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Separate Control of High Frequency Electro-hydraulic Vibration Exciter

Chinese Journal of Mechanical Engineering 2011年第2期24卷 293-302页

作者： JIA Wen＇ang RUAN Jian ren Yan The Key Laboratory of Mechanical Manufacture and Automation of Ministry of Education Zhejiang University of Technology Hangzhou 310032 China

The working frequency of the conventional electro-hydraulic vibration exciters,which consist of a servo valve and a hydraulic cylinder,is generally restricted within a narrow range due to limited frequency response capability of the servo valve *** counteract such restriction,a novel scheme for an electro-hydraulic vibrator,controlled by a two-dimensional valve（2D valve） and a bias valve in parallel,is therefore *** frequency,amplitude and offset are independently controlled by rotary speed,axial sliding of the spool of the 2D valve and axial sliding of the spool of the bias *** principle of separate control was presented and the regulation approach of frequency,amplitude and offset was discussed.A mathematical model of the hydraulic power mechanism for the proposed vibration exciter was established to investigate the relationship between the amplitude and the axial sliding of the 2D valve＇ spool,as well as that between the offset and the axial sliding of the bias valve＇s spool at various *** experimental system was built to validate the theoretical *** is verified that the 2D exciter is capable of working smoothly in a frequency range of 5- 200 *** its frequency,amplitude and offset can be controlled respectively by either closed loop or open loop *** is a linear relationship between the output amplitude and the spool axial opening of the 2D valve until a point when the flow rate becomes saturate and the amplitude remains *** offset displacement of the cylinder＇s piston is linearly proportional to the axial displacement of the spool of the bias valve,when the valve opening is less than 25%.Thereafter,the slop of the offset curve decreases and tends to *** proposed electro-hydraulic vibration controlled by the 2D valve not only facilitates the realization of high-frequency electro-hydraulic vibration,the high-accuracy of vibration can also be achieved by means of independent controls to the freque

关键词： control valves electro-hydraulic system vibration exciter dynamics characteristics

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基于边缘计算的电子井盖异常检测技术优化

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粘接 2024年第7期51卷 177-180页

作者：任昂苏菲邵帅王兴振国网山东省电力有限公司山东济南250012

针对电子井盖的异常数据检测问题,研究提出了基于边缘计算的处理方式,提高电子井盖系统的运算效率。对边缘计算的数据处理方法进行优化,利用时空相关性相结合的方式,大大提高边缘计算的异常数据检测效率。实验结果表明,将所提算法与其... 详细信息

针对电子井盖的异常数据检测问题,研究提出了基于边缘计算的处理方式,提高电子井盖系统的运算效率。对边缘计算的数据处理方法进行优化,利用时空相关性相结合的方式,大大提高边缘计算的异常数据检测效率。实验结果表明,将所提算法与其他算法进行对比,该算法在1000个传感器的数据上,本文算法的运行时间约为0.25 s,远远优于其他算法,在电池能耗、数据传输方面同样优势明显。在井盖位移和水位测试等方面,电子井盖的误报率低于2%,具有重要的应用价值。

关键词：边缘计算电子井盖时空相关性数据异常检测

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Recent progress in single crystal perovskite X-ray detectors

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Science China(Information Sciences) 2024年第3期67卷 5-19页

作者： Xiao LIU Jun ren Yu-ang CHEN Xiangshun GENG Dan XIE Tian-Ling ren School of Integrated Circuits Tsinghua University Beijing National Research Center for Information Science and Technology (BNRist)

Perovskites have attracted extensive attention as radiation detection material due to their long carrier diffusion length and lifetime, high absorption coefficient, and flexible manufacturing process. Compared with polycrystalline structures, single crystal perovskites improve the performance of optoelectronic devices due to their low defect state density, better photoelectric characteristics, and chemical ***, we review the recent progress of single crystal perovskite X-ray detectors. First, we briefly introduced the basic concepts, detection mechanisms, figure of merits of perovskite X-ray detectors, and the preparation methods of single crystal perovskites. Then, we summarized the significant advancements in single crystal perovskite X-ray detectors in recent times. Finally, we discussed the critical challenges and some practicable solutions for developing high-performance X-ray detectors.

