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Fracture sealing performance of granular lost circulation materials at elevated temperature:A theoretical and coupled CFD-DEM simulation study

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Petroleum Science 2024年第1期21卷 567-581页

作者： Chong lin Qi-Cong Xu Lie-Xiang Han Gao Li Hai He Hong-ling Zhou ji-Ping She CCDC Drilling&Production Technology Research Institute Guanghan618300SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina College of Materials Science and Engineering Chongqing UniversityChongqing400044China State Key Lab of Oil and Gas Reservoir Geology and Exploitation(Chengdu University of Technology) Chengdu610059SichuanChina College of Energy Chengdu University of TechnologyChengdu610059SichuanChina

Lost circulation is a common downhole problem of drilling in geothermal and high-temperature,high-pressure(HTHP)*** circulation material(LCM)is a regular preventive and remedial measure for lost ***,conventional LCMs seem ineffective in high-temperature *** may be due to the changes in the mechanical properties of LCMs and their sealing performance under high-temperature *** understand how high temperature affects the fracture sealing performance of LCMs,we developed a coupled computational fluid dynamics-discrete element method(CFD-DEM)model to simulate the behavior of granular LCMs in *** summarized the literature on the effects of high temperature on the mechanical properties of LCMs and the rheological properties of drilling *** conducted sensitivity analyses to investigate how changing LCM slurry properties affected the fracture sealing efficiency at increasing *** results show that high temperature reduces the size,strength,and friction coefficient of LCMs as well as the drilling fluid ***,softer,and less frictional LCM particles have lower bridging probability and slower bridging *** particles tend to form dual-particle bridges rather than single-particle *** result in a deeper,tighter,but unstable sealing *** drilling fluid viscosity leads to faster and shallower sealing zones.

关键词： Geothermal well drilling HTHP formationLost circulation material CFD-DEM Fracture sealing

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Experimental and numerical investigation of two blended blade and endwall configurations

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Chinese Journal of Aeronautics 2024年第9期37卷 150-163页

作者： Tongtong MENG Xin LI ling ZHOU Lucheng ji Institute for Aero Engine Tsinghua UniversityBeijing 100084China Schoolof Aerospace Engineering Bejing Institute of TechnologyBeijing 0081China

The Blended Blade and Endwall(BBEW)technique has proven to be effective in control-ling the intersection of boundary layer in corner region of the compressor *** this study,the experiment and analysis of two different BBEW designs are ***,based on a linear cas-cade with 0.7 Mach number inflow,two different configurations,BBEW 1 and BBEW 2,are well ***,according to the experimental result,control effects of these two BBEW configu-rations are validated and compared subsequently under various working *** results demonstrate a reduction in total pressure loss of 12.8%and 29%at the design point for BBEW 1 and BBEW 2,***,the BBEW technique proves effective in suppressing the development of the boundary layer and preventing corner *** by detailed numerical analysis,improvements around the corner region,especially for the boundary layer,are extracted to show the mechanisms and distinctions between the two *** results indicate that BBEW 1 significantly restrains the development of boundary layer before separation occurs,while BBEW 2 directly controls the strength and scale of the corner separation.

关键词： Aerodynamic Computational fluid dynamic Experiment Corner separation Blended Blade and Endwall(BBEW)

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Semi-derived Ringel-Hall algebras and Hall algebras of odd-periodic relative derived categories

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Science China Mathematics 2024年第8期67卷 1735-1760页

作者： ji lin Liangang Peng Department of Mathematics and Statistics Fuyang Normal UniversityFuyang 236037China School of Mathematics Sichuan UniversityChengdu 610064China

Let t be a positive integer and A be a hereditary abelian category satisfying some finiteness *** define the semi-derived Ringel-Hall algebra of A from the category C_(Z/t)(A)of Z/t-graded complexes and obtain a natural basis of the semi-derived Ringel-Hall ***,we describe the semiderived Ringel-Hall algebra by the generators and defining *** particular,if t is an odd integer,we show an embedding of the derived Hall algebra of the odd-periodic relative derived category in the extended semi-derived Ringel-Hall algebra.

