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Porous silica nano-flowers stabilized Pt-Pd bimetallic nanoparticles as heterogeneous catalyst for efficiently synthesizing guaiacol from 2-methoxycyclohexanol

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Chinese Journal of Chemical Engineering 2024年第6期70卷 222-233页

作者： Junbo Feng junyan Wu Dongdong Yan Yadong Zhang School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization Pingdingshan 467000China Jiyuan Research Institute Zhengzhou UniversityJiyuan 459000China School of Materials and Chemical Engineering Zhongyuan University of TechnologyZhengzhou 450007China

Porous silica nano-flowers(KCC-1)immobilized Pt-Pd alloy NPs(Pt-Pd/KCC-1)with different mass ratios of Pd and Pt were successfully prepared by a facile in situ one-step reduction,using hydrazinium hydroxide as a reducing *** as-synthesized silica nanospheres possess radial fibers with a distance of 15 nm,exhibiting a high specific surface area(443.56 m^(2)·g^(-1)).Meanwhile,the obtained Pt-Pd alloy NPs are uniformly dispersed on the silica surface with a metallic particle size of 4-6 nm,which exist as metallic Pd and Pt on the surface of monodisperse KCC-1,showing the transfer of electrons from Pd to *** as-synthesized 2.5%Pt-2.5%Pd/KCC-1 exhibited excellent catalytic activity and stability for the continuous dehydrogenation of 2-methoxycyclohexanol to prepare *** with Pt or Pd single metal supported catalysts,the obtained 2.5%Pt-2.5%Pd/KCC-1 shows 97.2%conversion rate of 2-methoxycyclohexanol and 76.8%selectivity for guaiacol,which attributed to the significant synergistic effect of bimetallic Pt-Pd alloy ***,turn over frequency value of the obtained 2.5%Pt-2.5%Pd/KCC-1 NPs achieved 4.36 s^(-1),showing higher catalytic efficiency than other two monometallic *** pathways of dehydro-aromatization of 2-methoxycyclohexanol over the obtained catalyst are ***,the obtained 2.5%Pt-2.5%Pd/KCC-1 NPs prove their potential in the dehydrogenation of 2-methoxycyclohexanol,while the kinetics and mechanistic study of the dehydrogenation reaction over the catalyst in a continuous fixed-bed reactor may provide valuable information for the development of green,outstanding and powerful synthetic pathway of guaiacol.

关键词： Supported catalyst Nanoparticles Dehydrogenation 2-Methoxycyclohexanol Guaiacol

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Variational Data Assimilation Method Using Parallel Dual Populations Particle Swarm Optimization Algorithm

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Wuhan University Journal of Natural Sciences 2024年第1期29卷 59-66页

作者： WU Zhongjian LI junyan Detroit Green Institute of Technology Hubei University of TechnologyWuhan 430068HubeiChina School of Information Management Central China Normal UniversityWuhan 430079HubeiChina

In recent years,numerical weather forecasting has been increasingly *** data assimilation furnishes precise initial values for numerical forecasting models,constituting an inherently nonlinear optimization *** enormity of the dataset under consideration gives rise to substantial computational burdens,complex modeling,and high hardware *** paper employs the Dual-Population Particle Swarm Optimization(DPSO)algorithm in variational data assimilation to enhance assimilation *** harnessing parallel computing principles,the paper introduces the Parallel Dual-Population Particle Swarm Optimization(PDPSO)Algorithm to reduce the algorithm processing *** were carried out using partial differential equations,and comparisons in terms of time and accuracy were made against DPSO,the Dynamic Weight Particle Swarm Algorithm(PSOCIWAC),and the TimeVarying Double Compression Factor Particle Swarm Algorithm(PSOTVCF).Experimental results indicate that the proposed PDPSO outperforms PSOCIWAC and PSOTVCF in convergence accuracy and is comparable to *** processing time,PDPSO is 40%faster than PSOCIWAC and PSOTVCF and 70%faster than DPSO.

