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Qinling Faunal Region-The Third Ordovician Faunal Region:International Correlation

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Acta Geologica Sinica(English Edition) 2000年第2期74卷 137-142页

作者： pei Fang Regional Geological Survey Party Henan Bureau of Geology and Mineral Exploration and DevelopmentPingdingshan 467021Henan

The Ordovician conodont faunal provinces were previously divided into the Midcontinent and Atlantic Faunal Regions situated respectively in low and high latitudes, where warm- and cold-water type conodont faunas flourished respectively. According to the international correlation this paper proposes the third Ordovician conodont faunal region—Qinling Faunal Region, in which cold-water conodont faunas were well developed in the Early to middle Middle Ordovician and warm-water conodont faunas were well developed in the late Middle and Late Ordovician, indicating that the Qinling Region was situated in high latitudes earlier and in low latitudes later. The origin was only due to plate movement. In the Qinling Region the time interval of the change of the conodont fauna from the cold- to warm-water type was 4 Ma (from 474 to 470 Ma), during which the fauna geographically spanned 40° of latitudes, with a movement velocity of nearly 1.12 m/a, indicating that the high-latitude plates were divorced and reduced in the late Middle Ordovician, while the low-latitude plates were converged and accreted. According to the features of the conodont faunas, the Qinling Faunal Region can be divided into the North Tarim, Wudang, Scandic and Pingliang provinces.

关键词： Midcontinent Faunal Region Altanic Faunal Region Qingling Faunal Region plate movement

Efficient Degradation of Cellulose in Its Homogeneously Aqueous Solution over 3D Metal-Organic Framework/Graphene Hydrogel Catalyst

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Chinese Journal of Chemical Physics 2016年第6期29卷 742-748,I0002页

作者： pei Huang Li-feng Yan DepartmentofChemicalPhysics iCHEMUniversityoFScienceandTechnologyofChinaHefei230026China

Catalytic degradation of cellulose to chemicals is an attracting topic today for the conver- sion of biomass, and the development of novel catalysts is a key point. Since metal-organic frameworks （MOFs） possess uniform, continuous, and permeable channels, they are valu- able candidate as catalysts. Here, a new 3D MOF/graphene catalyst was prepared by in situ growth of the zeolitic imidazolate frameworks （ZIF-8） nanoparticles inside the pore of an as-formed 3D reduced graphene oxide （rGO） hydrogel. The ZIF-8/rGO nanocomposite owns both micropores and mesopores with large specific surface area and plenty of acids sites, which is an idea catalyst for biomass degradation. Cellulose was dissolved in allmline aqueous solution at first, and then it was degraded efficiently over the new catalyst under hydrothermal condition. The conversion reaches 100% while the main products are formic acid with a maximum yield of 93.66%. In addition, the catalyst can be reused with high activity.

关键词： Graphene Metal-Organic framework Cellulose Catalyst Formic acid

Reduction of 1-3 mm Iron Ore by CO on Fluidized Bed

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Journal of Iron and Steel Research International 2011年第3期18卷 1-5页

作者： PANG Jian-ming GUO pei-min ZHAO pei The State Key Laboratory for Advanced Steel Processes and Products Central Iron and Steel Research InstituteBeijing 100081China

The reduction-degree of the sample increases and the utilization ratio of gas decreases when the reaction lasts longer time,which indicates that the reaction is faster at the beginning of reduction,while it becomes slower in subsequent *** higher the reaction temperature,the higher the utilization ratio of gas and the reduction-degree are,but the difference of utilization ratio among the different temperatures becomes smaller with *** utilization ratio of gas can reach about 8% and the reduction-degree is 80% for 20 min reduction at 850 ℃,indicating that the reduction reaction by CO is very fast at high *** higher the reaction temperature,the higher the apparent reaction rate constant is,but the difference of apparent reaction rate constant among the different temperatures becomes *** apparent activation energy is about 59.11 kJ/mol in the fluidized bed *** increase of reduction-degree with gas velocity shows quite good linearity,indicating that at high temperature even higher velocity of reducing gas can be used to improve the productivity of reactor when CO is used as reducing *** the increase of charge height,the metallization ratio and the reduction-degree decrease,but the utilization ratio of gas increases.

