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CFD simulation of smooth and T-abrupt exits in circulating fluidized bed risers

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Particuology 2010年第4期8卷 343-350页

作者： Xuezhi Wu Fan Jiang xiang Xu Yunhan xiao Key Laboratory of Advanced Energy and Power Institute of Engineering Thermophysics Chinese Academy ofSdences Beijing 100190 China Graduate University of the Chinese Academy ofSdences Beijing 100049 China

Gas-solid flow in circulating fluidized bed （CFB） risers depends not only on operating conditions but also on exit configurations. Few studies investigated the effects of exit configurations on flow structure using computational fluid dynamics （CFD）. This paper provides a 2D two-fluid model to simulate a cold bench-scale square cross-section riser with smooth and T-abrupt exits. The drag force between the gas and solid phases plays an important role in CFD. Since the drag force model based on homogeneous two- phase flow, such as the Wen-Yu correlation, could not capture the heterogeneous structures in gas-solid flow, the structure-dependent energy-minimization multi-scale （EMMS） drag force model （Wang, Ge, ＆ Li, 2008）, applicable for Geldart B particles （sand）, was integrated into the two-fluid model. The calculated axial solids hold-up profiles were respectively exponential curve for smooth exit and C-shaped curve for T-abrupt exit, both consistent with experimental data. This study once again proves the key role of drag force in CFD simulation and also shows the validity of CFD simulation （two-fluid model） to describe exit effects on ~as-solid flow in CFB risers.

关键词： T-abrupt exit Smooth exit Gas-solid flow CFBEMMS drag force model

Impacts of the COVID-19 pandemic on consumers’ food safety knowledge and behavior in China

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Journal of Integrative Agriculture 2020年第12期19卷 2926-2936页

作者： MIN Shi xiang Cheng ZHANG xiao-heng College of Economics and Management Huazhong Agricultural UniversityWuhan 430070P.R.China Institute of Agricultural Economics and Development Chinese Academy of Agricultural SciencesBeijing 100081P.R.China

This study assesses the impacts of the COVID-19 pandemic on Chinese residents’food safety knowledge and behavior,and explores the possible influence mechanism,namely,focus on media *** study is based on internet survey data of 1373 residents in China.A series of econometric models are developed to estimate food safety knowledge and behavior of *** the descriptive and econometric results indicate that the existence of COVID-19 cases in a community has a significantly positive effect on residents’food safety knowledge and *** focusing on food safety-related information tend to have higher food safety knowledge and practice food safety *** controlling the variable focused on food safety-related information,the marginal effects of the existence of COVID-19 cases in a community on residents’food safety knowledge and behavior significantly ***,the decrease in consumers’food safety knowledge is quite ***,the COVID-19 pandemic indeed improves Chinese residents’food safety knowledge and behavior,while focus on food safety-related information is an important mechanism for improving food safety ***,the estimation results of the simultaneous equations model reveal that consumers’food safety knowledge has a significant and positive effect on their food safety *** impacts of the COVID-19 pandemic on residents’food safety knowledge and behavior among different regions and income groups are *** findings of this study provide evidence that public health events could enhance residents’safety awareness and behavior,while residents’focus on relevant information plays an important role in improving knowledge and impacting behavior.

关键词： food safety knowledge behavior COVID-19

Preparation,Properties and Application of C/C-SiC Composites Fabricated by Warm Compacted-in situ Reaction

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Journal of Materials Science & Technology 2010年第3期26卷 283-288页

作者： Peng xiao Zhuan Li Zibing Zhu xiang Xiong State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China China Aviation Power Plant Research Institute Zhuzhou 412002 China

Carbon fibre reinforced carbon and SiC dual matrices composites （C/C-SiC） show superior tribological properties,high thermal shock resistance and good abrasive resistance,and they are promising candidates for advanced brake and clutch *** microstructure,mechanical properties,friction and wear properties,and application of the C/C-SiC composites fabricated by warm compacted-in situ reaction were *** results indicated that the composites were composed of 50-60 wt pct carbon,2-10 wt pct residual silicon and 30-40 wt pct silicon *** C/C-SiC brake composites exhibited good mechanical *** value of flexural strength and compressive strength could reach 160 and 112 MPa,*** impact strength was about 2.5 kJ·*** C/C-SiC brake composites showed excellent tribological performance,including high coefficient of friction （0.38）,good abrasive resistance （1.10 μm/cycle） and brake steadily on dry *** tribological properties on wet condition could be mostly *** silicon carbide matrix in C/C-SiC brake composites improved the wear resistance,and the graphite played the lubrication function,and right volume content of graphite was helpful to forming friction film to reduce the wear *** results showed that C/C-SiC composites fabricated by warm compacted-in situ reaction had excellent properties for use as brake materials.

