Preparation of anatase TiO2 nanorods from solutions in the absence of surfactants or templates has rarely been reported. The present work has found that hydrothermal treatment of titanate nanotube ...suspensions under an acidic environment resulted in the formation of single-crystalline anatase nanorods with a specific crystal-elongation direction. The nanotube suspensions were prepared by treatment of TiO2 in NaOH, followed by mixing with HNO3 to different pH values. The crystal size of the anatase nanoparticles obtained from the hydrothermal treatment increased with the pH of the suspensions, and nanorods with an aspect ratio up to 6 and a long axis along the anatase 001 were obtained at a pH slightly less than 7. A mechanism for the tube-to-rod transformation has been proposed on the basis of the crystalline structures of the tubes and rods. The local shrinkage of the tube walls to form anatase crystallites and the subsequent oriented attachment of the crystallites have been suggested to be the key steps involved in the nanorod formation.
Electrochemical deposition of p-type Cu2O films on transparent conducting glass from a Cu2SO4 solution was conducted at different temperatures. The films were examined for H2 evolution from ...photoelectrolysis of water under visible light illumination. Using Pt as the counter electrode, photocurrents with corresponding H2 evolution could be observed for the deposited Cu2O films in a Na2SO4 solution under a cathodic bias. The Cu2O films obtained at different deposition temperatures were in the cubic phase, but showed different out-of-plane crystalline orientations. An incident monochromatic photon-to-current conversion efficiency of 26% at 400nm was achieved for a Cu2O film with a 111 out-of-plane orientation, while an efficiency of only 17% was obtained for a film with a 110 orientation. The 111-oriented film exhibited a higher electronic conductivity, which might have led to a higher charge delocalization rate. By coupling with an n-type WO3 film to promote charge transport, the photocurrent for the Cu2O films was significantly improved.
Different p-type Cu2O powders were prepared from electrodeposition and subjected to analysis of their photocatalytic activity in water reduction. The electrodeposited Cu2O powders were obtained by ...scraping the deposited films off the substrate. Under illumination the Cu2O powders alone were not able to catalyze H2 generation from water reduction. However, these Cu2O powders exhibited photocatalytic activity in H2 generation when they were coupled with n-type WO3 in suspensions. The coupling was made to avoid back reactions of the photo-induced charges. The electrodeposited Cu2O powders showed higher photocatalytic activity than a commercially available Cu2O powder. The suspension containing electrodeposited Cu2O with a strong 1 1 1 orientation gave a larger amount of H2 evolution than that containing Cu2O with a 1 1 0 orientation. Appropriate crystalline-texture tuning, as well as charge delocalization promotion, is looked to as the key issue for efficient H2 generation from water reduction over p-type Cu2O photocatalysts.
Copper oxide was deposited on tubular TiO2 via Cu2+ introduction into a titanate nanotube aggregate followed by calcination. The titanate has a layered structure allowing Cu intercalation and can ...readily transform into anatase TiO2 via calcination for condensation of the constituting layers. The activity of the tubular catalysts, with a Cu content of 2 wt %, in selective NO reduction with NH3 was compared with those of other 2 wt % Cu/TiO2 catalysts using TiO2 nanoparticles as the support. The Cu species supported on the nanotubes showed a higher activity than those supported on the nanoparticles. X-ray absorption near-edge structure (XANES) analysis showed that the Cu species on all the TiO2 supports are in the +2 state. Extended X-ray absorption fine structure (EXAFS) investigations of these catalysts reflected higher degrees of CuO dispersion and Cu2+ dissolution into the TiO2 lattice for the tubular Cu/TiO2 catalysts. Absence of CuO bulk detection by a temperature-programmed reduction analysis for the tubular catalysts confirmed the high CuO-dispersion feature of the tubular catalysts. The dissolution of Cu2+ to form a Cu x Ti1- x O2 type of solid solution was improved by using an in-situ ion-intercalation method for Cu deposition on the nanotubes. A fraction as high as 40% for Cu2+ dissolution was obtained for the tubular catalysts while only 20% was obtained for the particulate catalysts. The Cu x Ti1- x O2 species were considered one form of the active sites on the Cu/TiO2 catalysts.
Preliminary assessment of rabies virus neutralizing activity, safety and immunogenicity of a recombinant human rabies antibody (NM57) compared with human rabies immunoglobulin (HRIG) in Chinese ...healthy adults.
Subjects were randomly (1:1:1) allocated to Groups A (20 IU/kg NM57), B (40 IU/kg NM57), or C (20 IU/kg HRIG). One injection was given on the day of enrollment. Blood samples were collected on days –7 to 0 (pre-injection), 3, 7, 14, 28, and 42. Adverse events (AEs) and serious AEs (SAEs) were recorded over a period of 42 days after injection.
All 60 subjects developed detectable rabies virus neutralizing antibodies (RVNAs) (> 0.05 IU /mL) on days 3, 7, 14, 28, and 42. The RVNA levels peaked on day 3 in all three groups, with a geometric mean concentration (GMC) of 0.2139 IU/mL in Group A, 0.3660 IU/mL in Group B, and 0.1994 IU/mL in Group C. At each follow-up point, the GMC in Group B was significantly higher than that in Groups A and C. The areas under the antibody concentration curve over 0–14 days and 0–42 days in Group B were significantly larger than those in Groups A and C. Fifteen AEs were reported. Except for one grade 2 myalgia in Group C, the other 14 were all grade 1. No SAEs were observed.
