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反应等离子烧结制备(Ti,Zr,Nb,Ta,Mo)b_(2)-(Ti,Zr,Nb,Ta,Mo)C基复相高熵超高温陶瓷

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航空制造技术 2025年第3期68卷 117-124页

作者：刘洋钟智浩郭伟明林华泰广东工业大学广州510006

为了进一步改善高熵碳化物和高熵硼化物陶瓷的力学性能,在高熵碳化物(Ti,Zr,Nb,Ta,Mo)C中引入Sib6作为硼源和硅源,通过反应等离子烧结在2000℃下制备了(Ti,Zr,Nb,Ta,Mo)b_(2)-(Ti,Zr,Nb,Ta,Mo)C基复相陶瓷。研究发现,在高温下Sib6与(Ti,... 详细信息

为了进一步改善高熵碳化物和高熵硼化物陶瓷的力学性能,在高熵碳化物(Ti,Zr,Nb,Ta,Mo)C中引入Sib6作为硼源和硅源,通过反应等离子烧结在2000℃下制备了(Ti,Zr,Nb,Ta,Mo)b_(2)-(Ti,Zr,Nb,Ta,Mo)C基复相陶瓷。研究发现,在高温下Sib6与(Ti,Zr,Nb,Ta,Mo)C发生化学反应,生成了高熵硼化物(Ti,Zr,Nb,Ta,Mo)b_(2)、SiC和C。添加Sib6制备的(Ti,Zr,Nb,Ta,Mo)b_(2)-(Ti,Zr,Nb,Ta,Mo)C基复相陶瓷的致密度可达98.7%~99.7%。添加体积分数10%~15%Sib6制备的复相陶瓷中高熵晶粒的尺寸为0.84~0.92μm,显著小于纯(Ti,Zr,Nb,Ta,Mo)C陶瓷的晶粒尺寸(约3.19μm)。由于细晶强化作用,(Ti,Zr,Nb,Ta,Mo)b_(2)-(Ti,Zr,Nb,Ta,Mo)C基复相陶瓷的硬度(23.54~24.93 GPa)高于纯(Ti,Zr,Nb,Ta,Mo)C陶瓷(约23.22 GPa)。同时,(Ti,Zr,Nb,Ta,Mo)b_(2)-(Ti,Zr,Nb,Ta,Mo)C基复相陶瓷的断裂韧性随Sib_(6)添加量的增加而提高,最高可达5.07 MPa·m^(1/2),显著高于纯(Ti,Zr,Nb,Ta,Mo)C陶瓷(约3.02 MPa·m^(1/2))。以(Ti,Zr,Nb,Ta,Mo)C和Sib6为原料,通过反应等离子烧结,可以制备具有较细晶粒结构和优异力学性能的(Ti,Zr,Nb,Ta,Mo)b_(2)-(Ti,Zr,Nb,Ta,Mo)C基复相高熵超高温陶瓷。

关键词：高熵碳化物高熵硼化物反应烧结显微结构力学性能

Analysis of gravity wave activity during stratospheric sudden warmings in the northern hemisphere

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Earth and Planetary Physics 2024年第2期8卷 415-422页

作者： XuanYun Zeng Guang zhong School of Physics and Electronic Sciences Changsha University of Science and TechnologyChangsha 410000China Key Laboratory of Geospace Environment Chinese Academy of SciencesUniversity of Science&Technology of ChinaHefei 230026China

Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The variation characteristics of GWs during SSWs have always been an important *** temperature data from January to March in 2014−2016,provided by the Constellation Observing System for Meteorology,Ionosphere and Climate(COSMIC)mission,we have analyzed global GW activity at 15−40 km in the Northern Hemisphere during SSW *** the SSWs that we studied,the stratospheric temperature rose in one or two longitudinal regions in the Northern Hemisphere;the areas affected extended to the east of 90°*** these SSWs,the potential energy density(E_(p)of GWs expanded and covered a larger range of longitude and altitude,exhibiting an eastward and downward *** E_(p)usually increased,while partially filtered by the eastward zonal *** zonal winds weakened or turned westward,E_(p)began to *** SSWs,the E_(p)usually *** observations can serve as a reference for analyzing the interaction mechanism between SSWs and GWs in future work.

关键词： stratospheric sudden warming gravity wave wind filter

Quantitative analysis on the phase margin of ADRC

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Control Theory and Technology 2023年第1期21卷 4-15页

作者： Sheng zhong Yi Huang beijing Aerospace Automatic Control Institute Beijing100854China Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing100049China

The paper analyzes and compares the phase margins of four active disturbance rejection control(ADRC)designs,which are based on different common-used extended state observers(ESOs)of various orders,for second-order *** quantitative results indicate that,besides good dynamic response,ADRC can guarantee enough phase *** is also proved that by decreasing the order of ESO,the phase margin can be ***,it is demonstrated that the phase margins of the ADRC-based systems can be almost uninfluenced by the uncertainties of the system ***,the theoretical results are verified by both simulations and experiments on a motion control platform.