关键词： parallel algorithm variational data assimilation dual-population particle swarm optimization algorithm diffusion mechanism

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Thermal decomposition mechanism and kinetics of bastnaesite in suspension roasting process:A comparative study in N_(2) and air atmospheres

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Journal of Rare Earths 2024年第9期42卷 1809-1816,I0006页

作者： Wenbo Li Jijia Chen Shaokai Cheng junyan Sun Xiaolong Zhang School of Resources and Civil Engineering Northeastern UniversityShenyang110819China National-Local Joint Engineering Research Center of High-Efficient Exploitation Technology for Refractory Iron Ore Resources Shenyang110819China

To investigate the thermal decomposition behavior and reaction kinetics of bastnaesite in suspension roasting,the gas and solid products of bastnaesite roasted in N2 and air atmospheres were examined using a gas analyzer,X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy dispersive spectrometry(EDS).Subsequently,the kinetic parameters of bastnaesite in the suspension roasting process were derived and calculated using the isothermal *** results show that the decomposition product of bastnaesite in N_(2) is ***,once the roasting temperature exceeds 600℃,CO is generated in addition to CO_(2),and all the XRD diffraction peaks of CeOF are shifted to the right,indicating that CO_(2) can oxidize CeOF and lead to the transformation of Ce(Ⅲ) into Ce(Ⅳ).When roasted in air,the decomposition product CeOF can be completely converted to CeF3 and Ce_(7)O_(12) as it easily ***,the reaction rate of bastnaesite in air is higher than that of N_(2),and the starting reaction temperature is lower than that of N_(2).A large number of irregular cracks and holes appear on the surface of solid-phase products following suspension roasting,which are due to the thermal decomposition of bastnaesite that produces CO_(2) as well as the reconstruction of the lattice of the solid-phase *** reaction kinetic model of bastnaesite roasted in N_(2)(temperature range 600-750℃) and air(temperatu re range 500-575℃) confo rms to the A_(3/2) model with the mechanism function G(α)=-ln(1-α)^(2/3),and the reaction activation energy is 59.78 kj/mol and lnA is 1.65 s^(-1) in N_(2) *** air,the reaction activation energy is 100.30 kj/mol and lnA is 9.63 s^(-1).

关键词： Rare earths Bastnaesite Suspension roasting Thermal decomposition mechanism Reaction kinetics

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Multi-stream signals separation based on space-time-isomeric (SPATIO) array using metasurface antennas

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Science China(Information Sciences) 2024年第2期67卷 181-200页

作者： Yangming LOU Liang JIN Huiming WANG Zhou ZHONG junyan DAI PLA Strategic Support Force Information Engineering University School of Information and Communications Engineering Xi'an Jiaotong University 3. State Key Laboratory of Millimeter WavesSoutheast University

In spatial domain signal processing, it is necessary to equip more antennas at the receiver to improve spatial demultiplexing capability. However, increasing the number of antennas under restricted space will reduce antenna spacing and raise the channel correlation, making the number of signal streams spatially demultiplexed much smaller than that of antennas. This paper proposes a method to design a space-timeisomeric(SPATIO) array based on metasurface antennas under wireless multipath conditions. Each antenna in this array has a different pattern and varies independently with time, reducing the channel correlation by superposing multipath at distinct positions and moments. Based on the SPATIO array, we present an array parameter design scheme based on infinity norm minimization, which can maximize the received energy of each stream while separating multi-stream received signals. Simulation results illustrate the performance of the SPATIO array for multi-stream signal reception. Compared with conventional multiple-input multipleoutput arrays, the proposed array can reduce the bit error rate by one order of magnitude under the same simulation conditions.

关键词： multiple-input multiple-output metasurface antenna space-time-isomeric array multipath channel degree of freedom

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Convolution neural network and 77 GHz millimeter wave radar based intelligent liquid classification system

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Journal of Information and Intelligence 2023年第4期1卷 352-363页

作者： Jiayu Chen Xinhuai Wang Yin Xu Ye Peng Wen Wang junyan xiang Qihang Xu Xidian University and National Key Laboratory of Antennas and Microwave Technology Xidian UniversityXi'an 710071China

An intelligent liquid classification system based on 77 GHz millimeter wave radar and convolution neural network are proposed in this *** data are collected by the AWR1843 radar platform and processed by the neural network on the host PC in *** doppler heatmap generated by radar signal processing is tried for the first time as the input of the *** information carried by the heatmap in 2 dimensions is analyzed and the reason why the doppler heatmap could be used for classification is *** feasible experiment proved that the proposed method can successfully classify 8 kinds of common liquid with high *** result of the experiment is explained and the limitations of the experiment are *** can be drawn that the combination of FMCW millimeter wave radar and convolution neural network is a method with great potential for liquid *** advantages of real time,non-invasive and unilateral measurement can also be used for the detection of dangerous liquids.

