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Effects of P content in a P/HZSM-5 catalyst on the conversion of ethanol to hydrocarbons

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Journal of Natural Gas Chemistry 2011年第2期20卷 162-166页

作者： Jiangyin lu Yancong liu Key Laboratory of Oil and Gas Fine Chemicals of Ministry of Education Xinjiang University Urumqi 830046 Xinjiang China

A series of P/HZSM-5 catalysts prepared by impregnation method were used for ethanol conversion to lower olefins. The catalysts were characterized by X-ray diffraction （XRD）, NH3-temperature-programmed desorption （NH3-TPD） and N2 adsorption-desorption measurements. It was found that the P/HZSM-5 catalysts showed high activity and selectivity toward light olefins. The selectivities of propylene and butylene can be improved with the introduction of phosphorus （P）. When the content of P reached 3.0 wt%, more than 18.9% propylene in the gaseous products was obtained over the P/HZSM-5 catalyst at 450 ？C. The introduction of P modified the strong Br？nsted acid sites of the original HZSM-5 catalysts and P/HZSM-5 catalysts could resist coke formation and showed good stability.

关键词： ethanol P/HZSM-5 hydrocarbons modification

Atomization mechanism of a charged viscoelastic liquid sheet

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Chinese Journal of Aeronautics 2015年第2期28卷 403-409页

作者： liu lujia liu Yingjie lu Lipeng School of Astronautics Beihang University School of Energy and Power Engineering Beihang University

In order to study atomization mechanism of a viscoelastic liquid sheet in an electric field, the spatial-temporal stability analysis of a viscoelastic liquid sheet injected into a dielectric station- ary ambient gas in the presence of a vertical electric field is conducted. The dispersion relations of both sinuous and varicose disturbance modes are solved to explore the spatial-temporal instability of a charged viscoelastic sheet, by setting both the wave number and frequency complex. A para- metric study is performed to test the influence of the dimensionless parameters on the absolute instability of the sheet. The results show that the increase of liquid Weber number and time constant ratio, or decrease of gas to liquid density ratio and Reynolds number, can damp the absolute insta- bility. The effect of the liquid elasticity depends on the value of time constant ratio： when time con- stant ratio is small, the increase of liquid elasticity could amplify absolute growth rate, but the effect is weak when the elasticity number is relatively large; when time constant ratio is large, the increase of liquid elasticity cannot affect the absolute growth rate. Moreover, the variation of electrical Euler number can hardly influence the absolute instability of a charged viscoelastic sheet.

关键词： Absolute growth rate Absolute instability Electrified sheet Spatial-temporal instability Viscoelastic liquid

A contingency-aware method for N-2 security-constrained transmission expansion planning

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Journal of Modern Power Systems and Clean Energy 2019年第5期7卷 1008-1019页

作者： Dundun liu lu liu Haozhong CHENG Key Laboratory of Control of Power Transmission and Conversion Ministry of EducationShanghai Jiao Tong UniversityShanghai 200240China

In this paper,a novel contingency-aware method for N-2 security-constrained transmission expansion planning is *** ensure that the transmission construction plan satisfies the N-2 security criterion,the proposed method takes advantage of the adjustable robust optimization(ARO)framework and upgrades *** construct a discrete uncertainty set in which component failures are treated as uncertain events that are handled as binary *** addition to the failure of existing lines and generators,we explicitly model the failure of candidate *** proposed model comprises a master problem that makes the transmission construction decision,and a series of subproblems that can detect not only the worst contingency,but also the potential *** studies on the IEEE RTS 24-bus and IEEE 118-bus test systems are carried out to validate the effectiveness of the proposed *** with the deterministic method and ARO method in the literature,the proposed method has higher computational efficiency.

