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Dehydrogenation of n-butane over vanadia catalysts supported on silica gel

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Journal of Natural Gas Chemistry 2009年第1期18卷 88-93页

作者： Yuebing xu Jiangyin Lu Mei zhong Jide Wang Key Laboratory of Oil ＆ Gas Fine Chemicals Ministry of Education Xinjiang University 14# Shengli Road Urumqi 830046 Xinjiang China

VOx/SiO2 catalysts prepared by impregnation method were used for catalytic dehydrogenation of n-butane to butenes and characterized by X-ray diffraction, FT-IR, UV-vis, Raman, and BET measurements. The effects of VOx loading and the reaction temperature on the VOx/SiO2 catalysts and their catalytic performances for the dehydrogenation of n-butane were studied. When the VOx loading was 12% g/gcat and reaction temperature was between 590 ℃ and 600℃, n-butane conversion and butenes yields reached the highest value under H2 flux of 10 ml/min and n-butane flux of 10 ml/min. Product distribution, such as the ratio of 2-butene to 1-butene and the ratio of cis-2-butene to trans-2-butene, was mainly influenced by the reaction temperature.

关键词： n-butane catalytic dehydrogenation butene VOx supported SiO2

Enhanced exergy cost optimization of operating conditions in FCCU main fractionator

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Chinese Journal of Chemical Engineering 2018年第8期26卷 1750-1757页

作者： Chonglin zhong Yi Zheng Shenghu xu Shaoyuan Li Department of Automation Shanghai Jiao Tong UniversityKey Laboratory of System Control and Information ProcessingMinistry of EducationShanghai 200240China SinopecJiujiang Branch Corporation Jiufiang 332004China

Exergy indicates the maximal energy that can do work effectively. Different from optimization of product quality or calculation of generic energy conservation in most previous studies, the application of exergy analysis and exergy cost optimization in petrochemical industry is of great economic and environmental significance. Based on the main fractionator in Jiujiang Petrochemical Complex No. 2 FCCU, an enhanced exergy cost optimization under different operating conditions by adjusting set points of temperature and valves opening degree for flow control is studied in this paper in order to reduce exergy cost and improve the quality of energy. A steadystate optimization algorithm to enhance exergy availability and an objective function comprehensively considering exergy loss are proposed. On the basis of ensuring the quality of petroleum products, the economic benefits can be improved by optimizing the controllable variables due to the fact that exergy cost is decreased.

关键词： Exergy Optimization of operating conditions Fractionator FCCU Exergy Cost

Multi-objective optimization of p-xylene oxidation process using an improved self-adaptive differential evolution algorithm

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Chinese Journal of Chemical Engineering 2017年第8期25卷 983-991页

作者： Lili Tao Bin xu Zhihua Hu Weimin zhong College of Engineering Shanghai Polytechnic University School of Mechanical Engineering Shanghai University of Engineering Science Key Laboratory of Advanced Control and Optimization for Chemical Processes Ministry of Education East China University of Science and Technology

The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid （TPA）. The liquid-phase catalytic oxidation of p-xylene （PX） to TPA is regarded as a critical and efficient chemical process in industry [ 1 ]. PX oxidation reaction involves many complex side reactions, among which acetic acid combustion and PX combustion are the most important. As the target product of this oxidation process, the quality and yield of TPA are of great concern. However, the improvement of the qualified product yield can bring about the high energy consumption, which means that the economic objectives of this process cannot be achieved simulta- neously because the two objectives are in conflict with each other. In this paper, an improved self-adaptive multi-objective differential evolution algorithm was proposed to handle the multi-objective optimization prob- lems. The immune concept is introduced to the self-adaptive multi-objective differential evolution algorithm （SADE） to strengthen the local search ability and optimization accuracy. The proposed algorithm is successfully tested on several benchmark test problems, and the performance measures such as convergence and divergence metrics are calculated. Subsequently, the multi-objective optimization of an industrial PX oxidation process is carried out using the proposed immune self-adaptive multi-objective differential evolution algorithm （ISADE）. Optimization results indicate that application oflSADE can greatly improve the yield of TPA with low combustion loss without degenerating TA quality.

