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Numerical investigation of the propagation characteristics of H 2 -f 2 -Air fueled rotating detonation waves

Defence Technology 2025年

作者： Xinzhe Jiang Baoxing Li Yanjing Yang Jianming Yang Xiaohong Zhang Xi’an Modern Chemistry Research Institute Xi’an 710065 China

The incorporation of fluorine (f 2 ) into hydrogen-air (H 2 /Air) mixtures presents a novel approach to enhancing the performance of rotating detonation engines (RDEs). This study systematically investigates the effects of f 2 concentration and inlet mass flow rate on rotating detonation wave (RDW) propagation using two-dimensional numerical simulations, providing the first comprehensive analysis of f 2 as an oxidizing additive in regulating detonation performance, propagation stability, and heat release dynamics in RDEs. The results indicate that when f 2 concentration is below 1%, the flow field primarily exhibits a stable single-wave propagation mode. As f 2 concentration increases, RDW performance initially improves but then deteriorates, reaching its optimal state at 0.8% f 2 . When f 2 concentration exceeds 1%, the coupled effects of f 2 concentration and inlet mass flow rate induce a transition from single-wave to multi-wave propagation modes. While a higher inlet mass flow rate promotes increased wave numbers, it also intensifies wave-wave interactions. With further increases in f 2 concentration, the enhanced heat release leads to intensified local deflagration, frequent hotspot formation, and wave collisions, ultimately degrading RDW performance and destabilizing the multi-wave flow field. Moreover, excessive Hf formation is identified as a critical driver of enhanced deflagration, hotspot generation, and the disruption of multi-wave stability. These findings provide a theoretical foundation for integrating f 2 additives into H 2 /Air-based RDE systems.

关键词： Rotating detonation engine f 2 additives H 2 /f 2 detonation combustion Propagation characteristics Multi-wave flow field stability

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Location of fluorine atoms and mechanism of improving superconducting properties with f-doped in YBaCuO series

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中国有色金属学会会刊：英文版 2000年第2期10卷 176-182页

作者：邓辉球高孝恢王小刚赵立华 Hunan Univ Dept Appl Phys Changsha 410082 Peoples R China Cent S Univ Technol Dept Chem Changsha 410083 Peoples R China Hunan Normal Univ Dept Phys Changsha 410081 Peoples R China

A series of YBa 2Cu 3O 6.5-0.5x+δ f x (x=0, 0.3, 0.6, 1.0, 1.5, 2.0) samples were synthesized using state reaction method. The superconducting properties and microstructures of the samples were studied with AC susceptibility, DC resistivity, fluorine and oxygen content measurements, XRD, IR and XPS techniques. The results show that f doping increases the T C and decreases the transition width, and fluorine atoms have entered into the superconducting phase and substituted for the oxygen atoms at O(4) sites. The mechanism of improving superconducting properties is that fluorine doping adjusts the hole carrier concentration in the Cu O planes.

关键词： superconductor YBaCuO f doped

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A novel flame retardant strategy for molten magnesium alloys: The effect of the new protective gas C 3 H 2 f 6 on EV33 alloy

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Journal of Magnesium and Alloys 2025年

作者： Longbiao feng Lunyong Zhang Hongxian Shen Chaojun Zhang Zhi Song Jiaming Cao fuyang Cao Zhiliang Ning Yongjiang Huang Jianfei Sun National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin 150001 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

Resolving the ignition issue of magnesium alloys is essential for broadening their application scope. This research investigates the EV33 magnesium alloy, delving into an innovative flame-retardant strategy, with a specific focus on the impact of the novel protective gas C 3 H 2 f 6 on the flame-retardant properties of the alloy. This paper unveils the morphological characteristics of the EV33 magnesium alloy surface in the absence of protective gas, while employing thermodynamic principles to establish the preferential reaction stages of the alloy, computing the residual stress of Mgf 2 , and assessing the flame-retardant and antioxidative properties of C 3 H 2 f 6 . The study finds that under conditions without protective gas, the oxide film on the EV33 alloy surface is prone to cracking, which accelerates the ignition process of the alloy. Conversely, in an environment enriched with C 3 H 2 f 6 , the formation of a dense oxide film on the alloy surface significantly enhances its thermal stability and flame-retardant properties. This mechanism encompasses the formation of a secondary oxide film, where C 3 H 2 f 6 accelerates the rapid development of this film, effectively repairing damage to the primary oxide film and inhibiting further diffusion of the oxidation reaction. furthermore, this study elucidates the origin of oxide film rupture, showing that under conditions without protective gas, the precipitated phases and grain boundaries on the surface of the alloy induce the rupture of the oxide film, attributed to stress concentration phenomena occurring around the grain boundaries.

