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Journal of Hydrodynamics 2021年第2期33卷 243-258页

作者： feng pan Li-zhong Mu Ying He Chao-jie Wang Shi-xiong Zhou School of Energy and Power Engineering Dalian University of TechnologyDalian 116024China

A thermal-hydrodynamic coupling model is used to investigate the interplay between the wall temperature distribution and the bubble departure during the nucleate boiling *** boiling process is modeled as the combination of three subprocesses:the transient heat conduction process in the solid heater,the evaporation of the microlayer underneath the bubble,and the bubble dynamics in the two-phase bulk fluid *** moving bubble interface is captured by the volume of fluid method in the OpenFOAM *** proposed model is validated against the experimental results of the boiling process of the water on an Indium Tin Oxide *** predicted results agree well with related measurements in the *** the validation,the effects of the boiling heat flux on the bubble departure period are *** results show that the bubble departure period decreases with the increase of the applied heat *** heat flux will cause irregularity in the departure periods for successive bubbles due to the influence of the wake flow evoked by the rising ***,the influence of the bubble contact angle on the boiling heat-transfer performance is *** is confirmed that the bubble departure diameter increases with the increase of the contact angle,meanwhile,the average wall temperature decreases with the increase of the contact angle.

关键词： Nucleate boiling thermal-hydrodynamic coupling simulation microlayer evaporation contact angle wall temperature distribution

Improving the Performance of Thermoelectric Materials by Atomic Layer Deposition-based Grain Boundary Engineering

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Chinese Journal of Structural Chemistry 2020年第5期39卷 831-837页

作者： LI Shuan-Kui ZHU Wei-Ming XIAO Yin-Guo pan feng School of Advanced Materials Peking University Shenzhen Graduate SchoolShenzhen 518055China

Thermoelectric materials can directly achieve the conversion between heat and electricity,providing a clean and reliable way to alleviate energy ***,the wide use of thermoelectric materials is subjected to their low energy conversion *** boundary engineering is considered as an effective strategy to improve thermoelectric performance,particularly for the most polycrystalline thermoelectric materials in bulk ***,the precise controlling over the microstructure and composition of grain boundary at atomic scale has been achieved by atomic layer deposition(ALD)technology,which has been confirmed in various thermoelectric materials,such as Bi2Te2.7Se0.3,Bi0.4Sb1.6Te3,and ***,it is demonstrated that the decoupling between three key thermoelectric parameters,*** coefficient,electrical conductivity and thermal conductivity,can be realized by ALD-based grain boundary ***,these key parameters can be optimized simultaneously toward the desired direction,which is extremely important for improving the thermoelectric *** this review,the relevant progress on the grain boundary engineering by ALD-based strategy is reviewed and some prospects are proposed.

关键词： grain boundary engineering atomic layer deposition thermoelectric materials

A laser synthesis of vanadium oxide bonded graphene for high-rate supercapacitors

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Journal of Energy Chemistry 2020年第10期29卷 174-178页

作者： Jun Tang Linfei Zhang Xiongwei Zhong Xinghui Wang feng pan Baomin Xu School of Advanced Materials Peking University Shenzhen Graduate SchoolPeking UniversityShenzhen 518055GuangdongChina Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055GuangdongChina Institute of Micro/Nano Devices and Solar Cells School of Physics and Information EngineeringFuzhou UniversityFuzhou 350108FujianChina

Graphene is a type of promising electrode material for high-energy and high-power density supercapacitors,but its electrochemical performance is greatly limited by the restacking *** this work,we reported a facile approach to synthesis graphene with chemically bonded vanadium oxide(VOx)nanoparticles and demonstrated that chemically-bonded VOxnanoparticles can effectively prevent the graphene sheets from restacking and hence improve the electrochemical *** capacitance of VOxbonded graphene increases to 272 F/g compared to 183 F/g of pristine graphene in 1 M H3PO4 aqueous electrolyte at 2 A/*** VOx-bonded graphene also showed improved rate capability in both H3PO4 and ionic liquid *** capacitance retention increases to 54.5%from 28.5%at 100 A/g(compare to2 A/g)in H3PO4 and increases to 65.1%from 46.3%at 2 A/g(compare to 0.2 A/g)in neat ionic liquid.A high energy density of 84.4 Wh/kg is obtained within the voltage window of 4 V in ionic *** at a high-power density of 1000 W/kg,the VOx-bonded graphene shows a high energy density of 47.3 Wh/kg.

