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Pricing Model of Multiattribute Derivatives Based on Mixed Process
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作者 田军 彭灿 刘源 《Journal of Modern Transportation》 2000年第2期198-204,共7页
By Analyzing the behavior and character of derivative security, the authors established a pricing model of multiattribute derivative security whose underlying asset pricing process is a mixed process, and obtained a n... By Analyzing the behavior and character of derivative security, the authors established a pricing model of multiattribute derivative security whose underlying asset pricing process is a mixed process, and obtained a new model for option pricing of multiattribute derivatives based on mixed process, and improved some original results. 展开更多
关键词 pricing model multiattribute derivatives mixed process
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Enhanced nitrogen removal at low temperature with mixed anoxic/oxic process
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作者 Xiang-kun Li Ying-jun Yang +2 位作者 Gai-ge Liu Dou-dou Sun Xiao-chen Ma 《Water Science and Engineering》 EI CAS CSCD 2023年第1期67-75,共9页
Different hydraulic retention times(HRTs)were tested in a mixed anoxic/oxic(A/O)system at 5C and 10C to investigate the effects of HRT and carrier on nitrogen removal in wastewater at low temperatures.The results show... Different hydraulic retention times(HRTs)were tested in a mixed anoxic/oxic(A/O)system at 5C and 10C to investigate the effects of HRT and carrier on nitrogen removal in wastewater at low temperatures.The results showed that the addition of the fillers improved the treatment effect of each index in the system.With an optimal HRT of 7.5 h at 5C,the removal efficiencies of NHþ4-N and total nitrogen(TN)reached 91.2%and 75.6%,respectively.With an HRT of 6 h at 10C,the removal efficiencies of NHþ4-N and TN were 96.7%and 82.9%,respectively.The results of high-throughput sequencing showed that the addition of the suspended carriers in the aerobic zone could improve the treatment efficiency of nitrogen at low temperatures.The microbial analysis indicated that the addition of the suspended carriers enhanced the enrichment of nitrogen removal bacteria.Nitrospira,Nitrotoga,and Nitrosomonas were found to be the bacteria responsible for nitrification,and their relative concentrations on the biofilm at 5C and 10C accounted for 98.11%,92.79%,and 69.98%of all biological samples,respectively. 展开更多
关键词 Domestic sewage Low temperature mixed A/O process Nitrogen removal Bacterial community structure
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CONTINUOUS TIME MIXED STATE BRANCHING PROCESSES AND STOCHASTIC EQUATIONS 被引量:1
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作者 Shukai CHEN Zenghu LI 《Acta Mathematica Scientia》 SCIE CSCD 2021年第5期1445-1473,共29页
A continuous time and mixed state branching process is constructed by a scaling limit theorem of two-type Galton-Watson processes.The process can also be obtained by the pathwise unique solution to a stochastic equati... A continuous time and mixed state branching process is constructed by a scaling limit theorem of two-type Galton-Watson processes.The process can also be obtained by the pathwise unique solution to a stochastic equation system.From the stochastic equation system we derive the distribution of local jumps and give the exponential ergodicity in Wasserstein-type distances of the transition semigroup.Meanwhile,we study immigration structures associated with the process and prove the existence of the stationary distribution of the process with immigration. 展开更多
关键词 mixed state branching process weak convergence stochastic equation system Wasserstein-type distance stationary distribution
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On the sub-mixed fractional Brownian motion 被引量:10
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作者 El-Nouty Charles Zili Mounir 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2015年第1期27-43,共17页
Let {S t H, t ≥ 0) be a linear combination of a Brownian motion and an independent sub-fractional Brownian motion with Hurst index 0 〈 H 〈 1. Its main properties are studied. They suggest that SH lies between the ... Let {S t H, t ≥ 0) be a linear combination of a Brownian motion and an independent sub-fractional Brownian motion with Hurst index 0 〈 H 〈 1. Its main properties are studied. They suggest that SH lies between the sub-fractional Brownian motion and the mixed fractional Brownian motion. We also determine the values of H for which SH is not a semi-martingale. 展开更多
关键词 mixed Gaussian processes sub-fractional Brownian motion no stationary increments semi-martingales convexity.
