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Effects of Environmental Factors on Corrosion Behavior of E690 Steel in Simulated Marine Environment

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 678-694页

作者： Jingjing Peng Jing Liu Shen zhang Zhihui Wang Xian zhang Kaiming wu Collaborative Innovation Center for Advanced Steels Hubei Province Key Laboratory of Systems Science in Metallurgical ProcessThe State Key Laboratory of Refractories and MetallurgyWuhan University of Science and TechnologyWuhan430081China

The effects of hydrostatic pressure, dissolved oxygen, temperature and flow velocity, and their interaction on the corrosion rates of E690 high-strength steel (HSS) in simulated marine environments were studied using response surface methodology. The results show that the flow velocity exerts the most significant influence on the corrosion rate of E690 HSS. Consequently, the corrosion behavior of E690 HSS under varying flow velocities were analyzed profoundly from initial pitting corrosion to long-term corrosion properties. The results indicate that the flow state facilitates the mass transfer and enhances the adsorption tendency of Cl− by enhancing the electrochemical activity of the steel surface. These factors accelerate the electrochemical reactions, resulting in increased pitting density, depth and the long-term corrosion rates in dynamic seawater environments.

关键词： E690 steel Simulated marine environment Corrosion behavior Flow velocity Response surface methodology(RSM)

Bioinspired Scraper-File Type Frequency-Doubling Ultrasonic Exciter

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Journal of Bionic Engineering 2024年第4期21卷 1801-1816页

作者： Wenshuai wu Mingshuo zhang Zeming Li Guang Yao Xinggang Jiang Deyuan zhang School of Mechanical Engineering and Automation Beihang UniversityBeijing100191China Institute of Bionic and Micro-Nano Systems Beihang UniversityBeijing100191China Guangdong Provincial Key Laboratory of Minimally Invasive Surgical Instruments and Manufacturing Technology Guangdong University of TechnologyGuangzhou510006China

In the natural world,leaf-cutting ants cause vibrations through their mutual scraping of file-scraper *** this study,we designed a Biomimetic Ultrasonic Exciter(BUE)that imitates leaf-cutting *** operating characteristics of the BUE were studied through experimental testing and finite element *** results showed that the BUE could generate stable ultrasonic vibrations,and that the excitation frequency only needed to be half the Output Frequency(OF).This frequency-doubling phenomenon was conducive to achieving BUE *** further explore the phenomenon of frequency-doubling vibration output,this study designed scrapers of five different sizes,conducted excitation and first-order natural frequency measurement tests,and the corresponding finite element *** was found that each scraper could operate in frequency-doubling mode,but the operating frequency and natural mode frequencies did not correspond with one *** further explicate experimental and simulation results,a two-degrees-of-freedom vibration model was *** was evident that the contact relationship between the dentate disc and scraper introduced strong nonlinear factors into the system,accounting for the frequency-doubling phenomenon and the difference between the BUE’s operating and mode *** BUE could be expected to facilitate the production of high-power micro-ultrasonic generators and has potential application value in the fields of mechanical processing,industrial production,and medical health.

关键词： Leaf-cutting ants Power ultrasound Nonlinear vibration Ultrasonic scalpel Micro vibrator

Synthesis and Modulation of Low-Dimensional Transition Metal Chalcogenide Materials via Atomic Substitution

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Nano-Micro Letters 2024年第9期16卷 49-94页

作者： Xuan Wang Akang Chen XinLei wu Jiatao zhang Jichen Dong Leining zhang Key Laboratory of Cluster Science Ministry of Education of ChinaBeijing Key Laboratory of Photoelectronic and Electrophonic Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 100081People’s Republic of China Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic SolidsInstitute of Chemistry Chinese Academy of SciencesBeijing 100190People’s Republic of China

In recent years,low-dimensional transition metal chalcogenide(TMC)materials have garnered growing research attention due to their superior electronic,optical,and catalytic properties compared to their bulk *** controllable synthesis and manipulation of these materials are crucial for tailoring their properties and unlocking their full potential in various *** this context,the atomic substitution method has emerged as a favorable *** involves the replacement of specific atoms within TMC structures with other elements and possesses the capability to regulate the compositions finely,crystal structures,and inherent properties of the resulting *** this review,we present a comprehensive overview on various strategies of atomic substitution employed in the synthesis of zero-dimensional,one-dimensional and two-dimensional TMC *** effects of substituting elements,substitution ratios,and substitution positions on the structures and morphologies of resulting material are *** enhanced electrocatalytic performance and photovoltaic properties of the obtained materials are also provided,emphasizing the role of atomic substitution in achieving these ***,challenges and future prospects in the field of atomic substitution for fabricating low-dimensional TMC materials are summarized.

