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Adaptive neural network control of a 2-DOF helicopter system considering input constraints and global prescribed performance

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Science china(Information Sciences) 2024年第7期67卷 224-239页

作者： Zhijia ZHAO Jiale wu Zhijie LIU We HE c.L.Philip cHEN School of Mechanical and Electrical Engineering Guangzhou University School of Intelligence Science and Technology and Key Laboratory of Intelligent Bionic Unmanned Systems of Ministry of Education University of Science and Technology Beijing School of computer Science and Engineering South China University of Technology Pazhou Lab

In this study, an adaptive neural network(NN) control is proposed for nonlinear two-degree-offreedom(2-DOF) helicopter systems considering the input constraints and global prescribed ***, radial basis function NN(RBFNN) is employed to estimate the unknown dynamics of the helicopter system. Second, a smooth nonaffine function is exploited to approximate and address nonlinear constraint functions. Subsequently, a new prescribed function is proposed, and an original constrained error is transformed into an equivalent unconstrained error using the error transformation and barrier function transformation methods. The analysis of the established Lyapunov function proves that the controlled system is globally uniformly bounded. Finally, the simulation and experimental results on a constructed Quanser's test platform verify the rationality and feasibility of the proposed control.

关键词： adaptive NN control 2-DOF helicopter global prescribed performance input constraints

Liquefaction susceptibility and deformation characteristics of saturated coral sandy soils subjected to cyclic loadings-a critical review

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 261-296页

作者： chen Guoxing Qin You Ma Weijia Liang Ke wu Qi c.Hsein Juang Institute of Geotechnical Engineering Nanjing Tech UniversityNanjing 210009China civil Engineering and Earthquake Disaster Prevention center of Jiangsu Province Nanjing 210009China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China college of civil Aviation Nanjing University of Aeronautics and AstronauticsNanjing 210016China Glenn Department of civil Engineering Clemson UniversityClemsonSC 29634USA

coral sandy soils widely exist in coral island reefs and seashores in tropical and subtropical *** to the unique marine depositional environment of coral sandy soils,the engineering characteristics and responses of these soils subjected to monotonic and cyclic loadings have been a subject of intense interest among the geotechnical and earthquake engineering *** paper critically reviews the progress of experimental investigations on the undrained behavior of coral sandy soils under monotonic and cyclic loadings over the last three *** focus of coverage includes the contractive-dilative behavior,the pattern of excess pore-water pressure(EPWP)generation and the liquefaction mechanism and liquefaction resistance,the small-strain shear modulus and strain-dependent shear modulus and damping,the cyclic softening feature,and the anisotropic characteristics of undrained responses of saturated coral sandy *** particular,the advances made in the past decades are reviewed from the following aspects:(1)the characterization of factors that impact the mechanism and patterns of EPWP build-up;(2)the identification of liquefaction triggering in terms of the apparent viscosity and the average flow coefficient;(3)the establishment of the invariable form of strain-based,stress-based,or energy-based EPWP ratio formulas and the unique relationship between the new proxy of liquefaction resistance and the number of cycles required to reach liquefaction;(4)the establishment of the invariable form of the predictive formulas of small strain modulus and strain-dependent shear modulus;and(5)the investigation on the effects of stress-induced anisotropy on liquefaction susceptibility and dynamic deformation *** gained through the critical review of these advances in the past decades offer a perspective for future research to further resolve the fundamental issues concerning the liquefaction mechanism and responses of coral sandy sites subjecte

关键词： liquefaction susceptibility dynamic deformation characteristics coral sandy soil cyclic loading review and prospect

Single-cell RNA sequencing facilitates the elucidation of the complete biosynthesis of the antidepressant hyperforin in St. John's wort

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Molecular Plant 2024年第9期17卷 1439-1457页