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Use of two-stage dough mixing process in improving water distribution of dough and qualities of bread made from wheat–potato flour 被引量:4
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作者 YIN Jian CHENG Li +4 位作者 HONG Yan LI Zhao-feng LI Cai-ming BAN Xiao-feng GU Zheng-biao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2021年第1期300-310,共11页
The two-stage dough mixing process was innovated to improve the qualities of bread made from potato flour(PF) and wheat flour at a ratio of 1:1(w/w). The final dough was first prepared from wheat flour before being ad... The two-stage dough mixing process was innovated to improve the qualities of bread made from potato flour(PF) and wheat flour at a ratio of 1:1(w/w). The final dough was first prepared from wheat flour before being added with PF. The effects of the method on enhancing the dough qualities were verified, and the distribution of water in gluten-gelatinized starch matrix of the doughs was investigated. We observed that the bread qualities were improved, as reflected by the increase of specific volume from 2.26 to 2.96 m L g^–1 and the decrease of crumb hardness from 417.93 to 255.57 g. The results from rheofermentometric measurements showed that the dough mixed using the developed mixing method had higher maximum dough height value, time of dough porosity appearance, and gas retention coefficient, as well as enhanced gluten matrix formation compared to that mixed by the traditional mixing method. The results from low-field nuclear magnetic resonance confirmed that the competitive water absorption between gluten and gelatinized starch could restrict the formation of gluten network in the dough mixed using the traditional mixing process. Using the novel mixing method, gluten could be sufficiently hydrated in stage 1, which could then weaken the competitive water absorption caused by gelatinized starch in stage 2;this could also be indicated by the greater mobility of proton in PF and better development of gluten network during mixing. 展开更多
关键词 gelatinized starch gluten network potato flour water distribution two-stage dough mixing process
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Study on mixing and segregation behaviors in particulate fluidized bed system for mineral processing 被引量:2
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作者 Sahu S.N. Sahu A.K. Biswal S.K. 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第3期459-464,共6页
In order to identify the mixing and segregation behaviors in a mineral processing operation, present study aimed on the hydrodynamics of solid–liquid fluidization. The study was carried out in a fluidization column w... In order to identify the mixing and segregation behaviors in a mineral processing operation, present study aimed on the hydrodynamics of solid–liquid fluidization. The study was carried out in a fluidization column with tapings at different height of the bed to collect the sample. The binary particles considered in this study are hematite(4800 kg/m3) and quartz(2600 kg/m3) at different size fractions in the range of average size 87×10^(-6)m to 400×10^(-6)m. It is observed that for various binary mixtures, both quartz and hematite particles share the equal composition by mass(50%) at a particular height of fluidized bed, referred as ‘‘locus point'' of mixing. Study indicates that the mixing zone volume will increase for a continuous fluidized bed plant operation. It is observed that the number of locus points varies from 1 to 3 signifying their dependency on the size ratios of binary mixture. Whenever, the difference in terminal velocity between quartz and hematite particles approaches to zero, mixing is enhanced.Further, the present study is extended to find the segregation index for the different size ratios of quartz and hematite particles. It is evident that depending on the size ratios, various regions such as complete segregation, partial mixing and complete mixing can be observed. 展开更多
关键词 Liquid-solid fluidization Mixing Segregation Locus point Mineral processing
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Analysis of micro vortex metallization and introduction of evaluation factor in mixing process
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作者 赫俊国 魏希柱 +1 位作者 姜涛 张杰 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第2期185-188,共4页
To improve the mixing efficiency in water purification or wastewater treatment process and understand the mechanism of mass transfer,and a suitable evaluation factor is introduced to evaluate the efficiency of mixing ... To improve the mixing efficiency in water purification or wastewater treatment process and understand the mechanism of mass transfer,and a suitable evaluation factor is introduced to evaluate the efficiency of mixing process.The diffusion mass transfer under turbulent condition is investigated based on dynamic and mathematical analysis.The results indicate that submicroscopic diffusion is the rate-limiting step in mass transfer,and the inertia effect of micro vortex causes the phase mixing.An excellent efficiency can be obtained by controlling the scale of micro vortex within millimeter.Furthermore,a new indicator named mixing factor(IH)is proposed to evaluate the efficiency of mixing processes,which is more feasible than conventional evaluation methods,because of its connection of mixing extent with energy consumption. 展开更多
