Enhancing the reinforcing efficiency in CNT nanocomposites the development of pyrene-based active dispersants.

Various preforms of carbon nanotubes (CNTs), such as fibers, yarns, or buckypapers (BP), have been developed over the last few years in order to fabricate advanced nanocomposites containing a high volume fraction of the reinforcing phase. However, a homogeneous dispersion and an even isolation of CNTs during the fabrication process of many preforms such as BP is often challenging, while the poor interaction between CNTs and the matrix also limits the final performance of the nanocomposites. Herein, a new route to overcome these two challenges simultaneously has been demonstrated based on an active dispersant (noted as Py-PEI) developed through the quaternization reaction of pyrene derivatives (Py-Br) and polyethylenimine (PEI).

Near-infrared-persistent luminescence/bioluminescence imaging tracking of transplanted mesenchymal stem cells in pulmonary fibrosis.

Human mesenchymal stem cells (hMSCs) are promising in the treatment of pulmonary fibrosis (PF). However, the behavior of hMSCs after transplantation, including dynamic translocation, location and survival, impeding the clinical application of hMSCs in PF is still ambiguous. Herein, we report an effective dual-labeling strategy combining endogenous bioluminescence imaging (BLI) and exogenous near-infrared-persistent luminescence (NIR-PL) imaging for in situ visualization of the transplanted stem cells.

Enhanced cyclability of Li-O batteries with cathodes of Ir and MnO supported on well-defined TiN arrays.

The cycling stability of Li-O batteries has been impeded by the lack of high-efficiency, and durable oxygen cathodes for the oxygen-reduction reaction (ORR) and the oxygen-evolution reaction (OER). Herein we report a novel TiN nanorod array-based cathode, which was firstly prepared by growing a TiN nanorod array on carbon paper (CP), and then followed by depositing MnO ultrathin sheets or Ir nanoparticles on the TiN nanorods to form well-ordered, three-dimensional (3D), and free-standing structured cathodes: TiN@MnO/CP and TiN@Ir/CP. Both cathodes exhibited good specific capacity and excellent cycling stability.

ZnO/Cu₂S/ZnO Multilayer Films: Structure Optimization and Its Detail Data for Applications on Photoelectric and Photocatalytic Properties.

Monolayer Cu₂S and ZnO, and three kinds of complex films, Cu₂S/ZnO, ZnO/Cu₂S, and ZnO/Cu₂S/ZnO, were deposited on glass substrates by means of radio frequency (RF) magnetron sputtering device. The impact of the thickness of ZnO and Cu₂S on the whole transmittance, conductivity, and photocatalysis was investigated. The optical and electrical properties of the multilayer were studied by optical spectrometry and four point probes.

[The Properties of an Infrared Hybrid Single Beam Spectrum].

A hybrid single beam spectrum ø(α)=αø(b1)+(1-α)ø(b2)=αø0e(-Kb1)+(1-α)ø0e(-Kb2) is introduced as the combination of two single beam spectra ø(b1) and ø(b2) from the same sample but with different pathlengths (b(1) and b(2)), where α(0＜α＜1) is the hybrid coefficient. The intensity of hybrid spectrum ø(α) can be controlled easily to the desired point by simply choosing an appropriate α. The experimental results showed that hybrid spectrum ø(α) is very nearly identical to ø(b)=ø(0)e-K(b(2)-αb(2)+αb(b)) under appropriate conditions, namely ø(α)≈ø(b) , where ø(b) is the single beam spectrum of the real sample with the pathlength of b(2)-αb(2)+αb(1).

A multi-walled carbon nanotubes based molecularly imprinted polymers electrochemical sensor for the sensitive determination of HIV-p24.

To develop a rapid, simple and sensitive method for the determination of human immunodeficiency virus p24 (HIV-p24), a novel molecularly imprinted polymers (MIPs) electrochemical sensor was constructed on the surface of a multi-walled carbon nanotubes (MWCNTs) modified glassy carbon electrode (GCE) by surface polymerization using acrylamide (AAM) as functional monomer, N,N'-methylenebisacrylamide (MBA) as cross-linking agent and ammonium persulphate (APS) as initiator. Each modification step was carefully examined by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and scanning electron microscope (SEM). The proposed MIPs electrochemical biosensor exhibited specific recognition to HIV-p24 and displayed a broad linear detection range from 1.

MIPs-graphene nanoplatelets-MWCNTs modified glassy carbon electrode for the determination of cardiac troponin I.