作者： Song wu Ana Luisa Malaco Morotti Jun Yang Ertao Wang Evangelos c.Tatsis National Key Laboratory of Plant Molecular Genetics CASs Center for Excellence in Molecular Plant SciencesShanghai lnstitute of Plant Physiology and EcologyChineseAcademy of SciencesShanghai 200032China University of chinese Academy of Sciences Shanghai 200032China UEPAMS-cAS-JIcs centre of Excellencefor Plant anamlcroblalSclence Snangnal 200032Cnina

Hyperforin is the compound responsible for the effectiveness of ***'s wort(Hypericum perforatum)as an antidepressant,but its complete biosynthetic pathway remains *** discovery based on co-expression analysis of bulk RNA-sequencing data or genome mining failed to discover the missing steps in hyperforin *** this study,we sequenced the 1.54-Gb tetraploid *** genome assem-bled into 32 chromosomes with the scaffold N50 value of 42.44 *** single-cell RNA sequencing,we iden-tified a type of cell,“Hyper cells”,wherein hyperforin biosynthesis de novo takes place in both the leaves and *** pathway reconstitution in yeast and tobacco,we identified and characterized four transmembrane prenyltransferases(HpPT1-4)that are localized at the plastid envelope and complete the hyperforin biosynthetic *** hyperforin polycyclic scaffold is created by a reaction cascade involving an irregular isoprenoid coupling and a tandem *** findings reveal how and where hy-perforin is biosynthesized,enabling synthetic-biology reconstitution of the complete ***,this study not only deepens our comprehension of specialized metabolism at the cellularlevel but also provides strategic guidance for elucidation of the biosynthetic pathways of other specializied metabolites in plants.

关键词： hyperforin Hypericum perforatum de novo genome sequencing single-cell RNA sequencing biosyn-thetic pathway meroterpenoids

Rational surface charge engineering of haloalkane dehalogenase for boosting the enzymatic performance in organic solvent solutions

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chinese Journal of chemical Engineering 2024年第1期65卷 276-285页

作者： Yin wu Yan Sun Department of Biochemical Engineering School of Chemical Engineering and Technology and Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education)Tianjin UniversityTianjin 300350China

Biocatalysis in organic solvents(OSs)has numerous important applications,but native enzymes in OSs often exhibit limited catalytic ***,we proposed a computation-aided surface charge engineering strategy to improve the catalytic performance of haloalkane dehalogenase DhaA in OSs based on the energetic analysis of substrate binding to the DhaA *** variants with enhanced OS resistance were obtained by replacing negative charged residues on the surface with positive charged residue(Arg).Particularly,a four-substitution variant E16R/E93R/E121R/E257R exhibited the best catalytic performance(five-fold improvement in OS resistance and seven-fold half-life increase in 40%(vol)dimethylsulfoxide).As a result,the overall catalytic performance of the variant could be at least 26 times higher than the wild-type *** spectroscopy and molecular dynamics simulation studies revealed that the residue substitution mainly enhanced OS resistance from four aspects:(a)improved the overall structural stability,(b)increased the hydrophobicity of the local microenvironment around the catalytic triad,(c)enriched the hydrophobic substrate around the enzyme molecule,and(d)lowered the contact frequency between OS molecules and the catalytic *** findings validate that computationaided surface charge engineering is an effective and ingenious rational strategy for tailoring enzyme performance in OSs.

关键词： Surface charge engineering Organic solvent resistance Molecular dynamics simulation Haloalkane dehalogenase

Review of Networked Microgrid Protection:Architectures,challenges,Solutions,and Future Trends

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cSEE Journal of Power and Energy Systems 2024年第2期10卷 448-467页

作者： Jorge de la cruz Ying wu John E.candelo-Becerra Juan c.Vasquez Josep M.Guerrero center for Research on Microgrids(cROM) Department of Energy TechnologyAalborg University9220 AalborgDenmark Facultad de Minas Departamento de Energia Eléctrica y AutomaticaUniversidad Nacional de ColombiaSede MedellinCarrera 80 No.65-223RobledoMedellin 050041Colombia. center for Research on Microgrids at UPc(UPc cROM) Department of Electronic EngineeringTechnical University of Catalonia(UPC)08019 Barcelona Spain IcREA Pg.Lluis Companys 2308010 BarcelonaSpain center for Research on Microgrids at AAU(AAU cROM) AAU EnergyAalborg University(AAU)9220 Aalborg EastDenmark

