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Impact vibration properties of locally resonant fluid-conveying pipes

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Chinese Physics B 2020年第12期29卷 313-321页

作者： Bing Hu Fu-Lei Zhu Dian-Long Yu Jiang-Wei Liu zhen-fang zhang Jie Zhong Ji-Hong Wen Laboratory of Science and Technology on Integrated Logistics Support National University of Defense TechnologyChangsha 410073China

Fluid-conveying pipe systems are widely used in various equipments to transport matter and *** to the fluid–structure interaction effect,the fluid acting on the pipe wall is easy to produce strong vibration and noise,which have a serious influence on the safety and concealment of the *** on the theory of phononic crystals,this paper studies the vibration transfer properties of a locally resonant(LR)pipe under the condition of fluid–structure *** band structure and the vibration transfer properties of a finite periodic pipe are obtained by the transfer matrix ***,the different impact excitation and fluid–structure interaction effect on the frequency range of vibration attenuation properties of the LR pipe are mainly considered and calculated by the finite element *** results show that the existence of a low-frequency vibration bandgap in the LR pipe can effectively suppress the vibration propagation under external impact and fluid impact excitation,and the vibration reduction frequency range is near the bandgap under the fluid–structure interaction ***,the pipe impact experiment was performed to verify the effective attenuation of the LR structure to the impact excitation,and to validate the finite element *** research results provide a technical reference for the vibration control of the fluid-conveying pipe systems that need to consider blast load and fluid impact.

关键词： locally resonant pipe fluid-structure interaction transfer matrix method impact vibration properties

Propagation of acoustic waves in a fluid-filled pipe with periodic elastic Helmholtz resonators

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Chinese Physics B 2018年第6期27卷 285-291页

作者： Dian-Long Yu Hui-Jie Shen Jiang-Wei Liu Jian-Fei Yin zhen-fang zhang and Ji-Hong Wen Support National University of Defense Technology Changsha 410073 China College of Power Engineering Naval University of Engineering Wnhan 430033 China

Helmholtz resonators are widely used to reduce noise in a fluid-filled pipe system. It is a challenge to obtain lowfrequency and broadband attenuation with a small sized cavity. In this paper, the propagation of acoustic waves in a fluid-filled pipe system with periodic elastic Helmholtz resonators is studied theoretically. The resonance frequency and sound transmission loss of one unit are analyzed to validate the correctness of simplified acoustic impedance. The band structure of infinite periodic cells and sound transmission loss of finite periodic cells are calculated by the transfer matrix method and finite element software. The effects of several parameters on band gap and sound transmission loss are ***, the negative bulk modulus of periodic cells with elastic Helmholtz resonators is analyzed. Numerical results show that the acoustic propagation properties in the periodic pipe, such as low frequency, broadband sound transmission, can be improved.

关键词： acoustic metamaterial band gap sound transmission loss elastic Helmholtz resonator noise control

Optimizing electronic structure through point defect engineering for enhanced electrocatalytic energy conversion

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Green Energy & Environment 2025年第1期10卷 109-131页

作者： Wei Ma Jiahao Yao fang Xie Xinqi Wang Hao Wan Xiangjian Shen Lili zhang Menggai Jiao zhen Zhou Interdisciplinary Research Center for Sustainable Energy Science and Engineering(IRC4SE2) School of Chemical EngineeringZhengzhou UniversityHenan450001China

Point defect engineering endows catalysts with novel physical and chemical properties,elevating their electrocatalytic *** introduction of defects emerges as a promising strategy,effectively modifying the electronic structure of active *** optimization influences the adsorption energy of intermediates,thereby mitigating reaction energy barriers,altering paths,enhancing selectivity,and ultimately improving the catalytic efficiency of *** elucidate the impact of defects on the electrocatalytic process,we comprehensively outline the roles of various point defects,their synthetic methodologies,and characterization ***,we consolidate insights into the relationship between point defects and catalytic activity for hydrogen/oxygen evolution and CO_(2)/O_(2)/N_(2) reduction reactions by integrating mechanisms from diverse *** underscores the pivotal role of point defects in enhancing catalytic *** last,the principal challenges and prospects associated with point defects in current electrocatalysts are proposed,emphasizing their role in advancing the efficiency of electrochemical energy storage and conversion materials.

