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Support surface pore structures matter: Effects of support surface pore structures on the TFC gas separation membrane performance over a wide pressure range

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Chinese Journal of Chemical Engineering 2019年第8期27卷 1807-1816页

作者： Mengqi Shi Chenxi Dong Zhi Wang Xinxia Tian Song Zhao Jixiao Wang Chemical Engineering Research Center School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China Tianjin Key Laboratory of Membrane Science and Desalination Technology State Key Laboratory of Chemical EngineeringCollaborative Innovation Center of Chemical Science and EngineeringTianjin UniversityTianjin 300350China Research Institute of Shannxi Yanchang Petroleum(Group)Co.Ltd. Xi'an 710075China

In this work, the effects of support surface pore structures(including surface pore size, surface pore density and surface porosity) on the performance of thin film composite(TFC) gas separation membrane over a wide pressure range(from 0.3 to 2.0 MPa) were studied. To fulfill it, the polysulfone(PSf) supports with different surface pore structures were prepared. Two kinds of wide-accepted polymeric membrane materials, i.e., polyvinylamine(PVAm) and Pebax 1657 copolymer, were used as skin layer materials. We pointed out for the first time that the support surface average pore size and pore density could affect the chain mobility of polymer of skin layer at the support surface pore entrance, then, can affect the TFC membrane performance. Besides, we also discussed the effects of support on the TFC membrane performance when the feed pressure changes for the first time. This work can provide guidance for choosing a suitable support for TFC gas separation membrane.

关键词： Support surface pore structures thin film composite gas separation membrane Polymer mobility

Raman microscopy mapping for the purity assessment of chirality enriched carbon nanotube networks in thin- film transistors

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Nano Research 2015年第7期8卷 2179-2187页

作者： Zhao Li Jianfu Ding Paul Finnie Jacques Lefebvre Fuyong Cheng ChristopherT. Kingston Patrick R. L. Malenfant Security and Disruptive Technologies Portfolio National Research Council Canada 1200 Montreal Road Ottawa Ontario K1A OR6 Canada

With recent improvements in carbon nanotube separation methods, the accurate determination of residual metallic carbon nanotubes in a purified nanotube sample is important, particularly for those interested in using semiconducting single-walled carbon nanotubes （SWCNTs） in electronic device applications such as thin-film transistors （TFTs）. This work demonstrates that Raman microscopy mapping is a powerful characterization tool for quantifying residual metallic carbon nanotubes present in highly enriched semiconducting nanotube networks. Raman mapping correlates well with absorption spectroscopy, yet it provides greater differentiation in purity. Electrical data from TFTs with channel lengths of 2.5 and 5μ m demonstrate the utility of the method. By comparing samples with nominal purities of 99.0% and 99.8%, a clear differentiation can be made when evaluating the current on/off ratio as a function of channel length, and thus the Raman mapping method provides a means to guide device fabrication by correlating SWCNT network density and purity with TFT channel scaling.

关键词： raman spectroscopy carbon nanotubes thin film transistors microscopy mapping purity assessment

Modulation of the electronic states of perovskite SrCrO3 thin films through protonation via low-energy hydrogen plasma implantation approaches

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Frontiers of physics 2020年第1期15卷 43-50页

作者： Meng Wu Shanquan Chen Chuanwei Huang Xing Ye Haiping Zhou Xiaochun Huang Kelvin H.L.Zhang Wensheng Yan Lihua Zhang Kisslinger Kim Yingge Du Scott Chambers Jin-Cheng Zheng Hui-Qiong Wang Fujian Provincial Key Laboratory of Semiconductors and Applications Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient DevicesDepartment of PhysicsXiamen UniversityXiamen 361005China Shenzhen Key Laboratory of Special Functional Materials College of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China Center for Functional Nanomaterials Brookhaven National LaboratoryUptonNY 11973-5000USA Physical Sciences Division Physical and Computational Sciences DirectoratePacific Northwest National LaboratoryRichlandWA 99352USA

Hydrogenation of transition metal oxides offers a powerful platform to tailor physical functionalities as well as for potential applications in modern electronic technologies.An ideal nondestructive and efficient hydrogen incorporation approach is important for the realistic technological applications.We demonstrate the proton injection on SrCro3 thin films via an efficient low-energy hydrogen plasma implantation experiments,without destroying the original lattice framework.Hydrogen ions accumu-late largely at the interfacial regions with amorphous character which extend about one-third of the total thickness.The Hx.SrCro3(HSCO)thin films appear like exfoliated layers which however retain the fully strained state with distorted perovskite structure.Proton doping induces the change of Cr oxidation state from Cr^4+to Cr^3+in HSCO thin films and a transition from metallic to insulat-ing phase.Our investigations suggest an attractive platform in manipulating the electronic phases in proton-based approaches and may offer a potential peeling off strategy for nanoscale devices through low-energy hydrogen plasma implantation approaches.