关键词 mixing process micro vortex mixing efficiency mass transfer evaluating indicator
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Measurement of intensity difference squeezing via non-degenerate four-wave mixing process in an atomic vapor
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作者 于旭东 孟增明 张靖 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第9期415-420,共6页
We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the pr... We report the measurement of the intensity difference squeezing via the non-degenerate four-wave mixing process in a rubidium atomic vapor medium. Two pairs of balanced detection systems are employed to measure the probe and the conjugate beams, respectively. It is convenient to get the quantum shot noise limit, the squeezed and the amplified noise power spectra. We also investigate the influence of the input extra quadrature amplitude noise of the probe beam. The influence of the extra noise can be minimized and the squeezing can be optimized under the proper parameter condition. We measure the -3.7-dB intensity difference squeezing when the probe beam has a 3-dB extra quadrature amplitude noise. This result is slightly smaller than -4.1 dB when the ideal coherent light (no extra noise) for the probe beam is used. 展开更多
关键词 four-wave mixing process intensity difference squeezing self-balanced detection
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Hydrochemistry of the Mixed Dead Sea-Red Sea Water under Different Impoundment Scenarios as a Time Dependent State
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作者 J. Abu-Qubu O. Rimawi +2 位作者 A. Anbar T. Alebous Z. S. H. Abu-Hamatteh 《Journal of Geoscience and Environment Protection》 2022年第1期94-108,共15页
The expected water mixing process between Red/Dead Sea water during the proposed conveyance projects is the main target of this research. The project will ensue transporting Red Sea water to recover and maintain certa... The expected water mixing process between Red/Dead Sea water during the proposed conveyance projects is the main target of this research. The project will ensue transporting Red Sea water to recover and maintain certain level of the Dead Sea, mostly will reach <span><span><span style="font-family:;" "=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">-</span></span></span></span><span style="font-family:;" "="">395</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">m. It is found that, the two different water bodies with different EC values or different densities (salinities) are relatively divided by stable plane. This plane is defined as the BARZACH PLANE. In this study, the mixing process occurred between the Red Sea with the Dead Sea waters, located at 20</span><span style="font-family:;" "="">% </span><span style="font-family:;" "="">-</span><span style="font-family:;" "=""> </span><span style="font-family:;" "="">24% of the Dead Sea column depth based on the Barzach Plane level. During a laboratory experimental work, it is found that the mixed Red/Dead Sea water evaporates in a high rate until certain level where the solution attains oversaturated conditions with different dissolved solids. At this stage, a thin layer of solids suddenly formed and floated at the surface of the dense brine. The salinity of the captured water is so dense that floated salt layer cannot be dissolved. In addition, the formed floated salt layer at the surface prevents the below captured water to evaporate and at this stage, stalactites start to form until the excess dissolved solids are not oversaturated with any mineral.</span> 展开更多
关键词 HYDROCHEMISTRY Dead Sea Red Sea Brine Water Mixing process Barzach Plan JORDAN
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Rheological properties of a multiscale granular system during mixing of cemented paste backfill:A review 被引量:3
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作者 Cuiping Li Xue Li Zhu’en Ruan 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第8期1444-1454,共11页
The technology of cemented paste backfill(CPB)is an effective method for green mining.In CPB,mixing is a vital process aiming to prepare a paste that meets the non-stratification,non-segregation,and non-bleeding requi... The technology of cemented paste backfill(CPB)is an effective method for green mining.In CPB,mixing is a vital process aiming to prepare a paste that meets the non-stratification,non-segregation,and non-bleeding requirements.As a multiscale granular system,homogenization is one of the challenges in the paste-mixing process.Due to the high shearing,high concentration,and multiscale characteristics,paste exhibits complex rheological properties in the mixing process.An overview of the mesomechanics and structural evolution is presented in this review.The effects of various influencing factors on the paste's rheological properties were investigated,and the rheological models of the paste were outlined from the macroscopic and mesoscopic levels.The results show that the mechanical effects and structural evolution are the fundamental factors affecting the rheological properties of the paste.Existing problems and future development trends are presented to change the practice where the CPB process comes first and the theory lags. 展开更多
