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Fabrication of patterned graphitized carbon wires using low voltage near-field electrospinning, pyrolysis, electrodeposition, and chemical vapor deposition

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Microsystems & Nanoengineering 2020年第1期6卷 1341-1352页

作者： Derosh George Adrian Garcia quang Pham Mario Ramos Perez Jufeng Deng Michelle trang nguyen tuo Zhou Sergio OMartinez-Chapa Yoonjin Won Chong Liu Roger CLo Regina Ragan Marc Madou Mechanical and Aerospace Engineering University of CaliforniaIrvineUSA Chemical Engineering and Materials Science University of CaliforniaIrvineUSA Materials and Manufacturing technology University of CaliforniaIrvineUSA School of Engineering and Sciences Tecnologico de MonterreyMonterreyMexico Mechanical Engineering Dalian University of TechnologyDalianChina Chemical Engineering California State UniversityLong BeachUSA Present address:Mechanical Engineering Centro de Ensenanza Tecnica y Superior UniversidadMexicaliMexico

We herein report a high-resolution nanopatterning method using low voltage electromechanical spinning with a rotating collector to obtain aligned graphitized micro and nanowires for carbon nanomanufacturing.A small wire diameter and a small inter-wire spacing were obtained by controlling the electric field,the spinneret-to-collector distance,the pyrolysis parameters,the linear speed of the spinneret,the rotational speed of the *** a simple scaling analysis,we show how the straightness and the diameter of the wires can be controlled by the electric field and the distance of the spinneret to the collector.A small inter-wire spacing,as predicted by a simple model,was achieved by simultaneously controlling the linear speed of the spinneret and the rotational speed of the *** drying of the polymer nanowires enabled the facile fabrication of suspended wires over various *** polyacrylonitrile wires were carbonized using standard stabilization and pyrolysis to obtain carbon *** carbon nanowires with a diameter oftablished a method for making patterned,highly graphitized structures by using the aforementioned carbon wire structures as a template for chemical vapor deposition of *** patterning technique offers high throughput for nano writing,which outperforms other existing nanopatterning techniques,making it a potential candidate for large-scale carbon nanomanufacturing.

关键词： nanowires carbon field

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Unusual switchable peroxidase-mimicking nanozyme for the determination of proteolytic biomarker

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Nano Research 2019年第3期12卷 509-516页

作者： Claire McVey Natasha Logan nguyen t. K. thanh Christopher Elliott Cuong Cao Institute for Global Food Security School of Biological Sciences Queens University Belfast 18-30 Malone Road Belfast BT9 5BN UK Biophysics Group Department of Physics and Astronomy University College London London WC1E 6BT UK UCL Healthcare Biomagnetic and Nanomaterials Laboratories 21 Albemarle Street London W1S 4BS UK Material and Advanced technologies for Healthcare Queens University Belfast 18-30 Malone Road Belfast BT9 5BN UK

Detection of enzyme biomarkers originating from either bio-fluids or contaminating microorganisms is of utmost importance in clinical diagnostics and food safety. Herein, we present a simple, low-cost and easy-to-use sensing approach based on the switchable peroxidase-mimicking activity of plasmonic gold nanoparticles (AuNPs) that can catalyse for the oxidation of 3,3’,5’5-tetramethylbenzidine (tMB) for the determination of protease enzyme. the AuNP surface is modified with casein, showing dual functionalities. the first function of the coating molecule is to suppress the intrinsic peroxidase-mimicking activity of AuNPs by up to 77.1%, due to surface shielding effects. Secondly, casein also functions as recognition sites for the enzyme biomarker. In the presence of protease, the enzyme binds to and catalyses the degradation of the coating layer on the AuNP surface, resulting in the recovery of peroxidase-mimicking activity. this is shown visually in the development of a blue colored product (oxidised tMB) or spectroscopically as an increase in absorbance at 370 and 650 nm. this mechanism allows for the detection of protease at 44 ng·mL^-1 in 90 min. the nanosensor circumvents issues associated with current methods of detection in terms of ease of use, compatibility with point-of-care testing, low-cost production and short analysis time. the sensing approach has also been applied for the detection of protease spiked in ultra-heat treated (UHt) milk and synthetic human urine samples at a limit of detection of 490 and 176 ng·mL^-1, respectively, showing great potential in clinical diagnostics, food safety and quality control.

