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Study on methanol synthesis from coal-based syngas

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Journal of Coal Science & Engineering(China) 2009年第1期15卷 98-103页

作者： ma Hong-fang YING wei-yong fang Ding-ye State Key Laboratory of Chemical Engineering East China University of Science and Technology Shanghai 200237 China

The intrinsic kinetic models of the Langmuir-Hinshelwood type were investigated in terms of the reaction rates of CO hydrogenation and CO_2 hydrogenation in theform of reactant fugacity. The parameters were estimated by the Universal Global Optimization using the marquardt method. Residual error distribution and statistic tests show thatthe intrinsic kinetic models are reliable and acceptable. The mathematic model of a combined converter formed by gas-cooled and water-cooled reactor was developed and thegas-cooled reactor and the water-cooled reactor were characterized with one-dimensionalmathematic model. The distributions of temperature and concentration in the catalytic bedof the gas-cooled reactor and the water-cooled reactor in a combined converter with ayield of 1.2 Mt/a were simulated. The parallel cross linking pore model was used to describe the transfer process of multi-component diffusion system in the catalyst. The calculated value computed by the internal diffusion efficiency factor calculation model established for methanol synthesis catalyst fit the experimental value very well.

关键词： methanol coal-based syngas kinetics diffusion

Supercapacitor Performance of Hollow Carbon Spheres by Direct Pyrolysis of Melamine-formaldehyde Resin Spheres

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Chemical Research in Chinese Universities 2013年第4期29卷 735-742页

作者： ma fang-wei SUN Li-ping ZHAO Hui LI Qiang HUO Li-hua XIA Tian GAO Shan Key Laboratory of Functional Inorganic material Chemistry Ministry oJ Education School of Chemistry and Material Science Key Laboratory of Chemical Engineering Process & Technology for High-efficiency Conversion of Heilongjiang Province Heilong/iang University Harbin 150080 P. R. China

The nitrogen and oxygen co-doped hollow carbon spheres（HCSs） were prepared via a simple pyrolysis of solid melamine-formaldhyde resin spheres. The carbonization temperature has an important influence on the specific surface area, pore-size distribution and heteroatom contents of HCSs. The synergistic effects of those physical and chemical properties on supercapacitor performance were systematically investigated. Among the HCSs obtained at different temperatures, HCSs-800（co-doped HCSs at 800℃） exhibits the best reversible specific capacitance in 2 mol/L H2SO4 electrolyte and meanwhile maintains a high-class capacitance retention capability. The nitrogen heteroatoms were confirmed to play a crucial role in improving capacitance in an acid medium. This kind of nitrogen doved HCSs is a potential candidate for an efficient electrode material for supercapacitors.

关键词： Hollow carbon sphere Pyrolysis Melamine-formaldehyde resin Supercapacitor Nitrogen-dope

Enhancing personalized exercise recommendation with student and exercise portraits

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Journal of Electronic Science and Technology 2024年第2期22卷 91-109页

作者： wei-wei Gao Hui-fang ma Yan Zhao Jing Wang Quan-Hong Tian College of Computer Science and Engineering Northwest Normal UniversityLanzhou730070China Computer Center of Gansu Province Lanzhou730070China

The exercise recommendation system is emerging as a promising application in online learning scenarios,providing personalized recommendations to assist students with explicit learning *** solutions generally follow a collaborative filtering paradigm,while the implicit connections between students(exercises)have been largely *** this study,we aim to propose an exercise recommendation paradigm that can reveal the latent connections between student-student(exercise-exercise).Specifically,a new framework was proposed,namely personalized exercise recommendation with student and exercise portraits(PERP).It consists of three sequential and interdependent modules:Collaborative student exercise graph(CSEG)construction,joint random walk,and recommendation list ***,CSEG is created as a unified heterogeneous graph with students’response behaviors and student(exercise)***,a joint random walk to take full advantage of the spectral properties of nearly uncoupled markov chains is performed on CSEG,which allows for full exploration of both similar exercises that students have finished and connections between students(exercises)with similar ***,we propose to optimize the recommendation list to obtain different exercise *** analyses of two public datasets,the results demonstrated that PERP can satisfy novelty,accuracy,and diversity.

关键词： Educational data mining Exercise recommend Joint random walk Nearly uncoupled markov chains Optimization Personalized learning

Microstructures,corrosion behavior and mechanical properties of as-cast Mg-6Zn-2X(Fe/Cu/Ni)alloys for plugging tool applications

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International Journal of Minerals,Metallurgy and materials 2024年第4期31卷 697-711页

作者： Baosheng Liu Jiali wei Shaohua Zhang Yuezhong Zhang Pengpeng Wu Daqing fang Guorui ma School of materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China State Key Laboratory for Mechanical Behavior of materials Xi’an Jiaotong UniversityXi’an 710049China Intelligent Equipment Research and Development Center Zhuhai Institute of Advanced Technology Chinese Academy of SciencesZhuhai 519080China Advanced materials Research Institute Zhuhai Dingmei Medical Technology Co.Ltd.Zhuhai 519000China

