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Two Improvements on Numerical Simulation of 2-DOF Vortex-Induced Vibration with Low Mass Ratio

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China Ocean Engineering 2017年第6期31卷 764-772页

作者： KANG zhuang NI Wen-chi ZHANG Xu sun Li-ping Deepwater Engineering Research Center Harbin Engineering University Harbin 150001 China

Till now, there have been lots of researches on numerical simulation of vortex-induced vibration. Acceptable results have been obtained for fixed cylinders with low Reynolds number. However, for responses of 2-DOF vortex-induced vibration with low mass ratio, the accuracy is not satisfactory, especially for the maximum amplitudes. In Jauvtis and Williamson＇s work, the maximum amplitude of the cylinder with low mass ratio m＊=2.6 can reach as large as 1.5D to be called as the ＂super-upper branch＂, but from current literatures, few simulation results can achieve such value, even fail to capture the upper branch. Besides, it is found that the amplitude decays too fast in the lower branch with the RANS-based turbulence model. The reason is likely to be the defects of the turbulence model itself in the prediction of unsteady separated flows as well as the unreasonable setting of the numerical simulation parameters. Aiming at above issues, a modified turbulence model is proposed in this paper, and the effect of the acceleration of flow field on the response of vortex-induced vibration is studied based on OpenFOAM. By analyzing the responses of amplitude, phase and trajectory, frequency and vortex mode, it is proved that the vortex-induced vibration can be predicted accurately with the modified turbulence model under appropriate flow field acceleration.

关键词： 2-DOF vortex-induced vibration numerical simulation modified turbulence model acceleration

Properties of Aluminum Oxide (AlO_x) Barrier Coatings Deposited on Poly(Ethylene Terephthalate)(PET)Substrates by Reactive Magnetron Sputtering

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稀有金属材料与工程 2012年第S1期41卷 268-271页

作者： Liu zhuang Ma Xinxin sun Zhihui Xu Fangjun Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China Harbin Univ Commerce Harbin 150028 Peoples R China

The aluminum oxide(AlOx)coatings were deposited on poly(ethylene terephthalate)(PET)surface by reactive magnetron sputtering for improving its barrier *** O2 flux increasing,three modes including metallic mode,transition mode and oxide mode exist in *** properties of the aluminum oxide(AlOx)coatings prepared at different modes were ***,the influences of oxygen flux on the stoichiometry,structure,gas permeation of the coatings were *** chemical composition of AlOx films fabricated in transition mode is different as oxygen flux varies slightly,and the gas barrier property is better as the stoichiometry is closer to 1.5 with oxygen flux *** coating uniformity,roughness and particle size depend remarkably upon oxygen *** coatings deposited at oxide mode have a good barrier performance to oxygen and water,and the permeability to oxygen decreases by sixty times and water vapor ten times compared with uncoated

关键词： permeation barrier aluminum oxide magnetron sputtering poly(ethylene terephthalate)(PET)

Rechargeable solid-state Li-air batteries： a status report

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Rare Metals 2018年第6期37卷 459-472页

作者： Chu-Shu Yang KangNing Gao XiaoPing Zhang zhuang sun Tao Zhang The State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of Sciences Shanghai 200050 China University of Chinese Academy of Sciences Beijing 100049China

The theoretical specific energy of lithium-air battery is as high as 3436 ***^-1, and the possible achieved value may reach 600-700 ***^-l, which enables this energy storage system as an important propulsion power sources for electric vehicles with the driving range of 500-800 km. Currently, Li-air batteries are facing main challenges at stability, efficiency, applicability and safety. In particular, from a practical view of point, the Li-air batteries should be operated directly in ambient air. Solid-state battery system is the best avenue to eventually solve these main issues. At the heart of the solid state, Li-air technology is the solid-state Li^＋-conducting ceramic material. Developing solid-state lithium-air batteries （SSLAB） can solve the problem of applicability fundamentally and circumvent the safety issues completely, and it is also an important avenue to improve the stability of the battery system. In this paper, we provide a systematical review of the progress in the cell construction, the regulation of the electrode/electrolyte interface, the cell assembly, the electrochemical performance and the mechanism for the SSLAB. In every section, the contributions of the recent research progress in the main challenges and the remained questions will be commented. Based on these reviews, we attempt to propose some alternative approaches for the next stage and suggest a development prospective for the SSLAB.

