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Science China Mathematics 2024年

作者： Xinping gui Buyang Li Jilu wang Beijing Computational Science Research Center Department of Applied Mathematics The Hong Kong Polytechnic University School of Science Harbin Institute of Technology

A class of stochastic Besov spaces BpL2(Ω;H~α(O)), 1≤ p ≤∞ and α ∈ [-2, 2], is introduced to characterize the regularity of the noise in the semilinear stochastic heat equation du-△udt = f(u)dt + d W(t),under the following conditions for some α ∈(0, 1]:‖(∫t)0e~(-(t-s)A)dW(S)‖_(L2(Ω;L2(O)))≤Cta/2and ‖(∫t)0e~(-(t-s)A)dW(S)‖_(B~∞L2(Ω;H~α(O)))≤C The conditions above are shown to be satisfied by both trace-class noises(with α = 1) and one-dimensional space-time white noises(with α =1/2). The latter would fail to satisfy the conditions with α =1/2 if the stochastic Besov norm ∥·∥_(B~∞L2(Ω;H~α(O)))is replaced by the classical Sobolev norm ∥·∥_(L2(Ω;H~α(O))), and this often causes reduction of the convergence order in the numerical analysis of the semilinear stochastic heat equation. In this paper, the convergence of a modified exponential Euler method, with a spectral method for spatial discretization,is proved to have order α in both the time and space for possibly nonsmooth initial data in L4(Ω;H~β(O)) withβ >-1, by utilizing the real interpolation properties of the stochastic Besov spaces and a class of locally refined stepsizes to resolve the singularity of the solution at t = 0.

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Hard carbon for sodium storage:Mechanism and performance optimization

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Nano Research 2024年第7期17卷 6038-6057页

作者： Yongxin wang Meng Li yu Zhang Naiqing Zhang State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001China School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Due to the shortage of lithium resource reserves and the pressure of rising prices,sodium-ion batteries have regained the attention of the public,and shown great potential for application in the fields of grid energy storage and low-speed vehicles to achieve the purpose of complementing lithium-ion batteries,so it is imperative to promote the commercial application of sodiumion *** sodium-ion battery anode materials,hard carbon is the material most likely to be used ***,there is still much work to be done before its *** review provides a comprehensive overview of the current research status from the following three ***,the microstructure and sodium storage active sites of hard carbon are ***,the mechanism of sodium storage in hard carbon is investigated,which can be broadly categorized into four model,“insertion–filling”,“adsorption–insertion”,“adsorption–filling”,and“multistage”.Finally,from the perspective of improving the electrochemical performance of hard carbon,the performance improvement strategies proposed in recent years are *** with the performance of hard carbon commercial products of some enterprises,the future development goal of hard carbon is prospected,hoping that all sectors of society can work hard for this common goal.

关键词： sodium-ion battery hard carbon mechanism performance optimization

Design and Cryogenic Performance of a Hexapod Platform for a Large Ground-based Wide Field Survey Telescope

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Research in Astronomy and Astrophysics 2024年第1期24卷 178-187页

作者： Yang yu Xue-Wen wang yu Zhang Jia-Lin Sun Zhen-Bang Xu Jian-Li wang Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Chinese Academy of Sciences Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System Changchun 130033China University of Chinese Academy of Sciences Beijing 100049China

The thermal gradient is an important factor that causes degradation to the image quality of telescopes. In order to ensure the accurate alignment of the primary focus unit and the primary mirror, the hexapod platform(as a corrector) is investigated in this paper. First, a ground-based telescope with 2.5 m aperture and 3.5 deg field of view is described. The telescope is under construction, and it is expected to be finished in 2023. Second, the hexapod platform with flexure hinges utilized to adjust the primary focus unit is proposed, which is applied as a ***, the inverse kinematics of the platform is established and an open-loop control system is built based on ***, the cryogenic performance test for the hexapod platform is performed. The experimental results show that the resolution and repeatability of the translation for the hexapod platform can be achieved at the micrometer *** resolution and repeatability of the rotation can be achieved at the arc-second level. Therefore, the cryogenic performance of the hexapod platform can meet the optical imaging requirements of the wide-field ground-based telescope. The kinematic analysis and cryogenic performance tests in the paper provide a technical reference for the precise alignment of the primary focus unit and the primary mirror, which can improve the imaging quality of the telescope.

关键词： methods:miscellaneous space vehicles:instruments telescopes miscellaneous

Magnesium-containing pellet regulating blast furnace ferrous burden interaction:softening-melting behavior and mechanism

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Journal of Iron and Steel Research International 2024年第7期31卷 1623-1635页

作者： Li-ming Ma Jian-liang Zhang Yao-zu wang Xiao-yong Ma gui-lin wang Zhuo Li Hui-qing Jiang Zheng-jian Liu School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Intelligence Science and Technology University of Science and Technology BeijingBeijing 100083China Lingyuan Iron and Steel Group Co. Lingyuan 122500LiaoningChina

