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Oxidative coupling of methane in a dual-bed reactor comprising of particle/cordierite monolithic catalysts

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Journal of Natural Gas Chemistry 2010年第6期19卷 600-604页

作者： deng pan Shengfu Ji Wenhua Wang Chengyue Li State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijng 100029 China

A dual-bed reactor was constructed comprising of a 5%Na2WO4-2%Mn/SiO2 particle catalyst and a 4%Ce-5%Na2WO4-2%Mn/SiO2 /cordierite monolithic *** reaction performance of the oxidative coupling of methane （OCM） over the dual-bed reactor system was *** effects of the bed height and operation mode,as well as the reaction parameters such as reaction temperature,CH4/O2 ratio and flowrate of feed gas,on the catalytic performance were *** results indicated that the suggested dual-bed reactor exhibited a good performance for the OCM reaction when the feed gases firstly passed through the particle catalyst bed and then to the monolithic catalyst bed.A CH4 conversion of 38.2% and a C2H4 selectivity of 43.3% could be obtained using the dual-bed reactor with a particle catalyst bed height of 10 mm and a monolithic catalyst bed height of 50 *** the CH4 conversion and C2H4 selectivity have increased by 2.5% and 12.8%,respectively,as compared with the 5%Na2WO4-2%Mn/SiO2 particle catalyst in a conventional single-bed reactor and by 12.9% and 23.0%,respectively,as compared with the 4%Ce-5%Na2WO4-2%Mn/SiO2 /cordierite monolithic catalyst in a single-bed *** catalytic performance of the OCM in the dual-bed reactor system has been improved remarkably.

关键词： oxidative coupling of methane dual-bed reactor monolithic catalysts

Digital Gene Expression Analysis of Huanglongbing Affected Mandarins(Citrus reticulata Blanco)In Response to Thermotherapy

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Horticultural Plant Journal 2021年第1期7卷 1-12页

作者： Ruixuan pan Yanling Chen Xiaoling deng Meirong Xu Laboratory of Citrus Huanglongbing Research Guangdong Key Laboratory of Microbial Signals and Disease ControlSouth China Agricultural UniversityGuangzhou 510642China

Huanglongbing(HLB),which is mainly associated with“Candidatus Liberibacter asiaticus”(CLas),is currently threatening citrus production around the *** destructive century-old disease results in callose deposition in phloem plasmodesmata and starch overaccumulation in leaf *** treatment with high humidity has proven to be effective in eliminating the CLas titers in potted citrus *** study explored the curative mechanisms and impact of heat treatment(from 32 to 48°C with 75%±5%relative humidity,14h in light and 10h in dark for four days)on mandarin trees(Citrus reticulata Blanco)that were severely infected by CLas using Solexa/Illumina’s digital gene expression(DGE)profiling.A total of 838 differentially expressed genes(DEGs)were identified,of which 510 were *** interaction analysis of the DEGs indicated that the thermotherapy of HLB trees downregulated the circadian clock related genes in chloroplasts and upregulated the RNA-editing process in the mitochondria,characterized by 141 genes encoding pentatricopeptide repeatcontaining proteins(PPR)being all ***,the expression of phenylpropanoid and flavonoid biosynthesis genes,and auxininduced genes were *** defense response pathway of the thermotherapy treated diseased trees was apparently disrupted,as indicated by the downregulation of LRR receptor-like serine/threonine-protein kinase FLS2 *** study improves our understanding of the curative mechanisms of heat treatment on HLB trees and CLas biological ***,this provides new insights on the involvement of RNA modification by PPR genes and changes in the circadian clock after the heat stress treatment of CLas-infected citrus.