An electrochemical sensor with high selectivity in addition to sensitivity was developed for the determination of cardiac troponin I (cTnI), based on the modification of cTnI imprinted polymer film on a glassy carbon electrode (GCE). The sensor was fabricated by layer-by-layer assembled graphene nanoplatelets (GS), multiwalled carbon nanotubes (MWCNTs), chitosan (CS), glutaraldehyde (GA) composites, which can increase the electronic transfer rate and the active surface area to capture a larger number of antigenic proteins. MWCNTs/GS based imprinted polymers (MIPs/MWCNTs/GS) were synthesized by means of methacrylic acid (MAA) as the monomer, ethylene glycol dimethacrylate (EGDMA) as the cross linker α,α'-azobisisobutyronitrile (AIBN) as the initiator and cTnI as the template.

Native Defect Luminescence of Zinc Oxide Films and Its Potential Application as White Light Sources.

ZnO light-emitting diodes (LEDs) have an enormous potential in lighting applications. The major issue to be resolved is the generating and control of light emissions. This issue arises from the variation and combination in LED wavelength.

[Study on the Measurement of Infrared Spectrum for Discontinuous Sample].

The samples to be measured with infrared instrument are usually required to be homogeneous. However, discontinuous sample is quite common in the real infrared measurements, such as, high viscosity liquids containing air bubbles. In this paper, the spectral distortion of discontinuous sample was analyzed with simple theoretical simulation and experimental examples quantitatively.

A Method to Obtain a Good Infrared Spectrum of the Wet Acetone Gas Sample without Any Drying Pretreatment.

Water vapor in the beam of a Fourier transform infrared (FTIR) spectrometer or/and in a gas cell is a major source of interference in the infrared measurement of a gas sample. In general, in order to eliminate the effect of water vapor, we have to completely remove these molecules before the measurement of any spectrum. Herein, we provide an approach to collect an IR spectrum of a gas (wet acetone) sample free from water vapor interference without any drying pretreatment.

[How to Remove Water Absorption Bands Completely from IR Spectra of Aqueous Solution].

Infrared spectral studies of aqueous solution have been severely limited by the strong water absorption. Usually, it is very difficult to experimentally achieve perfect compensation between the amount of water that contributes to the sample and background spectra. In the present paper, we introduced a new method to make the infrared bands of water disappear during the measurement of an infrared spectrum for aqueous solution.

Combined IR/NIR and density functional theory calculations analysis of the solvent effects on frequencies and intensities of the fundamental and overtones of the C ═ O stretching vibrations of acetone and 2-hexanone.

Vibrational overtone studies primarily focus on X-H stretching overtone transitions, where X is an atom like C, O, N, or S. In contrast, the studies on the C ═ O stretching overtones are very scattered. To advance the research in this field, we measured the fundamental, first, and second overtones of the C ═ O stretching vibration of acetone and 2-hexanone in n-hexane, CCl4, and CHCl3, as well as in the vapor phase using FT-IR/FT-NIR spectroscopy.

Concept and properties of an infrared hybrid single-beam spectrum and its application to eliminate solvent bands and other background interferences.

For infrared (IR) spectral measurements, if a quality single-beam background spectrum with desired intensity could be obtained, the contributions from solvent and other background components could be completely suppressed and their bands would not appear in a final transmittance/absorbance spectrum. In order to achieve this ideal but difficult goal, the concept of hybrid single-beam spectrum is introduced in this paper. The hybrid single-beam spectrum (φ h) is defined as a mixture of two single-beam spectra (φ b1 and φ b2) of the same sample but with different pathlengths (b1 and b2), namely, φ h = αφ b1+(1-α)φ b2, where α (0 ≤ α ≤ 1) is the component factor.

[Anomalous absorption and a qualified far infrared spectrum].

The ideal 100% line could not be obtained when the content of water vapor in the spectrometer is constant but high during the whole procedure of a far-infrared spectrum collection. This result indicates that anomalous absorption phenomenon takes place in high relative humidity atmosphere. In the present paper, the influences of the relative humidity of ambient air and spectral resolution on anomalous absorption were studied.

[Absorbance of infrared bands and anomalous absorption].

To remove the background signals from an IR spectrum is very useful and ideally all that remain in an IR spectrum are the desired absorption bands. Unfortunately, the removal of background bands is not always completely effective. In the present paper, an absorbance spectrum was obtained by scanning the same sample (polystyrene film or stearic acid KBr disc) both in background and sample single-beam measurements.

A new method to obtain Fourier transform infrared spectra free from water vapor disturbance.