关键词： single crystal perovskites carrier transport radiation detection X-ray detectors X-ray imaging

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Secure state estimation for cyber-physical systems with unknown input sliding mode observer

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Control Theory and Technology 2024年第2期22卷 244-253页

作者： Panpan Zhang Yuwei ren Yixian Fang ang Liu School of Information Science and Engineering Shandong Normal UniversityJinan250358ShandongChina School of Information Engineering Shandong Management UniversityJinan250357ShandongChina

In recent years, cyber attacks have posed great challenges to the development of cyber-physical systems. It is of great significance to study secure state estimation methods to ensure the safe and stable operation of the system. This paper proposes a secure state estimation for multi-input and multi-output continuous-time linear cyber-physical systems with sparse actuator and sensor attacks. First, for sparse sensor attacks, we propose an adaptive switching mechanism to mitigate the impact of sparse sensor attacks by filtering out their attack modes. Second, an unknown input sliding mode observer is designed to not only observe the system states, sensor attack signals, and measurement noise present in the system but also counteract the effects of sparse actuator attacks through an unknown input matrix. Finally, for the design of an unknown input sliding mode state observer, the feasibility of the observing system is demonstrated by means of Lyapunov functions. Additionally, simulation experiments are conducted to show the effectiveness of this method.

关键词： Sparse attacks Cyber-physical systems Unknown input sliding mode Secure state estimation Adaptive switching mechanism

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The Hydrodynamic Limit of Nonlinear Fokker-Planck Equation

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Journal of Applied Mathematics and Physics 2020年第11期8卷 2488-2499页

作者： Yi’ang ren Lijuan Yu Jie Liao Department of Mathematics East China University of Science and Technology Shanghai China

The non-linear Fokker-Planck equation arises in describing the evolution of stochastic system, which is a variant of the Boltzmann equation modeling the evolution of the random system with Brownian motion, where the collision term is replaced by a drift-diffusion operator. This model conserves mass, momentum and energy;the dissipation is much weaker than that in a simplified model we considered before which conserved only mass, thus more difficult to analyze. The macro-micro decomposition of the solution around the local Maxwellian introduced by T.-P. Liu, T. Yang and S.-H. Yu for Boltzmann equation is used, to reformulate the model into a fluid-type system incorporate viscosity and heat diffusion terms, coupled with an equation of the microscopic part. The viscosity and heat diffusion terms can give dissipative mechanism for the analysis of the model.

关键词： Non-Linear Fokker-Planck Equation Macro-Micro Decomposition Fluid-Type System Viscosity Heat Diffusion

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Effects of longitudinal magnetic field on primary dendrite spacing and segregation of directionally solidified single crystal superalloy

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Progress in Natural Science:Materials International 2024年第1期34卷 26-36页

作者： Congjiang Zhang Yilin Zhou Chen Shen Weili ren Xiaotan Yuan Biao Ding Haibiao Lu Zuosheng Lei Yunbo Zhong ang Zhang State Key Laboratory of Advanced Special Steel College of Materials Science and Engineering Shanghai University National Engineering Research Center for Magnesium Alloys Natural Key Laboratory of Advanced Casting Technologies College of Materials Science and EngineeringChongqing University

The primary dendrite spacing(PDS) and segregation of directionally solidified single crystal(SC) superalloy under the longitudinal magnetic field(LMF) were investigated based on the analysis of the whole cross-sectional microstructure at different solidification distances. The results show that the PDS under the LMF remains basically unchanged at different solidification distances, and it is greater than that under no LMF. With the increase of magnetic field intensity, the PDS increases and the macrosegregation decreases. The increasing PDS and reducing segregation under the LMF can be attributed to the increase of solute boundary layer, which expands the non-equilibrium freezing temperature range and brings the effective partition coefficient closer to 1. The increase of the solute enrichment layer thickness could be caused by the downward secondary circulation generated by the thermoelectric magnetic convection(TEMC) near the interface, which drives the migration of solutes towards the interdendritic region. This work not only clarifies the mechanism of LMF controlling PDS and reducing segregation by TEMC, but also provides theoretical guidance for producing high-quality SC superalloys using magnetic fields.

