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Deformation mechanism and limit support pressure of cutting steel plate during connection between pipes in large spacing using pipe curtain structure method

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Underground Space 2024年第5期18卷 83-96页

作者： Xiang Liu Rui Zhang jun Huang Guang Zhao Qian Fang Annan Jiang Liaoning Key Laboratory of marine Environmental Bridge and Tunnel Engineering Dalian Maritime UniversityDalian 116026China JSTI Group Nanjing 210017China Key Laboratory for Urban Underground Engineering of ministry of Education Beijing Jiaotong UniversityBeijing 100044China

The pipe curtain structure method(PSm)is a novel construction method to control ground deformation *** with the traditional pipe-roofing and pipe jacking method,the connection between pipes in large spacings using PSm is widely acknowledged as a unique construction *** study on this connection procedure is needed to resolve similar cases in that the pipes are inevitably constructed on both sides of existing *** the steel plate during the connection procedure is the first step,which is crucial to control the safety and stability of the surrounding environment and existing *** deformation mechanism and limit support pressure of the cutting steel plate during the connection between pipes in large spacings are studied in this paper,relying on the undercrossing Yifeng gate tower project of Jianning West Road River Crossing Channel in Nanjing,China.A modified 3D wedge-prism failure model is proposed using the 3D discrete element *** with Terzaghi loose earth pressure theory and the limit equilibrium theory,the analytical solutions for the limit support pressure of the excavation face of the cutting steel plate are *** modified 3D wedge-prism failure model and corresponding analytical solutions are categorised into two cases:(a)unilateral cutting scheme,and(b)bilateral cutting *** analytical solutions for the two cases are verified from the numerical simulation and in-situ data and compared with the previous *** comparative analysis between the unilateral and bilateral cutting schemes indicates that the bilateral cutting scheme can be adopted as a *** bilateral cutting scheme saves more time and induces less ground deformation than the unilateral one due to the resistance generated from the superimposed *** addition,the parametric sensitivity analysis is carried out using an orthogonal experimental *** main influencing factors arranged from high to low are the pipe sp

关键词： Pipe curtain structure method Wedge-prism failure model Limit support pressure Discrete element method Connection between pipes

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mXene-based hybrid materials for electrochemical and photoelectrochemical H_(2) generation

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Journal of Energy Chemistry 2024年第6期93卷 111-125,I0004页

作者： jun Young Kim Seung Hun Roh Chengkai Xia Uk Sim jung Kyu Kim School of material Science and Engineering North University of ChinaTaiyuan 030051China School of Chemical Engineering Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea Hydrogen Energy Technology Laboratory Korea Institute of Energy Technology(KENTECH)NajuJeollanamdo 58330Republic of Korea SKKU Advanced Institute of Nano Technology(SAINT) Sungkyunkwan University(SKKU)2066Seobu-roJangan-guSuwon 16419Republic of Korea

The conversion of solar energy to produce clean hydrogen fuel through water splitting is an emerging strategy for efficiently storing solar energy in the form of solar *** aligns with the increasing global demand for the development of an ideal energy alternative to fossil fuels that does not emit greenhouse ***(EC) and photoelectrochemical(PEC) water splitting technologies have garnered significant attention worldwide for advanced hydrogen solar fuel production in recent *** achieve sustainable green H_(2) production,it is essential to create efficient catalyst materials that are low-cost and can replace expensive noble metal-based *** characteristics make them an ideal catalyst material for the ***-dimensional mXenes with m_(n+1)X_(n) structure have been identified as a promising option for EC and PEC water splitting due to their superior hydrophilicity,metal-like conductivity,large surface area,and adjustable surface ***,we present a summary of recent advancements in the synthesis and performance enhancement methods for mXene hybrid materials in hydrogen production through EC and PEC water ***,we examine the challenges and insights associated with the rational design of mXene-based hybrid materials to facilitate efficient water splitting for sustainable solar fuel production.

关键词： mXene Hybrid materials EC PEC HER OER Water splitting

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In-situ measurement via the flow-through method and numerical simulations for radon exhalation during measurements of the radon exhalation rate

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Nuclear Science and Techniques 2024年第7期35卷 192-207页

作者： ming Xia Yong-jun Ye Shan-Wei Shang Ting Yu Dai-Jia Chen School of Resources Environment and Safety Engineering University of South ChinaHengyang421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium mining and Hydrometallurgy University of South ChinaHengyang421001China