关键词： C/C-SiC Ceramic-matrix composites Tribology Warm compacted-in situ reaction

Coordinated Planning for Fast Charging Stations and Distribution Networks Based on an Improved Flow Capture Location Model

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CSEE Journal of Power and Energy Systems 2023年第4期9卷 1505-1516页

作者： Shiqu xiao Xia Lei Tao Huang xiang Wang School of Electrical Engineering and Electronic Information Xihua UniversityChengdu 610039China. Department Ingegneria Elettrica Politecnico Di TorinoTorino 10129Italy

The increasing penetration of plug-in electric vehi-cles(PEVs)should lead to a significant reduction in greenhouse gas ***,the development of PEVs is limited by the lack of charging facilities,which is constrained by the coupled transportation-distribution *** paper presents a stochastic bi-level model for the optimal allocation of fast charging stations(FCSs)and distribution network expansion planning(DNEP).First,a sequential capacitated flow-capturing location-allocation model(SCFCLM)is proposed at the lower level to optimize the allocation of FCSs on the transportation ***-Carlo simulation(MCS)is utilized to estimate daily charging load ***,we propose an economic model for DNEP at the upper level,and the chance constrained method is employed to relax power flow constraints to address the uncertainties of *** experiments are conducted to illustrate the proposed planning *** influences of the flow capturing sequence and relaxed confidence level on the PEV charging load,FCS planning strategies and DNEP schemes are *** Terms-Coordinated planning,fast charging station,flow-capturing model,plug-in electric vehicle,stochastic bi-level model.

关键词： Coordinated planning fast charging station flow-capturing model plug-in electric vehicle stochastic bi-level model.

Modeling and Experimental Validation on Pressure Drop in a Reverse-flow Cyclone Separator at High Inlet Solid Loading

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Journal of Thermal Science 2011年第4期20卷 343-348页

作者： Wu Xuezhi Liu Jie Xu xiang xiao Yunhan Key Laboratory of Advanced Energy and Power （Institute of Engineering Thermophysics） Chinese Academy of Sciences Beijing 100190 Graduate University of Chinese Academy of Sciences Beijing 100190

High inlet solid loading is one of the most important features of cyclone separators in high density circulating fluidized beds （CFB）. In this work, the effect of high solid loading on pressure drop in a reverse-flow cyclone was experimentally studied. The particles used were sand and 2zAl203. Art extended range of inlet solid loadings （M）, up to 30 kg of solids/kg of air was tested at different inlet air velocities （Vin=16~24 m/s）, well beyond the solid loading range reported before. The experiments showed that, in the tested range of solid loadings, the cyclone pressure drop decreased dramatically with increasing solid loading when M〈7.5 kg/kg and then almost remained constant. A new semi-empirical model for predicting cyclone pressure drop was also developed. The calculated and experimental results showed good agreement for particle free flow and particle laden flow.

关键词： high inlet solid loading pressure drop reverse-flow cyclone modeling.

A first-principles study on electronic structures and elastic properties of metal dopedα-Fe(N)high nitrogen steel

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Journal of Iron and Steel Research International 2017年第1期24卷 103-110页

作者： Ji-chun Yang xiang-jun Liu Gui-xiao Jia xiao-yang Fu School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou 014010Inner MongoliaChina

The binding energies,electronic structures and elastic properties of Ti,V,Cr,Mn,Co,Ni and Mg dopedα-Fe（N）systems have been investigated using a first-principles *** calculated results show that the dopings of Ti,V,Cr and Co improve the stability ofα-Fe（N）,and the stability ofα-Fe（N）is slightly weakened by Mn and Ni,and the doping of Mg is *** Ti,V,Cr and Mn dopedα-Fe（N）systems in which the doping metals are on the left side of Fe in the element periodic table andα-Fe（N）systems doped by Co and Ni on the right side of Fe,their corresponding cohesive forces decrease with decreasing atomic radius of the doping *** obvious interaction exists among M3 d,Fe4s3p3d and N2 *** these doping systems,metal atoms lose electrons,while N gains *** of Ti,V,Cr and Mn inα-Fe（N）strengthen the interaction between N and the surrounding metals,and it is not apparent for the dopings of Co,Ni and *** calculations of Fe15 MN systems show that,except for the Fe15 MgN system,shear modulus G and Young modulus E of Fe15 MN systems are improved,and the bulk modulus Bslightly decreases,namely,total elastic properties are *** magnitude change rule of E reflecting the cohesive force between atoms is consistent with that for the binding energies.