关键词： Citrus huanglongbing heat transcriptom differentially expressed genes

Robot trajectory planning for autonomous 3D reconstruction of cockpit in aircraft final assembly testing

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Chinese Journal of Aeronautics 2024年第3期37卷 332-350页

作者： Yanzhe WANG Zemin pan Qian YANG Changxi deng Yanding WEI The State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou 310027China School of Information Science and Engineering NingboTech UniversityNingbo 315100China AVIC Xi’an Aircraft Industry(Group)Company Ltd. Xi’an 710089China Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province School of Mechanical EngineeringZhejiang UniversityHangzhou 310027China

The trend towards automation and intelligence in aircraft final assembly testing has led to a new demand for autonomous perception of unknown cockpit operation scenes in robotic collaborative airborne system *** address this demand,a robotic automated 3D reconstruction cell which enables to autonomously plan the robot end-camera’s trajectory is developed for image acquisition and 3D modeling of the cockpit operation scene.A continuous viewpoint path planning algorithm is proposed that incorporates both 3D reconstruction quality and robot path quality into optimization *** metrics for viewpoint position paths and orientation paths are introduced together for the first time in 3D *** ensure safe and effective movement,two spatial constraints,Domain of View Admissible Position(DVAP)and Domain of View Admissible Orientation(DVAO),are implemented to account for robot reachability and collision *** using diffeomorphism mapping,the orientation path is transformed into 3D,consistent with the position *** orientation and position paths can be optimized in a unified framework to maximize the gain of reconstruction quality and path smoothness within DVAP and *** reconstruction cell is capable of automatic data acquisition and fine scene modeling,using the generated robot C-space *** and physical scene experiments have confirmed the effectiveness of the proposed method to achieve highprecision 3D reconstruction while optimizing robot motion quality.

关键词： Aircraft assembly testing Aircraft cockpit 3D modeling Camera viewpoint Robot trajectory planning

Multi-channel discharge characteristics cutting by ultra-fine wire-EDM

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Chinese Journal of Aeronautics 2022年第2期35卷 308-319页

作者： Ming ZHANG zhidong LIU Hongwei pan Cong deng Mingbo QIU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Compared with a copper wire electrode, molybdenum wire with a poor conductor is usually used as the electrode in high speed wire-cut electrical discharge machining(HSWEDM), so the resistance of an ultra-fine wire cannot be ignored. To study the differences of discharge characteristics between the ultra-fine wire and the conventional diameter wire, the continuous discharge waveform of two kinds of wire electrodes was compared. It was found that there was a multichannel discharge phenomenon in the discharge waveform cutting by ultra-fine wire. Through the establishment of a discharge equivalent circuit model and the simulation analysis of the electrostatic field, it was found that the reason why ultra-fine wire is easy to form multi-channel discharge phenomenon is that the potential difference between the wire and the workpiece increased linearly along the axis of the wire. Besides, etching products like metal particles will distort the electric field between the electrodes. Both of them make it easy to form a multi-channel discharge in *** results show that the distributions of the equivalent resistance and the peak current are affected by the multi-channel discharge position. Multi-channel discharge can disperse energy and increase effective discharge frequency. Compared with the 0 mm spacing, at a spacing of 100 mm, the machining efficiency increases by 8.7%, the surface roughness decreases by 37.7%, and the average recast layer thickness decreases by 46.6% under the condition of ultra-fine wire-EDM.

关键词： HSWEDM Multi-channel Recast layer Surface roughness Ultra-fine wire

Joint parameter and state estimation for stochastic uncertain system with multivariate skew t noises

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Chinese Journal of Aeronautics 2022年第5期35卷 69-86页

作者： Shuhui LI zhihong deng Xiaoxue FENG Ruxuan HE Feng pan School of Automation Beijing Institute of TechnologyBeijing 100081China Kunming-BIT Industry Technology Research Institute INC Kunming 650106China

Due to the pulse interference, measurement outliers and artificial modeling errors, the multivariate skew t noise widely exists in the real environment. However, to date, little attention has been paid to the state estimation for systems in which the process noise and the measurement noise are both modeled as the heavy-tailed and skew non-Gaussian noise. In this paper, the multivariate skew t distribution is utilized to model the heavy-tailed and skew non-Gaussian noise. Then a probabilistic graphical form of the multivariate skew t distribution is given and proved. Based on the probabilistic graphical form, a hierarchical Gaussian state space model for stochastic uncertain systems is proposed, which transforms the estimation problem for systems with the heavy-tailed and skew non-Gaussian noises into the one with a hierarchical Gaussian state space model. Next, given the designed Gaussian state space model, the robust Bayesian filter and smoother based on the variational Bayesian inference are proposed to approximately estimate the system state and the unknown noise parameters. Furthermore, the complexity analysis together with the controllability and observability for stochastic uncertain systems with multivariate skew t noises is given. Finally,the simulation results of the target tracking scenario verify the validity of the proposed algorithms.

