查看更多>>摘要：The deposition of droplets inside the deformable surfaces has attracted researchers for decades due to its application in direct-writing microporous polymer architectures, printing embedded flexible wires, patterning functional nanoparticles, etc. Herein, a patterned microstructure method based on droplets, named as the embedded droplet printing (EDP), is proposed. The experiments were conducted at a Weber number of 5.49-17.7 to explore the impact outcome, spreading laws and embedded morphology of the droplets. The rebound of droplets impacting the viscous surface was suppressed under appropriate conditions. The spreading factor of the droplet impacting on the high viscous surface followed the power law d* proportional to t(alpha). However, the exponent a was observed to be in the range 0.042-0.031, much smaller than the reported values (0.1-1), which could be explained by the Oh number. The diameters of droplets wrapped with viscous PDMS were only about 1/6th as compared to the spreading on the surface of PDMS precured for 30 min. In particular, a domain map was plotted in which patterns of solid bracts, plates and coffee rings were printed. Overall, EDP is a promising candidate to tailor the size, depth and morphology of droplets for preparing the patterned microstructures inside the soft materials. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
Kim, YeonsongYang, Ho-SungYoon, JihyunJo, Myeong Jun...
12页
查看更多>>摘要：Porous and heteroatom-doped carbon nanostructures were investigated to address the low specific capacity and poor rate capability of the graphite anode. For successful application to commercial lithium-ion batteries, the electrochemical performances of the porous and heteroatom-doped carbon nanostructures should be evaluated in the full-cell operating voltage window. Herein, polyvinylpyrroli-done (PVP)-derived carbon nanospheres with various morphological and atomic structures were pre-pared by electrospraying and controlled thermal-treatment processes conducted under various thermal oxidation termination temperatures. The carbonaceous microstructures, chemical compositions, and pore structures of the PVP-derived carbon nanospheres were thoroughly examined, while their cycling and rate performances were investigated in the voltage range of 0.01-1.5 V (the normal anode operating range of the full-cell). We identified the ideal carbonaceous anode material conditions, i.e., high carbon and nitrogen content with low oxygen content for high and reversible capacity and rate perfor-mances, and small particle size with low surface area and porosity for long life. Our work demonstrates that optimizing porosity and heteroatom composition is crucial for developing commercially viable car-bonaceous anode materials. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：In reference, the mussel-encouraged surface adhesion chemistry, dopamine oxidative autopolymerization on the surface of halloysite nanotubes (HNTs) was performed to confer hydrophilicity to the HNTs. The additional hydrophilic moieties with surface coating by polydopamine (PDA) was assured with transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) techniques. A PDA/HNT-incorporated polyvinyl alcohol/polyvinyl amine (PVA-PVAm) membrane was fabricated for the pervaporation-dehydration of isopropanol/water (IPA/water), and the filler dispersion, crystallinity, and hydrophilicity of the membrane were confirmed by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and contact angle measurements, respectively. The pervaporation test was performed with membranes having different PDA/HNT contents, where the flux increased from 0.19 to 0.39 kg/m(2)h, and the separation factor decreased from 479 to 63 with the 80/20 (w/w, IPA/water) feed mixture at 40 degrees C. Compared to the unmodified HNT-incorporated membrane, the membrane with 5 wt.% PDA/HNT exhibited superior performance. Upon increasing the feed (85/15 IPA/water w/w) temperature from 40 to 70 degrees C, the flux of water and IPA increased from 0.062 to 0.13 kg/m(2)h and 0.000063 to 0.00144 kg/m(2)h, respectively. The apparent energy of activation calculated using the Arrhenius equation was positive for both IPA and water. The higher energy required for permeation of IPA (99.65 kJ/mol) compared to water (22.69 kJ/mol) is attributed to facile permeation of water compared to IPA through the hydrophilic channel created by PDA-HNT. In long-term operation (120 h), the IPA and water flux of the 5 wt.% PDA/HNT-incorporated PVA-PVAm membrane was maintained using a feed composition of 80/20 (w/w %) IPA/water at 40 degrees C, indicating remarkable reusability of the membrane. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Graphic carbon nitride polymer was modified with transition bimetals compounds by impregnation of pre-prepared g-C3N4 in aqueous solution of ammonium molybdate and vanadate. The prepared hybrid material was characterized by XRD, SEM, TEM, FT-IR, XPS and N-2 adsorption-desorption techniques to determine its surface morphology, composition and structure. The results revealed that VOx-MoOy single molecular layer incorporated into g-C3N4 molecule framework by interaction between host and guest was fabricated. The hybrid composite was employed as catalyst for styrene oxidation to benzaldehyde using molecular oxygen as oxidant. The results indicated that the composite was highly active and selective for styrene oxidation, giving TON 458.8 mol/mol((mo+v)) and 96.7% selectivity to benzaldehyde. The correlation between high activity and surface properties the catalyst was explored. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：FePO4 coated Li5Cr7Ti6O25 nanocomposites are synthesized according to a simple sol-gel method following by a calcination procedure. XRD and Rietveld refinement result indicate that FePO4 decorating does not change the crystal structure and lattice parameters of Li5Cr7Ti6O25. SEM and TEM prove that the particle size of all sample are evenly distributed in the 50-100 nm range. Both energy dispersion spectroscopy mapping and HRTEM indicate the existence of FePO4 on the surface of Li5Cr7Ti6O25, which provides a good conductive contact. CV and EIS exhibit that FePO4 (3 wt%) coated Li5Cr7Ti6O25 material has lower polarization, larger Li+ diffusion coefficient and higher conductivity than other pure Li5Cr7Ti6O25 and other FePO4 coated Li5Cr7Ti6O25 composites. Therefore, FePO4 (3 wt%) coated Li5Cr7Ti6O25 anode material displays the highest charge and discharge capacity at each rate. The enhanced electrochemical performance of FePO4-coated Li5Cr7Ti6O25 result from the enhanced lithium ion and electron transfer kinetics. The pristine Li5Cr7Ti6O25 only shows a specific capacity of similar to 197 mAh g(-1) at 500 mA g(-1) after 100 cycles, but FePO4 (3 wt%)-coated Li5Cr7Ti6O25 achieves a high capacity of similar to 237.9 mAh g(-1). Therefore, the FePO4 coating can be regarded as a promising strategy to improve the electrochemical properties of Li5Cr7Ti6O25. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：A Single-Event MicroKinetic (SEMK) model has been extended towards the simulation of Steady State Isotopic Transient Kinetic Analysis (SSITKA) data for Co catalyzed Fischer-Tropsch Synthesis (FTS). The extended model considers two types of sites and both direct and H-assisted CO dissociation. Regression of the model parameters to the data obtained from 17 steady state and 11 SSITKA experiments resulted in physicochemically meaningful estimates for the activation energies and atomic chemisorption enthalpies. The application of the phenomenological UBI-QEP method allows to physically interpret the nature of the two site types considered in the model, i.e., terrace and step sites. A reaction path analysis shows that over 80 percent of the CO reacts on the step sites. Furthermore, chain growth exclusively occurs on these sites. The terrace sites are less reactive for CO dissociation and are identified as responsible for methane production. A fraction of the alkenes, produced on the step sites, is hydrogenated to alkanes on the terrace sites. Based on model simulations, the metal particle size effect, i.e., a lower TOF, higher methane selectivity and increasing alkane to alkene ratio with decreasing metal particle size, is attributed to an increasing relative importance of the terrace sites on the reaction kinetics. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：Stem cell-based therapeutic approach provides a possible treatment for critical limb ischemia (CLI) by inducing revascularization and regenerating ischemic tissue. However, the clinical benefit is modest due to low cell survival and limited efficacy after transplantation. Cardiac-derived stem cells (CSCs) might be a novel cell source for CLI treatment owing to their superb endothelial differentiation potential and angiogenic paracrine functions. In this study, the angiogenic ability of CSCs was maximized by genetic engineering with constitutively active form of hypoxia-inducible factor-1 alpha (CA-HIF-1 alpha), resistant to oxygen-dependent degradation. CSCs transfected with CA-HIF-1 alpha (CA-HIF-CSCs) promoted supplementary expression of proangiogenic factors including VEGF, bFGF, Ang-1 and PDGF-B, along with enhanced angiogenic function including migratory effect, tube formation and endothelial differentiation potential. In the mouse CLI model, CA-HIF-CSCs transplanted into the ischemic region using fibrin gel as cell delivery vehicle, improved blood perfusion and limb functional recovery with minimal incidence of foot necrosis and limb loss by promoting new vessel formation. Histological evidence further confirmed that CA-HIF-CSC/gel treatment markedly alleviated muscle degeneration and fibrosis. CSCs genetically engineered with constitutively active HIF-1 alpha provide a novel therapeutic modality in CLI combining stem cell and gene therapy. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
Chaemchuen, SomboonChen, ChengHeynderickx, Philippe M.Roy, Soumyajit...