关键词： Contingency N-2 security Robust optimization Transmission expansion planning

Different Impacts of Intraseasonal Oscillations on Precipitation in Southeast China between Early and Late Summers

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Advances in Atmospheric Sciences 2022年第11期39卷 1885-1896页

作者： Junqi liu Riyu lu State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100029China

This study investigates the influences of boreal summer intraseasonal oscillation(BSISO), which originates from the equatorial Indian Ocean and prevails over the Indo-Pacific region, on precipitation over Southeast China, including South China and Yangtze River Valley. The results indicate that the BSISO-related precipitation anomalies are remarkably different between early summer(May–June) and late summer(July–August). The BSISO-related precipitation anomalies tend to appear more northward in late summer in comparison with early summer. Accordingly, the BSISO is significantly related to precipitation anomalies over South China during many phases in early summer but related to very weak anomalies during all the phases in late summer. Such northward shifts of precipitation anomalies from early summer to late summer are clearest during phases 4 and 7, when the lower-tropospheric anticyclonic and cyclonic circulation anomalies dominate over the subtropical western North Pacific, respectively. Finally, we explain the differences between early and late summers through the seasonal northward migration of climatological equivalent potential temperature gradient, which is located in the South China during early summer but migrates northward to the YRV during late summer.

关键词： intraseasonal oscillation precipitation Southeast China

Examining El Nio in the Holocene: implications and challenges

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National Science Review 2018年第6期5卷 807-809页

作者： Zhengyao lu Zhengyu liu Department of Physical Geography and Ecosystem Science Lund University Department of Geography Ohio State University

The El Nio–Southern Oscillation(ENSO) is characterized by year-to-year anomalous surface climate variability over the tropical Pacific. Through atmospheric teleconnections, ENSO can bring droughts and floods worldw... 详细信息

关键词： Examining El Ni implications and challenges o in the Holocene El

EA-DFPSO:An intelligent energy-efficient scheduling algorithm for mobile edge networks

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Digital Communications and Networks 2022年第3期8卷 237-246页

作者： Yao lu lu liu Jiayan Gu John Panneerselvam Bo Yuan School of Informatics University of LeicesterUniversity RoadLeicesterLE17RHUnited Kingdom School of Computing and Engineering University of DerbyKedleston RoadDerbyDE221GBUnited Kingdom

Cloud data centers have become overwhelmed with data-intensive applications due to the limited computational capabilities of mobile *** edge computing is emerging as a potential paradigm to host application execution at the edge of networks to reduce transmission *** nodes are usually distributed in edge environments,enabling crucially efficient task scheduling among those nodes to achieve reduced processing ***,it is imperative to conserve edge server energy,enhancing their *** this end,this paper proposes a novel task scheduling algorithm named Energy-aware Double-fitness Particle Swarm Optimization(EA-DFPSO)that is based on an improved particle swarm optimization algorithm for achieving energy efficiency in an edge computing environment along with minimal task execution *** proposed EA-DFPSO algorithm applies a dual fitness function to search for an optimal tasks-scheduling scheme for saving edge server energy while maintaining service quality for *** experimentation demonstrates that our proposed EA-DFPSO algorithm outperforms the existing traditional scheduling algorithms to achieve reduced task completion time and conserve energy in an edge computing environment.

关键词： Mobile edge computing Energy-aware systems Task scheduling Heuristic algorithms

A flexible multiscale algorithm based on an improved smoothed particle hydrodynamics method for complex viscoelastic flows

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1387-1402页

作者： Jinlian REN Peirong lu Tao JIANG Jianfeng liu Weigang lu College of Mathematical Science Yangzhou UniversityYangzhou 225002Jiangsu ProvinceChina College of Hydraulic Science and Engineering Yangzhou UniversityYangzhou 225002Jiangsu ProvinceChina

