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Preparation of porous structures on copper microchannel surfaces by laser writing

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Science China(Technological Sciences) 2019年第12期62卷 2261-2270页

作者： DENG DaXiang CHEN XiaoLong CHEN Liang LIAN YunSong FU Ting School of Mechanical Engineering and Automation Harbin Institute of Technology(Shenzhen)Shenzhen 518055China Department of Mechanical&Electrical Engineering Xiamen UniversityXiamen 361005China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and TechnologyWuhan 430081China

A laser writing method is developed to fabricate porous structures on copper microchannel wall surfaces for enhanced microchannel heat sinks(MHSs). The formation feasibility together with its mechanism of such porous structures is explored by the comparison of dry and wet laser writing process, i.e., in both air atmosphere and under de-ionized water. Rectangular microchannels with ripples-like porous structures on the wall surfaces, which consisted of numerous micro-holes and micro-cavities,have been successfully formed in the dry laser writing process. Nevertheless, the microchannel wall surfaces were hardly altered in wet conditions. Besides, the effect of laser fluence on the formation of porous structures on the microchannels was also assessed in both dry and wet conditions. In dry laser writing process, the microchannel depth and surface roughness of wall surface increased monotonically, whereas the microchannel bottom width decreased continuously with increasing the laser fluence. On the other hand, the microchannel wall kept almost unchanged with smooth surfaces with increasing laser fluence in wet conditions.

关键词： laser writing porous surface microchannel heat sinks surface morphology

Vacuum wetting of Ag/TA2 to develop a novel micron porous Ti with significant biocompatibility and antibacterial activity

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Journal of Materials Science & Technology 2022年第21期116卷 180-191页

作者： Guanpeng Liu Yulong Li Ming Yan Jicai Feng Jian Cao Min Lei Quanwen Liu Xiaowu Hu Wenqin Wang Xuewen Li Key Lab for Robot and Welding Automation of Jiangxi Province Mechanical and Electrical Engineering SchoolNanchang UniversityNanchang 330031China Jiangxi Provincial Key Laboratory of Interdisciplinary Science Nanchang UniversityNanchang 330031China Department of Materials Science and Engineering and Shenzhen Key Laboratory for Additive Manufacturing of High-Performance Materials Southern University of Science and TechnologyShenzhen 518055China State Key Lab of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China The National Engineering Research Center for Bioengineering Drugs and the Technologies Institute of Translational MedicineNanchang UniversityNanchang 330031China The Engineering Training Center of Nanchang University Mechanical and Electrical Engineering SchoolNanchang UniversityNanchang 330031China

porous Ti with low modulus,excellent bio-corrosion resistance,biocompatibility,and antibacterial activity is highly pursued as advanced implant *** this work,a new approach to prepare micron porous structures on the surface layer of a grade 2 commercially-pure Ti(TA2)was proposed,which utilized a simple vacuum wetting process of pure Ag on the surface of *** microstructure,corrosion resistance,biocompatibility,mechanical properties,antibacterial ability,and formation mechanism of the asfabricated porous Ti were *** results show that the pores(with average pore sizes of 0.5-5μm)are distributed on the surface layer of the TA2 with a depth of~10μ*** particular,a large number of silver nanoparticles(Ag NPs)form which are dispersed on the porous *** formation mechanisms of the porous structures and Ag NPs were elucidated,suggesting that the volatilization/sublimation of Ag in TA2 is *** porous Ti possesses excellent bio-corrosion resistance,surface wettability,biocompatibility,antibacterial activity,and a relatively low elastic modulus of 40-55 GPa,which may have a promising future in the field of orthopedic *** work also provides a novel idea for the development of advanced porous Ti materials for orthopedic-related basic research and biomedical applications.

