Enhancement of Oxygen Transfer by Design Nickel Foam Electrode for Zinc−Air Battery

This is the final version of the article. Available from Electrochemical Society via the DOI in this record.To develop a long-lifetime metal-air battery, oxygen reduction electrodes with improved mass-transfer routes are designed by adjusting the mass ratio of the hydrophobic polytetrafluoroethylene (PTFE) to carbon nanotubes (CNTs) in nickel foam. The oxygen reduction catalyst MnO2 is grown on the nickel foam using a hydrothermal method. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis are employed to characterize the morphology, crystal structure, chemical composition, and pore structure of the electrodes, respectively. The air electrodes are evaluated using constant-current tests and electrochemical impedance spectroscopy. A PTFE:CNT mass ratio of 1:4–2:1 with 3-mm-thick nickel foam yields the optimal performance due to the balance of hydrophilicity and hydrophobicity. When the electrodes are applied in primary zinc–air batteries, the electrode with a PTFE:CNT mass ratio of 1:4 achieves the maximum power density of 95.7 mW cm−2 with a discharge voltage of 0.8 V at 100 mA cm−2, and completes stable discharge for over 14400 s at 20 mA cm−2.The authors gratefully acknowledge the financial support provided by the National Natural Science Foundation of China (21276134, 21776154) and the National 863 Project (2012AA051203)

Multichannel wavelength conversion of 40 Gbit/s NRZ DPSK signals in a highly nonlinear dispersion flattened lead silicate fibre

We experimentally demonstrate the wavelength conversion of three wavelength multiplexed 40 Gbit/s Differential Phase Shift Keyed (DPSK) signals in a 2.2m length of highly nonlinear, dispersion tailored W-type lead-silicate optical fibre

A model-based multithreshold method for subgroup identification

Thresholding variable plays a crucial role in subgroup identification for personalizedmedicine. Most existing partitioning methods split the sample basedon one predictor variable. In this paper, we consider setting the splitting rulefrom a combination of multivariate predictors, such as the latent factors, principlecomponents, and weighted sum of predictors. Such a subgrouping methodmay lead to more meaningful partitioning of the population than using a singlevariable. In addition, our method is based on a change point regression modeland thus yields straight forward model-based prediction results. After choosinga particular thresholding variable form, we apply a two-stage multiple changepoint detection method to determine the subgroups and estimate the regressionparameters. We show that our approach can produce two or more subgroupsfrom the multiple change points and identify the true grouping with high probability.In addition, our estimation results enjoy oracle properties. We design asimulation study to compare performances of our proposed and existing methodsand apply them to analyze data sets from a Scleroderma trial and a breastcancer study

A single-mode, high index-contrast, lead silicate glass fibre with high nonlinearity, broadband near-zero dispersion at telecommunication wavelengths

We report on the design, fabrication and characterization of a single-mode W-type lead silicate glass fibre with flattened and near-zero dispersion profile at telecom wavelengths and high nonlinearity of 820 W-1km-1 at 1.55 µm

High volumetric energy density capacitors based on new electrode material lanthanum nitride

This is the author accepted manuscript. The final version is available from the American Chemical Society via the DOI in this recordLaN is synthesized via calcining La2O3 in NH3 and studied as capacitive material for energy storage. A volumetric capacitance of 951.3 F cm-3 was found in 1 mol dm-3 Na2SO4 using a current density of 1 Ag-1, with less than 1% loss of capacitance being experienced after 5000 cycles. In addition, 87.3% of the initial capacitance remained at a current density of 10 A g-1. LaN exhibits high capacitance that is attributed to subsurface space charge accumulation with a possible electric double-layer capacitor component. A reversible electrode process ensures long cycle life and favorable electrical charge transfer. The assembled LaN symmetrical capacitor showed high volumetric energy densities, facilitating high-duty applications.National Natural Science Foundation of ChinaFoundation for Innovation Groups of Basic Research in Gansu Provinc

Multi-functional fluorescent carbon dots with antibacterial and gene delivery properties

Glucose is abundant in nature and can be found in various sources. In this study, we developed multifunctional carbon dots (CDs) with glucose, and poly(ethyleneimine) (PEI) which were further quaternized using a facile approach. The CDs are designed to possess both antibacteria and gene delivery capabilities. The inherent property was characterized with TEM, NMR, FTIR and fluorescent spectroscopy. Antibacterial activity was evaluated with Broth minimum inhibitory concentration (MIC) assay on both gram-positive and gram-negative bacteria. The CDs showed excellent inhibitation to both bacteria. The expression of CDs condensed plasmid DNA in HEK 293T cells was investigated with Luciferase expression assay. Gene transfection capability of the quaternized CDs was found to be up to 104 times efficient than naked DNA delivery

Optical conductivity study of screening of many-body effects in graphene interfaces

Theoretical studies have shown that electron-electron (e-e) and electron-hole (e-h) interactions play important roles in many observed quantum properties of graphene making this an ideal system to study many body effects. In this report we show that spectroscopic ellipsometry can enable us to measure this interactions quantitatively. We present spectroscopic data in two extreme systems of graphene on quartz (GOQ), an insulator, and graphene on copper (GOC), a metal which show that for GOQ, both e-e and e-h interactions dominate while for GOC e-h interactions are screened. The data further enables the estimation of the strength of the many body interaction through the effective fine structure constant, $\alpha_{g}^{*}$. The $\alpha_{g}^{*}$ for GOQ indicates a strong correlation with an almost energy independent value of about 1.37. In contrast, $\alpha_{g}^{*}$ value of GOC is photon energy dependent, is almost two orders of magnitude lower at low energies indicating very weak correlation.Comment: Main Article (4 pages, 4 figures); Supporting Online Material (12 pages, 9 figures

Phase sensitive amplification in a highly nonlinear lead-silicate fibre

We experimentally demonstrate phase-sensitive amplification in a highly nonlinear lead-silicate W-type fibre. A phase-sensitive gain swing of 6dB was observed in a 1.56m sample of the fibre for a total launched power of 33dBm

Flat, broadband supercontinuum generation at low pulse energies in a dispersion-tailored lead-silicate fibre

We report flat, broadband supercontinuum generation at low pump pulse energies (69pJ 740fs pulses at 1540nm) in a lead-silicate fibre providing a unique combination of high nonlinearity (820W-1km-1) and a flat near-zero dispersion profile