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Numerical study on ethylene-air continuous rotating detonation in annular combustors with different widths

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第5期23卷 388-404页

作者： wei-jie FAN wei-dong liu Hao-yang PENG Shi-jie liu Jian SUN Science and Technology on Scramjet Laboratory College of Aerospace Science and TechnologyNational University of Defense TechnologyChangsha 410073China State Key Laboratory of Aerospace Dynamic Satellite Control CenterXi’an 710043China

To investigate the impact of combustor width on continuous rotating detonation(CRD)fueled by ethylene and air,a series of 3 D simulations are conducted by changing the inner cylinder radius of an annular combustor while retaining the same outer cylinder *** results show that the CRD wave propagates more steadily and faster as the combustor width *** high-temperature zone at the backward-facing step preheats the propellants and contributes to the steady propagation of the CRD wave in 25-and 30-mm wide *** highest and the lowest velocities are obtained in the30-and 15-mm wide combustors at,respectively,1880.27 and 1681.01 m/*** the other hand,the average thrust decreases as the combustor width *** highest thrust is obtained in the 15-mm wide combustor while the lowest is in the 30-mm wide combustor,at 758.06 and 525.93 N,***,the thrust is much more stable in the 25-and 30-mm wide combustors than in the 15-and 20-mm wide combustors.

关键词： Continuous rotating detonation(CRD) Ethylene-air Combustor width Propagation mode Propulsive performance

New insights into the mechanism of surfactant enhanced oil recovery:Micellar solubilization and in-situ emulsification

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Petroleum Science 2022年第2期19卷 870-881页

作者： Xue-Zhi Zhao Guang-Zhi Liao Ling-Yan Gong Huo-Xin Luan Quan-Sheng Chen wei-dong liu dong liu Yu-Jun Feng Polymer Research Institute State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu610065People's Republic of China PetroChina Exploration&Production Company Beijing100007People's Republic of China Research Institute of Experiment and Detection Xinjiang Oilfield Branch CompanyPetroChinaKaramay834000People's Republic of China Research Institute of Petroleum Exploration&Development PetroChina Company LimitedBeijing100083People's Republic of China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang621000People's Republic of China

Reducing the oil-water interfacial tension(IFT)to ultra-low is believed the primary mechanism for surfactant-based enhanced oil recovery(EOR)***,field trials have shown that low concentration surfactant flooding can also improve oil recovery without ultra-low *** clarify the mechanism behind,the currently-used surfactant,naphthenic arylsulfonate(NAS),was used to unravel its function during surfactant flooding from the horizon of micron-and *** solubilization capacity of NAS micelle to petroleum fractions was evaluated through light absorbance strategy,smallangle neutron scattering,dynamic light scattering and transmission electron *** was found that micellar solubilization plays a significant role during the surfactant ***-situ emulsification was visualized in microfluidics with three types of microchips,respectively.A series of displacement tests were carried out with NAS solution pumping into oil-saturated *** results show that in-situ emulsification improve oil recovery mainly through blocking and entrainment *** from this work aid in understanding the interaction between surfactant solution and petroleum fractions at low surfactant concentration,which is helpful for design surfactant-based displacing system for EOR process.

关键词： Enhanced oil recovery Surfactant flooding Micellar solubilization Microfluidics In-situ emulsification

Flame quenching process in cavity based on model scramjet combustor

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Acta Mechanica Sinica 2012年第1期28卷 73-78页

作者： Yu Pan Jing Lei Jian-Han Liang wei-dong liu Zhen-Guo Wang Department of Aerospace and Material National University of Defense Technology410073 ChangshaChina

The flame quenching process in combustors was observed by high speed camera and Schlieren system, at the inflow conditions of Ma = 2.64, To = 1483K, P0 = 1.65 MPa, T = 724 K and P -- 76.3 kPa. Changing process of the flame and shock structure in the combustor was clearly observed. The results revealed that the precom- bustion shock disappeared accompanied with the process in which the flame was blown out and withdrawed from the mainflow into the cavity and vanished after a short while. The time of quenching process was extended by the cavity flame holder, and the ability of flame holding was enhanced by arranging more cavities in the downstream as well. The flame was blown from the upstream to the downstream, so the flame in the downstream of the cavity was quenched out later than that in the upstream.

