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Seismic response of pile-supported structures considering the coupling of inertial and kinematic interactions in different soil sites

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FRONTIERS OF STRUCTURAL AND CIVIL ENGINEERING 2024年第9期18卷 1350-1361页

作者： Zhao, Huiling Zhang, fan Shanghai Univ Dept Civil Engn Shanghai 200444 Peoples R China

Dynamic soil-pile-superstructure interaction is crucial for understanding pile behavior in earthquake-prone ground. Evaluating the safety of piles requires determining the seismic bending moment caused by combined inertial and kinematic interactions, which is challenging. This paper addresses this problem through numerical simulations of piles in different soil sites, considering soil nonlinearity. Results reveal that the period of the soil site significantly affects the interaction among soil, piles, and structures. Bending moments in soft and hard soil sites exceed those in medium soil sites by more than twice. Deformation modes of piles exhibit distinct characteristics between hard and soft soil sites. Soft soil sites exhibit a singular inflection point, while hard soil sites show two inflection points. In soft soil sites, pile-soil kinematic interaction gradually increases bending moment from tip to head, with minor influence from superstructure's inertial interaction. In hard soil sites, significant inertial effects from soil, even surpassing pile-soil kinematic effects near the tip, lead to reversed superposition bending moment. Superstructure's inertial interaction notably impacts pile head in hard soil sites. A simplified coupling method is proposed using correlation coefficient to represent inertial and kinematic interactions. These findings provide insights into complex seismic interactions among soil, piles, and structures.

关键词： pile seismic response soft soil inertial interaction kinematic interaction PSEUDOSTATIC APPROACH STRUCTURE SYSTEMS CYCLIC MOBILITY BEHAVIOR MODEL

Impact of non-ideal UE hardware on cell-free massive MIMO network with centralized operation

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Science China(Information Sciences) 2024年第4期67卷 255-271页

作者： Ning LI Pingzhi fan Institute of Mobile Communications Southwest Jiaotong University

This paper investigates the impact of non-ideal user equipment(UE) hardware on a cell-free(CF) massive MIMO(mMIMO) network with centralized operation under spatially correlated channels. The minimum mean-squared error(MMSE) estimator can be derived with the help of the generic non-ideal UE hardware model. It is demonstrated that even if the effective signal-to-noise ratio approaches infinity, pilot contamination and imperfect hardware can cause a non-zero estimation error floor. After that, a lower bound is determined for the ergodic uplink capacity of the centralized CF mMIMO network under non-ideal UE hardware. Moreover, the optimal receive combining vector is obtained to maximize the uplink spectral efficiency(SE). The maximum ratio(MR) and regularized zero-forcing(RZF) combining schemes are offered as alternatives in light of the computational complexity of the MMSE receiver. Comparing the RZF to the MMSE scheme under different levels of hardware impairments, our findings indicate that the RZF receiver suffers a negligible loss in total SE. For MR combining, a novel closed-form uplink achievable SE expression is obtained based on the MMSE estimator and the use-and-then-forget bounding technique. This expression gives vital insights into the achievable uplink performance with UE hardware impairments. Besides, for various hardware impairment factors, the impact of pilot sequence length on average sum SE is disclosed for different receive combining schemes. To increase the overall SE of the max-min fairness scheme, a heuristic fractional power control scheme with UE hardware impairments is developed, which can essentially avoid sacrificing the SE of other UEs while maximizing the SE of the unluckiest UE in the whole network. Finally,our theoretical performance analysis and power control algorithm are validated by simulation results, and fundamental design guidelines are provided for selecting hardware satisfying the practical UE requirements.

关键词： cell-free massive MIMO centralized operation spatially correlated channels hardware impairments channel estimation uplink spectral efficiency optimal receive combining pilot length design fractional power control

Set-Membership Filtering Approach to Dynamic Event-Triggered Fault Estimation for a Class of Nonlinear Time-Varying Complex Networks

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 638-648页

作者： Xiaoting du Lei Zou Maiying Zhong the College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China IEEE the College of Information Science and Technology Donghua UniversityShanghai 201620 the Engineering Research Center of Digitalized Textile and Fashion Technology Ministry of EducationShanghai 201620China