关键词 cemented paste backfill RHEOLOGY mixing process MESOMECHANICS structural evolution
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Warm water wake off northeast Vietnam in the South China Sea 被引量:2
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作者 YAN Yunwei CHEN Changlin LING Zheng 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2014年第11期55-63,共9页
Due to orographic blockage, a weak wind wake occurs in summer off northeast Vietnam in the South China Sea. Under the wind wake, warm water is observed from both high-resolution satellite data and hydrographic observa... Due to orographic blockage, a weak wind wake occurs in summer off northeast Vietnam in the South China Sea. Under the wind wake, warm water is observed from both high-resolution satellite data and hydrographic observations. The wake of warm water forms in June, continues to mature in July and August, starts to decay in September, and disappears in October. The warm water wake also shows robust diurnal variation – it intensifies during the day and weakens in the night. Warm water wakes can be generated through wind-induced mixing and thermal(latent heat flux) processes. In this paper, a mixed layer model is used to evaluate the relative importance of the two processes on seasonal and diurnal timescales, respectively. The results demonstrate that thermal processes make a greater contribution to the wake than wind-induced mixing processes on a seasonal timescale, while the warm water wake is dominated by wind-induced mixing processes on a diurnal timescale. 展开更多
关键词 warm water wake wind-induced mixing processes thermal processes seasonal timescale diurnal timescale northeast Vietnam South China Sea
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Seasonal and spatial variations in rare earth elements and yttrium of dissolved load in the middle,lower reaches and estuary of the Minjiang River,southeastern China 被引量:1
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作者 ZHU Xuxu GAO Aiguo +5 位作者 LIN Jianjie JIAN Xing YANG Yufeng ZHANG Yanpo HOU Yuting GONG Songbai 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2018年第3期700-716,共17页
A bstract With the aim of elucidating the spatial and seasonal behaviors of rare earth elements(REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower... A bstract With the aim of elucidating the spatial and seasonal behaviors of rare earth elements(REEs), we investigated the dissolved REE concentrations of surface water collected during four seasons from middle, lower reaches and estuary of the Minjiang River, southeastern China. The results display that the REE abundances in Minjiang River, ranging from 3.3–785.9 ng/L, were higher than those of many of the major global rivers. The total REE concentrations(∑REE) were seasonally variable, averaging in 5 937.30, 863.79, 825.65 and 1 065.75 ng/L during second highest flow(SHF), normal flow(NF), low flow(LF) and high flow(HF) season, respectively. The R_(( L/M)) and R_((H/M)) ratios reveal the spatial and temporal variations of REE patterns, and particularly vary apparently in the maximum turbidity zone and estuary. REE patterns of dissolved loads are characterized by progressing weaker LREEs-enrichment and stronger HREEsenrichment downstream from middle reaches to estuary during all four seasons. Comparing with NF and LF seasons, in which REE patterns are relatively flat, samples of SHF season have more LREE-enriched and HREE-depleted patterns that close to parent rocks, while samples of HF season are more LREEs-depleted and HREE-enriched. REE fractionations from the middle to lower reaches are stronger in the SHF and HF seasons than those in NF and LF seasons. Generally, spatial and seasonal variations in REE abundance and pattern are presumably due to several factors, such as chemical weathering, mixture with rainfall and groundwater, estuarine mixing, runoff, biological production and mountain river characters, such as strong hydrodynamic forces and steep slopes. The highest Gd/Gd* always occurs at north ports during all four seasons, where most of the large hospitals are located. This suggests Gd anomalies are depended on the density of modern medical facilities. Y/Ho ratios fl uctuate and positively correlate to salinity in estuary, probably because of the geochemical behavior differences between Y and Ho. 展开更多
关键词 rare earth elements(REEs) Minjiang River estuarine mixing process dissolved load online pre-concentration system
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Numerical study and acceleration of LBM-RANS simulation of turbulent flow 被引量:1
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作者 Shuli Shu Ning Yang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第1期31-42,共12页
