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Catalytic performance and reaction mechanisms of NO removal with NH_(3) at low and medium temperatures on Mn-W-Sb modified siderite catalysts

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Journal of Environmental Sciences 2022年第5期34卷 126-139页

作者： Guihuan Yao Yuliang Wei Keting Gui xiang ling School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816China School of Energy and Environment Southeast UniversityNanjing 210096China

Iron-based catalysts have been explored for selective catalytic reduction(SCR)of NO due to environmentally benign characters and good SCR ***-W-Sb modified siderite catalysts were prepared by impregnation method based on siderite ore,and SCR perfor-mance of the catalysts was *** catalysts were analyzed by X-ray diffrac-tion,H_(2)-temperature-programmed reduction,Brunauer-Emmett-Teller,Thermogravimetry-derivative thermogravimetry and in-situ diffused reflectance infrared Fourier transform spectroscopy(DRIFTS).The modified siderite catalysts calcined at 450℃ mainly consist of Fe_(2)O_(3),and added Mn,W and Sb species are amorphous.3Mn-5W-1.5Sb-siderite catalyst has a wide temperature window of 180-360℃ and good N_(2) selectivity at low ***-situ DRIFTS results show NH_(4)^(+),coordinated NH_(3),NH_(2),NO_(3)^(-)species(bidentate),NO_(2)-species(nitro,nitro-nitrito,monodentate),and adsorbed NO_(2) can be discovered on the sur-face of Mn-W-Sb modified siderite catalysts,and doping of Mn will enhance adsorbed NO_(2) formation by synergistic catalysis with Fe^(3+).In addition,the addition of Sb can inhibit sulfates formation on the surface of the catalyst in the presence of SO_(2) and H_(2)***-dependent in-situ DRIFTS studies also indicate that both of Lewis and Br?nsted acid sites play a role in SCR of NO by ammonia at low *** mechanism of NO removal on the 3Mn-5W-1.5Sb-siderite catalyst can be discovered as a combination of Eley-Rideal and Langmuir-Hinshelwood mechanisms with three reaction *** mechanism of NO,oxidized by synergistic catalysis of Fe^(3+)and Mn^(4+/3+)to form NO_(2) among three pathways,reveals the reason of high NO_(x) conversion of the catalyst at medium and low temperatures.

关键词： Iron-based catalysts Mn-W-Sb In-situ diffused reflectance infrared Fourier transform spectroscopy Reaction mechanism Siderite Low and medium temperature

Frequency Loss and Recovery in Rolling Bearing Fault Detection

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Chinese Journal of Mechanical Engineering 2019年第2期32卷 145-156页

作者： Aijun Hu ling xiang Sha Xu Jianfeng Lin Department of Mechanical Engineering North China Electric Power University

Rolling element bearings are key components of mechanical equipment. The bearing fault characteristics are a ected by the interaction in the vibration signals. The low harmonics of the bearing characteristic frequencies cannot be usually observed in the Fourier spectrum. The frequency loss in the bearing vibration signal is presented through two independent experiments in this paper. The existence of frequency loss phenomenon in the low frequencies, side band frequencies and resonant frequencies and revealed. It is demonstrated that the lost frequencies are actually suppressed by the internal action in the bearing fault signal rather than the external interference. The amplitude and distribution of the spectrum are changed due to the interaction of the bearing fault signal. The interaction mechanism of bearing fault signal is revealed through theoretical and practical analysis. Based on mathematical morphology, a new method is provided to recover the lost frequencies. The multi-resonant response signal of the defective bearing are decomposed into low frequency and high frequency response, and the lost frequencies are recovered by the combination morphological filter(CMF). The e ectiveness of the proposed method is validated on simulated and experimental data.

