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A novel and promising engineering application of carbon dots:Enhancing the chloride binding performance of cement

Chinese Chemical Letters 2024年第6期35卷 409-416页

作者： Wu-Jian Long Yang Yu Chuang He Guangdong Provincial key laboratory of Durability for Marine Civil Engineering Key Lab of Coastal Urban Resilient InfrastructureMOECollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China

Corrosion of reinforcement induced by chloride invasion is extensively considered as the dominating deterioration mechanism of reinforced concrete(RC)structures,leading to serious safety hazards and tremendous economic ***,it still lacks well dispersive and cost-efficient nanomaterials to improve the anti-chloride-corrosion ability of RC ***,specific carbon dots(CDs)with high dispersity and low cost are deliberately designed,successfully prepared by hydrothermal processing,and then firstly applied to immensely enhance chloride binding performance of cement,thereby contributing to suppressing the corrosion of ***,the tailored CDs are composed of the carbon core with highly crystalline sp^(2)C structures and oxygen-containing groups connecting on the carbon core;The typical equilibrium test confirms that with respect to that of the blank cement paste,the chloride binding capacity of cement paste involving 0.2 wt%(by weight of cement)CDs is increased by 109% after 14-day exposure to 3 mol/L Na Cl solution;according to comprehensive analyses of phase compositions,the chloride binding mechanism of CDs-modified cement is rationally attributed to the fact that the incorporation of CDs advances the formation of calcium silicate hydrate(C-S-H)gels and Friedel's salt(Fs),thus enormously enhancing the physically adsorbed and chemically bound chloride ions of cement *** work not only firstly provides a novel high-dispersity and low-cost nanomaterial toward the durability enhancement of RC structures,but also broadens the application of CDs in the field of engineering,conducing to stimulating their industrialization development.

关键词： Carbon dots Chloride binding Cement Chloride binding mechanism Friedel’s salt

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Equilibrium Reinsurance Strategy and Mean Residual Life Function

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 758-777页

作者： Dan-ping LI Lv CHEN Lin-yi QIAN Wei WANG School of Statistics Key Laboratory of Advanced Theory and Application in Statistics and Data Science-MOEEast China Normal UniversityShanghai 200062China Academy of Statistics and Interdisciplinary Sciences Key Laboratory of Advanced Theory and Application in Statistics and Data Science-MOEEast China Normal UniversityShanghai 200062China School of Mathematics and Statistics Ningbo UniversityNingbo 315211China

In this paper,we analyze the relationship between the equilibrium reinsurance strategy and the tail of the distribution of the *** Mean Residual Life(MRL)has a close relationship with the tail of the distribution,we consider two classes of risk distributions,Decreasing Mean Residual Life(DMRL)and Increasing Mean Residual Life(IMRL)distributions,which can be used to classify light-tailed and heavy-tailed distributions,*** assume that the underlying risk process is modelled by the classical CramérLundberg model *** the mean-variance criterion,by solving the extended Hamilton-Jacobi-Bellman equation,we derive the equilibrium reinsurance strategy for the insurer and the reinsurer under DMRL and IMRL,***,we analyze how to choose the reinsurance premium to make the insurer and the reinsurer agree with the same reinsurance *** find that under the case of DMRL,if the distribution and the risk aversions satisfy certain conditions,the insurer and the reinsurer can adopt a reinsurance premium to agree on a reinsurance strategy,and under the case of IMRL,the insurer and the reinsurer can only agree with each other that the insurer do not purchase the reinsurance.

关键词： mean residual life excess-of-loss reinsurance insurer reinsurer stochastic control

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Rheological study of methane gas hydrates in the presence of micron-sized sand particles

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Chinese Journal of Chemical Engineering 2024年第6期70卷 149-161页

作者： Bohui Shi Shangfei Song Yuchuan Chen Shunkang Fu Lihao Liu Xinyao Yang Haihao Wu Guangjin Chen Jing Gong National Engineering Research Center of Oil and Gas Pipeline transportation Safety MOE Key Laboratory of Petroleum EngineeringBeijing Key Laboratory of Urban Oil and Gas Distribution TechnologyChina University of Petroleum-BeijingBeijing 102249China China's Oil and Gas Exploration and Development Company(CNODC) Beijing 100034China China National Petroleum Corporation Mozambique LDA MaputoMozambique PipeChina West East Pipeline Company Shanghai 200122China

