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Science China Mathematics 2024年第4期67卷 919-950页

作者： Xiaoqing Chi hui zhang Xiaoyun Jiang School of Mathematics and Statistics Shandong UniversityWeihai 264209China School of Mathematics Shandong UniversityJinan 250100China

In this paper,we first establish a new fractional magnetohydrodynamic(MHD)coupled flow and heat transfer model for a generalized second-grade *** coupled model consists of a fractional momentum equation and a heat conduction equation with a generalized form of Fourier *** second-order fractional backward difference formula is applied to the temporal discretization and the Legendre spectral method is used for the spatial *** fully discrete scheme is proved to be stable and convergent with an accuracy of O(τ^(2)+N-r),whereτis the time step-size and N is the polynomial *** reduce the memory requirements and computational cost,a fast method is developed,which is based on a globally uniform approximation of the trapezoidal rule for integrals on the real *** strict convergence of the numerical scheme with this fast method is *** present the results of several numerical experiments to verify the effectiveness of the proposed ***,we simulate the unsteady fractional MHD flow and heat transfer of the generalized second-grade fluid through a porous *** effects of the relevant parameters on the velocity and temperature are presented and analyzed in detail.

关键词： fractional MHD coupled flow and heat transfer model generalized second-grade fuid fast method convergence analysis numerical simulation

Super-high bed sintering for iron ores:problems ascertainment

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Journal of Iron and Steel Research(International) 2024年第5期31卷 1063-1070页

作者： Liang-ping Xu hui-bo Liu Yu-chao Zhao qiang Zhong Zhong-lin Dong Guang-hui Li Tao Jiang School of Minerals Processing and Bioengineering Central South UniversityChangsha410083HunanChina

Super-high bed sintering process is an important development direction of iron ore sintering for its lower emission and higher ***,there is a lack of deep understanding of the uneven quality of super-high bed sintering products,and the deterioration of reduction disintegration performance,the thickening of hearth layer and the reduction in energy-saving effect are perplexing enterprises and *** ascertain the problems of super-high bed sintering,ten sintering machines with the areas of 265,280,360,550 and 660 m^(2)and bed depth above 900 mm were sampled and *** results showed that problems were mainly shown in the unevenness of chemical composition,macrostructure,mechanical strength and metallurgical *** chemical composition exhibits severe segregation in both horizontal and vertical directions,with basicity segregation reaching as high as *** uneven macrostructure of sinter is reflected in a 10%difference in porosity and mechanical strength increase in 16%–19%along the vertical *** reducibility and reduction disintegration performance gradually deteriorate along the bed depth,with a difference of 10.5%in reducibility and 7.3%in RDI−0.5 mm(reduction disintegration index of sinter with size smaller than 0.5 mm).

关键词： Super-high bed sintering Uneven sinter performance Segregation Agglomeration Iron ore

Distributed Source-Load-Storage Cooperative Low-Carbon Scheduling Strategy Considering Vehicle-to-Grid Aggregators

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 440-453页

作者： Xiao Xu Ziwen Qiu Teng zhang hui Gao School of Automation Nanjing University of Posts and TelecommunicationsNanjing210023China

The vehicle-to-grid(V2G)technology enables the bidirectional power flow between electric vehicle(EV)batteries and the power grid,making EV-based mobile energy storage an appealing supplement to stationary energy storage ***,the stochastic and volatile charging behaviors pose a challenge for EV fleets to engage directly in multi-agent *** unlock the scheduling potential of EVs,this paper proposes a source-load-storage cooperative low-carbon scheduling strategy considering V2G *** uncertainty of EV charging patterns is managed through a rolling-horizon control framework,where the scheduling and control horizons are adaptively adjusted according to the availability periods of ***,a Minkowski-sum based aggregation method is employed to evaluate the scheduling potential of aggregated EV fleets within a given scheduling *** method effectively reduces the variable dimension while preserving the charging and discharging constraints of individual ***,a Nash bargaining based cooperative scheduling model involving a distribution system operator(DSO),an EV aggregator(EVA),and a load aggregator(LA)is established to maximize the social welfare and improve the low-carbon performance of the *** model is solved by the alternating direction method of multipliers(ADMM)algorithm in a distributed manner,with privacy of participants fully *** proposed strategy is proven to achieve the objective of low-carbon economic operation.