Design and selection of advanced protection schemes have become essential for reliable and secure operation of networked *** protection schemes that allow correct operation of microgrids have been proposed for individual systems in different topologies and ***,protection schemes for networked microgrids are still in devel-opment,and further research is required to design and operate advanced protection in interconnected *** of these microgrids in different nodes with various intercon-nection technologies increases fault occurrence and complicates protection *** paper aims to point out challenges in developing protection for networked microgrids,potential solutions,and research areas that need to be addressed for their ***,this article presents a systematic analysis of different microgrid clusters proposed since 2016,including several architectures of networked microgrids,operation modes,components,and utilization of renewable sources,which have not been widely explored in previous review ***,the paper presents a discussion on protection systems currently available for microgrid clusters,current challenges,and solutions that have been proposed for these ***,it discusses the trend of protection schemes in networked microgrids and presents some conclusions related to ***—Adaptive eprotection,microgrid cluster,microgrid,multiple microgrid,networked microgrid,real-time simulation,smart grid.

关键词： Adaptive eprotection microgrid cluster microgrid multiple microgrid networked microgrid real-time simulation smart grid

3D simulation of image-defined complex internal features using the numerical manifold method

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Science china(Technological Sciences) 2024年第4期67卷 1023-1039页

作者： wu Jie MA GuoWei School of civil and Transportation Engineering Hebei University of TechnologyTianjin 300401China Tianjin Key Laboratory for Prefabricated Building and Intelligent construction Tianjin 300401China

The numerical simulation of internal features,such as inclusions and voids,is important to analyze their impact on the performance of composite ***,the complex geometries of internal features and the induced continuous-discontinuous(c-D)deformation fields are challenges to their numerical *** this study,a 3D approach using a simple mesh to simulate irregular internal geometries is developed for the first *** the help of a developed voxel crack model,image models that are efficient when recording complex geometries are directly imported into the *** reconstructions,which are usually labor-intensive,are excluded from this ***,using image models as the geometric input,image processing techniques are applied to detect material interfaces and develop contact ***,the c-D deformations of the complex internal features are directly calculated based on the numerical manifold *** accuracy and convergence of the developed3D approach are examined based on multiple *** 3D c-D simulation of sandstones with naturally formed complex microfeatures demonstrates the capability of the developed approach.

关键词： 3D continuous-discontinuous simulation image-based simulation complex internal features numerical manifold method voxel crack model structured mesh

Efficient guiding and focusing of intense laser pulse using periodic thin slits

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Matter and Radiation at Extremes 2024年第4期9卷 29-39页

作者： L.Xu T.W.Huang K.Jiang c.N.wu H.Peng P.c.hen R.Li H.B.Zhuo c.T.Zhou Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology Center for Intense Laser ApplicationTechnologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118People’s Republic of China

Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle ***,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser *** fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing *** addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional *** results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.

关键词： laser pulse intense

cobalt doping amount determines dominant reactive species in peroxymonosulfate activation via porous carbon catalysts co-doped by cobalt and nitrogen

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Journal of Environmental Sciences 2024年第4期138卷 212-226页

作者： Xiang Li Limeng wu Aiqin Zhang Shaohua wu Yan Lin chunping Yang Key Laboratory of Jiangxi Province for Persistent Pollutants control and Resources Recycle Nanchang Hangkong UniversityNanchang 330063China Academy of Environmental and Resource Sciences School of Environmental Science and EngineeringGuangdong University of Petrochemical TechnologyMaoming 525000China college of Environmental Science and Engineering Hunan University and Key Laboratory of Environmental Biology and Pollution Control(Hunan University)Ministry of EducationChangsha 410082China

