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作者 王前文 陈丽娟 +1 位作者 李秋红 黄仲丽 《棉纺织技术》 CAS 2024年第8期64-68,共5页
为了预测布面异纤的数量,采用有异纤检测功能的USTER CLASSIMAT 5型纱疵仪检测纱线异纤数量,并根据异纤的外观(长度,反射率)对异纤进行分类分级,探讨了纱疵仪检测的纱线异纤数据与对应针织布面上人工检验到的异纤数量之间的相关性。试... 为了预测布面异纤的数量,采用有异纤检测功能的USTER CLASSIMAT 5型纱疵仪检测纱线异纤数量,并根据异纤的外观(长度,反射率)对异纤进行分类分级,探讨了纱疵仪检测的纱线异纤数据与对应针织布面上人工检验到的异纤数量之间的相关性。试验表明:纱疵仪检测的纱线异纤数据与对应针织布面上人工检验到的异纤数量之间表现出强相关。认为:纱线的异纤数量可作为针织工厂采购纱线时的验收基准,结合布面的异纤要求有利于合理使用纱线。 展开更多
关键词 纱疵仪 异纤 漂白布 异纤分级 针织
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改进深度神经网络在爱恩斯坦棋中的应用研究
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作者 蔡彪 徐昕怡 +1 位作者 谢婷 胡洋成 《重庆理工大学学报(自然科学)》 CAS 北大核心 2024年第5期108-114,共7页
爱恩斯坦棋作为一种附带随机性的完美信息博弈,其难度在于每次投掷骰子导致的结果不确定性,这增加了策略设计和局面的评估难度。针对爱恩斯坦棋的游戏规则,提出了一种改进的深度学习方法。对Alpha(go)Zero神经网络模型进行改进和设计,... 爱恩斯坦棋作为一种附带随机性的完美信息博弈,其难度在于每次投掷骰子导致的结果不确定性,这增加了策略设计和局面的评估难度。针对爱恩斯坦棋的游戏规则,提出了一种改进的深度学习方法。对Alpha(go)Zero神经网络模型进行改进和设计,使其能精确地评估各种棋盘状态,生成有效的游戏策略。通过结合改进的残差神经网络和蒙特卡洛树搜索,提取棋局特征并进行局面评估,动态生成策略和进行决策。结合强化学习,以期望胜率为准则,通过自我对弈不断优化权重,改进策略生成效果。实验结果表明:改进的深度学习方法优于全国计算机博弈大赛冠军组算法,进一步验证了深度学习方法在爱恩斯坦棋随机性完美信息博弈中的有效性和可行性。 展开更多
关键词 计算机博弈 非完美信息博弈 爱恩斯坦棋 深度神经网络
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从叙事学角度探析《不完美的她》改编得失
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作者 刘芸 《广东水利电力职业技术学院学报》 2024年第3期101-104,共4页
根据日本电视剧《母亲》翻拍的中国网络剧《不完美的她》,在原剧基础上增加了叙事线索和人物形象,除体现母爱这一主题外,还以女性视角展现其自我意识的觉醒。但该剧在播出后并未收获与原剧相当的评价,甚至颇有非议。基于此,从叙事学角... 根据日本电视剧《母亲》翻拍的中国网络剧《不完美的她》,在原剧基础上增加了叙事线索和人物形象,除体现母爱这一主题外,还以女性视角展现其自我意识的觉醒。但该剧在播出后并未收获与原剧相当的评价,甚至颇有非议。基于此,从叙事学角度出发,探讨、分析《不完美的她》在核心主题、叙事结构、人物形象上改编的优势与不足。 展开更多
关键词 《不完美的她》 《母亲》 翻拍剧 改编
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除尘器箱体立柱稳定性增强方法研究
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作者 王登峰 徐雯凌 +1 位作者 潘立程 郭大鹏 《应用力学学报》 CAS CSCD 北大核心 2024年第1期188-199,共12页
除尘器箱体立柱主要的破坏方式是丧失稳定性。为提高其承载能力,优化除尘装备结构设计,研究箱体立柱稳定性增强构造方法。采用非线性有限元方法,针对除尘器箱体加劲钢墙板—H型钢立柱结构体系,考虑初始缺陷影响,研究箱体立柱失稳机理。... 除尘器箱体立柱主要的破坏方式是丧失稳定性。为提高其承载能力,优化除尘装备结构设计,研究箱体立柱稳定性增强构造方法。采用非线性有限元方法,针对除尘器箱体加劲钢墙板—H型钢立柱结构体系,考虑初始缺陷影响,研究箱体立柱失稳机理。受墙板蒙皮作用,立柱呈现为前翼缘与腹板组成前半部分截面整体弯扭与腹板局部鼓曲相伴发生的相关失稳,且失稳发生在邻近柱顶的高压应力区域。针对失稳特征提出立柱稳定性增强构造措施,即在顶部区域立柱前翼缘两侧加焊加固钢板,加固钢板上、下边界与L形横隔板焊接连接。考察了加固钢板宽度、厚度,L形横隔板厚度以及加固钢板布置范围等因素对于立柱稳定承载力的影响,在此基础上提出了立柱稳定性增强构造的合理设计方法。采取该稳定性增强构造措施后,立柱稳定承载力得以明显提高。 展开更多
