Advanced Materials Research Vol. 680

Abstract: A novel biocompatible Fe2+-chitosan (CTS)/citric acid modified carbon nanotube (CA-CNTs) composite (Fe2+-CTS/CA-CNTs) has been successfully synthesized by covalent bonding and crosslinking chemistry, followed by the reduction. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis spectrum, X-ray diffraction (XRD), inductively coupled plasma (ICP), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM) techniques. The results show that the CTS has been successfully grafted to the CA-CNTs carrier and Fe2+ ions are absorbed on the CTS by coordination bond mode. It was found that the Fe2+-CTS/CA-CNTs composite shows good magnetic properties with a low ratio of remanence to saturation magnetization and is in a superparamagnetic state at room temperature. It is believed that the Fe2+-CTS/CA-CNTs composite will be potential for application in MRI.

Abstract: Automotive seating fabrics are assembled into complete trims by sewing process, which plays an important role on the quality of automotive seat. This paper was written based on study of the influence of the distance between stitch and selvage, gauge distance, and the type of sewing thread on automotive woven seating fabric. Furthermore, the influences of each factor and the optimum parameters were obtained by the single-factor experiments and orthogonal experiment. The results showed that sewing strength and breaking elongation are increased with increasing the distance between stitch and selvage, and are decreased with the gauge distance. On the other hand, when the distance between stitch and selvage is 8cm, the gauge distance is 2cm, and the fineness of sewing thread is 168tex, its twist is 34.18, and the break strength 72.44N, sewing strength and elongation of this kind of seating fabric are the highest.

Abstract: Titanium alloy TA6V is chemically inert and which only reacts at high temperatures with various gas, can be used in medicine for medical implants through the process of selective laser sintering. It also shows a low toxicity to the human body and adheres well as implant in the human body. Therefore titanium alloy powder necessary for selective laser sintering must present a high degree of purity. This can be achieved by getting titanium alloy powder process hydride-milling-dehydrate.

Abstract: New types of polymer hydrogels and nanocomposites, i.e., nanocomposite gels (NC gels) and soft, polymer nanocomposites (M-NCs), with novel organic/inorganic network structures have been fabricated. Both NC gels and M-NCs were synthesized by in-situ free-radical polymerization in the presence of exfoliated clay platelets in aqueous systems and were obtained in various forms and sizes with a wide range of clay contents. Here, disk-like inorganic clay nanoparticles act as multi-functional crosslinkers to form new types of network systems. NC gels have extraordinary optical, mechanical, and swelling/deswelling properties, as well as a number of new characteristics relating to optical anisotropy, polymer/clay morphology, biocompatibility, stimuli-sensitive surfaces, micro-patterning, self-healing, etc. The M-NCs also exhibit dramatic improvements in optical and mechanical properties including ultra-high reversible extensibility and well-defined yielding behavior, despite their high clay contents. The M-NC also showed thermoresponsive cell adhesion/detachment. Thus, the serious disadvantages (intractability, mechanical fragility, optical turbidity, poor processing ability, low stimulus sensitivity, etc.) associated with the conventional, chemically-crosslinked polymeric materials were overcome in NC gels and M-NCs.

Abstract: Ternary polycrystalline Zn1xCdxO semiconductor films with cadmium content (x) ranging from 0 to 0.23 were obtained on quartz substrate by pulse laser deposited (PLD) technique. X-ray diffraction measurement revealed that all the films were single phase of wurtzite structure grown on c-axis orientation with its c-axis lattice constant increasing as the Cd content x increasing. Atomic force microscopy observation revealed that the grain size of Zn1xCdxO films decreases continuously as the Cd content x increases. Photoluminescence measurements showed that the band gap decreases from 3.27 to 2.78 eV with increasing the Cd content x. Increasing the Cd content x also leads to the broadening of the emission peak. The shift of PL emission to visible light as well as the decrease of resistivity makes the Zn1xCdxO films potential candidate for optoelectronic device.

