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Adaptive command filter constraint control of rolling mill torsional vibration under current harmonic

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Journal of Iron and Steel Research International 2023年第9期30卷 1782-1791页

作者： Shu-zong Chen Cheng jia Chang-chun Hua jia-qiang Chen Institute of Electrical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina

An adaptive command filter control strategy was proposed to realize the asymptotic tracking of the roll speed,which successfully suppressed torsional vibration for the main drive system of the rolling mill with nonlinear friction,nonlinear damping,current harmonic,time-varying stiffness and unknown disturbance.A finite time predetermined performance method was proposed,so that the speed tracking error of the main transmission system was always constrained in the performance function and converged to its minimum boundary within the specified *** on the adaptive estimation of harmonic amplitude,the torque control law of the motor was obtained by using the filter backstepping method,which prevented the torsional vibration of the system caused by the input fluctuation and avoided the complexity explosion of the controller design,and the stability of the closed-loop system was strictly proved by the Lyapunov *** actual numerical simulation verified the effectiveness of the proposed control strategy.

关键词： Main drive system Torsional vibration Command filter Finite time predetermined performance

SPOROCYTELESS Is a Novel Embryophyte-Specific Transcription Repressor that Interacts with TPL and TCP Proteins in Arabidopsis

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Journal of Genetics and Genomics 2014年第12期41卷 617-625页

作者： guang-Hui Chen jia-Ying Sun Man liu Jie liu Wei-Cai Yang State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental BiologyChinese Academy of Sciences The University of Chinese Academy of Sciences

Germlines in plants are formed de novo during post-embryonic development, while little is known about the mechanism that controls this process. In Arabidopsis, the earliest gene controlling this process is SPOROCYTELESS （SPL）. A decade ago, we showed that loss of SPL function abolished sporogenesis in both male and female organs of Arabidopsis. However, its function is unclear up to now. In this study, we showed that SPL belongs to a novel transcription repressor family specific in embryophyte, which consists of 173 members in the land plants so far. All of them contain a conserved SPL-motif in their N-terminal and an ethylene-responsive element binding factor-associated amphiphilic repression （EAR） motif in the C-terminal, therefore designated as SPL-like, EAR-containing proteins （SPEARs）. Consis- tently, SPL acts as a transcriptional repressor in yeast and tobacco cells, and SPEAR proteins are able to form homodimer and/or het- erodimer with each other in vitro. Furthermore, SPEARs interact with the TOPLESS （TPL） co-repressors via the EAR motif and TCP family transcription factors in yeast cells. Together, we propose that SPL and SPEARs most likely belong to a novel transcription repressor family in land plants which may play a variety of developmental roles in plants.

关键词： Germline specification Sporogenesis SPL Transcription repressor Arabidopsis

Endurance time history analysis of the seismic behavior and performance assessment of hydro-chemo-mechanical degradation-affected hydraulic tunnels with service time

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Underground Space 2024年第4期17卷 207-225页

作者： Benbo Sun Pengxiao Wang Gangqin Zhang Mingjiang deng Weiying liu jia Xu School of Water Conservancy and Transportation Zhengzhou UniversityZhengzhou 450001China Xinjiang Ertix River Basin Development and Construction Management Bureau Urumqi 830000China

