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Experimental research on the instability propagation characteristics of liquid kerosene rotating detonation wave

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Defence Technology（防务技术） 2020年第6期16卷 1106-1115页

作者： Quan Zheng hao-long Meng Chun-sheng weng Yu-wen Wu wen-kang Feng Ming-liang Wu National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing210094China

In order to study the instability propagation characteristics of the liquid kerosene rotating detonation wave(RDW),a series of experimental tests were carried out on the rotating detonation combustor(RDC)with *** fuel and oxidizer are room-temperature liquid kerosene and preheated oxygenenriched air,*** experimental tests keep the equivalence ratio of 0.81 and the oxygen mass fraction of 35%unchanged,and the total mass flow rate is maintained at about 1000 g/s,changing the total temperature of the oxygen-enriched air from 620 K to 860 *** different types of instability were observed in the experiments:temporal and spatial instability,mode transition and *** interaction between RDW and supply plenum may be the main reason for the fluctuations of detonation wave velocity and pressure peaks with ***,the inconsistent mixing of fuel and oxidizer at different circumferential positions is related to RDW oscillate *** phenomenon of single-double-single wave transition is *** the transition,the initial RDW weakens until disappears,and the compression wave strengthens until it becomes a new RDWand propagates *** increased deflagration between the detonation products and the fresh gas layer caused by excessively high temperature is one of the reasons for the RDC quenching and re-initiation.

关键词： Rotating detonation wave Liquid kerosene Oxygen-enriched air Instability propagation characteristics Compression wave

Existence and Uniqueness of Positive Solutions for a Class of Semilinear Elliptic Systems

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Acta Mathematica Sinica,English Series 2011年第6期27卷 1079-1090页

作者： Ren hao CUI Jun Ping SHI Yu wen WANG Y. Y. Tseng Functional Analysis Research Center and School of Mathematical Sciences Harbin Normal University Harbin 150025 P. R. China Department of Mathematics College of William and Mary Williamsburg Virginia 23187-8795 USA

The authors prove the uniqueness and existence of positive solutions for the semilinear elliptic system which involves nonlinearities with sublinear growth conditions.

关键词： Semilinear elliptic systems positive solution existence uniqueness

Localized Optical Waves in Defocusing Regime of Negative-Index Materials

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Chinese Physics Letters 2017年第10期34卷 8-12页

作者： wen-hao Xu Zhan-Ying Yang Chong Liu wen-Li Yang School of Physics Northwest University Xi'an 710069 Shaanxi Key Laboratory for Theoretical Physics Frontiers Xi'an 710069 Institute of Modern Physics Northwest University Xi'an 710069

We study optical localized waves on a plane-wave background in negative-index materials governed by the defocusing nonlinear Schr6dinger equation with self-steepening effect. Important characteristics of localized waves, such as the excitations, transitions, propagation stability, and mechanism, are revealed in detail. An intrigu- ing sequential transition that involves the rogue wave, antidark-dark soliton pair, antidark soliton and antidark soliton pair can be triggered as the self-steepening effect attenuates. The corresponding phase diagram is estab- lished in the defocusing regime of negative-index materials. The propagation stability of the localized waves is confirmed numerically. In particular, our results illuminate the transition mechanism by establishing the exact correspondence between the transition and the modulation instability analysis.

关键词： In Localized Optical Waves in Defocusing Regime of Negative-Index Materials

Study on denoising of continuous spectrum on-line monitoring signal of water quality with micro-reagents based on HHT

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Optoelectronics Letters 2022年第2期18卷 115-121页

作者： LI wen LÜ Binbin FU hao CAI Yongqing Institute of Mechanical and Electrical Engineering North China University of TechnologyBeijing 100144China

A continuous spectrum water quality on-line monitoring signal processing method based on Hilbert-Huang transform(HHT) is proposed in this paper, which combines the micro-reagent water quality on-line monitoring technology of sequential injection. The modulation signal and spectrum curve of each intrinsic mode function(IMF) component of the original spectrum signal were obtained by empirical mode decomposition(EMD). The water sample data of different concentrations in the continuous spectrum on-line monitoring system was analyzed by the HHT model. The noise signal was excavated to realize the noise reduction processing, and the reconstruction of the continuous spectrum signal was realized after the noise reduction processing was completed. The research results show that this method can effectively reduce the noise of continuous spectrum signals according to different signal-to-noise characteristics of continuous spectrum, and has convenient use, fast processing speed, and high resolution in the time-frequency domain, which effectively improves the stability and accuracy of the micro-reagent continuous spectrum water quality on-line monitoring system.

