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Innovative hydrophobic/hydrophilic perfluoropolyether(PFPE)/polyvinylidene fluoride(PVDF)composite membrane for vacuum membrane distillation

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Chinese Journal of Chemical Engineering 2022年第5期35卷 248-257页

作者： Jun Pan Xianli Xu Zhaohui Wang Shi-Peng Sun Zhaoliang Cui Lassaad Gzara Iqbal Ahmed Omar Bamaga Mohammed Albeirutty Enrico Drioli State Key laboratory of Materials-Oriented Chemical Engineering College of Chemistry and Chemical EngineeringNanjing Tech UniversityNanjing 210009China National Engineering research Center for Special Separation Membrane Nanjing Tech UniversityNanjing 210009China Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM) Nanjing Tech UniversityNanjing 210009China Center of Excellence in Desalination Technology King Abdulaziz UniversityJeddah 21589Saudi Arabia Mechanical Engineering Department King Abdulaziz UniversityJeddah 21589Saudi Arabia research Institute on Membrane Technology ITM-CNRVia Pietro Bucci 17/CRende 87036Italy

Though membrane distillation(MD)has gained more and more attention in the field of desalination,the wetting phenomenon was still a non-negligible *** this work,a method combined dip-coating and UV in situ polymerization for preparing hydrophobic/hydrophilic perfluoropolyether(PFPE)/polyvinylidene fluoride composite *** composite membrane consisted of a top thin hydrophobic coating layer and hydrophilic substrate *** terms of anti-wetting properties,contact angle and liquid entry pressure of all composite membranes(except for those based on 0.45μm)exceeded 160°and 0.3 MPa,*** particular,the desalination performance was tested in vacuum membrane distillation tests by feeding 3.5%(mass)saline solution(NaCl)at 60℃.The composite membranes with larger support pore size and lower PFPE content had higher membrane distillation *** for stability tests(testing the 0.22μm membrane coated by 5%(mass)PFPE),the highest MD flux29.08 kg·m^(-2)·h^(-1) and stable salt rejection(over 99.99%)during the *** that,the effects of coating material concentration and pore sizes of substrate membrane were also investigated for surface morphology and topography,porosity,mechanical strength and pore size *** work provided a simple and effective alternative to prepare excellent hydrophobic composite membranes for MD applications.

关键词： Desalination Membrane surface coating Composite membranes Anti-wetting Vacuum membrane distillation

Modeling nanoscale ice adhesion

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Acta Mechanica Solida Sinica 2017年第3期30卷 224-226页

作者： Senbo Xiao Jianying He Zhiliang Zhang NTNU Nanomechanical lab Department of Structural Engineering Norwegian University of Science and Technology (NTNU) Trondheim 7491 Norway

Anti-icing is crucial for numerous instruments and devices in low temperature circum- stance. One of the approaches in anti-icing is to reduce ice adhesion strength, seeking spontaneous de-icing processes by natural forces of gravity or by winds. In order to enable tai- lored surface icephobicity design, research requires a good theoretical understanding of the atomistic interacting mechanisms between water/ice molecules and their adhering substrates. Herein, this work focuses on using atomistic modeling and molecular dynamics simulation to build a nanosized ice-cube adhering onto silicon surface, with different contact modes of solid-solid and solid-liquid-solid patterns. This study provides atomistic models for probing nanoscale ice adhesion mechanics and theoretical platforms for explaining experimental results.

关键词： Anti-icing Atomistic modeling Molecular dynamics Adhesion Interface mechanics

Mechanism of thermoviscoelasticity driven solid-liquid interface reducing friction for polymer alloy coating

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Friction 2023年第9期11卷 1606-1623页

作者： Sheng TAN Yimin LUO Junhua YANG Wei WANG Xia LI Baoguang JIA Zhuangzhu LUO Guangan ZHANG School of Materials Sun Yat-sen UniversityShenzhen 518107China The 14th research Institute of China Electronics Technology Group Corporation Nanjing 210039China State Key laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

High-temperature ablation is a common failure phenomenon that limits the service life of the transmission parts on heavy-duty machines used in heavy load,high temperature,high shock conditions due to in-sufficient supply of lubricating oil and *** self-lubricating coatings prepared by inorganic,organic or organic-inorganic hybrid methods are prone to be oxidated at high temperatures to lose their friction reducing function,so that it is difficult to meet the engineering requirements of high-temperature *** design viscoelastic polymer coatings by a high-temperature self-lubricating and wear-resistant ***(PTFE,T_(m)=329℃)and polyphenylene sulfide(PPS,T_(g)=84℃,T_(m)=283℃)are used to prepare a PTFE/PPS polymer alloy *** the temperature increases from 25 to 300℃,the PTFE/PPS coating softens from glass state to viscoelastic state and viscous flow state,which is owing to the thermodynamic transformation characteristic of the PPS *** the friction coefficient(μ)decreased from 0.096 to 0.042 with the increasing of temperature from 25 to 300℃.The mechanism of mechanical deformation and surface morphology evolution for the PTFE/PPS coating under the multi-field coupling action of temperature(T),temperature–centrifugal force(T–F_(ω)),temperature–centrifugal force–shearing force(T–F_(ω)–F_(τ))were *** physical model of“thermoviscoelasticity driven solid–liquid interface reducing friction”is proposed to clarify the self-lubricating mechanism determined by the high-temperature viscoelastic properties of *** high-temperature adjusts the viscosity(η)of the coating,increases interface slipping and intensifies shear deformation(τ),reducing the friction *** result is expected to provide a new idea for designing anti-ablation coatings served in high temperature friction and wear conditions.