关键词： Uncertain system Active disturbance rejection control(ADRC) Extended state observer(ESO) Phase margin Crossover frequency

On Geometric Realization of the General Manakov System

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Chinese Annals of Mathematics,Series b 2023年第5期44卷 753-764页

作者： Qing DING Shiping zhong Department of Mathematics Wenzhou UniversityWenzhou 325035ZhejiangChina School of Mathematical Sciences Fudan UniversityShanghai 200433China School of Mathematics and Computer Sciences Gannan Normal UniversityGanzhou 341000JiangxiChina

It is well-known that the general Manakov system is a 2-components nonlinear Schrodinger equation with 4 nonzero real *** analytic property of the general Manakov system has been well-understood though it looks *** paper devotes to exploring geometric properties of this system via the prescribed curvature representation in the category of Yang-Mills’*** models of moving curves evolving in the symmetric Lie algebras u(2,1)=k_(α)⊕m_(α)(α=1,2)and u(3)=k_(3)⊕m_(3)are shown to be simultaneously the geometric realization of the general Manakov *** reflects a new phenomenon in geometric realization of a partial differential equation/system.

关键词： Manakov system Geometric realization Prescribed curvature representation

富水砂土隧道注浆加固效果评价研究:以郑州地铁7号线砂土隧道为例

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西北地质 2025年第1期58卷 315-322页

作者：钟宏伟秦鹏飞卢再光张颖郑州铁路职业技术学院铁道工程学院河南郑州450010 黄河科技学院工学部河南郑州451000 重庆交通大学水利水运工程教育部重点实验室重庆400074

在地质环境日趋复杂和恶劣的工程背景下,注浆加固的质量要求越来越高,建立科学合理的注浆效果评价体系,具有重要的理论意义和研究价值。针对注浆量核算法、检查孔分析法、P-Q-t曲线法及地球物理探测法等工程中应用较广泛的注浆效果检测... 详细信息

在地质环境日趋复杂和恶劣的工程背景下,注浆加固的质量要求越来越高,建立科学合理的注浆效果评价体系,具有重要的理论意义和研究价值。针对注浆量核算法、检查孔分析法、P-Q-t曲线法及地球物理探测法等工程中应用较广泛的注浆效果检测方法,通过抽取一、二级影响因素确立层次评价体系,并结合专家意见与实际工况构建了注浆效果评价数学模型。然后基于模糊数学的基本原理,将权向量作为评价因素的权重进行量化,通过矩阵运算实现了模糊现象的数学表达,完成了砂土隧道注浆效果的准确评价。最后结合郑州地铁7号线砂土隧道,通过模糊评价综合分析,认为注浆效果等级达到良好等级(b)。隧道实际开挖期间,未出现任何形式的水文、地质干扰,表明评价方法科学高效,可为其他工程施工提供指导或参考。

关键词：隧道注浆检查孔分析地球物理探测模糊理论效果评价

EVALUATION OF THREE-DIMENSIONAL NUMERICAL MODEL FOR SALINE INTRUSION AND PURGING IN SEWAGE OUTFALLS

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Journal of Hydrodynamics 2007年第1期19卷 48-53页

作者： WU Wei YAN zhong-min College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China

Saline intrusion into sewage outfalls will greatly decrease the efficiency of the structures. The numerical model for this flow has been limited to one- and two-dimensional ones. In this article, a three-dimensional numerical model for saline intrusion and purging in sewage outfalls was developed. The flow was modeled in three dimensions under turbulent conditions with the RNG k-ε turbulence model. The numerical results provided quantitative evidence of the fundamental flow mechanisms that took place during saline intrusion and purging. The comparisons of the results with that of two-dimensional model and that of experiments indicate that the three-dimensional numerical model developed in this article is more effective in predicting the internal flow in outfalls.