关键词： porous titanium Biomaterials Vacuum wetting porous surface Antibacterial activity

Simultaneous Evaporation and Foaming for Batch Coaxial Extrusion of Liquid Metal/Polydimethylsiloxane porous Fibrous TENG

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Advanced Fiber Materials 2023年第6期5卷 1949-1962页

作者： Xinghao Zhang Jiawen Xu Xiaomei Zhang Guojie Chao Qixin Cao Tianxi Liu Yu Liu Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment School of Mechanical EngineeringJiangnan UniversityWuxi 214122People’s Republic of China Key Laboratory of Synthetic and Biological Colloids Ministry of Education School of Chemical and Material EngineeringJiangnan UniversityWuxi 214122People’s Republic of China

The utilization of textile-based triboelectric nanogenerators(t-TENGs)offers great potential for providing sustainable and wearable ***,the current designs of t-TENGs present limitations in terms of low electrical outputs and less developed,straightforward batch processing ***,a facile bottom-up foaming-combined coaxial extrusion method is developed for the massive fabrication of liquid metal/polydimethylsiloxane(PDMS)core–shell porous fibrous TENG,which can be directly woven to form *** designs are studied for high-fidelity fibrous TENG manufacturing and porosity-controlled micropore ***,porous fibrous TENGs are applied to integrate different woven structures,and the electrical and mechanical performances of the t-TENGs are *** with plain surface fibrous TENG,the porous fibrous TENG achieves a~fivefold improvement in the open-circuit voltage(V_(OC))and a~sevenfold improvement in the short-circuit current(I_(SC)).These outcomes indicate that we can prepare a range of polymers for t-TENGs with enhanced output performance even though they do not demonstrate great *** work also demonstrates successful integration for sustainably powering miniature *** results can contribute to human motion energy harvesting for wearable self-powered sensors.

关键词： Triboelectric nanogenerators Coaxial fibers porous surface Self-powered sensors

Synthesis and electrocatalytic activity of Au@Pd coreshell nanothorns for the oxygen reduction reaction

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Nano Research 2014年第8期7卷 1205-1214页

作者： Gengtao Fu Zhenyuan Liu Yu Chen Jun Lin Yawen Tang Tianhong Lu School of Materials Science and Engineering Shaanxi Normal University Xi'an 710062 China Jiangsu Key Laboratory of New Power Batteries Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials School of Chemistry and Materials Science Nanjing Normal University Nanjing 210023 China

Bimetallic core-shell nanostructures with porous surfaces have drawn considerable attention due to their promising applications in various fields, including catalysis and electronics. In this work, Au@Pd core-shell nanothorns （CSNTs） with rough and porous surfaces were synthesized for the first time through a facile co-chemical reduction method in the presence of polyallylamine hydrochloride （PAH） and ethylene glycol （EG） at room temperature. The size, morphology, and composition of Au@Pd CSNTs were investigated by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, energy dispersive spec- troscopy （EDX）, EDX mapping, and X-ray photoelectron spectroscopy （XPS）. The electrochemical properties of as-synthesized Au@Pd CSNTs were also studied by various electrochemical techniques. Au@Pd CSNTs exhibited remarkably high electrocatalytic activity and durability for the oxygen reduction reaction （ORR） in the alkaline media, owing to the unique porous structure and the synergistic effect between the Au core and Pd shell.

关键词： gold palladium porous surface core-shell structure oxygen reduction reaction

Influence of Brownian Motion, Thermophoresis and Magnetic Effects on a Fluid Containing Nanoparticles Flowing over a Stretchable Cylinder

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Fluid Dynamics & Materials Processing 2024年第3期20卷 525-536页

作者： Aaqib Majeed Ahmad Zeeshan Department of Mathematics The University of FaisalabadFaisalabad38000Pakistan Department of Mathematics and Statistics FBASInternational Islamic University IslamabadIslamabad44000Pakistan

The influence of Brownian motion and thermophoresis on a fluid containing nanoparticles flowing over a stretchable cylinder is *** classical Navier-Stokes equations are considered in a porous *** addition,the Lorentz force is taken into *** controlling coupled nonlinear partial differential equations are transformed into a system of first order ordinary differential equations by means of a similarity *** resulting system of equations is solved by employing a shooting approach properly implemented in *** evolution of the boundary layer and the growing velocity is shown graphically together with the related profiles of concentration and *** magnetic field has a different influence(in terms of trends)on velocity and concentration.

