Mass Ratio Of Core Research Articles

Structural design and synthesis of new MOO3-x interlayer bi-functional nanomaterials for enhanced up-conversion luminescence properties

A novel imaging materials based on bi-functional Fe3O4@MOO3-x@YF3:Yb/Er nanoparticles (NPs) with strong up-conversion luminescence and magnetic properties was designed and synthesized by inlaying MOO3-x with localized surface plasmon resonance (LSPR) and ferromagnetic property in the bi-functional Fe3O4@YF3:Yb/Er NPs. The morphology, structure and properties of Fe3O4@MOO3-x@YF3:Yb/Er NPs are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), photoluminescence (PL) spectra, UV–Vis-NIR spectrophotometer and superconducting quantum interference devices (SQUID). It was found that the experimental conditions (reaction temperature, reaction time, the mass ratio of core:shell and oxygen pressure in heat treatment) have a certain effect on the oxygen defect concentration of the MOO3-x interlayer. XRD also showed the crystal structure of Fe3O4, Fe3O4@MOO3-x and Fe3O4@MOO3-x@YF3:Yb/Er NPs. The SEM and TEM results showed that the average grain size of the prepared NPs were 200 nm. The SQUID and PL results showed that the Fe3O4@MOO3-x@YF3:Yb/Er NPs have stronger magnetism (14.3 emu/g) and excellent up-conversion luminescence performance (the emission peak at 525 nm is nearly 20 times higher than the corresponding emission intensity of the Fe3O4@YF3:Yb/Er). The Fe3O4@MOO3-x@YF3:Yb/Er NPs can be easily used to magnetic resonance and fluorescence dual-mode image-guided visual delivery drug and also increase the accurate diagnosis and treatment effect of malignant tumor.

A novel mixed potential NH3 sensor based on TiO2@WO3 core–shell composite sensing electrode

The TiO2@WO3 core-shell composite with mass ratio of core and shell4:1 was prepared by a hydrothermal synthesis method using sodium tungstate dehydrate, nitric acid and commercial TiO2 powder as raw materials. A novel mixed potential NH3 sensor was fabricated by using above-mentioned TiO2@WO3 as sensing electrode and La10Si5.5Al0.5O27 as solid electrolyte. X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) were used to characterize the morphology and structure of the samples. The sensor response to NH3 was examined at 400∼550°C. The experimental results indicated that the sensor based on TiO2@WO3 sensing electrode possessed greatly enhanced NH3 sensing properties including higher and more stable response value and faster response rate compared to the sensor using TiO2, WO3 or TiO2-WO3 mixture sensing electrode under the same conditions. The responding potential values of the sensor with TiO2@WO3 sensing electrode exhibited a linear dependence on the logarithm of the NH3 concentrations. The highest NH3 sensitivity of 74.8mV/decade was achieved at 450°C. In the meantime, the sensors also showed well anti-interference capability to CH4, CO2 and H2, but noticeable cross sensitivity toward NO2 was observed. O2 effect on responding signal could be calibrated by predetermining O2 content.

Preparation and application of melamine-formaldehyde photochromic microcapsules

Melamine-formaldehyde microcapsules encapsulating photochromic compounds with particle size less than 5μm had been prepared by in situ polymerization, and their application in textile was also studied. The Fourier transform infrared spectroscopy (FTIR), biological microscope and laser particle analyzer were utilized to characterize the structure, morphology, size and size distribution of melamine-formaldehyde photochromic microcapsules. The UV–visible spectrophotometer was used for monitoring the UV–vis absorption of different mass fraction of photochromic compounds in dioctyl phthalate (DOP) solvent and the kinetics and fatigue resistance of photochromic microcapsules and photochromic print cloth. As a result, the mixed photochromic solution of photochromic compound and DOP solvent appeared maximum absorption peak in a certain wavelength range after exposed in a mercury lamp (375W) for 10min when the mass ratio was 2%. The lifetime of photochromic microcapsules could extend from 6–7h to 69–75h under continuous UV, when stirring rate, emulsification time and mass ratio of core materials/wall materials were 1000rpm, 5min and 1:1, respectively. Meanwhile the photochromic painting paste had excellent water resistance, acid/alkali resistance, soaping resistance, light resistance and fatigue resistance.

Research on Core-Shell TiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> by one-Step Hydrothermal

The core-shell structure’s synthesis process by one-step hydrothermal method has remarkable peculiarities, such as simple procedures and short production cycles. In order to get the precursor with the core-shell structure, it’s important to study the technological parameters. In this paper, the pH value, the concentration of AlCl3,the mass ratio of core and shell , the hydrothermal temperature and time were detailed discussed. In order to get well-coated core-shell material, the technological parameters were the pH value=8.5-9.8, the concentration of AlCl3 0.040－0.050g/ml, Al2O3：TiO2=10％－28.5％, the hydrothermal temperature 200°C and the hydrothermal time 3 hours.

Research on The Parameters .of Core-shell TiO2/Al2(OOH)2 by One-step Method

The core-shell structure's synthesis process by one-step hydrothermal method has remarkable peculiarities, such as simple procedures and short production cycles. In order to get the precursor with the core-shell structure, it's important to study the technological parameters. In this paper, the pH value,the concentration of AlCl3,the mass ratio of core and shell, the hydrothermal temperature and time were detailed discussed. In order to get well-coated core-shell material, the technological parameters were the pH value=8.5-9.8, the concentration of AlCl3 0.040-0.050g/ml, Al2O3:TiO2=10%-28.5%, the hydrothermal temperature 200 and the hydrothermal time 3hours.

Preparation and characterization of double‐MF shell microPCMs used in building materials

AbstractA kind of double‐shell heat energy storage microcapsule was prepared used melamine formaldehyde (MF) resin as shell material, and the properties of the microcapsules were investigated. A phase change material, with melt point of 24°C and phase transition heat of 225.5J/g, was used as core. The microcapsules would be used in indoor walls to regulate the temperature and save energy. The surface morphological structure was examined by means of scanning electron microscopy. The strength of the shell was evaluated through observing the surface change after pressure by means of scanning electron microscopy. The average diameter of the microcapsules was 5 μm ∼ 10 μm. Diameter of 1 μm ∼ 5 μm could also be obtained by using different stirring speeds. The globular surface was smooth and compact. The thickness was 0.5 μm ∼ 1 μm. Also, the melting point of the microcapsules was 24.7°C, nearly equal to the pure phase change material. The DSC results make clear that the polymer shell of the microcapsules does not influence the properties of the phase change material. It was also found that the avoiding penetration property of the double‐shell microcapsules was better than that of single shell, and the average diameter of 5 μm was better than 1 μm. With the increase of ratio of the core material, the compactability decreased, and the shell thickness decreased. The mass ratio of core and shell was 3 : 1 to ensure that the microcapsules had good heat storage function. The measuring test showed that the microcapsules did not rupture at a pressure of 1.96 × 105 Pa. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1755–1762, 2005