关键词： Solid-state lithium-air batteries Solid-state Li^+-conducting ceramic material Interfacial regulation technology In situ formation of passivation film Frameworks structure

Source apportionment for urban PM_(10) and PM_(2.5) in the Beijing area

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Chinese Science Bulletin 2007年第5期52卷 608-615页

作者： ZHANG Wei GUO JingHua sun YeLe YUAN Hui zhuang GuoShun zhuang YaHui HAO ZhengPing Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Center for Atmospheric Environmental Study Department of Chemistry Beijing Normal University Beijing 100875 China

Airborne particulate matter (PM2.5 and PM10) samples were collected at the Beijing Normal University sampling site in the urban area of Beijing, China in dry and wet seasons during 2001―2004. Concen-trations of 23 elements and 14 ions in particulate samples were determined by ICP-AES and IC, re-spectively. Source apportionment results derived from both Positive Matrix Factorization (PMF) and Chemical Mass Balance (CMB) models indicate that the major contributors of PM2.5 and PM10 in Beijing are: soil dust, fossil fuel combustion, vehicle exhausts, secondary particulate, biomass burning and some industrial sources. We have identified both regional common sources, such as vehicular emis-sions, particulate of secondary origin and biomass burning, as well as country-specific problems, such as sand storms and soil dust that should be addressed for effective air quality control.

关键词：北京地区城区空气颗粒物 PM10 PM2.5 污染源

Corrosion behavior of the friction-stir-welded joints of 2A14-T6 aluminum alloy

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International Journal of Minerals,Metallurgy and Materials 2015年第6期22卷 627-638页

作者： Hai-long Qin Hua Zhang Da-tong sun Qian-yu zhuang School of Materials Science and Engineering University of Science and Technology Beijing The Welding Institute Chongqing Changan Automobile Co. Ltd.

The corrosion behavior of friction-stir-welded 2A14-T6 aluminum alloy was investigated by immersion testing in immersion exfoliation corrosion（EXCO） solution. Electrochemical measurements（open circuit potential, potentiodynamic polarization curves, and electrochemical impedance spectroscopy）, scanning electron microscopy, and energy dispersive spectroscopy were employed for analyzing the corrosion mechanism. The results show that, compared to the base material, the corrosion resistance of the friction-stir welds is greatly improved, and the weld nugget has the highest corrosion resistance. The pitting susceptibility originates from the edge of Al-Cu-Fe-Mn-Si phase particles as the cathode compared to the matrix due to their high self-corrosion potential. No corrosion activity is observed around the θ phase（Al2Cu） after 2 h of immersion in EXCO solution.

关键词： aluminum alloys friction stir welding joints corrosion in-situ observation

Reduction of die roll height in duplex gears through a sheet-bulk metal forming method

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Advances in Manufacturing 2019年第1期7卷 42-51页

作者： Xiao-Long sun Xin-Cun zhuang Feng-Chun Yang Zhen Zhao Institute of Forming Technology and Equipment School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200030 People's Republic of China National Engineering Research Center of Die & Mold CAD Shanghai Jiao Tong University Shanghai 200030 People's Republic of China

In the existing shearing processes for fabricating parts such as duplex gears, die roll is difficult to avoid. Accordingly, a method based on sheet-bulk metal forming for fabricating a duplex gear with extremely small die roll in one stroke is proposed in the current work. The process could be divided into three stages according to the forming features: upsetting and shearing stage, lateral extrusion stage, and local filling stage. The die roll appeared in the shearing stage, which could be reduced in the subsequent extrusion and local filling stages. To reveal the underground mechanism, material flows under two situations, as a key factor to influence the forming quality, were compared and investigated. The results revealed that by controlling material flow, one could avoid the defects and reduce the die roll.

关键词： Die roll Duplex gear part Sheet-bulk metal forming Lateral extrusion Material flow

Self-Powered Piezo-Supercapacitors Based on ZnO@Mo-Fe-MnO_(2)Nanoarrays

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Energy & Environmental Materials 2024年第4期7卷 304-314页

作者： Luo sun Zhiguo Ye Xinyuan Peng Shaojie zhuang Duosheng Li Zhong Jin School of Materials Science and Engineering Nanchang Hangkong University696#FengHeNan RoadNanchang 330063China State Key Laboratory of Coordination Chemistry MOE Key Laboratory of Mesoscopic ChemistryMOE Key Laboratory of High Performance Polymer Materials and TechnologyJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

