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PEMFC Fractional-order Subspace Identification Model

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China Petroleum Processing & Petrochemical Technology 2022年第3期24卷 151-160页

作者： Sun Chengshuo qi zhidong qin Hao Shan Liang School of Automation Nanjing University of Science and TechnologyNanjing210094

A proton exchange membrane fuel cell(PEMFC)is a new type of hydrogen fuel cell that plays an indispensable role in an energy network.However,the multivariable and fractional-order characteristics of PEMFC make it difficult to establish a practical model.Herein,a fractional-order subspace identification model based on the adaptive monarch butterfly optimization algorithm with opposition-based learning(ALMBO)algorithm is proposed for PEMFC.Introducing the fractional-order theory into the subspace identification method by adopting a Poisson filter for with input and output data,a weight matrix is proposed to improve the identification accuracy.Additionally,the ALMBO algorithm is employed to optimize the parameters of the Poisson filter and fractional order,which introduces an opposition-based learning strategy into the migration operator and incorporates adaptive weights to improve the optimization accuracy and prevent falling into a locally optimal solution.Finally,the PEMFC fractional-order subspace identification model is established,which can accurately describe the dynamic process of PEMFC.

关键词： PEMFC fractional subspace identification weight matrix ALMBO

Discovery of a normal-tension glaucoma-suspect rhesus macaque with craniocerebral injury:Hints of elevated translaminar cribrosa pressure difference

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Chinese Medical Journal 2024年第4期137卷 484-486页

作者： Jian Wu qi Zhang Xu Jia Yingting Zhu zhidong Li Shu Tu Ling Zhao Yifan Du Wei Liu Jiaoyan Ren Liangzhi Xu Hanxiang Yu Fagao Luo Wenru Su Ningli Wang Yehong Zhuo State Key Laboratory of Ophthalmology Zhongshan Ophthalmic CenterGuangdong Provincial Key Laboratory of Ophthalmology and Visual ScienceSun Yat-sen UniversityGuangzhouGuangdong 510060China Beijing Institute of Ophthalmology Beijing Tongren Eye CenterBeijing Tongren HospitalCapital Medical UniversityBeijing Ophthalmology&Visual Sciences Key LaboratoryBeijing 100730China School of Food Sciences and Engineering South China University of TechnologyGuangzhouGuangdong 510641China Guangzhou Huazhen Biosciences GuangzhouGuangdong 510920China

To the Editor:Normal-tension glaucoma(NTG)is a progressive optic neuropathy characterized by irreversible blindness with statistically normal intraocular pressure(IOP)(≤21 mmHg),^([1,2])which makes early-stage diagnosis in the clinical practice difficult.Pathophysiological pathways underlying NTG include vascular dysregulation,toxic metabolite accumulation,and elevated translaminar cribrosa pressure difference(TLCPD).^([3])Although various small animal models have provided evidence of different pathophysiological mechanisms,the complicated clinical phenotype cannot be fully imitated by secondary disease models,and the gap between rodents and humans weakens their translational potential.Thus,the pathological changes associated with NTG remain unclear.

关键词： elevated glaucoma diagnosis

Taming heat with tiny pressure

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The Innovation 2024年第2期5卷 70-78页

作者： Kun Zhang Zhe Zhang Hailong Pan Haoyu Wang Xueting Zhao Ji qi Zhao Zhang Ruiqi Song Chenyang Yu Biaohong Huang Xujing Li Huaican Chen Wen Yin Changlong Tan Weijin Hu Michael Wüubbenhorst Jiangshui Luo Dehong Yu zhidong Zhang Bing Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Laboratory for Soft Matter and Biophysics Department of Physics and AstronomyKU Leuven3001 LeuvenBelgium Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China College of Materials Science and Engineering Sichuan UniversityChengdu 610064China School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150080China Australian Nuclear Science and Technology Organisation Lucas HeightsNSW 2234Australia

Heat is almost everywhere.Unlike electricity,which can be easily manipulated,the current ability to control heat is still highly limited owing to spontaneous thermal dissipation imposed by the second law of thermodynamics.Optical illumination and pressure have been used to switch endothermic/exothermic responses of materials via phase transitions;however,these strategies are less cost-effective and unscalable.Here,we spectroscopically demonstrate the glassy crystal state of 2-amino-2-methyl-1,3-propanediol(AMP)to realize an affordable,easily manageable approach for thermal energy recycling.The supercooled state of AMP is so sensitive to pressure that even several megapascals can induce crystallization to the ordered crystal,resulting in a substantial temperature increase of 48 K within 20 s.Furthermore,we demonstrate a proof-of-concept device capable of programable heating with an extremely high work-to-heat conversion effi-ciency of383.Such delicate and efficient tuning of heat may remarkably facilitate rational utilization of waste heat.

关键词： illumination thermal rational

Recent advances in multifunctional shape memory photonic crystals and practical applications

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Nano Research 2024年第1期17卷 79-96页

作者： Yong qi Shufen Zhang State Key Laboratory of Fine Chemicals Frontier Science Center for Smart MaterialsDalian University of TechnologyDalian 116024China

Shape memory photonic crystals(SMPCs)are smart composite materials with changeable structural color integrated by shape memory polymer and photonic crystals.SMPC can produce one or more temporary shapes through nanoscale deformation,memorizing current states.SMPC can be recovered to their original shapes or some intermediate states under external stimuli,accompanied by the variation of structural color.As porous carriers with built-in sensing properties,SMPCs promoted the interdisciplinary development of nanophotonic technology in materials science,environmental engineering,biomedicine,chemical engineering,and mechanics.Herein,the recent progress on multifunctional SMPCs and practical applications,including traditional and cold programmable SMPCs,is summarized and discussed.The primary concern is shape programming at the nanoscale that has demonstrated numerous attractive functions,including smart sensing,ink-free printing,solvent detection,reprogrammable gradient wetting,and controllable bubble transportation,under variations of the surface nanostructure.It aims to figure out the nanoscale shape memory effects on structural color conversion and additional performance,inspiring the fabrication of the next generation of SMPCs.Finally,perspectives on future research directions and applications are also presented.It is believed that multifunctional SMPCs are powerful nanophotonic tools for the interdisciplinary development of numerous disciplines in the future.

