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Transformation and mechanisms of climate wet/dry change on the northern Tibetan Plateau under global warming:A perspective from paleoclimatology

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Science China Earth Sciences 2024年第6期67卷 1932-1951页

作者： Yu LI Zhansen ZHANG Xueru ZHOU Minjun GAO Junjie DUAN Yaxin XUE Hao SHANG Shiyu LIU key laboratory of Western China’s Environmental systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China

The northern Tibetan Plateau is a climatically sensitive zone influenced by monsoon and westerly *** summer,water vapor transport can reach Qinghai Lake and the eastern section of the Qilian Mountains;in winter,westerly winds mainly control the *** article compares the wet/dry changes in the region during the mid-Holocene(MH)warm period,the medieval climate anomaly(MCA),the current warm period(CWP),and the future warm period from the perspective of *** found that the MH warm period was mainly affected by the orbit-controlled East Asian summer monsoon,and the region showed warm and humid climate *** MCA was mainly controlled by solar radiation,and there was a warm and dry *** CWP and the future warm period are mainly controlled by the rise in temperature caused by the increase in greenhouse gases,and the climate is becoming more *** wet/dry patterns in the CWP and the future warm period in the next century on the northern Tibetan Plateau are similar to those in the *** warming will lead to the expansion of the westerly belt and a gradually humid *** future wet/dry changes will be more similar to the MH warm period.

关键词： Northern Tibetan Plateau Wet/dry change Warm period similarity Driving mechanism Future assessment

Prescribed Performance Tracking Control of Time-Delay Nonlinear systems With Output Constraints

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1557-1565页

作者： Jin-Xi Zhang Kai-Di Xu Qing-Guo Wang IEEE the State key laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyang 110819China Institute of Artificial Intelligence and Future Networks Beijing Normal UniversityZhuhai 519087 Guangdong key laboratory of Artificial Intelligence and multi-Modal Data Processing Beijing Normal University-Hong Kong Baptist University United International CollegeZhuhai 519087

The problem of prescribed performance tracking control for unknown time-delay nonlinear systems subject to output constraints is dealt with in this paper. In contrast with related works, only the most fundamental requirements, i.e., boundedness and the local Lipschitz condition, are assumed for the allowable time delays. Moreover, we focus on the case where the reference is unknown beforehand, which renders the standard prescribed performance control designs under output constraints infeasible. To conquer these challenges, a novel robust prescribed performance control approach is put forward in this ***, a reverse tuning function is skillfully constructed and automatically generates a performance envelop for the tracking error. In addition, a unified performance analysis framework based on proof by contradiction and the barrier function is established to reveal the inherent robustness of the control system against the time delays. It turns out that the system output tracks the reference with a preassigned settling time and good accuracy,without constraint violations. A comparative simulation on a two-stage chemical reactor is carried out to illustrate the above theoretical findings.

关键词： Nonlinear systems output constraints prescribed performance reference tracking time delays

Extremum seeking control for UAV close formation flight via improved pigeon-inspired optimization

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Science China(Technological Sciences) 2024年第2期67卷 435-448页

作者： YUAN GuangSong DUAN HaiBin State key laboratory of Virtual Reality Technology and systems School of Automation Science and Electrical EngineeringBeihang University(BUAA)Beijing 100083China

This paper proposes a comprehensive design scheme for the extremum seeking control(ESC)of the unmanned aerial vehicle(UAV)close formation *** proposed design scheme combines a Newton-Raphson method with an extended Kalman filter(EKF)to dynamically estimate the optimal position of the following UAV relative to the leading *** reflect the wake vortex effects reliably,the drag coefficient induced by the wake vortex is considered as a performance ***,the performance function is parameterized by the first-order and second-order terms of its Taylor series *** the excellent performance of nonlinear estimation,the EKF is used to estimate the gradient and the Hessian matrix of the parameterized performance *** output feedback of the proposed scheme is determined by iterative calculation of the Newton-Raphson *** with the traditional ESC and the classic ESC,the proposed design scheme avoids the slow continuous time integration of the *** allows a faster convergence of relative position ***,the proposed method can provide a smoother command during the seeking process as the second-order term of the performance function is taken into *** convergence analysis of the proposed design scheme is accomplished by showing that the output feedback is a supermartingale *** improve estimation performance of the EKF,a improved pigeon-inspired optimization(IPIO)is proposed to automatically tune the noise covariance *** Carlo simulations for a three-UAV close formation show that the proposed design scheme is robust to the initial position of the following UAV.