关键词： transition metal oxide thin film metal-insulator transition hydrogenation

Electrochemical corrosion behavior of 2A02 Al alloy under an accelerated simulation marine atmospheric environment

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Journal of Materials Science & Technology 2019年第4期35卷 651-659页

作者： Min Cao Li Liu Zhongfen Yu Lei Fan Ying Li Fuhui Wang Institute of Metal Research Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory for Anisotropy and Texture of Materials (MoE) School of Materials Science and EngineeringNortheastern University

The corrosion behavior of 2 A02 Al alloy under simulated marine atmospheric environment has been studied using mass-gain, scanning electron microscope/energy dispersive spectroscopy(SEM/EDS), laser scanning confocal microscopy, X-ray diffraction spectroscopy and localized electrochemical methods. The results demonstrate that the relationship between the corrosion induced mass-gain and the corrosion time is in accordance with the power rule. The mass-gain increases gradually during the corrosion time,while the corrosion rate decreases. With ongoing of the corrosion, corrosion products film changed from a porous to a compact structure. The various spectroscopic data show that the corrosion products films composed mainly of Al(OH)_3, Al_2O_3 and AlCl_3. The electrochemical corrosion behavior of the 2 A02 Al alloy was studied by electrochemical impedance spectroscopy(EIS).

关键词： thin electrolyte layers Atmospheric corrosion 2A02 Al alloy EIS

Size effect in plastically deformed passivated thin films

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Science China(Physics,Mechanics & Astronomy) 2009年第9期52卷 1375-1381页

作者： HWANG Keh-Chih AML Department of Engineering Mechanics Tsinghua University

The flow theory of mechanism-based strain gradient plasticity theory (MSG) developed by Qiu et al. (2003) is extended for incompressible material. The MSG flow theory is used to predict the increase of plastic work hardening for plane strain tension of surface-passivated Cu thin film. The theoretical predictions agree well with experiments for suitably chosen material parameters.

关键词： MSG theory strain gradient plasticity passivation thin film plain strain tension

Nonlinear primary resonance analysis for a coupled thermo-piezoelectric-mechanical model of piezoelectric rectangular thin plates

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Applied Mathematics and Mechanics(English Edition) 2019年第8期40卷 1155-1168页

作者： Xun WANG Chunxia XUE Haitao LI Department of Mechanics School of ScienceNorth University of China Taiyuan 030051China Shanghai Institute of Applied Mathematics and Mechanics Shanghai UniversityShanghai 200072China

A model of piezoelectric rectangular thin plates with the consideration of the coupled thermo-piezoelectric-mechanical effect is established. Based on the von Kar- man large deflection theory, the nonlinear vibration governing equation is obtained by using Hamilton’s principle and the Rayleigh-Ritz method. The harmonic balance method (HBM) is used to analyze the first-order approximate response and obtain the frequency response function. The system shows non-linear phenomena such as hardening nonlinear- ity, multiple coexistence solutions, and jumps. The effects of the temperature difference, the damping coefficient, the plate thickness, the excited charge, and the mode on the pri- mary resonance response are theoretically analyzed. With the increase in the temperature difference, the corresponding frequency jumping increases, while the resonant amplitude decreases gradually. Finally, numerical verifications are carried out by the Runge-Kutta method, and the results agree very well with the theoretical results.