MgO participates in all stages of sintering,pelletizing,and blast furnace ironmaking,and synergistically optimizing the distribution of MgO in ferrous burden can effectively enhance the interaction within the ferrous burdens and optimize the softening-melting properties of the mixed ***-containing pellets mixed with low-MgO sinter or mixed with high-MgO sinter in the blast furnace ferrous burden structure have opposite softening-melting performance *** the structure of the ferrous burden is magnesium-containing pellets mixed with low-MgO sinter,the magnesium-containing pellets can enhance the interaction of the ferrous burden in the process of softening-melting,which can optimize the composition of the slag phase and improve the slag *** the structure of the ferrous burden is magnesium-containing pellets mixed with high-MgO sinter,the magnesium-containing pellets weaken the interaction of the ferrous burden in the process of softening-melting,increase the content of the high melting point solid-phase particles in the slag,lead to an increase in the viscosity of the slag and difficult separation of the slag and iron,and decrease the permeability of the charge ***,to ensure good permeability of the mixed burden,the following measures are suggested:optimizing the MgO distribution of the ferrous burden,reducing the MgO content of the sinter to 1.96 wt.%,increasing the MgO content of the pellets to 1.03-1.30 wt.%,controlling the MgO/Al_(2)O_(3) ratio of the mixed burden within 1.15-1.32,narrowing the position of the cohesive zone,and maintaining an S value(permeability index)of approximately 150 kPa℃.

关键词： Ironmaking Ferrous burden Softening-melting property Interaction Permeability Slag

Numerical investigation and modeling of sweep effects on inlet flow field of axial compressor cascades

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Chinese Journal of Aeronautics 2024年第2期37卷 296-308页

作者： Jiancheng ZHANG Donghai JIN Xingmin gui School of Energy and Power Engineering Beihang UniversityBeijing 100191China Jiangxi Research Institue of Beihang University Nanchang 330096China

Swept blades are widely utilized in transonic compressors/fans and provide high load,high through-flow,high efficiency,and adequate stall ***,there is limited quantitative research on the mechanism of the effect of swept blades on the flow field,resulting in a lack of direct quantitative guidance for the design and analysis of swept blades in fans/*** better understand this mechanism,this study employs a reduced-dimensional force equilibrium method to analyze more than 1500 swept cascades *** verify that circumferential fluctuation terms are responsible for inducing radial migration in the inlet airflow field of the swept blade,resulting in variations in the incidence angle and consequently leading to changes in the characteristics of the swept ***,a combination of simple functions and machine learning is utilized to model the circumferential fluctuation terms and quantify the sweep *** prediction accuracy of the model is high,with coefficient of determination greater than 0.95 on the test *** the model is applied in a meridional flow analysis program,the calculation accuracy of the program for the incidence angle is improved by 0.4°and 0.6°at the design and off-design conditions respectively,compensating for the program’s original ***,the model can also provide quantitative guidance for the design of swept blades,thereby reducing the number of design iterations and improving design efficiency.

关键词： Turbomachinery Sweep aerodynamics Quasi-3D method Incidence angle Circumferential fluctuation Machine learning

Organic interfacial engineering of gold nanowires for selective glycerol electrooxidation

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Chinese Chemical Letters 2024年第3期35卷 502-507页

作者： Zhe wang Qingling Hong Boqiang Miao Tianjiao wang yu Ding Pujun Jin Pei Chen yu Chen Key Laboratory of Macromolecular Science of Shaanxi Province Key Laboratory of Applied Surface and Colloid Chemistry(Ministry of Education)Shaanxi Key Laboratory for Advanced Energy DevicesSchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an 710062China

The selective electrochemical conversion of glycerol into value-added products is a green and sustainable strategy for the biomass *** this work,Au nanowires(Au-NW)modified with polyethyleneimine(PEI)molecule(Au-NW@PEI)is obtained by an up-bottom post-modification *** characterization,molecular dynamics simulation and density functional theory demonstrate that the loose-packed PEI monolayer firmly and uniformly distribute on the Au-NW surface due to the strong Au-N *** experiments and product analysis display that PEI modification significantly enhance the electro-activity of Au-NW for the glycerol electro-oxidation reaction(GEOR)due to the electronic ***,the steric hindrance and electrostatic effect of PEI layer make the optimizing adsorption of intermediates ***,the selectivity of C3 product glyceric acid over Au-NW@PEI is increased by nearly 20%.The work thus indicates that the rational design of metal-organic interface can effectively elevate the electro-activity and selectivity of Au nanostructures,which may have wide application in biomass development.