关键词： unmanned aerial vehicle close formation extremum seeking control Newton-Raphson method improved pigeon-inspired optimization

Advanced 3D ordered electrodes for PEMFC applications: From structural features and fabrication methods to the controllable design of catalyst layers

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Green Energy & Environment 2024年第9期9卷 1336-1365页

作者： Kaili Wang Tingting Zhou Zhen Cao Zhimin Yuan Hongyan He Maohong Fan Zaiyong Jiang School of Chemistry & Chemical Engineering and Environmental Engineering Weifang University Beijing key laboratory of Ionic Liquids Clean Process State Key Laboratory of Multiphase Complex Systems CAS Key Laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences College Engineering and Physical Sciences and School of Energy Resources University of Wyoming

The catalyst layers(CLs) electrode is the key component of the membrane electrode assembly(MEA) in proton exchange membrane fuel cells(PEMFCs). Conventional electrodes for PEMFCs are composed of carbon-supported, ionomer, and Pt nanoparticles, all immersed together and sprayed with a micron-level thickness of CLs. They have a performance trade-off where increasing the Pt loading leads to higher performance of abundant triple-phase boundary areas but increases the electrode cost. Major challenges must be overcome before realizing its wide commercialization. Literature research revealed that it is impossible to achieve performance and durability targets with only high-performance catalysts, so the controllable design of CLs architecture in MEAs for PEMFCs must now be the top priority to meet industry goals. From this perspective, a 3D ordered electrode circumvents this issue with a support-free architecture and ultrathin thickness while reducing noble metal Pt loadings. Herein, we discuss the motivation in-depth and summarize the necessary CLs structural features for designing ultralow Pt loading electrodes. Critical issues that remain in progress for 3D ordered CLs must be studied and characterized. Furthermore, approaches for 3D ordered CLs architecture electrode development, involving material design, structure optimization, preparation technology, and characterization techniques, are summarized and are expected to be next-generation CLs for PEMFCs. Finally, the review concludes with perspectives on possible research directions of CL architecture to address the significant challenges in the future.

关键词： PEMFC 3D ordered electrode Structural features Preparation technology Ultralow Pt loading

The hydrophobic cluster on the surface of protein is the key structural basis for the SDS-resistance of chondroitinase VhChlABC

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Marine Life Science & Technology 2024年第1期6卷 93-101页

作者： Juanjuan Su Hao Wu Chengying Yin Fengchao Zhang Feng Han Wengong Yu School of Medicine and Pharmacy Ocean University of ChinaQingdao 266003China laboratory for Marine Drugs and Bioproducts Qingdao Marine Science and Technology CenterQingdao 266237China key laboratory of Marine Drugs Ministry of EducationQingdao 266003China Shandong Provincial key laboratory of Glycoscience and Glycoengineering Qingdao 266003China

The application of chondroitinase requires consideration of the complex microenvironment of the *** previous research reported a marine-derived sodium dodecyl sulfate(SDS)-resistant chondroitinase *** study further investigated the mechanism of VhChlABC resistance to *** on the hydrophobic cluster on its strong hydrophilic surface,it was found that the reduction of hydrophobicity of surface residues Ala181,Met182,Met183,Ala184,Val185,and Ile305 significantly reduced the SDS resistance and *** dynamics(MD)simulation and molecular docking analysis showed that I305G had more conformational flexibility around residue 305 than wild type(WT),which was more conducive to SDS insertion and *** affinity of A181G,M182A,M183A,V185A and I305G to SDS was significantly higher than that of *** conclusion,the surface hydrophobic microenvironment composed of six residues was the structural basis for SDS *** feature could prevent the binding of SDS and the destruction of hydrophobic packaging by increasing the rigid conformation of protein and reducing the binding force of *** study provides a new idea for the rational design of SDS-resistant proteins and may further promote chondroitinase research in the targeted therapy of lung diseases under the pressure of pulmonary surfactant.

关键词： Hydrophobic cluster Protein surface SDS-resistance Chondroitinase

3D coarse-grained DPM simulation of the MIP reaction-regeneration loop

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Particuology 2024年第6期89卷 57-66页

作者： Yanhao Ye Shuai Zhang Ji Xu Wei Ge State key laboratory of Mesoscience and Engineering(formerly State key laboratory of multiphase Complex systems) Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China

The reactor-regenerator loop is the core facility of the maximizing iso-paraffin(MIP)*** the discrete particle method(DPM)simulation can provide detailed information at the particle scale,it has been unable to simulate such a complex loop system due to limitations of coarse-grained(CG)models,computing software,and *** this study,a newly proposed soft-shell CG-DPM model with a CG ratio of up to 800 is used to simulate a 3.5 Mt/a industrial-scale MIP reactor-regenerator *** solid fraction distribution obtained is found to agree well with in-situ *** properties including the distribution of solid fraction,gas and solid velocity,standard derivation of solid fraction with time,temporal distribution of the flow field,and particle residence time distribution are measured in the simulation,which are meaningful to better design and operate such systems in the future.