9页
查看更多>>摘要：An efficient and facile approach to synthesize a bi-functional electrocatalyst via combining carbon foam with cobalt-centered zeolitic imidazolate framework (ZIF-67) is reported. The carbon foam was synthesized via dehydration of sugar utilizing zinc nitrate, forming Co3ZnC in the carbon matrix. To obtain Co hybridized and Co particles covered with carbon nanotubes embedded in a carbon matrix (Co-Zn-CNTs), physical mixing of both defines the critical point after pyrolysis. Higher content of N-related species and transition metal species in polyvalent states and well-grown multi-wall carbon nanotubes for charge transfer are achieved after the pyrolysis process. The obtained Co-Zn-CNTs catalyst was employed as cathode and anode for overall water splitting (HER and OER) and showed excellent performances. This development offers a low-cost and straightforward strategy to synthesize catalyst material for large-scale fuel cells and water splitting technologies. This development affords a precise method for effectively improving the electrocatalyst performance derived from the ZIF-67 precursor. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
查看更多>>摘要：In the trends of ever-growing worldwide interest for the environment/health and the corresponding legal regulations, there have been various studies to replace toxic halogenated/aromatic hydrocarbon organic solvents commonly used in the solution-processing of organic semiconductors (OSCs) with more sustainable green solvents. In this paper, we fabricated ambipolar organic thin-film transistors (OTFTs) and complementary-like inverters by blending a p-type OSC (6,13-bis(triisopropylsilylethynyl)pentacene; TIPS-pentacene) and a n-type OSC (N,N'-di-n-octyl-3,4,9,10-perylenetetracarboxylic diimide; PTCDI-C-8) in a single green solvent anisole. In particular, shellac was employed as green dielectric materials and the electrical performance of the resulting devices were compared with those fabricated using toxic solvents or commonly used oxide-based dielectrics. The bulk-heterojunction (BHJ)-structured OTFTs in the optimized condition exhibited typical ambipolar characteristics with relatively balanced charge carrier mobilities as high as 0.042 and 0.14 cm(2) V-1 s(-1) for hole and electron, respectively. Additionally, complementary-like inverters based on the two optimized ambipolar OTFTs showed a decent transfer gain as high as 21 at negative supply voltages of -60 V. Thus, by demonstrating the applicability of green solvents not only for OTFTs but also in the implementation of circuit devices, we expect that the results obtained will spark more interest for the more sustainable fabrication of OSC-based electronic devices and their commercialization/mass-production in the relevant industrial real cases. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
Sayed, Abdelwahed R.Gomha, Sobhi M.Bakir, Esam M.Abd El-Lateef, Hany M....
13页
查看更多>>摘要：Polymer/composite materials have been commonly used as corrosion inhibitors in different fields such as marine, oil field, and engineering industry due to their self-healing and thermal stability features. Herein, novel polythiadiazole, namely poly[(2,6-dicarbonylpyridine)(2,5-dihydrazinyl-1,3,4-thiadiazole)] (AMTP) via the interaction of 2,5-dihydrazinyl-1,3,4-thiadiazole with pyridine-2,6-dicarbonyl dichloride and its composite with alpha-Al(OH)(3-)gel were designed in a good yield. The structures of the fabricated materials are characterized by FT-IR, NMR, SEM, and UV-Vis analyses. The protective action of AMTP and alpha-Al(OH)(3)@AMTP on the C1018-steel corrosion in molar-sulphuric acid was evaluated by potentiodynamicpolarization (PDP) and electrochemical impedance spectroscopic (EIS) methods. PDP findings presented that the AMTP polymer and alpha-Al(OH)(3)@AMTP composite performed as mixed-type inhibitors. The protection capacities of 90.3 and 97.6% were obtained in the presence of optimum dose 100 mg/L of AMTP polymer and alpha-Al(OH)(3)@AMTP composite, respectively. The compound's adsorption on C1018-steel follows the Langmuir isotherm model. The SEM/EDX outcomes reveal that the C1018-steel interface is inhibited by AMTP polymer and alpha-Al(OH)(3)@AMTP composite. DFT calculations exhibited that the efficiency of the prepared materials correlates well with their electron contributing capability, whereas simulations of Monte Carlo exposed that the favorability and extent of adsorption of additive molecules metal interface establish their corrosion protection routines. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.
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