关键词： CO fluidized bed fine powder iron ore reduction-degree

Reduction Kinetics of Fine Iron Ore Powder in Mixtures of H_2-N_2 and H_2-H_2O-N_2 of Fluidized Bed

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Journal of Iron and Steel Research International 2015年第5期22卷 391-395页

作者： Jian-ming PANG pei-min GUO pei ZHAO Center of Efficient Utilization of Resources by Low-temperature Metallurgy China Iron and Steel Research Institute Group

Reduction kinetics of fine iron ore powder in different gas mixtures were investigated in high-temperature fluidized bed at a scale of kilograms. Influence of processing parameters, such as particle size, gas flow velocity, height of charge, temperature, compositions of gas mixture, and percentage of inert components, on reduction ki- netics was experimentally determined under the condition of fluidization. The equations for calculating instantaneous and average oxidation rates were deduced. It was found that an increasing H2 O percentage in the gas mixture could obviously decrease the reduction rate because the equilibrium partial pressure of H2 decreased with increasing content of Hz O in the gas mixture and then the driving force of reduction reaction was reduced. When the H2 content was high, .the apparent reaction rate was so rapid when the average size of iron ore fines was less than 1 mm that the re- action temperature can be as low as 750 ℃ ; when the average size of iron ore fines was more than 1 mm, a high re- action temperature of 800 ℃ was required. In addition, it was also found that the content of H2O should be less than 10% for efficient reduction.

关键词： hydrogen fluidized bed fine iron ore powder reduction kinetics

Modification of waste polyacrylonitrile fiber and its application as a filtrate reducer for drilling

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Petroleum Science 2015年第2期12卷 325-329页

作者： pei-Zhi Yu School of Engineering and Technology China University of Geosciences(Beijing)

Cationic polymer fluid loss additive （CPFL） was prepared by using the reaction of 2,3-epoxypropy- ltrimethyl ammonium chloride （EPTMAC）（as cationic reagent） with the amide group in the molecular structure of the sodium salt of partially hydrolyzed polyacrylonitrile fibers （HPAN-Na）. The chemical reaction was determined by studying the infrared absorption peaks of the materials and the products. The results proved that the cationic groups of EPTMAC were successfully grafted onto the HPAN molecular chain. The composition of the molecular chain of the product CPFL was determined by investigation and calculation of the elemental analysis results of the grafted HPAN and the final reaction product CPFL. The drilling fluid performance was evaluated, and the result showed that when the cation content was more than 0.27 mmol/g, the drilling fluid would have good resistance to fluid loss and to pollution from calcium chloride.

关键词： Acrylic fiber Cationic agents Fluid lossagent. Spectroscopy

SUBMERGED IMPINGING JETS WITHIN A FINITE WATER DEPTH

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Journal of Hydrodynamics 2002年第3期14卷 40-43页

作者： Liu, pei-Qing Hydraulics Lab. of High Speed Flows Sichuan Univ. Chengdu 610065 China Fluid Mech. Inst. Beijing Univ. of Aero. and Astron. Beijing 100083 China

By use of the sheet of laser light and the tracing particle technology, flow visualization tests of complex flow structures for submerged impinging jets within finite water depths are conducted. Typical flow patterns of submerged impinging jets are analysed by the singular topology method. In order to reveal the mechanism of these flows, the diffusive characteristics and turbulent fluctuations of submerged impinging jets are measured by the hot-film anemometer.

关键词： Anemometers Flow of fluids Flow visualization Lasers Turbulence

Characteristics and distribution of phosphorus in surface sediments of a shallow lake

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Journal of Environmental Sciences 2023年第2期124卷 50-60页

作者： Ziwei Long Zehua Ji Yuansheng pei State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China The Key Laboratory of Water and Sediment Sciences Ministry of EducationSchool of EnvironmentBeijing Normal UniversityBeijing 100875China

