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Microscopic and spectroscopic analysis of atmospheric iron-containing single particles in Lhasa,Tibet

Journal of Environmental Sciences 2024年第7期141卷 40-50页

作者： Junyu Chen Daobin Zhang Yiran Fu jinhu Wang Xiaomei Cui Ci-ren Qu-zong Qiangying Zhang Chan jin Bu duo School of Ecology and Environment Tibet UniversityLhasa 850000China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China

The Tibetan Plateau,known as the“Third Pole”,is currently in a state of perturbation caused by intensified human activity.In this study,56 samples were obtained at the five sampling sites in typical area of Lhasa city and their physical and chemical properties were investigated by TEM/EDS,STXM,and NEXAFS spectroscopy.After careful examination of 3387single particles,the results showed that Fe should be one of the most frequent metal elements.The Fe-containing single particles in irregular shape and micrometer size was about7.8%and might be mainly from local sources.Meanwhile,the Fe was located on the subsurface of single particles and might be existed in the form of iron oxide.Interestingly,the core-shell structure of iron-containing particles were about 38.8%and might be present as single-,dual-or triple-core shell structure and multi-core shell structure with the Fe/Si ratios of 17.5,10.5,2.9 and 1.2,respectively.Meanwhile,iron and manganese were found to coexist with identical distributions in the single particles,which might induce a synergistic effect between iron and manganese in catalytic oxidation.Finally,the solid spherical structure of Fe-containing particles without an external layer were about 53.4%.The elements of Fe and Mn were co-existed,and might be presented as iron oxide-manganese oxide-silica composite.Moreover,the ferrous and ferric forms of iron might be co-existed.Such information can be valuable in expanding our understanding of Fe-containing particles in the Tibetan Plateau atmosphere.

关键词： Fe-containing single particle Irregular shape Core-shell structure Solid spherical structure Transmission electron microscopy Synchrotron X-ray microscopy

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Projective Bundles and Blowing-Ups Ⅱ

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Algebra Colloquium 2024年第1期31卷 57-62页

作者： duo Li School of Mathematics(Zhuhai) Sun Yat-Sen University ZhuhaiGuangdong 519082China

We study the blowing-up X of a smooth projective variety X along a smooth center B that is equipped with a projective bundle structure over a variety Z.If the Picard number p(X)is 1 and dim X is at most 4,we classify ... 详细信息

关键词： blowing-up projective bundle Fano bundle

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Laser powder bed fusion of NiTiFe shape memory alloy via premixed powder: microstructural evolution, mechanical and functional properties

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Rare Metals 2024年第5期43卷 2300-2316页

作者： Bo Yuan jin-Guo Ge Liang Zhang Hong-Jun Chen Long-Sha Wei Yu-duo Zhou Run-Hua Song Institute of Intelligent Manufacturing Technology Shenzhen Polytechnic School of Mechanical and Electrical Engineering Guilin University of Electronic Technology Guangdong Advanced Polymer Composite EngineeringTechnology Research Center Shenzhen Academy of Aerospace Technology Jihua Laboratory Testing Center Jihua Laboratory

High-cost pre-alloyed powder is the bottleneck problem that limits the widespread application of additivemanufactured shape memory alloys. In this work, the lowcost ternary NiTiFe shape memory alloy is fabricated by laser powder bed fusion (LPBF) technique via mechanically mixed pre-alloy NiTi powder and varying contents pure Fe powder (1, 2, 3 wt%). All NiTiFe alloys show a relative density of up to 99.8%by optimizing the LPBF processing parameters. Owing to the heterogeneous nucleation effect of micron-sized Fe particles, both grain refinement and texture weakening are generated in the NiTiFe alloys, accompanied by the reduction of dislocation density. For the room-temperature mechanical properties,the NiTi-3Fe alloy shows the highest microhardness of HV370, but the fracture strength and elongation reduce to1701 MPa and 23%simultaneously. The evolution of mechanical properties is attributed to the high internal defects, low dislocation density and the incoherent oxide.Moreover, the NiTi-3Fe alloy shows the quasi-linear superelasticity behavior; the superelastic recoverable strain of NiTi-1Fe and NiTi-2Fe decreased with the increase in Fe content. This study provided a new-fangled insight for the development of multi-component NiTi-based shape memory alloys by additive manufacturing.

关键词： Additive manufacturing Shape memory alloy Metal matrix composite Microstructure Mechanical properties

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Polyethylenimine-modified graphene quantum dots promote endothelial cell proliferation

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Regenerative Biomaterials 2024年第2期3卷 137-146页

作者： Qirong Xu Chen Li Xiangyan Meng Xinghong duo Yakai Feng School of Chemistry and Chemical Engineering Qinghai University for NationalitiesXining 810007PR China Key Laboratory of National Ethnic Affairs Commission of Resource Chemistry and Ecological Environment Protection on Qinghai-Tibet Plateau Xining 810007PR China institute of Disaster and Emergency Medicine Tianjin UniversityTianjin 300072PR China School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350PR China Key Laboratory of Systems Bioengineering(Ministry of Education) Tianjin UniversityTianjin 300072PR China