关键词： Mixed convection Brownian motion heat transfer porous surface velocity slip

Micro-configuration Observation of porous Bioceramic for Sliding on Intestinal Mucus Film

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Journal of Wuhan University of Technology(Materials Science) 2005年第B12期20卷 210-213页

作者：王欣宇 Biomedical Materials and Engineering Research Center Wuhan University of Technology Wuhan 430070 China

The microstructure of the prepared porous bioceramic material, including surface porosity and apparent contact area with the artificial mucus film are computed and analyzed. The surface micro-configurations of the porous material before and after sliding on the mucus film are observed in 2 D and 3 D by digital microsco py, We describe how much mucus enters and stays within different pares, and how the porous material with rough/ porous surface contacts with the mucus film （ elastic surfucel gel ） . The presented results illustrate that the material with different porous structure can lead to different mucus suction, surface scraping and changes of contact area and condition during sliding, which will be active for high friction of robotic endoscope with the intestinal wall for intestinal locomotion.

关键词： micro- configuration sliding porous surface

Heat transfer and nanofluid flow over a porous plate with radiation and slip boundary conditions

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Journal of Central South University 2019年第5期26卷 1099-1115页

作者： Hamid MALEKI Jalal ALSARRAF Abbas MOGHANIZADEH Hassan HAJABDOLLAHI Mohammad Reza SAFAEI Department of Mechanical Engineering Isfahan University of TechnologyIsfahan 84156-83111Iran Department of Automotive and Marine Engineering Technology College of Technological StudiesThe Public Authority for Applied Education and TrainingKuwait Biomaterial Research Group Department of Materials EngineeringIsfahan University of TechnologyIsfahan 84156-83111Iran Department of Mechanical Engineering Vali-e-Asr University of RafsanjanRafsanjanIran Division of Computational Physics Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Electrical and Electronics Engineering Ton Duc Thang UniversityHo Chi Minh CityVietnam

Presence of different terms with various values can alter the thermal behavior of the nanofluids flow over porous *** aim of this research is to study the influence of nanoparticles volume fraction,nanoparticles type,suction or injection,the heat generation or absorption,the Eckert number,thermal and velocity slip parameters,and radiation on the velocity and temperature fields on the flow and heat transfer over a porous flat *** different types of nanoparticles including metal nanoparticles (Cu),metal oxide nanoparticles (Al2O3) and carbon-based nanomaterials (MWCNTs and SWCNTs) which were dispersed in the water (as based fluid) are *** governing equations are converted into the ordinary differential equations using similarity solution and solved numerically by the RKF45 *** results of the simulations showed a contradiction with the results of other researchers who expressed that using nanoparticles with higher thermal conductivity and volume fraction led to increasing heat transfer rate in nanofluids;this study proves that,in some cases,boosting the volume fraction of nanoparticles has a potential to decrease the heat transfer rate due to significant changes in values of some parameters including radiation,heat generation,and viscous dissipation.

关键词： radiation slip condition porous surface heat generation/absorption viscous dissipation nanofluid

Enhanced Pool Boiling Heat Transfer on Copper Foam Welded surfaces

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Transactions of Nanjing University of Aeronautics and Astronautics 2022年第S01期39卷 32-41页

作者： HU Zhuoyang CUI Enhua KHAN Muhammad Niaz ZHANG Qian CHEN Xuefeng JI Keju College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China

Enhanced pool boiling heat transfer of the porous structure is critical to the thermal management *** this paper,pool boiling heat transfer experiments are performed on copper foam welded surfaces in de-ionized water to investigate the effects of basic parameters of copper foam on heat transfer *** phenomenon is observed to facilitate the understanding of enhancement *** results show that copper foam welded surfaces can significantly enhance the pool boiling heat transfer performance,reduce the boiling incipience temperature by 7-9℃,and reach two times heat transfer coefficient compared with smooth plain surfaces due to numerous nucleation sites,extended surface areas,and enhanced turbulent *** density and thickness of foam have two side effects on heat transfer.

关键词： copper foam porous surface enhanced heat transfer pool boiling