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Suppression of low-frequency ultrasound broadband vibration using star-shaped single-phase metamaterials

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Defence Technology（防务技术） 2024年第4期34卷 217-224页

作者： Rui Zhao Jian Zheng Jin Guo Yunbo Shi Hengzhen feng jun Tang jun liu Science and Technology on Electronic Test&Measurement Laboratory North University of ChinaTaiyuan 030051ShanxiChina School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties,which is configured by hybrid arc and sharp-angle convergent star-shaped *** effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and *** target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent *** proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity,and the simulation results verify a 99%vibration attenuation amplitude can be obtained in the frequency of20 k Hz—100 k *** the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique,the transmission loss experiments are performed,and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85%attenuation for the target *** results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation,which has capability for the vibration attenuation in the application of highprecise equipment.

关键词： Star-shaped metamaterials Broadband Vibration attenuation Low-frequency ultrasound vibration Transmission loss

Radical denitrogenative transformations of polynitrogen heterocycles:Building C–N bonds and beyond

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Chinese Journal of Catalysis 2021年第11期42卷 1865-1875页

作者： Wen-Chao Yang Cai-Yun Chen jun-feng li Zu-li Wang Institute of Pesticide School of Horticulture and Plant ProtectionYangzhou UniversityYangzhou 225009JiangsuChina Institute of Ensiling and Processing of Grass College of Agro-grassland ScienceNanjing Agricultural UniversityNanjing 210095JiangsuChina College of Chemistry and Pharmaceutical Sciences Qingdao Agricultural UniversityQingdao 266109ShandongChina

Polynitrogen heterocycles are readily available and have recently arisen as versatile synthons for the formation of various C-C and C-X bonds,and medicinally active nitrogen-containing *** cascade reactions,including annulation,radical cascade,and borylation reactions,have been reported in which polynitrogen heterocycles are applied as arylation *** success of these exceptional reactions illustrates the great synthetic potential of polynitrogen heterocycles,which provides a direct and useful approach to arylation reactions and the synthesis of nitrogen-containing *** use of photocatalysts to effectively transfer energy from visible light to non-absorbing compounds has gained increasing attention as this method allows for the mild and efficient generation of radicals in a controlled *** approach has thus led to new methods that involve unique bond formation *** addition,the use of free radical intermediates stabilized by transition metal catalysts is a powerful way to construct new chemical *** aim of this review is to highlight the rapidly expanding area of radical-initiated denitrogenative cascade reactions of polynitrogen heterocycles and elaborate on their mechanisms from a new perspective by using photocatalysis and metal-based catalysis.

关键词： Denitrogenation C-N bond Cyclization Polynitrogen heterocycles Radical

Synergistic integration of self-supported 1T/2H-WS_(2) and nitrogendoped rGO on carbon cloth for pH-universal electrocatalytic hydrogen evolution

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Nano Research 2024年第3期17卷 1267-1280页

作者： feng Ming Yap Jian Yiing Loh Wee-jun Ong School of Energy and Chemical Engineering Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia Center of Excellence for NaNo Energy&Catalysis Technology(CONNECT) Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Gulei Innovation Institute Xiamen UniversityZhangzhou 363200China Shenzhen Research Institute of Xiamen University Shenzhen 518057China

Hydrogen economy based on electrochemical water splitting exemplified one of the most promising means for overcoming the rapid consumption of fossil fuels and the serious deterioration of global *** development of earth-abundant,efficient,and durable electrocatalysts for hydrogen evolution reaction(HER)plays a vital role in the commercialization of water ***,the self-supported electrode with unique nitrogen-doped reduced graphene oxide(N-rGO)nanoflakes and WS_(2) hierarchical nanoflower that were grown directly on carbon cloth(CC)substrate(WS_(2)/N-rGO/CC)was successfully synthesized using a facile dual-step hydrothermal *** as-synthesized 50%1T/2H-WS_(2)/N-rGO/CC(WGC),which possessed high metallic 1T phase of 57%not only efficiently exposed more active sites and accelerated mass/charge diffusion,but also endowed excellent structural lustiness,robust stability,and durability at a high current *** a result,the 50%WGC exhibited lower overpotentials and Tafel slopes of 21.13 mV(29.55 mV∙dec^(-1))and 80.35 mV(137.02 mV∙dec^(-1))as compared to 20%Pt-C/CC,respectively for catalyzing acidic and alkaline hydrogen evolution ***,the as-synthesized 50%WGC also depicted long-term stability for more than 8 h in the high-current-density regions(100 and 220 mA∙cm^(-2)).In brief,this work reveals a self-supported electrode as an extraordinary alternative to Pt-based catalysts for HER in a wide pH range,while paving a facile strategy to develop advanced electrocatalysts with abundant heterointerfaces for practical applications in energy-saving hydrogen production.