关键词： self-lubricating polymer coating viscoelastic state solid-liquid interface friction reduction hightemperature tribology

Mechanical Properties and Microstructure Characteris-tics of Laser Rapid Forming Rene88DT Superalloy

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稀有金属材料与工程 2011年第S4期40卷 278-282页

作者： Zhao Xiaoming1,2,Gong Shuili1,Lin Xin2,Chen Jing 2,Huang Weidong21Science and Technology on Power Beam Processes laboratory,AVIC Beijing Aeronautical Manufacturing Technology research In-stitute,Beijing 100024,China2State Key laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China AVIC Beijing Aeronaut Mfg Technol Res Inst Sci & Technol Power Beam Proc Lab Beijing 100024 Peoples R China Northwestern Polytech Univ State Key Lab Solidificat Proc Xian 710072 Peoples R China

Nickel-based superalloy Rene88DT,has been laser-deposited using laser rapid forming (LRF) *** mechanical properties and microstructure characteristics of LRF Rene88DT at 25℃ and 750℃ were *** results shows that both strength and ductility of LRF Rene88DT can be improved significantly by the integration of optimized heat treatment (solution treatment (1160℃,2h/AC) + aging (760℃,8h/AC)) and the HIP treatment(1160℃,2h/200MPa).25℃ tensile properties is comparable to that of the Powder Metallurgy *** 750℃ tensile strength and ductility are also comparable to those of the Powder Metallurgy standard,but the yield strength is still a little lower at 750℃.As compared with the as-deposited state,g' precipitates of LRF Rene88DT are evolved gradually to be spherical in shape and uniformly distribute in the g matrix after optimized heat treatment and HIP *** surface shows that crack initiates at the edge for all the samples of LRF Rene88DT after tensile *** deformation is found to be homogeneous in the whole *** phenomenon exists near the fracture surface,which corresponds with the superior strength and ductility of LRF Rene88DT.

关键词： laser rapid forming Rene88DT mechanical properties microstructure characteristics

Evidence for pore-filling gas hydrates in the sediments through morphology observation

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Chinese Journal of Chemical Engineering 2019年第9期27卷 2081-2088页

作者： Wenxiang Zhang Shuanshi Fan Yanhong Wang Xuemei Lang Kai Guo Jianbiao Chen Key lab of Enhanced Heat Transfer and Energy Conservation Ministry of Education School of Chemistry and Chemical Engineering South China University of Technology

To provide an evidence of natural gas hydrate occurrence state,a series of experiments on multiple growth and dissociation of 90.0%methane/10.0%propane hydrates at 1.3 MPa and 270.15 K were carried out in two sediments for morphology observation via a visible *** gas hydrate crystals were observed to form and grow on the surface of sediments at the initial *** the thermal decomposition,gas and liquid products had an unceasingly impact on the sediments,then gas/liquid–solid migration occurred,and a large number of cavitation *** the later growth and dissociation experiments,the gas hydrate particles were in suspension or supporting states in the interstitial pore space between the sediment particles,indicating that the gas hydrate displayed a pore-filling *** analyzing the distribution of gas hydrates and bubbles,it was found that the amount of gas hydrates distributed in the sediments was improved with multiple growth-dissociation cycle *** migration enhanced the sediment movement,which led to the appearance of the increasing quantity of gas bubbles in the sediments during *** affected the growth of the gas hydrates and the migration of sediment grains,which also restricted the accumulation of gas bubbles in the *** to the Raman analysis,the results showed that sII hydrates were formed for CH4 and C3H8 gas mixtures in different sediments and solutions with hydration number of 5.84–*** Salt restricted the access of gas into the hydrate cages.