关键词： p-Xylene oxidation Operation condition optimization Multi-objective optimization Self-adaptive differential evolution

Development of a New-Type Multiple-Source Heat Pump with Two-Stage Compression

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Journal of Thermal Science 2019年第4期28卷 635-642页

作者： zhong Xiaohui YANG Hailong YANG Ke xu Jianzhong Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China College of Metallurgy and Energy North China University of Science and TechnologyTangshan 063009China

A new-type multiple-source heat pump cycle with two-stage compression was established on the basis of the problems of similarly existing heat *** equivalent temperature levels of typical evaporators are applied to the different heat sources of the proposed cycle,and the high-temperature heat sources are shown to enhance vapor ***,the mathematical model and prototype are developed,and the results from experimental simulation and validation showed that the solar collector can improve the heating performance of the proposed heat pump *** the middle-temperature heating period,the outdoor temperature is less than-25℃,and the average coefficient of performance(COP)value of the proposed heat pump was 4.2,which was greater than the COPs of conventional ground source heat pumps.

关键词： multiple-source heat pump two-stage compression solar collector simulation

Decentralized attitude synchronization tracking control for multiple spacecraft under directed communication topology

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Chinese Journal of Aeronautics 2016年第4期29卷 995-1006页

作者： Zheng zhong xu Ying Zhang Lisong Song Shenmin College of Astronautics Nanjing University of Aeronautics and Astronautics Science and Technology on Information System Engineering Laboratory Jiangxi Ship Sailing Instrument Co.Ltd Center for Control Theory and Guidance Technology Harbin Institute of Technology

This paper studies the attitude synchronization tracking control of spacecraft formation flying with a directed communication topology and presents three different controllers. By introducing a novel error variable associated with rotation matrix, a decentralized attitude synchronization controller, which could obtain almost global asymptotical stability of the closed-loop system, is developed. Then, considering model uncertainties and unknown external disturbances, we propose a robust adaptive attitude synchronization controller by designing adaptive laws to estimate the unknown parameters. After that, the third controller is proposed by extending this method to the case of time-varying communication delays via Lyapunov-Krasovskii analysis. The distinctive feature of this work is to address attitude coordinated control with model uncertainties, unknown disturbances and time-varying delays in a decentralized framework, with a strongly connected directed information flow. It is shown that tracking and synchronization of an arbitrary desired attitude can be achieved when the stability condition is satisfied. Simulation results are provided to demonstrate the effectiveness of the proposed control schemes. (C) 2016 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY-NC-ND license.

关键词： Attitude synchronization Directed topology Lyapunov stability Spacecraft formation Time delays

Structure of human lysine methyltransferase Smyd2 reveals insights into the substrate divergence in Smyd proteins

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Journal of Molecular Cell Biology 2011年第5期3卷 293-300页

作者： Shutong xu Chen zhong Tianlong Zhang Jianping Ding State Key Laboratory of Molecular Biology and Research Center for Structural Biology Institute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesChinese Academy of SciencesShanghai 200031China Graduate School of Chinese Academy of Sciences 320 YueYang RoadShanghai 200031China

The SET-and myeloid-Nervy-DEAF-1(MYND)-domain containing(Smyd)lysine methyltransferases 1–3 share relatively high sequence similarity but exhibit divergence in the substrate *** we report the crystal structure of the full-length human Smyd2 in complex with S-adenosyl-L-homocysteine(AdoHcy).Although the Smyd1–3 enzymes are similar in the overall structure,detailed comparisons demonstrate that they differ substantially in the potential substrate-binding *** binding site of Smyd3 consists mainly of a deep and narrow pocket,while those of Smyd1 and Smyd2 consist of a comparable pocket and a long *** addition,Smyd2,which has lysine methyltransferase activity on histone H3-lysine 36,exhibits substantial differences in the wall of the substrate-binding pocket compared with those of Smyd1 and Smyd3 which have activity specifically on histone H3-lysine *** differences in the substrate-binding site might account for the observed divergence in the specificity and methylation state of the *** modeling study of Smyd2 in complex with a p53 peptide indicates that mono-methylation of p53-Lys372 might result in steric conflict of the methyl group with the surrounding residues of Smyd2,providing a structural explanation for the inhibitory effect of the SET7/9-mediated mono-methylation of p53-Lys372 on the Smyd2-mediated methylation of p53-Lys370.