Phosphorus(P)in sediments plays an important role in shallow lake ecosystems and has a major effect on the lake *** mobility and bioavailability of P primarily depend on the contents of different P forms,which in turn depend on the sedimentary ***,sediment samples from Baiyangdian(BYD)lake were collected and measured by the Standards,Measurements,and Testing procedure and Phosphorus-31 nuclear magnetic resonance spectroscopy(31P NMR)to characterize different P forms and their relationships with sediment physicochemical *** P content in the sediments varied in different areas and had characteristics indicative of exogenous river *** P(334–916 mg/kg)was the dominant form of *** 31P NMR results demonstrated that orthophosphate monoesters(16–110 mg/kg),which may be a source of P when redox conditions change,was the dominant form of organic P(20–305 mg/kg).The distribution of P forms in each region varied greatly because of the effects of anthropogenic activities,and the regions affected by exogenous river input had a higher content of P and a higher risk of P *** component analysis indicated that P bound to Fe,Al,and Mn oxides and hydroxides(NaOH-P)and organic P were mainly derived from industrial and agricultural pollution,*** analysis indicated that increases in pH lead to the release of *** matter plays an important role in the organic P biogeochemical cycle,as it acts as a sink and source of organic P.

关键词： Sediment Phosphorus forms SMT 31P NMR

Effects of thermophoresis on Brownian coagulation of spherical particles over the entire particle size regime

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Particuology 2022年第8期20卷 8-17页

作者： Kaiyuan Wang pei Wang Suyuan Yu Institute of Applied Physics and Computational Mathematics Bejing 100094.China Center forCombustionEergy.Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energyand PowerEngineeringTsinghua UniversityBejing 100084.China Smoore International Holdings Ltd.Shenzhen 518102 China

In many energy and combustion *** experience large temperature gradients,which can affect the coagulation process due to *** study presents a rigorous theory of thermophoretically modified Brownian coagulation in the entire particle size *** theoretical derivations are based on the kinetictheory forthe free-molecular regime and the harmonic mean method for the transition *** coagulation kernels in different size regimes can be expressed as the basic Brownian coagulation kernel times an enhancement factor,The enhancement factor represents the coagulationrate enhancement induced by thermophoresis and is a function of specific dimensionless *** on the enhancement factor,the thermophoretic enhancement effects on particle coagulation are further analyzed under a wide range of gas and particle *** results show that thermophoretic enhancement effects are ignorable in the free-molecular regime,but need to be considered in the continuum regime and the transition *** addition,the enhancement effects increase significantly with increase of gas temperature and temperature gradient while decrease with increase of gas *** present study can improve understanding ofthermophoretic effects on Brownian coagulation in the entire size regime and provide a useful tool to calculate the coagulation rates in presence of thermophoresis.

关键词： Thermophoresis Brownian coagulation Enhancement factor Knudsen number

An intelligent approach for flight risk prediction under icing conditions

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Chinese Journal of Aeronautics 2023年第6期36卷 109-127页

作者： Guozhi WANG Haojun XU Binbin pei Graduate School Air Force Engineering UniversityXi'an 710038China Aviation Engineering School Air Force Engineering UniversityXi'an 710038China

Flight risk prediction is significant in improving the flight crew's situational awareness because it allows them to adopt appropriate operation strategies to prevent risk expansion caused by abnormal conditions,especially aircraft icing *** flight risk space representing the nonlinear mapping relations between risk degree and the three-dimensional commanded vector(commanded airspeed,commanded bank angle,and commanded vertical velocity)is developed to provide the crew with practical risk ***,the construction of flight risk space by means of computational flight dynamics suffers from certain defects,including slow computing ***,an intelligent approach for flight risk prediction is proposed to address these defects based on neural *** Basis Function Neural Network(RBFNN)is optimized using Adaptive Particle Swarm Optimization(APSO).To optimize both the parameters and the structure of APSO-RBFNN,a fitness function containing the training accuracy and network structure size is *** experimental results demonstrate that the flight risk predicted by APSO-RBFNN is very close to that obtained via computational flight *** average error(RMSE)is less than 10^(-1).The approach achieves a speedup close to 1000x compared with computational flight *** addition,some flight upset and recovery cases are presented to illustrate the efficiency of the intelligent approach for flight risk prediction.

关键词： Adaptive Particle Swarm Optimization(APSO) Flight risk assessment and prediction Flight risk space Icing conditions Radial Basis Function Neural Network(RBFNN)