关键词： Ignition Oxidation EV33 alloy C 3 h 2 f 6 gas Oxide film rupture Residual stress

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Reliability evaluation of consecutive k-out-of-m: f balanced systems with a symmetry line

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PROCEEDINGS Of THE INSTITUTION Of MECHANICAL ENGINEERS PART O-JOURNAL Of RISK AND RELIABILITY 2022年第5期236卷 816-827页

作者： fang, Chen Cui, Lirong Zhejiang Ocean Univ Sch Econ & Management No 1Haida South RdLincheng New Area Zhoushan 316022 Zhejiang Peoples R China Beijing Inst Technol Sch Management Econ Beijing Peoples R China

Based on some real backgrounds, a new balanced system structure, a consecutive k-out-of-m: f system with a symmetry line, is proposed in this paper. Considering different state numbers of a subsector, the new balanced system is analyzed under two situations respectively: the subsector with binary-state and the subsector with multi-state, while the multi-state balanced systems have not been studied in the previous research. Besides, two models are developed in terms of assumptions for the two situations, respectively. for this system, several methods, such as the finite Markov chain imbedding approach, the order statistics technique and the phase-type distributions, are used on the models. In addition to system reliability formulas, the means and variances of the system lifetimes under two models for different situations are given. finally, numerical examples are presented to illustrate the results obtained in this paper.

关键词： Balanced system phase-type distributions finite Markov chain imbedding approach consecutive k-out-of-m f

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Precision frequency Measurement of ^(87)Rb 5S_(1/2)(f=2)→5D_(5/2)(f″=4)Two-Photon Transition through a fiber-Based Optical frequency Comb

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Chinese Physics Letters 2016年第5期33卷 30-34页

作者：夏巍戴少阳张胤李坤乾于齐陈徐宗 Institute of Quantum Electronics School of Electronics Engineering and Computer SciencesPeking University Jiangsu Key Laboratory on Opto-electronic Technology School of Physics and TechnologyNanjing Normal University

The absolute frequency of 87Rb 5S1/2 （f=2）→5D5/2 （f＂ = 4） two-photon transition at 778nm is measured in an accuracy of 44kHz. A home-made erbium-doped fiber laser frequency comb with frequency stability of 5.0 × 10-13@1 s is employed for the light source. By using a periodically poled lithium niobate, the femtosecond pulse operating in 1556 nm is frequency-doubled to 778 nm to obtain the direct two-photon transition spectroscopy of thermal rubidium vapor. Through sweeping the carrier envelope offset frequency （fceo）, the 5S1/2 （f=2）→5D5/2 （f＂ = 4） two-photon transition line is clearly resolved and its absolute frequency is determined via the peak-finding of the fitting curve. After the frequency correction, the measured result agrees well with the previous experiment on this transition. The entire potential candidate of optical frequency standard for system configuration is compact and robust, providing a telecommunication applications.

关键词： Precision frequency Measurement of in is f=2 on as been Rb 5S f Two-Photon Transition through a fiber-Based Optical frequency Comb

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Phase and structure of polycrystal Sr_(0.69) La_(0.31)f_(2.31)+SrS solid electrolyte material

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中国有色金属学会会刊：英文版 1999年第3期9卷 541-545页

作者： Tian Yanwen(田彦文), Ma Ping(马平), Zhang Xin(张新), Zhai Yuchun(翟玉春) School of Materials and Metallurgy, Northeastern University, Shenyang 110006, P. R. China Northeastern Univ Sch Met & Mat Shenyang 110006 Peoples R China

The phase and the structure of polycrystal material, which was prepared by calcining the co precipitated fluoride powder of Sr and La with a ratio of 0.69∶0.31 mixed with SrS powder, were investigated by X ray diffraction and electron probe scanning. In the materials, three phases were found, they are Sr 0.69 La 0.31 f 2.31 solid solution phase with a pure Srf 2 cubic structure whose lattice constant is 5.843 ?, SrS single phase with a NaCl cubic structure, and an unknown phase that is produced by the interaction of SrS and co precipitated powder. It was also found that SrS has no influence on the structure of Sr 0.69 La 0.31 f 2.31 solid solution.

关键词： X ray diffraction electron probe polycrystal Sr 0.69 La 0.31 f 2.31 +SrS material phase structure

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Effect of milling material on characteristics and reactivity of mechanically treated fly ash to produce PCDD/f

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JOURNAL Of THERMAL ANALYSIS AND CALORIMETRY 2021年第3期143卷 2707-2716页

作者： Mubeen, Ishrat Shengyong, Lu Jianhua, Yan Khan, Muhammad Sajid Yan, Mi Ali, Hafiz Muhammad Zhejiang Univ Technol Inst Energy & Power Engn Hangzhou 310014 Peoples R China Zhejiang Univ Inst Thermal Power Engn State Key Lab Clean Energy Utilizat Hangzhou 310027 Peoples R China KFUPM Mech Engn Dept Dhahran 31261 Saudi Arabia

Municipal solid waste incineration produces huge amount of fly ash containing chlorides, leachable heavy metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/f or dioxins). High-intensity ball milling was applied to model fly ash (MfA) samples at 300 rpm (1 and 8 h) which were composed of silica, sodium chloride, activated carbon and doped with metal (0.2 wt.% Cu, Cr, fe, Zn and Ca) chlorides. Effect of ball mill made of stainless steel and zirconia material was evaluated on characteristics and reactivity of MfA to produce PCDD/f. The characterization tests revealed that after milling treatment, MfAs with different metal catalysts showed similar changes in mass, distribution of metal catalysts, surface morphology, crystalline phases and graphitic structure of activated carbon. These changes were more pronounced in MfA milled with stainless steel material compared to zirconia. However, effect of milling material on the reactivity of MfA to form PCDD/f was almost similar in Cu-doped MfA, despite of homogenous dispersion of catalytic metal. The reactivity of all selected MfAs was greatly reduced after prolonged milling treatment and can be disposed of safely into landfills.