关键词： Rolling element bearing Signal processing Frequency loss Fault detection Morphological filter

Risk Assessment of Highways Affected by Debris Flows in Wenchuan Earthquake Area

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Journal of Mountain Science 2013年第2期10卷 173-189页

作者： CUI Peng xiang ling-zhi ZOU Qiang Institute of Mountain Hazards and Environment/Key Laboratory of Mountain Hazards and Earth Surface Process Chinese Academy of Sciences Chongqing Jiaotong University Graduate University Chinese Academy of Sciences College of Environmental and Resource Southwest University of Science and TechnologyChina

Since the Wenchuan earthquake in China on May 12th, 2008, highways in earthquake-affected areas have been frequently interrupted by debris flows. We analyzed the hazard effect modes and damage processes along highways and developed three key indexes, scale of debris flows, deposits on highways and river blockage, to describe quantitatively the highway disasters. By combining the empirical methods and the actual terrain conditions, we proposed new methods to determine the value of hazard indexes. In addition, we used the economic value and resistance of highway as vulnerability assessment indexes, then determined the specific subindexes for the subgrade, bridges and culverts, and developed a way for the quantified vulnerability zoning. Moreover, we proposed the assessment and mapping methods for highway risk. The risk is described into 5 grades： extremely low risk, low risk, middle risk, high risk and extremely high risk. We applied these methods in a case study carried out on provincial highway S3o3 from Yingxiu Town to Wolong Town, in Wenchuan County. Analysis of debris flow risk for the whole highway, showed that the total length of highway in extremely low risk area was 28.26 km, 4.83 km in low risk area, 8.0 km in middle risk area, 3.65 km in high risk area, and 3.06 km in extremely high risk area. The assessment results are consistent with the field survey data which reflected the disaster situation. This risk method can be used objectively to evaluate the debris-flow risk along highways, and is useful for highway reconstruction in mountainous areas suffering from active debris flows.

关键词： Debris flow Highway disaster Hazardanalysis Vulnerability analysis Risk analysis Wenchuan earthquake

Deformation Behavior and Formability of Gradient Nano-grained AISI 304 Stainless Steel Processed by Ultrasonic Impact Treatment

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Journal of Wuhan University of Technology(Materials Science) 2017年第5期32卷 1147-1155页

作者：杨新俊 ling xiang WANG Dongxiang 王伟 Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment & Technology School of Mechanical Engineering Jiangnan University Wuxi 214122 China Jiangsu Key Laboratory of Process Enhancement and New Energy Equipment Technology School of Mechanical and Power Engineering Nanjing Tech University Nanjing 211816 China School of Automotive Engineering Wuhan University of Technology Wuhan 430070 China Hubei Province Key Laboratory of Modern Automotive Technology Wuhan 430070 China Hubei Province Automotive Parts Synergy Innovation Center Wuhan 430070 China

The deformation behavior and formability of gradient nano-grained（GNG） AISI 304 stainless steel in uniaxial and biaxial states were investigated by means of tensile test and small punch test（SPT）. The GNG top layer was fabricated on coarse grains（CG） AISI 304 by ultrasonic impact treatment. The results showed that the CG substrate could effectively suppress the strain localization of NC in GNG layer, and an approximate linear relationship existed between the thickness of substrate（h） and uniform true strain before necking（ε_（unif））. Grain growth of NC was observed at the stress state with high Stress triaxiality T, which led to better ductility of GNG/CG 304 in SPT, as well as similar true strain after the onset of necking（ε_（neck）） compared with coarse 304 in tensile test. Ei-values of GNG/CG 304 with different structures were nearly the same at different punch speeds, and good formability of GNG/CG 304 was demonstrated. However, punch speed and microstructure needed to be optimized to avoid much lost of membrane strain region in biaxial stress state.

关键词： gradient nano-grained structure deformation behavior formability ultrasonic impact treatment AISI 304 stainless steel

Vultures as a model for testing molecular adaptations of dietary specialization in birds

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Avian Research 2023年第3期14卷 425-434页

作者： Yanhong Chen ling xiang Pan Chen Huabin Zhao Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources College of Life SciencesAnhui Normal UniversityWuhu241000China Key Laboratory of Biodiversity and Environment on the Qinghai-Tibetan Plateau Ministry of EducationCollege of Life SciencesWuhan UniversityWuhan430072China Key Laboratory of Biodiversity and Environment on the Qinghai-Tibetan Plateau Ministry of EducationSchool of Ecology and EnvironmentTibet UniversityLhasa850000China