关键词： photonic crystal shape memory structural color cold programmable shape recovery

Geometric Constraints for Global Regularity of 3D Shear Thickening Fluids

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 205-210页

作者： Jia-qi Yang Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518063China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China

We consider the relation between the direction of the vorticity and the global regularity of 3D shear thickening fluids.It is showed that a weak solution to the non-Newtonian incompressible fluid in the whole space is... 详细信息

关键词： direction of the vorticity non-Newtonian fluid global regularity

Understanding the spatial interaction of ultrasounds based on three-dimensional dual-frequency ultrasonic field numerical simulation

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China Foundry 2024年第1期21卷 29-43页

作者： Zhao-yang Yin qi-chi Le Yan-chao Jiang Da-zhi Zhao qi-yu Liao qi Zou Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy melt.The effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in detail.Additionally,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct ultrasounds.As a result,various acoustic pressure distributions and cavitation regions are obtained.The spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical rods.Increasing the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution pattern.The acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).

关键词： dual-frequency ultrasonic numerical model acoustic pressure spatial interaction magnesium alloy

Adaptive sampling for corrugated plate digitization using a laser displacement sensor

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Science China(Technological Sciences) 2024年第5期67卷 1510-1523页

作者： WU ChengXing qi qi CHEN BaiJin YANG JiXiang DING Han State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

The surface quality of a corrugated plate directly determines the heat transfer property of the thermal power mechanical apparatus.Traditional detection methods are impractical for real-world production,being slow and destructive.In contrast,the point laser displacement sensor,employing the optical triangle method,emerges as a promising device for assessing parts with variable curvature and highly reflective surfaces.Despite its benefits,high-density sampling by an innate frequency introduces challenges such as data redundancy and a poor signal-to-noise ratio,potentially affecting the efficiency and precision of subsequent data processing.To address these challenges,adjustable frequency data sampling has been developed for this sensor,allowing adaptive sampling for corrugated plate digitization.The process begins with surface digitization to extract discrete points,which are transformed into intersection curves using the B-spline fitting technique.Subsequently,dominant points are identified,considering multigeometric constraints for curvature and arch height.Finally,the sampling signal is adjusted based on the distribution information of dominant points.Comparative results indicate that the proposed method effectively minimizes redundant sampling without compromising the accurate capture of essential geometric features.

关键词： corrugated plate laser displacement sensor adaptive sampling dominant point curvature arch height

A systematic COSMO-RS study on mutual solubility of ionic liquids and C6-hydrocarbons

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Green Chemical Engineering 2024年第1期5卷 97-107页

作者： Chuxin qi Zhen Song Hongye Cheng Lifang Chen Zhiwen qi State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and Technology130 Meilong RoadShanghai200237China

When considering the usage of ionic liquids(ILs)for reactions and separations involving non-polar or weak-polar hydrocarbons,the knowledge of the mutual solubility behaviors of ILs and hydrocarbons is of the utmost importance.In this work,taking four typical C6-hydrocarbons namely benzene,cyclohexene,cyclohexane,and hexane as representatives,the mutual solubility of ILs and non-polar or weak-polar hydrocarbons are systematically studied based on the COSMO-RS model.The reliability of COSMO-RS for these systems is first evaluated by comparing experimental and predicted hydrocarbon-in-IL activity coefficient at infinite dilution and binary/ternary liquid-liquid equilibria of related systems.Then,the mutual solubility of the four hydrocarbons and13,650 ILs(composed by 210 cations and 65 anions)are predicted.The effect of different IL structural characteristics including alkyl chain length,cation family/symmetry/functional group,and anion on the IL-hydrocarbon mutual solubility behaviors are further analyzed by the analyses of interaction energy and screen charge distribution.The mutual solubility databases and the structural effects identified thereon could provide useful guidance for IL selection in related applications.

关键词： C6-hydrocarbons Ionic liquids Mutual solubility COSMO-RS Structural effect analysis

Deciphering and integrating invariants for neural operator learning with various physical mechanisms

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National Science Review 2024年第4期11卷 111-122页

作者： Rui Zhang qi Meng Zhi-Ming Ma Academy of Mathematics and Systems Science Chinese Academy of Sciences(CAS) Microsoft Research

Neural operators have been explored as surrogate models for simulating physical systems to overcome the limitations of traditional partial differential equation(PDE) solvers. However, most existing operator learning methods assume that the data originate from a single physical mechanism, limiting their applicability and performance in more realistic scenarios. To this end, we propose the physical invariant attention neural operator(PIANO) to decipher and integrate the physical invariants for operator learning from the PDE series with various physical mechanisms. PIANO employs self-supervised learning to extract physical knowledge and attention mechanisms to integrate them into dynamic convolutional layers.Compared to existing techniques, PIANO can reduce the relative error by 13.6%–82.2% on PDE forecasting tasks across varying coefficients, forces or boundary conditions. Additionally, varied downstream tasks reveal that the PI embeddings deciphered by PIANO align well with the underlying invariants in the PDE systems, verifying the physical significance of PIANO.

关键词： neural operator PDE solver contrastive learning physical invariants