Thermal Conductivity Measurements of Semitransparent Single-Walled Carbon Nanotube Films by a Bolometric Technique

We introduce a new technique for measurement of the thermal conductivity of ultrathin films of single-walled carbon nanotubes (SWNTs) utilizing IR radiation as heat source and the SWNT film as thermometer. The technique is applied to study the temperature dependence of the thermal conductivity of an as-prepared SWNT film obtained in the electric arc discharge process and a film of purified SWNTs prepared by vacuum filtration. The interplay between thermal and electrical transport in SWNT networks is analyzed in relation to the type of intertube junctions and the possibility of optimizing the thermal and electrical properties of SWNT networks for specific applications is discussed

Biologically Inspired Highly Durable Iron Phthalocyanine Catalysts for Oxygen Reduction Reaction in Polymer Electrolyte Membrane Fuel Cells

In the present work, we have designed and synthesized a new highly durable iron phtalocyanine based nonprecious oxygen reduction reaction (ORR) catalyst (Fe-SPc) for polymer electrolyte membrane fuel cells (PEMFCs). The Fe-SPc, with a novel structure inspired by that of naturally occurring oxygen activation catalysts, is prepared by a nonpyrolyzing method, allowing adequate control of the atomic structure and surface properties of the material. Significantly improved ORR stability of the Fe-SPc is observed compared with the commercial Fe-Pc catalysts. The Fe-SPc has similar activity to that of the commercial Fe-Pc initially, while the Fe-SPc displays 4.6 times higher current density than that of the commercial Fe-Pc after 10 sweep potential cycles, and a current density that is 7.4 times higher after 100 cycles. This has been attributed to the incorporation of electron-donating functional groups, along with a high degree of steric hindrance maintaining active site isolation. Nonprecious Fe-SPc is promising as a potential alternative ORR electrocatalyst for PEMFCs

Thin Film Polyamide Nanocomposite Membrane Decorated by Polyphenol-Assisted Ti₃C₂T_<i>x</i> MXene Nanosheets for Reverse Osmosis

Transition-metal carbides (MXenes), multifunctional 2D materials, have caught the interest of researchers in the fabrication of high-performance nanocomposite membranes. However, several issues regarding MXenes still remain unresolved, including low ambient stability; facile restacking and agglomeration; and poor compatibility and processability. To address the aforementioned challenges, we proposed a facile, green, and cost-efficient approach for coating a stable layer of plant-derived polyphenol tannic acid (TA) on the surface of MXene (Ti3C2Tx) nanosheets. Then, high-performance reverse osmosis polyamide thin film nanocomposite (RO-PA-TFN) membranes were fabricated by the incorporation of modified MXene (Ti3C2Tx–TA) nanosheets in the polyamide selective layer through interfacial polymerization. The strong negative charge and hydrophilic multifunctional properties of TA not only boosted the chemical compatibility between Ti3C2Tx MXene nanosheets and the polyamide matrix to overcome the formation of nonselective voids but also generated a tight network with selective interfacial pathways for efficient monovalent salt rejection and water permeation. In comparison to the neat thin film composite membrane, the optimum TFN (Ti3C2Tx–TA) membrane with a loading of 0.008 wt % nanofiller revealed a 1.4-fold enhancement in water permeability, a well-maintained high NaCl rejection rate of 96% in a dead-end process, and enhanced anti-fouling tendency. This research offers a facile way for the development of modified MXene nanosheets to be successfully integrated into the polyamide-selective layer to improve the performance and fouling resistance of TFN membranes

Effect of electrode physical and chemical properties on lithium-ion battery performance

The effect of physical and chemical properties on the performance of both positive and negative electrodes is studied for lithium-ion (Li-ion) batteries. These properties include the lithium diffusivity in the active electrode material, the electrical conductivity of the electrode, and the reaction rate constant at electrode active sites. The specific energy and power of the cells are determined at various discharge rates for electrodes with different properties. In addition, this study is conducted across various cell design cases. The results reveal that at moderate discharge rates, lithium diffusivity in the active negative-electrode material has the highest impact on cell performance. The specific energy and power of the cell are improved ~11% by increasing the lithium diffusivity in the active negative-electrode material by one order of magnitude. Around 4% improvement in the cell performance is achieved by increasing the reaction rate constant at the active sites of either electrodes by one order of magnitude.</p

Development of π–π Interaction-Induced Functionalized Graphene Oxide on Mechanical and Anticorrosive Properties of Reinforced Polyurethane Composites

In this study, three types of amine-functionalized graphene oxide (f-GO) have been synthesized and their polyurethane (PU) composites have been fabricated. Mechanical properties and the anticorrosion performance of as-prepared composites were thoroughly investigated. The amine groups (two aliphatic groups and one aromatic group) on GO influenced the dispersion of the fillers and the properties of the composites. Among the f-GO series, GO functionalized with 2-naphthyl amine (2NA-GO) indicated higher mechanical properties and corrosion resistance than other PU composites. Specifically, the incorporation of 0.5 wt % of 2NA-GO in the PU matrix showed a 2.2 times higher tensile modulus than the neat PU and the highest protection efficiency of 99.94%. This synergetic effect of 2NA-GO was due to the aromatic structure and relatively low molecular weight of 2NA. The aromatic structure developed π–π interfacial interactions between the amine group and phenyl groups of the hard segments in the PU backbone. Furthermore, the lower molecular weight contributed to the uniform dispersion of the filler. Based on the results, molecular structure and molecular weight could be a critical factor in designing the f-GO to improve the mechanical and corrosion properties of PU composites. Additionally, this fact can be contributed to PU industries, which require a high anticorrosion performance as well as enhanced mechanical properties