关键词： Primary dendrite spacing Segregation Single crystal superalloy Directional solidification Magnetic field Thermoelectric magnetic convection

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Joint Active and Passive Beamforming Design in Intelligent Reflecting Surface (IRS)-Assisted Covert Communications:A Multi-Agent DRL Approach

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China Communications 2024年第9期 11-26页

作者： Gao ang ren Xiaoyu Deng Bin Sun Xinshun Zhang Jiankang School of Electronic Information Northwestern Polytechnical University Key Laboratory of Near Ground Detection and Perception Technology Department of Computing and Informatics Bournemouth University

Intelligent Reflecting Surface(IRS),with the potential capability to reconstruct the electromagnetic propagation environment,evolves a new IRSassisted covert communications paradigm to eliminate the negligible detection of malicious eavesdroppers by coherently beaming the scattered signals and suppressing the signals ***,when multiple IRSs are involved,accurate channel estimation is still a challenge due to the extra hardware complexity and communication *** the crossinterference caused by massive reflecting paths,it is hard to obtain the close-formed solution for the optimization of covert *** this basis,the paper improves a heterogeneous multi-agent deep deterministic policy gradient(MADDPG) approach for the joint active and passive beamforming(Joint A&P BF) optimization without the channel estimation,where the base station(BS) and multiple IRSs are taken as different types of agents and learn to enhance the covert spectrum efficiency(CSE) *** to the 'centralized training and distributed execution' feature of MADDPG,each agent can execute the active or passive beamforming inde pendently based on its partial observation without referring to *** results demonstrate that the proposed deep reinforcement learning(DRL) approach could not only obtain a preferable CSE of legitimate users and a low detection of probability(LPD)of warden,but also alleviate the communication overhead and simplify the IRSs deployment.

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Nitric oxide involved in regulating HS induced GA biosynthesis via inhibition of aconitase in Ganoderma lucidum

Nitric oxide involved in regulating HS induced GA biosynthes...

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多彩菌物美丽中国——中国菌物学会2019年学术年会

作者： Rui Liu ang ren Liang Shi Jing Zhu Mingwen Zhao Key Laboratory of Agricultural Environmental Microbiology Ministry of AgricultureMicrobiology Department College of Life Sciences Nanjing Agricultural University

Ganoderma lucidum（G. lucidum） is one of the best-known medicinal basidiomycetes in the world,because it containing a wide range of immuno-modulatory and bioactive compounds. Ganoderic acid（GA） is one of the major secondary metabolites in G. lucidum, a basidiomycete with high commercial value. Previous studies have shown that heat stress（HS） increases GA biosynthesis via induced reactive oxygen species（ROS）accumulation in G. lucidum[1] and NO relieves HS-induced GA accumulation in G. lucidum[2]. To determine the mechanism that NO relieves HS-induced GA accumulation in G. lucidum, the effect of NO on the ROS content was examined under heat treatment. The results showed that NO decreased the production of MitROS under heat treatment. Further research found that NO reduced the MitROS content through inhibit the aconitase activity. In the aconitase silenced strains（Aconi）, treatment with NO donor（SNP） showed no obviously effect on the mitROS and GA content relative to the untreated sample. Combined with the prior results, these findings indicate that NO inhibits aconitase activity to reduced mitROS content and thereby relieved HS-induced GA overproduction in Ganoderma *** S-nitrosylation, the incorporation of a nitroso group to a Cys thiol, has been established as a significant route through which NO transmits its global cellular influence. To study the mechanism of the inhibition of the aconitase activity in G. lucidum, the aconitase proteins S-Nitrosylation was ***-switch technology（BST） and mass spectrometric analysis revealed that Acon was S-nitrosylated at amino acid residues, Cys 594. The substitution of Cys 594 with non-nitrosylatable Ser with site-directed mutagenesis causes the abolishes its responsiveness to the NO-reducted enzymatic activity. These findings demonstrate that NO inhibited the activity of aconitase through S-nitrosylation at Cys 594 thereby relieved HS-induced GA biosynthesis in Ganoderma lucidum..

关键词： Nitric oxide Heat stress Ganoderic Acid Aconitase S-Nitrosylation

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SA inhibits complex Ⅲ activity to generate reactive oxygen species and thereby induces GA overproduction in Ganoderma lucidum

SA inhibits complex Ⅲ activity to generate reactive oxygen ...