Small-scale measurements of the radon exhalation rate using the flow-through and closed-loop methods were conducted on the surface of a uranium tailing pond to better understand the differences between the two *** abnormal radon exhalation behavior was observed,leading to computational fluid dynamics(CFD)-based simulations in which dynamic radon migration in a porous medium and accumulation chamber was *** on the in-situ experimental and numerical simulation results,variations in the radon exhalation rate subject to permeability,flow rate,and insertion depth were quantified and *** in-situ radon exhalation rates measured using the flow-through method were higher than those measured using the closed-loop method,which could be explained by the negative pressure difference between the inside and outside of the chamber during the *** consistency of the variations in the radon exhalation rate between the experiments and simulations suggests the reliability of CFD-based techniques in obtaining the dynamic evolution of transient radon exhalation rates for diffusion and convection at the porous medium-air *** synergistic effects of the three factors(insertion depth,flow rate,and permeability)on the negative pressure difference and measured exhalation rate were quantified,and multivariate regression models were established,with positive correlations in most cases;the exhalation rate decreased with increasing insertion depth at a permeability of 1×10^(−11) m^(2).CFD-based simulations can provide theoretical guidance for improving the flow-through method and thus achieve accurate measurements.

关键词： Radon exhalation Flow-through Numerical simulation Accumulation chamber multivariate regression

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Supermassive black holes triggered by QCD axion bubbles

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Communications in Theoretical Physics 2024年第5期76卷 134-139页

作者： Hai-jun Li Ying-Quan Peng Wei Chao Yu-Feng Zhou Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical Physics Asia-Pacific Beijing/HangzhouChina

Supermassive black holes(SmBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still *** this paper,we investigate the formation of SmBHs from the quantum chromodynamics(QCD)axion *** this case,primordial black holes(PBHs)are considered as the seeds of SmBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after *** QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase *** consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))m⊙for the axion decay constant f_(a)∼■(10^(16))*** PBHs at this mass region may account for the seeds of SmBHs.

关键词： supermassive black holes primordial black holes quantum chromodynamics axion

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Circadian disturbance induces erectile dysfunction by impairing endothelial function

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Asian Journal of Andrology 2024年第2期26卷 205-211页

作者： Tao Li Yi-Ting Jiang Xin-Zhu Qi Peng Chen jun-Hao Zhang Fu Luo jun Qiao Jiang Gu Guang-Shi Du Qiang Wang Department of Urology Affiliated Hospital of Guizhou Medical UniversityGuiyang 550004China Department of Urology Guizhou Provincial People's HospitalGuiyang 550002China Department of Otorhinolaryngology Affiliated Hospital of Guizhou Medical UniversityGuiyang 550004China Guizhou Institute for Food and Drug Control Guiyang 550004China Department of Reproductive Center Guizhou Provincial People's HospitalGuiyang 550002China Translational medicine Research Center of Guizhou medical University Guiyang 550025China

In order to explore the impact of circadian disturbance on erectile function,we randomly divided 24 adult male rats into groups of control(light on at 8:00 *** off at 8:00 p.m.),dark/dark(DD;constant dark),light/light(LL;constant light),and shift dark/light(DL;light off at 8:00 *** on at 8:0o p.m.).Four weeks later,erectile function was measured and corpora cavernosa were harvested for *** maximum intracavernous pressure(mlcP)and mCP/mean arterial pressure(mAP)ratio in the DD,LL,and DL groups were significantly lower than that in the control *** LL and DL groups showed significantly attenuated endothelial nitric oxide synthase(eNOS),while DD,LL,and DL showed reduced neuronal nitric oxide synthase(nNOS)at both mRNA and protein *** production of nitric oxide(NO)and cyclic guanosinemonophosphate(cGmP)was inhibited by altered light/dark cycles to varying *** disturbance impaired endothelial function and contributed to erectile *** the core circadian elements,mRNA expression of circadian locomotor output cycles kaput(Clock)and brain/muscle aryl-hydrocarbon receptor nuclear translocator-like protein 1(Bmal1)was elevated in the DL group,but their protein expression was not significantly ***,LL,and DL increased period 1(Per1)and Per3 levels,while LL and DL increased PER1 *** significant difference was found for Per2levels,and PER2 and PER3 concentrations were not significantly ***,LL and DL significantly increased cryptochrome-1(CRY1)and CRY2 at both mRNA and protein *** altered light/dark rat model showed that circadian disturbance contributed to erectile dysfunction probably by impairing endothelial ***,the core circadian elements were detected in the corpora cavernosa,but these were ***,which circadian element regulates erectile function and how it works need further analysis.