关键词： Glycerol electrooxidation reaction Organic interface engineering Gold-based nanomaterials Electrocatalysis Selectivity

Jejunal sarcomatoid carcinoma:A case report and review of literature

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World Journal of Gastrointestinal Oncology 2024年第8期16卷 3723-3731页

作者： Qian Feng Wei yu Jing-Hui Feng Qiao Huang gui-Xiang Xiao The First College of Clinical Medical Science China Three Gorges UniversityYichang 443000Hubei ProvinceChina Department of Oncology Yichang Central People's HospitalYichang 443000Hubei ProvinceChina Institute of Pathology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022Hubei ProvinceChina

BACKGROUND Sarcomatoid carcinoma(SCA)of the jejunum is a rare and aggressive neoplasm affecting the smooth muscle cells of the *** study presents a recent case of jejunal SCA,detailing its diagnosis and treatment,thereby providing a reference for clinical *** SUMMARY A 65-year-old male presented to Yichang Central People's Hospital with a chief complaint of hemorrhoids.A computed tomography(CT)scan incidentally revealed multiple abnormal signals in the *** positron emission tomography/CT at Wuhan Union Hospital indicated malignant tumor progression,with a primary duodenal tumor and multiple metastases in the upper left ***,a large tumor was identified on the *** and immunohistochemical analyses of the resected specimen confirmed the diagnosis of jejunal *** patient received a combination therapy of sintilimab,nanoparticle albumin-bound paclitaxel,and ***-up imaging demonstrated significant reduction of hepatic and peritoneal *** patient has remained stable for over one year *** This case suggests that chemotherapy,immunotherapy,plus targeted therapy may represent an optimal treatment for intestinal SCA,meriting further investigation.

关键词： Jejunal sarcomatoid carcinoma Targeted therapy Immunotherapy Chemotherapy Case report

Study on Effectiveness of Solitary-Wave-Like Form Based on Overtopping Data from Irregular Wave Tests

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China Ocean Engineering 2024年第4期38卷 701-710页

作者： LI Xiao-liang Huang gui-biao School of Naval Architecture&Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

The previous study conducted by Li(2022)demonstrates that the Goda graph can be adequately represented by a solitary-wave-like form across the entire range of relative water depth,with the exception of the extremely shallow ***,it remains uncertain whether this form is equally effective when applied to test data generated by irregular waves,as the Goda graph was initially developed based on overtopping data from regular wave ***,it is unclear whether this form is suitable for formulating overtopping discharge at composite vertical *** order to address these questions,a 2D overtopping experiment was conducted,incorporating both simple and composite types of vertical walls,with various relative water depths across the entire range,excluding the extremely shallow zone.A novel analysis procedure was developed,which proved to be highly productive and can be considered a general method for data ***,the study yielded two conclusions:(1)the solitary-wave-like form is remarkably effective in formulating overtopping test data generated by irregular waves,regardless of whether the vertical wall is simple or composite,and(2)the resulting formulas exhibit definitely better performance compared with existing formulas.

关键词： solitary-wave-like form overtopping discharge overtopping formula vertical wall

Robust Feedback Set Stabilization of Logic Networks with State-Dependent Uncertain Switching and Control Constraints

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Journal of Systems Science & Complexity 2024年第2期37卷 629-646页

作者： DAI Chaoqun GUO yuqian gui Weihua School of Automation Central South UniversityChangsha 410083China

This study investigates the robust feedback set stabilization of switched logic control networks(SLCNs)with state-dependent uncertain switching and control ***,based on the properties of the semi-tensor product of matrices and the vector representation of logic,an SLCN with state-dependent uncertain switching and control constraints is expressed in algebraic ***,an input transformation and a switching model are constructed to transfer the original SLCN into one with a free control input and arbitrary *** equivalence between the set stabilizability of the original SLCN and that of the resulting SLCN is *** on such equivalence,the authors propose a necessary and sufficient condition for robust feedback set ***,an example is presented to demonstrate the application of the results obtained.

关键词： Input transformation robust control invariant subset robust feedback set stabilizability semi-tensor product state-dependent constraints switched logic control network

Optimized parameters of downhole all-metal PDM based on genetic algorithm

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Petroleum Science 2024年第4期21卷 2663-2676页

作者： Jia-Xing Lu Ling-Rong Kong yu wang Chao Feng yu-Lin Gao China University of Geosciences (Beijing) Key Laboratory on Deep Geo-Drilling Technology of Ministry of Natural Resources

Currently, deep drilling operates under extreme conditions of high temperature and high pressure,demanding more from subterranean power motors. The all-metal positive displacement motor, known for its robust performance, is a critical choice for such drilling. The dimensions of the PDM are crucial for its performance output. To enhance this, optimization of the motor's profile using a genetic algorithm has been undertaken. The design process begins with the computation of the initial stator and rotor curves based on the equations for a screw cycloid. These curves are then refined using the least squares method for a precise fit. Following this, the PDM's mathematical model is optimized, and motor friction is assessed. The genetic algorithm process involves encoding variations and managing crossovers to optimize objective functions, including the isometric radius coefficient, eccentricity distance parameter,overflow area, and maximum slip speed. This optimization yields the ideal profile parameters that enhance the motor's output. Comparative analyses of the initial and optimized output characteristics were conducted, focusing on the effects of the isometric radius coefficient and overflow area on the motor's performance. Results indicate that the optimized motor's overflow area increased by 6.9%, while its rotational speed reduced by 6.58%. The torque, as tested by Infocus, saw substantial improvements of38.8%. This optimization provides a theoretical foundation for improving the output characteristics of allmetal PDMs and supports the ongoing development and research of PDM technology.

关键词： Positive displacement motor Genetic algorithm Profile optimization Matlab programming Overflow area