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An uncertainty investigation for liner impedance eduction methods

Chinese Journal of Aeronautics 2024年第3期37卷 49-59页

作者： Weihao SHI xiaodong jing School of Energy and Power Engineering Beihang UniversityBeijing 100191China

Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic *** this end,it is important to fully investigate the uncertainty problem,to which only limited attention has been devoted so *** paper considers the possibility of acoustically-induced structural vibration as a nonnegligible uncertainty or error source in impedance eduction *** the frequency moves away from the resonant frequency,with the increase in the value of cavity reactance,the acoustic particle velocity inside liner orifices possibly decreases to the extent comparable to the vibration velocity of liner facing ***,the acoustically-induced vibration,although generally being weak except at the inherent structural frequencies,may considerably affect the impedance eduction results near the anti-resonant frequency where the liner has poor *** demonstrate the effect of structural vibration,the vibration velocity of liner facing sheet is estimated from the experimentally educed admittance of the liner samples whose orifices are sealed with ***,a three-dimensional numerical model is set up,in which normal particle velocity is introduced over the solid portion of liner facing sheet to imitate structural vibration,rather than directly solving the acoustic-structural coupling *** shown by the results,the vibration of liner facing sheet,whose velocity is as small as estimated by the experiment,can result in anomalous deviation of the educed impedance from the impedance model near the anti-resonant *** trend that the anomalous deviation varies with frequency is numerically captured.

关键词： Impedance eduction Uncertainty analysis Acoustically-induced structural vibration Anti-resonant frequency Perforated liner

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真三轴压缩及卸载条件下充填体力学特性研究

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矿业研究与开发 2024年第6期44卷 56-64页

作者：荆晓东宋泽普寇云鹏朱庚杰山东黄金集团有限公司充填工程实验室山东莱州市261441 山东黄金集团有限公司山东济南250100

对于采用充填采矿法的矿山,充填体是井下采场的重要组成部分,在先采矿房并充填完成后再回采矿柱的充填采矿工艺过程中,充填体受原生地应力及矿体开挖的扰动、卸载作用。基于充填开采工艺过程中的应力变化路径,开展充填体真三轴压缩及卸... 详细信息

对于采用充填采矿法的矿山,充填体是井下采场的重要组成部分,在先采矿房并充填完成后再回采矿柱的充填采矿工艺过程中,充填体受原生地应力及矿体开挖的扰动、卸载作用。基于充填开采工艺过程中的应力变化路径,开展充填体真三轴压缩及卸载试验,分析充填体失稳破坏过程及声发射响应特征,研究充填体力学特性。结果表明:真三轴压缩条件下充填体试件的破坏形式主要以拉伸破坏为主,表现出更好的弹性,峰值强度和弹性模量随养护时间的增加和围压的增大而增大;单向卸载条件下,充填体试件峰值强度较真三轴压缩条件下的峰值强度降低约17.74%,峰值强度随围压的增大而增大,弹性模量随围压的增大而减小,泊松比随围压的增大先增大后减小;双向卸载条件下,充填体试件快速失稳破坏,峰值强度较真三轴压缩条件下的峰值强度降低约17.76%,充填体试件的峰值强度、弹性模量、泊松比均随围压的增大而增大;充填体试件在双向卸载条件下比单向卸载条件下产生的变形更大,破坏强度也更低。

关键词：充填体力学特性真三轴压缩单向卸载双向卸载

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耐心资本推动水利基础设施高质量发展的作用机理及政策建议

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中国水利 2024年第14期 67-72页

作者：景晓栋田贵良孙盟河海大学商学院南京211100 河海大学经济与金融学院南京211100 长江保护与绿色发展研究院南京210098 西安建筑科技大学管理学院西安710055

随着全球气候变化和人口增长的挑战,水资源管理和水利基础设施的高质量发展愈发重要。耐心资本是推动水利新质生产力向更高效、更可持续方向发展的重要资本形式,为水利基础设施建设投融资提供了新的渠道和策略。通过分析水利基础设施建... 详细信息