Endothelial cell proliferation plays an important role in angiogenesis and treatment of related diseases.The aim of this study was to evaluate the effect of polyethylenimine(PEI)-modified graphene quantum dots(GQDs)gene vectors on endothelial cell prolifera-tion.The GQDs-cationic polymer gene vectors were synthesized by amidation reaction,and used to deliver pzNF580 gene to Human umbilical vein endothelial cells(HUVECs)for promoting their proliferation.The chemical modification of GQDs can ad-just gene vectors'surface properties and charge distribution,thereby enhancing their interaction with gene molecules,which could effectively compress the pZNF580 gene.The CCK-8 assay showed that the cell viability was higher than 80%at higher vector concentration(40μg/mL),demonstrating that the GQDs-cationic polymer gene vectors and their gene complex nanoparticles(NPs)having low cytotoxicity.The results of the live/dead cell double staining assay were consistent with those of the CCK-8 assay,in which the cell viability of the A-GQDs/pZNF580(94.38±6.39%),C-GQDs-PEI-polylactic acid-co-polyacetic acid(PLGA)/pZNF580(98.65±6.60%)and N-GQDs-PEI-PLGA/pZNF580(90.08±1.60%)groups was significantly higher than that of the Lipofectamine 2000/pzNF580(71.98±3.53%)positive treatment group.The results of transfection and western blot experiments showed that the vector significantly enhanced the delivery of plasmid to HUVECs and increased the expression of pZNF580 in HUVECs.In addition,the gene NPs better promote endothelial cell migration and proliferation.The cell migration rate and proliferation ability of C-GQDs-PEI-PLGA/pZNF580 and N-GQDs-PEI-PLGA/pZNF580 treatment groupS were higher than those of Lipofectamine 2000/pDNA treatment group.Modified GQDs possess the potential to serve as efficient gene carriers.They tightly bind gene molecules through charge and other non-covalent interactions,significantly improving the effciency of gene delivery and ensuring the smooth release of genes within the cell.This innovative strategy provides a

关键词： graphene quantum dots polyethylenimine ZNF580 gene endothelial cell proliferation

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From macroautophagy to mitophagy:Unveiling the hidden role of mitophagy in gastrointestinal disorders

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World Journal of Gastroenterology 2024年第23期30卷 2934-2946页

作者： duo-Lun Gao Meng-Ran Lin Nan Ge jin-Tao Guo Fan Yang Si-Yu Sun Department of Gastroenterology Engineering Research Center of Ministry of Education for Minimally Invasive Gastrointestinal Endoscopic TechniquesShengjing Hospital of China Medical UniversityShenyang 110004Liaoning ProvinceChina

In this editorial,we comment on an article titled“Morphological and biochemical characteristics associated with autophagy in gastrointestinal diseases”,which was published in a recent issue of the World Journal of Gastroenterology.We focused on the statement that“autophagy is closely related to the digestion,secretion,and regeneration of gastrointestinal cells”.With advancing research,autophagy,and particularly the pivotal role of the macroautophagy in maintaining cellular equilibrium and stress response in the gastrointestinal system,has garnered extensive study.However,the significance of mitophagy,a unique selective autophagy pathway with ubiquitin-dependent and independent variants,should not be overlooked.In recent decades,mitophagy has been shown to be closely related to the occurrence and development of gastrointestinal diseases,especially inflammatory bowel disease,gastric cancer,and colorectal cancer.The interplay between mitophagy and mitochondrial quality control is crucial for elucidating disease mechanisms,as well as for the development of novel treatment strategies.Exploring the pathogenesis behind gastrointestinal diseases and providing individualized and efficient treatment for patients are subjects we have been exploring.This article reviews the potential mechanism of mitophagy in gastrointestinal diseases with the hope of providing new ideas for diagnosis and treatment.

关键词： Mitophagy Gastrointestinal diseases Parkin Autophagic receptor Colorectal cancer Gastric cancer Inflammatory bowel disease

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Locally Self-Injective Property of FI^(m)

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Algebra Colloquium 2024年第1期31卷 97-110页

作者： duo Zeng LCSM(Ministry of Education) School of Mathematics and Statistics Hunan Normal UniversityChangsha 410081China

We consider the locally self-injective property of the product FI^(m) of category FI of finite sets and injections.Explicitly,we prove that the external tensor product commutes with the coinduction functor,and hence preserves injective modules.As corollaries,every projective FI^(m)-module over a field of characteristic O is injective,and the Serre quotient of the category of finitely generated FI^(m)-modules by the category of finitely generated torsion FI^(m)-modules is equivalent to the category of finite-dimensional FI^(m)-modules.

关键词： self-injective property Serre quotient FI^(m)-modules

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The Return of Ten Thousand Birds

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China Book International 2024年第3期 91-93页

作者： jin duo'er Children's Literature Committee of the Jiangxi Provincial Writers Association

At dawn,when the sun beats its drum,Yingpanxu awakens.Awakening along With it,in addition to Yingpanxu's lush vegetation and curling cooking smoke,are the birds in the forest:egrets,cuckoos,turtledoves,willow warblers,shrikes,white pheasants,long-billed crows,pine hawks.These spirits of the earth,fapping their wings,lightly tracing beautiful arcs through the forests and meadows.The milk-like fog in the forest,and the towering mountains piercing into the clouds,become even more poetic and lively amidst the chorus of bird calls.