关键词： Municipal solid waste incineration fly ash PCDD f Mechanical treatment Stainless steel Zirconia

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Statistical analysis and model of spread f occurrence in China

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Science China(Technological Sciences) 2010年第6期53卷 1725-1731页

作者： XU Tong1,WU ZhenSen2,HU YanLi1,WU Jian1,SUO YuCheng1 & fENG Jian1 1 National Key Laboratory of Electromagnetic Environment,China Research Institute of Radiowave Propagation,Qingdao 266107,China 2 School of Science,Xidian University,Xi’an 710071,China 1. National Key Laboratory of Electromagnetic Environment China Research Institute of Radiowave Propagation Qingdao 266107 China2. School of Science Xidian University Xi’an 710071 China

The spread f data obtained over Lanzhou (36.1°N,103.9°E),Chongqing (29.5°N,106.4°E) and Haikou (20.0°N,110.3°E) of China during the period from 1978 to 1997 are used to analyze the occurrence *** statistical results show that the post midnight spread f occurrence is maximum during the summer solstice months of the lower solar activity period,while post sunset spread f is dominant in equinoxes of higher solar activity period over Haikou *** Chongqing and Lanzhou stations,spread f mostly occurs at post midnight and relates negatively with solar *** regression method and fourier expansion,the preliminary single-station model of spread f occurrence is established and the accuracy of the model is evaluated.

关键词： spread f solar cycle variation seasonal variation empirical model

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ON ALGEBRAIC PROPERTIES Of f-SPACES

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fUZZY SETS AND SYSTEMS 1990年第2期36卷 293-303页

作者： TOTH, H A-1140 Wien Riedstrasse 17A Austria

Recently a new perspective of fuzzy set theory has been presented under the name ‘ f -set theory’. Here we investigate the most fundamental algebraic properties of f -subsetness, f -intersection, f -union, and f -complementation. The latter one is shown not only to have intuitive and operational roots, but also to arise if one starts the generalization process from algebraic instead of arithmetical representation for classical complementation.

关键词： Operational viewpoint set-theoretical operations f -complementation

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In-situ measurements of magmatic volatile elements, f, S, and Cl, by electron microprobe, secondary ion mass spectrometry, and heavy ion elastic recoil detection analysis

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AMERICAN MINERALOGIST 2020年第5期105卷 616-626页

作者： Rose-Koga, Estelle f. Koga, Kenneth T. Devidal, Jean-Luc Shimizu, Nobumichi Le Voyer, Marion Dalou, Celia Dobeli, Max Univ Clermont Auvergne Lab Magmas & Volcans OPGC CNRS UMR6524IRD F-63000 Clermont Ferrand France Woods Hole Oceanog Inst Dept Geol & Geophys Woods Hole MA 02543 USA Natl Museum Nat Hist Smithsonian Inst POB 37012MRC 119 Washington DC 20013 USA Univ Lorraine Ctr Rech Petrog & Geochim CNRS UMR7358 BP20 Vandoeuvre Les Nancy 54501 France Swiss Fed Inst Technol Lab Ion Beam Phys CH-8093 Zurich Switzerland

Electron probe and ion probe are the two most used instruments for in situ analysis of halogens in geological materials. The comparison of these two methods on widely distributed glass standards (example: MPI-DING glasses, Jochum et al., G-cubed, 2006) provides a basis for establishing laboratory method, independent geochemical data sets for these elements. We report analyses of f, S, and Cl concentrations in three geological glass samples (EPMA) and 10 referenced standards (EPMA and SIMS). furthermore, f and Cl absolute abundances have been determined independently for three of the standards (KL2-G, ATHO-G, and KE12), via heavy ion elastic recoil detection analysis (HIERDA), to certify the accuracy of the cross-calibration EPMA-SIMS. The detection limits for EPMA are a 150 mu g.g(-1) for f, 20 mu g.g(-1) for S and Cl, and for SIMS < 48 mu g.g(-1) for f, < 3 mu g.g(-1) for S, and <19 mu g.g(-1) for Cl. On SiO2-rich glass-standards, f and Cl measurements by HIERDA highlight a weak matrix effect during SIMS analysis of f and Cl. With the HIERDA independently measured value, we therefore propose an alternative calibration function to empirically correct this matrix effect on the SIMS measurements of f, S, and Cl.

关键词： f Cl SIMS EPMA ERDA melt inclusion Halogens in Planetary Systems

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