关键词： Smyd2 Smyd proteins SET family histone lysine methyltransferase epigenetics

An improved lumped parameter model predicting attenuation of earmuff with air leakage

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Chinese Physics B 2022年第11期31卷 364-370页

作者： xu zhong Zhe Chen Dong Zhang Key Laboratory of Modern Acoustics Institute of AcousticsNanjing UniversityNanjing 210093China

Since air leakage is inevitable when earmuffs are worn improperly or together with safety glasses in factory or military,it is required to be considered to accurately predict earmuff *** unwanted air leakage,under controlled air leakage is introduced to earmuff to achieve adjustable attenuations in different signal-to-noise ratios(SNRs)and balance between attenuation and speech *** work is to develop an improved lumped parameter model(LPM)to predict earmuff attenuation with consideration of air *** leakage paths are introduced into conventional LPM without air leakage,and air leakage path impedance is analytically described by Maa’s microperforated tube *** passive attenuation behavior can be analytically described and analyzed with the improved ***,the validity of improved LPM is verified *** results indicate that the improved LPM can predict earmuff attenuation with air leakage,and air leakage deteriorates earmuff attenuation and turns resonance frequency higher.

关键词： earmuff lumped parameter model air leakage attenuation

Hybrid Model of Molten Steel Temperature Prediction Based on Ladle Heat Status and Artificial Neural Network

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Journal of Iron and Steel Research International 2014年第2期21卷 181-190页

作者： Fei HE Dong-feng HE An-jun xu Hong-bing WANG nai-yuan TIAN School of Metallurgical and Ecological Engineering University of Science and Technology Beijing State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Computer and Communication Engineering University of Science and Technology Beijing

Aiming at the characteristics of the practical steelmaking process, a hybrid model based on ladle heat sta- tus and artificial neural network has been proposed to predict molten steel temperature. The hybrid model could over- come the difficulty of accurate prediction using a single mathematical model, and solve the problem of lacking the consideration of the influence of ladle heat status on the steel temperature in an intelligent model. By using the hybrid model method, forward and backward prediction models for molten steel temperature in steelmaking process are es- tablished and are used in a steelmaking plant. The forward model, starting from the end-point of BOF, predicts the temperature in argon-blowing station, starting temperature in LF, end temperature in LF and tundish temperature forwards, with the production process evolving. The backward model, starting from the required tundish tempera- ture, calculates target end temperature in LF, target starting temperature in LF, target temperature in argon-blo- wiag station and target BOF end-point temperature backwards. Actual application results show that the models have better prediction accuracy and are satisfying for the process of practical production.

关键词： steelmaking process hybrid model ladle heat status neural network molten steel temperature prediction

Improved flotation performance of hematite fines using citric acid as a dispersant

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International Journal of Minerals,Metallurgy and Materials 2016年第10期23卷 1119-1125页

作者： Xi-mei Luo Wan-zhong Yin Chuan-yao Sun nai-ling Wang Ying-qiang Ma Yun-fan Wang State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming University of Science and Technology Kunming 650093 China Faculty of Land and Resource Engineering Kunming University of Science and Technology Kunming 650093 China College of Zijin Mining Fuzhou University Fuzhou 350116 China College of Resources and Civil Engineering Northeastem University Shenyang 110819 China Beijing General Research Institute of Mining and Metallurgy Beijing 100044 China Faculty of Minerals Processing and Bioengineering Central South University Changsha 410083 China

In this study, citric acid was used as a dispersant to improve the flotation performance of hematite fines. The effect and mechanism of citric acid on the reverse flotation of hematite fines were investigated by flotation tests, sedimentation experiments, scanning electron microscopy（SEM）, zeta-potential measurements, and X-ray photoelectron spectroscopy（XPS）. The results of SEM analysis and flotation tests reveal that a strong heterocoagulation in the form of slime coating or coagulation in hematite fine slurry affects the beneficiation of hematite ores by froth flotation. The addition of a small amount of citric acid（less than 300 g/t） favorably affects the reverse flotation of hematite fines by improving particle dispersion. The results of sedimentation experiments, zeta-potential measurements, and XPS measurements demonstrate that citric acid adsorbs onto hematite and quartz surfaces via hydrogen bonding, thereby reducing the zeta potentials of mineral surfaces, strengthening the electrical double-layer repulsion between mineral particles, and dispersing the pulp particles.

关键词： hematite citric acid dispersion flotation hydrogen bonding