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Influence of fuel injection position and equivalent mixture ratio on chemical non-equilibrium effects of single expansion ramp nozzle

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航空动力学报 2013年第9期28卷 2100-2111页

作者： cheng cheng WANG Yi-bai LIU yu QIN Li-zi School of Astronautics Beijing University of Aeronautics and Astronautics

Chemical non-equilibrium flow was investigated for the scramjet single expansion ramp nozzle(SERN)with a strut-based liquid-kerosene-fueled ***-dimensional Reynolds-averaged NavierStokes(RANS)equations were solved with the species conservation equation for continuous phase and the renormalization group(RNG)k-εturbulence *** discrete-phase model was analyzed for liquidkerosene droplets behavior in the supersonic *** was simulated by kerosene surrogate fuel's10-species and 13-step reduced reaction kinetics mechanism with use of Arrhenius's laminar finite rate *** studies were carried out to estimate the influence of different fuel injection positions and equivalent mixture ratios on the SERN chemical non-equilibrium *** calculation results show that the strutbased combustor enables convenient modeling of various SERN entry conditions,which is similar with many preceding investigations,by changing the injector strut position and controlling the mass flow rate of each *** non-equilibrium effects function in the whole SERN,especially in the initial flow expansion region,leads to obviously higher SERN performance of the non-equilibrium flow than that of the frozen ***,the distributed fuel injection pattern plays a significant role in enhancing the combustion efficiency in combustor,but weakening the chemical non-equilibrium effects funciton in ***,while the equivalent mixture ratio increases,the SERN thrust coefficient and lift coefficient rise gradually,and the increment of non-equilibrium flow in relation to frozen flow becomes higher as *** be specific,the equivalent mixture ratio is 0.6,the maximum increment of thrust coefficient and lift coefficient are 11.6% and 25% respectively.

关键词： scramjet engine single expansion ramp nozzle chemical non-equilibrium fuel injection position equivalent mixture ratio

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A Stability Criterion for Time-Delay Tension Leg Platform Systems Subjected to External Force

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China Ocean Engineering 2009年第1期23卷 49-57页

作者： Chen-yuan CHEN Chien-wen SHEN cheng-Wu CHEN Kevin Fong-Rey LIU Ming-jen cheng Department of Management Information System Yung- Ta Institute of Technology and Commerce Ping-Tung County 90941 China Department of logistics Management National Kaohsiung First University of Science and Technalgy Kaohsiung City 811 China Department of Logistics Management Shu- Te University Kaohsiung 82445 China Graduate Institute of Management National Kaohsiung First University of Science and Technolgy Kaohsiung City 811 China Department of Safety Health and Environmental Engineering Ming Chi University of Technology Taipei 24301 China

Stability analysis plays a central role in nonlinear system theory and engineering application. Over the past few years, the stability analysis of fuzzy systems has been proposed and there are many successful applications in practical engineering. Therefore, in this paper firstly proposed is the stability analysis on oceanic structure by fuzzy models. In the present study, Takagi-Sugeno （T-S） fuzzy model is proposed for a time delay tension leg platform （TLP） system subjected to an external wave force. In terms of stability analysis, linear matrix inequality （LMI） conditions are derived via Lyapunov theory to guarantee the stability of the TLP system.

关键词： linear matrix inequality tension leg platform fuzzy model

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Thermal-structural response and low-cycle fatigue damage of channel wall nozzle

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Chinese Journal of Aeronautics 2013年第6期26卷 1449-1458页

作者： cheng cheng Wang Yibai Liu yu Liu Dawei Lu Xingyu School of Astronautics Beihang University

To investigate the thermo-mechanical response of channel wall nozzle under cyclic working loads,the fnite volume fluid-thermal coupling calculation method and the fnite element thermal-structural coupling analysis technique are *** combination with the material lowcycle fatigue behavior,the modifed continuous damage model on the basics of local strain approach is adopted to analyze the fatigue damage distribution and accumulation with increasing nozzle work *** results have shown that the variation of the non-uniform temperature distribution of channel wall nozzle during cyclic work plays a signifcant role in the thermal-structural response by altering the material properties;the thermal-mechanical loads interaction results in serious deformation mainly in the front region of slotted *** particular,the maximal cyclic strains appear in the intersecting regions of liner gas side wall and symmetric planes of channel and rib,where the fatigue failure takes place initially;with the increase in nozzle work cycles,the residual plastic strain accumulates linearly,and the strain amplitude and increment in each work cycle are separately equal,but the fatigue damage grows up *** a result,a simplifed nonlinear damage accumulation approach has been suggested to estimate the fatigue service life of channel wall *** predicted node life is obviously conservative to the Miner＇s *** addition,several workable methods have also been proposed to improve the channel wall nozzle durability.