关键词： Estimation methods Non-Gaussian noise Target tracking Uncertain systems Variational principles

Strawberry vein banding virus P6 protein intracellular transport and an important domain identification

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Journal of Integrative Agriculture 2018年第9期17卷 2031-2041页

作者： pan Yuan ZHOU xiu-hong LI Shuai FENG Ming-feng SHI Man-ling ZUO deng-pan JIANG Xi-zi CHEN Jing HU Ya-hui ZHANG Xiang-xiang JIANG Tong School of Plant Protection Anhui Agricultural University Biotechnology Center Anhui Agricultural University College of Life and Environmental Sciences Hangzhou Normal University

Strawberry vein banding virus （SVBV）-infected strawberry cells contain cytoplasmic inclusions with isometric particles. To identify the components of the inclusions, green fluorescent protein （GFP） was fused to the carboxy-terminus （C-terminus） of SVBV open reading frames, these constructs were separately transformed into Agrobacterium tumefaciens and infiltrated into Nicotiana benthamiana leaves. Results showed that the SVBV P6 protein assembled into prominent and amorphous inclusion bodies （IBs）. To investigate P6 subcellular localization, P6-GFP was ectopically expressed in N. benthamiana leaves by agroinfiltration and then stained with 4＂,6-diamidino-2-phenylindole （DAPI）. We found the P6 protein accumulated in the nuclei and also formed cytoplasmic IBs with different sizes. To further determine the location of P6 IBs in the cytoplasm, and explore whether the P6 IBs move freely or depend on cytoskeleton and endoplasmic reticulum （ER）, the microfilament marker protein （GFP-ABD2-GFP）, microtubules marker protein （mCherry-MAP65-1） and ER marker protein （mCherry-HDEL） were separately coexpressed with P6-GFP and into N. benthamiana leaves by agroinfiltration, exhibiting that P6 IBs aligned with cytoskeleton and endoplasmic reticulum. Meanwhile, coinfiltration of P1 and P6 indicated the P6 colocalized with the P1 protein at periphery of cells. The P6 protein contains one C-terminal nuclear localization signal （NLS） region, a P6 protein mutant with a deleted NLS did not localize in the nucleus, did not form IBs, and was unable to facilitate exogenous GFP expression. These results demonstrate that the deleted NLS region is an important P6 domain required for biological functions. In summary, the mobile P6 IBs are associated with ER, microfilaments and microtubules and move along microfilaments to the SVBV P1 protein in the PD.

关键词： SVBV IBs intracellular transport cytoskeleton ER P6 mutant

Preparation of tungsten-particle-reinforced Zr-based bulk metallic glass composites by two-step spark plasma sintering:microstructure evolution,densification mechanism and mechanical properties

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Rare Metals 2024年第4期43卷 1793-1808页

作者： Yun-Fei Ma pan Gong Mao Zhang Hui-EHu Zhen Peng Xiao Xu xin Wang Mehdi Malekan Xue-Feng Tang Lei deng Jun-Song Jin xin-Yun Wang State Key Laboratory of Materials Processing and Die and Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Research Institute of Huazhong University of Science and Technology in Shenzhen Shenzhen518057China Department of Chemistry and Materials Naval University of EngineeringWuhan430032China School of Materials Science and Engineering Jiangsu UniversityZhenjiang212013China College of Machine Shanghai Dianji UniversityShanghai201306China School of Metallurgy and Materials Engineering College of EngineeringUniversity of TehranTehran 11155-4563Iran