关键词： Point defect engineering Doping Vacancy Electrocatalysis Electronic structure

Prediction and optimization of flue pressure in sintering process based on SHAP

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 346-359页

作者： Mingyu Wang Jue Tang Mansheng Chu Quan Shi zhen zhang School of Metallurgy Northeastern UniversityShenyang 110819China Liaoning Low-Carbon Steelmaking Technology Engineering Research Center Northeastern UniversityShenyang 110819China Engineering Research Center of Frontier Technologies for Low-Carbon Steelmaking(Ministry of Education) Shenyang 110819China

Sinter is the core raw material for blast *** pressure,which is an important state parameter,affects sinter *** this paper,flue pressure prediction and optimization were studied based on the shapley additive explanation(SHAP)to predict the flue pressure and take targeted adjustment ***,the sintering process data were collected and processed.A flue pressure prediction model was then constructed after comparing different feature selection methods and model algorithms using SHAP+extremely random-ized trees(ET).The prediction accuracy of the model within the error range of±0.25 kPa was 92.63%.SHAP analysis was employed to improve the interpretability of the prediction *** effects of various sintering operation parameters on flue pressure,the relation-ship between the numerical range of key operation parameters and flue pressure,the effect of operation parameter combinations on flue pressure,and the prediction process of the flue pressure prediction model on a single sample were analyzed.A flue pressure optimization module was also constructed and analyzed when the prediction satisfied the judgment *** operating parameter combination was then *** flue pressure was increased by 5.87%during the verification process,achieving a good optimization effect.

关键词： sintering process flue pressure shapley additive explanation prediction optimization

Dual modulation of homogeneous nanomaterialization and electrochemical activation enhancing zinc ion storage

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Science China Chemistry 2025年第1期68卷 385-393页

作者： Jianwei Wang Huan Wang Kangning Wang Wenhui Wang Wenlin zhang Yanzhong zhen School of Chemistry & Chemical Engineering Yan'an University

Vanadium-based electrode materials are widely investigated,but the low specific capacity and slow electrochemical kinetics in aqueous zinc-ion batteries still limit their commercial ***,the VS2/Ca V4O9material with the morphology of nanoflower was synthesized by a one-step hydrothermal *** to the blocky structure of pure VS2material,the VS2/Ca V4O9material is composed of thinner homogeneous *** open structures could provide abundant electrochemical active sites and ion transport channels,and then promote the electrochemical reaction *** addition,they can also buffer the bulk strain during the reaction *** improve the utilization of vanadium elements,an in-situ electrochemical activation strategy is used to explore the storage performance of the VS2/Ca V4O9material,the different activation voltage range of 0.4–1.6 and 0.4–1.4 V are selected,*** with the longer activation plateau of activated-VS2,the VS2/Ca V4O9cathode could quickly reach the activation state in the range of 1.4–1.6 V and cause the release of additional Zn storage sites *** VS2/Ca V4O9cathode delivers a higher power density of 37,000 W kg-1and a significant energy density of 423 Wh *** the high current density of 15 A g-1,the VS2/Ca V4O9cathode still has a discharge capacity of 183.9m Ah g-1after 5,000 cycles,and the capacity decay rate per cycle is only 0.0042%.Continuous cyclic voltammetry （CV） curves,electrochemical impedance spectroscopy （EIS） measurements,density functional theory （DFT） calculation and galvanostatic intermittent titration technique （GITT） measurements demonstrate that the VS2/Ca V4O9cathode has a faster ion diffusion/charge transfer ***,the assembled flexible device has an excellent mechanical stability.

关键词： dual modulation homogeneous nanomaterialization electrochemical activation zinc ion storage

Observability for the Schr?dinger equation in a uniform magnetic field

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Acta Mathematica Sinica,English Series 2025年

作者： zhang fang Department of Mathematics Beijing Institute of Technology

We prove the observability inequalities at two time points for the Schr?dinger equation in a uniform magnetic field in dimensions 2 and 3. The proofs mainly rely on Nazarov’s uncertainty principle. In particular, the observability inequality in three dimensions can also be derived from the approach used to establish the Amerin-Berthier uncertainty principle.

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Isobaric enzymatic assays reveal depth-dependent variation in microbial ectoenzyme activities in the deepest ocean on Earth

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Science China Earth Sciences 2025年第1期68卷 185-194页

作者： Junwei CAO Jiahua WANG Hongge zhang Junhao DENG Binbin PAN Jiawang CHEN Li zhang Jiasong fang College of Oceanography and Ecological Science Shanghai Ocean University Ocean College Zhejiang University Laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and Technology