关键词： Flame quenching process Cavity Model scramjet combustor

Experimental investigation of combustion mechanisms of kerosene-fueled scramjet engines with double-cavity flameholders

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Acta Mechanica Sinica 2011年第6期27卷 891-897页

作者： Yu Pan Jian-Guo Tan Jian-Han Liang wei-dong liu Zhen-Guo Wang Department of Aerospace and Material National University of Defense and Technology 410073 Changsha China

A scramjet combustor with double cavitybased flameholders was experimentally studied in a directconnected test bed with the inflow conditions of M = 2.64,Pt = 1.84 MPa,Tt = 1 300 *** ignition and selfsustained combustion with room temperature kerosene was achieved using pilot hydrogen,and kerosene was vertically injected into the combustor through 4×φ 0.5 mm holes mounted on the *** different equivalence ratios and different injection schemes with both tandem cavities and parallel cavities,flow fields were obtained and compared using a high speed camera and a Schlieren *** revealed that the combustor inside the flow field was greatly influenced by the cavity installation scheme,cavities in tandem easily to form a single side flame distribution,and cavities in parallel are more likely to form a joint flame,forming a choked combustion *** supersonic combustion flame was a kind of diffusion flame and there were two kinds of combustion *** the unchoked combustion mode,both subsonic and supersonic combustion regions *** in the choked mode,the combustion region was fully subsonic with strong shock propagating *** also showed that there was a balance point between the boundary separation and shock enhanced combustion,depending on the intensity of heat release.

关键词： Scramjet. Supersonic combustion. Flame structure Cavity flameholder

Convergence Rates of Tail Probabilities for Sums under Dependence Assumptions

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Acta Mathematica Sinica,English Series 2010年第8期26卷 1591-1600页

作者： Xiao Rong YANG wei dong liu Ke Ang FU Lin Xin ZHANG School of Statistics and Mathematics Zhejiang Gongshang University Hangzhou 310018 P. R. China Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China School of Statistics and Mathematics Zhejiang Gongshang University Han qzhou 310018 P. R. China

Let {X,X1,X2,……}be a zero mean strictly stationary Ф-mixing sequence. Set Sn=∑n k=1 and f（x^p）=∑∞n=1 n^r-2P（｜Sn｜≥x^p√ES2nlog n）,When ε〉（√2）1/p,for p〉1/2 and r〉1,the conditions for ∫∞ε f（x^p）dx 〈∞ to hold is established, by using coupled methods together withstrong approximation, which are different from the traditional symmetrization and Hoffman-JФrgensen inequality.

关键词： Complete convergence mixing sequences strong approximation

Changes in Spring Snow Cover over the Eastern and Western Tibetan Plateau and Their Associated Mechanism

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Advances in Atmospheric Sciences 2024年第5期41卷 959-973页

作者： Fangchi liu Xiaojing JIA wei dong Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province School of Earth SciencesZhejiang UniversityHangzhouZhejiang 310058China

The spring snow cover(SC)over the western Tibetan Plateau(TP)(TPSC)(W_TPSC)and eastern TPSC(E_TPSC)have displayed remarkable decreasing and increasing trends,respectively,during 1985–*** current work investigates the possible mechanisms accounting for these distinct TPSC *** results indicate that the decrease in W_TPSC is primarily attributed to rising temperatures,while the increase in E_TPSC is closely linked to enhanced *** circulation analysis shows that the essential system responsible for the TPSC changes is a significant anticyclonic system centered over the northwestern *** anomalous descending motion and adiabatic heating linked to this anticyclone leads to warmer temperatures and consequent snowmelt over the western ***,anomalous easterly winds along the southern flank of this anticyclone serve to transport additional moisture from the North Pacific,leading to an increase in snowfall over the eastern *** analysis reveals that the anomalous anticyclone is associated with an atmospheric wave pattern that originates from upstream *** warming of the subtropical North Atlantic(NA)sea surface temperature(SST)induces an atmospheric pattern resembling a wave train that travels eastward across the Eurasian continent before reaching the ***,the decline in winter sea ice(SIC)over the Barents Sea exerts a persistent warming influence on the atmosphere,inducing an anomalous atmospheric circulation that propagates southeastward and strengthens the northwest TP anticyclone in ***,an enhancement of subtropical stationary waves has resulted in significant increases in easterly moisture fluxes over the coastal areas of East Asia,which further promotes more snowfall over eastern TP.

关键词： snow cover Tibetan Plateau long-term changes spring

Down-regulation of Risa improves podocyte injury by enhancing autophagy in diabetic nephropathy

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Military Medical Research 2023年第1期10卷 32-44页

作者： Pei-Pei Su dong-wei liu Si-Jie Zhou Hang Chen Xian-Ming Wu Zhang-Suo liu Department of Nephrology the First Affiliated Hospital of Zhengzhou UniversityResearch Institutes of NephropathyZhengzhou UniversityZhengzhou 450052China Department of Nephrology and Rheumatology the Third People’s Hospital of ZhengzhouZhengzhou 450002China Henan Province Research Center for Kidney Disease Zhengzhou 450052China Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province Zhengzhou 450002China