Subjected to the coupling action of multiple hazards in hydraulic engineering,hydraulic tunnels may be corroded and damaged to varying degrees during their service lives,which will decrease the seismic performance of these ***,the research and seismic design of significant hydraulic engineering projects focus on investigating the structural response based on the design material parameters,which may overestimate the seismic capacity of structures during their service *** this paper,research is performed to identify the effect of hydro-chemo-mechanical corrosion on the seismic performance of hydraulic tunnels with different burial depths.A plastic damage model of time-varying concrete degradation induced by the hydro-chemo-mechanical effect is first determined and implemented,and the endurance time acceleration records are generated in ***,a study of the endurance time relationship of hydro-chemomechanical corrosion-affected hydraulic tunnels,considering the fluid–structure-surrounding rock interaction systems throughout the service period,is undertaken to directly associate the structural response with the predefined evaluation ***,this research constructs 3D time-varying fragility surfaces considering the hydro-chemo-mechanical effect and seismic *** results show that the relative displacement of hydro-chemo-mechanical corrosion-affected hydraulic tunnels is larger than that of nonaffected hydraulic ***-chemo-mechanical effect-induced material deterioration will lead to an increase in the cumulative damage(crack)area and damage degree of hydraulic ***,the seismic fragility analysis shows that the longer the service time of hydro-chemo-mechanical corrosion-affected hydraulic tunnels,the more likely they are to ***,attention should be given to improving the aseismic capacity of hydro-chemo-mechanical corrosion-affected hydraulic tunnels in future seismic design and performance asses

关键词： Hydro-chemo-mechanical effect Time-varying Hydraulic tunnels Fragility surface

Symplectic analysis for elastic wave propagation in two-dimensional cellular structures

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Acta Mechanica Sinica 2010年第5期26卷 711-720页

作者： Xiu-Hui Hou Zi-Chen deng jia-Xi Zhou Tie-Quan liu Department of Engineering Mechanics Northwestern Polytechnical University Xi'an 710072 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China

On the basis of the finite element analysis, the elastic wave propagation in cellular structures is investigated using the symplectic algorithm. The variation principle is first applied to obtain the dual variables and the wave propagation problem is then transformed into two-dimensional （2D） symplectic eigenvalue problems, where the extended Wittrick-Williams algorithm is used to ensure that no phase propagation eigenvalues are missed during computation. Three typical cellular structures, square, triangle and hexagon, are introduced to illustrate the unique feature of the symplectic algorithm in higher-frequency calculation, which is due to the conserved properties of the structure-preserving symplectic algorithm. On the basis of the dispersion relations and phase constant surface analysis, the band structure is shown to be insensitive to the material type at lower frequencies, however, much more related at higher frequencies. This paper also demonstrates how the boundary conditions adopted in the finite element modeling process and the structures＇ configurations affect the band structures. The hexagonal cells are demonstrated to be more efficient for sound insulation at higher frequencies, while the triangular cells are preferred at lower frequencies. No complete band gaps are observed for the square cells with fixed-end boundary conditions. The analysis of phase constant surfaces guides the design of 2D cellular structures where waves at certain frequencies do not propagate in specified directions. The findings from the present study will provide invaluable guidelines for the future application of cellular structures in sound insulation.

关键词： Cellular structures Symplectic analysis Dispersion relation - Phase constant surface Sound insulation

Shuttle-run synchronization in mobile ad hoc networks

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Frontiers of physics 2015年第3期10卷 105-112页

作者： Sheng-Fei Ma Hong-Jie Bi Yong Zou zong-Hua liu Shu-guang Guan Department of Physics East China Normal University Shanghai 200241 China State Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China

In this work, we study the collective dynamics of phase oscillators in a mobile ad hoc network whose topology changes dynamically. As the network size or the communication radius of individual oscillators increases, the topology of the ad hoc network first undergoes percolation, forming a giant cluster, and then gradually achieves global connectivity. It is shown that oscillator mobility generally enhances the coherence in such networks. Interestingly, we find a new type of phase synchronization/clustering, in which the phases of the oscillators are distributed in a certain narrow range, while the instantaneous frequencies change signs frequently, leading to shuttle-run-like motion of the oscillators in phase space. We conduct a theoretical analysis to explain the mechanism of this synchronization and obtain the critical transition point.