关键词： self-supported electrocatalyst carbon-based substrate phase engineering pH-universal water splitting

New insights into the deposition of natural gas hydrate on pipeline surfaces:A molecular dynamics simulation study

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Petroleum Science 2024年第1期21卷 694-704页

作者： jun Zhang Hai-Qiang Fu Mu-Zhi Guo Zhao Wang li-Wen li Qi Yin You-Guo Yan Wei Wei Wei-feng Han Jie Zhong School of Materials Science and Engineering China University of Petroleum(East China)Qingdao 266580ShandongChina School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580ShandongChina Department of Alternative Energy PetroChina Research Institute of Petroleum Exploration&DevelopmentLangfang 065007HebeiChina

Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low *** hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH *** studies suggested the water film can greatly increase hydrate adhesion in gas-dominant ***,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion ***,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film *** water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate *** absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Feliquid layer,the process of which becomes harder as liquid layer *** a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant ***,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces.

关键词： Deposition Natural gas hydrate Pipelines Water affinity Adhesion strength

Tumor microenvironment-responsive arsenic-loaded layered double hydroxides film with synergistic anticancer and bactericidal activity

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Rare Metals 2024年第3期43卷 1207-1221页

作者： Shun Xing Dong-Hui Wang Hai-feng Zhang li-Dan liu Cheng-Ce li Chao Wei jun-Yu liu Nai-Jian Ge Xuan-Yong liu State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049China Intervention Center Eastern Hepatobiliary Surgery HospitalThe Third Affiliated Hospital of Naval Medical UniversityShanghai200438China School of Health Sciences and Biomedical Engineering Hebei University of TechnologyTianjin300130China

Malignant obstruction makes gallbladder cancer have a high mortality ***-titanium alloy(nitinol)stents are commonly used as a local intervention to maximize patient survival time,but the stents lack antitumor and antibacterial capacity and are vulnerable to secondary ***-based drugs show good therapeutic promise against gallbladder *** meet clinical *** layered double hydroxides(LDHs)film is constructed on the nitinol,whose arsenite loading amounts rose by 60%after simple heat treatment compared with the conventional anion-exchange *** addition,calcination promotes the dissolution of nickel ions from the LDHs lattice,resulting in a powerful synergistic killing effect on tumor cells together with the released *** importantly,the calcined arsenic-loaded LDHs are sensitive to the acidic microenvironment of tumor tissues,which presents a much lower arsenic and nickel release amount in the normal tissues,guaranteeing its ***,the vertically sharp LDHs nanosheets can synergize with arsenic to achieve effective physical cleavage and chemical killing of adherent and planktonic *** short,we attempt to use arsenic drugs for local interventions and reasonably avoid their toxic side effects,which provides a new design idea for nitinol stents applied in the treatment of gallbladder cancer.

关键词： Nitinol Layered double hydroxides Arsenic Gallbladder cancer

A Deep Model for Partial Multi-label Image Classification with Curriculum-based Disambiguation

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Machine Intelligence Research 2024年第4期21卷 801-814页

作者： feng Sun Ming-Kun Xie Sheng-jun Huang MIIT Key Laboratory of Pattern Analysis and Machine Intelligence College of Computer Science and TechnologyNanjing University of AeronauticsandAstronauticsNanjing211106China

In this paper,we study the partial multi-label(PML)image classification problem,where each image is annotated with a candidate label set consisting of multiple relevant labels and other noisy *** PML methods typically design a disambiguation strategy to filter out noisy labels by utilizing prior knowledge with extra assumptions,which unfortunately is unavailable in many real ***,because the objective function for disambiguation is usually elaborately designed on the whole training set,it can hardly be optimized in a deep model with stochastic gradient descent(SGD)on *** this paper,for the first time,we propose a deep model for PML to enhance the representation and discrimination *** the one hand,we propose a novel curriculum-based disambiguation strategy to progressively identify ground-truth labels by incorporating the varied difficulties of different *** the other hand,consistency regularization is introduced for model training to balance fitting identified easy labels and exploiting potential relevant *** experimental results on the commonly used benchmark datasets show that the proposed method significantlyoutperforms the SOTA methods.

关键词： Partial multi-label image classification curriculum-based disambiguation consistency regularization label difficulty candidatelabel set.