Mg-6Zn-2X(Fe/Cu/Ni)alloys were prepared through semi-continuous casting,with the aim of identifying a degradable magnesium(Mg)alloy suitable for use in fracturing balls.A comparative analysis was conducted to assess the impacts of adding Cu and Ni,which result in finer grains and the formation of galvanic corrosion *** electronic microscopy examination revealed that precipitated phases concentrated at grain boundaries,forming a semi-continuous network structure that facilitated corrosion penetration in Mg-6Zn-2Cu and Mg-6Zn-2Ni *** corrosion was observed in Mg-6Zn-2Fe,while galvanic corrosion was identified as the primary mechanism in Mg-6Zn-2Cu and Mg-6Zn-2Ni *** the tests,the Mg-6Zn-2Ni alloy exhibited the highest corrosion rate(approximately 932.9 mm/a)due to its significant potential *** testing showed that Mg-6Zn-2Ni alloy possessed suitable ultimate compressive strength,making it a potential candidate material for degradable fracturing balls,effectively addressing the challenges of balancing strength and degradation rate in fracturing applications.

关键词： magnesium alloys microstructure micro-galvanic corrosion mechanical properties

Fast charge transfer kinetics in Sv-ZnIn_(2)S_(4)/Sb_(2)S_(3)S-scheme heterojunction photocatalyst for enhanced photocatalytic hydrogen evolution

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Rare Metals 2024年第2期43卷 533-542页

作者： wei Li Jia-Jun Li Zhi-Fei Liu Hong-Yu ma Peng-Fei fang Rui Xiong Jian-Hong wei Key Laboratory of Artificial Micro-and Nano-Structures of Ministry of Education School of Physics and TechnologyWuhan UniversityWuhan430072China

Constructing a S-scheme heterojunction with tight interface contact and fast charge transfer is beneficial to improving the photocatalytic hydrogen evolution ***,a unique one-dimensional(1D)/two-dimensional(2D)S-scheme heterojunction containing 1D Sb_(2)S_(3) nanorods and 2D ZnIn_(2)S_(4) with affluent sulfur vacancies(denoted as Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3)) was *** introduced sulfur vacancy can promote the effective adsorption of H+for the following interfacial hydrogen-evolution ***,the larger contact area and stronger electron interaction between Sb_(2)S_(3) and ZnIn_(2)S_(4) effectively inhibits the recombination of photo-generated electron–hole pairs and abridges the migration distance of *** a result,the optimal Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) sample achieves H_(2) evolution activity of 2741.3 mol·h^(−1)·g^(−1),which is 8.6 times that of pristine ZnIn_(2)S_(4) and 3.0 times that of the Sv-ZnIn_(2)S_(4) *** on the experimental result,the photo-reactivity S-scheme mechanism of hydrogen evolution from water splitting with Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) is *** work provides an effective method for developing S-scheme heterojunction composites of transition metal sulfide with high hydrogen evolution performance.

关键词： ZnIn_(2)S_(4) nanosheets S-scheme heterojunction Sulfur vacancy Charge transfer and separation Photocatalytic H_(2)evolution

Data driven reduced modeling for fluidized bed with immersed tubes based on PCA and Bi-LSTM neural networksAuthor links open overlay panel

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Particuology 2024年第8期91卷 1-18页

作者： Jiabin fang Wenkai Cu Huang Liu Huixin Zhang Hanqing Liu Jinjia wei Xiang ma Nan Zheng School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'anShaanxi 710049China

The fast and accurate reduced-order modeling of fluidized beds is a challenging task in the field of fluid dynamics,owing to their high dimensionality and nonlinear dynamic *** this study,a nonintrusive reduced order modeling method,the reduced order model based on principal component analysis and bidirectional long short-term memory networks(PBLSTM ROM),was developed to capture complex spatio-temporal dynamics of fluidized *** combining principal component analysis and Bidirectional long-short-term memory networks,the PBLSTM ROM effectively extracted dynamic evolution information without any prior knowledge of governing equations,enabling reduced-order modeling of unsteady flow *** PBLSTM ROM was validated using the solid volume fraction and gas velocity flow fields of a fluidized bed with immersed tubes,showing superior performance over both the PLSTM and PANN ROMs in accurately capturing temporal changes in the fluidization fields,especially in the region near immersed tubes where severe fluctuations ***,the PBLSTM ROM improved the simulation speed by five orders of magnitude compared to traditional computational fluid dynamics *** findings suggest that the PBLSTM ROM presents a promising approach for analyzing the complex fluid flows in engineering practice.