关键词： synchronization phase transition ad hoc network

Entrapment of the temporal horn secondary to postoperative gamma-knife radiosurgery in intraventricular meningioma: A case report

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World Journal of Clinical Cases 2019年第18期7卷 2894-2898页

作者： jia liu Sheng-Rong Long guang-Yu Li Department of Neurosurgery the First Hospital of China Medical University

BACKGROUND Entrapment of the temporal horn (ETH) is a rare pathologic condition. It is a kind of focal hydrocephalus caused by obstruction of flow pathway of cerebrospinal fluid. It is caused by various conditions, but ETH secondary to postoperative gamma-knife radiosurgery (GKS) is extremely rare. CASE SUMMARY A 52-year old previously healthy woman underwent resection of a large intraventricular meningioma. A small fragment of residual tumor with no obvious enlargement of the temporal horn was observed 3 mo after surgery, and she was referred for GKS. Two months after GKS, she complained of headache and progressive paralysis of the left limb. Magnetic resonance imaging revealed enlargement of the temporal horn. There was a second procedure to resect the residual tumor 8 mo after GKS. After the second procedure, she recovered smoothly. As of the date of this writing, she has remained in good condition. CONCLUSION This case reminds us that ETH should be considered in the treatment of intraventricular meningiomas, especially before GKS.

关键词： Entrapment of the temporal horn Gamma-knife radiosurgery Intraventricular meningioma Case report

负载骨形态发生蛋白2水凝胶诱导牙髓干细胞的成骨分化

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中国组织工程研究 2025年第16期29卷 3301-3310页

作者：伊斯拉尔古丽·麦麦提贾森刘佳新疆医科大学第一附属医院(附属口腔医院)儿童口腔科-口腔预防科新疆维吾尔自治区乌鲁木齐市830054 西安医学院口腔医学院陕西省西安市710021 新疆维吾尔自治区口腔医学研究所新疆维吾尔自治区乌鲁木齐市830054

背景:前期研究证明,甲基丙烯酸酐改性明胶/经处理牙本质基质复合水凝胶支架可促进人牙髓干细胞的增殖及分化。水凝胶负载骨形态发生蛋白2被认为是骨修复中有前景的材料。目的:观察负载不同质量浓度骨形态发生蛋白2的甲基丙烯酸酐改性明... 详细信息

背景:前期研究证明,甲基丙烯酸酐改性明胶/经处理牙本质基质复合水凝胶支架可促进人牙髓干细胞的增殖及分化。水凝胶负载骨形态发生蛋白2被认为是骨修复中有前景的材料。目的:观察负载不同质量浓度骨形态发生蛋白2的甲基丙烯酸酐改性明胶/经处理牙本质基质复合水凝胶对人牙髓干细胞成骨向分化的诱导作用。方法:制备含0,50,100,200μg/mL骨形态发生蛋白2的甲基丙烯酸酐改性明胶/经处理牙本质基质复合水凝胶,分别记为GelMA/TDM、BMP-2(50 ng/mL)GelMA/TDM、BMP-2(100 ng/mL)GelMA/TDM、BMP-2(200 ng/mL)GelMA/TDM,检测复合水凝胶对骨形态发生蛋白2的体外缓释性能。采用改良组织块酶消化法提取人牙髓干细胞,分别接种于4种水凝胶表面,采用CCK-8法检测细胞增殖,DAPI染色检测细胞黏附;对各组水凝胶表面的人牙髓干细胞进行成骨诱导,进行碱性磷酸酶染色、碱性磷酸酶活性检测与茜素红染色,采用RT-PCR法检测相关成骨基因(Runx2、骨形态发生蛋白2、骨桥蛋白、骨钙素、Ⅰ型胶原)表达。结果与结论:①甲基丙烯酸酐改性明胶/经处理牙本质基质复合水凝胶可持续释放骨形态发生蛋白2长达21 d,在第3-6天释放较快,第6天之后释放趋于平稳;②4种水凝胶均可促进人牙髓干细胞的增殖,其中以BMP-2(100 ng/mL)-GelMA/TDM复合水凝胶的作用最明显;相较于GelMA/TDM复合水凝胶,BMP-2-GelMA/TDM复合水凝胶可促进人牙髓干细胞的黏附,其中以BMP-2(200 ng/mL)-GelMA/TDM复合水凝胶的作用最明显;③相较于GelMA/TDM复合水凝胶,BMP-2-GelMA/TDM复合水凝胶可提升碱性磷酸酶活性、钙结节含量与相关成骨基因表达,综合分析显示BMP-2(100 ng/mL)-GelMA/TDM复合水凝胶的作用更明显;④结果表明,BMP-2(100 ng/mL)-GelMA/TDM复合水凝胶促进牙髓干细胞成骨向分化的能力更明显。