关键词： signal spectrum continuous

Variations in aeolian landform patterns in the Gonghe Basin over the last 30 years

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Journal of Mountain Science 2021年第8期18卷 2034-2047页

作者： QI Yu-han PAN Mei-hui hao Ze-wen YANG An-na XUE wen-xuan College of Geography and Environment Science Northwest Normal UniversityLanzhou730070China

Wind erosion,or the transportation and deposition of sand into desert dunes and aeolian loess,is one of the most important aeolian *** progression of aeolian landforms expands arid and barren landscapes,leading to the degradation of adjacent *** Gonghe Basin,as a typical plateau with abundant sand sources,is highly sensitive to changes in the local climate *** order to quantify the spatial-temporal variations in the aeolian landforms in the Gonghe Basin,we conducted field surveys and also analyzed twelve remote sensing(Landsat5 TM and Landsat8 OLI)images that sample the Gonghe Basin from 1989 to *** the Gonghe Basin,we identified aeolian landforms such as climbing dunes on the windward slopes of the foothills,checkerboard dunes in the southeastern part of the basin,flat dunes,parabolic dunes and crescent dunes on the east and west sides of Longyangxia Reservoir,shrubby sandbanks on the valley slope in Shazhuyu,Tanggemu,and Indel,and sandy thickets at the bottom of the valley near the Dalian Sea,the Longyangxia Reservoir,and the tributaries of the Yellow *** 1989 to 2005,the area of the aeolian regions expanded by 816.7 km2,with an annual conversion rate of 0.05%.From 2015 to 2019,the area of the aeolian regions shrunk by 2411.9 km2,with an annual conversion rate of−0.15%.The number and size of the fixed and semi-fixed dunes(*** shrubby sandbanks on the valley slope and the sandy thickets at the bottom of the valley)were more stable than those of the mobile dunes(*** checkerboard dunes,the flat dunes,the crescent dunes,the parabolic dunes,and the climbing dunes).The fixed and semi-fixed dunes were arranged in an irregular ring shape,and the location of the center of gravity of this ring did not change significantly from 1989 to 2019;in this time,the mobile dunes migrated to the northwest.

关键词： Gonghe Basin Spatial-temporal variation Aeolian processes Remote sensing interpretation

Heteroatom-Induced Accelerated Kinetics on Nickel Selenide for Highly Efficient Hydrazine-Assisted Water Splitting and Zn-Hydrazine Battery

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Nano-Micro Letters 2023年第9期15卷 492-504页

作者： hao-Yu Wang Lei Wang Jin-Tao Ren wen-wen Tian Ming-Lei Sun Zhong-Yong Yuan School of Materials Science and Engineering Smart Sensing Interdisciplinary Science CenterNankai UniversityTianjin 300350People’s Republic of China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071People’s Republic of China

Hydrazine-assisted water electrolysis is a promising energy conversion technology for highly efficient hydrogen *** design of bifunctional electrocatalysts,which can simultaneously accelerate hydrogen evolution reaction(HER)/hydrazine oxidation reaction(HzOR)kinetics,is the key ***,we demonstrate the development of ultrathin P/Fe co-doped NiSe_(2) nanosheets supported on modified Ni foam(P/Fe-NiSe_(2)) synthesized through a facile electrodeposition process and subsequent heat *** on electrochemical measurements,characterizations,and density functional theory calculations,a favorable“2+2”reaction mechanism with a two-step HER process and a two-step HzOR step was fully proved and the specific effect of P doping on HzOR kinetics was investigated.P/Fe-NiSe_(2) thus yields an impressive electrocatalytic performance,delivering a high current density of 100 mA cm^(−2) with potentials of−168 and 200 mV for HER and HzOR,***,P/Fe-NiSe_(2) can work efficiently for hydrazine-assisted water electrolysis and Zn-Hydrazine(Zn-Hz)battery,making it promising for practical application.

关键词： Water electrolysis Hydrogen production Hydrazine oxidation Bifunctional electrocatalyst Heteroatom doping

SYSTEM FOR AUTOMATIC GENERALIZATION OF TOPOGRAPHIC MAPS

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Chinese Geographical Science 2006年第2期16卷 165-170页

作者： YAN hao-wen LI Zhi-lin AI Ting-hua School of Mathematics Physics and Software Engineering Lanzhou Jiaotong University Lanzhou 730070 19. R. China GIS Division Department of Geography University of Zurich Zurich Switzerland Department of Land Surveying ancl Geo-lnformatics the Hong Kong Polytechnic University Hong Kong P. R. China School of Resource and Environment Science Wuhan University Wuhan 430079 P. R. China