关键词： Electric vehicle(EV) low-carbon scheduling mobile storage system Nash bargaining power flexibility alternating direction method of multipliers(ADMM).

Atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering correction

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Nuclear Science and Techniques 2024年第3期35卷 40-52页

作者： Ding-Han Zhu Xiong zhang Xiao-qiang Li Peng Li Yan-Bin Wang Shuang zhang State Key Laboratory of NBC Protection for Civilian Beijing 102205China

In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such *** pulsed X-rays can be captured using a satellite-borne X-ray detector following atmospheric *** quantitatively analyze the effects of different satellite detection altitudes,burst heights,and transmission angles on the physical processes of X-ray transport and energy fluence,we developed an atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering *** proposed method is an improvement over the traditional analytical method that only computes direct-transmission *** traditional analytical method exhibits a maximum relative error of 67.79% compared with the Monte Carlo *** improved method reduces this error to within 10% under the same conditions,even reaching 1% in certain ***,its computation time is 48,000 times faster than that of the Monte Carlo *** results have important theoretical significance and engineering application value for designing satellite-borne nuclear detonation pulsed X-ray detectors,inverting nuclear detonation source terms,and assessing ionospheric effects.

关键词： High-altitude nuclear detonation Atmospheric transmission Pulsed X-rays Scattering correction Analytical method Monte Carlo method

Confinement of ionomer for electrocatalytic CO2 reduction reaction via efficient mass transfer pathways

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National Science Review 2024年第2期11卷 168-176页

作者： Xiaowei Du Peng zhang Gong zhang hui Gao Lili zhang Mengmeng zhang Tuo Wang Jinlong Gong School of Chemical Engineering and Technology Key Laboratory for Green Chemical Technology of the Ministry of Education Tianjin University Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) National Industry-Education Platform of Energy Storage Tianjin University Joint School of the National University of Singapore and Tianjin University International Campus of Tianjin University Haihe Laboratory of Sustainable Chemical Transformations

Gas diffusion electrodes（GDEs） mediate the transport of reactants, products and electrons for the electrocatalytic CO2reduction reaction（CO2RR） in membrane electrode assemblies. The random distribution of ionomer, added by the traditional physical mixing method, in the catalyst layer of GDEs affects the transport of ions and CO2. Such a phenomenon results in elevated cell voltage and decaying selectivity at high current densities. This paper describes a pre-confinement method to construct GDEs with homogeneously distributed ionomer, which enhances mass transfer locally at the active centers. The optimized GDE exhibited comparatively low cell voltages and high CO Faradaic efficiencies（FE > 90%） at a wide range of current densities. It can also operate stably for over 220 h with the cell voltage staying almost unchanged. This good performance can be preserved even with diluted CO2feeds, which is essential for pursuing a high single-pass conversion rate. This study provides a new approach to building efficient mass transfer pathways for ions and reactants in GDEs to promote the electrocatalytic CO2RR for practical applications.

关键词： CO2 electroreduction gas diffusion electrode mass transfer ionomer Ag catalyst

Analytical Models of on-Chip Hardware Trojan Detection Based on Radiated Emission Characteristics

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Chinese Journal of Electronics 2024年第2期33卷 385-392页

作者： Fan zhang Dongrong zhang qiang REN Aixin CHEN Donglin SU School of Electronics and Information Engineering Beihang University Zhongguancun Laboratory The Research Institute for Frontier Science Beihang University

Since many third parties involved in integrated circuit(IC) manufacturing, hardware Trojans malicious implantation have become a threat to the IC industry. Therefore, varieties of reliable hardware Trojan detection methods are needed. Since electromagnetic radiation is an inherent phenomenon of electronic devices, there are significant differences in the electromagnetic radiated characteristics for circuits with different structures and operating states. In this paper, a novel hardware Trojan detection method is proposed, which considers the electromagnetic radiation differences caused by hardware Trojan implantation. Experiments of detecting hardware Trojan in field programmable gate arrays show that the proposed method can effectively distinguish the ICs with Trojan from the ones without Trojan by the radiated emission.

