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Isolation performances and optimization of triple quasi-zero stiffness isolators

Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 124-141页

作者： Yuntian Zhang Guangnan Zhu qingjie cao School of Astronautics Harbin Institute of TechnologyHarbin 150001China

In this paper,triple quasi-zero stiffness(QZS)passive vibration isolators whose restoring force curve has a three-stage softening effect are ***-coupled SD oscillators with three independent geometrical parameters are used as negative stiffness mechanisms to achieve QZS characteristics at the origin and symmetrical positions on both sides of the *** performances of different triple QZS isolators are analyzed to show influences of the selection of QZS regions away from the origin on the range of isolation *** optimizations of system parameters are carried out to get a larger range of small restoring force regions and small stiffness *** performances of two triple QZS isolators are discussed to show the influence of different Pareto optimization solutions through the comparisons with single and double QZS *** showed that triple QZS isolators have both the advantages of single and double QZS isolators which results in better isolation performances under both small and large excitation *** improvement in isolation performances for triple QZS isolators is found with the decrease in average stiffness due to the appearance of two symmetrical QZS regions away from the *** displacements of QZS regions away from the origin result in better isolation performances when excitation amplitude is large,and triple QZS characteristics are similar to double QZS isolators at this *** restoring forces of QZS regions away from the origin lead to better isolation performances when excitation amplitude is small,and triple QZS characteristics are similar to single QZS isolators at this *** with the decrease in average stiffness,the improvement of isolation performances shows a hysteresis phenomenon due to the difference between static and dynamic characteristics.

关键词： triple quasi-zero stiffness vibration isolation Pareto optimization force transmissibility geometrical nonlinear

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Effects of simulated gut pH environment on bacterial composition and pheromone production of Dendroctonus valens

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Insect Science 2024年第1期31卷 225-235页

作者： qingjie cao Yu Zhao Tuuli-Marjaana Koski Huiping Li Jianghua Sun College of Forestry Hebei Agricultural UniversityBaodingHebei ProvinceChina State Key Laboratory of Integrated Management of Pest Insects and Rodents Institute of ZoologyChinese Academy of SciencesBeijingChina College of Life Science/Hebei Basic Science Center for Biotic Interactions Institute of Life Science and Green DevelopmentHebei UniversityBaodingHebei ProvinceChina

Bark beetles are an economically and ecologically important insect group,with aggregation behavior and thus host colonization success depends on pheromone-mediated *** some species,such as the major invasive forest pest in China,red turpentine beetle(Dendroctonus valens),gut microbiota participates in pheromone production by converting tree monoterpenes into pheromone ***,how variation in gut microenvironment,such as pH,affects the gut microbial composition,and consequently pheromone production,is *** this study,we fed wild caught *** with 3 different pH media(main host diet with natural pH of 4.7;a mildly acidic diet with pH 6 mimicking the beetle gut pH;and highly acidic diet with pH 4),and measured their effects on the gut pH,bacterial community and production of the main aggregation and anti-aggregation pheromone(verbenone).We further tested the verbenone production capacity of 2 gut bacterial isolates in different pH environments(pH 6 and 4).Compared to natural state or main host diet,feeding on less acidic diet(pH 6)diluted the acidity of the gut,whereas feeding on highly acidic diet(pH 4)enhanced *** changes in gut pH reduced the abundance of dominant bacterial genera,resulting in decreased verbenone ***,the highest pheromone conversion rate of the bacterial isolates was observed in pH mimicking the acidity in beetle *** together,these results indicate that changes in gut pH can affect gut microbiota composition and pheromone production,and may therefore have the potential to affect host colonization behavior.

关键词： Dendroctonus valens gut bacteria gut pH verbenone

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基于双流Transformer结构的多能计算机断层扫描成像投影数据去噪方法

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激光与光电子学进展 2024年第8期61卷 399-408页

作者：欧阳顺馨史再峰孔凡宁张丽丽曹清洁天津大学微电子学院天津300072 天津师范大学数学科学学院天津300387 天津市成像与感知微电子技术重点实验室天津300072

多能计算机断层扫描(Computed tomography,CT)技术可以更加精确地分辨出人体组织对不同能量X射线光子的吸收情况,是医学成像领域的重要发展方向。为了解决因量子噪声等非理想效应加重导致重建图像质量急剧退化的问题,提出了一种基于移... 详细信息

多能计算机断层扫描(Computed tomography,CT)技术可以更加精确地分辨出人体组织对不同能量X射线光子的吸收情况,是医学成像领域的重要发展方向。为了解决因量子噪声等非理想效应加重导致重建图像质量急剧退化的问题,提出了一种基于移位窗口多头自注意力机制的双流Transformer网络结构。该结构利用移位窗口Transformer和局部增强窗口Transformer分别提取投影数据的全局和局部特征,充分利用投影数据的非局部自相似性以保留投影数据的内部结构;然后通过残差卷积融合提取的特征;最后使用带有非局部全变分的混合损失函数来监督网络模型的训练,提升该网络模型对投影数据内部细节的敏感程度。实验结果表明,所提方法处理后的重建图像峰值信噪比(PSNR)值、结构相似性(SSIM)值和特征相似度(FSIM)值分别达到37.7301 dB、0.9944和0.9961。与目前先进的多能CT去噪方法相比,所提方法在去除低剂量多能CT投影数据噪声的同时,可保留更多的细节特征,有利于后续的精确诊断。