关键词： hereditary abelian categories the categories of Z/t-graded complexes semi-derived Ringel-Hall algebras derived Hall algebras

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Design and application of copper/lithium composite anodes for advanced lithium metal batteries

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Rare Metals 2024年第3期43卷 942-970页

作者： Bin Zhang ji-Ping Ma Yang Zhao Tong Li jin-lin Yang Zhan-ling Zhang Shi-Zhong Wei Guang-Min Zhou School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471003China Shenzhen Geim Graphene Center Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China School of Physical and Mathematical Sciences Nanyang Technological UniversitySingapore 637371Singapore Shenzhen Geim Graphene Center Tsinghua-Berkeley Shenzhen InstituteTsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

Lithium(Li)is a promising candidate for nextgeneration battery anode due to its high theoretical specific capacity and low reduction ***,safety issues derived from the uncontrolled growth of Li dendrite and huge volume change of Li hinder its practical application.C onstructing dendrite-free composite Li anodes can significantly alleviate the above ***(Cu)-based materials have bee n widely used as substrates of the composite electrodes due to their chemical stability,excellent conductivity,and good mechanical ***/lithium(Cu/Li)composite anodes significantly regulate the local current density and decrease Li nucleation overp otential,realizing the uniform and dendrite-free Li *** this review,Cu/Li composite methods including electrodeposition,melting infusion,and mechanical rolling are systematically summarized and ***,design strategies of Cu-based current collectors for high performance Cu/Li composite anodes are *** challenges and future development for Cu/Li composite anodes are presented and *** hope that this review can provide a comprehensive understanding of Cu/Li composite methods of the latest development of Li metal anode and stimulate more research in the future.

关键词： Lithium metal batteries Cu/Li composite anode Electrodeposition Thermal melting infusion Mechanical rolling

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Deep reinforcement learning based active surge control for aeroengine compressors

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Chinese Journal of Aeronautics 2024年第7期37卷 418-438页

作者： Xinglong ZHANG Zhonglin lin Runmin ji Tianhong ZHANG College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China

This study proposes an active surge control method based on deep reinforcement learning to ensure the stability of compressors when adhering to the pressure rise command across the wide operating range of an ***,the study establishes the compressor dynamic model with uncertainties,disturbances,and Close-Coupled Valve(CCV)actuator *** upon this foundation,a Partially Observable Markov Decision Process(POMDP)is defined to facilitate active surge *** address the issue of unobservability,a nonlinear state observer is designed using a finite-time high-order sliding ***,an Improved Soft Actor-Critic(ISAC)algorithm is developed,incorporating prioritized experience replay and adaptive temperature parameter techniques,to strike a balance between exploration and convergence during *** addition,reasonable observation variables,error-segmented reward functions,and random initialization of model parameters are employed to enhance the robustness and generalization ***,to assess the effectiveness of the proposed method,numerical simulations are conducted,and it is compared with the fuzzy adaptive backstepping method and Second-Order Sliding Mode Control(SOSMC)*** simulation results demonstrate that the deep reinforcement learning based controller outperforms other methods in both tracking accuracy and ***,the proposed active surge controller can effectively ensure stable operation of compressors in the high-pressure-ratio and high-efficiency region.

关键词： Aeroengine surge Active surge control Moore-Greitzer model Deep reinforcement learning Soft actor-critic Nonlinear observer

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Machine learning model based on non-convex penalized huberized-SVM

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Journal of Electronic Science and Technology 2024年第1期22卷 81-94页

作者： Peng Wang ji Guo lin-Feng Li School of Finance and Economics Xizang Minzu UniversityXianyang712082China Research Center for Quality Development of Xizang Special Industries Xianyang712082China School of Computer Science and Technology Xinjiang UniversityUrumqi830017China