The coupled models of LBM (Lattice Boltzmann Method) and RANS (Reynolds-Averaged Navier-Stokes) are more practical for the transient simulation of mixing processes at large spatial and temporal scales such as crud... The coupled models of LBM (Lattice Boltzmann Method) and RANS (Reynolds-Averaged Navier-Stokes) are more practical for the transient simulation of mixing processes at large spatial and temporal scales such as crude oil mixing in large-diameter storage tanks. To keep the efficiency of parallel computation of LBM, the RANS model should also be explicitly solved; whereas to keep the numerical stability the implicit method should be better for PANS model. This article explores the numerical stability of explicit methods in 2D cases on one hand, and on the other hand how to accelerate the computation of the coupled model of LBM and an implicitly solved RANS model in 3D cases. To ensure the numerical stability and meanwhile avoid the use of empirical artificial lim- itations on turbulent quantities in 2D cases, we investigated the impacts of collision models in LBM (LBGK, MRT) and the numerical schemes for convection terms (WENO, TVD) and production terms (FDM, NEQM) in an explic- itly solved standard k-e model. The combination of MRT and TVD or MRT and NEQM can be screened out for the 2D simulation of backward-facing step flow even at Re = 107. This scheme combination, however, may still not guarantee the numerical stability in 3D cases and hence much finer grids are required, which is not suitable for the simulation of industrial-scale processes.Then we proposed a new method to accelerate the coupled model of LBM with RANS (implicitly solved). When implemented on multiple GPUs, this new method can achieve 13.5-fold accelera- tion relative to the original coupled model and 40-fold acceleration compared to the traditional CFD simulation based on Finite Volume (FV) method accelerated by multiple CPUs. This study provides the basis for the transient flow simulation of larger spatial and temporal scales in industrial applications with LBM-RANS methods. 展开更多
关键词 Lattice Boltzmann Method Reynolds-Averaged Navier-Stokes Graphic processing Units mixing transient simulation
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Numerical simulation for fluids mixing within seafloor hydrothermal sulfide deposit:taking the Trans-Atlantic Geo-Traverse (TAG) field for example
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作者 LI Huaiming ZHAI Shikui +2 位作者 TAO Chunhui YU Zenghui CHU Fengyou 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2010年第1期33-41,共9页
The formation mechanism of the large hydrothermal sulfide deposit is a complex geological process involving many controlling factors. Mixing between hydrothermal fluid and seawater plays a key role in this process. Th... The formation mechanism of the large hydrothermal sulfide deposit is a complex geological process involving many controlling factors. Mixing between hydrothermal fluid and seawater plays a key role in this process. The results of the Ocean Drilling Program (ODP) indicate that mixing of the evolved seawater and hydrothermal fluid, which is wildly developed within the Trans-Atlantic Geo-Traverse (TAG) hydrothermal deposit, governs the internal structure and chemical compositions of the deposit to great extent. Taking the TAG field for example, the mixing processes of hydrothermal fluid with the seawater heated to different extent are calculated, so as to discuss the impact of hydrothermal fluid/seawater mixing on the formation process of the sulfide deposit. The results indicate that: (1) mixing between the heated seawater and hydrothermal fluid derived from the deep deposit is largely responsible for the wild precipitation of anhydrite within the TAG hydrothermal deposit; (2) 330-310℃ is a special temperature range in the mixing process; (3) the mixing and hydrothermal processes in different zones of the TAG hydrothermal deposit (TAG-1, TAG-2 and TAG-5, etc.) have been discussed based on the simulated results. 展开更多
关键词 hydrothermal sulfide deposit mixing process TAG hydrothermal field numerical simulation
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Pointwise Convergence of a Nonparametric Estimator of Regression in a Measurable Space Used in Contingent Valuation Method
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作者 Taibi-Hassani Salima Dimitri Laroutis S. L. Adigaw-E-Touck 《Journal of Mathematics and System Science》 2015年第5期188-195,共8页
The Contingent Valuation Method is used to evaluate individual preferences for a change concerning a public non-market resource or property. The objective is to build a nonparametric forecasting model of an individual... The Contingent Valuation Method is used to evaluate individual preferences for a change concerning a public non-market resource or property. The objective is to build a nonparametric forecasting model of an individual's Willingness To Pay according to geographical location. Within this framework, an estimator (of type Nadaraya-Watson) is proposed for the regression of the variable related to geolocation. The specific characteristics of the location variable lead us to a more general regression model than the traditional models. Results are established for convergence of our estimator. 展开更多
关键词 Regression nonparametric estimation mixing process almost complete convergence contingent valuation method.