Background: LncRNA AK044604(regulator of insulin sensitivity and autophagy, Risa) and autophagy-related factors Sirt1 and GSK3β play important roles in diabetic nephropathy(DN). In this study, we sought to explore the effect of Risa on Sirt1/GSK3β-induced podocyte ***: Diabetic db/db mice received Risa-inhibition adeno-associated virus(AAV) via tail vein injection, and intraperitoneal injection of lithium chloride(LiCl). Blood, urine, and kidney tissue samples were collected and analyzed at different time points. Immortalized mouse podocyte cells(MPCs) were cultured and treated with Risa-inhibition lentivirus(LV), EX-527, and LiCl. MPCs were collected under different stimulations as noted. The effects of Risa on podocyte autophagy were examined by qRT-PCR, Western blotting analysis, transmission electron microscopy,Periodic Acid-Schiff staining, and immunofluorescence ***: Risa and activated GSK3β were overexpressed, but Sirt1 was downregulated in DN mice and high glucosetreated MPCs(P<0.001, db/m vs. db/db, NG or HM vs. HG), which was correlated with poor prognosis. Risa overexpression attenuated Sirt1-mediated downstream autophagy levels and aggravated podocyte injury by inhibiting the expression of Sirt1(P<0.001, db/m vs. db/db, NG or HM vs. HG). In contrast, Risa suppression enhanced Sirt1-induced autophagy and attenuated podocyte injury, which could be abrogated by EX-527(P<0.001, db/db+Risa-AAV vs. db/db, HG+Risa-LV vs. HG). Furthermore, LiCl treatment could restore GSK3β-mediated autophagy of podocytes(P<0.001, db/db+LiCl vs. db/db, HG+LiCl vs. HG), suggesting that Risa overexpression aggravated podocyte injury by decreasing ***: Risa could inhibit autophagy by regulating the Sirt1/GSK3β axis, thereby aggravating podocyte injury in DN. Risa may serve as a therapeutic target for the treatment of DN.

关键词： Diabetic nephropathy LncRNA AK044604/Sirt1/GSK3β Autophagy

Auto-parametric resonance of a continuous-beam-bridge model under two-point periodic excitation:an experimental investigation and stability analysis

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 445-454页

作者： Li Yuchun Shen Chao liu wei Li dong Department of Hydraulic Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

The auto-parametric resonance of a continuous-beam bridge model subjected to a two-point periodic excitation is experimentally and numerically investigated in this *** auto-parametric resonance experiment of the test model is conducted to observe and measure the auto-parametric resonance of a continuous beam under a two-point excitation on *** parametric vibration equation is established for the test model using the finite-element *** auto-parametric resonance stability of the structure is analyzed by using Newmark's method and the energy-growth exponent *** effects of the phase difference of the two-point excitation on the stability boundaries of auto-parametric resonance are studied for the test *** with the experiment,the numerical instability predictions of auto-parametric resonance are consistent with the test phenomena,and the numerical stability boundaries of auto-parametric resonance agree with the experimental *** a continuous beam bridge,when the ratio of multipoint excitation frequency(applied to the columns)to natural frequency of the continuous girder is approximately equal to 2,the continuous beam may undergo a strong auto-parametric *** with the present experiment and analysis,a hypothesis of Volgograd Bridge's serpentine vibration is discussed.

关键词： auto-parametric resonance continuous beam bridge model two-point excitation experimental investigation stability analysis vibration of Volgograd Bridge

Data and Model Driven Task Offloading Strategy in the Dynamic Mobile Edge Computing System

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Journal of Systems Science & Complexity 2024年第1期37卷 351-368页

作者： dong Hairong WU wei SONG Haifeng liu Zhen ZHANG Zixuan School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China School of Electronic and Information Engineering BeiHang UniversityBeijing 100191China CRSC Research&Design Institute Group Co. Ltd.Beijing 100070China

Mobile Edge Computing(MEC)provides communication and computational capabilities for the industrial Internet,meeting the demands of latency-sensitive ***,traditional model-driven task offloading strategies face challenges in adapting to situations with unknown network communication status and computational *** limitation becomes notably significant in complex industrial networks of high-speed *** by these considerations,a data and model-driven task offloading problem is proposed in this paper.A redundant communication network is designed to adapt to anomalous channel states when tasks are offloaded to edge *** link switching mechanism is executed by the train according to the attributes of the completed *** task offloading optimization problem is formulated by introducing data-driven prediction of communication states into the traditional ***,the optimal strategy is achieved by employing the informer-based prediction algorithm and the quantum particle swarm optimization method,which effectively tackle real-time optimization problems due to their low time *** simulations illustrate that the data and model-driven task offloading strategy can predict the communication state in advance,thus reducing the cost of the system and improving its robustness.

关键词： Data driven model informer mobile edge computing quantum particle swarm optimization task offloading.