Infrared absorption bands due to water vapor in the mid-infrared regions often obscure important spectral features of the sample. Here, we provide a novel method to collect a qualified infrared spectrum without any water vapor interference. The scanning procedure for a single-beam spectrum of the sample is divided into two stages under an atmosphere with fluctuating humidity.

Infrared band assignments and structure of even-numbered 2-alkyl-7,7, 8, 8-tetracyanoquinodimethane in cast films--two components of the CH2 scissoring vibrations not related to crystal field splitting.

Infrared (IR) spectra were measured for 2-octyl-, 2-dodecyl-, and 2-octadecyl-7, 7, 8, 8-tetracyanoquinodimethane (C8TCNQ, C12 TCNQ and C18 TCNQ) in cast films, and it was found that each spectrum shows two components for the CH2 scissoring band at 1 471 and 1 462 cm(-1). Polarized IR measurements showed that the micro-crystallites in the cast films take a random orientation in the plane of the plate. The intensity ratio of the two bands at 1 471 and 1 462 cm(-1) (I1 471/I1 462) decreases observably with the increase in the length of the alkyl chain.

[Preparation and structural characterization of mixed LB films of TMB * TCNQ and stearic acid].

Mixed LB films of the CT complex of TMB * TCNQ and stearic acid (SA) were prepared. The structures, molecular orientation and morphology of the mixed LB films were characterized by IR, UV-Vis-NIR, XRD and AFM. Our results show that TMB * TCNQ could be deposited on solid substrates by mixing with SA.

A method to collect an infrared spectrum in solution.

Herein we report a new method to collect a qualified infrared spectrum of a solute in solution by two solvent cells with different thickness during background single-beam spectrum scanning. By collecting the background spectrum with two cells (two stages), we successfully achieved accurate solvent compensation between a sample and a reference, namely, the solvent amounts in the sample and background measurements could become congruent. Therefore, the solvent bands were thoroughly suppressed in the infrared spectrum and a qualified spectrum of the solute was obtained.

Hydrothermal synthesis of single-crystalline antimony telluride nanobelts.

The single-crystalline Sb2Te3 nanobelts were successfully synthesized by a novel and convenient surfactant-assisted hydrothermal approach. The ionic surfactant AOT acted as the shape controller in the synthetic process. We believe that this synthetic route could be applied to obtain other low-dimensional semiconducting telluride nanostructures.

Synthesis of neodymium hydroxide nanotubes and nanorods by soft chemical process.

A facile soft chemical approach using cetyltrimethylammonium bromide (CTAB) as template is successfully designed for synthesis of neodymium hydroxide nanotubes. These nanotubes have an average outer diameter around 20 nm, inner diameter around 2 nm, and length ranging from 100 to 120 nm, high BET surface area of 495.71 m(2) g(-1).

Catalytic properties of silica/silver nanocomposites.

The catalytic properties of silver nanoparticles supported on silica and the relation between catalytic activity of silver particles and the support (silica) size are investigated in the present article. The silver nanoparticles with 4 nm diameters were synthesized and were attached to silica spheres with sizes of 40, 78, 105 nm, respectively. The reduction of Rhodamine 6G (R6G) by NaBH4 was designed by using the SiO2/Ag core-shell nanocomposites as catalysts.

Synthesis and herbicidal activity of N,N-diethyl-3-(arylselenonyl)-1H-1,2,4-triazole-1-carboxamide.

Based on the carbamoyl triazole herbicide Cafenstrole, 12 novel selenium-containing compounds were designed and synthesized. All of the compounds were characterized and confirmed by IR, 1H NMR, and high-resolution mass spectroscopy. The bioassay tests showed that some of the compounds (C2, C4, C(7-8), and C12) exhibited good inhibitory activity against cucumber (Cucumis sativus L.

Structure and catalytic properties of magnesia-supported copper salts of molybdovanadophosphoric acid.

The structure and stability of magnesia-supported copper salts of molybdovanadophosphoric acid (Cu(2)PMo(11)VO(40)) were characterized by different techniques. The catalyst was prepared in ethanol by impregnation because this solvent does not hurt texture of the water-sensitive MgO and Cu(2)PMo(11)VO(40). The Keggin-type structure compound may be degraded partially to form oligomerized polyoxometalate when supported on MgO.

Systematic synthesis and characterization of single-crystal lanthanide phenylphosphonate nanorods.

Using low-temperature hydrothermal methods, nanoscale lanthanide phenylphosphonates species with different morphologies, namely, nanoparticles and nanorods, have been systematically synthesized. The possible growth mechanism of these nanorods was discussed. X-ray diffraction, transmission electron microscopy, electron diffraction, and photoluminescence spectra were used to characterize these materials.