关键词： circadian disturbance endothelial function erectile function light/dark cycle NO/cGmP

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Numerical simulation study on the mold strength of magnetic mold casting based on a coupled electromagnetic-structural method

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China Foundry 2024年第5期21卷 577-587页

作者： Wei-li Peng Jian-hua Zhao Cheng Gu Ya-jun Wang College of materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for magnesium Alloys Chongqing UniversityChongqing 400044China National Key Laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China

The properties of the magnetic mold in magnetic mold casting directly determine the quality of the final cast *** this study,the magnetic mold properties in magnetic mold casting,were studied utilizing a coupled electromagnetic-structural method through numerical *** study investigated key factors including equivalent stress,the distribution of tensile and compressive stresses,and the area ratio of tensile *** compared molds made entirely of magnetic materials with those made partially of magnetic *** results indicate that as current increases from 4 A to 8 A,both the initial magnetic mold and the material-replaced magnetic mold initially show an increasing trend in equivalent stress,tensile-compressive stress,and the area ratio of tensile stress,peaking at 6 A before *** material replacement,the area ratio of tensile stress at 6 A decreases to 19.84%,representing a reduction of 29.72%.magnetic molds comprising a combination of magnetic and non-magnetic materials exhibit sufficient strength and a reduced area ratio of tensile stress compared to those made entirely from magnetic *** study provides valuable insights for optimizing magnetic mold casting processes and offers practical guidance for advancing the application of magnetic molds.

关键词： magnetic mold casting coupled electromagnetic-structural method numerical simulation stress analysis

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Binder-induced ultrafast ■-intercalation toward a high-voltage,high-power and long-cycling zinc–graphite dual-ion battery

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Rare metals 2024年第10期43卷 5017-5029页

作者： Gen Li Xiao-jun Shi Ting Dong Qian Yu Zhi-Fei mao Xin-Hua Liu Rui Wang Bei-Bei He jun Jin Yan-Sheng Gong Huan-Wen Wang Engineering Research Center of Nano-Geomaterials of ministry of Education Faculty of Material Science and ChemistryChina University of Geosciences College of Resources and Environment South-Central Minzu University School of Transportation Science and Engineering Beihang University

metallic zinc is an ideal anode material owing to its high theoretical capacity (819 mAh·g-1),ecofriendliness,low cost and high safety,which have driven fast development of Zn-ion batteries （ZIBs）.However,the practical application of current ZIBs is significantly restricted by irregular dendrite growth of zinc anode and the low working voltage （usuallym LiPF6in the ethyl methyl carbonate （EmC） *** the corrosion interaction of Li+ions,Zn2+can be easily dissolved from Zn anode into the electrolyte to enable dendrite-free Zn2+plating/stripping at the ***,an aqueous carboxymethyl cellulose （CmC） binder is employed to generate a robust cathode electrolyte interface （CEI） layer on the graphite cathode,which renders ultrafast PF6--de-/intercalation into *** resultant Zn–graphite DIB operates stably at a high cut off voltage of 3.2 V,corresponding to an average output voltage of 2.2 *** 9000cycles at 5C,the high capacity retention of 95.9% can be achieved with～100%Coulomb *** on the mass of cathode material,our Zn–graphite battery exhibits ultrafast rate capability （60 C,a discharge time of 44 s） and high energy/power densities (208 Wh·kg-1at 214 W·kg-1;142 Wh·kg-1at 8692 W·kg-1),which holds great promise for large-scale energy storage.

关键词： Binder Graphite High-voltage PF6−-de-/intercalation Zn-ion batteries

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A novel dandelion-based bionic proppant and its transportation mechanism in different types of fractures

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Petroleum Science 2024年第4期21卷 2583-2599页

作者： jun Li ming-Yi Wu Xu Han Si-Yuan He Ze-Yu Lin State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University Sichuan Particles Energy and Technology Co. Ltd Chongqing Industry Polytechnic College Petroleum Systems Engineering Faculty of Engineering and Applied Science University of Regina

Low-permeability reservoirs are generally characterized by low porosity and low permeability. Obtaining high production using the traditional method is technologically challenging because it yields a low reservoir recovery factor. In recent years, hydraulic fracturing technology is widely applied for efficiently exploiting and developing low-permeability reservoirs using a low-viscosity fluid as a fracturing ***, the transportation of the proppant is inefficient in the low-viscosity fluid, and the proppant has a low piling-up height in fracture channels. These key challenges restrict the fluid(natural gas or oil) flow in fracture channels and their functional flow areas, reducing the profits of hydrocarbon *** study aimed to explore and develop a novel dandelion-bionic proppant by modifying the surface of the proppant and the fiber. Its structure was similar to that of dandelion seeds, and it had high transport and stacking efficiency in low-viscosity liquids compared with the traditional ***, the transportation efficiency of this newly developed proppant was investigated experimentally using six different types of fracture models(tortuous fracture model, rough fracture model,narrow fracture model, complex fracture model, large-scale single fracture model, and small-scale single fracture model). Experimental results indicated that, compared with the traditional proppant, the transportation efficiency and the packing area of the dandelion-based bionic proppant significantly improved in tap water or low-viscosity fluid. Compared with the traditional proppant, the dandelionbased bionic proppant had 0.1-4 times longer transportation length, 0.3-5 times higher piling-up height, and 2-10 times larger placement area. The newly developed proppant also had some other extraordinary features. The tortuosity of the fracture did not influence the transportation of the novel proppant. This proppant could easily enter the branch fracture and n