关键词： First principle High nitrogen steel Metal nitride Electronic structure Elastic property

Massive gastric bleeding-perforation of pancreatic pseudocyst into the stomach: A case report and review of literature

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World Journal of Clinical Cases 2021年第2期9卷 389-395页

作者： Zhe Jin Yi-Wei xiang Qiu-Shi Liao xiao-Xu Yang Hui-Chao Wu bi-Guang Tuo Rui Xie Department of Gastroenterology Affiliated Hospital of Zunyi Medical UniversityZunyi 563003Guizhou ProvinceChina

BACKGROUND Pancreatic pseudocyst may cause serious gastrointestinal complications including necrosis,infection,and perforation of the gastrointestinal tract wall,but massive gastric bleeding is very *** We report a rare case of a 49-year-old man with life-threatening gastric bleeding from a pseudoaneurysm of the splenic artery perforating the stomach induced by pancreatic *** hospitalization,gastroscopy revealed a bare blood vessel in an ulcer-like depression of the greater gastric curvature,and computed tomography scan confirmed a pancreatic pseudocyst invading part of the spleen and gastric wall of the greater *** showed that the bare blood vessel originated from a pseudoaneurysm of the splenic *** bleeding was controlled by the trans-arterial embolization,the patient’s recovery was rapid and *** Massive gastrointestinal bleeding could be a rare complication of pancreatic pseudo aneurysm.

关键词： Gastric bleeding Pseudoaneurysm of the arteria lienalis Pancreatic pseudocyst Trans-arterial embolization Case report

Holographic technicolor model and dark matter

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Chinese Physics C 2020年第9期44卷 16-24页

作者： Yidian Chen xiao-Jun bi Mei Huang Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physics University of Chinese Academy of SciencesBeijing 100049China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

We investigate the strongly coupled minimal walking technicolor model(MWT)in the framework of a bottom-up holographic model,where the global SU(4)symmetry breaks into SO(4)*** the holographic model,we found that 125 GeV composite Higgs particles and small Peskin–Takeuchi S parameter can be achieved *** addition,the model predicts a large number of particles at the TeV scale,including dark matter candidates Technicolor Interacting Massive Particles(TIMPs).If we consider the dark matter nuclear spin-independent cross-section in the range of 10^−45∼10^−48cm^2,which can be detected by future experiments,the mass range of TIMPs predicted by the holographic technicolor model is 2∼4 TeV.

关键词： dark matter holography technicolor

Multicolor circularly polarized phosphorescence of axially chiral binuclear platinum(Ⅱ) complexes

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Science China Chemistry 2024年第11期67卷 3757-3766页

作者： Jintong Song Rui Zeng Hui xiao Hailiang Ni Zong-xiang Xu Haifeng xiang College of Chemistry and Materials Science Sichuan Normal UniversityChengdu 610068China College of Chemistry Sichuan UniversityChengdu 610064China Department of Chemistry Southern University of Science and TechnologyShenzhen 518000China

D-A charge transfer, including through-bond charge transfer and through-space charge transfer between two different electron donors(D) and electron acceptors(A), is a fundamental and powerful tool to tune the optical properties of organic dyes. Herein,we demonstrate a unique strategy to tune phosphorescence and circularly polarized luminescence properties of axially chiral binuclear Pt(Ⅱ) complexes through long-range charge transfer, even though these molecules have two totally identical segments on either side of the chiral core. The presence of axial chirality would break not only the symmetry of molecular structure and π-conjugation system but also the symmetry of charge distribution for long-range charge transfer. These binaphthyl-based Pt(Ⅱ)complexes bearing coordinated atoms far away from chiral axis exhibit no Pt-Pt interactions but colorful concentrationdependent phosphorescence with quantum yield up to 86.4% and could be applied as emitters in highly efficient solutionprocessed organic light-emitting diodes to achieve luminance, luminance efficiency, power efficiency, external quantum efficiency, and asymmetry factor up to 8.94 × 10^(3)cd m^(-2), 41.9 cd A-1, 18.8 lm W^(-1), 12.6% and 2.98 × 10^(-3), respectively. Therefore,the present work affords a new and simple way to utilize the inherently asymmetric advantage of chirality for the design of D-Abased organic dyes.

关键词： Pt(Ⅱ)complexes organic light-emitting diodes circularly polarized phosphorescence axial chirality