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Effect of kerosene injection states on mixing and combustion characteristics in a cavity-based supersonic combustor 被引量:1
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作者 Xu LIU Peibo LI +6 位作者 Fei LI Hongbo WANG Mingbo SUN Chao WANG Yixin YANG Dapeng XIONG Yanan WANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第4期308-320,共13页
It has been found that the static pressure distribution along the axial direction of liquid kerosene is lower than that of the gaseous kerosene under the same flow condition and overall equivalent ratio from previous ... It has been found that the static pressure distribution along the axial direction of liquid kerosene is lower than that of the gaseous kerosene under the same flow condition and overall equivalent ratio from previous studies.To further investigate this phenomenon,a compressible two-phase parallel simulation method is utilized to analyze the mixing and combustion characteristics of gaseous and liquid kerosene jets in a cavity-based supersonic combustor.The numerical results are consistent with the experiments and demonstrate that gaseous injection leads to a cavity shear layer that dives deeper into the cavity,forming two recirculation zones in the front and rear of the cavity.In contrast,the cavity shear layer is closer to the mainstream during liquid injection,and only a large recirculation zone is formed in the rear of the cavity.As a result of the cavity shear layer and the recirculating flow,the fuel vapor of gaseous injection accumulates in the front of the cavity,while for the liquid injection,the fuel vapor disperses in the cavity,cavity shear layer,and the region above,and the rear of the cavity has a higher fuel vapor concentration than the front.This unique fuel distribution causes the combustion area to be concentrated in the cavity during the gaseous injection but dispersed inside and downstream of the cavity during the liquid injection.As a result,forming a thermal throat under the same conditions is more challenging during liquid injection,and the generated static pressure distribution is lower than that during the gaseous injection. 展开更多
关键词 Gaseous injection Liquid injection Mixing process Combustion Supersonic flow
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Nonparametric estimation for stationary and strongly mixing processes on Riemannian manifolds
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作者 Amour T.Gbaguidi Amoussou Freedath Djibril Moussa +1 位作者 Carlos Ogouyandjou Mamadou Abdoul Diop 《Communications in Mathematics and Statistics》 SCIE 2022年第4期599-621,共23页
In this paper,nonparametric estimation for a stationary strongly mixing and manifoldvalued process(X_(j))is considered.In this non-Euclidean and not necessarily i.i.d setting,we propose kernel density estimators of th... In this paper,nonparametric estimation for a stationary strongly mixing and manifoldvalued process(X_(j))is considered.In this non-Euclidean and not necessarily i.i.d setting,we propose kernel density estimators of the joint probability density function,of the conditional probability density functions and of the conditional expectations of functionals of X_(j)given the past behavior of the process.We prove the strong consistency of these estimators under sufficient conditions,and we illustrate their performance through simulation studies and real data analysis. 展开更多
关键词 Riemannian manifolds Nonparametric estimation Kernel density estimation Stationary and strongly mixing processes Strong consistency
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Numerical Simulation of the High-Boosting Influence on Mixing,Combustion and Emissions of High-Power-Density Engine 被引量:3
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作者 WANG Can YUE Zongyu +3 位作者 ZHAO Yuanyuan YE Ying LIU Xinlei LIU Haifeng 《Journal of Thermal Science》 SCIE EI CAS CSCD 2023年第3期933-946,共14页