关键词： Discrete particle method Coarse-grain Maximizing iso-paraffins Full-loop Reaction-regeneration system

Rastall gravity:accretion disk image in the context of radiation fields and visual transformations compared to Reissner-Nordström black hole

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Chinese Physics C 2024年第4期48卷 174-182页

作者：黄宇翔郭森梁宇崔宇昊蒋青权林恺 School of Physics and Astronomy China West Normal UniversityNanchong 637000China Guangxi key laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China Hubei Subsurface multi-scale Imaging key laboratory Institute of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China

In this study,we investigated the astronomical implications of Rastall gravity,particularly its behavior amidst a radiation field compared to Reissner-Nordström(RN)black *** found a crucial correlation between the dynamics of the accretion disk and the parameters Q and Nr,which properly reflect the influence of spacetime metrics on the disk’s *** electric charge Q causes contraction in the disk’s orbit due to enhanced gravitational effects,while higher Nr values lead to outward expansion,influenced by the attributes of the radiation ***,the charged black holes surrounded by radiation fields exhibit distinct visual disparities from RN black *** decreases and expansion occurs within the innermost stable circular orbit of the accretion disk with rising Nr *** study also reveals the process by which the accretion disk transitions from a conventional disk-like structure to a hat-like form at different observation angles,with the redshift effect gradually ***,the results of the considered Rastall gravity radiation field are consistent with the constraints of the gravitational lensing of the host galaxy on Rastall gravity parameters,thereby enhancing the consistency between theoretical predictions and actual observations.

关键词： Rastall theory optical appearance thin accretion disk

Gate-field control of valley polarization in valleytronics

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Chinese Physics B 2024年第6期33卷 2-12页

作者：张婷婷韩依琳张闰午余智明 Institute of Physics Chinese Academy of SciencesBeijing 100190China key laboratory of Advanced Optoelectronic Quantum Architecture and Measurement Beijing Key Laboratory of Nanophotonics&Ultrafine Optoelectronic Systemsand School of PhysicsBeijing Institute of TechnologyBeijing 100081China

Valleytronics materials are a kind of special semiconductors which can host multiple symmetry-connected and wellseparated electron or hole pockets in the Brillouin zone when the system is slightly n or p doped. Since the low-energy particles residing in these pockets generally are not easily scattered to each other by small perturbations, they are endowed with an additional valley degree of freedom. Analogous to spin, the valley freedom can be used to process information,leading to the concept of valleytronics. The prerequisite for valleytronics is the generation of valley polarization. Thus,a focus in this field is achieving the electric generation of valley polarization, especially the static generation by the gate electric field alone. In this work, we briefly review the latest progress in this research direction, focusing on the concepts of the couplings between valley and layer, i.e., the valley–layer coupling which permits the gate-field control of the valley polarization, the couplings between valley, layer, and spin in magnetic systems, the physical properties, the novel designing schemes for electronic devices, and the material realizations of the gate-controlled valleytronics materials.

关键词： band structure electronic transport optical properties spintronics

The ubiquitin codes in cellular stress responses

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Protein & cell 2024年第3期15卷 157-190页

作者： Xiangpeng Sheng Zhixiong Xia Hanting Yang Ronggui Hu key laboratory of systems Health Science of Zhejiang Province School of Life ScienceHangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China State key laboratory of Molecular Biology Shanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceChinese Academy of SciencesShanghai 200031China State key laboratory of Animal Disease Control Harbin Veterinary Research InstituteChinese Academy of Agricultural SciencesHarbin 150069China Department of Neurology State Key Laboratory of Medical NeurobiologyInstitute for Translational Brain ResearchMOE Frontiers Center for Brain ScienceZhongshan HospitalFudan UniversityShanghai 200032China

Ubiquitination/ubiquitylation,one of the most fundamental post-translational modifications,regulates almost every critical cellular process in *** evidence has shown that essential components of numerous biological processes undergo ubiquitination in mammalian cells upon exposure to diverse stresses,from exogenous factors to cellular reactions,causing a dazzling variety of functional *** forms of ubiquitin sig-nals generated by ubiquitylation events in specific milieus,known as ubiquitin codes,constitute an intrinsic part of myriad cellular stress *** ubiquitination events,leading to proteolytic turnover of the substrates or just switch in functionality,initiate,regulate,or supervise multiple cellular stress-associated responses,supporting adaptation,homeostasis recovery,and survival of the stressed *** this review,we attempted to summarize the crucial roles of ubiquitination in response to different environmental and intracellular stresses,while discussing how stresses modulate the ubiquitin *** review also updates the most recent advances in understanding ubiquitination machinery as well as different stress responses and discusses some important questions that may warrant future investigation.

关键词： ubiquitin E3 ligase environmental stresses intercellular stresses stress response homeostasis