关键词：图像处理计算机断层扫描成像低剂量卷积神经网络 Transformer网络

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锥辊平盘形立磨的辊套夹角和R角对工况的影响分析

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水泥 2024年第3期 59-61页

作者：曹庆杰王双志张伯超康春生冀东水泥滦州有限责任公司河北唐山063708 唐山冀东水泥股份有限公司河北唐山064000

在熟料单位产品综合电耗中,原料系统占比在1/3以上,电耗的影响很多,其中锥辊平盘形立磨辊套大端外R角半径如果没有进行合理定制,会导致粉磨设备效率未达最佳状态,造成熟料单位产品综合电耗上升。本文就滦州公司辊套小端夹角在15°、13... 详细信息

在熟料单位产品综合电耗中,原料系统占比在1/3以上,电耗的影响很多,其中锥辊平盘形立磨辊套大端外R角半径如果没有进行合理定制,会导致粉磨设备效率未达最佳状态,造成熟料单位产品综合电耗上升。本文就滦州公司辊套小端夹角在15°、13°和大端外R角半径在R40、R80、R60时,粉磨做功效率、能耗方面和相关选型因素的一些研究与实践工作进行了叙述、总结。

关键词：立磨辊套R角辊套夹角工况

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The effect of inactivation of aldehyde dehydrogenase on pheromone production by a gut bacterium of an invasive bark beetle,Dendroctonus valens

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Insect Science 2023年第2期30卷 459-472页

作者： qingjie cao Tuuli-Marjaana Koski Huiping Li Chi Zhang Jianghua Sun College of Forestry Hebei Agricultural UniversityBaodingHebei ProvinceChina College of Life Science Institute of Life Science and Green DevelopmentHebei UniversityBaodingHebei ProvinceChina State Key Laboratory of Integrated Management of Pest Insects and Rodents Institute of ZoologyChinese Academy of SciencesBeijingChina Rural Energy and Environment Agency Ministry of AgricultureandRural AffairsBeijingChina

Semiochemical-based management strategies are important for controlling bark beetles,such as invasive Red Turpentine Beetle(Denroctonus valens),the causal agent for mass mortality of pine trees(Pinus spp.)in *** has been previously shown that the pheromone verbenone regulates the attack density of this beetle in a dose-dependent manner and that the gut bacteria of *** are involved in verbenone ***,molecular functional verification of the role of gut bacteria in the pheromone production of *** is still *** better understand the molecular function of gut bacterial verbenone production,we chose a facultative anaerobic gut bacterium(Enterobacter xiangfangensis)of *** based on its strong ability to convert cis-verbenol to verbenone,as shown in our previous study,and investigated its transcriptomics in the presence or absence of cis-verbenol under anaerobic conditions(simulating the anoxic environment in the beetle's gut).Based on this transcriptome analysis,aldehyde dehydrogenase(ALDH1)was identified as a putative key gene responsible for verbenone production and was knocked-down by homologous recombination to obtain a mutant *** *** results show that these mutants had significantly decreased the ability to convert the monoterpene precursor to verbenone compared with the wild-type bacteria,indicating that ALDH1 is primarily responsible for verbenone conversion for this bacterium *** findings provide further mechanistic evidence of bacterially mediated pheromone production by ***,add new perspective for functional studies of gut bacteria in general,and may aid the development of new gene silencing-based pest management strategies.

关键词： aldehyde dehydrogenase Dendroctonus valens gut bacteria mutants transcriptome verbenone

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Bifurcation analysis for vibrations of a turbine blade excited by air flows

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Science China(Technological Sciences) 2016年第8期59卷 1217-1231页

作者： WANG Dan CHEN YuShu HAO ZhiFeng cao qingjie School of Astronautics Harbin Institute of Technology Harbin 150001 China

模仿汽轮机片和即将来临的空气流动的液体结构相互作用(FSI ) 的一个减少的 three-degree-of-freedom 模型被建议。运动的方程由联合弯曲和片以及代表的货车 der Pol 摆动的扭转组成液体变化时间。1:1 系统的内部回声与多重规模方法被... 详细信息

模仿汽轮机片和即将来临的空气流动的液体结构相互作用(FSI ) 的一个减少的 three-degree-of-freedom 模型被建议。运动的方程由联合弯曲和片以及代表的货车 der Pol 摆动的扭转组成液体变化时间。1:1 系统的内部回声与多重规模方法被分析，并且调整方程被导出。二参数的分叉图被计算。包括 detuning 参数和减少的频率，系统参数的效果在结构和液体的回答上被调查。分叉曲线被计算，稳定性被检验 Jacobian 矩阵的特征值决定。结果显示包括僵绳的不变的解决方案的富有的动态现象 -- 节点和 Hopf 分叉能发生在某些参数条件下面。不稳定的答案发生的参数区域应该被避免保留片的安全操作。分析答案被直接数字的模拟验证。

