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Bifurcation and Chaos Analysis of Nonlinear Rotor System with Axial-grooved Gas-lubricated Journal Bearing Support

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Chinese Journal of mechanical Engineering 2014年第2期27卷 358-368页

作者： ZHANG Yongfang HEI Di Lü Yanjun WANG Quandai müller norbert School of Printing and Packaging Engineering Xi'an University of Technology State Key Laboratory of mechanical Transmission Chongqing University College of Engineering Michigan State University School of mechanical and Precision Instrument Engineering Xi'an University of Technology Department of mechnical and Electrical Engineering Shaanxi Railway Institute

Axial-grooved gas-lubricated journal bearings have been widely applied to precision instrument due to their high accuracy, low friction, low noise and high stability. The rotor system with axial-grooved gas-lubricated journal bearing support is a typical nonlinear dynamic system. The nonlinear analysis measures have to be adopted to analyze the behaviors of the axial-grooved gas-lubricated journal bearing-rotor nonlinear system as the linear analysis measures fail. The bifurcation and chaos of nonlinear rotor system with three axial-grooved gas-lubricated journal bearing support are investigated by nonlinear dynamics theory. A time-dependent mathematical model is established to describe the pressure distribution in the axial-grooved compressible gas-lubricated journal bearing. The time-dependent compressible gas-lubricated Reynolds equation is solved by the differential transformation method. The gyroscopic effect of the rotor supported by gas-lubricated journal bearing with three axial grooves is taken into consideration in the model of the system, and the dynamic equation of motion is calculated by the modified Wilson-0-based method. To analyze the unbalanced responses of the rotor system supported by finite length gas-lubricated journal bearings, such as bifurcation and chaos, the bifurcation diagram, the orbit diagram, the Poincar6 map, the time series and the frequency spectrum are employed. The numerical results reveal that the nonlinear gas film forces have a significant influence on the stability of rotor system and there are the rich nonlinear phenomena, such as the periodic, period-doubling, quasi-periodic, period-4 and chaotic motion, and so on. The proposed models and numerical results can provide a theoretical direction to the design of axial-grooved gas-lubricated journal bearing-rotor system.

关键词： axial-grooved gas journal bearing differential transformation method nonlinear bifurcation chaos

轴向槽气体轴承—非线性转子系统的分岔和混沌

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机械工程学报 2014年第5期 210-211页

作者：张永芳吕延军黑棣王权岱 mller norbert 西安理工大学印刷包装工程学院重庆大学机械传动国家重点实验室密歇根州立大学工学院西安理工大学机械与精密仪器工程学院

轴向槽动压气体轴承具有高精度、低摩擦、低噪声和高稳定性的特点,广泛应用于精密仪器、医疗器械、飞机仪表舱等设备。由于轴向槽动压气体轴承支承的转子系统是典型的非线性动力系统,所以必须采用非线性分析的方法来研究系统的动力学行... 详细信息

轴向槽动压气体轴承具有高精度、低摩擦、低噪声和高稳定性的特点,广泛应用于精密仪器、医疗器械、飞机仪表舱等设备。由于轴向槽动压气体轴承支承的转子系统是典型的非线性动力系统,所以必须采用非线性分析的方法来研究系统的动力学行为。因此,运用非线性动力学理论研究三轴向槽动压气体轴承-转子系统的非线性行为。建立与时间相关的轴向槽可压缩气体润滑的压力分布模型,运用微分变换法求解可压缩气体润滑的Reynolds方程,得到轴向槽动压气体轴承的非线性气膜力。建立具有陀螺效应的转子系统模型,基于改进的Wilson-θ法求解系统动力学方程,得到系统的非线性不平衡响应。运用分岔图、轨迹图、Poincare映射、时间序列和频谱图分析不平衡响应的分岔和混沌。数值分析结果表明:非线性气膜力对转子系统的稳定性影响很大,系统展现出丰富的非线性行为,如周期解、倍周期解、拟周期解、周期四亚谐运动和混沌运动等。所做研究为工程中轴向槽动压气体轴承-转子系统的设计提供了理论指导。

关键词：轴向槽径向气体轴承微分变换法非线性分岔混沌

Development of an active-site titrant for SARS-CoV-2 main protease as an indispensable tool for evaluating enzyme kinetics

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Acta Pharmaceutica Sinica B 2024年第5期14卷 2349-2357页

作者： Rabea Voget Julian Breidenbach Tobias Claff Alexandra Hingst Katharina Sylvester Christian Steinebach Lan Phuong Vu Renato H.Weiße Ulrike Bartz norbert Sträter Christa E.müller michael Gütschow Pharmaceutical Institute Pharmaceutical&Medicinal ChemistryUniversity of BonnBonn 53121Germany Institute of Bioanalytical Chemistry Center for Biotechnology and BiomedicineLeipzig UniversityLeipzig 04103Germany Department of Natural Sciences University of Applied Sciences Bonn-Rhein-SiegRheinbach 53359Germany