关键词： Convolution neural network Doppler heatmap Frequency modulated continuous wave Liquid classification 77 GHz millimeter wave radar

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Asymmetric copolyimide membranes fabricated by nonsolvent-induced phase separation for He/CH_(4) and He/N_(2) separation

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 97-106页

作者： Ying Li Lu Wang junyan Xie Yong Dai Xuehong Gu Xuerui Wang State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China Quzhou Membrane Material Innovation Institute Quzhou 324000China

Membrane gas separation is considered an energy-saving technique to extract He from natural gas due to no phase change and room temperature ***,the membrane performance was strongly limited by the trade-off between permeance and ***,novel 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)-2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(APAF)-5-amino-2-(4-aminobenzene)benzimidazole(BIA)asymmetric membranes with a thickness of 300 nm were successfully prepared by the non-solvent induced phase separation *** membrane performance was modulated by regulating dope solution compositions(e.g.,tetrahydrofuran and polymer concentration).The ideal He/CH_(4) selectivity was 124 and the optimized He permeance reached 87 GPU,beyond the current upper ***/CH_(4) selectivity was 75 and He permeance was 73 GPU for the binary mixture feed containing 0.2 mol%*** membrane showed good resistance to CO_(2) and C_(2)H_(6),which are the typical impurities in natural *** 6FDA-APAF-BIA membranes have good stability(>160 h),which can provide great potential in He extraction from natural gas.

关键词： He separation membrane natural gas copolyimide

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Performance of composite foundations with different load transfer platforms and substratum stiffness over silty clay

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Journal of Mountain Science 2024年第5期21卷 1761-1774页

作者： ZHANG Shuming LIU Yan YUAN Shengyang LIU Xianfeng JIANG Guanlu LIU junyan School of Civil Engineering and Architecture University of JinanJinan 250022China The Engineering Technology Research Center for Urban Underground Engineering Supporting and Risk Monitoring of Shandong Province Jinan 250022China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Key Laboratory of High-speed Railway Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 610031China

The semi-rigid pile-supported composite foundation is widely used in highway projects due to its effectiveness in increasing the bearing capacity and stability of *** is crucial to understand the stress distribution across the embankment width and the behaviour of unreinforced ***,five centrifuge tests were conducted to examine the bearing and deformation behaviours of NPRS(Non-Connected Piled Raft Systems)and GRPS(GeosyntheticReinforced Pile-Supported systems)with varying substratum stiffness,then a comparative analysis was conducted on embankment settlement,pressures underneath the embankments,and axial forces along the *** results indicated that greater substratum stiffness correlates with reduced settlement and deformation at various *** occurring 5 meters from the embankment toe includes settlement in NPRS and upward movement in *** potential sliding surface is primarily located within the embankment in NPRS,whereas it may extend through both the embankment and foundation in *** pile-soil stress ratio and efficiency in NPRS are higher than in GRPS across the *** axial force borne by end-bearing piles is significantly greater than that by floating *** the buried depth increases,the axial force in GRPS initially rises then declines,whereas in NPRS,it remains relatively constant within a certain range before *** study aids in assessing the applicability of composite foundations in complex railway environments and provides a reference for procedural measures under similar conditions.

关键词： Centrifuge modelling Composite foundation Failure mode Load transfer platform Substratum Stiffness Silty clay

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Single-Crystal Seeds Inducing the Crystallization of High-performance α-FAPbI3 for Efficient Perovskite Solar Cells

Single-Crystal Seeds Inducing the Crystallization of High-pe...