Viscoelastic flows play an important role in numerous engineering fields,and the multiscale algorithms for simulating viscoelastic flows have received significant attention in order to deepen our understanding of the nonlinear dynamic behaviors of viscoelastic ***,traditional grid-based multiscale methods are confined to simple viscoelastic flows with short relaxation time,and there is a lack of uniform multiscale scheme available for coupling different solvers in the simulations of viscoelastic *** this paper,a universal multiscale method coupling an improved smoothed particle hydrodynamics(SPH)and multiscale universal interface(MUI)library is presented for viscoelastic *** proposed multiscale method builds on an improved SPH method and leverages the MUI library to facilitate the exchange of information among different solvers in the overlapping *** test the capability and flexibility of the presented multiscale method to deal with complex viscoelastic flows by solving different multiscale problems of viscoelastic *** the first example,the simulation of a viscoelastic Poiseuille flow is carried out by two coupled improved SPH methods with different spatial *** effects of exchanging different physical quantities on the numerical results in both the upper and lower domains are also investigated as well as the absolute errors in the overlapping *** the second example,the complex Wannier flow with different Weissenberg numbers is further simulated by two improved SPH methods and coupling the improved SPH method and the dissipative particle dynamics(DPD)*** numerical results show that the physical quantities for viscoelastic flows obtained by the presented multiscale method are in consistence with those obtained by a single solver in the overlapping ***,transferring different physical quantities has an important effect on the numerical results.

关键词： multiscale method improved smoothed particle hydrodynamics(SPH) dissipative particle dynamics(DPD) multiscale universal interface(MUI) complex viscoelastic flow

Heat transfer characterization and improvement in an external catalyst cooler fluidized bed

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Particuology 2021年第3期19卷 103-112页

作者： Jiantao Li Xiuying Yao lu liu Xudong Zhong Chunxi lu State Key Laboratory of Heavy Oil China University of Petroleum(Beijing)Beijing 102249China luoyang R&D Center of Technology SINOPEC Engineering(Group)Co.Ltd.Luoyang 471003China

Gas-solid fluidized beds have been widely used in heat transfer processes,and so there have been many studies focused on increasing heat transfer in such *** the present work,a pilot scale cold mode experimental rig was constructed to assess the effects of hydrodynamics on bed-to-wall heat transfer and to investigate various means of enhancing heat transfer in a dense gas-solid fluidized bed with external solid *** experimental results show that heat transfer in the dense region played a dominant role in total bed-to-wall heat transfer,accounting for more than 88%of the total heat transfer *** transfer could be lowered as a result of solids bypass that occurred because of external solids circulation,but this effect was weakened by the radial mixing of *** heat transfer characteristics identified in this study indicate that a specially designed baffle can be used to enhance bed-to-wall heat *** installing such baffles in the fluidized bed test structure,a 70%increase in the total heat transfer coefficient was obtained.

关键词： Gas-solid fluidized bed Heat transfer Hydrodynamics Baffles Intensification

Multiscale tensegrity model for the tensile properties of DNA nanotubes

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Applied Mathematics and Mechanics(English Edition) 2023年第3期44卷 397-410页

作者： Hanlin liu Nenghui ZHANG Wei lu Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Qishuyan Senior High School of Changzhou Changzhou 213000Jiangsu ProvinceChina

DNA nanotubes(DNTs)with user-defined shapes and functionalities have potential applications in many *** far,compared with numerous experimental studies,there have been only a handful of models on the mechanical properties of such *** paper aims at presenting a multiscale model to quantify the correlations among the pre-tension states,tensile properties,encapsulation structures of DNTs,and the surrounding ***,by combining a statistical worm-like-chain(WLC)model of single DNA deformation and Parsegian's mesoscopic model of DNA liquid crystal free energy,a multiscale tensegrity model is established,and the pre-tension state of DNTs is characterized theoretically for the first ***,by using the minimum potential energy principle,the force-extension curve and tensile rigidity of pre-tension DNTs are ***,the effects of the encapsulation structure and surrounding factors on the tensile properties of DNTs are *** predictions for the tensile behaviors of DNTs can not only reproduce the existing experimental results,but also reveal that the competition of DNA intrachain and interchain interactions in the encapsulation structures determines the pre-tension states of DNTs and their tensile *** changes in the pre-tension states and environmental factors make the monotonic or non-monotonic changes in the tensile properties of DNTs under longitudinal loads.

关键词： DNA nanotube(DNT) multiscale model tensegrity structure pre-tension state tensile property