Switching the reaction routes in peroxymonosulfate(PMS)-based advanced oxidation processes have attracted much attention but remain ***,a series of co-N/c catalysts with different compositions and structures were prepared by using bimetallic zeolitic imidazolate frameworks based on ZIF-8 and ZIF-67(x Zn/co-ZIFs).Results show that co doping amount could mediate the transformation of the activation pathway of PMS over coN/*** co doping amount was less than 10%,the constructed x co-N/c/PMS system(x≤10%)was singlet oxygen-dominated reaction;however further increasing co doping amount would lead to the generation and coexistence of sulfate radicals and high-valent cobalt,besides singlet ***,the nitrogen-coordinated co(co-NX)sites could serve as main catalytically active sites to generate singlet *** excess co doping amount caused the formation of co nanoparticles from which leached co ions were responsible for the generation of sulfate radicals and high-valent *** to undoped N/c,co doping could significantly enhance the catalytic *** 0.5%co-N/c could achieve the optimum degradation(0.488 min^(-1))and mineralization abilities(78.4%)of sulfamethoxazole among the investigated co-N/c catalysts,which was superior to most of previously reported *** addition,the application prospects of the two systems in different environmental scenarios(pH,inorganic anions and natural organic matter)were assessed and showed different degradation *** study provides a strategy to regulate the reactive species in PMS-based advanced oxidation process.

关键词： Peroxymonosulfate Sulfate radical Singlet oxygen cobalt Zeolitic imidazolate framework Advanced oxidation process

Functionalized selenium nanoparticles ameliorated acetaminophen-induced hepatotoxicity through synergistically triggering PKcδ/Nrf2 signaling pathway and inhibiting cYP 2E1

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Food Science and Human Wellness 2024年第2期13卷 932-945页

作者： Si Zou Yetao Gong Xiujie Li Yanbin wu Jinzhong wu Jianguo wu Ka-Hing Wong college of Pharmacy Fujian University of Traditional Chinese MedicineFuzhou 350122China Research Institute for Future Food The Hong Kong Polytechnic UniversityHong Kong 999077China Department of Food Science and Nutrition The Hong Kong Polytechnic UniversityHong Kong 999077China

Selenium nanoparticles(SeNPs)have been demonstrated potential for use in diseases associated with oxidative *** SeNPs with lower toxicity and higher biocompatibility could bring better therapeutic activity and clinical application ***,this work was conducted to investigate the protective effect of Pleurotus tuber-regium polysaccharide-protein complex funtionnalized SeNPs(PTR-SeNPs)against acetaminophen(APAP)-induced oxidative injure in HepG2 cells and c57BL/6J mouse *** elucidation of the underlying molecular mechanism,in particular their modulation of Nrf2 signaling pathway was also *** results showed that PTR-SeNPs could significantly ameliorate APAP-induced oxidative injury as evidenced by a range of biochemical analysis,histopathological examination and immunoblotting ***-SeNPs could hosphorylate and activate PKcδ,depress Keap1,and increase nuclear accumulation of Nrf2,resulting in upregulation of GcLc,GcLM,HO-1 and NQO-1 ***,PTR-SeNPs suppressed the biotransformation of APAP to generate intracellular ROS through cYP 2E1 inhibition,restoring the mitochondrial ***,the protective effect of PTR-SeNPs against APAP induced hepatotoxicity was weakened as Nrf2 was depleted in vivo,indicating the pivotal role of Nrf2 signaling pathway in PTR-SeNPs mediated hepatoprotective *** a potential hepatic protectant,PTR-SeNPs could serve as a new source of selenium supplement for health-promoting and biomedical applications.

关键词： PTR-SeNPs(polysaccharide-proteincomplex functionalized selenium nanoparticles) Acetaminophen-induced hepatotoxicity Nuclear factor erythroid 2-related factor 2 cytochrome P450 enzyme 2E1 Mitochondria