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Seabed structures and foundations related to deep-sea resource development:A review based on design and research

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Deep Underground Science and Engineering 2024年第2期3卷 131-148页

作者： Shengjie Rui Haojie Zhang Hang xu Xing Zha Mengtao xu Kanmin Shen Key Laboratory of Offshore Geotechnics and Material of Zhejiang Province College of Civil Engineering and ArchitectureZhejiang UniversityHangzhouChina Advanced Modelling Offshore EnergyNorwegian Geotechnical InstituteOsloNorway Geotechnical Technology center(Overseas Engineering center) PowerChina Huadong Engineering Corporation LimitedHangzhouChina

The deep‐sea ground contains a huge amount of energy and mineral resources,for example,oil,gas,and *** infrastructures such as floating structures,seabed structures,and foundations have been developed to exploit these *** seabed structures and foundations can be mainly classified into three types:subsea production structures,offshore pipelines,and *** study reviewed the development,installation,and operation of these infrastructures,including their structures,design,installation,marine environment loads,and *** this basis,the research gaps and further research directions were explored through this literature ***,different floating structures were briefly analyzed and reviewed to introduce the design requirements of the seabed structures and ***,the subsea production structures,including subsea manifolds and their foundations,were reviewed and ***,the basic characteristics and design methods of deep‐sea pipelines,including subsea pipelines and risers,were analyzed and ***,the installation and bearing capacity of deep‐sea subsea anchors and seabed trench influence on the anchor were *** the review,it was found that marine environment conditions are the key inputs for any offshore structure *** fabrication,installation,and operation of infrastructures should carefully consider the marine loads and geological *** structures have their own mechanical *** fatigue and stability of pipelines mainly depend on the soil‐structure *** selection should consider soil types and possible trench *** focuses and research gaps can provide a helpful guide on further research,installation,and operation of deep‐sea structures and foundations.

关键词： anchors floating structures pipelines risers subsea foundations

Insights into the kinetics–morphology relationship of 1-, 2-, and 3D TiNb_(2)O_(7) anodes for Li-ion storage

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Nano Research 2024年第4期17卷 2770-2780页

作者： Wenlei xu Yaolin xu Veronika Grzimek Andrea Martin Thorsten Schultz Patrícia ARusso Yan Lu Norbert Koch Nicola Pinna Department of chemistry IRIS Adlershof and the Center for the Science of Materials BerlinHumboldt-Universität zu BerlinBrook-Taylor-Str.212489 BerlinGermany Department of Electrochemical Energy Storage Helmholtz-Zentrum Berlin für Materialien und EnergieHahn-Meitner-Platz 114109 BerlinGermany Institut für Physik and IRIS Adlershof Humboldt-Universität zu BerlinBrook-Taylor-Str.212489 BerlinGermany joint Research Group of Molecular Systems Helmholtz-Zentrum Berlin für Materialien und Energie12489 BerlinGermany

Understanding the influence of electrode material’s morphology on electrochemical behavior is of great significance for the development of rechargeable batteries,however,such studies are often limited by the inability to precisely control the morphology of electrode ***,nanostructured titanium niobium oxides(TiNb_(2)O_(7))with three different morphologies(one-dimensional(1D),two-dimensional(2D),and three-dimensional(3D))were synthesized via a facile microwave-assisted solvothermal *** influence of the morphological dimension of TiNb_(2)O_(7) as electrode material on the electrochemical performance in Li-ion batteries(LIBs)and the underlying correlation with the electrochemical kinetics were studied in detail.2D TiNb_(2)O_(7)(TNO-2D)shows a superior rate capability and cycling stability,associated with improved kinetics for charge transfer and Li-ion diffusion,compared to the 1D and 3D *** X-ray diffraction measurements reveal the structural stability and crystallographic evolution of TNO-2D upon lithiation and delithiation and correlate the Li-ion diffusion kinetics with the lattice evolution during battery charge and ***,carbon-coated TNO-2D achieves enhanced rate capability(205 mAh·g^(-1) at 50 c)and long-term cycling stability(87%after 1000 cycles at 5 c).This work provides insights into the rational morphology design of electrode materials for accelerated charge transfer and enhanced fast-charging capability,pushing forward the development of electrode materials for high-power rechargeable batteries in future energy storage.