Natural gas hydrates,intricate crystalline structures formed by water molecules and small gas molecules,have emerged as a significant and globally impactful clean energy ***,their commercial exploitation faces challenges,particularly operational disruptions caused by sand-related *** the rheological properties of hydrate slurry,especially in the presence of micron-sized sand particles,is imperative for ensuring the flow assurance of subsea hydrate *** study extensively investigates the rheological properties of sand-containing hydrate *** findings reveal that these slurries exhibit non-Newtonian fluid characteristics,including yield stress,thixotropy,and shear-thinning ***-like elastic features are observed in sand-containing hydrate slurries before yielding,transitioning to viscous behavior after *** with a minimal amount of sand,both static yield stress and yield strain experience substantial changes,correlating with the increase in sand *** research conclusively establishes the thixotropic nature of sand-hydrate slurries,where the viscosity decay rate is directly influenced by the shear *** insights aim to contribute comprehensively to the development of effective flow assurance strategies,ensuring the safe and stable operation of subsea hydrate exploitation.

关键词： Natural gas hydrate production Sand-containing hydrate slurries Yield stress Thixotropy Shear-thinning behavior

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Study of deep transportation and plugging performance of deformable gel particles in porous media

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Petroleum Science 2024年第2期21卷 962-973页

作者： Wen-Jing Zhao Jing Wang Zhong-Yang Qi Hui-Qing Liu National key laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China moe key laboratory of Petroleum Engineering China University of PetroleumBeijing102249China

Deformable gel particles(DGPs) possess the capability of deep profile control and flooding. However, the deep migration behavior and plugging mechanism along their path remain unclear. Breakage, an inevitable phenomenon during particle migration, significantly impacts the deep plugging effect. Due to the complexity of the process, few studies have been conducted on this subject. In this paper, we conducted DGP flow experiments using a physical model of a multi-point sandpack under various injection rates and particle sizes. Particle size and concentration tests were performed at each measurement point to investigate the transportation behavior of particles in the deep part of the reservoir. The residual resistance coefficient and concentration changes along the porous media were combined to analyze the plugging performance of DGPs. Furthermore, the particle breakage along their path was revealed by analyzing the changes in particle size along the way. A mathematical model of breakage and concentration changes along the path was established. The results showed that the passage after breakage is a significant migration behavior of particles in porous media. The particles were reduced to less than half of their initial size at the front of the porous media. Breakage is an essential reason for the continuous decreases in particle concentration, size, and residual resistance coefficient. However, the particles can remain in porous media after breakage and play a significant role in deep plugging. Higher injection rates or larger particle sizes resulted in faster breakage along the injection direction, higher degrees of breakage, and faster decreases in residual resistance coefficient along the path. These conditions also led to a weaker deep plugging ability. Smaller particles were more evenly retained along the path, but more particles flowed out of the porous media, resulting in a poor deep plugging effect. The particle size is a function of particle size before inject

关键词： Physical simulation Deformable gel particle Breakage Particle size Residual resistance coefficient

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Cooperative activation of sodium channels for downgrading the energy efficiency in neuronal information processing

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Chinese Physics B 2024年第5期33卷 758-763页

作者：严浩然颜家琦俞连春邵玉峰 School of Physical Science and Technology Lanzhou Center for Theoretical PhysicsLanzhou UniversityLanzhou 730000China key laboratory of Theoretical Physics of Gansu Province and Key Laboratory of Quantum Theory and Applications of MoELanzhou UniversityLanzhou 730000China Department of Neuroscience AnatomyHistologyand EmbryologyKey Laboratory of Preclinical Study for New Drugs of Gansu ProvinceSchool of Basic Medical SciencesLanzhou UniversityLanzhou 730000China

The Hodgkin–Huxley model assumes independent ion channel activation,although mutual interactions are common in biological *** raises the problem why neurons would favor independent over cooperative channel *** this study,we evaluate how cooperative activation of sodium channels affects the neuron’s information processing and energy *** of the stochastic Hodgkin–Huxley model with cooperative activation of sodium channels show that,while cooperative activation enhances neuronal information processing capacity,it greatly increases the neuron’s energy *** a result,cooperative activation of sodium channel degrades the energy efficiency for neuronal information *** discovery improves our understanding of the design principles for neural systems,and may provide insights into future designs of the neuromorphic computing devices as well as systematic understanding of pathological mechanisms for neural diseases.