Vultures are the only obligate scavengers among extant *** provide valuable ecological services in ecosystems through removing carcasses,thus preventing the growth of other scavenger populations and the spread of ***,their specific diets expose them to various deadly pathogens,which makes them potential candidates for studying molecular adaptations required to survive this extremely specialized scavenging *** this review,we summarize the morphological characteristics and behavioral habits,origin and phylogeny,and molecular adaptations to scavenging in both Old and New World *** two groups of vultures share a similar appearance,indicative of convergent *** have experienced different degrees of specialization in their sensory organs;Old World vultures depend on sight,while New World ones depend on both smell and *** fossil records and molecular data suggest that vultures evolved independently,with distinct phylogenetic *** also explored their adaptation to scavenging in facial and intestinal microbiomes,gastric acid secretion and *** with the facial microbiome,the intestinal microbiome had a lower diversity,dominated by Fusobacteria and *** phages and single invertebrate species Adineta vaga,which feeds on dead bacteria and protozoa,present in the gut suggest a possible alternative defense *** genes involved in gastric acidic secretion(including ATP4B,SLC26A7 and SST)and immunity(including BCL6,STING,and TLRs) undergoing positive selection likely have essential roles in eliminating invasive pathogens and initiating an innate immune *** together,this review presents the current research status of vultures and highlights the use of vultures as a model for exploring molecular adaptations of dietary specialization in *** also provides a theoretical basis for the study of the genetic mechanisms of vultures to scavenging,and contributes to the

关键词： Vultures Scavenging Molecular adaptation Microbiomes Gastric acidic secretion Immunity

Experimental and numerical studies of Ca(OH)_(2)/CaO dehydration process in a fixed-bed reactor for thermochemical energy storage

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Chinese Journal of Chemical Engineering 2023年第10期62卷 11-20页

作者： Zhihao Zhang Danyang Song Hengxing Bao xiang ling Xiaogang Jin School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816China

The Ca(OH)_(2)/CaO thermochemical energy storage(TCES)system based on calcium looping has received extensive attention owing to its high energy storage density,prolonged energy storage time,and environmental *** heat storage process of the Ca(OH)_(2)/CaO TCES system in a mixed heating reactor was evaluated in this study,by employing a combination of direct and indirect heating *** dehydration process was studied experimentally,and a numerical model was established and verified based on the experimental *** dehydration behavior of 500 g of Ca(OH)_(2) powder was investigated in a fixed-bed reactor with mixed *** experimental and simulation results indicated that mixed heating causes combined centripetal and horizontal *** input is the main limiting factor in the heat storage process,because the radial advance of the reaction is hindered by the low thermal conductivity of the solid reactant *** transmission partitions were added to enhance the performance of the *** performance of the modified reactor was compared with that of a conventional *** radial heat transmission partitions in the modified reactor effectively enhance the energy storage rate and reduce the reaction time by 59.5%compared with the reactor without partitions.

关键词： Thermochemical energy storage Reactor Ca(OH)_(2)/CaO Dehydration Experiment research Numerical simulation

Surface-improvement mechanism of hybrid electrochemical discharge process using variable-amplitude pulses

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Chinese Journal of Aeronautics 2020年第10期33卷 2782-2793页

作者： Yan ZHANG Zhengyang XU Yu WANG Qin NI xiang ling School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211800China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics&AstronauticsNanjing 210016China AECC Sichuan Gas Turbine Research Establishment Chengdu 610500China

Superalloys are commonly used in aircraft manufacturing;however,the requirements for high surface quality and machining accuracy make them difficult to *** this study,a hybrid electrochemical discharge process using variable-amplitude pulses is proposed to achieve this *** this method,electrochemical machining(ECM)and electrical discharge machining(EDM)are unified into a single process using a sequence of variable-amplitude pulses such that the machining process realizes both good surface finish and high machining ***,the machining mechanism of the hybrid electrochemical discharge process using variable-amplitude pulses is *** mechanism is investigated by observations of machining waveforms and machined *** is found that,with a high-frequency transformation between high-and low-voltage waveforms within a voltage cycle,the machining mechanism is frequently transformed from EDM to pure *** critical discharge voltage is 40 *** pulse voltages greater than 40 V are applied,the machining accuracy is good;however,the surface has defects such as numerous discharge *** machining accuracy is maintained when high-voltage pulses are replaced by low-voltage pulses to enhance electrochemical *** results indicate that the proposed hybrid electrochemical discharge process using variable-amplitude pulses can yield high-quality surfaces with high machining accuracy.