The development of self-charging supercapacitor power cells(SCSPCs)has profound implications for smart electronic devices used in different ***,we epitaxially electrodeposited Mo-and Fe-codoped MnO_(2)films on piezoelectric ZnO nanoarrays(NAs)grown on the flexible carbon cloth(denoted ZnO@Mo-Fe-MnO_(2)NAs).A self-charging supercapacitor power cell device was assembled with the Mo-and Fe-codoped MnO_(2)nanoarray electrode and poly(vinylidenefluoride-co-trifluoroethylene)(PVDF-Trfe)piezoelectric film doped with BaTiO_(3)(BTO)and carbon nanotubes(CNTs)(denoted PVDF-Trfe/CNTs/BTO).The self-charging supercapacitor power cell device exhibited an energy density of 30μWh cm^(-2)with a high power density of 40 mW cm^(-2)and delivered an excellent self-charging performance of 363 mV(10 N)driven by both the piezoelectric ZnO nanoarrays and the poly(vinylidenefluoride-co-trifluoroethylene)piezoelectric film doped with BaTiO_(3)and carbon *** intriguingly,the device could also be self-charged by 184 mV due to residual stress alone and showed excellent energy conversion efficiency and low self-discharge *** work illustrates for the first time the self-charging mechanism involving electrolyte ion migration driven by both electrodes and films.A comprehensive analysis strongly confirmed the important contribution of the piezoelectric ZnO nanoarrays in the self-charging process of the self-charging supercapacitor power cell *** work provides novel directions and insights for the development of selfcharging supercapacitor power cells.

关键词： MnO_(2) piezoelectric self-charging supercapacitors ZnO nanoarray

The numerical simulation of a new double swirl static mixer for gas reactants mixing

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Chinese Journal of Chemical Engineering 2020年第9期28卷 2438-2446页

作者： Zhuokai zhuang Jingtian Yan Chenglang sun Haiqiang Wang Yuejun Wang Zhongbiao Wu Key Laboratory of Environment Remediation and Ecological Health Ministry of EducationCollege of Environmental&Resources ScienceZhejiang UniversityHangzhou310058China Zhejiang Provincial Engineering Research Centre of Industrial Boiler&Furnace Flue Gas Pollution Control Hangzhou 310058China College of Control Science and Engineering Zhejiang UniversityHangzhou 310027China Zhejiang Tianlan Environmental Protection Technology Co.Ltd Hangzhou 311202China

For the nitrogen oxide removal processes,high performance gas mixer is deeply needed for the injection of NH3 or *** this study,a new type of double swirl static mixer in gas mixing was investigated using computational fluid dynamics(CFD).The results obtained using Particle Image Velocimetry(PIV)correlated well with the results obtained from *** comparisons in pressure loss between the experimental results and the simulation results showed that the model was suitable and accurate for the simulation of the static *** process conditions and design were *** L/D equaled 4,coefficient of variation(COV)was<5%.The inlet velocity did not affect the distributions of turbulent kinetic *** terms of both COV and pressure loss,the inner connector is important in the design of the static *** nozzle length should be set at 4 *** both COV and pressure loss into consideration,the optimal oblique degree is *** averaged kinetic energy changed according to process conditions and *** new static mixer resulted in improved mixing performance in a more compact *** new static mixer is more energy efficient compared with other SV static ***,the double swirl static mixer is promising in gas mixing.

关键词： CFD PIV Gas mixing Double swirl static mixer Pressure loss

Prediction-Based Thunderstorm Path Recovery Method Using CNN-BiLSTM

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Intelligent Automation & Soft Computing 2023年第8期37卷 1637-1654页

作者： Xu Yang Ling zhuang Yuqiang sun Wenjie Zhang School of Electronics and Information Engineering Nanjing University of Information Science and TechnologyNanjing210044China Department of Electrical and Computer Engineering University of AlbertaEdmontonAB T6G 2R3Canada CCCC Highway Consultants Co. Ltd.Beijing100101China School of Geographical Sciences Nanjing University of Information Science and TechnologyNanjing210044China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China

The loss of three-dimensional atmospheric electric field(3DAEF)data has a negative impact on thunderstorm *** paper proposes a method for thunderstorm point charge path *** on the relation-ship between a point charge and 3DAEF,we derive corresponding localization formulae by establishing a point charge localization ***,point charge movement paths are obtained after fitting time series localization ***,AEF data losses make it difficult to fit and visualize ***,using available AEF data without loss as input,we design a hybrid model combining the convolutional neural network(CNN)and bi-directional long short-term memory(BiLSTM)to predict and recover the lost *** paths are not present during sunny weather,we propose an extreme gradient boosting(XGBoost)model combined with a stacked autoencoder(SAE)to further determine the weather conditions of the recovered ***,historical AEF data of known weathers are input into SAE-XGBoost to obtain the distribution of predicted values(PVs).With threshold adjustments to reduce the negative effects of invalid PVs on SAE-XGBoost,PV intervals corresponding to different weathers are *** recovered AEF is then input into the fixed SAE-XGBoost *** paths need to be fitted is determined by the interval to which the output PV *** results confirm that the proposed method can effectively recover point charge paths,with a maximum path deviation of approximately 0.018 km and a determination coefficient of 94.17%.This method provides a valid reference for visual thunderstorm monitoring.

关键词： Thunderstorm point charge atmospheric electric field(AEF) recovery