关键词： energy efficiency ion channel noise action potential generation neuronal dynamics

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The Boundary Element Method for Ordinary State-Based Peridynamics

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2807-2834页

作者： Xue Liang Linjuan Wang State key laboratory for Turbulence and complex systems Department of Mechanics and Engineering ScienceCollege of EngineeringPeking UniversityBeijing100871China CAPT-HEDPS and IFSA Collaborative Innovation Center of MoECollege of EngineeringPeking UniversityBeijing100871China School of Astronautics Beihang UniversityBeijing100191China

The peridynamics(PD),as a promising nonlocal continuum mechanics theory,shines in solving discontinuous *** to now,various numerical methods,such as the peridynamic mesh-free particlemethod(PD-MPM),peridynamic finite element method(PD-FEM),and peridynamic boundary element method(PD-BEM),have been ***-BEM,in particular,outperforms other methods by eliminating spurious boundary softening,efficiently handling infinite problems,and ensuring high computational ***,the existing PD-BEM is constructed exclusively for bond-based peridynamics(BBPD)with fixed Poisson’s ratio,limiting its applicability to crack propagation problems and scenarios involving infinite or semi-infinite *** this paper,we address these limitations by introducing the boundary element method(BEM)for ordinary state-based peridynamics(OSPD-BEM).Additionally,we present a crack propagationmodel embeddedwithin the framework ofOSPD-BEM to simulate crack *** validate the effectiveness of OSPD-BEM,we conduct four numerical examples:deformation under uniaxial loading,crack initiation in a double-notched specimen,wedge-splitting test,and threepoint bending *** results demonstrate the accuracy and efficiency of OSPD-BEM,highlighting its capability to successfully eliminate spurious boundary softening phenomena under varying Poisson’s ***,OSPDBEMsignificantly reduces computational time and exhibits greater consistencywith experimental results compared to PD-MPM.

关键词： Ordinary state-based peridynamics boundary element method crack propagation fracture toughness

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Hole cleaning evaluation and installation spacing optimization of cuttings bed remover in extended-reach drilling

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Petroleum Science 2024年第3期21卷 2005-2022页

作者： Shuo Peng Wen-Jun Huang De-Li Gao moe key laboratory of Petroleum Engineering China University of Petroleum-BeijingBeijing102249China State key laboratory of Petroleum Resources and Engineering China University of Petroleum-BeijingBeijing102249China

In extended-reach or long-horizontal drilling,cuttings usually deposit at the bottom of the *** cuttings accumulate to a certain thickness,complex problems such as excessive torque and drag,tubing buckling,and pipe stuck probably occur,which results in a lot of non-productive time and remedial *** bed remover can efficiently destroy deposited cuttings in time through hydraulic and mechanical stirring *** paper aims to build a method for hole cleaning evaluation and installation spacing optimization of cuttings bed remover to improve the wellbore cleaning ***,a Computational Fluid Dynamics approach with Eulerian—Eulerian multiphase model was utilized to investigate the mechanism of cuttings transportation,and a new type of cuttings bed remover was ***,an evaluation method of hole cleaning effect of remover was *** that,the effects of several drilling parameters on hole cleaning including flow rate of drilling fluid,rotational speed of drillpipe,rate of penetration,wellbore size,rheological property of drilling fluid,and remover eccentricity on the performance of cuttings bed remover were *** results demonstrate that the new type of remover with streamline blade performs better than conventional *** efficiency of hole cleaning is greatly improved by increasing the rotational speed of drillpipe,flow rate of drilling fluid,remover eccentricity,and 6 rpm Fann dial reading for drilling *** higher rate of penetration and large wellbore size result in worse hole *** findings can serve as an important guide for the structure optimization design of cuttings bed remover and installation spacing of removers.

关键词： Extended-reach drlling Drilling hydraulics Cuttings transport Hole cleaning Cuttings bed remover

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Localization of q-form fields on a de Sitter brane in chameleon gravity

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Frontiers of physics 2024年第3期19卷 11-18页

作者： Yi Zhong Tao-Tao Sui School of Physics and Electronics Science Hunan UniversityChangsha 410082China Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of MoELanzhou UniversityLanzhou 730000China College of Physics Nanjing University of Aeronautics and AstronauticsNanjing 211106China

Recently,it was found that the vector field can be naturally localized on the thick brane in chameleon *** this work,we extend this study to encompass de Sitter brane *** focus on the localization of q-form *** scalar and vector fields can be localized on the de Sitter brane,while the KR field cannot be *** condition for localization of the scalar and vector fields is ***,we investigate the localization characteristics in two examples with given conformal factor b(ϕ).In the first case,the effective potentials and KK modes of the matter fields are obtained asymmetric even though the de Sitter brane has Z2 *** the second case,volcano-like effective potentials are generated in the de Sitter brane model.