关键词： Dandelion-based bionic proppant Low-viscosity fracturing fluid Unconventional reservoir Volumetric fracturing stimulation

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Superatomic Ag_(58) nanoclusters incorporating a [mS_(4)@Ag_(12)]^(2+)(m = mo or W) kernel show aggregation-induced emission

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Chinese Chemical Letters 2024年第10期35卷 452-456页

作者： jun-Jie Fang Zheng Liu Yun-Peng Xie Xing Lu State Key Laboratory of materials Processing and Die&mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

In core-shell silver nanoclusters,the control of core structure presents a more formidable challenge compared to that of the shell ***,we report the successful synthesis and characterization of four distinct silver thiolate nanoclusters[mS_(4)@Ag_(12)@Ag_(46)S_(24)(dppb)_(12)](m=mo or W),each incorporating a cup-like[mS_(4)@Ag_(12)]^(2+)*** nanoclusters were meticulously prepared using(NH_(4))2mo S4or(NH_(4))_(2)WS_(4)as both a template and a controlled source of ***,we have observed a unique configuration within these eight-electron superatomic Ag_(58) nanoclusters,where the zerovalent Ag atoms reside exclusively within the inner[mS_(4)@Ag_(12)]^(2+)*** stands in contrast to other superatomic clusters possessing an Ag(0)***,the introduction of phenyl-containing compounds during the synthesis process induced a transformation in the space group symmetry from C_(2)/c to I 4ˉ.This transformative effect was found to originate from the interplay between adjacent 1,4-bis(diphenylphosphino)butane(dppb)ligands,which facilitated enhanced emission through aggregationinduced intermolecular interactions,specifically C-H···π***,our findings contribute substantively to the understanding of the intricate relationship between nanocluster structures and their corresponding properties,shedding light on the crucial roles played by templates and diphosphine ligands in this context.

关键词： Superatom Silver nanocluster Template synthesis Photoluminescence Aggregation-induced emission

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Diagenetic evolution and reservoir quality of the Oligocene sandstones in the Baiyun Sag, Pearl River mouth Basin, South China Sea

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Acta Oceanologica Sinica 2024年第2期43卷 67-82页

作者： Bing Tian Shanshan Zuo Youwei Zheng Jie Zhang Jiayu Du jun Tang Institute of mining and Coal Inner Mongolia University of Science and TechnologyBaotou 014010China Institute of Science Inner Mongolia University of Science and TechnologyBaotou 014010China

The Oligocene Zhuhai sandstones are significant reservoirs for hydrocarbons in the Baiyun Sag, South China *** effective appraisal, exploration and exploitation of such a deep-water hydrocarbon sandstone, samples of five wells from depths of 850 m to 3 000 m were studied. A series of comprehensive petrographic and geochemical analyses were performed to unravel the diagenetic features and their impact on the reservoir ***, the sandstones are dominated by feldspathic litharenites and lithic arenites with fine to medium grain sizes and moderate to good sorting. The reservoir quality varies greatly with a range of porosity from 0.2% to 36.1% and permeability from 0.016 ×10~(–3) μm~2 to 4 301 ×10~(–3) μm~2, which is attributed to complex diagenetic evolution related to sedimentary facies;these include compaction, cementation of calcite, dolomite, siderite and framboidal pyrite in eogenetic stage;further compaction, feldspar dissolution, precipitation of ferrocalcite and ankerite, quartz cements, formation of kaolinite and its illitization, precipitation of albite and nodular pyrite, as well as hydrocarbon charge in mesogenetic stage. The dissolution of feldspar and illitization of kaolinite provide internal sources for the precipitation of quartz cement, while carbonate cements are derived from external sources related to interbedded mudstones and deep fluid. Compaction is the predominant factor in reducing the total porosity, followed by carbonate cementation that leads to strong heterogeneity. Feldspar dissolution and concomitant quartz and clay cementation barely changes the porosity but significantly reduces the *** high-quality reservoirs can be concluded as medium-grained sandstones lying in the central parts of thick underwater distributary channel sandbodies(>2 m) with a high content of detrital quartz but low cement.

关键词： Baiyun Sag Oligocene Zhuhai Formation diagenesis reservoir quality

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