The support vector machine(SVM)is a classical machine learning *** the hinge loss and least absolute shrinkage and selection operator(LASSO)penalty are usually used in traditional ***,the hinge loss is not differentiable,and the LASSO penalty does not have the Oracle *** this paper,the huberized loss is combined with non-convex penalties to obtain a model that has the advantages of both the computational simplicity and the Oracle property,contributing to higher accuracy than traditional *** is experimentally demonstrated that the two non-convex huberized-SVM methods,smoothly clipped absolute deviation huberized-SVM(SCAD-HSVM)and minimax concave penalty huberized-SVM(MCP-HSVM),outperform the traditional SVM method in terms of the prediction accuracy and classifier *** are also superior in terms of variable selection,especially when there is a high linear correlation between the *** they are applied to the prediction of listed companies,the variables that can affect and predict financial distress are accurately filtered *** all the indicators,the indicators per share have the greatest influence while those of solvency have the weakest *** companies can assess the financial situation with the indicators screened by our algorithm and make an early warning of their possible financial distress in advance with higher precision.

关键词： Huberized loss Machine learning Non-convex penalties Support vector machine(SVM)

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Investigating effect of coke porosity on blast furnace performance based on multi-physical fields

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Journal of Iron and Steel Research International 2024年第2期31卷 357-367页

作者： ji Chen Zhao Lei Zhe Yao Li Wang Qiang ling Ping Cui Anhui Province Key Laboratory of Coal Clean Conversion and High Valued Utilization School of Chemistry and Chemical EngineeringAnhui University of TechnologyMa’anshan243002AnhuiChina Shanxi Academy of Printing Technology Research Institute Co. Ltd.Xi’an710077ShaanxiChina

Reducing coke use is an effective measure to reduce carbon emission and energy consumption in the blast furnace(BF)***,BF is a high-temperature moving bed reactor,where complex physical transformations coupled with complicated reactions *** makes it challenging to investigate the factors determining BF performance with the conventional method.A multi-physical field coupling mathematical model of BF was thus developed to describe its mass and heat transfer as well as its intrinsic ***,the proposed model was validated with the production *** coupling conditions,influences of dominating reactions on BF performance(temperature distribution,gas distribution,iron formation reaction,and direct reduction degree)were *** results indicated that coke combustion,indirect reduction,and direct reduction of iron ore mainly took place nearby the shaft tuyere,cohesive zone,and dripping zone,***,the rate of coke solution loss reaction was increased with the rising coke porosity in the cohesive *** the effect of coke porosity on the efficiency and stability of BF,the coke porosity of 0.42 was regarded as a reasonable value.

关键词： Blast furnace Mathematical model Multi-physical field Simulation Coke porosity

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Postpartum depression and partner support during the period of lactation:Correlation research and its influencing factors

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World Journal of Psychiatry 2024年第1期14卷 119-127页

作者： ji-Ming Ruan ling-Juan Wu Department of Obstetrics and Gynecology Huzhou Maternity and Child Health Care HospitalHuzhou 313000Zhejiang ProvinceChina

BACKGROUND Postpartum depression(PPD)not only affects the psychological and physiological aspects of maternal health but can also affect neonatal growth and *** who are in close contact with parturient women play a key role in communication and emotional *** study explores the PPD support relationship with partners and its influencing factors,which is believed to establish psychological well-being and improve maternal partner *** To explore the correlation between PPD and partner support during breastfeeding and its influencing *** Convenience sampling was used to select lactating women(200 women)who underwent postpartum examinations at the Huzhou Maternity and Child Health Care Hospital from July 2022 to December 2022.A cross-sectional survey was conducted on the basic information(general information questionnaire),depression level[edinburgh postnatal depression scale(EPDS)],and partner support score[dyadic coping inventory(DCI)]of the selected ***’s correlation analysis was used to analyze the correlation between PPD and DCI in lactating *** affecting PPD levels during lactation were analyzed using multiple linear *** The total average score of EPDS in 200 lactating women was(9.52±1.53),and the total average score of DCI was(115.78±14.90).Dividing the EPDS,the dimension scores were:emotional loss(1.91±0.52),anxiety(3.84±1.05),and depression(3.76±0.96).Each dimension of the DCI was subdivided into:Pressure communication(26.79±6.71),mutual support(39.76±9.63),negative support(24.97±6.68),agent support(6.87±1.92),and joint support(17.39±4.19).Pearson’s correlation analysis demonstrated that the total mean score and individual dimension scores of EPDS during breastfeeding were inversely correlated with the total score of partner support,stress communication,mutual support,and cosupport(P<0.05).The total mean score of the EPDS and its dimensions were positively correlated with negative