关键词： Channel wall nozzle Damage Life Low-cycle fatigue Reusable engine Thermal-structural response

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From blocker to booster:Harnessing garnet surface chemistry for advanced solid-state electrolytes

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Nano Research 2025年第1期18卷 323-331页

作者： Jun cheng Xuan Zhou Hongqiang Zhang Zhen Zeng yuanyuan Li yulong Zhu Yingsheng Liao Lijie Ci Deping Li State Key Laboratory of Precision Welding and Joining of Materials and Structures School of Materials Science and EngineeringHarbin Institute of Technology(Shenzhen)Shenzhen 518055China

Garnet electrolytes with high ionic conductivity and electrochemical stability are widely used as fillers to fabricate composite solid electrolytes(CPEs)within polymer ***,the performance of CPEs is significantly influenced by the surface characteristics of the garnet ***,the impact of garnet surface characteristics on CPEs was systematically investigated and a conversion from a typically unstable and Lewis basic surface to a more stable Lewis acidic surface was realized,which is shown to be more conductive to the improved performance of *** simultaneously removing the Li_(2)CO_(3)layer and applying a Li-Al-O coating,the influence of surface characteristics on CPEs was *** Lewis acid Li-Al-O surface coating not only promotes lithium salt dissociation,improving the ionic conductivity and ionic transfer number,but also prevents the reformation of the passive Lewis basic Li_(2)CO_(3)*** to garnet with a Lewis basic Li_(2)CO_(3)surface,the garnet modified with a Lewis acid Li-Al-O coating enhances CPEs,which exhibit an improved critical current density of 1.0 mA·cm^(-2)and highly stable lithium symmetric cell cycling for 400 h at 0.2 mA·cm^(-2).This research highlights the importance of surface chemistry in the design of high-performance solid-state batteries and presents a strategic modification approach for garnetbased CPEs.

关键词： garnet electrolyte composite solid electrolyte surface chemistry all-solid-state batteries

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Enhancing output performance of triboelectric nanogenerator by increasing charge storage capacity of electrodes

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Nano Research 2025年第1期18卷 395-403页

作者： Congcong Hao Zekun Wang Mingzhe Cai Shuaining cheng Zhongxin Wang Cong Zhai Juan Cui Yongqiu Zheng Chenyang Xue Key Laboratory of Instrumentation Science and Dynamic Measurement Ministry of Education North University of ChinaTaiyuan 030051China

ABSTRACT:The practical application of rotating triboelectric nanogenerators is often limited by the wear of high-friction surface materials and low surface charge *** addition to the charge pump replenishment strategy,suppressing charge decay is also crucial for increasing surface charge ***,we present a high performance rotary triboelectric nanogenerator(HPR-TENG)based on a coplanar charge pumping strategy and polyvinyl chloride(PVC)*** has been demonstrated that applying PVC film to the surface of the storage electrode of the main TENG(M-TENG)significantly enhances the M-TENG’s output ***,the HPR-TENG with three layers of PVC film pasted achieved the best output performance,with a peak-topeak output voltage of 2828 V,a peak-to-peak output current of 327μA and a charge transfer of 0.81μC at 500 *** addition,the output improvement effects of different materials are *** TENG with 3 layers of PVC film pasted on it has a maximum output power of 748 mW at a load resistance of 4×10^(6)Ω.HPR-TENG’s output performance remains consistent after 100,000 cycles,which shows excellent *** excellent electrical performance of the HPR-TENG can be used as the energy supply for the tip high-voltage breakdown sensor system,which can achieve 14 breakdowns in 10 *** to its extraordinary electrical performance,HPRTENG can not only serve as an energy supply for cutting-edge high-voltage breakdown sensor systems,but also has the potential to serve as an energy supply for high-pressure sterilization,high-pressure vacuum and water electrolysis.

关键词： triboelectric nanogenerator coplanar charge pump enhancing charge density suppressing charge decay polyvinyl chloride(PVC)film

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Experimental investigation on the characteristics of molten lead–bismuth non-eutectic alloy fragmentation in water

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Nuclear Science and Techniques 2022年第9期33卷 59-79页

作者： Shao-Jie Tan yu-Bao Zhong Hui cheng Song-Bai cheng Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China

To study the interaction between molten noneutectic alloys and subcooled water during severe nuclear accidents,an experimental investigation was carried out by injecting molten lead–bismuth non-eutectic alloy(LBNE,70%Pb-30%Bi)into the water in a free-fall style using the visualized thermo-hydraulic characteristics in melt coolant interaction(VTMCI)*** effects of various experimental parameters,including water temperature,melt temperature,melt penetration velocity,and water depth,on the molten LBNE jet fragmentation characteristics were *** research shows that compared with lead–bismuth eutectic,larger fragments,less spherical fragments,and more porous debris beds are generated for *** water or melt temperatures facilitate molten LBNE fragmentation,resulting in higher debris bed sphericity and lower debris bed porosity.A higher melt temperature leads to smaller fragment sizes,except that a cake-like debris bed is formed for very high alloy superheat and very low water *** approximate spherical particles were generated in the film boiling zone than in the thermal interaction *** size decreases with an increase in the melt penetration velocity,but the debris bed porosity and sphericity variation was not *** effect of water depth on molten LBNE fragmentation behavior was not obvious under the current experimental *** with other fragmentation theories,the Weber number theory better predicted the fragment volume mean *** addition,a melt-jet behavior mode diagram that describes the competition between the hydrodynamic and thermal interactions and diagrams of debris bed porosity and sphericity that show the influence of thermal factors were analyzed in this study.