关键词： Electrical discharge machining Electrochemical machining Hybrid machining Superalloy Variable-amplitude pulse

Complex Dynamics in Physical Pendulum Equation with Suspension Axis Vibrations

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Acta Mathematicae Applicatae Sinica 2010年第1期26卷 55-78页

作者： xiang-ling Fu Jin Deng Zhu-jun Jing College of Mathematics and Computer Sciences Hunan Normal University Changsha 410081 China School of Mathematics Hunan University of Science and Technology Xiangtan 411201 China Academy of Mathematics and Systems Sciences Chinese Academy of Sciences Beijing 100190 China Department of Mathematics and Physics Hunan Institute of Engineering Xiangtan 411104 China

The physical pendulum equation with suspension axis vibrations is investigated. By using Melnikov＇s method, we prove the conditions for the existence of chaos under periodic perturbations. By using second-order averaging method and Melinikov＇s method, we give the conditions for the existence of chaos in an averaged system under quasi-periodic perturbations for Ω = nω ＋ εv, n = 1 - 4, where ν is not rational to ω. We are not able to prove the existence of chaos for n = 5 - 15, but show the chaotic behavior for n = 5 by numerical simulation. By numerical simulation we check on our theoretical analysis and further exhibit the complex dynamical behavior, including the bifurcation and reverse bifurcation from period-one to period-two orbits; the onset of chaos, the entire chaotic region without periodic windows, chaotic regions with complex periodic windows or with complex quasi-periodic windows; chaotic behaviors suddenly disappearing, or converting to period-one orbit which means that the system can be stabilized to periodic motion by adjusting bifurcation parameters α, δ, f0 and Ω; and the onset of invariant torus or quasi-periodic behaviors, the entire invariant torus region or quasi-periodic region without periodic window, quasi-periodic behaviors or invariant torus behaviors suddenly disappearing or converting to periodic orbit; and the jumping behaviors which including from period- one orbit to anther period-one orbit, from quasi-periodic set to another quasi-periodic set; and the interleaving occurrence of chaotic behaviors and invariant torus behaviors or quasi-periodic behaviors; and the interior crisis; and the symmetry breaking of period-one orbit; and the different nice chaotic attractors. However, we haven＇t find the cascades of period-doubling bifurcations under the quasi-periodic perturbations and show the differences of dynamical behaviors and technics of research between the periodic perturbations and quasi-periodic perturbations.

关键词： Pendulum equation suspension axis vibrations averaging method Melnikov's method bifurcations chaos

Bifurcations of Resonant Solutions and Chaos in Physical Pendulum Equation with Suspension Axis Vibrations

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Acta Mathematicae Applicatae Sinica 2010年第4期26卷 677-704页

作者： xiang-ling Fu Jin Deng Jian-ping Yang School of Mathematics Hunan University of Science and TechnologyHunan 411201China College of Mathematics and Computer Sciences Hunan Normal UniversityHunan 410081China Department of Mathematics and Physics Hunan Institute of EngineeringHunan 411104China College of Science China Agricultural UniversityBeijing 100083China

This paper is a continuation of ＂Complex Dynamics in Physical Pendulum Equation with Suspension Axis Vibrations＂[1].In this paper,we investigate the existence and the bifurcations of resonant solution for ω0：ω：Ω ≈ 1：1：n,1：2：n,1：3：n,2：1：n and 3：1：n by using second-order averaging method,give a criterion for the existence of resonant solution for ω0：ω：Ω ≈ 1：m：n by using Melnikov＇s method and verify the theoretical analysis by numerical *** numerical simulation,we expose some other interesting dynamical behaviors including the entire invariant torus region,the cascade of invariant torus behaviors,the entire chaos region without periodic windows,chaotic region with complex periodic windows,the entire period-one orbits region;the jumping behaviors including invariant torus behaviors converting to period-one orbits,from chaos to invariant torus behaviors or from invariant torus behaviors to chaos,from period-one to chaos,from invariant torus behaviors to another invariant torus behaviors;the interior crisis;and the different nice invariant torus attractors and chaotic *** numerical results show the difference of dynamical behaviors for the physical pendulum equation with suspension axis vibrations between the cases under the three frequencies resonant condition and under the periodic/quasi-periodic *** exhibits many invariant torus behaviors under the resonant *** find a lot of chaotic behaviors which are different from those under the periodic/quasi-periodic ***,we did not find the cascades of period-doubling bifurcation.

关键词： Pendulum equation suspension axis vibrations averaging method Melnikov's method bifurcations chaos three frequencies resonances resonant solution