关键词： Gas hydrate Sediments Growth Dissociation Pore-filling

Spray printing and encapsulated liquid metal as a highly reflective metallic paint for packing products

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Science China(Technological Sciences) 2019年第9期62卷 1577-1584页

作者： LIANG Shu-Ting WANG Hong-Zhang LIU Jing Department of Biomedical Engineering School of MedicineTsinghua UniversityBeijing 100084China College of Materials and Chemical Engineering Chongqing University of Arts and SciencesChongqing 402160China Beijing Key lab of CryoBiomedical Engineering and Key lab of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China

In this strategy, liquid metal(LM) with a shiny metallic luster and an excellent optical property, was introduced as a novel metallic paint and coating to packing products and achieved decorative effects. We report a straightforward method via spray printing to fabricate a consecutive ultra-thin LM film on various product substrates. Then, the flexible LM film was coated with a transparent varnish layer, which was rather convenient for the LM paint to be storing, using and transporting. The thicknesses(25 μm) and the shapes of LM paint were well controlled. The flop index(FI=105), and reflectance(R=88.8%) data of the LM metallic paint were characterized. The results indicated that the LM metallic paint could provide a sparkling appearance and an abounding glossy. The deoxidized LM has a pronounced positive influence on the surface roughness, appearance, reflectance,and metallic texture. The LM metallic paint was highly desirable for potential applications in automotive enamel, motorcycle,toy and high-quality industrial coatings in the near future.

关键词： liquid metal packing metallic sparkle paint fine atomization

Mechanism of NBTI Recovery under Negative Voltage Stress

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Chinese Physics Letters 2008年第9期25卷 3393-3396页

作者：曹艳荣胡仕刚马晓华郝跃 School of Microelectronics Xidian University Xi'an 710071 Key lab of Wide Band-Gap Semiconductor Materials and Devices Xi'an 710071

Recovery phenomenon is observed under negative gate voltage stress which is smaller than the previous degradation stress. We focus on the drain current to study the degradation and recovery of negative bias temperature instability （NBTI） with a real-time method. By this method, different recovery phenomena among different size devices are observed. Under negative recovery stress, the drain current gradually recovers for the large size devices and gets into recovery saturation when long recovery time is involved. For small-size devices, a step-like recovery of drain current is observed. The recovery of the drain current is mainly caused by the holes detrapping and tunnelling back to the channel surface which are trapped in oxide. The model of hole detrapping explains the recovery under negative voltage stress reasonably.

关键词： the power-law exponents precipitation durative abrupt precipitation change

Numerical simulations of multi-layer-liquid sloshing by multiphase MPS method

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Journal of Hydrodynamics 2021年第5期33卷 938-949页

作者： Xiao Wen Wei-wen Zhao De-cheng Wan Computational Marine Hydrodynamics lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

In this paper,a multiphase moving particle semi-implicit(MPS)method is developed by introduction of various multiphase models into the original MPS method for single-phase flows,and is then applied to the numerical simulations of two-layer-liquid and three-layer-liquid sloshing in a 2-D rectangular tank under different external *** validate the accuracy of the present multiphase MPS method,the qualitative and quantitative results,including wave profiles,interface elevations and impact pressures,are compared with experimental data and other numerical results,which show a good *** particular,the evolutions of free surface and phase interfaces are compared and an obvious discrepancy is found,indicating that the phase interfaces may suffer from complex deformations while the free surface keeps relatively ***,the different modes of phase interface are observed under different excitation ***,the violent sloshing of a three-layer-liquid system is simulated and the phenomenon of internal wave breaking is well captured,which mainly benefitted from the Lagrangian basis of MPS method and its advantage in multiphase flows with complex ***,the three-layer-liquid sloshing with a vertical baffle are simulated to investigate the suppressing effect of baffle on multi-layer-liquid sloshing.

关键词： Moving particle semi-implicit(MPS) multiphase flows multi-layer-liquid liquid sloshing

Numerical Simulation on Fluid Flow in Hot Metal Pretreatment

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Journal of Iron and Steel research(International) 2011年第S2期18卷 129-134页

作者： SHAO Pin, ZHANG Ting-an, LIU Yan, ZHAO Hong-liang, HE Ji-cheng (laboratory of Ecological Untilization of Multi-Metal Intergrown Ores of Education Ministry, Shenyang 110004, Liaoning, China) lab Ecol Untilizat Multimet Intergrown Ores Educ Shenyang 110004 Liaoning Peoples R China

Basing on the commercial CFD metho d ,several models are adopted to simulate water model. The numerical simulation results are in good agreement with the experimental data of water model under the same experimental conditions. Then the numerical simulation method is presented to investigate the flow field, the vortex on gas-liquid surface and the uniform mixing time in hot metal ladles. This research shows: the vortex depth increases with increasing of immersion depth and rotation speed; Overflow appears in N=120rpm and h=3.2m; the turbulent kinetic energy increases with increasing immersion depth and rotation speed; uniform mixing time decreases with the decreasing of immersion depth and the rotation speed of stirring ; the optimal uniform mixing time is 23.5s on the conditions of N=100rpm and h=3.2m within the allowable range.

关键词： KR vortex uniform mixing time turbulent kinetic energy numerical simulation