关键词： Supercapacitors Restacking Vanadium oxides Laser reduced graphene

Regulated polarization degree of upconversion luminescence and multiple anti-counterfeit applications

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Rare Metals 2024年第5期43卷 2172-2183页

作者： Dong-Ping Wen Ping Chen Yi Liang Xiao-Ming Mo Cao-feng pan Center On Nanoenergy Research Guangxi Key Laboratory for Relativistic AstrophysicsSchool of Physical Science and TechnologyGuangxi UniversityNanning 530004China Key Laboratory of Micronano Energy and Sensor CAS Center for Excellence in NanoscienceBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 100140China

Polarization upconversion luminescence(PUCL)of lanthanide ions(Ln^(3+))has been widely used in single particle tracking,microfluidics detection,three-dimensional displays,and so ***,no effective strategy has been developed for modulating *** we report a strategy to regulate PUCL in Ho^(3+)-doped NaYF4single nanorods based on the number of upconversion *** constructing a multiphoton upconversion system for Ho^(3+),we regulate the degree of polarization(DOP)of PUCL from 0.590 for two-photon luminescence to 0.929 for three-photon upconversion luminescence(UCL).Furthermore,our strategy is verified from cross-relaxation between Ho^(3+)and Yb^(3+),excitation wavelength,excitation power density,and local site *** this regulation strategy of PUCL has also been achieved in Tm^(3+),with the DOP ranging from 0.233 for two-photon luminescence to 0.925 for four-photon UCL Besides,multi-dimensional anti-counterfeiting display has been explored with *** work provides an effective strategy for regulating PUCL and also provides more opportunities for the development of polarization display optical encoding,anti-counterfeiting,and integrated optical devices.

关键词： Polarization upconversion luminescence Degree of polarization Population density of excited state Number of upconversion photons Polarization anti-counterfeitingdisplay

Understanding groundwater table using a statistical model

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Water Science and Engineering 2018年第1期11卷 1-7页

作者： Shao-feng Yan Shuang-en Yu Yu-bai Wu De-feng pan Jia-gen Dong Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil-Water Environment in Southern China Ministry of EducationHohai UniversityNanjing 210098China Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute Wuhan 430064China Jiangsu Water Conservancy Research Institute Nanjing 210017China Jiangsu Coastal Water Conservancy Research Institute Dongtui 224200China Jiangsu Province Hydrology and Water Resources Investigation Bureau Nanjing 210008China

In this study, a statistical model was established to estimate the groundwater table using precipitation, evaporation, the river stage of the Liangduo River, and the tide level of the Yellow Sea, as well as to predict the groundwater table with easily measurable climate data in a coastal plain in eastern China. To achieve these objectives, groundwater table data from twelve wells in a farmland covering an area of 50 m ~ 150 m were measured over a 12-month period in 2013 in Dongtai City, Jiangsu Province. Trend analysis and correlation analysis were conducted to study the patterns of changes in the groundwater table. In addition, a linear regression model was established and regression analysis was conducted to understand the relationships between precipitation, evaporation, river stage, tide level, and groundwater table. The results are as follows：（1） The groundwater table was strongly affected by climate factors （e.g., precipitation and evaporation）, and river stage was also a significant factor affecting the groundwater table in the study area （p 〈 0.01, where p is the probability value）. （2） The groundwater table was especially sensitive to precipitation. The significance of the factors of the groundwater table were ranked in the following descending order： precipitation, evaporation, and river stage. （3） A triple linear regression model of the groundwater table, precipitation, evaporation, and river stage was established. The linear relationship between the groundwater table and the main factors was satisfied by the actual values versus the simulated values of the groundwater table （R^2 = 0.841, where R^2 is the coefficient of determination）.