Abstract: Zr-Ga co-doped ZnO transparent conductive films were prepared on glass substrates by DC magnetron sputtering at room temperature. The influence of sputtering power on the structural, electrical and optical properties of Zr-Ga co-doped ZnO films was investgated by X-ray diffraction, scanning electron microscopy (SEM), digital four-point probe and optical transmission spectroscopy. The lowest resistivity of the Zr-Ga co-doped ZnO films is 3.02×10-4Ω﹒cm and the average transmittance of the films is over 90% in the visible range. The obtained optical band gap of these films is much larger than of pure ZnO (3.34 eV).

Abstract: Series samples ZnS: Cu²⁺ have been prepared by Liquid-phase method and the final productivity has a great improvement compared with traditional method. Different concentration thioglycolic acid (TGA) modified combining nanoparticle makes water soluble ability better. When precipitating agent water and ethanol volume ratio is 3:1, sample production rate is the highest. Under XRD theoretical calculation ,the size of the series of samples are about 16nm , and the sample size is 18 nm while using Laser Particle Size Analyzers（Rise - 2208）measured. Series sample shows strong absorption under 200 nm to 340 nm range. Through absorption spectrum calculating the forbidden band width is about 3.58 eV. Under 210 nm of excitation, the emission spectrum shows that the strongest peak locates in 425 nm which belongs to Cu^{2 +} ions’ t2 transition.

Abstract: As the consumption of honey is booming because of its multiple health-promoting effects, the possible health risks resulting from long-term exposure to metals contained in this honey need to be evaluated. The concentrations of heavy metals (Pb, Cd, Cu, As,Hg and Zn) in three sources of honeys collected from China, were determined by flame atomic absorption spectrophotometry (FAAS), graphite furnace atomic absorption spectrometry (GF-AAS) and hydride generation-atomic fluorescence spectrometry (HG-AFS) after microwave-assisted digestion. The rangs obtained for the element analyzed in ug kg^-1 were as follow:Cd(4.9)Comparing with safety intake levels for these heavy metals recommended by US Environmental Protection Agency (US EPA) and Joint FAO/WHO Expert Committee on Food Additives (JECFA), both the Hazard Quotient (HQ) values for single heavy metal and the Hazard Index (HI) value for all six heavy metals were far below 1, indicating no chronic-toxic risks from these heavy metals due to daily consumption of 0.01 kg of honey for a 70 kg individual.

Abstract: The effects of fly ash on heavy metal uptake by rice and Cd, Pb, Cu and Zn availibility in contaminated acidic soil were investigated in this study. The fly ash was added at 0, 20 and 40 g·kg^-1 dry weight soil, respectively. The results indicated that the addition of 20 g·kg^-1 fly ash significantly improved dry weights of leaves, stems and roots of rice. While at the rate of 40 g·kg^-1 fly ash, the dry weithts of leaves and stems of rice decreased. It was also showed that the application of fly ash substantially increased soil pH values from 4.0 to 5.1 and 6.4, and the higher increment was improved by the higher dosage. Further more, the addition of fly ash substantially decreased the avalibility of heavy metals, and the higher amendment dosage resulted in the lower NH₄NO₃ extractable heavy metal concentrations. These results demonstrated that the application of fly ash at 20 g·kg^-1 might be an effective strategy to decrease rice metal uptake and remediate heavy metal contaminated acidic soil.

Abstract: Magnetic carbon spheres (MCSs) with hierarchical pore structure were designed and controllably synthesized using corn starch as carbon source and iron nitrate as metal source by a combined procedure of enzymolysis, pre-oxidation and catalytic carbonization. The results show that after enzymolysis, the porous starch precursor inherits the morphology of original starch with round shape and has a number of honeycomb-like pores of ca.1 μm on the outside surface. It has been found that the MCSs materials with hierarchical porous structure can be synthesized only from the pre-oxidized porous starch by the catalytic carbonization technique, evidenced that the pre-oxidation of carbon source is a dominating factor governing the formation of MCs with hierarchical pore structure. Compared with the porous starch, the pores on the surface of the MCSs shrink slightly and vary in a range of 0.3-0.6 μm.