关键词： Lactation period Puerpera Postpartum depression Partner support Correlation

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Catalytically generated noncovalent ammonium dienolate:a versatile platform for the development of organocatalytic asymmetric cascade reactions

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Science China Chemistry 2024年第8期67卷 2524-2546页

作者： Jun-Bing lin Dong-Sheng ji Peng-Fei Xu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China Shaanxi Key Laboratory of Chemical Reaction Engineering College of Chemistry and Chemical EngineeringYan’an UniversityYan’an 716000China

Organocatalytic cascade reactions represent a powerful strategy for the rapid construction of complex chiral molecules with multiple stereocenters from simple substrates under mild conditions. The intriguing structural feature and diverse reactivity of catalytically generated dienolate species render them competent and versatile intermediates for the development of practical and valuable cascade reactions. Over the past years, a plethora of innovative and pioneering noncovalent ammonium dienolatemediated cascade reactions have been designed and implemented under the catalysis of chiral organocatalysts, making dienolate activation a general, robust, and complementary method for the functionalization of unsaturated carbonyl compounds and related substances. This review illustrates the recent advances in organocatalytic noncovalent ammonium dienolate-mediated cascade reactions(mainly from 2010 to 2023), including the cascade transformations of ammonium dienolates directly generated from unsaturated ketone/aldehyde, ester/lactone/azlactone, amide/lactam/pyrazolone/oxindole, and alkylidene nitrile compounds. The contents are arranged based on the reaction types of the ammonium dienolates, with an emphasis on cascade 2,5-, 3,5-, and 4,5-difunctionalizations of these intermediates. Furthermore, other cascade reactions involving the 1,3-, 2,3-, and even more complex 3,4,5-reactivities of ammonium dienolates were also discussed. The reaction pathway, reaction stereoinduction, and synthetic applications of the ammonium dienolate-mediated cascade reactions were highlighted throughout the article. As a stimulating and ever-growing research area, the organocatalytic noncovalent ammonium dienolate-mediated cascade reactions are expected to continue demonstrating their magic power for constructing chiral targets in the future and further expanding the boundaries of asymmetric catalysis.

关键词： organocatalysis asymmetric catalysis ammonium dienolate cascade reaction difunctionalization

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Measurement and analysis of airtightness safeguard measures for typical ultra-low energy buildings

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Energy and Built Environment 2024年第3期5卷 348-363页

作者： Yongming ji lin Duanmu Songtao Hu School of Environmental and Municipal Engineering Qingdao University of TechnologyQingdaoShandong Province 266033China School of Civil Engineering Dalian University of TechnologyDalianLiaoning Province 116024China

Zero-energy buildings constitute an effective means of reducing urban carbon *** airtightness,a typical characteristic of zero-energy building,is closely related to the building’s air infiltration and has a signifi-cant impact on the performance of the building envelope,indoor air quality,building energy consumption,and efficient operation of air-conditioning ***,thus far,systematic developments in high-airtightness assurance technologies remain *** existing studies have tested the airtightness of buildings and typical building components;however,in-depth analyses into the formation of infiltration have not been ***-fore,for realizing zero-energy buildings,ensuring airtightness is an urgent problem that needs to be ***,in this study,based on several building airtightness measurement studies,the typical air leakage paths in buildings were summarized,and the causes of typical air leakage components in buildings were further analysed by tracing construction ***,targeted measures for airtightness in buildings were estab-lished and applied to practical ***,the resulting improved building airtightness was measured and the results show that the airtightness of the measured ultra-low energy consumption buildings ranges from 0.13 h^(−1)to 0.57 h^(−1),with a mean value of 0.32 h^(−1).The effectiveness of the airtightness safeguard measures was *** study serves as a basis for the assumption of the air leakage path distribution when simulating building air infiltration and also provides a design reference for improving the construction technologies and airtightness of buildings.

关键词： Carbon neutrality Airtightness Safeguard measures Ultra-low energy buildings

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