关键词： Groundwater table Precipitation Evaporation Climate factors Regression statistics Coastal plain

New fcc Phase Formed in Immiscible Fe-Cu System by Solid State Diffusion

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Chinese Physics Letters 1992年第12期9卷 663-666页

作者： LIU Baixin pan feng TAO Kun Department of Meterials Science and Engineering Tsinghua UniversityBeijing 100084 Center of Condensed Matter and Radiation Physics CCAST(World Laboratory) Beijing 100080

Fe_(75)Cu_(25) nano-multilayers were prepared by alternative deposition of pure Fe and Cu metals and then annealed in situ in transmission electron microscopy to investigate the structural phase transformation.A new phase was formed in the Fe-Cu multilayers by interdiffusion at 820℃ for about I0min and was identified to be of fcc structure with a lattice parameter of 0.854±0.005nm.

关键词： Solid Diffusion annealed

Exact solution of U(5)–O(6) transitional description in interacting boson model with two-particle and two-hole configuration mixing

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Chinese Physics C 2020年第6期44卷 95-102页

作者： Lianrong Dai feng pan Ziwei feng Yu Zhang Sai Cui JPDraayer Department of Physics Liaoning Normal UniversityDalian 116029China Department of Physics and Astronomy Louisiana State UniversityBaton RougeLA 70803-4001USA

The exact solution of the U(5)-O(6)transitional description in the interacting boson model with twoparticle and two-hole configuration mixing is derived based on the Bethe ansatz *** Bethe ansatz equations are provided to determine the model’s eigenstates and corresponding eigen-energies.N=2 and N=4 cases are considered as examples to demonstrate the solution *** an example of the application,some low-lying level energies and B(E2)ratios of 108Cd are fitted and compared with the corresponding experimental data.

关键词： configuration mixing shape coexistence exactly solvable models

Preparation and Characterization of Nanosized Titania Sensing Film

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稀有金属材料与工程 2006年第A3期35卷 200-202页

作者： Ximing Wang Junying Zhang feng pan Weichang Hao Tianmin Wang Center of Materials Physics and Chemistry School of Science Beihang University Beijing 100083 China

Nanosized titania sensing films were prepared by sol-gel process and the microstructure was characterized. Influence of various factors on the morphologies of the films were studied in *** order to obtain films with high surface area,Y^(3+),Ce^(3+) and Fe^(3+) were doped in the titania *** titania sol was dispersed in a polymeric solution to get nanosized and porous *** electron microscope (SEM),atom force microscope (AFM),and x-ray diffraction (XRD) were used to characterize the titania ***,AFM figures indicated that the grain size decreased from about 150 nm to 20 nm when the concentration of additions changed from 0 at% to 55 at% and the film was porous with the grain size less than 30 nm when the titania sol was dispersed in a polymeric solution even when the calcination temperature increased up to 850℃.

关键词： titania sensing film dopant gas-sensing

Using bidirectional links to improve peer-to-peer lookup performance

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第6期7卷 945-951页

作者： JIANG Jun-jie TANG Fei-long pan feng WANG Wei-nong Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai 200030 China Network Center Shanghai Jiao Tong University Shanghai 200030 China

Efficient lookup is essential for peer-to-peer networks and Chord is a representative peer-to-peer lookup scheme based on distributed hash table (DHT). In peer-to-peer networks, each node maintains several unidirectional application layer links to other nodes and forwards lookup messages through such links. This paper proposes use of bidirectional links to improve the lookup performance in Chord. Every original unidirectional link is replaced by a bidirectional link, and accordingly every node becomes an anti-finger of all its finger nodes. Both theoretical analyses and experimental results indicate that these anti-fingers can help improve the lookup performance greatly with very low overhead.

关键词： Distributed hash table (DHT) Peer-to-peer Lookup performance

Transmission Electron Microscopy as a Powerful Tool for Investigating Lithium-ion Battery Materials

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Chinese Journal of Structural Chemistry 2019年第12期38卷 2015-2019页

作者： LIN Cong LI Jian-Yuan WANG Chong-Min pan feng School of Advanced Materials Peking UniversityShenzhen Graduate SchoolShenzhen 518055China Environmental Molecular Sciences Laboratory Pacific Northwest National LaboratoryRichlandWashington 99352USA

Transmission electron microscopy(TEM) stands out as one of the most powerful tools for characterizing materials at multiple scales and dimensions. This unique technique has nowadays been widely employed in investigating the lithium-ion battery(LIB) materials. The present perspective paper focuses on several LIB related aspects that are recently revealed by using TEM. Finally, we present outlook on the future directions of TEM for LIB research and development.

关键词： transmission electron microscopy lithium-ion batteries structures properties