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Hierarchical Porous Polymer Beads Prepared by Polymerization-induced Phase Separation and Emulsion-template in a Microfluidic Device

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Chinese Journal of Polymer Science 2014年第12期32卷 1646-1654页

作者： Wei-cai Wang yan-xiong Pan kai Shi Chao Peng 姬相玲 State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

Porous polymer beads（PPBs） containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation（PIPS） and emulsion-template technique in a glass capillary microfluidic device（GCMD）. Fabrication procedure involved the preparation of water-in-oil emulsion by emulsifying aqueous solution into the monomer solution that contains porogen. The emulsion was added into the GCMD to fabricate the（water-in-oil）-in-water double emulsion droplets. The flow rate of the carrier continuous phase strongly influenced the formation mechanism and size of droplets. Formation mechanism transformed from dripping to jetting and size of droplets decreased from 550 μm to 250 μm with the increase in flow rate of the carrier continuous phase. The prepared droplets were initiated for polymerization by on-line UV-irradiation to form PPBs. The meso-macropores in these beads were generated by PIPS because of the presence of porogen and gigapores obtained from the emulsion-template. The pore morphology and pore size distribution of the PPBs were investigated extensively by scanning electron microscopy and mercury intrusion porosimetry（MIP）. New pore morphology was formed at the edge of the beads different from traditional theory because of different osmolarities between the water phase of the emulsion and the carrier continuous phase. The morphology and proportion of bimodal pore structure can be tuned by changing the kind and amount of porogen.

关键词： Porous polymer beads Hierarchical Polymerization-induced phase separation Emulsion-template Microfluidic device.

Lithiophilic Cu-Li_(2)O matrix on a Cu Collector to Stabilize Lithium Deposition for Lithium Metal Batteries

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Energy & Environmental Materials 2022年第4期5卷 1270-1277页

作者： Zhe Gong Cheng lian Pengfei Wang kai Huang kai Zhu Ke Ye Jun yan Guiling Wang Dianxue Cao Key Laboratory of Superlight Materials and Surface Technology of Ministry of Education College of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

Lithium metal anode is the most ideal candidate for next-generation energy storage ***,the uncontrolled dendrite growth,infinite volume expansion,and undesired side reactions lead to serious safety issues and hinder their potential ***,a pre-lithiation strategy is proposed to construct a high-lithiophilic Cu-Li_(2)O matrix on commercial Cu *** in situ-generated Li_(2)O promises adequate nucleation sites and strengthens solid electrolyte interphase and lateral lithium ***,the existence of 3D matrix reduces the local current *** synergy effect of Li_(2)O and Cu suppresses the growth of lithium *** a result,Cu-Li_(2)O matrix reveals an enhanced lithium plating/stripping behavior with Coulombic efficiency of 98.46%after 270 *** symmetrical cell assembled by Li-plated electrodes displays a prolonged lifespan of 1400 *** work demonstrates a scalable and effective approach for modified current collectors toward stable Li metal anode.

关键词： Cu-Li_(2)O matrix current collectors Li metal anodes SEI film

Unsteadiness control of laminar junction flows on pressure fluctuations

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Applied Mathematics and Mechanics(English Edition) 2019年第3期40卷 373-380页

作者： Jianhua LIU Shucheng ZHAI E.KUDASHEV Fangwen HONG kai yan China Ship Scientific Research Center National Key Laboratory on Ship Vibration & Noise Space Research Institute of Russian Academy of Sciences

Smoke-wire flow visualization is conducted carefully in a laminar junction to explore the physical behavior of laminar junction flows. The two-dimensional(2 D)velocity fields in the 30?plane of a laminar junction flow are acquired by a time-resolved particle image velocimetry(PIV) system at a frame rate of 1 kHz, based on which the unsteady fluctuating pressure fields can be calculated by the multi-path integration method proposed in the literature(GAND, F., DECK, S., BRUNET,V., and SAGAUT, P. Flow dynamics past a simplified wing body junction. Physics of Fluids, 22(11), 115111(2010)).A novel control strategy is utilized to attenuate the unsteadiness of the horseshoe vortices of the laminar junction flow, and the consequent effect on pressure fields is analyzed.