Future high-power-density engines require high level of intake boost.However,the effects of boosting on mixing,combustion and emissions in existing studies are inconsistent.In this paper,the mixing,combustion and emis... Future high-power-density engines require high level of intake boost.However,the effects of boosting on mixing,combustion and emissions in existing studies are inconsistent.In this paper,the mixing,combustion and emission characteristics with intake pressures of 100-400 kPa at low,medium and high loads are studied.The results show that the increase of intake pressures is conducive to the enhancement of air entrainment,while the air utilization ratios are reduced,thus requiring injection pressure to be optimized to effectively improve the mixing.For the intake pressures of 100 kPa,the average chemical reaction path is low-temperature reaction route,while the path of higher intake pressures is dominated by high-temperature pyrolysis.For soot emissions,when the equivalence ratio is lower than 0.175,the oxygen in the cylinder is suficient,so the effect of temperature decrease is more significant,which leads to the increase of soot emissions with the increase of intake pressures.Otherwise,the effect of increasing oxygen concentration is more significant,so soot decreases accordingly.When the peak of global temperature is lower than 1800 K,the effect of the increase of oxygen concentration is more dominant,so the NO_(x)emission increases with the increase of intake pressures.Otherwise,the rule of NOxemissions is consistent with temperature changes. 展开更多
关键词 high-power-density engines high boosting mixing process combustion process EMISSIONS
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Supersonic Flow Structure in the Entrance Part of a Mixing Chamber of 2D Model Ejector 被引量:8
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作者 Vaclav Dvorak Pavel Safarik 《Journal of Thermal Science》 SCIE EI CAS CSCD 2003年第4期344-349,共6页
The paper deals with experimental and numerical results of investigation into supersonic and transonic flow past a two-dimensional model ejector. Results of optical measurements show a flow structure and flow paramete... The paper deals with experimental and numerical results of investigation into supersonic and transonic flow past a two-dimensional model ejector. Results of optical measurements show a flow structure and flow parameter development in the entrance part of the mixing chamber of the ejector. Numerical results are obtained by means of both the straight solution of shock waves in supersonic flow field using classical relations of parameters of shock waves and the Fluent 6 program. Results of numerical solutions are compared with experimental pictures of flow fields. Flow structure development in the mixing chamber is analysed in detail. 展开更多
关键词 supersonic ejector shock waves shear layers mixing process boundary layer separation.
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Spatial and temporal variations of two cyanobacteria in the mesotrophic Miyun reservoir, China 被引量:10
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作者 Ming Su Jianwei Yu +2 位作者 Shenling Pan Wei An Min Yang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第2期289-298,共10页
Spatial variations in phytoplankton community within a large mesotrophic reservoir (Miyun reservoir, North China) were investigated in relation to variations in physico-chemical properties, nutrient concentrations, ... Spatial variations in phytoplankton community within a large mesotrophic reservoir (Miyun reservoir, North China) were investigated in relation to variations in physico-chemical properties, nutrient concentrations, temperature and light conditions over a 5 month period in 2009. The dynamics of phytoplankton community was represented by the dominance of cyanobacteria through summer and fall, following with a short term dominance of chlorophyta in late fall, and a relatively high abundance of diatom in October; on the other hand, maximum phytoplankton biomass was recorded in the north shallow region of Miyun reservoir with a higher nutrients level. Particular attention was paid to the impacts of environmental conditions on the growth of two cyanobacteria genera, the toxin-producing Microcystis and the taste & odor-producing Oscillatoria. Microcystis biomass was in general greatly affected by water temperature and mixing depth/local water depth ratio in this reservoir, while the Oscillatoria biomass in the surface and middle layers was greatly affected by total dissolved phosphorus, and that in the bottom layer was related with the Secchi depth/local water depth ratio. Abundant Oscillatoria biomass was observed only in late September when Microcystis biomass decreased and allowed sufficient light go through. 展开更多
关键词 phytoplankton community succession Microcystis sp. Oscillatoria sp. mesotrophic reservoir total dissolved phosphorus water transparency mixing process
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