关键词 除尘器 箱体立柱 稳定性增强构造 有限元 初始缺陷 蒙皮支撑作用
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日汉对译辞书《杂字类编》中的词语误认现象及成因
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作者 丁喜霞 《辞书研究》 2024年第2期72-81,I0002,共11页
《杂字类编》收录的汉语词以近代汉语口语词和俗语词为主,杂以部分文言词和方言词,也存在一些非“纯汉语”成分和词语误认现象。《杂字类编》中的词语误认现象主要有两种类型:误认非词形式为词、误认词语对应关系。导致词语误认的常见... 《杂字类编》收录的汉语词以近代汉语口语词和俗语词为主,杂以部分文言词和方言词,也存在一些非“纯汉语”成分和词语误认现象。《杂字类编》中的词语误认现象主要有两种类型:误认非词形式为词、误认词语对应关系。导致词语误认的常见因素有:文献来源与文本用字的影响、常用词和常用义的干扰、句法结构的重新分析,各种因素的“影响因子”存在差异,根本原因是对目标语言及其载体的“不完善学习”。结合相关文献,考察日汉对译辞书的词汇及词语误认现象,有助于梳理中日语言文化接触与相互影响的发展脉络,也有助于正确认识双语辞书的语言成分及其语料价值。 展开更多
关键词 对译辞书 词语误认 文献来源 重新分析 不完善学习
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非理想干扰消除全双工协作NOMA系统性能分析及功率分配
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作者 申滨 蒋慧林 董坤明 《电子学报》 EI CAS CSCD 北大核心 2024年第3期792-802,共11页
随着非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术的不断发展,协作NOMA(Cooperative Non-Orthogonal Multiple Access,CNOMA)也受到广泛关注.该文研究了由一个基站(Base Station,BS)、一个远端用户和一个近端用户组成的全... 随着非正交多址接入(Non-Orthogonal Multiple Access,NOMA)技术的不断发展,协作NOMA(Cooperative Non-Orthogonal Multiple Access,CNOMA)也受到广泛关注.该文研究了由一个基站(Base Station,BS)、一个远端用户和一个近端用户组成的全双工(Full-Duplex,FD)协作NOMA(FD-CNOMA)系统,其中近端用户作为一个FD解码转发中继以传输远端用户的信号.考虑实际情况中存在基站与远端用户有无直接链路两种情况,以及非理想连续干扰消除(Successive Interference Cancellation,SIC)对系统带来的残留干扰问题,该文提出并解决了在该模型下用户的功率分配问题.最后,该文基于此模型给出了中继用户和远端用户的中断概率闭式表达式和遍历速率的近似闭式表达式.理论分析与仿真结果表明,即便存在非理想SIC和自干扰,相对于半双工(Half-Duplex,HD)协作NOMA(HDCNOMA)和NOMA系统而言,FD-CNOMA系统表现出更好的系统性能.同时,非理想SIC和中继用户自干扰都会对用户性能产生负面影响,且非理想SIC在遍历速率上对HD机制的影响较FD机制更为严重.最后,文中提出的功率分配方法较随机功率分配和固定功率分配分别获得了13%和10%的速率提升. 展开更多
关键词 协作非正交多址接入 中断概率 平均可实现速率 非理想干扰消除
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非理想检测下多雷达网络节点选择与辐射资源联合优化分配算法 被引量:2
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作者 时晨光 唐志诚 +2 位作者 周建江 严俊坤 王子微 《雷达学报(中英文)》 EI CSCD 北大核心 2024年第3期565-583,共19页
该文针对分布式相控阵多雷达网络的多目标跟踪场景,研究非理想检测条件下的节点选择与辐射资源联合优化分配算法。首先,根据分布式相控阵多雷达网络构成、目标运动模型、雷达量测模型以及雷达节点检测情况,推导非理想检测下以雷达节点... 该文针对分布式相控阵多雷达网络的多目标跟踪场景,研究非理想检测条件下的节点选择与辐射资源联合优化分配算法。首先,根据分布式相控阵多雷达网络构成、目标运动模型、雷达量测模型以及雷达节点检测情况,推导非理想检测下以雷达节点选择、辐射功率和信号带宽为变量的贝叶斯克拉默-拉奥下界(BCRLB)闭式解析表达式,并以此作为多目标跟踪精度衡量指标。在此基础上,以最小化系统各雷达节点对所有目标的总辐射功率为优化目标,以满足目标跟踪精度门限以及给定的系统射频辐射资源限制为约束条件,建立非理想检测条件下多雷达网络节点选择与辐射资源联合优化分配模型,对各时刻雷达节点选择、辐射功率和信号带宽等参数进行联合优化设计,以提升多雷达网络的射频隐身性能。最后,针对上述非线性、非凸优化问题,采用基于障碍函数法和循环最小化算法的4步分解算法进行求解。仿真结果表明,与现有算法相比,所提算法能在满足给定多目标跟踪精度的条件下有效降低分布式相控阵多雷达网络的总辐射功率,至少降低了约32.3%,从而提升其射频隐身性能。 展开更多