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第十届新型太阳能材料科学与技术学术研讨会

作者： Jun He junyan xiang Hongli Liu Fei Zhang xianggao Li Shirong Wang Tianjin University School of Chemical Engineering and Technology Collaborative Innovation Center of Chemical Science and Engineering(Tianjin)

α-phase formamidine lead iodine(α-FAPbI) as the competitive candidates to pursue highperformance perovskite solar cells(PSCs) suffers the weakness of random nucleation and disordered growth in chasing high-grade polycrystalline ***,single-crystal seeds crystallization(SCSC) method is proposed to obtain high-quality α-FAPbI perovskite films for the first *** single-crystals seeds(CsPbBr,CsPbI,FAPbBr,FAPb,MAPbBr,MAPbI) are employed to regulate α-FAPbI perovskite *** seeds act as nucleation sites and allow perovskite to grow *** rapid crystallization significantly improves the crystallinity of perovskite films with uniform morphology,large grain size,and less ***,FAPbBr seed prefers to grow α-FAPbI epitaxially from FAPbBr@PbI heterostructure through halogen anions exchange *** average grain size of FAPbBr-perovskite film is boosted to 2.6 μm,and the trap density reduced by 11 *** FAPbBr-PSCs achieve the maximum power conversion efficiency(PCE) of 23.84% with a high opencircuit voltage of 1.18 *** unencapsulated PSC enables to retain 91% of the initial PCE after 3000 hours of storage at 30～50% relative humidity and preserves 98.5% of the original value after 155 hours illumination with maximum power point tracking.

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Enhanced plasticity of spontaneous coagulation cast oxide ceramic green bodies

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Journal of Advanced Ceramics 2024年第5期13卷 568-578页

作者： Juanjuan Wang Jin Zhao junyan Mao Wenlong Liu Haohao Ji Jian Zhang Shiwei Wang State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

In the preparation of large-sized ceramics,the use of a green body with relatively high plasticity is crucial to minimize the risk of cracking during *** achieve this goal,glycerol and polyethylene glycol(PEG)were utilized as plasticizers in the shaping of green bodies of oxide ceramics through spontaneous coagulation casting(SCC).This study investigated the effects of plasticizers and particle sizes ranging from the submicron to nanoscale on the slurry viscosity,drying shrinkage of wet gels,and mechanical properties of green *** plasticity of the green bodies was assessed by measuring the impact toughness and flexural stress‒strain *** incorporating an appropriate plasticizer,the peak width of the flexural stress‒strain curve for dried green bodies from particles of different sizes was nearly twice that without plasticizers,and the impact toughness was enhanced by approximately 71%,34%,and 41%when the particle size decreased from the submicron scale to the nanoscale(0.45μm,0.18μm,and 50 nm,respectively).The drilling test revealed that there was nearly no cracking around the holes in the green bodies with *** plasticity mechanism of the green bodies was examined based on ultraviolet–visible(UV–Vis)spectroscopy and scanning electron microscopy(SEM).It was discovered that plasticizers might mitigate the brittleness of green bodies by adjusting the interactions between molecules and modifying the gel network properly.

关键词： green body plasticity plasticizer particle size impact toughness stress-strain curve

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Controllability Gramian-based measures of graph product networks

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Science China(Information Sciences) 2024年第10期67卷 315-331页

作者： Yuequan xiang Linying xiang School of Information Science and Engineering Northeastern University School of Artificial Intelligence Tiangong University

This paper addresses the controllability measures of composite networks based on graph products, in which the graph product networks are either Kronecker product networks or Kronecker sum *** primary objective pursued here is to reveal the controllability Gramian-based measure links between the graph product composite network and its subnetworks. First, the analytical expression of the average controllability for the Kronecker product network is derived by using the corresponding controllability measures of its subnetworks. An upper bound of volumetric control energy is further obtained for the Kronecker product network. Then, the upper bounds are derived for the controllability measures of the Kronecker sum network,which provide a valuable reference for designing controllable networks in practical applications. Finally, the controllability of the Kronecker product network is compared with that of the Kronecker sum network, and it is found that when the subnetworks satisfy certain conditions, the Kronecker product network has better average controllability than the Kronecker sum network.

关键词： composite network graph product controllability Gramian-based measure average controllability control energy

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