关键词： Transition metal chalcogenides Atomic substitution Ion exchange Low-dimensional materials Controllable synthesis

Single Fe atom-anchored manganese dioxide for efficient removal of volatile organic compounds in refrigerator

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Nano Research 2024年第5期17卷 3927-3933页

作者： Yiwen Wang Jun zhang Yongfei zhang Yu zhang Zhe Wang Jing Wang Yuen wu Department of Endocrinology the First Affiliated Hospital of USTCDivision of Life Science and MedicineUniversity of Science and Technology of ChinaHefei 230001China School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026China Hefei Hualing Co. LtdHefei 230088China Linkway Technology Co. LtdResearch Institute of Single Atom Catalysts Industry TechnologyNanning 530000China

The efficient and rapid removal of volatile organic compounds(VOCs)holds significant importance for ensuring food quality and human health,particularly within the low-temperature confined spaces in ***,achieving effective VOCs degradation under such conditions poses challenges in terms of activating inert bonds and facilitating mass *** this study,we propose a novel solution by designing a cleaner module that incorporates 1.07%single Fe atom-anchored manganese dioxide catalysts(FeSAs-MnO_(2)).The combination of single Fe atoms and defect-rich MnO_(2) substrate efficiently activates molecular oxygen,leading to enhanced generation of highly reactive oxygen species(ROS).Non-thermal plasma(NTP)and circulating fan are introduced to facilitate the regeneration of catalytic activity and improve mass *** FeSAs-MnO_(2) cleaner module demonstrates exceptional performance in trimethylamine(TMA)removal,achieving a conversion efficiency of 98.9%for 9 ppm within just 9 ***,accelerated aging tests predict an extended service life of up to 45 years for the FeSAs-MnO_(2) cleaner module,surpassing the expected lifespan of refrigerators significantly.

关键词： single atom catalysts volatile organic compounds(VOCs) trimethylamine(TMA) non-thermal plasma(NTP) refrigerator

Mesoporous molecular sieve confined phase change materials with high absorption,enhanced thermal conductivity,and cooling energy charging/discharging capacity

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Frontiers of Materials Science 2024年第1期18卷 1-14页

作者： Qi zhang Chongyang Liu Xuehong wu Xueling zhang Jun Song School of Energy and Power Engineering Zhengzhou University of Light IndustryZhengzhou 450007China

The biggest challenge for organic phase change materials(PCMs)used in cold energy storage is to maintain high heat storage capacity while reducing the leakage risk of PCMs during the phase transition *** is crucial for expanding their applications in the more demanding cold storage *** this study,novel formstable low-temperature composite PCMs are prepared with mesoporous materials,namely SBA-15 and CMK-3(which are prepared using the template method),as supporting matrices and dodecane as the *** to the combined effects of capillary forces within mesoporous materials and interactions among dodecane molecules,both dodecane/SBA-15 and dodecane/CMK-3 exhibit outstanding shape stability and thermal cycling stability even after 200 heating/cooling *** comparison to those of dodecane/SBA-15,dodecane/CMK-3 exhibits superior cold storage performance and higher thermal ***,the phase transition temperature of dodecane/CMK-3 is-8.81℃ with a latent heat of 122.4 J·g^(-1).Additionally,it has a thermal conductivity of 1.21 W·m^(-1)·K^(-1),which is 9.45 times that of dodecane *** these highlight its significant potential for applications in the area of cold energy storage.

关键词： cold energy storage phase change material mesoporous molecular sieve CMK-3 SBA-15 cooling energy charging/discharging capacity

Metformin alleviates spinal cord injury by inhibiting nerve cell ferroptosis through upregulation of heme oxygenase-1 expression

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Neural Regeneration Research 2024年第9期19卷 2041-2049页

作者： Zhihua Wang wu Zhou Zhixiong zhang Lulu zhang Meihua Li Department of Neurosurgery The First Affiliated Hospital of Nanchang UniversityNanchangJiangxi ProvinceChina Postdoctoral Innovation Practice Base The First Affiliated Hospital of Nanchang UniversityNanchangJiangxi ProvinceChina Department of Nephrology Nanchang People’s Hospital Affiliated to Nanchang Medical CollegeNanchangJiangxi ProvinceChina

Previous studies have reported upregulation of heme oxygenase-1 in different central nervous system injury *** oxygenase-1 plays a critical anti-inflammatory role and is essential for regulating cellular redox *** is a classic drug used to treat type 2 diabetes that can inhibit *** studies have shown that,when used to treat cardiovascular and digestive system diseases,metformin can also upregulate heme oxygenase-1 ***,we hypothesized that heme oxygenase-1 plays a significant role in mediating the beneficial effects of metformin on neuronal ferroptosis after spinal cord *** test this,we first performed a bioinformatics analysis based on the GEO database and found that heme oxygenase-1 was upregulated in the lesion of rats with spinal cord ***,we confirmed this finding in a rat model of T9 spinal cord compression injury that exhibited spinal cord nerve cell *** intraperitoneal injection of metformin for 14 days was found to both upregulate heme oxygenase-1 expression and reduce neuronal ferroptosis in rats with spinal cord ***,we used a lentivirus vector to knock down heme oxygenase-1 expression in the spinal cord,and found that this significantly reduced the effect of metformin on ferroptosis after spinal cord *** together,these findings suggest that metformin inhibits neuronal ferroptosis after spinal cord injury,and that this effect is partially dependent on upregulation of heme oxygenase-1.