关键词： junction flow horseshoe vortex pressure fluctuation flow visualization

Density Functional Theory Study of Water Diffusion and Clustering on Pd(111)

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Chinese Journal of Structural Chemistry 2006年第8期25卷 909-914页

作者： CHEN Jin-Wen TU Xue-yan TIAN kai DAI Shu-Shan School of Chemical Science and Technology Yunnan University Kunming 650091 China School of Chemistry. and Biotechnology Yunnan Nationalities University Kunming 650031 China School of Chemistry and Chemical Engineering Hunan Universi of Science and Technology Xiangtan 411201 China

The internal structures as well as adsorption and hopping energies of monomers, dimers, trimers, tetramers, pentamers and hexamers of water on Pd（111） have been studied by density functional theory （DFT） plane-wave pseudopotential method which performs the firstprinciples quantum-mechanical calculations to explore the properties of crystals and surfaces in materials. Based on the calculations, we suppose that their absorption is via one water molecule for monomers, dimmers and trimers, but three water molecules for pentamers and hexamers. Moreover, there is one water molecule bonding with Pd atom by O atom in pentamers and hexamers, which explains why pentamers and hexamers are stable. The binding energies of polymers may be used to explain why the trimer comes close to two nearby monomers to form a stable pentamer instead of tetramer. And the difference of mobility of small water clusters is due to their different hopping energies.

关键词： density functional theory Pd(111) surface water diffusion and clustering binding energy hopping energy

Formation mechanism and control of MgO·Al_2O_3 inclusions in non-oriented silicon steel

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International Journal of Minerals,Metallurgy and Materials 2014年第11期21卷 1068-1076页

作者： yan-hui Sun Ya-nan Zeng Rui Xu kai-ke Cai School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

On the basis of the practical production of non-oriented silicon steel, the formation of Mg O·Al2O3 inclusions was analyzed in the process of ＂basic oxygen furnace（BOF） → RH → compact strip production（CSP）＂. The thermodynamic and kinetic conditions of the formation of Mg O·Al2O3 inclusions were discussed, and the behavior of slag entrapment in molten steel during RH refining was simulated by computational fluid dynamics（CFD） software. The results showed that the Mg O/Al2O3 mass ratio was in the range from 0.005 to 0.017 and that Mg O·Al2O3 inclusions were not observed before the RH refining process. In contrast, the Mg O/Al2O3 mass ratio was in the range from 0.30 to 0.50, and the percentage of Mg O·Al2O3 spinel inclusions reached 58.4% of the total inclusions after the RH refining process. The compositions of the slag were similar to those of the inclusions; furthermore, the critical velocity of slag entrapment was calculated to be 0.45 m·s^-1 at an argon flow rate of 698 L·min^-1, as simulated using CFD software. When the test steel was in equilibrium with the slag, [Mg] was 0.00024wt%–0.00028wt% and [Al]s was 0.31wt%–0.37wt%; these concentrations were theoretically calculated to fall within the Mg O·Al2O3formation zone, thereby leading to the formation of Mg O·Al2O3 inclusions in the steel. Thus, the formation of Mg O·Al2O3 inclusions would be inhibited by reducing the quantity of slag entrapment, controlling the roughing slag during casting, and controlling the composition of the slag and the Mg O content in the ladle refractory.

关键词： silicon steel steelmaking inclusions deoxidation slag entrapment thermodynamics kinetics

Adaptive fuzzy integral sliding mode velocity control for the cutting system of a trench cutter

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Frontiers of Information Technology & Electronic Engineering 2016年第1期17卷 55-66页

作者： Qi-yan TIAN Jian-hua WEI Jin-hui FANG kai GUO State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou 310027China

This paper presents a velocity controller for the cutting system of a trench cutter(TC). The cutting velocity of a cutting system is affected by the unknown load characteristics of rock and soil. In addition, geological conditions vary with time. Due to the complex load characteristics of rock and soil, the cutting load torque of a cutter is related to the geological conditions and the feeding velocity of the cutter. Moreover, a cutter's dynamic model is subjected to uncertainties with unknown effects on its function. In this study, to deal with the particular characteristics of a cutting system, a novel adaptive fuzzy integral sliding mode control(AFISMC) is designed for controlling cutting velocity. The model combines the robust characteristics of an integral sliding mode controller with the adaptive adjusting characteristics of an adaptive fuzzy controller. The AFISMC cutting velocity controller is synthesized using the backstepping technique. The stability of the whole system including the fuzzy inference system, integral sliding mode controller, and the cutting system is proven using the Lyapunov theory. Experiments have been conducted on a TC test bench with the AFISMC under different operating conditions. The experimental results demonstrate that the proposed AFISMC cutting velocity controller gives a superior and robust velocity tracking performance.