With the construction of spatial data infi＇astructure, automated topographic map generalization becomes an indispensable component in the community of cartography and geographic information science. This paper describes a topographic map generalization system recently developed by the authors. The system has the following characteristics： 1） taking advantage of three levels of automation, i.e. fully automated generalization, batch generalization, and interactive generalization, to undertake two types of processes, i.e. intelligent inference process and repetitive operation process in generalization; 2） making use of two kinds of sources for generalizing rule library, i.e. written specifications and cartographers＇ experiences, to define a six-element structure to describe the rules; 3） employing a hierarchical structure for map databases, logically and physically; 4） employing a grid indexing technique and undo/redo operation to improve database retrieval and object generalization efficiency. Two examples of topographic map generalization are given to demonstrate the system. It reveals that the system works well. In fact, this system has been used for a number of projects and it has been found that a great improvement in efficiency compared with traditional map general- ization process can be achieved.

关键词： map generalization system map database rule library topographic map

A new interacting capillary bundle model on the multiphase flow in micropores of tight rocks

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Petroleum Science 2024年第2期21卷 1099-1112页

作者： wen-Quan Deng Tian-Bo Liang wen-Zhong Wang hao Liu Jun-Lin Wu Fu-Jian Zhou National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China

Surfactants are widely used in the fracturing fluid to enhance the imbibition and thus the oil recovery rate. However, current numerical models cannot capture the physics behind capillary imbibition during the wettability alteration by surfactants. Although the interacting capillary bundle(ICB) model shows potential in characterizing imbibition rates in different pores during wettability alteration, the existing ICB models neglect the influence of wettability and viscosity ratio on the imbibition behavior, making it difficult to accurately describe the oil-water imbibition behavior within the porous media. In this work,a new ICB mathematical model is established by introducing pressure balance without assuming the position of the leading front to comprehensively describe the imbibition behavior in a porous medium under different conditions, including gas-liquid spontaneous imbibition and oil-water *** the pore size distribution of a tight rock is known, this new model can predict the changes of water saturation during the displacement process in the tight rock, and also determine the imbibition rate in pores of different sizes. The water saturation profiles obtained from the new model are validated against the waterflooding simulation results from the CMG, while the imbibition rates calculated by the model are validated against the experimental observations of gas-liquid spontaneous imbibition. The good match above indicates the newly proposed model can show the water saturation profile at a macroscopic scale while capture the underlying physics of the multiphase flow in a porous medium at a microscopic scale. Simulation results obtained from this model indicate that both wettability and viscosity ratio can affect the sequence of fluid imbibition into pores of different sizes during the multiphase flow, where less-viscous wetting fluid is preferentially imbibed into larger pores while more-viscous wetting fluid tends to be imbibed into smaller pores. Fur

关键词： Imbibition Multiphase flow Tight rock Interacting capillary bundle model Wettability

Orbital evolution of a planet with tidal dissipation in a restricted three-body system

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Research in Astronomy and Astrophysics 2019年第9期19卷 79-96页

作者： wen-Lei Wang Xue-Qing Xu Xin-hao Liao Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai200030China Key Laboratory of Planetary Sciences Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai200030China University of Chinese Academy of Sciences Beijing100049China

The angle between planetary spin and the normal direction of an orbital plane is supposed to reveal a range of information about the associated planetary formation and evolution. Since the orbit’s eccentricity and inclination oscillate periodically in a hierarchical triple body and tidal friction makes the spin parallel to the normal orientation of the orbital plane with a short timescale in an isolated binary system, we focus on the comprehensive effect of third body perturbation and tidal mechanism on the angle. Firstly, we extend the Hut tidal model(1981) to the general spatial case, adopting the equilibrium tide and weak friction hypothesis with constant delay time, which is suitable for arbitrary eccentricity and any angle ? between the planetary spin and normal orientation of the orbital plane. Furthermore, under the constraint of angular momentum conservation, the equations of orbital and ratational motion are given. Secondly, considering the coupled effects of tidal dissipation and third body perturbation, and adopting the quadrupole approximation as the third body perturbation effect, a comprehensive model is established by this work. Finally, we find that the ultimate evolution depends on the timescales of the third body and tidal friction. When the timescale of the third body is much shorter than that of tidal friction, the angle ? will oscillate for a long time,even over the whole evolution;when the timescale of the third body is observably larger than that of the tidal friction, the system may enter stable states, with the angle ? decaying to zero ultimately, and some cases may have a stable inclination beyond the critical value of Lidov-Kozai resonance. In addition, these dynamical evolutions depend on the initial values of the orbital elements and may aid in understanding the characteristics of the orbits of exoplanets.

关键词： astrometry and celestial mechanics:celestial mechanics planet-star interactions planets and satellites:dynamical evolution and stability