关键词： gold nano particles peroxidase-mimicking nanozyme enzyme detection biomarkers

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Interactions between metal ions and the biopolymer in activated sludge： quantification and effects of system pH value

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Frontiers of Environmental Science & Engineering 2017年第1期11卷 79-87页

作者： Yun Zhou Siqing Xia Binh t. nguyen Min Long Jiao Zhang Zhiqiang Zhang State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and Engineering Tongji University Shanghai 200092 China Biodesign Swette Center for Environmental Biotechnology Arizona State University Tempe AZ 85287-5701 USA School of Civil Engineering and transportation Shanghai Urban Construction Vocational College Shanghai 200432 China

the quantification and effects of system pH value on the interactions between Pb（II） and the biopolymer in activated sludge were investigated. the biopolymer had two protein-like fluorescence peaks （Ex/Em = 280 nm1326-338 nm for peak A; Ex/Em = 220-230 nm/324-338 nm for peak B）. the fluorescence intensities of peak B were higher than those of peak A. the fluorophores of both peaks could be largely quenched by Pb（ll）, and the quencher dose for peak B was about half of that for peak A. the modified Stern-Volmer equation well depicted the fluorescence quenching titration. the quenching constant （Ka） values for both peaks decreased with rising system pH value, and then sharply decreased under alkaline conditions. It could be attributed to that the alkaline conditions caused the reduction of available Pb（II） due to the occurrence of Pb（OH）2 sediments. the Ka values of peak B were bigger than those for peak A at the same system pH values. Accordingly, the aromatic proteins （peak B） played a key role in the interactions between metal ions and the biopolymer.

关键词： Metal ions Biopolymer Activated sludge three-dimensional excitation emission matrix (3D-EEM) Fluorescence regional integration (FRI) technique Quantification

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Effect of Meteorological Factors on PM<sub>10</sub>Concentration in Hanoi, Vietnam

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Journal of Geoscience and Environment Protection 2019年第11期7卷 138-150页

作者： nguyen Anh Dung Duong Hong Son nguyen the Duc Hanh Doan quang tri Department of Science and technology Ministry of Natural Resources and Environment Hanoi Vietnam Water Resources Institute Ministry of Natural Resources and Environment Hanoi Vietnam Faculty of Environment Hanoi University of Natural Resources and Environment Ministry of Natural Resources and Environment Hanoi Vietnam Vietnam Journal of Hydrometeorology Viet Nam Meteorological and Hydrological Administration Hanoi Vietnam

According to the Ministry of Natural Resources and Environment, Hanoi city is currently facing the increased air pollution, especially particulate matter. this study examines the influence of meteorological factors including temperature, humidity and wind speed on PM10 concentration in Hanoi. the data used in this study include 24-h PM10 concentration data, hourly temperature, humidity and wind speed data in 2018 at three automatic air monitoring stations under Vietnam Environment Administration and Hanoi Natural Resources and Environment Department. the SPSS statistical analysis tools are utilized to analyze the correlation between PM10 concentration and meteorological factors through the Spearman (r) correlation coefficient. Additionally, the Independent-Sample t-test is also employed to assess the difference in PM10 concentration in the period between dry season (from October to March) and wet season (from May to September). the results show that there is a trend of seasonal variation of PM10 concentration. Specifically, PM10 concentration recorded a higher value in winter and lower in summer. Different correlations between air pollutants and meteorological factors were also observed. PM10 concentration was inversely correlated (r 10 concentration during dry and wetseason. this outcome has confirmed the important role of meteorological factors in the formation of air pollution with large variations in different seasons and geological areas.

关键词： Meteorology temperature Humidity Wind Speed PM10 Air Quality

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Constitutive modeling of ultra?fine?grained titanium flow stress for machining temperature prediction

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Bio-Design and Manufacturing 2019年第3期2卷 153-160页

作者： Jinqiang Ning Vinh nguyen Yong Huang Karl t.Hartwig Steven Y.Liang George W.Woodruff School of Mechanical Engineering Georgia Institute of Technology801 Ferst DriveAtlantaGA 30332USA Department of Mechanical and Aerospace Engineering University of Florida231 MAE-AP.O.Box 116250GainesvilleFL 32611USA Department of Mechanical Engineering Texas A&M University3123 TAMUCollege StationTX 77843?3123USA

this work investigates the machining temperatures of ultra-fine-grained titanium(UFG ti),prepared by equal channel angular extrusion,through analytical *** ti has great usefulness in biomedical applications because of its high mechanical strength,sufficient manufacturability,and high *** temperatures were predicted using a physics-based predictive model based on material constitutive relation and mechanics of the orthogonal cutting *** minimization between the stress calculated using Johnson–Cook constitutive model and the same stress calculated using mechanics model yields the estimation of machining temperatures at two deformation *** agreements are observed upon validation to the values reported in the *** machinability of UFG ti is investigated by comparing its machining temperature to that of ti–6Al–4V alloy under the same cutting *** lower temperatures are observed in machining UFG *** computational efficiency of the presented model is investigated by comparing its average computational time(~0.5 s)to that of a widely used modified chip formation model(8900 s)with comparable prediction *** work extends the applicability of the presented temperature model to a broader class of materials,specifically ultra-fine-grained *** high computational efficiency allows the in situ temperature prediction and optimization of temperature condition with process parameters planning.

关键词： Ultra-fine-grained titanium Analytical modeling High computational efficiency Johnson–Cook model Cutting mechanics

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