关键词： morphological dimension electrochemical kinetics lithium-ion batteries TiNb_(2)O_(7) structural evolution

Divergent defluorocarboxylation of α-cF_(3) alkenes with formate via photocatalyzed selective mono-or triple c-F bond cleavage

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Science china chemistry 2024年第1期67卷 368-373页

作者： Xing-Yu Wang Pei xu Wen-Wen Liu Hao-Qiang jiang Song-Lei Zhu Dong Guo xu Zhu jiangsu Key Laboratory of New Drug Research and clinical Pharmacy School of PharmacyXuzhou Medical UniversityXuzhou 22100China

Unprecedented divergent synthesis of gem-difluorovinylacetic acid and glutaric acid derivatives fromα-cF_(3)alkenes with formate as the carbonyl source was *** reaction can undergo selective mono-or triple c-F bond cleavage by simply switching the photocatalyst and hydrogen atom transfer(HAT)catalyst under visible-light-induced conditions at room *** acts as both the c1 source and the reductant through the generation of cO_(2)^(·-)species,which underwent Giese radical addition to electron-deficient alkenes to trigger the consecutive c-F bond cleavage and carboxylation process.

关键词： c-F bond activation defluorocarboxylation carbon dioxide radical anion visible light

A Rendezvous Mission to the Second Earth Trojan Asteroid 2020 XL_5 with Low-Thrust Multi-Gravity Assist Techniques

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Research in Astronomy and Astrophysics 2024年第1期24卷 245-264页

作者： Shi-Hai Yang Bo xu Xin Li School of Aeronautics and Astronautics Sun Yat-sen UniversityShenzhen 518107China

As the second of Earth's Trojan asteroids, 2020 XL_(5) is worthy of rendezvous and even sample return missions in many aspects. In this paper, a rendezvous mission to Earth's second Trojan asteroid 2020 XL_(5) is ***, due to its high inclination and large eccentricity, direct impulsive transfer requires large amounts of fuel consumption. To address this challenge, we explore the benefits of electric propulsion and multi-gravity assist techniques for interplanetary missions. These two techniques are integrated in this mission design. The design of a low-thrust gravity-assist(LTGA) traj.c.ory in multi-body dynamics is thoroughly investigated,which is a complex process. A comprehensive framework including three steps is presented here for optimization of LTGA traj.c.ories in multi-body dynamics. The rendezvous mission to 2020 XL_(5) is designed with this three-step approach. The most effective transfer sequence among the outcomes involves Earth–Venus–Earth–Venus-2020 XL_(5). Numerical results indicate that the combination of electric propulsion and multi-gravity assists can greatly reduce the fuel consumption, with fuel consumption of 9.03%, making it a highly favorable choice for this rendezvous mission.

关键词： minor planets asteroids:general celestial mechanics Planetary Systems

cO oxidation under lean and stoichiometric conditions over ceriazirconia with very low metal contents(cu,co,Ag and Pt)

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journal of Rare Earths 2024年第9期42卷 1669-1681,I0002页

作者： j.c.Martínez-Munuera M.P.Yeste A.García-García McMA Group Department of Inorganic Chemistry and Institute of MaterialsUniversity of AlicanteCarretera de San Vicente del Raspeig s/n03690San Vicente del RaspeigAlicanteSpain Solid chemistry and catalysis Group Department of Materials ScienceMetallurgic Engineering and Inorganic ChemistryInstitute of Electronic Microscopy and Materials ResearchUniversity of CádizAp.40E-11510Puerto RealCádizSpain

In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the cO oxidatio n reaction(under lean and stoichiometric conditions),trying to emulate those conditions found in a diesel oxidation catalyst(DOc) system from a diesel engine and those encountered under gasoline exhaust(λ=1).The metals chosen are cu,co,Ag and Pt(as a reliable benchmark).The results reveal enormous differences among reducibility and catalytic activity despite quite similar structural and textural properties of the catalysts,showing differences among dispersion(Ag-catalyst seems to present a low level of dispersion).This catalyst seems to be characterised,as well,by a strong electronic interaction between ce and Ag centres which is suggested to yield an improved reducibility under H_(2)-TPR ***,the order in catalytic activity(cu>Ag>co≈Pt>>support) seems not to follow the order found in reducibility and the cu-catalyst seems to be the most active independently on the reaction conditions,yielding nearly overlapped cO oxidation catalytic *** restingly,a stro ng correlation between the catalytic activity under the two conditions tested and the OSc values of the ce_(0.8)Zr_(0.2)O_(2)-supported metal catalysts is ***,OSc parameter measured at 150℃ can be used as a relevant descriptor to evaluate the cO oxidation activity at low and medium conversions for the investigated catalysts,much better than the H_(2)-TPR measurements.