A new two-step spark plasma sintering(TSS)process with low-temperature pre-sintering and high-temperature final sintering has been successfully applied to prepare the tungsten-particle(Wp)-reinforced bulk metallic glass composites(Wp/BMGCs).Compared to normal spark plasma sintering(NS),the densification rate and relative density of Wp/BMGCs can be improved by selecting TSS with appropriate sintering pressure in the low temperature pre-sintering ***,the compressive strength and plastic strain of 30%Wp/BMGCs prepared by TSS are both higher than those of the samples prepared by *** TSS process can significantly enhance the compressive strength of 30%Wp/BMGCs by 12%and remarkably increase the plastic strain by 50%,while the trend is completely opposite for 50%Wp/***-in situ experiments and finite element simulations reveal that uneven temperature distribution among particles during low-temperature pre-sintering causes local overheating at contact points between particles,accelerating formation of sintering neck between particles and plastic deformation of *** the volume fraction of Wp is low,TSS can improve the interface bonding between particles by increasing the number of sintering *** makes the fracture mode of Wp/BMGCs being predominantly transgranular ***,as the volume fraction of Wp increases,the adverse effects of Wp plastic deformation are becoming more and more *** aggregated Wp tends to form a solid"cage structure"that hinders the bonding between particles at the interface;correspondingly,the fracture behavior of Wp/BMGCs is mainly dominated by intergranular ***,reducing the sintering pressure during the low-temperature pre-sintering stage of TSS has been shown to effectively decrease plastic deformation in Wp,resulting in a higher degree of densification and better mechanical properties.

关键词： Bulk metallic glass composites Tungsten particle Two-step spark plasma sintering Densification mechanism Mechanical properties

Effect of no-load rate on recast layer cutting by ultra fine wire-EDM

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Chinese Journal of Aeronautics 2021年第4期34卷 124-131页

作者： Ming ZHANG zhidong LIU Hongwei pan Cong deng Mingbo QIU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Via material erosion in wire electrical discharge machining(WEDM),recast layers form on the surfaces of *** addition,ultra fine Wire-EDM can be usually cut *** reduce the thickness of the recast layer as much as possible,the wire electrical discharge-electrochemical machining(WEDCM)method was proposed,which is based on the micro conductivity of the dielectric and microelectrolytic characteristics by adjusting the no-load rate of the pulse in the machining ***,a state discrimination and servo control system based on discharge current was *** experiment results of different no-load rates show that the electrolytic effects increase as the no-load rate increases,and the main machining process is spark discharge erosion with a no-load rate in the range of 10%to 80%.At 90%no-load rate,the amount of recast layer formation in the forward direction of the wire electrode is almost the same as that of electrolytic dissolution,and it can be practically processed without a recast *** with10%no-load rate,the kerf width only increases by 7.5%.

关键词： Electrolytic dissolution coefficient No-load rate Recast layer Ultra fine wire WEDCM

Fast-chargingand dendrite-free lithiummetal anodeeenabledby partial lithiation ofgraphene aerogel

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Nano Research 2022年第11期15卷 9792-9799页

作者： yong Ma Yuting Gu Ying He Le Wei Yuebin Lian Weiyi pan xinjian Li Yanhui Su Yang Peng Zhao deng Zhongfan Liu College of Energy Soochow Institute for Energy and Materials Innovations(SIEMIS)Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu ProvinceSoochow UniversitySuzhou 215006China School of Photoelectric Engineering Changzhou institute of technologyChangzhou 213032China Beijing Graphene Institute(BGI) Beijing 100095China Center for Nanochemistry(CNC) College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The development of deeply cyclable lithium metal batteries with fast-charging capability offers a promising solution to relieve the“range anxiety”in driving electric *** lithium metal anodes suffered from low operating current densities and shallow charge/discharge depths,owing to the intrinsic dendrite growth governed by Sand’s ***,we come up with a novel design of heavy-duty lithium metal anode fabricated by partially infusing the three-dimensional(3D)porous graphene aerogel with molten *** electroanalytical measurements and simulations show that the unique electrode architecture brings notable advantages in mediating smooth Li plating/stripping,including reduced local current density,inhibited dendrite growth,buffered volume fluctuation,as well as more efficient Li ***,a remarkable cycling performance in symmetric cells for over 400 cycles(800 h)with an ultrahigh cycling capacity of 15 mAh·cm^(−2) at 15 mA·cm^(−2) is achieved,which,to our best knowledge,has been never seen in ***4 full cells demonstrate a superb rate capability up to 10 C and a prolonged cycling of 1,600 cycles at 2 C with the per-cycle capacity decay of only 0.023%.This study paves the way for the ultimate deployment of lithium metal batteries in real-world applications that require fast charging and deep cycling.

关键词： graphene aerogel partial infusion fast-charging dendrite-free Li metal anodes