关键词：人牙髓干细胞骨形态形成蛋白2 细胞增殖细胞分化组织工程牙髓-牙本质再生

Effect of Asynchronous Adjustments of Clamping Cylinders on Triangular Crack of Slab Castings Under Application of Soft Reduction

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Journal of Iron and Steel Research International 2013年第2期20卷 38-47页

作者： liu Ke CHANG Yun-he HAN Zhan-guang ZHANG jia-quan State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological EngineeringUniversity of Science and Technology Beijing

Soft reduction is known to be one of the best ways to improve the internal quality of slab castings such as center segregation, center porosity, centerline or triangular zone cracks, which is based on a proper adoption of the amount of reduction upon the given final solidification zone through roll gap adjustments. The synchronization of the clamping cylinders for roll gap adjustments should be very important to the application of soft reduction, including the synchronization of the clamping cylinders adjustments in the same and different segments. The synchronization of clamping cylinders adjustments is mainly affected by the adjustable accuracy of the four position-controlled clamping cylinders mounted in the upper frames of the segments according to a predetermined transformation relationship between the signals of displacement sensors and aimed roll gap, which, however, is also influenced by the installation accuracy, the precision of displacement sensors, the deformation of the segment frames and/or its bearing pedestals. Due to the actual asynchronous adjustments of the four clamping cylinders, the dynamic soft reduction operation is normally applied at non-ideal mechanical conditions. Here 7 possible situations of asynchronous adjustments of the local segments which may induce gap deviation have been presented. The roll gap deviation in the soft reduction region of a slab casting has been studied by a 3-D visco-elastic plastic FEM model, through which the additional inter-roll bulging, the related triangular cracks induced by one kind of the possible asynchronous adjustment situation and the effectiveness of soft reduction have been analyzed. A critical tolerance for the gap adjustments has been proposed for better contribution of soft reduction to the internal quality of slabs.

关键词： slab casting soft reduction clamping cylinder asynchronous adiustment

Shear-thickening behavior of Fe-ZSM5 zeolite slurry and its removal with alumina/boehmites

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International Journal of Minerals,Metallurgy and Materials 2018年第6期25卷 682-688页

作者： Xiao-guang liu Yan Li Wen-dong Xue jia-lin Sun Qian Tang Department of Inorganic Nonmetallic Materials School of Materials Science and Engineering University of Science and Technology Beijing Atmospheric Environment Department Chinese Academy for Environmental Planning

A cryogenic scanning electron microscopy（cryo-SEM） technique was used to explore the shear-thickening behavior of Fe-ZSM5 zeolite pastes and to discover its underlying mechanism. Bare Fe-ZSM5 zeolite samples were found to contain agglomerations, which may break the flow of the pastes and cause shear-thickening behaviors. However, the shear-thickening behaviors can be eliminated by the addition of halloysite and various boehmites because of improved particle packing. Furthermore, compared with pure Fe-ZSM5 zeolite samples and its composite samples with halloysite, the samples with boehmite（Pural SB or Disperal） additions exhibited network structures in their cryo-SEM images; these structures could facilitate the storage and release of flow water, smooth paste flow, and avoid shear-thickening. By contrast, another boehmite（Versal 250） formed agglomerations rather than network structures after being added to the Fe-ZSM5 zeolite paste and resulted in shear-thickening behavior. Consequently, the results suggest that these network structures play key roles in eliminating the shear-thickening behavior.

关键词： Fe-ZSM5 zeolite cryogenic scanning electron microscopy shear-t^ickening behavior zeta potential boel^nite