随着全球气候变化和人口增长的挑战,水资源管理和水利基础设施的高质量发展愈发重要。耐心资本是推动水利新质生产力向更高效、更可持续方向发展的重要资本形式,为水利基础设施建设投融资提供了新的渠道和策略。通过分析水利基础设施建设领域投融资机制存在问题,梳理了耐心资本的概念界定及与传统资本的对比分析,系统总结了耐心资本在基础设施投融资中的成功应用,详细分析了耐心资本对推动水利基础设施建设的重要作用及其与水利基础设施投融资特点的吻合性。最后围绕进一步优化政府和社会资本合作(PPP)法律与政策环境、建立健全水利项目财务激励和补贴政策、优化水利基础设施融资模式、推动水利技术创新和推广应用、加强对环境和社会效益的评估和监控等方面提出了相应的政策建议,以期为增强水利基础设施的可持续性并提升长期效益提供参考。

关键词：水利基础设施耐心资本水利新质生产力水资源管理可持续发展

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尾砂粒级组成对胶结充填料流变特性与强度的影响

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黄金科学技术 2024年第4期32卷 631-639页

作者：盛宇航裴佃飞齐兆军荆晓东山东黄金矿业科技有限公司山东济南250000 山东省深海深地金属矿智能开采重点实验室山东济南250000 山东黄金集团有限公司山东济南250000

为探究尾砂粒级组成与充填料流变特性及强度之间的关系,采用全尾砂、旋流器分级溢流和底流尾砂经人工配制成5种尾砂充填料,开展了不同粒级组成尾砂充填料流变与强度试验。结果表明:随着尾砂中-38μm细粒级含量的增加,充填料浆屈服应力... 详细信息

为探究尾砂粒级组成与充填料流变特性及强度之间的关系,采用全尾砂、旋流器分级溢流和底流尾砂经人工配制成5种尾砂充填料,开展了不同粒级组成尾砂充填料流变与强度试验。结果表明:随着尾砂中-38μm细粒级含量的增加,充填料浆屈服应力和塑性黏度增加,且-38μm细粒级含量越高充填料浆屈服应力和塑性黏度增加幅度越大;随着细粒级尾砂含量的增加,水化膜厚度呈先增加后降低的变化趋势;充填料浆初始屈服应力和塑性黏度受水化膜厚度和固体颗粒比表面积的双重影响;当细粒级尾砂含量超过44.37%时,水化膜厚度与充填料浆初始屈服应力和塑性黏度之间存在负指数关系。随着细粒级尾砂含量的增加,尾砂充填体强度先增加后减小,细粒级含量为44.37%时为尾砂最佳粒级组成,此时充填体中尾砂堆积所形成的骨架结构最密实,充填体总孔隙率、平均孔径和大于0.2μm有害孔占比最小。

关键词：尾砂粒级组成胶结充填料流变特性水化膜厚度强度孔结构

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制备高固含量低黏度聚合物多元醇的影响因素研究

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聚氨酯工业 2024年第2期39卷 43-45,50页

作者：荆晓东耿佃勇孙言丛徐培贾飞山东尚正新材料科技股份有限公司山东淄博256405

介绍了制备高固含量低黏度聚合物多元醇(POP)的工艺历程,讨论了大分子单体、链引发剂、链转移剂等对制备POP指标的影响。结果表明,选定用4或6官能度大分子单体作为稳定剂且质量分数为3%、链转移剂异丙醇(IPA)质量分数为10%、新型自由基... 详细信息

介绍了制备高固含量低黏度聚合物多元醇(POP)的工艺历程,讨论了大分子单体、链引发剂、链转移剂等对制备POP指标的影响。结果表明,选定用4或6官能度大分子单体作为稳定剂且质量分数为3%、链转移剂异丙醇(IPA)质量分数为10%、新型自由基引发剂V601质量分数为0.3%时,可以制得高固含量、低黏度、高稳定性的聚合物多元醇。