关键词： Electromagnetic radiation Propagation losses Hardware System-on-chip Registers Manufacturing Trojan horses

Sarcopenia adversely impacts clinical outcomes in patients undergoing pancreaticoduodenectomy: A systematic review and meta-analysis

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World Journal of Gastrointestinal Surgery 2024年第6期16卷 1857-1870页

作者： Qi-hui zhang Jin-Dong Ma Yan-Min Lu Run-Nan zhang Zhong-Hua Zhao Ya-Tong Li qiang-Pu Chen Department of Clinical Nutrition Binzhou Medical University HospitalBinzhou 256603Shandong ProvinceChina Department of Hepatobiliary Surgery Binzhou Medical University HospitalBinzhou 256603Shandong ProvinceChina

BACKGROUND Sarcopenia is a syndrome marked by a gradual and widespread reduction in skeletal muscle mass and strength,as well as a decline in functional ability,which is associated with malnutrition,hormonal changes,chronic inflammation,distur-bance of intestinal flora,and exercise *** is a com-monly employed clinical intervention for conditions such as pancreatic head cancer,ampulla of Vater cancer,and cholangiocarcinoma,among others,with a notably high rate of postoperative *** is frequent in patients undergoing ***,data regarding the effects of sarcopenia in patients undergoing pancreaticoduodenectomy(PD)are both limited and *** PubMed,Cochrane Library,Web of Science,and Embase databases were screened for studies published from the time of database inception to June 2023 that described the effects of sarcopenia on the outcomes and complications of *** researchers independently assessed the quality of the data extracted from the studies that met the inclusion ***-analysis using RevMan 5.3.5 and Stata 14.0 software was *** and funnel plots were used,respectively,to demonstrate the outcomes of the sarcopenia group vs the non-sarcopenia group after PD and to evaluate potential publication *** Sixteen studies encompassing 2381 patients were included in the *** patients in the sarcopenia group(n=833)had higher overall postoperative complication rates[odds ratio(OR)=3.42,95%confidence interval(CI):1.95-5.99,P<0.0001],higher Clavien-Dindo class≥III major complication rates(OR=1.41,95%CI:1.04-1.90,P=0.03),higher bacteremia rates(OR=4.46,95%CI:1.42-13.98,P=0.01),higher pneumonia rates(OR=2.10,95%CI:1.34-3.27,P=0.001),higher pancreatic fistula rates(OR=1.42,95%CI:1.12-1.79,P=0.003),longer hospital stays(OR=2.86,95%CI:0.44-5.28,P=0.02),higher mortality rates(OR=3.17,95%CI:1.55-6.50,P=0.002),and worse overall survival(hazard ratio=2.81,95%CI:1

关键词： Pancreaticoduodenectomy Sarcopenia Postoperative complications Length of stay Meta-analysis

Critical Role of Ethylene-Propylene Block Copolymer in Impact Polypropylene Copolymer

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Chinese Journal of Polymer Science 2024年第3期42卷 344-351,I0007页

作者： Yu-hui Tang Na zhang Wei Bao Wei Jiang Yuan Lin Zhao-hui Su State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Ethylene-propylene block copolymer(EbP) is a vital component in impact polypropylene copolymer(IPC), yet its distribution in the multiphase composite material and how it influences the phase structure and the mechanical properties are not well understood. In this work,four IPCs were investigated by atomic force microscopy-infrared(AFM-IR) to assess the phase compositions in situ, based on which in conjunction with the chain microstructure information obtained ex situ the distributions of the copolymer components were derived for each alloy. For the IPCs whose EbP comprises long P and long E segments, the EbP fraction was found to phase separate from the rubber and the PP matrix to form the cores of the disperse particles with the E-P segmented copolymer(EsP). In contrast, in the IPC with EbP composed of long P and short E segments, the EbP fraction formed an outer shell for the rubber particles with the cores comprising the EsP alone, and this IPC, containing a lower E comonomer content than its counterpart, exhibited both better impact resistance and higher flexural modulus. These results clarify how the chain structure of EbP governs the phase morphology in IPC, which in turn impacts the properties of the composite material.