关键词：叶片振动分岔分析涡轮叶片空气流动流体结构相互作用激励运动方程多尺度分析

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Bifurcation and dynamic response analysis of rotating blade excited by upstream vortices

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Applied Mathematics and Mechanics(English Edition) 2016年第9期37卷 1251-1274页

作者： Dan WANG Yushu CHEN M.WIERCIGROCH qingjie cao School of Astronautics Harbin Institute of Technology Centre for Applied Dynamics Research School of Engineering University of AberdeenKing's College

A reduced model is proposed and analyzed for the simulation of vortexinduced vibrations （VIVs） for turbine blades. A rotating blade is modelled as a uniform cantilever beam, while a van der Pol oscillator is used to represent the time-varying characteristics of the vortex shedding, which interacts with the equations of motion for the blade to simulate the fluid-structure interaction. The action for the structural motion on the fluid is considered as a linear inertia coupling. The nonlinear characteristics for the dynamic responses are investigated with the multiple scale method, and the modulation equations are derived. The transition set consisting of the bifurcation set and the hystere- sis set is constructed by the singularity theory and the effects of the system parameters, such as the van der Pol damping. The coupling parameter on the equilibrium solutions is analyzed. The frequency-response curves are obtained, and the stabilities are determined by the Routh-Hurwitz criterion. The phenomena including the saddle-node and Hopf bifurcations are found to occur under certain parameter values. A direct numerical method is used to analyze the dynamic characteristics for the original system and verify the va- lidity of the multiple scale method. The results indicate that the new coupled model is useful in explaining the rich dynamic response characteristics such as possible bifurcation phenomena in the VIVs.

关键词： vortex-induced vibration van der Pol oscillator dynamic response tran-sition set singularity theory bifurcation phenomenon

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A novel smooth and discontinuous oscillator with strong irrational nonlinearities

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Science China(Physics,Mechanics & Astronomy) 2012年第10期55卷 1832-1843页

作者： HAN YanWei cao qingjie CHEN YuShu WIERCIGROCH Marian School of Astronautics Harbin Institute and TechnologyHarbin 150001China Department of Mathematics and Physics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Centre for Applied Dynamics Research School of EngineeringUniversity of AberdeenKing's CollegeAberdeen AB243UEScotlandUK

In this paper,we propose a novel nonlinear oscillator with strong irrational nonlinearities having smooth and discontinuous characteristics depending on the values of a smoothness *** oscillator is similar to the SD oscillator,originally introduced in Phys Rev E 69(2006).The equilibrium stability and the complex bifurcations of the unperturbed system are *** bifurcation sets of the equilibria in parameter space are constructed to demonstrate transitions in the multiple well dynamics for both smooth and discontinuous *** Melnikov method is employed to obtain the analytical criteria of chaotic thresholds for the singular closed orbits of homoclinic,homo-heteroclinic,cuspidal heteroclinic and tangent homoclinic orbits of the perturbed system.

关键词：非线性振子不连续振荡器光滑 Melnikov方法非理性器具平滑参数

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A two degree of freedom stable quasi-zero stiffness prototype and its applications in aseismic engineering

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Science China(Technological Sciences) 2020年第3期63卷 496-505页

作者： ZHU GuangNan LIU JiYe cao qingjie CHENG YongFeng LU ZhiCheng ZHU ZhuBing School of Astronautics Harbin Institute of TechnologyHarbin 150001China China Electric Power Research Institute Beijing 100055China

In this paper, an archetypal aseismic system is proposed with 2-degree of freedom based on a smooth and discontinuous(SD)oscillator to avoid the failure of electric power system under the complex excitation of seismic waves. This model comprises two vibration isolation units for the orthogonal horizontal directions, and each of them admits the stable quasi-zero stiffness(SQZS)with a pair of inclined linear elastic springs. The equation of motion is formulated by using Lagrange equation, and the SQZS condition is obtained by optimizing the parameters of the system. The analysis shows that the system behaves a remarkable vibration isolation performance with low resonant frequency and a large stroke of SQZS interval. The experimental investigations are carried out to show a high sonsistency with the theoretical results, which demonstrates the improvement of aseismic behavior of the proposed model under the seismic wave.

关键词： SD oscillator two-DOF vibration isolation stable quasi-zero stiffness low-frequency vibration isolation aseismic experiment

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The Partial Stability for Linear Discrete Systems

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数学研究与评论 1989年第4期9卷 541-545页

作者： cao qingjie(Qufu Normal University) 曲阜师范大学山东曲阜

In this paper, we study the partial stability of linear discrete systems by means of Liapunov’s functions of quadratic form. We obtain a necessary and sufficient condition for the system being stable with respect to part of variables and generalize Liapunov’s equation to the partial stability of linear discrete systems. A method of constructing Liapunov’s function of quadratic form for the stability of the systems is given.

关键词： The Partial Stability for Linear Discrete Systems

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