关键词：聚合物多元醇大分子单体链引发剂链转移剂聚氨酯

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Temperature field simulation of polyolefin-absorber mixture by FDTD-FDM model during microwave heating

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Chinese Journal of Chemical Engineering 2020年第11期28卷 2900-2917页

作者： xiaodong jing Hao Wen Zhihong Xu State Key Laboratory of Multiphase Complex Systems Beijing Engineering Research Centre of Process Pollution ControlInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

This work has performed a numerical simulation of the temperature field during microwave heating of polyolefin-absorber mixture by means of a combined electric and thermal model.A finite difference time domain was used to model the electric field distribution within the cavity,while the finite difference method was used to calculate the temperature field distribution in different *** study has focused only on the process from room temperature to 500 K for reducing heating time and energy *** temperature range is a process with high energy consumption,difficult to control and great influence on the follow-up *** dependence of dielectric properties and thermal properties of heated materials are fully considered and simulated through an iterative *** simulation results show that input power,the size and location of the heated materials,the position of the waveguide,and the kinds of microwave absorbers are important factors affecting the heating *** a result,the uniform temperature distribution(the temperature difference Tdb10 K)can be achieved by choosing the appropriate input power(500–2000 W),the appropriate proportion of microwave absorber(the volume ratio of Si C to HDPE is 30:70),and combining with the moving and rotating of the heated *** uniform temperature field obtained without mechanical stirring is very important for reducing energy consumption and subsequent reactions.

关键词： Microwave heating Temperature field Finite difference time domain Finite difference method

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Multi-domain Spectral Immersed Interface Method for Solving Elliptic Equation with a Global Description of Discontinuous Functions

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Chinese Journal of Aeronautics 2012年第3期25卷 297-310页

作者： JIANG Yongsong LIANG An SUN Xiaofeng jing xiaodong School of Jet Propulsion Beihang University Beijing 100191 China Department of Compressor Design Shenyang Aeroengine Research Institute Shenyang 110015 China AVIC Commercial Aircrafl Engine Co. Ltd. Shanghai 200241 China

This paper presents the extension of the global description approach of a discontinuous function, which is proposed in the previous paper, to a spectral domain decomposition method. This multi-domain spectral immersed interlace method（IIM） divides the whole computation domain into the smooth and discontinuous parts. Fewer points on the smooth domains are used via taking advantage of the high accuracy property of the spectral method, but more points on the discontinuous domains are employed to enhance the resolution of the calculation. Two that the domain decomposition technique can placed around the discontinuity. The present reached, in spite of the enlarged computational discontinuous problems are tested to verify the present method. The results show reduce the error of the spectral IIM, especially when more collocation points are method is t：avorable for the reason that the same level of the accuracy can be domain.

关键词： computational aerodynamics immersed interface method immersed boundary method Chebyshev spectral method domain decomposition method

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公共供水管网工业用水权确权及交易研究

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中国水利 2024年第4期 42-46页

作者：景晓栋田贵良班晴晴王高旭朱红斌崔冬冬河海大学商学院南京211100 河海大学经济与金融学院南京211100 长江保护与绿色发展研究院南京210098 南京水利科学研究院南京210029 浙江省义乌市水务局义乌322000

推行公共供水管网工业用水户用水权交易,对于进一步规范工业企业用水行为、优化水资源配置、提高水资源利用效率具有重要意义。在系统剖析公共供水管网工业用水权交易重要意义的基础上,详细分析了公共供水管网工业用水权的确权思路及交... 详细信息

推行公共供水管网工业用水户用水权交易,对于进一步规范工业企业用水行为、优化水资源配置、提高水资源利用效率具有重要意义。在系统剖析公共供水管网工业用水权交易重要意义的基础上,详细分析了公共供水管网工业用水权的确权思路及交易流程框架,并在此基础上围绕加强公共供水管网工业用水户用水权市场顶层设计、以最严格的水资源管理制度管水用水、加快推进公共供水管网工业用水户用水权市场建设、强化公共供水管网用水权市场保障机制4个方面提出加快完善我国公共供水管网工业用水户用水权交易体系的政策建议。