关键词： cO oxidation Low metal content ceria-zirconia copper species OSc parameter Rare earths

Gravitational wave footprints from Higgs-portal scalegenesis with multiple dark chiral scalars

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chinese Physics c 2024年第4期48卷 209-221页

作者： He-xu Zhang Shinya Matsuzaki Hiroyuki Ishida center for Theoretical Physics and college of Physics Jilin UniversityChangchun 130012China center for Liberal Arts and Sciences Toyama Prefectural UniversityToyama 939-0398Japan

We discuss the gravitational wave(GW)spectra predicted from the electroweak scalegenesis of the Higgs portal type with a large number of dark chiral flavors,which many flavor QcD would underlie and give the dynamical explanation of the negative Higgs portal coupling required to trigger the electroweak symmetry *** employ the linear-sigma model as the low-energy description of dark many flavor QcD and show that the model undergoes ultra-supercooling due to the produced strong first-order thermal phase transition along the(approximately realized)flat direction based on the Gildener-Weinberg *** through evaluation of the bubble nucleation/percolation,we address the reheating and relaxation processes,which are generically non-thermal and *** the reheating epoch in terms of the e-folding number,we propose proper formulae for the redshift effects on the GW frequencies and signal *** then turns out that the ultra-supercooling predicted from the Higgs-portal scalegenesis generically yields none of GW signals with the frequencies as low as nano Hz,unless the released latent heat is transported into another sector other than reheating the ***,models of this class prefer to give the higher frequency signals and still keeps the future prospected detection sensitivity,like at LISA,BBO,and DEcIGO,*** also find that with large flavors in the dark sector,the GW signals are made further smaller and the peak frequencies *** phenomenological consequences related to the multiple chiral scalars include the prediction of dark pions with the mass much less than TeV scale,which is also briefly addressed.

关键词： gravitational wave electroweak scalegenesis many flavor QcD

The siphonic energy transfer between hot solar wind and cold martian ionosphere through open magnetic flux rope

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Fundamental Research 2024年第4期4卷 882-889页

作者： Xiaojun xu Lou-chuang Lee Qi xu Qing chang jing Wang Ming Wang Shaosui xu christian Mosti charles j.Farrugia Xing Wang Yudong Ye Zilu Zhou Lei Luo Peishan He Shaoguan cheng State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China cNSA Macao center for Space Exploration and Science Macao 999078China Institute of Earth Science Academia SinicaTaipei 115029China Institute of Space Science and Applied Technology Harbin Institute of TechnologyShenzhen 518000China Planetary Environmental and Astrobiological Research Laboratory(PEARL) School of Atmospheric SciencesSun Yat-sen UniversityZhuhai 519000China Nanjing University of Information Science and Technology Nanjing 210000China Space ScienceLaboratory Universityof CaliforniaBerkeleyCA94320USA Space Research Institute Austrian Academy of SciencesGraz 8010Austria University of New Hampshire NH 03824USA

A mechanism for energy transfer from the solar wind to the Martian ionosphere through open magnetic flux rope is proposed based on the observations by Mars Atmosphere and Volatile EvolutioN(MAVEN).The satellite was located in the dayside magnetosheath at an altitude of about 70o km above the northern *** between the hot solar wind protons and the cold heavy ions/neutrals in the subsolar region can cool the protons and heat the heavy *** a result,the magnetosheath protons are siphoned into the ionosphere due to the thermal pressure gradient of protons and the heated heavy ions escape along the open magnetic field *** direct collisions in the lower-altitude region were not detected,this physical process is demonstrated by MAVEN measurements of enhanced proton density,decreased proton temperature and oppositely directed motions of hot and cool protons within the flux rope,which are very different from the observational features of the flux transfer events near the Earth's *** mechanism could universally exist in many contexts where a collisionless plasma region is connected to a collisional plasma *** reconstructing the magnetic geometry and the cross-section of the flux rope using the Grad-Shafranov technique,the ion loss rates are quantitatively estimated to be on the order of 1023 s-l,which is much higher than previously estimated.