Reduced Graphene Oxide/Tin–Antimony Nanocomposites as Anode Materials for Advanced Sodium-Ion Batteries

Reduced graphene oxides loaded with tin–antimony alloy (RGO-SnSb) nanocomposites were synthesized through a hydrothermal reaction and the subsequent thermal reduction treatments. Transmission electron microscope images confirm that SnSb nanoparticles with an average size of about 20–30 nm are uniformly dispersed on the RGO surfaces. When they were used as anodes for rechargeable sodium (Na)-ion batteries, these as-synthesized RGO-SnSb nanocomposite anodes delivered a high initial reversible capacity of 407 mAh g^–1, stable cyclic retention for more than 80 cycles and excellent cycle stability at ultra high charge/discharge rates up to 30C. The significantly improved performance of the synthesized RGO-SnSb nanocomposites as Na-ion battery anodes can be attributed to the synergetic effects of RGO–based flexible framework and the nanoscale dimension of the SnSb alloy particles (<30 nm). Nanosized intermetallic SnSb compounds can exhibit improved structural stability and conductivity during charge and discharge reactions compared to the corresponding individuals (Sn and Sb particles). In the meantime, RGO sheets can tightly anchor SnSb alloy particles on the surfaces, which can not only effectively suppress the agglomeration of SnSb particles but also maintain excellent electronic conduction. Furthermore, the mechanical flexibility of the RGO phase can accommodate the volume expansion and contraction of SnSb particles during the prolonged cycling, therefore, improve the electrode integrity mechanically and electronically. All of these contribute to the electrochemical performance improvements of the RGO-SnSb nanocomposite-based electrodes in rechargeable Na-ion batteries

Facile Synthesis and Evaluation of Nanofibrous Iron–Carbon Based Non-Precious Oxygen Reduction Reaction Catalysts for Li–O₂ Battery Applications

Development of low cost active catalysts toward oxygen reduction reaction (ORR) is critical for the effective operation of Li–O₂ battery. Porous nonprecious iron–carbon based nanofiber catalysts have been developed by electrospinning method. The catalysts demonstrated similar ORR catalytic activity for ORR as the commercial Pt-based catalysts in the aqueous half-cell voltammetry sweeps. In the Li–O₂ aprotic environment, the catalyst exhibited higher on-set potentials when compared to glassy carbon and Pt disk electrodes. The results show that the nonprecious electrospun nanofiber could be an effective low cost ORR catalyst at the cathode for Li–O₂ battery

Additional file 1 of The predictive value of baseline symptom score and the peripheral CD4CD8 double-positive T cells in patients with AECOPD

Additional file 1: Table S1. Study cohort characteristics are stratified by systemic glucocorticoids in patients with acute exacerbation of COPD. Table S2. Effects of lymphocyte subsets on systemic glucocorticoids in patients with acute exacerbation of COPD. Table S3. Multivariate analysis for systemic glucocorticoids in patients with acute exacerbation of COPD. Table S4. Study cohort characteristics are stratified by noninvasive ventilation in patients with acute exacerbation of COPD. Table S5. Effects of lymphocyte subsets on noninvasive ventilation in patients with acute exacerbation of COPD. Table S6. Multivariate analysis for noninvasive ventilation in patients with acute exacerbation of COPD. Table S7. Study cohort characteristics are stratified by frequent exacerbation with a 2-year follow-up. Table S8. Effects of lymphocyte subsets on frequent exacerbation with a 2-year follow-up. Table S9. Multivariate analysis for frequent exacerbation with a 2-year follow-up. Table S10. An unadjusted cox regression model including study cohort characteristics to predict the time to hospital re‑admission. Table S11. An unadjusted Cox regression model including lymphocyte subsets to predict the time to hospital re‑admission. Table S12. Adjusted cox regression model to predict the time to hospital re‑admissio

Additional file 1: of Microarray analysis of long non-coding RNA expression profiles in monocytic myeloid-derived suppressor cells in Echinococcus granulosus-infected mice

Table S1. Primers used in qPCR detection of selected lncRNAs. (XLSX 10 kb

Highly Active and Durable Core–Corona Structured Bifunctional Catalyst for Rechargeable Metal–Air Battery Application

A new class of core–corona structured bifunctional catalyst (CCBC) consisting of lanthanum nickelate centers supporting nitrogen-doped carbon nanotubes (NCNT) has been developed for rechargeable metal–air battery application. The nanostructured design of the catalyst allows the core and corona to catalyze the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), respectively. These materials displayed exemplary OER and ORR activity through half-cell testing, comparable to state of the art commercial lanthanum nickelate (LaNiO₃) and carbon-supported platinum (Pt/C), with added bifunctional capabilities allowing metal–air battery rechargeability. LaNiO₃ and Pt/C are currently the most accepted benchmark electrocatalyst materials for the OER and ORR, respectively; thus with comparable activity toward both of these reactions, CCBC are presented as a novel, inexpensive catalyst component for the cathode of rechargeable metal–air batteries. Moreover, after full-range degradation testing (FDT) CCBC retained excellent activity, retaining 3 and 13 times greater ORR and OER current upon comparison to state of the art Pt/C. Zinc–air battery performances of CCBC is in good agreement with the half-cell experiments with this bifunctional electrocatalyst displaying high activity and stability during battery discharge, charge, and cycling processes. Owing to its outstanding performance toward both the OER and ORR, comparable with the highest performing commercial catalysts to date for each of the respective reaction, coupled with high stability and rechargeability, CCBC is presented as a novel class of bifunctional catalyst material that is very applicable to future generation rechargeable metal–air batteries