关键词 雷达资源分配 分布式多雷达网络 多目标跟踪 非理想检测 贝叶斯克拉默-拉奥下界
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Cascaded ELM-Based Joint Frame Synchronization and Channel Estimation over Rician Fading Channel with Hardware Imperfections 被引量:1
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作者 Qing Chaojin Rao Chuangui +2 位作者 Yang Na Tang Shuhai Wang Jiafan 《China Communications》 SCIE CSCD 2024年第6期87-102,共16页
Due to the interdependency of frame synchronization(FS)and channel estimation(CE),joint FS and CE(JFSCE)schemes are proposed to enhance their functionalities and therefore boost the overall performance of wireless com... Due to the interdependency of frame synchronization(FS)and channel estimation(CE),joint FS and CE(JFSCE)schemes are proposed to enhance their functionalities and therefore boost the overall performance of wireless communication systems.Although traditional JFSCE schemes alleviate the influence between FS and CE,they show deficiencies in dealing with hardware imperfection(HI)and deterministic line-of-sight(LOS)path.To tackle this challenge,we proposed a cascaded ELM-based JFSCE to alleviate the influence of HI in the scenario of the Rician fading channel.Specifically,the conventional JFSCE method is first employed to extract the initial features,and thus forms the non-Neural Network(NN)solutions for FS and CE,respectively.Then,the ELMbased networks,named FS-NET and CE-NET,are cascaded to capture the NN solutions of FS and CE.Simulation and analysis results show that,compared with the conventional JFSCE methods,the proposed cascaded ELM-based JFSCE significantly reduces the error probability of FS and the normalized mean square error(NMSE)of CE,even against the impacts of parameter variations. 展开更多
关键词 channel estimation extreme learning machine frame synchronization hardware imperfection nonlinear distortion synchronization metric
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