关键词： forest smoke mountains

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WSN Mobile Target Tracking Based on Improved Snake-Extended Kalman Filtering Algorithm

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Journal of Beijing Institute of Technology 2024年第1期33卷 28-40页

作者： duo Peng Kun Xie Mingshuo Liu School of Computer and Communication of Lanzhou University of Technology Lanzhou Gansu 730050China

A wireless sensor network mobile target tracking algorithm(ISO-EKF)based on improved snake optimization algorithm(ISO)is proposed to address the difficulty of estimating initial values when using extended Kalman filtering to solve the state of nonlinear mobile target tracking.First,the steps of extended Kalman filtering(EKF)are introduced.Second,the ISO is used to adjust the parameters of the EKF in real time to adapt to the current motion state of the mobile target.Finally,the effectiveness of the algorithm is demonstrated through filtering and tracking using the constant velocity circular motion model(CM).Under the specified conditions,the position and velocity mean square error curves are compared among the snake optimizer(SO)-EKF algorithm,EKF algorithm,and the proposed algorithm.The comparison shows that the proposed algorithm reduces the root mean square error of position by 52%and 41%compared to the SOEKF algorithm and EKF algorithm,respectively.

关键词： wireless sensor network(WSN)target tracking snake optimization algorithm extended Kalman filter maneuvering target

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Dynamic multifunctional metasurfaces:an inverse design deep learning approach

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Photonics Research 2024年第1期12卷 123-133页

作者： ZHI-DAN LEI YI-duo XU CHENG LEI YAN ZHAO DU WANG The Institute of Technological Sciences Wuhan UniversityWuhan 430072China College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Optical metasurfaces(OMs)offer unprecedented control over electromagnetic waves,enabling advanced optical multiplexing.The emergence of deep learning has opened new avenues for designing OMs.However,existing deep learning methods for OMs primarily focus on forward design,which limits their design capabilities,lacks global optimization,and relies on prior knowledge.Additionally,most OMs are static,with fixed functionalities once processed.To overcome these limitations,we propose an inverse design deep learning method for dynamic OMs.Our approach comprises a forward prediction network and an inverse retrieval network.The forward prediction network establishes a mapping between meta-unit structure parameters and reflectance spectra.The inverse retrieval network generates a library of meta-unit structure parameters based on target requirements,enabling end-to-end design of OMs.By incorporating the dynamic tunability of the phase change material Sb2Te3with inverse design deep learning,we achieve the design and verification of dynamic multifunctional OMs.Our results demonstrate OMs with multiple information channels and encryption capabilities that can realize multiple physical field optical modulation functions.When Sb2Te3is in the amorphous state,near-field nano-printing based on meta-unit amplitude modulation is achieved for X-polarized incident light,while holographic imaging based on meta-unit phase modulation is realized for circularly polarized light.In the crystalline state,the encrypted information remains secure even with the correct polarization input,achieving double encryption.This research points towards ultra-compact,high-capacity,and highly secure information storage approaches.

关键词： polarization inverse approach

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Evaluating the stability and volumetric flowback rate of proppant packs in hydraulic fractures using the lattice Boltzmann-discrete element coupling method

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2052-2063页

作者： duo Wang Sanbai Li Rui Wang Binhui Li Zhejun Pan National Key Laboratory of Continental Shale Oil Northeast Petroleum UniversityDaqing163318China Institute of Unconventional Oil&Gas Northeast Petroleum UniversityDaqing163318China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China National Center for Applied Mathematics Shenzhen(NCAMS) Southern University of Science and TechnologyShenzhen518055China National Key Laboratory of Continental Shale Oil Daqing Oilfield of CNPCDaqing163002China Daqing Oilfield Exploration and Development Research Institute DaqingHeilongjiang163712China

The stability and mobility of proppant packs in hydraulic fractures during hydrocarbon production are numerically investigated by the lattice Boltzmann-discrete element coupling method(LB-DEM).This study starts with a preliminary proppant settling test,from which a solid volume fraction of 0.575 is calibrated for the proppant pack in the fracture.In the established workflow to investigate proppant flowback,a displacement is applied to the fracture surfaces to compact the generated proppant pack as well as further mimicking proppant embedment under closure stress.When a pressure gradient is applied to drive the fluid-particle flow,a critical aperture-to-diameter ratio of 4 is observed,above which the proppant pack would collapse.The results also show that the volumetric proppant flowback rate increases quadratically with the fracture aperture,while a linear variation between the particle flux and the pressure gradient is exhibited for a fixed fracture aperture.The research outcome contributes towards an improved understanding of proppant flowback in hydraulic fractures,which also supports an optimised proppant size selection for hydraulic fracturing operations.

关键词： Numerical simulation Hydraulic fracturing Proppant flowback Closure stress Particulate flow

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