关键词：公共供水管网用水权交易用水权改革

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A second-order numerical method for elliptic equations with singular sources using local flter

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Chinese Journal of Aeronautics 2013年第6期26卷 1398-1408页

作者： Jiang Yongsong Fang Le jing xiaodong Sun Xiaofeng Francis Leboeuf Department of Compressor Design AVIC Shenyang Engine Design and Research Institute School of Energy and Power Engineering Beihang University Ecole Centrale de Pe'kin Laboratoire International Associe'Beihang University MOE Key Laboratory of High-speed Railway Engineering Southwest Jiaotong University Ecole Centrale de Lyon Laboratoire de Me'canique des Fluides et d’Acoustique Universite' de LyonEcully 69134France

The presence of Dirac delta function in differential equation can lead to a discontinuity,which may degrade the accuracy of related numerical *** improve the accuracy,a secondorder numerical method for elliptic equations with singular sources is introduced by employing a local kernel *** this method,the discontinuous equation is convoluted with the kernel function to obtain a more regular *** the original equation is replaced by this fltered equation around the singular points,to obtain discrete numerical *** unchanged equations at the other points are discretized by using a central difference scheme.1D and 2D examples are carried out to validate the correctness and accuracy of the present *** results show that a second-order of accuracy can be obtained in the fltering framework with an appropriate integration ***,the present method does not need any jump condition,and also has extremely simple form that can be easily extended to high dimensional cases and complex geometry.

关键词： Computational aerodynamics Immersed boundary method Immersed interface method Kernel flter Singular source

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Investigation of straightforward impedance eduction method on single-degree-of-freedom acoustic liners

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Chinese Journal of Aeronautics 2018年第12期31卷 2221-2233页

作者： Xianghai QIU Bo XIN Long WU Yang MENG xiaodong jing Fluid and Acoustic Engineering Laboratory School of Energy and Power Engineering Beihang University

In order to address the current aircraft noise problem, the knowledge of impedance of acoustic liners subjected to high-intensity sound and grazing flow is of crucial importance to the design of high-efficiency acoustic nacelles. To this end, the present study is twofold. Firstly, the StraightForward impedance eduction Method(SFM) is evaluated by the strategy that the impedance of a liner specimen is firstly experimentally educed on a flow duct using the SFM, and then its accuracy is checked by comparing the numerical prediction with the measured wall sound pressure of the flow duct. Secondly, the effects of grazing flow and high-intensity sound on the impedance behavior of two single-layer liners are investigated based on comparisons between educed impedance and predictions by three impedance models. The performance of the SFM is validated by showing that the educed impedance leads to excellent agreement between the simulation and the measured wall sound pressure for different grazing flow Mach numbers and Sound Pressure Levels(SPLs) and over a frequency range from 3000 Hz down to 500 Hz. The grazing flow effect generally has the tendency that the acoustic resistance exhibits a slight decrease before it increases linearly with an increase in Mach,predicted successfully by the sound-vortex interaction theoretical model and the Kooi semi-empirical impedance model. However, the Goodrich semi-empirical impedance model gives only a simple linear relation of acoustic resistance starting from Mach zero. Additionally, when the SPL increases from 110 to 140 d B in the present investigation, the acoustic resistance exhibits a significant increase at all frequencies in the absence of flow; however, the resistance decreases slightly under a grazing flow of Mach 0.117. It indicates that the SPL effect can be greatly inhibited when flow is present,and the grazing flow effect can be reduced partly as well at a relatively high SPL.

关键词： Acoustic liner Experimental validation Grazing flow effect High sound intensity effect Impedance eduction Numerical evaluation Straightforward impedance eduction method

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