The present study addresses the problem of fault estimation for a specific class of nonlinear time-varying complex networks,utilizing an unknown-input-observer approach within the framework of dynamic event-triggered mechanism(DETM).In order to optimize communication resource utilization,the DETM is employed to determine whether the current measurement data should be transmitted to the estimator or *** guarantee a satisfactory estimation performance for the fault signal,an unknown-input-observer-based estimator is constructed to decouple the estimation error dynamics from the influence of fault *** aim of this paper is to find the suitable estimator parameters under the effects of DETM such that both the state estimates and fault estimates are confined within two sets of closed ellipsoid *** techniques of recursive matrix inequality are applied to derive sufficient conditions for the existence of the desired estimator,ensuring that the specified performance requirements are met under certain ***,the estimator gains are derived by minimizing the ellipsoid domain in the sense of trace and a recursive estimator parameter design algorithm is then ***,a numerical example is conducted to demonstrate the effectiveness of the designed estimator.

关键词： Dynamic event-triggered mechanism(DETM) fault estimation nonlinear time-varying complex networks set-member-ship filtering unknown input observer

Recent advances in small-scale hydrogel-based robots for adaptive biomedical applications

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Nano Research 2024年第2期17卷 649-662页

作者： Mingzhe Nie Qilong Zhao Xuemin du Institute of Biomedical&Health Engineering Shenzhen Institute of Advanced Technology(SIAT)Chinese Academy of Sciences(CAS)Shenzhen 518055China

Small-scale robots,ranging in size from micrometers to centimeters,have gained significant attention in the biomedical ***,conventional small-scale robots made of rigid materials encounter challenges in adapting themselves to the soft tissues and complicated environments of human *** to the rigid counterpart,small-scale hydrogel-based robots hold great promises due to their tissue-like low modulus,outstanding biocompatibility and accessible stimuli-responsive *** attributes offer small-scale hydrogel-based robots with multimodal locomotion and reinforced functions,further enhancing the adaptability in manipulation and tasks execution for various biomedical *** this review,we present recent advances in small-scale hydrogel-based *** first summarize the design principles of small-scale hydrogel-based robots including materials,fabrication techniques and manipulation strategies,then highlighting their upgraded functions and adaptive biomedical ***,we discuss existing challenges and future perspectives for small-scale hydrogel-based robots.

关键词： small-scale robot hydrogel locomotion multi-function adaptability

Concise extraction and characterization of the pore-throat network in unconventional hydrocarbon reservoirs: A new perspective

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Petroleum Science 2024年第3期21卷 1474-1487页

作者： Shu-Heng du Yong-Min Shi State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Engineering Science University of Chinese Academy of SciencesBeijing100049China School of Earth and Space Sciences Peking UniversityBeijing100871China

In this study,a new image-based method for the extraction and characterization of pore-throat network for unconventional hydrocarbon storage and exploitation is proposed.“Pore-throat solidity”,which is analogous to particle solidity,and a new method for automatic identification of pores and throats in tight sandstone oil reservoirs are ***,the“pore-throat combination”and“pure pore”are defined and distinguished by drawing the cumulative probability curve of the pore-throat solidity and by selecting an appropriate cutoff *** the discrete grid set is recognized as a pore-throat combination,Legendre ellipse fitting and minimum Feret diameter are *** the pore and throat grid sets are identified as pure pores,the pore diameter can be directly *** the new method,the analytical results for the physical parameters and pore radius agree well with most prior *** results comparing the maximum ball and the new model could also prove the accuracy of the latter's in micro and nano *** new model provides a more practical theoretical basis and a new calculation method for the rapid and accurate evaluation of the complex processes of oil migration.

关键词： Hydrocarbon exploitation Pore Throat Porous media Identification

Combination of diketone and PAO to achieve macroscale oil-based superlubricity at relative high contact pressures

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Friction 2024年第5期12卷 869-883页

作者： Shaonan du Chenhui ZHANG Zhi LUO State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing100084China Beijing National Laboratory of Molecular Sciences CAS Key Laboratory of Engineering PlasticsInstitute of ChemistryChinese Academy of SciencesBeijing100190China