The rabies virus neutralizing activity of 40 IU/kg NM57 was superior to that of 20 IU/kg NM57 and 20 IU/kg HRIG, and the rabies virus neutralizing activity of 20 IU/kg NM57 and 20 IU/kg HRIG were similar. Safety was comparable between NM57 and HRIG.
A twin boundary is a special kind of grain boundary that plays an important role in the deformation process of nanocrystalline metals, as it may affect the migration of atoms and electrons in ...polycrystalline solids, resulting in different electrical and mechanical properties. In this study, plane twin structures were introduced into an electroplated copper film by an electroplating method that inserts an interlayer film with a very small current density (<3mA/cm2). It was found that the small-current interlayer formed a demarcation line for copper grain growth, and enhanced the twin boundaries by self-annealing at room temperature. Based on this, a method was developed to manufacture multi-plane twin boundaries to improve electron migration. Transmission electron microscopy, focused ion beam analysis, and secondary ion mass spectrometry were employed to examine this interesting phenomenon.
•A method is proved to enhance the formation of twin boundaries in the Cu films.•The low-current interlayer can trap higher-level carbon to limit Cu grain growth.•Multi-plane twin boundary can be manufactured to improve electron migration.
To clarify the photosynthetic mechanism contributing to the enhancement of intercropping advantages through co-ridge intercropping of maize and peanut, we conducted a field randomized block ...experiment under two phosphorus levels of 0(P0) and 180 kg P2O5·hm-2(P180) with flat intercropping of maize and peanut (FIC) as the control. We analyzed the effects of co-ridge intercropping of maize and peanut (RIC) and groove-ridge intercropping of maize and peanut (GIC) on crop leaf area index (LAI), SPAD values, CO2 carboxylation ability, photosystems coordination (ΦPSⅠ/PSⅡ), and intercropping advantage of yield. The results showed that RIC significantly increased SPAD value at the silking stage of intercropping maize, and significantly improved the apparent quantum yield of photosynthesis (AQY), maximum electron transfer rate (Jmax), maximum rate of Rubisco carboxylation (Vc,max), net photosynthetic rate at the CO2 saturation (Amax) and ΦPSⅠ/PSⅡ of intercropping maize compared with those of FIC and GIC at silking stag
The electrochemical behavior of polyacrylonitrile-based activated carbon cloth combined with a stainless steel current collector was examined using ac impedance spectroscopy. H2SO4, KOH, and KNO3 ...were employed as the electrolytes. The data presented in the impedance complex plane exhibit a semicircle at high frequencies followed by a vertical line at low frequencies. The high frequency data were found to be characteristic of the space charge region of the semiconducting oxide layer on the stainless steel, while the low frequency data depicted the double layer formation on the porous carbon. The double layer capacitance was found to decrease with the space charge resistance, which was potential dependent and a major contribution to the overall resistance of the carbon/stainless steel electrode. The electrolyte type affected the potential window employed in energy storage and thus the semiconducting behavior of the oxide layer. Both the n- and p-type semiconductors in depletion condition appeared within the potential window applied for the H2SO4 electrolyte, and this caused the presence of a peak capacitance. Only the n-type depletion condition was found in the KNO3 and KOH electrolytes with the p-type oxide situated in accumulation at the potentials applied, and thus, the capacitance was larger at more negative potentials.
Capacitance and conductivity enhancements of activated carbon fabric employed as electrodes of electrochemical capacitors (ECs) were achieved by electrochemical deposition of conducting poly(
...o-toluidine) (POT). Potentiodynamic polymerization of
o-toluidine onto the carbon in H
2SO
4 was employed for this carbon modification. The capacitance of the activated carbon was enhanced by superimposing the psuedocapacitance of poly(
o-toluidine) onto the double-layer capacitance of the carbon. Deposition of polyaniline was also conducted for the purpose of comparison. With the presence of the electron-donating methyl group in the phenyl ring, poly(
o-toluidine) is more effective than polyaniline in enhancing the capacitance of the carbon fabric. The specific capacitance of the electrodes increased with the amount of poly(
o-toluidine) deposited and more than twice of that of the bare carbon can be achieved. However, the capacitance per unit weight of the deposited polymer decreased with the extent of deposition, probably due to an increase of the ion migration resistance that increasingly obstructs some polymer from the access of ions. The resistance of the carbon electrode was found to decrease upon polymer deposition, and this was found to be more significant with poly(
o-toluidine) than with polyaniline. The low resistance resulting from poly(
o-toluidine) deposition enabled the assembly of capacitors of relatively high power densities, more than three times of that of a capacitor with the bare carbon.
Catalyst supports composed of titanate nanotubes were prepared from hydrothermal treatment on TiO
2
nanoparticles in NaOH followed by HCl washing. The nanotubes exhibited well-defined TiO
2
anatase ...phase after calcination at 400 °C. The nanotube aggregates and other commercially available TiO
2
nanoparticles, all with surface areas >300 m
2
/g, were impregnated with Cu and examined in selective catalytic reduction of NO with NH
3
. In catalyst preparation, the nanotubes were found to be more thermally stable than nanoparticles, withstanding agglomeration at elevated temperatures. The Cu species supported on the nanotubes showed a higher catalytic activity than those supported on the nanoparticles. Analysis with temperature programmed reduction, X-ray photoelectron spectroscopy, and NO adsorption reflected that the layeredtitanate feature of the tube wall was advantageous for even distribution of the Cu species, thus leading to the high-catalytic activity of the tubular Cu/TiO
2
catalyst.