关键词： brane q-form field chameleon gravity

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Experimental and numerical investigation of the flexural performance of channel steel-bolt joint for prefabricated subway stations

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Frontiers of Structural and Civil Engineering 2024年第6期18卷 918-935页

作者： Lei WANG Shengyang ZHOU Xiangsheng CHEN Xian LIU Shuya LIU Dong SU Shouchao JIANG Qikai ZHU Haoyu YAO College of Civil and transportation Engineering Shenzhen UniversityShenzhen 518060China key laboratory of Coastal urban Resilient Infrastructures(moe) Shenzhen UniversityShenzhen 518061China Shenzhen key laboratory of Green Efficient and Intelligent Construction of Underground Metro StationShenzhen UniversityShenzhen 518061China College of Civil Engineering Tongji UniversityShanghai 200092China Shenzhen Municipal Design&Research Co. Ltd.Shenzhen 518029China Shenzhen Metro Group Co. Ltd.Shenzhen 518026China

Flexural performance of joints is critical for prefabricated *** study presents a novel channel steel-bolt(CB)joint for prefabricated subway ***-scale tests are carried out to investigate the flexural behavior of the CB joint under the design loads of the test-case *** addition,a three dimensional(3D)finite element(FE)model of the CB joint is established,incorporating viscous contact to simulate the bonding and detachment behaviors of the interface between channel steel and *** on the 3D FE model,the study examines the flexural bearing mechanism and influencing factors for the flexural performance of the CB *** results indicate that the flexural behavior of the CB joint exhibits significant nonlinear characteristics,which can be divided into four *** illustrate the piecewise linearity of the bending moment-rotational angle curve,a four-stage simplified model is proposed,which is easily applicable in engineering *** study reveals that axial force can enhance the flexural capacity of the CB joint,while the preload of the bolt has a negligible *** flexural capacity of the CB joint is approximate twice the value of the designed bending moment,demonstrating that the joint is suitable for the test-case station.

关键词： channel steel-bolt joint flexural performance full-scale test numerical simulation prefabricated subway station

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Geometric and defects engineering collaboration for enhanced cascade enzymatic nanoreactors

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Nano Research 2024年第4期17卷 2451-2461页

作者： Zhichao Yu Ruijin Zeng Hexiang Gong Yuan Gao Shuyun Chen Yunsen Wang Dianping Tang key laboratory for Analytical Science of Food Safety and Biology(moe&Fujian Province) Department of ChemistryFuzhou UniversityFuzhou 350108China

Highly evolved multi-enzyme cascade catalytic reactions in organisms facilitate rapid transfer of substrates and efficient conversion of intermediates in the catalytic unit,thus rationalizing their efficient *** this study,pore-ordered mesoporous single-atom(Fe)nitrogen-doped carbon nanoreactors(Mp-Fe-CN)were designed,in which a reasonable pore size was designed as a natural enzyme trap coupled to a simulated enzyme center.A polarity-mediated strategy was developed to obtain atomically dispersed nanoporous substrates,with the finding that polarity-guided engineering of the nitrogen-ligand environment and vacancy cluster defects clearly affects nanoporous activity,accompanied by appreciable mesoporous pore size *** active center and distal N atom coordination of Fe-N_(4) affect the catalytic process of the nanozyme exposed by density functional theory(DFT),determining the contribution of hybridized orbitals to electron transfer and the decisive step.A cascade nanoreactor-based domain-limited sarcosine oxidase developed for non-invasive monitoring of sarcosine levels in urine for evaluation of potential prostate carcinogenesis as a proof of *** on the design of surface mesoporous channels of nanocatalytic units,a bridge was built for the interaction between nanozymes and natural enzymes to achieve cascade nanocatalysis of natural enzymatic products.

关键词： nanozyme single-atom catalyst bioreactor cascade catalysis non-Invasive sensing

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