关键词： acyl-CoA synthetase long-chain family member 4 ferroptosis glutathione peroxidase 4 heme oxygenase-1 inflammation iron lipid peroxidation metformin neuroprotection spinal cord injury

Scene 3-D Reconstruction System in Scattering Medium

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Computers, Materials & Continua 2024年第8期80卷 3405-3420页

作者： Zhuoyifan zhang Lu zhang LiangWang Haoming wu School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing100876China School of Information and Communication Engineering Hainan UniversityHaikou570228China School of Computer Science and Technology Hainan UniversityHaikou570228China

Research on neural radiance fields for novel view synthesis has experienced explosive growth with the development of new models and *** NeRF(Neural Radiance Fields)algorithm,suitable for underwater scenes or scattering media,is also *** underwater 3D reconstruction systems still face challenges such as long training times and low rendering *** paper proposes an improved underwater 3D reconstruction system to achieve rapid and high-quality 3D ***,we enhance underwater videos captured by a monocular camera to correct the image quality degradation caused by the physical properties of the water medium and ensure consistency in enhancement across ***,we perform keyframe selection to optimize resource usage and reduce the impact of dynamic objects on the reconstruction *** pose estimation using COLMAP,the selected keyframes undergo 3D reconstruction using neural radiance fields(NeRF)based on multi-resolution hash encoding for model construction and *** terms of image enhancement,our method has been optimized in certain scenarios,demonstrating effectiveness in image enhancement and better continuity between consecutive frames of the same *** terms of 3D reconstruction,our method achieved a peak signal-to-noise ratio(PSNR)of 18.40 dB and a structural similarity(SSIM)of 0.6677,indicating a good balance between operational efficiency and reconstruction quality.

关键词： Underwater scene reconstruction image enhancement NeRF

Structure of the mantle transition zone in the central and western parts of the North China Craton using the receiver function 3D Kirchhoff migration method

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Science China Earth Sciences 2024年第9期67卷 2783-2795页

作者： Min ZHU Qingju wu Jieyuan NING Ruiqing zhang Institute of Geophysics China Earthquake AdministrationBeijing 100081China Institute of Theoretical and Applied Geophysics Peking UniversityBeijing 100871China

Using data from the regional broadband dense temporary array deployed by the ChinArray project,we applied the three-dimensional(3D)Kirchhoff migration method of the teleseismic P-wave receiver function to investigate discontinuity structures of the mantle transition zone(MTZ)in the central and western parts of the North China Craton(NCC)using a highresolution 3D velocity model of the East Asian *** results show that the 410-km discontinuity beneath the Datong Volcano is depressed by~10 km,indicating the presence of a high-temperature anomaly near the depth of 410 km,which is likely related to small-scale mantle upwelling caused by the dehydration of the stagnant Pacific Plate in the *** upwelling of hot material provides a heat source for surface magmatic *** the Bohai Bay Basin,significant subsidence of the 660-km discontinuity is observed,and the transition zone here is extensively ***’s suggested that the anomalies in this region are related to the stagnation of the Pacific slab in the *** the thickness of the transition zone west of the North-South Gravity Lineament appears normal,we propose that the subducting front of the Pacific slab did not cross the gravity lineament in the *** comparison,the small-scale subsidence of the 660-km discontinuity and the thickening of the MTZ observed north of the Hannuoba Volcano likely indicate that the slab crossed the gravity lineament at its turning point and remained in the ***,a local thickening of the MTZ is observed in the Dabie orogenic belt of the Qinling *** is believed to be a combined effect of lithospheric delamination into the transition zone in the lower Yangtze region and the stagnation of the Pacific Plate.

关键词： North China Craton Mantle transition zone Receiver function migration Datong Volcano

Size-Dependent Analysis of Piezoelectric–Elastic Bilayer Microbeams Based on General Strain Gradient Theory

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Acta Mechanica Solida Sinica 2024年第4期37卷 622-633页

作者： Kanghui wu Shenjie Zhou Zhenjie zhang Juanjuan Li School of Mechanical Engineering Shandong UniversityJinan250061China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationShandong UniversityJinan250061China

The classical piezoelectric theory fails to capture the size-dependent electromechanical coupling behaviors of piezoelectric microstructures due to the lack of material length-scale *** study presents the constitutive relations of a piezoelectric material in terms of irreducible transversely isotropic tensors that include material length-scale *** these relations and the general strain gradient theory,a size-dependent bending model is proposed for a bilayer cantilever microbeam consisting of a transversely isotropic piezoelectric layer and an isotropic elastic *** solutions are provided for bilayer cantilever microbeams subjected to force load and voltage *** proposed model can be simplified to the model incorporating only partial strain gradient *** study examines the effect of strain gradient by comparing the normalized electric potentials and deflections of different *** results show that the proposed model effectively captures size effects in piezoelectric microbeams,whereas simplified models underestimate size effects due to ignoring partial strain gradient effects.

关键词： Size dependency Piezoelectric microbeam Size effect Strain gradient effect