Advanced Materials Research Vol. 680

Abstract: Influence of nanoflakes and melt-spun ribbons on the nitrogenation temperature f Sm₂Fe₁₇ was investigated. The microstructure, phase structure, properties of the specimens before and after nitrogenation have been discussed. It is interesting found that hard magnetic Sm₂Fe₁₇N₃ flakes have been synthesized by surfactant-assisted high energy ball milling and nitriding Sm2Fe17 in 3 psi of N2 gas at lower temperature 300 °C and 350 °C for 3 h. The synthesized Sm₂Fe₁₇N₃ flakes still retained nanostructure and obtained a coercivity of 3.56 kOe. For the melt-spun ribbons, it needs a higher nitrogenation temperature and longer time to obtain the same coercivity values as the nanoflakes.

Abstract: This paper uses fuzzy pairwise comparison method to determine the weight values of assessment indexes of low temperature material of storage tank, which is proposed based on Chinese traditional complementary thought pattern by Chen Shouyu. For the little difference between the results of study by this method mentioned in this paper and analytical hierarchy process, the main reason in essence is given finally.

Abstract: A new type of gradient boron alloyed composite material, containing boron alloyed core layers and stainless steel coatings around the core, were designed and prepared by composite casting and hot rolling. The evolution of microstructures, phases and precipitations, as well as their influence on hot rolling process and performance are investigated. A mixture of austenitic matrix and uniformly distributed borides are obtained in the hot rolled stainless steel with 2-2.5 % boron, while massive borides are in the length of 80-120 μm together with micro gaps at the interface between the borides, and the matrix is remained after hot rolling for the core layers with higher boron contents. Hot deformation would be hindered since more precipitations of these orthorhombic or tetragonal phases occur with an increase of the boron concentration in the core layers.

Abstract: In this paper, Finite element modeling of the impact of the Kevlar woven fabric using hybrid element analysis (HEA) method has been carried out to find out a suitable ratio between area of solid elements used at impact region and area of shell elements used away from impact region. Three HEA models: about one time, two times and three times of the projectile’s diameter with 200 m/s impact velocities are constructed. The solid and shell elements with variable nodal thickness are joined together using tied interfaces in order to ensure that there are no artificial reflections of the longitudinal wave at the interface. The effect of the different ratio of local area and global area on the ballistic performance of the fabric is discussed.

Abstract: Through application research of new type fiber in the sports equipment field, understand its effects on sports equipments and advantages, and grasp its booster function in the improvement of development system and sport performance during the development process of sports equipments.

Abstract: Tumor necrosis factor-alpha converting enzyme (TACE) is a very important membrane-bound proteinase, and it can cut a lot of membrane proteins to their released form. Many of the substrates of TACE are critical protein factors, such as IL-6, TNF-alpha, EGF receptor. Therefore, TACE has been a hopeful drug targets in many diseases. However, selective inhibitors against TACE with high specificity has yet been developed successfully, partly due to the lack of the understanding of the TACE substrate interaction details. To solve this problem, here we build a computational complex model of the TACE catalytic domain and its substrate peptide using the protein design software Rosetta. To further optimize the complex model, molecular dynamics analysis was performed in NAMD with explicit water molecules. The result showed that our complex model is a pretty reliable intermediate model for TACE and its peptide substrate. This complex model could be very useful for further study of the substrate specificity and selectivity of TACE.

Abstract: Using sodium citrate as reducing agent, different sizes of gold nanoparticles(GN) were prepared, and were modified by platelet-derived growth factor (PDGF) aptamer to obtain stable aptamer-nanogold probes (Apt-GN). The probe specifically combined with PDGF-AA to form Apt-GN-PDGF-AA clusters that exhibited a resonance Rayleigh scattering (RRS) peak at 550 nm. The RRS intensity ΔI_550nm was linear to the PDGF-AA concentration in the range of 0.33-40 ng/ml. The probe has strong catalysis of the Fehling reagent-glucose Cu₂O particle reaction that can be monitored by RRS technique at 610 nm, but the cluster is very weak. When PDGF-AA concentration increased, the Apt-GN decreased, and the RRS intensity at 610 nm decreased. The decreased RRS intensity ΔI_610nm was linear to PDGF-AA concentration in the range of 0.03-26.67 ng/mL. Accordingly, two new aptamer-nanogold RRS methods were established.

Abstract: In pH 6.6 Na₂HPO₄- citric acid buffer solution and in the presence of KCl, the immunoreaction between hCG and nanosilver-labeled anti-hCG took place, the immunonanosilver-complex was formed and deposited, caused the resonance Rayleigh scattering (RRS) intensity at 510 nm decreased. In the optimal condition, the decreased RRS intensity responds linearly with the concentration of hCG over 0.125-1.75 µg/mL. Based on this, a new and simple RRS method has been proposed for the determination of hCG in serum samples, with satisfactory results.

Abstract: Highly sensitive and selective surface-enhanced resonance Raman scattering (SERRS) spectral detection technique are developed by combining the functional nucleic acid (FNA) including aptamer and DNAzyme, and nanoparticle such as gold/silver (NG/NS) aggregation. The recent progress of SERRS was reviewed in this paper.

Abstract: The objective of this study was to synthesize a new organic selenium compound, chitooligosaccharide-selenium (COSSe), and evaluate its antioxidant abilities on hydroxyl radicals, super oxide radicals and DPPH in vitro. Sodium selenite and chitooligosaccharide (COS) were used to synthesize COSSe by chemical method. The yield was 37.26% and the content of selenium (Se) was 9.02mg/g. COSSe was characterized by ultraviolet (UV) and infrared (IR) techniques. The results proved the successful synthesis of COSSe. The antioxidant activities on hydroxyl radicals, super oxide radicals and DPPH of COSSe were investigated. The results showed that antioxidant activities were concentration related in the setting concentration range and the antioxidant effects of COSSe were totally better than that of COS. The scavenging rates on hydroxyl radicals, superoxide radicals and DPPH of 2.5mg/mL COSSe were 71.19%, 64.54% and 69.78%, respectively. This research provides a possible application of COSSe as a low toxic and effective organic Se-enriched healthy product.