1-(4-ethylphenyl)-nonane-1,3-dione(0206)is an oil-soluble liquid molecule with rod-like *** this study,the chelate(0206-Fe)with octahedral structure was prepared by the reaction of ferric chloride and 1,*** experimental results show that when using 0206 and a mixed solution containing 60%0206-Fe and 40%0206(0206-Fe(60%))as lubricants of the steel friction pairs,superlubricity can be achieved(0.007,0.006).But their wear scar diameters(WSD)were very large(532µm,370µm),which resulted in the pressure of only 44.3 and 61.8 MPa in the contact areas of the friction *** 0206-Fe(60%)was mixed with PAO6,it was found that the friction coefficient(COF)decreased with increase of 0206-Fe(60%)in the *** the ratio of 0206-Fe(60%)to PAO6 was 8:2(PAO6(20%)),it exhibited better comprehensive tribological properties(232.3 MPa).Subsequent studies have shown that reducing the viscosity of the base oil in the mixed solution helped to reduce COF and increased *** the COF,contact pressure,and running-in time,it was found that the mixed lubricant(Oil3(20%))prepared by the base oil with a viscosity of 19.7 mPa·s(Oil3)and 0206-Fe(60%)exhibited the best tribological properties(0.007,161.4 MPa,3,100 s).

关键词： diketone oil-based lubricants chelate superlubricity

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有向动态网络中基于模体演化的链路预测方法

计算机应用研究 2019年第5期36卷 1441-1445,1453页

作者：杜凡刘群重庆邮电大学计算智能重庆市重点实验室

以往传统的链路预测方法大多数针对无向网络,而实际上大多数社交网络是有向的,并且没有考虑网络中同一节点对之间的重复边以及微观演化信息,因此不能较好地解决有向动态网络中的链路预测问题。针对有向网络,将节点对之间的重复边信息转... 详细信息

以往传统的链路预测方法大多数针对无向网络,而实际上大多数社交网络是有向的,并且没有考虑网络中同一节点对之间的重复边以及微观演化信息,因此不能较好地解决有向动态网络中的链路预测问题。针对有向网络,将节点对之间的重复边信息转换为该节点对之间连边的权值;接着采用了基于三元组模体的演化模型,对滑动窗口中相邻时间片的模体转换概率进行统计后,采用指数加权滑动平均法对其进行时序分析得到不同模体转换概率的预测矩阵,进而使用该矩阵对网络中的链边进行预测。这不仅充分利用了网络微观演化信息,而且解决了动态网络中重复边的问题。最后对实验结果进行分析发现,在高全局聚类系数高平均度的网络中AUC相比Triad Transition Matrix方法提高了近0.01,而相比CN方法提高更多。因此,所提方法能够较好地应用网络微观演化信息进行链路预测。

关键词：时序链路预测有向网络模体演化时序分析

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我国课程政策执行的样态、困境及优化

教学与管理 2019年第7期 12-15页

作者：杜迎范中原工学院信息商务学院郑州451191

课程政策的执行力直接影响着课程政策的实施成效。在实践中,课程政策时常无法完全实现其目标,这是基于在课程政策中仍然存在着传统意识形态、"工具理性主义"、课程政策体系及其评价机制不完整等问题。为提升课程政策的实践性,应从以下... 详细信息

课程政策的执行力直接影响着课程政策的实施成效。在实践中,课程政策时常无法完全实现其目标,这是基于在课程政策中仍然存在着传统意识形态、"工具理性主义"、课程政策体系及其评价机制不完整等问题。为提升课程政策的实践性,应从以下方面尝试克服问题:关注课程政策的实践意义;加深课程政策的理论性研究;协调课程政策中各方主体关系;完善课程政策的评价机制。

关键词：课程政策执行力课程实践工具理性主义

坝面帷幕灌浆技术在竹银水库主坝坝基处理中的应用

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水利水电科技进展 2011年第6期31卷 55-58页

作者：曾凡杜中国水利水电第八工程局有限公司湖南长沙410007

针对竹银水库主坝坝基地质条件及工期紧张、基坑面临被暴雨淹没的实际情况,对河床坝基采取先进行坝体填筑、后在坝面进行帷幕灌浆基础处理的施工方法,并针对已填筑坝体、坝体与坝基接触段、基岩采取不同的技术措施,确保帷幕灌浆幕体与... 详细信息

针对竹银水库主坝坝基地质条件及工期紧张、基坑面临被暴雨淹没的实际情况,对河床坝基采取先进行坝体填筑、后在坝面进行帷幕灌浆基础处理的施工方法,并针对已填筑坝体、坝体与坝基接触段、基岩采取不同的技术措施,确保帷幕灌浆幕体与填筑坝体结合良好,形成完整的垂直防渗体系。该施工方法既解决了坝体填筑与基础处理的矛盾,又使工程得以安全度汛,使总体工期得到了保证,可供类似工程参考。

关键词：帷幕灌浆防渗坝基处理施工方案竹银水库