关键词： Impact polypropylene copolymers AFM-IR Ethylene-propylene block copolymers Core-shell rubber particles

Lath-like phases formed at an extremely high temperature in a Mg-RE(RE=rare earth)-Al alloy

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Rare Metals 2024年第8期43卷 3937-3945页

作者： Bo Deng Shu-hui Lv qiang Yang Dong-Yue Zhao Jun-Yuan Fan Xin Qiu School of Materials Science and Engineering Changchun University of Science and Technology State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of Sciences Chongqing Research Institute Changchun University of Science and Technology

Thermal stable intermetallic particles are important for the heat resistance of magnesium（Mg）*** this work,many lath-like particles formed in α-Mg grains of a Mg-8Gd-3Sm-0.7Al casting alloy when heat-treated at 873 ***-resolution high-angle annular dark field scanning transmission electron microscopy（HAADF-STEM） characterizations indicate that most of them are Mg-containing Al2（Gd,Sm）,with the atomic ratio of Mg:Al:（Gd,Sm） being ～1:1:1;a small part of them with relatively wider thickness are long-period stacking ordered（LPSO） phases simultaneously containing both 14H and 18R *** followed common orientation relationships with Mg matrix as those reported in previous *** addition,many Mg laths were observed in the primary blocky Al2（Gd,Sm） phase at grain boundaries,where the atomic ratio of Al:（Gd,Sm） in the Al2（Gd,Sm） matrix was 2:***,density functional theory（DFT） calculations illustrated the detail structure of the re-constructed Mg/Al2RE interface and simultaneously deduced the underlying reason for the re-dissolution of the newly formed Mg-containing Al2（Gd,Sm） plates in α-Mg matrix.

关键词： Magnesium alloy HAADF-STEM Microstructures Intermetallic particles Orientation relationships Interfaces

Insights into in-situ imbibition behavior of fracturing fluid in propped shale fractures based on nuclear magnetic resonance:A case study from Longmaxi Formation shale,Sichuan Basin,China

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Petroleum Science 2024年第1期21卷 410-429页

作者： Jing-Jing Guo Kai-Xiang Di Lie-hui zhang Yu-Long Zhao hui-Ying Tang Rui-Han zhang Ye Tian National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina

Shale gas is an important component of unconventional oil and gas *** the imbibition behavior is helpful to optimize flowback parameters and enhance gas *** imbibition studies have focused on shale matrix,and the pressure conditions discussed were mostly *** initial imbibition behavior begins from propped fractures to matrix,but there are few studies working on explaining the imbibition behavior in propped fractures or the phenomenon of many shale wells exhibit higher productivity after a“soaking”***,propped fracture samples were designed for imbibition and migration *** order to accurately study the mechanism and main influencing factors of fracturing fluid imbibition and migration in propped and unpropped shale fractures under high temperature and high pressure,a series of experiments based on nuclear magnetic resonance(NMR)were carried *** showed that NMR T_(2) spectra of all samples exhibited a bimodal *** final imbibition volume of fracturing fluid was positively related to pressure and fracture *** imbibition effect of fracturing fluid was more evident in matrix pores under high *** the migration during soaking stage,the fracturing fluid gradually migrated from large pores to small pores and gradually displaced the shale gas from the matrix,thus allowing the water blocking in propped fractures to self-unlock to some *** permeability decreased in the imbibition stage,while it recovered in the migration stage to some extent.

关键词： Forced imbibition Migration Soaking NMR T_(2)spectra Propped fracture Permeability recovery