关键词： Mars Flux rope Solarwind Ionosphere Ion loss

Post-acute ischemic stroke hyperglycemia aggravates destruction of the blood-brain barrier

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Neural Regeneration Research 2024年第6期19卷 1344-1350页

作者： Tianqi xu jianhong Yang Yao xu Xiaofeng Wang Xiang Gao jie Sun chenhui Zhou Yi Huang Department of Neurology The First Affiliated Hospital of Ningbo University Department of General Surgery The First Affiliated Hospital of Ningbo University Department of Neurosurgery The First Affiliated Hospital of Ningbo University Key Laboratory of Precision Medicine for Atherosclerotic Diseases of Zhejiang Province

Post-acute ischemic stroke hyperglycemia increases the risk of hemorrhagic transformation, which is associated with blood-brain barrier disruption. Brain microvascular endothelial cells are a major component of the blood-brain barrier. Intercellular mitochondrial transfer has emerged as a novel paradigm for repairing cells with mitochondrial dysfunction. In this study, we first investigated whether mitochondrial transfer exists between brain microvascular endothelial cells, and then investigated the effects of post-acute ischemic stroke hyperglycemia on mitochondrial transfer between brain microvascular endothelial cells. We found that healthy brain microvascular endothelial cells can transfer intact mitochondria to oxygen glucose deprivation-injured brain microvascular endothelial cells. However, post-oxygen glucose deprivation hyperglycemia hindered mitochondrial transfer and exacerbated mitochondrial dysfunction. We established an in vitro brain microvascular endothelial cell model of the blood-brain barrier. We found that post-acute ischemic stroke hyperglycemia reduced the overall energy metabolism levels of brain microvascular endothelial cells and increased permeability of the blood-brain barrier. In a clinical study, we retrospectively analyzed the relationship between post-acute ischemic stroke hyperglycemia and the severity of hemorrhagic transformation. We found that post-acute ischemic stroke hyperglycemia serves as an independent predictor of severe hemorrhagic transformation. These findings suggest that post-acute ischemic stroke hyperglycemia can aggravate disruption of the blood-brain barrier by inhibiting mitochondrial transfer.

关键词： acute ischemic stroke blood-brain barrier brain microvascular endothelial cells mitochondrial transfer stress hyperglycemia

Effect of Heat Treatment on Microstructure and Mechanical Properties of Multiscale Sic_p Hybrid Reinforced 6061 Aluminum Matrix composites

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journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 174-181页

作者：吴健铭许晓静 ZHANG xu LUO Yuntian LI Shuaidi HUANG Lin Institute for Advanced Manufacturing and Modern Equipment Technology Jiangsu UniversityZhenjiang 212013China

The performance of solid solution aging treatment on aluminum matrix composites prepared by powder metallurgy and reinforced with 6061 aluminum alloy powder as matrix;meanwhile, nano silicon carbide particles(nm Si cp), submicron silicon carbide particles(1 μm Si cp) and Ti particles were studied. The Al/Si cp composite powder was prepared by high-energy ball milling, and then cold-pressed, sintered, hotextruded, and then heat-treated with different solution temperatures and aging times for the extruded composites. Optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy(EDS), X-ray diffractometer(XRD) and extrusion testing were used to analyze and test the microstructure and mechanical properties of aluminum matrix composites. The results show that after the multi-stage solid solution at 530 ℃×2 h+535 ℃×2 h+540 ℃×2 h, the particles are mainly equiaxed grains and uniformly distributed. There is no reinforcement agglomeration, and the surface is dense and the insoluble phase is basically dissolved. In the matrix, the strengthening effect is good, and the hardness and compressive strength are 179.43 HV and 680.42 MPa, respectively. Under this solution process, when the aluminum matrix composites are aged at 170 ℃ for 10 h, the hardness and compressive strength can reach their peaks and increase to 195.82 HV and 721.48 MPa, respectively.

关键词： aluminum matrix composites Si c particles multiscale hybrid enhancement heat treatment mechanical properties