关键词： piezoelectric rectangular thin plate thermo-piezoelectric-mechanical coupling harmonic balance method (HBM) primary resonance analysis

thin films as an emerging platform for drug delivery

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Asian Journal of Pharmaceutical Sciences 2016年第5期11卷 559-574页

作者： Sandeep Karki Hyeongmin Kim Seon-Jeong Na Dohyun Shin Kanghee Joa Jaehwi Lee Pharmaceutical Formulation Design Laboratory College of PharmacyChung-Ang UniversitySeoul 06974Republic of Korea Bio-Integration Research Center for Nutra-Pharmaceutical Epigenetics Chung-Ang UniversitySeoul 06974Republic of Korea Center for Metareceptome Research Chung-Ang UniversitySeoul 06974Republic of Korea

Pharmaceutical scientists throughout the world are trying to explore thin films as a novel drug delivery tool. thin films have been identified as an alternative approach to conventional dosage forms. The thin films are considered to be convenient to swallow, selfadministrable, and fast dissolving dosage form, all of which make it as a versatile platform for drug delivery. This delivery system has been used for both systemic and local action via several routes such as oral, buccal, sublingual, ocular, and transdermal routes. The design of efficient thin films requires a comprehensive knowledge of the pharmacological and pharmaceutical properties of drugs and polymers along with an appropriate selection of manufacturing processes. Therefore, the aim of this review is to provide an overview of the critical factors affecting the formulation of thin films, including the physico-chemical properties of polymers and drugs, anatomical and physiological constraints, as well as the characterization methods and quality specifications to circumvent the difficulties associated with formulation design. It also highlights the recent trends and perspectives to develop thin film products by various companies.

关键词： thin film Film-forming polymer Mechanical properties Manufacturing Characterization

Investigation on the interface damage in drilling low-stiffness CFRP/Ti stacks

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Chinese Journal of Aeronautics 2019年第9期32卷 2211-2221页

作者： Bin LUO Kaifu ZHANG Shunuan LIU Hui CHENG Runxiao WANG School of Mechanical Engineering Northwestern Polytechnical University

Carbon fiber reinforced plastic and titanium alloy(CFRP/Ti) stacks have been widely used as aerospace structures because of their excellent combination of physical properties. Interface damage caused by interface gaps, significantly different from that of metal/metal stacks, is a common problem in the through-hole drilling of CFRP/Ti stacks with low stiffness. In this study, a force–deformation coupling model was developed to further examine the formation mechanism and the control method of interface damage. Firstly, the coupling model was built considering the interaction between the thrust force and the deformation. To solve this model, a numerical method was proposed in which specific cutting coefficients were calibrated using only the thrust force of rigid stacks. Secondly, drilling experiments were performed with different feed rates and bending stiffness. Experimental results indicate that interface damage mainly includes interlayer chips and surface damage of CFRP layers. The surface damage, which is irreparable, is caused by the rotary extension of metal chips along the interlayer gap. Thirdly, variations of the interface gap were calculated with the coupling model that had been verified by measured thrust forces. The damage area was found to have a linear dependence relation with the interlayer gap. However, in conditions of large gap sizes, the interface damage areas increased with the interlayer gap at high feed rates, while decreasing slightly at low feed rates. This phenomenon was satisfactorily explained by the presented model. Finally, a method was proposed to determine the appropriate pressure exceeding which no interlayer damage will occur. Additional drilling experiments proved the method effective. This study leads to further understanding of the forming mechanism of interlayer damage and of selecting appropriate parameters in drilling low-stiffness composite/metal stacks.

关键词： Coupling effects Drilling Interface damage Interlayer gap thin walled structures

Novel thin plate element theory based on a continuity re-relaxed technique

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Science China(Technological Sciences) 2010年第9期53卷 2450-2457页

作者： CUI XiangYang,LI GuangYao & ZHENG Gang State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,Hunan University,Changsha 410082,China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha China

thin plate problem has been receiving much interest due to its wide application in engineering.In this paper,a novel thin plate element theory is proposed based on a continuity re-relaxed technique to avoid the high continuity requirement for thin plate formulation which needs the high computation cost.The problem is first discretized into a set of background cells with field nodes,and only deflection field is treated as the field variable.On top of the background cells,the integration domains are further formed.The curvatures over integration domains are restructured through the divergence theorem,and the continuity requirement of the trial deflection function for thin plate problems can be re-relaxed.The Galerkin weak form is then used to create the discretized system equations.The curvatures in the integration domains are constant,and the stiffness matrix of the system can be computed directly without numerical integration.The rotational essential boundary conditions are imposed in the process of curvature field construction.Some numerical examples are computed using the RPIM approximation function.The excellent results demonstrate the efficiency of the proposed method.

关键词： thin plate problem continuity re-relaxed curvature field restructured Galerkin weak form