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中国菌物学会2018年学术年会

作者： Rui Liu ang ren Liang Shi Jing Zhu Mingwen Zhao Key Laboratory of Agricultural Environmental Microbiology Ministry of AgricultureMicrobiology DepartmentCollege of Life SciencesNanjing Agricultural University

Ganoderma lucidum has high commercial value because it produces many active compounds, such as ganoderic acids（GAs）. Salicylic acid（SA） was previously reported to induce the biosynthesis of GA in G. lucidum. In this study, we found that SA induces GA biosynthesis by increasing ROS production, and further research found that NADPH oxidase-silenced strains exhibited a partial reduction in the response to SA, resulting in the induction of increased ROS production. Furthermore, the localization of ROS shows that mitochondria are sources of ROS production in response to SA treatment. An additional analysis focused on the relationship between SA-induced ROS production and mitochondrial functions, and the results showed that inhibitors of mitochondrial complexes I and II exert approximately 40–50% superimposed inhibitory effects on the respiration rate and H2O2 content when co-administered with SA. However, no obvious superimposed inhibition effects were observed in the sample co-treated with mitochondrial complex III inhibitor and SA, implying that the inhibitor of mitochondrial complex III and SA might act on the same site in mitochondria. Additional experiments revealed that complex III activity was decreased 51%, 62% and 75% after treatment with 100, 200, and 400?μM SA, respectively. Our results highlight the finding that SA inhibits mitochondrial complex III activity to increase ROS generation. In addition, inhibition of mitochondrial complex III caused ROS accumulation, which plays an essential role in SA-mediated GA biosynthesis in G. lucidum. This conclusion was also demonstrated in complex III-silenced strains. To the best of our knowledge, this study provides the first demonstration that SA inhibits complex III activity to increase the ROS levels and thereby regulate secondary metabolite biosynthesis.

关键词： Salicylic acid Reactive oxygen species Mitochondrial complex Ⅲ Ganoderic acids

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Negative enthalpy alloys and local chemical ordering:a concept and route leading to synergy of strength and ductility

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National Science Review 2024年第4期11卷 172-184页

作者： Zibing An Tao Yang Caijuan Shi Shengcheng Mao Lihua Wang ang Li Wei Li Xianmeng Xue Ming Sun Yifan Bai Yapeng He Fuzeng ren Zhouguang Lu Ming Yan Yang ren Chain-Tsuan Liu Ze Zhang Xiaodong Han Beijing Key Lab of Microstructure and Property of Advanced Materials College of Materials Science &Engineering Beijing University of Technology Department of Materials Science and Engineering City University of Hong Kong Key Laboratory of Partial Acceleration Physics& Technology Institute of High Energy PhysicsChinese Academy of Sciences Department of Materials Science &Engineering Southern University of Science and Technology Department of Physics City University of Hong Kong State Key Laboratory of Silicon Materials Department of Materials Science and Engineering Zhejiang University

Solid solutions are ubiquitous in metals and alloys. Local chemical ordering(LCO) is a fundamental sub-nano/nanoscale process that occurs in many solid solutions and can be used as a microstructure to optimize strength and ductility. However, the formation of LCO has not been fully elucidated, let alone how to provide efficient routes for designing LCO to achieve synergistic effects on both superb strength and ductility. Herein, we propose the formation and control of LCO in negative enthalpy alloys. With engineering negative enthalpy in solid solutions, genetic LCO components are formed in negative enthalpy refractory high-entropy alloys(RHEAs). In contrast to conventional ‘trial-and-error' approaches, the control of LCO by using engineering negative enthalpy in RHEAs is instructive and results in superior strength(1160 MPa) and uniform ductility(24.5%) under tension at ambient temperature, which are among the best reported so far. LCO can promote dislocation cross-slip, enhancing the interaction between dislocations and their accumulation at large tensile strains; sustainable strain hardening can thereby be attained to ensure high ductility of the alloy. This work paves the way for new research fields on negative enthalpy solid solutions and alloys for the synergy of strength and ductility as well as new functions.

关键词： negative enthalpy alloys local chemical ordering strength ductility dislocation

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