关键词： Reduced order modeling Fluidized bed Deep learning Bi-LSTM

A rigorous real-time acoustic positioning method for ocean bottom seismic exploration

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Satellite Navigation 2024年第1期5卷 168-190页

作者： Jinye ma Shouchuan fang Jianhu Zhao School of Geodesy and Geomatics Wuhan University129 Luoyu RoadWuhan430079China Institute of marine Science and Technology Wuhan UniversityWuhan430079China Surveying Service Center BGP Inc.CNPCZhuozhou072751HebeiChina

The conventional technique for positioning seafloor geophones in ocean bottom seismic exploration encounters several challenges,including the significant impact of outliers on positioning results,underutilization of high-precision observations,and low efficiency in real-time data *** issues inevitably affect the quality of seismic exploration *** address these challenges and enhance the accuracy of geophone positioning,this paper proposes a rigorous real-time acoustic positioning method for geophones based on sequential adjustment and Baarda's outlier detection *** proposed method comprises three key steps:grouping the original acoustic observations,constructing the intra-group acoustic positioning model,and synthesizing the positioning results across the different *** validity and practicality of this approach are confirmed through a simulation experiment as well as the field experiment conducted in the Bohai Sea,*** results demonstrate that the proposed method effectively eliminates outliers in the original observations and maximizes the utilization of high-quality *** to traditional acoustic positioning methods,it significantly reduces positioning errors from meters to decimeters,and in some cases can achieve centimeter-level *** the sound velocity profile in the operating sea area is measured,the method can attain the posterior standard deviation at the millimeter level and positioning errors within 10 *** the sound velocity profile is unknown,the method can achieve the posterior standard deviation at centimeter-level and positioning errors of approximately 20 cm.

关键词： Ocean bottom seismic exploration Geophone positioning Acoustic positioning method Sequential adjustment Outlier detection

Transient Response and Ionic Dynamics in Organic Electrochemical Transistors

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Nano-Micro Letters 2024年第11期16卷 191-223页

作者： Chao Zhao Jintao Yang wei ma State Key Laboratory for Mechanical Behavior of materials Xi’an Jiaotong UniversityXi′an 710049People’s Republic of China

The rapid development of organic electrochemical transistors(OECTs)has ushered in a new era in organic electronics,distinguishing itself through its application in a variety of domains,from high-speed logic circuits to sensitive biosensors,and neuromorphic devices like artificial synapses and organic electrochemical random-access *** recent strides in enhancing OECT performance,driven by the demand for superior transient response capabilities,a comprehensive understanding of the complex interplay between charge and ion transport,alongside electron–ion interactions,as well as the optimization strategies,remains *** review aims to bridge this gap by providing a systematic overview on the fundamental working principles of OECT transient responses,emphasizing advancements in device physics and optimization *** review the critical aspect of transient ion dynamics in both volatile and non-volatile applications,as well as the impact of materials,morphology,device structure strategies on optimizing transient *** paper not only offers a detailed overview of the current state of the art,but also identifies promising avenues for future research,aiming to drive future performance advancements in diversified applications.

关键词： Organic electrochemical transistors Transient response Ion dynamics Electronic dynamics Volatility and non-volatility

Dietary supplementation of benzoic acid and essential oils combination enhances intestinal resilience against LPS stimulation in weaned piglets

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Journal of Animal Science and Biotechnology 2024年第2期15卷 878-897页

作者： Chang Cui Yulong wei Yibo Wang Wen ma Xiaoyu Zheng Jun Wang Ziwei ma Caichi Wu Licui Chu Shihai Zhang Wutai Guan fang Chen Guangdong Provincial Key Laboratory of Animal Nutrition Control College of Animal ScienceSouth China Agricultural UniversityGuangzhou 510642China College of Animal Science and National Engineering Research Center for Breeding Swine Industry South China Agricultural UniversityGuangzhou 510642China Guangdong Laboratory for Lingnan Modern Agriculture South China Agricultural UniversityGuangzhou 510642China

Background The benefits of combining benzoic acid and essential oils(BAO)to mitigate intestinal impairment during the weaning process have been well established,while the detailed underlying mechanism has not been fully *** research has primarily focused on the reparative effects of BAO on intestinal injury,while neglecting its potential in enhancing intestinal stress *** In this study,we investigated the pre-protective effect of BAO against LPS-induced stress using a modified experimental *** were pre-supplemented with BAO for 14 d,followed by a challenge with LPS or saline to collect blood and intestinal *** Our findings demonstrated that BAO supplementation led to significant improvements in piglets’final weight,average daily gain,and feed intake/body gain ***,BAO supplementation positively influenced the composition of intestinal microbiota,increasing beneficial Actinobacteriota and Alloprevotella while reducing harmful Desulfobacterota,Prevotella and ***,BAO supplementation effectively mitigated oxidative disturbances and inflammatory responses induced by acute LPS *** was evidenced by elevated levels of T-AOC,SOD,and GSH,as well as decreased levels of MDA,TNF-α,and IL-6 in the ***,piglets subjected to LPS challenge and pre-supplemented with BAO exhibited significant improvements in intestinal morphological structure and enhanced integrity,as indicated by restored expression levels of Occludin and Claudin-1 compared to the non-supplemented *** analysis revealed that BAO supplementation enhanced the jejunal antioxidative capacity by increasing GSH-Px levels and decreasing MDA levels under the LPS challenge and stimulated the activation of the Nrf2 signaling ***,the reduction of TLR4/NF-κB/maPK signaling pathways activation and proinflammatory factor were also observed in the jejunal of those piglets fed with ***

关键词： Anti-stress Benzoic acid Essential oils Intestine LPS Weaned piglets