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  • Author: Hai-Feng Liu, x
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Abstract

The granulation of blast furnace (BF) slag with water quenching has many disadvantages, such as high water consumption and difficulty in heat recycling. The dry granulation technology to treat the BF slag is very important. The application of BF slag depends on the content of amorphous solids in the slag after treatment. The research on the activation energy of crystallization of amorphous solids in BF slag is the foundation to find out the reasonable cooling speed during dry granulation of molten slag. So it is of theoretical and practical significance to be analyzed. The activation energy of crystallization of amorphous solids in BF slag (E) was 108.90 kJ/mol. Based on the results; the required cooling rate for BF slag from 1723 K to 973 K was more than 100 K/s. The process and equipment for the dry slag granulation (DSG) technology was desired. The semi-industrial experimental results was that the volume of recycling hot air was 2020 m3 with 867 K and the content of amorphous solids in granulated slag was about 96 %, which had the similar activity with the slag by water quenching. The problems of the experiment were that the treated slag had a crusting phenomenon, the grain size was not uniform and the slag cotton was produced during BF slag treatment, which needed to be further researched.

Abstract

Novel graft copolymers of 2-(dimethylamino)ethyl methacrylate (DMAEMA) with N-vinylpyrrolidone (NVP) were designed and synthesized by the free radical copolymerization of DMAEMA with precursor polymers of vinyl-functionalized poly(N-vinylpyrrolidone) (PVP). The ability of the PVP- grafted copolymers to bind and condense DNA was confirmed by ethidium bromide displacement assay, agarose gel electrophoresis and transmission electron microscopy. The presence of PVP in the copolymers had a favorable effect on the biophysical properties of polymer/DNA complexes. Colloidal stable complexes obtained from the copolymer systems, were shown to be separate, uniformly spherical nanoparticles by transmission electron microscopy. The approximate diameter of the complexes was 150–200 nm, as determined by dynamic light scattering studies. These results confirm an important role played by the PVP grafts in producing compact stable DNA complexes. The ζ-potential measurements revealed that the incorporation of the PVP grafts reduced the positive surface charge of polymer/DNA complexes. The cytotoxicity of the copolymers decreased with an increasing fraction of PVP. Furthermore, in vitro transfection experiments with these copolymers showed improved ability of transfection in cell culture, demonstrating an important role for PVP grafts in enhancement of the transfection efficiency.

Abstract

In this paper, the mechanical properties (compression and impact behaviours) of three-dimension structure (3D-structure) composites based on warp-knitted spacer fabrics have been thoroughly investigated. In order to discuss the effect of fabric structural parameters on the mechanical performance of composites, six different types of warp-knitted spacer fabrics having different structural parameters (such as outer layer structure, diameter of spacer yarn, spacer yarn inclination angle and thickness) were involved for comparison study. The 3D-structure composites were fabricated based on a flexible polyurethane foam. The produced composites were characterised for compression and impact properties. The findings obtained indicate that the fabric structural parameters have strong influence on the compression and impact responses of 3D-structure composites. Additionally, the impact test carried out on the 3D-structure composites shows that the impact loads do not affect the integrity of composite structure. All the results reveal that the product exhibits promising mechanical performance and its service life can be sustained.

Abstract

The water poverty index (WPI) is a holistic and objective reflection of the relationship between degree of water shortage and development of social economy. Based on the analysis of the classical WPI evaluation model, the model is optimized by the principal component analysis method. Then, an optimized WPI evaluation model based on PCA is proposed, and the experimental results verify the validity of the proposed model. When the optimization model is applied to the water resources data of Beijing region, the efficiency of WPI evaluation is improved by about 4%.On the other hand, the optimization model is used to evaluate the WPI values of different urban and rural areas, and the results are satisfactory. On this basis, this paper designs the water environment prediction model and the Shan-gan-ning district was tested for the local future water resources situation and provides theoretical support.

Abstract

A new and efficient method for the synthesis of novel 4β-isocyanopodophyllotoxins as a valuable building block for the synthesis of versatile bioactive podophyllotoxin analogues under both classical and ultrasonic conditions was developed. In general, significant improvements in rates of reaction and yields of sonochemical reactions relative to the classical ones were observed.

Abstract

To enhance the physical properties of copolymer-polyamide (CO-PA), a sequence of nanocomposites based upon CO-PA and chemically reduced graphene oxide (CRGO) nanoplatelets were prepared by in-situ reduction using hydrazine hydrate. Graphene oxide (GO), prepared by the improved Hummers method, was used to fabricate CRGO nanaoplatelets. Atomic-force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis showed that the thickness and the width of GO was about 0.9 nm and 1 μm, respectively. An abundance of oxygen-containing functional groups were introduced onto the GO sheets. XRD and SEM analysis showed that CRGO nanoplatelets were well dispersed in the CO-PA matrix with the appropriate CRGO content. TGA and DSC analysis demonstrated that CRGO nanoplatelets can significantly improve the thermal stability, glass-transition temperature, crystallization temperature of the composites. The mechanical properties of the nanocomposites were improved significantly with the appropriate increment of CRGO nanoplatelets content, though the elongation at break of the composites decreased with the increase of CRGO nanoplatelets content. The electrical conductivity test showed a significant increase in electrical conductivity from an insulator to almost a semiconductor with increasing CRGO nanoplatelets content. And at 1.0 wt% CRGO content, the electrical percolation threshold of the nanocomposites was found.

Arising in the context of random matrix theory, the coupled Kadomtsev-Petviashvili (KP) systems have been a subject of active studies. In this paper, a coupled KP system with three potentials is investigated with symbolic computation, and the Darboux transformations of its reduced equations are obtained. Moreover, the multi-soliton-like solutions of the coupled KP system are derived. Those solutions could be of some value for the studies in the context of random matrix theory.

Abstract

Lightweight and low-cost organic photovoltaics (OPVs) hold great promise as renewable energy sources. The most critical challenge in developing high-performance OPVs is the incomplete photon absorption due to the low diffusion length of the carrier in organic semiconductors. To date, various attempts have been carried out to improve light absorption in thin photoactive layer based on optical engineering strategies. Nanostructure-induced light harvesting in OPVs offers an attractive solution to realize high-performance OPVs, via the effects of antireflection, plasmonic scattering, surface plasmon polarization, localized surface plasmon resonance and optical cavity. In this review article, we summarize recent advances in nanostructure-induced light harvesting in OPVs and discuss various light-trapping strategies by incorporating nanostructures in OPVs and the fabrication processing of the micro-patterns with high resolution, large area, high yield and low cost.