A titrant for the SARS-CoV-2 main protease(m^(pro))was developed that enables,for the first time,the exact determination of the concentration of the enzymatically active m^(pro) by active-site *** covalent binding mode of the tetrapeptidic titrant was elucidated by the determination of the crystal structure of the enzyme–titrant *** fluorogenic substrates of m^(pro),including a prototypical,internally quenched Dabcyl-EDANS peptide,were compared in terms of solubility under typical assay *** exploiting the new titrant,key kinetic parameters for the m^(pro)-catalyzed cleavage of these substrates were determined.

关键词： COVID-19 SARS-CoV-2 main protease Peptide nitriles Fluorogenic substrates Active-site titration X-ray crystallography Inner filter effect

Boosting liver regeneration: kinase inhibitor as a new tool to prevent liver failure

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Signal Transduction and Targeted Therapy 2024年第8期9卷 3145-3146页

作者： Anna Sichler norbert Huser Klaus-Peter Janssen Department of Surgery School of Medicine and HealthTechnical University of MunichMunichGermany

In a recent manuscript in Cell,a first-in-class small molecule inhibitor of the kinase mKK4(mitogen-activated protein kinase kinase 4)was described that greatly enhances liver regeneration after partial hepatectomy in animal models,with an excellent safety profile in humans.1 The findings of Zwirner et *** promise to alter the clinical management of liver failure in critically ill patients.

关键词： liver al. clinical

Improving the hydrostability of zeolitic imidazolate framework coatings using a facile silk fibroin protein modification method

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Nano Research 2024年第7期17卷 6247-6257页

作者： Xiuming Wei Ting Chen Siyu Chen Qian Jia Nurul Ain mazlan Allana Lewis norbert Radacsi Yi Huang School of Engineering Institute for Materials&ProcessesThe University of EdinburghRobert Stevenson RoadEdinburghEH93FBUK EASTCHEm School of Chemistry The University of St AndrewsPurdie BuildingNorth HaughSt AndrewsKY169STUK

Zeolitic imidazolate frameworks(ZIFs)are an important subclass of metal-organic frameworks(mOFs)with zeolite-type topology,which can be fabricated under ambient synthesis ***,the applications of ZIFs are commonly limited due to the weak hydrostability of their metal–ligand coordination bonds,particularly under humid and aqueous *** this work,as an example,the hydrolysis behaviours of ZIF-L with a special focus on ZIF-L coatings were tested at aqueous conditions with a wide range of pHs to systematically study and fundamentally understand their structural stability and degradation *** ZIF-L powder and ZIF-L coatings were severely damaged after only 24 h in aqueous ***,the ZIF-L coatings showed two distinct hydrolyzation pathways regardless of pH conditions,exhibiting either a ring-shaped etching or unfolding *** the ZIF-L powders were hydrolyzed almost identically across all pH *** this new understanding,a facile silk fibroin(SF)protein modification method was developed to enhance the hydrostability of ZIF-L coatings in aqueous *** effect of protein concentration on surface coating was systemically ***-L coating retained its surface morphology after soaking in water and demonstrated switchable super wetting properties and superior separation performance for oil/water *** a result,the quick SF protein modification significantly enhanced the stability of ZIF-L coatings under various pHs,while retaining their switchable wetting property and excellent separation performance.

关键词： zeolitic imidazole framework-L(ZIF-L) ZIF-L coatings silk fibroin protein hydrostability enhancement oil/water separation

Insights into the kinetics–morphology relationship of 1-, 2-, and 3D TiNb_(2)O_(7) anodes for Li-ion storage

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Nano Research 2024年第4期17卷 2770-2780页

作者： Wenlei Xu Yaolin Xu Veronika Grzimek Andrea martin Thorsten Schultz Patrícia ARusso Yan Lu norbert Koch Nicola Pinna Department of Chemistry IRIS Adlershof and the Center for the Science of Materials BerlinHumboldt-Universität zu BerlinBrook-Taylor-Str.212489 BerlinGermany Department of Electrochemical Energy Storage Helmholtz-Zentrum Berlin für Materialien und EnergieHahn-Meitner-Platz 114109 BerlinGermany Institut für Physik and IRIS Adlershof Humboldt-Universität zu BerlinBrook-Taylor-Str.212489 BerlinGermany Joint Research Group of molecular Systems Helmholtz-Zentrum Berlin für Materialien und Energie12489 BerlinGermany