Paleoclimatic application of spectral parameters to the eolian red clay of the Jianzha Basin,northeastern margin of the Tibetan Plateau

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Science China Earth Sciences 2024年第6期67卷 1952-1966页

作者： Chaofeng FU Ju’e TIAN Xinwen XU Yougui SONG jun ZUO feng WANG lin CHEN Pengfei li Xiaoke QIANG The School of Earth Science and Resources Chang’an UniversityXi’an 710054China State Key Laboratory of Loess and Quaternary Geology Institute of Earth and EnvironmentCASXi’an 710061China College of Urban and Environmental Science Northwest UniversityXi’an 710069China CAS Center for Excellence in Quaternary Science and Global Change Xi’an 710061China

Reflectance spectroscopy is rapid,inexpensive,and non-destructive and can provide important information about the mineralogy of rocks and *** measured the reflectance spectroscopy of Miocene red clay deposits on the northeastern margin of the Tibetan Plateau,with the aim of developing a rapid methodology for detecting paleoclimatic *** obtained visible/near-infrared(VNIR)and short-wave infrared(SWIR)spectroscopy data from the red clay in the Jianzha Basin,and analyzed their relationship with independent paleoclimatic records,including mineral contents and environmental magnetic *** results show that the VNIR parameters,including D500,D900,R500,and R900(where D and R represent the depth and reflectance of the absorption peaks around 500 and 900 nm,respectively)are temperature-sensitive and correlated with the magnetic susceptibility,frequency-dependent magnetic susceptibility,and the marine δ^(18)O *** results of frequency-domain analysis of the VNIR parameters show that they reflect climate change on orbital *** parameters,such as AS1400,D1400/D1900 and D1900(where AS represents the asymmetry of the absorption peaks around1400 nm),are correlated with the illite and montmorillonite content,and they are sensitive to the weathering *** spectral parameters of the eolian red clay in the Jianzha Basin reflect regional climatic changes caused by the uplift of the Tibetan Plateau at~8.5 Ma and global climatic cooling at~7.2 Ma,and thus they are applicable as both regional and global paleoenvironmental indicators.

关键词： Visible/near-infrared spectroscopy Short-wave infrared spectroscopy Paleoclimatic indicators Red clay Tibetan Plateau

Tailoring chaotic motion of microcavity photons in ray and wave dynamics by tuning the curvature of space

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 107-112页

作者： Wei lin Yechun Ding Yongsheng Wang Peng li Yanpeng Zhang feng Yun feng li Key Laboratory for Physical Electronics and Devices of the Ministry of Education Shaanxi Key Lab of Information Photonic TechniqueSchool of Electronic Science and EngineeringFaculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Electrical and Photonics Engineering Technical University of DenmarkKgs.Lyngby 2800Denmark Center for Regenerative and Reconstructive Medicine Med-X InstituteThe First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061China Solid-State lighting Engineering Research Center Xi’an Jiaotong UniversityXi’an 710049China

Microcavity photon dynamics in curved space is an emerging interesting area at the crossing point of nanophotonics,chaotic science,and non-Euclidean *** report the sharp difference between the regular and chaotic motions of cavity photons subjected to the varying space *** the island modes of regular motion rise in the phase diagram in the curved space,the chaotic modes show special mechanisms to adapt to the space curvature,including the fast diffusion of ray dynamics,and the localization and hybridization of the Husimi wavepackets among different periodic *** observations are unique effects enabled by the combination of the chaotic trajectory,the wave nature of light,and the non-Euclidean orbital motion,and therefore make the system a versatile optical simulator for chaotic science under quantum mechanics in curved space-time.

关键词： microcavity chaotic motion curved space

Mechanism of microarc oxidation on AZ91D Mg alloy induced byβ-Mg_(17)Al_(12) phase

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 712-724页

作者： Dajun Zhai Xiaoping li jun Shen College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution ofβ-Mg_(17)Al_(12)phase in AZ91D Mg *** kinds of nano-particles(ZrO_(2)and TiO_(2))were designed to be added into the substrate of Mg alloy by friction stir processing(FSP).Then,Mg alloy sample designed with different precipitated morphology ofβ-Mg_(17)Al_(12)phase was treated by microarc oxidation(MAO)in Na_(3)PO_(4)/*** characteristics and performance of the MAO coating was analyzed using scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),contact angle meter,and potentiodynamic *** was found that the coarseα-Mg grains in extruded AZ91D Mg alloy were refined by FSP,and theβ-Mg_(17)Al_(12)phase with reticular structure was broken and *** nano-ZrO_(2)particles were pinned at the grain boundary by FSP,which refined theα-Mg grain and promoted the precipitation ofβ-Mg_(17)Al_(12)phase in *** effectively inhibited the“cascade”phenomenon of microarcs,which induced the uniform distribution of discharge *** MAO coating on Zr-FSP sample had good wettability and corrosion ***,TiO_(2)particles were hardly detected in the coating on TiFSP sample.

关键词： AZ91D Mg alloy microarc oxidation friction stir processing ZrO_(2) TiO_(2) β-Mg_(17)Al_(12)