关键词： Cutting system, Electro-hydraulic system, Cutting velocity control, Adaptive fuzzy integral sliding mode control

Anisotropic coal permeability and its stress sensitivity

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International Journal of Mining Science and Technology 2019年第3期29卷 507-511页

作者： Zhiming yan kai Wang Jie Zang Chuan Wang Ang Liu Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources China University of Mining & TechnologyBeijing 100083China yangquan Coal Industry (Group) Co. LTDYangquan 045000China Faculty of Resource & Safety Engineering China University of Mining & TechnologyBeijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining & TechnologyBeijing 100083China

This paper focuses on anisotropy of coal permeability and its stress *** blocks were taken from Xinjing Coal Mine in yangquan Coal *** cores were then drilled along the strike,dip,and vertical *** permeabilities were measured with respect to stress by using a self-developed coal permeability measurement *** used samples exhibited significant permeability *** permeability along the strike direction was greatest among the three directions,the permeability along the vertical direction was the smallest,and the permeability along the dip direction was between the other two *** sensitivity of coal permeability to stress was transversely *** stress sensitivity coefficient was greater along the horizontal directions than along the vertical *** permeability exhibited anisotropic stress sensitivity due to anisotropy in Young’s modulus and *** results obtained in this study are useful for optimizing the arrangement of pre-drainage boreholes.

关键词： Coal permeability Anisotropy Stress sensitivity Gas drainage Experiment

Three-dimensional flow field simulation of steady flow in the serrated diffusers and nozzles of valveless micro-pumps

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Journal of Hydrodynamics 2019年第2期31卷 413-420页

作者： Ying-hua Xu Wei-ping yan kai-rong Qin Tun Cao School of Energy and Power Engineering Dalian University of TechnologyDalian 116024China School of Optoelectronic Engineering and Instrumentation Science Dalian University of TechnologyDalian 116024China

This paper presents a three-dimensional flow field simulation of the steady flows through diffusers and nozzles with straight or serrated-sided walls to analyze the effect of the channel structure on the flow *** pressure and velocity profiles in the diffusers and the nozzles as well as the net volumetric flow rate are *** simulation demonstrates that the pressure and velocity profiles in the serrated diffuser/nozzles are more complicated than those with the straight-sided wall,while the net steady flow rate with the straight-sided wall increases monotonically with the increase of the pressure difference,the steady flow rate with serrated sided walls increases gradually to reach a maximum and then decreases with the increase of the pressure *** results suggest that the number of the sawteeth plays a significant role in optimizing the design of serrated diffusers and nozzles for improving the transport efficiency of valveless micro-pumps.

关键词： Valveless micro-pump steady flow diffuser and nozzle serrated-sided wall three-dimensional flow field simulation

Low-carbon building heating system coupled with semiconductor radiation heating and distributed PV:A simulation analysis in two Chinese climate zones

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Building Simulation 2023年第7期16卷 1059-1079页

作者： yan Zhang kai Han Yongzhen Wang Wenjie Ji Lanlan Zhang Wei Zhang School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Innovation Center in Chongqing Beijing Institute of TechnologyChongqing 401120China Department of Energy and Power Engineering Tsinghua UniversityBeijing 100089China

Building is an important scenario for achieving global carbon peak and carbon neutrality goals,accounting for approximately 37%of global energy-related CO_(2) emissions in *** the meanwhile,the construction and operation of buildings was responsible for 36%of global energy consumption,of which 30%energy was used for space ***,this paper proposes a low-carbon building heating system that is coupled to a new semiconductor radiation heating unit and distributed rooftop photovoltaic to reduce carbon *** reveal its building heating characteristics,a dynamic model of heat transfer based on semiconductor low-temperature radiant heating is first established by analyzing the heat conduction,convection,and radiation models,and the uncertainty from both the distributed rooftop photovoltaic and building heating demand is considered in the building heating operation ***,a simulation model of a low-carbon building heating system is built in MATLAB/SIMULINK for two different climate zones in China(Beijing and Wuhan).When building and using the low-carbon building heating system stable for 30 years,the payback period is 5.2–8.2 years in Beijing and 6.4–11.6 years in *** with the traditional grid-powered heating system,the simulation revealed that the carbon emissions of Beijing and Wuhan during the heating season are reduced by 44.9%and 44.3%,respectively,and the corresponding building heating cost is saved by 62.1%and 57.8%.

关键词： radiation heating low-carbon building heating semiconductor distributed photovoltaic simulation optimization