关键词： saline intrusion sea ouffalls numericalsimulation three-dimensional numerical model

A fully nonlinear and weakly dispersive water wave model for simulating the propagation,interaction,and transformation of solitary waves

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Journal of Hydrodynamics 2019年第6期31卷 1099-1114页

作者： Zhengyong zhong Keh-Han Wang INTECSEA Inc. HoustonTXUSA Department of Civil and Environmental Engineering University of HoustonHoustonTXUSA

This paper presents the development of a theoretical model of fully nonlinear and weakly dispersive(FNWD)waves and numerical techniques for simulating the propagation,interaction,and transformation of solitary *** the standard expansion method and without the limit of small nonlinear parameter defined as the ratio of the wave height versus water depth,a set of model equations describing the FNWD waves in a domain of moderately varying bottom topography are *** solitary wave solutions satisfying the FNWD equations are also ***,a time-accurate and stabilized finite-element code to solve the governing equations is developed for wave *** solitary wave solutions of FNWD,weakly nonlinear and weakly dispersive(WNWD),and Laplace equations based models in terms of wave profile and phase speed are compared to examine their related features and *** on the overtaking collision of two unidirectional solitary waves of different amplitudes,i.e.,ax and a2 where a1>a2,are carried out using both the FNWD and WNWD water wave *** cases by running the FNWD and WNWD models are performed to identify the critical values of a1/a2 for forming a flattened merging wave peak,which is the condition used to determine if the stronger wave is to pass through the weaker one or both waves are to remain separated during the encountering *** is interesting to note the critical values of a1/a2 obtained from the FNWD and WNWD models are found to be different and greater than the value of 3 proposed by Wu through the theoretical analysis of the Korteweg-de Vries(KdV)***,the phenomena of wave splitting and nonlinear focusing of a solitary wave propagating over a three-dimensional semicircular shoal are *** results obtained from both the FNWD and WNWD models showing the fission process of separating a main solitary wave into multiple waves of decreasing amplitudes are presented,compared,and dis

关键词： Fully nonlinear and weakly dispersive waves overtaking collision boussinesq models solitary waves finite-element method wave shoaling

Data-driven cooperative output regulation of multi-agent systems under distributed denial of service attacks

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Science China(Information Sciences) 2023年第9期66卷 5-20页

作者： Weinan GAO zhong-Ping JIANG State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Department of Electrical and Computer Engineering Tandon School of Engineering New York University

This paper addresses an optimal, cooperative output regulation problem for multi-agent systems with distributed denial of service attacks and unknown system dynamics. Unlike existing studies, the proposed solution is essentially a learning-based control strategy such that one can obtain a distributed control policy with internal models through online data and analyze the resilience of closed-loop systems, both without the precise knowledge of system dynamics in the state-space model. The efficiency of the proposed methodology is validated using computer simulations.

关键词： cooperative output regulation adaptive dynamic programming learning-based control multi-agent systems cybersecurity

宏基因组二代测序技术对儿童血液病继发血流感染的诊断效能的观察性研究

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中国实验血液学杂志 2025年第1期33卷 280-285页

作者：郑俊生叶中绿刘丽丽广东医科大学附属医院儿童血液肿瘤中心广东湛江524000

目的:探讨宏基因组二代测序技术(m NGS)在血液病继发血流感染患儿病原体检测中的临床应用价值。方法:2021年11月至2023年5月广东医科大学附属医院儿童血液肿瘤中心收治的42例血液病继发血流感染患儿纳入研究,回顾性分析其临床资料、外周... 详细信息

目的:探讨宏基因组二代测序技术(m NGS)在血液病继发血流感染患儿病原体检测中的临床应用价值。方法:2021年11月至2023年5月广东医科大学附属医院儿童血液肿瘤中心收治的42例血液病继发血流感染患儿纳入研究,回顾性分析其临床资料、外周血m NGS和传统血培养结果,以及病原体分布特征和m NGS的诊断效能。结果:纳入的42例患儿中,按照疾病类型划分,包括再生障碍性贫血2例(4.8%)、急性淋巴细胞白血病27例(64.3%)、急性髓系白血病7例(16.7%)、慢性髓系白血病1例(2.4%)、嗜血细胞性淋巴组织细胞增生症2例(4.8%)、非霍奇金淋巴瘤2例(4.8%)和湿疹-血小板减少-免疫缺陷综合征1例(2.4%)。共31例外周血标本m NGS检测出病原体,阳性率为73.8%(31/42),明显高于传统血培养阳性率16.7%(7/42),二者差异具有统计学意义(P<0.05)。m NGS检测出的病原体阳性病例中,细菌阳性23例(74.2%),病毒阳性12例(38.7%),真菌阳性9例(29.0%);外周血m NGS阳性样本中有32.2%(10/31)为混合病原体,而传统血培养不能有效地检测到此类情况。结论:外周血m NGS在血液病继发血流感染病原体检测中具有优越性,阳性率高于传统血培养,能够检出病毒、罕见病原体、混合病原体,具有良好的临床应用价值。

关键词：血液病血流感染病原体儿童