关键词： Fuel-coolant interaction Coolant-coolant interaction Debris bed Lead-bismuth non-eutectic alloy-water interaction Fragmentation behavior

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Endpoint Estimates for Commutators of Multilinear Fractional Integral Operators

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Acta Mathematica Sinica,English Series 2010年第3期26卷 433-444页

作者： Xiao yu Jie cheng CHEN Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China

In this paper, the weak type LlogL estimate for the multilinear fractional commutator is obtained by introducing a new kind of maximal operator of the multilinear fractional order associated with the mean Luxumburg no... 详细信息

关键词： multilinear commutator Young function Luxemburg norm fractional integral

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Using the Haddon matrix to explore medical response strategies for terrorist subway bombings

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Military Medical Research 2019年第4期6卷 320-327页

作者： Tie-cheng Yan Min yu Institute of Health Service and Transfusion Medicine Academy of Military Medical SciencesNo.27 Taiping RoadBeijing 100850China

Background:Since the 1970 s,terrorist bombings in subways have been frequently occurring *** cope with this threat and to provide medical response countermeasures,we analyzed the characteristics of subway bombing terrorist attacks and used the Haddon matrix to explore medical response ***:First,we analyzed 111 subway bombings from 1970 to 2017 recorded in the Global Terrorism Database to provide a reference for the strategy ***,we convened an expert panel to use the Haddon matrix to explore the medical response strategies to subway ***:In recent decades,at least one bombing attack occurs every 3 *** by the Haddon matrix,the influencing factors of medical responses to conventional subway bombings include the adequacy of first-aid kits and the medical evacuation equipment,the traffic conditions affecting the evacuation,the continuity and stability of communication,as well as the factors exclusively attributed to dirty bomb attacks in subways,such as ionizing radiation protection capabilities,the structure of the radiation sickness treatment network based on the subway lines,and the disposal of radioactive *** factors form the basis of the strategy ***:Since subway bombings are long-term threats,it is necessary to have proper medical response *** on the Haddon matrix,we explored the medical response strategies for terrorist subway bombings,especially dirty bomb *** matrix can help policymakers systematically find the most important factors,which makes the preparations of the response more efficient.

关键词： Haddon matrix Subway Terrorism Bomb attack Medical response

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The synthesis and applications of α-zirconium phosphate

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Chinese Chemical Letters 2020年第2期31卷 307-310页

作者： yu cheng Gaik Khuan Chuah Department of Chemistry National University of SingaporeSingapore 117543Singapore

The synthesis of α-ZrP with a range of crystallinity is of high importance due to the different requirements in various *** crystalline α-ZrP is typically obtained by refluxing amorphous ZrP in concentrated H3PO4 *** α-ZrP are obtained by direct precipitation in the presence of either HF or oxalic acid which are used as complexing agents for *** larger crystals are useful as ion-exchangers in column-type applications as the back pressure can be significantly reduced.A novel minimalistic synthesis that is green,simple and fast is highlighted in this *** nano-sized and micro-sized α-ZrP can be prepared via this protocol to meet many potential *** of α-ZrP in ion-exchange,catalysis,lubricants,intercalation hosts,polymer fillers and fire retardants are discussed.

关键词： Zirconium phosphate Green synthesis Ion exchanger Tribology Catalysis

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Human Detection for Video Surveillance in Hospital

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Journal of Electronic Science and Technology 2017年第2期15卷 147-152页

作者： cheng-Hung Chuang Zhen-You Lian Po-Ren Teng Miao-jen Lin Department of Computer Science and Information Engineering Asia UniversityTaichung 41354 the Psychiatry Department Chang Bing Show Chwan Memofial Hospital Changhua 50544

This paper presents a human detection system in a vision-based hospital surveillance environment. The system is composed of three subsystems, i.e. background segmentation subsystem （BSS）, human feature extraction subsystem （HFES）, and human recognition subsystem （HRS）. The codebook background model is applied in the BSS, the histogram of oriented gradients （HOG） features are used in the HFES, and the support vector machine （SVM） classification is employed in the HRS. By means of the integration of these subsystems, the human detection in a vision-based hospital surveillance environment is performed. Experimental results show that the proposed system can effectively detect most of the people in hospital surveillance video sequences.

关键词： Index Terms--Background segmentation codebook histogram of oriented gradients (HOG) human classification support vector machine (SVM) video surveillance.

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