Microbial ectoenzymes play essential roles in the transformation and mineralization of organic matter in the ***, conventional methods for measuring microbial ectoenzyme activities(MEAs) in the deep ocean under atmospheric conditions can misrepresent the metabolic activities of indigenous microbial communities. To overcome this limitation, we measured the activities of three microbial ectoenzymes(aminopeptidase, α-glucosidase, and β-glucosidase) under both atmospheric and in situ pressure conditions in seawater collected using pressure-retaining and non-pressure-retaining samplers in the Challenger Deep, Mariana Trench. In the case of aminopeptidase and α-glucosidase, the highest isobaric MEAs were observed in the surface layer(50 m), followed by those at abyssopelagic depths(4,000–6,000 m) for aminopeptidase, hadal realm(10,903 m)for α-glucosidase, while β-glucosidase activity exhibited the highest value at 10,903 m. Furthermore, the isobaric MEAs in hadal waters were commonly found to be higher than the decompressed counterparts, highlighting the importance of pressure-retaining sampling and isobaric enzymatic assays. The half-saturation constant(Km) showed a general decreasing trend with depth,suggesting that the deep ocean microbes might have adapted to the high-pressure and oligotrophic environment by increasing their ectoenzyme's affinity to substrate. Furthermore, particle-free MEAs contribute more to the total MEAs in the deep ocean than particle-associated MEAs, suggesting the significance of cell-associated and dissolved ectoenzymes in ocean *** study provides a foundation for future investigations of MEAs in the ocean and has important implications for understanding the dynamics of microbially mediated biogeochemical cycling in marine ecosystems.

关键词： Pressure-retaining sampling Microbial ectoenzyme activity Deep-sea microbes High pressure Mariana Trench

Reconstruction characteristics of gut microbiota from patients with type 1 diabetes affect the phenotypic reproducibility of glucose metabolism in mice

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Science China Life Sciences 2025年第1期68卷 176-188页

作者： Zhiyi Wang Mengxue Gong Yuanyuan fang Huijuan Yuan Chenhong zhang State Key Laboratory of Microbial Metabolism School of Life Sciences and BiotechnologyShanghai Jiao Tong University Department of Endocrinology Henan Provincial People's HospitalPeople's Hospital of Zhengzhou University

The human microbiota-associated(HMA) mice model, especially the germ-free(GF)-humanized mice, has been widely used to probe the causal relationships between gut microbiota and human diseases such as type 1 diabetes(T1D). However, most studies have not clarified the extent to which the reconstruction of the human donor microbiota in recipient mice correlates with corresponding phenotypic reproducibility. In this study, we transplanted fecal microbiota from five patients with T1D and four healthy people into GF mice, and microbiota from each donor were transplanted into 10 mice. Mice with similar microbiota structure to the donor exhibited better phenotypic reproducibility. The characteristics of the microbial community assembly of donors also influenced the phenotypic reproducibility in mice, and individuals with a higher proportion of stochastic processes showed more severe disorders. Microbes enriched in patients with T1D had a stronger colonization potential in mice with impaired glucose metabolism, and microbiota functional features related to T1D were better reproduced in these mice. This indicates that assembly traits and colonization efficacy of microbiota influence phenotypic reproducibility in GF-humanized mice. Our findings provide important insights for using HMA mice models to explore links between gut microbiota and human diseases.

关键词： gut microbiome human microbiota-associated animal model type 1 diabetes

Wafer‑Scale Ag_(2)S‑Based Memristive Crossbar Arrays with Ultra‑Low Switching‑Energies Reaching Biological Synapses

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Nano-Micro Letters 2025年第3期17卷 328-339页

作者： Yuan Zhu Tomas Nyberg Leif Nyholm Daniel Primetzhofer Xun Shi zhen zhang Division of Solid‑State Electronics Department of Electrical EngineeringUppsala University75121 UppsalaSweden Department of Chemistry Uppsala UniversityUppsalaSweden Department of Physics and Astronomy Uppsala UniversityUppsalaSweden State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China

Memristive crossbar arrays(MCAs)offer parallel data storage and processing for energy-efficient neuromorphic ***,most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor(CMOS)technology still suffer from substantially larger energy consumption than biological synapses,due to the slow kinetics of forming conductive paths inside the memristive *** we report wafer-scale Ag_(2)S-based MCAs realized using CMOS-compatible processes at temperatures below 160℃.Ag_(2)S electrolytes supply highly mobile Ag+ions,and provide the Ag/Ag_(2)S interface with low silver nucleation barrier to form silver filaments at low energy *** further enhancing Ag+migration in Ag_(2)S electrolytes via microstructure modulation,the integrated memristors exhibit a record low threshold of approximately−0.1 V,and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological *** low-temperature process also enables MCA integration on polyimide substrates for applications in flexible ***,the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training *** impressive accuracy of 92.6%in image recognition simulations is demonstrated with the MCAs after the *** demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.

关键词： Wafer-scale Ag_(2)S films Reactive sputter Silver nucleation Ag^(+)migration Energy-efficient neuromorphic computing