Understanding the influence of electrode material’s morphology on electrochemical behavior is of great significance for the development of rechargeable batteries,however,such studies are often limited by the inability to precisely control the morphology of electrode ***,nanostructured titanium niobium oxides(TiNb_(2)O_(7))with three different morphologies(one-dimensional(1D),two-dimensional(2D),and three-dimensional(3D))were synthesized via a facile microwave-assisted solvothermal *** influence of the morphological dimension of TiNb_(2)O_(7) as electrode material on the electrochemical performance in Li-ion batteries(LIBs)and the underlying correlation with the electrochemical kinetics were studied in detail.2D TiNb_(2)O_(7)(TNO-2D)shows a superior rate capability and cycling stability,associated with improved kinetics for charge transfer and Li-ion diffusion,compared to the 1D and 3D *** X-ray diffraction measurements reveal the structural stability and crystallographic evolution of TNO-2D upon lithiation and delithiation and correlate the Li-ion diffusion kinetics with the lattice evolution during battery charge and ***,carbon-coated TNO-2D achieves enhanced rate capability(205 mAh·g^(-1) at 50 C)and long-term cycling stability(87%after 1000 cycles at 5 C).This work provides insights into the rational morphology design of electrode materials for accelerated charge transfer and enhanced fast-charging capability,pushing forward the development of electrode materials for high-power rechargeable batteries in future energy storage.

关键词： morphological dimension electrochemical kinetics lithium-ion batteries TiNb_(2)O_(7) structural evolution

Using machine learning models to explore the solution space of large nonlinear systems underlying flowsheet simulations with constraints

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Frontiers of Chemical Science and Engineering 2022年第2期16卷 183-197页

作者： Patrick Otto Ludl Raoul Heese Johannes Höller norbert Asprion michael Bortz Fraunhofer ITWm Optimization Department Kaiserslautern 67663Germany Chemical and Process Engineering BASF SE Ludwigshafen 67056Germany

Flowsheet simulations of chemical processes on an industrial scale require the solution of large systems of nonlinear equations,so that solvability becomes a practical *** constraints from technical,economic,environmental,and safety considerations may further limit the feasible solution space beyond the convergence requirement.A priori,the design variable domains for which a simulation converges and fulfills the imposed constraints are usually unknown and it can become very time-consuming to distinguish feasible from infeasible design variable choices by simply running the simulation for each *** support the exploration of the design variable space for such scenarios,an adaptive sampling technique based on machine learning models has recently been ***,that approach only considers the exploration of the convergent domain and ignores additional *** this paper,we present an improvement which particularly takes the fulfillment of constraints into *** successfully apply the proposed algorithm to a toy example in up to 20 dimensions and to an industrially relevant flowsheet simulation.

关键词： machine learning flowsheet simulations constraints exploration

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冷知识：海水灭不了海底火山？！

环球人文地理 2024年第5期 108-109页

作者：怪罗先生 Jo norbert

2022年1月15日，南太平洋岛国汤加的洪阿哈阿帕伊岛海底火山爆发：从火山喷出的气体、烟雾和灰烬直冲天空，高达20公里，制造的巨大声波连远在北半球的美国都能听到，引发的海啸也让日本拉响了海啸预警……那些如世界末日来临般的场景...

2022年1月15日，南太平洋岛国汤加的洪阿哈阿帕伊岛海底火山爆发：从火山喷出的气体、烟雾和灰烬直冲天空，高达20公里，制造的巨大声波连远在北半球的美国都能听到，引发的海啸也让日本拉响了海啸预警……那些如世界末日来临般的场景，至今让许多人心有余悸。这是21世纪以来最强的一次火山喷发，喷发等级在5～6级之间，大概百年一遇。但人们也注意到，

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Decision support for the development,simulation and optimization of dynamic process models

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Frontiers of Chemical Science and Engineering 2022年第2期16卷 210-220页

作者： norbert Asprion Roger Böttcher Jan Schwientek Johannes Höller Patrick Schwartz Charlie Vanaret michael Bortz BASF SE 67063 LudwigshafenGermany Fraunhofer ITWm 67663 KaiserslauternGermany

Simulation is besides experimentation the major method for designing,analyzing and optimizing chemical *** ability of simulations to reflect real process behavior strongly depends on model *** and adaption of process models are usually based on available plant *** such a model in various simulation and optimization studies can support the process designer in his *** steady state models there is also a growing demand for dynamic models either to adapt faster to changing conditions or to reflect batch *** this contribution challenges of extending an existing decision support framework for steady state models to dynamic models will be discussed and the resulting opportunities will be demonstrated for distillation and reactor examples.

关键词： decision support multicriteria optimization model validation dynamic model sensitivity analysis